11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/mm/memory.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 51da177e4SLinus Torvalds */ 61da177e4SLinus Torvalds 71da177e4SLinus Torvalds /* 81da177e4SLinus Torvalds * demand-loading started 01.12.91 - seems it is high on the list of 91da177e4SLinus Torvalds * things wanted, and it should be easy to implement. - Linus 101da177e4SLinus Torvalds */ 111da177e4SLinus Torvalds 121da177e4SLinus Torvalds /* 131da177e4SLinus Torvalds * Ok, demand-loading was easy, shared pages a little bit tricker. Shared 141da177e4SLinus Torvalds * pages started 02.12.91, seems to work. - Linus. 151da177e4SLinus Torvalds * 161da177e4SLinus Torvalds * Tested sharing by executing about 30 /bin/sh: under the old kernel it 171da177e4SLinus Torvalds * would have taken more than the 6M I have free, but it worked well as 181da177e4SLinus Torvalds * far as I could see. 191da177e4SLinus Torvalds * 201da177e4SLinus Torvalds * Also corrected some "invalidate()"s - I wasn't doing enough of them. 211da177e4SLinus Torvalds */ 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds /* 241da177e4SLinus Torvalds * Real VM (paging to/from disk) started 18.12.91. Much more work and 251da177e4SLinus Torvalds * thought has to go into this. Oh, well.. 261da177e4SLinus Torvalds * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. 271da177e4SLinus Torvalds * Found it. Everything seems to work now. 281da177e4SLinus Torvalds * 20.12.91 - Ok, making the swap-device changeable like the root. 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * 05.04.94 - Multi-page memory management added for v1.1. 331da177e4SLinus Torvalds * Idea by Alex Bligh (alex@cconcepts.co.uk) 341da177e4SLinus Torvalds * 351da177e4SLinus Torvalds * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG 361da177e4SLinus Torvalds * (Gerhard.Wichert@pdb.siemens.de) 371da177e4SLinus Torvalds * 381da177e4SLinus Torvalds * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) 391da177e4SLinus Torvalds */ 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds #include <linux/kernel_stat.h> 421da177e4SLinus Torvalds #include <linux/mm.h> 436e84f315SIngo Molnar #include <linux/sched/mm.h> 44f7ccbae4SIngo Molnar #include <linux/sched/coredump.h> 456a3827d7SIngo Molnar #include <linux/sched/numa_balancing.h> 4629930025SIngo Molnar #include <linux/sched/task.h> 471da177e4SLinus Torvalds #include <linux/hugetlb.h> 481da177e4SLinus Torvalds #include <linux/mman.h> 491da177e4SLinus Torvalds #include <linux/swap.h> 501da177e4SLinus Torvalds #include <linux/highmem.h> 511da177e4SLinus Torvalds #include <linux/pagemap.h> 525042db43SJérôme Glisse #include <linux/memremap.h> 539a840895SHugh Dickins #include <linux/ksm.h> 541da177e4SLinus Torvalds #include <linux/rmap.h> 55b95f1b31SPaul Gortmaker #include <linux/export.h> 560ff92245SShailabh Nagar #include <linux/delayacct.h> 571da177e4SLinus Torvalds #include <linux/init.h> 5801c8f1c4SDan Williams #include <linux/pfn_t.h> 59edc79b2aSPeter Zijlstra #include <linux/writeback.h> 608a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 61cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 623dc14741SHugh Dickins #include <linux/kallsyms.h> 633dc14741SHugh Dickins #include <linux/swapops.h> 643dc14741SHugh Dickins #include <linux/elf.h> 655a0e3ad6STejun Heo #include <linux/gfp.h> 664daae3b4SMel Gorman #include <linux/migrate.h> 672fbc57c5SAndy Shevchenko #include <linux/string.h> 680abdd7a8SDan Williams #include <linux/dma-debug.h> 691592eef0SKirill A. Shutemov #include <linux/debugfs.h> 706b251fc9SAndrea Arcangeli #include <linux/userfaultfd_k.h> 71bc2466e4SJan Kara #include <linux/dax.h> 726b31d595SMichal Hocko #include <linux/oom.h> 731da177e4SLinus Torvalds 746952b61dSAlexey Dobriyan #include <asm/io.h> 7533a709b2SDave Hansen #include <asm/mmu_context.h> 761da177e4SLinus Torvalds #include <asm/pgalloc.h> 777c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 781da177e4SLinus Torvalds #include <asm/tlb.h> 791da177e4SLinus Torvalds #include <asm/tlbflush.h> 801da177e4SLinus Torvalds #include <asm/pgtable.h> 811da177e4SLinus Torvalds 8242b77728SJan Beulich #include "internal.h" 8342b77728SJan Beulich 8490572890SPeter Zijlstra #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 8590572890SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. 8675980e97SPeter Zijlstra #endif 8775980e97SPeter Zijlstra 88d41dee36SAndy Whitcroft #ifndef CONFIG_NEED_MULTIPLE_NODES 891da177e4SLinus Torvalds /* use the per-pgdat data instead for discontigmem - mbligh */ 901da177e4SLinus Torvalds unsigned long max_mapnr; 911da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 92166f61b9STobin C Harding 93166f61b9STobin C Harding struct page *mem_map; 941da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 951da177e4SLinus Torvalds #endif 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds /* 981da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 991da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 1001da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 1011da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 1021da177e4SLinus Torvalds * and ZONE_HIGHMEM. 1031da177e4SLinus Torvalds */ 1041da177e4SLinus Torvalds void *high_memory; 1051da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 1061da177e4SLinus Torvalds 10732a93233SIngo Molnar /* 10832a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 10932a93233SIngo Molnar * 11032a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 11132a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 11232a93233SIngo Molnar */ 11332a93233SIngo Molnar int randomize_va_space __read_mostly = 11432a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 11532a93233SIngo Molnar 1; 11632a93233SIngo Molnar #else 11732a93233SIngo Molnar 2; 11832a93233SIngo Molnar #endif 119a62eaf15SAndi Kleen 120a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 121a62eaf15SAndi Kleen { 122a62eaf15SAndi Kleen randomize_va_space = 0; 1239b41046cSOGAWA Hirofumi return 1; 124a62eaf15SAndi Kleen } 125a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 126a62eaf15SAndi Kleen 12762eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 1280b70068eSArd Biesheuvel EXPORT_SYMBOL(zero_pfn); 1290b70068eSArd Biesheuvel 130166f61b9STobin C Harding unsigned long highest_memmap_pfn __read_mostly; 131166f61b9STobin C Harding 132a13ea5b7SHugh Dickins /* 133a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 134a13ea5b7SHugh Dickins */ 135a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 136a13ea5b7SHugh Dickins { 137a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 138a13ea5b7SHugh Dickins return 0; 139a13ea5b7SHugh Dickins } 140a13ea5b7SHugh Dickins core_initcall(init_zero_pfn); 141a62eaf15SAndi Kleen 142d559db08SKAMEZAWA Hiroyuki 14334e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 14434e55232SKAMEZAWA Hiroyuki 145ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 14634e55232SKAMEZAWA Hiroyuki { 14734e55232SKAMEZAWA Hiroyuki int i; 14834e55232SKAMEZAWA Hiroyuki 14934e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 15005af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 15105af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 15205af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 15334e55232SKAMEZAWA Hiroyuki } 15434e55232SKAMEZAWA Hiroyuki } 15505af2e10SDavid Rientjes current->rss_stat.events = 0; 15634e55232SKAMEZAWA Hiroyuki } 15734e55232SKAMEZAWA Hiroyuki 15834e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 15934e55232SKAMEZAWA Hiroyuki { 16034e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 16134e55232SKAMEZAWA Hiroyuki 16234e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 16334e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 16434e55232SKAMEZAWA Hiroyuki else 16534e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 16634e55232SKAMEZAWA Hiroyuki } 16734e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 16834e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 16934e55232SKAMEZAWA Hiroyuki 17034e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 17134e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 17234e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 17334e55232SKAMEZAWA Hiroyuki { 17434e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 17534e55232SKAMEZAWA Hiroyuki return; 17634e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 177ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 17834e55232SKAMEZAWA Hiroyuki } 1799547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 18034e55232SKAMEZAWA Hiroyuki 18134e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 18234e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 18334e55232SKAMEZAWA Hiroyuki 18434e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 18534e55232SKAMEZAWA Hiroyuki { 18634e55232SKAMEZAWA Hiroyuki } 18734e55232SKAMEZAWA Hiroyuki 1889547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 1899547d01bSPeter Zijlstra 1909547d01bSPeter Zijlstra #ifdef HAVE_GENERIC_MMU_GATHER 1919547d01bSPeter Zijlstra 192ca1d6c7dSNicholas Krause static bool tlb_next_batch(struct mmu_gather *tlb) 1939547d01bSPeter Zijlstra { 1949547d01bSPeter Zijlstra struct mmu_gather_batch *batch; 1959547d01bSPeter Zijlstra 1969547d01bSPeter Zijlstra batch = tlb->active; 1979547d01bSPeter Zijlstra if (batch->next) { 1989547d01bSPeter Zijlstra tlb->active = batch->next; 199ca1d6c7dSNicholas Krause return true; 2009547d01bSPeter Zijlstra } 2019547d01bSPeter Zijlstra 20253a59fc6SMichal Hocko if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) 203ca1d6c7dSNicholas Krause return false; 20453a59fc6SMichal Hocko 2059547d01bSPeter Zijlstra batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); 2069547d01bSPeter Zijlstra if (!batch) 207ca1d6c7dSNicholas Krause return false; 2089547d01bSPeter Zijlstra 20953a59fc6SMichal Hocko tlb->batch_count++; 2109547d01bSPeter Zijlstra batch->next = NULL; 2119547d01bSPeter Zijlstra batch->nr = 0; 2129547d01bSPeter Zijlstra batch->max = MAX_GATHER_BATCH; 2139547d01bSPeter Zijlstra 2149547d01bSPeter Zijlstra tlb->active->next = batch; 2159547d01bSPeter Zijlstra tlb->active = batch; 2169547d01bSPeter Zijlstra 217ca1d6c7dSNicholas Krause return true; 2189547d01bSPeter Zijlstra } 2199547d01bSPeter Zijlstra 22056236a59SMinchan Kim void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, 22156236a59SMinchan Kim unsigned long start, unsigned long end) 2229547d01bSPeter Zijlstra { 2239547d01bSPeter Zijlstra tlb->mm = mm; 2249547d01bSPeter Zijlstra 2252b047252SLinus Torvalds /* Is it from 0 to ~0? */ 2262b047252SLinus Torvalds tlb->fullmm = !(start | (end+1)); 2271de14c3cSDave Hansen tlb->need_flush_all = 0; 2289547d01bSPeter Zijlstra tlb->local.next = NULL; 2299547d01bSPeter Zijlstra tlb->local.nr = 0; 2309547d01bSPeter Zijlstra tlb->local.max = ARRAY_SIZE(tlb->__pages); 2319547d01bSPeter Zijlstra tlb->active = &tlb->local; 23253a59fc6SMichal Hocko tlb->batch_count = 0; 2339547d01bSPeter Zijlstra 2349547d01bSPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 2359547d01bSPeter Zijlstra tlb->batch = NULL; 23634e55232SKAMEZAWA Hiroyuki #endif 237e77b0852SAneesh Kumar K.V tlb->page_size = 0; 238fb7332a9SWill Deacon 239fb7332a9SWill Deacon __tlb_reset_range(tlb); 2409547d01bSPeter Zijlstra } 2419547d01bSPeter Zijlstra 2421cf35d47SLinus Torvalds static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) 2439547d01bSPeter Zijlstra { 244721c21c1SWill Deacon if (!tlb->end) 245721c21c1SWill Deacon return; 246721c21c1SWill Deacon 2479547d01bSPeter Zijlstra tlb_flush(tlb); 24834ee645eSJoerg Roedel mmu_notifier_invalidate_range(tlb->mm, tlb->start, tlb->end); 2499547d01bSPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 2509547d01bSPeter Zijlstra tlb_table_flush(tlb); 2519547d01bSPeter Zijlstra #endif 252fb7332a9SWill Deacon __tlb_reset_range(tlb); 2531cf35d47SLinus Torvalds } 2541cf35d47SLinus Torvalds 2551cf35d47SLinus Torvalds static void tlb_flush_mmu_free(struct mmu_gather *tlb) 2561cf35d47SLinus Torvalds { 2571cf35d47SLinus Torvalds struct mmu_gather_batch *batch; 2589547d01bSPeter Zijlstra 259721c21c1SWill Deacon for (batch = &tlb->local; batch && batch->nr; batch = batch->next) { 2609547d01bSPeter Zijlstra free_pages_and_swap_cache(batch->pages, batch->nr); 2619547d01bSPeter Zijlstra batch->nr = 0; 2629547d01bSPeter Zijlstra } 2639547d01bSPeter Zijlstra tlb->active = &tlb->local; 2649547d01bSPeter Zijlstra } 2659547d01bSPeter Zijlstra 2661cf35d47SLinus Torvalds void tlb_flush_mmu(struct mmu_gather *tlb) 2671cf35d47SLinus Torvalds { 2681cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 2691cf35d47SLinus Torvalds tlb_flush_mmu_free(tlb); 2701cf35d47SLinus Torvalds } 2711cf35d47SLinus Torvalds 2729547d01bSPeter Zijlstra /* tlb_finish_mmu 2739547d01bSPeter Zijlstra * Called at the end of the shootdown operation to free up any resources 2749547d01bSPeter Zijlstra * that were required. 2759547d01bSPeter Zijlstra */ 27656236a59SMinchan Kim void arch_tlb_finish_mmu(struct mmu_gather *tlb, 27799baac21SMinchan Kim unsigned long start, unsigned long end, bool force) 2789547d01bSPeter Zijlstra { 2799547d01bSPeter Zijlstra struct mmu_gather_batch *batch, *next; 2809547d01bSPeter Zijlstra 28199baac21SMinchan Kim if (force) 28299baac21SMinchan Kim __tlb_adjust_range(tlb, start, end - start); 28399baac21SMinchan Kim 2849547d01bSPeter Zijlstra tlb_flush_mmu(tlb); 2859547d01bSPeter Zijlstra 2869547d01bSPeter Zijlstra /* keep the page table cache within bounds */ 2879547d01bSPeter Zijlstra check_pgt_cache(); 2889547d01bSPeter Zijlstra 2899547d01bSPeter Zijlstra for (batch = tlb->local.next; batch; batch = next) { 2909547d01bSPeter Zijlstra next = batch->next; 2919547d01bSPeter Zijlstra free_pages((unsigned long)batch, 0); 2929547d01bSPeter Zijlstra } 2939547d01bSPeter Zijlstra tlb->local.next = NULL; 2949547d01bSPeter Zijlstra } 2959547d01bSPeter Zijlstra 2969547d01bSPeter Zijlstra /* __tlb_remove_page 2979547d01bSPeter Zijlstra * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while 2989547d01bSPeter Zijlstra * handling the additional races in SMP caused by other CPUs caching valid 2999547d01bSPeter Zijlstra * mappings in their TLBs. Returns the number of free page slots left. 3009547d01bSPeter Zijlstra * When out of page slots we must call tlb_flush_mmu(). 301e9d55e15SAneesh Kumar K.V *returns true if the caller should flush. 3029547d01bSPeter Zijlstra */ 303e77b0852SAneesh Kumar K.V bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size) 3049547d01bSPeter Zijlstra { 3059547d01bSPeter Zijlstra struct mmu_gather_batch *batch; 3069547d01bSPeter Zijlstra 307fb7332a9SWill Deacon VM_BUG_ON(!tlb->end); 308692a68c1SAneesh Kumar K.V VM_WARN_ON(tlb->page_size != page_size); 309e77b0852SAneesh Kumar K.V 3109547d01bSPeter Zijlstra batch = tlb->active; 311692a68c1SAneesh Kumar K.V /* 312692a68c1SAneesh Kumar K.V * Add the page and check if we are full. If so 313692a68c1SAneesh Kumar K.V * force a flush. 314692a68c1SAneesh Kumar K.V */ 315692a68c1SAneesh Kumar K.V batch->pages[batch->nr++] = page; 3169547d01bSPeter Zijlstra if (batch->nr == batch->max) { 3179547d01bSPeter Zijlstra if (!tlb_next_batch(tlb)) 318e9d55e15SAneesh Kumar K.V return true; 3190b43c3aaSShaohua Li batch = tlb->active; 3209547d01bSPeter Zijlstra } 321309381feSSasha Levin VM_BUG_ON_PAGE(batch->nr > batch->max, page); 3229547d01bSPeter Zijlstra 323e9d55e15SAneesh Kumar K.V return false; 3249547d01bSPeter Zijlstra } 3259547d01bSPeter Zijlstra 3269547d01bSPeter Zijlstra #endif /* HAVE_GENERIC_MMU_GATHER */ 32734e55232SKAMEZAWA Hiroyuki 32826723911SPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 32926723911SPeter Zijlstra 33026723911SPeter Zijlstra /* 33126723911SPeter Zijlstra * See the comment near struct mmu_table_batch. 33226723911SPeter Zijlstra */ 33326723911SPeter Zijlstra 33426723911SPeter Zijlstra static void tlb_remove_table_smp_sync(void *arg) 33526723911SPeter Zijlstra { 33626723911SPeter Zijlstra /* Simply deliver the interrupt */ 33726723911SPeter Zijlstra } 33826723911SPeter Zijlstra 33926723911SPeter Zijlstra static void tlb_remove_table_one(void *table) 34026723911SPeter Zijlstra { 34126723911SPeter Zijlstra /* 34226723911SPeter Zijlstra * This isn't an RCU grace period and hence the page-tables cannot be 34326723911SPeter Zijlstra * assumed to be actually RCU-freed. 34426723911SPeter Zijlstra * 34526723911SPeter Zijlstra * It is however sufficient for software page-table walkers that rely on 34626723911SPeter Zijlstra * IRQ disabling. See the comment near struct mmu_table_batch. 34726723911SPeter Zijlstra */ 34826723911SPeter Zijlstra smp_call_function(tlb_remove_table_smp_sync, NULL, 1); 34926723911SPeter Zijlstra __tlb_remove_table(table); 35026723911SPeter Zijlstra } 35126723911SPeter Zijlstra 35226723911SPeter Zijlstra static void tlb_remove_table_rcu(struct rcu_head *head) 35326723911SPeter Zijlstra { 35426723911SPeter Zijlstra struct mmu_table_batch *batch; 35526723911SPeter Zijlstra int i; 35626723911SPeter Zijlstra 35726723911SPeter Zijlstra batch = container_of(head, struct mmu_table_batch, rcu); 35826723911SPeter Zijlstra 35926723911SPeter Zijlstra for (i = 0; i < batch->nr; i++) 36026723911SPeter Zijlstra __tlb_remove_table(batch->tables[i]); 36126723911SPeter Zijlstra 36226723911SPeter Zijlstra free_page((unsigned long)batch); 36326723911SPeter Zijlstra } 36426723911SPeter Zijlstra 36526723911SPeter Zijlstra void tlb_table_flush(struct mmu_gather *tlb) 36626723911SPeter Zijlstra { 36726723911SPeter Zijlstra struct mmu_table_batch **batch = &tlb->batch; 36826723911SPeter Zijlstra 36926723911SPeter Zijlstra if (*batch) { 37026723911SPeter Zijlstra call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); 37126723911SPeter Zijlstra *batch = NULL; 37226723911SPeter Zijlstra } 37326723911SPeter Zijlstra } 37426723911SPeter Zijlstra 37526723911SPeter Zijlstra void tlb_remove_table(struct mmu_gather *tlb, void *table) 37626723911SPeter Zijlstra { 37726723911SPeter Zijlstra struct mmu_table_batch **batch = &tlb->batch; 37826723911SPeter Zijlstra 37926723911SPeter Zijlstra /* 38026723911SPeter Zijlstra * When there's less then two users of this mm there cannot be a 38126723911SPeter Zijlstra * concurrent page-table walk. 38226723911SPeter Zijlstra */ 38326723911SPeter Zijlstra if (atomic_read(&tlb->mm->mm_users) < 2) { 38426723911SPeter Zijlstra __tlb_remove_table(table); 38526723911SPeter Zijlstra return; 38626723911SPeter Zijlstra } 38726723911SPeter Zijlstra 38826723911SPeter Zijlstra if (*batch == NULL) { 38926723911SPeter Zijlstra *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); 39026723911SPeter Zijlstra if (*batch == NULL) { 39126723911SPeter Zijlstra tlb_remove_table_one(table); 39226723911SPeter Zijlstra return; 39326723911SPeter Zijlstra } 39426723911SPeter Zijlstra (*batch)->nr = 0; 39526723911SPeter Zijlstra } 39626723911SPeter Zijlstra (*batch)->tables[(*batch)->nr++] = table; 39726723911SPeter Zijlstra if ((*batch)->nr == MAX_TABLE_BATCH) 39826723911SPeter Zijlstra tlb_table_flush(tlb); 39926723911SPeter Zijlstra } 40026723911SPeter Zijlstra 4019547d01bSPeter Zijlstra #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ 40226723911SPeter Zijlstra 403ef549e13SMike Rapoport /** 404ef549e13SMike Rapoport * tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down 405ef549e13SMike Rapoport * @tlb: the mmu_gather structure to initialize 406ef549e13SMike Rapoport * @mm: the mm_struct of the target address space 407ef549e13SMike Rapoport * @start: start of the region that will be removed from the page-table 408ef549e13SMike Rapoport * @end: end of the region that will be removed from the page-table 409ef549e13SMike Rapoport * 41056236a59SMinchan Kim * Called to initialize an (on-stack) mmu_gather structure for page-table 411ef549e13SMike Rapoport * tear-down from @mm. The @start and @end are set to 0 and -1 412ef549e13SMike Rapoport * respectively when @mm is without users and we're going to destroy 413ef549e13SMike Rapoport * the full address space (exit/execve). 41456236a59SMinchan Kim */ 41556236a59SMinchan Kim void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, 41656236a59SMinchan Kim unsigned long start, unsigned long end) 41756236a59SMinchan Kim { 41856236a59SMinchan Kim arch_tlb_gather_mmu(tlb, mm, start, end); 41999baac21SMinchan Kim inc_tlb_flush_pending(tlb->mm); 42056236a59SMinchan Kim } 42156236a59SMinchan Kim 42256236a59SMinchan Kim void tlb_finish_mmu(struct mmu_gather *tlb, 42356236a59SMinchan Kim unsigned long start, unsigned long end) 42456236a59SMinchan Kim { 42599baac21SMinchan Kim /* 42699baac21SMinchan Kim * If there are parallel threads are doing PTE changes on same range 42799baac21SMinchan Kim * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB 42899baac21SMinchan Kim * flush by batching, a thread has stable TLB entry can fail to flush 42999baac21SMinchan Kim * the TLB by observing pte_none|!pte_dirty, for example so flush TLB 43099baac21SMinchan Kim * forcefully if we detect parallel PTE batching threads. 43199baac21SMinchan Kim */ 43299baac21SMinchan Kim bool force = mm_tlb_flush_nested(tlb->mm); 43399baac21SMinchan Kim 43499baac21SMinchan Kim arch_tlb_finish_mmu(tlb, start, end, force); 43599baac21SMinchan Kim dec_tlb_flush_pending(tlb->mm); 43656236a59SMinchan Kim } 43756236a59SMinchan Kim 4381da177e4SLinus Torvalds /* 4391da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 4401da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 4411da177e4SLinus Torvalds */ 4429e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 4439e1b32caSBenjamin Herrenschmidt unsigned long addr) 4441da177e4SLinus Torvalds { 4452f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 4461da177e4SLinus Torvalds pmd_clear(pmd); 4479e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 448c4812909SKirill A. Shutemov mm_dec_nr_ptes(tlb->mm); 4491da177e4SLinus Torvalds } 4501da177e4SLinus Torvalds 451e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 452e0da382cSHugh Dickins unsigned long addr, unsigned long end, 453e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 4541da177e4SLinus Torvalds { 4551da177e4SLinus Torvalds pmd_t *pmd; 4561da177e4SLinus Torvalds unsigned long next; 457e0da382cSHugh Dickins unsigned long start; 4581da177e4SLinus Torvalds 459e0da382cSHugh Dickins start = addr; 4601da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 4611da177e4SLinus Torvalds do { 4621da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 4631da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 4641da177e4SLinus Torvalds continue; 4659e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 4661da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 4671da177e4SLinus Torvalds 468e0da382cSHugh Dickins start &= PUD_MASK; 469e0da382cSHugh Dickins if (start < floor) 470e0da382cSHugh Dickins return; 471e0da382cSHugh Dickins if (ceiling) { 472e0da382cSHugh Dickins ceiling &= PUD_MASK; 473e0da382cSHugh Dickins if (!ceiling) 474e0da382cSHugh Dickins return; 4751da177e4SLinus Torvalds } 476e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 477e0da382cSHugh Dickins return; 478e0da382cSHugh Dickins 479e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 480e0da382cSHugh Dickins pud_clear(pud); 4819e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 482dc6c9a35SKirill A. Shutemov mm_dec_nr_pmds(tlb->mm); 4831da177e4SLinus Torvalds } 4841da177e4SLinus Torvalds 485c2febafcSKirill A. Shutemov static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, 486e0da382cSHugh Dickins unsigned long addr, unsigned long end, 487e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 4881da177e4SLinus Torvalds { 4891da177e4SLinus Torvalds pud_t *pud; 4901da177e4SLinus Torvalds unsigned long next; 491e0da382cSHugh Dickins unsigned long start; 4921da177e4SLinus Torvalds 493e0da382cSHugh Dickins start = addr; 494c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 4951da177e4SLinus Torvalds do { 4961da177e4SLinus Torvalds next = pud_addr_end(addr, end); 4971da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 4981da177e4SLinus Torvalds continue; 499e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 5001da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 5011da177e4SLinus Torvalds 502c2febafcSKirill A. Shutemov start &= P4D_MASK; 503c2febafcSKirill A. Shutemov if (start < floor) 504c2febafcSKirill A. Shutemov return; 505c2febafcSKirill A. Shutemov if (ceiling) { 506c2febafcSKirill A. Shutemov ceiling &= P4D_MASK; 507c2febafcSKirill A. Shutemov if (!ceiling) 508c2febafcSKirill A. Shutemov return; 509c2febafcSKirill A. Shutemov } 510c2febafcSKirill A. Shutemov if (end - 1 > ceiling - 1) 511c2febafcSKirill A. Shutemov return; 512c2febafcSKirill A. Shutemov 513c2febafcSKirill A. Shutemov pud = pud_offset(p4d, start); 514c2febafcSKirill A. Shutemov p4d_clear(p4d); 515c2febafcSKirill A. Shutemov pud_free_tlb(tlb, pud, start); 516b4e98d9aSKirill A. Shutemov mm_dec_nr_puds(tlb->mm); 517c2febafcSKirill A. Shutemov } 518c2febafcSKirill A. Shutemov 519c2febafcSKirill A. Shutemov static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, 520c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 521c2febafcSKirill A. Shutemov unsigned long floor, unsigned long ceiling) 522c2febafcSKirill A. Shutemov { 523c2febafcSKirill A. Shutemov p4d_t *p4d; 524c2febafcSKirill A. Shutemov unsigned long next; 525c2febafcSKirill A. Shutemov unsigned long start; 526c2febafcSKirill A. Shutemov 527c2febafcSKirill A. Shutemov start = addr; 528c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 529c2febafcSKirill A. Shutemov do { 530c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 531c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 532c2febafcSKirill A. Shutemov continue; 533c2febafcSKirill A. Shutemov free_pud_range(tlb, p4d, addr, next, floor, ceiling); 534c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 535c2febafcSKirill A. Shutemov 536e0da382cSHugh Dickins start &= PGDIR_MASK; 537e0da382cSHugh Dickins if (start < floor) 538e0da382cSHugh Dickins return; 539e0da382cSHugh Dickins if (ceiling) { 540e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 541e0da382cSHugh Dickins if (!ceiling) 542e0da382cSHugh Dickins return; 5431da177e4SLinus Torvalds } 544e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 545e0da382cSHugh Dickins return; 546e0da382cSHugh Dickins 547c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, start); 548e0da382cSHugh Dickins pgd_clear(pgd); 549c2febafcSKirill A. Shutemov p4d_free_tlb(tlb, p4d, start); 5501da177e4SLinus Torvalds } 5511da177e4SLinus Torvalds 5521da177e4SLinus Torvalds /* 553e0da382cSHugh Dickins * This function frees user-level page tables of a process. 5541da177e4SLinus Torvalds */ 55542b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 556e0da382cSHugh Dickins unsigned long addr, unsigned long end, 557e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 5581da177e4SLinus Torvalds { 5591da177e4SLinus Torvalds pgd_t *pgd; 5601da177e4SLinus Torvalds unsigned long next; 5611da177e4SLinus Torvalds 562e0da382cSHugh Dickins /* 563e0da382cSHugh Dickins * The next few lines have given us lots of grief... 564e0da382cSHugh Dickins * 565e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 566e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 567e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 568e0da382cSHugh Dickins * 569e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 570e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 571e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 572e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 573e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 574e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 575e0da382cSHugh Dickins * that end 0 case should be mythical). 576e0da382cSHugh Dickins * 577e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 578e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 579e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 580e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 581e0da382cSHugh Dickins * 582e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 583e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 584e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 585e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 586e0da382cSHugh Dickins */ 587e0da382cSHugh Dickins 588e0da382cSHugh Dickins addr &= PMD_MASK; 589e0da382cSHugh Dickins if (addr < floor) { 590e0da382cSHugh Dickins addr += PMD_SIZE; 591e0da382cSHugh Dickins if (!addr) 592e0da382cSHugh Dickins return; 593e0da382cSHugh Dickins } 594e0da382cSHugh Dickins if (ceiling) { 595e0da382cSHugh Dickins ceiling &= PMD_MASK; 596e0da382cSHugh Dickins if (!ceiling) 597e0da382cSHugh Dickins return; 598e0da382cSHugh Dickins } 599e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 600e0da382cSHugh Dickins end -= PMD_SIZE; 601e0da382cSHugh Dickins if (addr > end - 1) 602e0da382cSHugh Dickins return; 60307e32661SAneesh Kumar K.V /* 60407e32661SAneesh Kumar K.V * We add page table cache pages with PAGE_SIZE, 60507e32661SAneesh Kumar K.V * (see pte_free_tlb()), flush the tlb if we need 60607e32661SAneesh Kumar K.V */ 60707e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, PAGE_SIZE); 60842b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 6091da177e4SLinus Torvalds do { 6101da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 6111da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 6121da177e4SLinus Torvalds continue; 613c2febafcSKirill A. Shutemov free_p4d_range(tlb, pgd, addr, next, floor, ceiling); 6141da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 615e0da382cSHugh Dickins } 616e0da382cSHugh Dickins 61742b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 618e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 619e0da382cSHugh Dickins { 620e0da382cSHugh Dickins while (vma) { 621e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 622e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 623e0da382cSHugh Dickins 6248f4f8c16SHugh Dickins /* 62525d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 62625d9e2d1Snpiggin@suse.de * pgtables 6278f4f8c16SHugh Dickins */ 6285beb4930SRik van Riel unlink_anon_vmas(vma); 6298f4f8c16SHugh Dickins unlink_file_vma(vma); 6308f4f8c16SHugh Dickins 6319da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 6323bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 6333bf5ee95SHugh Dickins floor, next ? next->vm_start : ceiling); 6343bf5ee95SHugh Dickins } else { 6353bf5ee95SHugh Dickins /* 6363bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 6373bf5ee95SHugh Dickins */ 6383bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 6394866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 640e0da382cSHugh Dickins vma = next; 641e0da382cSHugh Dickins next = vma->vm_next; 6425beb4930SRik van Riel unlink_anon_vmas(vma); 6438f4f8c16SHugh Dickins unlink_file_vma(vma); 644e0da382cSHugh Dickins } 6453bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 646e0da382cSHugh Dickins floor, next ? next->vm_start : ceiling); 6473bf5ee95SHugh Dickins } 648e0da382cSHugh Dickins vma = next; 649e0da382cSHugh Dickins } 6501da177e4SLinus Torvalds } 6511da177e4SLinus Torvalds 6523ed3a4f0SKirill A. Shutemov int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) 6531da177e4SLinus Torvalds { 654c4088ebdSKirill A. Shutemov spinlock_t *ptl; 6552f569afdSMartin Schwidefsky pgtable_t new = pte_alloc_one(mm, address); 6561da177e4SLinus Torvalds if (!new) 6571bb3630eSHugh Dickins return -ENOMEM; 6581bb3630eSHugh Dickins 659362a61adSNick Piggin /* 660362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 661362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 662362a61adSNick Piggin * put into page tables. 