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author | cl349@freefall.cl.cam.ac.uk <cl349@freefall.cl.cam.ac.uk> | 2004-08-27 15:13:26 +0000 |
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committer | cl349@freefall.cl.cam.ac.uk <cl349@freefall.cl.cam.ac.uk> | 2004-08-27 15:13:26 +0000 |
commit | c50cb033fa1de3ecc96d84a2a7cc78766e9096dc (patch) | |
tree | 9b2cd18f92c7ea06cfb007f36e78d30de09f3147 /linux-2.6.8.1-xen-sparse | |
parent | f1cd150e1f99263722fe840b4e039ec8e14dca48 (diff) | |
download | xen-c50cb033fa1de3ecc96d84a2a7cc78766e9096dc.tar.gz xen-c50cb033fa1de3ecc96d84a2a7cc78766e9096dc.tar.bz2 xen-c50cb033fa1de3ecc96d84a2a7cc78766e9096dc.zip |
bitkeeper revision 1.1159.57.2 (412f4f96lcvl1zNFbliRXwffVN2DFg)
Add ptep_establish_new and use in page fault path.
Diffstat (limited to 'linux-2.6.8.1-xen-sparse')
-rw-r--r-- | linux-2.6.8.1-xen-sparse/include/asm-generic/pgtable.h | 136 | ||||
-rw-r--r-- | linux-2.6.8.1-xen-sparse/include/asm-xen/asm-i386/pgtable.h | 19 | ||||
-rw-r--r-- | linux-2.6.8.1-xen-sparse/mm/memory.c | 1822 |
3 files changed, 1977 insertions, 0 deletions
diff --git a/linux-2.6.8.1-xen-sparse/include/asm-generic/pgtable.h b/linux-2.6.8.1-xen-sparse/include/asm-generic/pgtable.h new file mode 100644 index 0000000000..e7d6c37eea --- /dev/null +++ b/linux-2.6.8.1-xen-sparse/include/asm-generic/pgtable.h @@ -0,0 +1,136 @@ +#ifndef _ASM_GENERIC_PGTABLE_H +#define _ASM_GENERIC_PGTABLE_H + +#ifndef __HAVE_ARCH_PTEP_ESTABLISH +/* + * Establish a new mapping: + * - flush the old one + * - update the page tables + * - inform the TLB about the new one + * + * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock. + * + * Note: the old pte is known to not be writable, so we don't need to + * worry about dirty bits etc getting lost. + */ +#define ptep_establish(__vma, __address, __ptep, __entry) \ +do { \ + set_pte(__ptep, __entry); \ + flush_tlb_page(__vma, __address); \ +} while (0) +#endif + +#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS +/* + * Largely same as above, but only sets the access flags (dirty, + * accessed, and writable). Furthermore, we know it always gets set + * to a "more permissive" setting, which allows most architectures + * to optimize this. + */ +#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \ +do { \ + set_pte(__ptep, __entry); \ + flush_tlb_page(__vma, __address); \ +} while (0) +#endif + +#ifndef __HAVE_ARCH_PTEP_ESTABLISH_NEW +#define ptep_establish_new(__vma, __address, __ptep, __entry) \ +do { \ + set_pte(__ptep, __entry); \ +} while (0) +#endif + +#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG +static inline int ptep_test_and_clear_young(pte_t *ptep) +{ + pte_t pte = *ptep; + if (!pte_young(pte)) + return 0; + set_pte(ptep, pte_mkold(pte)); + return 1; +} +#endif + +#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH +#define ptep_clear_flush_young(__vma, __address, __ptep) \ +({ \ + int __young = ptep_test_and_clear_young(__ptep); \ + if (__young) \ + flush_tlb_page(__vma, __address); \ + __young; \ +}) +#endif + +#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY +static inline int ptep_test_and_clear_dirty(pte_t *ptep) +{ + pte_t pte = *ptep; + if (!pte_dirty(pte)) + return 0; + set_pte(ptep, pte_mkclean(pte)); + return 1; +} +#endif + +#ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH +#define ptep_clear_flush_dirty(__vma, __address, __ptep) \ +({ \ + int __dirty = ptep_test_and_clear_dirty(__ptep); \ + if (__dirty) \ + flush_tlb_page(__vma, __address); \ + __dirty; \ +}) +#endif + +#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR +static inline pte_t ptep_get_and_clear(pte_t *ptep) +{ + pte_t pte = *ptep; + pte_clear(ptep); + return pte; +} +#endif + +#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH +#define ptep_clear_flush(__vma, __address, __ptep) \ +({ \ + pte_t __pte = ptep_get_and_clear(__ptep); \ + flush_tlb_page(__vma, __address); \ + __pte; \ +}) +#endif + +#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT +static inline void ptep_set_wrprotect(pte_t *ptep) +{ + pte_t old_pte = *ptep; + set_pte(ptep, pte_wrprotect(old_pte)); +} +#endif + +#ifndef __HAVE_ARCH_PTEP_MKDIRTY +static inline void ptep_mkdirty(pte_t *ptep) +{ + pte_t old_pte = *ptep; + set_pte(ptep, pte_mkdirty(old_pte)); +} +#endif + +#ifndef __HAVE_ARCH_PTE_SAME +#define pte_same(A,B) (pte_val(A) == pte_val(B)) +#endif + +#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY +#define page_test_and_clear_dirty(page) (0) +#endif + +#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG +#define page_test_and_clear_young(page) (0) +#endif + +#ifndef __HAVE_ARCH_PGD_OFFSET_GATE +#define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) +#endif + +#endif /* _ASM_GENERIC_PGTABLE_H */ diff --git a/linux-2.6.8.1-xen-sparse/include/asm-xen/asm-i386/pgtable.h b/linux-2.6.8.1-xen-sparse/include/asm-xen/asm-i386/pgtable.h index 6721e85aaf..a84b1a2308 100644 --- a/linux-2.6.8.1-xen-sparse/include/asm-xen/asm-i386/pgtable.h +++ b/linux-2.6.8.1-xen-sparse/include/asm-xen/asm-i386/pgtable.h @@ -436,12 +436,31 @@ extern pte_t *lookup_address(unsigned long address); HYPERVISOR_update_va_mapping(address>>PAGE_SHIFT, entry, UVMF_INVLPG); \ } else { \ xen_l1_entry_update((__ptep), (__entry).pte_low); \ + flush_tlb_page(__vma, __address); \ } \ } \ } while (0) #endif +#define __HAVE_ARCH_PTEP_ESTABLISH +#define ptep_establish(__vma, __address, __ptep, __entry) \ +do { \ + ptep_set_access_flags(__vma, __address, __ptep, __entry, 1); \ +} while (0) + +#define __HAVE_ARCH_PTEP_ESTABLISH_NEW +#define ptep_establish_new(__vma, __address, __ptep, __entry) \ +do { \ + if ( likely((__vma)->vm_mm == current->mm) ) { \ + xen_flush_page_update_queue(); \ + HYPERVISOR_update_va_mapping((__address)>>PAGE_SHIFT, \ + __entry, 0); \ + } else { \ + xen_l1_entry_update((__ptep), (__entry).pte_low); \ + } \ +} while (0) + /* Encode and de-code a swap entry */ #define __swp_type(x) (((x).val >> 1) & 0x1f) #define __swp_offset(x) ((x).val >> 8) diff --git a/linux-2.6.8.1-xen-sparse/mm/memory.c b/linux-2.6.8.1-xen-sparse/mm/memory.c new file mode 100644 index 0000000000..d1f64fccd4 --- /dev/null +++ b/linux-2.6.8.1-xen-sparse/mm/memory.c @@ -0,0 +1,1822 @@ +/* + * linux/mm/memory.c + * + * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds + */ + +/* + * demand-loading started 01.12.91 - seems it is high on the list of + * things wanted, and it should be easy to implement. - Linus + */ + +/* + * Ok, demand-loading was easy, shared pages a little bit tricker. Shared + * pages started 02.12.91, seems to work. - Linus. + * + * Tested sharing by executing about 30 /bin/sh: under the old kernel it + * would have taken more than the 6M I have free, but it worked well as + * far as I could see. + * + * Also corrected some "invalidate()"s - I wasn't doing enough of them. + */ + +/* + * Real VM (paging to/from disk) started 18.12.91. Much more work and + * thought has to go into this. Oh, well.. + * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. + * Found it. Everything seems to work now. + * 20.12.91 - Ok, making the swap-device changeable like the root. + */ + +/* + * 05.04.94 - Multi-page memory management added for v1.1. + * Idea by Alex Bligh (alex@cconcepts.co.uk) + * + * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG + * (Gerhard.Wichert@pdb.siemens.de) + */ + +#include <linux/kernel_stat.