Thread (47 messages) 47 messages, 8 authors, 2017-04-05

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

From: Dmitry Vyukov <dvyukov@google.com>
Date: 2017-03-13 07:26:13
Also in: linux-mm, lkml

On Mon, Mar 13, 2017 at 6:50 AM, Kirill A. Shutemov
[off-list ref] wrote:
This patch bring support for non-folded additional page table level.

Signed-off-by: Kirill A. Shutemov <redacted>
Cc: Dmitry Vyukov <dvyukov@google.com
+Andrey Ryabinin
quoted hunk ↗ jump to hunk
---
 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
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