Thread (2 messages) flat view 2 messages, 2 authors, 2020-07-16
STALE2217d

[PATCH 1/1] powerpc: Fix incorrect stw{, ux, u, x} instructions in __set_pte_at

From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: 2020-07-08 17:55:01
Also in: lkml, stable
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

The placeholder for instruction selection should use the second
argument's operand, which is %1, not %0. This could generate incorrect
assembly code if the instruction selection for argument %0 ever differs
from argument %1.

Fixes: 9bf2b5cdc5fe ("powerpc: Fixes for CONFIG_PTE_64BIT for SMP support")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christophe Leroy <redacted>
Cc: Kumar Gala <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: <redacted> # v2.6.28+
---
 arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
 arch/powerpc/include/asm/nohash/pgtable.h    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 224912432821..f1467b3c417a 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -529,7 +529,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 	__asm__ __volatile__("\
 		stw%U0%X0 %2,%0\n\
 		eieio\n\
-		stw%U0%X0 %L2,%1"
+		stw%U1%X1 %L2,%1"
 	: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
 	: "r" (pte) : "memory");
 
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 4b7c3472eab1..a00e4c1746d6 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -199,7 +199,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 		__asm__ __volatile__("\
 			stw%U0%X0 %2,%0\n\
 			eieio\n\
-			stw%U0%X0 %L2,%1"
+			stw%U1%X1 %L2,%1"
 		: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
 		: "r" (pte) : "memory");
 		return;
-- 
2.11.0
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