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/mman.h> +#include <linux/swap.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/rmap.h> +#include <linux/module.h> +#include <linux/init.h> + +#include <asm/pgalloc.h> +#include <asm/uaccess.h> +#include <asm/tlb.h> +#include <asm/tlbflush.h> +#include <asm/pgtable.h> + +#include <linux/swapops.h> +#include <linux/elf.h> + +#ifndef CONFIG_DISCONTIGMEM +/* use the per-pgdat data instead for discontigmem - mbligh */ +unsigned long max_mapnr; +struct page *mem_map; + +EXPORT_SYMBOL(max_mapnr); +EXPORT_SYMBOL(mem_map); +#endif + +unsigned long num_physpages; +/* + * A number of key systems in x86 including ioremap() rely on the assumption + * that high_memory defines the upper bound on direct map memory, then end + * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and + * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL + * and ZONE_HIGHMEM. + */ +void * high_memory; +struct page *highmem_start_page; +unsigned long vmalloc_earlyreserve; + +EXPORT_SYMBOL(num_physpages); +EXPORT_SYMBOL(highmem_start_page); +EXPORT_SYMBOL(high_memory); +EXPORT_SYMBOL(vmalloc_earlyreserve); + +/* + * We special-case the C-O-W ZERO_PAGE, because it's such + * a common occurrence (no need to read the page to know + * that it's zero - better for the cache and memory subsystem). + */ +static inline void copy_cow_page(struct page * from, struct page * to, unsigned long address) +{ + if (from == ZERO_PAGE(address)) { + clear_user_highpage(to, address); + return; + } + copy_user_highpage(to, from, address); +} + +/* + * Note: this doesn't free the actual pages themselves. That + * has been handled earlier when unmapping all the memory regions. + */ +static inline void free_one_pmd(struct mmu_gather *tlb, pmd_t * dir) +{ + struct page *page; + + if (pmd_none(*dir)) + return; + if (unlikely(pmd_bad(*dir))) { + pmd_ERROR(*dir); + pmd_clear(dir); + return; + } + page = pmd_page(*dir); + pmd_clear(dir); + dec_page_state(nr_page_table_pages); + pte_free_tlb(tlb, page); +} + +static inline void free_one_pgd(struct mmu_gather *tlb, pgd_t * dir) +{ + int j; + pmd_t * pmd; + + if (pgd_none(*dir)) + return; + if (unlikely(pgd_bad(*dir))) { + pgd_ERROR(*dir); + pgd_clear(dir); + return; + } + pmd = pmd_offset(dir, 0); + pgd_clear(dir); + for (j = 0; j < PTRS_PER_PMD ; j++) + free_one_pmd(tlb, pmd+j); + pmd_free_tlb(tlb, pmd); +} + +/* + * This function clears all user-level page tables of a process - this + * is needed by execve(), so that old pages aren't in the way. + * + * Must be called with pagetable lock held. + */ +void clear_page_tables(struct mmu_gather *tlb, unsigned long first, int nr) +{ + pgd_t * page_dir = tlb->mm->pgd; + + page_dir += first; + do { + free_one_pgd(tlb, page_dir); + page_dir++; + } while (--nr); +} + +pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address) +{ + if (!pmd_present(*pmd)) { + struct page *new; + + spin_unlock(&mm->page_table_lock); + new = pte_alloc_one(mm, address); + spin_lock(&mm->page_table_lock); + if (!new) + return NULL; + + /* + * Because we dropped the lock, we should re-check the + * entry, as somebody else could have populated it.. + */ + if (pmd_present(*pmd)) { + pte_free(new); + goto out; + } + inc_page_state(nr_page_table_pages); + pmd_populate(mm, pmd, new); + } +out: + return pte_offset_map(pmd, address); +} + +pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address) +{ + if (!pmd_present(*pmd)) { + pte_t *new; + + spin_unlock(&mm->page_table_lock); + new = pte_alloc_one_kernel(mm, address); + spin_lock(&mm->page_table_lock); + if (!new) + return NULL; + + /* + * Because we dropped the lock, we should re-check the + * entry, as somebody else could have populated it.. + */ + if (pmd_present(*pmd)) { + pte_free_kernel(new); + goto out; + } + pmd_populate_kernel(mm, pmd, new); + } +out: + return pte_offset_kernel(pmd, address); +} +#define PTE_TABLE_MASK ((PTRS_PER_PTE-1) * sizeof(pte_t)) +#define PMD_TABLE_MASK ((PTRS_PER_PMD-1) * sizeof(pmd_t)) + +/* + * copy one vm_area from one task to the other. Assumes the page tables + * already present in the new task to be cleared in the whole range + * covered by this vma. + * + * 08Jan98 Merged into one routine from several inline routines to reduce + * variable count and make things faster. -jj + * + * dst->page_table_lock is held on entry and exit, + * but may be dropped within pmd_alloc() and pte_alloc_map(). + */ +int copy_page_range(struct mm_struct *dst, struct mm_struct *src, + struct vm_area_struct *vma) +{ + pgd_t * src_pgd, * dst_pgd; + unsigned long address = vma->vm_start; + unsigned long end = vma->vm_end; + unsigned long cow; + + if (is_vm_hugetlb_page(vma)) + return copy_hugetlb_page_range(dst, src, vma); + + cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; + src_pgd = pgd_offset(src, address)-1; + dst_pgd = pgd_offset(dst, address)-1; + + for (;;) { + pmd_t * src_pmd, * dst_pmd; + + src_pgd++; dst_pgd++; + + /* copy_pmd_range */ + + if (pgd_none(*src_pgd)) + goto skip_copy_pmd_range; + if (unlikely(pgd_bad(*src_pgd))) { + pgd_ERROR(*src_pgd); + pgd_clear(src_pgd); +skip_copy_pmd_range: address = (address + PGDIR_SIZE) & PGDIR_MASK; + if (!address || (address >= end)) + goto out; + continue; + } + + src_pmd = pmd_offset(src_pgd, address); + dst_pmd = pmd_alloc(dst, dst_pgd, address); + if (!dst_pmd) + goto nomem; + + do { + pte_t * src_pte, * dst_pte; + + /* copy_pte_range */ + + if (pmd_none(*src_pmd)) + goto skip_copy_pte_range; + if (unlikely(pmd_bad(*src_pmd))) { + pmd_ERROR(*src_pmd); + pmd_clear(src_pmd); +skip_copy_pte_range: + address = (address + PMD_SIZE) & PMD_MASK; + if (address >= end) + goto out; + goto cont_copy_pmd_range; + } + + dst_pte = pte_alloc_map(dst, dst_pmd, address); + if (!dst_pte) + goto nomem; + spin_lock(&src->page_table_lock); + src_pte = pte_offset_map_nested(src_pmd, address); + do { + pte_t pte = *src_pte; + struct page *page; + unsigned long pfn; + + /* copy_one_pte */ + + if (pte_none(pte)) + goto cont_copy_pte_range_noset; + /* pte contains position in swap, so copy. */ + if (!pte_present(pte)) { + if (!pte_file(pte)) + swap_duplicate(pte_to_swp_entry(pte)); + set_pte(dst_pte, pte); + goto cont_copy_pte_range_noset; + } + pfn = pte_pfn(pte); + /* the pte points outside of valid memory, the + * mapping is assumed to be good, meaningful + * and not mapped via rmap - duplicate the + * mapping as is. + */ + page = NULL; + if (pfn_valid(pfn)) + page = pfn_to_page(pfn); + + if (!page || PageReserved(page)) { + set_pte(dst_pte, pte); + goto cont_copy_pte_range_noset; + } + + /* + * If it's a COW mapping, write protect it both + * in the parent and the child + */ + if (cow) { + ptep_set_wrprotect(src_pte); + pte = *src_pte; + } + + /* + * If it's a shared mapping, mark it clean in + * the child + */ + if (vma->vm_flags & VM_SHARED) + pte = pte_mkclean(pte); + pte = pte_mkold(pte); + get_page(page); + dst->rss++; + set_pte(dst_pte, pte); + page_dup_rmap(page); +cont_copy_pte_range_noset: + address += PAGE_SIZE; + if (address >= end) { + pte_unmap_nested(src_pte); + pte_unmap(dst_pte); + goto out_unlock; + } + src_pte++; + dst_pte++; + } while ((unsigned long)src_pte & PTE_TABLE_MASK); + pte_unmap_nested(src_pte-1); + pte_unmap(dst_pte-1); + spin_unlock(&src->page_table_lock); + cond_resched_lock(&dst->page_table_lock); +cont_copy_pmd_range: + src_pmd++; + dst_pmd++; + } while ((unsigned long)src_pmd & PMD_TABLE_MASK); + } +out_unlock: + spin_unlock(&src->page_table_lock); +out: + return 0; +nomem: + return -ENOMEM; +} + +static void zap_pte_range(struct mmu_gather *tlb, + pmd_t *pmd, unsigned long address, + unsigned long size, struct zap_details *details) +{ + unsigned long offset; + pte_t *ptep; + + if (pmd_none(*pmd)) + return; + if (unlikely(pmd_bad(*pmd))) { + pmd_ERROR(*pmd); + pmd_clear(pmd); + return; + } + ptep = pte_offset_map(pmd, address); + offset = address & ~PMD_MASK; + if (offset + size > PMD_SIZE) + size = PMD_SIZE - offset; + size &= PAGE_MASK; + if (details && !details->check_mapping && !details->nonlinear_vma) + details = NULL; + for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) { + pte_t pte = *ptep; + if (pte_none(pte)) + continue; + if (pte_present(pte)) { + struct page *page = NULL; + unsigned long pfn = pte_pfn(pte); + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + if (PageReserved(page)) + page = NULL; + } + if (unlikely(details) && page) { + /* + * unmap_shared_mapping_pages() wants to + * invalidate cache without truncating: + * unmap shared but keep private pages. + */ + if (details->check_mapping && + details->check_mapping != page->mapping) + continue; + /* + * Each page->index must be checked when + * invalidating or truncating nonlinear. + */ + if (details->nonlinear_vma && + (page->index < details->first_index || + page->index > details->last_index)) + continue; + } + pte = ptep_get_and_clear(ptep); + tlb_remove_tlb_entry(tlb, ptep, address+offset); + if (unlikely(!page)) + continue; + if (unlikely(details) && details->nonlinear_vma + && linear_page_index(details->nonlinear_vma, + address+offset) != page->index) + set_pte(ptep, pgoff_to_pte(page->index)); + if (pte_dirty(pte)) + set_page_dirty(page); + if (pte_young(pte) && !PageAnon(page)) + mark_page_accessed(page); + tlb->freed++; + page_remove_rmap(page); + tlb_remove_page(tlb, page); + continue; + } + /* + * If details->check_mapping, we leave swap entries; + * if details->nonlinear_vma, we leave file entries. + */ + if (unlikely(details)) + continue; + if (!pte_file(pte)) + free_swap_and_cache(pte_to_swp_entry(pte)); + pte_clear(ptep); + } + pte_unmap(ptep-1); +} + +static void zap_pmd_range(struct mmu_gather *tlb, + pgd_t * dir, unsigned long address, + unsigned long size, struct zap_details *details) +{ + pmd_t * pmd; + unsigned long end; + + if (pgd_none(*dir)) + return; + if (unlikely(pgd_bad(*dir))) { + pgd_ERROR(*dir); + pgd_clear(dir); + return; + } + pmd = pmd_offset(dir, address); + end = address + size; + if (end > ((address + PGDIR_SIZE) & PGDIR_MASK)) + end = ((address + PGDIR_SIZE) & PGDIR_MASK); + do { + zap_pte_range(tlb, pmd, address, end - address, details); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address && (address < end)); +} + +static void unmap_page_range(struct mmu_gather *tlb, + struct vm_area_struct *vma, unsigned long address, + unsigned long end, struct zap_details *details) +{ + pgd_t * dir; + + BUG_ON(address >= end); + dir = pgd_offset(vma->vm_mm, address); + tlb_start_vma(tlb, vma); + do { + zap_pmd_range(tlb, dir, address, end - address, details); + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (address && (address < end)); + tlb_end_vma(tlb, vma); +} + +/* Dispose of an entire struct mmu_gather per rescheduling point */ +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) +#define ZAP_BLOCK_SIZE (FREE_PTE_NR * PAGE_SIZE) +#endif + +/* For UP, 256 pages at a time gives nice low latency */ +#if !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) +#define ZAP_BLOCK_SIZE (256 * PAGE_SIZE) +#endif + +/* No preempt: go for improved straight-line efficiency */ +#if !defined(CONFIG_PREEMPT) +#define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) +#endif + +/** + * unmap_vmas - unmap a range of memory covered by a list of vma's + * @tlbp: address of the caller's struct mmu_gather + * @mm: the controlling mm_struct + * @vma: the starting vma + * @start_addr: virtual address at which to start unmapping + * @end_addr: virtual address at which to end unmapping + * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here + * @details: details of nonlinear truncation or shared cache invalidation + * + * Returns the number of vma's which were covered by the unmapping. + * + * Unmap all pages in the vma list. Called under page_table_lock. + * + * We aim to not hold page_table_lock for too long (for scheduling latency + * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to + * return the ending mmu_gather to the caller. + * + * Only addresses between `start' and `end' will be unmapped. + * + * The VMA list must be sorted in ascending virtual address order. + * + * unmap_vmas() assumes that the caller will flush the whole unmapped address + * range after unmap_vmas() returns. So the only responsibility here is to + * ensure that any thus-far unmapped pages are flushed before unmap_vmas() + * drops the lock and schedules. + */ +int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, + struct vm_area_struct *vma, unsigned long start_addr, + unsigned long end_addr, unsigned long *nr_accounted, + struct zap_details *details) +{ + unsigned long zap_bytes = ZAP_BLOCK_SIZE; + unsigned long tlb_start = 0; /* For tlb_finish_mmu */ + int tlb_start_valid = 0; + int ret = 0; + int atomic = details && details->atomic; + + for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { + unsigned