663362a61adSNick Piggin * 664362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 665362a61adSNick Piggin * table walking code (when walking the page table without locking; 666362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 667362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 668362a61adSNick Piggin * being the notable exception) will already guarantee loads are 669362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 670362a61adSNick Piggin * smp_read_barrier_depends() barriers in page table walking code. 671362a61adSNick Piggin */ 672362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 673362a61adSNick Piggin 674c4088ebdSKirill A. Shutemov ptl = pmd_lock(mm, pmd); 6758ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 676c4812909SKirill A. Shutemov mm_inc_nr_ptes(mm); 6771da177e4SLinus Torvalds pmd_populate(mm, pmd, new); 6782f569afdSMartin Schwidefsky new = NULL; 6794b471e88SKirill A. Shutemov } 680c4088ebdSKirill A. Shutemov spin_unlock(ptl); 6812f569afdSMartin Schwidefsky if (new) 6822f569afdSMartin Schwidefsky pte_free(mm, new); 6831bb3630eSHugh Dickins return 0; 6841da177e4SLinus Torvalds } 6851da177e4SLinus Torvalds 6861bb3630eSHugh Dickins int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) 6871da177e4SLinus Torvalds { 6881bb3630eSHugh Dickins pte_t *new = pte_alloc_one_kernel(&init_mm, address); 6891da177e4SLinus Torvalds if (!new) 6901bb3630eSHugh Dickins return -ENOMEM; 6911da177e4SLinus Torvalds 692362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 693362a61adSNick Piggin 694872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 6958ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 696872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 6972f569afdSMartin Schwidefsky new = NULL; 6984b471e88SKirill A. Shutemov } 699872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 7002f569afdSMartin Schwidefsky if (new) 7012f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 7021bb3630eSHugh Dickins return 0; 7031da177e4SLinus Torvalds } 7041da177e4SLinus Torvalds 705d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 706ae859762SHugh Dickins { 707d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 708d559db08SKAMEZAWA Hiroyuki } 709d559db08SKAMEZAWA Hiroyuki 710d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 711d559db08SKAMEZAWA Hiroyuki { 712d559db08SKAMEZAWA Hiroyuki int i; 713d559db08SKAMEZAWA Hiroyuki 71434e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 71505af2e10SDavid Rientjes sync_mm_rss(mm); 716d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 717d559db08SKAMEZAWA Hiroyuki if (rss[i]) 718d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 719ae859762SHugh Dickins } 720ae859762SHugh Dickins 7211da177e4SLinus Torvalds /* 7226aab341eSLinus Torvalds * This function is called to print an error when a bad pte 7236aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 7246aab341eSLinus Torvalds * a region that doesn't allow it. 725b5810039SNick Piggin * 726b5810039SNick Piggin * The calling function must still handle the error. 727b5810039SNick Piggin */ 7283dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 7293dc14741SHugh Dickins pte_t pte, struct page *page) 730b5810039SNick Piggin { 7313dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 732c2febafcSKirill A. Shutemov p4d_t *p4d = p4d_offset(pgd, addr); 733c2febafcSKirill A. Shutemov pud_t *pud = pud_offset(p4d, addr); 7343dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 7353dc14741SHugh Dickins struct address_space *mapping; 7363dc14741SHugh Dickins pgoff_t index; 737d936cf9bSHugh Dickins static unsigned long resume; 738d936cf9bSHugh Dickins static unsigned long nr_shown; 739d936cf9bSHugh Dickins static unsigned long nr_unshown; 740d936cf9bSHugh Dickins 741d936cf9bSHugh Dickins /* 742d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 743d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 744d936cf9bSHugh Dickins */ 745d936cf9bSHugh Dickins if (nr_shown == 60) { 746d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 747d936cf9bSHugh Dickins nr_unshown++; 748d936cf9bSHugh Dickins return; 749d936cf9bSHugh Dickins } 750d936cf9bSHugh Dickins if (nr_unshown) { 7511170532bSJoe Perches pr_alert("BUG: Bad page map: %lu messages suppressed\n", 752d936cf9bSHugh Dickins nr_unshown); 753d936cf9bSHugh Dickins nr_unshown = 0; 754d936cf9bSHugh Dickins } 755d936cf9bSHugh Dickins nr_shown = 0; 756d936cf9bSHugh Dickins } 757d936cf9bSHugh Dickins if (nr_shown++ == 0) 758d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 7593dc14741SHugh Dickins 7603dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 7613dc14741SHugh Dickins index = linear_page_index(vma, addr); 7623dc14741SHugh Dickins 7631170532bSJoe Perches pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 7643dc14741SHugh Dickins current->comm, 7653dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 766718a3821SWu Fengguang if (page) 767f0b791a3SDave Hansen dump_page(page, "bad pte"); 7681170532bSJoe Perches pr_alert("addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", 7693dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 7703dc14741SHugh Dickins /* 7713dc14741SHugh Dickins * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y 7723dc14741SHugh Dickins */ 7732682582aSKonstantin Khlebnikov pr_alert("file:%pD fault:%pf mmap:%pf readpage:%pf\n", 7742682582aSKonstantin Khlebnikov vma->vm_file, 7752682582aSKonstantin Khlebnikov vma->vm_ops ? vma->vm_ops->fault : NULL, 7762682582aSKonstantin Khlebnikov vma->vm_file ? vma->vm_file->f_op->mmap : NULL, 7772682582aSKonstantin Khlebnikov mapping ? mapping->a_ops->readpage : NULL); 778b5810039SNick Piggin dump_stack(); 779373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 780b5810039SNick Piggin } 781b5810039SNick Piggin 782b5810039SNick Piggin /* 7837e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 7846aab341eSLinus Torvalds * 7857e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 7867e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 7877e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 788b379d790SJared Hulbert * 7897e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 7907e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 7917e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 7927e675137SNick Piggin * described below. 7937e675137SNick Piggin * 7947e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 7957e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 7967e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 7976aab341eSLinus Torvalds * 798b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 799b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 8007e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 8017e675137SNick Piggin * mapping will always honor the rule 8026aab341eSLinus Torvalds * 8036aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 8046aab341eSLinus Torvalds * 8057e675137SNick Piggin * And for normal mappings this is false. 806b379d790SJared Hulbert * 8077e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 8087e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 8097e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 8107e675137SNick Piggin * special (because none can have been COWed). 811b379d790SJared Hulbert * 812b379d790SJared Hulbert * 8137e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 8147e675137SNick Piggin * 815b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 816b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 817b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 818b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 819b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 820b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 821b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 822b379d790SJared Hulbert * 823ee498ed7SHugh Dickins */ 8247e675137SNick Piggin #ifdef __HAVE_ARCH_PTE_SPECIAL 8257e675137SNick Piggin # define HAVE_PTE_SPECIAL 1 8267e675137SNick Piggin #else 8277e675137SNick Piggin # define HAVE_PTE_SPECIAL 0 8287e675137SNick Piggin #endif 829df6ad698SJérôme Glisse struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 830df6ad698SJérôme Glisse pte_t pte, bool with_public_device) 831ee498ed7SHugh Dickins { 83222b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 8337e675137SNick Piggin 8347e675137SNick Piggin if (HAVE_PTE_SPECIAL) { 835b38af472SHugh Dickins if (likely(!pte_special(pte))) 83622b31eecSHugh Dickins goto check_pfn; 837667a0a06SDavid Vrabel if (vma->vm_ops && vma->vm_ops->find_special_page) 838667a0a06SDavid Vrabel return vma->vm_ops->find_special_page(vma, addr); 839a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 840a13ea5b7SHugh Dickins return NULL; 841df6ad698SJérôme Glisse if (is_zero_pfn(pfn)) 842df6ad698SJérôme Glisse return NULL; 843df6ad698SJérôme Glisse 844df6ad698SJérôme Glisse /* 845df6ad698SJérôme Glisse * Device public pages are special pages (they are ZONE_DEVICE 846df6ad698SJérôme Glisse * pages but different from persistent memory). They behave 847df6ad698SJérôme Glisse * allmost like normal pages. The difference is that they are 848df6ad698SJérôme Glisse * not on the lru and thus should never be involve with any- 849df6ad698SJérôme Glisse * thing that involve lru manipulation (mlock, numa balancing, 850df6ad698SJérôme Glisse * ...). 851df6ad698SJérôme Glisse * 852df6ad698SJérôme Glisse * This is why we still want to return NULL for such page from 853df6ad698SJérôme Glisse * vm_normal_page() so that we do not have to special case all 854df6ad698SJérôme Glisse * call site of vm_normal_page(). 855df6ad698SJérôme Glisse */ 8567d790d2dSReza Arbab if (likely(pfn <= highest_memmap_pfn)) { 857df6ad698SJérôme Glisse struct page *page = pfn_to_page(pfn); 858df6ad698SJérôme Glisse 859df6ad698SJérôme Glisse if (is_device_public_page(page)) { 860df6ad698SJérôme Glisse if (with_public_device) 861df6ad698SJérôme Glisse return page; 862df6ad698SJérôme Glisse return NULL; 863df6ad698SJérôme Glisse } 864df6ad698SJérôme Glisse } 86522b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 8667e675137SNick Piggin return NULL; 8677e675137SNick Piggin } 8687e675137SNick Piggin 8697e675137SNick Piggin /* !HAVE_PTE_SPECIAL case follows: */ 8707e675137SNick Piggin 871b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 872b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 873b379d790SJared Hulbert if (!pfn_valid(pfn)) 874b379d790SJared Hulbert return NULL; 875b379d790SJared Hulbert goto out; 876b379d790SJared Hulbert } else { 8777e675137SNick Piggin unsigned long off; 8787e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 8796aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 8806aab341eSLinus Torvalds return NULL; 88167121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 882fb155c16SLinus Torvalds return NULL; 8836aab341eSLinus Torvalds } 884b379d790SJared Hulbert } 8856aab341eSLinus Torvalds 886b38af472SHugh Dickins if (is_zero_pfn(pfn)) 887b38af472SHugh Dickins return NULL; 88822b31eecSHugh Dickins check_pfn: 88922b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 89022b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 89122b31eecSHugh Dickins return NULL; 89222b31eecSHugh Dickins } 8936aab341eSLinus Torvalds 8946aab341eSLinus Torvalds /* 8957e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 8967e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 8976aab341eSLinus Torvalds */ 898b379d790SJared Hulbert out: 8996aab341eSLinus Torvalds return pfn_to_page(pfn); 900ee498ed7SHugh Dickins } 901ee498ed7SHugh Dickins 90228093f9fSGerald Schaefer #ifdef CONFIG_TRANSPARENT_HUGEPAGE 90328093f9fSGerald Schaefer struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, 90428093f9fSGerald Schaefer pmd_t pmd) 90528093f9fSGerald Schaefer { 90628093f9fSGerald Schaefer unsigned long pfn = pmd_pfn(pmd); 90728093f9fSGerald Schaefer 90828093f9fSGerald Schaefer /* 90928093f9fSGerald Schaefer * There is no pmd_special() but there may be special pmds, e.g. 91028093f9fSGerald Schaefer * in a direct-access (dax) mapping, so let's just replicate the 91128093f9fSGerald Schaefer * !HAVE_PTE_SPECIAL case from vm_normal_page() here. 91228093f9fSGerald Schaefer */ 91328093f9fSGerald Schaefer if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 91428093f9fSGerald Schaefer if (vma->vm_flags & VM_MIXEDMAP) { 91528093f9fSGerald Schaefer if (!pfn_valid(pfn)) 91628093f9fSGerald Schaefer return NULL; 91728093f9fSGerald Schaefer goto out; 91828093f9fSGerald Schaefer } else { 91928093f9fSGerald Schaefer unsigned long off; 92028093f9fSGerald Schaefer off = (addr - vma->vm_start) >> PAGE_SHIFT; 92128093f9fSGerald Schaefer if (pfn == vma->vm_pgoff + off) 92228093f9fSGerald Schaefer return NULL; 92328093f9fSGerald Schaefer if (!is_cow_mapping(vma->vm_flags)) 92428093f9fSGerald Schaefer return NULL; 92528093f9fSGerald Schaefer } 92628093f9fSGerald Schaefer } 92728093f9fSGerald Schaefer 92828093f9fSGerald Schaefer if (is_zero_pfn(pfn)) 92928093f9fSGerald Schaefer return NULL; 93028093f9fSGerald Schaefer if (unlikely(pfn > highest_memmap_pfn)) 93128093f9fSGerald Schaefer return NULL; 93228093f9fSGerald Schaefer 93328093f9fSGerald Schaefer /* 93428093f9fSGerald Schaefer * NOTE! We still have PageReserved() pages in the page tables. 93528093f9fSGerald Schaefer * eg. VDSO mappings can cause them to exist. 93628093f9fSGerald Schaefer */ 93728093f9fSGerald Schaefer out: 93828093f9fSGerald Schaefer return pfn_to_page(pfn); 93928093f9fSGerald Schaefer } 94028093f9fSGerald Schaefer #endif 94128093f9fSGerald Schaefer 942ee498ed7SHugh Dickins /* 9431da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 9441da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 9451da177e4SLinus Torvalds * covered by this vma. 9461da177e4SLinus Torvalds */ 9471da177e4SLinus Torvalds 948570a335bSHugh Dickins static inline unsigned long 9491da177e4SLinus Torvalds copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 950b5810039SNick Piggin pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 9518c103762SHugh Dickins unsigned long addr, int *rss) 9521da177e4SLinus Torvalds { 953b5810039SNick Piggin unsigned long vm_flags = vma->vm_flags; 9541da177e4SLinus Torvalds pte_t pte = *src_pte; 9551da177e4SLinus Torvalds struct page *page; 9561da177e4SLinus Torvalds 9571da177e4SLinus Torvalds /* pte contains position in swap or file, so copy. */ 9581da177e4SLinus Torvalds if (unlikely(!pte_present(pte))) { 9590697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 9600697212aSChristoph Lameter 9612022b4d1SHugh Dickins if (likely(!non_swap_entry(entry))) { 962570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 963570a335bSHugh Dickins return entry.val; 964570a335bSHugh Dickins 9651da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 9661da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 9671da177e4SLinus Torvalds spin_lock(&mmlist_lock); 968f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 969f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 970f412ac08SHugh Dickins &src_mm->mmlist); 9711da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 9721da177e4SLinus Torvalds } 973b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 9742022b4d1SHugh Dickins } else if (is_migration_entry(entry)) { 9759f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 9769f9f1acdSKonstantin Khlebnikov 977eca56ff9SJerome Marchand rss[mm_counter(page)]++; 9789f9f1acdSKonstantin Khlebnikov 9799f9f1acdSKonstantin Khlebnikov if (is_write_migration_entry(entry) && 9800697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 9810697212aSChristoph Lameter /* 9829f9f1acdSKonstantin Khlebnikov * COW mappings require pages in both 9839f9f1acdSKonstantin Khlebnikov * parent and child to be set to read. 9840697212aSChristoph Lameter */ 9850697212aSChristoph Lameter make_migration_entry_read(&entry); 9860697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 987c3d16e16SCyrill Gorcunov if (pte_swp_soft_dirty(*src_pte)) 988c3d16e16SCyrill Gorcunov pte = pte_swp_mksoft_dirty(pte); 9890697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 9900697212aSChristoph Lameter } 9915042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 9925042db43SJérôme Glisse page = device_private_entry_to_page(entry); 9935042db43SJérôme Glisse 9945042db43SJérôme Glisse /* 9955042db43SJérôme Glisse * Update rss count even for unaddressable pages, as 9965042db43SJérôme Glisse * they should treated just like normal pages in this 9975042db43SJérôme Glisse * respect. 9985042db43SJérôme Glisse * 9995042db43SJérôme Glisse * We will likely want to have some new rss counters 10005042db43SJérôme Glisse * for unaddressable pages, at some point. But for now 10015042db43SJérôme Glisse * keep things as they are. 10025042db43SJérôme Glisse */ 10035042db43SJérôme Glisse get_page(page); 10045042db43SJérôme Glisse rss[mm_counter(page)]++; 10055042db43SJérôme Glisse page_dup_rmap(page, false); 10065042db43SJérôme Glisse 10075042db43SJérôme Glisse /* 10085042db43SJérôme Glisse * We do not preserve soft-dirty information, because so 10095042db43SJérôme Glisse * far, checkpoint/restore is the only feature that 10105042db43SJérôme Glisse * requires that. And checkpoint/restore does not work 10115042db43SJérôme Glisse * when a device driver is involved (you cannot easily 10125042db43SJérôme Glisse * save and restore device driver state). 10135042db43SJérôme Glisse */ 10145042db43SJérôme Glisse if (is_write_device_private_entry(entry) && 10155042db43SJérôme Glisse is_cow_mapping(vm_flags)) { 10165042db43SJérôme Glisse make_device_private_entry_read(&entry); 10175042db43SJérôme Glisse pte = swp_entry_to_pte(entry); 10185042db43SJérôme Glisse set_pte_at(src_mm, addr, src_pte, pte); 10195042db43SJérôme Glisse } 10201da177e4SLinus Torvalds } 1021ae859762SHugh Dickins goto out_set_pte; 10221da177e4SLinus Torvalds } 10231da177e4SLinus Torvalds 10241da177e4SLinus Torvalds /* 10251da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 10261da177e4SLinus Torvalds * in the parent and the child 10271da177e4SLinus Torvalds */ 102867121172SLinus Torvalds if (is_cow_mapping(vm_flags)) { 10291da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 10303dc90795SZachary Amsden pte = pte_wrprotect(pte); 10311da177e4SLinus Torvalds } 10321da177e4SLinus Torvalds 10331da177e4SLinus Torvalds /* 10341da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 10351da177e4SLinus Torvalds * the child 10361da177e4SLinus Torvalds */ 10371da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 10381da177e4SLinus Torvalds pte = pte_mkclean(pte); 10391da177e4SLinus Torvalds pte = pte_mkold(pte); 10406aab341eSLinus Torvalds 10416aab341eSLinus Torvalds page = vm_normal_page(vma, addr, pte); 10426aab341eSLinus Torvalds if (page) { 10431da177e4SLinus Torvalds get_page(page); 104453f9263bSKirill A. Shutemov page_dup_rmap(page, false); 1045eca56ff9SJerome Marchand rss[mm_counter(page)]++; 1046df6ad698SJérôme Glisse } else if (pte_devmap(pte)) { 1047df6ad698SJérôme Glisse page = pte_page(pte); 1048df6ad698SJérôme Glisse 1049df6ad698SJérôme Glisse /* 1050df6ad698SJérôme Glisse * Cache coherent device memory behave like regular page and 1051df6ad698SJérôme Glisse * not like persistent memory page. For more informations see 1052df6ad698SJérôme Glisse * MEMORY_DEVICE_CACHE_COHERENT in memory_hotplug.h 1053df6ad698SJérôme Glisse */ 1054df6ad698SJérôme Glisse if (is_device_public_page(page)) { 1055df6ad698SJérôme Glisse get_page(page); 1056df6ad698SJérôme Glisse page_dup_rmap(page, false); 1057df6ad698SJérôme Glisse rss[mm_counter(page)]++; 1058df6ad698SJérôme Glisse } 10596aab341eSLinus Torvalds } 1060ae859762SHugh Dickins 1061ae859762SHugh Dickins out_set_pte: 1062ae859762SHugh Dickins set_pte_at(dst_mm, addr, dst_pte, pte); 1063570a335bSHugh Dickins return 0; 10641da177e4SLinus Torvalds } 10651da177e4SLinus Torvalds 106621bda264SJerome Marchand static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 10671da177e4SLinus Torvalds pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 10681da177e4SLinus Torvalds unsigned long addr, unsigned long end) 10691da177e4SLinus Torvalds { 1070c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 10711da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 1072c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 1073e040f218SHugh Dickins int progress = 0; 1074d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 1075570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 10761da177e4SLinus Torvalds 10771da177e4SLinus Torvalds again: 1078d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 1079d559db08SKAMEZAWA Hiroyuki 1080c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 10811da177e4SLinus Torvalds if (!dst_pte) 10821da177e4SLinus Torvalds return -ENOMEM; 1083ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 10844c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 1085f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 1086c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 1087c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 10886606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10891da177e4SLinus Torvalds 10901da177e4SLinus Torvalds do { 10911da177e4SLinus Torvalds /* 10921da177e4SLinus Torvalds * We are holding two locks at this point - either of them 10931da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 10941da177e4SLinus Torvalds */ 1095e040f218SHugh Dickins if (progress >= 32) { 1096e040f218SHugh Dickins progress = 0; 1097e040f218SHugh Dickins if (need_resched() || 109895c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 10991da177e4SLinus Torvalds break; 1100e040f218SHugh Dickins } 11011da177e4SLinus Torvalds if (pte_none(*src_pte)) { 11021da177e4SLinus Torvalds progress++; 11031da177e4SLinus Torvalds continue; 11041da177e4SLinus Torvalds } 1105570a335bSHugh Dickins entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, 1106570a335bSHugh Dickins vma, addr, rss); 1107570a335bSHugh Dickins if (entry.val) 1108570a335bSHugh Dickins break; 11091da177e4SLinus Torvalds progress += 8; 11101da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 11111da177e4SLinus Torvalds 11126606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1113c74df32cSHugh Dickins spin_unlock(src_ptl); 1114ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 1115d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 1116c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 1117c74df32cSHugh Dickins cond_resched(); 1118570a335bSHugh Dickins 1119570a335bSHugh Dickins if (entry.val) { 1120570a335bSHugh Dickins if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) 1121570a335bSHugh Dickins return -ENOMEM; 1122570a335bSHugh Dickins progress = 0; 1123570a335bSHugh Dickins } 11241da177e4SLinus Torvalds if (addr != end) 11251da177e4SLinus Torvalds goto again; 11261da177e4SLinus Torvalds return 0; 11271da177e4SLinus Torvalds } 11281da177e4SLinus Torvalds 11291da177e4SLinus Torvalds static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 11301da177e4SLinus Torvalds pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 11311da177e4SLinus Torvalds unsigned long addr, unsigned long end) 11321da177e4SLinus Torvalds { 11331da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 11341da177e4SLinus Torvalds unsigned long next; 11351da177e4SLinus Torvalds 11361da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 11371da177e4SLinus Torvalds if (!dst_pmd) 11381da177e4SLinus Torvalds return -ENOMEM; 11391da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 11401da177e4SLinus Torvalds do { 11411da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 114284c3fc4eSZi Yan if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd) 114384c3fc4eSZi Yan || pmd_devmap(*src_pmd)) { 114471e3aac0SAndrea Arcangeli int err; 1145a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, vma); 114671e3aac0SAndrea Arcangeli err = copy_huge_pmd(dst_mm, src_mm, 114771e3aac0SAndrea Arcangeli dst_pmd, src_pmd, addr, vma); 114871e3aac0SAndrea Arcangeli if (err == -ENOMEM) 114971e3aac0SAndrea Arcangeli return -ENOMEM; 115071e3aac0SAndrea Arcangeli if (!err) 115171e3aac0SAndrea Arcangeli continue; 115271e3aac0SAndrea Arcangeli /* fall through */ 115371e3aac0SAndrea Arcangeli } 11541da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 11551da177e4SLinus Torvalds continue; 11561da177e4SLinus Torvalds if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 11571da177e4SLinus Torvalds vma, addr, next)) 11581da177e4SLinus Torvalds return -ENOMEM; 11591da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 11601da177e4SLinus Torvalds return 0; 11611da177e4SLinus Torvalds } 11621da177e4SLinus Torvalds 11631da177e4SLinus Torvalds static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1164c2febafcSKirill A. Shutemov p4d_t *dst_p4d, p4d_t *src_p4d, struct vm_area_struct *vma, 11651da177e4SLinus Torvalds unsigned long addr, unsigned long end) 11661da177e4SLinus Torvalds { 11671da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 11681da177e4SLinus Torvalds unsigned long next; 11691da177e4SLinus Torvalds 1170c2febafcSKirill A. Shutemov dst_pud = pud_alloc(dst_mm, dst_p4d, addr); 11711da177e4SLinus Torvalds if (!dst_pud) 11721da177e4SLinus Torvalds return -ENOMEM; 1173c2febafcSKirill A. Shutemov src_pud = pud_offset(src_p4d, addr); 11741da177e4SLinus Torvalds do { 11751da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1176a00cc7d9SMatthew Wilcox if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { 1177a00cc7d9SMatthew Wilcox int err; 1178a00cc7d9SMatthew Wilcox 1179a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, vma); 1180a00cc7d9SMatthew Wilcox err = copy_huge_pud(dst_mm, src_mm, 1181a00cc7d9SMatthew Wilcox dst_pud, src_pud, addr, vma); 1182a00cc7d9SMatthew Wilcox if (err == -ENOMEM) 1183a00cc7d9SMatthew Wilcox return -ENOMEM; 1184a00cc7d9SMatthew Wilcox if (!err) 1185a00cc7d9SMatthew Wilcox continue; 1186a00cc7d9SMatthew Wilcox /* fall through */ 1187a00cc7d9SMatthew Wilcox } 11881da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 11891da177e4SLinus Torvalds continue; 11901da177e4SLinus Torvalds if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 11911da177e4SLinus Torvalds vma, addr, next)) 11921da177e4SLinus Torvalds return -ENOMEM; 11931da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 11941da177e4SLinus Torvalds return 0; 11951da177e4SLinus Torvalds } 11961da177e4SLinus Torvalds 1197c2febafcSKirill A. Shutemov static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 1198c2febafcSKirill A. Shutemov pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 1199c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end) 1200c2febafcSKirill A. Shutemov { 1201c2febafcSKirill A. Shutemov p4d_t *src_p4d, *dst_p4d; 1202c2febafcSKirill A. Shutemov unsigned long next; 1203c2febafcSKirill A. Shutemov 1204c2febafcSKirill A. Shutemov dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr); 1205c2febafcSKirill A. Shutemov if (!dst_p4d) 1206c2febafcSKirill A. Shutemov return -ENOMEM; 1207c2febafcSKirill A. Shutemov src_p4d = p4d_offset(src_pgd, addr); 1208c2febafcSKirill A. Shutemov do { 1209c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1210c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(src_p4d)) 1211c2febafcSKirill A. Shutemov continue; 1212c2febafcSKirill A. Shutemov if (copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d, 1213c2febafcSKirill A. Shutemov vma, addr, next)) 1214c2febafcSKirill A. Shutemov return -ENOMEM; 1215c2febafcSKirill A. Shutemov } while (dst_p4d++, src_p4d++, addr = next, addr != end); 1216c2febafcSKirill A. Shutemov return 0; 1217c2febafcSKirill A. Shutemov } 1218c2febafcSKirill A. Shutemov 12191da177e4SLinus Torvalds int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 12201da177e4SLinus Torvalds struct vm_area_struct *vma) 12211da177e4SLinus Torvalds { 12221da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 12231da177e4SLinus Torvalds unsigned long next; 12241da177e4SLinus Torvalds unsigned long addr = vma->vm_start; 12251da177e4SLinus Torvalds unsigned long end = vma->vm_end; 12262ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 12272ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 12282ec74c3eSSagi Grimberg bool is_cow; 1229cddb8a5cSAndrea Arcangeli int ret; 12301da177e4SLinus Torvalds 1231d992895bSNick Piggin /* 1232d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 1233d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 1234d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 1235d992895bSNick Piggin * efficient than faulting. 