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> 431da177e4SLinus Torvalds #include <linux/hugetlb.h> 441da177e4SLinus Torvalds #include <linux/mman.h> 451da177e4SLinus Torvalds #include <linux/swap.h> 461da177e4SLinus Torvalds #include <linux/highmem.h> 471da177e4SLinus Torvalds #include <linux/pagemap.h> 489a840895SHugh Dickins #include <linux/ksm.h> 491da177e4SLinus Torvalds #include <linux/rmap.h> 50b95f1b31SPaul Gortmaker #include <linux/export.h> 510ff92245SShailabh Nagar #include <linux/delayacct.h> 521da177e4SLinus Torvalds #include <linux/init.h> 53edc79b2aSPeter Zijlstra #include <linux/writeback.h> 548a9f3ccdSBalbir Singh #include <linux/memcontrol.h> 55cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 563dc14741SHugh Dickins #include <linux/kallsyms.h> 573dc14741SHugh Dickins #include <linux/swapops.h> 583dc14741SHugh Dickins #include <linux/elf.h> 595a0e3ad6STejun Heo #include <linux/gfp.h> 604daae3b4SMel Gorman #include <linux/migrate.h> 612fbc57c5SAndy Shevchenko #include <linux/string.h> 621da177e4SLinus Torvalds 636952b61dSAlexey Dobriyan #include <asm/io.h> 641da177e4SLinus Torvalds #include <asm/pgalloc.h> 651da177e4SLinus Torvalds #include <asm/uaccess.h> 661da177e4SLinus Torvalds #include <asm/tlb.h> 671da177e4SLinus Torvalds #include <asm/tlbflush.h> 681da177e4SLinus Torvalds #include <asm/pgtable.h> 691da177e4SLinus Torvalds 7042b77728SJan Beulich #include "internal.h" 7142b77728SJan Beulich 7275980e97SPeter Zijlstra #ifdef LAST_NID_NOT_IN_PAGE_FLAGS 7375980e97SPeter Zijlstra #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_nid. 7475980e97SPeter Zijlstra #endif 7575980e97SPeter Zijlstra 76d41dee36SAndy Whitcroft #ifndef CONFIG_NEED_MULTIPLE_NODES 771da177e4SLinus Torvalds /* use the per-pgdat data instead for discontigmem - mbligh */ 781da177e4SLinus Torvalds unsigned long max_mapnr; 791da177e4SLinus Torvalds struct page *mem_map; 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 821da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 831da177e4SLinus Torvalds #endif 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds /* 861da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 871da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 881da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 891da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 901da177e4SLinus Torvalds * and ZONE_HIGHMEM. 911da177e4SLinus Torvalds */ 921da177e4SLinus Torvalds void * high_memory; 931da177e4SLinus Torvalds 941da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 951da177e4SLinus Torvalds 9632a93233SIngo Molnar /* 9732a93233SIngo Molnar * Randomize the address space (stacks, mmaps, brk, etc.). 9832a93233SIngo Molnar * 9932a93233SIngo Molnar * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, 10032a93233SIngo Molnar * as ancient (libc5 based) binaries can segfault. ) 10132a93233SIngo Molnar */ 10232a93233SIngo Molnar int randomize_va_space __read_mostly = 10332a93233SIngo Molnar #ifdef CONFIG_COMPAT_BRK 10432a93233SIngo Molnar 1; 10532a93233SIngo Molnar #else 10632a93233SIngo Molnar 2; 10732a93233SIngo Molnar #endif 108a62eaf15SAndi Kleen 109a62eaf15SAndi Kleen static int __init disable_randmaps(char *s) 110a62eaf15SAndi Kleen { 111a62eaf15SAndi Kleen randomize_va_space = 0; 1129b41046cSOGAWA Hirofumi return 1; 113a62eaf15SAndi Kleen } 114a62eaf15SAndi Kleen __setup("norandmaps", disable_randmaps); 115a62eaf15SAndi Kleen 11662eede62SHugh Dickins unsigned long zero_pfn __read_mostly; 11703f6462aSHugh Dickins unsigned long highest_memmap_pfn __read_mostly; 118a13ea5b7SHugh Dickins 119a13ea5b7SHugh Dickins /* 120a13ea5b7SHugh Dickins * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() 121a13ea5b7SHugh Dickins */ 122a13ea5b7SHugh Dickins static int __init init_zero_pfn(void) 123a13ea5b7SHugh Dickins { 124a13ea5b7SHugh Dickins zero_pfn = page_to_pfn(ZERO_PAGE(0)); 125a13ea5b7SHugh Dickins return 0; 126a13ea5b7SHugh Dickins } 127a13ea5b7SHugh Dickins core_initcall(init_zero_pfn); 128a62eaf15SAndi Kleen 129d559db08SKAMEZAWA Hiroyuki 13034e55232SKAMEZAWA Hiroyuki #if defined(SPLIT_RSS_COUNTING) 13134e55232SKAMEZAWA Hiroyuki 132ea48cf78SDavid Rientjes void sync_mm_rss(struct mm_struct *mm) 13334e55232SKAMEZAWA Hiroyuki { 13434e55232SKAMEZAWA Hiroyuki int i; 13534e55232SKAMEZAWA Hiroyuki 13634e55232SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) { 13705af2e10SDavid Rientjes if (current->rss_stat.count[i]) { 13805af2e10SDavid Rientjes add_mm_counter(mm, i, current->rss_stat.count[i]); 13905af2e10SDavid Rientjes current->rss_stat.count[i] = 0; 14034e55232SKAMEZAWA Hiroyuki } 14134e55232SKAMEZAWA Hiroyuki } 14205af2e10SDavid Rientjes current->rss_stat.events = 0; 14334e55232SKAMEZAWA Hiroyuki } 14434e55232SKAMEZAWA Hiroyuki 14534e55232SKAMEZAWA Hiroyuki static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) 14634e55232SKAMEZAWA Hiroyuki { 14734e55232SKAMEZAWA Hiroyuki struct task_struct *task = current; 14834e55232SKAMEZAWA Hiroyuki 14934e55232SKAMEZAWA Hiroyuki if (likely(task->mm == mm)) 15034e55232SKAMEZAWA Hiroyuki task->rss_stat.count[member] += val; 15134e55232SKAMEZAWA Hiroyuki else 15234e55232SKAMEZAWA Hiroyuki add_mm_counter(mm, member, val); 15334e55232SKAMEZAWA Hiroyuki } 15434e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) 15534e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) 15634e55232SKAMEZAWA Hiroyuki 15734e55232SKAMEZAWA Hiroyuki /* sync counter once per 64 page faults */ 15834e55232SKAMEZAWA Hiroyuki #define TASK_RSS_EVENTS_THRESH (64) 15934e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 16034e55232SKAMEZAWA Hiroyuki { 16134e55232SKAMEZAWA Hiroyuki if (unlikely(task != current)) 16234e55232SKAMEZAWA Hiroyuki return; 16334e55232SKAMEZAWA Hiroyuki if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) 164ea48cf78SDavid Rientjes sync_mm_rss(task->mm); 16534e55232SKAMEZAWA Hiroyuki } 1669547d01bSPeter Zijlstra #else /* SPLIT_RSS_COUNTING */ 16734e55232SKAMEZAWA Hiroyuki 16834e55232SKAMEZAWA Hiroyuki #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) 16934e55232SKAMEZAWA Hiroyuki #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) 17034e55232SKAMEZAWA Hiroyuki 17134e55232SKAMEZAWA Hiroyuki static void check_sync_rss_stat(struct task_struct *task) 17234e55232SKAMEZAWA Hiroyuki { 17334e55232SKAMEZAWA Hiroyuki } 17434e55232SKAMEZAWA Hiroyuki 1759547d01bSPeter Zijlstra #endif /* SPLIT_RSS_COUNTING */ 1769547d01bSPeter Zijlstra 1779547d01bSPeter Zijlstra #ifdef HAVE_GENERIC_MMU_GATHER 1789547d01bSPeter Zijlstra 1799547d01bSPeter Zijlstra static int tlb_next_batch(struct mmu_gather *tlb) 1809547d01bSPeter Zijlstra { 1819547d01bSPeter Zijlstra struct mmu_gather_batch *batch; 1829547d01bSPeter Zijlstra 1839547d01bSPeter Zijlstra batch = tlb->active; 1849547d01bSPeter Zijlstra if (batch->next) { 1859547d01bSPeter Zijlstra tlb->active = batch->next; 1869547d01bSPeter Zijlstra return 1; 1879547d01bSPeter Zijlstra } 1889547d01bSPeter Zijlstra 18953a59fc6SMichal Hocko if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) 19053a59fc6SMichal Hocko return 0; 19153a59fc6SMichal Hocko 1929547d01bSPeter Zijlstra batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); 1939547d01bSPeter Zijlstra if (!batch) 1949547d01bSPeter Zijlstra return 0; 1959547d01bSPeter Zijlstra 19653a59fc6SMichal Hocko tlb->batch_count++; 1979547d01bSPeter Zijlstra batch->next = NULL; 1989547d01bSPeter Zijlstra batch->nr = 0; 1999547d01bSPeter Zijlstra batch->max = MAX_GATHER_BATCH; 2009547d01bSPeter Zijlstra 2019547d01bSPeter Zijlstra tlb->active->next = batch; 2029547d01bSPeter Zijlstra tlb->active = batch; 2039547d01bSPeter Zijlstra 2049547d01bSPeter Zijlstra return 1; 2059547d01bSPeter Zijlstra } 2069547d01bSPeter Zijlstra 2079547d01bSPeter Zijlstra /* tlb_gather_mmu 2089547d01bSPeter Zijlstra * Called to initialize an (on-stack) mmu_gather structure for page-table 2099547d01bSPeter Zijlstra * tear-down from @mm. The @fullmm argument is used when @mm is without 2109547d01bSPeter Zijlstra * users and we're going to destroy the full address space (exit/execve). 2119547d01bSPeter Zijlstra */ 2122b047252SLinus Torvalds void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end) 2139547d01bSPeter Zijlstra { 2149547d01bSPeter Zijlstra tlb->mm = mm; 2159547d01bSPeter Zijlstra 2162b047252SLinus Torvalds /* Is it from 0 to ~0? */ 2172b047252SLinus Torvalds tlb->fullmm = !(start | (end+1)); 2181de14c3cSDave Hansen tlb->need_flush_all = 0; 2192b047252SLinus Torvalds tlb->start = start; 2202b047252SLinus Torvalds tlb->end = end; 2219547d01bSPeter Zijlstra tlb->need_flush = 0; 2229547d01bSPeter Zijlstra tlb->local.next = NULL; 2239547d01bSPeter Zijlstra tlb->local.nr = 0; 2249547d01bSPeter Zijlstra tlb->local.max = ARRAY_SIZE(tlb->__pages); 2259547d01bSPeter Zijlstra tlb->active = &tlb->local; 22653a59fc6SMichal Hocko tlb->batch_count = 0; 2279547d01bSPeter Zijlstra 2289547d01bSPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 2299547d01bSPeter Zijlstra tlb->batch = NULL; 23034e55232SKAMEZAWA Hiroyuki #endif 2319547d01bSPeter Zijlstra } 2329547d01bSPeter Zijlstra 2339547d01bSPeter Zijlstra void tlb_flush_mmu(struct mmu_gather *tlb) 2349547d01bSPeter Zijlstra { 2359547d01bSPeter Zijlstra struct mmu_gather_batch *batch; 2369547d01bSPeter Zijlstra 2379547d01bSPeter Zijlstra if (!tlb->need_flush) 2389547d01bSPeter Zijlstra return; 2399547d01bSPeter Zijlstra tlb->need_flush = 0; 2409547d01bSPeter Zijlstra tlb_flush(tlb); 2419547d01bSPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 2429547d01bSPeter Zijlstra tlb_table_flush(tlb); 2439547d01bSPeter Zijlstra #endif 2449547d01bSPeter Zijlstra 2459547d01bSPeter Zijlstra for (batch = &tlb->local; batch; batch = batch->next) { 2469547d01bSPeter Zijlstra free_pages_and_swap_cache(batch->pages, batch->nr); 2479547d01bSPeter Zijlstra batch->nr = 0; 2489547d01bSPeter Zijlstra } 2499547d01bSPeter Zijlstra tlb->active = &tlb->local; 2509547d01bSPeter Zijlstra } 2519547d01bSPeter Zijlstra 2529547d01bSPeter Zijlstra /* tlb_finish_mmu 2539547d01bSPeter Zijlstra * Called at the end of the shootdown operation to free up any resources 2549547d01bSPeter Zijlstra * that were required. 2559547d01bSPeter Zijlstra */ 2569547d01bSPeter Zijlstra void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) 2579547d01bSPeter Zijlstra { 2589547d01bSPeter Zijlstra struct mmu_gather_batch *batch, *next; 2599547d01bSPeter Zijlstra 2609547d01bSPeter Zijlstra tlb_flush_mmu(tlb); 2619547d01bSPeter Zijlstra 2629547d01bSPeter Zijlstra /* keep the page table cache within bounds */ 2639547d01bSPeter Zijlstra check_pgt_cache(); 2649547d01bSPeter Zijlstra 2659547d01bSPeter Zijlstra for (batch = tlb->local.next; batch; batch = next) { 2669547d01bSPeter Zijlstra next = batch->next; 2679547d01bSPeter Zijlstra free_pages((unsigned long)batch, 0); 2689547d01bSPeter Zijlstra } 2699547d01bSPeter Zijlstra tlb->local.next = NULL; 2709547d01bSPeter Zijlstra } 2719547d01bSPeter Zijlstra 2729547d01bSPeter Zijlstra /* __tlb_remove_page 2739547d01bSPeter Zijlstra * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while 2749547d01bSPeter Zijlstra * handling the additional races in SMP caused by other CPUs caching valid 2759547d01bSPeter Zijlstra * mappings in their TLBs. Returns the number of free page slots left. 2769547d01bSPeter Zijlstra * When out of page slots we must call tlb_flush_mmu(). 2779547d01bSPeter Zijlstra */ 2789547d01bSPeter Zijlstra int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) 2799547d01bSPeter Zijlstra { 2809547d01bSPeter Zijlstra struct mmu_gather_batch *batch; 2819547d01bSPeter Zijlstra 282f21760b1SShaohua Li VM_BUG_ON(!tlb->need_flush); 2839547d01bSPeter Zijlstra 2849547d01bSPeter Zijlstra batch = tlb->active; 2859547d01bSPeter Zijlstra batch->pages[batch->nr++] = page; 2869547d01bSPeter Zijlstra if (batch->nr == batch->max) { 2879547d01bSPeter Zijlstra if (!tlb_next_batch(tlb)) 2889547d01bSPeter Zijlstra return 0; 2890b43c3aaSShaohua Li batch = tlb->active; 2909547d01bSPeter Zijlstra } 2919547d01bSPeter Zijlstra VM_BUG_ON(batch->nr > batch->max); 2929547d01bSPeter Zijlstra 2939547d01bSPeter Zijlstra return batch->max - batch->nr; 2949547d01bSPeter Zijlstra } 2959547d01bSPeter Zijlstra 2969547d01bSPeter Zijlstra #endif /* HAVE_GENERIC_MMU_GATHER */ 29734e55232SKAMEZAWA Hiroyuki 29826723911SPeter Zijlstra #ifdef CONFIG_HAVE_RCU_TABLE_FREE 29926723911SPeter Zijlstra 30026723911SPeter Zijlstra /* 30126723911SPeter Zijlstra * See the comment near struct mmu_table_batch. 30226723911SPeter Zijlstra */ 30326723911SPeter Zijlstra 30426723911SPeter Zijlstra static void tlb_remove_table_smp_sync(void *arg) 30526723911SPeter Zijlstra { 30626723911SPeter Zijlstra /* Simply deliver the interrupt */ 30726723911SPeter Zijlstra } 30826723911SPeter Zijlstra 30926723911SPeter Zijlstra static void tlb_remove_table_one(void *table) 31026723911SPeter Zijlstra { 31126723911SPeter Zijlstra /* 31226723911SPeter Zijlstra * This isn't an RCU grace period and hence the page-tables cannot be 31326723911SPeter Zijlstra * assumed to be actually RCU-freed. 31426723911SPeter Zijlstra * 31526723911SPeter Zijlstra * It is however sufficient for software page-table walkers that rely on 31626723911SPeter Zijlstra * IRQ disabling. See the comment near struct mmu_table_batch. 31726723911SPeter Zijlstra */ 31826723911SPeter Zijlstra smp_call_function(tlb_remove_table_smp_sync, NULL, 1); 31926723911SPeter Zijlstra __tlb_remove_table(table); 32026723911SPeter Zijlstra } 32126723911SPeter Zijlstra 32226723911SPeter Zijlstra static void tlb_remove_table_rcu(struct rcu_head *head) 32326723911SPeter Zijlstra { 32426723911SPeter Zijlstra struct mmu_table_batch *batch; 32526723911SPeter Zijlstra int i; 32626723911SPeter Zijlstra 32726723911SPeter Zijlstra batch = container_of(head, struct mmu_table_batch, rcu); 32826723911SPeter Zijlstra 32926723911SPeter Zijlstra for (i = 0; i < batch->nr; i++) 33026723911SPeter Zijlstra __tlb_remove_table(batch->tables[i]); 33126723911SPeter Zijlstra 33226723911SPeter Zijlstra free_page((unsigned long)batch); 33326723911SPeter Zijlstra } 33426723911SPeter Zijlstra 33526723911SPeter Zijlstra void tlb_table_flush(struct mmu_gather *tlb) 33626723911SPeter Zijlstra { 33726723911SPeter Zijlstra struct mmu_table_batch **batch = &tlb->batch; 33826723911SPeter Zijlstra 33926723911SPeter Zijlstra if (*batch) { 34026723911SPeter Zijlstra call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); 34126723911SPeter Zijlstra *batch = NULL; 34226723911SPeter Zijlstra } 34326723911SPeter Zijlstra } 34426723911SPeter Zijlstra 34526723911SPeter Zijlstra void tlb_remove_table(struct mmu_gather *tlb, void *table) 34626723911SPeter Zijlstra { 34726723911SPeter Zijlstra struct mmu_table_batch **batch = &tlb->batch; 34826723911SPeter Zijlstra 34926723911SPeter Zijlstra tlb->need_flush = 1; 35026723911SPeter Zijlstra 35126723911SPeter Zijlstra /* 35226723911SPeter Zijlstra * When there's less then two users of this mm there cannot be a 35326723911SPeter Zijlstra * concurrent page-table walk. 35426723911SPeter Zijlstra */ 35526723911SPeter Zijlstra if (atomic_read(&tlb->mm->mm_users) < 2) { 35626723911SPeter Zijlstra __tlb_remove_table(table); 35726723911SPeter Zijlstra return; 35826723911SPeter Zijlstra } 35926723911SPeter Zijlstra 36026723911SPeter Zijlstra if (*batch == NULL) { 36126723911SPeter Zijlstra *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); 36226723911SPeter Zijlstra if (*batch == NULL) { 36326723911SPeter Zijlstra tlb_remove_table_one(table); 36426723911SPeter Zijlstra return; 36526723911SPeter Zijlstra } 36626723911SPeter Zijlstra (*batch)->nr = 0; 36726723911SPeter Zijlstra } 36826723911SPeter Zijlstra (*batch)->tables[(*batch)->nr++] = table; 36926723911SPeter Zijlstra if ((*batch)->nr == MAX_TABLE_BATCH) 37026723911SPeter Zijlstra tlb_table_flush(tlb); 37126723911SPeter Zijlstra } 37226723911SPeter Zijlstra 3739547d01bSPeter Zijlstra #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ 37426723911SPeter Zijlstra 3751da177e4SLinus Torvalds /* 3761da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 3771da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 3781da177e4SLinus Torvalds */ 3799e1b32caSBenjamin Herrenschmidt static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 3809e1b32caSBenjamin Herrenschmidt unsigned long addr) 3811da177e4SLinus Torvalds { 3822f569afdSMartin Schwidefsky pgtable_t token = pmd_pgtable(*pmd); 3831da177e4SLinus Torvalds pmd_clear(pmd); 3849e1b32caSBenjamin Herrenschmidt pte_free_tlb(tlb, token, addr); 3851da177e4SLinus Torvalds tlb->mm->nr_ptes--; 3861da177e4SLinus Torvalds } 3871da177e4SLinus Torvalds 388e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 389e0da382cSHugh Dickins unsigned long addr, unsigned long end, 390e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 3911da177e4SLinus Torvalds { 3921da177e4SLinus Torvalds pmd_t *pmd; 3931da177e4SLinus Torvalds unsigned long next; 394e0da382cSHugh Dickins unsigned long start; 3951da177e4SLinus Torvalds 396e0da382cSHugh Dickins start = addr; 3971da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 3981da177e4SLinus Torvalds do { 3991da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 4001da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 4011da177e4SLinus Torvalds continue; 4029e1b32caSBenjamin Herrenschmidt free_pte_range(tlb, pmd, addr); 4031da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 4041da177e4SLinus Torvalds 405e0da382cSHugh Dickins start &= PUD_MASK; 406e0da382cSHugh Dickins if (start < floor) 407e0da382cSHugh Dickins return; 408e0da382cSHugh Dickins if (ceiling) { 409e0da382cSHugh Dickins ceiling &= PUD_MASK; 410e0da382cSHugh Dickins if (!ceiling) 411e0da382cSHugh Dickins return; 4121da177e4SLinus Torvalds } 413e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 414e0da382cSHugh Dickins return; 415e0da382cSHugh Dickins 416e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 417e0da382cSHugh Dickins pud_clear(pud); 4189e1b32caSBenjamin Herrenschmidt pmd_free_tlb(tlb, pmd, start); 4191da177e4SLinus Torvalds } 4201da177e4SLinus Torvalds 421e0da382cSHugh Dickins static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 422e0da382cSHugh Dickins unsigned long addr, unsigned long end, 423e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 4241da177e4SLinus Torvalds { 4251da177e4SLinus Torvalds pud_t *pud; 4261da177e4SLinus Torvalds unsigned long next; 427e0da382cSHugh Dickins unsigned long start; 4281da177e4SLinus Torvalds 429e0da382cSHugh Dickins start = addr; 4301da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 4311da177e4SLinus Torvalds do { 4321da177e4SLinus Torvalds next = pud_addr_end(addr, end); 4331da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 4341da177e4SLinus Torvalds continue; 435e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 4361da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 4371da177e4SLinus Torvalds 438e0da382cSHugh Dickins start &= PGDIR_MASK; 439e0da382cSHugh Dickins if (start < floor) 440e0da382cSHugh Dickins return; 441e0da382cSHugh Dickins if (ceiling) { 442e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 443e0da382cSHugh Dickins if (!ceiling) 444e0da382cSHugh Dickins return; 4451da177e4SLinus Torvalds } 446e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 447e0da382cSHugh Dickins return; 448e0da382cSHugh Dickins 449e0da382cSHugh Dickins pud = pud_offset(pgd, start); 450e0da382cSHugh Dickins pgd_clear(pgd); 4519e1b32caSBenjamin Herrenschmidt pud_free_tlb(tlb, pud, start); 4521da177e4SLinus Torvalds } 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds /* 455e0da382cSHugh Dickins * This function frees user-level page tables of a process. 456e0da382cSHugh Dickins * 4571da177e4SLinus Torvalds * Must be called with pagetable lock held. 4581da177e4SLinus Torvalds */ 45942b77728SJan Beulich void free_pgd_range(struct mmu_gather *tlb, 460e0da382cSHugh Dickins unsigned long addr, unsigned long end, 461e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 4621da177e4SLinus Torvalds { 4631da177e4SLinus Torvalds pgd_t *pgd; 4641da177e4SLinus Torvalds unsigned long next; 4651da177e4SLinus Torvalds 466e0da382cSHugh Dickins /* 467e0da382cSHugh Dickins * The next few lines have given us lots of grief... 468e0da382cSHugh Dickins * 469e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 470e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 471e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 472e0da382cSHugh Dickins * 473e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 474e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 475e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 476e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 477e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 478e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 479e0da382cSHugh Dickins * that end 0 case should be mythical). 480e0da382cSHugh Dickins * 481e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 482e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 483e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 484e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 485e0da382cSHugh Dickins * 486e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 487e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 488e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 489e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 490e0da382cSHugh Dickins */ 491e0da382cSHugh Dickins 492e0da382cSHugh Dickins addr &= PMD_MASK; 493e0da382cSHugh Dickins if (addr < floor) { 494e0da382cSHugh Dickins addr += PMD_SIZE; 495e0da382cSHugh Dickins if (!addr) 496e0da382cSHugh Dickins return; 497e0da382cSHugh Dickins } 498e0da382cSHugh Dickins if (ceiling) { 499e0da382cSHugh Dickins ceiling &= PMD_MASK; 500e0da382cSHugh Dickins if (!ceiling) 501e0da382cSHugh Dickins return; 502e0da382cSHugh Dickins } 503e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 504e0da382cSHugh Dickins end -= PMD_SIZE; 505e0da382cSHugh Dickins if (addr > end - 1) 506e0da382cSHugh Dickins return; 507e0da382cSHugh Dickins 50842b77728SJan Beulich pgd = pgd_offset(tlb->mm, addr); 5091da177e4SLinus Torvalds do { 5101da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 5111da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 5121da177e4SLinus Torvalds continue; 51342b77728SJan Beulich free_pud_range(tlb, pgd, addr, next, floor, ceiling); 5141da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 515e0da382cSHugh Dickins } 516e0da382cSHugh Dickins 51742b77728SJan Beulich void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, 518e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 519e0da382cSHugh Dickins { 520e0da382cSHugh Dickins while (vma) { 521e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 522e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 523e0da382cSHugh Dickins 5248f4f8c16SHugh Dickins /* 52525d9e2d1Snpiggin@suse.de * Hide vma from rmap and truncate_pagecache before freeing 52625d9e2d1Snpiggin@suse.de * pgtables 5278f4f8c16SHugh Dickins */ 5285beb4930SRik van Riel unlink_anon_vmas(vma); 5298f4f8c16SHugh Dickins unlink_file_vma(vma); 5308f4f8c16SHugh Dickins 5319da61aefSDavid Gibson if (is_vm_hugetlb_page(vma)) { 5323bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 5333bf5ee95SHugh Dickins floor, next? next->vm_start: ceiling); 5343bf5ee95SHugh Dickins } else { 5353bf5ee95SHugh Dickins /* 5363bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 5373bf5ee95SHugh Dickins */ 5383bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 5394866920bSDavid Gibson && !is_vm_hugetlb_page(next)) { 540e0da382cSHugh Dickins vma = next; 541e0da382cSHugh Dickins next = vma->vm_next; 5425beb4930SRik van Riel unlink_anon_vmas(vma); 5438f4f8c16SHugh Dickins unlink_file_vma(vma); 544e0da382cSHugh Dickins } 5453bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 546e0da382cSHugh Dickins floor, next? next->vm_start: ceiling); 5473bf5ee95SHugh Dickins } 548e0da382cSHugh Dickins vma = next; 549e0da382cSHugh Dickins } 5501da177e4SLinus Torvalds } 5511da177e4SLinus Torvalds 5528ac1f832SAndrea Arcangeli int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, 5538ac1f832SAndrea Arcangeli pmd_t *pmd, unsigned long address) 5541da177e4SLinus Torvalds { 5552f569afdSMartin Schwidefsky pgtable_t new = pte_alloc_one(mm, address); 5568ac1f832SAndrea Arcangeli int wait_split_huge_page; 5571da177e4SLinus Torvalds if (!new) 5581bb3630eSHugh Dickins return -ENOMEM; 5591bb3630eSHugh Dickins 560362a61adSNick Piggin /* 561362a61adSNick Piggin * Ensure all pte setup (eg. pte page lock and page clearing) are 562362a61adSNick Piggin * visible before the pte is made visible to other CPUs by being 563362a61adSNick Piggin * put into page tables. 564362a61adSNick Piggin * 565362a61adSNick Piggin * The other side of the story is the pointer chasing in the page 566362a61adSNick Piggin * table walking code (when walking the page table without locking; 567362a61adSNick Piggin * ie. most of the time). Fortunately, these data accesses consist 568362a61adSNick Piggin * of a chain of data-dependent loads, meaning most CPUs (alpha 569362a61adSNick Piggin * being the notable exception) will already guarantee loads are 570362a61adSNick Piggin * seen in-order. See the alpha page table accessors for the 571362a61adSNick Piggin * smp_read_barrier_depends() barriers in page table walking code. 572362a61adSNick Piggin */ 573362a61adSNick Piggin smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ 574362a61adSNick Piggin 575c74df32cSHugh Dickins spin_lock(&mm->page_table_lock); 5768ac1f832SAndrea Arcangeli wait_split_huge_page = 0; 5778ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 5781da177e4SLinus Torvalds mm->nr_ptes++; 5791da177e4SLinus Torvalds pmd_populate(mm, pmd, new); 5802f569afdSMartin Schwidefsky new = NULL; 5818ac1f832SAndrea Arcangeli } else if (unlikely(pmd_trans_splitting(*pmd))) 5828ac1f832SAndrea Arcangeli wait_split_huge_page = 1; 583c74df32cSHugh Dickins spin_unlock(&mm->page_table_lock); 5842f569afdSMartin Schwidefsky if (new) 5852f569afdSMartin Schwidefsky pte_free(mm, new); 5868ac1f832SAndrea Arcangeli if (wait_split_huge_page) 5878ac1f832SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, pmd); 5881bb3630eSHugh Dickins return 0; 5891da177e4SLinus Torvalds } 5901da177e4SLinus Torvalds 5911bb3630eSHugh Dickins int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) 5921da177e4SLinus Torvalds { 5931bb3630eSHugh Dickins pte_t *new = pte_alloc_one_kernel(&init_mm, address); 5941da177e4SLinus Torvalds if (!new) 5951bb3630eSHugh Dickins return -ENOMEM; 5961da177e4SLinus Torvalds 597362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 598362a61adSNick Piggin 599872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 6008ac1f832SAndrea Arcangeli if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ 601872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 6022f569afdSMartin Schwidefsky new = NULL; 6038ac1f832SAndrea Arcangeli } else 6048ac1f832SAndrea Arcangeli VM_BUG_ON(pmd_trans_splitting(*pmd)); 605872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 6062f569afdSMartin Schwidefsky if (new) 6072f569afdSMartin Schwidefsky pte_free_kernel(&init_mm, new); 6081bb3630eSHugh Dickins return 0; 6091da177e4SLinus Torvalds } 6101da177e4SLinus Torvalds 611d559db08SKAMEZAWA Hiroyuki static inline void init_rss_vec(int *rss) 612ae859762SHugh Dickins { 613d559db08SKAMEZAWA Hiroyuki memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); 614d559db08SKAMEZAWA Hiroyuki } 615d559db08SKAMEZAWA Hiroyuki 616d559db08SKAMEZAWA Hiroyuki static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) 617d559db08SKAMEZAWA Hiroyuki { 618d559db08SKAMEZAWA Hiroyuki int i; 619d559db08SKAMEZAWA Hiroyuki 62034e55232SKAMEZAWA Hiroyuki if (current->mm == mm) 62105af2e10SDavid Rientjes sync_mm_rss(mm); 622d559db08SKAMEZAWA Hiroyuki for (i = 0; i < NR_MM_COUNTERS; i++) 623d559db08SKAMEZAWA Hiroyuki if (rss[i]) 624d559db08SKAMEZAWA Hiroyuki add_mm_counter(mm, i, rss[i]); 625ae859762SHugh Dickins } 626ae859762SHugh Dickins 6271da177e4SLinus Torvalds /* 6286aab341eSLinus Torvalds * This function is called to print an error when a bad pte 6296aab341eSLinus Torvalds * is found. For example, we might have a PFN-mapped pte in 6306aab341eSLinus Torvalds * a region that doesn't allow it. 631b5810039SNick Piggin * 632b5810039SNick Piggin * The calling function must still handle the error. 