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> 481da177e4SLinus Torvalds #include <linux/rmap.h> 491da177e4SLinus Torvalds #include <linux/module.h> 501da177e4SLinus Torvalds #include <linux/init.h> 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds #include <asm/pgalloc.h> 531da177e4SLinus Torvalds #include <asm/uaccess.h> 541da177e4SLinus Torvalds #include <asm/tlb.h> 551da177e4SLinus Torvalds #include <asm/tlbflush.h> 561da177e4SLinus Torvalds #include <asm/pgtable.h> 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds #include <linux/swapops.h> 591da177e4SLinus Torvalds #include <linux/elf.h> 601da177e4SLinus Torvalds 61d41dee36SAndy Whitcroft #ifndef CONFIG_NEED_MULTIPLE_NODES 621da177e4SLinus Torvalds /* use the per-pgdat data instead for discontigmem - mbligh */ 631da177e4SLinus Torvalds unsigned long max_mapnr; 641da177e4SLinus Torvalds struct page *mem_map; 651da177e4SLinus Torvalds 661da177e4SLinus Torvalds EXPORT_SYMBOL(max_mapnr); 671da177e4SLinus Torvalds EXPORT_SYMBOL(mem_map); 681da177e4SLinus Torvalds #endif 691da177e4SLinus Torvalds 701da177e4SLinus Torvalds unsigned long num_physpages; 711da177e4SLinus Torvalds /* 721da177e4SLinus Torvalds * A number of key systems in x86 including ioremap() rely on the assumption 731da177e4SLinus Torvalds * that high_memory defines the upper bound on direct map memory, then end 741da177e4SLinus Torvalds * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 751da177e4SLinus Torvalds * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 761da177e4SLinus Torvalds * and ZONE_HIGHMEM. 771da177e4SLinus Torvalds */ 781da177e4SLinus Torvalds void * high_memory; 791da177e4SLinus Torvalds unsigned long vmalloc_earlyreserve; 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds EXPORT_SYMBOL(num_physpages); 821da177e4SLinus Torvalds EXPORT_SYMBOL(high_memory); 831da177e4SLinus Torvalds EXPORT_SYMBOL(vmalloc_earlyreserve); 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds /* 861da177e4SLinus Torvalds * If a p?d_bad entry is found while walking page tables, report 871da177e4SLinus Torvalds * the error, before resetting entry to p?d_none. Usually (but 881da177e4SLinus Torvalds * very seldom) called out from the p?d_none_or_clear_bad macros. 891da177e4SLinus Torvalds */ 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds void pgd_clear_bad(pgd_t *pgd) 921da177e4SLinus Torvalds { 931da177e4SLinus Torvalds pgd_ERROR(*pgd); 941da177e4SLinus Torvalds pgd_clear(pgd); 951da177e4SLinus Torvalds } 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds void pud_clear_bad(pud_t *pud) 981da177e4SLinus Torvalds { 991da177e4SLinus Torvalds pud_ERROR(*pud); 1001da177e4SLinus Torvalds pud_clear(pud); 1011da177e4SLinus Torvalds } 1021da177e4SLinus Torvalds 1031da177e4SLinus Torvalds void pmd_clear_bad(pmd_t *pmd) 1041da177e4SLinus Torvalds { 1051da177e4SLinus Torvalds pmd_ERROR(*pmd); 1061da177e4SLinus Torvalds pmd_clear(pmd); 1071da177e4SLinus Torvalds } 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds /* 1101da177e4SLinus Torvalds * Note: this doesn't free the actual pages themselves. That 1111da177e4SLinus Torvalds * has been handled earlier when unmapping all the memory regions. 1121da177e4SLinus Torvalds */ 113e0da382cSHugh Dickins static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) 1141da177e4SLinus Torvalds { 1151da177e4SLinus Torvalds struct page *page = pmd_page(*pmd); 1161da177e4SLinus Torvalds pmd_clear(pmd); 1174c21e2f2SHugh Dickins pte_lock_deinit(page); 118e0da382cSHugh Dickins pte_free_tlb(tlb, page); 1191da177e4SLinus Torvalds dec_page_state(nr_page_table_pages); 1201da177e4SLinus Torvalds tlb->mm->nr_ptes--; 1211da177e4SLinus Torvalds } 1221da177e4SLinus Torvalds 123e0da382cSHugh Dickins static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 124e0da382cSHugh Dickins unsigned long addr, unsigned long end, 125e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 1261da177e4SLinus Torvalds { 1271da177e4SLinus Torvalds pmd_t *pmd; 1281da177e4SLinus Torvalds unsigned long next; 129e0da382cSHugh Dickins unsigned long start; 1301da177e4SLinus Torvalds 131e0da382cSHugh Dickins start = addr; 1321da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 1331da177e4SLinus Torvalds do { 1341da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 1351da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 1361da177e4SLinus Torvalds continue; 137e0da382cSHugh Dickins free_pte_range(tlb, pmd); 1381da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 1391da177e4SLinus Torvalds 140e0da382cSHugh Dickins start &= PUD_MASK; 141e0da382cSHugh Dickins if (start < floor) 142e0da382cSHugh Dickins return; 143e0da382cSHugh Dickins if (ceiling) { 144e0da382cSHugh Dickins ceiling &= PUD_MASK; 145e0da382cSHugh Dickins if (!ceiling) 146e0da382cSHugh Dickins return; 1471da177e4SLinus Torvalds } 148e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 149e0da382cSHugh Dickins return; 150e0da382cSHugh Dickins 151e0da382cSHugh Dickins pmd = pmd_offset(pud, start); 152e0da382cSHugh Dickins pud_clear(pud); 153e0da382cSHugh Dickins pmd_free_tlb(tlb, pmd); 1541da177e4SLinus Torvalds } 1551da177e4SLinus Torvalds 156e0da382cSHugh Dickins static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 157e0da382cSHugh Dickins unsigned long addr, unsigned long end, 158e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 1591da177e4SLinus Torvalds { 1601da177e4SLinus Torvalds pud_t *pud; 1611da177e4SLinus Torvalds unsigned long next; 162e0da382cSHugh Dickins unsigned long start; 1631da177e4SLinus Torvalds 164e0da382cSHugh Dickins start = addr; 1651da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 1661da177e4SLinus Torvalds do { 1671da177e4SLinus Torvalds next = pud_addr_end(addr, end); 1681da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 1691da177e4SLinus Torvalds continue; 170e0da382cSHugh Dickins free_pmd_range(tlb, pud, addr, next, floor, ceiling); 1711da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 1721da177e4SLinus Torvalds 173e0da382cSHugh Dickins start &= PGDIR_MASK; 174e0da382cSHugh Dickins if (start < floor) 175e0da382cSHugh Dickins return; 176e0da382cSHugh Dickins if (ceiling) { 177e0da382cSHugh Dickins ceiling &= PGDIR_MASK; 178e0da382cSHugh Dickins if (!ceiling) 179e0da382cSHugh Dickins return; 1801da177e4SLinus Torvalds } 181e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 182e0da382cSHugh Dickins return; 183e0da382cSHugh Dickins 184e0da382cSHugh Dickins pud = pud_offset(pgd, start); 185e0da382cSHugh Dickins pgd_clear(pgd); 186e0da382cSHugh Dickins pud_free_tlb(tlb, pud); 1871da177e4SLinus Torvalds } 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds /* 190e0da382cSHugh Dickins * This function frees user-level page tables of a process. 191e0da382cSHugh Dickins * 1921da177e4SLinus Torvalds * Must be called with pagetable lock held. 1931da177e4SLinus Torvalds */ 1943bf5ee95SHugh Dickins void free_pgd_range(struct mmu_gather **tlb, 195e0da382cSHugh Dickins unsigned long addr, unsigned long end, 196e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 1971da177e4SLinus Torvalds { 1981da177e4SLinus Torvalds pgd_t *pgd; 1991da177e4SLinus Torvalds unsigned long next; 200e0da382cSHugh Dickins unsigned long start; 2011da177e4SLinus Torvalds 202e0da382cSHugh Dickins /* 203e0da382cSHugh Dickins * The next few lines have given us lots of grief... 204e0da382cSHugh Dickins * 205e0da382cSHugh Dickins * Why are we testing PMD* at this top level? Because often 206e0da382cSHugh Dickins * there will be no work to do at all, and we'd prefer not to 207e0da382cSHugh Dickins * go all the way down to the bottom just to discover that. 208e0da382cSHugh Dickins * 209e0da382cSHugh Dickins * Why all these "- 1"s? Because 0 represents both the bottom 210e0da382cSHugh Dickins * of the address space and the top of it (using -1 for the 211e0da382cSHugh Dickins * top wouldn't help much: the masks would do the wrong thing). 212e0da382cSHugh Dickins * The rule is that addr 0 and floor 0 refer to the bottom of 213e0da382cSHugh Dickins * the address space, but end 0 and ceiling 0 refer to the top 214e0da382cSHugh Dickins * Comparisons need to use "end - 1" and "ceiling - 1" (though 215e0da382cSHugh Dickins * that end 0 case should be mythical). 216e0da382cSHugh Dickins * 217e0da382cSHugh Dickins * Wherever addr is brought up or ceiling brought down, we must 218e0da382cSHugh Dickins * be careful to reject "the opposite 0" before it confuses the 219e0da382cSHugh Dickins * subsequent tests. But what about where end is brought down 220e0da382cSHugh Dickins * by PMD_SIZE below? no, end can't go down to 0 there. 221e0da382cSHugh Dickins * 222e0da382cSHugh Dickins * Whereas we round start (addr) and ceiling down, by different 223e0da382cSHugh Dickins * masks at different levels, in order to test whether a table 224e0da382cSHugh Dickins * now has no other vmas using it, so can be freed, we don't 225e0da382cSHugh Dickins * bother to round floor or end up - the tests don't need that. 226e0da382cSHugh Dickins */ 227e0da382cSHugh Dickins 228e0da382cSHugh Dickins addr &= PMD_MASK; 229e0da382cSHugh Dickins if (addr < floor) { 230e0da382cSHugh Dickins addr += PMD_SIZE; 231e0da382cSHugh Dickins if (!addr) 232e0da382cSHugh Dickins return; 233e0da382cSHugh Dickins } 234e0da382cSHugh Dickins if (ceiling) { 235e0da382cSHugh Dickins ceiling &= PMD_MASK; 236e0da382cSHugh Dickins if (!ceiling) 237e0da382cSHugh Dickins return; 238e0da382cSHugh Dickins } 239e0da382cSHugh Dickins if (end - 1 > ceiling - 1) 240e0da382cSHugh Dickins end -= PMD_SIZE; 241e0da382cSHugh Dickins if (addr > end - 1) 242e0da382cSHugh Dickins return; 243e0da382cSHugh Dickins 244e0da382cSHugh Dickins start = addr; 2453bf5ee95SHugh Dickins pgd = pgd_offset((*tlb)->mm, addr); 2461da177e4SLinus Torvalds do { 2471da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 2481da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 2491da177e4SLinus Torvalds continue; 2503bf5ee95SHugh Dickins free_pud_range(*tlb, pgd, addr, next, floor, ceiling); 2511da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 252e0da382cSHugh Dickins 2534d6ddfa9SHugh Dickins if (!(*tlb)->fullmm) 2543bf5ee95SHugh Dickins flush_tlb_pgtables((*tlb)->mm, start, end); 255e0da382cSHugh Dickins } 256e0da382cSHugh Dickins 257e0da382cSHugh Dickins void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, 258e0da382cSHugh Dickins unsigned long floor, unsigned long ceiling) 259e0da382cSHugh Dickins { 260e0da382cSHugh Dickins while (vma) { 261e0da382cSHugh Dickins struct vm_area_struct *next = vma->vm_next; 262e0da382cSHugh Dickins unsigned long addr = vma->vm_start; 263e0da382cSHugh Dickins 2648f4f8c16SHugh Dickins /* 2658f4f8c16SHugh Dickins * Hide vma from rmap and vmtruncate before freeing pgtables 2668f4f8c16SHugh Dickins */ 2678f4f8c16SHugh Dickins anon_vma_unlink(vma); 2688f4f8c16SHugh Dickins unlink_file_vma(vma); 2698f4f8c16SHugh Dickins 2703bf5ee95SHugh Dickins if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) { 2713bf5ee95SHugh Dickins hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 2723bf5ee95SHugh Dickins floor, next? next->vm_start: ceiling); 2733bf5ee95SHugh Dickins } else { 2743bf5ee95SHugh Dickins /* 2753bf5ee95SHugh Dickins * Optimization: gather nearby vmas into one call down 2763bf5ee95SHugh Dickins */ 2773bf5ee95SHugh Dickins while (next && next->vm_start <= vma->vm_end + PMD_SIZE 2783bf5ee95SHugh Dickins && !is_hugepage_only_range(vma->vm_mm, next->vm_start, 2793bf5ee95SHugh Dickins HPAGE_SIZE)) { 280e0da382cSHugh Dickins vma = next; 281e0da382cSHugh Dickins next = vma->vm_next; 2828f4f8c16SHugh Dickins anon_vma_unlink(vma); 2838f4f8c16SHugh Dickins unlink_file_vma(vma); 284e0da382cSHugh Dickins } 2853bf5ee95SHugh Dickins free_pgd_range(tlb, addr, vma->vm_end, 286e0da382cSHugh Dickins floor, next? next->vm_start: ceiling); 2873bf5ee95SHugh Dickins } 288e0da382cSHugh Dickins vma = next; 289e0da382cSHugh Dickins } 2901da177e4SLinus Torvalds } 2911da177e4SLinus Torvalds 2921bb3630eSHugh Dickins int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) 2931da177e4SLinus Torvalds { 294c74df32cSHugh Dickins struct page *new = pte_alloc_one(mm, address); 2951da177e4SLinus Torvalds if (!new) 2961bb3630eSHugh Dickins return -ENOMEM; 2971bb3630eSHugh Dickins 2984c21e2f2SHugh Dickins pte_lock_init(new); 299c74df32cSHugh Dickins spin_lock(&mm->page_table_lock); 3004c21e2f2SHugh Dickins if (pmd_present(*pmd)) { /* Another has populated it */ 3014c21e2f2SHugh Dickins pte_lock_deinit(new); 3021da177e4SLinus Torvalds pte_free(new); 3034c21e2f2SHugh Dickins } else { 3041da177e4SLinus Torvalds mm->nr_ptes++; 3051da177e4SLinus Torvalds inc_page_state(nr_page_table_pages); 3061da177e4SLinus Torvalds pmd_populate(mm, pmd, new); 3071da177e4SLinus Torvalds } 308c74df32cSHugh Dickins spin_unlock(&mm->page_table_lock); 3091bb3630eSHugh Dickins return 0; 3101da177e4SLinus Torvalds } 3111da177e4SLinus Torvalds 3121bb3630eSHugh Dickins int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) 3131da177e4SLinus Torvalds { 3141bb3630eSHugh Dickins pte_t *new = pte_alloc_one_kernel(&init_mm, address); 3151da177e4SLinus Torvalds if (!new) 3161bb3630eSHugh Dickins return -ENOMEM; 3171da177e4SLinus Torvalds 318872fec16SHugh Dickins spin_lock(&init_mm.page_table_lock); 3191bb3630eSHugh Dickins if (pmd_present(*pmd)) /* Another has populated it */ 3201da177e4SLinus Torvalds pte_free_kernel(new); 321872fec16SHugh Dickins else 322872fec16SHugh Dickins pmd_populate_kernel(&init_mm, pmd, new); 323872fec16SHugh Dickins spin_unlock(&init_mm.page_table_lock); 3241bb3630eSHugh Dickins return 0; 3251da177e4SLinus Torvalds } 3261da177e4SLinus Torvalds 327ae859762SHugh Dickins static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) 328ae859762SHugh Dickins { 329ae859762SHugh Dickins if (file_rss) 330ae859762SHugh Dickins add_mm_counter(mm, file_rss, file_rss); 331ae859762SHugh Dickins if (anon_rss) 332ae859762SHugh Dickins add_mm_counter(mm, anon_rss, anon_rss); 333ae859762SHugh Dickins } 334ae859762SHugh Dickins 3351da177e4SLinus Torvalds /* 336b5810039SNick Piggin * This function is called to print an error when a pte in a 337b5810039SNick Piggin * !VM_RESERVED region is found pointing to an invalid pfn (which 338b5810039SNick Piggin * is an error. 