[PATCH] powerpc/40x: Always fault when _PAGE_ACCESSED is not set

From: Christophe Leroy
Date: Sat Oct 10 2020 - 18:52:15 EST


The kernel expects pte_young() to work regardless of CONFIG_SWAP.

Make sure a minor fault is taken to set _PAGE_ACCESSED when it
is not already set, regardless of the selection of CONFIG_SWAP.

Fixes: 2c74e2586bb9 ("powerpc/40x: Rework 40x PTE access and TLB miss")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/kernel/head_40x.S | 8 --------
1 file changed, 8 deletions(-)

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 44c9018aed1b..a1ae00689e0f 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -284,11 +284,7 @@ _ENTRY(saved_ksp_limit)

rlwimi r11, r10, 22, 20, 29 /* Compute PTE address */
lwz r11, 0(r11) /* Get Linux PTE */
-#ifdef CONFIG_SWAP
li r9, _PAGE_PRESENT | _PAGE_ACCESSED
-#else
- li r9, _PAGE_PRESENT
-#endif
andc. r9, r9, r11 /* Check permission */
bne 5f

@@ -369,11 +365,7 @@ _ENTRY(saved_ksp_limit)

rlwimi r11, r10, 22, 20, 29 /* Compute PTE address */
lwz r11, 0(r11) /* Get Linux PTE */
-#ifdef CONFIG_SWAP
li r9, _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
-#else
- li r9, _PAGE_PRESENT | _PAGE_EXEC
-#endif
andc. r9, r9, r11 /* Check permission */
bne 5f

--
2.25.0