diff options
| -rw-r--r-- | include/linux/mm.h | 22 | ||||
| -rw-r--r-- | mm/Makefile | 2 | ||||
| -rw-r--r-- | mm/pagewalk.c | 131 |
3 files changed, 154 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index bcbe6979ff6..89d7c691b93 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -718,6 +718,28 @@ unsigned long unmap_vmas(struct mmu_gather **tlb, struct vm_area_struct *start_vma, unsigned long start_addr, unsigned long end_addr, unsigned long *nr_accounted, struct zap_details *); + +/** + * mm_walk - callbacks for walk_page_range + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry + * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry + * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry + * @pte_entry: if set, called for each non-empty PTE (4th-level) entry + * @pte_hole: if set, called for each hole at all levels + * + * (see walk_page_range for more details) + */ +struct mm_walk { + int (*pgd_entry)(pgd_t *, unsigned long, unsigned long, void *); + int (*pud_entry)(pud_t *, unsigned long, unsigned long, void *); + int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, void *); + int (*pte_entry)(pte_t *, unsigned long, unsigned long, void *); + int (*pte_hole)(unsigned long, unsigned long, void *); +}; + +int walk_page_range(const struct mm_struct *, unsigned long addr, + unsigned long end, const struct mm_walk *walk, + void *private); void free_pgd_range(struct mmu_gather **tlb, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling); void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma, diff --git a/mm/Makefile b/mm/Makefile index 5c0b0ea7572..07f12132f8e 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -5,7 +5,7 @@ mmu-y := nommu.o mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \ mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \ - vmalloc.o + vmalloc.o pagewalk.o obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \ page_alloc.o page-writeback.o pdflush.o \ diff --git a/mm/pagewalk.c b/mm/pagewalk.c new file mode 100644 index 00000000000..b4f27d22da9 --- /dev/null +++ b/mm/pagewalk.c @@ -0,0 +1,131 @@ +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/sched.h> + +static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, + const struct mm_walk *walk, void *private) +{ + pte_t *pte; + int err = 0; + + pte = pte_offset_map(pmd, addr); + do { + err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, private); + if (err) + break; + } while (pte++, addr += PAGE_SIZE, addr != end); + + pte_unmap(pte); + return err; +} + +static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, + const struct mm_walk *walk, void *private) +{ + pmd_t *pmd; + unsigned long next; + int err = 0; + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (pmd_none_or_clear_bad(pmd)) { + if (walk->pte_hole) + err = walk->pte_hole(addr, next, private); + if (err) + break; + continue; + } + if (walk->pmd_entry) + err = walk->pmd_entry(pmd, addr, next, private); + if (!err && walk->pte_entry) + err = walk_pte_range(pmd, addr, next, walk, private); + if (err) + break; + } while (pmd++, addr = next, addr != end); + + return err; +} + +static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, + const struct mm_walk *walk, void *private) +{ + pud_t *pud; + unsigned long next; + int err = 0; + + pud = pud_offset(pgd, addr); + do { + next = pud_addr_end(addr, end); + if (pud_none_or_clear_bad(pud)) { + if (walk->pte_hole) + err = walk->pte_hole(addr, next, private); + if (err) + break; + continue; + } + if (walk->pud_entry) + err = walk->pud_entry(pud, addr, next, private); + if (!err && (walk->pmd_entry || walk->pte_entry)) + err = walk_pmd_range(pud, addr, next, walk, private); + if (err) + break; + } while (pud++, addr = next, addr != end); + + return err; +} + +/** + * walk_page_range - walk a memory map's page tables with a callback + * @mm - memory map to walk + * @addr - starting address + * @end - ending address + * @walk - set of callbacks to invoke for each level of the tree + * @private - private data passed to the callback function + * + * Recursively walk the page table for the memory area in a VMA, + * calling supplied callbacks. Callbacks are called in-order (first + * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, + * etc.). If lower-level callbacks are omitted, walking depth is reduced. + * + * Each callback receives an entry pointer, the start and end of the + * associated range, and a caller-supplied private data pointer. + * + * No locks are taken, but the bottom level iterator will map PTE + * directories from highmem if necessary. + * + * If any callback returns a non-zero value, the walk is aborted and + * the return value is propagated back to the caller. Otherwise 0 is returned. + */ +int walk_page_range(const struct mm_struct *mm, + unsigned long addr, unsigned long end, + const struct mm_walk *walk, void *private) +{ + pgd_t *pgd; + unsigned long next; + int err = 0; + + if (addr >= end) + return err; + + pgd = pgd_offset(mm, addr); + do { + next = pgd_addr_end(addr, end); + if (pgd_none_or_clear_bad(pgd)) { + if (walk->pte_hole) + err = walk->pte_hole(addr, next, private); + if (err) + break; + continue; + } + if (walk->pgd_entry) + err = walk->pgd_entry(pgd, addr, next, private); + if (!err && + (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) + err = walk_pud_range(pgd, addr, next, walk, private); + if (err) + break; + } while (pgd++, addr = next, addr != end); + + return err; +} |