339b5810039SNick Piggin * 340b5810039SNick Piggin * The calling function must still handle the error. 341b5810039SNick Piggin */ 342b5810039SNick Piggin void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) 343b5810039SNick Piggin { 344b5810039SNick Piggin printk(KERN_ERR "Bad pte = %08llx, process = %s, " 345b5810039SNick Piggin "vm_flags = %lx, vaddr = %lx\n", 346b5810039SNick Piggin (long long)pte_val(pte), 347b5810039SNick Piggin (vma->vm_mm == current->mm ? current->comm : "???"), 348b5810039SNick Piggin vma->vm_flags, vaddr); 349b5810039SNick Piggin dump_stack(); 350b5810039SNick Piggin } 351b5810039SNick Piggin 352b5810039SNick Piggin /* 3531da177e4SLinus Torvalds * copy one vm_area from one task to the other. Assumes the page tables 3541da177e4SLinus Torvalds * already present in the new task to be cleared in the whole range 3551da177e4SLinus Torvalds * covered by this vma. 3561da177e4SLinus Torvalds */ 3571da177e4SLinus Torvalds 3588c103762SHugh Dickins static inline void 3591da177e4SLinus Torvalds copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 360b5810039SNick Piggin pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 3618c103762SHugh Dickins unsigned long addr, int *rss) 3621da177e4SLinus Torvalds { 363b5810039SNick Piggin unsigned long vm_flags = vma->vm_flags; 3641da177e4SLinus Torvalds pte_t pte = *src_pte; 3651da177e4SLinus Torvalds struct page *page; 3661da177e4SLinus Torvalds unsigned long pfn; 3671da177e4SLinus Torvalds 3681da177e4SLinus Torvalds /* pte contains position in swap or file, so copy. */ 3691da177e4SLinus Torvalds if (unlikely(!pte_present(pte))) { 3701da177e4SLinus Torvalds if (!pte_file(pte)) { 3711da177e4SLinus Torvalds swap_duplicate(pte_to_swp_entry(pte)); 3721da177e4SLinus Torvalds /* make sure dst_mm is on swapoff's mmlist. */ 3731da177e4SLinus Torvalds if (unlikely(list_empty(&dst_mm->mmlist))) { 3741da177e4SLinus Torvalds spin_lock(&mmlist_lock); 375f412ac08SHugh Dickins if (list_empty(&dst_mm->mmlist)) 376f412ac08SHugh Dickins list_add(&dst_mm->mmlist, 377f412ac08SHugh Dickins &src_mm->mmlist); 3781da177e4SLinus Torvalds spin_unlock(&mmlist_lock); 3791da177e4SLinus Torvalds } 3801da177e4SLinus Torvalds } 381ae859762SHugh Dickins goto out_set_pte; 3821da177e4SLinus Torvalds } 3831da177e4SLinus Torvalds 384b5810039SNick Piggin /* If the region is VM_RESERVED, the mapping is not 385b5810039SNick Piggin * mapped via rmap - duplicate the pte as is. 3861da177e4SLinus Torvalds */ 387b5810039SNick Piggin if (vm_flags & VM_RESERVED) 388ae859762SHugh Dickins goto out_set_pte; 3891da177e4SLinus Torvalds 390b5810039SNick Piggin pfn = pte_pfn(pte); 391b5810039SNick Piggin /* If the pte points outside of valid memory but 392b5810039SNick Piggin * the region is not VM_RESERVED, we have a problem. 393b5810039SNick Piggin */ 394b5810039SNick Piggin if (unlikely(!pfn_valid(pfn))) { 395b5810039SNick Piggin print_bad_pte(vma, pte, addr); 396b5810039SNick Piggin goto out_set_pte; /* try to do something sane */ 397b5810039SNick Piggin } 398b5810039SNick Piggin 399b5810039SNick Piggin page = pfn_to_page(pfn); 400b5810039SNick Piggin 4011da177e4SLinus Torvalds /* 4021da177e4SLinus Torvalds * If it's a COW mapping, write protect it both 4031da177e4SLinus Torvalds * in the parent and the child 4041da177e4SLinus Torvalds */ 4051da177e4SLinus Torvalds if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) { 4061da177e4SLinus Torvalds ptep_set_wrprotect(src_mm, addr, src_pte); 4071da177e4SLinus Torvalds pte = *src_pte; 4081da177e4SLinus Torvalds } 4091da177e4SLinus Torvalds 4101da177e4SLinus Torvalds /* 4111da177e4SLinus Torvalds * If it's a shared mapping, mark it clean in 4121da177e4SLinus Torvalds * the child 4131da177e4SLinus Torvalds */ 4141da177e4SLinus Torvalds if (vm_flags & VM_SHARED) 4151da177e4SLinus Torvalds pte = pte_mkclean(pte); 4161da177e4SLinus Torvalds pte = pte_mkold(pte); 4171da177e4SLinus Torvalds get_page(page); 4181da177e4SLinus Torvalds page_dup_rmap(page); 4198c103762SHugh Dickins rss[!!PageAnon(page)]++; 420ae859762SHugh Dickins 421ae859762SHugh Dickins out_set_pte: 422ae859762SHugh Dickins set_pte_at(dst_mm, addr, dst_pte, pte); 4231da177e4SLinus Torvalds } 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 4261da177e4SLinus Torvalds pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 4271da177e4SLinus Torvalds unsigned long addr, unsigned long end) 4281da177e4SLinus Torvalds { 4291da177e4SLinus Torvalds pte_t *src_pte, *dst_pte; 430c74df32cSHugh Dickins spinlock_t *src_ptl, *dst_ptl; 431e040f218SHugh Dickins int progress = 0; 4328c103762SHugh Dickins int rss[2]; 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds again: 435ae859762SHugh Dickins rss[1] = rss[0] = 0; 436c74df32cSHugh Dickins dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 4371da177e4SLinus Torvalds if (!dst_pte) 4381da177e4SLinus Torvalds return -ENOMEM; 4391da177e4SLinus Torvalds src_pte = pte_offset_map_nested(src_pmd, addr); 4404c21e2f2SHugh Dickins src_ptl = pte_lockptr(src_mm, src_pmd); 441c74df32cSHugh Dickins spin_lock(src_ptl); 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds do { 4441da177e4SLinus Torvalds /* 4451da177e4SLinus Torvalds * We are holding two locks at this point - either of them 4461da177e4SLinus Torvalds * could generate latencies in another task on another CPU. 4471da177e4SLinus Torvalds */ 448e040f218SHugh Dickins if (progress >= 32) { 449e040f218SHugh Dickins progress = 0; 450e040f218SHugh Dickins if (need_resched() || 451c74df32cSHugh Dickins need_lockbreak(src_ptl) || 452c74df32cSHugh Dickins need_lockbreak(dst_ptl)) 4531da177e4SLinus Torvalds break; 454e040f218SHugh Dickins } 4551da177e4SLinus Torvalds if (pte_none(*src_pte)) { 4561da177e4SLinus Torvalds progress++; 4571da177e4SLinus Torvalds continue; 4581da177e4SLinus Torvalds } 4598c103762SHugh Dickins copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); 4601da177e4SLinus Torvalds progress += 8; 4611da177e4SLinus Torvalds } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 4621da177e4SLinus Torvalds 463c74df32cSHugh Dickins spin_unlock(src_ptl); 4641da177e4SLinus Torvalds pte_unmap_nested(src_pte - 1); 465ae859762SHugh Dickins add_mm_rss(dst_mm, rss[0], rss[1]); 466c74df32cSHugh Dickins pte_unmap_unlock(dst_pte - 1, dst_ptl); 467c74df32cSHugh Dickins cond_resched(); 4681da177e4SLinus Torvalds if (addr != end) 4691da177e4SLinus Torvalds goto again; 4701da177e4SLinus Torvalds return 0; 4711da177e4SLinus Torvalds } 4721da177e4SLinus Torvalds 4731da177e4SLinus Torvalds static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 4741da177e4SLinus Torvalds pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 4751da177e4SLinus Torvalds unsigned long addr, unsigned long end) 4761da177e4SLinus Torvalds { 4771da177e4SLinus Torvalds pmd_t *src_pmd, *dst_pmd; 4781da177e4SLinus Torvalds unsigned long next; 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 4811da177e4SLinus Torvalds if (!dst_pmd) 4821da177e4SLinus Torvalds return -ENOMEM; 4831da177e4SLinus Torvalds src_pmd = pmd_offset(src_pud, addr); 4841da177e4SLinus Torvalds do { 4851da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 4861da177e4SLinus Torvalds if (pmd_none_or_clear_bad(src_pmd)) 4871da177e4SLinus Torvalds continue; 4881da177e4SLinus Torvalds if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 4891da177e4SLinus Torvalds vma, addr, next)) 4901da177e4SLinus Torvalds return -ENOMEM; 4911da177e4SLinus Torvalds } while (dst_pmd++, src_pmd++, addr = next, addr != end); 4921da177e4SLinus Torvalds return 0; 4931da177e4SLinus Torvalds } 4941da177e4SLinus Torvalds 4951da177e4SLinus Torvalds static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 4961da177e4SLinus Torvalds pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 4971da177e4SLinus Torvalds unsigned long addr, unsigned long end) 4981da177e4SLinus Torvalds { 4991da177e4SLinus Torvalds pud_t *src_pud, *dst_pud; 5001da177e4SLinus Torvalds unsigned long next; 5011da177e4SLinus Torvalds 5021da177e4SLinus Torvalds dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 5031da177e4SLinus Torvalds if (!dst_pud) 5041da177e4SLinus Torvalds return -ENOMEM; 5051da177e4SLinus Torvalds src_pud = pud_offset(src_pgd, addr); 5061da177e4SLinus Torvalds do { 5071da177e4SLinus Torvalds next = pud_addr_end(addr, end); 5081da177e4SLinus Torvalds if (pud_none_or_clear_bad(src_pud)) 5091da177e4SLinus Torvalds continue; 5101da177e4SLinus Torvalds if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 5111da177e4SLinus Torvalds vma, addr, next)) 5121da177e4SLinus Torvalds return -ENOMEM; 5131da177e4SLinus Torvalds } while (dst_pud++, src_pud++, addr = next, addr != end); 5141da177e4SLinus Torvalds return 0; 5151da177e4SLinus Torvalds } 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 5181da177e4SLinus Torvalds struct vm_area_struct *vma) 5191da177e4SLinus Torvalds { 5201da177e4SLinus Torvalds pgd_t *src_pgd, *dst_pgd; 5211da177e4SLinus Torvalds unsigned long next; 5221da177e4SLinus Torvalds unsigned long addr = vma->vm_start; 5231da177e4SLinus Torvalds unsigned long end = vma->vm_end; 5241da177e4SLinus Torvalds 525d992895bSNick Piggin /* 526d992895bSNick Piggin * Don't copy ptes where a page fault will fill them correctly. 527d992895bSNick Piggin * Fork becomes much lighter when there are big shared or private 528d992895bSNick Piggin * readonly mappings. The tradeoff is that copy_page_range is more 529d992895bSNick Piggin * efficient than faulting. 530d992895bSNick Piggin */ 531d992895bSNick Piggin if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) { 532d992895bSNick Piggin if (!vma->anon_vma) 533d992895bSNick Piggin return 0; 534d992895bSNick Piggin } 535d992895bSNick Piggin 5361da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) 5371da177e4SLinus Torvalds return copy_hugetlb_page_range(dst_mm, src_mm, vma); 5381da177e4SLinus Torvalds 5391da177e4SLinus Torvalds dst_pgd = pgd_offset(dst_mm, addr); 5401da177e4SLinus Torvalds src_pgd = pgd_offset(src_mm, addr); 5411da177e4SLinus Torvalds do { 5421da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 5431da177e4SLinus Torvalds if (pgd_none_or_clear_bad(src_pgd)) 5441da177e4SLinus Torvalds continue; 5451da177e4SLinus Torvalds if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 5461da177e4SLinus Torvalds vma, addr, next)) 5471da177e4SLinus Torvalds return -ENOMEM; 5481da177e4SLinus Torvalds } while (dst_pgd++, src_pgd++, addr = next, addr != end); 5491da177e4SLinus Torvalds return 0; 5501da177e4SLinus Torvalds } 5511da177e4SLinus Torvalds 552b5810039SNick Piggin static void zap_pte_range(struct mmu_gather *tlb, 553b5810039SNick Piggin struct vm_area_struct *vma, pmd_t *pmd, 5541da177e4SLinus Torvalds unsigned long addr, unsigned long end, 5551da177e4SLinus Torvalds struct zap_details *details) 5561da177e4SLinus Torvalds { 557b5810039SNick Piggin struct mm_struct *mm = tlb->mm; 5581da177e4SLinus Torvalds pte_t *pte; 559508034a3SHugh Dickins spinlock_t *ptl; 560ae859762SHugh Dickins int file_rss = 0; 561ae859762SHugh Dickins int anon_rss = 0; 5621da177e4SLinus Torvalds 563508034a3SHugh Dickins pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 5641da177e4SLinus Torvalds do { 5651da177e4SLinus Torvalds pte_t ptent = *pte; 5661da177e4SLinus Torvalds if (pte_none(ptent)) 5671da177e4SLinus Torvalds continue; 5681da177e4SLinus Torvalds if (pte_present(ptent)) { 5691da177e4SLinus Torvalds struct page *page = NULL; 570b5810039SNick Piggin if (!(vma->vm_flags & VM_RESERVED)) { 5711da177e4SLinus Torvalds unsigned long pfn = pte_pfn(ptent); 572b5810039SNick Piggin if (unlikely(!pfn_valid(pfn))) 573b5810039SNick Piggin print_bad_pte(vma, ptent, addr); 574b5810039SNick Piggin else 5751da177e4SLinus Torvalds page = pfn_to_page(pfn); 5761da177e4SLinus Torvalds } 5771da177e4SLinus Torvalds if (unlikely(details) && page) { 5781da177e4SLinus Torvalds /* 5791da177e4SLinus Torvalds * unmap_shared_mapping_pages() wants to 5801da177e4SLinus Torvalds * invalidate cache without truncating: 5811da177e4SLinus Torvalds * unmap shared but keep private pages. 5821da177e4SLinus Torvalds */ 5831da177e4SLinus Torvalds if (details->check_mapping && 5841da177e4SLinus Torvalds details->check_mapping != page->mapping) 5851da177e4SLinus Torvalds continue; 5861da177e4SLinus Torvalds /* 5871da177e4SLinus Torvalds * Each page->index must be checked when 5881da177e4SLinus Torvalds * invalidating or truncating nonlinear. 5891da177e4SLinus Torvalds */ 5901da177e4SLinus Torvalds if (details->nonlinear_vma && 5911da177e4SLinus Torvalds (page->index < details->first_index || 5921da177e4SLinus Torvalds page->index > details->last_index)) 5931da177e4SLinus Torvalds continue; 5941da177e4SLinus Torvalds } 595b5810039SNick Piggin ptent = ptep_get_and_clear_full(mm, addr, pte, 596a600388dSZachary Amsden tlb->fullmm); 5971da177e4SLinus Torvalds tlb_remove_tlb_entry(tlb, pte, addr); 5981da177e4SLinus Torvalds if (unlikely(!page)) 5991da177e4SLinus Torvalds continue; 6001da177e4SLinus Torvalds if (unlikely(details) && details->nonlinear_vma 6011da177e4SLinus Torvalds && linear_page_index(details->nonlinear_vma, 6021da177e4SLinus Torvalds addr) != page->index) 603b5810039SNick Piggin set_pte_at(mm, addr, pte, 6041da177e4SLinus Torvalds pgoff_to_pte(page->index)); 6051da177e4SLinus Torvalds if (PageAnon(page)) 60686d912f4SHugh Dickins anon_rss--; 6076237bcd9SHugh Dickins else { 6086237bcd9SHugh Dickins if (pte_dirty(ptent)) 6096237bcd9SHugh Dickins set_page_dirty(page); 6106237bcd9SHugh Dickins if (pte_young(ptent)) 6111da177e4SLinus Torvalds mark_page_accessed(page); 61286d912f4SHugh Dickins file_rss--; 6136237bcd9SHugh Dickins } 6141da177e4SLinus Torvalds page_remove_rmap(page); 6151da177e4SLinus Torvalds tlb_remove_page(tlb, page); 6161da177e4SLinus Torvalds continue; 6171da177e4SLinus Torvalds } 6181da177e4SLinus Torvalds /* 6191da177e4SLinus Torvalds * If details->check_mapping, we leave swap entries; 6201da177e4SLinus Torvalds * if details->nonlinear_vma, we leave file entries. 