debug: Add _ONCE() logic to report_bug()
Josh suggested moving the _ONCE logic inside the trap handler, using a
bit in the bug_entry::flags field, avoiding the need for the extra
variable.
Sadly this only works for WARN_ON_ONCE(), since the others have
printk() statements prior to triggering the trap.
Still, this saves a fair amount of text and some data:
text data filename
10682460 4530992 defconfig-build/vmlinux.orig
10665111 4530096 defconfig-build/vmlinux.patched
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 6f96247..5fe9f39 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -5,6 +5,8 @@
#ifdef CONFIG_GENERIC_BUG
#define BUGFLAG_WARNING (1 << 0)
+#define BUGFLAG_ONCE (1 << 1)
+#define BUGFLAG_DONE (1 << 2)
#define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8))
#define BUG_GET_TAINT(bug) ((bug)->flags >> 8)
#endif
@@ -55,6 +57,18 @@ struct bug_entry {
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
#endif
+#ifdef __WARN_FLAGS
+#define __WARN_TAINT(taint) __WARN_FLAGS(BUGFLAG_TAINT(taint))
+#define __WARN_ONCE_TAINT(taint) __WARN_FLAGS(BUGFLAG_ONCE|BUGFLAG_TAINT(taint))
+
+#define WARN_ON_ONCE(condition) ({ \
+ int __ret_warn_on = !!(condition); \
+ if (unlikely(__ret_warn_on)) \
+ __WARN_ONCE_TAINT(TAINT_WARN); \
+ unlikely(__ret_warn_on); \
+})
+#endif
+
/*
* WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
* significant issues that need prompt attention if they should ever
@@ -97,7 +111,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
#endif
#ifndef WARN
-#define WARN(condition, format...) ({ \
+#define WARN(condition, format...) ({ \
int __ret_warn_on = !!(condition); \
if (unlikely(__ret_warn_on)) \
__WARN_printf(format); \
@@ -112,6 +126,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
unlikely(__ret_warn_on); \
})
+#ifndef WARN_ON_ONCE
#define WARN_ON_ONCE(condition) ({ \
static bool __section(.data.unlikely) __warned; \
int __ret_warn_once = !!(condition); \
@@ -122,6 +137,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
} \
unlikely(__ret_warn_once); \
})
+#endif
#define WARN_ONCE(condition, format...) ({ \
static bool __section(.data.unlikely) __warned; \
