diff options
Diffstat (limited to 'fs/proc/task_mmu.c')
| -rw-r--r-- | fs/proc/task_mmu.c | 68 |
1 files changed, 47 insertions, 21 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 6dc0334815f7..9dfb5ff24209 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -527,13 +527,21 @@ struct pagemapread { char __user *out, *end; }; -#define PM_ENTRY_BYTES sizeof(u64) -#define PM_RESERVED_BITS 3 -#define PM_RESERVED_OFFSET (64 - PM_RESERVED_BITS) -#define PM_RESERVED_MASK (((1LL<<PM_RESERVED_BITS)-1) << PM_RESERVED_OFFSET) -#define PM_SPECIAL(nr) (((nr) << PM_RESERVED_OFFSET) & PM_RESERVED_MASK) -#define PM_NOT_PRESENT PM_SPECIAL(1LL) -#define PM_SWAP PM_SPECIAL(2LL) +#define PM_ENTRY_BYTES sizeof(u64) +#define PM_STATUS_BITS 3 +#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS) +#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET) +#define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK) +#define PM_PSHIFT_BITS 6 +#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS) +#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET) +#define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK) +#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1) +#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK) + +#define PM_PRESENT PM_STATUS(4LL) +#define PM_SWAP PM_STATUS(2LL) +#define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT) #define PM_END_OF_BUFFER 1 static int add_to_pagemap(unsigned long addr, u64 pfn, @@ -574,7 +582,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end, u64 swap_pte_to_pagemap_entry(pte_t pte) { swp_entry_t e = pte_to_swp_entry(pte); - return PM_SWAP | swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT); + return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT); } static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, @@ -588,9 +596,11 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, u64 pfn = PM_NOT_PRESENT; pte = pte_offset_map(pmd, addr); if (is_swap_pte(*pte)) - pfn = swap_pte_to_pagemap_entry(*pte); + pfn = PM_PFRAME(swap_pte_to_pagemap_entry(*pte)) + | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP; else if (pte_present(*pte)) - pfn = pte_pfn(*pte); + pfn = PM_PFRAME(pte_pfn(*pte)) + | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; /* unmap so we're not in atomic when we copy to userspace */ pte_unmap(pte); err = add_to_pagemap(addr, pfn, pm); @@ -611,12 +621,20 @@ static struct mm_walk pagemap_walk = { /* * /proc/pid/pagemap - an array mapping virtual pages to pfns * - * For each page in the address space, this file contains one 64-bit - * entry representing the corresponding physical page frame number - * (PFN) if the page is present. If there is a swap entry for the - * physical page, then an encoding of the swap file number and the - * page's offset into the swap file are returned. If no page is - * present at all, PM_NOT_PRESENT is returned. This allows determining + * For each page in the address space, this file contains one 64-bit entry + * consisting of the following: + * + * Bits 0-55 page frame number (PFN) if present + * Bits 0-4 swap type if swapped + * Bits 5-55 swap offset if swapped + * Bits 55-60 page shift (page size = 1<<page shift) + * Bit 61 reserved for future use + * Bit 62 page swapped + * Bit 63 page present + * + * If the page is not present but in swap, then the PFN contains an + * encoding of the swap file number and the page's offset into the + * swap. Unmapped pages return a null PFN. This allows determining * precisely which pages are mapped (or in swap) and comparing mapped * pages between processes. * @@ -640,17 +658,17 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, ret = -EACCES; if (!ptrace_may_attach(task)) - goto out; + goto out_task; ret = -EINVAL; /* file position must be aligned */ if (*ppos % PM_ENTRY_BYTES) - goto out; + goto out_task; ret = 0; mm = get_task_mm(task); if (!mm) - goto out; + goto out_task; ret = -ENOMEM; uaddr = (unsigned long)buf & PAGE_MASK; @@ -658,7 +676,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE; pages = kmalloc(pagecount * sizeof(struct page *), GFP_KERNEL); if (!pages) - goto out_task; + goto out_mm; down_read(¤t->mm->mmap_sem); ret = get_user_pages(current, current->mm, uaddr, pagecount, @@ -668,6 +686,12 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, if (ret < 0) goto out_free; + if (ret != pagecount) { + pagecount = ret; + ret = -EFAULT; + goto out_pages; + } + pm.out = buf; pm.end = buf + count; @@ -699,15 +723,17 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, ret = pm.out - buf; } +out_pages: for (; pagecount; pagecount--) { page = pages[pagecount-1]; if (!PageReserved(page)) SetPageDirty(page); page_cache_release(page); } - mmput(mm); out_free: kfree(pages); +out_mm: + mmput(mm); out_task: put_task_struct(task); out: |