[PATCH v3 10/15] parisc: Add support for suppressing warning backtraces

Guenter Roeck
2024-04-03T13:20:00Z

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_SUPPRESS_BACKTRACE 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).

While at it, declare assembler parameters as constants where possible.
Refine .blockz instructions to calculate the necessary padding instead
of using fixed values.

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2:
- Rebased to v6.9-rc1
- Added Tested-by:, Acked-by:, and Reviewed-by: tags
- Introduced KUNIT_SUPPRESS_BACKTRACE configuration option
v3:
- Rebased to v6.9-rc2

arch/parisc/include/asm/bug.h | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h
index 833555f74ffa..b59c3f7380bf 100644
--- a/arch/parisc/include/asm/bug.h
+++ b/arch/parisc/include/asm/bug.h
@@ -23,8 +23,17 @@
# define __BUG_REL(val) ".word " __stringify(val)
#endif

-
#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#ifdef CONFIG_KUNIT_SUPPRESS_BACKTRACE
+# 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 /* CONFIG_KUNIT_SUPPRESS_BACKTRACE */
+
#define BUG() \
do { \
asm volatile("\n" \
@@ -33,10 +42,12 @@
"\t.align 4\n" \
"2:\t" __BUG_REL(1b) "\n" \
"\t" __BUG_REL(%c0) "\n" \
- "\t.short %1, %2\n" \
- "\t.blockz %3-2*4-2*2\n" \
+ "\t" __BUG_FUNC_PTR "\n" \
+ "\t.short %c2, %c3\n" \
+ "\t.blockz %c4-(.-2b)\n" \
"\t.popsection" \
- : : "i" (__FILE__), "i" (__LINE__), \
+ : : "i" (__FILE__), "i" (__BUG_FUNC), \
+ "i" (__LINE__), \
"i" (0), "i" (sizeof(struct bug_entry)) ); \
unreachable(); \
} while(0)
@@ -58,10 +69,12 @@
"\t.align 4\n" \
"2:\t" __BUG_REL(1b) "\n" \
"\t" __BUG_REL(%c0) "\n" \
- "\t.short %1, %2\n" \
- "\t.blockz %3-2*4-2*2\n" \
+ "\t" __BUG_FUNC_PTR "\n" \
+ "\t.short %c2, %3\n" \
+ "\t.blockz %c4-(.-2b)\n" \
"\t.popsection" \
- : : "i" (__FILE__), "i" (__LINE__), \
+ : : "i" (__FILE__), "i" (__BUG_FUNC), \
+ "i" (__LINE__), \
"i" (BUGFLAG_WARNING|(flags)), \
"i" (sizeof(struct bug_entry)) ); \
} while(0)
@@ -74,7 +87,7 @@
"\t.align 4\n" \
"2:\t" __BUG_REL(1b) "\n" \
"\t.short %0\n" \
- "\t.blockz %1-4-2\n" \
+ "\t.blockz %c1-(.-2b)\n" \
"\t.popsection" \
: : "i" (BUGFLAG_WARNING|(flags)), \
"i" (sizeof(struct bug_entry)) ); \
--
2.39.2