[PATCH 1/3] x86/uaccess: Add stack frame output operand in get_user inline asm
From: Chris J Arges
Date: Thu Sep 17 2015 - 18:14:48 EST
Numerous 'call without frame pointer save/setup' warnings are introduced by
stacktool because of functions using the get_user macro. Bad stack traces could
occur due to lack of or misplacement of stack frame setup code.
This patch forces a stack frame to be created before the inline asm code if
CONFIG_FRAME_POINTER is enabled by listing the stack pointer as an output
operand for the get_user inline assembly statement.
Signed-off-by: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
---
arch/x86/include/asm/uaccess.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index a8df874..55b8db5 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -176,10 +176,11 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
({ \
int __ret_gu; \
register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
+ register void *__sp asm(_ASM_SP); \
__chk_user_ptr(ptr); \
might_fault(); \
- asm volatile("call __get_user_%P3" \
- : "=a" (__ret_gu), "=r" (__val_gu) \
+ asm volatile("call __get_user_%P4" \
+ : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \
: "0" (ptr), "i" (sizeof(*(ptr)))); \
(x) = (__force __typeof__(*(ptr))) __val_gu; \
__ret_gu; \
--
1.9.1
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