6211da177e4SLinus Torvalds */ 6221da177e4SLinus Torvalds if (unlikely(details)) 6231da177e4SLinus Torvalds continue; 6241da177e4SLinus Torvalds if (!pte_file(ptent)) 6251da177e4SLinus Torvalds free_swap_and_cache(pte_to_swp_entry(ptent)); 626b5810039SNick Piggin pte_clear_full(mm, addr, pte, tlb->fullmm); 6271da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 628ae859762SHugh Dickins 62986d912f4SHugh Dickins add_mm_rss(mm, file_rss, anon_rss); 630508034a3SHugh Dickins pte_unmap_unlock(pte - 1, ptl); 6311da177e4SLinus Torvalds } 6321da177e4SLinus Torvalds 633b5810039SNick Piggin static inline void zap_pmd_range(struct mmu_gather *tlb, 634b5810039SNick Piggin struct vm_area_struct *vma, pud_t *pud, 6351da177e4SLinus Torvalds unsigned long addr, unsigned long end, 6361da177e4SLinus Torvalds struct zap_details *details) 6371da177e4SLinus Torvalds { 6381da177e4SLinus Torvalds pmd_t *pmd; 6391da177e4SLinus Torvalds unsigned long next; 6401da177e4SLinus Torvalds 6411da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 6421da177e4SLinus Torvalds do { 6431da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 6441da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 6451da177e4SLinus Torvalds continue; 646b5810039SNick Piggin zap_pte_range(tlb, vma, pmd, addr, next, details); 6471da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 6481da177e4SLinus Torvalds } 6491da177e4SLinus Torvalds 650b5810039SNick Piggin static inline void zap_pud_range(struct mmu_gather *tlb, 651b5810039SNick Piggin struct vm_area_struct *vma, pgd_t *pgd, 6521da177e4SLinus Torvalds unsigned long addr, unsigned long end, 6531da177e4SLinus Torvalds struct zap_details *details) 6541da177e4SLinus Torvalds { 6551da177e4SLinus Torvalds pud_t *pud; 6561da177e4SLinus Torvalds unsigned long next; 6571da177e4SLinus Torvalds 6581da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 6591da177e4SLinus Torvalds do { 6601da177e4SLinus Torvalds next = pud_addr_end(addr, end); 6611da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 6621da177e4SLinus Torvalds continue; 663b5810039SNick Piggin zap_pmd_range(tlb, vma, pud, addr, next, details); 6641da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 6651da177e4SLinus Torvalds } 6661da177e4SLinus Torvalds 6671da177e4SLinus Torvalds static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 6681da177e4SLinus Torvalds unsigned long addr, unsigned long end, 6691da177e4SLinus Torvalds struct zap_details *details) 6701da177e4SLinus Torvalds { 6711da177e4SLinus Torvalds pgd_t *pgd; 6721da177e4SLinus Torvalds unsigned long next; 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds if (details && !details->check_mapping && !details->nonlinear_vma) 6751da177e4SLinus Torvalds details = NULL; 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds BUG_ON(addr >= end); 6781da177e4SLinus Torvalds tlb_start_vma(tlb, vma); 6791da177e4SLinus Torvalds pgd = pgd_offset(vma->vm_mm, addr); 6801da177e4SLinus Torvalds do { 6811da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 6821da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 6831da177e4SLinus Torvalds continue; 684b5810039SNick Piggin zap_pud_range(tlb, vma, pgd, addr, next, details); 6851da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 6861da177e4SLinus Torvalds tlb_end_vma(tlb, vma); 6871da177e4SLinus Torvalds } 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds #ifdef CONFIG_PREEMPT 6901da177e4SLinus Torvalds # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) 6911da177e4SLinus Torvalds #else 6921da177e4SLinus Torvalds /* No preempt: go for improved straight-line efficiency */ 6931da177e4SLinus Torvalds # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) 6941da177e4SLinus Torvalds #endif 6951da177e4SLinus Torvalds 6961da177e4SLinus Torvalds /** 6971da177e4SLinus Torvalds * unmap_vmas - unmap a range of memory covered by a list of vma's 6981da177e4SLinus Torvalds * @tlbp: address of the caller's struct mmu_gather 6991da177e4SLinus Torvalds * @vma: the starting vma 7001da177e4SLinus Torvalds * @start_addr: virtual address at which to start unmapping 7011da177e4SLinus Torvalds * @end_addr: virtual address at which to end unmapping 7021da177e4SLinus Torvalds * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here 7031da177e4SLinus Torvalds * @details: details of nonlinear truncation or shared cache invalidation 7041da177e4SLinus Torvalds * 705ee39b37bSHugh Dickins * Returns the end address of the unmapping (restart addr if interrupted). 7061da177e4SLinus Torvalds * 707508034a3SHugh Dickins * Unmap all pages in the vma list. 7081da177e4SLinus Torvalds * 709508034a3SHugh Dickins * We aim to not hold locks for too long (for scheduling latency reasons). 710508034a3SHugh Dickins * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to 7111da177e4SLinus Torvalds * return the ending mmu_gather to the caller. 7121da177e4SLinus Torvalds * 7131da177e4SLinus Torvalds * Only addresses between `start' and `end' will be unmapped. 7141da177e4SLinus Torvalds * 7151da177e4SLinus Torvalds * The VMA list must be sorted in ascending virtual address order. 7161da177e4SLinus Torvalds * 7171da177e4SLinus Torvalds * unmap_vmas() assumes that the caller will flush the whole unmapped address 7181da177e4SLinus Torvalds * range after unmap_vmas() returns. So the only responsibility here is to 7191da177e4SLinus Torvalds * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 7201da177e4SLinus Torvalds * drops the lock and schedules. 7211da177e4SLinus Torvalds */ 722508034a3SHugh Dickins unsigned long unmap_vmas(struct mmu_gather **tlbp, 7231da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long start_addr, 7241da177e4SLinus Torvalds unsigned long end_addr, unsigned long *nr_accounted, 7251da177e4SLinus Torvalds struct zap_details *details) 7261da177e4SLinus Torvalds { 7271da177e4SLinus Torvalds unsigned long zap_bytes = ZAP_BLOCK_SIZE; 7281da177e4SLinus Torvalds unsigned long tlb_start = 0; /* For tlb_finish_mmu */ 7291da177e4SLinus Torvalds int tlb_start_valid = 0; 730ee39b37bSHugh Dickins unsigned long start = start_addr; 7311da177e4SLinus Torvalds spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; 7324d6ddfa9SHugh Dickins int fullmm = (*tlbp)->fullmm; 7331da177e4SLinus Torvalds 7341da177e4SLinus Torvalds for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { 7351da177e4SLinus Torvalds unsigned long end; 7361da177e4SLinus Torvalds 7371da177e4SLinus Torvalds start = max(vma->vm_start, start_addr); 7381da177e4SLinus Torvalds if (start >= vma->vm_end) 7391da177e4SLinus Torvalds continue; 7401da177e4SLinus Torvalds end = min(vma->vm_end, end_addr); 7411da177e4SLinus Torvalds if (end <= vma->vm_start) 7421da177e4SLinus Torvalds continue; 7431da177e4SLinus Torvalds 7441da177e4SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 7451da177e4SLinus Torvalds *nr_accounted += (end - start) >> PAGE_SHIFT; 7461da177e4SLinus Torvalds 7471da177e4SLinus Torvalds while (start != end) { 7481da177e4SLinus Torvalds unsigned long block; 7491da177e4SLinus Torvalds 7501da177e4SLinus Torvalds if (!tlb_start_valid) { 7511da177e4SLinus Torvalds tlb_start = start; 7521da177e4SLinus Torvalds tlb_start_valid = 1; 7531da177e4SLinus Torvalds } 7541da177e4SLinus Torvalds 7551da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) { 7561da177e4SLinus Torvalds block = end - start; 7571da177e4SLinus Torvalds unmap_hugepage_range(vma, start, end); 7581da177e4SLinus Torvalds } else { 7591da177e4SLinus Torvalds block = min(zap_bytes, end - start); 7601da177e4SLinus Torvalds unmap_page_range(*tlbp, vma, start, 7611da177e4SLinus Torvalds start + block, details); 7621da177e4SLinus Torvalds } 7631da177e4SLinus Torvalds 7641da177e4SLinus Torvalds start += block; 7651da177e4SLinus Torvalds zap_bytes -= block; 7661da177e4SLinus Torvalds if ((long)zap_bytes > 0) 7671da177e4SLinus Torvalds continue; 7681da177e4SLinus Torvalds 7691da177e4SLinus Torvalds tlb_finish_mmu(*tlbp, tlb_start, start); 7701da177e4SLinus Torvalds 7711da177e4SLinus Torvalds if (need_resched() || 7721da177e4SLinus Torvalds (i_mmap_lock && need_lockbreak(i_mmap_lock))) { 7731da177e4SLinus Torvalds if (i_mmap_lock) { 774508034a3SHugh Dickins *tlbp = NULL; 7751da177e4SLinus Torvalds goto out; 7761da177e4SLinus Torvalds } 7771da177e4SLinus Torvalds cond_resched(); 7781da177e4SLinus Torvalds } 7791da177e4SLinus Torvalds 780508034a3SHugh Dickins *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); 7811da177e4SLinus Torvalds tlb_start_valid = 0; 7821da177e4SLinus Torvalds zap_bytes = ZAP_BLOCK_SIZE; 7831da177e4SLinus Torvalds } 7841da177e4SLinus Torvalds } 7851da177e4SLinus Torvalds out: 786ee39b37bSHugh Dickins return start; /* which is now the end (or restart) address */ 7871da177e4SLinus Torvalds } 7881da177e4SLinus Torvalds 7891da177e4SLinus Torvalds /** 7901da177e4SLinus Torvalds * zap_page_range - remove user pages in a given range 7911da177e4SLinus Torvalds * @vma: vm_area_struct holding the applicable pages 7921da177e4SLinus Torvalds * @address: starting address of pages to zap 7931da177e4SLinus Torvalds * @size: number of bytes to zap 7941da177e4SLinus Torvalds * @details: details of nonlinear truncation or shared cache invalidation 7951da177e4SLinus Torvalds */ 796ee39b37bSHugh Dickins unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 7971da177e4SLinus Torvalds unsigned long size, struct zap_details *details) 7981da177e4SLinus Torvalds { 7991da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 8001da177e4SLinus Torvalds struct mmu_gather *tlb; 8011da177e4SLinus Torvalds unsigned long end = address + size; 8021da177e4SLinus Torvalds unsigned long nr_accounted = 0; 8031da177e4SLinus Torvalds 8041da177e4SLinus Torvalds lru_add_drain(); 8051da177e4SLinus Torvalds tlb = tlb_gather_mmu(mm, 0); 806365e9c87SHugh Dickins update_hiwater_rss(mm); 807508034a3SHugh Dickins end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); 808508034a3SHugh Dickins if (tlb) 8098f4f8c16SHugh Dickins tlb_finish_mmu(tlb, address, end); 810ee39b37bSHugh Dickins return end; 8111da177e4SLinus Torvalds } 8121da177e4SLinus Torvalds 8131da177e4SLinus Torvalds /* 8141da177e4SLinus Torvalds * Do a quick page-table lookup for a single page. 8151da177e4SLinus Torvalds */ 816deceb6cdSHugh Dickins struct page *follow_page(struct mm_struct *mm, unsigned long address, 817deceb6cdSHugh Dickins unsigned int flags) 8181da177e4SLinus Torvalds { 8191da177e4SLinus Torvalds pgd_t *pgd; 8201da177e4SLinus Torvalds pud_t *pud; 8211da177e4SLinus Torvalds pmd_t *pmd; 8221da177e4SLinus Torvalds pte_t *ptep, pte; 823deceb6cdSHugh Dickins spinlock_t *ptl; 8241da177e4SLinus Torvalds unsigned long pfn; 8251da177e4SLinus Torvalds struct page *page; 8261da177e4SLinus Torvalds 827deceb6cdSHugh Dickins page = follow_huge_addr(mm, address, flags & FOLL_WRITE); 828deceb6cdSHugh Dickins if (!IS_ERR(page)) { 829deceb6cdSHugh Dickins BUG_ON(flags & FOLL_GET); 830deceb6cdSHugh Dickins goto out; 831deceb6cdSHugh Dickins } 8321da177e4SLinus Torvalds 833deceb6cdSHugh Dickins page = NULL; 8341da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 8351da177e4SLinus Torvalds if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 836deceb6cdSHugh Dickins goto no_page_table; 8371da177e4SLinus Torvalds 8381da177e4SLinus Torvalds pud = pud_offset(pgd, address); 8391da177e4SLinus Torvalds if (pud_none(*pud) || unlikely(pud_bad(*pud))) 840deceb6cdSHugh Dickins goto no_page_table; 8411da177e4SLinus Torvalds 8421da177e4SLinus Torvalds pmd = pmd_offset(pud, address); 8431da177e4SLinus Torvalds if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 844deceb6cdSHugh Dickins goto no_page_table; 8451da177e4SLinus Torvalds 846deceb6cdSHugh Dickins if (pmd_huge(*pmd)) { 847deceb6cdSHugh Dickins BUG_ON(flags & FOLL_GET); 848deceb6cdSHugh Dickins page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); 849deceb6cdSHugh Dickins goto out; 850deceb6cdSHugh Dickins } 851deceb6cdSHugh Dickins 852deceb6cdSHugh Dickins ptep = pte_offset_map_lock(mm, pmd, address, &ptl); 8531da177e4SLinus Torvalds if (!ptep) 8541da177e4SLinus Torvalds goto out; 8551da177e4SLinus Torvalds 8561da177e4SLinus Torvalds pte = *ptep; 857deceb6cdSHugh Dickins if (!pte_present(pte)) 858deceb6cdSHugh Dickins goto unlock; 859deceb6cdSHugh Dickins if ((flags & FOLL_WRITE) && !pte_write(pte)) 860deceb6cdSHugh Dickins goto unlock; 8611da177e4SLinus Torvalds pfn = pte_pfn(pte); 862deceb6cdSHugh Dickins if (!pfn_valid(pfn)) 863deceb6cdSHugh Dickins goto unlock; 864deceb6cdSHugh Dickins 8651da177e4SLinus Torvalds page = pfn_to_page(pfn); 866deceb6cdSHugh Dickins if (flags & FOLL_GET) 867deceb6cdSHugh Dickins get_page(page); 868deceb6cdSHugh Dickins if (flags & FOLL_TOUCH) { 869deceb6cdSHugh Dickins if ((flags & FOLL_WRITE) && 870deceb6cdSHugh Dickins !pte_dirty(pte) && !PageDirty(page)) 871f33ea7f4SNick Piggin set_page_dirty(page); 8721da177e4SLinus Torvalds mark_page_accessed(page); 8731da177e4SLinus Torvalds } 874deceb6cdSHugh Dickins unlock: 875deceb6cdSHugh Dickins pte_unmap_unlock(ptep, ptl); 8761da177e4SLinus Torvalds out: 877deceb6cdSHugh Dickins return page; 878deceb6cdSHugh Dickins 879deceb6cdSHugh Dickins no_page_table: 880deceb6cdSHugh Dickins /* 881deceb6cdSHugh Dickins * When core dumping an enormous anonymous area that nobody 882deceb6cdSHugh Dickins * has touched so far, we don't want to allocate page tables. 