diff options
Diffstat (limited to 'arch/x86/mm/dump_pagetables.c')
| -rw-r--r-- | arch/x86/mm/dump_pagetables.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 8aa6bea1cd6c..08135341798c 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -327,18 +327,31 @@ static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr, #if PTRS_PER_PUD > 1 +/* + * This is an optimization for CONFIG_DEBUG_WX=y + CONFIG_KASAN=y + * KASAN fills page tables with the same values. Since there is no + * point in checking page table more than once we just skip repeated + * entries. This saves us dozens of seconds during boot. + */ +static bool pud_already_checked(pud_t *prev_pud, pud_t *pud, bool checkwx) +{ + return checkwx && prev_pud && (pud_val(*prev_pud) == pud_val(*pud)); +} + static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, unsigned long P) { int i; pud_t *start; pgprotval_t prot; + pud_t *prev_pud = NULL; start = (pud_t *) pgd_page_vaddr(addr); for (i = 0; i < PTRS_PER_PUD; i++) { st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT); - if (!pud_none(*start)) { + if (!pud_none(*start) && + !pud_already_checked(prev_pud, start, st->check_wx)) { if (pud_large(*start) || !pud_present(*start)) { prot = pud_flags(*start); note_page(m, st, __pgprot(prot), 2); @@ -349,6 +362,7 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, } else note_page(m, st, __pgprot(0), 2); + prev_pud = start; start++; } } |