From: Peter Collingbourne pcc@google.com

stable inclusion from linux-4.19.189 commit ab51a5ee10925b7c3f42767353ea61446b0247d6

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commit 185f2e5f51c2029efd9dd26cceb968a44fe053c6 upstream.

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/I84538c8a2307d567b4f45bb20b71545100... Link: https://lore.kernel.org/r/20210401165110.3952103-1-pcc@google.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/include/asm/word-at-a-time.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h index b0d708ff7f4e5..a2601c1ccf435 100644 --- a/arch/arm64/include/asm/word-at-a-time.h +++ b/arch/arm64/include/asm/word-at-a-time.h @@ -64,7 +64,7 @@ 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( @@ -72,9 +72,9 @@ static inline unsigned long load_unaligned_zeropad(const void *addr) "2:\n" " .pushsection .fixup,"ax"\n" " .align 2\n" - "3: and %1, %2, #0x7\n" - " bic %2, %2, #0x7\n" - " ldr %0, [%2]\n" + "3: bic %1, %2, #0x7\n" + " ldr %0, [%1]\n" + " and %1, %2, #0x7\n" " lsl %1, %1, #0x3\n" #ifndef __AARCH64EB__ " lsr %0, %0, %1\n" @@ -84,7 +84,7 @@ static inline unsigned long load_unaligned_zeropad(const void *addr) " b 2b\n" " .popsection\n" _ASM_EXTABLE(1b, 3b) - : "=&r" (ret), "=&r" (offset) + : "=&r" (ret), "=&r" (tmp) : "r" (addr), "Q" (*(unsigned long *)addr));

return ret;