long start; + unsigned long end; + + start = max(vma->vm_start, start_addr); + if (start >= vma->vm_end) + continue; + end = min(vma->vm_end, end_addr); + if (end <= vma->vm_start) + continue; + + if (vma->vm_flags & VM_ACCOUNT) + *nr_accounted += (end - start) >> PAGE_SHIFT; + + ret++; + while (start != end) { + unsigned long block; + + if (!tlb_start_valid) { + tlb_start = start; + tlb_start_valid = 1; + } + + if (is_vm_hugetlb_page(vma)) { + block = end - start; + unmap_hugepage_range(vma, start, end); + } else { + block = min(zap_bytes, end - start); + unmap_page_range(*tlbp, vma, start, + start + block, details); + } + + start += block; + zap_bytes -= block; + if ((long)zap_bytes > 0) + continue; + if (!atomic && need_resched()) { + int fullmm = tlb_is_full_mm(*tlbp); + tlb_finish_mmu(*tlbp, tlb_start, start); + cond_resched_lock(&mm->page_table_lock); + *tlbp = tlb_gather_mmu(mm, fullmm); + tlb_start_valid = 0; + } + zap_bytes = ZAP_BLOCK_SIZE; + } + } + return ret; +} + +/** + * zap_page_range - remove user pages in a given range + * @vma: vm_area_struct holding the applicable pages + * @address: starting address of pages to zap + * @size: number of bytes to zap + * @details: details of nonlinear truncation or shared cache invalidation + */ +void zap_page_range(struct vm_area_struct *vma, unsigned long address, + unsigned long size, struct zap_details *details) +{ + struct mm_struct *mm = vma->vm_mm; + struct mmu_gather *tlb; + unsigned long end = address + size; + unsigned long nr_accounted = 0; + + if (is_vm_hugetlb_page(vma)) { + zap_hugepage_range(vma, address, size); + return; + } + + lru_add_drain(); + spin_lock(&mm->page_table_lock); + tlb = tlb_gather_mmu(mm, 0); + unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details); + tlb_finish_mmu(tlb, address, end); + spin_unlock(&mm->page_table_lock); +} + +/* + * Do a quick page-table lookup for a single page. + * mm->page_table_lock must be held. + */ +struct page * +follow_page(struct mm_struct *mm, unsigned long address, int write) +{ + pgd_t *pgd; + pmd_t *pmd; + pte_t *ptep, pte; + unsigned long pfn; + struct page *page; + + page = follow_huge_addr(mm, address, write); + if (! IS_ERR(page)) + return page; + + pgd = pgd_offset(mm, address); + if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) + goto out; + + pmd = pmd_offset(pgd, address); + if (pmd_none(*pmd)) + goto out; + if (pmd_huge(*pmd)) + return follow_huge_pmd(mm, address, pmd, write); + if (unlikely(pmd_bad(*pmd))) + goto out; + + ptep = pte_offset_map(pmd, address); + if (!ptep) + goto out; + + pte = *ptep; + pte_unmap(ptep); + if (pte_present(pte)) { + if (write && !pte_write(pte)) + goto out; + pfn = pte_pfn(pte); + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + if (write && !pte_dirty(pte) && !PageDirty(page)) + set_page_dirty(page); + mark_page_accessed(page); + return page; + } + } + +out: + return NULL; +} + +/* + * Given a physical address, is there a useful struct page pointing to + * it? This may become more complex in the future if we start dealing + * with IO-aperture pages for direct-IO. + */ + +static inline struct page *get_page_map(struct page *page) +{ + if (!pfn_valid(page_to_pfn(page))) + return NULL; + return page; +} + + +static inline int +untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, + unsigned long address) +{ + pgd_t *pgd; + pmd_t *pmd; + + /* Check if the vma is for an anonymous mapping. */ + if (vma->vm_ops && vma->vm_ops->nopage) + return 0; + + /* Check if page directory entry exists. */ + pgd = pgd_offset(mm, address); + if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) + return 1; + + /* Check if page middle directory entry exists. */ + pmd = pmd_offset(pgd, address); + if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) + return 1; + + /* There is a pte slot for 'address' in 'mm'. */ + return 0; +} + + +int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, int write, int force, + struct page **pages, struct vm_area_struct **vmas) +{ + int i; + unsigned int flags; + + /* + * Require read or write permissions. + * If 'force' is set, we only require the "MAY" flags. + */ + flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); + flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); + i = 0; + + do { + struct vm_area_struct * vma; + + vma = find_extend_vma(mm, start); + if (!vma && in_gate_area(tsk, start)) { + unsigned long pg = start & PAGE_MASK; + struct vm_area_struct *gate_vma = get_gate_vma(tsk); + pgd_t *pgd; + pmd_t *pmd; + pte_t *pte; + if (write) /* user gate pages are read-only */ + return i ? : -EFAULT; + pgd = pgd_offset_gate(mm, pg); + if (!pgd) + return i ? : -EFAULT; + pmd = pmd_offset(pgd, pg); + if (!pmd) + return i ? : -EFAULT; + pte = pte_offset_map(pmd, pg); + if (!pte) + return i ? : -EFAULT; + if (!pte_present(*pte)) { + pte_unmap(pte); + return i ? : -EFAULT; + } + if (pages) { + pages[i] = pte_page(*pte); + get_page(pages[i]); + } + pte_unmap(pte); + if (vmas) + vmas[i] = gate_vma; + i++; + start += PAGE_SIZE; + len--; + continue; + } + + if (!vma || (pages && (vma->vm_flags & VM_IO)) + || !(flags & vma->vm_flags)) + return i ? : -EFAULT; + + if (is_vm_hugetlb_page(vma)) { + i = follow_hugetlb_page(mm, vma, pages, vmas, + &start, &len, i); + continue; + } + spin_lock(&mm->page_table_lock); + do { + struct page *map; + int lookup_write = write; + while (!(map = follow_page(mm, start, lookup_write))) { + /* + * Shortcut for anonymous pages. We don't want + * to force the creation of pages tables for + * insanly big anonymously mapped areas that + * nobody touched so far. This is important + * for doing a core dump for these mappings. + */ + if (!lookup_write && + untouched_anonymous_page(mm,vma,start)) { + map = ZERO_PAGE(start); + break; + } + spin_unlock(&mm->page_table_lock); + switch (handle_mm_fault(mm,vma,start,write)) { + case VM_FAULT_MINOR: + tsk->min_flt++; + break; + case VM_FAULT_MAJOR: + tsk->maj_flt++; + break; + case VM_FAULT_SIGBUS: + return i ? i : -EFAULT; + case VM_FAULT_OOM: + return i ? i : -ENOMEM; + default: + BUG(); + } + /* + * Now that we have performed a write fault + * and surely no longer have a shared page we + * shouldn't write, we shouldn't ignore an + * unwritable page in the page table if + * we are forcing write access. + */ + lookup_write = write && !force; + spin_lock(&mm->page_table_lock); + } + if (pages) { + pages[i] = get_page_map(map); + if (!pages[i]) { + spin_unlock(&mm->page_table_lock); + while (i--) + page_cache_release(pages[i]); + i = -EFAULT; + goto out; + } + flush_dcache_page(pages[i]); + if (!PageReserved(pages[i])) + page_cache_get(pages[i]); + } + if (vmas) + vmas[i] = vma; + i++; + start += PAGE_SIZE; + len--; + } while(len && start < vma->vm_end); + spin_unlock(&mm->page_table_lock); + } while(len); +out: + return i; +} + +EXPORT_SYMBOL(get_user_pages); + +static void zeromap_pte_range(pte_t * pte, unsigned long address, + unsigned long size, pgprot_t prot) +{ + unsigned long end; + + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + do { + pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot)); + BUG_ON(!pte_none(*pte)); + set_pte(pte, zero_pte); + address += PAGE_SIZE; + pte++; + } while (address && (address < end)); +} + +static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, + unsigned long size, pgprot_t prot) +{ + unsigned long base, end; + + base = address & PGDIR_MASK; + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + do { + pte_t * pte = pte_alloc_map(mm, pmd, base + address); + if (!pte) + return -ENOMEM; + zeromap_pte_range(pte, base + address, end - address, prot); + pte_unmap(pte); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address && (address < end)); + return 0; +} + +int zeromap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, pgprot_t prot) +{ + int error = 0; + pgd_t * dir; + unsigned long beg = address; + unsigned long end = address + size; + struct mm_struct *mm = vma->vm_mm; + + dir = pgd_offset(mm, address); + flush_cache_range(vma, beg, end); + if (address >= end) + BUG(); + + spin_lock(&mm->page_table_lock); + do { + pmd_t *pmd = pmd_alloc(mm, dir, address); + error = -ENOMEM; + if (!pmd) + break; + error = zeromap_pmd_range(mm, pmd, address, end - address, prot); + if (error) + break; + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (address && (address < end)); + /* + * Why flush? zeromap_pte_range has a BUG_ON for !pte_none() + */ + flush_tlb_range(vma, beg, end); + spin_unlock(&mm->page_table_lock); + return error; +} + +/* + * maps a range of physical memory into the requested pages. the old + * mappings are removed. any references to nonexistent pages results + * in null mappings (currently treated as "copy-on-access") + */ +static inline void remap_pte_range(pte_t * pte, unsigned long address, unsigned long size, + unsigned long phys_addr, pgprot_t prot) +{ + unsigned long end; + unsigned long pfn; + + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + pfn = phys_addr >> PAGE_SHIFT; + do { + BUG_ON(!pte_none(*pte)); + if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn))) + set_pte(pte, pfn_pte(pfn, prot)); + address += PAGE_SIZE; + pfn++; + pte++; + } while (address && (address < end)); +} + +static inline int remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size, + unsigned long phys_addr, pgprot_t prot) +{ + unsigned long base, end; + + base = address & PGDIR_MASK; + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + phys_addr -= address; + do { + pte_t * pte = pte_alloc_map(mm, pmd, base + address); + if (!pte) + return -ENOMEM; + remap_pte_range(pte, base + address, end - address, address + phys_addr, prot); + pte_unmap(pte); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address && (address < end)); + return 0; +} + +/* Note: this is only safe if the mm semaphore is held when called. */ +int remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long phys_addr, unsigned long size, pgprot_t prot) +{ + int error = 0; + pgd_t * dir; + unsigned long beg = from; + unsigned long end = from + size; + struct mm_struct *mm = vma->vm_mm; + + phys_addr -= from; + dir = pgd_offset(mm, from); + flush_cache_range(vma, beg, end); + if (from >= end) + BUG(); + + spin_lock(&mm->page_table_lock); + do { + pmd_t *pmd = pmd_alloc(mm, dir, from); + error = -ENOMEM; + if (!pmd) + break; + error = remap_pmd_range(mm, pmd, from, end - from, phys_addr + from, prot); + if (error) + break; + from = (from + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (from && (from < end)); + /* + * Why flush? remap_pte_range has a BUG_ON for !pte_none() + */ + flush_tlb_range(vma, beg, end); + spin_unlock(&mm->page_table_lock); + return error; +} + +EXPORT_SYMBOL(remap_page_range); + +/* + * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when + * servicing faults for write access. In the normal case, do always want + * pte_mkwrite. But get_user_pages can cause write faults for mappings + * that do not have writing enabled, when used by access_process_vm. + */ +static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_WRITE)) + pte = pte_mkwrite(pte); + return pte; +} + +/* + * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock + */ +static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address, + pte_t *page_table) +{ + pte_t entry; + + flush_cache_page(vma, address); + entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)), + vma); + ptep_establish(vma, address, page_table, entry); + update_mmu_cache(vma, address, entry); +} + +/* + * This routine handles present pages, when users try to write + * to a shared page. It is done by copying the page to a new address + * and decrementing the shared-page counter for the old page. + * + * Goto-purists beware: the only reason for goto's here is that it results + * in better assembly code.. The "default" path will see no jumps at all. + * + * Note that this routine assumes that the protection checks have been + * done by the caller (the low-level page fault routine in most cases). + * Thus we can safely just mark it writable once we've done any necessary + * COW. + * + * We also mark the page dirty at this point even though the page will + * change only once the write actually happens. This avoids a few races, + * and potentially makes it more efficient. + * + * We hold the mm semaphore and the page_table_lock on entry and exit + * with the page_table_lock released. + */ +static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma, + unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte) +{ + struct page *old_page, *new_page; + unsigned long pfn = pte_pfn(pte); + pte_t entry; + + if (unlikely(!pfn_valid(pfn))) { + /* + * This should really halt the system so it can be debugged or + * at least the kernel stops what it's doing before it corrupts + * data, but for the moment just pretend this is OOM. + */ + pte_unmap(page_table); + printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n", + address); + spin_unlock(&mm->page_table_lock); + return VM_FAULT_OOM; + } + old_page = pfn_to_page(pfn); + + if (!TestSetPageLocked(old_page)) { + int reuse = can_share_swap_page(old_page); + unlock_page(old_page); + if (reuse) { + flush_cache_page(vma, address); + entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)), + vma); + ptep_set_access_flags(vma, address, page_table, entry, 1); + update_mmu_cache(vma, address, entry); + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + return VM_FAULT_MINOR; + } + } + pte_unmap(page_table); + + /* + * Ok, we