Merge branches 'pm-core', 'pm-qos', 'pm-domains' and 'pm-opp'

[linux.git] / arch / x86 / mm / dump_pagetables.c

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 8aa6bea1cd6cc467cd5d39dbcde7d625c009495c..58b5bee7ea27011419a0c81f5efeac3964a3ad71 100644 (file)
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -18,6 +18,7 @@
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 
+#include <asm/kasan.h>
 #include <asm/pgtable.h>
 
 /*
@@ -51,6 +52,10 @@ enum address_markers_idx {
        LOW_KERNEL_NR,
        VMALLOC_START_NR,
        VMEMMAP_START_NR,
+#ifdef CONFIG_KASAN
+       KASAN_SHADOW_START_NR,
+       KASAN_SHADOW_END_NR,
+#endif
 # ifdef CONFIG_X86_ESPFIX64
        ESPFIX_START_NR,
 # endif
@@ -76,6 +81,10 @@ static struct addr_marker address_markers[] = {
        { 0/* PAGE_OFFSET */,   "Low Kernel Mapping" },
        { 0/* VMALLOC_START */, "vmalloc() Area" },
        { 0/* VMEMMAP_START */, "Vmemmap" },
+#ifdef CONFIG_KASAN
+       { KASAN_SHADOW_START,   "KASAN shadow" },
+       { KASAN_SHADOW_END,     "KASAN shadow end" },
+#endif
 # ifdef CONFIG_X86_ESPFIX64
        { ESPFIX_BASE_ADDR,     "ESPfix Area", 16 },
 # endif
@@ -327,18 +336,31 @@ 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 +371,7 @@ 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++;
        }
 }