linux-kernel - [PATCH 5.9 114/133] powerpc/40x: Always fault when _PAGE

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Message-Id: <20201109125036.171681591@linuxfoundation.org>
Date:   Mon,  9 Nov 2020 13:56:16 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 5.9 114/133] powerpc/40x: Always fault when _PAGE_ACCESSED is not set

From: Christophe Leroy <christophe.leroy@...roup.eu>

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

---
 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