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>

6 files changed, 12 insertions, 12 deletions

diff --git a/arch/arm64/include/asm/bug.h b/arch/arm64/include/asm/bug.h
index 561190d15881..a9be1072933c 100644
--- a/arch/arm64/include/asm/bug.h
+++ b/arch/arm64/include/asm/bug.h
@@ -55,7 +55,7 @@ _BUGVERBOSE_LOCATION(__FILE__, __LINE__)		\
 	unreachable();				\
 } while (0)
 
-#define __WARN_TAINT(taint) _BUG_FLAGS(BUGFLAG_TAINT(taint))
+#define __WARN_FLAGS(flags) _BUG_FLAGS(BUGFLAG_WARNING|(flags))
 
 #endif /* ! CONFIG_GENERIC_BUG */
 
diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h
index 62a33338549c..d2742273a685 100644
--- a/arch/parisc/include/asm/bug.h
+++ b/arch/parisc/include/asm/bug.h
@@ -46,7 +46,7 @@
 #endif
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
-#define __WARN_TAINT(taint)						\
+#define __WARN_FLAGS(flags)						\
 	do {								\
 		asm volatile("\n"					\
 			     "1:\t" PARISC_BUG_BREAK_ASM "\n"		\
@@ -56,11 +56,11 @@
 			     "\t.org 2b+%c3\n"				\
 			     "\t.popsection"				\
 			     : : "i" (__FILE__), "i" (__LINE__),	\
-			     "i" (BUGFLAG_TAINT(taint)), 		\
+			     "i" (BUGFLAG_WARNING|(flags)),		\
 			     "i" (sizeof(struct bug_entry)) );		\
 	} while(0)
 #else
-#define __WARN_TAINT(taint)						\
+#define __WARN_FLAGS(flags)						\
 	do {								\
 		asm volatile("\n"					\
 			     "1:\t" PARISC_BUG_BREAK_ASM "\n"		\
@@ -69,7 +69,7 @@
 			     "\t.short %c0\n"				\
 			     "\t.org 2b+%c1\n"				\
 			     "\t.popsection"				\
-			     : : "i" (BUGFLAG_TAINT(taint)),		\
+			     : : "i" (BUGFLAG_WARNING|(flags)),		\
 			     "i" (sizeof(struct bug_entry)) );		\
 	} while(0)
 #endif
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 3a39283333c3..f2c562a0a427 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -85,12 +85,12 @@
 	}							\
 } while (0)
 
-#define __WARN_TAINT(taint) do {				\
+#define __WARN_FLAGS(flags) do {				\
 	__asm__ __volatile__(					\
 		"1:	twi 31,0,0\n"				\
 		_EMIT_BUG_ENTRY					\
 		: : "i" (__FILE__), "i" (__LINE__),		\
-		  "i" (BUGFLAG_TAINT(taint)),			\
+		  "i" (BUGFLAG_WARNING|(flags)),		\
 		  "i" (sizeof(struct bug_entry)));		\
 } while (0)
 
diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index bf90d1fd97a5..1bbd9dbfe4e0 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -46,8 +46,8 @@
 	unreachable();					\
 } while (0)
 
-#define __WARN_TAINT(taint) do {			\
-	__EMIT_BUG(BUGFLAG_TAINT(taint));		\
+#define __WARN_FLAGS(flags) do {			\
+	__EMIT_BUG(BUGFLAG_WARNING|(flags));		\
 } while (0)
 
 #define WARN_ON(x) ({					\
diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index dcf278075429..1b77f068be2b 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -50,7 +50,7 @@ do {							\
 		   "i" (sizeof(struct bug_entry)));	\
 } while (0)
 
-#define __WARN_TAINT(taint)				\
+#define __WARN_FLAGS(flags)				\
 do {							\
 	__asm__ __volatile__ (				\
 		"1:\t.short %O0\n"			\
@@ -59,7 +59,7 @@ do {							\
 		 : "n" (TRAPA_BUG_OPCODE),		\
 		   "i" (__FILE__),			\
 		   "i" (__LINE__),			\
-		   "i" (BUGFLAG_TAINT(taint)),		\
+		   "i" (BUGFLAG_WARNING|(flags)),	\
 		   "i" (sizeof(struct bug_entry)));	\
 } while (0)
 
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index cecf559d0012..39e702d90cdb 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -76,7 +76,7 @@ do {								\
 	unreachable();						\
 } while (0)
 
-#define __WARN_TAINT(taint)	_BUG_FLAGS(ASM_UD0, BUGFLAG_TAINT(taint))
+#define __WARN_FLAGS(flags)	_BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags))
 
 #include <asm-generic/bug.h>