633b5810039SNick Piggin */ 6343dc14741SHugh Dickins static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 6353dc14741SHugh Dickins pte_t pte, struct page *page) 636b5810039SNick Piggin { 6373dc14741SHugh Dickins pgd_t *pgd = pgd_offset(vma->vm_mm, addr); 6383dc14741SHugh Dickins pud_t *pud = pud_offset(pgd, addr); 6393dc14741SHugh Dickins pmd_t *pmd = pmd_offset(pud, addr); 6403dc14741SHugh Dickins struct address_space *mapping; 6413dc14741SHugh Dickins pgoff_t index; 642d936cf9bSHugh Dickins static unsigned long resume; 643d936cf9bSHugh Dickins static unsigned long nr_shown; 644d936cf9bSHugh Dickins static unsigned long nr_unshown; 645d936cf9bSHugh Dickins 646d936cf9bSHugh Dickins /* 647d936cf9bSHugh Dickins * Allow a burst of 60 reports, then keep quiet for that minute; 648d936cf9bSHugh Dickins * or allow a steady drip of one report per second. 649d936cf9bSHugh Dickins */ 650d936cf9bSHugh Dickins if (nr_shown == 60) { 651d936cf9bSHugh Dickins if (time_before(jiffies, resume)) { 652d936cf9bSHugh Dickins nr_unshown++; 653d936cf9bSHugh Dickins return; 654d936cf9bSHugh Dickins } 655d936cf9bSHugh Dickins if (nr_unshown) { 6561e9e6365SHugh Dickins printk(KERN_ALERT 6571e9e6365SHugh Dickins "BUG: Bad page map: %lu messages suppressed\n", 658d936cf9bSHugh Dickins nr_unshown); 659d936cf9bSHugh Dickins nr_unshown = 0; 660d936cf9bSHugh Dickins } 661d936cf9bSHugh Dickins nr_shown = 0; 662d936cf9bSHugh Dickins } 663d936cf9bSHugh Dickins if (nr_shown++ == 0) 664d936cf9bSHugh Dickins resume = jiffies + 60 * HZ; 6653dc14741SHugh Dickins 6663dc14741SHugh Dickins mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; 6673dc14741SHugh Dickins index = linear_page_index(vma, addr); 6683dc14741SHugh Dickins 6691e9e6365SHugh Dickins printk(KERN_ALERT 6701e9e6365SHugh Dickins "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", 6713dc14741SHugh Dickins current->comm, 6723dc14741SHugh Dickins (long long)pte_val(pte), (long long)pmd_val(*pmd)); 673718a3821SWu Fengguang if (page) 674718a3821SWu Fengguang dump_page(page); 6751e9e6365SHugh Dickins printk(KERN_ALERT 6763dc14741SHugh Dickins "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", 6773dc14741SHugh Dickins (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); 6783dc14741SHugh Dickins /* 6793dc14741SHugh Dickins * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y 6803dc14741SHugh Dickins */ 6813dc14741SHugh Dickins if (vma->vm_ops) 682071361d3SJoe Perches printk(KERN_ALERT "vma->vm_ops->fault: %pSR\n", 683071361d3SJoe Perches vma->vm_ops->fault); 6843dc14741SHugh Dickins if (vma->vm_file && vma->vm_file->f_op) 685071361d3SJoe Perches printk(KERN_ALERT "vma->vm_file->f_op->mmap: %pSR\n", 686071361d3SJoe Perches vma->vm_file->f_op->mmap); 687b5810039SNick Piggin dump_stack(); 688373d4d09SRusty Russell add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 689b5810039SNick Piggin } 690b5810039SNick Piggin 6912ec74c3eSSagi Grimberg static inline bool is_cow_mapping(vm_flags_t flags) 69267121172SLinus Torvalds { 69367121172SLinus Torvalds return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 69467121172SLinus Torvalds } 69567121172SLinus Torvalds 696b5810039SNick Piggin /* 6977e675137SNick Piggin * vm_normal_page -- This function gets the "struct page" associated with a pte. 6986aab341eSLinus Torvalds * 6997e675137SNick Piggin * "Special" mappings do not wish to be associated with a "struct page" (either 7007e675137SNick Piggin * it doesn't exist, or it exists but they don't want to touch it). In this 7017e675137SNick Piggin * case, NULL is returned here. "Normal" mappings do have a struct page. 702b379d790SJared Hulbert * 7037e675137SNick Piggin * There are 2 broad cases. Firstly, an architecture may define a pte_special() 7047e675137SNick Piggin * pte bit, in which case this function is trivial. Secondly, an architecture 7057e675137SNick Piggin * may not have a spare pte bit, which requires a more complicated scheme, 7067e675137SNick Piggin * described below. 7077e675137SNick Piggin * 7087e675137SNick Piggin * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a 7097e675137SNick Piggin * special mapping (even if there are underlying and valid "struct pages"). 7107e675137SNick Piggin * COWed pages of a VM_PFNMAP are always normal. 7116aab341eSLinus Torvalds * 712b379d790SJared Hulbert * The way we recognize COWed pages within VM_PFNMAP mappings is through the 713b379d790SJared Hulbert * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit 7147e675137SNick Piggin * set, and the vm_pgoff will point to the first PFN mapped: thus every special 7157e675137SNick Piggin * mapping will always honor the rule 7166aab341eSLinus Torvalds * 7176aab341eSLinus Torvalds * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 7186aab341eSLinus Torvalds * 7197e675137SNick Piggin * And for normal mappings this is false. 720b379d790SJared Hulbert * 7217e675137SNick Piggin * This restricts such mappings to be a linear translation from virtual address 7227e675137SNick Piggin * to pfn. To get around this restriction, we allow arbitrary mappings so long 7237e675137SNick Piggin * as the vma is not a COW mapping; in that case, we know that all ptes are 7247e675137SNick Piggin * special (because none can have been COWed). 725b379d790SJared Hulbert * 726b379d790SJared Hulbert * 7277e675137SNick Piggin * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. 7287e675137SNick Piggin * 729b379d790SJared Hulbert * VM_MIXEDMAP mappings can likewise contain memory with or without "struct 730b379d790SJared Hulbert * page" backing, however the difference is that _all_ pages with a struct 731b379d790SJared Hulbert * page (that is, those where pfn_valid is true) are refcounted and considered 732b379d790SJared Hulbert * normal pages by the VM. The disadvantage is that pages are refcounted 733b379d790SJared Hulbert * (which can be slower and simply not an option for some PFNMAP users). The 734b379d790SJared Hulbert * advantage is that we don't have to follow the strict linearity rule of 735b379d790SJared Hulbert * PFNMAP mappings in order to support COWable mappings. 736b379d790SJared Hulbert * 737ee498ed7SHugh Dickins */ 7387e675137SNick Piggin #ifdef __HAVE_ARCH_PTE_SPECIAL 7397e675137SNick Piggin # define HAVE_PTE_SPECIAL 1 7407e675137SNick Piggin #else 7417e675137SNick Piggin # define HAVE_PTE_SPECIAL 0 7427e675137SNick Piggin #endif 7437e675137SNick Piggin struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 7447e675137SNick Piggin pte_t pte) 745ee498ed7SHugh Dickins { 74622b31eecSHugh Dickins unsigned long pfn = pte_pfn(pte); 7477e675137SNick Piggin 7487e675137SNick Piggin if (HAVE_PTE_SPECIAL) { 74922b31eecSHugh Dickins if (likely(!pte_special(pte))) 75022b31eecSHugh Dickins goto check_pfn; 751a13ea5b7SHugh Dickins if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) 752a13ea5b7SHugh Dickins return NULL; 75362eede62SHugh Dickins if (!is_zero_pfn(pfn)) 75422b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 7557e675137SNick Piggin return NULL; 7567e675137SNick Piggin } 7577e675137SNick Piggin 7587e675137SNick Piggin /* !HAVE_PTE_SPECIAL case follows: */ 7597e675137SNick Piggin 760b379d790SJared Hulbert if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { 761b379d790SJared Hulbert if (vma->vm_flags & VM_MIXEDMAP) { 762b379d790SJared Hulbert if (!pfn_valid(pfn)) 763b379d790SJared Hulbert return NULL; 764b379d790SJared Hulbert goto out; 765b379d790SJared Hulbert } else { 7667e675137SNick Piggin unsigned long off; 7677e675137SNick Piggin off = (addr - vma->vm_start) >> PAGE_SHIFT; 7686aab341eSLinus Torvalds if (pfn == vma->vm_pgoff + off) 7696aab341eSLinus Torvalds return NULL; 77067121172SLinus Torvalds if (!is_cow_mapping(vma->vm_flags)) 771fb155c16SLinus Torvalds return NULL; 7726aab341eSLinus Torvalds } 773b379d790SJared Hulbert } 7746aab341eSLinus Torvalds 77562eede62SHugh Dickins if (is_zero_pfn(pfn)) 77662eede62SHugh Dickins return NULL; 77722b31eecSHugh Dickins check_pfn: 77822b31eecSHugh Dickins if (unlikely(pfn > highest_memmap_pfn)) { 77922b31eecSHugh Dickins print_bad_pte(vma, addr, pte, NULL); 78022b31eecSHugh Dickins return NULL; 78122b31eecSHugh Dickins } 7826aab341eSLinus Torvalds 7836aab341eSLinus Torvalds /* 7847e675137SNick Piggin * NOTE! We still have PageReserved() pages in the page tables. 7857e675137SNick Piggin * eg. VDSO mappings can cause them to exist. 7866aab341eSLinus Torvalds */ 787b379d790SJared Hulbert out: 7886aab341eSLinus Torvalds return pfn_to_page(pfn); 789ee498ed7SHugh Dickins } 790ee498ed7SHugh Dickins 791ee498ed7SHugh Dickins /* 7921da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 7931da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 7941da177e4SLinus Torvalds * covered by this vma. 7951da177e4SLinus Torvalds */ 7961da177e4SLinus Torvalds 797570a335bSHugh Dickins static inline unsigned long 7981da177e4SLinus Torvalds copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 799b5810039SNick Piggin pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 8008c103762SHugh Dickins unsigned long addr, int *rss) 8011da177e4SLinus Torvalds { 802b5810039SNick Piggin unsigned long vm_flags = vma->vm_flags; 8031da177e4SLinus Torvalds pte_t pte = *src_pte; 8041da177e4SLinus Torvalds struct page *page; 8051da177e4SLinus Torvalds 8061da177e4SLinus Torvalds /* pte contains position in swap or file, so copy. */ 8071da177e4SLinus Torvalds if (unlikely(!pte_present(pte))) { 8081da177e4SLinus Torvalds if (!pte_file(pte)) { 8090697212aSChristoph Lameter swp_entry_t entry = pte_to_swp_entry(pte); 8100697212aSChristoph Lameter 811570a335bSHugh Dickins if (swap_duplicate(entry) < 0) 812570a335bSHugh Dickins return entry.val; 813570a335bSHugh Dickins 8141da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 8151da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 8161da177e4SLinus Torvalds spin_lock(&mmlist_lock); 817f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 818f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 819f412ac08SHugh Dickins &src_mm->mmlist); 8201da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 8211da177e4SLinus Torvalds } 822b084d435SKAMEZAWA Hiroyuki if (likely(!non_swap_entry(entry))) 823b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]++; 8249f9f1acdSKonstantin Khlebnikov else if (is_migration_entry(entry)) { 8259f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 8269f9f1acdSKonstantin Khlebnikov 8279f9f1acdSKonstantin Khlebnikov if (PageAnon(page)) 8289f9f1acdSKonstantin Khlebnikov rss[MM_ANONPAGES]++; 8299f9f1acdSKonstantin Khlebnikov else 8309f9f1acdSKonstantin Khlebnikov rss[MM_FILEPAGES]++; 8319f9f1acdSKonstantin Khlebnikov 8329f9f1acdSKonstantin Khlebnikov if (is_write_migration_entry(entry) && 8330697212aSChristoph Lameter is_cow_mapping(vm_flags)) { 8340697212aSChristoph Lameter /* 8359f9f1acdSKonstantin Khlebnikov * COW mappings require pages in both 8369f9f1acdSKonstantin Khlebnikov * parent and child to be set to read. 8370697212aSChristoph Lameter */ 8380697212aSChristoph Lameter make_migration_entry_read(&entry); 8390697212aSChristoph Lameter pte = swp_entry_to_pte(entry); 8400697212aSChristoph Lameter set_pte_at(src_mm, addr, src_pte, pte); 8410697212aSChristoph Lameter } 8421da177e4SLinus Torvalds } 8439f9f1acdSKonstantin Khlebnikov } 844ae859762SHugh Dickins goto out_set_pte; 8451da177e4SLinus Torvalds } 8461da177e4SLinus Torvalds 8471da177e4SLinus Torvalds /* 8481da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 8491da177e4SLinus Torvalds * in the parent and the child 8501da177e4SLinus Torvalds */ 85167121172SLinus Torvalds if (is_cow_mapping(vm_flags)) { 8521da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 8533dc90795SZachary Amsden pte = pte_wrprotect(pte); 8541da177e4SLinus Torvalds } 8551da177e4SLinus Torvalds 8561da177e4SLinus Torvalds /* 8571da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 8581da177e4SLinus Torvalds * the child 8591da177e4SLinus Torvalds */ 8601da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 8611da177e4SLinus Torvalds pte = pte_mkclean(pte); 8621da177e4SLinus Torvalds pte = pte_mkold(pte); 8636aab341eSLinus Torvalds 8646aab341eSLinus Torvalds page = vm_normal_page(vma, addr, pte); 8656aab341eSLinus Torvalds if (page) { 8661da177e4SLinus Torvalds get_page(page); 86721333b2bSHugh Dickins page_dup_rmap(page); 868d559db08SKAMEZAWA Hiroyuki if (PageAnon(page)) 869d559db08SKAMEZAWA Hiroyuki rss[MM_ANONPAGES]++; 870d559db08SKAMEZAWA Hiroyuki else 871d559db08SKAMEZAWA Hiroyuki rss[MM_FILEPAGES]++; 8726aab341eSLinus Torvalds } 873ae859762SHugh Dickins 874ae859762SHugh Dickins out_set_pte: 875ae859762SHugh Dickins set_pte_at(dst_mm, addr, dst_pte, pte); 876570a335bSHugh Dickins return 0; 8771da177e4SLinus Torvalds } 8781da177e4SLinus Torvalds 87971e3aac0SAndrea Arcangeli int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 8801da177e4SLinus Torvalds pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 8811da177e4SLinus Torvalds unsigned long addr, unsigned long end) 8821da177e4SLinus Torvalds { 883c36987e2SDaisuke Nishimura pte_t *orig_src_pte, *orig_dst_pte; 8841da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 885c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 886e040f218SHugh Dickins int progress = 0; 887d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 888570a335bSHugh Dickins swp_entry_t entry = (swp_entry_t){0}; 8891da177e4SLinus Torvalds 8901da177e4SLinus Torvalds again: 891d559db08SKAMEZAWA Hiroyuki init_rss_vec(rss); 892d559db08SKAMEZAWA Hiroyuki 893c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 8941da177e4SLinus Torvalds if (!dst_pte) 8951da177e4SLinus Torvalds return -ENOMEM; 896ece0e2b6SPeter Zijlstra src_pte = pte_offset_map(src_pmd, addr); 8974c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 898f20dc5f7SIngo Molnar spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 899c36987e2SDaisuke Nishimura orig_src_pte = src_pte; 900c36987e2SDaisuke Nishimura orig_dst_pte = dst_pte; 9016606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 9021da177e4SLinus Torvalds 9031da177e4SLinus Torvalds do { 9041da177e4SLinus Torvalds /* 9051da177e4SLinus Torvalds * We are holding two locks at this point - either of them 9061da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 9071da177e4SLinus Torvalds */ 908e040f218SHugh Dickins if (progress >= 32) { 909e040f218SHugh Dickins progress = 0; 910e040f218SHugh Dickins if (need_resched() || 91195c354feSNick Piggin spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 9121da177e4SLinus Torvalds break; 913e040f218SHugh Dickins } 9141da177e4SLinus Torvalds if (pte_none(*src_pte)) { 9151da177e4SLinus Torvalds progress++; 9161da177e4SLinus Torvalds continue; 9171da177e4SLinus Torvalds } 918570a335bSHugh Dickins entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, 919570a335bSHugh Dickins vma, addr, rss); 920570a335bSHugh Dickins if (entry.val) 921570a335bSHugh Dickins break; 9221da177e4SLinus Torvalds progress += 8; 9231da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 9241da177e4SLinus Torvalds 9256606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 926c74df32cSHugh Dickins spin_unlock(src_ptl); 927ece0e2b6SPeter Zijlstra pte_unmap(orig_src_pte); 928d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(dst_mm, rss); 929c36987e2SDaisuke Nishimura pte_unmap_unlock(orig_dst_pte, dst_ptl); 930c74df32cSHugh Dickins cond_resched(); 931570a335bSHugh Dickins 932570a335bSHugh Dickins if (entry.val) { 933570a335bSHugh Dickins if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) 934570a335bSHugh Dickins return -ENOMEM; 935570a335bSHugh Dickins progress = 0; 936570a335bSHugh Dickins } 9371da177e4SLinus Torvalds if (addr != end) 9381da177e4SLinus Torvalds goto again; 9391da177e4SLinus Torvalds return 0; 9401da177e4SLinus Torvalds } 9411da177e4SLinus Torvalds 9421da177e4SLinus Torvalds static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 9431da177e4SLinus Torvalds pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 9441da177e4SLinus Torvalds unsigned long addr, unsigned long end) 9451da177e4SLinus Torvalds { 9461da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 9471da177e4SLinus Torvalds unsigned long next; 9481da177e4SLinus Torvalds 9491da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 9501da177e4SLinus Torvalds if (!dst_pmd) 9511da177e4SLinus Torvalds return -ENOMEM; 9521da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 9531da177e4SLinus Torvalds do { 9541da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 95571e3aac0SAndrea Arcangeli if (pmd_trans_huge(*src_pmd)) { 95671e3aac0SAndrea Arcangeli int err; 95714d1a55cSAndrea Arcangeli VM_BUG_ON(next-addr != HPAGE_PMD_SIZE); 95871e3aac0SAndrea Arcangeli err = copy_huge_pmd(dst_mm, src_mm, 95971e3aac0SAndrea Arcangeli dst_pmd, src_pmd, addr, vma); 96071e3aac0SAndrea Arcangeli if (err == -ENOMEM) 96171e3aac0SAndrea Arcangeli return -ENOMEM; 96271e3aac0SAndrea Arcangeli if (!err) 96371e3aac0SAndrea Arcangeli continue; 96471e3aac0SAndrea Arcangeli /* fall through */ 96571e3aac0SAndrea Arcangeli } 9661da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 9671da177e4SLinus Torvalds continue; 9681da177e4SLinus Torvalds if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 9691da177e4SLinus Torvalds vma, addr, next)) 9701da177e4SLinus Torvalds return -ENOMEM; 9711da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 9721da177e4SLinus Torvalds return 0; 9731da177e4SLinus Torvalds } 9741da177e4SLinus Torvalds 9751da177e4SLinus Torvalds static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 9761da177e4SLinus Torvalds pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 9771da177e4SLinus Torvalds unsigned long addr, unsigned long end) 9781da177e4SLinus Torvalds { 9791da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 9801da177e4SLinus Torvalds unsigned long next; 9811da177e4SLinus Torvalds 9821da177e4SLinus Torvalds dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 9831da177e4SLinus Torvalds if (!dst_pud) 9841da177e4SLinus Torvalds return -ENOMEM; 9851da177e4SLinus Torvalds src_pud = pud_offset(src_pgd, addr); 9861da177e4SLinus Torvalds do { 9871da177e4SLinus Torvalds next = pud_addr_end(addr, end); 9881da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 9891da177e4SLinus Torvalds continue; 9901da177e4SLinus Torvalds if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 9911da177e4SLinus Torvalds vma, addr, next)) 9921da177e4SLinus Torvalds return -ENOMEM; 9931da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 9941da177e4SLinus Torvalds return 0; 9951da177e4SLinus Torvalds } 9961da177e4SLinus Torvalds 9971da177e4SLinus Torvalds int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 9981da177e4SLinus Torvalds struct vm_area_struct *vma) 9991da177e4SLinus Torvalds { 10001da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 10011da177e4SLinus Torvalds unsigned long next; 10021da177e4SLinus Torvalds unsigned long addr = vma->vm_start; 10031da177e4SLinus Torvalds unsigned long end = vma->vm_end; 10042ec74c3eSSagi Grimberg unsigned long mmun_start; /* For mmu_notifiers */ 10052ec74c3eSSagi Grimberg unsigned long mmun_end; /* For mmu_notifiers */ 10062ec74c3eSSagi Grimberg bool is_cow; 1007cddb8a5cSAndrea Arcangeli int ret; 10081da177e4SLinus Torvalds 1009d992895bSNick Piggin /* 1010d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 1011d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 1012d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 1013d992895bSNick Piggin * efficient than faulting. 1014d992895bSNick Piggin */ 10154b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR | 10164b6e1e37SKonstantin Khlebnikov VM_PFNMAP | VM_MIXEDMAP))) { 1017d992895bSNick Piggin if (!vma->anon_vma) 1018d992895bSNick Piggin return 0; 1019d992895bSNick Piggin } 1020d992895bSNick Piggin 10211da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) 10221da177e4SLinus Torvalds return copy_hugetlb_page_range(dst_mm, src_mm, vma); 10231da177e4SLinus Torvalds 1024b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) { 10252ab64037Svenkatesh.pallipadi@intel.com /* 10262ab64037Svenkatesh.pallipadi@intel.com * We do not free on error cases below as remove_vma 10272ab64037Svenkatesh.pallipadi@intel.com * gets called on error from higher level routine 10282ab64037Svenkatesh.pallipadi@intel.com */ 10295180da41SSuresh Siddha ret = track_pfn_copy(vma); 10302ab64037Svenkatesh.pallipadi@intel.com if (ret) 10312ab64037Svenkatesh.pallipadi@intel.com return ret; 10322ab64037Svenkatesh.pallipadi@intel.com } 10332ab64037Svenkatesh.pallipadi@intel.com 1034cddb8a5cSAndrea Arcangeli /* 1035cddb8a5cSAndrea Arcangeli * We need to invalidate the secondary MMU mappings only when 1036cddb8a5cSAndrea Arcangeli * there could be a permission downgrade on the ptes of the 1037cddb8a5cSAndrea Arcangeli * parent mm. And a permission downgrade will only happen if 1038cddb8a5cSAndrea Arcangeli * is_cow_mapping() returns true. 1039cddb8a5cSAndrea Arcangeli */ 10402ec74c3eSSagi Grimberg is_cow = is_cow_mapping(vma->vm_flags); 10412ec74c3eSSagi Grimberg mmun_start = addr; 10422ec74c3eSSagi Grimberg mmun_end = end; 10432ec74c3eSSagi Grimberg if (is_cow) 10442ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_start(src_mm, mmun_start, 10452ec74c3eSSagi Grimberg mmun_end); 1046cddb8a5cSAndrea Arcangeli 1047cddb8a5cSAndrea Arcangeli ret = 0; 10481da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 10491da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 10501da177e4SLinus Torvalds do { 10511da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 10521da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 10531da177e4SLinus Torvalds continue; 1054cddb8a5cSAndrea Arcangeli if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 1055cddb8a5cSAndrea Arcangeli vma, addr, next))) { 1056cddb8a5cSAndrea Arcangeli ret = -ENOMEM; 1057cddb8a5cSAndrea Arcangeli break; 1058cddb8a5cSAndrea Arcangeli } 10591da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 1060cddb8a5cSAndrea Arcangeli 10612ec74c3eSSagi Grimberg if (is_cow) 10622ec74c3eSSagi Grimberg mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end); 1063cddb8a5cSAndrea Arcangeli return ret; 10641da177e4SLinus Torvalds } 10651da177e4SLinus Torvalds 106651c6f666SRobin Holt static unsigned long zap_pte_range(struct mmu_gather *tlb, 1067b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 10681da177e4SLinus Torvalds unsigned long addr, unsigned long end, 106997a89413SPeter Zijlstra struct zap_details *details) 10701da177e4SLinus Torvalds { 1071b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 1072d16dfc55SPeter Zijlstra int force_flush = 0; 1073d559db08SKAMEZAWA Hiroyuki int rss[NR_MM_COUNTERS]; 107497a89413SPeter Zijlstra spinlock_t *ptl; 10755f1a1907SSteven Rostedt pte_t *start_pte; 107697a89413SPeter Zijlstra pte_t *pte; 1077d559db08SKAMEZAWA Hiroyuki 1078d16dfc55SPeter Zijlstra again: 1079e303297eSPeter Zijlstra init_rss_vec(rss); 10805f1a1907SSteven Rostedt start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 10815f1a1907SSteven Rostedt pte = start_pte; 10826606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 10831da177e4SLinus Torvalds do { 10841da177e4SLinus Torvalds pte_t ptent = *pte; 108551c6f666SRobin Holt if (pte_none(ptent)) { 10861da177e4SLinus Torvalds continue; 108751c6f666SRobin Holt } 108851c6f666SRobin Holt 10896f5e6b9eSHugh Dickins if (pte_present(ptent)) { 10906f5e6b9eSHugh Dickins struct page *page; 10916f5e6b9eSHugh Dickins 10926aab341eSLinus Torvalds page = vm_normal_page(vma, addr, ptent); 10931da177e4SLinus Torvalds if (unlikely(details) && page) { 10941da177e4SLinus Torvalds /* 10951da177e4SLinus Torvalds * unmap_shared_mapping_pages() wants to 10961da177e4SLinus Torvalds * invalidate cache without truncating: 10971da177e4SLinus Torvalds * unmap shared but keep private pages. 10981da177e4SLinus Torvalds */ 10991da177e4SLinus Torvalds if (details->check_mapping && 11001da177e4SLinus Torvalds details->check_mapping != page->mapping) 11011da177e4SLinus Torvalds continue; 11021da177e4SLinus Torvalds /* 11031da177e4SLinus Torvalds * Each page->index must be checked when 11041da177e4SLinus Torvalds * invalidating or truncating nonlinear. 11051da177e4SLinus Torvalds */ 11061da177e4SLinus Torvalds if (details->nonlinear_vma && 11071da177e4SLinus Torvalds (page->index < details->first_index || 11081da177e4SLinus Torvalds page->index > details->last_index)) 11091da177e4SLinus Torvalds continue; 11101da177e4SLinus Torvalds } 1111b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 1112a600388dSZachary Amsden tlb->fullmm); 11131da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 11141da177e4SLinus Torvalds if (unlikely(!page)) 11151da177e4SLinus Torvalds continue; 11161da177e4SLinus Torvalds if (unlikely(details) && details->nonlinear_vma 11171da177e4SLinus Torvalds && linear_page_index(details->nonlinear_vma, 111841bb3476SCyrill Gorcunov addr) != page->index) { 111941bb3476SCyrill Gorcunov pte_t ptfile = pgoff_to_pte(page->index); 112041bb3476SCyrill Gorcunov if (pte_soft_dirty(ptent)) 112141bb3476SCyrill Gorcunov pte_file_mksoft_dirty(ptfile); 112241bb3476SCyrill Gorcunov set_pte_at(mm, addr, pte, ptfile); 112341bb3476SCyrill Gorcunov } 11241da177e4SLinus Torvalds if (PageAnon(page)) 1125d559db08SKAMEZAWA Hiroyuki rss[MM_ANONPAGES]--; 11266237bcd9SHugh Dickins else { 11276237bcd9SHugh Dickins if (pte_dirty(ptent)) 11286237bcd9SHugh Dickins set_page_dirty(page); 11294917e5d0SJohannes Weiner if (pte_young(ptent) && 113064363aadSJoe Perches likely(!(vma->vm_flags & VM_SEQ_READ))) 1131bf3f3bc5SNick Piggin mark_page_accessed(page); 1132d559db08SKAMEZAWA Hiroyuki rss[MM_FILEPAGES]--; 11336237bcd9SHugh Dickins } 1134edc315fdSHugh Dickins page_remove_rmap(page); 11353dc14741SHugh Dickins if (unlikely(page_mapcount(page) < 0)) 11363dc14741SHugh Dickins print_bad_pte(vma, addr, ptent, page); 1137d16dfc55SPeter Zijlstra force_flush = !__tlb_remove_page(tlb, page); 1138d16dfc55SPeter Zijlstra if (force_flush) 1139d16dfc55SPeter Zijlstra break; 11401da177e4SLinus Torvalds continue; 11411da177e4SLinus Torvalds } 11421da177e4SLinus Torvalds /* 11431da177e4SLinus Torvalds * If details->check_mapping, we leave swap entries; 11441da177e4SLinus Torvalds * if details->nonlinear_vma, we leave file entries. 