From 172420865b29233f9daeb7fb97da84224dcdbf40 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 14 Mar 2023 15:37:00 +0000 Subject: [PATCH] arm64: uaccess: remove unnecessary earlyclobber Currently the asm constraints for __get_mem_asm() mark the value register as an earlyclobber operand. This means that the compiler can't reuse the same register for both the address and value, even when the value is not subsequently used. There's no need for the value register to be marked as earlyclobber, as it's only written to after the address register is consumed, even when the access faults. Remove the unnecessary earlyclobber. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Robin Murphy Cc: Will Deacon Link: https://lore.kernel.org/r/20230314153700.787701-5-mark.rutland@arm.com Signed-off-by: Will Deacon --- arch/arm64/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 4ee5aa7..deaf4f8 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -237,7 +237,7 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) "1: " load " " reg "1, [%2]\n" \ "2:\n" \ _ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ - : "+r" (err), "=&r" (x) \ + : "+r" (err), "=r" (x) \ : "r" (addr)) #define __raw_get_mem(ldr, x, ptr, err, type) \ -- 2.7.4