[RFC 4/8] bug: Allow architectures to provide __WARN_printf()

Peter Zijlstra
2025-06-02T14:50:43Z

Instead of providing __WARN_FLAGS(), allow an architecture to provide
__WARN_printf(), which allows for optimizing WARN(), rather than
WARN_ON().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/asm-generic/bug.h | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -94,14 +94,7 @@ void warn_slowpath_fmt(const char *file,
const char *fmt, ...);
extern __printf(1, 2) void __warn_printk(const char *fmt, ...);

-#ifndef __WARN_FLAGS
-#define __WARN() __WARN_printf(TAINT_WARN, NULL)
-#define __WARN_printf(taint, arg...) do { \
- instrumentation_begin(); \
- warn_slowpath_fmt(__FILE__, __LINE__, taint, arg); \
- instrumentation_end(); \
- } while (0)
-#else
+#if defined(__WARN_FLAGS) && !defined(__WARN_printf)
#define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
#define __WARN_printf(taint, arg...) do { \
instrumentation_begin(); \
@@ -118,6 +111,18 @@ extern __printf(1, 2) void __warn_printk
})
#endif

+#ifndef __WARN_printf
+#define __WARN_printf(taint, arg...) do { \
+ instrumentation_begin(); \
+ warn_slowpath_fmt(__FILE__, __LINE__, taint, arg); \
+ instrumentation_end(); \
+ } while (0)
+#endif
+
+#ifndef __WARN
+#define __WARN() __WARN_printf(TAINT_WARN, NULL)
+#endif
+
/* used internally by panic.c */

#ifndef WARN_ON