1236d992895bSNick Piggin */ 12370661a336SKirill A. Shutemov if (!(vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && 12380661a336SKirill A. Shutemov !vma->anon_vma) 1239d992895bSNick Piggin return 0; 1240d992895bSNick Piggin 12411da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) 12421da177e4SLinus Torvalds return copy_hugetlb_page_range(dst_mm, src_mm, vma); 12431da177e4SLinus Torvalds 1244b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) { 12452ab64037Svenkatesh.pallipadi@intel.com /* 12462ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 12472ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 12482ab64037Svenkatesh.pallipadi@intel.com */ 12495180da41SSuresh Siddha ret = track_pfn_copy(vma); 12502ab64037Svenkatesh.pallipadi@intel.com if (ret) 12512ab64037Svenkatesh.pallipadi@intel.com return ret; 12522ab64037Svenkatesh.pallipadi@intel.com } 12532ab64037Svenkatesh.pallipadi@intel.com 1254cddb8a5cSAndrea Arcangeli /* 1255cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1256cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1257cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1258cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1259cddb8a5cSAndrea Arcangeli */ 12602ec74c3eSSagi Grimberg is_cow = is_cow_mapping(vma->vm_flags); 12612ec74c3eSSagi Grimberg mmun_start = addr; 12622ec74c3eSSagi Grimberg mmun_end = end; 12632ec74c3eSSagi Grimberg if (is_cow) 12642ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(src_mm, mmun_start, 12652ec74c3eSSagi Grimberg mmun_end); 1266cddb8a5cSAndrea Arcangeli 1267cddb8a5cSAndrea Arcangeli ret = 0; 12681da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 12691da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 12701da177e4SLinus Torvalds do { 12711da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 12721da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 12731da177e4SLinus Torvalds continue; 1274c2febafcSKirill A. Shutemov if (unlikely(copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd, 1275cddb8a5cSAndrea Arcangeli vma, addr, next))) { 1276cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1277cddb8a5cSAndrea Arcangeli break; 1278cddb8a5cSAndrea Arcangeli } 12791da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1280cddb8a5cSAndrea Arcangeli 12812ec74c3eSSagi Grimberg if (is_cow) 12822ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end); 1283cddb8a5cSAndrea Arcangeli return ret; 12841da177e4SLinus Torvalds } 12851da177e4SLinus Torvalds 128651c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1287b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 12881da177e4SLinus Torvalds unsigned long addr, unsigned long end, 128997a89413SPeter Zijlstra struct zap_details *details) 12901da177e4SLinus Torvalds { 1291b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1292d16dfc55SPeter Zijlstra int force_flush = 0; 1293d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 129497a89413SPeter Zijlstra spinlock_t *ptl; 12955f1a1907SSteven Rostedt pte_t *start_pte; 129697a89413SPeter Zijlstra pte_t *pte; 12978a5f14a2SKirill A. Shutemov swp_entry_t entry; 1298d559db08SKAMEZAWA Hiroyuki 129907e32661SAneesh Kumar K.V tlb_remove_check_page_size_change(tlb, PAGE_SIZE); 1300d16dfc55SPeter Zijlstra again: 1301e303297eSPeter Zijlstra init_rss_vec(rss); 13025f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 13035f1a1907SSteven Rostedt pte = start_pte; 13043ea27719SMel Gorman flush_tlb_batched_pending(mm); 13056606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 13061da177e4SLinus Torvalds do { 13071da177e4SLinus Torvalds pte_t ptent = *pte; 1308166f61b9STobin C Harding if (pte_none(ptent)) 13091da177e4SLinus Torvalds continue; 131051c6f666SRobin Holt 13116f5e6b9eSHugh Dickins if (pte_present(ptent)) { 13126f5e6b9eSHugh Dickins struct page *page; 13136f5e6b9eSHugh Dickins 1314df6ad698SJérôme Glisse page = _vm_normal_page(vma, addr, ptent, true); 13151da177e4SLinus Torvalds if (unlikely(details) && page) { 13161da177e4SLinus Torvalds /* 13171da177e4SLinus Torvalds * unmap_shared_mapping_pages() wants to 13181da177e4SLinus Torvalds * invalidate cache without truncating: 13191da177e4SLinus Torvalds * unmap shared but keep private pages. 13201da177e4SLinus Torvalds */ 13211da177e4SLinus Torvalds if (details->check_mapping && 1322800d8c63SKirill A. Shutemov details->check_mapping != page_rmapping(page)) 13231da177e4SLinus Torvalds continue; 13241da177e4SLinus Torvalds } 1325b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1326a600388dSZachary Amsden tlb->fullmm); 13271da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 13281da177e4SLinus Torvalds if (unlikely(!page)) 13291da177e4SLinus Torvalds continue; 1330eca56ff9SJerome Marchand 1331eca56ff9SJerome Marchand if (!PageAnon(page)) { 13321cf35d47SLinus Torvalds if (pte_dirty(ptent)) { 13331cf35d47SLinus Torvalds force_flush = 1; 13346237bcd9SHugh Dickins set_page_dirty(page); 13351cf35d47SLinus Torvalds } 13364917e5d0SJohannes Weiner if (pte_young(ptent) && 133764363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1338bf3f3bc5SNick Piggin mark_page_accessed(page); 13396237bcd9SHugh Dickins } 1340eca56ff9SJerome Marchand rss[mm_counter(page)]--; 1341d281ee61SKirill A. Shutemov page_remove_rmap(page, false); 13423dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 13433dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1344e9d55e15SAneesh Kumar K.V if (unlikely(__tlb_remove_page(tlb, page))) { 13451cf35d47SLinus Torvalds force_flush = 1; 1346ce9ec37bSWill Deacon addr += PAGE_SIZE; 1347d16dfc55SPeter Zijlstra break; 13481cf35d47SLinus Torvalds } 13491da177e4SLinus Torvalds continue; 13501da177e4SLinus Torvalds } 13515042db43SJérôme Glisse 13525042db43SJérôme Glisse entry = pte_to_swp_entry(ptent); 13535042db43SJérôme Glisse if (non_swap_entry(entry) && is_device_private_entry(entry)) { 13545042db43SJérôme Glisse struct page *page = device_private_entry_to_page(entry); 13555042db43SJérôme Glisse 13565042db43SJérôme Glisse if (unlikely(details && details->check_mapping)) { 13575042db43SJérôme Glisse /* 13585042db43SJérôme Glisse * unmap_shared_mapping_pages() wants to 13595042db43SJérôme Glisse * invalidate cache without truncating: 13605042db43SJérôme Glisse * unmap shared but keep private pages. 13615042db43SJérôme Glisse */ 13625042db43SJérôme Glisse if (details->check_mapping != 13635042db43SJérôme Glisse page_rmapping(page)) 13645042db43SJérôme Glisse continue; 13655042db43SJérôme Glisse } 13665042db43SJérôme Glisse 13675042db43SJérôme Glisse pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 13685042db43SJérôme Glisse rss[mm_counter(page)]--; 13695042db43SJérôme Glisse page_remove_rmap(page, false); 13705042db43SJérôme Glisse put_page(page); 13715042db43SJérôme Glisse continue; 13725042db43SJérôme Glisse } 13735042db43SJérôme Glisse 13743e8715fdSKirill A. Shutemov /* If details->check_mapping, we leave swap entries. */ 13753e8715fdSKirill A. Shutemov if (unlikely(details)) 13761da177e4SLinus Torvalds continue; 1377b084d435SKAMEZAWA Hiroyuki 13788a5f14a2SKirill A. Shutemov entry = pte_to_swp_entry(ptent); 1379b084d435SKAMEZAWA Hiroyuki if (!non_swap_entry(entry)) 1380b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 13819f9f1acdSKonstantin Khlebnikov else if (is_migration_entry(entry)) { 13829f9f1acdSKonstantin Khlebnikov struct page *page; 13839f9f1acdSKonstantin Khlebnikov 13849f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 1385eca56ff9SJerome Marchand rss[mm_counter(page)]--; 13869f9f1acdSKonstantin Khlebnikov } 1387b084d435SKAMEZAWA Hiroyuki if (unlikely(!free_swap_and_cache(entry))) 13882509ef26SHugh Dickins print_bad_pte(vma, addr, ptent, NULL); 13899888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 139097a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1391ae859762SHugh Dickins 1392d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 13936606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 139451c6f666SRobin Holt 13951cf35d47SLinus Torvalds /* Do the actual TLB flush before dropping ptl */ 1396fb7332a9SWill Deacon if (force_flush) 13971cf35d47SLinus Torvalds tlb_flush_mmu_tlbonly(tlb); 13981cf35d47SLinus Torvalds pte_unmap_unlock(start_pte, ptl); 13991cf35d47SLinus Torvalds 14001cf35d47SLinus Torvalds /* 14011cf35d47SLinus Torvalds * If we forced a TLB flush (either due to running out of 14021cf35d47SLinus Torvalds * batch buffers or because we needed to flush dirty TLB 14031cf35d47SLinus Torvalds * entries before releasing the ptl), free the batched 14041cf35d47SLinus Torvalds * memory too. Restart if we didn't do everything. 14051cf35d47SLinus Torvalds */ 14061cf35d47SLinus Torvalds if (force_flush) { 14071cf35d47SLinus Torvalds force_flush = 0; 14081cf35d47SLinus Torvalds tlb_flush_mmu_free(tlb); 14092b047252SLinus Torvalds if (addr != end) 1410d16dfc55SPeter Zijlstra goto again; 1411d16dfc55SPeter Zijlstra } 1412d16dfc55SPeter Zijlstra 141351c6f666SRobin Holt return addr; 14141da177e4SLinus Torvalds } 14151da177e4SLinus Torvalds 141651c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1417b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 14181da177e4SLinus Torvalds unsigned long addr, unsigned long end, 141997a89413SPeter Zijlstra struct zap_details *details) 14201da177e4SLinus Torvalds { 14211da177e4SLinus Torvalds pmd_t *pmd; 14221da177e4SLinus Torvalds unsigned long next; 14231da177e4SLinus Torvalds 14241da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 14251da177e4SLinus Torvalds do { 14261da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 142784c3fc4eSZi Yan if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { 142814d1a55cSAndrea Arcangeli if (next - addr != HPAGE_PMD_SIZE) { 142968428398SHugh Dickins VM_BUG_ON_VMA(vma_is_anonymous(vma) && 143068428398SHugh Dickins !rwsem_is_locked(&tlb->mm->mmap_sem), vma); 1431fd60775aSDavid Rientjes __split_huge_pmd(vma, pmd, addr, false, NULL); 1432f21760b1SShaohua Li } else if (zap_huge_pmd(tlb, vma, pmd, addr)) 14331a5a9906SAndrea Arcangeli goto next; 143471e3aac0SAndrea Arcangeli /* fall through */ 143571e3aac0SAndrea Arcangeli } 14361a5a9906SAndrea Arcangeli /* 14371a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 14381a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 14391a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 14401a5a9906SAndrea Arcangeli * because MADV_DONTNEED holds the mmap_sem in read 14411a5a9906SAndrea Arcangeli * mode. 14421a5a9906SAndrea Arcangeli */ 14431a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 14441a5a9906SAndrea Arcangeli goto next; 144597a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 14461a5a9906SAndrea Arcangeli next: 144797a89413SPeter Zijlstra cond_resched(); 144897a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 144951c6f666SRobin Holt 145051c6f666SRobin Holt return addr; 14511da177e4SLinus Torvalds } 14521da177e4SLinus Torvalds 145351c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1454c2febafcSKirill A. Shutemov struct vm_area_struct *vma, p4d_t *p4d, 14551da177e4SLinus Torvalds unsigned long addr, unsigned long end, 145697a89413SPeter Zijlstra struct zap_details *details) 14571da177e4SLinus Torvalds { 14581da177e4SLinus Torvalds pud_t *pud; 14591da177e4SLinus Torvalds unsigned long next; 14601da177e4SLinus Torvalds 1461c2febafcSKirill A. Shutemov pud = pud_offset(p4d, addr); 14621da177e4SLinus Torvalds do { 14631da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1464a00cc7d9SMatthew Wilcox if (pud_trans_huge(*pud) || pud_devmap(*pud)) { 1465a00cc7d9SMatthew Wilcox if (next - addr != HPAGE_PUD_SIZE) { 1466a00cc7d9SMatthew Wilcox VM_BUG_ON_VMA(!rwsem_is_locked(&tlb->mm->mmap_sem), vma); 1467a00cc7d9SMatthew Wilcox split_huge_pud(vma, pud, addr); 1468a00cc7d9SMatthew Wilcox } else if (zap_huge_pud(tlb, vma, pud, addr)) 1469a00cc7d9SMatthew Wilcox goto next; 1470a00cc7d9SMatthew Wilcox /* fall through */ 1471a00cc7d9SMatthew Wilcox } 147297a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 14731da177e4SLinus Torvalds continue; 147497a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 1475a00cc7d9SMatthew Wilcox next: 1476a00cc7d9SMatthew Wilcox cond_resched(); 147797a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 147851c6f666SRobin Holt 147951c6f666SRobin Holt return addr; 14801da177e4SLinus Torvalds } 14811da177e4SLinus Torvalds 1482c2febafcSKirill A. Shutemov static inline unsigned long zap_p4d_range(struct mmu_gather *tlb, 1483c2febafcSKirill A. Shutemov struct vm_area_struct *vma, pgd_t *pgd, 1484c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 1485c2febafcSKirill A. Shutemov struct zap_details *details) 1486c2febafcSKirill A. Shutemov { 1487c2febafcSKirill A. Shutemov p4d_t *p4d; 1488c2febafcSKirill A. Shutemov unsigned long next; 1489c2febafcSKirill A. Shutemov 1490c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, addr); 1491c2febafcSKirill A. Shutemov do { 1492c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 1493c2febafcSKirill A. Shutemov if (p4d_none_or_clear_bad(p4d)) 1494c2febafcSKirill A. Shutemov continue; 1495c2febafcSKirill A. Shutemov next = zap_pud_range(tlb, vma, p4d, addr, next, details); 1496c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 1497c2febafcSKirill A. Shutemov 1498c2febafcSKirill A. Shutemov return addr; 1499c2febafcSKirill A. Shutemov } 1500c2febafcSKirill A. Shutemov 1501aac45363SMichal Hocko void unmap_page_range(struct mmu_gather *tlb, 150251c6f666SRobin Holt struct vm_area_struct *vma, 15031da177e4SLinus Torvalds unsigned long addr, unsigned long end, 150497a89413SPeter Zijlstra struct zap_details *details) 15051da177e4SLinus Torvalds { 15061da177e4SLinus Torvalds pgd_t *pgd; 15071da177e4SLinus Torvalds unsigned long next; 15081da177e4SLinus Torvalds 15091da177e4SLinus Torvalds BUG_ON(addr >= end); 15101da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 15111da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 15121da177e4SLinus Torvalds do { 15131da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 151497a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 15151da177e4SLinus Torvalds continue; 1516c2febafcSKirill A. Shutemov next = zap_p4d_range(tlb, vma, pgd, addr, next, details); 151797a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 15181da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 15191da177e4SLinus Torvalds } 15201da177e4SLinus Torvalds 1521f5cc4eefSAl Viro 1522f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 15231da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 15244f74d2c8SLinus Torvalds unsigned long end_addr, 15251da177e4SLinus Torvalds struct zap_details *details) 15261da177e4SLinus Torvalds { 1527f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 15281da177e4SLinus Torvalds unsigned long end; 15291da177e4SLinus Torvalds 15301da177e4SLinus Torvalds if (start >= vma->vm_end) 1531f5cc4eefSAl Viro return; 15321da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 15331da177e4SLinus Torvalds if (end <= vma->vm_start) 1534f5cc4eefSAl Viro return; 15351da177e4SLinus Torvalds 1536cbc91f71SSrikar Dronamraju if (vma->vm_file) 1537cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1538cbc91f71SSrikar Dronamraju 1539b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 15405180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 15412ab64037Svenkatesh.pallipadi@intel.com 15428b2a1238SAl Viro if (start != end) { 154351c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1544a137e1ccSAndi Kleen /* 1545a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1546a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1547a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 15487aa6b4adSDavidlohr Bueso * cleanup path of mmap_region. When 1549a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 15507aa6b4adSDavidlohr Bueso * mmap_region() nullifies vma->vm_file 1551a137e1ccSAndi Kleen * before calling this function to clean up. 1552a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1553a137e1ccSAndi Kleen * safe to do nothing in this case. 1554a137e1ccSAndi Kleen */ 155524669e58SAneesh Kumar K.V if (vma->vm_file) { 155683cde9e8SDavidlohr Bueso i_mmap_lock_write(vma->vm_file->f_mapping); 1557d833352aSMel Gorman __unmap_hugepage_range_final(tlb, vma, start, end, NULL); 155883cde9e8SDavidlohr Bueso i_mmap_unlock_write(vma->vm_file->f_mapping); 155924669e58SAneesh Kumar K.V } 156051c6f666SRobin Holt } else 1561038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 156297a89413SPeter Zijlstra } 156351c6f666SRobin Holt } 15641da177e4SLinus Torvalds 1565f5cc4eefSAl Viro /** 1566f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1567f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1568f5cc4eefSAl Viro * @vma: the starting vma 1569f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1570f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1571f5cc4eefSAl Viro * 1572f5cc4eefSAl Viro * Unmap all pages in the vma list. 1573f5cc4eefSAl Viro * 1574f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1575f5cc4eefSAl Viro * 1576f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1577f5cc4eefSAl Viro * 1578f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1579f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1580f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1581f5cc4eefSAl Viro * drops the lock and schedules. 1582f5cc4eefSAl Viro */ 1583f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1584f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 15854f74d2c8SLinus Torvalds unsigned long end_addr) 1586f5cc4eefSAl Viro { 1587f5cc4eefSAl Viro struct mm_struct *mm = vma->vm_mm; 1588f5cc4eefSAl Viro 1589f5cc4eefSAl Viro mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); 1590f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 15914f74d2c8SLinus Torvalds unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); 1592cddb8a5cSAndrea Arcangeli mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); 15931da177e4SLinus Torvalds } 15941da177e4SLinus Torvalds 15951da177e4SLinus Torvalds /** 15961da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 15971da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1598eb4546bbSRandy Dunlap * @start: starting address of pages to zap 15991da177e4SLinus Torvalds * @size: number of bytes to zap 1600f5cc4eefSAl Viro * 1601f5cc4eefSAl Viro * Caller must protect the VMA list 16021da177e4SLinus Torvalds */ 16037e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 1604ecf1385dSKirill A. Shutemov unsigned long size) 16051da177e4SLinus Torvalds { 16061da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 1607d16dfc55SPeter Zijlstra struct mmu_gather tlb; 16087e027b14SLinus Torvalds unsigned long end = start + size; 16091da177e4SLinus Torvalds 16101da177e4SLinus Torvalds lru_add_drain(); 16112b047252SLinus Torvalds tlb_gather_mmu(&tlb, mm, start, end); 1612365e9c87SHugh Dickins update_hiwater_rss(mm); 16137e027b14SLinus Torvalds mmu_notifier_invalidate_range_start(mm, start, end); 16144647706eSMel Gorman for ( ; vma && vma->vm_start < end; vma = vma->vm_next) { 1615ecf1385dSKirill A. Shutemov unmap_single_vma(&tlb, vma, start, end, NULL); 16164647706eSMel Gorman 16174647706eSMel Gorman /* 16184647706eSMel Gorman * zap_page_range does not specify whether mmap_sem should be 16194647706eSMel Gorman * held for read or write. That allows parallel zap_page_range 16204647706eSMel Gorman * operations to unmap a PTE and defer a flush meaning that 16214647706eSMel Gorman * this call observes pte_none and fails to flush the TLB. 16224647706eSMel Gorman * Rather than adding a complex API, ensure that no stale 16234647706eSMel Gorman * TLB entries exist when this call returns. 16244647706eSMel Gorman */ 16254647706eSMel Gorman flush_tlb_range(vma, start, end); 16264647706eSMel Gorman } 16274647706eSMel Gorman 16287e027b14SLinus Torvalds mmu_notifier_invalidate_range_end(mm, start, end); 16297e027b14SLinus Torvalds tlb_finish_mmu(&tlb, start, end); 16301da177e4SLinus Torvalds } 16311da177e4SLinus Torvalds 1632c627f9ccSJack Steiner /** 1633f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1634f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1635f5cc4eefSAl Viro * @address: starting address of pages to zap 1636f5cc4eefSAl Viro * @size: number of bytes to zap 16378a5f14a2SKirill A. Shutemov * @details: details of shared cache invalidation 1638f5cc4eefSAl Viro * 1639f5cc4eefSAl Viro * The range must fit into one VMA. 1640f5cc4eefSAl Viro */ 1641f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1642f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1643f5cc4eefSAl Viro { 1644f5cc4eefSAl Viro struct mm_struct *mm = vma->vm_mm; 1645f5cc4eefSAl Viro struct mmu_gather tlb; 1646f5cc4eefSAl Viro unsigned long end = address + size; 1647f5cc4eefSAl Viro 1648f5cc4eefSAl Viro lru_add_drain(); 16492b047252SLinus Torvalds tlb_gather_mmu(&tlb, mm, address, end); 1650f5cc4eefSAl Viro update_hiwater_rss(mm); 1651f5cc4eefSAl Viro mmu_notifier_invalidate_range_start(mm, address, end); 16524f74d2c8SLinus Torvalds unmap_single_vma(&tlb, vma, address, end, details); 1653f5cc4eefSAl Viro mmu_notifier_invalidate_range_end(mm, address, end); 1654f5cc4eefSAl Viro tlb_finish_mmu(&tlb, address, end); 16551da177e4SLinus Torvalds } 16561da177e4SLinus Torvalds 1657c627f9ccSJack Steiner /** 1658c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1659c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1660c627f9ccSJack Steiner * @address: starting address of pages to zap 1661c627f9ccSJack Steiner * @size: number of bytes to zap 1662c627f9ccSJack Steiner * 1663c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1664c627f9ccSJack Steiner * 1665c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1666c627f9ccSJack Steiner * 1667c627f9ccSJack Steiner * Returns 0 if successful. 1668c627f9ccSJack Steiner */ 1669c627f9ccSJack Steiner int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1670c627f9ccSJack Steiner unsigned long size) 1671c627f9ccSJack Steiner { 1672c627f9ccSJack Steiner if (address < vma->vm_start || address + size > vma->vm_end || 1673c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 1674c627f9ccSJack Steiner return -1; 1675f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1676c627f9ccSJack Steiner return 0; 1677c627f9ccSJack Steiner } 1678c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1679c627f9ccSJack Steiner 168025ca1d6cSNamhyung Kim pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 1681920c7a5dSHarvey Harrison spinlock_t **ptl) 1682c9cfcddfSLinus Torvalds { 1683c2febafcSKirill A. Shutemov pgd_t *pgd; 1684c2febafcSKirill A. Shutemov p4d_t *p4d; 1685c2febafcSKirill A. Shutemov pud_t *pud; 1686c2febafcSKirill A. Shutemov pmd_t *pmd; 1687c2febafcSKirill A. Shutemov 1688c2febafcSKirill A. Shutemov pgd = pgd_offset(mm, addr); 1689c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 1690c2febafcSKirill A. Shutemov if (!p4d) 1691c2febafcSKirill A. Shutemov return NULL; 1692c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 1693c2febafcSKirill A. Shutemov if (!pud) 1694c2febafcSKirill A. Shutemov return NULL; 1695c2febafcSKirill A. Shutemov pmd = pmd_alloc(mm, pud, addr); 1696c2febafcSKirill A. Shutemov if (!pmd) 1697c2febafcSKirill A. Shutemov return NULL; 1698c2febafcSKirill A. Shutemov 1699f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 1700c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 1701c9cfcddfSLinus Torvalds } 1702c9cfcddfSLinus Torvalds 17031da177e4SLinus Torvalds /* 1704238f58d8SLinus Torvalds * This is the old fallback for page remapping. 1705238f58d8SLinus Torvalds * 1706238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 1707238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 1708238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 1709238f58d8SLinus Torvalds */ 1710423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 1711423bad60SNick Piggin struct page *page, pgprot_t prot) 1712238f58d8SLinus Torvalds { 1713423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 1714238f58d8SLinus Torvalds int retval; 1715238f58d8SLinus Torvalds pte_t *pte; 1716238f58d8SLinus Torvalds spinlock_t *ptl; 1717238f58d8SLinus Torvalds 1718238f58d8SLinus Torvalds retval = -EINVAL; 1719a145dd41SLinus Torvalds if (PageAnon(page)) 17205b4e655eSKAMEZAWA Hiroyuki goto out; 1721238f58d8SLinus Torvalds retval = -ENOMEM; 1722238f58d8SLinus Torvalds flush_dcache_page(page); 1723c9cfcddfSLinus Torvalds pte = get_locked_pte(mm, addr, &ptl); 1724238f58d8SLinus Torvalds if (!pte) 17255b4e655eSKAMEZAWA Hiroyuki goto out; 1726238f58d8SLinus Torvalds retval = -EBUSY; 1727238f58d8SLinus Torvalds if (!pte_none(*pte)) 1728238f58d8SLinus Torvalds goto out_unlock; 1729238f58d8SLinus Torvalds 1730238f58d8SLinus Torvalds /* Ok, finally just insert the thing.. */ 1731238f58d8SLinus Torvalds get_page(page); 1732eca56ff9SJerome Marchand inc_mm_counter_fast(mm, mm_counter_file(page)); 1733dd78feddSKirill A. Shutemov page_add_file_rmap(page, false); 1734238f58d8SLinus Torvalds set_pte_at(mm, addr, pte, mk_pte(page, prot)); 1735238f58d8SLinus Torvalds 1736238f58d8SLinus Torvalds retval = 0; 17378a9f3ccdSBalbir Singh pte_unmap_unlock(pte, ptl); 17388a9f3ccdSBalbir Singh return retval; 1739238f58d8SLinus Torvalds out_unlock: 1740238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 1741238f58d8SLinus Torvalds out: 1742238f58d8SLinus Torvalds return retval; 1743238f58d8SLinus Torvalds } 1744238f58d8SLinus Torvalds 1745bfa5bf6dSRolf Eike Beer /** 1746bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 1747bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 1748bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 1749bfa5bf6dSRolf Eike Beer * @page: source kernel page 1750bfa5bf6dSRolf Eike Beer * 1751a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 1752a145dd41SLinus Torvalds * into a user vma. 1753a145dd41SLinus Torvalds * 1754a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 1755a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 1756a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 17578dfcc9baSNick Piggin * (see split_page()). 1758a145dd41SLinus Torvalds * 1759a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 1760a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 1761a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 1762a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 1763a145dd41SLinus Torvalds * ask for a shared writable mapping! 1764a145dd41SLinus Torvalds * 1765a145dd41SLinus Torvalds * The page does not need to be reserved. 17664b6e1e37SKonstantin Khlebnikov * 17674b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 17684b6e1e37SKonstantin Khlebnikov * under mm->mmap_sem write-lock, so it can change vma->vm_flags. 17694b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 17704b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 1771a145dd41SLinus Torvalds */ 1772423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 1773423bad60SNick Piggin struct page *page) 1774a145dd41SLinus Torvalds { 1775a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 1776a145dd41SLinus Torvalds return -EFAULT; 1777a145dd41SLinus Torvalds if (!page_count(page)) 1778a145dd41SLinus Torvalds return -EINVAL; 17794b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 17804b6e1e37SKonstantin Khlebnikov BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem)); 17814b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 17824b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 17834b6e1e37SKonstantin Khlebnikov } 1784423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 1785a145dd41SLinus Torvalds } 1786e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 1787a145dd41SLinus Torvalds 1788423bad60SNick Piggin static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, 1789b2770da6SRoss Zwisler pfn_t pfn, pgprot_t prot, bool mkwrite) 1790423bad60SNick Piggin { 1791423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 1792423bad60SNick Piggin int retval; 1793423bad60SNick Piggin pte_t *pte, entry; 1794423bad60SNick Piggin spinlock_t *ptl; 1795423bad60SNick Piggin 1796423bad60SNick Piggin retval = -ENOMEM; 1797423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 1798423bad60SNick Piggin if (!pte) 1799423bad60SNick Piggin goto out; 1800423bad60SNick Piggin retval = -EBUSY; 1801b2770da6SRoss Zwisler if (!pte_none(*pte)) { 1802b2770da6SRoss Zwisler if (mkwrite) { 1803b2770da6SRoss Zwisler /* 1804b2770da6SRoss Zwisler * For read faults on private mappings the PFN passed 1805b2770da6SRoss Zwisler * in may not match the PFN we have mapped if the 1806b2770da6SRoss Zwisler * mapped PFN is a writeable COW page. In the mkwrite 1807b2770da6SRoss Zwisler * case we are creating a writable PTE for a shared 1808b2770da6SRoss Zwisler * mapping and we expect the PFNs to match. 1809b2770da6SRoss Zwisler */ 1810b2770da6SRoss Zwisler if (WARN_ON_ONCE(pte_pfn(*pte) != pfn_t_to_pfn(pfn))) 1811423bad60SNick Piggin goto out_unlock; 1812b2770da6SRoss Zwisler entry = *pte; 1813b2770da6SRoss Zwisler goto out_mkwrite; 1814b2770da6SRoss Zwisler } else 1815b2770da6SRoss Zwisler goto out_unlock; 1816b2770da6SRoss Zwisler } 1817423bad60SNick Piggin 1818423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 181901c8f1c4SDan Williams if (pfn_t_devmap(pfn)) 182001c8f1c4SDan Williams entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); 182101c8f1c4SDan Williams else 182201c8f1c4SDan Williams entry = pte_mkspecial(pfn_t_pte(pfn, prot)); 1823b2770da6SRoss Zwisler 1824b2770da6SRoss Zwisler out_mkwrite: 1825b2770da6SRoss Zwisler if (mkwrite) { 1826b2770da6SRoss Zwisler entry = pte_mkyoung(entry); 1827b2770da6SRoss Zwisler entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1828b2770da6SRoss Zwisler } 1829b2770da6SRoss Zwisler 1830423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 18314b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 1832423bad60SNick Piggin 1833423bad60SNick Piggin retval = 0; 1834423bad60SNick Piggin out_unlock: 1835423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 1836423bad60SNick Piggin out: 1837423bad60SNick Piggin return retval; 1838423bad60SNick Piggin } 1839423bad60SNick Piggin 1840e0dc0d8fSNick Piggin /** 1841e0dc0d8fSNick Piggin * vm_insert_pfn - insert single pfn into user vma 1842e0dc0d8fSNick Piggin * @vma: user vma to map to 1843e0dc0d8fSNick Piggin * @addr: target user address of this page 1844e0dc0d8fSNick Piggin * @pfn: source kernel pfn 1845e0dc0d8fSNick Piggin * 1846c462f179SRobert P. J. Day * Similar to vm_insert_page, this allows drivers to insert individual pages 1847e0dc0d8fSNick Piggin * they've allocated into a user vma. Same comments apply. 