11451da177e4SLinus Torvalds */ 11461da177e4SLinus Torvalds if (unlikely(details)) 11471da177e4SLinus Torvalds continue; 11482509ef26SHugh Dickins if (pte_file(ptent)) { 11492509ef26SHugh Dickins if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) 11502509ef26SHugh Dickins print_bad_pte(vma, addr, ptent, NULL); 1151b084d435SKAMEZAWA Hiroyuki } else { 1152b084d435SKAMEZAWA Hiroyuki swp_entry_t entry = pte_to_swp_entry(ptent); 1153b084d435SKAMEZAWA Hiroyuki 1154b084d435SKAMEZAWA Hiroyuki if (!non_swap_entry(entry)) 1155b084d435SKAMEZAWA Hiroyuki rss[MM_SWAPENTS]--; 11569f9f1acdSKonstantin Khlebnikov else if (is_migration_entry(entry)) { 11579f9f1acdSKonstantin Khlebnikov struct page *page; 11589f9f1acdSKonstantin Khlebnikov 11599f9f1acdSKonstantin Khlebnikov page = migration_entry_to_page(entry); 11609f9f1acdSKonstantin Khlebnikov 11619f9f1acdSKonstantin Khlebnikov if (PageAnon(page)) 11629f9f1acdSKonstantin Khlebnikov rss[MM_ANONPAGES]--; 11639f9f1acdSKonstantin Khlebnikov else 11649f9f1acdSKonstantin Khlebnikov rss[MM_FILEPAGES]--; 11659f9f1acdSKonstantin Khlebnikov } 1166b084d435SKAMEZAWA Hiroyuki if (unlikely(!free_swap_and_cache(entry))) 11672509ef26SHugh Dickins print_bad_pte(vma, addr, ptent, NULL); 1168b084d435SKAMEZAWA Hiroyuki } 11699888a1caSZachary Amsden pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 117097a89413SPeter Zijlstra } while (pte++, addr += PAGE_SIZE, addr != end); 1171ae859762SHugh Dickins 1172d559db08SKAMEZAWA Hiroyuki add_mm_rss_vec(mm, rss); 11736606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 11745f1a1907SSteven Rostedt pte_unmap_unlock(start_pte, ptl); 117551c6f666SRobin Holt 1176d16dfc55SPeter Zijlstra /* 1177d16dfc55SPeter Zijlstra * mmu_gather ran out of room to batch pages, we break out of 1178d16dfc55SPeter Zijlstra * the PTE lock to avoid doing the potential expensive TLB invalidate 1179d16dfc55SPeter Zijlstra * and page-free while holding it. 1180d16dfc55SPeter Zijlstra */ 1181d16dfc55SPeter Zijlstra if (force_flush) { 11822b047252SLinus Torvalds unsigned long old_end; 11832b047252SLinus Torvalds 1184d16dfc55SPeter Zijlstra force_flush = 0; 1185597e1c35SAlex Shi 11862b047252SLinus Torvalds /* 11872b047252SLinus Torvalds * Flush the TLB just for the previous segment, 11882b047252SLinus Torvalds * then update the range to be the remaining 11892b047252SLinus Torvalds * TLB range. 11902b047252SLinus Torvalds */ 11912b047252SLinus Torvalds old_end = tlb->end; 1192e6c495a9SVineet Gupta tlb->end = addr; 11932b047252SLinus Torvalds 1194d16dfc55SPeter Zijlstra tlb_flush_mmu(tlb); 11952b047252SLinus Torvalds 11962b047252SLinus Torvalds tlb->start = addr; 11972b047252SLinus Torvalds tlb->end = old_end; 11982b047252SLinus Torvalds 11992b047252SLinus Torvalds if (addr != end) 1200d16dfc55SPeter Zijlstra goto again; 1201d16dfc55SPeter Zijlstra } 1202d16dfc55SPeter Zijlstra 120351c6f666SRobin Holt return addr; 12041da177e4SLinus Torvalds } 12051da177e4SLinus Torvalds 120651c6f666SRobin Holt static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 1207b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 12081da177e4SLinus Torvalds unsigned long addr, unsigned long end, 120997a89413SPeter Zijlstra struct zap_details *details) 12101da177e4SLinus Torvalds { 12111da177e4SLinus Torvalds pmd_t *pmd; 12121da177e4SLinus Torvalds unsigned long next; 12131da177e4SLinus Torvalds 12141da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 12151da177e4SLinus Torvalds do { 12161da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 121771e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 121814d1a55cSAndrea Arcangeli if (next - addr != HPAGE_PMD_SIZE) { 1219e0897d75SDavid Rientjes #ifdef CONFIG_DEBUG_VM 1220e0897d75SDavid Rientjes if (!rwsem_is_locked(&tlb->mm->mmap_sem)) { 1221e0897d75SDavid Rientjes pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n", 1222e0897d75SDavid Rientjes __func__, addr, end, 1223e0897d75SDavid Rientjes vma->vm_start, 1224e0897d75SDavid Rientjes vma->vm_end); 1225e0897d75SDavid Rientjes BUG(); 1226e0897d75SDavid Rientjes } 1227e0897d75SDavid Rientjes #endif 1228e180377fSKirill A. Shutemov split_huge_page_pmd(vma, addr, pmd); 1229f21760b1SShaohua Li } else if (zap_huge_pmd(tlb, vma, pmd, addr)) 12301a5a9906SAndrea Arcangeli goto next; 123171e3aac0SAndrea Arcangeli /* fall through */ 123271e3aac0SAndrea Arcangeli } 12331a5a9906SAndrea Arcangeli /* 12341a5a9906SAndrea Arcangeli * Here there can be other concurrent MADV_DONTNEED or 12351a5a9906SAndrea Arcangeli * trans huge page faults running, and if the pmd is 12361a5a9906SAndrea Arcangeli * none or trans huge it can change under us. This is 12371a5a9906SAndrea Arcangeli * because MADV_DONTNEED holds the mmap_sem in read 12381a5a9906SAndrea Arcangeli * mode. 12391a5a9906SAndrea Arcangeli */ 12401a5a9906SAndrea Arcangeli if (pmd_none_or_trans_huge_or_clear_bad(pmd)) 12411a5a9906SAndrea Arcangeli goto next; 124297a89413SPeter Zijlstra next = zap_pte_range(tlb, vma, pmd, addr, next, details); 12431a5a9906SAndrea Arcangeli next: 124497a89413SPeter Zijlstra cond_resched(); 124597a89413SPeter Zijlstra } while (pmd++, addr = next, addr != end); 124651c6f666SRobin Holt 124751c6f666SRobin Holt return addr; 12481da177e4SLinus Torvalds } 12491da177e4SLinus Torvalds 125051c6f666SRobin Holt static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 1251b5810039SNick Piggin struct vm_area_struct *vma, pgd_t *pgd, 12521da177e4SLinus Torvalds unsigned long addr, unsigned long end, 125397a89413SPeter Zijlstra struct zap_details *details) 12541da177e4SLinus Torvalds { 12551da177e4SLinus Torvalds pud_t *pud; 12561da177e4SLinus Torvalds unsigned long next; 12571da177e4SLinus Torvalds 12581da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 12591da177e4SLinus Torvalds do { 12601da177e4SLinus Torvalds next = pud_addr_end(addr, end); 126197a89413SPeter Zijlstra if (pud_none_or_clear_bad(pud)) 12621da177e4SLinus Torvalds continue; 126397a89413SPeter Zijlstra next = zap_pmd_range(tlb, vma, pud, addr, next, details); 126497a89413SPeter Zijlstra } while (pud++, addr = next, addr != end); 126551c6f666SRobin Holt 126651c6f666SRobin Holt return addr; 12671da177e4SLinus Torvalds } 12681da177e4SLinus Torvalds 1269038c7aa1SAl Viro static void unmap_page_range(struct mmu_gather *tlb, 127051c6f666SRobin Holt struct vm_area_struct *vma, 12711da177e4SLinus Torvalds unsigned long addr, unsigned long end, 127297a89413SPeter Zijlstra struct zap_details *details) 12731da177e4SLinus Torvalds { 12741da177e4SLinus Torvalds pgd_t *pgd; 12751da177e4SLinus Torvalds unsigned long next; 12761da177e4SLinus Torvalds 12771da177e4SLinus Torvalds if (details && !details->check_mapping && !details->nonlinear_vma) 12781da177e4SLinus Torvalds details = NULL; 12791da177e4SLinus Torvalds 12801da177e4SLinus Torvalds BUG_ON(addr >= end); 1281569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_start(); 12821da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 12831da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 12841da177e4SLinus Torvalds do { 12851da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 128697a89413SPeter Zijlstra if (pgd_none_or_clear_bad(pgd)) 12871da177e4SLinus Torvalds continue; 128897a89413SPeter Zijlstra next = zap_pud_range(tlb, vma, pgd, addr, next, details); 128997a89413SPeter Zijlstra } while (pgd++, addr = next, addr != end); 12901da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 1291569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_end(); 12921da177e4SLinus Torvalds } 12931da177e4SLinus Torvalds 1294f5cc4eefSAl Viro 1295f5cc4eefSAl Viro static void unmap_single_vma(struct mmu_gather *tlb, 12961da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 12974f74d2c8SLinus Torvalds unsigned long end_addr, 12981da177e4SLinus Torvalds struct zap_details *details) 12991da177e4SLinus Torvalds { 1300f5cc4eefSAl Viro unsigned long start = max(vma->vm_start, start_addr); 13011da177e4SLinus Torvalds unsigned long end; 13021da177e4SLinus Torvalds 13031da177e4SLinus Torvalds if (start >= vma->vm_end) 1304f5cc4eefSAl Viro return; 13051da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 13061da177e4SLinus Torvalds if (end <= vma->vm_start) 1307f5cc4eefSAl Viro return; 13081da177e4SLinus Torvalds 1309cbc91f71SSrikar Dronamraju if (vma->vm_file) 1310cbc91f71SSrikar Dronamraju uprobe_munmap(vma, start, end); 1311cbc91f71SSrikar Dronamraju 1312b3b9c293SKonstantin Khlebnikov if (unlikely(vma->vm_flags & VM_PFNMAP)) 13135180da41SSuresh Siddha untrack_pfn(vma, 0, 0); 13142ab64037Svenkatesh.pallipadi@intel.com 13158b2a1238SAl Viro if (start != end) { 131651c6f666SRobin Holt if (unlikely(is_vm_hugetlb_page(vma))) { 1317a137e1ccSAndi Kleen /* 1318a137e1ccSAndi Kleen * It is undesirable to test vma->vm_file as it 1319a137e1ccSAndi Kleen * should be non-null for valid hugetlb area. 1320a137e1ccSAndi Kleen * However, vm_file will be NULL in the error 1321a137e1ccSAndi Kleen * cleanup path of do_mmap_pgoff. When 1322a137e1ccSAndi Kleen * hugetlbfs ->mmap method fails, 1323a137e1ccSAndi Kleen * do_mmap_pgoff() nullifies vma->vm_file 1324a137e1ccSAndi Kleen * before calling this function to clean up. 1325a137e1ccSAndi Kleen * Since no pte has actually been setup, it is 1326a137e1ccSAndi Kleen * safe to do nothing in this case. 1327a137e1ccSAndi Kleen */ 132824669e58SAneesh Kumar K.V if (vma->vm_file) { 132924669e58SAneesh Kumar K.V mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 1330d833352aSMel Gorman __unmap_hugepage_range_final(tlb, vma, start, end, NULL); 133124669e58SAneesh Kumar K.V mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 133224669e58SAneesh Kumar K.V } 133351c6f666SRobin Holt } else 1334038c7aa1SAl Viro unmap_page_range(tlb, vma, start, end, details); 133597a89413SPeter Zijlstra } 133651c6f666SRobin Holt } 13371da177e4SLinus Torvalds 1338f5cc4eefSAl Viro /** 1339f5cc4eefSAl Viro * unmap_vmas - unmap a range of memory covered by a list of vma's 1340f5cc4eefSAl Viro * @tlb: address of the caller's struct mmu_gather 1341f5cc4eefSAl Viro * @vma: the starting vma 1342f5cc4eefSAl Viro * @start_addr: virtual address at which to start unmapping 1343f5cc4eefSAl Viro * @end_addr: virtual address at which to end unmapping 1344f5cc4eefSAl Viro * 1345f5cc4eefSAl Viro * Unmap all pages in the vma list. 1346f5cc4eefSAl Viro * 1347f5cc4eefSAl Viro * Only addresses between `start' and `end' will be unmapped. 1348f5cc4eefSAl Viro * 1349f5cc4eefSAl Viro * The VMA list must be sorted in ascending virtual address order. 1350f5cc4eefSAl Viro * 1351f5cc4eefSAl Viro * unmap_vmas() assumes that the caller will flush the whole unmapped address 1352f5cc4eefSAl Viro * range after unmap_vmas() returns. So the only responsibility here is to 1353f5cc4eefSAl Viro * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 1354f5cc4eefSAl Viro * drops the lock and schedules. 1355f5cc4eefSAl Viro */ 1356f5cc4eefSAl Viro void unmap_vmas(struct mmu_gather *tlb, 1357f5cc4eefSAl Viro struct vm_area_struct *vma, unsigned long start_addr, 13584f74d2c8SLinus Torvalds unsigned long end_addr) 1359f5cc4eefSAl Viro { 1360f5cc4eefSAl Viro struct mm_struct *mm = vma->vm_mm; 1361f5cc4eefSAl Viro 1362f5cc4eefSAl Viro mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); 1363f5cc4eefSAl Viro for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) 13644f74d2c8SLinus Torvalds unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); 1365cddb8a5cSAndrea Arcangeli mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); 13661da177e4SLinus Torvalds } 13671da177e4SLinus Torvalds 13681da177e4SLinus Torvalds /** 13691da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 13701da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 1371eb4546bbSRandy Dunlap * @start: starting address of pages to zap 13721da177e4SLinus Torvalds * @size: number of bytes to zap 13731da177e4SLinus Torvalds * @details: details of nonlinear truncation or shared cache invalidation 1374f5cc4eefSAl Viro * 1375f5cc4eefSAl Viro * Caller must protect the VMA list 13761da177e4SLinus Torvalds */ 13777e027b14SLinus Torvalds void zap_page_range(struct vm_area_struct *vma, unsigned long start, 13781da177e4SLinus Torvalds unsigned long size, struct zap_details *details) 13791da177e4SLinus Torvalds { 13801da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 1381d16dfc55SPeter Zijlstra struct mmu_gather tlb; 13827e027b14SLinus Torvalds unsigned long end = start + size; 13831da177e4SLinus Torvalds 13841da177e4SLinus Torvalds lru_add_drain(); 13852b047252SLinus Torvalds tlb_gather_mmu(&tlb, mm, start, end); 1386365e9c87SHugh Dickins update_hiwater_rss(mm); 13877e027b14SLinus Torvalds mmu_notifier_invalidate_range_start(mm, start, end); 13887e027b14SLinus Torvalds for ( ; vma && vma->vm_start < end; vma = vma->vm_next) 13894f74d2c8SLinus Torvalds unmap_single_vma(&tlb, vma, start, end, details); 13907e027b14SLinus Torvalds mmu_notifier_invalidate_range_end(mm, start, end); 13917e027b14SLinus Torvalds tlb_finish_mmu(&tlb, start, end); 13921da177e4SLinus Torvalds } 13931da177e4SLinus Torvalds 1394c627f9ccSJack Steiner /** 1395f5cc4eefSAl Viro * zap_page_range_single - remove user pages in a given range 1396f5cc4eefSAl Viro * @vma: vm_area_struct holding the applicable pages 1397f5cc4eefSAl Viro * @address: starting address of pages to zap 1398f5cc4eefSAl Viro * @size: number of bytes to zap 1399f5cc4eefSAl Viro * @details: details of nonlinear truncation or shared cache invalidation 1400f5cc4eefSAl Viro * 1401f5cc4eefSAl Viro * The range must fit into one VMA. 1402f5cc4eefSAl Viro */ 1403f5cc4eefSAl Viro static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, 1404f5cc4eefSAl Viro unsigned long size, struct zap_details *details) 1405f5cc4eefSAl Viro { 1406f5cc4eefSAl Viro struct mm_struct *mm = vma->vm_mm; 1407f5cc4eefSAl Viro struct mmu_gather tlb; 1408f5cc4eefSAl Viro unsigned long end = address + size; 1409f5cc4eefSAl Viro 1410f5cc4eefSAl Viro lru_add_drain(); 14112b047252SLinus Torvalds tlb_gather_mmu(&tlb, mm, address, end); 1412f5cc4eefSAl Viro update_hiwater_rss(mm); 1413f5cc4eefSAl Viro mmu_notifier_invalidate_range_start(mm, address, end); 14144f74d2c8SLinus Torvalds unmap_single_vma(&tlb, vma, address, end, details); 1415f5cc4eefSAl Viro mmu_notifier_invalidate_range_end(mm, address, end); 1416f5cc4eefSAl Viro tlb_finish_mmu(&tlb, address, end); 14171da177e4SLinus Torvalds } 14181da177e4SLinus Torvalds 1419c627f9ccSJack Steiner /** 1420c627f9ccSJack Steiner * zap_vma_ptes - remove ptes mapping the vma 1421c627f9ccSJack Steiner * @vma: vm_area_struct holding ptes to be zapped 1422c627f9ccSJack Steiner * @address: starting address of pages to zap 1423c627f9ccSJack Steiner * @size: number of bytes to zap 1424c627f9ccSJack Steiner * 1425c627f9ccSJack Steiner * This function only unmaps ptes assigned to VM_PFNMAP vmas. 1426c627f9ccSJack Steiner * 1427c627f9ccSJack Steiner * The entire address range must be fully contained within the vma. 1428c627f9ccSJack Steiner * 1429c627f9ccSJack Steiner * Returns 0 if successful. 1430c627f9ccSJack Steiner */ 1431c627f9ccSJack Steiner int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 1432c627f9ccSJack Steiner unsigned long size) 1433c627f9ccSJack Steiner { 1434c627f9ccSJack Steiner if (address < vma->vm_start || address + size > vma->vm_end || 1435c627f9ccSJack Steiner !(vma->vm_flags & VM_PFNMAP)) 1436c627f9ccSJack Steiner return -1; 1437f5cc4eefSAl Viro zap_page_range_single(vma, address, size, NULL); 1438c627f9ccSJack Steiner return 0; 1439c627f9ccSJack Steiner } 1440c627f9ccSJack Steiner EXPORT_SYMBOL_GPL(zap_vma_ptes); 1441c627f9ccSJack Steiner 1442142762bdSJohannes Weiner /** 1443240aadeeSMichel Lespinasse * follow_page_mask - look up a page descriptor from a user-virtual address 1444142762bdSJohannes Weiner * @vma: vm_area_struct mapping @address 1445142762bdSJohannes Weiner * @address: virtual address to look up 1446142762bdSJohannes Weiner * @flags: flags modifying lookup behaviour 1447240aadeeSMichel Lespinasse * @page_mask: on output, *page_mask is set according to the size of the page 1448142762bdSJohannes Weiner * 1449142762bdSJohannes Weiner * @flags can have FOLL_ flags set, defined in <linux/mm.h> 1450142762bdSJohannes Weiner * 1451142762bdSJohannes Weiner * Returns the mapped (struct page *), %NULL if no mapping exists, or 1452142762bdSJohannes Weiner * an error pointer if there is a mapping to something not represented 1453142762bdSJohannes Weiner * by a page descriptor (see also vm_normal_page()). 14541da177e4SLinus Torvalds */ 1455240aadeeSMichel Lespinasse struct page *follow_page_mask(struct vm_area_struct *vma, 1456240aadeeSMichel Lespinasse unsigned long address, unsigned int flags, 1457240aadeeSMichel Lespinasse unsigned int *page_mask) 14581da177e4SLinus Torvalds { 14591da177e4SLinus Torvalds pgd_t *pgd; 14601da177e4SLinus Torvalds pud_t *pud; 14611da177e4SLinus Torvalds pmd_t *pmd; 14621da177e4SLinus Torvalds pte_t *ptep, pte; 1463deceb6cdSHugh Dickins spinlock_t *ptl; 14641da177e4SLinus Torvalds struct page *page; 14656aab341eSLinus Torvalds struct mm_struct *mm = vma->vm_mm; 14661da177e4SLinus Torvalds 1467240aadeeSMichel Lespinasse *page_mask = 0; 1468240aadeeSMichel Lespinasse 1469deceb6cdSHugh Dickins page = follow_huge_addr(mm, address, flags & FOLL_WRITE); 1470deceb6cdSHugh Dickins if (!IS_ERR(page)) { 1471deceb6cdSHugh Dickins BUG_ON(flags & FOLL_GET); 1472deceb6cdSHugh Dickins goto out; 1473deceb6cdSHugh Dickins } 14741da177e4SLinus Torvalds 1475deceb6cdSHugh Dickins page = NULL; 14761da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 14771da177e4SLinus Torvalds if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 1478deceb6cdSHugh Dickins goto no_page_table; 14791da177e4SLinus Torvalds 14801da177e4SLinus Torvalds pud = pud_offset(pgd, address); 1481ceb86879SAndi Kleen if (pud_none(*pud)) 1482ceb86879SAndi Kleen goto no_page_table; 14838a07651eSHugh Dickins if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { 1484e632a938SNaoya Horiguchi if (flags & FOLL_GET) 1485e632a938SNaoya Horiguchi goto out; 1486ceb86879SAndi Kleen page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); 1487ceb86879SAndi Kleen goto out; 1488ceb86879SAndi Kleen } 1489ceb86879SAndi Kleen if (unlikely(pud_bad(*pud))) 1490deceb6cdSHugh Dickins goto no_page_table; 14911da177e4SLinus Torvalds 14921da177e4SLinus Torvalds pmd = pmd_offset(pud, address); 1493aeed5fceSHugh Dickins if (pmd_none(*pmd)) 1494deceb6cdSHugh Dickins goto no_page_table; 149571e3aac0SAndrea Arcangeli if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) { 1496deceb6cdSHugh Dickins page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); 1497e632a938SNaoya Horiguchi if (flags & FOLL_GET) { 1498e632a938SNaoya Horiguchi /* 1499e632a938SNaoya Horiguchi * Refcount on tail pages are not well-defined and 1500e632a938SNaoya Horiguchi * shouldn't be taken. The caller should handle a NULL 1501e632a938SNaoya Horiguchi * return when trying to follow tail pages. 1502e632a938SNaoya Horiguchi */ 1503e632a938SNaoya Horiguchi if (PageHead(page)) 1504e632a938SNaoya Horiguchi get_page(page); 1505e632a938SNaoya Horiguchi else { 1506e632a938SNaoya Horiguchi page = NULL; 1507e632a938SNaoya Horiguchi goto out; 1508e632a938SNaoya Horiguchi } 1509e632a938SNaoya Horiguchi } 1510deceb6cdSHugh Dickins goto out; 1511deceb6cdSHugh Dickins } 15120b9d7052SAndrea Arcangeli if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) 15130b9d7052SAndrea Arcangeli goto no_page_table; 151471e3aac0SAndrea Arcangeli if (pmd_trans_huge(*pmd)) { 1515500d65d4SAndrea Arcangeli if (flags & FOLL_SPLIT) { 1516e180377fSKirill A. Shutemov split_huge_page_pmd(vma, address, pmd); 1517500d65d4SAndrea Arcangeli goto split_fallthrough; 1518500d65d4SAndrea Arcangeli } 151971e3aac0SAndrea Arcangeli spin_lock(&mm->page_table_lock); 152071e3aac0SAndrea Arcangeli if (likely(pmd_trans_huge(*pmd))) { 152171e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_splitting(*pmd))) { 152271e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 152371e3aac0SAndrea Arcangeli wait_split_huge_page(vma->anon_vma, pmd); 152471e3aac0SAndrea Arcangeli } else { 1525b676b293SDavid Rientjes page = follow_trans_huge_pmd(vma, address, 152671e3aac0SAndrea Arcangeli pmd, flags); 152771e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 1528240aadeeSMichel Lespinasse *page_mask = HPAGE_PMD_NR - 1; 152971e3aac0SAndrea Arcangeli goto out; 153071e3aac0SAndrea Arcangeli } 153171e3aac0SAndrea Arcangeli } else 153271e3aac0SAndrea Arcangeli spin_unlock(&mm->page_table_lock); 153371e3aac0SAndrea Arcangeli /* fall through */ 153471e3aac0SAndrea Arcangeli } 1535500d65d4SAndrea Arcangeli split_fallthrough: 1536aeed5fceSHugh Dickins if (unlikely(pmd_bad(*pmd))) 1537aeed5fceSHugh Dickins goto no_page_table; 1538aeed5fceSHugh Dickins 1539deceb6cdSHugh Dickins ptep = pte_offset_map_lock(mm, pmd, address, &ptl); 15401da177e4SLinus Torvalds 15411da177e4SLinus Torvalds pte = *ptep; 15425117b3b8SHugh Dickins if (!pte_present(pte)) { 15435117b3b8SHugh Dickins swp_entry_t entry; 15445117b3b8SHugh Dickins /* 15455117b3b8SHugh Dickins * KSM's break_ksm() relies upon recognizing a ksm page 15465117b3b8SHugh Dickins * even while it is being migrated, so for that case we 15475117b3b8SHugh Dickins * need migration_entry_wait(). 15485117b3b8SHugh Dickins */ 15495117b3b8SHugh Dickins if (likely(!(flags & FOLL_MIGRATION))) 155089f5b7daSLinus Torvalds goto no_page; 15515117b3b8SHugh Dickins if (pte_none(pte) || pte_file(pte)) 15525117b3b8SHugh Dickins goto no_page; 15535117b3b8SHugh Dickins entry = pte_to_swp_entry(pte); 15545117b3b8SHugh Dickins if (!is_migration_entry(entry)) 15555117b3b8SHugh Dickins goto no_page; 15565117b3b8SHugh Dickins pte_unmap_unlock(ptep, ptl); 15575117b3b8SHugh Dickins migration_entry_wait(mm, pmd, address); 15585117b3b8SHugh Dickins goto split_fallthrough; 15595117b3b8SHugh Dickins } 15600b9d7052SAndrea Arcangeli if ((flags & FOLL_NUMA) && pte_numa(pte)) 15610b9d7052SAndrea Arcangeli goto no_page; 1562deceb6cdSHugh Dickins if ((flags & FOLL_WRITE) && !pte_write(pte)) 1563deceb6cdSHugh Dickins goto unlock; 1564a13ea5b7SHugh Dickins 15656aab341eSLinus Torvalds page = vm_normal_page(vma, address, pte); 1566a13ea5b7SHugh Dickins if (unlikely(!page)) { 1567a13ea5b7SHugh Dickins if ((flags & FOLL_DUMP) || 156862eede62SHugh Dickins !is_zero_pfn(pte_pfn(pte))) 156989f5b7daSLinus Torvalds goto bad_page; 1570a13ea5b7SHugh Dickins page = pte_page(pte); 1571a13ea5b7SHugh Dickins } 1572deceb6cdSHugh Dickins 1573deceb6cdSHugh Dickins if (flags & FOLL_GET) 157470b50f94SAndrea Arcangeli get_page_foll(page); 1575deceb6cdSHugh Dickins if (flags & FOLL_TOUCH) { 1576deceb6cdSHugh Dickins if ((flags & FOLL_WRITE) && 1577deceb6cdSHugh Dickins !pte_dirty(pte) && !PageDirty(page)) 1578f33ea7f4SNick Piggin set_page_dirty(page); 1579bd775c42SKOSAKI Motohiro /* 1580bd775c42SKOSAKI Motohiro * pte_mkyoung() would be more correct here, but atomic care 1581bd775c42SKOSAKI Motohiro * is needed to avoid losing the dirty bit: it is easier to use 1582bd775c42SKOSAKI Motohiro * mark_page_accessed(). 1583bd775c42SKOSAKI Motohiro */ 15841da177e4SLinus Torvalds mark_page_accessed(page); 15851da177e4SLinus Torvalds } 1586a1fde08cSLinus Torvalds if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { 1587110d74a9SMichel Lespinasse /* 1588110d74a9SMichel Lespinasse * The preliminary mapping check is mainly to avoid the 1589110d74a9SMichel Lespinasse * pointless overhead of lock_page on the ZERO_PAGE 1590110d74a9SMichel Lespinasse * which might bounce very badly if there is contention. 1591110d74a9SMichel Lespinasse * 1592110d74a9SMichel Lespinasse * If the page is already locked, we don't need to 1593110d74a9SMichel Lespinasse * handle it now - vmscan will handle it later if and 1594110d74a9SMichel Lespinasse * when it attempts to reclaim the page. 1595110d74a9SMichel Lespinasse */ 1596110d74a9SMichel Lespinasse if (page->mapping && trylock_page(page)) { 1597110d74a9SMichel Lespinasse lru_add_drain(); /* push cached pages to LRU */ 1598110d74a9SMichel Lespinasse /* 1599e6c509f8SHugh Dickins * Because we lock page here, and migration is 1600e6c509f8SHugh Dickins * blocked by the pte's page reference, and we 1601e6c509f8SHugh Dickins * know the page is still mapped, we don't even 1602e6c509f8SHugh Dickins * need to check for file-cache page truncation. 1603110d74a9SMichel Lespinasse */ 1604110d74a9SMichel Lespinasse mlock_vma_page(page); 1605110d74a9SMichel Lespinasse unlock_page(page); 1606110d74a9SMichel Lespinasse } 1607110d74a9SMichel Lespinasse } 1608deceb6cdSHugh Dickins unlock: 1609deceb6cdSHugh Dickins pte_unmap_unlock(ptep, ptl); 16101da177e4SLinus Torvalds out: 1611deceb6cdSHugh Dickins return page; 1612deceb6cdSHugh Dickins 161389f5b7daSLinus Torvalds bad_page: 161489f5b7daSLinus Torvalds pte_unmap_unlock(ptep, ptl); 161589f5b7daSLinus Torvalds return ERR_PTR(-EFAULT); 161689f5b7daSLinus Torvalds 161789f5b7daSLinus Torvalds no_page: 161889f5b7daSLinus Torvalds pte_unmap_unlock(ptep, ptl); 161989f5b7daSLinus Torvalds if (!pte_none(pte)) 162089f5b7daSLinus Torvalds return page; 16218e4b9a60SHugh Dickins 1622deceb6cdSHugh Dickins no_page_table: 1623deceb6cdSHugh Dickins /* 1624deceb6cdSHugh Dickins * When core dumping an enormous anonymous area that nobody 16258e4b9a60SHugh Dickins * has touched so far, we don't want to allocate unnecessary pages or 16268e4b9a60SHugh Dickins * page tables. Return error instead of NULL to skip handle_mm_fault, 16278e4b9a60SHugh Dickins * then get_dump_page() will return NULL to leave a hole in the dump. 16288e4b9a60SHugh Dickins * But we can only make this optimization where a hole would surely 16298e4b9a60SHugh Dickins * be zero-filled if handle_mm_fault() actually did handle it. 1630deceb6cdSHugh Dickins */ 16318e4b9a60SHugh Dickins if ((flags & FOLL_DUMP) && 16328e4b9a60SHugh Dickins (!vma->vm_ops || !vma->vm_ops->fault)) 16338e4b9a60SHugh Dickins return ERR_PTR(-EFAULT); 1634deceb6cdSHugh Dickins return page; 16351da177e4SLinus Torvalds } 16361da177e4SLinus Torvalds 163795042f9eSLinus Torvalds static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr) 163895042f9eSLinus Torvalds { 1639a09a79f6SMikulas Patocka return stack_guard_page_start(vma, addr) || 1640a09a79f6SMikulas Patocka stack_guard_page_end(vma, addr+PAGE_SIZE); 164195042f9eSLinus Torvalds } 164295042f9eSLinus Torvalds 16430014bd99SHuang Ying /** 16440014bd99SHuang Ying * __get_user_pages() - pin user pages in memory 16450014bd99SHuang Ying * @tsk: task_struct of target task 16460014bd99SHuang Ying * @mm: mm_struct of target mm 16470014bd99SHuang Ying * @start: starting user address 16480014bd99SHuang Ying * @nr_pages: number of pages from start to pin 16490014bd99SHuang Ying * @gup_flags: flags modifying pin behaviour 16500014bd99SHuang Ying * @pages: array that receives pointers to the pages pinned. 16510014bd99SHuang Ying * Should be at least nr_pages long. Or NULL, if caller 16520014bd99SHuang Ying * only intends to ensure the pages are faulted in. 16530014bd99SHuang Ying * @vmas: array of pointers to vmas corresponding to each page. 16540014bd99SHuang Ying * Or NULL if the caller does not require them. 16550014bd99SHuang Ying * @nonblocking: whether waiting for disk IO or mmap_sem contention 16560014bd99SHuang Ying * 16570014bd99SHuang Ying * Returns number of pages pinned. This may be fewer than the number 16580014bd99SHuang Ying * requested. If nr_pages is 0 or negative, returns 0. If no pages 16590014bd99SHuang Ying * were pinned, returns -errno. Each page returned must be released 16600014bd99SHuang Ying * with a put_page() call when it is finished with. vmas will only 16610014bd99SHuang Ying * remain valid while mmap_sem is held. 16620014bd99SHuang Ying * 16630014bd99SHuang Ying * Must be called with mmap_sem held for read or write. 16640014bd99SHuang Ying * 16650014bd99SHuang Ying * __get_user_pages walks a process's page tables and takes a reference to 16660014bd99SHuang Ying * each struct page that each user address corresponds to at a given 16670014bd99SHuang Ying * instant. That is, it takes the page that would be accessed if a user 16680014bd99SHuang Ying * thread accesses the given user virtual address at that instant. 16690014bd99SHuang Ying * 16700014bd99SHuang Ying * This does not guarantee that the page exists in the user mappings when 16710014bd99SHuang Ying * __get_user_pages returns, and there may even be a completely different 16720014bd99SHuang Ying * page there in some cases (eg. if mmapped pagecache has been invalidated 16730014bd99SHuang Ying * and subsequently re faulted). However it does guarantee that the page 16740014bd99SHuang Ying * won't be freed completely. And mostly callers simply care that the page 16750014bd99SHuang Ying * contains data that was valid *at some point in time*. Typically, an IO 16760014bd99SHuang Ying * or similar operation cannot guarantee anything stronger anyway because 16770014bd99SHuang Ying * locks can't be held over the syscall boundary. 