[PATCH v10 16/20] x86/asm/entry: Create stack frames in thunk functions

From: Josh Poimboeuf
Date: Thu Aug 13 2015 - 23:14:35 EST

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>
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

/* this one pushes 9 elems, the next one would be %rIP */
pushq %rdi
@@ -62,6 +65,7 @@ restore:
popq %rdx
popq %rsi
popq %rdi

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