x86/kasan: Fix KASAN shadow region page tables

[uclinux-h8/linux.git] / arch / x86 / mm / kasan_init_64.c

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 4860906..0e4a05f 100644 (file)
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -11,7 +11,19 @@
 extern pgd_t early_level4_pgt[PTRS_PER_PGD];
 extern struct range pfn_mapped[E820_X_MAX];
 
-extern unsigned char kasan_zero_page[PAGE_SIZE];
+static pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss;
+static pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss;
+static pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss;
+
+/*
+ * This page used as early shadow. We don't use empty_zero_page
+ * at early stages, stack instrumentation could write some garbage
+ * to this page.
+ * Latter we reuse it as zero shadow for large ranges of memory
+ * that allowed to access, but not instrumented by kasan
+ * (vmalloc/vmemmap ...).
+ */
+static unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss;
 
 static int __init map_range(struct range *range)
 {
@@ -36,7 +48,7 @@ static void __init clear_pgds(unsigned long start,
                pgd_clear(pgd_offset_k(start));
 }
 
-void __init kasan_map_early_shadow(pgd_t *pgd)
+static void __init kasan_map_early_shadow(pgd_t *pgd)
 {
        int i;
        unsigned long start = KASAN_SHADOW_START;
@@ -166,6 +178,26 @@ static struct notifier_block kasan_die_notifier = {
 };
 #endif
 
+void __init kasan_early_init(void)
+{
+       int i;
+       pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL;
+       pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE;
+       pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE;
+
+       for (i = 0; i < PTRS_PER_PTE; i++)
+               kasan_zero_pte[i] = __pte(pte_val);
+
+       for (i = 0; i < PTRS_PER_PMD; i++)
+               kasan_zero_pmd[i] = __pmd(pmd_val);
+
+       for (i = 0; i < PTRS_PER_PUD; i++)
+               kasan_zero_pud[i] = __pud(pud_val);
+
+       kasan_map_early_shadow(early_level4_pgt);
+       kasan_map_early_shadow(init_level4_pgt);
+}
+
 void __init kasan_init(void)
 {
        int i;