x86 stack is expected to be 16-byte aligned to allow for instructions
like movaps that involve xmm operands to directly use the stack.
However the 16-byte alignment is what's expected at startup time.
All later functions will have the stack misaligned by a pointer size's
worth because call pushes the return address to the call stack.
Add the missing (mis)alignment. This fixes a segmentation fault observed
using initjmp on x86_64.
Signed-off-by: Ahmad Fatoum <a.fat...@pengutronix.de>
---
arch/x86/lib/setjmp_32.S | 4 +++-
arch/x86/lib/setjmp_64.S | 2 ++
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/lib/setjmp_32.S b/arch/x86/lib/setjmp_32.S
index 38dcb68c1b59..30db5f989af6 100644
--- a/arch/x86/lib/setjmp_32.S
+++ b/arch/x86/lib/setjmp_32.S
@@ -8,6 +8,7 @@
#define _REGPARM
#include <linux/linkage.h>
+#include <asm-generic/pointer.h>
.text
.align 8
@@ -53,7 +54,8 @@ ENDPROC(longjmp)
ENTRY(initjmp)
movl %edx, 20(%eax) /* Return address */
- movl %ecx, 4(%eax) /* Post-return %esp! */
+ sub $ASM_SZPTR, %ecx /* ESP - 4 has to be 16-byte aligned on entry */
+ movl %ecx, 4(%eax) /* Stack top */
xorl %eax, %eax /* Return value */
ret
diff --git a/arch/x86/lib/setjmp_64.S b/arch/x86/lib/setjmp_64.S
index 28ea576cd22e..d5cf99a1557f 100644
--- a/arch/x86/lib/setjmp_64.S
+++ b/arch/x86/lib/setjmp_64.S
@@ -6,6 +6,7 @@
*/
#include <linux/linkage.h>
+#include <asm-generic/pointer.h>
.text
.align 8
@@ -53,6 +54,7 @@ ENDPROC(longjmp)
ENTRY(initjmp)
movq %rsi, (%rdi) /* Return address */
+ sub $ASM_SZPTR, %rdx /* RSP - 8 has to be 16-byte aligned on
entry */
movq %rdx, 8(%rdi) /* Stack top */
xorq %rax, %rax
ret
--
2.39.2
