[PATCH 12/14] sh: Add support for suppressing warning backtraces

Guenter Roeck
2024-03-12T17:03:42Z

Add name of functions triggering warning backtraces to the __bug_table
object section to enable support for suppressing WARNING backtraces.

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@roeck-us.net>
---
arch/sh/include/asm/bug.h | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index 05a485c4fabc..cadc335eb759 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -24,21 +24,36 @@
* The offending file and line are encoded in the __bug_table section.
*/
#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#if IS_ENABLED(CONFIG_KUNIT)
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR "\t.long %O2\n"
+#else
+# define __BUG_FUNC_PTR
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
#define _EMIT_BUG_ENTRY \
"\t.pushsection __bug_table,\"aw\"\n" \
"2:\t.long 1b, %O1\n" \
- "\t.short %O2, %O3\n" \
- "\t.org 2b+%O4\n" \
+ __BUG_FUNC_PTR \
+ "\t.short %O3, %O4\n" \
+ "\t.org 2b+%O5\n" \
"\t.popsection\n"
#else
#define _EMIT_BUG_ENTRY \
"\t.pushsection __bug_table,\"aw\"\n" \
"2:\t.long 1b\n" \
- "\t.short %O3\n" \
- "\t.org 2b+%O4\n" \
+ "\t.short %O4\n" \
+ "\t.org 2b+%O5\n" \
"\t.popsection\n"
#endif

+#ifdef HAVE_BUG_FUNCTION
+# define __BUG_FUNC __func__
+#else
+# define __BUG_FUNC NULL
+#endif
+
#define BUG() \
do { \
__asm__ __volatile__ ( \
@@ -47,6 +62,7 @@ do { \
: \
: "n" (TRAPA_BUG_OPCODE), \
"i" (__FILE__), \
+ "i" (__BUG_FUNC), \
"i" (__LINE__), "i" (0), \
"i" (sizeof(struct bug_entry))); \
unreachable(); \
@@ -60,6 +76,7 @@ do { \
: \
: "n" (TRAPA_BUG_OPCODE), \
"i" (__FILE__), \
+ "i" (__BUG_FUNC), \
"i" (__LINE__), \
"i" (BUGFLAG_WARNING|(flags)), \
"i" (sizeof(struct bug_entry))); \
@@ -85,6 +102,7 @@ do { \
: \
: "n" (TRAPA_BUG_OPCODE), \
"i" (__FILE__), \
+ "i" (__BUG_FUNC), \
"i" (__LINE__), \
"i" (BUGFLAG_UNWINDER), \
"i" (sizeof(struct bug_entry))); \
--
2.39.2