Commit e121e418441525b5636321fe03d16f0193ad218e
Committed by
H. Peter Anvin
H. Peter Anvin
1 parent
3c8bb73ace
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>
Showing 2 changed files with 46 additions and 0 deletions Side-by-side Diff
include/linux/mm.h
| ... | ... | @@ -1223,6 +1223,9 @@ |
| 1223 | 1223 | #define FOLL_GET 0x04 /* do get_page on page */ |
| 1224 | 1224 | #define FOLL_ANON 0x08 /* give ZERO_PAGE if no pgtable */ |
| 1225 | 1225 | |
| 1226 | +int follow_pfnmap_pte(struct vm_area_struct *vma, | |
| 1227 | + unsigned long address, pte_t *ret_ptep); | |
| 1228 | + | |
| 1226 | 1229 | typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, |
| 1227 | 1230 | void *data); |
| 1228 | 1231 | extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, |
mm/memory.c
| ... | ... | @@ -1111,6 +1111,49 @@ |
| 1111 | 1111 | return page; |
| 1112 | 1112 | } |
| 1113 | 1113 | |
| 1114 | +int follow_pfnmap_pte(struct vm_area_struct *vma, unsigned long address, | |
| 1115 | + pte_t *ret_ptep) | |
| 1116 | +{ | |
| 1117 | + pgd_t *pgd; | |
| 1118 | + pud_t *pud; | |
| 1119 | + pmd_t *pmd; | |
| 1120 | + pte_t *ptep, pte; | |
| 1121 | + spinlock_t *ptl; | |
| 1122 | + struct page *page; | |
| 1123 | + struct mm_struct *mm = vma->vm_mm; | |
| 1124 | + | |
| 1125 | + if (!is_pfn_mapping(vma)) | |
| 1126 | + goto err; | |
| 1127 | + | |
| 1128 | + page = NULL; | |
| 1129 | + pgd = pgd_offset(mm, address); | |
| 1130 | + if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
| 1131 | + goto err; | |
| 1132 | + | |
| 1133 | + pud = pud_offset(pgd, address); | |
| 1134 | + if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
| 1135 | + goto err; | |
| 1136 | + | |
| 1137 | + pmd = pmd_offset(pud, address); | |
| 1138 | + if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
| 1139 | + goto err; | |
| 1140 | + | |
| 1141 | + ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
| 1142 | + | |
| 1143 | + pte = *ptep; | |
| 1144 | + if (!pte_present(pte)) | |
| 1145 | + goto err_unlock; | |
| 1146 | + | |
| 1147 | + *ret_ptep = pte; | |
| 1148 | + pte_unmap_unlock(ptep, ptl); | |
| 1149 | + return 0; | |
| 1150 | + | |
| 1151 | +err_unlock: | |
| 1152 | + pte_unmap_unlock(ptep, ptl); | |
| 1153 | +err: | |
| 1154 | + return -EINVAL; | |
| 1155 | +} | |
| 1156 | + | |
| 1114 | 1157 | /* Can we do the FOLL_ANON optimization? */ |
| 1115 | 1158 | static inline int use_zero_page(struct vm_area_struct *vma) |
| 1116 | 1159 | { |