linux-kernel - [tip:x86/asm] x86/asm: Clean up frame pointer macros

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Date:	Tue, 19 Jan 2016 05:39:40 -0800
From:	tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	bernd@...rovitsch.priv.at, mingo@...nel.org, jslaby@...e.cz,
	bp@...en8.de, luto@...nel.org, chris.j.arges@...onical.com,
	dvlasenk@...hat.com, tglx@...utronix.de,
	linux-kernel@...r.kernel.org, hpa@...or.com, brgerst@...il.com,
	palves@...hat.com, peterz@...radead.org, acme@...nel.org,
	mmarek@...e.cz, torvalds@...ux-foundation.org, jpoimboe@...hat.com,
	luto@...capital.net, namhyung@...il.com
Subject: [tip:x86/asm] x86/asm: Clean up frame pointer macros

Commit-ID:  997963edd912a6d77d68b2bbc19f40ce8facabd7
Gitweb:     http://git.kernel.org/tip/997963edd912a6d77d68b2bbc19f40ce8facabd7
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Fri, 18 Dec 2015 06:39:18 -0600
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 19 Jan 2016 12:59:07 +0100

x86/asm: Clean up frame pointer macros

The asm macros for setting up and restoring the frame pointer
aren't currently being used.  However, they will be needed soon
to help asm functions to comply with stacktool.

Rename FRAME/ENDFRAME to FRAME_BEGIN/FRAME_END for more
symmetry.  Also make the code more readable and improve the
comments.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Bernd Petrovitsch <bernd@...rovitsch.priv.at>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Chris J Arges <chris.j.arges@...onical.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jiri Slaby <jslaby@...e.cz>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Michal Marek <mmarek@...e.cz>
Cc: Namhyung Kim <namhyung@...il.com>
Cc: Pedro Alves <palves@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/3f488a8e3bfc8ac7d4d3d350953e664e7182b044.1450442274.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/frame.h | 43 +++++++++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h
index 793179c..cec213b 100644
--- a/arch/x86/include/asm/frame.h
+++ b/arch/x86/include/asm/frame.h
@@ -1,23 +1,34 @@
+#ifndef _ASM_X86_FRAME_H
+#define _ASM_X86_FRAME_H
+
 #ifdef __ASSEMBLY__
 
 #include <asm/asm.h>
 
-/* The annotation hides the frame from the unwinder and makes it look
-   like a ordinary ebp save/restore. This avoids some special cases for
-   frame pointer later */
+/*
+ * These are stack frame creation macros.  They should be used by every
+ * callable non-leaf asm function to make kernel stack traces more reliable.
+ */
 #ifdef CONFIG_FRAME_POINTER
-	.macro FRAME
-	__ASM_SIZE(push,)	%__ASM_REG(bp)
-	__ASM_SIZE(mov)		%__ASM_REG(sp), %__ASM_REG(bp)
-	.endm
-	.macro ENDFRAME
-	__ASM_SIZE(pop,)	%__ASM_REG(bp)
-	.endm
-#else
-	.macro FRAME
-	.endm
-	.macro ENDFRAME
-	.endm
-#endif
+
+.macro FRAME_BEGIN
+	push %_ASM_BP
+	_ASM_MOV %_ASM_SP, %_ASM_BP
+.endm
+
+.macro FRAME_END
+	pop %_ASM_BP
+.endm
+
+#define FRAME_OFFSET __ASM_SEL(4, 8)
+
+#else /* !CONFIG_FRAME_POINTER */
+
+#define FRAME_BEGIN
+#define FRAME_END
+#define FRAME_OFFSET 0
+
+#endif /* CONFIG_FRAME_POINTER */
 
 #endif  /*  __ASSEMBLY__  */
+#endif /* _ASM_X86_FRAME_H */