[PATCH] i386: reliable stack trace support i386 entry.S

To increase the usefulness of reliable stack unwinding, this adds CFI
unwind annotations to many low-level i386 routines.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/include/asm-i386/dwarf2.h b/include/asm-i386/dwarf2.h
new file mode 100644
index 000000000000..2280f6272f80
--- /dev/null
+++ b/include/asm-i386/dwarf2.h
@@ -0,0 +1,54 @@
+#ifndef _DWARF2_H
+#define _DWARF2_H
+
+#include <linux/config.h>
+
+#ifndef __ASSEMBLY__
+#warning "asm/dwarf2.h should be only included in pure assembly files"
+#endif
+
+/*
+   Macros for dwarf2 CFI unwind table entries.
+   See "as.info" for details on these pseudo ops. Unfortunately
+   they are only supported in very new binutils, so define them
+   away for older version.
+ */
+
+#ifdef CONFIG_UNWIND_INFO
+
+#define CFI_STARTPROC .cfi_startproc
+#define CFI_ENDPROC .cfi_endproc
+#define CFI_DEF_CFA .cfi_def_cfa
+#define CFI_DEF_CFA_REGISTER .cfi_def_cfa_register
+#define CFI_DEF_CFA_OFFSET .cfi_def_cfa_offset
+#define CFI_ADJUST_CFA_OFFSET .cfi_adjust_cfa_offset
+#define CFI_OFFSET .cfi_offset
+#define CFI_REL_OFFSET .cfi_rel_offset
+#define CFI_REGISTER .cfi_register
+#define CFI_RESTORE .cfi_restore
+#define CFI_REMEMBER_STATE .cfi_remember_state
+#define CFI_RESTORE_STATE .cfi_restore_state
+
+#else
+
+/* Due to the structure of pre-exisiting code, don't use assembler line
+   comment character # to ignore the arguments. Instead, use a dummy macro. */
+.macro ignore a=0, b=0, c=0, d=0
+.endm
+
+#define CFI_STARTPROC   ignore
+#define CFI_ENDPROC     ignore
+#define CFI_DEF_CFA     ignore
+#define CFI_DEF_CFA_REGISTER    ignore
+#define CFI_DEF_CFA_OFFSET      ignore
+#define CFI_ADJUST_CFA_OFFSET   ignore
+#define CFI_OFFSET      ignore
+#define CFI_REL_OFFSET  ignore
+#define CFI_REGISTER    ignore
+#define CFI_RESTORE     ignore
+#define CFI_REMEMBER_STATE ignore
+#define CFI_RESTORE_STATE ignore
+
+#endif
+
+#endif