1848e0dc0d8fSNick Piggin * 1849e0dc0d8fSNick Piggin * This function should only be called from a vm_ops->fault handler, and 1850e0dc0d8fSNick Piggin * in that case the handler should return NULL. 18510d71d10aSNick Piggin * 18520d71d10aSNick Piggin * vma cannot be a COW mapping. 18530d71d10aSNick Piggin * 18540d71d10aSNick Piggin * As this is called only for pages that do not currently exist, we 18550d71d10aSNick Piggin * do not need to flush old virtual caches or the TLB. 1856e0dc0d8fSNick Piggin */ 1857e0dc0d8fSNick Piggin int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 1858e0dc0d8fSNick Piggin unsigned long pfn) 1859e0dc0d8fSNick Piggin { 18601745cbc5SAndy Lutomirski return vm_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); 18611745cbc5SAndy Lutomirski } 18621745cbc5SAndy Lutomirski EXPORT_SYMBOL(vm_insert_pfn); 18631745cbc5SAndy Lutomirski 18641745cbc5SAndy Lutomirski /** 18651745cbc5SAndy Lutomirski * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot 18661745cbc5SAndy Lutomirski * @vma: user vma to map to 18671745cbc5SAndy Lutomirski * @addr: target user address of this page 18681745cbc5SAndy Lutomirski * @pfn: source kernel pfn 18691745cbc5SAndy Lutomirski * @pgprot: pgprot flags for the inserted page 18701745cbc5SAndy Lutomirski * 18711745cbc5SAndy Lutomirski * This is exactly like vm_insert_pfn, except that it allows drivers to 18721745cbc5SAndy Lutomirski * to override pgprot on a per-page basis. 18731745cbc5SAndy Lutomirski * 18741745cbc5SAndy Lutomirski * This only makes sense for IO mappings, and it makes no sense for 18751745cbc5SAndy Lutomirski * cow mappings. In general, using multiple vmas is preferable; 18761745cbc5SAndy Lutomirski * vm_insert_pfn_prot should only be used if using multiple VMAs is 18771745cbc5SAndy Lutomirski * impractical. 18781745cbc5SAndy Lutomirski */ 18791745cbc5SAndy Lutomirski int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, 18801745cbc5SAndy Lutomirski unsigned long pfn, pgprot_t pgprot) 18811745cbc5SAndy Lutomirski { 18822ab64037Svenkatesh.pallipadi@intel.com int ret; 18837e675137SNick Piggin /* 18847e675137SNick Piggin * Technically, architectures with pte_special can avoid all these 18857e675137SNick Piggin * restrictions (same for remap_pfn_range). However we would like 18867e675137SNick Piggin * consistency in testing and feature parity among all, so we should 18877e675137SNick Piggin * try to keep these invariants in place for everybody. 18887e675137SNick Piggin */ 1889b379d790SJared Hulbert BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 1890b379d790SJared Hulbert BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 1891b379d790SJared Hulbert (VM_PFNMAP|VM_MIXEDMAP)); 1892b379d790SJared Hulbert BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 1893b379d790SJared Hulbert BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 1894e0dc0d8fSNick Piggin 1895423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 1896423bad60SNick Piggin return -EFAULT; 1897308a047cSBorislav Petkov 1898308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); 18992ab64037Svenkatesh.pallipadi@intel.com 1900b2770da6SRoss Zwisler ret = insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, 1901b2770da6SRoss Zwisler false); 19022ab64037Svenkatesh.pallipadi@intel.com 19032ab64037Svenkatesh.pallipadi@intel.com return ret; 1904e0dc0d8fSNick Piggin } 19051745cbc5SAndy Lutomirski EXPORT_SYMBOL(vm_insert_pfn_prot); 1906e0dc0d8fSNick Piggin 1907b2770da6SRoss Zwisler static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 1908b2770da6SRoss Zwisler pfn_t pfn, bool mkwrite) 1909423bad60SNick Piggin { 191087744ab3SDan Williams pgprot_t pgprot = vma->vm_page_prot; 191187744ab3SDan Williams 1912423bad60SNick Piggin BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); 1913423bad60SNick Piggin 1914423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 1915423bad60SNick Piggin return -EFAULT; 1916308a047cSBorislav Petkov 1917308a047cSBorislav Petkov track_pfn_insert(vma, &pgprot, pfn); 1918423bad60SNick Piggin 1919423bad60SNick Piggin /* 1920423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 1921423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 1922423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 192362eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 192462eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 1925423bad60SNick Piggin */ 192603fc2da6SDan Williams if (!HAVE_PTE_SPECIAL && !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { 1927423bad60SNick Piggin struct page *page; 1928423bad60SNick Piggin 192903fc2da6SDan Williams /* 193003fc2da6SDan Williams * At this point we are committed to insert_page() 193103fc2da6SDan Williams * regardless of whether the caller specified flags that 193203fc2da6SDan Williams * result in pfn_t_has_page() == false. 193303fc2da6SDan Williams */ 193403fc2da6SDan Williams page = pfn_to_page(pfn_t_to_pfn(pfn)); 193587744ab3SDan Williams return insert_page(vma, addr, page, pgprot); 1936423bad60SNick Piggin } 1937b2770da6SRoss Zwisler return insert_pfn(vma, addr, pfn, pgprot, mkwrite); 1938b2770da6SRoss Zwisler } 1939b2770da6SRoss Zwisler 1940b2770da6SRoss Zwisler int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 1941b2770da6SRoss Zwisler pfn_t pfn) 1942b2770da6SRoss Zwisler { 1943b2770da6SRoss Zwisler return __vm_insert_mixed(vma, addr, pfn, false); 1944b2770da6SRoss Zwisler 1945423bad60SNick Piggin } 1946423bad60SNick Piggin EXPORT_SYMBOL(vm_insert_mixed); 1947423bad60SNick Piggin 1948b2770da6SRoss Zwisler int vm_insert_mixed_mkwrite(struct vm_area_struct *vma, unsigned long addr, 1949b2770da6SRoss Zwisler pfn_t pfn) 1950b2770da6SRoss Zwisler { 1951b2770da6SRoss Zwisler return __vm_insert_mixed(vma, addr, pfn, true); 1952b2770da6SRoss Zwisler } 1953b2770da6SRoss Zwisler EXPORT_SYMBOL(vm_insert_mixed_mkwrite); 1954b2770da6SRoss Zwisler 1955a145dd41SLinus Torvalds /* 19561da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 19571da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 19581da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 19591da177e4SLinus Torvalds */ 19601da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 19611da177e4SLinus Torvalds unsigned long addr, unsigned long end, 19621da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 19631da177e4SLinus Torvalds { 19641da177e4SLinus Torvalds pte_t *pte; 1965c74df32cSHugh Dickins spinlock_t *ptl; 19661da177e4SLinus Torvalds 1967c74df32cSHugh Dickins pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 19681da177e4SLinus Torvalds if (!pte) 19691da177e4SLinus Torvalds return -ENOMEM; 19706606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 19711da177e4SLinus Torvalds do { 19721da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 19737e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 19741da177e4SLinus Torvalds pfn++; 19751da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 19766606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 1977c74df32cSHugh Dickins pte_unmap_unlock(pte - 1, ptl); 19781da177e4SLinus Torvalds return 0; 19791da177e4SLinus Torvalds } 19801da177e4SLinus Torvalds 19811da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 19821da177e4SLinus Torvalds unsigned long addr, unsigned long end, 19831da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 19841da177e4SLinus Torvalds { 19851da177e4SLinus Torvalds pmd_t *pmd; 19861da177e4SLinus Torvalds unsigned long next; 19871da177e4SLinus Torvalds 19881da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 19891da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 19901da177e4SLinus Torvalds if (!pmd) 19911da177e4SLinus Torvalds return -ENOMEM; 1992f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 19931da177e4SLinus Torvalds do { 19941da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 19951da177e4SLinus Torvalds if (remap_pte_range(mm, pmd, addr, next, 19961da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 19971da177e4SLinus Torvalds return -ENOMEM; 19981da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 19991da177e4SLinus Torvalds return 0; 20001da177e4SLinus Torvalds } 20011da177e4SLinus Torvalds 2002c2febafcSKirill A. Shutemov static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, 20031da177e4SLinus Torvalds unsigned long addr, unsigned long end, 20041da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 20051da177e4SLinus Torvalds { 20061da177e4SLinus Torvalds pud_t *pud; 20071da177e4SLinus Torvalds unsigned long next; 20081da177e4SLinus Torvalds 20091da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 2010c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 20111da177e4SLinus Torvalds if (!pud) 20121da177e4SLinus Torvalds return -ENOMEM; 20131da177e4SLinus Torvalds do { 20141da177e4SLinus Torvalds next = pud_addr_end(addr, end); 20151da177e4SLinus Torvalds if (remap_pmd_range(mm, pud, addr, next, 20161da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 20171da177e4SLinus Torvalds return -ENOMEM; 20181da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 20191da177e4SLinus Torvalds return 0; 20201da177e4SLinus Torvalds } 20211da177e4SLinus Torvalds 2022c2febafcSKirill A. Shutemov static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2023c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2024c2febafcSKirill A. Shutemov unsigned long pfn, pgprot_t prot) 2025c2febafcSKirill A. Shutemov { 2026c2febafcSKirill A. Shutemov p4d_t *p4d; 2027c2febafcSKirill A. Shutemov unsigned long next; 2028c2febafcSKirill A. Shutemov 2029c2febafcSKirill A. Shutemov pfn -= addr >> PAGE_SHIFT; 2030c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2031c2febafcSKirill A. Shutemov if (!p4d) 2032c2febafcSKirill A. Shutemov return -ENOMEM; 2033c2febafcSKirill A. Shutemov do { 2034c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 2035c2febafcSKirill A. Shutemov if (remap_pud_range(mm, p4d, addr, next, 2036c2febafcSKirill A. Shutemov pfn + (addr >> PAGE_SHIFT), prot)) 2037c2febafcSKirill A. Shutemov return -ENOMEM; 2038c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2039c2febafcSKirill A. Shutemov return 0; 2040c2febafcSKirill A. Shutemov } 2041c2febafcSKirill A. Shutemov 2042bfa5bf6dSRolf Eike Beer /** 2043bfa5bf6dSRolf Eike Beer * remap_pfn_range - remap kernel memory to userspace 2044bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2045bfa5bf6dSRolf Eike Beer * @addr: target user address to start at 2046bfa5bf6dSRolf Eike Beer * @pfn: physical address of kernel memory 2047bfa5bf6dSRolf Eike Beer * @size: size of map area 2048bfa5bf6dSRolf Eike Beer * @prot: page protection flags for this mapping 2049bfa5bf6dSRolf Eike Beer * 2050bfa5bf6dSRolf Eike Beer * Note: this is only safe if the mm semaphore is held when called. 2051bfa5bf6dSRolf Eike Beer */ 20521da177e4SLinus Torvalds int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 20531da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 20541da177e4SLinus Torvalds { 20551da177e4SLinus Torvalds pgd_t *pgd; 20561da177e4SLinus Torvalds unsigned long next; 20572d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 20581da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 2059d5957d2fSYongji Xie unsigned long remap_pfn = pfn; 20601da177e4SLinus Torvalds int err; 20611da177e4SLinus Torvalds 20621da177e4SLinus Torvalds /* 20631da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 20641da177e4SLinus Torvalds * rest of the world about it: 20651da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 20661da177e4SLinus Torvalds * (accesses can have side effects). 20676aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 20686aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 20696aab341eSLinus Torvalds * with them. 2070314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2071314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2072314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2073314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2074fb155c16SLinus Torvalds * 2075fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2076fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2077fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2078b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 20791da177e4SLinus Torvalds */ 2080b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2081b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2082b3b9c293SKonstantin Khlebnikov return -EINVAL; 20836aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2084b3b9c293SKonstantin Khlebnikov } 2085b3b9c293SKonstantin Khlebnikov 2086d5957d2fSYongji Xie err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size)); 2087b3b9c293SKonstantin Khlebnikov if (err) 20883c8bb73aSvenkatesh.pallipadi@intel.com return -EINVAL; 2089fb155c16SLinus Torvalds 2090314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 20911da177e4SLinus Torvalds 20921da177e4SLinus Torvalds BUG_ON(addr >= end); 20931da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 20941da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 20951da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 20961da177e4SLinus Torvalds do { 20971da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2098c2febafcSKirill A. Shutemov err = remap_p4d_range(mm, pgd, addr, next, 20991da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 21001da177e4SLinus Torvalds if (err) 21011da177e4SLinus Torvalds break; 21021da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 21032ab64037Svenkatesh.pallipadi@intel.com 21042ab64037Svenkatesh.pallipadi@intel.com if (err) 2105d5957d2fSYongji Xie untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size)); 21062ab64037Svenkatesh.pallipadi@intel.com 21071da177e4SLinus Torvalds return err; 21081da177e4SLinus Torvalds } 21091da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 21101da177e4SLinus Torvalds 2111b4cbb197SLinus Torvalds /** 2112b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2113b4cbb197SLinus Torvalds * @vma: user vma to map to 2114b4cbb197SLinus Torvalds * @start: start of area 2115b4cbb197SLinus Torvalds * @len: size of area 2116b4cbb197SLinus Torvalds * 2117b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2118b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2119b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2120b4cbb197SLinus Torvalds * 2121b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2122b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2123b4cbb197SLinus Torvalds */ 2124b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2125b4cbb197SLinus Torvalds { 2126b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2127b4cbb197SLinus Torvalds 2128b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2129b4cbb197SLinus Torvalds if (start + len < start) 2130b4cbb197SLinus Torvalds return -EINVAL; 2131b4cbb197SLinus Torvalds /* 2132b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2133b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2134b4cbb197SLinus Torvalds * just have smaller alignment. 2135b4cbb197SLinus Torvalds */ 2136b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2137b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2138b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2139b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2140b4cbb197SLinus Torvalds return -EINVAL; 2141b4cbb197SLinus Torvalds 2142b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2143b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2144b4cbb197SLinus Torvalds return -EINVAL; 2145b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2146b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2147b4cbb197SLinus Torvalds 2148b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2149b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2150b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2151b4cbb197SLinus Torvalds return -EINVAL; 2152b4cbb197SLinus Torvalds 2153b4cbb197SLinus Torvalds /* Ok, let it rip */ 2154b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2155b4cbb197SLinus Torvalds } 2156b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2157b4cbb197SLinus Torvalds 2158aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2159aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2160aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2161aee16b3cSJeremy Fitzhardinge { 2162aee16b3cSJeremy Fitzhardinge pte_t *pte; 2163aee16b3cSJeremy Fitzhardinge int err; 21642f569afdSMartin Schwidefsky pgtable_t token; 216594909914SBorislav Petkov spinlock_t *uninitialized_var(ptl); 2166aee16b3cSJeremy Fitzhardinge 2167aee16b3cSJeremy Fitzhardinge pte = (mm == &init_mm) ? 2168aee16b3cSJeremy Fitzhardinge pte_alloc_kernel(pmd, addr) : 2169aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2170aee16b3cSJeremy Fitzhardinge if (!pte) 2171aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2172aee16b3cSJeremy Fitzhardinge 2173aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2174aee16b3cSJeremy Fitzhardinge 217538e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 217638e0edb1SJeremy Fitzhardinge 21772f569afdSMartin Schwidefsky token = pmd_pgtable(*pmd); 2178aee16b3cSJeremy Fitzhardinge 2179aee16b3cSJeremy Fitzhardinge do { 2180c36987e2SDaisuke Nishimura err = fn(pte++, token, addr, data); 2181aee16b3cSJeremy Fitzhardinge if (err) 2182aee16b3cSJeremy Fitzhardinge break; 2183c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2184aee16b3cSJeremy Fitzhardinge 218538e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 218638e0edb1SJeremy Fitzhardinge 2187aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 2188aee16b3cSJeremy Fitzhardinge pte_unmap_unlock(pte-1, ptl); 2189aee16b3cSJeremy Fitzhardinge return err; 2190aee16b3cSJeremy Fitzhardinge } 2191aee16b3cSJeremy Fitzhardinge 2192aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2193aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2194aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2195aee16b3cSJeremy Fitzhardinge { 2196aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2197aee16b3cSJeremy Fitzhardinge unsigned long next; 2198aee16b3cSJeremy Fitzhardinge int err; 2199aee16b3cSJeremy Fitzhardinge 2200ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2201ceb86879SAndi Kleen 2202aee16b3cSJeremy Fitzhardinge pmd = pmd_alloc(mm, pud, addr); 2203aee16b3cSJeremy Fitzhardinge if (!pmd) 2204aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2205aee16b3cSJeremy Fitzhardinge do { 2206aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 2207aee16b3cSJeremy Fitzhardinge err = apply_to_pte_range(mm, pmd, addr, next, fn, data); 2208aee16b3cSJeremy Fitzhardinge if (err) 2209aee16b3cSJeremy Fitzhardinge break; 2210aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 2211aee16b3cSJeremy Fitzhardinge return err; 2212aee16b3cSJeremy Fitzhardinge } 2213aee16b3cSJeremy Fitzhardinge 2214c2febafcSKirill A. Shutemov static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, 2215aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2216aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2217aee16b3cSJeremy Fitzhardinge { 2218aee16b3cSJeremy Fitzhardinge pud_t *pud; 2219aee16b3cSJeremy Fitzhardinge unsigned long next; 2220aee16b3cSJeremy Fitzhardinge int err; 2221aee16b3cSJeremy Fitzhardinge 2222c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, addr); 2223aee16b3cSJeremy Fitzhardinge if (!pud) 2224aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2225aee16b3cSJeremy Fitzhardinge do { 2226aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 2227aee16b3cSJeremy Fitzhardinge err = apply_to_pmd_range(mm, pud, addr, next, fn, data); 2228aee16b3cSJeremy Fitzhardinge if (err) 2229aee16b3cSJeremy Fitzhardinge break; 2230aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 2231aee16b3cSJeremy Fitzhardinge return err; 2232aee16b3cSJeremy Fitzhardinge } 2233aee16b3cSJeremy Fitzhardinge 2234c2febafcSKirill A. Shutemov static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, 2235c2febafcSKirill A. Shutemov unsigned long addr, unsigned long end, 2236c2febafcSKirill A. Shutemov pte_fn_t fn, void *data) 2237c2febafcSKirill A. Shutemov { 2238c2febafcSKirill A. Shutemov p4d_t *p4d; 2239c2febafcSKirill A. Shutemov unsigned long next; 2240c2febafcSKirill A. Shutemov int err; 2241c2febafcSKirill A. Shutemov 2242c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, addr); 2243c2febafcSKirill A. Shutemov if (!p4d) 2244c2febafcSKirill A. Shutemov return -ENOMEM; 2245c2febafcSKirill A. Shutemov do { 2246c2febafcSKirill A. Shutemov next = p4d_addr_end(addr, end); 2247c2febafcSKirill A. Shutemov err = apply_to_pud_range(mm, p4d, addr, next, fn, data); 2248c2febafcSKirill A. Shutemov if (err) 2249c2febafcSKirill A. Shutemov break; 2250c2febafcSKirill A. Shutemov } while (p4d++, addr = next, addr != end); 2251c2febafcSKirill A. Shutemov return err; 2252c2febafcSKirill A. Shutemov } 2253c2febafcSKirill A. Shutemov 2254aee16b3cSJeremy Fitzhardinge /* 2255aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2256aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2257aee16b3cSJeremy Fitzhardinge */ 2258aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2259aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2260aee16b3cSJeremy Fitzhardinge { 2261aee16b3cSJeremy Fitzhardinge pgd_t *pgd; 2262aee16b3cSJeremy Fitzhardinge unsigned long next; 226357250a5bSJeremy Fitzhardinge unsigned long end = addr + size; 2264aee16b3cSJeremy Fitzhardinge int err; 2265aee16b3cSJeremy Fitzhardinge 22669cb65bc3SMika Penttilä if (WARN_ON(addr >= end)) 22679cb65bc3SMika Penttilä return -EINVAL; 22689cb65bc3SMika Penttilä 2269aee16b3cSJeremy Fitzhardinge pgd = pgd_offset(mm, addr); 2270aee16b3cSJeremy Fitzhardinge do { 2271aee16b3cSJeremy Fitzhardinge next = pgd_addr_end(addr, end); 2272c2febafcSKirill A. Shutemov err = apply_to_p4d_range(mm, pgd, addr, next, fn, data); 2273aee16b3cSJeremy Fitzhardinge if (err) 2274aee16b3cSJeremy Fitzhardinge break; 2275aee16b3cSJeremy Fitzhardinge } while (pgd++, addr = next, addr != end); 227657250a5bSJeremy Fitzhardinge 2277aee16b3cSJeremy Fitzhardinge return err; 2278aee16b3cSJeremy Fitzhardinge } 2279aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2280aee16b3cSJeremy Fitzhardinge 22811da177e4SLinus Torvalds /* 22829b4bdd2fSKirill A. Shutemov * handle_pte_fault chooses page fault handler according to an entry which was 22839b4bdd2fSKirill A. Shutemov * read non-atomically. Before making any commitment, on those architectures 22849b4bdd2fSKirill A. Shutemov * or configurations (e.g. i386 with PAE) which might give a mix of unmatched 22859b4bdd2fSKirill A. Shutemov * parts, do_swap_page must check under lock before unmapping the pte and 22869b4bdd2fSKirill A. Shutemov * proceeding (but do_wp_page is only called after already making such a check; 2287a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 22888f4e2101SHugh Dickins */ 22894c21e2f2SHugh Dickins static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 22908f4e2101SHugh Dickins pte_t *page_table, pte_t orig_pte) 22918f4e2101SHugh Dickins { 22928f4e2101SHugh Dickins int same = 1; 22938f4e2101SHugh Dickins #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) 22948f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 22954c21e2f2SHugh Dickins spinlock_t *ptl = pte_lockptr(mm, pmd); 22964c21e2f2SHugh Dickins spin_lock(ptl); 22978f4e2101SHugh Dickins same = pte_same(*page_table, orig_pte); 22984c21e2f2SHugh Dickins spin_unlock(ptl); 22998f4e2101SHugh Dickins } 23008f4e2101SHugh Dickins #endif 23018f4e2101SHugh Dickins pte_unmap(page_table); 23028f4e2101SHugh Dickins return same; 23038f4e2101SHugh Dickins } 23048f4e2101SHugh Dickins 23059de455b2SAtsushi Nemoto static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) 23066aab341eSLinus Torvalds { 23070abdd7a8SDan Williams debug_dma_assert_idle(src); 23080abdd7a8SDan Williams 23096aab341eSLinus Torvalds /* 23106aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 23116aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 23126aab341eSLinus Torvalds * just copying from the original user address. If that 23136aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 23146aab341eSLinus Torvalds */ 23156aab341eSLinus Torvalds if (unlikely(!src)) { 23169b04c5feSCong Wang void *kaddr = kmap_atomic(dst); 23175d2a2dbbSLinus Torvalds void __user *uaddr = (void __user *)(va & PAGE_MASK); 23185d2a2dbbSLinus Torvalds 23195d2a2dbbSLinus Torvalds /* 23205d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 23215d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 23225d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 23235d2a2dbbSLinus Torvalds * zeroes. 23245d2a2dbbSLinus Torvalds */ 23255d2a2dbbSLinus Torvalds if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) 23263ecb01dfSJan Beulich clear_page(kaddr); 23279b04c5feSCong Wang kunmap_atomic(kaddr); 2328c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 23290ed361deSNick Piggin } else 23309de455b2SAtsushi Nemoto copy_user_highpage(dst, src, va, vma); 23316aab341eSLinus Torvalds } 23326aab341eSLinus Torvalds 2333c20cd45eSMichal Hocko static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) 2334c20cd45eSMichal Hocko { 2335c20cd45eSMichal Hocko struct file *vm_file = vma->vm_file; 2336c20cd45eSMichal Hocko 2337c20cd45eSMichal Hocko if (vm_file) 2338c20cd45eSMichal Hocko return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; 2339c20cd45eSMichal Hocko 2340c20cd45eSMichal Hocko /* 2341c20cd45eSMichal Hocko * Special mappings (e.g. VDSO) do not have any file so fake 2342c20cd45eSMichal Hocko * a default GFP_KERNEL for them. 2343c20cd45eSMichal Hocko */ 2344c20cd45eSMichal Hocko return GFP_KERNEL; 2345c20cd45eSMichal Hocko } 2346c20cd45eSMichal Hocko 23471da177e4SLinus Torvalds /* 2348fb09a464SKirill A. Shutemov * Notify the address space that the page is about to become writable so that 2349fb09a464SKirill A. Shutemov * it can prohibit this or wait for the page to get into an appropriate state. 2350fb09a464SKirill A. Shutemov * 2351fb09a464SKirill A. Shutemov * We do this without the lock held, so that it can sleep if it needs to. 2352fb09a464SKirill A. Shutemov */ 235338b8cb7fSJan Kara static int do_page_mkwrite(struct vm_fault *vmf) 2354fb09a464SKirill A. Shutemov { 2355fb09a464SKirill A. Shutemov int ret; 235638b8cb7fSJan Kara struct page *page = vmf->page; 235738b8cb7fSJan Kara unsigned int old_flags = vmf->flags; 2358fb09a464SKirill A. Shutemov 235938b8cb7fSJan Kara vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2360fb09a464SKirill A. Shutemov 236111bac800SDave Jiang ret = vmf->vma->vm_ops->page_mkwrite(vmf); 236238b8cb7fSJan Kara /* Restore original flags so that caller is not surprised */ 236338b8cb7fSJan Kara vmf->flags = old_flags; 2364fb09a464SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2365fb09a464SKirill A. Shutemov return ret; 2366fb09a464SKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) { 2367fb09a464SKirill A. Shutemov lock_page(page); 2368fb09a464SKirill A. Shutemov if (!page->mapping) { 2369fb09a464SKirill A. Shutemov unlock_page(page); 2370fb09a464SKirill A. Shutemov return 0; /* retry */ 2371fb09a464SKirill A. Shutemov } 2372fb09a464SKirill A. Shutemov ret |= VM_FAULT_LOCKED; 2373fb09a464SKirill A. Shutemov } else 2374fb09a464SKirill A. Shutemov VM_BUG_ON_PAGE(!PageLocked(page), page); 2375fb09a464SKirill A. Shutemov return ret; 2376fb09a464SKirill A. Shutemov } 2377fb09a464SKirill A. Shutemov 2378fb09a464SKirill A. Shutemov /* 237997ba0c2bSJan Kara * Handle dirtying of a page in shared file mapping on a write fault. 23804e047f89SShachar Raindel * 238197ba0c2bSJan Kara * The function expects the page to be locked and unlocks it. 23824e047f89SShachar Raindel */ 238397ba0c2bSJan Kara static void fault_dirty_shared_page(struct vm_area_struct *vma, 238497ba0c2bSJan Kara struct page *page) 23854e047f89SShachar Raindel { 23864e047f89SShachar Raindel struct address_space *mapping; 238797ba0c2bSJan Kara bool dirtied; 238897ba0c2bSJan Kara bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite; 23894e047f89SShachar Raindel 23904e047f89SShachar Raindel dirtied = set_page_dirty(page); 23914e047f89SShachar Raindel VM_BUG_ON_PAGE(PageAnon(page), page); 239297ba0c2bSJan Kara /* 239397ba0c2bSJan Kara * Take a local copy of the address_space - page.mapping may be zeroed 239497ba0c2bSJan Kara * by truncate after unlock_page(). The address_space itself remains 239597ba0c2bSJan Kara * pinned by vma->vm_file's reference. We rely on unlock_page()'s 239697ba0c2bSJan Kara * release semantics to prevent the compiler from undoing this copying. 239797ba0c2bSJan Kara */ 239897ba0c2bSJan Kara mapping = page_rmapping(page); 23994e047f89SShachar Raindel unlock_page(page); 24004e047f89SShachar Raindel 24014e047f89SShachar Raindel if ((dirtied || page_mkwrite) && mapping) { 24024e047f89SShachar Raindel /* 24034e047f89SShachar Raindel * Some device drivers do not set page.mapping 24044e047f89SShachar Raindel * but still dirty their pages 24054e047f89SShachar Raindel */ 24064e047f89SShachar Raindel balance_dirty_pages_ratelimited(mapping); 24074e047f89SShachar Raindel } 24084e047f89SShachar Raindel 24094e047f89SShachar Raindel if (!page_mkwrite) 24104e047f89SShachar Raindel file_update_time(vma->vm_file); 24114e047f89SShachar Raindel } 24124e047f89SShachar Raindel 241397ba0c2bSJan Kara /* 24144e047f89SShachar Raindel * Handle write page faults for pages that can be reused in the current vma 24154e047f89SShachar Raindel * 24164e047f89SShachar Raindel * This can happen either due to the mapping being with the VM_SHARED flag, 24174e047f89SShachar Raindel * or due to us being the last reference standing to the page. In either 24184e047f89SShachar Raindel * case, all we need to do here is to mark the page as writable and update 24194e047f89SShachar Raindel * any related book-keeping. 