883deceb6cdSHugh Dickins */ 884deceb6cdSHugh Dickins if (flags & FOLL_ANON) { 885deceb6cdSHugh Dickins page = ZERO_PAGE(address); 886deceb6cdSHugh Dickins if (flags & FOLL_GET) 887deceb6cdSHugh Dickins get_page(page); 888deceb6cdSHugh Dickins BUG_ON(flags & FOLL_WRITE); 8891da177e4SLinus Torvalds } 890deceb6cdSHugh Dickins return page; 8911da177e4SLinus Torvalds } 8921da177e4SLinus Torvalds 8931da177e4SLinus Torvalds int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 8941da177e4SLinus Torvalds unsigned long start, int len, int write, int force, 8951da177e4SLinus Torvalds struct page **pages, struct vm_area_struct **vmas) 8961da177e4SLinus Torvalds { 8971da177e4SLinus Torvalds int i; 898deceb6cdSHugh Dickins unsigned int vm_flags; 8991da177e4SLinus Torvalds 9001da177e4SLinus Torvalds /* 9011da177e4SLinus Torvalds * Require read or write permissions. 9021da177e4SLinus Torvalds * If 'force' is set, we only require the "MAY" flags. 9031da177e4SLinus Torvalds */ 904deceb6cdSHugh Dickins vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 905deceb6cdSHugh Dickins vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 9061da177e4SLinus Torvalds i = 0; 9071da177e4SLinus Torvalds 9081da177e4SLinus Torvalds do { 9091da177e4SLinus Torvalds struct vm_area_struct *vma; 910deceb6cdSHugh Dickins unsigned int foll_flags; 9111da177e4SLinus Torvalds 9121da177e4SLinus Torvalds vma = find_extend_vma(mm, start); 9131da177e4SLinus Torvalds if (!vma && in_gate_area(tsk, start)) { 9141da177e4SLinus Torvalds unsigned long pg = start & PAGE_MASK; 9151da177e4SLinus Torvalds struct vm_area_struct *gate_vma = get_gate_vma(tsk); 9161da177e4SLinus Torvalds pgd_t *pgd; 9171da177e4SLinus Torvalds pud_t *pud; 9181da177e4SLinus Torvalds pmd_t *pmd; 9191da177e4SLinus Torvalds pte_t *pte; 9201da177e4SLinus Torvalds if (write) /* user gate pages are read-only */ 9211da177e4SLinus Torvalds return i ? : -EFAULT; 9221da177e4SLinus Torvalds if (pg > TASK_SIZE) 9231da177e4SLinus Torvalds pgd = pgd_offset_k(pg); 9241da177e4SLinus Torvalds else 9251da177e4SLinus Torvalds pgd = pgd_offset_gate(mm, pg); 9261da177e4SLinus Torvalds BUG_ON(pgd_none(*pgd)); 9271da177e4SLinus Torvalds pud = pud_offset(pgd, pg); 9281da177e4SLinus Torvalds BUG_ON(pud_none(*pud)); 9291da177e4SLinus Torvalds pmd = pmd_offset(pud, pg); 930690dbe1cSHugh Dickins if (pmd_none(*pmd)) 931690dbe1cSHugh Dickins return i ? : -EFAULT; 9321da177e4SLinus Torvalds pte = pte_offset_map(pmd, pg); 933690dbe1cSHugh Dickins if (pte_none(*pte)) { 934690dbe1cSHugh Dickins pte_unmap(pte); 935690dbe1cSHugh Dickins return i ? : -EFAULT; 936690dbe1cSHugh Dickins } 9371da177e4SLinus Torvalds if (pages) { 9381da177e4SLinus Torvalds pages[i] = pte_page(*pte); 9391da177e4SLinus Torvalds get_page(pages[i]); 9401da177e4SLinus Torvalds } 9411da177e4SLinus Torvalds pte_unmap(pte); 9421da177e4SLinus Torvalds if (vmas) 9431da177e4SLinus Torvalds vmas[i] = gate_vma; 9441da177e4SLinus Torvalds i++; 9451da177e4SLinus Torvalds start += PAGE_SIZE; 9461da177e4SLinus Torvalds len--; 9471da177e4SLinus Torvalds continue; 9481da177e4SLinus Torvalds } 9491da177e4SLinus Torvalds 950b5810039SNick Piggin if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED)) 951deceb6cdSHugh Dickins || !(vm_flags & vma->vm_flags)) 9521da177e4SLinus Torvalds return i ? : -EFAULT; 9531da177e4SLinus Torvalds 9541da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) { 9551da177e4SLinus Torvalds i = follow_hugetlb_page(mm, vma, pages, vmas, 9561da177e4SLinus Torvalds &start, &len, i); 9571da177e4SLinus Torvalds continue; 9581da177e4SLinus Torvalds } 959deceb6cdSHugh Dickins 960deceb6cdSHugh Dickins foll_flags = FOLL_TOUCH; 961deceb6cdSHugh Dickins if (pages) 962deceb6cdSHugh Dickins foll_flags |= FOLL_GET; 963deceb6cdSHugh Dickins if (!write && !(vma->vm_flags & VM_LOCKED) && 964deceb6cdSHugh Dickins (!vma->vm_ops || !vma->vm_ops->nopage)) 965deceb6cdSHugh Dickins foll_flags |= FOLL_ANON; 966deceb6cdSHugh Dickins 9671da177e4SLinus Torvalds do { 96808ef4729SHugh Dickins struct page *page; 9691da177e4SLinus Torvalds 970deceb6cdSHugh Dickins if (write) 971deceb6cdSHugh Dickins foll_flags |= FOLL_WRITE; 972deceb6cdSHugh Dickins 973deceb6cdSHugh Dickins cond_resched(); 974deceb6cdSHugh Dickins while (!(page = follow_page(mm, start, foll_flags))) { 975a68d2ebcSLinus Torvalds int ret; 976deceb6cdSHugh Dickins ret = __handle_mm_fault(mm, vma, start, 977deceb6cdSHugh Dickins foll_flags & FOLL_WRITE); 978f33ea7f4SNick Piggin /* 979a68d2ebcSLinus Torvalds * The VM_FAULT_WRITE bit tells us that do_wp_page has 980a68d2ebcSLinus Torvalds * broken COW when necessary, even if maybe_mkwrite 981a68d2ebcSLinus Torvalds * decided not to set pte_write. We can thus safely do 982a68d2ebcSLinus Torvalds * subsequent page lookups as if they were reads. 983f33ea7f4SNick Piggin */ 984a68d2ebcSLinus Torvalds if (ret & VM_FAULT_WRITE) 985deceb6cdSHugh Dickins foll_flags &= ~FOLL_WRITE; 986a68d2ebcSLinus Torvalds 987a68d2ebcSLinus Torvalds switch (ret & ~VM_FAULT_WRITE) { 9881da177e4SLinus Torvalds case VM_FAULT_MINOR: 9891da177e4SLinus Torvalds tsk->min_flt++; 9901da177e4SLinus Torvalds break; 9911da177e4SLinus Torvalds case VM_FAULT_MAJOR: 9921da177e4SLinus Torvalds tsk->maj_flt++; 9931da177e4SLinus Torvalds break; 9941da177e4SLinus Torvalds case VM_FAULT_SIGBUS: 9951da177e4SLinus Torvalds return i ? i : -EFAULT; 9961da177e4SLinus Torvalds case VM_FAULT_OOM: 9971da177e4SLinus Torvalds return i ? i : -ENOMEM; 9981da177e4SLinus Torvalds default: 9991da177e4SLinus Torvalds BUG(); 10001da177e4SLinus Torvalds } 10011da177e4SLinus Torvalds } 10021da177e4SLinus Torvalds if (pages) { 100308ef4729SHugh Dickins pages[i] = page; 100408ef4729SHugh Dickins flush_dcache_page(page); 10051da177e4SLinus Torvalds } 10061da177e4SLinus Torvalds if (vmas) 10071da177e4SLinus Torvalds vmas[i] = vma; 10081da177e4SLinus Torvalds i++; 10091da177e4SLinus Torvalds start += PAGE_SIZE; 10101da177e4SLinus Torvalds len--; 10111da177e4SLinus Torvalds } while (len && start < vma->vm_end); 10121da177e4SLinus Torvalds } while (len); 10131da177e4SLinus Torvalds return i; 10141da177e4SLinus Torvalds } 10151da177e4SLinus Torvalds EXPORT_SYMBOL(get_user_pages); 10161da177e4SLinus Torvalds 10171da177e4SLinus Torvalds static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, 10181da177e4SLinus Torvalds unsigned long addr, unsigned long end, pgprot_t prot) 10191da177e4SLinus Torvalds { 10201da177e4SLinus Torvalds pte_t *pte; 1021c74df32cSHugh Dickins spinlock_t *ptl; 10221da177e4SLinus Torvalds 1023c74df32cSHugh Dickins pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 10241da177e4SLinus Torvalds if (!pte) 10251da177e4SLinus Torvalds return -ENOMEM; 10261da177e4SLinus Torvalds do { 1027b5810039SNick Piggin struct page *page = ZERO_PAGE(addr); 1028b5810039SNick Piggin pte_t zero_pte = pte_wrprotect(mk_pte(page, prot)); 1029b5810039SNick Piggin page_cache_get(page); 1030b5810039SNick Piggin page_add_file_rmap(page); 1031b5810039SNick Piggin inc_mm_counter(mm, file_rss); 10321da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 10331da177e4SLinus Torvalds set_pte_at(mm, addr, pte, zero_pte); 10341da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 1035c74df32cSHugh Dickins pte_unmap_unlock(pte - 1, ptl); 10361da177e4SLinus Torvalds return 0; 10371da177e4SLinus Torvalds } 10381da177e4SLinus Torvalds 10391da177e4SLinus Torvalds static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, 10401da177e4SLinus Torvalds unsigned long addr, unsigned long end, pgprot_t prot) 10411da177e4SLinus Torvalds { 10421da177e4SLinus Torvalds pmd_t *pmd; 10431da177e4SLinus Torvalds unsigned long next; 10441da177e4SLinus Torvalds 10451da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 10461da177e4SLinus Torvalds if (!pmd) 10471da177e4SLinus Torvalds return -ENOMEM; 10481da177e4SLinus Torvalds do { 10491da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 10501da177e4SLinus Torvalds if (zeromap_pte_range(mm, pmd, addr, next, prot)) 10511da177e4SLinus Torvalds return -ENOMEM; 10521da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 10531da177e4SLinus Torvalds return 0; 10541da177e4SLinus Torvalds } 10551da177e4SLinus Torvalds 10561da177e4SLinus Torvalds static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, 10571da177e4SLinus Torvalds unsigned long addr, unsigned long end, pgprot_t prot) 10581da177e4SLinus Torvalds { 10591da177e4SLinus Torvalds pud_t *pud; 10601da177e4SLinus Torvalds unsigned long next; 10611da177e4SLinus Torvalds 10621da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, addr); 10631da177e4SLinus Torvalds if (!pud) 10641da177e4SLinus Torvalds return -ENOMEM; 10651da177e4SLinus Torvalds do { 10661da177e4SLinus Torvalds next = pud_addr_end(addr, end); 10671da177e4SLinus Torvalds if (zeromap_pmd_range(mm, pud, addr, next, prot)) 10681da177e4SLinus Torvalds return -ENOMEM; 10691da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 10701da177e4SLinus Torvalds return 0; 10711da177e4SLinus Torvalds } 10721da177e4SLinus Torvalds 10731da177e4SLinus Torvalds int zeromap_page_range(struct vm_area_struct *vma, 10741da177e4SLinus Torvalds unsigned long addr, unsigned long size, pgprot_t prot) 10751da177e4SLinus Torvalds { 10761da177e4SLinus Torvalds pgd_t *pgd; 10771da177e4SLinus Torvalds unsigned long next; 10781da177e4SLinus Torvalds unsigned long end = addr + size; 10791da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 10801da177e4SLinus Torvalds int err; 10811da177e4SLinus Torvalds 10821da177e4SLinus Torvalds BUG_ON(addr >= end); 10831da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 10841da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 10851da177e4SLinus Torvalds do { 10861da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 10871da177e4SLinus Torvalds err = zeromap_pud_range(mm, pgd, addr, next, prot); 10881da177e4SLinus Torvalds if (err) 10891da177e4SLinus Torvalds break; 10901da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 10911da177e4SLinus Torvalds return err; 10921da177e4SLinus Torvalds } 10931da177e4SLinus Torvalds 10941da177e4SLinus Torvalds /* 10951da177e4SLinus Torvalds * maps a range of physical memory into the requested pages. the old 10961da177e4SLinus Torvalds * mappings are removed. any references to nonexistent pages results 10971da177e4SLinus Torvalds * in null mappings (currently treated as "copy-on-access") 10981da177e4SLinus Torvalds */ 10991da177e4SLinus Torvalds static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 11001da177e4SLinus Torvalds unsigned long addr, unsigned long end, 11011da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 11021da177e4SLinus Torvalds { 11031da177e4SLinus Torvalds pte_t *pte; 1104c74df32cSHugh Dickins spinlock_t *ptl; 11051da177e4SLinus Torvalds 1106c74df32cSHugh Dickins pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 11071da177e4SLinus Torvalds if (!pte) 11081da177e4SLinus Torvalds return -ENOMEM; 11091da177e4SLinus Torvalds do { 11101da177e4SLinus Torvalds BUG_ON(!pte_none(*pte)); 11111da177e4SLinus Torvalds set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 11121da177e4SLinus Torvalds pfn++; 11131da177e4SLinus Torvalds } while (pte++, addr += PAGE_SIZE, addr != end); 1114c74df32cSHugh Dickins pte_unmap_unlock(pte - 1, ptl); 11151da177e4SLinus Torvalds return 0; 11161da177e4SLinus Torvalds } 11171da177e4SLinus Torvalds 11181da177e4SLinus Torvalds static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 11191da177e4SLinus Torvalds unsigned long addr, unsigned long end, 11201da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 11211da177e4SLinus Torvalds { 11221da177e4SLinus Torvalds pmd_t *pmd; 11231da177e4SLinus Torvalds unsigned long next; 11241da177e4SLinus Torvalds 11251da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 11261da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 11271da177e4SLinus Torvalds if (!pmd) 11281da177e4SLinus Torvalds return -ENOMEM; 11291da177e4SLinus Torvalds do { 11301da177e4SLinus Torvalds next = pmd_addr_end(addr, end); 11311da177e4SLinus Torvalds if (remap_pte_range(mm, pmd, addr, next, 11321da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 11331da177e4SLinus Torvalds return -ENOMEM; 11341da177e4SLinus Torvalds } while (pmd++, addr = next, addr != end); 11351da177e4SLinus Torvalds return 0; 11361da177e4SLinus Torvalds } 11371da177e4SLinus Torvalds 11381da177e4SLinus Torvalds static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 11391da177e4SLinus Torvalds unsigned long addr, unsigned long end, 11401da177e4SLinus Torvalds unsigned long pfn, pgprot_t prot) 11411da177e4SLinus Torvalds { 11421da177e4SLinus Torvalds pud_t *pud; 11431da177e4SLinus Torvalds unsigned long next; 11441da177e4SLinus Torvalds 11451da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 11461da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, addr); 11471da177e4SLinus Torvalds if (!pud) 11481da177e4SLinus Torvalds return -ENOMEM; 11491da177e4SLinus Torvalds do { 11501da177e4SLinus Torvalds next = pud_addr_end(addr, end); 11511da177e4SLinus Torvalds if (remap_pmd_range(mm, pud, addr, next, 11521da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot)) 11531da177e4SLinus Torvalds return -ENOMEM; 11541da177e4SLinus Torvalds } while (pud++, addr = next, addr != end); 11551da177e4SLinus Torvalds return 0; 11561da177e4SLinus Torvalds } 11571da177e4SLinus Torvalds 11581da177e4SLinus Torvalds /* Note: this is only safe if the mm semaphore is held when called. */ 11591da177e4SLinus Torvalds int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 11601da177e4SLinus Torvalds unsigned long pfn, unsigned long size, pgprot_t prot) 11611da177e4SLinus Torvalds { 11621da177e4SLinus Torvalds pgd_t *pgd; 11631da177e4SLinus Torvalds unsigned long next; 11642d15cab8SHugh Dickins unsigned long end = addr + PAGE_ALIGN(size); 11651da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 11661da177e4SLinus Torvalds int err; 11671da177e4SLinus Torvalds 11681da177e4SLinus Torvalds /* 11691da177e4SLinus Torvalds * Physically remapped pages are special. Tell the 11701da177e4SLinus Torvalds * rest of the world about it: 11711da177e4SLinus Torvalds * VM_IO tells people not to look at these pages 11721da177e4SLinus Torvalds * (accesses can have side effects). 