[PATCH 19/26] x86/kasan: extend to support 5-level paging

[Kirill A. Shutemov]

This patch bring support for non-folded additional page table level.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Cc: Dmitry Vyukov <dvyu...@google.com
---
 arch/x86/mm/kasan_init_64.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 733f8ba6a01f..bcabc56e0dc4 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -50,8 +50,18 @@ static void __init kasan_map_early_shadow(pgd_t *pgd)
        unsigned long end = KASAN_SHADOW_END;
 
        for (i = pgd_index(start); start < end; i++) {
-               pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud)
-                               | _KERNPG_TABLE);
+               switch (CONFIG_PGTABLE_LEVELS) {
+               case 4:
+                       pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud) |
+                                       _KERNPG_TABLE);
+                       break;
+               case 5:
+                       pgd[i] = __pgd(__pa_nodebug(kasan_zero_p4d) |
+                                       _KERNPG_TABLE);
+                       break;
+               default:
+                       BUILD_BUG();
+               }
                start += PGDIR_SIZE;
        }
 }
@@ -79,6 +89,7 @@ void __init kasan_early_init(void)
        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;
+       p4dval_t p4d_val = __pa_nodebug(kasan_zero_pud) | _KERNPG_TABLE;
 
        for (i = 0; i < PTRS_PER_PTE; i++)
                kasan_zero_pte[i] = __pte(pte_val);
@@ -89,6 +100,9 @@ void __init kasan_early_init(void)
        for (i = 0; i < PTRS_PER_PUD; i++)
                kasan_zero_pud[i] = __pud(pud_val);
 
+       for (i = 0; CONFIG_PGTABLE_LEVELS >= 5 && i < PTRS_PER_P4D; i++)
+               kasan_zero_p4d[i] = __p4d(p4d_val);
+
        kasan_map_early_shadow(early_level4_pgt);
        kasan_map_early_shadow(init_level4_pgt);
 }
-- 
2.11.0