24204e047f89SShachar Raindel */ 2421997dd98dSJan Kara static inline void wp_page_reuse(struct vm_fault *vmf) 242282b0f8c3SJan Kara __releases(vmf->ptl) 24234e047f89SShachar Raindel { 242482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2425a41b70d6SJan Kara struct page *page = vmf->page; 24264e047f89SShachar Raindel pte_t entry; 24274e047f89SShachar Raindel /* 24284e047f89SShachar Raindel * Clear the pages cpupid information as the existing 24294e047f89SShachar Raindel * information potentially belongs to a now completely 24304e047f89SShachar Raindel * unrelated process. 24314e047f89SShachar Raindel */ 24324e047f89SShachar Raindel if (page) 24334e047f89SShachar Raindel page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); 24344e047f89SShachar Raindel 24352994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 24362994302bSJan Kara entry = pte_mkyoung(vmf->orig_pte); 24374e047f89SShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 243882b0f8c3SJan Kara if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) 243982b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 244082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 24414e047f89SShachar Raindel } 24424e047f89SShachar Raindel 24434e047f89SShachar Raindel /* 24442f38ab2cSShachar Raindel * Handle the case of a page which we actually need to copy to a new page. 24452f38ab2cSShachar Raindel * 24462f38ab2cSShachar Raindel * Called with mmap_sem locked and the old page referenced, but 24472f38ab2cSShachar Raindel * without the ptl held. 24482f38ab2cSShachar Raindel * 24492f38ab2cSShachar Raindel * High level logic flow: 24502f38ab2cSShachar Raindel * 24512f38ab2cSShachar Raindel * - Allocate a page, copy the content of the old page to the new one. 24522f38ab2cSShachar Raindel * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. 24532f38ab2cSShachar Raindel * - Take the PTL. If the pte changed, bail out and release the allocated page 24542f38ab2cSShachar Raindel * - If the pte is still the way we remember it, update the page table and all 24552f38ab2cSShachar Raindel * relevant references. This includes dropping the reference the page-table 24562f38ab2cSShachar Raindel * held to the old page, as well as updating the rmap. 24572f38ab2cSShachar Raindel * - In any case, unlock the PTL and drop the reference we took to the old page. 24582f38ab2cSShachar Raindel */ 2459a41b70d6SJan Kara static int wp_page_copy(struct vm_fault *vmf) 24602f38ab2cSShachar Raindel { 246182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2462bae473a4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 2463a41b70d6SJan Kara struct page *old_page = vmf->page; 24642f38ab2cSShachar Raindel struct page *new_page = NULL; 24652f38ab2cSShachar Raindel pte_t entry; 24662f38ab2cSShachar Raindel int page_copied = 0; 246782b0f8c3SJan Kara const unsigned long mmun_start = vmf->address & PAGE_MASK; 2468bae473a4SKirill A. Shutemov const unsigned long mmun_end = mmun_start + PAGE_SIZE; 24692f38ab2cSShachar Raindel struct mem_cgroup *memcg; 24702f38ab2cSShachar Raindel 24712f38ab2cSShachar Raindel if (unlikely(anon_vma_prepare(vma))) 24722f38ab2cSShachar Raindel goto oom; 24732f38ab2cSShachar Raindel 24742994302bSJan Kara if (is_zero_pfn(pte_pfn(vmf->orig_pte))) { 247582b0f8c3SJan Kara new_page = alloc_zeroed_user_highpage_movable(vma, 247682b0f8c3SJan Kara vmf->address); 24772f38ab2cSShachar Raindel if (!new_page) 24782f38ab2cSShachar Raindel goto oom; 24792f38ab2cSShachar Raindel } else { 2480bae473a4SKirill A. Shutemov new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 248182b0f8c3SJan Kara vmf->address); 24822f38ab2cSShachar Raindel if (!new_page) 24832f38ab2cSShachar Raindel goto oom; 248482b0f8c3SJan Kara cow_user_page(new_page, old_page, vmf->address, vma); 24852f38ab2cSShachar Raindel } 24862f38ab2cSShachar Raindel 2487f627c2f5SKirill A. Shutemov if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg, false)) 24882f38ab2cSShachar Raindel goto oom_free_new; 24892f38ab2cSShachar Raindel 2490eb3c24f3SMel Gorman __SetPageUptodate(new_page); 2491eb3c24f3SMel Gorman 24922f38ab2cSShachar Raindel mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 24932f38ab2cSShachar Raindel 24942f38ab2cSShachar Raindel /* 24952f38ab2cSShachar Raindel * Re-check the pte - we dropped the lock 24962f38ab2cSShachar Raindel */ 249782b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); 24982994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { 24992f38ab2cSShachar Raindel if (old_page) { 25002f38ab2cSShachar Raindel if (!PageAnon(old_page)) { 2501eca56ff9SJerome Marchand dec_mm_counter_fast(mm, 2502eca56ff9SJerome Marchand mm_counter_file(old_page)); 25032f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 25042f38ab2cSShachar Raindel } 25052f38ab2cSShachar Raindel } else { 25062f38ab2cSShachar Raindel inc_mm_counter_fast(mm, MM_ANONPAGES); 25072f38ab2cSShachar Raindel } 25082994302bSJan Kara flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); 25092f38ab2cSShachar Raindel entry = mk_pte(new_page, vma->vm_page_prot); 25102f38ab2cSShachar Raindel entry = maybe_mkwrite(pte_mkdirty(entry), vma); 25112f38ab2cSShachar Raindel /* 25122f38ab2cSShachar Raindel * Clear the pte entry and flush it first, before updating the 25132f38ab2cSShachar Raindel * pte with the new entry. This will avoid a race condition 25142f38ab2cSShachar Raindel * seen in the presence of one thread doing SMC and another 25152f38ab2cSShachar Raindel * thread doing COW. 25162f38ab2cSShachar Raindel */ 251782b0f8c3SJan Kara ptep_clear_flush_notify(vma, vmf->address, vmf->pte); 251882b0f8c3SJan Kara page_add_new_anon_rmap(new_page, vma, vmf->address, false); 2519f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(new_page, memcg, false, false); 25202f38ab2cSShachar Raindel lru_cache_add_active_or_unevictable(new_page, vma); 25212f38ab2cSShachar Raindel /* 25222f38ab2cSShachar Raindel * We call the notify macro here because, when using secondary 25232f38ab2cSShachar Raindel * mmu page tables (such as kvm shadow page tables), we want the 25242f38ab2cSShachar Raindel * new page to be mapped directly into the secondary page table. 25252f38ab2cSShachar Raindel */ 252682b0f8c3SJan Kara set_pte_at_notify(mm, vmf->address, vmf->pte, entry); 252782b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 25282f38ab2cSShachar Raindel if (old_page) { 25292f38ab2cSShachar Raindel /* 25302f38ab2cSShachar Raindel * Only after switching the pte to the new page may 25312f38ab2cSShachar Raindel * we remove the mapcount here. Otherwise another 25322f38ab2cSShachar Raindel * process may come and find the rmap count decremented 25332f38ab2cSShachar Raindel * before the pte is switched to the new page, and 25342f38ab2cSShachar Raindel * "reuse" the old page writing into it while our pte 25352f38ab2cSShachar Raindel * here still points into it and can be read by other 25362f38ab2cSShachar Raindel * threads. 25372f38ab2cSShachar Raindel * 25382f38ab2cSShachar Raindel * The critical issue is to order this 25392f38ab2cSShachar Raindel * page_remove_rmap with the ptp_clear_flush above. 25402f38ab2cSShachar Raindel * Those stores are ordered by (if nothing else,) 25412f38ab2cSShachar Raindel * the barrier present in the atomic_add_negative 25422f38ab2cSShachar Raindel * in page_remove_rmap. 25432f38ab2cSShachar Raindel * 25442f38ab2cSShachar Raindel * Then the TLB flush in ptep_clear_flush ensures that 25452f38ab2cSShachar Raindel * no process can access the old page before the 25462f38ab2cSShachar Raindel * decremented mapcount is visible. And the old page 25472f38ab2cSShachar Raindel * cannot be reused until after the decremented 25482f38ab2cSShachar Raindel * mapcount is visible. So transitively, TLBs to 25492f38ab2cSShachar Raindel * old page will be flushed before it can be reused. 25502f38ab2cSShachar Raindel */ 2551d281ee61SKirill A. Shutemov page_remove_rmap(old_page, false); 25522f38ab2cSShachar Raindel } 25532f38ab2cSShachar Raindel 25542f38ab2cSShachar Raindel /* Free the old page.. */ 25552f38ab2cSShachar Raindel new_page = old_page; 25562f38ab2cSShachar Raindel page_copied = 1; 25572f38ab2cSShachar Raindel } else { 2558f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(new_page, memcg, false); 25592f38ab2cSShachar Raindel } 25602f38ab2cSShachar Raindel 25612f38ab2cSShachar Raindel if (new_page) 256209cbfeafSKirill A. Shutemov put_page(new_page); 25632f38ab2cSShachar Raindel 256482b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 25654645b9feSJérôme Glisse /* 25664645b9feSJérôme Glisse * No need to double call mmu_notifier->invalidate_range() callback as 25674645b9feSJérôme Glisse * the above ptep_clear_flush_notify() did already call it. 25684645b9feSJérôme Glisse */ 25694645b9feSJérôme Glisse mmu_notifier_invalidate_range_only_end(mm, mmun_start, mmun_end); 25702f38ab2cSShachar Raindel if (old_page) { 25712f38ab2cSShachar Raindel /* 25722f38ab2cSShachar Raindel * Don't let another task, with possibly unlocked vma, 25732f38ab2cSShachar Raindel * keep the mlocked page. 25742f38ab2cSShachar Raindel */ 25752f38ab2cSShachar Raindel if (page_copied && (vma->vm_flags & VM_LOCKED)) { 25762f38ab2cSShachar Raindel lock_page(old_page); /* LRU manipulation */ 2577e90309c9SKirill A. Shutemov if (PageMlocked(old_page)) 25782f38ab2cSShachar Raindel munlock_vma_page(old_page); 25792f38ab2cSShachar Raindel unlock_page(old_page); 25802f38ab2cSShachar Raindel } 258109cbfeafSKirill A. Shutemov put_page(old_page); 25822f38ab2cSShachar Raindel } 25832f38ab2cSShachar Raindel return page_copied ? VM_FAULT_WRITE : 0; 25842f38ab2cSShachar Raindel oom_free_new: 258509cbfeafSKirill A. Shutemov put_page(new_page); 25862f38ab2cSShachar Raindel oom: 25872f38ab2cSShachar Raindel if (old_page) 258809cbfeafSKirill A. Shutemov put_page(old_page); 25892f38ab2cSShachar Raindel return VM_FAULT_OOM; 25902f38ab2cSShachar Raindel } 25912f38ab2cSShachar Raindel 259266a6197cSJan Kara /** 259366a6197cSJan Kara * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE 259466a6197cSJan Kara * writeable once the page is prepared 259566a6197cSJan Kara * 259666a6197cSJan Kara * @vmf: structure describing the fault 259766a6197cSJan Kara * 259866a6197cSJan Kara * This function handles all that is needed to finish a write page fault in a 259966a6197cSJan Kara * shared mapping due to PTE being read-only once the mapped page is prepared. 260066a6197cSJan Kara * It handles locking of PTE and modifying it. The function returns 260166a6197cSJan Kara * VM_FAULT_WRITE on success, 0 when PTE got changed before we acquired PTE 260266a6197cSJan Kara * lock. 260366a6197cSJan Kara * 260466a6197cSJan Kara * The function expects the page to be locked or other protection against 260566a6197cSJan Kara * concurrent faults / writeback (such as DAX radix tree locks). 260666a6197cSJan Kara */ 260766a6197cSJan Kara int finish_mkwrite_fault(struct vm_fault *vmf) 260866a6197cSJan Kara { 260966a6197cSJan Kara WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); 261066a6197cSJan Kara vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, 261166a6197cSJan Kara &vmf->ptl); 261266a6197cSJan Kara /* 261366a6197cSJan Kara * We might have raced with another page fault while we released the 261466a6197cSJan Kara * pte_offset_map_lock. 261566a6197cSJan Kara */ 261666a6197cSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 261766a6197cSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2618a19e2553SJan Kara return VM_FAULT_NOPAGE; 261966a6197cSJan Kara } 262066a6197cSJan Kara wp_page_reuse(vmf); 2621a19e2553SJan Kara return 0; 262266a6197cSJan Kara } 262366a6197cSJan Kara 2624dd906184SBoaz Harrosh /* 2625dd906184SBoaz Harrosh * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED 2626dd906184SBoaz Harrosh * mapping 2627dd906184SBoaz Harrosh */ 26282994302bSJan Kara static int wp_pfn_shared(struct vm_fault *vmf) 2629dd906184SBoaz Harrosh { 263082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 2631bae473a4SKirill A. Shutemov 2632dd906184SBoaz Harrosh if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { 2633dd906184SBoaz Harrosh int ret; 2634dd906184SBoaz Harrosh 263582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2636fe82221fSJan Kara vmf->flags |= FAULT_FLAG_MKWRITE; 263711bac800SDave Jiang ret = vma->vm_ops->pfn_mkwrite(vmf); 26382f89dc12SJan Kara if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) 2639dd906184SBoaz Harrosh return ret; 264066a6197cSJan Kara return finish_mkwrite_fault(vmf); 2641dd906184SBoaz Harrosh } 2642997dd98dSJan Kara wp_page_reuse(vmf); 2643997dd98dSJan Kara return VM_FAULT_WRITE; 2644dd906184SBoaz Harrosh } 2645dd906184SBoaz Harrosh 2646a41b70d6SJan Kara static int wp_page_shared(struct vm_fault *vmf) 264782b0f8c3SJan Kara __releases(vmf->ptl) 264893e478d4SShachar Raindel { 264982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 265093e478d4SShachar Raindel 2651a41b70d6SJan Kara get_page(vmf->page); 265293e478d4SShachar Raindel 265393e478d4SShachar Raindel if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 265493e478d4SShachar Raindel int tmp; 265593e478d4SShachar Raindel 265682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 265738b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 265893e478d4SShachar Raindel if (unlikely(!tmp || (tmp & 265993e478d4SShachar Raindel (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 2660a41b70d6SJan Kara put_page(vmf->page); 266193e478d4SShachar Raindel return tmp; 266293e478d4SShachar Raindel } 266366a6197cSJan Kara tmp = finish_mkwrite_fault(vmf); 2664a19e2553SJan Kara if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 2665a41b70d6SJan Kara unlock_page(vmf->page); 2666a41b70d6SJan Kara put_page(vmf->page); 266766a6197cSJan Kara return tmp; 266893e478d4SShachar Raindel } 266966a6197cSJan Kara } else { 2670997dd98dSJan Kara wp_page_reuse(vmf); 2671997dd98dSJan Kara lock_page(vmf->page); 267293e478d4SShachar Raindel } 2673997dd98dSJan Kara fault_dirty_shared_page(vma, vmf->page); 2674997dd98dSJan Kara put_page(vmf->page); 267593e478d4SShachar Raindel 2676997dd98dSJan Kara return VM_FAULT_WRITE; 267793e478d4SShachar Raindel } 267893e478d4SShachar Raindel 26792f38ab2cSShachar Raindel /* 26801da177e4SLinus Torvalds * This routine handles present pages, when users try to write 26811da177e4SLinus Torvalds * to a shared page. It is done by copying the page to a new address 26821da177e4SLinus Torvalds * and decrementing the shared-page counter for the old page. 26831da177e4SLinus Torvalds * 26841da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 26851da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 26861da177e4SLinus Torvalds * Thus we can safely just mark it writable once we've done any necessary 26871da177e4SLinus Torvalds * COW. 26881da177e4SLinus Torvalds * 26891da177e4SLinus Torvalds * We also mark the page dirty at this point even though the page will 26901da177e4SLinus Torvalds * change only once the write actually happens. This avoids a few races, 26911da177e4SLinus Torvalds * and potentially makes it more efficient. 26921da177e4SLinus Torvalds * 26938f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 26948f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 26958f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 26961da177e4SLinus Torvalds */ 26972994302bSJan Kara static int do_wp_page(struct vm_fault *vmf) 269882b0f8c3SJan Kara __releases(vmf->ptl) 26991da177e4SLinus Torvalds { 270082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 27011da177e4SLinus Torvalds 2702a41b70d6SJan Kara vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte); 2703a41b70d6SJan Kara if (!vmf->page) { 2704251b97f5SPeter Zijlstra /* 270564e45507SPeter Feiner * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a 270664e45507SPeter Feiner * VM_PFNMAP VMA. 2707251b97f5SPeter Zijlstra * 2708251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 2709dd906184SBoaz Harrosh * Just mark the pages writable and/or call ops->pfn_mkwrite. 2710251b97f5SPeter Zijlstra */ 2711251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 2712251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 27132994302bSJan Kara return wp_pfn_shared(vmf); 27142f38ab2cSShachar Raindel 271582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2716a41b70d6SJan Kara return wp_page_copy(vmf); 2717251b97f5SPeter Zijlstra } 27181da177e4SLinus Torvalds 2719d08b3851SPeter Zijlstra /* 2720ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 2721ee6a6457SPeter Zijlstra * not dirty accountable. 2722d08b3851SPeter Zijlstra */ 2723a41b70d6SJan Kara if (PageAnon(vmf->page) && !PageKsm(vmf->page)) { 2724ba3c4ce6SHuang Ying int total_map_swapcount; 2725a41b70d6SJan Kara if (!trylock_page(vmf->page)) { 2726a41b70d6SJan Kara get_page(vmf->page); 272782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2728a41b70d6SJan Kara lock_page(vmf->page); 272982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 273082b0f8c3SJan Kara vmf->address, &vmf->ptl); 27312994302bSJan Kara if (!pte_same(*vmf->pte, vmf->orig_pte)) { 2732a41b70d6SJan Kara unlock_page(vmf->page); 273382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2734a41b70d6SJan Kara put_page(vmf->page); 273528766805SShachar Raindel return 0; 2736ab967d86SHugh Dickins } 2737a41b70d6SJan Kara put_page(vmf->page); 2738ab967d86SHugh Dickins } 2739ba3c4ce6SHuang Ying if (reuse_swap_page(vmf->page, &total_map_swapcount)) { 2740ba3c4ce6SHuang Ying if (total_map_swapcount == 1) { 2741c44b6743SRik van Riel /* 27426d0a07edSAndrea Arcangeli * The page is all ours. Move it to 27436d0a07edSAndrea Arcangeli * our anon_vma so the rmap code will 27446d0a07edSAndrea Arcangeli * not search our parent or siblings. 27456d0a07edSAndrea Arcangeli * Protected against the rmap code by 27466d0a07edSAndrea Arcangeli * the page lock. 2747c44b6743SRik van Riel */ 2748a41b70d6SJan Kara page_move_anon_rmap(vmf->page, vma); 27496d0a07edSAndrea Arcangeli } 2750a41b70d6SJan Kara unlock_page(vmf->page); 2751997dd98dSJan Kara wp_page_reuse(vmf); 2752997dd98dSJan Kara return VM_FAULT_WRITE; 2753b009c024SMichel Lespinasse } 2754a41b70d6SJan Kara unlock_page(vmf->page); 2755ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 2756d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 2757a41b70d6SJan Kara return wp_page_shared(vmf); 27581da177e4SLinus Torvalds } 27591da177e4SLinus Torvalds 27601da177e4SLinus Torvalds /* 27611da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 27621da177e4SLinus Torvalds */ 2763a41b70d6SJan Kara get_page(vmf->page); 276428766805SShachar Raindel 276582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 2766a41b70d6SJan Kara return wp_page_copy(vmf); 27671da177e4SLinus Torvalds } 27681da177e4SLinus Torvalds 276997a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 27701da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 27711da177e4SLinus Torvalds struct zap_details *details) 27721da177e4SLinus Torvalds { 2773f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 27741da177e4SLinus Torvalds } 27751da177e4SLinus Torvalds 2776f808c13fSDavidlohr Bueso static inline void unmap_mapping_range_tree(struct rb_root_cached *root, 27771da177e4SLinus Torvalds struct zap_details *details) 27781da177e4SLinus Torvalds { 27791da177e4SLinus Torvalds struct vm_area_struct *vma; 27801da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 27811da177e4SLinus Torvalds 27826b2dbba8SMichel Lespinasse vma_interval_tree_foreach(vma, root, 27831da177e4SLinus Torvalds details->first_index, details->last_index) { 27841da177e4SLinus Torvalds 27851da177e4SLinus Torvalds vba = vma->vm_pgoff; 2786d6e93217SLibin vea = vba + vma_pages(vma) - 1; 27871da177e4SLinus Torvalds zba = details->first_index; 27881da177e4SLinus Torvalds if (zba < vba) 27891da177e4SLinus Torvalds zba = vba; 27901da177e4SLinus Torvalds zea = details->last_index; 27911da177e4SLinus Torvalds if (zea > vea) 27921da177e4SLinus Torvalds zea = vea; 27931da177e4SLinus Torvalds 279497a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 27951da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 27961da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 279797a89413SPeter Zijlstra details); 27981da177e4SLinus Torvalds } 27991da177e4SLinus Torvalds } 28001da177e4SLinus Torvalds 28011da177e4SLinus Torvalds /** 2802*977fbdcdSMatthew Wilcox * unmap_mapping_pages() - Unmap pages from processes. 2803*977fbdcdSMatthew Wilcox * @mapping: The address space containing pages to be unmapped. 2804*977fbdcdSMatthew Wilcox * @start: Index of first page to be unmapped. 2805*977fbdcdSMatthew Wilcox * @nr: Number of pages to be unmapped. 0 to unmap to end of file. 2806*977fbdcdSMatthew Wilcox * @even_cows: Whether to unmap even private COWed pages. 2807*977fbdcdSMatthew Wilcox * 2808*977fbdcdSMatthew Wilcox * Unmap the pages in this address space from any userspace process which 2809*977fbdcdSMatthew Wilcox * has them mmaped. Generally, you want to remove COWed pages as well when 2810*977fbdcdSMatthew Wilcox * a file is being truncated, but not when invalidating pages from the page 2811*977fbdcdSMatthew Wilcox * cache. 2812*977fbdcdSMatthew Wilcox */ 2813*977fbdcdSMatthew Wilcox void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, 2814*977fbdcdSMatthew Wilcox pgoff_t nr, bool even_cows) 2815*977fbdcdSMatthew Wilcox { 2816*977fbdcdSMatthew Wilcox struct zap_details details = { }; 2817*977fbdcdSMatthew Wilcox 2818*977fbdcdSMatthew Wilcox details.check_mapping = even_cows ? NULL : mapping; 2819*977fbdcdSMatthew Wilcox details.first_index = start; 2820*977fbdcdSMatthew Wilcox details.last_index = start + nr - 1; 2821*977fbdcdSMatthew Wilcox if (details.last_index < details.first_index) 2822*977fbdcdSMatthew Wilcox details.last_index = ULONG_MAX; 2823*977fbdcdSMatthew Wilcox 2824*977fbdcdSMatthew Wilcox i_mmap_lock_write(mapping); 2825*977fbdcdSMatthew Wilcox if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) 2826*977fbdcdSMatthew Wilcox unmap_mapping_range_tree(&mapping->i_mmap, &details); 2827*977fbdcdSMatthew Wilcox i_mmap_unlock_write(mapping); 2828*977fbdcdSMatthew Wilcox } 2829*977fbdcdSMatthew Wilcox 2830*977fbdcdSMatthew Wilcox /** 28318a5f14a2SKirill A. Shutemov * unmap_mapping_range - unmap the portion of all mmaps in the specified 2832*977fbdcdSMatthew Wilcox * address_space corresponding to the specified byte range in the underlying 28338a5f14a2SKirill A. Shutemov * file. 28348a5f14a2SKirill A. Shutemov * 28353d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 28361da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 28371da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 283825d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 28391da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 28401da177e4SLinus Torvalds * partial pages. 28411da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 28421da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 28431da177e4SLinus Torvalds * end of the file. 28441da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 28451da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 28461da177e4SLinus Torvalds */ 28471da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 28481da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 28491da177e4SLinus Torvalds { 28501da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 28511da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 28521da177e4SLinus Torvalds 28531da177e4SLinus Torvalds /* Check for overflow. */ 28541da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 28551da177e4SLinus Torvalds long long holeend = 28561da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 28571da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 28581da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 28591da177e4SLinus Torvalds } 28601da177e4SLinus Torvalds 2861*977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, hba, hlen, even_cows); 28621da177e4SLinus Torvalds } 28631da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 28641da177e4SLinus Torvalds 28651da177e4SLinus Torvalds /* 28668f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 28678f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 28689a95f3cfSPaul Cassella * We return with pte unmapped and unlocked. 28699a95f3cfSPaul Cassella * 28709a95f3cfSPaul Cassella * We return with the mmap_sem locked or unlocked in the same cases 28719a95f3cfSPaul Cassella * as does filemap_fault(). 28721da177e4SLinus Torvalds */ 28732994302bSJan Kara int do_swap_page(struct vm_fault *vmf) 28741da177e4SLinus Torvalds { 287582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 28760bcac06fSMinchan Kim struct page *page = NULL, *swapcache = NULL; 287700501b53SJohannes Weiner struct mem_cgroup *memcg; 2878ec560175SHuang Ying struct vma_swap_readahead swap_ra; 287965500d23SHugh Dickins swp_entry_t entry; 28801da177e4SLinus Torvalds pte_t pte; 2881d065bd81SMichel Lespinasse int locked; 2882ad8c2ee8SRik van Riel int exclusive = 0; 288383c54070SNick Piggin int ret = 0; 2884ec560175SHuang Ying bool vma_readahead = swap_use_vma_readahead(); 28851da177e4SLinus Torvalds 2886f8020772SMinchan Kim if (vma_readahead) { 2887ec560175SHuang Ying page = swap_readahead_detect(vmf, &swap_ra); 2888f8020772SMinchan Kim swapcache = page; 2889f8020772SMinchan Kim } 2890f8020772SMinchan Kim 2891ec560175SHuang Ying if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte)) { 2892ec560175SHuang Ying if (page) 2893ec560175SHuang Ying put_page(page); 28948f4e2101SHugh Dickins goto out; 2895ec560175SHuang Ying } 289665500d23SHugh Dickins 28972994302bSJan Kara entry = pte_to_swp_entry(vmf->orig_pte); 2898d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 28990697212aSChristoph Lameter if (is_migration_entry(entry)) { 290082b0f8c3SJan Kara migration_entry_wait(vma->vm_mm, vmf->pmd, 290182b0f8c3SJan Kara vmf->address); 29025042db43SJérôme Glisse } else if (is_device_private_entry(entry)) { 29035042db43SJérôme Glisse /* 29045042db43SJérôme Glisse * For un-addressable device memory we call the pgmap 29055042db43SJérôme Glisse * fault handler callback. The callback must migrate 29065042db43SJérôme Glisse * the page back to some CPU accessible page. 29075042db43SJérôme Glisse */ 29085042db43SJérôme Glisse ret = device_private_entry_fault(vma, vmf->address, entry, 29095042db43SJérôme Glisse vmf->flags, vmf->pmd); 2910d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 2911d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 2912d1737fdbSAndi Kleen } else { 29132994302bSJan Kara print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); 2914d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 2915d1737fdbSAndi Kleen } 29160697212aSChristoph Lameter goto out; 29170697212aSChristoph Lameter } 29180bcac06fSMinchan Kim 29190bcac06fSMinchan Kim 29200ff92245SShailabh Nagar delayacct_set_flag(DELAYACCT_PF_SWAPIN); 2921f8020772SMinchan Kim if (!page) { 2922ec560175SHuang Ying page = lookup_swap_cache(entry, vma_readahead ? vma : NULL, 292382b0f8c3SJan Kara vmf->address); 2924f8020772SMinchan Kim swapcache = page; 2925f8020772SMinchan Kim } 2926f8020772SMinchan Kim 29271da177e4SLinus Torvalds if (!page) { 29280bcac06fSMinchan Kim struct swap_info_struct *si = swp_swap_info(entry); 29290bcac06fSMinchan Kim 2930aa8d22a1SMinchan Kim if (si->flags & SWP_SYNCHRONOUS_IO && 2931aa8d22a1SMinchan Kim __swap_count(si, entry) == 1) { 29320bcac06fSMinchan Kim /* skip swapcache */ 29330bcac06fSMinchan Kim page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 29340bcac06fSMinchan Kim if (page) { 29350bcac06fSMinchan Kim __SetPageLocked(page); 29360bcac06fSMinchan Kim __SetPageSwapBacked(page); 29370bcac06fSMinchan Kim set_page_private(page, entry.val); 29380bcac06fSMinchan Kim lru_cache_add_anon(page); 29390bcac06fSMinchan Kim swap_readpage(page, true); 29400bcac06fSMinchan Kim } 2941aa8d22a1SMinchan Kim } else { 2942aa8d22a1SMinchan Kim if (vma_readahead) 2943aa8d22a1SMinchan Kim page = do_swap_page_readahead(entry, 2944aa8d22a1SMinchan Kim GFP_HIGHUSER_MOVABLE, vmf, &swap_ra); 2945aa8d22a1SMinchan Kim else 2946aa8d22a1SMinchan Kim page = swapin_readahead(entry, 2947aa8d22a1SMinchan Kim GFP_HIGHUSER_MOVABLE, vma, vmf->address); 2948aa8d22a1SMinchan Kim swapcache = page; 29490bcac06fSMinchan Kim } 29500bcac06fSMinchan Kim 2951ec560175SHuang Ying if (!page) { 29521da177e4SLinus Torvalds /* 29538f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 29548f4e2101SHugh Dickins * while we released the pte lock. 29551da177e4SLinus Torvalds */ 295682b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 295782b0f8c3SJan Kara vmf->address, &vmf->ptl); 29582994302bSJan Kara if (likely(pte_same(*vmf->pte, vmf->orig_pte))) 29591da177e4SLinus Torvalds ret = VM_FAULT_OOM; 29600ff92245SShailabh Nagar delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 296165500d23SHugh Dickins goto unlock; 29621da177e4SLinus Torvalds } 29631da177e4SLinus Torvalds 29641da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 29651da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 2966f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 29672262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 2968d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 296971f72525SWu Fengguang /* 297071f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 297171f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 297271f72525SWu Fengguang */ 2973d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 2974d1737fdbSAndi Kleen delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 297556f31801SHugh Dickins swapcache = page; 29764779cb31SAndi Kleen goto out_release; 29771da177e4SLinus Torvalds } 29781da177e4SLinus Torvalds 297982b0f8c3SJan Kara locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); 2980e709ffd6SRik van Riel 298120a1022dSBalbir Singh delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 2982d065bd81SMichel Lespinasse if (!locked) { 2983d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 2984d065bd81SMichel Lespinasse goto out_release; 2985d065bd81SMichel Lespinasse } 29861da177e4SLinus Torvalds 29874969c119SAndrea Arcangeli /* 298831c4a3d3SHugh Dickins * Make sure try_to_free_swap or reuse_swap_page or swapoff did not 298931c4a3d3SHugh Dickins * release the swapcache from under us. The page pin, and pte_same 299031c4a3d3SHugh Dickins * test below, are not enough to exclude that. Even if it is still 299131c4a3d3SHugh Dickins * swapcache, we need to check that the page's swap has not changed. 