1173b5810039SNick Piggin * VM_RESERVED tells the core MM not to "manage" these pages 1174b5810039SNick Piggin * (e.g. refcount, mapcount, try to swap them out). 11751da177e4SLinus Torvalds */ 11761da177e4SLinus Torvalds vma->vm_flags |= VM_IO | VM_RESERVED; 11771da177e4SLinus Torvalds 11781da177e4SLinus Torvalds BUG_ON(addr >= end); 11791da177e4SLinus Torvalds pfn -= addr >> PAGE_SHIFT; 11801da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 11811da177e4SLinus Torvalds flush_cache_range(vma, addr, end); 11821da177e4SLinus Torvalds do { 11831da177e4SLinus Torvalds next = pgd_addr_end(addr, end); 11841da177e4SLinus Torvalds err = remap_pud_range(mm, pgd, addr, next, 11851da177e4SLinus Torvalds pfn + (addr >> PAGE_SHIFT), prot); 11861da177e4SLinus Torvalds if (err) 11871da177e4SLinus Torvalds break; 11881da177e4SLinus Torvalds } while (pgd++, addr = next, addr != end); 11891da177e4SLinus Torvalds return err; 11901da177e4SLinus Torvalds } 11911da177e4SLinus Torvalds EXPORT_SYMBOL(remap_pfn_range); 11921da177e4SLinus Torvalds 11931da177e4SLinus Torvalds /* 11948f4e2101SHugh Dickins * handle_pte_fault chooses page fault handler according to an entry 11958f4e2101SHugh Dickins * which was read non-atomically. Before making any commitment, on 11968f4e2101SHugh Dickins * those architectures or configurations (e.g. i386 with PAE) which 11978f4e2101SHugh Dickins * might give a mix of unmatched parts, do_swap_page and do_file_page 11988f4e2101SHugh Dickins * must check under lock before unmapping the pte and proceeding 11998f4e2101SHugh Dickins * (but do_wp_page is only called after already making such a check; 12008f4e2101SHugh Dickins * and do_anonymous_page and do_no_page can safely check later on). 12018f4e2101SHugh Dickins */ 12024c21e2f2SHugh Dickins static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 12038f4e2101SHugh Dickins pte_t *page_table, pte_t orig_pte) 12048f4e2101SHugh Dickins { 12058f4e2101SHugh Dickins int same = 1; 12068f4e2101SHugh Dickins #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) 12078f4e2101SHugh Dickins if (sizeof(pte_t) > sizeof(unsigned long)) { 12084c21e2f2SHugh Dickins spinlock_t *ptl = pte_lockptr(mm, pmd); 12094c21e2f2SHugh Dickins spin_lock(ptl); 12108f4e2101SHugh Dickins same = pte_same(*page_table, orig_pte); 12114c21e2f2SHugh Dickins spin_unlock(ptl); 12128f4e2101SHugh Dickins } 12138f4e2101SHugh Dickins #endif 12148f4e2101SHugh Dickins pte_unmap(page_table); 12158f4e2101SHugh Dickins return same; 12168f4e2101SHugh Dickins } 12178f4e2101SHugh Dickins 12188f4e2101SHugh Dickins /* 12191da177e4SLinus Torvalds * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 12201da177e4SLinus Torvalds * servicing faults for write access. In the normal case, do always want 12211da177e4SLinus Torvalds * pte_mkwrite. But get_user_pages can cause write faults for mappings 12221da177e4SLinus Torvalds * that do not have writing enabled, when used by access_process_vm. 12231da177e4SLinus Torvalds */ 12241da177e4SLinus Torvalds static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 12251da177e4SLinus Torvalds { 12261da177e4SLinus Torvalds if (likely(vma->vm_flags & VM_WRITE)) 12271da177e4SLinus Torvalds pte = pte_mkwrite(pte); 12281da177e4SLinus Torvalds return pte; 12291da177e4SLinus Torvalds } 12301da177e4SLinus Torvalds 12311da177e4SLinus Torvalds /* 12321da177e4SLinus Torvalds * This routine handles present pages, when users try to write 12331da177e4SLinus Torvalds * to a shared page. It is done by copying the page to a new address 12341da177e4SLinus Torvalds * and decrementing the shared-page counter for the old page. 12351da177e4SLinus Torvalds * 12361da177e4SLinus Torvalds * Note that this routine assumes that the protection checks have been 12371da177e4SLinus Torvalds * done by the caller (the low-level page fault routine in most cases). 12381da177e4SLinus Torvalds * Thus we can safely just mark it writable once we've done any necessary 12391da177e4SLinus Torvalds * COW. 12401da177e4SLinus Torvalds * 12411da177e4SLinus Torvalds * We also mark the page dirty at this point even though the page will 12421da177e4SLinus Torvalds * change only once the write actually happens. This avoids a few races, 12431da177e4SLinus Torvalds * and potentially makes it more efficient. 12441da177e4SLinus Torvalds * 12458f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 12468f4e2101SHugh Dickins * but allow concurrent faults), with pte both mapped and locked. 12478f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 12481da177e4SLinus Torvalds */ 12491da177e4SLinus Torvalds static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 125065500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 12518f4e2101SHugh Dickins spinlock_t *ptl, pte_t orig_pte) 12521da177e4SLinus Torvalds { 12531da177e4SLinus Torvalds struct page *old_page, *new_page; 125465500d23SHugh Dickins unsigned long pfn = pte_pfn(orig_pte); 12551da177e4SLinus Torvalds pte_t entry; 125665500d23SHugh Dickins int ret = VM_FAULT_MINOR; 12571da177e4SLinus Torvalds 1258b5810039SNick Piggin BUG_ON(vma->vm_flags & VM_RESERVED); 1259b5810039SNick Piggin 12601da177e4SLinus Torvalds if (unlikely(!pfn_valid(pfn))) { 12611da177e4SLinus Torvalds /* 126265500d23SHugh Dickins * Page table corrupted: show pte and kill process. 12631da177e4SLinus Torvalds */ 1264b5810039SNick Piggin print_bad_pte(vma, orig_pte, address); 126565500d23SHugh Dickins ret = VM_FAULT_OOM; 126665500d23SHugh Dickins goto unlock; 12671da177e4SLinus Torvalds } 12681da177e4SLinus Torvalds old_page = pfn_to_page(pfn); 12691da177e4SLinus Torvalds 1270d296e9cdSHugh Dickins if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { 12711da177e4SLinus Torvalds int reuse = can_share_swap_page(old_page); 12721da177e4SLinus Torvalds unlock_page(old_page); 12731da177e4SLinus Torvalds if (reuse) { 12741da177e4SLinus Torvalds flush_cache_page(vma, address, pfn); 127565500d23SHugh Dickins entry = pte_mkyoung(orig_pte); 127665500d23SHugh Dickins entry = maybe_mkwrite(pte_mkdirty(entry), vma); 12771da177e4SLinus Torvalds ptep_set_access_flags(vma, address, page_table, entry, 1); 12781da177e4SLinus Torvalds update_mmu_cache(vma, address, entry); 12791da177e4SLinus Torvalds lazy_mmu_prot_update(entry); 128065500d23SHugh Dickins ret |= VM_FAULT_WRITE; 128165500d23SHugh Dickins goto unlock; 12821da177e4SLinus Torvalds } 12831da177e4SLinus Torvalds } 12841da177e4SLinus Torvalds 12851da177e4SLinus Torvalds /* 12861da177e4SLinus Torvalds * Ok, we need to copy. Oh, well.. 12871da177e4SLinus Torvalds */ 12881da177e4SLinus Torvalds page_cache_get(old_page); 12898f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 12901da177e4SLinus Torvalds 12911da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 129265500d23SHugh Dickins goto oom; 12931da177e4SLinus Torvalds if (old_page == ZERO_PAGE(address)) { 12941da177e4SLinus Torvalds new_page = alloc_zeroed_user_highpage(vma, address); 12951da177e4SLinus Torvalds if (!new_page) 129665500d23SHugh Dickins goto oom; 12971da177e4SLinus Torvalds } else { 12981da177e4SLinus Torvalds new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 12991da177e4SLinus Torvalds if (!new_page) 130065500d23SHugh Dickins goto oom; 13011da177e4SLinus Torvalds copy_user_highpage(new_page, old_page, address); 13021da177e4SLinus Torvalds } 130365500d23SHugh Dickins 13041da177e4SLinus Torvalds /* 13051da177e4SLinus Torvalds * Re-check the pte - we dropped the lock 13061da177e4SLinus Torvalds */ 13078f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 130865500d23SHugh Dickins if (likely(pte_same(*page_table, orig_pte))) { 13091da177e4SLinus Torvalds page_remove_rmap(old_page); 13104294621fSHugh Dickins if (!PageAnon(old_page)) { 13114294621fSHugh Dickins inc_mm_counter(mm, anon_rss); 13124294621fSHugh Dickins dec_mm_counter(mm, file_rss); 13134294621fSHugh Dickins } 13141da177e4SLinus Torvalds flush_cache_page(vma, address, pfn); 131565500d23SHugh Dickins entry = mk_pte(new_page, vma->vm_page_prot); 131665500d23SHugh Dickins entry = maybe_mkwrite(pte_mkdirty(entry), vma); 131765500d23SHugh Dickins ptep_establish(vma, address, page_table, entry); 131865500d23SHugh Dickins update_mmu_cache(vma, address, entry); 131965500d23SHugh Dickins lazy_mmu_prot_update(entry); 13201da177e4SLinus Torvalds lru_cache_add_active(new_page); 13211da177e4SLinus Torvalds page_add_anon_rmap(new_page, vma, address); 13221da177e4SLinus Torvalds 13231da177e4SLinus Torvalds /* Free the old page.. */ 13241da177e4SLinus Torvalds new_page = old_page; 1325f33ea7f4SNick Piggin ret |= VM_FAULT_WRITE; 13261da177e4SLinus Torvalds } 13271da177e4SLinus Torvalds page_cache_release(new_page); 13281da177e4SLinus Torvalds page_cache_release(old_page); 132965500d23SHugh Dickins unlock: 13308f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 1331f33ea7f4SNick Piggin return ret; 133265500d23SHugh Dickins oom: 13331da177e4SLinus Torvalds page_cache_release(old_page); 13341da177e4SLinus Torvalds return VM_FAULT_OOM; 13351da177e4SLinus Torvalds } 13361da177e4SLinus Torvalds 13371da177e4SLinus Torvalds /* 13381da177e4SLinus Torvalds * Helper functions for unmap_mapping_range(). 13391da177e4SLinus Torvalds * 13401da177e4SLinus Torvalds * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 13411da177e4SLinus Torvalds * 13421da177e4SLinus Torvalds * We have to restart searching the prio_tree whenever we drop the lock, 13431da177e4SLinus Torvalds * since the iterator is only valid while the lock is held, and anyway 13441da177e4SLinus Torvalds * a later vma might be split and reinserted earlier while lock dropped. 13451da177e4SLinus Torvalds * 13461da177e4SLinus Torvalds * The list of nonlinear vmas could be handled more efficiently, using 13471da177e4SLinus Torvalds * a placeholder, but handle it in the same way until a need is shown. 13481da177e4SLinus Torvalds * It is important to search the prio_tree before nonlinear list: a vma 13491da177e4SLinus Torvalds * may become nonlinear and be shifted from prio_tree to nonlinear list 13501da177e4SLinus Torvalds * while the lock is dropped; but never shifted from list to prio_tree. 13511da177e4SLinus Torvalds * 13521da177e4SLinus Torvalds * In order to make forward progress despite restarting the search, 13531da177e4SLinus Torvalds * vm_truncate_count is used to mark a vma as now dealt with, so we can 13541da177e4SLinus Torvalds * quickly skip it next time around. Since the prio_tree search only 13551da177e4SLinus Torvalds * shows us those vmas affected by unmapping the range in question, we 13561da177e4SLinus Torvalds * can't efficiently keep all vmas in step with mapping->truncate_count: 13571da177e4SLinus Torvalds * so instead reset them all whenever it wraps back to 0 (then go to 1). 13581da177e4SLinus Torvalds * mapping->truncate_count and vma->vm_truncate_count are protected by 13591da177e4SLinus Torvalds * i_mmap_lock. 13601da177e4SLinus Torvalds * 13611da177e4SLinus Torvalds * In order to make forward progress despite repeatedly restarting some 1362ee39b37bSHugh Dickins * large vma, note the restart_addr from unmap_vmas when it breaks out: 13631da177e4SLinus Torvalds * and restart from that address when we reach that vma again. It might 13641da177e4SLinus Torvalds * have been split or merged, shrunk or extended, but never shifted: so 13651da177e4SLinus Torvalds * restart_addr remains valid so long as it remains in the vma's range. 13661da177e4SLinus Torvalds * unmap_mapping_range forces truncate_count to leap over page-aligned 13671da177e4SLinus Torvalds * values so we can save vma's restart_addr in its truncate_count field. 13681da177e4SLinus Torvalds */ 13691da177e4SLinus Torvalds #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 13701da177e4SLinus Torvalds 13711da177e4SLinus Torvalds static void reset_vma_truncate_counts(struct address_space *mapping) 13721da177e4SLinus Torvalds { 13731da177e4SLinus Torvalds struct vm_area_struct *vma; 13741da177e4SLinus Torvalds struct prio_tree_iter iter; 13751da177e4SLinus Torvalds 13761da177e4SLinus Torvalds vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 13771da177e4SLinus Torvalds vma->vm_truncate_count = 0; 13781da177e4SLinus Torvalds list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 13791da177e4SLinus Torvalds vma->vm_truncate_count = 0; 13801da177e4SLinus Torvalds } 13811da177e4SLinus Torvalds 13821da177e4SLinus Torvalds static int unmap_mapping_range_vma(struct vm_area_struct *vma, 13831da177e4SLinus Torvalds unsigned long start_addr, unsigned long end_addr, 13841da177e4SLinus Torvalds struct zap_details *details) 13851da177e4SLinus Torvalds { 13861da177e4SLinus Torvalds unsigned long restart_addr; 13871da177e4SLinus Torvalds int need_break; 13881da177e4SLinus Torvalds 13891da177e4SLinus Torvalds again: 13901da177e4SLinus Torvalds restart_addr = vma->vm_truncate_count; 13911da177e4SLinus Torvalds if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 13921da177e4SLinus Torvalds start_addr = restart_addr; 13931da177e4SLinus Torvalds if (start_addr >= end_addr) { 13941da177e4SLinus Torvalds /* Top of vma has been split off since last time */ 13951da177e4SLinus Torvalds vma->vm_truncate_count = details->truncate_count; 13961da177e4SLinus Torvalds return 0; 13971da177e4SLinus Torvalds } 13981da177e4SLinus Torvalds } 13991da177e4SLinus Torvalds 1400ee39b37bSHugh Dickins restart_addr = zap_page_range(vma, start_addr, 1401ee39b37bSHugh Dickins end_addr - start_addr, details); 14021da177e4SLinus Torvalds need_break = need_resched() || 14031da177e4SLinus Torvalds need_lockbreak(details->i_mmap_lock); 14041da177e4SLinus Torvalds 1405ee39b37bSHugh Dickins if (restart_addr >= end_addr) { 14061da177e4SLinus Torvalds /* We have now completed this vma: mark it so */ 14071da177e4SLinus Torvalds vma->vm_truncate_count = details->truncate_count; 14081da177e4SLinus Torvalds if (!need_break) 14091da177e4SLinus Torvalds return 0; 14101da177e4SLinus Torvalds } else { 14111da177e4SLinus Torvalds /* Note restart_addr in vma's truncate_count field */ 1412ee39b37bSHugh Dickins vma->vm_truncate_count = restart_addr; 14131da177e4SLinus Torvalds if (!need_break) 14141da177e4SLinus Torvalds goto again; 14151da177e4SLinus Torvalds } 14161da177e4SLinus Torvalds 14171da177e4SLinus Torvalds spin_unlock(details->i_mmap_lock); 14181da177e4SLinus Torvalds cond_resched(); 14191da177e4SLinus Torvalds spin_lock(details->i_mmap_lock); 14201da177e4SLinus Torvalds return -EINTR; 14211da177e4SLinus Torvalds } 14221da177e4SLinus Torvalds 14231da177e4SLinus Torvalds static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 14241da177e4SLinus Torvalds struct zap_details *details) 14251da177e4SLinus Torvalds { 14261da177e4SLinus Torvalds struct vm_area_struct *vma; 14271da177e4SLinus Torvalds struct prio_tree_iter iter; 14281da177e4SLinus Torvalds pgoff_t vba, vea, zba, zea; 14291da177e4SLinus Torvalds 14301da177e4SLinus Torvalds restart: 14311da177e4SLinus Torvalds vma_prio_tree_foreach(vma, &iter, root, 14321da177e4SLinus Torvalds details->first_index, details->last_index) { 14331da177e4SLinus Torvalds /* Skip quickly over those we have already dealt with */ 14341da177e4SLinus Torvalds if (vma->vm_truncate_count == details->truncate_count) 14351da177e4SLinus Torvalds continue; 14361da177e4SLinus Torvalds 14371da177e4SLinus Torvalds vba = vma->vm_pgoff; 14381da177e4SLinus Torvalds vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 14391da177e4SLinus Torvalds /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 14401da177e4SLinus Torvalds zba = details->first_index; 14411da177e4SLinus Torvalds if (zba < vba) 14421da177e4SLinus Torvalds zba = vba; 14431da177e4SLinus Torvalds zea = details->last_index; 14441da177e4SLinus Torvalds if (zea > vea) 14451da177e4SLinus Torvalds zea = vea; 14461da177e4SLinus Torvalds 14471da177e4SLinus Torvalds if (unmap_mapping_range_vma(vma, 14481da177e4SLinus Torvalds ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 14491da177e4SLinus Torvalds ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 14501da177e4SLinus Torvalds details) < 0) 14511da177e4SLinus Torvalds goto restart; 14521da177e4SLinus Torvalds } 14531da177e4SLinus Torvalds } 14541da177e4SLinus Torvalds 14551da177e4SLinus Torvalds static inline void unmap_mapping_range_list(struct list_head *head, 14561da177e4SLinus Torvalds struct zap_details *details) 14571da177e4SLinus Torvalds { 14581da177e4SLinus Torvalds struct vm_area_struct *vma; 14591da177e4SLinus Torvalds 14601da177e4SLinus Torvalds /* 14611da177e4SLinus Torvalds * In nonlinear VMAs there is no correspondence between virtual address 14621da177e4SLinus Torvalds * offset and file offset. So we must perform an exhaustive search 14631da177e4SLinus Torvalds * across *all* the pages in each nonlinear VMA, not just the pages 14641da177e4SLinus Torvalds * whose virtual address lies outside the file truncation point. 14651da177e4SLinus Torvalds */ 14661da177e4SLinus Torvalds restart: 14671da177e4SLinus Torvalds list_for_each_entry(vma, head, shared.vm_set.list) { 14681da177e4SLinus Torvalds /* Skip quickly over those we have already dealt with */ 14691da177e4SLinus Torvalds if (vma->vm_truncate_count == details->truncate_count) 14701da177e4SLinus Torvalds continue; 14711da177e4SLinus Torvalds details->nonlinear_vma = vma; 14721da177e4SLinus Torvalds if (unmap_mapping_range_vma(vma, vma->vm_start, 14731da177e4SLinus Torvalds vma->vm_end, details) < 0) 14741da177e4SLinus Torvalds goto restart; 14751da177e4SLinus Torvalds } 14761da177e4SLinus Torvalds } 14771da177e4SLinus Torvalds 14781da177e4SLinus Torvalds /** 14791da177e4SLinus Torvalds * unmap_mapping_range - unmap the portion of all mmaps 14801da177e4SLinus Torvalds * in the specified address_space corresponding to the specified 14811da177e4SLinus Torvalds * page range in the underlying file. 14823d41088fSMartin Waitz * @mapping: the address space containing mmaps to be unmapped. 14831da177e4SLinus Torvalds * @holebegin: byte in first page to unmap, relative to the start of 14841da177e4SLinus Torvalds * the underlying file. This will be rounded down to a PAGE_SIZE 14851da177e4SLinus Torvalds * boundary. Note that this is different from vmtruncate(), which 14861da177e4SLinus Torvalds * must keep the partial page. In contrast, we must get rid of 14871da177e4SLinus Torvalds * partial pages. 14881da177e4SLinus Torvalds * @holelen: size of prospective hole in bytes. This will be rounded 14891da177e4SLinus Torvalds * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 14901da177e4SLinus Torvalds * end of the file. 14911da177e4SLinus Torvalds * @even_cows: 1 when truncating a file, unmap even private COWed pages; 14921da177e4SLinus Torvalds * but 0 when invalidating pagecache, don't throw away private data. 14931da177e4SLinus Torvalds */ 14941da177e4SLinus Torvalds void unmap_mapping_range(struct address_space *mapping, 14951da177e4SLinus Torvalds loff_t const holebegin, loff_t const holelen, int even_cows) 14961da177e4SLinus Torvalds { 14971da177e4SLinus Torvalds struct zap_details details; 14981da177e4SLinus Torvalds pgoff_t hba = holebegin >> PAGE_SHIFT; 14991da177e4SLinus Torvalds pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 15001da177e4SLinus Torvalds 15011da177e4SLinus Torvalds /* Check for overflow. */ 15021da177e4SLinus Torvalds if (sizeof(holelen) > sizeof(hlen)) { 15031da177e4SLinus Torvalds long long holeend = 15041da177e4SLinus Torvalds (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 15051da177e4SLinus Torvalds if (holeend & ~(long long)ULONG_MAX) 15061da177e4SLinus Torvalds hlen = ULONG_MAX - hba + 1; 15071da177e4SLinus Torvalds } 15081da177e4SLinus Torvalds 15091da177e4SLinus Torvalds details.check_mapping = even_cows? NULL: mapping; 15101da177e4SLinus Torvalds details.nonlinear_vma = NULL; 15111da177e4SLinus Torvalds details.first_index = hba; 15121da177e4SLinus Torvalds details.last_index = hba + hlen - 1; 15131da177e4SLinus Torvalds if (details.last_index < details.first_index) 15141da177e4SLinus Torvalds details.last_index = ULONG_MAX; 15151da177e4SLinus Torvalds details.i_mmap_lock = &mapping->i_mmap_lock; 15161da177e4SLinus Torvalds 15171da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 15181da177e4SLinus Torvalds 15191da177e4SLinus Torvalds /* serialize i_size write against truncate_count write */ 15201da177e4SLinus Torvalds smp_wmb(); 15211da177e4SLinus Torvalds /* Protect against page faults, and endless unmapping loops */ 15221da177e4SLinus Torvalds mapping->truncate_count++; 15231da177e4SLinus Torvalds /* 15241da177e4SLinus Torvalds * For archs where spin_lock has inclusive semantics like ia64 15251da177e4SLinus Torvalds * this smp_mb() will prevent to read pagetable contents 15261da177e4SLinus Torvalds * before the truncate_count increment is visible to 15271da177e4SLinus Torvalds * other cpus. 15281da177e4SLinus Torvalds */ 15291da177e4SLinus Torvalds smp_mb(); 15301da177e4SLinus Torvalds if (unlikely(is_restart_addr(mapping->truncate_count))) { 15311da177e4SLinus Torvalds if (mapping->truncate_count == 0) 15321da177e4SLinus Torvalds reset_vma_truncate_counts(mapping); 15331da177e4SLinus Torvalds mapping->truncate_count++; 15341da177e4SLinus Torvalds } 15351da177e4SLinus Torvalds details.truncate_count = mapping->truncate_count; 15361da177e4SLinus Torvalds 15371da177e4SLinus Torvalds if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 15381da177e4SLinus Torvalds unmap_mapping_range_tree(&mapping->i_mmap, &details); 15391da177e4SLinus Torvalds if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 15401da177e4SLinus Torvalds unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 15411da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 15421da177e4SLinus Torvalds } 15431da177e4SLinus Torvalds EXPORT_SYMBOL(unmap_mapping_range); 15441da177e4SLinus Torvalds 15451da177e4SLinus Torvalds /* 15461da177e4SLinus Torvalds * Handle all mappings that got truncated by a "truncate()" 15471da177e4SLinus Torvalds * system call. 15481da177e4SLinus Torvalds * 15491da177e4SLinus Torvalds * NOTE! We have to be ready to update the memory sharing 15501da177e4SLinus Torvalds * between the file and the memory map for a potential last 15511da177e4SLinus Torvalds * incomplete page. Ugly, but necessary. 15521da177e4SLinus Torvalds */ 15531da177e4SLinus Torvalds int vmtruncate(struct inode * inode, loff_t offset) 15541da177e4SLinus Torvalds { 15551da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 15561da177e4SLinus Torvalds unsigned long limit; 15571da177e4SLinus Torvalds 15581da177e4SLinus Torvalds if (inode->i_size < offset) 15591da177e4SLinus Torvalds goto do_expand; 15601da177e4SLinus Torvalds /* 15611da177e4SLinus Torvalds * truncation of in-use swapfiles is disallowed - it would cause 15621da177e4SLinus Torvalds * subsequent swapout to scribble on the now-freed blocks. 15631da177e4SLinus Torvalds */ 15641da177e4SLinus Torvalds if (IS_SWAPFILE(inode)) 15651da177e4SLinus Torvalds goto out_busy; 15661da177e4SLinus Torvalds i_size_write(inode, offset); 15671da177e4SLinus Torvalds unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 15681da177e4SLinus Torvalds truncate_inode_pages(mapping, offset); 15691da177e4SLinus Torvalds goto out_truncate; 15701da177e4SLinus Torvalds 15711da177e4SLinus Torvalds do_expand: 15721da177e4SLinus Torvalds limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 15731da177e4SLinus Torvalds if (limit != RLIM_INFINITY && offset > limit) 15741da177e4SLinus Torvalds goto out_sig; 15751da177e4SLinus Torvalds if (offset > inode->i_sb->s_maxbytes) 15761da177e4SLinus Torvalds goto out_big; 15771da177e4SLinus Torvalds i_size_write(inode, offset); 15781da177e4SLinus Torvalds 15791da177e4SLinus Torvalds out_truncate: 15801da177e4SLinus Torvalds if (inode->i_op && inode->i_op->truncate) 15811da177e4SLinus Torvalds inode->i_op->truncate(inode); 15821da177e4SLinus Torvalds return 0; 15831da177e4SLinus Torvalds out_sig: 15841da177e4SLinus Torvalds send_sig(SIGXFSZ, current, 0); 15851da177e4SLinus Torvalds out_big: 15861da177e4SLinus Torvalds return -EFBIG; 15871da177e4SLinus Torvalds out_busy: 15881da177e4SLinus Torvalds return -ETXTBSY; 15891da177e4SLinus Torvalds } 15901da177e4SLinus Torvalds 15911da177e4SLinus Torvalds EXPORT_SYMBOL(vmtruncate); 15921da177e4SLinus Torvalds 15931da177e4SLinus Torvalds /* 15941da177e4SLinus Torvalds * Primitive swap readahead code. We simply read an aligned block of 15951da177e4SLinus Torvalds * (1 << page_cluster) entries in the swap area. This method is chosen 15961da177e4SLinus Torvalds * because it doesn't cost us any seek time. We also make sure to queue 15971da177e4SLinus Torvalds * the 'original' request together with the readahead ones... 15981da177e4SLinus Torvalds * 15991da177e4SLinus Torvalds * This has been extended to use the NUMA policies from the mm triggering 16001da177e4SLinus Torvalds * the readahead. 16011da177e4SLinus Torvalds * 16021da177e4SLinus Torvalds * Caller must hold down_read on the vma->vm_mm if vma is not NULL. 16031da177e4SLinus Torvalds */ 16041da177e4SLinus Torvalds void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) 16051da177e4SLinus Torvalds { 16061da177e4SLinus Torvalds #ifdef CONFIG_NUMA 16071da177e4SLinus Torvalds struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; 16081da177e4SLinus Torvalds #endif 16091da177e4SLinus Torvalds int i, num; 16101da177e4SLinus Torvalds struct page *new_page; 16111da177e4SLinus Torvalds unsigned long offset; 16121da177e4SLinus Torvalds 16131da177e4SLinus Torvalds /* 16141da177e4SLinus Torvalds * Get the number of handles we should do readahead io to. 16151da177e4SLinus Torvalds */ 16161da177e4SLinus Torvalds num = valid_swaphandles(entry, &offset); 16171da177e4SLinus Torvalds for (i = 0; i < num; offset++, i++) { 16181da177e4SLinus Torvalds /* Ok, do the async read-ahead now */ 16191da177e4SLinus Torvalds new_page = read_swap_cache_async(swp_entry(swp_type(entry), 16201da177e4SLinus Torvalds offset), vma, addr); 16211da177e4SLinus Torvalds if (!new_page) 16221da177e4SLinus Torvalds break; 16231da177e4SLinus Torvalds page_cache_release(new_page); 16241da177e4SLinus Torvalds #ifdef CONFIG_NUMA 16251da177e4SLinus Torvalds /* 16261da177e4SLinus Torvalds * Find the next applicable VMA for the NUMA policy. 