16780014bd99SHuang Ying * 16790014bd99SHuang Ying * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If 16800014bd99SHuang Ying * the page is written to, set_page_dirty (or set_page_dirty_lock, as 16810014bd99SHuang Ying * appropriate) must be called after the page is finished with, and 16820014bd99SHuang Ying * before put_page is called. 16830014bd99SHuang Ying * 16840014bd99SHuang Ying * If @nonblocking != NULL, __get_user_pages will not wait for disk IO 16850014bd99SHuang Ying * or mmap_sem contention, and if waiting is needed to pin all pages, 16860014bd99SHuang Ying * *@nonblocking will be set to 0. 16870014bd99SHuang Ying * 16880014bd99SHuang Ying * In most cases, get_user_pages or get_user_pages_fast should be used 16890014bd99SHuang Ying * instead of __get_user_pages. __get_user_pages should be used only if 16900014bd99SHuang Ying * you need some special @gup_flags. 16910014bd99SHuang Ying */ 169228a35716SMichel Lespinasse long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 169328a35716SMichel Lespinasse unsigned long start, unsigned long nr_pages, 169428a35716SMichel Lespinasse unsigned int gup_flags, struct page **pages, 169528a35716SMichel Lespinasse struct vm_area_struct **vmas, int *nonblocking) 16961da177e4SLinus Torvalds { 169728a35716SMichel Lespinasse long i; 169858fa879eSHugh Dickins unsigned long vm_flags; 1699240aadeeSMichel Lespinasse unsigned int page_mask; 17001da177e4SLinus Torvalds 170128a35716SMichel Lespinasse if (!nr_pages) 1702900cf086SJonathan Corbet return 0; 170358fa879eSHugh Dickins 170458fa879eSHugh Dickins VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); 170558fa879eSHugh Dickins 17061da177e4SLinus Torvalds /* 17071da177e4SLinus Torvalds * Require read or write permissions. 170858fa879eSHugh Dickins * If FOLL_FORCE is set, we only require the "MAY" flags. 17091da177e4SLinus Torvalds */ 171058fa879eSHugh Dickins vm_flags = (gup_flags & FOLL_WRITE) ? 171158fa879eSHugh Dickins (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 171258fa879eSHugh Dickins vm_flags &= (gup_flags & FOLL_FORCE) ? 171358fa879eSHugh Dickins (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 17140b9d7052SAndrea Arcangeli 17150b9d7052SAndrea Arcangeli /* 17160b9d7052SAndrea Arcangeli * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault 17170b9d7052SAndrea Arcangeli * would be called on PROT_NONE ranges. We must never invoke 17180b9d7052SAndrea Arcangeli * handle_mm_fault on PROT_NONE ranges or the NUMA hinting 17190b9d7052SAndrea Arcangeli * page faults would unprotect the PROT_NONE ranges if 17200b9d7052SAndrea Arcangeli * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd 17210b9d7052SAndrea Arcangeli * bitflag. So to avoid that, don't set FOLL_NUMA if 17220b9d7052SAndrea Arcangeli * FOLL_FORCE is set. 17230b9d7052SAndrea Arcangeli */ 17240b9d7052SAndrea Arcangeli if (!(gup_flags & FOLL_FORCE)) 17250b9d7052SAndrea Arcangeli gup_flags |= FOLL_NUMA; 17260b9d7052SAndrea Arcangeli 17271da177e4SLinus Torvalds i = 0; 17281da177e4SLinus Torvalds 17291da177e4SLinus Torvalds do { 17301da177e4SLinus Torvalds struct vm_area_struct *vma; 17311da177e4SLinus Torvalds 17321da177e4SLinus Torvalds vma = find_extend_vma(mm, start); 1733e7f22e20SStephen Wilson if (!vma && in_gate_area(mm, start)) { 17341da177e4SLinus Torvalds unsigned long pg = start & PAGE_MASK; 17351da177e4SLinus Torvalds pgd_t *pgd; 17361da177e4SLinus Torvalds pud_t *pud; 17371da177e4SLinus Torvalds pmd_t *pmd; 17381da177e4SLinus Torvalds pte_t *pte; 1739b291f000SNick Piggin 1740b291f000SNick Piggin /* user gate pages are read-only */ 174158fa879eSHugh Dickins if (gup_flags & FOLL_WRITE) 17421da177e4SLinus Torvalds return i ? : -EFAULT; 17431da177e4SLinus Torvalds if (pg > TASK_SIZE) 17441da177e4SLinus Torvalds pgd = pgd_offset_k(pg); 17451da177e4SLinus Torvalds else 17461da177e4SLinus Torvalds pgd = pgd_offset_gate(mm, pg); 17471da177e4SLinus Torvalds BUG_ON(pgd_none(*pgd)); 17481da177e4SLinus Torvalds pud = pud_offset(pgd, pg); 17491da177e4SLinus Torvalds BUG_ON(pud_none(*pud)); 17501da177e4SLinus Torvalds pmd = pmd_offset(pud, pg); 1751690dbe1cSHugh Dickins if (pmd_none(*pmd)) 1752690dbe1cSHugh Dickins return i ? : -EFAULT; 1753f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 17541da177e4SLinus Torvalds pte = pte_offset_map(pmd, pg); 1755690dbe1cSHugh Dickins if (pte_none(*pte)) { 1756690dbe1cSHugh Dickins pte_unmap(pte); 1757690dbe1cSHugh Dickins return i ? : -EFAULT; 1758690dbe1cSHugh Dickins } 175995042f9eSLinus Torvalds vma = get_gate_vma(mm); 17601da177e4SLinus Torvalds if (pages) { 1761de51257aSHugh Dickins struct page *page; 1762de51257aSHugh Dickins 176395042f9eSLinus Torvalds page = vm_normal_page(vma, start, *pte); 1764de51257aSHugh Dickins if (!page) { 1765de51257aSHugh Dickins if (!(gup_flags & FOLL_DUMP) && 1766de51257aSHugh Dickins is_zero_pfn(pte_pfn(*pte))) 1767de51257aSHugh Dickins page = pte_page(*pte); 1768de51257aSHugh Dickins else { 1769de51257aSHugh Dickins pte_unmap(pte); 1770de51257aSHugh Dickins return i ? : -EFAULT; 1771de51257aSHugh Dickins } 1772de51257aSHugh Dickins } 17736aab341eSLinus Torvalds pages[i] = page; 17746aab341eSLinus Torvalds get_page(page); 17751da177e4SLinus Torvalds } 17761da177e4SLinus Torvalds pte_unmap(pte); 1777240aadeeSMichel Lespinasse page_mask = 0; 177895042f9eSLinus Torvalds goto next_page; 17791da177e4SLinus Torvalds } 17801da177e4SLinus Torvalds 1781b291f000SNick Piggin if (!vma || 1782b291f000SNick Piggin (vma->vm_flags & (VM_IO | VM_PFNMAP)) || 17831c3aff1cSHugh Dickins !(vm_flags & vma->vm_flags)) 17841da177e4SLinus Torvalds return i ? : -EFAULT; 17851da177e4SLinus Torvalds 17862a15efc9SHugh Dickins if (is_vm_hugetlb_page(vma)) { 17872a15efc9SHugh Dickins i = follow_hugetlb_page(mm, vma, pages, vmas, 178858fa879eSHugh Dickins &start, &nr_pages, i, gup_flags); 17892a15efc9SHugh Dickins continue; 17902a15efc9SHugh Dickins } 1791deceb6cdSHugh Dickins 17921da177e4SLinus Torvalds do { 179308ef4729SHugh Dickins struct page *page; 179458fa879eSHugh Dickins unsigned int foll_flags = gup_flags; 1795240aadeeSMichel Lespinasse unsigned int page_increm; 17961da177e4SLinus Torvalds 1797462e00ccSEthan Solomita /* 17984779280dSYing Han * If we have a pending SIGKILL, don't keep faulting 17991c3aff1cSHugh Dickins * pages and potentially allocating memory. 1800462e00ccSEthan Solomita */ 18011c3aff1cSHugh Dickins if (unlikely(fatal_signal_pending(current))) 18024779280dSYing Han return i ? i : -ERESTARTSYS; 1803462e00ccSEthan Solomita 1804deceb6cdSHugh Dickins cond_resched(); 1805240aadeeSMichel Lespinasse while (!(page = follow_page_mask(vma, start, 1806240aadeeSMichel Lespinasse foll_flags, &page_mask))) { 1807a68d2ebcSLinus Torvalds int ret; 180853a7706dSMichel Lespinasse unsigned int fault_flags = 0; 180953a7706dSMichel Lespinasse 1810a09a79f6SMikulas Patocka /* For mlock, just skip the stack guard page. */ 1811a09a79f6SMikulas Patocka if (foll_flags & FOLL_MLOCK) { 1812a09a79f6SMikulas Patocka if (stack_guard_page(vma, start)) 1813a09a79f6SMikulas Patocka goto next_page; 1814a09a79f6SMikulas Patocka } 181553a7706dSMichel Lespinasse if (foll_flags & FOLL_WRITE) 181653a7706dSMichel Lespinasse fault_flags |= FAULT_FLAG_WRITE; 181753a7706dSMichel Lespinasse if (nonblocking) 181853a7706dSMichel Lespinasse fault_flags |= FAULT_FLAG_ALLOW_RETRY; 1819318b275fSGleb Natapov if (foll_flags & FOLL_NOWAIT) 1820318b275fSGleb Natapov fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT); 1821d06063ccSLinus Torvalds 1822d26ed650SHugh Dickins ret = handle_mm_fault(mm, vma, start, 182353a7706dSMichel Lespinasse fault_flags); 1824d26ed650SHugh Dickins 182583c54070SNick Piggin if (ret & VM_FAULT_ERROR) { 182683c54070SNick Piggin if (ret & VM_FAULT_OOM) 182783c54070SNick Piggin return i ? i : -ENOMEM; 182869ebb83eSHuang Ying if (ret & (VM_FAULT_HWPOISON | 182969ebb83eSHuang Ying VM_FAULT_HWPOISON_LARGE)) { 183069ebb83eSHuang Ying if (i) 183169ebb83eSHuang Ying return i; 183269ebb83eSHuang Ying else if (gup_flags & FOLL_HWPOISON) 183369ebb83eSHuang Ying return -EHWPOISON; 183469ebb83eSHuang Ying else 183569ebb83eSHuang Ying return -EFAULT; 183669ebb83eSHuang Ying } 183769ebb83eSHuang Ying if (ret & VM_FAULT_SIGBUS) 183883c54070SNick Piggin return i ? i : -EFAULT; 183983c54070SNick Piggin BUG(); 184083c54070SNick Piggin } 1841e7f22e20SStephen Wilson 1842e7f22e20SStephen Wilson if (tsk) { 184383c54070SNick Piggin if (ret & VM_FAULT_MAJOR) 184483c54070SNick Piggin tsk->maj_flt++; 184583c54070SNick Piggin else 184683c54070SNick Piggin tsk->min_flt++; 1847e7f22e20SStephen Wilson } 184883c54070SNick Piggin 184953a7706dSMichel Lespinasse if (ret & VM_FAULT_RETRY) { 1850318b275fSGleb Natapov if (nonblocking) 185153a7706dSMichel Lespinasse *nonblocking = 0; 185253a7706dSMichel Lespinasse return i; 185353a7706dSMichel Lespinasse } 185453a7706dSMichel Lespinasse 1855f33ea7f4SNick Piggin /* 185683c54070SNick Piggin * The VM_FAULT_WRITE bit tells us that 185783c54070SNick Piggin * do_wp_page has broken COW when necessary, 185883c54070SNick Piggin * even if maybe_mkwrite decided not to set 185983c54070SNick Piggin * pte_write. We can thus safely do subsequent 1860878b63acSHugh Dickins * page lookups as if they were reads. But only 1861878b63acSHugh Dickins * do so when looping for pte_write is futile: 1862878b63acSHugh Dickins * in some cases userspace may also be wanting 1863878b63acSHugh Dickins * to write to the gotten user page, which a 1864878b63acSHugh Dickins * read fault here might prevent (a readonly 1865878b63acSHugh Dickins * page might get reCOWed by userspace write). 1866f33ea7f4SNick Piggin */ 1867878b63acSHugh Dickins if ((ret & VM_FAULT_WRITE) && 1868878b63acSHugh Dickins !(vma->vm_flags & VM_WRITE)) 1869deceb6cdSHugh Dickins foll_flags &= ~FOLL_WRITE; 1870a68d2ebcSLinus Torvalds 18717f7bbbe5SBenjamin Herrenschmidt cond_resched(); 18721da177e4SLinus Torvalds } 187389f5b7daSLinus Torvalds if (IS_ERR(page)) 187489f5b7daSLinus Torvalds return i ? i : PTR_ERR(page); 18751da177e4SLinus Torvalds if (pages) { 187608ef4729SHugh Dickins pages[i] = page; 187703beb076SJames Bottomley 1878a6f36be3SRussell King flush_anon_page(vma, page, start); 187908ef4729SHugh Dickins flush_dcache_page(page); 1880240aadeeSMichel Lespinasse page_mask = 0; 18811da177e4SLinus Torvalds } 188295042f9eSLinus Torvalds next_page: 1883240aadeeSMichel Lespinasse if (vmas) { 18841da177e4SLinus Torvalds vmas[i] = vma; 1885240aadeeSMichel Lespinasse page_mask = 0; 1886240aadeeSMichel Lespinasse } 1887240aadeeSMichel Lespinasse page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask); 1888240aadeeSMichel Lespinasse if (page_increm > nr_pages) 1889240aadeeSMichel Lespinasse page_increm = nr_pages; 1890240aadeeSMichel Lespinasse i += page_increm; 1891240aadeeSMichel Lespinasse start += page_increm * PAGE_SIZE; 1892240aadeeSMichel Lespinasse nr_pages -= page_increm; 18939d73777eSPeter Zijlstra } while (nr_pages && start < vma->vm_end); 18949d73777eSPeter Zijlstra } while (nr_pages); 18951da177e4SLinus Torvalds return i; 18961da177e4SLinus Torvalds } 18970014bd99SHuang Ying EXPORT_SYMBOL(__get_user_pages); 1898b291f000SNick Piggin 18992efaca92SBenjamin Herrenschmidt /* 19002efaca92SBenjamin Herrenschmidt * fixup_user_fault() - manually resolve a user page fault 19012efaca92SBenjamin Herrenschmidt * @tsk: the task_struct to use for page fault accounting, or 19022efaca92SBenjamin Herrenschmidt * NULL if faults are not to be recorded. 19032efaca92SBenjamin Herrenschmidt * @mm: mm_struct of target mm 19042efaca92SBenjamin Herrenschmidt * @address: user address 19052efaca92SBenjamin Herrenschmidt * @fault_flags:flags to pass down to handle_mm_fault() 19062efaca92SBenjamin Herrenschmidt * 19072efaca92SBenjamin Herrenschmidt * This is meant to be called in the specific scenario where for locking reasons 19082efaca92SBenjamin Herrenschmidt * we try to access user memory in atomic context (within a pagefault_disable() 19092efaca92SBenjamin Herrenschmidt * section), this returns -EFAULT, and we want to resolve the user fault before 19102efaca92SBenjamin Herrenschmidt * trying again. 19112efaca92SBenjamin Herrenschmidt * 19122efaca92SBenjamin Herrenschmidt * Typically this is meant to be used by the futex code. 19132efaca92SBenjamin Herrenschmidt * 19142efaca92SBenjamin Herrenschmidt * The main difference with get_user_pages() is that this function will 19152efaca92SBenjamin Herrenschmidt * unconditionally call handle_mm_fault() which will in turn perform all the 19162efaca92SBenjamin Herrenschmidt * necessary SW fixup of the dirty and young bits in the PTE, while 19172efaca92SBenjamin Herrenschmidt * handle_mm_fault() only guarantees to update these in the struct page. 19182efaca92SBenjamin Herrenschmidt * 19192efaca92SBenjamin Herrenschmidt * This is important for some architectures where those bits also gate the 19202efaca92SBenjamin Herrenschmidt * access permission to the page because they are maintained in software. On 19212efaca92SBenjamin Herrenschmidt * such architectures, gup() will not be enough to make a subsequent access 19222efaca92SBenjamin Herrenschmidt * succeed. 19232efaca92SBenjamin Herrenschmidt * 19242efaca92SBenjamin Herrenschmidt * This should be called with the mm_sem held for read. 19252efaca92SBenjamin Herrenschmidt */ 19262efaca92SBenjamin Herrenschmidt int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, 19272efaca92SBenjamin Herrenschmidt unsigned long address, unsigned int fault_flags) 19282efaca92SBenjamin Herrenschmidt { 19292efaca92SBenjamin Herrenschmidt struct vm_area_struct *vma; 19302efaca92SBenjamin Herrenschmidt int ret; 19312efaca92SBenjamin Herrenschmidt 19322efaca92SBenjamin Herrenschmidt vma = find_extend_vma(mm, address); 19332efaca92SBenjamin Herrenschmidt if (!vma || address < vma->vm_start) 19342efaca92SBenjamin Herrenschmidt return -EFAULT; 19352efaca92SBenjamin Herrenschmidt 19362efaca92SBenjamin Herrenschmidt ret = handle_mm_fault(mm, vma, address, fault_flags); 19372efaca92SBenjamin Herrenschmidt if (ret & VM_FAULT_ERROR) { 19382efaca92SBenjamin Herrenschmidt if (ret & VM_FAULT_OOM) 19392efaca92SBenjamin Herrenschmidt return -ENOMEM; 19402efaca92SBenjamin Herrenschmidt if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) 19412efaca92SBenjamin Herrenschmidt return -EHWPOISON; 19422efaca92SBenjamin Herrenschmidt if (ret & VM_FAULT_SIGBUS) 19432efaca92SBenjamin Herrenschmidt return -EFAULT; 19442efaca92SBenjamin Herrenschmidt BUG(); 19452efaca92SBenjamin Herrenschmidt } 19462efaca92SBenjamin Herrenschmidt if (tsk) { 19472efaca92SBenjamin Herrenschmidt if (ret & VM_FAULT_MAJOR) 19482efaca92SBenjamin Herrenschmidt tsk->maj_flt++; 19492efaca92SBenjamin Herrenschmidt else 19502efaca92SBenjamin Herrenschmidt tsk->min_flt++; 19512efaca92SBenjamin Herrenschmidt } 19522efaca92SBenjamin Herrenschmidt return 0; 19532efaca92SBenjamin Herrenschmidt } 19542efaca92SBenjamin Herrenschmidt 19552efaca92SBenjamin Herrenschmidt /* 1956d2bf6be8SNick Piggin * get_user_pages() - pin user pages in memory 1957e7f22e20SStephen Wilson * @tsk: the task_struct to use for page fault accounting, or 1958e7f22e20SStephen Wilson * NULL if faults are not to be recorded. 1959d2bf6be8SNick Piggin * @mm: mm_struct of target mm 1960d2bf6be8SNick Piggin * @start: starting user address 19619d73777eSPeter Zijlstra * @nr_pages: number of pages from start to pin 1962d2bf6be8SNick Piggin * @write: whether pages will be written to by the caller 1963d2bf6be8SNick Piggin * @force: whether to force write access even if user mapping is 1964d2bf6be8SNick Piggin * readonly. This will result in the page being COWed even 1965d2bf6be8SNick Piggin * in MAP_SHARED mappings. You do not want this. 1966d2bf6be8SNick Piggin * @pages: array that receives pointers to the pages pinned. 1967d2bf6be8SNick Piggin * Should be at least nr_pages long. Or NULL, if caller 1968d2bf6be8SNick Piggin * only intends to ensure the pages are faulted in. 1969d2bf6be8SNick Piggin * @vmas: array of pointers to vmas corresponding to each page. 1970d2bf6be8SNick Piggin * Or NULL if the caller does not require them. 1971d2bf6be8SNick Piggin * 1972d2bf6be8SNick Piggin * Returns number of pages pinned. This may be fewer than the number 19739d73777eSPeter Zijlstra * requested. If nr_pages is 0 or negative, returns 0. If no pages 1974d2bf6be8SNick Piggin * were pinned, returns -errno. Each page returned must be released 1975d2bf6be8SNick Piggin * with a put_page() call when it is finished with. vmas will only 1976d2bf6be8SNick Piggin * remain valid while mmap_sem is held. 1977d2bf6be8SNick Piggin * 1978d2bf6be8SNick Piggin * Must be called with mmap_sem held for read or write. 1979d2bf6be8SNick Piggin * 1980d2bf6be8SNick Piggin * get_user_pages walks a process's page tables and takes a reference to 1981d2bf6be8SNick Piggin * each struct page that each user address corresponds to at a given 1982d2bf6be8SNick Piggin * instant. That is, it takes the page that would be accessed if a user 1983d2bf6be8SNick Piggin * thread accesses the given user virtual address at that instant. 1984d2bf6be8SNick Piggin * 1985d2bf6be8SNick Piggin * This does not guarantee that the page exists in the user mappings when 1986d2bf6be8SNick Piggin * get_user_pages returns, and there may even be a completely different 1987d2bf6be8SNick Piggin * page there in some cases (eg. if mmapped pagecache has been invalidated 1988d2bf6be8SNick Piggin * and subsequently re faulted). However it does guarantee that the page 1989d2bf6be8SNick Piggin * won't be freed completely. And mostly callers simply care that the page 1990d2bf6be8SNick Piggin * contains data that was valid *at some point in time*. Typically, an IO 1991d2bf6be8SNick Piggin * or similar operation cannot guarantee anything stronger anyway because 1992d2bf6be8SNick Piggin * locks can't be held over the syscall boundary. 1993d2bf6be8SNick Piggin * 1994d2bf6be8SNick Piggin * If write=0, the page must not be written to. If the page is written to, 1995d2bf6be8SNick Piggin * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called 1996d2bf6be8SNick Piggin * after the page is finished with, and before put_page is called. 1997d2bf6be8SNick Piggin * 1998d2bf6be8SNick Piggin * get_user_pages is typically used for fewer-copy IO operations, to get a 1999d2bf6be8SNick Piggin * handle on the memory by some means other than accesses via the user virtual 2000d2bf6be8SNick Piggin * addresses. The pages may be submitted for DMA to devices or accessed via 2001d2bf6be8SNick Piggin * their kernel linear mapping (via the kmap APIs). Care should be taken to 2002d2bf6be8SNick Piggin * use the correct cache flushing APIs. 2003d2bf6be8SNick Piggin * 2004d2bf6be8SNick Piggin * See also get_user_pages_fast, for performance critical applications. 2005d2bf6be8SNick Piggin */ 200628a35716SMichel Lespinasse long get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 200728a35716SMichel Lespinasse unsigned long start, unsigned long nr_pages, int write, 200828a35716SMichel Lespinasse int force, struct page **pages, struct vm_area_struct **vmas) 2009b291f000SNick Piggin { 201058fa879eSHugh Dickins int flags = FOLL_TOUCH; 2011b291f000SNick Piggin 201258fa879eSHugh Dickins if (pages) 201358fa879eSHugh Dickins flags |= FOLL_GET; 2014b291f000SNick Piggin if (write) 201558fa879eSHugh Dickins flags |= FOLL_WRITE; 2016b291f000SNick Piggin if (force) 201758fa879eSHugh Dickins flags |= FOLL_FORCE; 2018b291f000SNick Piggin 201953a7706dSMichel Lespinasse return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas, 202053a7706dSMichel Lespinasse NULL); 2021b291f000SNick Piggin } 20221da177e4SLinus Torvalds EXPORT_SYMBOL(get_user_pages); 20231da177e4SLinus Torvalds 2024f3e8fccdSHugh Dickins /** 2025f3e8fccdSHugh Dickins * get_dump_page() - pin user page in memory while writing it to core dump 2026f3e8fccdSHugh Dickins * @addr: user address 2027f3e8fccdSHugh Dickins * 2028f3e8fccdSHugh Dickins * Returns struct page pointer of user page pinned for dump, 2029f3e8fccdSHugh Dickins * to be freed afterwards by page_cache_release() or put_page(). 2030f3e8fccdSHugh Dickins * 2031f3e8fccdSHugh Dickins * Returns NULL on any kind of failure - a hole must then be inserted into 2032f3e8fccdSHugh Dickins * the corefile, to preserve alignment with its headers; and also returns 2033f3e8fccdSHugh Dickins * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - 2034f3e8fccdSHugh Dickins * allowing a hole to be left in the corefile to save diskspace. 2035f3e8fccdSHugh Dickins * 2036f3e8fccdSHugh Dickins * Called without mmap_sem, but after all other threads have been killed. 2037f3e8fccdSHugh Dickins */ 2038f3e8fccdSHugh Dickins #ifdef CONFIG_ELF_CORE 2039f3e8fccdSHugh Dickins struct page *get_dump_page(unsigned long addr) 2040f3e8fccdSHugh Dickins { 2041f3e8fccdSHugh Dickins struct vm_area_struct *vma; 2042f3e8fccdSHugh Dickins struct page *page; 2043f3e8fccdSHugh Dickins 2044f3e8fccdSHugh Dickins if (__get_user_pages(current, current->mm, addr, 1, 204553a7706dSMichel Lespinasse FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma, 204653a7706dSMichel Lespinasse NULL) < 1) 2047f3e8fccdSHugh Dickins return NULL; 2048f3e8fccdSHugh Dickins flush_cache_page(vma, addr, page_to_pfn(page)); 2049f3e8fccdSHugh Dickins return page; 2050f3e8fccdSHugh Dickins } 2051f3e8fccdSHugh Dickins #endif /* CONFIG_ELF_CORE */ 2052f3e8fccdSHugh Dickins 205325ca1d6cSNamhyung Kim pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, 2054920c7a5dSHarvey Harrison spinlock_t **ptl) 2055c9cfcddfSLinus Torvalds { 2056c9cfcddfSLinus Torvalds pgd_t * pgd = pgd_offset(mm, addr); 2057c9cfcddfSLinus Torvalds pud_t * pud = pud_alloc(mm, pgd, addr); 2058c9cfcddfSLinus Torvalds if (pud) { 205949c91fb0STrond Myklebust pmd_t * pmd = pmd_alloc(mm, pud, addr); 2060f66055abSAndrea Arcangeli if (pmd) { 2061f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 2062c9cfcddfSLinus Torvalds return pte_alloc_map_lock(mm, pmd, addr, ptl); 2063c9cfcddfSLinus Torvalds } 2064f66055abSAndrea Arcangeli } 2065c9cfcddfSLinus Torvalds return NULL; 2066c9cfcddfSLinus Torvalds } 2067c9cfcddfSLinus Torvalds 20681da177e4SLinus Torvalds /* 2069238f58d8SLinus Torvalds * This is the old fallback for page remapping. 2070238f58d8SLinus Torvalds * 2071238f58d8SLinus Torvalds * For historical reasons, it only allows reserved pages. Only 2072238f58d8SLinus Torvalds * old drivers should use this, and they needed to mark their 2073238f58d8SLinus Torvalds * pages reserved for the old functions anyway. 2074238f58d8SLinus Torvalds */ 2075423bad60SNick Piggin static int insert_page(struct vm_area_struct *vma, unsigned long addr, 2076423bad60SNick Piggin struct page *page, pgprot_t prot) 2077238f58d8SLinus Torvalds { 2078423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2079238f58d8SLinus Torvalds int retval; 2080238f58d8SLinus Torvalds pte_t *pte; 2081238f58d8SLinus Torvalds spinlock_t *ptl; 2082238f58d8SLinus Torvalds 2083238f58d8SLinus Torvalds retval = -EINVAL; 2084a145dd41SLinus Torvalds if (PageAnon(page)) 20855b4e655eSKAMEZAWA Hiroyuki goto out; 2086238f58d8SLinus Torvalds retval = -ENOMEM; 2087238f58d8SLinus Torvalds flush_dcache_page(page); 2088c9cfcddfSLinus Torvalds pte = get_locked_pte(mm, addr, &ptl); 2089238f58d8SLinus Torvalds if (!pte) 20905b4e655eSKAMEZAWA Hiroyuki goto out; 2091238f58d8SLinus Torvalds retval = -EBUSY; 2092238f58d8SLinus Torvalds if (!pte_none(*pte)) 2093238f58d8SLinus Torvalds goto out_unlock; 2094238f58d8SLinus Torvalds 2095238f58d8SLinus Torvalds /* Ok, finally just insert the thing.. */ 2096238f58d8SLinus Torvalds get_page(page); 209734e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_FILEPAGES); 2098238f58d8SLinus Torvalds page_add_file_rmap(page); 2099238f58d8SLinus Torvalds set_pte_at(mm, addr, pte, mk_pte(page, prot)); 2100238f58d8SLinus Torvalds 2101238f58d8SLinus Torvalds retval = 0; 21028a9f3ccdSBalbir Singh pte_unmap_unlock(pte, ptl); 21038a9f3ccdSBalbir Singh return retval; 2104238f58d8SLinus Torvalds out_unlock: 2105238f58d8SLinus Torvalds pte_unmap_unlock(pte, ptl); 2106238f58d8SLinus Torvalds out: 2107238f58d8SLinus Torvalds return retval; 2108238f58d8SLinus Torvalds } 2109238f58d8SLinus Torvalds 2110bfa5bf6dSRolf Eike Beer /** 2111bfa5bf6dSRolf Eike Beer * vm_insert_page - insert single page into user vma 2112bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2113bfa5bf6dSRolf Eike Beer * @addr: target user address of this page 2114bfa5bf6dSRolf Eike Beer * @page: source kernel page 2115bfa5bf6dSRolf Eike Beer * 2116a145dd41SLinus Torvalds * This allows drivers to insert individual pages they've allocated 2117a145dd41SLinus Torvalds * into a user vma. 2118a145dd41SLinus Torvalds * 2119a145dd41SLinus Torvalds * The page has to be a nice clean _individual_ kernel allocation. 2120a145dd41SLinus Torvalds * If you allocate a compound page, you need to have marked it as 2121a145dd41SLinus Torvalds * such (__GFP_COMP), or manually just split the page up yourself 21228dfcc9baSNick Piggin * (see split_page()). 2123a145dd41SLinus Torvalds * 2124a145dd41SLinus Torvalds * NOTE! Traditionally this was done with "remap_pfn_range()" which 2125a145dd41SLinus Torvalds * took an arbitrary page protection parameter. This doesn't allow 2126a145dd41SLinus Torvalds * that. Your vma protection will have to be set up correctly, which 2127a145dd41SLinus Torvalds * means that if you want a shared writable mapping, you'd better 2128a145dd41SLinus Torvalds * ask for a shared writable mapping! 2129a145dd41SLinus Torvalds * 2130a145dd41SLinus Torvalds * The page does not need to be reserved. 21314b6e1e37SKonstantin Khlebnikov * 21324b6e1e37SKonstantin Khlebnikov * Usually this function is called from f_op->mmap() handler 21334b6e1e37SKonstantin Khlebnikov * under mm->mmap_sem write-lock, so it can change vma->vm_flags. 21344b6e1e37SKonstantin Khlebnikov * Caller must set VM_MIXEDMAP on vma if it wants to call this 21354b6e1e37SKonstantin Khlebnikov * function from other places, for example from page-fault handler. 2136a145dd41SLinus Torvalds */ 2137423bad60SNick Piggin int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, 2138423bad60SNick Piggin struct page *page) 2139a145dd41SLinus Torvalds { 2140a145dd41SLinus Torvalds if (addr < vma->vm_start || addr >= vma->vm_end) 2141a145dd41SLinus Torvalds return -EFAULT; 2142a145dd41SLinus Torvalds if (!page_count(page)) 2143a145dd41SLinus Torvalds return -EINVAL; 21444b6e1e37SKonstantin Khlebnikov if (!(vma->vm_flags & VM_MIXEDMAP)) { 21454b6e1e37SKonstantin Khlebnikov BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem)); 21464b6e1e37SKonstantin Khlebnikov BUG_ON(vma->vm_flags & VM_PFNMAP); 21474b6e1e37SKonstantin Khlebnikov vma->vm_flags |= VM_MIXEDMAP; 21484b6e1e37SKonstantin Khlebnikov } 2149423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2150a145dd41SLinus Torvalds } 2151e3c3374fSLinus Torvalds EXPORT_SYMBOL(vm_insert_page); 2152a145dd41SLinus Torvalds 2153423bad60SNick Piggin static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2154423bad60SNick Piggin unsigned long pfn, pgprot_t prot) 2155423bad60SNick Piggin { 2156423bad60SNick Piggin struct mm_struct *mm = vma->vm_mm; 2157423bad60SNick Piggin int retval; 2158423bad60SNick Piggin pte_t *pte, entry; 2159423bad60SNick Piggin spinlock_t *ptl; 2160423bad60SNick Piggin 2161423bad60SNick Piggin retval = -ENOMEM; 2162423bad60SNick Piggin pte = get_locked_pte(mm, addr, &ptl); 2163423bad60SNick Piggin if (!pte) 2164423bad60SNick Piggin goto out; 2165423bad60SNick Piggin retval = -EBUSY; 2166423bad60SNick Piggin if (!pte_none(*pte)) 2167423bad60SNick Piggin goto out_unlock; 2168423bad60SNick Piggin 2169423bad60SNick Piggin /* Ok, finally just insert the thing.. */ 2170423bad60SNick Piggin entry = pte_mkspecial(pfn_pte(pfn, prot)); 2171423bad60SNick Piggin set_pte_at(mm, addr, pte, entry); 21724b3073e1SRussell King update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ 2173423bad60SNick Piggin 2174423bad60SNick Piggin retval = 0; 2175423bad60SNick Piggin out_unlock: 2176423bad60SNick Piggin pte_unmap_unlock(pte, ptl); 2177423bad60SNick Piggin out: 2178423bad60SNick Piggin return retval; 2179423bad60SNick Piggin } 2180423bad60SNick Piggin 2181e0dc0d8fSNick Piggin /** 2182e0dc0d8fSNick Piggin * vm_insert_pfn - insert single pfn into user vma 2183e0dc0d8fSNick Piggin * @vma: user vma to map to 2184e0dc0d8fSNick Piggin * @addr: target user address of this page 2185e0dc0d8fSNick Piggin * @pfn: source kernel pfn 2186e0dc0d8fSNick Piggin * 2187c462f179SRobert P. J. Day * Similar to vm_insert_page, this allows drivers to insert individual pages 2188e0dc0d8fSNick Piggin * they've allocated into a user vma. Same comments apply. 