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@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3f488a8e3bfc8ac7d4d3d350953e664e7182b044.1450442274.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h
index 793179cf8e21aa89636f869fc3a9e2fe0b4a29e0..cec213bd6eba0b0357537c591990dc243ef74216 100644 (file)
--- 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 */