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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/pagewalk.h>#include <linux/debugfs.h>#include <linux/ptdump.h>#include <linux/kasan.h>#include "internal.h"
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)/* * This is an optimization for KASAN=y case. Since all kasan page tables * eventually point to the kasan_early_shadow_page we could call note_page() * right away without walking through lower level page tables. This saves * us dozens of seconds (minutes for 5-level config) while checking for * W+X mapping or reading kernel_page_tables debugfs file. */static inline int note_kasan_page_table(struct mm_walk *walk, unsigned long addr){ struct ptdump_state *st = walk->private;
st->note_page_pte(st, addr, kasan_early_shadow_pte[0]);
walk->action = ACTION_CONTINUE;
return 0;}#endif
static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, unsigned long next, struct mm_walk *walk){ struct ptdump_state *st = walk->private; pgd_t val = pgdp_get(pgd);
#if CONFIG_PGTABLE_LEVELS > 4 && \ (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d))) return note_kasan_page_table(walk, addr);#endif
if (st->effective_prot_pgd) st->effective_prot_pgd(st, val);
if (pgd_leaf(val)) { st->note_page_pgd(st, addr, val); walk->action = ACTION_CONTINUE; }
return 0;}
static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, unsigned long next, struct mm_walk *walk){ struct ptdump_state *st = walk->private; p4d_t val = p4dp_get(p4d);
#if CONFIG_PGTABLE_LEVELS > 3 && \ (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud))) return note_kasan_page_table(walk, addr);#endif
if (st->effective_prot_p4d) st->effective_prot_p4d(st, val);
if (p4d_leaf(val)) { st->note_page_p4d(st, addr, val); walk->action = ACTION_CONTINUE; }
return 0;}
static int ptdump_pud_entry(pud_t *pud, unsigned long addr, unsigned long next, struct mm_walk *walk){ struct ptdump_state *st = walk->private; pud_t val = pudp_get(pud);
#if CONFIG_PGTABLE_LEVELS > 2 && \ (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd))) return note_kasan_page_table(walk, addr);#endif
if (st->effective_prot_pud) st->effective_prot_pud(st, val);
if (pud_leaf(val)) { st->note_page_pud(st, addr, val); walk->action = ACTION_CONTINUE; }
return 0;}
static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long next, struct mm_walk *walk){ struct ptdump_state *st = walk->private; pmd_t val = pmdp_get(pmd);
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte))) return note_kasan_page_table(walk, addr);#endif
if (st->effective_prot_pmd) st->effective_prot_pmd(st, val); if (pmd_leaf(val)) { st->note_page_pmd(st, addr, val); walk->action = ACTION_CONTINUE; }
return 0;}
static int ptdump_pte_entry(pte_t *pte, unsigned long addr, unsigned long next, struct mm_walk *walk){ struct ptdump_state *st = walk->private; pte_t val = ptep_get(pte);
if (st->effective_prot_pte) st->effective_prot_pte(st, val);
st->note_page_pte(st, addr, val);
return 0;}
static int ptdump_hole(unsigned long addr, unsigned long next, int depth, struct mm_walk *walk){ struct ptdump_state *st = walk->private; pte_t pte_zero = {0}; pmd_t pmd_zero = {0}; pud_t pud_zero = {0}; p4d_t p4d_zero = {0}; pgd_t pgd_zero = {0};
switch (depth) { case 4: st->note_page_pte(st, addr, pte_zero); break; case 3: st->note_page_pmd(st, addr, pmd_zero); break; case 2: st->note_page_pud(st, addr, pud_zero); break; case 1: st->note_page_p4d(st, addr, p4d_zero); break; case 0: st->note_page_pgd(st, addr, pgd_zero); break; default: break; } return 0;}
static const struct mm_walk_ops ptdump_ops = { .pgd_entry = ptdump_pgd_entry, .p4d_entry = ptdump_p4d_entry, .pud_entry = ptdump_pud_entry, .pmd_entry = ptdump_pmd_entry, .pte_entry = ptdump_pte_entry, .pte_hole = ptdump_hole,};
void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd){ const struct ptdump_range *range = st->range;
get_online_mems(); mmap_write_lock(mm); while (range->start != range->end) { walk_page_range_debug(mm, range->start, range->end, &ptdump_ops, pgd, st); range++; } mmap_write_unlock(mm); put_online_mems();
/* Flush out the last page */ st->note_page_flush(st);}
static int check_wx_show(struct seq_file *m, void *v){ if (ptdump_check_wx()) seq_puts(m, "SUCCESS\n"); else seq_puts(m, "FAILED\n");
return 0;}
DEFINE_SHOW_ATTRIBUTE(check_wx);
static int ptdump_debugfs_init(void){ debugfs_create_file("check_wx_pages", 0400, NULL, NULL, &check_wx_fops);
return 0;}
device_initcall(ptdump_debugfs_init);