2189e0dc0d8fSNick Piggin * 2190e0dc0d8fSNick Piggin * This function should only be called from a vm_ops->fault handler, and 2191e0dc0d8fSNick Piggin * in that case the handler should return NULL. 21920d71d10aSNick Piggin * 21930d71d10aSNick Piggin * vma cannot be a COW mapping. 21940d71d10aSNick Piggin * 21950d71d10aSNick Piggin * As this is called only for pages that do not currently exist, we 21960d71d10aSNick Piggin * do not need to flush old virtual caches or the TLB. 2197e0dc0d8fSNick Piggin */ 2198e0dc0d8fSNick Piggin int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 2199e0dc0d8fSNick Piggin unsigned long pfn) 2200e0dc0d8fSNick Piggin { 22012ab64037Svenkatesh.pallipadi@intel.com int ret; 2202e4b866edSvenkatesh.pallipadi@intel.com pgprot_t pgprot = vma->vm_page_prot; 22037e675137SNick Piggin /* 22047e675137SNick Piggin * Technically, architectures with pte_special can avoid all these 22057e675137SNick Piggin * restrictions (same for remap_pfn_range). However we would like 22067e675137SNick Piggin * consistency in testing and feature parity among all, so we should 22077e675137SNick Piggin * try to keep these invariants in place for everybody. 22087e675137SNick Piggin */ 2209b379d790SJared Hulbert BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); 2210b379d790SJared Hulbert BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == 2211b379d790SJared Hulbert (VM_PFNMAP|VM_MIXEDMAP)); 2212b379d790SJared Hulbert BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); 2213b379d790SJared Hulbert BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); 2214e0dc0d8fSNick Piggin 2215423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 2216423bad60SNick Piggin return -EFAULT; 22175180da41SSuresh Siddha if (track_pfn_insert(vma, &pgprot, pfn)) 22182ab64037Svenkatesh.pallipadi@intel.com return -EINVAL; 22192ab64037Svenkatesh.pallipadi@intel.com 2220e4b866edSvenkatesh.pallipadi@intel.com ret = insert_pfn(vma, addr, pfn, pgprot); 22212ab64037Svenkatesh.pallipadi@intel.com 22222ab64037Svenkatesh.pallipadi@intel.com return ret; 2223e0dc0d8fSNick Piggin } 2224e0dc0d8fSNick Piggin EXPORT_SYMBOL(vm_insert_pfn); 2225e0dc0d8fSNick Piggin 2226423bad60SNick Piggin int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, 2227423bad60SNick Piggin unsigned long pfn) 2228423bad60SNick Piggin { 2229423bad60SNick Piggin BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); 2230423bad60SNick Piggin 2231423bad60SNick Piggin if (addr < vma->vm_start || addr >= vma->vm_end) 2232423bad60SNick Piggin return -EFAULT; 2233423bad60SNick Piggin 2234423bad60SNick Piggin /* 2235423bad60SNick Piggin * If we don't have pte special, then we have to use the pfn_valid() 2236423bad60SNick Piggin * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* 2237423bad60SNick Piggin * refcount the page if pfn_valid is true (hence insert_page rather 223862eede62SHugh Dickins * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP 223962eede62SHugh Dickins * without pte special, it would there be refcounted as a normal page. 2240423bad60SNick Piggin */ 2241423bad60SNick Piggin if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { 2242423bad60SNick Piggin struct page *page; 2243423bad60SNick Piggin 2244423bad60SNick Piggin page = pfn_to_page(pfn); 2245423bad60SNick Piggin return insert_page(vma, addr, page, vma->vm_page_prot); 2246423bad60SNick Piggin } 2247423bad60SNick Piggin return insert_pfn(vma, addr, pfn, vma->vm_page_prot); 2248423bad60SNick Piggin } 2249423bad60SNick Piggin EXPORT_SYMBOL(vm_insert_mixed); 2250423bad60SNick Piggin 2251a145dd41SLinus Torvalds /* 22521da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 22531da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 22541da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 22551da177e4SLinus Torvalds */ 22561da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 22571da177e4SLinus Torvalds unsigned long addr, unsigned long end, 22581da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 22591da177e4SLinus Torvalds { 22601da177e4SLinus Torvalds pte_t *pte; 2261c74df32cSHugh Dickins spinlock_t *ptl; 22621da177e4SLinus Torvalds 2263c74df32cSHugh Dickins pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 22641da177e4SLinus Torvalds if (!pte) 22651da177e4SLinus Torvalds return -ENOMEM; 22666606c3e0SZachary Amsden arch_enter_lazy_mmu_mode(); 22671da177e4SLinus Torvalds do { 22681da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 22697e675137SNick Piggin set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); 22701da177e4SLinus Torvalds pfn++; 22711da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 22726606c3e0SZachary Amsden arch_leave_lazy_mmu_mode(); 2273c74df32cSHugh Dickins pte_unmap_unlock(pte - 1, ptl); 22741da177e4SLinus Torvalds return 0; 22751da177e4SLinus Torvalds } 22761da177e4SLinus Torvalds 22771da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 22781da177e4SLinus Torvalds unsigned long addr, unsigned long end, 22791da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 22801da177e4SLinus Torvalds { 22811da177e4SLinus Torvalds pmd_t *pmd; 22821da177e4SLinus Torvalds unsigned long next; 22831da177e4SLinus Torvalds 22841da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 22851da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 22861da177e4SLinus Torvalds if (!pmd) 22871da177e4SLinus Torvalds return -ENOMEM; 2288f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 22891da177e4SLinus Torvalds do { 22901da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 22911da177e4SLinus Torvalds if (remap_pte_range(mm, pmd, addr, next, 22921da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 22931da177e4SLinus Torvalds return -ENOMEM; 22941da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 22951da177e4SLinus Torvalds return 0; 22961da177e4SLinus Torvalds } 22971da177e4SLinus Torvalds 22981da177e4SLinus Torvalds static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 22991da177e4SLinus Torvalds unsigned long addr, unsigned long end, 23001da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 23011da177e4SLinus Torvalds { 23021da177e4SLinus Torvalds pud_t *pud; 23031da177e4SLinus Torvalds unsigned long next; 23041da177e4SLinus Torvalds 23051da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23061da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, addr); 23071da177e4SLinus Torvalds if (!pud) 23081da177e4SLinus Torvalds return -ENOMEM; 23091da177e4SLinus Torvalds do { 23101da177e4SLinus Torvalds next = pud_addr_end(addr, end); 23111da177e4SLinus Torvalds if (remap_pmd_range(mm, pud, addr, next, 23121da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 23131da177e4SLinus Torvalds return -ENOMEM; 23141da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 23151da177e4SLinus Torvalds return 0; 23161da177e4SLinus Torvalds } 23171da177e4SLinus Torvalds 2318bfa5bf6dSRolf Eike Beer /** 2319bfa5bf6dSRolf Eike Beer * remap_pfn_range - remap kernel memory to userspace 2320bfa5bf6dSRolf Eike Beer * @vma: user vma to map to 2321bfa5bf6dSRolf Eike Beer * @addr: target user address to start at 2322bfa5bf6dSRolf Eike Beer * @pfn: physical address of kernel memory 2323bfa5bf6dSRolf Eike Beer * @size: size of map area 2324bfa5bf6dSRolf Eike Beer * @prot: page protection flags for this mapping 2325bfa5bf6dSRolf Eike Beer * 2326bfa5bf6dSRolf Eike Beer * Note: this is only safe if the mm semaphore is held when called. 2327bfa5bf6dSRolf Eike Beer */ 23281da177e4SLinus Torvalds int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 23291da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 23301da177e4SLinus Torvalds { 23311da177e4SLinus Torvalds pgd_t *pgd; 23321da177e4SLinus Torvalds unsigned long next; 23332d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 23341da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 23351da177e4SLinus Torvalds int err; 23361da177e4SLinus Torvalds 23371da177e4SLinus Torvalds /* 23381da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 23391da177e4SLinus Torvalds * rest of the world about it: 23401da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 23411da177e4SLinus Torvalds * (accesses can have side effects). 23426aab341eSLinus Torvalds * VM_PFNMAP tells the core MM that the base pages are just 23436aab341eSLinus Torvalds * raw PFN mappings, and do not have a "struct page" associated 23446aab341eSLinus Torvalds * with them. 2345314e51b9SKonstantin Khlebnikov * VM_DONTEXPAND 2346314e51b9SKonstantin Khlebnikov * Disable vma merging and expanding with mremap(). 2347314e51b9SKonstantin Khlebnikov * VM_DONTDUMP 2348314e51b9SKonstantin Khlebnikov * Omit vma from core dump, even when VM_IO turned off. 2349fb155c16SLinus Torvalds * 2350fb155c16SLinus Torvalds * There's a horrible special case to handle copy-on-write 2351fb155c16SLinus Torvalds * behaviour that some programs depend on. We mark the "original" 2352fb155c16SLinus Torvalds * un-COW'ed pages by matching them up with "vma->vm_pgoff". 2353b3b9c293SKonstantin Khlebnikov * See vm_normal_page() for details. 23541da177e4SLinus Torvalds */ 2355b3b9c293SKonstantin Khlebnikov if (is_cow_mapping(vma->vm_flags)) { 2356b3b9c293SKonstantin Khlebnikov if (addr != vma->vm_start || end != vma->vm_end) 2357b3b9c293SKonstantin Khlebnikov return -EINVAL; 23586aab341eSLinus Torvalds vma->vm_pgoff = pfn; 2359b3b9c293SKonstantin Khlebnikov } 2360b3b9c293SKonstantin Khlebnikov 2361b3b9c293SKonstantin Khlebnikov err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); 2362b3b9c293SKonstantin Khlebnikov if (err) 23633c8bb73aSvenkatesh.pallipadi@intel.com return -EINVAL; 2364fb155c16SLinus Torvalds 2365314e51b9SKonstantin Khlebnikov vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 23661da177e4SLinus Torvalds 23671da177e4SLinus Torvalds BUG_ON(addr >= end); 23681da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 23691da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 23701da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 23711da177e4SLinus Torvalds do { 23721da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 23731da177e4SLinus Torvalds err = remap_pud_range(mm, pgd, addr, next, 23741da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 23751da177e4SLinus Torvalds if (err) 23761da177e4SLinus Torvalds break; 23771da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 23782ab64037Svenkatesh.pallipadi@intel.com 23792ab64037Svenkatesh.pallipadi@intel.com if (err) 23805180da41SSuresh Siddha untrack_pfn(vma, pfn, PAGE_ALIGN(size)); 23812ab64037Svenkatesh.pallipadi@intel.com 23821da177e4SLinus Torvalds return err; 23831da177e4SLinus Torvalds } 23841da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 23851da177e4SLinus Torvalds 2386b4cbb197SLinus Torvalds /** 2387b4cbb197SLinus Torvalds * vm_iomap_memory - remap memory to userspace 2388b4cbb197SLinus Torvalds * @vma: user vma to map to 2389b4cbb197SLinus Torvalds * @start: start of area 2390b4cbb197SLinus Torvalds * @len: size of area 2391b4cbb197SLinus Torvalds * 2392b4cbb197SLinus Torvalds * This is a simplified io_remap_pfn_range() for common driver use. The 2393b4cbb197SLinus Torvalds * driver just needs to give us the physical memory range to be mapped, 2394b4cbb197SLinus Torvalds * we'll figure out the rest from the vma information. 2395b4cbb197SLinus Torvalds * 2396b4cbb197SLinus Torvalds * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get 2397b4cbb197SLinus Torvalds * whatever write-combining details or similar. 2398b4cbb197SLinus Torvalds */ 2399b4cbb197SLinus Torvalds int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) 2400b4cbb197SLinus Torvalds { 2401b4cbb197SLinus Torvalds unsigned long vm_len, pfn, pages; 2402b4cbb197SLinus Torvalds 2403b4cbb197SLinus Torvalds /* Check that the physical memory area passed in looks valid */ 2404b4cbb197SLinus Torvalds if (start + len < start) 2405b4cbb197SLinus Torvalds return -EINVAL; 2406b4cbb197SLinus Torvalds /* 2407b4cbb197SLinus Torvalds * You *really* shouldn't map things that aren't page-aligned, 2408b4cbb197SLinus Torvalds * but we've historically allowed it because IO memory might 2409b4cbb197SLinus Torvalds * just have smaller alignment. 2410b4cbb197SLinus Torvalds */ 2411b4cbb197SLinus Torvalds len += start & ~PAGE_MASK; 2412b4cbb197SLinus Torvalds pfn = start >> PAGE_SHIFT; 2413b4cbb197SLinus Torvalds pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; 2414b4cbb197SLinus Torvalds if (pfn + pages < pfn) 2415b4cbb197SLinus Torvalds return -EINVAL; 2416b4cbb197SLinus Torvalds 2417b4cbb197SLinus Torvalds /* We start the mapping 'vm_pgoff' pages into the area */ 2418b4cbb197SLinus Torvalds if (vma->vm_pgoff > pages) 2419b4cbb197SLinus Torvalds return -EINVAL; 2420b4cbb197SLinus Torvalds pfn += vma->vm_pgoff; 2421b4cbb197SLinus Torvalds pages -= vma->vm_pgoff; 2422b4cbb197SLinus Torvalds 2423b4cbb197SLinus Torvalds /* Can we fit all of the mapping? */ 2424b4cbb197SLinus Torvalds vm_len = vma->vm_end - vma->vm_start; 2425b4cbb197SLinus Torvalds if (vm_len >> PAGE_SHIFT > pages) 2426b4cbb197SLinus Torvalds return -EINVAL; 2427b4cbb197SLinus Torvalds 2428b4cbb197SLinus Torvalds /* Ok, let it rip */ 2429b4cbb197SLinus Torvalds return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); 2430b4cbb197SLinus Torvalds } 2431b4cbb197SLinus Torvalds EXPORT_SYMBOL(vm_iomap_memory); 2432b4cbb197SLinus Torvalds 2433aee16b3cSJeremy Fitzhardinge static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 2434aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2435aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2436aee16b3cSJeremy Fitzhardinge { 2437aee16b3cSJeremy Fitzhardinge pte_t *pte; 2438aee16b3cSJeremy Fitzhardinge int err; 24392f569afdSMartin Schwidefsky pgtable_t token; 244094909914SBorislav Petkov spinlock_t *uninitialized_var(ptl); 2441aee16b3cSJeremy Fitzhardinge 2442aee16b3cSJeremy Fitzhardinge pte = (mm == &init_mm) ? 2443aee16b3cSJeremy Fitzhardinge pte_alloc_kernel(pmd, addr) : 2444aee16b3cSJeremy Fitzhardinge pte_alloc_map_lock(mm, pmd, addr, &ptl); 2445aee16b3cSJeremy Fitzhardinge if (!pte) 2446aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2447aee16b3cSJeremy Fitzhardinge 2448aee16b3cSJeremy Fitzhardinge BUG_ON(pmd_huge(*pmd)); 2449aee16b3cSJeremy Fitzhardinge 245038e0edb1SJeremy Fitzhardinge arch_enter_lazy_mmu_mode(); 245138e0edb1SJeremy Fitzhardinge 24522f569afdSMartin Schwidefsky token = pmd_pgtable(*pmd); 2453aee16b3cSJeremy Fitzhardinge 2454aee16b3cSJeremy Fitzhardinge do { 2455c36987e2SDaisuke Nishimura err = fn(pte++, token, addr, data); 2456aee16b3cSJeremy Fitzhardinge if (err) 2457aee16b3cSJeremy Fitzhardinge break; 2458c36987e2SDaisuke Nishimura } while (addr += PAGE_SIZE, addr != end); 2459aee16b3cSJeremy Fitzhardinge 246038e0edb1SJeremy Fitzhardinge arch_leave_lazy_mmu_mode(); 246138e0edb1SJeremy Fitzhardinge 2462aee16b3cSJeremy Fitzhardinge if (mm != &init_mm) 2463aee16b3cSJeremy Fitzhardinge pte_unmap_unlock(pte-1, ptl); 2464aee16b3cSJeremy Fitzhardinge return err; 2465aee16b3cSJeremy Fitzhardinge } 2466aee16b3cSJeremy Fitzhardinge 2467aee16b3cSJeremy Fitzhardinge static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 2468aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2469aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2470aee16b3cSJeremy Fitzhardinge { 2471aee16b3cSJeremy Fitzhardinge pmd_t *pmd; 2472aee16b3cSJeremy Fitzhardinge unsigned long next; 2473aee16b3cSJeremy Fitzhardinge int err; 2474aee16b3cSJeremy Fitzhardinge 2475ceb86879SAndi Kleen BUG_ON(pud_huge(*pud)); 2476ceb86879SAndi Kleen 2477aee16b3cSJeremy Fitzhardinge pmd = pmd_alloc(mm, pud, addr); 2478aee16b3cSJeremy Fitzhardinge if (!pmd) 2479aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2480aee16b3cSJeremy Fitzhardinge do { 2481aee16b3cSJeremy Fitzhardinge next = pmd_addr_end(addr, end); 2482aee16b3cSJeremy Fitzhardinge err = apply_to_pte_range(mm, pmd, addr, next, fn, data); 2483aee16b3cSJeremy Fitzhardinge if (err) 2484aee16b3cSJeremy Fitzhardinge break; 2485aee16b3cSJeremy Fitzhardinge } while (pmd++, addr = next, addr != end); 2486aee16b3cSJeremy Fitzhardinge return err; 2487aee16b3cSJeremy Fitzhardinge } 2488aee16b3cSJeremy Fitzhardinge 2489aee16b3cSJeremy Fitzhardinge static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, 2490aee16b3cSJeremy Fitzhardinge unsigned long addr, unsigned long end, 2491aee16b3cSJeremy Fitzhardinge pte_fn_t fn, void *data) 2492aee16b3cSJeremy Fitzhardinge { 2493aee16b3cSJeremy Fitzhardinge pud_t *pud; 2494aee16b3cSJeremy Fitzhardinge unsigned long next; 2495aee16b3cSJeremy Fitzhardinge int err; 2496aee16b3cSJeremy Fitzhardinge 2497aee16b3cSJeremy Fitzhardinge pud = pud_alloc(mm, pgd, addr); 2498aee16b3cSJeremy Fitzhardinge if (!pud) 2499aee16b3cSJeremy Fitzhardinge return -ENOMEM; 2500aee16b3cSJeremy Fitzhardinge do { 2501aee16b3cSJeremy Fitzhardinge next = pud_addr_end(addr, end); 2502aee16b3cSJeremy Fitzhardinge err = apply_to_pmd_range(mm, pud, addr, next, fn, data); 2503aee16b3cSJeremy Fitzhardinge if (err) 2504aee16b3cSJeremy Fitzhardinge break; 2505aee16b3cSJeremy Fitzhardinge } while (pud++, addr = next, addr != end); 2506aee16b3cSJeremy Fitzhardinge return err; 2507aee16b3cSJeremy Fitzhardinge } 2508aee16b3cSJeremy Fitzhardinge 2509aee16b3cSJeremy Fitzhardinge /* 2510aee16b3cSJeremy Fitzhardinge * Scan a region of virtual memory, filling in page tables as necessary 2511aee16b3cSJeremy Fitzhardinge * and calling a provided function on each leaf page table. 2512aee16b3cSJeremy Fitzhardinge */ 2513aee16b3cSJeremy Fitzhardinge int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 2514aee16b3cSJeremy Fitzhardinge unsigned long size, pte_fn_t fn, void *data) 2515aee16b3cSJeremy Fitzhardinge { 2516aee16b3cSJeremy Fitzhardinge pgd_t *pgd; 2517aee16b3cSJeremy Fitzhardinge unsigned long next; 251857250a5bSJeremy Fitzhardinge unsigned long end = addr + size; 2519aee16b3cSJeremy Fitzhardinge int err; 2520aee16b3cSJeremy Fitzhardinge 2521aee16b3cSJeremy Fitzhardinge BUG_ON(addr >= end); 2522aee16b3cSJeremy Fitzhardinge pgd = pgd_offset(mm, addr); 2523aee16b3cSJeremy Fitzhardinge do { 2524aee16b3cSJeremy Fitzhardinge next = pgd_addr_end(addr, end); 2525aee16b3cSJeremy Fitzhardinge err = apply_to_pud_range(mm, pgd, addr, next, fn, data); 2526aee16b3cSJeremy Fitzhardinge if (err) 2527aee16b3cSJeremy Fitzhardinge break; 2528aee16b3cSJeremy Fitzhardinge } while (pgd++, addr = next, addr != end); 252957250a5bSJeremy Fitzhardinge 2530aee16b3cSJeremy Fitzhardinge return err; 2531aee16b3cSJeremy Fitzhardinge } 2532aee16b3cSJeremy Fitzhardinge EXPORT_SYMBOL_GPL(apply_to_page_range); 2533aee16b3cSJeremy Fitzhardinge 25341da177e4SLinus Torvalds /* 25358f4e2101SHugh Dickins * handle_pte_fault chooses page fault handler according to an entry 25368f4e2101SHugh Dickins * which was read non-atomically. Before making any commitment, on 25378f4e2101SHugh Dickins * those architectures or configurations (e.g. i386 with PAE) which 2538a335b2e1SRyota Ozaki * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault 25398f4e2101SHugh Dickins * must check under lock before unmapping the pte and proceeding 25408f4e2101SHugh Dickins * (but do_wp_page is only called after already making such a check; 2541a335b2e1SRyota Ozaki * and do_anonymous_page can safely check later on). 25428f4e2101SHugh Dickins */ 25434c21e2f2SHugh Dickins static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 25448f4e2101SHugh Dickins pte_t *page_table, pte_t orig_pte) 25458f4e2101SHugh Dickins { 25468f4e2101SHugh Dickins int same = 1; 25478f4e2101SHugh Dickins #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) 25488f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 25494c21e2f2SHugh Dickins spinlock_t *ptl = pte_lockptr(mm, pmd); 25504c21e2f2SHugh Dickins spin_lock(ptl); 25518f4e2101SHugh Dickins same = pte_same(*page_table, orig_pte); 25524c21e2f2SHugh Dickins spin_unlock(ptl); 25538f4e2101SHugh Dickins } 25548f4e2101SHugh Dickins #endif 25558f4e2101SHugh Dickins pte_unmap(page_table); 25568f4e2101SHugh Dickins return same; 25578f4e2101SHugh Dickins } 25588f4e2101SHugh Dickins 25599de455b2SAtsushi Nemoto static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) 25606aab341eSLinus Torvalds { 25616aab341eSLinus Torvalds /* 25626aab341eSLinus Torvalds * If the source page was a PFN mapping, we don't have 25636aab341eSLinus Torvalds * a "struct page" for it. We do a best-effort copy by 25646aab341eSLinus Torvalds * just copying from the original user address. If that 25656aab341eSLinus Torvalds * fails, we just zero-fill it. Live with it. 25666aab341eSLinus Torvalds */ 25676aab341eSLinus Torvalds if (unlikely(!src)) { 25689b04c5feSCong Wang void *kaddr = kmap_atomic(dst); 25695d2a2dbbSLinus Torvalds void __user *uaddr = (void __user *)(va & PAGE_MASK); 25705d2a2dbbSLinus Torvalds 25715d2a2dbbSLinus Torvalds /* 25725d2a2dbbSLinus Torvalds * This really shouldn't fail, because the page is there 25735d2a2dbbSLinus Torvalds * in the page tables. But it might just be unreadable, 25745d2a2dbbSLinus Torvalds * in which case we just give up and fill the result with 25755d2a2dbbSLinus Torvalds * zeroes. 25765d2a2dbbSLinus Torvalds */ 25775d2a2dbbSLinus Torvalds if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) 25783ecb01dfSJan Beulich clear_page(kaddr); 25799b04c5feSCong Wang kunmap_atomic(kaddr); 2580c4ec7b0dSDmitriy Monakhov flush_dcache_page(dst); 25810ed361deSNick Piggin } else 25829de455b2SAtsushi Nemoto copy_user_highpage(dst, src, va, vma); 25836aab341eSLinus Torvalds } 25846aab341eSLinus Torvalds 25851da177e4SLinus Torvalds /* 25861da177e4SLinus Torvalds * This routine handles present pages, when users try to write 25871da177e4SLinus Torvalds * to a shared page. It is done by copying the page to a new address 25881da177e4SLinus Torvalds * and decrementing the shared-page counter for the old page. 25891da177e4SLinus Torvalds * 25901da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 25911da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 25921da177e4SLinus Torvalds * Thus we can safely just mark it writable once we've done any necessary 25931da177e4SLinus Torvalds * COW. 25941da177e4SLinus Torvalds * 25951da177e4SLinus Torvalds * We also mark the page dirty at this point even though the page will 25961da177e4SLinus Torvalds * change only once the write actually happens. This avoids a few races, 25971da177e4SLinus Torvalds * and potentially makes it more efficient. 25981da177e4SLinus Torvalds * 25998f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 26008f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 26018f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 26021da177e4SLinus Torvalds */ 26031da177e4SLinus Torvalds static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 260465500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 26058f4e2101SHugh Dickins spinlock_t *ptl, pte_t orig_pte) 2606e6219ec8SNamhyung Kim __releases(ptl) 26071da177e4SLinus Torvalds { 26082ec74c3eSSagi Grimberg struct page *old_page, *new_page = NULL; 26091da177e4SLinus Torvalds pte_t entry; 2610b009c024SMichel Lespinasse int ret = 0; 2611a200ee18SPeter Zijlstra int page_mkwrite = 0; 2612d08b3851SPeter Zijlstra struct page *dirty_page = NULL; 26131756954cSDavid Rientjes unsigned long mmun_start = 0; /* For mmu_notifiers */ 26141756954cSDavid Rientjes unsigned long mmun_end = 0; /* For mmu_notifiers */ 26151da177e4SLinus Torvalds 26166aab341eSLinus Torvalds old_page = vm_normal_page(vma, address, orig_pte); 2617251b97f5SPeter Zijlstra if (!old_page) { 2618251b97f5SPeter Zijlstra /* 2619251b97f5SPeter Zijlstra * VM_MIXEDMAP !pfn_valid() case 2620251b97f5SPeter Zijlstra * 2621251b97f5SPeter Zijlstra * We should not cow pages in a shared writeable mapping. 2622251b97f5SPeter Zijlstra * Just mark the pages writable as we can't do any dirty 2623251b97f5SPeter Zijlstra * accounting on raw pfn maps. 2624251b97f5SPeter Zijlstra */ 2625251b97f5SPeter Zijlstra if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 2626251b97f5SPeter Zijlstra (VM_WRITE|VM_SHARED)) 2627251b97f5SPeter Zijlstra goto reuse; 2628920fc356SHugh Dickins goto gotten; 2629251b97f5SPeter Zijlstra } 26301da177e4SLinus Torvalds 2631d08b3851SPeter Zijlstra /* 2632ee6a6457SPeter Zijlstra * Take out anonymous pages first, anonymous shared vmas are 2633ee6a6457SPeter Zijlstra * not dirty accountable. 2634d08b3851SPeter Zijlstra */ 26359a840895SHugh Dickins if (PageAnon(old_page) && !PageKsm(old_page)) { 2636ab967d86SHugh Dickins if (!trylock_page(old_page)) { 2637ab967d86SHugh Dickins page_cache_get(old_page); 2638ab967d86SHugh Dickins pte_unmap_unlock(page_table, ptl); 2639ab967d86SHugh Dickins lock_page(old_page); 2640ab967d86SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, 2641ab967d86SHugh Dickins &ptl); 2642ab967d86SHugh Dickins if (!pte_same(*page_table, orig_pte)) { 2643ab967d86SHugh Dickins unlock_page(old_page); 2644ab967d86SHugh Dickins goto unlock; 2645ab967d86SHugh Dickins } 2646ab967d86SHugh Dickins page_cache_release(old_page); 2647ab967d86SHugh Dickins } 2648b009c024SMichel Lespinasse if (reuse_swap_page(old_page)) { 2649c44b6743SRik van Riel /* 2650c44b6743SRik van Riel * The page is all ours. Move it to our anon_vma so 2651c44b6743SRik van Riel * the rmap code will not search our parent or siblings. 2652c44b6743SRik van Riel * Protected against the rmap code by the page lock. 2653c44b6743SRik van Riel */ 2654c44b6743SRik van Riel page_move_anon_rmap(old_page, vma, address); 2655ee6a6457SPeter Zijlstra unlock_page(old_page); 2656b009c024SMichel Lespinasse goto reuse; 2657b009c024SMichel Lespinasse } 2658b009c024SMichel Lespinasse unlock_page(old_page); 2659ee6a6457SPeter Zijlstra } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 2660d08b3851SPeter Zijlstra (VM_WRITE|VM_SHARED))) { 2661ee6a6457SPeter Zijlstra /* 2662ee6a6457SPeter Zijlstra * Only catch write-faults on shared writable pages, 2663ee6a6457SPeter Zijlstra * read-only shared pages can get COWed by 2664ee6a6457SPeter Zijlstra * get_user_pages(.write=1, .force=1). 2665ee6a6457SPeter Zijlstra */ 26669637a5efSDavid Howells if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 2667c2ec175cSNick Piggin struct vm_fault vmf; 2668c2ec175cSNick Piggin int tmp; 2669c2ec175cSNick Piggin 2670c2ec175cSNick Piggin vmf.virtual_address = (void __user *)(address & 2671c2ec175cSNick Piggin PAGE_MASK); 2672c2ec175cSNick Piggin vmf.pgoff = old_page->index; 2673c2ec175cSNick Piggin vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 2674c2ec175cSNick Piggin vmf.page = old_page; 2675c2ec175cSNick Piggin 26769637a5efSDavid Howells /* 26779637a5efSDavid Howells * Notify the address space that the page is about to 26789637a5efSDavid Howells * become writable so that it can prohibit this or wait 26799637a5efSDavid Howells * for the page to get into an appropriate state. 26809637a5efSDavid Howells * 26819637a5efSDavid Howells * We do this without the lock held, so that it can 26829637a5efSDavid Howells * sleep if it needs to. 26839637a5efSDavid Howells */ 26849637a5efSDavid Howells page_cache_get(old_page); 26859637a5efSDavid Howells pte_unmap_unlock(page_table, ptl); 26869637a5efSDavid Howells 2687c2ec175cSNick Piggin tmp = vma->vm_ops->page_mkwrite(vma, &vmf); 2688c2ec175cSNick Piggin if (unlikely(tmp & 2689c2ec175cSNick Piggin (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 2690c2ec175cSNick Piggin ret = tmp; 26919637a5efSDavid Howells goto unwritable_page; 2692c2ec175cSNick Piggin } 2693b827e496SNick Piggin if (unlikely(!