linux-kernel - [PATCH] powerpc/603: Always fault when _PAGE

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Message-Id: <9821e731e3de6693b183eb173ce97c4c5b44b4cc.1604943942.git.christophe.leroy@csgroup.eu>
Date:   Mon,  9 Nov 2020 17:46:26 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     gregkh@...uxfoundation.org, stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc/603: Always fault when _PAGE_ACCESSED is not set

[That is backport of 11522448e641e8f1690c9db06e01985e8e19b401 to linux 5.9]

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: 84de6ab0e904 ("powerpc/603: don't handle PAGE_ACCESSED in TLB miss handlers.")
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/a44367744de54e2315b2f1a8cbbd7f88488072e0.1602342806.git.christophe.leroy@csgroup.eu
---
 arch/powerpc/kernel/head_32.S | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index a5a612deef66..898c2fe4ac67 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -472,11 +472,7 @@ InstructionTLBMiss:
 	cmplw	0,r1,r3
 #endif
 	mfspr	r2, SPRN_SPRG_PGDIR
-#ifdef CONFIG_SWAP
 	li	r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
-#else
-	li	r1,_PAGE_PRESENT | _PAGE_EXEC
-#endif
 #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
 	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
@@ -538,11 +534,7 @@ DataLoadTLBMiss:
 	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
-#ifdef CONFIG_SWAP
 	li	r1, _PAGE_PRESENT | _PAGE_ACCESSED
-#else
-	li	r1, _PAGE_PRESENT
-#endif
 	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
@@ -618,11 +610,7 @@ DataStoreTLBMiss:
 	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
-#ifdef CONFIG_SWAP
 	li	r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED
-#else
-	li	r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT
-#endif
 	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
-- 
2.25.0