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

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@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b02ca2ed2d3676a096219b48c0f69ec982a75bcf.1602342801.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 5b282d9965a56822e7ea785fc1bb9017bd6d5dea..a3c3519b3f76a537a8bdd2429a30dc5736d0dbeb 100644 (file)
--- 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