diff options
| author | venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> | 2008-12-18 11:41:28 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-12-18 13:30:15 -0800 |
| commit | e121e418441525b5636321fe03d16f0193ad218e (patch) | |
| tree | d9f54fef9c4f137c2e8327edbf3ba8110dfb968d | |
| parent | 3c8bb73ace6249bd089b70c941440441940e3365 (diff) | |
x86: PAT: add follow_pfnmp_pte routine to help tracking pfnmap pages - v3
Impact: New currently unused interface.
Add a generic interface to follow pfn in a pfnmap vma range. This is used by
one of the subsequent x86 PAT related patch to keep track of memory types
for vma regions across vma copy and free.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | include/linux/mm.h | 3 | ||||
| -rw-r--r-- | mm/memory.c | 43 |
2 files changed, 46 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 2be8d9b5e46..a25024ff9c1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1223,6 +1223,9 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address, #define FOLL_GET 0x04 /* do get_page on page */ #define FOLL_ANON 0x08 /* give ZERO_PAGE if no pgtable */ +int follow_pfnmap_pte(struct vm_area_struct *vma, + unsigned long address, pte_t *ret_ptep); + typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, diff --git a/mm/memory.c b/mm/memory.c index cef95c8c77f..8ca6bbf34ad 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1111,6 +1111,49 @@ no_page_table: return page; } +int follow_pfnmap_pte(struct vm_area_struct *vma, unsigned long address, + pte_t *ret_ptep) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep, pte; + spinlock_t *ptl; + struct page *page; + struct mm_struct *mm = vma->vm_mm; + + if (!is_pfn_mapping(vma)) + goto err; + + page = NULL; + pgd = pgd_offset(mm, address); + if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) + goto err; + + pud = pud_offset(pgd, address); + if (pud_none(*pud) || unlikely(pud_bad(*pud))) + goto err; + + pmd = pmd_offset(pud, address); + if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) + goto err; + + ptep = pte_offset_map_lock(mm, pmd, address, &ptl); + + pte = *ptep; + if (!pte_present(pte)) + goto err_unlock; + + *ret_ptep = pte; + pte_unmap_unlock(ptep, ptl); + return 0; + +err_unlock: + pte_unmap_unlock(ptep, ptl); +err: + return -EINVAL; +} + /* Can we do the FOLL_ANON optimization? */ static inline int use_zero_page(struct vm_area_struct *vma) { |