[PATCH v15 11/25] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK

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From	Josh Poimboeuf <jpoimboe@redhat.com>
Newsgroups	linux.kernel
Subject	[PATCH v15 11/25] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK
Date	Fri, 18 Dec 2015 13:50:01 +0100
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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 c261402..6c7a4a1 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)
 {
@@ -750,15 +751,19 @@ 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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[PATCH v15 11/25] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100

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