* [PATCH] arm: fix inline asm in load_unaligned_zeropad()
@ 2021-04-01 16:55 ` Peter Collingbourne
0 siblings, 0 replies; 4+ messages in thread
From: Peter Collingbourne @ 2021-04-01 16:55 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon, Russell King
Cc: Peter Collingbourne, linux-arm-kernel, stable
The inline asm's addr operand is marked as input-only, however in
the case where an exception is taken it may be modified by the BIC
instruction on the exception path. Fix the problem by using a temporary
register as the destination register for the BIC instruction.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Cc: stable@vger.kernel.org
Link: https://linux-review.googlesource.com/id/I0f9ad1682821f874fb9b47e1279721943b2e5325
---
arch/arm/include/asm/word-at-a-time.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/word-at-a-time.h b/arch/arm/include/asm/word-at-a-time.h
index 352ab213520d..2e6d0b4349f4 100644
--- a/arch/arm/include/asm/word-at-a-time.h
+++ b/arch/arm/include/asm/word-at-a-time.h
@@ -66,7 +66,7 @@ static inline unsigned long find_zero(unsigned long mask)
*/
static inline unsigned long load_unaligned_zeropad(const void *addr)
{
- unsigned long ret, offset;
+ unsigned long ret, tmp;
/* Load word from unaligned pointer addr */
asm(
@@ -74,9 +74,9 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
"2:\n"
" .pushsection .text.fixup,\"ax\"\n"
" .align 2\n"
- "3: and %1, %2, #0x3\n"
- " bic %2, %2, #0x3\n"
- " ldr %0, [%2]\n"
+ "3: bic %1, %2, #0x3\n"
+ " ldr %0, [%1]\n"
+ " and %1, %2, #0x3\n"
" lsl %1, %1, #0x3\n"
#ifndef __ARMEB__
" lsr %0, %0, %1\n"
@@ -89,7 +89,7 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
" .align 3\n"
" .long 1b, 3b\n"
" .popsection"
- : "=&r" (ret), "=&r" (offset)
+ : "=&r" (ret), "=&r" (tmp)
: "r" (addr), "Qo" (*(unsigned long *)addr));
return ret;
--
2.31.0.291.g576ba9dcdaf-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] arm: fix inline asm in load_unaligned_zeropad()
@ 2021-04-01 16:55 ` Peter Collingbourne
0 siblings, 0 replies; 4+ messages in thread
From: Peter Collingbourne @ 2021-04-01 16:55 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon, Russell King
Cc: Peter Collingbourne, linux-arm-kernel, stable
The inline asm's addr operand is marked as input-only, however in
the case where an exception is taken it may be modified by the BIC
instruction on the exception path. Fix the problem by using a temporary
register as the destination register for the BIC instruction.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Cc: stable@vger.kernel.org
Link: https://linux-review.googlesource.com/id/I0f9ad1682821f874fb9b47e1279721943b2e5325
---
arch/arm/include/asm/word-at-a-time.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/word-at-a-time.h b/arch/arm/include/asm/word-at-a-time.h
index 352ab213520d..2e6d0b4349f4 100644
--- a/arch/arm/include/asm/word-at-a-time.h
+++ b/arch/arm/include/asm/word-at-a-time.h
@@ -66,7 +66,7 @@ static inline unsigned long find_zero(unsigned long mask)
*/
static inline unsigned long load_unaligned_zeropad(const void *addr)
{
- unsigned long ret, offset;
+ unsigned long ret, tmp;
/* Load word from unaligned pointer addr */
asm(
@@ -74,9 +74,9 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
"2:\n"
" .pushsection .text.fixup,\"ax\"\n"
" .align 2\n"
- "3: and %1, %2, #0x3\n"
- " bic %2, %2, #0x3\n"
- " ldr %0, [%2]\n"
+ "3: bic %1, %2, #0x3\n"
+ " ldr %0, [%1]\n"
+ " and %1, %2, #0x3\n"
" lsl %1, %1, #0x3\n"
#ifndef __ARMEB__
" lsr %0, %0, %1\n"
@@ -89,7 +89,7 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
" .align 3\n"
" .long 1b, 3b\n"
" .popsection"
- : "=&r" (ret), "=&r" (offset)
+ : "=&r" (ret), "=&r" (tmp)
: "r" (addr), "Qo" (*(unsigned long *)addr));
return ret;
--
2.31.0.291.g576ba9dcdaf-goog
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] arm: fix inline asm in load_unaligned_zeropad()
2021-04-01 16:55 ` Peter Collingbourne
@ 2021-04-01 17:16 ` Will Deacon
-1 siblings, 0 replies; 4+ messages in thread
From: Will Deacon @ 2021-04-01 17:16 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Catalin Marinas, Russell King, linux-arm-kernel, stable
On Thu, Apr 01, 2021 at 09:55:43AM -0700, Peter Collingbourne wrote:
> The inline asm's addr operand is marked as input-only, however in
> the case where an exception is taken it may be modified by the BIC
> instruction on the exception path. Fix the problem by using a temporary
> register as the destination register for the BIC instruction.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Cc: stable@vger.kernel.org
> Link: https://linux-review.googlesource.com/id/I0f9ad1682821f874fb9b47e1279721943b2e5325
> ---
> arch/arm/include/asm/word-at-a-time.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
Acked-by: Will Deacon <will@kernel.org>
Please can you put this into Russell's patch system?
Thanks,
Will
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] arm: fix inline asm in load_unaligned_zeropad()
@ 2021-04-01 17:16 ` Will Deacon
0 siblings, 0 replies; 4+ messages in thread
From: Will Deacon @ 2021-04-01 17:16 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Catalin Marinas, Russell King, linux-arm-kernel, stable
On Thu, Apr 01, 2021 at 09:55:43AM -0700, Peter Collingbourne wrote:
> The inline asm's addr operand is marked as input-only, however in
> the case where an exception is taken it may be modified by the BIC
> instruction on the exception path. Fix the problem by using a temporary
> register as the destination register for the BIC instruction.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Cc: stable@vger.kernel.org
> Link: https://linux-review.googlesource.com/id/I0f9ad1682821f874fb9b47e1279721943b2e5325
> ---
> arch/arm/include/asm/word-at-a-time.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
Acked-by: Will Deacon <will@kernel.org>
Please can you put this into Russell's patch system?
Thanks,
Will
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-04-01 16:55 [PATCH] arm: fix inline asm in load_unaligned_zeropad() Peter Collingbourne
2021-04-01 16:55 ` Peter Collingbourne
2021-04-01 17:16 ` Will Deacon
2021-04-01 17:16 ` Will Deacon
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