[PATCH 16/33] x86/asm/entry: Create stack frames in thunk functions

[Josh Poimboeuf]

Thunk functions are callable non-leaf functions that don't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces.  Also they
aren't annotated as ELF callable functions which can confuse tooling.

Create stack frames for them when CONFIG_FRAME_POINTER is enabled and
add the ELF function type.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
---
 arch/x86/entry/thunk_64.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index efb2b93..98df1fa 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -8,11 +8,14 @@
 #include <linux/linkage.h>
 #include "calling.h"
 #include <asm/asm.h>
+#include <asm/frame.h>
 
 	/* rdi:	arg1 ... normal C conventions. rax is saved/restored. */
 	.macro THUNK name, func, put_ret_addr_in_rdi=0
 	.globl \name
+	.type \name, @function
 \name:
+	FRAME_BEGIN
 
 	/* this one pushes 9 elems, the next one would be %rIP */
 	pushq %rdi
@@ -62,6 +65,7 @@ restore:
 	popq %rdx
 	popq %rsi
 	popq %rdi
+	FRAME_END
 	ret
 	_ASM_NOKPROBE(restore)
 #endif
-- 
2.4.3