16271da177e4SLinus Torvalds */ 16281da177e4SLinus Torvalds addr += PAGE_SIZE; 16291da177e4SLinus Torvalds if (addr == 0) 16301da177e4SLinus Torvalds vma = NULL; 16311da177e4SLinus Torvalds if (vma) { 16321da177e4SLinus Torvalds if (addr >= vma->vm_end) { 16331da177e4SLinus Torvalds vma = next_vma; 16341da177e4SLinus Torvalds next_vma = vma ? vma->vm_next : NULL; 16351da177e4SLinus Torvalds } 16361da177e4SLinus Torvalds if (vma && addr < vma->vm_start) 16371da177e4SLinus Torvalds vma = NULL; 16381da177e4SLinus Torvalds } else { 16391da177e4SLinus Torvalds if (next_vma && addr >= next_vma->vm_start) { 16401da177e4SLinus Torvalds vma = next_vma; 16411da177e4SLinus Torvalds next_vma = vma->vm_next; 16421da177e4SLinus Torvalds } 16431da177e4SLinus Torvalds } 16441da177e4SLinus Torvalds #endif 16451da177e4SLinus Torvalds } 16461da177e4SLinus Torvalds lru_add_drain(); /* Push any new pages onto the LRU now */ 16471da177e4SLinus Torvalds } 16481da177e4SLinus Torvalds 16491da177e4SLinus Torvalds /* 16508f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 16518f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 16528f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 16531da177e4SLinus Torvalds */ 165465500d23SHugh Dickins static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 165565500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 165665500d23SHugh Dickins int write_access, pte_t orig_pte) 16571da177e4SLinus Torvalds { 16588f4e2101SHugh Dickins spinlock_t *ptl; 16591da177e4SLinus Torvalds struct page *page; 166065500d23SHugh Dickins swp_entry_t entry; 16611da177e4SLinus Torvalds pte_t pte; 16621da177e4SLinus Torvalds int ret = VM_FAULT_MINOR; 16631da177e4SLinus Torvalds 16644c21e2f2SHugh Dickins if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 16658f4e2101SHugh Dickins goto out; 166665500d23SHugh Dickins 166765500d23SHugh Dickins entry = pte_to_swp_entry(orig_pte); 16681da177e4SLinus Torvalds page = lookup_swap_cache(entry); 16691da177e4SLinus Torvalds if (!page) { 16701da177e4SLinus Torvalds swapin_readahead(entry, address, vma); 16711da177e4SLinus Torvalds page = read_swap_cache_async(entry, vma, address); 16721da177e4SLinus Torvalds if (!page) { 16731da177e4SLinus Torvalds /* 16748f4e2101SHugh Dickins * Back out if somebody else faulted in this pte 16758f4e2101SHugh Dickins * while we released the pte lock. 16761da177e4SLinus Torvalds */ 16778f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 16781da177e4SLinus Torvalds if (likely(pte_same(*page_table, orig_pte))) 16791da177e4SLinus Torvalds ret = VM_FAULT_OOM; 168065500d23SHugh Dickins goto unlock; 16811da177e4SLinus Torvalds } 16821da177e4SLinus Torvalds 16831da177e4SLinus Torvalds /* Had to read the page from swap area: Major fault */ 16841da177e4SLinus Torvalds ret = VM_FAULT_MAJOR; 16851da177e4SLinus Torvalds inc_page_state(pgmajfault); 16861da177e4SLinus Torvalds grab_swap_token(); 16871da177e4SLinus Torvalds } 16881da177e4SLinus Torvalds 16891da177e4SLinus Torvalds mark_page_accessed(page); 16901da177e4SLinus Torvalds lock_page(page); 16911da177e4SLinus Torvalds 16921da177e4SLinus Torvalds /* 16938f4e2101SHugh Dickins * Back out if somebody else already faulted in this pte. 16941da177e4SLinus Torvalds */ 16958f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 16969e9bef07SHugh Dickins if (unlikely(!pte_same(*page_table, orig_pte))) 1697b8107480SKirill Korotaev goto out_nomap; 1698b8107480SKirill Korotaev 1699b8107480SKirill Korotaev if (unlikely(!PageUptodate(page))) { 1700b8107480SKirill Korotaev ret = VM_FAULT_SIGBUS; 1701b8107480SKirill Korotaev goto out_nomap; 17021da177e4SLinus Torvalds } 17031da177e4SLinus Torvalds 17041da177e4SLinus Torvalds /* The page isn't present yet, go ahead with the fault. */ 17051da177e4SLinus Torvalds 17064294621fSHugh Dickins inc_mm_counter(mm, anon_rss); 17071da177e4SLinus Torvalds pte = mk_pte(page, vma->vm_page_prot); 17081da177e4SLinus Torvalds if (write_access && can_share_swap_page(page)) { 17091da177e4SLinus Torvalds pte = maybe_mkwrite(pte_mkdirty(pte), vma); 17101da177e4SLinus Torvalds write_access = 0; 17111da177e4SLinus Torvalds } 17121da177e4SLinus Torvalds 17131da177e4SLinus Torvalds flush_icache_page(vma, page); 17141da177e4SLinus Torvalds set_pte_at(mm, address, page_table, pte); 17151da177e4SLinus Torvalds page_add_anon_rmap(page, vma, address); 17161da177e4SLinus Torvalds 1717c475a8abSHugh Dickins swap_free(entry); 1718c475a8abSHugh Dickins if (vm_swap_full()) 1719c475a8abSHugh Dickins remove_exclusive_swap_page(page); 1720c475a8abSHugh Dickins unlock_page(page); 1721c475a8abSHugh Dickins 17221da177e4SLinus Torvalds if (write_access) { 17231da177e4SLinus Torvalds if (do_wp_page(mm, vma, address, 17248f4e2101SHugh Dickins page_table, pmd, ptl, pte) == VM_FAULT_OOM) 17251da177e4SLinus Torvalds ret = VM_FAULT_OOM; 17261da177e4SLinus Torvalds goto out; 17271da177e4SLinus Torvalds } 17281da177e4SLinus Torvalds 17291da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 17301da177e4SLinus Torvalds update_mmu_cache(vma, address, pte); 17311da177e4SLinus Torvalds lazy_mmu_prot_update(pte); 173265500d23SHugh Dickins unlock: 17338f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 17341da177e4SLinus Torvalds out: 17351da177e4SLinus Torvalds return ret; 1736b8107480SKirill Korotaev out_nomap: 17378f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 1738b8107480SKirill Korotaev unlock_page(page); 1739b8107480SKirill Korotaev page_cache_release(page); 174065500d23SHugh Dickins return ret; 17411da177e4SLinus Torvalds } 17421da177e4SLinus Torvalds 17431da177e4SLinus Torvalds /* 17448f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 17458f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 17468f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 17471da177e4SLinus Torvalds */ 174865500d23SHugh Dickins static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 174965500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 175065500d23SHugh Dickins int write_access) 17511da177e4SLinus Torvalds { 17528f4e2101SHugh Dickins struct page *page; 17538f4e2101SHugh Dickins spinlock_t *ptl; 17541da177e4SLinus Torvalds pte_t entry; 17551da177e4SLinus Torvalds 17561da177e4SLinus Torvalds if (write_access) { 17571da177e4SLinus Torvalds /* Allocate our own private page. */ 17581da177e4SLinus Torvalds pte_unmap(page_table); 17591da177e4SLinus Torvalds 17601da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 176165500d23SHugh Dickins goto oom; 176265500d23SHugh Dickins page = alloc_zeroed_user_highpage(vma, address); 17631da177e4SLinus Torvalds if (!page) 176465500d23SHugh Dickins goto oom; 17651da177e4SLinus Torvalds 176665500d23SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 176765500d23SHugh Dickins entry = maybe_mkwrite(pte_mkdirty(entry), vma); 17688f4e2101SHugh Dickins 17698f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 17708f4e2101SHugh Dickins if (!pte_none(*page_table)) 17718f4e2101SHugh Dickins goto release; 17728f4e2101SHugh Dickins inc_mm_counter(mm, anon_rss); 17731da177e4SLinus Torvalds lru_cache_add_active(page); 17741da177e4SLinus Torvalds SetPageReferenced(page); 177565500d23SHugh Dickins page_add_anon_rmap(page, vma, address); 1776b5810039SNick Piggin } else { 17778f4e2101SHugh Dickins /* Map the ZERO_PAGE - vm_page_prot is readonly */ 17788f4e2101SHugh Dickins page = ZERO_PAGE(address); 17798f4e2101SHugh Dickins page_cache_get(page); 17808f4e2101SHugh Dickins entry = mk_pte(page, vma->vm_page_prot); 17818f4e2101SHugh Dickins 17824c21e2f2SHugh Dickins ptl = pte_lockptr(mm, pmd); 17838f4e2101SHugh Dickins spin_lock(ptl); 17848f4e2101SHugh Dickins if (!pte_none(*page_table)) 17858f4e2101SHugh Dickins goto release; 1786b5810039SNick Piggin inc_mm_counter(mm, file_rss); 1787b5810039SNick Piggin page_add_file_rmap(page); 17881da177e4SLinus Torvalds } 17891da177e4SLinus Torvalds 179065500d23SHugh Dickins set_pte_at(mm, address, page_table, entry); 17911da177e4SLinus Torvalds 17921da177e4SLinus Torvalds /* No need to invalidate - it was non-present before */ 179365500d23SHugh Dickins update_mmu_cache(vma, address, entry); 17941da177e4SLinus Torvalds lazy_mmu_prot_update(entry); 179565500d23SHugh Dickins unlock: 17968f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 17971da177e4SLinus Torvalds return VM_FAULT_MINOR; 17988f4e2101SHugh Dickins release: 17998f4e2101SHugh Dickins page_cache_release(page); 18008f4e2101SHugh Dickins goto unlock; 180165500d23SHugh Dickins oom: 18021da177e4SLinus Torvalds return VM_FAULT_OOM; 18031da177e4SLinus Torvalds } 18041da177e4SLinus Torvalds 18051da177e4SLinus Torvalds /* 18061da177e4SLinus Torvalds * do_no_page() tries to create a new page mapping. It aggressively 18071da177e4SLinus Torvalds * tries to share with existing pages, but makes a separate copy if 18081da177e4SLinus Torvalds * the "write_access" parameter is true in order to avoid the next 18091da177e4SLinus Torvalds * page fault. 18101da177e4SLinus Torvalds * 18111da177e4SLinus Torvalds * As this is called only for pages that do not currently exist, we 18121da177e4SLinus Torvalds * do not need to flush old virtual caches or the TLB. 18131da177e4SLinus Torvalds * 18148f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 18158f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 18168f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 18171da177e4SLinus Torvalds */ 181865500d23SHugh Dickins static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 181965500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 182065500d23SHugh Dickins int write_access) 18211da177e4SLinus Torvalds { 18228f4e2101SHugh Dickins spinlock_t *ptl; 18231da177e4SLinus Torvalds struct page *new_page; 18241da177e4SLinus Torvalds struct address_space *mapping = NULL; 18251da177e4SLinus Torvalds pte_t entry; 18261da177e4SLinus Torvalds unsigned int sequence = 0; 18271da177e4SLinus Torvalds int ret = VM_FAULT_MINOR; 18281da177e4SLinus Torvalds int anon = 0; 18291da177e4SLinus Torvalds 18301da177e4SLinus Torvalds pte_unmap(page_table); 18311da177e4SLinus Torvalds 18321da177e4SLinus Torvalds if (vma->vm_file) { 18331da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 18341da177e4SLinus Torvalds sequence = mapping->truncate_count; 18351da177e4SLinus Torvalds smp_rmb(); /* serializes i_size against truncate_count */ 18361da177e4SLinus Torvalds } 18371da177e4SLinus Torvalds retry: 18381da177e4SLinus Torvalds new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 18391da177e4SLinus Torvalds /* 18401da177e4SLinus Torvalds * No smp_rmb is needed here as long as there's a full 18411da177e4SLinus Torvalds * spin_lock/unlock sequence inside the ->nopage callback 18421da177e4SLinus Torvalds * (for the pagecache lookup) that acts as an implicit 18431da177e4SLinus Torvalds * smp_mb() and prevents the i_size read to happen 18441da177e4SLinus Torvalds * after the next truncate_count read. 18451da177e4SLinus Torvalds */ 18461da177e4SLinus Torvalds 18471da177e4SLinus Torvalds /* no page was available -- either SIGBUS or OOM */ 18481da177e4SLinus Torvalds if (new_page == NOPAGE_SIGBUS) 18491da177e4SLinus Torvalds return VM_FAULT_SIGBUS; 18501da177e4SLinus Torvalds if (new_page == NOPAGE_OOM) 18511da177e4SLinus Torvalds return VM_FAULT_OOM; 18521da177e4SLinus Torvalds 18531da177e4SLinus Torvalds /* 18541da177e4SLinus Torvalds * Should we do an early C-O-W break? 18551da177e4SLinus Torvalds */ 18561da177e4SLinus Torvalds if (write_access && !(vma->vm_flags & VM_SHARED)) { 18571da177e4SLinus Torvalds struct page *page; 18581da177e4SLinus Torvalds 18591da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 18601da177e4SLinus Torvalds goto oom; 18611da177e4SLinus Torvalds page = alloc_page_vma(GFP_HIGHUSER, vma, address); 18621da177e4SLinus Torvalds if (!page) 18631da177e4SLinus Torvalds goto oom; 18641da177e4SLinus Torvalds copy_user_highpage(page, new_page, address); 18651da177e4SLinus Torvalds page_cache_release(new_page); 18661da177e4SLinus Torvalds new_page = page; 18671da177e4SLinus Torvalds anon = 1; 18681da177e4SLinus Torvalds } 18691da177e4SLinus Torvalds 18708f4e2101SHugh Dickins page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 18711da177e4SLinus Torvalds /* 18721da177e4SLinus Torvalds * For a file-backed vma, someone could have truncated or otherwise 18731da177e4SLinus Torvalds * invalidated this page. If unmap_mapping_range got called, 18741da177e4SLinus Torvalds * retry getting the page. 18751da177e4SLinus Torvalds */ 18761da177e4SLinus Torvalds if (mapping && unlikely(sequence != mapping->truncate_count)) { 18778f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 18781da177e4SLinus Torvalds page_cache_release(new_page); 187965500d23SHugh Dickins cond_resched(); 188065500d23SHugh Dickins sequence = mapping->truncate_count; 188165500d23SHugh Dickins smp_rmb(); 18821da177e4SLinus Torvalds goto retry; 18831da177e4SLinus Torvalds } 18841da177e4SLinus Torvalds 18851da177e4SLinus Torvalds /* 18861da177e4SLinus Torvalds * This silly early PAGE_DIRTY setting removes a race 18871da177e4SLinus Torvalds * due to the bad i386 page protection. But it's valid 18881da177e4SLinus Torvalds * for other architectures too. 18891da177e4SLinus Torvalds * 18901da177e4SLinus Torvalds * Note that if write_access is true, we either now have 18911da177e4SLinus Torvalds * an exclusive copy of the page, or this is a shared mapping, 18921da177e4SLinus Torvalds * so we can make it writable and dirty to avoid having to 18931da177e4SLinus Torvalds * handle that later. 18941da177e4SLinus Torvalds */ 18951da177e4SLinus Torvalds /* Only go through if we didn't race with anybody else... */ 18961da177e4SLinus Torvalds if (pte_none(*page_table)) { 18971da177e4SLinus Torvalds flush_icache_page(vma, new_page); 18981da177e4SLinus Torvalds entry = mk_pte(new_page, vma->vm_page_prot); 18991da177e4SLinus Torvalds if (write_access) 19001da177e4SLinus Torvalds entry = maybe_mkwrite(pte_mkdirty(entry), vma); 19011da177e4SLinus Torvalds set_pte_at(mm, address, page_table, entry); 19021da177e4SLinus Torvalds if (anon) { 19034294621fSHugh Dickins inc_mm_counter(mm, anon_rss); 19041da177e4SLinus Torvalds lru_cache_add_active(new_page); 19051da177e4SLinus Torvalds page_add_anon_rmap(new_page, vma, address); 1906b5810039SNick Piggin } else if (!(vma->vm_flags & VM_RESERVED)) { 19074294621fSHugh Dickins inc_mm_counter(mm, file_rss); 19081da177e4SLinus Torvalds page_add_file_rmap(new_page); 19094294621fSHugh Dickins } 19101da177e4SLinus Torvalds } else { 19111da177e4SLinus Torvalds /* One of our sibling threads was faster, back out. */ 19121da177e4SLinus Torvalds page_cache_release(new_page); 191365500d23SHugh Dickins goto unlock; 19141da177e4SLinus Torvalds } 19151da177e4SLinus Torvalds 19161da177e4SLinus Torvalds /* no need to invalidate: a not-present page shouldn't be cached */ 19171da177e4SLinus Torvalds update_mmu_cache(vma, address, entry); 19181da177e4SLinus Torvalds lazy_mmu_prot_update(entry); 191965500d23SHugh Dickins unlock: 19208f4e2101SHugh Dickins pte_unmap_unlock(page_table, ptl); 19211da177e4SLinus Torvalds return ret; 19221da177e4SLinus Torvalds oom: 19231da177e4SLinus Torvalds page_cache_release(new_page); 192465500d23SHugh Dickins return VM_FAULT_OOM; 19251da177e4SLinus Torvalds } 19261da177e4SLinus Torvalds 19271da177e4SLinus Torvalds /* 19281da177e4SLinus Torvalds * Fault of a previously existing named mapping. Repopulate the pte 19291da177e4SLinus Torvalds * from the encoded file_pte if possible. This enables swappable 19301da177e4SLinus Torvalds * nonlinear vmas. 19318f4e2101SHugh Dickins * 19328f4e2101SHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 19338f4e2101SHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 19348f4e2101SHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 19351da177e4SLinus Torvalds */ 19361da177e4SLinus Torvalds static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma, 193765500d23SHugh Dickins unsigned long address, pte_t *page_table, pmd_t *pmd, 193865500d23SHugh Dickins int write_access, pte_t orig_pte) 19391da177e4SLinus Torvalds { 194065500d23SHugh Dickins pgoff_t pgoff; 19411da177e4SLinus Torvalds int err; 19421da177e4SLinus Torvalds 19434c21e2f2SHugh Dickins if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 19448f4e2101SHugh Dickins return VM_FAULT_MINOR; 19451da177e4SLinus Torvalds 194665500d23SHugh Dickins if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { 194765500d23SHugh Dickins /* 194865500d23SHugh Dickins * Page table corrupted: show pte and kill process. 