(tmp & VM_FAULT_LOCKED))) { 2694b827e496SNick Piggin lock_page(old_page); 2695b827e496SNick Piggin if (!old_page->mapping) { 2696b827e496SNick Piggin ret = 0; /* retry the fault */ 2697b827e496SNick Piggin unlock_page(old_page); 2698b827e496SNick Piggin goto unwritable_page; 2699b827e496SNick Piggin } 2700b827e496SNick Piggin } else 2701b827e496SNick Piggin VM_BUG_ON(!PageLocked(old_page)); 27029637a5efSDavid Howells 27039637a5efSDavid Howells /* 27049637a5efSDavid Howells * Since we dropped the lock we need to revalidate 27059637a5efSDavid Howells * the PTE as someone else may have changed it. If 27069637a5efSDavid Howells * they did, we just return, as we can count on the 27079637a5efSDavid Howells * MMU to tell us if they didn't also make it writable. 27089637a5efSDavid Howells */ 27099637a5efSDavid Howells page_table = pte_offset_map_lock(mm, pmd, address, 27109637a5efSDavid Howells &ptl); 2711b827e496SNick Piggin if (!pte_same(*page_table, orig_pte)) { 2712b827e496SNick Piggin unlock_page(old_page); 27139637a5efSDavid Howells goto unlock; 2714b827e496SNick Piggin } 2715a200ee18SPeter Zijlstra 2716a200ee18SPeter Zijlstra page_mkwrite = 1; 27179637a5efSDavid Howells } 2718d08b3851SPeter Zijlstra dirty_page = old_page; 2719d08b3851SPeter Zijlstra get_page(dirty_page); 27209637a5efSDavid Howells 2721251b97f5SPeter Zijlstra reuse: 2722eca35133SBen Collins flush_cache_page(vma, address, pte_pfn(orig_pte)); 272365500d23SHugh Dickins entry = pte_mkyoung(orig_pte); 272465500d23SHugh Dickins entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2725954ffcb3SKAMEZAWA Hiroyuki if (ptep_set_access_flags(vma, address, page_table, entry,1)) 27264b3073e1SRussell King update_mmu_cache(vma, address, page_table); 272772ddc8f7SMichel Lespinasse pte_unmap_unlock(page_table, ptl); 272865500d23SHugh Dickins ret |= VM_FAULT_WRITE; 272972ddc8f7SMichel Lespinasse 273072ddc8f7SMichel Lespinasse if (!dirty_page) 273172ddc8f7SMichel Lespinasse return ret; 273272ddc8f7SMichel Lespinasse 273372ddc8f7SMichel Lespinasse /* 273472ddc8f7SMichel Lespinasse * Yes, Virginia, this is actually required to prevent a race 273572ddc8f7SMichel Lespinasse * with clear_page_dirty_for_io() from clearing the page dirty 273672ddc8f7SMichel Lespinasse * bit after it clear all dirty ptes, but before a racing 273772ddc8f7SMichel Lespinasse * do_wp_page installs a dirty pte. 273872ddc8f7SMichel Lespinasse * 2739a335b2e1SRyota Ozaki * __do_fault is protected similarly. 274072ddc8f7SMichel Lespinasse */ 274172ddc8f7SMichel Lespinasse if (!page_mkwrite) { 274272ddc8f7SMichel Lespinasse wait_on_page_locked(dirty_page); 274372ddc8f7SMichel Lespinasse set_page_dirty_balance(dirty_page, page_mkwrite); 274441c4d25fSJan Kara /* file_update_time outside page_lock */ 274541c4d25fSJan Kara if (vma->vm_file) 274641c4d25fSJan Kara file_update_time(vma->vm_file); 274772ddc8f7SMichel Lespinasse } 274872ddc8f7SMichel Lespinasse put_page(dirty_page); 274972ddc8f7SMichel Lespinasse if (page_mkwrite) { 275072ddc8f7SMichel Lespinasse struct address_space *mapping = dirty_page->mapping; 275172ddc8f7SMichel Lespinasse 275272ddc8f7SMichel Lespinasse set_page_dirty(dirty_page); 275372ddc8f7SMichel Lespinasse unlock_page(dirty_page); 275472ddc8f7SMichel Lespinasse page_cache_release(dirty_page); 275572ddc8f7SMichel Lespinasse if (mapping) { 275672ddc8f7SMichel Lespinasse /* 275772ddc8f7SMichel Lespinasse * Some device drivers do not set page.mapping 275872ddc8f7SMichel Lespinasse * but still dirty their pages 275972ddc8f7SMichel Lespinasse */ 276072ddc8f7SMichel Lespinasse balance_dirty_pages_ratelimited(mapping); 276172ddc8f7SMichel Lespinasse } 276272ddc8f7SMichel Lespinasse } 276372ddc8f7SMichel Lespinasse 276472ddc8f7SMichel Lespinasse return ret; 27651da177e4SLinus Torvalds } 27661da177e4SLinus Torvalds 27671da177e4SLinus Torvalds /* 27681da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 27691da177e4SLinus Torvalds */ 27701da177e4SLinus Torvalds page_cache_get(old_page); 2771920fc356SHugh Dickins gotten: 27728f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 27731da177e4SLinus Torvalds 27741da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 277565500d23SHugh Dickins goto oom; 2776a13ea5b7SHugh Dickins 277762eede62SHugh Dickins if (is_zero_pfn(pte_pfn(orig_pte))) { 2778a13ea5b7SHugh Dickins new_page = alloc_zeroed_user_highpage_movable(vma, address); 2779a13ea5b7SHugh Dickins if (!new_page) 2780a13ea5b7SHugh Dickins goto oom; 2781a13ea5b7SHugh Dickins } else { 2782769848c0SMel Gorman new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); 27831da177e4SLinus Torvalds if (!new_page) 278465500d23SHugh Dickins goto oom; 2785a13ea5b7SHugh Dickins cow_user_page(new_page, old_page, address, vma); 2786a13ea5b7SHugh Dickins } 2787a13ea5b7SHugh Dickins __SetPageUptodate(new_page); 2788a13ea5b7SHugh Dickins 27892c26fdd7SKAMEZAWA Hiroyuki if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) 27908a9f3ccdSBalbir Singh goto oom_free_new; 27918a9f3ccdSBalbir Singh 27926bdb913fSHaggai Eran mmun_start = address & PAGE_MASK; 27931756954cSDavid Rientjes mmun_end = mmun_start + PAGE_SIZE; 27946bdb913fSHaggai Eran mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 27956bdb913fSHaggai Eran 27961da177e4SLinus Torvalds /* 27971da177e4SLinus Torvalds * Re-check the pte - we dropped the lock 27981da177e4SLinus Torvalds */ 27998f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 280065500d23SHugh Dickins if (likely(pte_same(*page_table, orig_pte))) { 2801920fc356SHugh Dickins if (old_page) { 28024294621fSHugh Dickins if (!PageAnon(old_page)) { 280334e55232SKAMEZAWA Hiroyuki dec_mm_counter_fast(mm, MM_FILEPAGES); 280434e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_ANONPAGES); 28054294621fSHugh Dickins } 2806920fc356SHugh Dickins } else 280734e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_ANONPAGES); 2808eca35133SBen Collins flush_cache_page(vma, address, pte_pfn(orig_pte)); 280965500d23SHugh Dickins entry = mk_pte(new_page, vma->vm_page_prot); 281065500d23SHugh Dickins entry = maybe_mkwrite(pte_mkdirty(entry), vma); 28114ce072f1SSiddha, Suresh B /* 28124ce072f1SSiddha, Suresh B * Clear the pte entry and flush it first, before updating the 28134ce072f1SSiddha, Suresh B * pte with the new entry. This will avoid a race condition 28144ce072f1SSiddha, Suresh B * seen in the presence of one thread doing SMC and another 28154ce072f1SSiddha, Suresh B * thread doing COW. 28164ce072f1SSiddha, Suresh B */ 2817828502d3SIzik Eidus ptep_clear_flush(vma, address, page_table); 28189617d95eSNick Piggin page_add_new_anon_rmap(new_page, vma, address); 2819828502d3SIzik Eidus /* 2820828502d3SIzik Eidus * We call the notify macro here because, when using secondary 2821828502d3SIzik Eidus * mmu page tables (such as kvm shadow page tables), we want the 2822828502d3SIzik Eidus * new page to be mapped directly into the secondary page table. 2823828502d3SIzik Eidus */ 2824828502d3SIzik Eidus set_pte_at_notify(mm, address, page_table, entry); 28254b3073e1SRussell King update_mmu_cache(vma, address, page_table); 2826945754a1SNick Piggin if (old_page) { 2827945754a1SNick Piggin /* 2828945754a1SNick Piggin * Only after switching the pte to the new page may 2829945754a1SNick Piggin * we remove the mapcount here. Otherwise another 2830945754a1SNick Piggin * process may come and find the rmap count decremented 2831945754a1SNick Piggin * before the pte is switched to the new page, and 2832945754a1SNick Piggin * "reuse" the old page writing into it while our pte 2833945754a1SNick Piggin * here still points into it and can be read by other 2834945754a1SNick Piggin * threads. 2835945754a1SNick Piggin * 2836945754a1SNick Piggin * The critical issue is to order this 2837945754a1SNick Piggin * page_remove_rmap with the ptp_clear_flush above. 2838945754a1SNick Piggin * Those stores are ordered by (if nothing else,) 2839945754a1SNick Piggin * the barrier present in the atomic_add_negative 2840945754a1SNick Piggin * in page_remove_rmap. 2841945754a1SNick Piggin * 2842945754a1SNick Piggin * Then the TLB flush in ptep_clear_flush ensures that 2843945754a1SNick Piggin * no process can access the old page before the 2844945754a1SNick Piggin * decremented mapcount is visible. And the old page 2845945754a1SNick Piggin * cannot be reused until after the decremented 2846945754a1SNick Piggin * mapcount is visible. So transitively, TLBs to 2847945754a1SNick Piggin * old page will be flushed before it can be reused. 2848945754a1SNick Piggin */ 2849edc315fdSHugh Dickins page_remove_rmap(old_page); 2850945754a1SNick Piggin } 2851945754a1SNick Piggin 28521da177e4SLinus Torvalds /* Free the old page.. */ 28531da177e4SLinus Torvalds new_page = old_page; 2854f33ea7f4SNick Piggin ret |= VM_FAULT_WRITE; 28558a9f3ccdSBalbir Singh } else 28568a9f3ccdSBalbir Singh mem_cgroup_uncharge_page(new_page); 28578a9f3ccdSBalbir Singh 28586bdb913fSHaggai Eran if (new_page) 28596bdb913fSHaggai Eran page_cache_release(new_page); 286065500d23SHugh Dickins unlock: 28618f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 28621756954cSDavid Rientjes if (mmun_end > mmun_start) 28636bdb913fSHaggai Eran mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2864e15f8c01SMichel Lespinasse if (old_page) { 2865e15f8c01SMichel Lespinasse /* 2866e15f8c01SMichel Lespinasse * Don't let another task, with possibly unlocked vma, 2867e15f8c01SMichel Lespinasse * keep the mlocked page. 2868e15f8c01SMichel Lespinasse */ 2869e15f8c01SMichel Lespinasse if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) { 2870e15f8c01SMichel Lespinasse lock_page(old_page); /* LRU manipulation */ 2871e15f8c01SMichel Lespinasse munlock_vma_page(old_page); 2872e15f8c01SMichel Lespinasse unlock_page(old_page); 2873e15f8c01SMichel Lespinasse } 2874e15f8c01SMichel Lespinasse page_cache_release(old_page); 2875e15f8c01SMichel Lespinasse } 2876f33ea7f4SNick Piggin return ret; 28778a9f3ccdSBalbir Singh oom_free_new: 28786dbf6d3bSHugh Dickins page_cache_release(new_page); 287965500d23SHugh Dickins oom: 288066521d5aSDominik Dingel if (old_page) 28811da177e4SLinus Torvalds page_cache_release(old_page); 28821da177e4SLinus Torvalds return VM_FAULT_OOM; 28839637a5efSDavid Howells 28849637a5efSDavid Howells unwritable_page: 28859637a5efSDavid Howells page_cache_release(old_page); 2886c2ec175cSNick Piggin return ret; 28871da177e4SLinus Torvalds } 28881da177e4SLinus Torvalds 288997a89413SPeter Zijlstra static void unmap_mapping_range_vma(struct vm_area_struct *vma, 28901da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 28911da177e4SLinus Torvalds struct zap_details *details) 28921da177e4SLinus Torvalds { 2893f5cc4eefSAl Viro zap_page_range_single(vma, start_addr, end_addr - start_addr, details); 28941da177e4SLinus Torvalds } 28951da177e4SLinus Torvalds 28966b2dbba8SMichel Lespinasse static inline void unmap_mapping_range_tree(struct rb_root *root, 28971da177e4SLinus Torvalds struct zap_details *details) 28981da177e4SLinus Torvalds { 28991da177e4SLinus Torvalds struct vm_area_struct *vma; 29001da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 29011da177e4SLinus Torvalds 29026b2dbba8SMichel Lespinasse vma_interval_tree_foreach(vma, root, 29031da177e4SLinus Torvalds details->first_index, details->last_index) { 29041da177e4SLinus Torvalds 29051da177e4SLinus Torvalds vba = vma->vm_pgoff; 2906d6e93217SLibin vea = vba + vma_pages(vma) - 1; 29071da177e4SLinus Torvalds /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 29081da177e4SLinus Torvalds zba = details->first_index; 29091da177e4SLinus Torvalds if (zba < vba) 29101da177e4SLinus Torvalds zba = vba; 29111da177e4SLinus Torvalds zea = details->last_index; 29121da177e4SLinus Torvalds if (zea > vea) 29131da177e4SLinus Torvalds zea = vea; 29141da177e4SLinus Torvalds 291597a89413SPeter Zijlstra unmap_mapping_range_vma(vma, 29161da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 29171da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 291897a89413SPeter Zijlstra details); 29191da177e4SLinus Torvalds } 29201da177e4SLinus Torvalds } 29211da177e4SLinus Torvalds 29221da177e4SLinus Torvalds static inline void unmap_mapping_range_list(struct list_head *head, 29231da177e4SLinus Torvalds struct zap_details *details) 29241da177e4SLinus Torvalds { 29251da177e4SLinus Torvalds struct vm_area_struct *vma; 29261da177e4SLinus Torvalds 29271da177e4SLinus Torvalds /* 29281da177e4SLinus Torvalds * In nonlinear VMAs there is no correspondence between virtual address 29291da177e4SLinus Torvalds * offset and file offset. So we must perform an exhaustive search 29301da177e4SLinus Torvalds * across *all* the pages in each nonlinear VMA, not just the pages 29311da177e4SLinus Torvalds * whose virtual address lies outside the file truncation point. 29321da177e4SLinus Torvalds */ 29336b2dbba8SMichel Lespinasse list_for_each_entry(vma, head, shared.nonlinear) { 29341da177e4SLinus Torvalds details->nonlinear_vma = vma; 293597a89413SPeter Zijlstra unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details); 29361da177e4SLinus Torvalds } 29371da177e4SLinus Torvalds } 29381da177e4SLinus Torvalds 29391da177e4SLinus Torvalds /** 294072fd4a35SRobert P. J. Day * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file. 29413d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 29421da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 29431da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 294425d9e2d1Snpiggin@suse.de * boundary. Note that this is different from truncate_pagecache(), which 29451da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 29461da177e4SLinus Torvalds * partial pages. 29471da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 29481da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 29491da177e4SLinus Torvalds * end of the file. 29501da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 29511da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 29521da177e4SLinus Torvalds */ 29531da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 29541da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 29551da177e4SLinus Torvalds { 29561da177e4SLinus Torvalds struct zap_details details; 29571da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 29581da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 29591da177e4SLinus Torvalds 29601da177e4SLinus Torvalds /* Check for overflow. */ 29611da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 29621da177e4SLinus Torvalds long long holeend = 29631da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 29641da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 29651da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 29661da177e4SLinus Torvalds } 29671da177e4SLinus Torvalds 29681da177e4SLinus Torvalds details.check_mapping = even_cows? NULL: mapping; 29691da177e4SLinus Torvalds details.nonlinear_vma = NULL; 29701da177e4SLinus Torvalds details.first_index = hba; 29711da177e4SLinus Torvalds details.last_index = hba + hlen - 1; 29721da177e4SLinus Torvalds if (details.last_index < details.first_index) 29731da177e4SLinus Torvalds details.last_index = ULONG_MAX; 29741da177e4SLinus Torvalds 297597a89413SPeter Zijlstra 29763d48ae45SPeter Zijlstra mutex_lock(&mapping->i_mmap_mutex); 29776b2dbba8SMichel Lespinasse if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap))) 29781da177e4SLinus Torvalds unmap_mapping_range_tree(&mapping->i_mmap, &details); 29791da177e4SLinus Torvalds if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 29801da177e4SLinus Torvalds unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 29813d48ae45SPeter Zijlstra mutex_unlock(&mapping->i_mmap_mutex); 29821da177e4SLinus Torvalds } 29831da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 29841da177e4SLinus Torvalds 29851da177e4SLinus Torvalds /* 29868f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 29878f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 29888f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 29891da177e4SLinus Torvalds */ 299065500d23SHugh Dickins static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 299165500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 299230c9f3a9SLinus Torvalds unsigned int flags, pte_t orig_pte) 29931da177e4SLinus Torvalds { 29948f4e2101SHugh Dickins spinlock_t *ptl; 299556f31801SHugh Dickins struct page *page, *swapcache; 299665500d23SHugh Dickins swp_entry_t entry; 29971da177e4SLinus Torvalds pte_t pte; 2998d065bd81SMichel Lespinasse int locked; 299956039efaSKAMEZAWA Hiroyuki struct mem_cgroup *ptr; 3000ad8c2ee8SRik van Riel int exclusive = 0; 300183c54070SNick Piggin int ret = 0; 30021da177e4SLinus Torvalds 30034c21e2f2SHugh Dickins if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 30048f4e2101SHugh Dickins goto out; 300565500d23SHugh Dickins 300665500d23SHugh Dickins entry = pte_to_swp_entry(orig_pte); 3007d1737fdbSAndi Kleen if (unlikely(non_swap_entry(entry))) { 30080697212aSChristoph Lameter if (is_migration_entry(entry)) { 30090697212aSChristoph Lameter migration_entry_wait(mm, pmd, address); 3010d1737fdbSAndi Kleen } else if (is_hwpoison_entry(entry)) { 3011d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3012d1737fdbSAndi Kleen } else { 3013d1737fdbSAndi Kleen print_bad_pte(vma, address, orig_pte, NULL); 3014d99be1a8SHugh Dickins ret = VM_FAULT_SIGBUS; 3015d1737fdbSAndi Kleen } 30160697212aSChristoph Lameter goto out; 30170697212aSChristoph Lameter } 30180ff92245SShailabh Nagar delayacct_set_flag(DELAYACCT_PF_SWAPIN); 30191da177e4SLinus Torvalds page = lookup_swap_cache(entry); 30201da177e4SLinus Torvalds if (!page) { 302102098feaSHugh Dickins page = swapin_readahead(entry, 302202098feaSHugh Dickins GFP_HIGHUSER_MOVABLE, vma, address); 30231da177e4SLinus Torvalds if (!page) { 30241da177e4SLinus Torvalds /* 30258f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 30268f4e2101SHugh Dickins * while we released the pte lock. 30271da177e4SLinus Torvalds */ 30288f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 30291da177e4SLinus Torvalds if (likely(pte_same(*page_table, orig_pte))) 30301da177e4SLinus Torvalds ret = VM_FAULT_OOM; 30310ff92245SShailabh Nagar delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 303265500d23SHugh Dickins goto unlock; 30331da177e4SLinus Torvalds } 30341da177e4SLinus Torvalds 30351da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 30361da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 3037f8891e5eSChristoph Lameter count_vm_event(PGMAJFAULT); 3038456f998eSYing Han mem_cgroup_count_vm_event(mm, PGMAJFAULT); 3039d1737fdbSAndi Kleen } else if (PageHWPoison(page)) { 304071f72525SWu Fengguang /* 304171f72525SWu Fengguang * hwpoisoned dirty swapcache pages are kept for killing 304271f72525SWu Fengguang * owner processes (which may be unknown at hwpoison time) 304371f72525SWu Fengguang */ 3044d1737fdbSAndi Kleen ret = VM_FAULT_HWPOISON; 3045d1737fdbSAndi Kleen delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 304656f31801SHugh Dickins swapcache = page; 30474779cb31SAndi Kleen goto out_release; 30481da177e4SLinus Torvalds } 30491da177e4SLinus Torvalds 305056f31801SHugh Dickins swapcache = page; 3051d065bd81SMichel Lespinasse locked = lock_page_or_retry(page, mm, flags); 3052e709ffd6SRik van Riel 305320a1022dSBalbir Singh delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 3054d065bd81SMichel Lespinasse if (!locked) { 3055d065bd81SMichel Lespinasse ret |= VM_FAULT_RETRY; 3056d065bd81SMichel Lespinasse goto out_release; 3057d065bd81SMichel Lespinasse } 30581da177e4SLinus Torvalds 30594969c119SAndrea Arcangeli /* 306031c4a3d3SHugh Dickins * Make sure try_to_free_swap or reuse_swap_page or swapoff did not 306131c4a3d3SHugh Dickins * release the swapcache from under us. The page pin, and pte_same 306231c4a3d3SHugh Dickins * test below, are not enough to exclude that. Even if it is still 306331c4a3d3SHugh Dickins * swapcache, we need to check that the page's swap has not changed. 30644969c119SAndrea Arcangeli */ 306531c4a3d3SHugh Dickins if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val)) 30664969c119SAndrea Arcangeli goto out_page; 30674969c119SAndrea Arcangeli 3068cbf86cfeSHugh Dickins page = ksm_might_need_to_copy(page, vma, address); 30694969c119SAndrea Arcangeli if (unlikely(!page)) { 30705ad64688SHugh Dickins ret = VM_FAULT_OOM; 30714969c119SAndrea Arcangeli page = swapcache; 30724969c119SAndrea Arcangeli goto out_page; 30734969c119SAndrea Arcangeli } 30745ad64688SHugh Dickins 30752c26fdd7SKAMEZAWA Hiroyuki if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) { 3076073e587eSKAMEZAWA Hiroyuki ret = VM_FAULT_OOM; 3077bc43f75cSJohannes Weiner goto out_page; 3078073e587eSKAMEZAWA Hiroyuki } 3079073e587eSKAMEZAWA Hiroyuki 30801da177e4SLinus Torvalds /* 30818f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 30821da177e4SLinus Torvalds */ 30838f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 30849e9bef07SHugh Dickins if (unlikely(!pte_same(*page_table, orig_pte))) 3085b8107480SKirill Korotaev goto out_nomap; 3086b8107480SKirill Korotaev 3087b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 3088b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 3089b8107480SKirill Korotaev goto out_nomap; 30901da177e4SLinus Torvalds } 30911da177e4SLinus Torvalds 30928c7c6e34SKAMEZAWA Hiroyuki /* 30938c7c6e34SKAMEZAWA Hiroyuki * The page isn't present yet, go ahead with the fault. 30948c7c6e34SKAMEZAWA Hiroyuki * 30958c7c6e34SKAMEZAWA Hiroyuki * Be careful about the sequence of operations here. 30968c7c6e34SKAMEZAWA Hiroyuki * To get its accounting right, reuse_swap_page() must be called 30978c7c6e34SKAMEZAWA Hiroyuki * while the page is counted on swap but not yet in mapcount i.e. 30988c7c6e34SKAMEZAWA Hiroyuki * before page_add_anon_rmap() and swap_free(); try_to_free_swap() 30998c7c6e34SKAMEZAWA Hiroyuki * must be called after the swap_free(), or it will never succeed. 310003f3c433SKAMEZAWA Hiroyuki * Because delete_from_swap_page() may be called by reuse_swap_page(), 310103f3c433SKAMEZAWA Hiroyuki * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry 310203f3c433SKAMEZAWA Hiroyuki * in page->private. In this case, a record in swap_cgroup is silently 310303f3c433SKAMEZAWA Hiroyuki * discarded at swap_free(). 31048c7c6e34SKAMEZAWA Hiroyuki */ 31051da177e4SLinus Torvalds 310634e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_ANONPAGES); 3107b084d435SKAMEZAWA Hiroyuki dec_mm_counter_fast(mm, MM_SWAPENTS); 31081da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 310930c9f3a9SLinus Torvalds if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) { 31101da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 311130c9f3a9SLinus Torvalds flags &= ~FAULT_FLAG_WRITE; 31129a5b489bSAndrea Arcangeli ret |= VM_FAULT_WRITE; 3113ad8c2ee8SRik van Riel exclusive = 1; 31141da177e4SLinus Torvalds } 31151da177e4SLinus Torvalds flush_icache_page(vma, page); 3116179ef71cSCyrill Gorcunov if (pte_swp_soft_dirty(orig_pte)) 3117179ef71cSCyrill Gorcunov pte = pte_mksoft_dirty(pte); 31181da177e4SLinus Torvalds set_pte_at(mm, address, page_table, pte); 311956f31801SHugh Dickins if (page == swapcache) 3120ad8c2ee8SRik van Riel do_page_add_anon_rmap(page, vma, address, exclusive); 312156f31801SHugh Dickins else /* ksm created a completely new copy */ 312256f31801SHugh Dickins page_add_new_anon_rmap(page, vma, address); 312303f3c433SKAMEZAWA Hiroyuki /* It's better to call commit-charge after rmap is established */ 312403f3c433SKAMEZAWA Hiroyuki mem_cgroup_commit_charge_swapin(page, ptr); 31251da177e4SLinus Torvalds 3126c475a8abSHugh Dickins swap_free(entry); 3127b291f000SNick Piggin if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) 3128a2c43eedSHugh Dickins try_to_free_swap(page); 3129c475a8abSHugh Dickins unlock_page(page); 313056f31801SHugh Dickins if (page != swapcache) { 31314969c119SAndrea Arcangeli /* 31324969c119SAndrea Arcangeli * Hold the lock to avoid the swap entry to be reused 31334969c119SAndrea Arcangeli * until we take the PT lock for the pte_same() check 31344969c119SAndrea Arcangeli * (to avoid false positives from pte_same). For 31354969c119SAndrea Arcangeli * further safety release the lock after the swap_free 31364969c119SAndrea Arcangeli * so that the swap count won't change under a 31374969c119SAndrea Arcangeli * parallel locked swapcache. 31384969c119SAndrea Arcangeli */ 31394969c119SAndrea Arcangeli unlock_page(swapcache); 31404969c119SAndrea Arcangeli page_cache_release(swapcache); 31414969c119SAndrea Arcangeli } 3142c475a8abSHugh Dickins 314330c9f3a9SLinus Torvalds if (flags & FAULT_FLAG_WRITE) { 314461469f1dSHugh Dickins ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); 314561469f1dSHugh Dickins if (ret & VM_FAULT_ERROR) 314661469f1dSHugh Dickins ret &= VM_FAULT_ERROR; 31471da177e4SLinus Torvalds goto out; 31481da177e4SLinus Torvalds } 31491da177e4SLinus Torvalds 31501da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 31514b3073e1SRussell King update_mmu_cache(vma, address, page_table); 315265500d23SHugh Dickins unlock: 31538f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 31541da177e4SLinus Torvalds out: 31551da177e4SLinus Torvalds return ret; 3156b8107480SKirill Korotaev out_nomap: 31577a81b88cSKAMEZAWA Hiroyuki mem_cgroup_cancel_charge_swapin(ptr); 31588f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 3159bc43f75cSJohannes Weiner out_page: 3160b8107480SKirill Korotaev unlock_page(page); 31614779cb31SAndi Kleen out_release: 3162b8107480SKirill Korotaev page_cache_release(page); 316356f31801SHugh Dickins if (page != swapcache) { 31644969c119SAndrea Arcangeli unlock_page(swapcache); 31654969c119SAndrea Arcangeli page_cache_release(swapcache); 31664969c119SAndrea Arcangeli } 316765500d23SHugh Dickins return ret; 31681da177e4SLinus Torvalds } 31691da177e4SLinus Torvalds 31701da177e4SLinus Torvalds /* 31718ca3eb08SLuck, Tony * This is like a special single-page "expand_{down|up}wards()", 31728ca3eb08SLuck, Tony * except we must first make sure that 'address{-|+}PAGE_SIZE' 3173320b2b8dSLinus Torvalds * doesn't hit another vma. 3174320b2b8dSLinus Torvalds */ 3175320b2b8dSLinus Torvalds static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) 3176320b2b8dSLinus Torvalds { 3177320b2b8dSLinus Torvalds address &= PAGE_MASK; 3178320b2b8dSLinus Torvalds if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) { 31790e8e50e2SLinus Torvalds struct vm_area_struct *prev = vma->vm_prev; 3180320b2b8dSLinus Torvalds 31810e8e50e2SLinus Torvalds /* 31820e8e50e2SLinus Torvalds * Is there a mapping abutting this one below? 31830e8e50e2SLinus Torvalds * 31840e8e50e2SLinus Torvalds * That's only ok if it's the same stack mapping 31850e8e50e2SLinus Torvalds * that has gotten split.. 