29924969c119SAndrea Arcangeli */ 29930bcac06fSMinchan Kim if (unlikely((!PageSwapCache(page) || 29940bcac06fSMinchan Kim page_private(page) != entry.val)) && swapcache) 29954969c119SAndrea Arcangeli goto out_page; 29964969c119SAndrea Arcangeli 299782b0f8c3SJan Kara page = ksm_might_need_to_copy(page, vma, vmf->address); 29984969c119SAndrea Arcangeli if (unlikely(!page)) { 29995ad64688SHugh Dickins ret = VM_FAULT_OOM; 30004969c119SAndrea Arcangeli page = swapcache; 30014969c119SAndrea Arcangeli goto out_page; 30024969c119SAndrea Arcangeli } 30035ad64688SHugh Dickins 3004bae473a4SKirill A. Shutemov if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, 3005bae473a4SKirill A. Shutemov &memcg, false)) { 3006073e587eSKAMEZAWA Hiroyuki ret = VM_FAULT_OOM; 3007bc43f75cSJohannes Weiner goto out_page; 3008073e587eSKAMEZAWA Hiroyuki } 3009073e587eSKAMEZAWA Hiroyuki 30101da177e4SLinus Torvalds /* 30118f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 30121da177e4SLinus Torvalds */ 301382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 301482b0f8c3SJan Kara &vmf->ptl); 30152994302bSJan Kara if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) 3016b8107480SKirill Korotaev goto out_nomap; 3017b8107480SKirill Korotaev 3018b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3019b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3020b8107480SKirill Korotaev goto out_nomap; 30211da177e4SLinus Torvalds } 30221da177e4SLinus Torvalds 30238c7c6e34SKAMEZAWA Hiroyuki /* 30248c7c6e34SKAMEZAWA Hiroyuki * The page isn't present yet, go ahead with the fault. 30258c7c6e34SKAMEZAWA Hiroyuki * 30268c7c6e34SKAMEZAWA Hiroyuki * Be careful about the sequence of operations here. 30278c7c6e34SKAMEZAWA Hiroyuki * To get its accounting right, reuse_swap_page() must be called 30288c7c6e34SKAMEZAWA Hiroyuki * while the page is counted on swap but not yet in mapcount i.e. 30298c7c6e34SKAMEZAWA Hiroyuki * before page_add_anon_rmap() and swap_free(); try_to_free_swap() 30308c7c6e34SKAMEZAWA Hiroyuki * must be called after the swap_free(), or it will never succeed. 30318c7c6e34SKAMEZAWA Hiroyuki */ 30321da177e4SLinus Torvalds 3033bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 3034bae473a4SKirill A. Shutemov dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); 30351da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 303682b0f8c3SJan Kara if ((vmf->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) { 30371da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 303882b0f8c3SJan Kara vmf->flags &= ~FAULT_FLAG_WRITE; 30399a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 3040d281ee61SKirill A. Shutemov exclusive = RMAP_EXCLUSIVE; 30411da177e4SLinus Torvalds } 30421da177e4SLinus Torvalds flush_icache_page(vma, page); 30432994302bSJan Kara if (pte_swp_soft_dirty(vmf->orig_pte)) 3044179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 304582b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); 30462994302bSJan Kara vmf->orig_pte = pte; 30470bcac06fSMinchan Kim 30480bcac06fSMinchan Kim /* ksm created a completely new copy */ 30490bcac06fSMinchan Kim if (unlikely(page != swapcache && swapcache)) { 305082b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3051f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, false); 305200501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 30530bcac06fSMinchan Kim } else { 30540bcac06fSMinchan Kim do_page_add_anon_rmap(page, vma, vmf->address, exclusive); 30550bcac06fSMinchan Kim mem_cgroup_commit_charge(page, memcg, true, false); 30560bcac06fSMinchan Kim activate_page(page); 305700501b53SJohannes Weiner } 30581da177e4SLinus Torvalds 3059c475a8abSHugh Dickins swap_free(entry); 30605ccc5abaSVladimir Davydov if (mem_cgroup_swap_full(page) || 30615ccc5abaSVladimir Davydov (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) 3062a2c43eedSHugh Dickins try_to_free_swap(page); 3063c475a8abSHugh Dickins unlock_page(page); 30640bcac06fSMinchan Kim if (page != swapcache && swapcache) { 30654969c119SAndrea Arcangeli /* 30664969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 30674969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 30684969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 30694969c119SAndrea Arcangeli * further safety release the lock after the swap_free 30704969c119SAndrea Arcangeli * so that the swap count won't change under a 30714969c119SAndrea Arcangeli * parallel locked swapcache. 30724969c119SAndrea Arcangeli */ 30734969c119SAndrea Arcangeli unlock_page(swapcache); 307409cbfeafSKirill A. Shutemov put_page(swapcache); 30754969c119SAndrea Arcangeli } 3076c475a8abSHugh Dickins 307782b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 30782994302bSJan Kara ret |= do_wp_page(vmf); 307961469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 308061469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 30811da177e4SLinus Torvalds goto out; 30821da177e4SLinus Torvalds } 30831da177e4SLinus Torvalds 30841da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 308582b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 308665500d23SHugh Dickins unlock: 308782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 30881da177e4SLinus Torvalds out: 30891da177e4SLinus Torvalds return ret; 3090b8107480SKirill Korotaev out_nomap: 3091f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, false); 309282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3093bc43f75cSJohannes Weiner out_page: 3094b8107480SKirill Korotaev unlock_page(page); 30954779cb31SAndi Kleen out_release: 309609cbfeafSKirill A. Shutemov put_page(page); 30970bcac06fSMinchan Kim if (page != swapcache && swapcache) { 30984969c119SAndrea Arcangeli unlock_page(swapcache); 309909cbfeafSKirill A. Shutemov put_page(swapcache); 31004969c119SAndrea Arcangeli } 310165500d23SHugh Dickins return ret; 31021da177e4SLinus Torvalds } 31031da177e4SLinus Torvalds 31041da177e4SLinus Torvalds /* 31058f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 31068f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 31078f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 31081da177e4SLinus Torvalds */ 310982b0f8c3SJan Kara static int do_anonymous_page(struct vm_fault *vmf) 31101da177e4SLinus Torvalds { 311182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 311200501b53SJohannes Weiner struct mem_cgroup *memcg; 31138f4e2101SHugh Dickins struct page *page; 31146b31d595SMichal Hocko int ret = 0; 31151da177e4SLinus Torvalds pte_t entry; 31161da177e4SLinus Torvalds 31176b7339f4SKirill A. Shutemov /* File mapping without ->vm_ops ? */ 31186b7339f4SKirill A. Shutemov if (vma->vm_flags & VM_SHARED) 31196b7339f4SKirill A. Shutemov return VM_FAULT_SIGBUS; 31206b7339f4SKirill A. Shutemov 31217267ec00SKirill A. Shutemov /* 31227267ec00SKirill A. Shutemov * Use pte_alloc() instead of pte_alloc_map(). We can't run 31237267ec00SKirill A. Shutemov * pte_offset_map() on pmds where a huge pmd might be created 31247267ec00SKirill A. Shutemov * from a different thread. 31257267ec00SKirill A. Shutemov * 31267267ec00SKirill A. Shutemov * pte_alloc_map() is safe to use under down_write(mmap_sem) or when 31277267ec00SKirill A. Shutemov * parallel threads are excluded by other means. 31287267ec00SKirill A. Shutemov * 31297267ec00SKirill A. Shutemov * Here we only have down_read(mmap_sem). 31307267ec00SKirill A. Shutemov */ 313182b0f8c3SJan Kara if (pte_alloc(vma->vm_mm, vmf->pmd, vmf->address)) 31327267ec00SKirill A. Shutemov return VM_FAULT_OOM; 31337267ec00SKirill A. Shutemov 31347267ec00SKirill A. Shutemov /* See the comment in pte_alloc_one_map() */ 313582b0f8c3SJan Kara if (unlikely(pmd_trans_unstable(vmf->pmd))) 31367267ec00SKirill A. Shutemov return 0; 31377267ec00SKirill A. Shutemov 313811ac5524SLinus Torvalds /* Use the zero-page for reads */ 313982b0f8c3SJan Kara if (!(vmf->flags & FAULT_FLAG_WRITE) && 3140bae473a4SKirill A. Shutemov !mm_forbids_zeropage(vma->vm_mm)) { 314182b0f8c3SJan Kara entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), 314262eede62SHugh Dickins vma->vm_page_prot)); 314382b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, 314482b0f8c3SJan Kara vmf->address, &vmf->ptl); 314582b0f8c3SJan Kara if (!pte_none(*vmf->pte)) 3146a13ea5b7SHugh Dickins goto unlock; 31476b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 31486b31d595SMichal Hocko if (ret) 31496b31d595SMichal Hocko goto unlock; 31506b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 31516b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 315282b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 315382b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 31546b251fc9SAndrea Arcangeli } 3155a13ea5b7SHugh Dickins goto setpte; 3156a13ea5b7SHugh Dickins } 3157a13ea5b7SHugh Dickins 31581da177e4SLinus Torvalds /* Allocate our own private page. */ 31591da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 316065500d23SHugh Dickins goto oom; 316182b0f8c3SJan Kara page = alloc_zeroed_user_highpage_movable(vma, vmf->address); 31621da177e4SLinus Torvalds if (!page) 316365500d23SHugh Dickins goto oom; 3164eb3c24f3SMel Gorman 3165bae473a4SKirill A. Shutemov if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, &memcg, false)) 3166eb3c24f3SMel Gorman goto oom_free_page; 3167eb3c24f3SMel Gorman 316852f37629SMinchan Kim /* 316952f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 317052f37629SMinchan Kim * preceeding stores to the page contents become visible before 317152f37629SMinchan Kim * the set_pte_at() write. 317252f37629SMinchan Kim */ 31730ed361deSNick Piggin __SetPageUptodate(page); 31741da177e4SLinus Torvalds 317565500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 31761ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 31771ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 31788f4e2101SHugh Dickins 317982b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 318082b0f8c3SJan Kara &vmf->ptl); 318182b0f8c3SJan Kara if (!pte_none(*vmf->pte)) 31828f4e2101SHugh Dickins goto release; 31839ba69294SHugh Dickins 31846b31d595SMichal Hocko ret = check_stable_address_space(vma->vm_mm); 31856b31d595SMichal Hocko if (ret) 31866b31d595SMichal Hocko goto release; 31876b31d595SMichal Hocko 31886b251fc9SAndrea Arcangeli /* Deliver the page fault to userland, check inside PT lock */ 31896b251fc9SAndrea Arcangeli if (userfaultfd_missing(vma)) { 319082b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3191f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, false); 319209cbfeafSKirill A. Shutemov put_page(page); 319382b0f8c3SJan Kara return handle_userfault(vmf, VM_UFFD_MISSING); 31946b251fc9SAndrea Arcangeli } 31956b251fc9SAndrea Arcangeli 3196bae473a4SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 319782b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 3198f627c2f5SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, false); 319900501b53SJohannes Weiner lru_cache_add_active_or_unevictable(page, vma); 3200a13ea5b7SHugh Dickins setpte: 320182b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 32021da177e4SLinus Torvalds 32031da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 320482b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 320565500d23SHugh Dickins unlock: 320682b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 32076b31d595SMichal Hocko return ret; 32088f4e2101SHugh Dickins release: 3209f627c2f5SKirill A. Shutemov mem_cgroup_cancel_charge(page, memcg, false); 321009cbfeafSKirill A. Shutemov put_page(page); 32118f4e2101SHugh Dickins goto unlock; 32128a9f3ccdSBalbir Singh oom_free_page: 321309cbfeafSKirill A. Shutemov put_page(page); 321465500d23SHugh Dickins oom: 32151da177e4SLinus Torvalds return VM_FAULT_OOM; 32161da177e4SLinus Torvalds } 32171da177e4SLinus Torvalds 32189a95f3cfSPaul Cassella /* 32199a95f3cfSPaul Cassella * The mmap_sem must have been held on entry, and may have been 32209a95f3cfSPaul Cassella * released depending on flags and vma->vm_ops->fault() return value. 32219a95f3cfSPaul Cassella * See filemap_fault() and __lock_page_retry(). 32229a95f3cfSPaul Cassella */ 3223936ca80dSJan Kara static int __do_fault(struct vm_fault *vmf) 32247eae74afSKirill A. Shutemov { 322582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 32267eae74afSKirill A. Shutemov int ret; 32277eae74afSKirill A. Shutemov 322811bac800SDave Jiang ret = vma->vm_ops->fault(vmf); 32293917048dSJan Kara if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY | 3230b1aa812bSJan Kara VM_FAULT_DONE_COW))) 32317eae74afSKirill A. Shutemov return ret; 32327eae74afSKirill A. Shutemov 3233667240e0SJan Kara if (unlikely(PageHWPoison(vmf->page))) { 32347eae74afSKirill A. Shutemov if (ret & VM_FAULT_LOCKED) 3235667240e0SJan Kara unlock_page(vmf->page); 3236667240e0SJan Kara put_page(vmf->page); 3237936ca80dSJan Kara vmf->page = NULL; 32387eae74afSKirill A. Shutemov return VM_FAULT_HWPOISON; 32397eae74afSKirill A. Shutemov } 32407eae74afSKirill A. Shutemov 32417eae74afSKirill A. Shutemov if (unlikely(!(ret & VM_FAULT_LOCKED))) 3242667240e0SJan Kara lock_page(vmf->page); 32437eae74afSKirill A. Shutemov else 3244667240e0SJan Kara VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); 32457eae74afSKirill A. Shutemov 32467eae74afSKirill A. Shutemov return ret; 32477eae74afSKirill A. Shutemov } 32487eae74afSKirill A. Shutemov 3249d0f0931dSRoss Zwisler /* 3250d0f0931dSRoss Zwisler * The ordering of these checks is important for pmds with _PAGE_DEVMAP set. 3251d0f0931dSRoss Zwisler * If we check pmd_trans_unstable() first we will trip the bad_pmd() check 3252d0f0931dSRoss Zwisler * inside of pmd_none_or_trans_huge_or_clear_bad(). This will end up correctly 3253d0f0931dSRoss Zwisler * returning 1 but not before it spams dmesg with the pmd_clear_bad() output. 3254d0f0931dSRoss Zwisler */ 3255d0f0931dSRoss Zwisler static int pmd_devmap_trans_unstable(pmd_t *pmd) 3256d0f0931dSRoss Zwisler { 3257d0f0931dSRoss Zwisler return pmd_devmap(*pmd) || pmd_trans_unstable(pmd); 3258d0f0931dSRoss Zwisler } 3259d0f0931dSRoss Zwisler 326082b0f8c3SJan Kara static int pte_alloc_one_map(struct vm_fault *vmf) 32617267ec00SKirill A. Shutemov { 326282b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 32637267ec00SKirill A. Shutemov 326482b0f8c3SJan Kara if (!pmd_none(*vmf->pmd)) 32657267ec00SKirill A. Shutemov goto map_pte; 326682b0f8c3SJan Kara if (vmf->prealloc_pte) { 326782b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 326882b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) { 326982b0f8c3SJan Kara spin_unlock(vmf->ptl); 32707267ec00SKirill A. Shutemov goto map_pte; 32717267ec00SKirill A. Shutemov } 32727267ec00SKirill A. Shutemov 3273c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 327482b0f8c3SJan Kara pmd_populate(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 327582b0f8c3SJan Kara spin_unlock(vmf->ptl); 32767f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 327782b0f8c3SJan Kara } else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd, vmf->address))) { 32787267ec00SKirill A. Shutemov return VM_FAULT_OOM; 32797267ec00SKirill A. Shutemov } 32807267ec00SKirill A. Shutemov map_pte: 32817267ec00SKirill A. Shutemov /* 32827267ec00SKirill A. Shutemov * If a huge pmd materialized under us just retry later. Use 3283d0f0931dSRoss Zwisler * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead of 3284d0f0931dSRoss Zwisler * pmd_trans_huge() to ensure the pmd didn't become pmd_trans_huge 3285d0f0931dSRoss Zwisler * under us and then back to pmd_none, as a result of MADV_DONTNEED 3286d0f0931dSRoss Zwisler * running immediately after a huge pmd fault in a different thread of 3287d0f0931dSRoss Zwisler * this mm, in turn leading to a misleading pmd_trans_huge() retval. 3288d0f0931dSRoss Zwisler * All we have to ensure is that it is a regular pmd that we can walk 3289d0f0931dSRoss Zwisler * with pte_offset_map() and we can do that through an atomic read in 3290d0f0931dSRoss Zwisler * C, which is what pmd_trans_unstable() provides. 32917267ec00SKirill A. Shutemov */ 3292d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 32937267ec00SKirill A. Shutemov return VM_FAULT_NOPAGE; 32947267ec00SKirill A. Shutemov 3295d0f0931dSRoss Zwisler /* 3296d0f0931dSRoss Zwisler * At this point we know that our vmf->pmd points to a page of ptes 3297d0f0931dSRoss Zwisler * and it cannot become pmd_none(), pmd_devmap() or pmd_trans_huge() 3298d0f0931dSRoss Zwisler * for the duration of the fault. If a racing MADV_DONTNEED runs and 3299d0f0931dSRoss Zwisler * we zap the ptes pointed to by our vmf->pmd, the vmf->ptl will still 3300d0f0931dSRoss Zwisler * be valid and we will re-check to make sure the vmf->pte isn't 3301d0f0931dSRoss Zwisler * pte_none() under vmf->ptl protection when we return to 3302d0f0931dSRoss Zwisler * alloc_set_pte(). 3303d0f0931dSRoss Zwisler */ 330482b0f8c3SJan Kara vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, 330582b0f8c3SJan Kara &vmf->ptl); 33067267ec00SKirill A. Shutemov return 0; 33077267ec00SKirill A. Shutemov } 33087267ec00SKirill A. Shutemov 3309e496cf3dSKirill A. Shutemov #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE 331010102459SKirill A. Shutemov 331110102459SKirill A. Shutemov #define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1) 331210102459SKirill A. Shutemov static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, 331310102459SKirill A. Shutemov unsigned long haddr) 331410102459SKirill A. Shutemov { 331510102459SKirill A. Shutemov if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) != 331610102459SKirill A. Shutemov (vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK)) 331710102459SKirill A. Shutemov return false; 331810102459SKirill A. Shutemov if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) 331910102459SKirill A. Shutemov return false; 332010102459SKirill A. Shutemov return true; 332110102459SKirill A. Shutemov } 332210102459SKirill A. Shutemov 332382b0f8c3SJan Kara static void deposit_prealloc_pte(struct vm_fault *vmf) 3324953c66c2SAneesh Kumar K.V { 332582b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3326953c66c2SAneesh Kumar K.V 332782b0f8c3SJan Kara pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); 3328953c66c2SAneesh Kumar K.V /* 3329953c66c2SAneesh Kumar K.V * We are going to consume the prealloc table, 3330953c66c2SAneesh Kumar K.V * count that as nr_ptes. 3331953c66c2SAneesh Kumar K.V */ 3332c4812909SKirill A. Shutemov mm_inc_nr_ptes(vma->vm_mm); 33337f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 3334953c66c2SAneesh Kumar K.V } 3335953c66c2SAneesh Kumar K.V 333682b0f8c3SJan Kara static int do_set_pmd(struct vm_fault *vmf, struct page *page) 333710102459SKirill A. Shutemov { 333882b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 333982b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 334082b0f8c3SJan Kara unsigned long haddr = vmf->address & HPAGE_PMD_MASK; 334110102459SKirill A. Shutemov pmd_t entry; 334210102459SKirill A. Shutemov int i, ret; 334310102459SKirill A. Shutemov 334410102459SKirill A. Shutemov if (!transhuge_vma_suitable(vma, haddr)) 334510102459SKirill A. Shutemov return VM_FAULT_FALLBACK; 334610102459SKirill A. Shutemov 334710102459SKirill A. Shutemov ret = VM_FAULT_FALLBACK; 334810102459SKirill A. Shutemov page = compound_head(page); 334910102459SKirill A. Shutemov 3350953c66c2SAneesh Kumar K.V /* 3351953c66c2SAneesh Kumar K.V * Archs like ppc64 need additonal space to store information 3352953c66c2SAneesh Kumar K.V * related to pte entry. Use the preallocated table for that. 3353953c66c2SAneesh Kumar K.V */ 335482b0f8c3SJan Kara if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) { 335582b0f8c3SJan Kara vmf->prealloc_pte = pte_alloc_one(vma->vm_mm, vmf->address); 335682b0f8c3SJan Kara if (!vmf->prealloc_pte) 3357953c66c2SAneesh Kumar K.V return VM_FAULT_OOM; 3358953c66c2SAneesh Kumar K.V smp_wmb(); /* See comment in __pte_alloc() */ 3359953c66c2SAneesh Kumar K.V } 3360953c66c2SAneesh Kumar K.V 336182b0f8c3SJan Kara vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); 336282b0f8c3SJan Kara if (unlikely(!pmd_none(*vmf->pmd))) 336310102459SKirill A. Shutemov goto out; 336410102459SKirill A. Shutemov 336510102459SKirill A. Shutemov for (i = 0; i < HPAGE_PMD_NR; i++) 336610102459SKirill A. Shutemov flush_icache_page(vma, page + i); 336710102459SKirill A. Shutemov 336810102459SKirill A. Shutemov entry = mk_huge_pmd(page, vma->vm_page_prot); 336910102459SKirill A. Shutemov if (write) 3370f55e1014SLinus Torvalds entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); 337110102459SKirill A. Shutemov 337210102459SKirill A. Shutemov add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR); 337310102459SKirill A. Shutemov page_add_file_rmap(page, true); 3374953c66c2SAneesh Kumar K.V /* 3375953c66c2SAneesh Kumar K.V * deposit and withdraw with pmd lock held 3376953c66c2SAneesh Kumar K.V */ 3377953c66c2SAneesh Kumar K.V if (arch_needs_pgtable_deposit()) 337882b0f8c3SJan Kara deposit_prealloc_pte(vmf); 337910102459SKirill A. Shutemov 338082b0f8c3SJan Kara set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); 338110102459SKirill A. Shutemov 338282b0f8c3SJan Kara update_mmu_cache_pmd(vma, haddr, vmf->pmd); 338310102459SKirill A. Shutemov 338410102459SKirill A. Shutemov /* fault is handled */ 338510102459SKirill A. Shutemov ret = 0; 338695ecedcdSKirill A. Shutemov count_vm_event(THP_FILE_MAPPED); 338710102459SKirill A. Shutemov out: 338882b0f8c3SJan Kara spin_unlock(vmf->ptl); 338910102459SKirill A. Shutemov return ret; 339010102459SKirill A. Shutemov } 339110102459SKirill A. Shutemov #else 339282b0f8c3SJan Kara static int do_set_pmd(struct vm_fault *vmf, struct page *page) 339310102459SKirill A. Shutemov { 339410102459SKirill A. Shutemov BUILD_BUG(); 339510102459SKirill A. Shutemov return 0; 339610102459SKirill A. Shutemov } 339710102459SKirill A. Shutemov #endif 339810102459SKirill A. Shutemov 33998c6e50b0SKirill A. Shutemov /** 34007267ec00SKirill A. Shutemov * alloc_set_pte - setup new PTE entry for given page and add reverse page 34017267ec00SKirill A. Shutemov * mapping. If needed, the fucntion allocates page table or use pre-allocated. 34028c6e50b0SKirill A. Shutemov * 340382b0f8c3SJan Kara * @vmf: fault environment 34047267ec00SKirill A. Shutemov * @memcg: memcg to charge page (only for private mappings) 34058c6e50b0SKirill A. Shutemov * @page: page to map 34068c6e50b0SKirill A. Shutemov * 340782b0f8c3SJan Kara * Caller must take care of unlocking vmf->ptl, if vmf->pte is non-NULL on 340882b0f8c3SJan Kara * return. 34098c6e50b0SKirill A. Shutemov * 34108c6e50b0SKirill A. Shutemov * Target users are page handler itself and implementations of 34118c6e50b0SKirill A. Shutemov * vm_ops->map_pages. 34128c6e50b0SKirill A. Shutemov */ 341382b0f8c3SJan Kara int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, 34147267ec00SKirill A. Shutemov struct page *page) 34153bb97794SKirill A. Shutemov { 341682b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 341782b0f8c3SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 34183bb97794SKirill A. Shutemov pte_t entry; 341910102459SKirill A. Shutemov int ret; 342010102459SKirill A. Shutemov 342182b0f8c3SJan Kara if (pmd_none(*vmf->pmd) && PageTransCompound(page) && 3422e496cf3dSKirill A. Shutemov IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { 342310102459SKirill A. Shutemov /* THP on COW? */ 342410102459SKirill A. Shutemov VM_BUG_ON_PAGE(memcg, page); 342510102459SKirill A. Shutemov 342682b0f8c3SJan Kara ret = do_set_pmd(vmf, page); 342710102459SKirill A. Shutemov if (ret != VM_FAULT_FALLBACK) 3428b0b9b3dfSHugh Dickins return ret; 342910102459SKirill A. Shutemov } 34303bb97794SKirill A. Shutemov 343182b0f8c3SJan Kara if (!vmf->pte) { 343282b0f8c3SJan Kara ret = pte_alloc_one_map(vmf); 34337267ec00SKirill A. Shutemov if (ret) 3434b0b9b3dfSHugh Dickins return ret; 34357267ec00SKirill A. Shutemov } 34367267ec00SKirill A. Shutemov 34377267ec00SKirill A. Shutemov /* Re-check under ptl */ 3438b0b9b3dfSHugh Dickins if (unlikely(!pte_none(*vmf->pte))) 3439b0b9b3dfSHugh Dickins return VM_FAULT_NOPAGE; 34407267ec00SKirill A. Shutemov 34413bb97794SKirill A. Shutemov flush_icache_page(vma, page); 34423bb97794SKirill A. Shutemov entry = mk_pte(page, vma->vm_page_prot); 34433bb97794SKirill A. Shutemov if (write) 34443bb97794SKirill A. Shutemov entry = maybe_mkwrite(pte_mkdirty(entry), vma); 3445bae473a4SKirill A. Shutemov /* copy-on-write page */ 3446bae473a4SKirill A. Shutemov if (write && !(vma->vm_flags & VM_SHARED)) { 34473bb97794SKirill A. Shutemov inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); 344882b0f8c3SJan Kara page_add_new_anon_rmap(page, vma, vmf->address, false); 34497267ec00SKirill A. Shutemov mem_cgroup_commit_charge(page, memcg, false, false); 34507267ec00SKirill A. Shutemov lru_cache_add_active_or_unevictable(page, vma); 34513bb97794SKirill A. Shutemov } else { 3452eca56ff9SJerome Marchand inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); 3453dd78feddSKirill A. Shutemov page_add_file_rmap(page, false); 34543bb97794SKirill A. Shutemov } 345582b0f8c3SJan Kara set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); 34563bb97794SKirill A. Shutemov 34573bb97794SKirill A. Shutemov /* no need to invalidate: a not-present page won't be cached */ 345882b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 34597267ec00SKirill A. Shutemov 3460b0b9b3dfSHugh Dickins return 0; 34613bb97794SKirill A. Shutemov } 34623bb97794SKirill A. Shutemov 34639118c0cbSJan Kara 34649118c0cbSJan Kara /** 34659118c0cbSJan Kara * finish_fault - finish page fault once we have prepared the page to fault 34669118c0cbSJan Kara * 34679118c0cbSJan Kara * @vmf: structure describing the fault 34689118c0cbSJan Kara * 34699118c0cbSJan Kara * This function handles all that is needed to finish a page fault once the 34709118c0cbSJan Kara * page to fault in is prepared. It handles locking of PTEs, inserts PTE for 34719118c0cbSJan Kara * given page, adds reverse page mapping, handles memcg charges and LRU 34729118c0cbSJan Kara * addition. The function returns 0 on success, VM_FAULT_ code in case of 34739118c0cbSJan Kara * error. 34749118c0cbSJan Kara * 34759118c0cbSJan Kara * The function expects the page to be locked and on success it consumes a 34769118c0cbSJan Kara * reference of a page being mapped (for the PTE which maps it). 34779118c0cbSJan Kara */ 34789118c0cbSJan Kara int finish_fault(struct vm_fault *vmf) 34799118c0cbSJan Kara { 34809118c0cbSJan Kara struct page *page; 34816b31d595SMichal Hocko int ret = 0; 34829118c0cbSJan Kara 34839118c0cbSJan Kara /* Did we COW the page? */ 34849118c0cbSJan Kara if ((vmf->flags & FAULT_FLAG_WRITE) && 34859118c0cbSJan Kara !(vmf->vma->vm_flags & VM_SHARED)) 34869118c0cbSJan Kara page = vmf->cow_page; 34879118c0cbSJan Kara else 34889118c0cbSJan Kara page = vmf->page; 34896b31d595SMichal Hocko 34906b31d595SMichal Hocko /* 34916b31d595SMichal Hocko * check even for read faults because we might have lost our CoWed 34926b31d595SMichal Hocko * page 34936b31d595SMichal Hocko */ 34946b31d595SMichal Hocko if (!(vmf->vma->vm_flags & VM_SHARED)) 34956b31d595SMichal Hocko ret = check_stable_address_space(vmf->vma->vm_mm); 34966b31d595SMichal Hocko if (!ret) 34979118c0cbSJan Kara ret = alloc_set_pte(vmf, vmf->memcg, page); 34989118c0cbSJan Kara if (vmf->pte) 34999118c0cbSJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 35009118c0cbSJan Kara return ret; 35019118c0cbSJan Kara } 35029118c0cbSJan Kara 35033a91053aSKirill A. Shutemov static unsigned long fault_around_bytes __read_mostly = 35043a91053aSKirill A. Shutemov rounddown_pow_of_two(65536); 3505a9b0f861SKirill A. Shutemov 35061592eef0SKirill A. Shutemov #ifdef CONFIG_DEBUG_FS 3507a9b0f861SKirill A. Shutemov static int fault_around_bytes_get(void *data, u64 *val) 35081592eef0SKirill A. Shutemov { 3509a9b0f861SKirill A. Shutemov *val = fault_around_bytes; 35101592eef0SKirill A. Shutemov return 0; 35111592eef0SKirill A. Shutemov } 35121592eef0SKirill A. Shutemov 3513b4903d6eSAndrey Ryabinin /* 3514b4903d6eSAndrey Ryabinin * fault_around_pages() and fault_around_mask() expects fault_around_bytes 3515b4903d6eSAndrey Ryabinin * rounded down to nearest page order. It's what do_fault_around() expects to 3516b4903d6eSAndrey Ryabinin * see. 3517b4903d6eSAndrey Ryabinin */ 3518a9b0f861SKirill A. Shutemov static int fault_around_bytes_set(void *data, u64 val) 35191592eef0SKirill A. Shutemov { 3520a9b0f861SKirill A. Shutemov if (val / PAGE_SIZE > PTRS_PER_PTE) 35211592eef0SKirill A. Shutemov return -EINVAL; 3522b4903d6eSAndrey Ryabinin if (val > PAGE_SIZE) 3523b4903d6eSAndrey Ryabinin fault_around_bytes = rounddown_pow_of_two(val); 3524b4903d6eSAndrey Ryabinin else 3525b4903d6eSAndrey Ryabinin fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ 35261592eef0SKirill A. Shutemov return 0; 35271592eef0SKirill A. Shutemov } 35280a1345f8SYevgen Pronenko DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, 3529a9b0f861SKirill A. Shutemov fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); 35301592eef0SKirill A. Shutemov 35311592eef0SKirill A. Shutemov static int __init fault_around_debugfs(void) 35321592eef0SKirill A. Shutemov { 35331592eef0SKirill A. Shutemov void *ret; 35341592eef0SKirill A. Shutemov 35350a1345f8SYevgen Pronenko ret = debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, 3536a9b0f861SKirill A. Shutemov &fault_around_bytes_fops); 35371592eef0SKirill A. Shutemov if (!ret) 3538a9b0f861SKirill A. Shutemov pr_warn("Failed to create fault_around_bytes in debugfs"); 35391592eef0SKirill A. Shutemov return 0; 35401592eef0SKirill A. Shutemov } 35411592eef0SKirill A. Shutemov late_initcall(fault_around_debugfs); 35421592eef0SKirill A. Shutemov #endif 35438c6e50b0SKirill A. Shutemov 35441fdb412bSKirill A. Shutemov /* 35451fdb412bSKirill A. Shutemov * do_fault_around() tries to map few pages around the fault address. The hope 35461fdb412bSKirill A. Shutemov * is that the pages will be needed soon and this will lower the number of 35471fdb412bSKirill A. Shutemov * faults to handle. 