need to copy. Oh, well.. + */ + if (!PageReserved(old_page)) + page_cache_get(old_page); + spin_unlock(&mm->page_table_lock); + + if (unlikely(anon_vma_prepare(vma))) + goto no_new_page; + new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); + if (!new_page) + goto no_new_page; + copy_cow_page(old_page,new_page,address); + + /* + * Re-check the pte - we dropped the lock + */ + spin_lock(&mm->page_table_lock); + page_table = pte_offset_map(pmd, address); + if (likely(pte_same(*page_table, pte))) { + if (PageReserved(old_page)) + ++mm->rss; + else + page_remove_rmap(old_page); + break_cow(vma, new_page, address, page_table); + lru_cache_add_active(new_page); + page_add_anon_rmap(new_page, vma, address); + + /* Free the old page.. */ + new_page = old_page; + } + pte_unmap(page_table); + page_cache_release(new_page); + page_cache_release(old_page); + spin_unlock(&mm->page_table_lock); + return VM_FAULT_MINOR; + +no_new_page: + page_cache_release(old_page); + return VM_FAULT_OOM; +} + +/* + * Helper function for unmap_mapping_range(). + */ +static inline void unmap_mapping_range_list(struct prio_tree_root *root, + struct zap_details *details) +{ + struct vm_area_struct *vma = NULL; + struct prio_tree_iter iter; + pgoff_t vba, vea, zba, zea; + + while ((vma = vma_prio_tree_next(vma, root, &iter, + details->first_index, details->last_index)) != NULL) { + vba = vma->vm_pgoff; + vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; + /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ + zba = details->first_index; + if (zba < vba) + zba = vba; + zea = details->last_index; + if (zea > vea) + zea = vea; + zap_page_range(vma, + ((zba - vba) << PAGE_SHIFT) + vma->vm_start, + (zea - zba + 1) << PAGE_SHIFT, details); + } +} + +/** + * unmap_mapping_range - unmap the portion of all mmaps + * in the specified address_space corresponding to the specified + * page range in the underlying file. + * @address_space: the address space containing mmaps to be unmapped. + * @holebegin: byte in first page to unmap, relative to the start of + * the underlying file. This will be rounded down to a PAGE_SIZE + * boundary. Note that this is different from vmtruncate(), which + * must keep the partial page. In contrast, we must get rid of + * partial pages. + * @holelen: size of prospective hole in bytes. This will be rounded + * up to a PAGE_SIZE boundary. A holelen of zero truncates to the + * end of the file. + * @even_cows: 1 when truncating a file, unmap even private COWed pages; + * but 0 when invalidating pagecache, don't throw away private data. + */ +void unmap_mapping_range(struct address_space *mapping, + loff_t const holebegin, loff_t const holelen, int even_cows) +{ + struct zap_details details; + pgoff_t hba = holebegin >> PAGE_SHIFT; + pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; + + /* Check for overflow. */ + if (sizeof(holelen) > sizeof(hlen)) { + long long holeend = + (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; + if (holeend & ~(long long)ULONG_MAX) + hlen = ULONG_MAX - hba + 1; + } + + details.check_mapping = even_cows? NULL: mapping; + details.nonlinear_vma = NULL; + details.first_index = hba; + details.last_index = hba + hlen - 1; + details.atomic = 1; /* A spinlock is held */ + if (details.last_index < details.first_index) + details.last_index = ULONG_MAX; + + spin_lock(&mapping->i_mmap_lock); + /* Protect against page fault */ + atomic_inc(&mapping->truncate_count); + + if (unlikely(!prio_tree_empty(&mapping->i_mmap))) + unmap_mapping_range_list(&mapping->i_mmap, &details); + + /* + * In nonlinear VMAs there is no correspondence between virtual address + * offset and file offset. So we must perform an exhaustive search + * across *all* the pages in each nonlinear VMA, not just the pages + * whose virtual address lies outside the file truncation point. + */ + if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) { + struct vm_area_struct *vma; + list_for_each_entry(vma, &mapping->i_mmap_nonlinear, + shared.vm_set.list) { + details.nonlinear_vma = vma; + zap_page_range(vma, vma->vm_start, + vma->vm_end - vma->vm_start, &details); + } + } + spin_unlock(&mapping->i_mmap_lock); +} +EXPORT_SYMBOL(unmap_mapping_range); + +/* + * Handle all mappings that got truncated by a "truncate()" + * system call. + * + * NOTE! We have to be ready to update the memory sharing + * between the file and the memory map for a potential last + * incomplete page. Ugly, but necessary. + */ +int vmtruncate(struct inode * inode, loff_t offset) +{ + struct address_space *mapping = inode->i_mapping; + unsigned long limit; + + if (inode->i_size < offset) + goto do_expand; + /* + * truncation of in-use swapfiles is disallowed - it would cause + * subsequent swapout to scribble on the now-freed blocks. + */ + if (IS_SWAPFILE(inode)) + goto out_busy; + i_size_write(inode, offset); + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + truncate_inode_pages(mapping, offset); + goto out_truncate; + +do_expand: + limit = current->rlim[RLIMIT_FSIZE].rlim_cur; + if (limit != RLIM_INFINITY && offset > limit) + goto out_sig; + if (offset > inode->i_sb->s_maxbytes) + goto out_big; + i_size_write(inode, offset); + +out_truncate: + if (inode->i_op && inode->i_op->truncate) + inode->i_op->truncate(inode); + return 0; +out_sig: + send_sig(SIGXFSZ, current, 0); +out_big: + return -EFBIG; +out_busy: + return -ETXTBSY; +} + +EXPORT_SYMBOL(vmtruncate); + +/* + * Primitive swap readahead code. We simply read an aligned block of + * (1 << page_cluster) entries in the swap area. This method is chosen + * because it doesn't cost us any seek time. We also make sure to queue + * the 'original' request together with the readahead ones... + * + * This has been extended to use the NUMA policies from the mm triggering + * the readahead. + * + * Caller must hold down_read on the vma->vm_mm if vma is not NULL. + */ +void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) +{ +#ifdef CONFIG_NUMA + struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; +#endif + int i, num; + struct page *new_page; + unsigned long offset; + + /* + * Get the number of handles we should do readahead io to. + */ + num = valid_swaphandles(entry, &offset); + for (i = 0; i < num; offset++, i++) { + /* Ok, do the async read-ahead now */ + new_page = read_swap_cache_async(swp_entry(swp_type(entry), + offset), vma, addr); + if (!new_page) + break; + page_cache_release(new_page); +#ifdef CONFIG_NUMA + /* + * Find the next applicable VMA for the NUMA policy. + */ + addr += PAGE_SIZE; + if (addr == 0) + vma = NULL; + if (vma) { + if (addr >= vma->vm_end) { + vma = next_vma; + next_vma = vma ? vma->vm_next : NULL; + } + if (vma && addr < vma->vm_start) + vma = NULL; + } else { + if (next_vma && addr >= next_vma->vm_start) { + vma = next_vma; + next_vma = vma->vm_next; + } + } +#endif + } + lru_add_drain(); /* Push any new pages onto the LRU now */ +} + +/* + * We hold the mm semaphore and the page_table_lock on entry and + * should release the pagetable lock on exit.. + */ +static int do_swap_page(struct mm_struct * mm, + struct vm_area_struct * vma, unsigned long address, + pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access) +{ + struct page *page; + swp_entry_t entry = pte_to_swp_entry(orig_pte); + pte_t pte; + int ret = VM_FAULT_MINOR; + + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + page = lookup_swap_cache(entry); + if (!page) { + swapin_readahead(entry, address, vma); + page = read_swap_cache_async(entry, vma, address); + if (!page) { + /* + * Back out if somebody else faulted in this pte while + * we released the page table lock. + */ + spin_lock(&mm->page_table_lock); + page_table = pte_offset_map(pmd, address); + if (likely(pte_same(*page_table, orig_pte))) + ret = VM_FAULT_OOM; + else + ret = VM_FAULT_MINOR; + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + goto out; + } + + /* Had to read the page from swap area: Major fault */ + ret = VM_FAULT_MAJOR; + inc_page_state(pgmajfault); + } + + mark_page_accessed(page); + lock_page(page); + + /* + * Back out if somebody else faulted in this pte while we + * released the page table lock. + */ + spin_lock(&mm->page_table_lock); + page_table = pte_offset_map(pmd, address); + if (unlikely(!pte_same(*page_table, orig_pte))) { + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + unlock_page(page); + page_cache_release(page); + ret = VM_FAULT_MINOR; + goto out; + } + + /* The page isn't present yet, go ahead with the fault. */ + + swap_free(entry); + if (vm_swap_full()) + remove_exclusive_swap_page(page); + + mm->rss++; + pte = mk_pte(page, vma->vm_page_prot); + if (write_access && can_share_swap_page(page)) { + pte = maybe_mkwrite(pte_mkdirty(pte), vma); + write_access = 0; + } + unlock_page(page); + + flush_icache_page(vma, page); + set_pte(page_table, pte); + page_add_anon_rmap(page, vma, address); + + if (write_access) { + if (do_wp_page(mm, vma, address, + page_table, pmd, pte) == VM_FAULT_OOM) + ret = VM_FAULT_OOM; + goto out; + } + + /* No need to invalidate - it was non-present before */ + update_mmu_cache(vma, address, pte); + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); +out: + return ret; +} + +/* + * We are called with the MM semaphore and page_table_lock + * spinlock held to protect against concurrent faults in + * multithreaded programs. + */ +static int +do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, + pte_t *page_table, pmd_t *pmd, int write_access, + unsigned long addr) +{ + pte_t entry; + struct page * page = ZERO_PAGE(addr); + + /* Read-only mapping of ZERO_PAGE. */ + entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot)); + + /* ..except if it's a write access */ + if (write_access) { + /* Allocate our own private page. */ + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + + if (unlikely(anon_vma_prepare(vma))) + goto no_mem; + page = alloc_page_vma(GFP_HIGHUSER, vma, addr); + if (!page) + goto no_mem; + clear_user_highpage(page, addr); + + spin_lock(&mm->page_table_lock); + page_table = pte_offset_map(pmd, addr); + + if (!pte_none(*page_table)) { + pte_unmap(page_table); + page_cache_release(page); + spin_unlock(&mm->page_table_lock); + goto out; + } + mm->rss++; + entry = maybe_mkwrite(pte_mkdirty(mk_pte(page, + vma->vm_page_prot)), + vma); + lru_cache_add_active(page); + mark_page_accessed(page); + page_add_anon_rmap(page, vma, addr); + } + + ptep_establish_new(vma, addr, page_table, entry); + pte_unmap(page_table); + + /* No need to invalidate - it was non-present before */ + update_mmu_cache(vma, addr, entry); + spin_unlock(&mm->page_table_lock); +out: + return VM_FAULT_MINOR; +no_mem: + return VM_FAULT_OOM; +} + +/* + * do_no_page() tries to create a new page mapping. It aggressively + * tries to share with existing pages, but makes a separate copy if + * the "write_access" parameter is true in order to avoid the next + * page fault. + * + * As this is called only for pages that do not currently exist, we + * do not need to flush old virtual caches or the TLB. + * + * This is called with the MM semaphore held and the page table + * spinlock held. Exit with the spinlock released. + */ +static int +do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd) +{ + struct page * new_page; + struct address_space *mapping = NULL; + pte_t entry; + int sequence = 0; + int ret = VM_FAULT_MINOR; + int anon = 0; + + if (!vma->vm_ops || !vma->vm_ops->nopage) + return do_anonymous_page(mm, vma, page_table, + pmd, write_access, address); + pte_unmap(page_table); + spin_unlock(&mm->page_table_lock); + + if (vma->vm_file) { + mapping = vma->vm_file->f_mapping; + sequence = atomic_read(&mapping->truncate_count); + } + smp_rmb(); /* Prevent CPU from reordering lock-free ->nopage() */ +retry: + new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); + + /* no page was available -- either SIGBUS or OOM */ + if (new_page == NOPAGE_SIGBUS) + return VM_FAULT_SIGBUS; + if (new_page == NOPAGE_OOM) + return VM_FAULT_OOM; + + /* + * Should we do an early C-O-W break? + */ + if (write_access && !(vma->vm_flags & VM_SHARED)) { + struct page *page; + + if (unlikely(anon_vma_prepare(vma))) + goto oom; + page = alloc_page_vma(GFP_HIGHUSER, vma, address); + if (!page) + goto oom; + copy_user_highpage(page, new_page, address); + page_cache_release(new_page); + new_page = page; + anon = 1; + } + + spin_lock(&mm->page_table_lock); + /* + * For a file-backed vma, someone could have truncated or otherwise + * invalidated this page. If unmap_mapping_range got called, + * retry getting the page. + */ + if (mapping && + (unlikely(sequence != atomic_read(&mapping->truncate_count)))) { + sequence = atomic_read(&mapping->truncate_count); + spin_unlock(&mm->page_table_lock); + page_cache_release(new_page); + goto retry; + } + page_table = pte_offset_map(pmd, address); + + /* + * This silly early PAGE_DIRTY setting removes a race + * due to the bad i386 page protection. But it's valid + * for other architectures too. + * + * Note that if write_access is true, we either now have + * an exclusive copy of the page, or this is a shared mapping, + * so we can make it writable and dirty to avoid having to + * handle that later. + */ + /* Only go through if we didn't race with anybody else... */ + if (pte_none(*page_table)) { + if (!PageReserved(new_page)) + ++mm->rss; + flush_icache_page(vma, new_page); + entry = mk_pte(new_page, vma->vm_page_prot); + if (write_access) + entry = maybe_mkwrite(pte_mkdirty(entry), vma); + ptep_establish_new(vma, address, page_table, entry); + if (anon) { + lru_cache_add_active(new_page); + page_add_anon_rmap(new_page, vma, address); + } else + page_add_file_rmap(new_page); + pte_unmap(page_table); + } else { + /* One of our sibling threads was faster, back out. */ + pte_unmap(page_table); + page_cache_release(new_page); + spin_unlock(&mm->page_table_lock); + goto out; + } + + /* no need to invalidate: a not-present page shouldn't be cached */ + update_mmu_cache(vma, address, entry); + spin_unlock(&mm->page_table_lock); +out: + return ret; +oom: + page_cache_release(new_page); + ret = VM_FAULT_OOM; + goto out; +} + +/* + * Fault of a previously existing named mapping. Repopulate the pte + * from the encoded file_pte if possible. This enables swappable + * nonlinear vmas. + */ +static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma, + unsigned long address, int write_access, pte_t *pte, pmd_t *pmd) +{ + unsigned long pgoff; + int err; + + BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage); + /* + * Fall back to the linear mapping if the fs does not support + * ->populate: + */ + if (!vma->vm_ops || !vma->vm_ops->populate || + (write_access && !(vma->vm_flags & VM_SHARED))) { + pte_clear(pte); + return do_no_page(mm, vma, address, write_access, pte, pmd); + } + + pgoff = pte_to_pgoff(*pte); + + pte_unmap(pte); + spin_unlock(&mm->page_table_lock); + + err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0); + if (err == -ENOMEM) + return VM_FAULT_OOM; + if (err) + return VM_FAULT_SIGBUS; + return VM_FAULT_MAJOR; +} + +/* + * These routines also need to handle stuff like marking pages dirty + * and/or accessed for architectures that don't do it in hardware (most + * RISC architectures). The early dirtying is also good on the i386. + * + * There is also a hook called "update_mmu_cache()" that architectures + * with external mmu caches can use to update those (ie the Sparc or + * PowerPC hashed page tables that act as extended TLBs). + * + * Note the "page_table_lock". It is to protect against kswapd removing + * pages from under us. Note that kswapd only ever _removes_ pages, never + * adds them. As such, once we have noticed that the page is not present, + * we can drop the lock early. + * + * The adding of pages is protected by the MM semaphore (which we hold), + * so we don't need to worry about a page being suddenly been added into + * our VM. + * + * We enter with the pagetable spinlock held, we are supposed to + * release it when done. + */ +static inline int handle_pte_fault(struct mm_struct *mm, + struct vm_area_struct * vma, unsigned long address, + int write_access, pte_t *pte, pmd_t *pmd) +{ + pte_t entry; + + entry = *pte; + if (!pte_present(entry)) { + /* + * If it truly wasn't present, we know that kswapd + * and the PTE updates will not touch it later. So + * drop the lock. + */ + if (pte_none(entry)) + return do_no_page(mm, vma, address, write_access, pte, pmd); + if (pte_file(entry)) + return do_file_page(mm, vma, address, write_access, pte, pmd); + return do_swap_page(mm, vma, address, pte, pmd, entry, write_access); + } + + if (write_access) { + if (!pte_write(entry)) + return do_wp_page(mm, vma, address, pte, pmd, entry); + + entry = pte_mkdirty(entry); + } + entry = pte_mkyoung(entry); + ptep_set_access_flags(vma, address, pte, entry, write_access); + update_mmu_cache(vma, address, entry); + pte_unmap(pte); + spin_unlock(&mm->page_table_lock); + return VM_FAULT_MINOR; +} + +/* + * By the time we get here, we already hold the mm semaphore + */ +int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma, + unsigned long address, int write_access) +{ + pgd_t *pgd; + pmd_t *pmd; + + __set_current_state(TASK_RUNNING); + pgd = pgd_offset(mm, address); + + inc_page_state(pgfault); + + if (is_vm_hugetlb_page(vma)) + return VM_FAULT_SIGBUS; /* mapping truncation does this. */ + + /* + * We need the page table lock to synchronize with kswapd + * and the SMP-safe atomic PTE updates. + */ + spin_lock(&mm->page_table_lock); + pmd = pmd_alloc(mm, pgd, address); + + if (pmd) { + pte_t * pte = pte_alloc_map(mm, pmd, address); + if (pte) + return handle_pte_fault(mm, vma, address, write_access, pte, pmd); + } + spin_unlock(&mm->page_table_lock); + return VM_FAULT_OOM; +} + +/* + * Allocate page middle directory. + * + * We've already handled the fast-path in-line, and we own the + * page table lock. + * + * On a two-level page table, this ends up actually being entirely + * optimized away. + */ +pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) +{ + pmd_t *new; + + spin_unlock(&mm->page_table_lock); + new = pmd_alloc_one(mm, address); + spin_lock(&mm->page_table_lock); + if (!new) + return NULL; + + /* + * Because we dropped the lock, we should re-check the + * entry, as somebody else could have populated it.. + */ + if (pgd_present(*pgd)) { + pmd_free(new); + goto out; + } + pgd_populate(mm, pgd, new); +out: + return pmd_offset(pgd, address); +} + +int make_pages_present(unsigned long addr, unsigned long end) +{ + int ret, len, write; + struct vm_area_struct * vma; + + vma = find_vma(current->mm, addr); + write = (vma->vm_flags & VM_WRITE) != 0; + if (addr >= end) + BUG(); + if (end > vma->vm_end) + BUG(); + len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; + ret = get_user_pages(current, current->mm, addr, + len, write, 0, NULL, NULL); + if (ret < 0) + return ret; + return ret == len ? 0 : -1; +} + +/* + * Map a vmalloc()-space virtual address to the physical page. + */ +struct page * vmalloc_to_page(void * vmalloc_addr) +{ + unsigned long addr = (unsigned long) vmalloc_addr; + struct page *page = NULL; + pgd_t *pgd = pgd_offset_k(addr); + pmd_t *pmd; + pte_t *ptep, pte; + + if (!pgd_none(*pgd)) { + pmd = pmd_offset(pgd, addr); + if (!pmd_none(*pmd)) { + preempt_disable(); + ptep = pte_offset_map(pmd, addr); + pte = *ptep; + if (pte_present(pte)) + page = pte_page(pte); + pte_unmap(ptep); + preempt_enable(); + } + } + return page; +} + +EXPORT_SYMBOL(vmalloc_to_page); + +#if !defined(CONFIG_ARCH_GATE_AREA) + +#if defined(AT_SYSINFO_EHDR) +struct vm_area_struct gate_vma; + +static int __init gate_vma_init(void) +{ + gate_vma.vm_mm = NULL; + gate_vma.vm_start = FIXADDR_USER_START; + gate_vma.vm_end = FIXADDR_USER_END; + gate_vma.vm_page_prot = PAGE_READONLY; + gate_vma.vm_flags = 0; + return 0; +} +__initcall(gate_vma_init); +#endif + +struct vm_area_struct *get_gate_vma(struct task_struct *tsk) +{ +#ifdef AT_SYSINFO_EHDR + return &gate_vma; +#else + return NULL; +#endif +} + +int in_gate_area(struct task_struct *task, unsigned long addr) +{ +#ifdef AT_SYSINFO_EHDR + if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) + return 1; +#endif + return 0; +} + +#endif |