[PATCHv4 17/33] x86/kasan: prepare clear_pgds() to switch to <asm-generic/pgtable-nop4d.h>

From: Kirill A. Shutemov
Date: Mon Mar 06 2017 - 08:58:00 EST


With folded p4d, pgd_clear() is nop. Change clear_pgds() to use
p4d_clear() instead.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
---
arch/x86/mm/kasan_init_64.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 8d63d7a104c3..733f8ba6a01f 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -32,8 +32,15 @@ static int __init map_range(struct range *range)
static void __init clear_pgds(unsigned long start,
unsigned long end)
{
- for (; start < end; start += PGDIR_SIZE)
- pgd_clear(pgd_offset_k(start));
+ pgd_t *pgd;
+
+ for (; start < end; start += PGDIR_SIZE) {
+ pgd = pgd_offset_k(start);
+ if (CONFIG_PGTABLE_LEVELS < 5)
+ p4d_clear(p4d_offset(pgd, start));
+ else
+ pgd_clear(pgd);
+ }
}

static void __init kasan_map_early_shadow(pgd_t *pgd)
--
2.11.0