31860e8e50e2SLinus Torvalds */ 31870e8e50e2SLinus Torvalds if (prev && prev->vm_end == address) 31880e8e50e2SLinus Torvalds return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; 31890e8e50e2SLinus Torvalds 3190d05f3169SMichal Hocko expand_downwards(vma, address - PAGE_SIZE); 3191320b2b8dSLinus Torvalds } 31928ca3eb08SLuck, Tony if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { 31938ca3eb08SLuck, Tony struct vm_area_struct *next = vma->vm_next; 31948ca3eb08SLuck, Tony 31958ca3eb08SLuck, Tony /* As VM_GROWSDOWN but s/below/above/ */ 31968ca3eb08SLuck, Tony if (next && next->vm_start == address + PAGE_SIZE) 31978ca3eb08SLuck, Tony return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; 31988ca3eb08SLuck, Tony 31998ca3eb08SLuck, Tony expand_upwards(vma, address + PAGE_SIZE); 32008ca3eb08SLuck, Tony } 3201320b2b8dSLinus Torvalds return 0; 3202320b2b8dSLinus Torvalds } 3203320b2b8dSLinus Torvalds 3204320b2b8dSLinus Torvalds /* 32058f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 32068f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 32078f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 32081da177e4SLinus Torvalds */ 320965500d23SHugh Dickins static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 321065500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 321130c9f3a9SLinus Torvalds unsigned int flags) 32121da177e4SLinus Torvalds { 32138f4e2101SHugh Dickins struct page *page; 32148f4e2101SHugh Dickins spinlock_t *ptl; 32151da177e4SLinus Torvalds pte_t entry; 32161da177e4SLinus Torvalds 32175528f913SLinus Torvalds pte_unmap(page_table); 3218320b2b8dSLinus Torvalds 321911ac5524SLinus Torvalds /* Check if we need to add a guard page to the stack */ 322011ac5524SLinus Torvalds if (check_stack_guard_page(vma, address) < 0) 322111ac5524SLinus Torvalds return VM_FAULT_SIGBUS; 322211ac5524SLinus Torvalds 322311ac5524SLinus Torvalds /* Use the zero-page for reads */ 322462eede62SHugh Dickins if (!(flags & FAULT_FLAG_WRITE)) { 322562eede62SHugh Dickins entry = pte_mkspecial(pfn_pte(my_zero_pfn(address), 322662eede62SHugh Dickins vma->vm_page_prot)); 322711ac5524SLinus Torvalds page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 3228a13ea5b7SHugh Dickins if (!pte_none(*page_table)) 3229a13ea5b7SHugh Dickins goto unlock; 3230a13ea5b7SHugh Dickins goto setpte; 3231a13ea5b7SHugh Dickins } 3232a13ea5b7SHugh Dickins 32331da177e4SLinus Torvalds /* Allocate our own private page. */ 32341da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 323565500d23SHugh Dickins goto oom; 3236769848c0SMel Gorman page = alloc_zeroed_user_highpage_movable(vma, address); 32371da177e4SLinus Torvalds if (!page) 323865500d23SHugh Dickins goto oom; 323952f37629SMinchan Kim /* 324052f37629SMinchan Kim * The memory barrier inside __SetPageUptodate makes sure that 324152f37629SMinchan Kim * preceeding stores to the page contents become visible before 324252f37629SMinchan Kim * the set_pte_at() write. 324352f37629SMinchan Kim */ 32440ed361deSNick Piggin __SetPageUptodate(page); 32451da177e4SLinus Torvalds 32462c26fdd7SKAMEZAWA Hiroyuki if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) 32478a9f3ccdSBalbir Singh goto oom_free_page; 32488a9f3ccdSBalbir Singh 324965500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 32501ac0cb5dSHugh Dickins if (vma->vm_flags & VM_WRITE) 32511ac0cb5dSHugh Dickins entry = pte_mkwrite(pte_mkdirty(entry)); 32528f4e2101SHugh Dickins 32538f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 32541c2fb7a4SAndrea Arcangeli if (!pte_none(*page_table)) 32558f4e2101SHugh Dickins goto release; 32569ba69294SHugh Dickins 325734e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_ANONPAGES); 32589617d95eSNick Piggin page_add_new_anon_rmap(page, vma, address); 3259a13ea5b7SHugh Dickins setpte: 326065500d23SHugh Dickins set_pte_at(mm, address, page_table, entry); 32611da177e4SLinus Torvalds 32621da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 32634b3073e1SRussell King update_mmu_cache(vma, address, page_table); 326465500d23SHugh Dickins unlock: 32658f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 326683c54070SNick Piggin return 0; 32678f4e2101SHugh Dickins release: 32688a9f3ccdSBalbir Singh mem_cgroup_uncharge_page(page); 32698f4e2101SHugh Dickins page_cache_release(page); 32708f4e2101SHugh Dickins goto unlock; 32718a9f3ccdSBalbir Singh oom_free_page: 32726dbf6d3bSHugh Dickins page_cache_release(page); 327365500d23SHugh Dickins oom: 32741da177e4SLinus Torvalds return VM_FAULT_OOM; 32751da177e4SLinus Torvalds } 32761da177e4SLinus Torvalds 32771da177e4SLinus Torvalds /* 327854cb8821SNick Piggin * __do_fault() tries to create a new page mapping. It aggressively 32791da177e4SLinus Torvalds * tries to share with existing pages, but makes a separate copy if 328054cb8821SNick Piggin * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid 328154cb8821SNick Piggin * the next page fault. 32821da177e4SLinus Torvalds * 32831da177e4SLinus Torvalds * As this is called only for pages that do not currently exist, we 32841da177e4SLinus Torvalds * do not need to flush old virtual caches or the TLB. 32851da177e4SLinus Torvalds * 32868f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 328716abfa08SHugh Dickins * but allow concurrent faults), and pte neither mapped nor locked. 32888f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 32891da177e4SLinus Torvalds */ 329054cb8821SNick Piggin static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, 329116abfa08SHugh Dickins unsigned long address, pmd_t *pmd, 329254cb8821SNick Piggin pgoff_t pgoff, unsigned int flags, pte_t orig_pte) 32931da177e4SLinus Torvalds { 329416abfa08SHugh Dickins pte_t *page_table; 32958f4e2101SHugh Dickins spinlock_t *ptl; 3296d0217ac0SNick Piggin struct page *page; 32971d65f86dSKAMEZAWA Hiroyuki struct page *cow_page; 32981da177e4SLinus Torvalds pte_t entry; 32991da177e4SLinus Torvalds int anon = 0; 3300d08b3851SPeter Zijlstra struct page *dirty_page = NULL; 3301d0217ac0SNick Piggin struct vm_fault vmf; 3302d0217ac0SNick Piggin int ret; 3303a200ee18SPeter Zijlstra int page_mkwrite = 0; 330454cb8821SNick Piggin 33051d65f86dSKAMEZAWA Hiroyuki /* 33061d65f86dSKAMEZAWA Hiroyuki * If we do COW later, allocate page befor taking lock_page() 33071d65f86dSKAMEZAWA Hiroyuki * on the file cache page. This will reduce lock holding time. 33081d65f86dSKAMEZAWA Hiroyuki */ 33091d65f86dSKAMEZAWA Hiroyuki if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 33101d65f86dSKAMEZAWA Hiroyuki 33111d65f86dSKAMEZAWA Hiroyuki if (unlikely(anon_vma_prepare(vma))) 33121d65f86dSKAMEZAWA Hiroyuki return VM_FAULT_OOM; 33131d65f86dSKAMEZAWA Hiroyuki 33141d65f86dSKAMEZAWA Hiroyuki cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); 33151d65f86dSKAMEZAWA Hiroyuki if (!cow_page) 33161d65f86dSKAMEZAWA Hiroyuki return VM_FAULT_OOM; 33171d65f86dSKAMEZAWA Hiroyuki 33181d65f86dSKAMEZAWA Hiroyuki if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) { 33191d65f86dSKAMEZAWA Hiroyuki page_cache_release(cow_page); 33201d65f86dSKAMEZAWA Hiroyuki return VM_FAULT_OOM; 33211d65f86dSKAMEZAWA Hiroyuki } 33221d65f86dSKAMEZAWA Hiroyuki } else 33231d65f86dSKAMEZAWA Hiroyuki cow_page = NULL; 33241d65f86dSKAMEZAWA Hiroyuki 3325d0217ac0SNick Piggin vmf.virtual_address = (void __user *)(address & PAGE_MASK); 3326d0217ac0SNick Piggin vmf.pgoff = pgoff; 3327d0217ac0SNick Piggin vmf.flags = flags; 3328d0217ac0SNick Piggin vmf.page = NULL; 33291da177e4SLinus Torvalds 3330d0217ac0SNick Piggin ret = vma->vm_ops->fault(vma, &vmf); 3331d065bd81SMichel Lespinasse if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 3332d065bd81SMichel Lespinasse VM_FAULT_RETRY))) 33331d65f86dSKAMEZAWA Hiroyuki goto uncharge_out; 33341da177e4SLinus Torvalds 3335a3b947eaSAndi Kleen if (unlikely(PageHWPoison(vmf.page))) { 3336a3b947eaSAndi Kleen if (ret & VM_FAULT_LOCKED) 3337a3b947eaSAndi Kleen unlock_page(vmf.page); 33381d65f86dSKAMEZAWA Hiroyuki ret = VM_FAULT_HWPOISON; 33391d65f86dSKAMEZAWA Hiroyuki goto uncharge_out; 3340a3b947eaSAndi Kleen } 3341a3b947eaSAndi Kleen 3342d00806b1SNick Piggin /* 3343d0217ac0SNick Piggin * For consistency in subsequent calls, make the faulted page always 3344d00806b1SNick Piggin * locked. 3345d00806b1SNick Piggin */ 334683c54070SNick Piggin if (unlikely(!(ret & VM_FAULT_LOCKED))) 3347d0217ac0SNick Piggin lock_page(vmf.page); 334854cb8821SNick Piggin else 3349d0217ac0SNick Piggin VM_BUG_ON(!PageLocked(vmf.page)); 3350d00806b1SNick Piggin 33511da177e4SLinus Torvalds /* 33521da177e4SLinus Torvalds * Should we do an early C-O-W break? 33531da177e4SLinus Torvalds */ 3354d0217ac0SNick Piggin page = vmf.page; 335554cb8821SNick Piggin if (flags & FAULT_FLAG_WRITE) { 33569637a5efSDavid Howells if (!(vma->vm_flags & VM_SHARED)) { 33571d65f86dSKAMEZAWA Hiroyuki page = cow_page; 335854cb8821SNick Piggin anon = 1; 3359d0217ac0SNick Piggin copy_user_highpage(page, vmf.page, address, vma); 33600ed361deSNick Piggin __SetPageUptodate(page); 33619637a5efSDavid Howells } else { 336254cb8821SNick Piggin /* 336354cb8821SNick Piggin * If the page will be shareable, see if the backing 33649637a5efSDavid Howells * address space wants to know that the page is about 336554cb8821SNick Piggin * to become writable 336654cb8821SNick Piggin */ 336769676147SMark Fasheh if (vma->vm_ops->page_mkwrite) { 3368c2ec175cSNick Piggin int tmp; 3369c2ec175cSNick Piggin 337069676147SMark Fasheh unlock_page(page); 3371b827e496SNick Piggin vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; 3372c2ec175cSNick Piggin tmp = vma->vm_ops->page_mkwrite(vma, &vmf); 3373c2ec175cSNick Piggin if (unlikely(tmp & 3374c2ec175cSNick Piggin (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { 3375c2ec175cSNick Piggin ret = tmp; 3376b827e496SNick Piggin goto unwritable_page; 337769676147SMark Fasheh } 3378b827e496SNick Piggin if (unlikely(!(tmp & VM_FAULT_LOCKED))) { 337969676147SMark Fasheh lock_page(page); 3380d0217ac0SNick Piggin if (!page->mapping) { 3381b827e496SNick Piggin ret = 0; /* retry the fault */ 3382b827e496SNick Piggin unlock_page(page); 3383b827e496SNick Piggin goto unwritable_page; 3384d0217ac0SNick Piggin } 3385b827e496SNick Piggin } else 3386b827e496SNick Piggin VM_BUG_ON(!PageLocked(page)); 3387a200ee18SPeter Zijlstra page_mkwrite = 1; 33889637a5efSDavid Howells } 33899637a5efSDavid Howells } 339054cb8821SNick Piggin 33911da177e4SLinus Torvalds } 33921da177e4SLinus Torvalds 33938f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 33941da177e4SLinus Torvalds 33951da177e4SLinus Torvalds /* 33961da177e4SLinus Torvalds * This silly early PAGE_DIRTY setting removes a race 33971da177e4SLinus Torvalds * due to the bad i386 page protection. But it's valid 33981da177e4SLinus Torvalds * for other architectures too. 33991da177e4SLinus Torvalds * 340030c9f3a9SLinus Torvalds * Note that if FAULT_FLAG_WRITE is set, we either now have 34011da177e4SLinus Torvalds * an exclusive copy of the page, or this is a shared mapping, 34021da177e4SLinus Torvalds * so we can make it writable and dirty to avoid having to 34031da177e4SLinus Torvalds * handle that later. 34041da177e4SLinus Torvalds */ 34051da177e4SLinus Torvalds /* Only go through if we didn't race with anybody else... */ 34061c2fb7a4SAndrea Arcangeli if (likely(pte_same(*page_table, orig_pte))) { 3407d00806b1SNick Piggin flush_icache_page(vma, page); 3408d00806b1SNick Piggin entry = mk_pte(page, vma->vm_page_prot); 340954cb8821SNick Piggin if (flags & FAULT_FLAG_WRITE) 34101da177e4SLinus Torvalds entry = maybe_mkwrite(pte_mkdirty(entry), vma); 341141bb3476SCyrill Gorcunov else if (pte_file(orig_pte) && pte_file_soft_dirty(orig_pte)) 341241bb3476SCyrill Gorcunov pte_mksoft_dirty(entry); 34131da177e4SLinus Torvalds if (anon) { 341434e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_ANONPAGES); 3415d00806b1SNick Piggin page_add_new_anon_rmap(page, vma, address); 3416f57e88a8SHugh Dickins } else { 341734e55232SKAMEZAWA Hiroyuki inc_mm_counter_fast(mm, MM_FILEPAGES); 3418d00806b1SNick Piggin page_add_file_rmap(page); 341954cb8821SNick Piggin if (flags & FAULT_FLAG_WRITE) { 3420d00806b1SNick Piggin dirty_page = page; 3421d08b3851SPeter Zijlstra get_page(dirty_page); 3422d08b3851SPeter Zijlstra } 34234294621fSHugh Dickins } 342464d6519dSLee Schermerhorn set_pte_at(mm, address, page_table, entry); 34251da177e4SLinus Torvalds 3426d00806b1SNick Piggin /* no need to invalidate: a not-present page won't be cached */ 34274b3073e1SRussell King update_mmu_cache(vma, address, page_table); 3428d00806b1SNick Piggin } else { 34291d65f86dSKAMEZAWA Hiroyuki if (cow_page) 34301d65f86dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(cow_page); 3431d00806b1SNick Piggin if (anon) 3432d00806b1SNick Piggin page_cache_release(page); 3433d00806b1SNick Piggin else 343454cb8821SNick Piggin anon = 1; /* no anon but release faulted_page */ 3435d00806b1SNick Piggin } 3436d00806b1SNick Piggin 34378f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 3438d00806b1SNick Piggin 3439b827e496SNick Piggin if (dirty_page) { 3440b827e496SNick Piggin struct address_space *mapping = page->mapping; 344141c4d25fSJan Kara int dirtied = 0; 34428f7b3d15SAnton Salikhmetov 3443b827e496SNick Piggin if (set_page_dirty(dirty_page)) 344441c4d25fSJan Kara dirtied = 1; 3445b827e496SNick Piggin unlock_page(dirty_page); 3446d08b3851SPeter Zijlstra put_page(dirty_page); 344741c4d25fSJan Kara if ((dirtied || page_mkwrite) && mapping) { 3448b827e496SNick Piggin /* 3449b827e496SNick Piggin * Some device drivers do not set page.mapping but still 3450b827e496SNick Piggin * dirty their pages 3451b827e496SNick Piggin */ 3452b827e496SNick Piggin balance_dirty_pages_ratelimited(mapping); 3453d08b3851SPeter Zijlstra } 3454d00806b1SNick Piggin 3455b827e496SNick Piggin /* file_update_time outside page_lock */ 345641c4d25fSJan Kara if (vma->vm_file && !page_mkwrite) 3457b827e496SNick Piggin file_update_time(vma->vm_file); 3458b827e496SNick Piggin } else { 3459b827e496SNick Piggin unlock_page(vmf.page); 3460b827e496SNick Piggin if (anon) 3461b827e496SNick Piggin page_cache_release(vmf.page); 3462b827e496SNick Piggin } 3463b827e496SNick Piggin 3464b827e496SNick Piggin return ret; 3465b827e496SNick Piggin 3466b827e496SNick Piggin unwritable_page: 3467b827e496SNick Piggin page_cache_release(page); 346883c54070SNick Piggin return ret; 34691d65f86dSKAMEZAWA Hiroyuki uncharge_out: 34701d65f86dSKAMEZAWA Hiroyuki /* fs's fault handler get error */ 34711d65f86dSKAMEZAWA Hiroyuki if (cow_page) { 34721d65f86dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_page(cow_page); 34731d65f86dSKAMEZAWA Hiroyuki page_cache_release(cow_page); 34741d65f86dSKAMEZAWA Hiroyuki } 34751d65f86dSKAMEZAWA Hiroyuki return ret; 347654cb8821SNick Piggin } 3477d00806b1SNick Piggin 347854cb8821SNick Piggin static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, 347954cb8821SNick Piggin unsigned long address, pte_t *page_table, pmd_t *pmd, 348030c9f3a9SLinus Torvalds unsigned int flags, pte_t orig_pte) 348154cb8821SNick Piggin { 348254cb8821SNick Piggin pgoff_t pgoff = (((address & PAGE_MASK) 34830da7e01fSDean Nelson - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; 348454cb8821SNick Piggin 348516abfa08SHugh Dickins pte_unmap(page_table); 348616abfa08SHugh Dickins return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); 348754cb8821SNick Piggin } 348854cb8821SNick Piggin 3489f4b81804SJes Sorensen /* 34901da177e4SLinus Torvalds * Fault of a previously existing named mapping. Repopulate the pte 34911da177e4SLinus Torvalds * from the encoded file_pte if possible. This enables swappable 34921da177e4SLinus Torvalds * nonlinear vmas. 34938f4e2101SHugh Dickins * 34948f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 34958f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 34968f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 34971da177e4SLinus Torvalds */ 3498d0217ac0SNick Piggin static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, 349965500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 350030c9f3a9SLinus Torvalds unsigned int flags, pte_t orig_pte) 35011da177e4SLinus Torvalds { 350265500d23SHugh Dickins pgoff_t pgoff; 35031da177e4SLinus Torvalds 350430c9f3a9SLinus Torvalds flags |= FAULT_FLAG_NONLINEAR; 350530c9f3a9SLinus Torvalds 35064c21e2f2SHugh Dickins if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 350783c54070SNick Piggin return 0; 35081da177e4SLinus Torvalds 35092509ef26SHugh Dickins if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { 351065500d23SHugh Dickins /* 351165500d23SHugh Dickins * Page table corrupted: show pte and kill process. 351265500d23SHugh Dickins */ 35133dc14741SHugh Dickins print_bad_pte(vma, address, orig_pte, NULL); 3514d99be1a8SHugh Dickins return VM_FAULT_SIGBUS; 351565500d23SHugh Dickins } 351665500d23SHugh Dickins 351765500d23SHugh Dickins pgoff = pte_to_pgoff(orig_pte); 351816abfa08SHugh Dickins return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); 35191da177e4SLinus Torvalds } 35201da177e4SLinus Torvalds 35219532fec1SMel Gorman int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, 35229532fec1SMel Gorman unsigned long addr, int current_nid) 35239532fec1SMel Gorman { 35249532fec1SMel Gorman get_page(page); 35259532fec1SMel Gorman 35269532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS); 35279532fec1SMel Gorman if (current_nid == numa_node_id()) 35289532fec1SMel Gorman count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); 35299532fec1SMel Gorman 35309532fec1SMel Gorman return mpol_misplaced(page, vma, addr); 35319532fec1SMel Gorman } 35329532fec1SMel Gorman 3533d10e63f2SMel Gorman int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 3534d10e63f2SMel Gorman unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd) 3535d10e63f2SMel Gorman { 35364daae3b4SMel Gorman struct page *page = NULL; 3537d10e63f2SMel Gorman spinlock_t *ptl; 3538cbee9f88SPeter Zijlstra int current_nid = -1; 3539cbee9f88SPeter Zijlstra int target_nid; 3540b8593bfdSMel Gorman bool migrated = false; 3541d10e63f2SMel Gorman 3542d10e63f2SMel Gorman /* 3543d10e63f2SMel Gorman * The "pte" at this point cannot be used safely without 3544d10e63f2SMel Gorman * validation through pte_unmap_same(). It's of NUMA type but 3545d10e63f2SMel Gorman * the pfn may be screwed if the read is non atomic. 3546d10e63f2SMel Gorman * 3547d10e63f2SMel Gorman * ptep_modify_prot_start is not called as this is clearing 3548d10e63f2SMel Gorman * the _PAGE_NUMA bit and it is not really expected that there 3549d10e63f2SMel Gorman * would be concurrent hardware modifications to the PTE. 3550d10e63f2SMel Gorman */ 3551d10e63f2SMel Gorman ptl = pte_lockptr(mm, pmd); 3552d10e63f2SMel Gorman spin_lock(ptl); 35534daae3b4SMel Gorman if (unlikely(!pte_same(*ptep, pte))) { 35544daae3b4SMel Gorman pte_unmap_unlock(ptep, ptl); 35554daae3b4SMel Gorman goto out; 35564daae3b4SMel Gorman } 35574daae3b4SMel Gorman 3558d10e63f2SMel Gorman pte = pte_mknonnuma(pte); 3559d10e63f2SMel Gorman set_pte_at(mm, addr, ptep, pte); 3560d10e63f2SMel Gorman update_mmu_cache(vma, addr, ptep); 3561d10e63f2SMel Gorman 3562d10e63f2SMel Gorman page = vm_normal_page(vma, addr, pte); 3563d10e63f2SMel Gorman if (!page) { 3564d10e63f2SMel Gorman pte_unmap_unlock(ptep, ptl); 3565d10e63f2SMel Gorman return 0; 3566d10e63f2SMel Gorman } 3567d10e63f2SMel Gorman 35684daae3b4SMel Gorman current_nid = page_to_nid(page); 35699532fec1SMel Gorman target_nid = numa_migrate_prep(page, vma, addr, current_nid); 3570d10e63f2SMel Gorman pte_unmap_unlock(ptep, ptl); 35714daae3b4SMel Gorman if (target_nid == -1) { 35724daae3b4SMel Gorman /* 35734daae3b4SMel Gorman * Account for the fault against the current node if it not 35744daae3b4SMel Gorman * being replaced regardless of where the page is located. 35754daae3b4SMel Gorman */ 35764daae3b4SMel Gorman current_nid = numa_node_id(); 35774daae3b4SMel Gorman put_page(page); 35784daae3b4SMel Gorman goto out; 35794daae3b4SMel Gorman } 35804daae3b4SMel Gorman 35814daae3b4SMel Gorman /* Migrate to the requested node */ 3582b8593bfdSMel Gorman migrated = migrate_misplaced_page(page, target_nid); 3583b8593bfdSMel Gorman if (migrated) 35844daae3b4SMel Gorman current_nid = target_nid; 35854daae3b4SMel Gorman 35864daae3b4SMel Gorman out: 35879532fec1SMel Gorman if (current_nid != -1) 3588b8593bfdSMel Gorman task_numa_fault(current_nid, 1, migrated); 3589d10e63f2SMel Gorman return 0; 3590d10e63f2SMel Gorman } 3591d10e63f2SMel Gorman 3592d10e63f2SMel Gorman /* NUMA hinting page fault entry point for regular pmds */ 3593d10e63f2SMel Gorman #ifdef CONFIG_NUMA_BALANCING 3594d10e63f2SMel Gorman static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 3595d10e63f2SMel Gorman unsigned long addr, pmd_t *pmdp) 3596d10e63f2SMel Gorman { 3597d10e63f2SMel Gorman pmd_t pmd; 3598d10e63f2SMel Gorman pte_t *pte, *orig_pte; 3599d10e63f2SMel Gorman unsigned long _addr = addr & PMD_MASK; 3600d10e63f2SMel Gorman unsigned long offset; 3601d10e63f2SMel Gorman spinlock_t *ptl; 3602d10e63f2SMel Gorman bool numa = false; 360303c5a6e1SMel Gorman int local_nid = numa_node_id(); 3604d10e63f2SMel Gorman 3605d10e63f2SMel Gorman spin_lock(&mm->page_table_lock); 3606d10e63f2SMel Gorman pmd = *pmdp; 3607d10e63f2SMel Gorman if (pmd_numa(pmd)) { 3608d10e63f2SMel Gorman set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd)); 3609d10e63f2SMel Gorman numa = true; 3610d10e63f2SMel Gorman } 3611d10e63f2SMel Gorman spin_unlock(&mm->page_table_lock); 3612d10e63f2SMel Gorman 3613d10e63f2SMel Gorman if (!numa) 3614d10e63f2SMel Gorman return 0; 3615d10e63f2SMel Gorman 3616d10e63f2SMel Gorman /* we're in a page fault so some vma must be in the range */ 3617d10e63f2SMel Gorman BUG_ON(!vma); 3618d10e63f2SMel Gorman BUG_ON(vma->vm_start >= _addr + PMD_SIZE); 3619d10e63f2SMel Gorman offset = max(_addr, vma->vm_start) & ~PMD_MASK; 3620d10e63f2SMel Gorman VM_BUG_ON(offset >= PMD_SIZE); 3621d10e63f2SMel Gorman orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl); 3622d10e63f2SMel Gorman pte += offset >> PAGE_SHIFT; 3623d10e63f2SMel Gorman for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) { 3624d10e63f2SMel Gorman pte_t pteval = *pte; 3625d10e63f2SMel Gorman struct page *page; 36269532fec1SMel Gorman int curr_nid = local_nid; 36279532fec1SMel Gorman int target_nid; 3628b8593bfdSMel Gorman bool migrated; 3629d10e63f2SMel Gorman if (!pte_present(pteval)) 3630d10e63f2SMel Gorman continue; 3631d10e63f2SMel Gorman if (!pte_numa(pteval)) 3632d10e63f2SMel Gorman continue; 3633d10e63f2SMel Gorman if (addr >= vma->vm_end) { 3634d10e63f2SMel Gorman vma = find_vma(mm, addr); 3635d10e63f2SMel Gorman /* there's a pte present so there must be a vma */ 3636d10e63f2SMel Gorman BUG_ON(!vma); 3637d10e63f2SMel Gorman BUG_ON(addr < vma->vm_start); 3638d10e63f2SMel Gorman } 3639d10e63f2SMel Gorman if (pte_numa(pteval)) { 3640d10e63f2SMel Gorman pteval = pte_mknonnuma(pteval); 3641d10e63f2SMel Gorman set_pte_at(mm, addr, pte, pteval); 3642d10e63f2SMel Gorman } 3643d10e63f2SMel Gorman page = vm_normal_page(vma, addr, pteval); 3644d10e63f2SMel Gorman if (unlikely(!page)) 3645d10e63f2SMel Gorman continue; 3646cbee9f88SPeter Zijlstra /* only check non-shared pages */ 3647cbee9f88SPeter Zijlstra if (unlikely(page_mapcount(page) != 1)) 3648cbee9f88SPeter Zijlstra continue; 36499532fec1SMel Gorman 36509532fec1SMel Gorman /* 36519532fec1SMel Gorman * Note that the NUMA fault is later accounted to either 36529532fec1SMel Gorman * the node that is currently running or where the page is 36539532fec1SMel Gorman * migrated to. 36549532fec1SMel Gorman */ 36559532fec1SMel Gorman curr_nid = local_nid; 36569532fec1SMel Gorman target_nid = numa_migrate_prep(page, vma, addr, 36579532fec1SMel Gorman page_to_nid(page)); 36589532fec1SMel Gorman if (target_nid == -1) { 36599532fec1SMel Gorman put_page(page); 36609532fec1SMel Gorman continue; 36619532fec1SMel Gorman } 36629532fec1SMel Gorman 36639532fec1SMel Gorman /* Migrate to the requested node */ 3664cbee9f88SPeter Zijlstra pte_unmap_unlock(pte, ptl); 3665b8593bfdSMel Gorman migrated = migrate_misplaced_page(page, target_nid); 3666b8593bfdSMel Gorman if (migrated) 36679532fec1SMel Gorman curr_nid = target_nid; 3668b8593bfdSMel Gorman task_numa_fault(curr_nid, 1, migrated); 3669cbee9f88SPeter Zijlstra 3670cbee9f88SPeter Zijlstra pte = pte_offset_map_lock(mm, pmdp, addr, &ptl); 3671d10e63f2SMel Gorman } 3672d10e63f2SMel Gorman pte_unmap_unlock(orig_pte, ptl); 3673d10e63f2SMel Gorman 3674d10e63f2SMel Gorman return 0; 3675d10e63f2SMel Gorman } 3676d10e63f2SMel Gorman #else 3677d10e63f2SMel Gorman static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 3678d10e63f2SMel Gorman unsigned long addr, pmd_t *pmdp) 3679d10e63f2SMel Gorman { 3680d10e63f2SMel Gorman BUG(); 3681b3dd2070SAndrew Morton return 0; 3682d10e63f2SMel Gorman } 3683d10e63f2SMel Gorman #endif /* CONFIG_NUMA_BALANCING */ 3684d10e63f2SMel Gorman 36851da177e4SLinus Torvalds /* 36861da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 36871da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 36881da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 36891da177e4SLinus Torvalds * 36901da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 36911da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 36921da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 36931da177e4SLinus Torvalds * 3694c74df32cSHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 3695c74df32cSHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 3696c74df32cSHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 36971da177e4SLinus Torvalds */ 369871e3aac0SAndrea Arcangeli int handle_pte_fault(struct mm_struct *mm, 36991da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long address, 370030c9f3a9SLinus Torvalds pte_t *pte, pmd_t *pmd, unsigned int flags) 37011da177e4SLinus Torvalds { 37021da177e4SLinus Torvalds pte_t entry; 37038f4e2101SHugh Dickins spinlock_t *ptl; 37041da177e4SLinus Torvalds 37058dab5241SBenjamin Herrenschmidt entry = *pte; 37061da177e4SLinus Torvalds if (!pte_present(entry)) { 370765500d23SHugh Dickins if (pte_none(entry)) { 3708f4b81804SJes Sorensen if (vma->vm_ops) { 37093c18ddd1SNick Piggin if (likely(vma->vm_ops->fault)) 371054cb8821SNick Piggin return do_linear_fault(mm, vma, address, 371130c9f3a9SLinus Torvalds pte, pmd, flags, entry); 3712f4b81804SJes Sorensen } 3713f4b81804SJes Sorensen return do_anonymous_page(mm, vma, address, 371430c9f3a9SLinus Torvalds pte, pmd, flags); 371565500d23SHugh Dickins } 37161da177e4SLinus Torvalds if (pte_file(entry)) 3717d0217ac0SNick Piggin return do_nonlinear_fault(mm, vma, address, 371830c9f3a9SLinus Torvalds pte, pmd, flags, entry); 371965500d23SHugh Dickins return do_swap_page(mm, vma, address, 372030c9f3a9SLinus Torvalds pte, pmd, flags, entry); 37211da177e4SLinus Torvalds } 37221da177e4SLinus Torvalds 3723d10e63f2SMel Gorman if (pte_numa(entry)) 3724d10e63f2SMel Gorman return do_numa_page(mm, vma, address, entry, pte, pmd); 3725d10e63f2SMel Gorman 37264c21e2f2SHugh Dickins ptl = pte_lockptr(mm, pmd); 37278f4e2101SHugh Dickins spin_lock(ptl); 37288f4e2101SHugh Dickins if (unlikely(!pte_same(*pte, entry))) 37298f4e2101SHugh Dickins goto unlock; 373030c9f3a9SLinus Torvalds if (flags & FAULT_FLAG_WRITE) { 37311da177e4SLinus Torvalds if (!pte_write(entry)) 37328f4e2101SHugh Dickins return do_wp_page(mm, vma, address, 37338f4e2101SHugh Dickins pte, pmd, ptl, entry); 37341da177e4SLinus Torvalds entry = pte_mkdirty(entry); 37351da177e4SLinus Torvalds } 37361da177e4SLinus Torvalds entry = pte_mkyoung(entry); 373730c9f3a9SLinus Torvalds if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) { 37384b3073e1SRussell King update_mmu_cache(vma, address, pte); 37391a44e149SAndrea Arcangeli } else { 37401a44e149SAndrea Arcangeli /* 37411a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 37421a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 37431a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 37441a44e149SAndrea Arcangeli * with threads. 