[PATCH] x86_64: reliable stack trace support

These are the generic bits needed to enable reliable stack traces based
on Dwarf2-like (.eh_frame) unwind information. Subsequent patches will
enable x86-64 and i386 to make use of this.

Thanks to Andi Kleen and Ingo Molnar, who pointed out several possibilities
for improvement.

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, 7 insertions, 0 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 3c5e4c2e517d..5c1ec1f84eab 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -32,6 +32,7 @@ extern const char linux_banner[];
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 #define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))
+#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
 
 #define KERN_EMERG      "<0>"   /* system is unusable                   */
 #define KERN_ALERT      "<1>"   /* action must be taken immediately     */
@@ -336,6 +337,12 @@ struct sysinfo {
 /* Force a compilation error if condition is true */
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 
+/* Force a compilation error if condition is true, but also produce a
+   result (of value 0 and type size_t), so the expression can be used
+   e.g. in a structure initializer (or where-ever else comma expressions
+   aren't permitted). */
+#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
+
 /* Trap pasters of __FUNCTION__ at compile-time */
 #define __FUNCTION__ (__func__)