35481fdb412bSKirill A. Shutemov * 35491fdb412bSKirill A. Shutemov * It uses vm_ops->map_pages() to map the pages, which skips the page if it's 35501fdb412bSKirill A. Shutemov * not ready to be mapped: not up-to-date, locked, etc. 35511fdb412bSKirill A. Shutemov * 35521fdb412bSKirill A. Shutemov * This function is called with the page table lock taken. In the split ptlock 35531fdb412bSKirill A. Shutemov * case the page table lock only protects only those entries which belong to 35541fdb412bSKirill A. Shutemov * the page table corresponding to the fault address. 35551fdb412bSKirill A. Shutemov * 35561fdb412bSKirill A. Shutemov * This function doesn't cross the VMA boundaries, in order to call map_pages() 35571fdb412bSKirill A. Shutemov * only once. 35581fdb412bSKirill A. Shutemov * 35591fdb412bSKirill A. Shutemov * fault_around_pages() defines how many pages we'll try to map. 35601fdb412bSKirill A. Shutemov * do_fault_around() expects it to return a power of two less than or equal to 35611fdb412bSKirill A. Shutemov * PTRS_PER_PTE. 35621fdb412bSKirill A. Shutemov * 35631fdb412bSKirill A. Shutemov * The virtual address of the area that we map is naturally aligned to the 35641fdb412bSKirill A. Shutemov * fault_around_pages() value (and therefore to page order). This way it's 35651fdb412bSKirill A. Shutemov * easier to guarantee that we don't cross page table boundaries. 35661fdb412bSKirill A. Shutemov */ 35670721ec8bSJan Kara static int do_fault_around(struct vm_fault *vmf) 35688c6e50b0SKirill A. Shutemov { 356982b0f8c3SJan Kara unsigned long address = vmf->address, nr_pages, mask; 35700721ec8bSJan Kara pgoff_t start_pgoff = vmf->pgoff; 3571bae473a4SKirill A. Shutemov pgoff_t end_pgoff; 35727267ec00SKirill A. Shutemov int off, ret = 0; 35738c6e50b0SKirill A. Shutemov 35744db0c3c2SJason Low nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; 3575aecd6f44SKirill A. Shutemov mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; 3576aecd6f44SKirill A. Shutemov 357782b0f8c3SJan Kara vmf->address = max(address & mask, vmf->vma->vm_start); 357882b0f8c3SJan Kara off = ((address - vmf->address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 3579bae473a4SKirill A. Shutemov start_pgoff -= off; 35808c6e50b0SKirill A. Shutemov 35818c6e50b0SKirill A. Shutemov /* 3582bae473a4SKirill A. Shutemov * end_pgoff is either end of page table or end of vma 3583bae473a4SKirill A. Shutemov * or fault_around_pages() from start_pgoff, depending what is nearest. 35848c6e50b0SKirill A. Shutemov */ 3585bae473a4SKirill A. Shutemov end_pgoff = start_pgoff - 358682b0f8c3SJan Kara ((vmf->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + 35878c6e50b0SKirill A. Shutemov PTRS_PER_PTE - 1; 358882b0f8c3SJan Kara end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1, 3589bae473a4SKirill A. Shutemov start_pgoff + nr_pages - 1); 35908c6e50b0SKirill A. Shutemov 359182b0f8c3SJan Kara if (pmd_none(*vmf->pmd)) { 359282b0f8c3SJan Kara vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm, 359382b0f8c3SJan Kara vmf->address); 359482b0f8c3SJan Kara if (!vmf->prealloc_pte) 3595c5f88bd2SVegard Nossum goto out; 35967267ec00SKirill A. Shutemov smp_wmb(); /* See comment in __pte_alloc() */ 35978c6e50b0SKirill A. Shutemov } 35988c6e50b0SKirill A. Shutemov 359982b0f8c3SJan Kara vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff); 36007267ec00SKirill A. Shutemov 36017267ec00SKirill A. Shutemov /* Huge page is mapped? Page fault is solved */ 360282b0f8c3SJan Kara if (pmd_trans_huge(*vmf->pmd)) { 36037267ec00SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 36047267ec00SKirill A. Shutemov goto out; 36058c6e50b0SKirill A. Shutemov } 36068c6e50b0SKirill A. Shutemov 36077267ec00SKirill A. Shutemov /* ->map_pages() haven't done anything useful. Cold page cache? */ 360882b0f8c3SJan Kara if (!vmf->pte) 36097267ec00SKirill A. Shutemov goto out; 36107267ec00SKirill A. Shutemov 36117267ec00SKirill A. Shutemov /* check if the page fault is solved */ 361282b0f8c3SJan Kara vmf->pte -= (vmf->address >> PAGE_SHIFT) - (address >> PAGE_SHIFT); 361382b0f8c3SJan Kara if (!pte_none(*vmf->pte)) 36147267ec00SKirill A. Shutemov ret = VM_FAULT_NOPAGE; 361582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 36167267ec00SKirill A. Shutemov out: 361782b0f8c3SJan Kara vmf->address = address; 361882b0f8c3SJan Kara vmf->pte = NULL; 36197267ec00SKirill A. Shutemov return ret; 36207267ec00SKirill A. Shutemov } 36217267ec00SKirill A. Shutemov 36220721ec8bSJan Kara static int do_read_fault(struct vm_fault *vmf) 3623e655fb29SKirill A. Shutemov { 362482b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 36258c6e50b0SKirill A. Shutemov int ret = 0; 36268c6e50b0SKirill A. Shutemov 36278c6e50b0SKirill A. Shutemov /* 36288c6e50b0SKirill A. Shutemov * Let's call ->map_pages() first and use ->fault() as fallback 36298c6e50b0SKirill A. Shutemov * if page by the offset is not ready to be mapped (cold cache or 36308c6e50b0SKirill A. Shutemov * something). 36318c6e50b0SKirill A. Shutemov */ 36329b4bdd2fSKirill A. Shutemov if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { 36330721ec8bSJan Kara ret = do_fault_around(vmf); 36347267ec00SKirill A. Shutemov if (ret) 36357267ec00SKirill A. Shutemov return ret; 36368c6e50b0SKirill A. Shutemov } 3637e655fb29SKirill A. Shutemov 3638936ca80dSJan Kara ret = __do_fault(vmf); 3639e655fb29SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3640e655fb29SKirill A. Shutemov return ret; 3641e655fb29SKirill A. Shutemov 36429118c0cbSJan Kara ret |= finish_fault(vmf); 3643936ca80dSJan Kara unlock_page(vmf->page); 36447267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3645936ca80dSJan Kara put_page(vmf->page); 3646e655fb29SKirill A. Shutemov return ret; 3647e655fb29SKirill A. Shutemov } 3648e655fb29SKirill A. Shutemov 36490721ec8bSJan Kara static int do_cow_fault(struct vm_fault *vmf) 3650ec47c3b9SKirill A. Shutemov { 365182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3652ec47c3b9SKirill A. Shutemov int ret; 3653ec47c3b9SKirill A. Shutemov 3654ec47c3b9SKirill A. Shutemov if (unlikely(anon_vma_prepare(vma))) 3655ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 3656ec47c3b9SKirill A. Shutemov 3657936ca80dSJan Kara vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); 3658936ca80dSJan Kara if (!vmf->cow_page) 3659ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 3660ec47c3b9SKirill A. Shutemov 3661936ca80dSJan Kara if (mem_cgroup_try_charge(vmf->cow_page, vma->vm_mm, GFP_KERNEL, 36623917048dSJan Kara &vmf->memcg, false)) { 3663936ca80dSJan Kara put_page(vmf->cow_page); 3664ec47c3b9SKirill A. Shutemov return VM_FAULT_OOM; 3665ec47c3b9SKirill A. Shutemov } 3666ec47c3b9SKirill A. Shutemov 3667936ca80dSJan Kara ret = __do_fault(vmf); 3668ec47c3b9SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3669ec47c3b9SKirill A. Shutemov goto uncharge_out; 36703917048dSJan Kara if (ret & VM_FAULT_DONE_COW) 36713917048dSJan Kara return ret; 3672ec47c3b9SKirill A. Shutemov 3673936ca80dSJan Kara copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma); 3674936ca80dSJan Kara __SetPageUptodate(vmf->cow_page); 3675ec47c3b9SKirill A. Shutemov 36769118c0cbSJan Kara ret |= finish_fault(vmf); 3677936ca80dSJan Kara unlock_page(vmf->page); 3678936ca80dSJan Kara put_page(vmf->page); 36797267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 36807267ec00SKirill A. Shutemov goto uncharge_out; 3681ec47c3b9SKirill A. Shutemov return ret; 3682ec47c3b9SKirill A. Shutemov uncharge_out: 36833917048dSJan Kara mem_cgroup_cancel_charge(vmf->cow_page, vmf->memcg, false); 3684936ca80dSJan Kara put_page(vmf->cow_page); 3685ec47c3b9SKirill A. Shutemov return ret; 3686ec47c3b9SKirill A. Shutemov } 3687ec47c3b9SKirill A. Shutemov 36880721ec8bSJan Kara static int do_shared_fault(struct vm_fault *vmf) 36891da177e4SLinus Torvalds { 369082b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3691f0c6d4d2SKirill A. Shutemov int ret, tmp; 36921d65f86dSKAMEZAWA Hiroyuki 3693936ca80dSJan Kara ret = __do_fault(vmf); 36947eae74afSKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) 3695f0c6d4d2SKirill A. Shutemov return ret; 36961da177e4SLinus Torvalds 36971da177e4SLinus Torvalds /* 3698f0c6d4d2SKirill A. Shutemov * Check if the backing address space wants to know that the page is 3699f0c6d4d2SKirill A. Shutemov * about to become writable 37001da177e4SLinus Torvalds */ 3701fb09a464SKirill A. Shutemov if (vma->vm_ops->page_mkwrite) { 3702936ca80dSJan Kara unlock_page(vmf->page); 370338b8cb7fSJan Kara tmp = do_page_mkwrite(vmf); 3704fb09a464SKirill A. Shutemov if (unlikely(!tmp || 3705fb09a464SKirill A. Shutemov (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { 3706936ca80dSJan Kara put_page(vmf->page); 3707f0c6d4d2SKirill A. Shutemov return tmp; 370869676147SMark Fasheh } 3709d0217ac0SNick Piggin } 3710fb09a464SKirill A. Shutemov 37119118c0cbSJan Kara ret |= finish_fault(vmf); 37127267ec00SKirill A. Shutemov if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 37137267ec00SKirill A. Shutemov VM_FAULT_RETRY))) { 3714936ca80dSJan Kara unlock_page(vmf->page); 3715936ca80dSJan Kara put_page(vmf->page); 3716f0c6d4d2SKirill A. Shutemov return ret; 37179637a5efSDavid Howells } 3718d00806b1SNick Piggin 371997ba0c2bSJan Kara fault_dirty_shared_page(vma, vmf->page); 3720b827e496SNick Piggin return ret; 372154cb8821SNick Piggin } 3722d00806b1SNick Piggin 37239a95f3cfSPaul Cassella /* 37249a95f3cfSPaul Cassella * We enter with non-exclusive mmap_sem (to exclude vma changes, 37259a95f3cfSPaul Cassella * but allow concurrent faults). 37269a95f3cfSPaul Cassella * The mmap_sem may have been released depending on flags and our 37279a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 37289a95f3cfSPaul Cassella */ 372982b0f8c3SJan Kara static int do_fault(struct vm_fault *vmf) 373054cb8821SNick Piggin { 373182b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 3732b0b9b3dfSHugh Dickins int ret; 373354cb8821SNick Piggin 37346b7339f4SKirill A. Shutemov /* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */ 37356b7339f4SKirill A. Shutemov if (!vma->vm_ops->fault) 3736b0b9b3dfSHugh Dickins ret = VM_FAULT_SIGBUS; 3737b0b9b3dfSHugh Dickins else if (!(vmf->flags & FAULT_FLAG_WRITE)) 3738b0b9b3dfSHugh Dickins ret = do_read_fault(vmf); 3739b0b9b3dfSHugh Dickins else if (!(vma->vm_flags & VM_SHARED)) 3740b0b9b3dfSHugh Dickins ret = do_cow_fault(vmf); 3741b0b9b3dfSHugh Dickins else 3742b0b9b3dfSHugh Dickins ret = do_shared_fault(vmf); 3743b0b9b3dfSHugh Dickins 3744b0b9b3dfSHugh Dickins /* preallocated pagetable is unused: free it */ 3745b0b9b3dfSHugh Dickins if (vmf->prealloc_pte) { 3746b0b9b3dfSHugh Dickins pte_free(vma->vm_mm, vmf->prealloc_pte); 37477f2b6ce8STobin C Harding vmf->prealloc_pte = NULL; 3748b0b9b3dfSHugh Dickins } 3749b0b9b3dfSHugh Dickins return ret; 375054cb8821SNick Piggin } 375154cb8821SNick Piggin 3752b19a9939SRashika Kheria static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 375304bb2f94SRik van Riel unsigned long addr, int page_nid, 375404bb2f94SRik van Riel int *flags) 37559532fec1SMel Gorman { 37569532fec1SMel Gorman get_page(page); 37579532fec1SMel Gorman 37589532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 375904bb2f94SRik van Riel if (page_nid == numa_node_id()) { 37609532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 376104bb2f94SRik van Riel *flags |= TNF_FAULT_LOCAL; 376204bb2f94SRik van Riel } 37639532fec1SMel Gorman 37649532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 37659532fec1SMel Gorman } 37669532fec1SMel Gorman 37672994302bSJan Kara static int do_numa_page(struct vm_fault *vmf) 3768d10e63f2SMel Gorman { 376982b0f8c3SJan Kara struct vm_area_struct *vma = vmf->vma; 37704daae3b4SMel Gorman struct page *page = NULL; 37718191acbdSMel Gorman int page_nid = -1; 377290572890SPeter Zijlstra int last_cpupid; 3773cbee9f88SPeter Zijlstra int target_nid; 3774b8593bfdSMel Gorman bool migrated = false; 3775cee216a6SAneesh Kumar K.V pte_t pte; 3776288bc549SAneesh Kumar K.V bool was_writable = pte_savedwrite(vmf->orig_pte); 37776688cc05SPeter Zijlstra int flags = 0; 3778d10e63f2SMel Gorman 3779d10e63f2SMel Gorman /* 3780d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 3781d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 3782d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 3783d10e63f2SMel Gorman */ 378482b0f8c3SJan Kara vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); 378582b0f8c3SJan Kara spin_lock(vmf->ptl); 3786cee216a6SAneesh Kumar K.V if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { 378782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 37884daae3b4SMel Gorman goto out; 37894daae3b4SMel Gorman } 37904daae3b4SMel Gorman 3791cee216a6SAneesh Kumar K.V /* 3792cee216a6SAneesh Kumar K.V * Make it present again, Depending on how arch implementes non 3793cee216a6SAneesh Kumar K.V * accessible ptes, some can allow access by kernel mode. 3794cee216a6SAneesh Kumar K.V */ 3795cee216a6SAneesh Kumar K.V pte = ptep_modify_prot_start(vma->vm_mm, vmf->address, vmf->pte); 37964d942466SMel Gorman pte = pte_modify(pte, vma->vm_page_prot); 37974d942466SMel Gorman pte = pte_mkyoung(pte); 3798b191f9b1SMel Gorman if (was_writable) 3799b191f9b1SMel Gorman pte = pte_mkwrite(pte); 3800cee216a6SAneesh Kumar K.V ptep_modify_prot_commit(vma->vm_mm, vmf->address, vmf->pte, pte); 380182b0f8c3SJan Kara update_mmu_cache(vma, vmf->address, vmf->pte); 3802d10e63f2SMel Gorman 380382b0f8c3SJan Kara page = vm_normal_page(vma, vmf->address, pte); 3804d10e63f2SMel Gorman if (!page) { 380582b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3806d10e63f2SMel Gorman return 0; 3807d10e63f2SMel Gorman } 3808d10e63f2SMel Gorman 3809e81c4802SKirill A. Shutemov /* TODO: handle PTE-mapped THP */ 3810e81c4802SKirill A. Shutemov if (PageCompound(page)) { 381182b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 3812e81c4802SKirill A. Shutemov return 0; 3813e81c4802SKirill A. Shutemov } 3814e81c4802SKirill A. Shutemov 38156688cc05SPeter Zijlstra /* 3816bea66fbdSMel Gorman * Avoid grouping on RO pages in general. RO pages shouldn't hurt as 3817bea66fbdSMel Gorman * much anyway since they can be in shared cache state. This misses 3818bea66fbdSMel Gorman * the case where a mapping is writable but the process never writes 3819bea66fbdSMel Gorman * to it but pte_write gets cleared during protection updates and 3820bea66fbdSMel Gorman * pte_dirty has unpredictable behaviour between PTE scan updates, 3821bea66fbdSMel Gorman * background writeback, dirty balancing and application behaviour. 38226688cc05SPeter Zijlstra */ 3823d59dc7bcSRik van Riel if (!pte_write(pte)) 38246688cc05SPeter Zijlstra flags |= TNF_NO_GROUP; 38256688cc05SPeter Zijlstra 3826dabe1d99SRik van Riel /* 3827dabe1d99SRik van Riel * Flag if the page is shared between multiple address spaces. This 3828dabe1d99SRik van Riel * is later used when determining whether to group tasks together 3829dabe1d99SRik van Riel */ 3830dabe1d99SRik van Riel if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) 3831dabe1d99SRik van Riel flags |= TNF_SHARED; 3832dabe1d99SRik van Riel 383390572890SPeter Zijlstra last_cpupid = page_cpupid_last(page); 38348191acbdSMel Gorman page_nid = page_to_nid(page); 383582b0f8c3SJan Kara target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, 3836bae473a4SKirill A. Shutemov &flags); 383782b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 38384daae3b4SMel Gorman if (target_nid == -1) { 38394daae3b4SMel Gorman put_page(page); 38404daae3b4SMel Gorman goto out; 38414daae3b4SMel Gorman } 38424daae3b4SMel Gorman 38434daae3b4SMel Gorman /* Migrate to the requested node */ 38441bc115d8SMel Gorman migrated = migrate_misplaced_page(page, vma, target_nid); 38456688cc05SPeter Zijlstra if (migrated) { 38468191acbdSMel Gorman page_nid = target_nid; 38476688cc05SPeter Zijlstra flags |= TNF_MIGRATED; 3848074c2381SMel Gorman } else 3849074c2381SMel Gorman flags |= TNF_MIGRATE_FAIL; 38504daae3b4SMel Gorman 38514daae3b4SMel Gorman out: 38528191acbdSMel Gorman if (page_nid != -1) 38536688cc05SPeter Zijlstra task_numa_fault(last_cpupid, page_nid, 1, flags); 3854d10e63f2SMel Gorman return 0; 3855d10e63f2SMel Gorman } 3856d10e63f2SMel Gorman 385791a90140SGeert Uytterhoeven static inline int create_huge_pmd(struct vm_fault *vmf) 3858b96375f7SMatthew Wilcox { 3859f4200391SDave Jiang if (vma_is_anonymous(vmf->vma)) 386082b0f8c3SJan Kara return do_huge_pmd_anonymous_page(vmf); 3861a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 3862c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 3863b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 3864b96375f7SMatthew Wilcox } 3865b96375f7SMatthew Wilcox 3866183f24aaSGeert Uytterhoeven /* `inline' is required to avoid gcc 4.1.2 build error */ 3867183f24aaSGeert Uytterhoeven static inline int wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd) 3868b96375f7SMatthew Wilcox { 386982b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 387082b0f8c3SJan Kara return do_huge_pmd_wp_page(vmf, orig_pmd); 3871a2d58167SDave Jiang if (vmf->vma->vm_ops->huge_fault) 3872c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); 3873af9e4d5fSKirill A. Shutemov 3874af9e4d5fSKirill A. Shutemov /* COW handled on pte level: split pmd */ 387582b0f8c3SJan Kara VM_BUG_ON_VMA(vmf->vma->vm_flags & VM_SHARED, vmf->vma); 387682b0f8c3SJan Kara __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); 3877af9e4d5fSKirill A. Shutemov 3878b96375f7SMatthew Wilcox return VM_FAULT_FALLBACK; 3879b96375f7SMatthew Wilcox } 3880b96375f7SMatthew Wilcox 388138e08854SLorenzo Stoakes static inline bool vma_is_accessible(struct vm_area_struct *vma) 388238e08854SLorenzo Stoakes { 388338e08854SLorenzo Stoakes return vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE); 388438e08854SLorenzo Stoakes } 388538e08854SLorenzo Stoakes 3886a00cc7d9SMatthew Wilcox static int create_huge_pud(struct vm_fault *vmf) 3887a00cc7d9SMatthew Wilcox { 3888a00cc7d9SMatthew Wilcox #ifdef CONFIG_TRANSPARENT_HUGEPAGE 3889a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 3890a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 3891a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 3892a00cc7d9SMatthew Wilcox if (vmf->vma->vm_ops->huge_fault) 3893c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 3894a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 3895a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 3896a00cc7d9SMatthew Wilcox } 3897a00cc7d9SMatthew Wilcox 3898a00cc7d9SMatthew Wilcox static int wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) 3899a00cc7d9SMatthew Wilcox { 3900a00cc7d9SMatthew Wilcox #ifdef CONFIG_TRANSPARENT_HUGEPAGE 3901a00cc7d9SMatthew Wilcox /* No support for anonymous transparent PUD pages yet */ 3902a00cc7d9SMatthew Wilcox if (vma_is_anonymous(vmf->vma)) 3903a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 3904a00cc7d9SMatthew Wilcox if (vmf->vma->vm_ops->huge_fault) 3905c791ace1SDave Jiang return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); 3906a00cc7d9SMatthew Wilcox #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 3907a00cc7d9SMatthew Wilcox return VM_FAULT_FALLBACK; 3908a00cc7d9SMatthew Wilcox } 3909a00cc7d9SMatthew Wilcox 39101da177e4SLinus Torvalds /* 39111da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 39121da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 39131da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 39141da177e4SLinus Torvalds * 39151da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 39161da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 39171da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 39181da177e4SLinus Torvalds * 39197267ec00SKirill A. Shutemov * We enter with non-exclusive mmap_sem (to exclude vma changes, but allow 39207267ec00SKirill A. Shutemov * concurrent faults). 39219a95f3cfSPaul Cassella * 39227267ec00SKirill A. Shutemov * The mmap_sem may have been released depending on flags and our return value. 39237267ec00SKirill A. Shutemov * See filemap_fault() and __lock_page_or_retry(). 39241da177e4SLinus Torvalds */ 392582b0f8c3SJan Kara static int handle_pte_fault(struct vm_fault *vmf) 39261da177e4SLinus Torvalds { 39271da177e4SLinus Torvalds pte_t entry; 39281da177e4SLinus Torvalds 392982b0f8c3SJan Kara if (unlikely(pmd_none(*vmf->pmd))) { 39307267ec00SKirill A. Shutemov /* 39317267ec00SKirill A. Shutemov * Leave __pte_alloc() until later: because vm_ops->fault may 39327267ec00SKirill A. Shutemov * want to allocate huge page, and if we expose page table 39337267ec00SKirill A. Shutemov * for an instant, it will be difficult to retract from 39347267ec00SKirill A. Shutemov * concurrent faults and from rmap lookups. 39357267ec00SKirill A. Shutemov */ 393682b0f8c3SJan Kara vmf->pte = NULL; 39377267ec00SKirill A. Shutemov } else { 39387267ec00SKirill A. Shutemov /* See comment in pte_alloc_one_map() */ 3939d0f0931dSRoss Zwisler if (pmd_devmap_trans_unstable(vmf->pmd)) 39407267ec00SKirill A. Shutemov return 0; 39417267ec00SKirill A. Shutemov /* 39427267ec00SKirill A. Shutemov * A regular pmd is established and it can't morph into a huge 39437267ec00SKirill A. Shutemov * pmd from under us anymore at this point because we hold the 39447267ec00SKirill A. Shutemov * mmap_sem read mode and khugepaged takes it in write mode. 39457267ec00SKirill A. Shutemov * So now it's safe to run pte_offset_map(). 39467267ec00SKirill A. Shutemov */ 394782b0f8c3SJan Kara vmf->pte = pte_offset_map(vmf->pmd, vmf->address); 39482994302bSJan Kara vmf->orig_pte = *vmf->pte; 39497267ec00SKirill A. Shutemov 3950e37c6982SChristian Borntraeger /* 3951e37c6982SChristian Borntraeger * some architectures can have larger ptes than wordsize, 39527267ec00SKirill A. Shutemov * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and 3953b03a0fe0SPaul E. McKenney * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic 3954b03a0fe0SPaul E. McKenney * accesses. The code below just needs a consistent view 3955b03a0fe0SPaul E. McKenney * for the ifs and we later double check anyway with the 39567267ec00SKirill A. Shutemov * ptl lock held. So here a barrier will do. 3957e37c6982SChristian Borntraeger */ 3958e37c6982SChristian Borntraeger barrier(); 39592994302bSJan Kara if (pte_none(vmf->orig_pte)) { 396082b0f8c3SJan Kara pte_unmap(vmf->pte); 396182b0f8c3SJan Kara vmf->pte = NULL; 39627267ec00SKirill A. Shutemov } 39637267ec00SKirill A. Shutemov } 39647267ec00SKirill A. Shutemov 396582b0f8c3SJan Kara if (!vmf->pte) { 396682b0f8c3SJan Kara if (vma_is_anonymous(vmf->vma)) 396782b0f8c3SJan Kara return do_anonymous_page(vmf); 3968b5330628SOleg Nesterov else 396982b0f8c3SJan Kara return do_fault(vmf); 397065500d23SHugh Dickins } 39717267ec00SKirill A. Shutemov 39722994302bSJan Kara if (!pte_present(vmf->orig_pte)) 39732994302bSJan Kara return do_swap_page(vmf); 39741da177e4SLinus Torvalds 39752994302bSJan Kara if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) 39762994302bSJan Kara return do_numa_page(vmf); 3977d10e63f2SMel Gorman 397882b0f8c3SJan Kara vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); 397982b0f8c3SJan Kara spin_lock(vmf->ptl); 39802994302bSJan Kara entry = vmf->orig_pte; 398182b0f8c3SJan Kara if (unlikely(!pte_same(*vmf->pte, entry))) 39828f4e2101SHugh Dickins goto unlock; 398382b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) { 3984f6f37321SLinus Torvalds if (!pte_write(entry)) 39852994302bSJan Kara return do_wp_page(vmf); 39861da177e4SLinus Torvalds entry = pte_mkdirty(entry); 39871da177e4SLinus Torvalds } 39881da177e4SLinus Torvalds entry = pte_mkyoung(entry); 398982b0f8c3SJan Kara if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, 399082b0f8c3SJan Kara vmf->flags & FAULT_FLAG_WRITE)) { 399182b0f8c3SJan Kara update_mmu_cache(vmf->vma, vmf->address, vmf->pte); 39921a44e149SAndrea Arcangeli } else { 39931a44e149SAndrea Arcangeli /* 39941a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 39951a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 39961a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 39971a44e149SAndrea Arcangeli * with threads. 39981a44e149SAndrea Arcangeli */ 399982b0f8c3SJan Kara if (vmf->flags & FAULT_FLAG_WRITE) 400082b0f8c3SJan Kara flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); 40011a44e149SAndrea Arcangeli } 40028f4e2101SHugh Dickins unlock: 400382b0f8c3SJan Kara pte_unmap_unlock(vmf->pte, vmf->ptl); 400483c54070SNick Piggin return 0; 40051da177e4SLinus Torvalds } 40061da177e4SLinus Torvalds 40071da177e4SLinus Torvalds /* 40081da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 40099a95f3cfSPaul Cassella * 40109a95f3cfSPaul Cassella * The mmap_sem may have been released depending on flags and our 40119a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 40121da177e4SLinus Torvalds */ 4013dcddffd4SKirill A. Shutemov static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 4014dcddffd4SKirill A. Shutemov unsigned int flags) 40151da177e4SLinus Torvalds { 401682b0f8c3SJan Kara struct vm_fault vmf = { 4017bae473a4SKirill A. Shutemov .vma = vma, 40181a29d85eSJan Kara .address = address & PAGE_MASK, 4019bae473a4SKirill A. Shutemov .flags = flags, 40200721ec8bSJan Kara .pgoff = linear_page_index(vma, address), 4021667240e0SJan Kara .gfp_mask = __get_fault_gfp_mask(vma), 4022bae473a4SKirill A. Shutemov }; 4023fde26bedSAnshuman Khandual unsigned int dirty = flags & FAULT_FLAG_WRITE; 4024dcddffd4SKirill A. Shutemov struct mm_struct *mm = vma->vm_mm; 40251da177e4SLinus Torvalds pgd_t *pgd; 4026c2febafcSKirill A. Shutemov p4d_t *p4d; 4027a2d58167SDave Jiang int ret; 40281da177e4SLinus Torvalds 40291da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 4030c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 4031c2febafcSKirill A. Shutemov if (!p4d) 4032c2febafcSKirill A. Shutemov return VM_FAULT_OOM; 4033a00cc7d9SMatthew Wilcox 4034c2febafcSKirill A. Shutemov vmf.pud = pud_alloc(mm, p4d, address); 4035a00cc7d9SMatthew Wilcox if (!vmf.pud) 4036c74df32cSHugh Dickins return VM_FAULT_OOM; 4037a00cc7d9SMatthew Wilcox if (pud_none(*vmf.pud) && transparent_hugepage_enabled(vma)) { 4038a00cc7d9SMatthew Wilcox ret = create_huge_pud(&vmf); 4039a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4040a00cc7d9SMatthew Wilcox return ret; 4041a00cc7d9SMatthew Wilcox } else { 4042a00cc7d9SMatthew Wilcox pud_t orig_pud = *vmf.pud; 4043a00cc7d9SMatthew Wilcox 4044a00cc7d9SMatthew Wilcox barrier(); 4045a00cc7d9SMatthew Wilcox if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) { 4046a00cc7d9SMatthew Wilcox 4047a00cc7d9SMatthew Wilcox /* NUMA case for anonymous PUDs would go here */ 4048a00cc7d9SMatthew Wilcox 4049f6f37321SLinus Torvalds if (dirty && !pud_write(orig_pud)) { 4050a00cc7d9SMatthew Wilcox ret = wp_huge_pud(&vmf, orig_pud); 4051a00cc7d9SMatthew Wilcox if (!(ret & VM_FAULT_FALLBACK)) 4052a00cc7d9SMatthew Wilcox return ret; 4053a00cc7d9SMatthew Wilcox } else { 4054a00cc7d9SMatthew Wilcox huge_pud_set_accessed(&vmf, orig_pud); 4055a00cc7d9SMatthew Wilcox return 0; 4056a00cc7d9SMatthew Wilcox } 4057a00cc7d9SMatthew Wilcox } 4058a00cc7d9SMatthew Wilcox } 4059a00cc7d9SMatthew Wilcox 4060a00cc7d9SMatthew Wilcox vmf.pmd = pmd_alloc(mm, vmf.pud, address); 406182b0f8c3SJan Kara if (!vmf.pmd) 4062c74df32cSHugh Dickins return VM_FAULT_OOM; 406382b0f8c3SJan Kara if (pmd_none(*vmf.pmd) && transparent_hugepage_enabled(vma)) { 4064a2d58167SDave Jiang ret = create_huge_pmd(&vmf); 4065c0292554SKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 4066c0292554SKirill A. Shutemov return ret; 406771e3aac0SAndrea Arcangeli } else { 406882b0f8c3SJan Kara pmd_t orig_pmd = *vmf.pmd; 40691f1d06c3SDavid Rientjes 407071e3aac0SAndrea Arcangeli barrier(); 407184c3fc4eSZi Yan if (unlikely(is_swap_pmd(orig_pmd))) { 407284c3fc4eSZi Yan VM_BUG_ON(thp_migration_supported() && 407384c3fc4eSZi Yan !is_pmd_migration_entry(orig_pmd)); 407484c3fc4eSZi Yan if (is_pmd_migration_entry(orig_pmd)) 407584c3fc4eSZi Yan pmd_migration_entry_wait(mm, vmf.pmd); 407684c3fc4eSZi Yan return 0; 407784c3fc4eSZi Yan } 40785c7fb56eSDan Williams if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) { 407938e08854SLorenzo Stoakes if (pmd_protnone(orig_pmd) && vma_is_accessible(vma)) 408082b0f8c3SJan Kara return do_huge_pmd_numa_page(&vmf, orig_pmd); 4081d10e63f2SMel Gorman 4082f6f37321SLinus Torvalds if (dirty && !pmd_write(orig_pmd)) { 408382b0f8c3SJan Kara ret = wp_huge_pmd(&vmf, orig_pmd); 40849845cbbdSKirill A. Shutemov if (!(ret & VM_FAULT_FALLBACK)) 40851f1d06c3SDavid Rientjes return ret; 4086a1dd450bSWill Deacon } else { 408782b0f8c3SJan Kara huge_pmd_set_accessed(&vmf, orig_pmd); 408871e3aac0SAndrea Arcangeli return 0; 408971e3aac0SAndrea Arcangeli } 409071e3aac0SAndrea Arcangeli } 40919845cbbdSKirill A. Shutemov } 409271e3aac0SAndrea Arcangeli 409382b0f8c3SJan Kara return handle_pte_fault(&vmf); 40941da177e4SLinus Torvalds } 40951da177e4SLinus Torvalds 40969a95f3cfSPaul Cassella /* 40979a95f3cfSPaul Cassella * By the time we get here, we already hold the mm semaphore 40989a95f3cfSPaul Cassella * 40999a95f3cfSPaul Cassella * The mmap_sem may have been released depending on flags and our 41009a95f3cfSPaul Cassella * return value. See filemap_fault() and __lock_page_or_retry(). 