37451a44e149SAndrea Arcangeli */ 374630c9f3a9SLinus Torvalds if (flags & FAULT_FLAG_WRITE) 374761c77326SShaohua Li flush_tlb_fix_spurious_fault(vma, address); 37481a44e149SAndrea Arcangeli } 37498f4e2101SHugh Dickins unlock: 37508f4e2101SHugh Dickins pte_unmap_unlock(pte, ptl); 375183c54070SNick Piggin return 0; 37521da177e4SLinus Torvalds } 37531da177e4SLinus Torvalds 37541da177e4SLinus Torvalds /* 37551da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 37561da177e4SLinus Torvalds */ 3757*519e5247SJohannes Weiner static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 3758d06063ccSLinus Torvalds unsigned long address, unsigned int flags) 37591da177e4SLinus Torvalds { 37601da177e4SLinus Torvalds pgd_t *pgd; 37611da177e4SLinus Torvalds pud_t *pud; 37621da177e4SLinus Torvalds pmd_t *pmd; 37631da177e4SLinus Torvalds pte_t *pte; 37641da177e4SLinus Torvalds 3765ac9b9c66SHugh Dickins if (unlikely(is_vm_hugetlb_page(vma))) 376630c9f3a9SLinus Torvalds return hugetlb_fault(mm, vma, address, flags); 37671da177e4SLinus Torvalds 37681f1d06c3SDavid Rientjes retry: 37691da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 37701da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, address); 37711da177e4SLinus Torvalds if (!pud) 3772c74df32cSHugh Dickins return VM_FAULT_OOM; 37731da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, address); 37741da177e4SLinus Torvalds if (!pmd) 3775c74df32cSHugh Dickins return VM_FAULT_OOM; 377671e3aac0SAndrea Arcangeli if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) { 377771e3aac0SAndrea Arcangeli if (!vma->vm_ops) 377871e3aac0SAndrea Arcangeli return do_huge_pmd_anonymous_page(mm, vma, address, 377971e3aac0SAndrea Arcangeli pmd, flags); 378071e3aac0SAndrea Arcangeli } else { 378171e3aac0SAndrea Arcangeli pmd_t orig_pmd = *pmd; 37821f1d06c3SDavid Rientjes int ret; 37831f1d06c3SDavid Rientjes 378471e3aac0SAndrea Arcangeli barrier(); 378571e3aac0SAndrea Arcangeli if (pmd_trans_huge(orig_pmd)) { 3786a1dd450bSWill Deacon unsigned int dirty = flags & FAULT_FLAG_WRITE; 3787a1dd450bSWill Deacon 3788e53289c0SLinus Torvalds /* 3789e53289c0SLinus Torvalds * If the pmd is splitting, return and retry the 3790e53289c0SLinus Torvalds * the fault. Alternative: wait until the split 3791e53289c0SLinus Torvalds * is done, and goto retry. 3792e53289c0SLinus Torvalds */ 3793e53289c0SLinus Torvalds if (pmd_trans_splitting(orig_pmd)) 3794e53289c0SLinus Torvalds return 0; 3795e53289c0SLinus Torvalds 37963d59eebcSLinus Torvalds if (pmd_numa(orig_pmd)) 37974daae3b4SMel Gorman return do_huge_pmd_numa_page(mm, vma, address, 3798d10e63f2SMel Gorman orig_pmd, pmd); 3799d10e63f2SMel Gorman 38003d59eebcSLinus Torvalds if (dirty && !pmd_write(orig_pmd)) { 38011f1d06c3SDavid Rientjes ret = do_huge_pmd_wp_page(mm, vma, address, pmd, 38021f1d06c3SDavid Rientjes orig_pmd); 38031f1d06c3SDavid Rientjes /* 38041f1d06c3SDavid Rientjes * If COW results in an oom, the huge pmd will 38051f1d06c3SDavid Rientjes * have been split, so retry the fault on the 38061f1d06c3SDavid Rientjes * pte for a smaller charge. 38071f1d06c3SDavid Rientjes */ 38081f1d06c3SDavid Rientjes if (unlikely(ret & VM_FAULT_OOM)) 38091f1d06c3SDavid Rientjes goto retry; 38101f1d06c3SDavid Rientjes return ret; 3811a1dd450bSWill Deacon } else { 3812a1dd450bSWill Deacon huge_pmd_set_accessed(mm, vma, address, pmd, 3813a1dd450bSWill Deacon orig_pmd, dirty); 38141f1d06c3SDavid Rientjes } 3815d10e63f2SMel Gorman 381671e3aac0SAndrea Arcangeli return 0; 381771e3aac0SAndrea Arcangeli } 381871e3aac0SAndrea Arcangeli } 381971e3aac0SAndrea Arcangeli 3820d10e63f2SMel Gorman if (pmd_numa(*pmd)) 3821d10e63f2SMel Gorman return do_pmd_numa_page(mm, vma, address, pmd); 3822d10e63f2SMel Gorman 382371e3aac0SAndrea Arcangeli /* 382471e3aac0SAndrea Arcangeli * Use __pte_alloc instead of pte_alloc_map, because we can't 382571e3aac0SAndrea Arcangeli * run pte_offset_map on the pmd, if an huge pmd could 382671e3aac0SAndrea Arcangeli * materialize from under us from a different thread. 382771e3aac0SAndrea Arcangeli */ 38284fd01770SMel Gorman if (unlikely(pmd_none(*pmd)) && 38294fd01770SMel Gorman unlikely(__pte_alloc(mm, vma, pmd, address))) 3830c74df32cSHugh Dickins return VM_FAULT_OOM; 383171e3aac0SAndrea Arcangeli /* if an huge pmd materialized from under us just retry later */ 383271e3aac0SAndrea Arcangeli if (unlikely(pmd_trans_huge(*pmd))) 383371e3aac0SAndrea Arcangeli return 0; 383471e3aac0SAndrea Arcangeli /* 383571e3aac0SAndrea Arcangeli * A regular pmd is established and it can't morph into a huge pmd 383671e3aac0SAndrea Arcangeli * from under us anymore at this point because we hold the mmap_sem 383771e3aac0SAndrea Arcangeli * read mode and khugepaged takes it in write mode. So now it's 383871e3aac0SAndrea Arcangeli * safe to run pte_offset_map(). 383971e3aac0SAndrea Arcangeli */ 384071e3aac0SAndrea Arcangeli pte = pte_offset_map(pmd, address); 38411da177e4SLinus Torvalds 384230c9f3a9SLinus Torvalds return handle_pte_fault(mm, vma, address, pte, pmd, flags); 38431da177e4SLinus Torvalds } 38441da177e4SLinus Torvalds 3845*519e5247SJohannes Weiner int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 3846*519e5247SJohannes Weiner unsigned long address, unsigned int flags) 3847*519e5247SJohannes Weiner { 3848*519e5247SJohannes Weiner int ret; 3849*519e5247SJohannes Weiner 3850*519e5247SJohannes Weiner __set_current_state(TASK_RUNNING); 3851*519e5247SJohannes Weiner 3852*519e5247SJohannes Weiner count_vm_event(PGFAULT); 3853*519e5247SJohannes Weiner mem_cgroup_count_vm_event(mm, PGFAULT); 3854*519e5247SJohannes Weiner 3855*519e5247SJohannes Weiner /* do counter updates before entering really critical section. */ 3856*519e5247SJohannes Weiner check_sync_rss_stat(current); 3857*519e5247SJohannes Weiner 3858*519e5247SJohannes Weiner /* 3859*519e5247SJohannes Weiner * Enable the memcg OOM handling for faults triggered in user 3860*519e5247SJohannes Weiner * space. Kernel faults are handled more gracefully. 3861*519e5247SJohannes Weiner */ 3862*519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 3863*519e5247SJohannes Weiner mem_cgroup_enable_oom(); 3864*519e5247SJohannes Weiner 3865*519e5247SJohannes Weiner ret = __handle_mm_fault(mm, vma, address, flags); 3866*519e5247SJohannes Weiner 3867*519e5247SJohannes Weiner if (flags & FAULT_FLAG_USER) 3868*519e5247SJohannes Weiner mem_cgroup_disable_oom(); 3869*519e5247SJohannes Weiner 3870*519e5247SJohannes Weiner return ret; 3871*519e5247SJohannes Weiner } 3872*519e5247SJohannes Weiner 38731da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 38741da177e4SLinus Torvalds /* 38751da177e4SLinus Torvalds * Allocate page upper directory. 3876872fec16SHugh Dickins * We've already handled the fast-path in-line. 38771da177e4SLinus Torvalds */ 38781bb3630eSHugh Dickins int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 38791da177e4SLinus Torvalds { 3880c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 3881c74df32cSHugh Dickins if (!new) 38821bb3630eSHugh Dickins return -ENOMEM; 38831da177e4SLinus Torvalds 3884362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 3885362a61adSNick Piggin 3886872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 38871bb3630eSHugh Dickins if (pgd_present(*pgd)) /* Another has populated it */ 38885e541973SBenjamin Herrenschmidt pud_free(mm, new); 38891bb3630eSHugh Dickins else 38901da177e4SLinus Torvalds pgd_populate(mm, pgd, new); 3891872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 38921bb3630eSHugh Dickins return 0; 38931da177e4SLinus Torvalds } 38941da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 38951da177e4SLinus Torvalds 38961da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 38971da177e4SLinus Torvalds /* 38981da177e4SLinus Torvalds * Allocate page middle directory. 3899872fec16SHugh Dickins * We've already handled the fast-path in-line. 39001da177e4SLinus Torvalds */ 39011bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 39021da177e4SLinus Torvalds { 3903c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 3904c74df32cSHugh Dickins if (!new) 39051bb3630eSHugh Dickins return -ENOMEM; 39061da177e4SLinus Torvalds 3907362a61adSNick Piggin smp_wmb(); /* See comment in __pte_alloc */ 3908362a61adSNick Piggin 3909872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 39101da177e4SLinus Torvalds #ifndef __ARCH_HAS_4LEVEL_HACK 39111bb3630eSHugh Dickins if (pud_present(*pud)) /* Another has populated it */ 39125e541973SBenjamin Herrenschmidt pmd_free(mm, new); 39131bb3630eSHugh Dickins else 39141da177e4SLinus Torvalds pud_populate(mm, pud, new); 39151da177e4SLinus Torvalds #else 39161bb3630eSHugh Dickins if (pgd_present(*pud)) /* Another has populated it */ 39175e541973SBenjamin Herrenschmidt pmd_free(mm, new); 39181bb3630eSHugh Dickins else 39191da177e4SLinus Torvalds pgd_populate(mm, pud, new); 39201da177e4SLinus Torvalds #endif /* __ARCH_HAS_4LEVEL_HACK */ 3921872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 39221bb3630eSHugh Dickins return 0; 39231da177e4SLinus Torvalds } 39241da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 39251da177e4SLinus Torvalds 39261da177e4SLinus Torvalds #if !defined(__HAVE_ARCH_GATE_AREA) 39271da177e4SLinus Torvalds 39281da177e4SLinus Torvalds #if defined(AT_SYSINFO_EHDR) 39295ce7852cSAdrian Bunk static struct vm_area_struct gate_vma; 39301da177e4SLinus Torvalds 39311da177e4SLinus Torvalds static int __init gate_vma_init(void) 39321da177e4SLinus Torvalds { 39331da177e4SLinus Torvalds gate_vma.vm_mm = NULL; 39341da177e4SLinus Torvalds gate_vma.vm_start = FIXADDR_USER_START; 39351da177e4SLinus Torvalds gate_vma.vm_end = FIXADDR_USER_END; 3936b6558c4aSRoland McGrath gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 3937b6558c4aSRoland McGrath gate_vma.vm_page_prot = __P101; 3938909af768SJason Baron 39391da177e4SLinus Torvalds return 0; 39401da177e4SLinus Torvalds } 39411da177e4SLinus Torvalds __initcall(gate_vma_init); 39421da177e4SLinus Torvalds #endif 39431da177e4SLinus Torvalds 394431db58b3SStephen Wilson struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 39451da177e4SLinus Torvalds { 39461da177e4SLinus Torvalds #ifdef AT_SYSINFO_EHDR 39471da177e4SLinus Torvalds return &gate_vma; 39481da177e4SLinus Torvalds #else 39491da177e4SLinus Torvalds return NULL; 39501da177e4SLinus Torvalds #endif 39511da177e4SLinus Torvalds } 39521da177e4SLinus Torvalds 3953cae5d390SStephen Wilson int in_gate_area_no_mm(unsigned long addr) 39541da177e4SLinus Torvalds { 39551da177e4SLinus Torvalds #ifdef AT_SYSINFO_EHDR 39561da177e4SLinus Torvalds if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 39571da177e4SLinus Torvalds return 1; 39581da177e4SLinus Torvalds #endif 39591da177e4SLinus Torvalds return 0; 39601da177e4SLinus Torvalds } 39611da177e4SLinus Torvalds 39621da177e4SLinus Torvalds #endif /* __HAVE_ARCH_GATE_AREA */ 39630ec76a11SDavid Howells 39641b36ba81SNamhyung Kim static int __follow_pte(struct mm_struct *mm, unsigned long address, 3965f8ad0f49SJohannes Weiner pte_t **ptepp, spinlock_t **ptlp) 3966f8ad0f49SJohannes Weiner { 3967f8ad0f49SJohannes Weiner pgd_t *pgd; 3968f8ad0f49SJohannes Weiner pud_t *pud; 3969f8ad0f49SJohannes Weiner pmd_t *pmd; 3970f8ad0f49SJohannes Weiner pte_t *ptep; 3971f8ad0f49SJohannes Weiner 3972f8ad0f49SJohannes Weiner pgd = pgd_offset(mm, address); 3973f8ad0f49SJohannes Weiner if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 3974f8ad0f49SJohannes Weiner goto out; 3975f8ad0f49SJohannes Weiner 3976f8ad0f49SJohannes Weiner pud = pud_offset(pgd, address); 3977f8ad0f49SJohannes Weiner if (pud_none(*pud) || unlikely(pud_bad(*pud))) 3978f8ad0f49SJohannes Weiner goto out; 3979f8ad0f49SJohannes Weiner 3980f8ad0f49SJohannes Weiner pmd = pmd_offset(pud, address); 3981f66055abSAndrea Arcangeli VM_BUG_ON(pmd_trans_huge(*pmd)); 3982f8ad0f49SJohannes Weiner if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 3983f8ad0f49SJohannes Weiner goto out; 3984f8ad0f49SJohannes Weiner 3985f8ad0f49SJohannes Weiner /* We cannot handle huge page PFN maps. Luckily they don't exist. */ 3986f8ad0f49SJohannes Weiner if (pmd_huge(*pmd)) 3987f8ad0f49SJohannes Weiner goto out; 3988f8ad0f49SJohannes Weiner 3989f8ad0f49SJohannes Weiner ptep = pte_offset_map_lock(mm, pmd, address, ptlp); 3990f8ad0f49SJohannes Weiner if (!ptep) 3991f8ad0f49SJohannes Weiner goto out; 3992f8ad0f49SJohannes Weiner if (!pte_present(*ptep)) 3993f8ad0f49SJohannes Weiner goto unlock; 3994f8ad0f49SJohannes Weiner *ptepp = ptep; 3995f8ad0f49SJohannes Weiner return 0; 3996f8ad0f49SJohannes Weiner unlock: 3997f8ad0f49SJohannes Weiner pte_unmap_unlock(ptep, *ptlp); 3998f8ad0f49SJohannes Weiner out: 3999f8ad0f49SJohannes Weiner return -EINVAL; 4000f8ad0f49SJohannes Weiner } 4001f8ad0f49SJohannes Weiner 40021b36ba81SNamhyung Kim static inline int follow_pte(struct mm_struct *mm, unsigned long address, 40031b36ba81SNamhyung Kim pte_t **ptepp, spinlock_t **ptlp) 40041b36ba81SNamhyung Kim { 40051b36ba81SNamhyung Kim int res; 40061b36ba81SNamhyung Kim 40071b36ba81SNamhyung Kim /* (void) is needed to make gcc happy */ 40081b36ba81SNamhyung Kim (void) __cond_lock(*ptlp, 40091b36ba81SNamhyung Kim !(res = __follow_pte(mm, address, ptepp, ptlp))); 40101b36ba81SNamhyung Kim return res; 40111b36ba81SNamhyung Kim } 40121b36ba81SNamhyung Kim 40133b6748e2SJohannes Weiner /** 40143b6748e2SJohannes Weiner * follow_pfn - look up PFN at a user virtual address 40153b6748e2SJohannes Weiner * @vma: memory mapping 40163b6748e2SJohannes Weiner * @address: user virtual address 40173b6748e2SJohannes Weiner * @pfn: location to store found PFN 40183b6748e2SJohannes Weiner * 40193b6748e2SJohannes Weiner * Only IO mappings and raw PFN mappings are allowed. 40203b6748e2SJohannes Weiner * 40213b6748e2SJohannes Weiner * Returns zero and the pfn at @pfn on success, -ve otherwise. 40223b6748e2SJohannes Weiner */ 40233b6748e2SJohannes Weiner int follow_pfn(struct vm_area_struct *vma, unsigned long address, 40243b6748e2SJohannes Weiner unsigned long *pfn) 40253b6748e2SJohannes Weiner { 40263b6748e2SJohannes Weiner int ret = -EINVAL; 40273b6748e2SJohannes Weiner spinlock_t *ptl; 40283b6748e2SJohannes Weiner pte_t *ptep; 40293b6748e2SJohannes Weiner 40303b6748e2SJohannes Weiner if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 40313b6748e2SJohannes Weiner return ret; 40323b6748e2SJohannes Weiner 40333b6748e2SJohannes Weiner ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); 40343b6748e2SJohannes Weiner if (ret) 40353b6748e2SJohannes Weiner return ret; 40363b6748e2SJohannes Weiner *pfn = pte_pfn(*ptep); 40373b6748e2SJohannes Weiner pte_unmap_unlock(ptep, ptl); 40383b6748e2SJohannes Weiner return 0; 40393b6748e2SJohannes Weiner } 40403b6748e2SJohannes Weiner EXPORT_SYMBOL(follow_pfn); 40413b6748e2SJohannes Weiner 404228b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 4043d87fe660Svenkatesh.pallipadi@intel.com int follow_phys(struct vm_area_struct *vma, 404428b2ee20SRik van Riel unsigned long address, unsigned int flags, 4045d87fe660Svenkatesh.pallipadi@intel.com unsigned long *prot, resource_size_t *phys) 404628b2ee20SRik van Riel { 404703668a4dSJohannes Weiner int ret = -EINVAL; 404828b2ee20SRik van Riel pte_t *ptep, pte; 404928b2ee20SRik van Riel spinlock_t *ptl; 405028b2ee20SRik van Riel 4051d87fe660Svenkatesh.pallipadi@intel.com if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 4052d87fe660Svenkatesh.pallipadi@intel.com goto out; 405328b2ee20SRik van Riel 405403668a4dSJohannes Weiner if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) 4055d87fe660Svenkatesh.pallipadi@intel.com goto out; 405628b2ee20SRik van Riel pte = *ptep; 405703668a4dSJohannes Weiner 405828b2ee20SRik van Riel if ((flags & FOLL_WRITE) && !pte_write(pte)) 405928b2ee20SRik van Riel goto unlock; 406028b2ee20SRik van Riel 406128b2ee20SRik van Riel *prot = pgprot_val(pte_pgprot(pte)); 406203668a4dSJohannes Weiner *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; 406328b2ee20SRik van Riel 406403668a4dSJohannes Weiner ret = 0; 406528b2ee20SRik van Riel unlock: 406628b2ee20SRik van Riel pte_unmap_unlock(ptep, ptl); 406728b2ee20SRik van Riel out: 4068d87fe660Svenkatesh.pallipadi@intel.com return ret; 406928b2ee20SRik van Riel } 407028b2ee20SRik van Riel 407128b2ee20SRik van Riel int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 407228b2ee20SRik van Riel void *buf, int len, int write) 407328b2ee20SRik van Riel { 407428b2ee20SRik van Riel resource_size_t phys_addr; 407528b2ee20SRik van Riel unsigned long prot = 0; 40762bc7273bSKOSAKI Motohiro void __iomem *maddr; 407728b2ee20SRik van Riel int offset = addr & (PAGE_SIZE-1); 407828b2ee20SRik van Riel 4079d87fe660Svenkatesh.pallipadi@intel.com if (follow_phys(vma, addr, write, &prot, &phys_addr)) 408028b2ee20SRik van Riel return -EINVAL; 408128b2ee20SRik van Riel 408228b2ee20SRik van Riel maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); 408328b2ee20SRik van Riel if (write) 408428b2ee20SRik van Riel memcpy_toio(maddr + offset, buf, len); 408528b2ee20SRik van Riel else 408628b2ee20SRik van Riel memcpy_fromio(buf, maddr + offset, len); 408728b2ee20SRik van Riel iounmap(maddr); 408828b2ee20SRik van Riel 408928b2ee20SRik van Riel return len; 409028b2ee20SRik van Riel } 40915a73633eSUwe Kleine-König EXPORT_SYMBOL_GPL(generic_access_phys); 409228b2ee20SRik van Riel #endif 409328b2ee20SRik van Riel 40940ec76a11SDavid Howells /* 4095206cb636SStephen Wilson * Access another process' address space as given in mm. If non-NULL, use the 4096206cb636SStephen Wilson * given task for page fault accounting. 40970ec76a11SDavid Howells */ 4098206cb636SStephen Wilson static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, 4099206cb636SStephen Wilson unsigned long addr, void *buf, int len, int write) 41000ec76a11SDavid Howells { 41010ec76a11SDavid Howells struct vm_area_struct *vma; 41020ec76a11SDavid Howells void *old_buf = buf; 41030ec76a11SDavid Howells 41040ec76a11SDavid Howells down_read(&mm->mmap_sem); 4105183ff22bSSimon Arlott /* ignore errors, just check how much was successfully transferred */ 41060ec76a11SDavid Howells while (len) { 41070ec76a11SDavid Howells int bytes, ret, offset; 41080ec76a11SDavid Howells void *maddr; 410928b2ee20SRik van Riel struct page *page = NULL; 41100ec76a11SDavid Howells 41110ec76a11SDavid Howells ret = get_user_pages(tsk, mm, addr, 1, 41120ec76a11SDavid Howells write, 1, &page, &vma); 411328b2ee20SRik van Riel if (ret <= 0) { 411428b2ee20SRik van Riel /* 411528b2ee20SRik van Riel * Check if this is a VM_IO | VM_PFNMAP VMA, which 411628b2ee20SRik van Riel * we can access using slightly different code. 411728b2ee20SRik van Riel */ 411828b2ee20SRik van Riel #ifdef CONFIG_HAVE_IOREMAP_PROT 411928b2ee20SRik van Riel vma = find_vma(mm, addr); 4120fe936dfcSMichael Ellerman if (!vma || vma->vm_start > addr) 41210ec76a11SDavid Howells break; 412228b2ee20SRik van Riel if (vma->vm_ops && vma->vm_ops->access) 412328b2ee20SRik van Riel ret = vma->vm_ops->access(vma, addr, buf, 412428b2ee20SRik van Riel len, write); 412528b2ee20SRik van Riel if (ret <= 0) 412628b2ee20SRik van Riel #endif 412728b2ee20SRik van Riel break; 412828b2ee20SRik van Riel bytes = ret; 412928b2ee20SRik van Riel } else { 41300ec76a11SDavid Howells bytes = len; 41310ec76a11SDavid Howells offset = addr & (PAGE_SIZE-1); 41320ec76a11SDavid Howells if (bytes > PAGE_SIZE-offset) 41330ec76a11SDavid Howells bytes = PAGE_SIZE-offset; 41340ec76a11SDavid Howells 41350ec76a11SDavid Howells maddr = kmap(page); 41360ec76a11SDavid Howells if (write) { 41370ec76a11SDavid Howells copy_to_user_page(vma, page, addr, 41380ec76a11SDavid Howells maddr + offset, buf, bytes); 41390ec76a11SDavid Howells set_page_dirty_lock(page); 41400ec76a11SDavid Howells } else { 41410ec76a11SDavid Howells copy_from_user_page(vma, page, addr, 41420ec76a11SDavid Howells buf, maddr + offset, bytes); 41430ec76a11SDavid Howells } 41440ec76a11SDavid Howells kunmap(page); 41450ec76a11SDavid Howells page_cache_release(page); 414628b2ee20SRik van Riel } 41470ec76a11SDavid Howells len -= bytes; 41480ec76a11SDavid Howells buf += bytes; 41490ec76a11SDavid Howells addr += bytes; 41500ec76a11SDavid Howells } 41510ec76a11SDavid Howells up_read(&mm->mmap_sem); 41520ec76a11SDavid Howells 41530ec76a11SDavid Howells return buf - old_buf; 41540ec76a11SDavid Howells } 415503252919SAndi Kleen 41565ddd36b9SStephen Wilson /** 4157ae91dbfcSRandy Dunlap * access_remote_vm - access another process' address space 41585ddd36b9SStephen Wilson * @mm: the mm_struct of the target address space 41595ddd36b9SStephen Wilson * @addr: start address to access 41605ddd36b9SStephen Wilson * @buf: source or destination buffer 41615ddd36b9SStephen Wilson * @len: number of bytes to transfer 41625ddd36b9SStephen Wilson * @write: whether the access is a write 41635ddd36b9SStephen Wilson * 41645ddd36b9SStephen Wilson * The caller must hold a reference on @mm. 41655ddd36b9SStephen Wilson */ 41665ddd36b9SStephen Wilson int access_remote_vm(struct mm_struct *mm, unsigned long addr, 41675ddd36b9SStephen Wilson void *buf, int len, int write) 41685ddd36b9SStephen Wilson { 41695ddd36b9SStephen Wilson return __access_remote_vm(NULL, mm, addr, buf, len, write); 41705ddd36b9SStephen Wilson } 41715ddd36b9SStephen Wilson 417203252919SAndi Kleen /* 4173206cb636SStephen Wilson * Access another process' address space. 4174206cb636SStephen Wilson * Source/target buffer must be kernel space, 4175206cb636SStephen Wilson * Do not walk the page table directly, use get_user_pages 4176206cb636SStephen Wilson */ 4177206cb636SStephen Wilson int access_process_vm(struct task_struct *tsk, unsigned long addr, 4178206cb636SStephen Wilson void *buf, int len, int write) 4179206cb636SStephen Wilson { 4180206cb636SStephen Wilson struct mm_struct *mm; 4181206cb636SStephen Wilson int ret; 4182206cb636SStephen Wilson 4183206cb636SStephen Wilson mm = get_task_mm(tsk); 4184206cb636SStephen Wilson if (!mm) 4185206cb636SStephen Wilson return 0; 4186206cb636SStephen Wilson 4187206cb636SStephen Wilson ret = __access_remote_vm(tsk, mm, addr, buf, len, write); 4188206cb636SStephen Wilson mmput(mm); 4189206cb636SStephen Wilson 4190206cb636SStephen Wilson return ret; 4191206cb636SStephen Wilson } 4192206cb636SStephen Wilson 419303252919SAndi Kleen /* 419403252919SAndi Kleen * Print the name of a VMA. 419503252919SAndi Kleen */ 419603252919SAndi Kleen void print_vma_addr(char *prefix, unsigned long ip) 419703252919SAndi Kleen { 419803252919SAndi Kleen struct mm_struct *mm = current->mm; 419903252919SAndi Kleen struct vm_area_struct *vma; 420003252919SAndi Kleen 4201e8bff74aSIngo Molnar /* 4202e8bff74aSIngo Molnar * Do not print if we are in atomic 4203e8bff74aSIngo Molnar * contexts (in exception stacks, etc.): 4204e8bff74aSIngo Molnar */ 4205e8bff74aSIngo Molnar if (preempt_count()) 4206e8bff74aSIngo Molnar return; 4207e8bff74aSIngo Molnar 420803252919SAndi Kleen down_read(&mm->mmap_sem); 420903252919SAndi Kleen vma = find_vma(mm, ip); 421003252919SAndi Kleen if (vma && vma->vm_file) { 421103252919SAndi Kleen struct file *f = vma->vm_file; 421203252919SAndi Kleen char *buf = (char *)__get_free_page(GFP_KERNEL); 421303252919SAndi Kleen if (buf) { 42142fbc57c5SAndy Shevchenko char *p; 421503252919SAndi Kleen 4216cf28b486SJan Blunck p = d_path(&f->f_path, buf, PAGE_SIZE); 421703252919SAndi Kleen if (IS_ERR(p)) 421803252919SAndi Kleen p = "?"; 42192fbc57c5SAndy Shevchenko printk("%s%s[%lx+%lx]", prefix, kbasename(p), 422003252919SAndi Kleen vma->vm_start, 422103252919SAndi Kleen vma->vm_end - vma->vm_start); 422203252919SAndi Kleen free_page((unsigned long)buf); 422303252919SAndi Kleen } 422403252919SAndi Kleen } 422551a07e50SJeff Liu up_read(&mm->mmap_sem); 422603252919SAndi Kleen } 42273ee1afa3SNick Piggin 4228662bbcb2SMichael S. Tsirkin #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) 42293ee1afa3SNick Piggin void might_fault(void) 42303ee1afa3SNick Piggin { 423195156f00SPeter Zijlstra /* 423295156f00SPeter Zijlstra * Some code (nfs/sunrpc) uses socket ops on kernel memory while 423395156f00SPeter Zijlstra * holding the mmap_sem, this is safe because kernel memory doesn't 423495156f00SPeter Zijlstra * get paged out, therefore we'll never actually fault, and the 423595156f00SPeter Zijlstra * below annotations will generate false positives. 423695156f00SPeter Zijlstra */ 423795156f00SPeter Zijlstra if (segment_eq(get_fs(), KERNEL_DS)) 423895156f00SPeter Zijlstra return; 423995156f00SPeter Zijlstra 42403ee1afa3SNick Piggin /* 42413ee1afa3SNick Piggin * it would be nicer only to annotate paths which are not under 42423ee1afa3SNick Piggin * pagefault_disable, however that requires a larger audit and 42433ee1afa3SNick Piggin * providing helpers like get_user_atomic. 42443ee1afa3SNick Piggin */ 4245662bbcb2SMichael S. Tsirkin if (in_atomic()) 4246662bbcb2SMichael S. Tsirkin return; 4247662bbcb2SMichael S. Tsirkin 4248662bbcb2SMichael S. Tsirkin __might_sleep(__FILE__, __LINE__, 0); 4249662bbcb2SMichael S. Tsirkin 4250662bbcb2SMichael S. Tsirkin if (current->mm) 42513ee1afa3SNick Piggin might_lock_read(¤t->mm->mmap_sem); 42523ee1afa3SNick Piggin } 42533ee1afa3SNick Piggin EXPORT_SYMBOL(might_fault); 42543ee1afa3SNick Piggin #endif 425547ad8475SAndrea Arcangeli 425647ad8475SAndrea Arcangeli #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) 425747ad8475SAndrea Arcangeli static void clear_gigantic_page(struct page *page, 425847ad8475SAndrea Arcangeli unsigned long addr, 425947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 426047ad8475SAndrea Arcangeli { 426147ad8475SAndrea Arcangeli int i; 426247ad8475SAndrea Arcangeli struct page *p = page; 426347ad8475SAndrea Arcangeli 426447ad8475SAndrea Arcangeli might_sleep(); 426547ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; 426647ad8475SAndrea Arcangeli i++, p = mem_map_next(p, page, i)) { 426747ad8475SAndrea Arcangeli cond_resched(); 426847ad8475SAndrea Arcangeli clear_user_highpage(p, addr + i * PAGE_SIZE); 426947ad8475SAndrea Arcangeli } 427047ad8475SAndrea Arcangeli } 427147ad8475SAndrea Arcangeli void clear_huge_page(struct page *page, 427247ad8475SAndrea Arcangeli unsigned long addr, unsigned int pages_per_huge_page) 427347ad8475SAndrea Arcangeli { 427447ad8475SAndrea Arcangeli int i; 427547ad8475SAndrea Arcangeli 427647ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 427747ad8475SAndrea Arcangeli clear_gigantic_page(page, addr, pages_per_huge_page); 427847ad8475SAndrea Arcangeli return; 427947ad8475SAndrea Arcangeli } 428047ad8475SAndrea Arcangeli 428147ad8475SAndrea Arcangeli might_sleep(); 428247ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; i++) { 428347ad8475SAndrea Arcangeli cond_resched(); 428447ad8475SAndrea Arcangeli clear_user_highpage(page + i, addr + i * PAGE_SIZE); 428547ad8475SAndrea Arcangeli } 428647ad8475SAndrea Arcangeli } 428747ad8475SAndrea Arcangeli 428847ad8475SAndrea Arcangeli static void copy_user_gigantic_page(struct page *dst, struct page *src, 428947ad8475SAndrea Arcangeli unsigned long addr, 429047ad8475SAndrea Arcangeli struct vm_area_struct *vma, 429147ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 429247ad8475SAndrea Arcangeli { 429347ad8475SAndrea Arcangeli int i; 429447ad8475SAndrea Arcangeli struct page *dst_base = dst; 429547ad8475SAndrea Arcangeli struct page *src_base = src; 429647ad8475SAndrea Arcangeli 429747ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; ) { 429847ad8475SAndrea Arcangeli cond_resched(); 429947ad8475SAndrea Arcangeli copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 430047ad8475SAndrea Arcangeli 430147ad8475SAndrea Arcangeli i++; 430247ad8475SAndrea Arcangeli dst = mem_map_next(dst, dst_base, i); 430347ad8475SAndrea Arcangeli src = mem_map_next(src, src_base, i); 430447ad8475SAndrea Arcangeli } 430547ad8475SAndrea Arcangeli } 430647ad8475SAndrea Arcangeli 430747ad8475SAndrea Arcangeli void copy_user_huge_page(struct page *dst, struct page *src, 430847ad8475SAndrea Arcangeli unsigned long addr, struct vm_area_struct *vma, 430947ad8475SAndrea Arcangeli unsigned int pages_per_huge_page) 431047ad8475SAndrea Arcangeli { 431147ad8475SAndrea Arcangeli int i; 431247ad8475SAndrea Arcangeli 431347ad8475SAndrea Arcangeli if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { 431447ad8475SAndrea Arcangeli copy_user_gigantic_page(dst, src, addr, vma, 431547ad8475SAndrea Arcangeli pages_per_huge_page); 431647ad8475SAndrea Arcangeli return; 431747ad8475SAndrea Arcangeli } 431847ad8475SAndrea Arcangeli 431947ad8475SAndrea Arcangeli might_sleep(); 432047ad8475SAndrea Arcangeli for (i = 0; i < pages_per_huge_page; i++) { 432147ad8475SAndrea Arcangeli cond_resched(); 432247ad8475SAndrea Arcangeli copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 432347ad8475SAndrea Arcangeli } 432447ad8475SAndrea Arcangeli } 432547ad8475SAndrea Arcangeli #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ 4326