194965500d23SHugh Dickins */ 1950b5810039SNick Piggin print_bad_pte(vma, orig_pte, address); 195165500d23SHugh Dickins return VM_FAULT_OOM; 195265500d23SHugh Dickins } 195365500d23SHugh Dickins /* We can then assume vm->vm_ops && vma->vm_ops->populate */ 195465500d23SHugh Dickins 195565500d23SHugh Dickins pgoff = pte_to_pgoff(orig_pte); 195665500d23SHugh Dickins err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, 195765500d23SHugh Dickins vma->vm_page_prot, pgoff, 0); 19581da177e4SLinus Torvalds if (err == -ENOMEM) 19591da177e4SLinus Torvalds return VM_FAULT_OOM; 19601da177e4SLinus Torvalds if (err) 19611da177e4SLinus Torvalds return VM_FAULT_SIGBUS; 19621da177e4SLinus Torvalds return VM_FAULT_MAJOR; 19631da177e4SLinus Torvalds } 19641da177e4SLinus Torvalds 19651da177e4SLinus Torvalds /* 19661da177e4SLinus Torvalds * These routines also need to handle stuff like marking pages dirty 19671da177e4SLinus Torvalds * and/or accessed for architectures that don't do it in hardware (most 19681da177e4SLinus Torvalds * RISC architectures). The early dirtying is also good on the i386. 19691da177e4SLinus Torvalds * 19701da177e4SLinus Torvalds * There is also a hook called "update_mmu_cache()" that architectures 19711da177e4SLinus Torvalds * with external mmu caches can use to update those (ie the Sparc or 19721da177e4SLinus Torvalds * PowerPC hashed page tables that act as extended TLBs). 19731da177e4SLinus Torvalds * 1974c74df32cSHugh Dickins * We enter with non-exclusive mmap_sem (to exclude vma changes, 1975c74df32cSHugh Dickins * but allow concurrent faults), and pte mapped but not yet locked. 1976c74df32cSHugh Dickins * We return with mmap_sem still held, but pte unmapped and unlocked. 19771da177e4SLinus Torvalds */ 19781da177e4SLinus Torvalds static inline int handle_pte_fault(struct mm_struct *mm, 19791da177e4SLinus Torvalds struct vm_area_struct *vma, unsigned long address, 198065500d23SHugh Dickins pte_t *pte, pmd_t *pmd, int write_access) 19811da177e4SLinus Torvalds { 19821da177e4SLinus Torvalds pte_t entry; 1983*1a44e149SAndrea Arcangeli pte_t old_entry; 19848f4e2101SHugh Dickins spinlock_t *ptl; 19851da177e4SLinus Torvalds 1986*1a44e149SAndrea Arcangeli old_entry = entry = *pte; 19871da177e4SLinus Torvalds if (!pte_present(entry)) { 198865500d23SHugh Dickins if (pte_none(entry)) { 198965500d23SHugh Dickins if (!vma->vm_ops || !vma->vm_ops->nopage) 199065500d23SHugh Dickins return do_anonymous_page(mm, vma, address, 199165500d23SHugh Dickins pte, pmd, write_access); 199265500d23SHugh Dickins return do_no_page(mm, vma, address, 199365500d23SHugh Dickins pte, pmd, write_access); 199465500d23SHugh Dickins } 19951da177e4SLinus Torvalds if (pte_file(entry)) 199665500d23SHugh Dickins return do_file_page(mm, vma, address, 199765500d23SHugh Dickins pte, pmd, write_access, entry); 199865500d23SHugh Dickins return do_swap_page(mm, vma, address, 199965500d23SHugh Dickins pte, pmd, write_access, entry); 20001da177e4SLinus Torvalds } 20011da177e4SLinus Torvalds 20024c21e2f2SHugh Dickins ptl = pte_lockptr(mm, pmd); 20038f4e2101SHugh Dickins spin_lock(ptl); 20048f4e2101SHugh Dickins if (unlikely(!pte_same(*pte, entry))) 20058f4e2101SHugh Dickins goto unlock; 20061da177e4SLinus Torvalds if (write_access) { 20071da177e4SLinus Torvalds if (!pte_write(entry)) 20088f4e2101SHugh Dickins return do_wp_page(mm, vma, address, 20098f4e2101SHugh Dickins pte, pmd, ptl, entry); 20101da177e4SLinus Torvalds entry = pte_mkdirty(entry); 20111da177e4SLinus Torvalds } 20121da177e4SLinus Torvalds entry = pte_mkyoung(entry); 2013*1a44e149SAndrea Arcangeli if (!pte_same(old_entry, entry)) { 20141da177e4SLinus Torvalds ptep_set_access_flags(vma, address, pte, entry, write_access); 20151da177e4SLinus Torvalds update_mmu_cache(vma, address, entry); 20161da177e4SLinus Torvalds lazy_mmu_prot_update(entry); 2017*1a44e149SAndrea Arcangeli } else { 2018*1a44e149SAndrea Arcangeli /* 2019*1a44e149SAndrea Arcangeli * This is needed only for protection faults but the arch code 2020*1a44e149SAndrea Arcangeli * is not yet telling us if this is a protection fault or not. 2021*1a44e149SAndrea Arcangeli * This still avoids useless tlb flushes for .text page faults 2022*1a44e149SAndrea Arcangeli * with threads. 2023*1a44e149SAndrea Arcangeli */ 2024*1a44e149SAndrea Arcangeli if (write_access) 2025*1a44e149SAndrea Arcangeli flush_tlb_page(vma, address); 2026*1a44e149SAndrea Arcangeli } 20278f4e2101SHugh Dickins unlock: 20288f4e2101SHugh Dickins pte_unmap_unlock(pte, ptl); 20291da177e4SLinus Torvalds return VM_FAULT_MINOR; 20301da177e4SLinus Torvalds } 20311da177e4SLinus Torvalds 20321da177e4SLinus Torvalds /* 20331da177e4SLinus Torvalds * By the time we get here, we already hold the mm semaphore 20341da177e4SLinus Torvalds */ 2035f33ea7f4SNick Piggin int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 20361da177e4SLinus Torvalds unsigned long address, int write_access) 20371da177e4SLinus Torvalds { 20381da177e4SLinus Torvalds pgd_t *pgd; 20391da177e4SLinus Torvalds pud_t *pud; 20401da177e4SLinus Torvalds pmd_t *pmd; 20411da177e4SLinus Torvalds pte_t *pte; 20421da177e4SLinus Torvalds 20431da177e4SLinus Torvalds __set_current_state(TASK_RUNNING); 20441da177e4SLinus Torvalds 20451da177e4SLinus Torvalds inc_page_state(pgfault); 20461da177e4SLinus Torvalds 2047ac9b9c66SHugh Dickins if (unlikely(is_vm_hugetlb_page(vma))) 2048ac9b9c66SHugh Dickins return hugetlb_fault(mm, vma, address, write_access); 20491da177e4SLinus Torvalds 20501da177e4SLinus Torvalds pgd = pgd_offset(mm, address); 20511da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, address); 20521da177e4SLinus Torvalds if (!pud) 2053c74df32cSHugh Dickins return VM_FAULT_OOM; 20541da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, address); 20551da177e4SLinus Torvalds if (!pmd) 2056c74df32cSHugh Dickins return VM_FAULT_OOM; 20571da177e4SLinus Torvalds pte = pte_alloc_map(mm, pmd, address); 20581da177e4SLinus Torvalds if (!pte) 2059c74df32cSHugh Dickins return VM_FAULT_OOM; 20601da177e4SLinus Torvalds 206165500d23SHugh Dickins return handle_pte_fault(mm, vma, address, pte, pmd, write_access); 20621da177e4SLinus Torvalds } 20631da177e4SLinus Torvalds 20641da177e4SLinus Torvalds #ifndef __PAGETABLE_PUD_FOLDED 20651da177e4SLinus Torvalds /* 20661da177e4SLinus Torvalds * Allocate page upper directory. 2067872fec16SHugh Dickins * We've already handled the fast-path in-line. 20681da177e4SLinus Torvalds */ 20691bb3630eSHugh Dickins int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 20701da177e4SLinus Torvalds { 2071c74df32cSHugh Dickins pud_t *new = pud_alloc_one(mm, address); 2072c74df32cSHugh Dickins if (!new) 20731bb3630eSHugh Dickins return -ENOMEM; 20741da177e4SLinus Torvalds 2075872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 20761bb3630eSHugh Dickins if (pgd_present(*pgd)) /* Another has populated it */ 20771da177e4SLinus Torvalds pud_free(new); 20781bb3630eSHugh Dickins else 20791da177e4SLinus Torvalds pgd_populate(mm, pgd, new); 2080872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 20811bb3630eSHugh Dickins return 0; 20821da177e4SLinus Torvalds } 20831da177e4SLinus Torvalds #endif /* __PAGETABLE_PUD_FOLDED */ 20841da177e4SLinus Torvalds 20851da177e4SLinus Torvalds #ifndef __PAGETABLE_PMD_FOLDED 20861da177e4SLinus Torvalds /* 20871da177e4SLinus Torvalds * Allocate page middle directory. 2088872fec16SHugh Dickins * We've already handled the fast-path in-line. 20891da177e4SLinus Torvalds */ 20901bb3630eSHugh Dickins int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 20911da177e4SLinus Torvalds { 2092c74df32cSHugh Dickins pmd_t *new = pmd_alloc_one(mm, address); 2093c74df32cSHugh Dickins if (!new) 20941bb3630eSHugh Dickins return -ENOMEM; 20951da177e4SLinus Torvalds 2096872fec16SHugh Dickins spin_lock(&mm->page_table_lock); 20971da177e4SLinus Torvalds #ifndef __ARCH_HAS_4LEVEL_HACK 20981bb3630eSHugh Dickins if (pud_present(*pud)) /* Another has populated it */ 20991da177e4SLinus Torvalds pmd_free(new); 21001bb3630eSHugh Dickins else 21011da177e4SLinus Torvalds pud_populate(mm, pud, new); 21021da177e4SLinus Torvalds #else 21031bb3630eSHugh Dickins if (pgd_present(*pud)) /* Another has populated it */ 21041da177e4SLinus Torvalds pmd_free(new); 21051bb3630eSHugh Dickins else 21061da177e4SLinus Torvalds pgd_populate(mm, pud, new); 21071da177e4SLinus Torvalds #endif /* __ARCH_HAS_4LEVEL_HACK */ 2108872fec16SHugh Dickins spin_unlock(&mm->page_table_lock); 21091bb3630eSHugh Dickins return 0; 21101da177e4SLinus Torvalds } 21111da177e4SLinus Torvalds #endif /* __PAGETABLE_PMD_FOLDED */ 21121da177e4SLinus Torvalds 21131da177e4SLinus Torvalds int make_pages_present(unsigned long addr, unsigned long end) 21141da177e4SLinus Torvalds { 21151da177e4SLinus Torvalds int ret, len, write; 21161da177e4SLinus Torvalds struct vm_area_struct * vma; 21171da177e4SLinus Torvalds 21181da177e4SLinus Torvalds vma = find_vma(current->mm, addr); 21191da177e4SLinus Torvalds if (!vma) 21201da177e4SLinus Torvalds return -1; 21211da177e4SLinus Torvalds write = (vma->vm_flags & VM_WRITE) != 0; 21221da177e4SLinus Torvalds if (addr >= end) 21231da177e4SLinus Torvalds BUG(); 21241da177e4SLinus Torvalds if (end > vma->vm_end) 21251da177e4SLinus Torvalds BUG(); 21261da177e4SLinus Torvalds len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; 21271da177e4SLinus Torvalds ret = get_user_pages(current, current->mm, addr, 21281da177e4SLinus Torvalds len, write, 0, NULL, NULL); 21291da177e4SLinus Torvalds if (ret < 0) 21301da177e4SLinus Torvalds return ret; 21311da177e4SLinus Torvalds return ret == len ? 0 : -1; 21321da177e4SLinus Torvalds } 21331da177e4SLinus Torvalds 21341da177e4SLinus Torvalds /* 21351da177e4SLinus Torvalds * Map a vmalloc()-space virtual address to the physical page. 21361da177e4SLinus Torvalds */ 21371da177e4SLinus Torvalds struct page * vmalloc_to_page(void * vmalloc_addr) 21381da177e4SLinus Torvalds { 21391da177e4SLinus Torvalds unsigned long addr = (unsigned long) vmalloc_addr; 21401da177e4SLinus Torvalds struct page *page = NULL; 21411da177e4SLinus Torvalds pgd_t *pgd = pgd_offset_k(addr); 21421da177e4SLinus Torvalds pud_t *pud; 21431da177e4SLinus Torvalds pmd_t *pmd; 21441da177e4SLinus Torvalds pte_t *ptep, pte; 21451da177e4SLinus Torvalds 21461da177e4SLinus Torvalds if (!pgd_none(*pgd)) { 21471da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 21481da177e4SLinus Torvalds if (!pud_none(*pud)) { 21491da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 21501da177e4SLinus Torvalds if (!pmd_none(*pmd)) { 21511da177e4SLinus Torvalds ptep = pte_offset_map(pmd, addr); 21521da177e4SLinus Torvalds pte = *ptep; 21531da177e4SLinus Torvalds if (pte_present(pte)) 21541da177e4SLinus Torvalds page = pte_page(pte); 21551da177e4SLinus Torvalds pte_unmap(ptep); 21561da177e4SLinus Torvalds } 21571da177e4SLinus Torvalds } 21581da177e4SLinus Torvalds } 21591da177e4SLinus Torvalds return page; 21601da177e4SLinus Torvalds } 21611da177e4SLinus Torvalds 21621da177e4SLinus Torvalds EXPORT_SYMBOL(vmalloc_to_page); 21631da177e4SLinus Torvalds 21641da177e4SLinus Torvalds /* 21651da177e4SLinus Torvalds * Map a vmalloc()-space virtual address to the physical page frame number. 21661da177e4SLinus Torvalds */ 21671da177e4SLinus Torvalds unsigned long vmalloc_to_pfn(void * vmalloc_addr) 21681da177e4SLinus Torvalds { 21691da177e4SLinus Torvalds return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 21701da177e4SLinus Torvalds } 21711da177e4SLinus Torvalds 21721da177e4SLinus Torvalds EXPORT_SYMBOL(vmalloc_to_pfn); 21731da177e4SLinus Torvalds 21741da177e4SLinus Torvalds #if !defined(__HAVE_ARCH_GATE_AREA) 21751da177e4SLinus Torvalds 21761da177e4SLinus Torvalds #if defined(AT_SYSINFO_EHDR) 21775ce7852cSAdrian Bunk static struct vm_area_struct gate_vma; 21781da177e4SLinus Torvalds 21791da177e4SLinus Torvalds static int __init gate_vma_init(void) 21801da177e4SLinus Torvalds { 21811da177e4SLinus Torvalds gate_vma.vm_mm = NULL; 21821da177e4SLinus Torvalds gate_vma.vm_start = FIXADDR_USER_START; 21831da177e4SLinus Torvalds gate_vma.vm_end = FIXADDR_USER_END; 21841da177e4SLinus Torvalds gate_vma.vm_page_prot = PAGE_READONLY; 2185b5810039SNick Piggin gate_vma.vm_flags = VM_RESERVED; 21861da177e4SLinus Torvalds return 0; 21871da177e4SLinus Torvalds } 21881da177e4SLinus Torvalds __initcall(gate_vma_init); 21891da177e4SLinus Torvalds #endif 21901da177e4SLinus Torvalds 21911da177e4SLinus Torvalds struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 21921da177e4SLinus Torvalds { 21931da177e4SLinus Torvalds #ifdef AT_SYSINFO_EHDR 21941da177e4SLinus Torvalds return &gate_vma; 21951da177e4SLinus Torvalds #else 21961da177e4SLinus Torvalds return NULL; 21971da177e4SLinus Torvalds #endif 21981da177e4SLinus Torvalds } 21991da177e4SLinus Torvalds 22001da177e4SLinus Torvalds int in_gate_area_no_task(unsigned long addr) 22011da177e4SLinus Torvalds { 22021da177e4SLinus Torvalds #ifdef AT_SYSINFO_EHDR 22031da177e4SLinus Torvalds if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 22041da177e4SLinus Torvalds return 1; 22051da177e4SLinus Torvalds #endif 22061da177e4SLinus Torvalds return 0; 22071da177e4SLinus Torvalds } 22081da177e4SLinus Torvalds 22091da177e4SLinus Torvalds #endif /* __HAVE_ARCH_GATE_AREA */ 2210