[PATCH 5.9 114/133] powerpc/40x: Always fault when _PAGE_ACCESSED is not set

From: Greg Kroah-Hartman
Date: Mon Nov 09 2020 - 08:21:08 EST


From: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

commit 0540b0d2ce9073fd2a736d636218faa61c99e572 upstream.

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>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/b02ca2ed2d3676a096219b48c0f69ec982a75bcf.1602342801.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/powerpc/kernel/head_40x.S | 8 --------
1 file changed, 8 deletions(-)

--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -285,11 +285,7 @@ _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

@@ -370,11 +366,7 @@ _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