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Subject[PATCH v12 09/21] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK
Date
A function created with the PV_CALLEE_SAVE_REGS_THUNK macro doesn't set
up a new stack frame before the call instruction, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace. Also, the thunk functions aren't annotated as ELF
callable functions.

Create a stack frame when CONFIG_FRAME_POINTER is enabled and add the
ELF function type.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
---
arch/x86/include/asm/paravirt.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 10d0596..23a382b 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -13,6 +13,7 @@
#include <linux/bug.h>
#include <linux/types.h>
#include <linux/cpumask.h>
+#include <asm/frame.h>

static inline int paravirt_enabled(void)
{
@@ -776,15 +777,19 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock,
* call. The return value in rax/eax will not be saved, even for void
* functions.
*/
+#define PV_THUNK_NAME(func) "__raw_callee_save_" #func
#define PV_CALLEE_SAVE_REGS_THUNK(func) \
extern typeof(func) __raw_callee_save_##func; \
\
asm(".pushsection .text;" \
- ".globl __raw_callee_save_" #func " ; " \
- "__raw_callee_save_" #func ": " \
+ ".globl " PV_THUNK_NAME(func) ";" \
+ ".type " PV_THUNK_NAME(func) ", @function;" \
+ PV_THUNK_NAME(func) ":" \
+ FRAME_BEGIN \
PV_SAVE_ALL_CALLER_REGS \
"call " #func ";" \
PV_RESTORE_ALL_CALLER_REGS \
+ FRAME_END \
"ret;" \
".popsection")

--
2.4.3


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