[PATCH 11/14] s390: Add support for suppressing warning backtraces

Guenter Roeck
2024-03-12T17:03:40Z

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/s390/include/asm/bug.h | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index aebe1e22c7be..01e2aa4069d7 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -8,19 +8,30 @@

#ifdef CONFIG_DEBUG_BUGVERBOSE

+#if IS_ENABLED(CONFIG_KUNIT)
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR " .long %0-.\n"
+# define __BUG_FUNC __func__
+#else
+# define __BUG_FUNC_PTR
+# define __BUG_FUNC NULL
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
#define __EMIT_BUG(x) do { \
asm_inline volatile( \
"0: mc 0,0\n" \
".section .rodata.str,\"aMS\",@progbits,1\n" \
"1: .asciz \""__FILE__"\"\n" \
".previous\n" \
- ".section __bug_table,\"awM\",@progbits,%2\n" \
+ ".section __bug_table,\"awM\",@progbits,%3\n" \
"2: .long 0b-.\n" \
" .long 1b-.\n" \
- " .short %0,%1\n" \
- " .org 2b+%2\n" \
+ __BUG_FUNC_PTR \
+ " .short %1,%2\n" \
+ " .org 2b+%3\n" \
".previous\n" \
- : : "i" (__LINE__), \
+ : : "i" (__BUG_FUNC), \
+ "i" (__LINE__), \
"i" (x), \
"i" (sizeof(struct bug_entry))); \
} while (0)
--
2.39.2