41019a95f3cfSPaul Cassella */ 4102dcddffd4SKirill A. Shutemov int handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 4103dcddffd4SKirill A. Shutemov unsigned int flags) 4104519e5247SJohannes Weiner { 4105519e5247SJohannes Weiner int ret; 4106519e5247SJohannes Weiner 4107519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 4108519e5247SJohannes Weiner 4109519e5247SJohannes Weiner count_vm_event(PGFAULT); 41102262185cSRoman Gushchin count_memcg_event_mm(vma->vm_mm, PGFAULT); 4111519e5247SJohannes Weiner 4112519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 4113519e5247SJohannes Weiner check_sync_rss_stat(current); 4114519e5247SJohannes Weiner 4115de0c799bSLaurent Dufour if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, 4116de0c799bSLaurent Dufour flags & FAULT_FLAG_INSTRUCTION, 4117de0c799bSLaurent Dufour flags & FAULT_FLAG_REMOTE)) 4118de0c799bSLaurent Dufour return VM_FAULT_SIGSEGV; 4119de0c799bSLaurent Dufour 4120519e5247SJohannes Weiner /* 4121519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 4122519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 4123519e5247SJohannes Weiner */ 4124519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 412549426420SJohannes Weiner mem_cgroup_oom_enable(); 4126519e5247SJohannes Weiner 4127bae473a4SKirill A. Shutemov if (unlikely(is_vm_hugetlb_page(vma))) 4128bae473a4SKirill A. Shutemov ret = hugetlb_fault(vma->vm_mm, vma, address, flags); 4129bae473a4SKirill A. Shutemov else 4130dcddffd4SKirill A. Shutemov ret = __handle_mm_fault(vma, address, flags); 4131519e5247SJohannes Weiner 413249426420SJohannes Weiner if (flags & FAULT_FLAG_USER) { 413349426420SJohannes Weiner mem_cgroup_oom_disable(); 413449426420SJohannes Weiner /* 413549426420SJohannes Weiner * The task may have entered a memcg OOM situation but 413649426420SJohannes Weiner * if the allocation error was handled gracefully (no 413749426420SJohannes Weiner * VM_FAULT_OOM), there is no need to kill anything. 413849426420SJohannes Weiner * Just clean up the OOM state peacefully. 413949426420SJohannes Weiner */ 414049426420SJohannes Weiner if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) 414149426420SJohannes Weiner mem_cgroup_oom_synchronize(false); 414249426420SJohannes Weiner } 41433812c8c8SJohannes Weiner 4144519e5247SJohannes Weiner return ret; 4145519e5247SJohannes Weiner } 4146e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(handle_mm_fault); 4147519e5247SJohannes Weiner 414890eceff1SKirill A. Shutemov #ifndef __PAGETABLE_P4D_FOLDED 414990eceff1SKirill A. Shutemov /* 415090eceff1SKirill A. Shutemov * Allocate p4d page table. 415190eceff1SKirill A. Shutemov * We've already handled the fast-path in-line. 415290eceff1SKirill A. Shutemov */ 415390eceff1SKirill A. Shutemov int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 415490eceff1SKirill A. Shutemov { 415590eceff1SKirill A. Shutemov p4d_t *new = p4d_alloc_one(mm, address); 415690eceff1SKirill A. Shutemov if (!new) 415790eceff1SKirill A. Shutemov return -ENOMEM; 415890eceff1SKirill A. Shutemov 415990eceff1SKirill A. Shutemov smp_wmb(); /* See comment in __pte_alloc */ 416090eceff1SKirill A. Shutemov 416190eceff1SKirill A. Shutemov spin_lock(&mm->page_table_lock); 416290eceff1SKirill A. Shutemov if (pgd_present(*pgd)) /* Another has populated it */ 416390eceff1SKirill A. Shutemov p4d_free(mm, new); 416490eceff1SKirill A. Shutemov else 416590eceff1SKirill A. Shutemov pgd_populate(mm, pgd, new); 416690eceff1SKirill A. Shutemov spin_unlock(&mm->page_table_lock); 416790eceff1SKirill A. Shutemov return 0; 416890eceff1SKirill A. Shutemov } 416990eceff1SKirill A. Shutemov #endif /* __PAGETABLE_P4D_FOLDED */ 417090eceff1SKirill A. Shutemov 41711da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 41721da177e4SLinus Torvalds /* 41731da177e4SLinus Torvalds * Allocate page upper directory. 4174872fec16SHugh Dickins * We've already handled the fast-path in-line. 41751da177e4SLinus Torvalds */ 4176c2febafcSKirill A. Shutemov int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) 41771da177e4SLinus Torvalds { 4178c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 4179c74df32cSHugh Dickins if (!new) 41801bb3630eSHugh Dickins return -ENOMEM; 41811da177e4SLinus Torvalds 4182362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 4183362a61adSNick Piggin 4184872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 4185c2febafcSKirill A. Shutemov #ifndef __ARCH_HAS_5LEVEL_HACK 4186b4e98d9aSKirill A. Shutemov if (!p4d_present(*p4d)) { 4187b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 4188c2febafcSKirill A. Shutemov p4d_populate(mm, p4d, new); 4189b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 4190c2febafcSKirill A. Shutemov pud_free(mm, new); 4191b4e98d9aSKirill A. Shutemov #else 4192b4e98d9aSKirill A. Shutemov if (!pgd_present(*p4d)) { 4193b4e98d9aSKirill A. Shutemov mm_inc_nr_puds(mm); 4194c2febafcSKirill A. Shutemov pgd_populate(mm, p4d, new); 4195b4e98d9aSKirill A. Shutemov } else /* Another has populated it */ 4196b4e98d9aSKirill A. Shutemov pud_free(mm, new); 4197c2febafcSKirill A. Shutemov #endif /* __ARCH_HAS_5LEVEL_HACK */ 4198872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 41991bb3630eSHugh Dickins return 0; 42001da177e4SLinus Torvalds } 42011da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 42021da177e4SLinus Torvalds 42031da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 42041da177e4SLinus Torvalds /* 42051da177e4SLinus Torvalds * Allocate page middle directory. 4206872fec16SHugh Dickins * We've already handled the fast-path in-line. 42071da177e4SLinus Torvalds */ 42081bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 42091da177e4SLinus Torvalds { 4210a00cc7d9SMatthew Wilcox spinlock_t *ptl; 4211c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 4212c74df32cSHugh Dickins if (!new) 42131bb3630eSHugh Dickins return -ENOMEM; 42141da177e4SLinus Torvalds 4215362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 4216362a61adSNick Piggin 4217a00cc7d9SMatthew Wilcox ptl = pud_lock(mm, pud); 42181da177e4SLinus Torvalds #ifndef __ARCH_HAS_4LEVEL_HACK 4219dc6c9a35SKirill A. Shutemov if (!pud_present(*pud)) { 4220dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 42211da177e4SLinus Torvalds pud_populate(mm, pud, new); 4222dc6c9a35SKirill A. Shutemov } else /* Another has populated it */ 42235e541973SBenjamin Herrenschmidt pmd_free(mm, new); 4224dc6c9a35SKirill A. Shutemov #else 4225dc6c9a35SKirill A. Shutemov if (!pgd_present(*pud)) { 4226dc6c9a35SKirill A. Shutemov mm_inc_nr_pmds(mm); 42271da177e4SLinus Torvalds pgd_populate(mm, pud, new); 4228dc6c9a35SKirill A. Shutemov } else /* Another has populated it */ 4229dc6c9a35SKirill A. Shutemov pmd_free(mm, new); 42301da177e4SLinus Torvalds #endif /* __ARCH_HAS_4LEVEL_HACK */ 4231a00cc7d9SMatthew Wilcox spin_unlock(ptl); 42321bb3630eSHugh Dickins return 0; 42331da177e4SLinus Torvalds } 42341da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 42351da177e4SLinus Torvalds 423609796395SRoss Zwisler static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address, 4237a4d1a885SJérôme Glisse unsigned long *start, unsigned long *end, 423809796395SRoss Zwisler pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp) 4239f8ad0f49SJohannes Weiner { 4240f8ad0f49SJohannes Weiner pgd_t *pgd; 4241c2febafcSKirill A. Shutemov p4d_t *p4d; 4242f8ad0f49SJohannes Weiner pud_t *pud; 4243f8ad0f49SJohannes Weiner pmd_t *pmd; 4244f8ad0f49SJohannes Weiner pte_t *ptep; 4245f8ad0f49SJohannes Weiner 4246f8ad0f49SJohannes Weiner pgd = pgd_offset(mm, address); 4247f8ad0f49SJohannes Weiner if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 4248f8ad0f49SJohannes Weiner goto out; 4249f8ad0f49SJohannes Weiner 4250c2febafcSKirill A. Shutemov p4d = p4d_offset(pgd, address); 4251c2febafcSKirill A. Shutemov if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) 4252c2febafcSKirill A. Shutemov goto out; 4253c2febafcSKirill A. Shutemov 4254c2febafcSKirill A. Shutemov pud = pud_offset(p4d, address); 4255f8ad0f49SJohannes Weiner if (pud_none(*pud) || unlikely(pud_bad(*pud))) 4256f8ad0f49SJohannes Weiner goto out; 4257f8ad0f49SJohannes Weiner 4258f8ad0f49SJohannes Weiner pmd = pmd_offset(pud, address); 4259f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 426009796395SRoss Zwisler 426109796395SRoss Zwisler if (pmd_huge(*pmd)) { 426209796395SRoss Zwisler if (!pmdpp) 4263f8ad0f49SJohannes Weiner goto out; 4264f8ad0f49SJohannes Weiner 4265a4d1a885SJérôme Glisse if (start && end) { 4266a4d1a885SJérôme Glisse *start = address & PMD_MASK; 4267a4d1a885SJérôme Glisse *end = *start + PMD_SIZE; 4268a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_start(mm, *start, *end); 4269a4d1a885SJérôme Glisse } 427009796395SRoss Zwisler *ptlp = pmd_lock(mm, pmd); 427109796395SRoss Zwisler if (pmd_huge(*pmd)) { 427209796395SRoss Zwisler *pmdpp = pmd; 427309796395SRoss Zwisler return 0; 427409796395SRoss Zwisler } 427509796395SRoss Zwisler spin_unlock(*ptlp); 4276a4d1a885SJérôme Glisse if (start && end) 4277a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_end(mm, *start, *end); 427809796395SRoss Zwisler } 427909796395SRoss Zwisler 428009796395SRoss Zwisler if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 4281f8ad0f49SJohannes Weiner goto out; 4282f8ad0f49SJohannes Weiner 4283a4d1a885SJérôme Glisse if (start && end) { 4284a4d1a885SJérôme Glisse *start = address & PAGE_MASK; 4285a4d1a885SJérôme Glisse *end = *start + PAGE_SIZE; 4286a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_start(mm, *start, *end); 4287a4d1a885SJérôme Glisse } 4288f8ad0f49SJohannes Weiner ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 4289f8ad0f49SJohannes Weiner if (!pte_present(*ptep)) 4290f8ad0f49SJohannes Weiner goto unlock; 4291f8ad0f49SJohannes Weiner *ptepp = ptep; 4292f8ad0f49SJohannes Weiner return 0; 4293f8ad0f49SJohannes Weiner unlock: 4294f8ad0f49SJohannes Weiner pte_unmap_unlock(ptep, *ptlp); 4295a4d1a885SJérôme Glisse if (start && end) 4296a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_end(mm, *start, *end); 4297f8ad0f49SJohannes Weiner out: 4298f8ad0f49SJohannes Weiner return -EINVAL; 4299f8ad0f49SJohannes Weiner } 4300f8ad0f49SJohannes Weiner 4301f729c8c9SRoss Zwisler static inline int follow_pte(struct mm_struct *mm, unsigned long address, 4302f729c8c9SRoss Zwisler pte_t **ptepp, spinlock_t **ptlp) 43031b36ba81SNamhyung Kim { 43041b36ba81SNamhyung Kim int res; 43051b36ba81SNamhyung Kim 43061b36ba81SNamhyung Kim /* (void) is needed to make gcc happy */ 43071b36ba81SNamhyung Kim (void) __cond_lock(*ptlp, 4308a4d1a885SJérôme Glisse !(res = __follow_pte_pmd(mm, address, NULL, NULL, 4309a4d1a885SJérôme Glisse ptepp, NULL, ptlp))); 43101b36ba81SNamhyung Kim return res; 43111b36ba81SNamhyung Kim } 43121b36ba81SNamhyung Kim 431309796395SRoss Zwisler int follow_pte_pmd(struct mm_struct *mm, unsigned long address, 4314a4d1a885SJérôme Glisse unsigned long *start, unsigned long *end, 431509796395SRoss Zwisler pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp) 431609796395SRoss Zwisler { 431709796395SRoss Zwisler int res; 431809796395SRoss Zwisler 431909796395SRoss Zwisler /* (void) is needed to make gcc happy */ 432009796395SRoss Zwisler (void) __cond_lock(*ptlp, 4321a4d1a885SJérôme Glisse !(res = __follow_pte_pmd(mm, address, start, end, 4322a4d1a885SJérôme Glisse ptepp, pmdpp, ptlp))); 432309796395SRoss Zwisler return res; 432409796395SRoss Zwisler } 432509796395SRoss Zwisler EXPORT_SYMBOL(follow_pte_pmd); 432609796395SRoss Zwisler 43273b6748e2SJohannes Weiner /** 43283b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 43293b6748e2SJohannes Weiner * @vma: memory mapping 43303b6748e2SJohannes Weiner * @address: user virtual address 43313b6748e2SJohannes Weiner * @pfn: location to store found PFN 43323b6748e2SJohannes Weiner * 43333b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 43343b6748e2SJohannes Weiner * 43353b6748e2SJohannes Weiner * Returns zero and the pfn at @pfn on success, -ve otherwise. 43363b6748e2SJohannes Weiner */ 43373b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 43383b6748e2SJohannes Weiner unsigned long *pfn) 43393b6748e2SJohannes Weiner { 43403b6748e2SJohannes Weiner int ret = -EINVAL; 43413b6748e2SJohannes Weiner spinlock_t *ptl; 43423b6748e2SJohannes Weiner pte_t *ptep; 43433b6748e2SJohannes Weiner 43443b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 43453b6748e2SJohannes Weiner return ret; 43463b6748e2SJohannes Weiner 43473b6748e2SJohannes Weiner ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 43483b6748e2SJohannes Weiner if (ret) 43493b6748e2SJohannes Weiner return ret; 43503b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 43513b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 43523b6748e2SJohannes Weiner return 0; 43533b6748e2SJohannes Weiner } 43543b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 43553b6748e2SJohannes Weiner 435628b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 4357d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 435828b2ee20SRik van Riel unsigned long address, unsigned int flags, 4359d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 436028b2ee20SRik van Riel { 436103668a4dSJohannes Weiner int ret = -EINVAL; 436228b2ee20SRik van Riel pte_t *ptep, pte; 436328b2ee20SRik van Riel spinlock_t *ptl; 436428b2ee20SRik van Riel 4365d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 4366d87fe660Svenkatesh.pallipadi@intel.com goto out; 436728b2ee20SRik van Riel 436803668a4dSJohannes Weiner if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 4369d87fe660Svenkatesh.pallipadi@intel.com goto out; 437028b2ee20SRik van Riel pte = *ptep; 437103668a4dSJohannes Weiner 4372f6f37321SLinus Torvalds if ((flags & FOLL_WRITE) && !pte_write(pte)) 437328b2ee20SRik van Riel goto unlock; 437428b2ee20SRik van Riel 437528b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 437603668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 437728b2ee20SRik van Riel 437803668a4dSJohannes Weiner ret = 0; 437928b2ee20SRik van Riel unlock: 438028b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 438128b2ee20SRik van Riel out: 4382d87fe660Svenkatesh.pallipadi@intel.com return ret; 438328b2ee20SRik van Riel } 438428b2ee20SRik van Riel 438528b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 438628b2ee20SRik van Riel void *buf, int len, int write) 438728b2ee20SRik van Riel { 438828b2ee20SRik van Riel resource_size_t phys_addr; 438928b2ee20SRik van Riel unsigned long prot = 0; 43902bc7273bSKOSAKI Motohiro void __iomem *maddr; 439128b2ee20SRik van Riel int offset = addr & (PAGE_SIZE-1); 439228b2ee20SRik van Riel 4393d87fe660Svenkatesh.pallipadi@intel.com if (follow_phys(vma, addr, write, &prot, &phys_addr)) 439428b2ee20SRik van Riel return -EINVAL; 439528b2ee20SRik van Riel 43969cb12d7bSGrazvydas Ignotas maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); 439728b2ee20SRik van Riel if (write) 439828b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 439928b2ee20SRik van Riel else 440028b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 440128b2ee20SRik van Riel iounmap(maddr); 440228b2ee20SRik van Riel 440328b2ee20SRik van Riel return len; 440428b2ee20SRik van Riel } 44055a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 440628b2ee20SRik van Riel #endif 440728b2ee20SRik van Riel 44080ec76a11SDavid Howells /* 4409206cb636SStephen Wilson * Access another process' address space as given in mm. If non-NULL, use the 4410206cb636SStephen Wilson * given task for page fault accounting. 44110ec76a11SDavid Howells */ 441284d77d3fSEric W. Biederman int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, 4413442486ecSLorenzo Stoakes unsigned long addr, void *buf, int len, unsigned int gup_flags) 44140ec76a11SDavid Howells { 44150ec76a11SDavid Howells struct vm_area_struct *vma; 44160ec76a11SDavid Howells void *old_buf = buf; 4417442486ecSLorenzo Stoakes int write = gup_flags & FOLL_WRITE; 44180ec76a11SDavid Howells 44190ec76a11SDavid Howells down_read(&mm->mmap_sem); 4420183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 44210ec76a11SDavid Howells while (len) { 44220ec76a11SDavid Howells int bytes, ret, offset; 44230ec76a11SDavid Howells void *maddr; 442428b2ee20SRik van Riel struct page *page = NULL; 44250ec76a11SDavid Howells 44261e987790SDave Hansen ret = get_user_pages_remote(tsk, mm, addr, 1, 44275b56d49fSLorenzo Stoakes gup_flags, &page, &vma, NULL); 442828b2ee20SRik van Riel if (ret <= 0) { 4429dbffcd03SRik van Riel #ifndef CONFIG_HAVE_IOREMAP_PROT 4430dbffcd03SRik van Riel break; 4431dbffcd03SRik van Riel #else 443228b2ee20SRik van Riel /* 443328b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 443428b2ee20SRik van Riel * we can access using slightly different code. 443528b2ee20SRik van Riel */ 443628b2ee20SRik van Riel vma = find_vma(mm, addr); 4437fe936dfcSMichael Ellerman if (!vma || vma->vm_start > addr) 44380ec76a11SDavid Howells break; 443928b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 444028b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 444128b2ee20SRik van Riel len, write); 444228b2ee20SRik van Riel if (ret <= 0) 444328b2ee20SRik van Riel break; 444428b2ee20SRik van Riel bytes = ret; 4445dbffcd03SRik van Riel #endif 444628b2ee20SRik van Riel } else { 44470ec76a11SDavid Howells bytes = len; 44480ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 44490ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 44500ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 44510ec76a11SDavid Howells 44520ec76a11SDavid Howells maddr = kmap(page); 44530ec76a11SDavid Howells if (write) { 44540ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 44550ec76a11SDavid Howells maddr + offset, buf, bytes); 44560ec76a11SDavid Howells set_page_dirty_lock(page); 44570ec76a11SDavid Howells } else { 44580ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 44590ec76a11SDavid Howells buf, maddr + offset, bytes); 44600ec76a11SDavid Howells } 44610ec76a11SDavid Howells kunmap(page); 446209cbfeafSKirill A. Shutemov put_page(page); 446328b2ee20SRik van Riel } 44640ec76a11SDavid Howells len -= bytes; 44650ec76a11SDavid Howells buf += bytes; 44660ec76a11SDavid Howells addr += bytes; 44670ec76a11SDavid Howells } 44680ec76a11SDavid Howells up_read(&mm->mmap_sem); 44690ec76a11SDavid Howells 44700ec76a11SDavid Howells return buf - old_buf; 44710ec76a11SDavid Howells } 447203252919SAndi Kleen 44735ddd36b9SStephen Wilson /** 4474ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 44755ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 44765ddd36b9SStephen Wilson * @addr: start address to access 44775ddd36b9SStephen Wilson * @buf: source or destination buffer 44785ddd36b9SStephen Wilson * @len: number of bytes to transfer 44796347e8d5SLorenzo Stoakes * @gup_flags: flags modifying lookup behaviour 44805ddd36b9SStephen Wilson * 44815ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 44825ddd36b9SStephen Wilson */ 44835ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 44846347e8d5SLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 44855ddd36b9SStephen Wilson { 44866347e8d5SLorenzo Stoakes return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags); 44875ddd36b9SStephen Wilson } 44885ddd36b9SStephen Wilson 448903252919SAndi Kleen /* 4490206cb636SStephen Wilson * Access another process' address space. 4491206cb636SStephen Wilson * Source/target buffer must be kernel space, 4492206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 4493206cb636SStephen Wilson */ 4494206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 4495f307ab6dSLorenzo Stoakes void *buf, int len, unsigned int gup_flags) 4496206cb636SStephen Wilson { 4497206cb636SStephen Wilson struct mm_struct *mm; 4498206cb636SStephen Wilson int ret; 4499206cb636SStephen Wilson 4500206cb636SStephen Wilson mm = get_task_mm(tsk); 4501206cb636SStephen Wilson if (!mm) 4502206cb636SStephen Wilson return 0; 4503206cb636SStephen Wilson 4504f307ab6dSLorenzo Stoakes ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); 4505442486ecSLorenzo Stoakes 4506206cb636SStephen Wilson mmput(mm); 4507206cb636SStephen Wilson 4508206cb636SStephen Wilson return ret; 4509206cb636SStephen Wilson } 4510fcd35857SCatalin Marinas EXPORT_SYMBOL_GPL(access_process_vm); 4511206cb636SStephen Wilson 451203252919SAndi Kleen /* 451303252919SAndi Kleen * Print the name of a VMA. 451403252919SAndi Kleen */ 451503252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 451603252919SAndi Kleen { 451703252919SAndi Kleen struct mm_struct *mm = current->mm; 451803252919SAndi Kleen struct vm_area_struct *vma; 451903252919SAndi Kleen 4520e8bff74aSIngo Molnar /* 45210a7f682dSMichal Hocko * we might be running from an atomic context so we cannot sleep 4522e8bff74aSIngo Molnar */ 45230a7f682dSMichal Hocko if (!down_read_trylock(&mm->mmap_sem)) 4524e8bff74aSIngo Molnar return; 4525e8bff74aSIngo Molnar 452603252919SAndi Kleen vma = find_vma(mm, ip); 452703252919SAndi Kleen if (vma && vma->vm_file) { 452803252919SAndi Kleen struct file *f = vma->vm_file; 45290a7f682dSMichal Hocko char *buf = (char *)__get_free_page(GFP_NOWAIT); 453003252919SAndi Kleen if (buf) { 45312fbc57c5SAndy Shevchenko char *p; 453203252919SAndi Kleen 45339bf39ab2SMiklos Szeredi p = file_path(f, buf, PAGE_SIZE); 453403252919SAndi Kleen if (IS_ERR(p)) 453503252919SAndi Kleen p = "?"; 45362fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 453703252919SAndi Kleen vma->vm_start, 453803252919SAndi Kleen vma->vm_end - vma->vm_start); 453903252919SAndi Kleen free_page((unsigned long)buf); 454003252919SAndi Kleen } 454103252919SAndi Kleen } 454251a07e50SJeff Liu up_read(&mm->mmap_sem); 454303252919SAndi Kleen } 45443ee1afa3SNick Piggin 4545662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 45469ec23531SDavid Hildenbrand void __might_fault(const char *file, int line) 45473ee1afa3SNick Piggin { 454895156f00SPeter Zijlstra /* 454995156f00SPeter Zijlstra * Some code (nfs/sunrpc) uses socket ops on kernel memory while 455095156f00SPeter Zijlstra * holding the mmap_sem, this is safe because kernel memory doesn't 455195156f00SPeter Zijlstra * get paged out, therefore we'll never actually fault, and the 455295156f00SPeter Zijlstra * below annotations will generate false positives. 455395156f00SPeter Zijlstra */ 4554db68ce10SAl Viro if (uaccess_kernel()) 455595156f00SPeter Zijlstra return; 45569ec23531SDavid Hildenbrand if (pagefault_disabled()) 4557662bbcb2SMichael S. Tsirkin return; 45589ec23531SDavid Hildenbrand __might_sleep(file, line, 0); 45599ec23531SDavid Hildenbrand #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) 4560662bbcb2SMichael S. Tsirkin if (current->mm) 45613ee1afa3SNick Piggin might_lock_read(¤t->mm->mmap_sem); 45629ec23531SDavid Hildenbrand #endif 45633ee1afa3SNick Piggin } 45649ec23531SDavid Hildenbrand EXPORT_SYMBOL(__might_fault); 45653ee1afa3SNick Piggin #endif 456647ad8475SAndrea Arcangeli 456747ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 456847ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 456947ad8475SAndrea Arcangeli unsigned long addr, 457047ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 457147ad8475SAndrea Arcangeli { 457247ad8475SAndrea Arcangeli int i; 457347ad8475SAndrea Arcangeli struct page *p = page; 457447ad8475SAndrea Arcangeli 457547ad8475SAndrea Arcangeli might_sleep(); 457647ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 457747ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 457847ad8475SAndrea Arcangeli cond_resched(); 457947ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 458047ad8475SAndrea Arcangeli } 458147ad8475SAndrea Arcangeli } 458247ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 4583c79b57e4SHuang Ying unsigned long addr_hint, unsigned int pages_per_huge_page) 458447ad8475SAndrea Arcangeli { 4585c79b57e4SHuang Ying int i, n, base, l; 4586c79b57e4SHuang Ying unsigned long addr = addr_hint & 4587c79b57e4SHuang Ying ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); 458847ad8475SAndrea Arcangeli 458947ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 459047ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 459147ad8475SAndrea Arcangeli return; 459247ad8475SAndrea Arcangeli } 459347ad8475SAndrea Arcangeli 4594c79b57e4SHuang Ying /* Clear sub-page to access last to keep its cache lines hot */ 459547ad8475SAndrea Arcangeli might_sleep(); 4596c79b57e4SHuang Ying n = (addr_hint - addr) / PAGE_SIZE; 4597c79b57e4SHuang Ying if (2 * n <= pages_per_huge_page) { 4598c79b57e4SHuang Ying /* If sub-page to access in first half of huge page */ 4599c79b57e4SHuang Ying base = 0; 4600c79b57e4SHuang Ying l = n; 4601c79b57e4SHuang Ying /* Clear sub-pages at the end of huge page */ 4602c79b57e4SHuang Ying for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { 460347ad8475SAndrea Arcangeli cond_resched(); 460447ad8475SAndrea Arcangeli clear_user_highpage(page + i, addr + i * PAGE_SIZE); 460547ad8475SAndrea Arcangeli } 4606c79b57e4SHuang Ying } else { 4607c79b57e4SHuang Ying /* If sub-page to access in second half of huge page */ 4608c79b57e4SHuang Ying base = pages_per_huge_page - 2 * (pages_per_huge_page - n); 4609c79b57e4SHuang Ying l = pages_per_huge_page - n; 4610c79b57e4SHuang Ying /* Clear sub-pages at the begin of huge page */ 4611c79b57e4SHuang Ying for (i = 0; i < base; i++) { 4612c79b57e4SHuang Ying cond_resched(); 4613c79b57e4SHuang Ying clear_user_highpage(page + i, addr + i * PAGE_SIZE); 4614c79b57e4SHuang Ying } 4615c79b57e4SHuang Ying } 4616c79b57e4SHuang Ying /* 4617c79b57e4SHuang Ying * Clear remaining sub-pages in left-right-left-right pattern 4618c79b57e4SHuang Ying * towards the sub-page to access 4619c79b57e4SHuang Ying */ 4620c79b57e4SHuang Ying for (i = 0; i < l; i++) { 4621c79b57e4SHuang Ying int left_idx = base + i; 4622c79b57e4SHuang Ying int right_idx = base + 2 * l - 1 - i; 4623c79b57e4SHuang Ying 4624c79b57e4SHuang Ying cond_resched(); 4625c79b57e4SHuang Ying clear_user_highpage(page + left_idx, 4626c79b57e4SHuang Ying addr + left_idx * PAGE_SIZE); 4627c79b57e4SHuang Ying cond_resched(); 4628c79b57e4SHuang Ying clear_user_highpage(page + right_idx, 4629c79b57e4SHuang Ying addr + right_idx * PAGE_SIZE); 4630c79b57e4SHuang Ying } 463147ad8475SAndrea Arcangeli } 463247ad8475SAndrea Arcangeli 463347ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 463447ad8475SAndrea Arcangeli unsigned long addr, 463547ad8475SAndrea Arcangeli struct vm_area_struct *vma, 463647ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 463747ad8475SAndrea Arcangeli { 463847ad8475SAndrea Arcangeli int i; 463947ad8475SAndrea Arcangeli struct page *dst_base = dst; 464047ad8475SAndrea Arcangeli struct page *src_base = src; 464147ad8475SAndrea Arcangeli 464247ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 464347ad8475SAndrea Arcangeli cond_resched(); 464447ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 464547ad8475SAndrea Arcangeli 464647ad8475SAndrea Arcangeli i++; 464747ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 464847ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 464947ad8475SAndrea Arcangeli } 465047ad8475SAndrea Arcangeli } 465147ad8475SAndrea Arcangeli 465247ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 465347ad8475SAndrea Arcangeli unsigned long addr, struct vm_area_struct *vma, 465447ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 465547ad8475SAndrea Arcangeli { 465647ad8475SAndrea Arcangeli int i; 465747ad8475SAndrea Arcangeli 465847ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 465947ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 466047ad8475SAndrea Arcangeli pages_per_huge_page); 466147ad8475SAndrea Arcangeli return; 466247ad8475SAndrea Arcangeli } 466347ad8475SAndrea Arcangeli 466447ad8475SAndrea Arcangeli might_sleep(); 466547ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; i++) { 466647ad8475SAndrea Arcangeli cond_resched(); 466747ad8475SAndrea Arcangeli copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 466847ad8475SAndrea Arcangeli } 466947ad8475SAndrea Arcangeli } 4670fa4d75c1SMike Kravetz 4671fa4d75c1SMike Kravetz long copy_huge_page_from_user(struct page *dst_page, 4672fa4d75c1SMike Kravetz const void __user *usr_src, 4673810a56b9SMike Kravetz unsigned int pages_per_huge_page, 4674810a56b9SMike Kravetz bool allow_pagefault) 4675fa4d75c1SMike Kravetz { 4676fa4d75c1SMike Kravetz void *src = (void *)usr_src; 4677fa4d75c1SMike Kravetz void *page_kaddr; 4678fa4d75c1SMike Kravetz unsigned long i, rc = 0; 4679fa4d75c1SMike Kravetz unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; 4680fa4d75c1SMike Kravetz 4681fa4d75c1SMike Kravetz for (i = 0; i < pages_per_huge_page; i++) { 4682810a56b9SMike Kravetz if (allow_pagefault) 4683810a56b9SMike Kravetz page_kaddr = kmap(dst_page + i); 4684810a56b9SMike Kravetz else 4685fa4d75c1SMike Kravetz page_kaddr = kmap_atomic(dst_page + i); 4686fa4d75c1SMike Kravetz rc = copy_from_user(page_kaddr, 4687fa4d75c1SMike Kravetz (const void __user *)(src + i * PAGE_SIZE), 4688fa4d75c1SMike Kravetz PAGE_SIZE); 4689810a56b9SMike Kravetz if (allow_pagefault) 4690810a56b9SMike Kravetz kunmap(dst_page + i); 4691810a56b9SMike Kravetz else 4692fa4d75c1SMike Kravetz kunmap_atomic(page_kaddr); 4693fa4d75c1SMike Kravetz 4694fa4d75c1SMike Kravetz ret_val -= (PAGE_SIZE - rc); 4695fa4d75c1SMike Kravetz if (rc) 4696fa4d75c1SMike Kravetz break; 4697fa4d75c1SMike Kravetz 4698fa4d75c1SMike Kravetz cond_resched(); 4699fa4d75c1SMike Kravetz } 4700fa4d75c1SMike Kravetz return ret_val; 4701fa4d75c1SMike Kravetz } 470247ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 470349076ec2SKirill A. Shutemov 470440b64acdSOlof Johansson #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS 4705b35f1819SKirill A. Shutemov 4706b35f1819SKirill A. Shutemov static struct kmem_cache *page_ptl_cachep; 4707b35f1819SKirill A. Shutemov 4708b35f1819SKirill A. Shutemov void __init ptlock_cache_init(void) 4709b35f1819SKirill A. Shutemov { 4710b35f1819SKirill A. Shutemov page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, 4711b35f1819SKirill A. Shutemov SLAB_PANIC, NULL); 4712b35f1819SKirill A. Shutemov } 4713b35f1819SKirill A. Shutemov 4714539edb58SPeter Zijlstra bool ptlock_alloc(struct page *page) 471549076ec2SKirill A. Shutemov { 471649076ec2SKirill A. Shutemov spinlock_t *ptl; 471749076ec2SKirill A. Shutemov 4718b35f1819SKirill A. Shutemov ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); 471949076ec2SKirill A. Shutemov if (!ptl) 472049076ec2SKirill A. Shutemov return false; 4721539edb58SPeter Zijlstra page->ptl = ptl; 472249076ec2SKirill A. Shutemov return true; 472349076ec2SKirill A. Shutemov } 472449076ec2SKirill A. Shutemov 4725539edb58SPeter Zijlstra void ptlock_free(struct page *page) 472649076ec2SKirill A. Shutemov { 4727b35f1819SKirill A. Shutemov kmem_cache_free(page_ptl_cachep, page->ptl); 472849076ec2SKirill A. Shutemov } 472949076ec2SKirill A. Shutemov #endif 4730