Add support for selectively suppressing WARNING tracebacks to x86.
This requires adding the function triggering tracebacks to the __bug_table
object section.
To limit image size impact, the pointer to the function name is only added
to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
are enabled. Otherwise, the __func__ assembly parameter is replaced with a
(dummy) NULL parameter to avoid an image size increase due to unused
__func__ entries (this is necessary because __func__ is not a define but a
virtual variable).
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
arch/x86/include/asm/bug.h | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index a3ec87d198ac..8e45143fa676 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -21,6 +21,15 @@
# define __BUG_REL(val) ".long " __stringify(val) " - ."
#endif
+#if IS_ENABLED(CONFIG_KUNIT)
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR __BUG_REL(%c1)
+# define __BUG_FUNC __func__
+#else
+# define __BUG_FUNC_PTR
+# define __BUG_FUNC NULL
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUG_FLAGS(ins, flags, extra) \
@@ -29,12 +38,13 @@ do { \
".pushsection __bug_table,\"aw\"\n" \
"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
"\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
- "\t.word %c1" "\t# bug_entry::line\n" \
- "\t.word %c2" "\t# bug_entry::flags\n" \
- "\t.org 2b+%c3\n" \
+ "\t" __BUG_FUNC_PTR "\t# bug_entry::function\n" \
+ "\t.word %c2" "\t# bug_entry::line\n" \
+ "\t.word %c3" "\t# bug_entry::flags\n" \
+ "\t.org 2b+%c4\n" \
".popsection\n" \
extra \
- : : "i" (__FILE__), "i" (__LINE__), \
+ : : "i" (__FILE__), "i" (__BUG_FUNC), "i" (__LINE__),\
"i" (flags), \
"i" (sizeof(struct bug_entry))); \
} while (0)
@@ -80,7 +90,8 @@ do { \
do { \
__auto_type __flags = BUGFLAG_WARNING|(flags); \
instrumentation_begin(); \
- _BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE); \
+ if (!IS_SUPPRESSED_WARNING(__func__)) \
+ _BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE); \
instrumentation_end(); \
} while (0)
--
2.39.2
