The patch titled
Subject: powerpc: add support for suppressing warning backtraces
has been added to the -mm mm-nonmm-unstable branch. Its filename is
powerpc-add-support-for-suppressing-warning-backtraces.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-add-support-for-suppressing-warning-backtraces.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Guenter Roeck <linux@xxxxxxxxxxxx>
Subject: powerpc: add support for suppressing warning backtraces
Date: Thu, 13 Mar 2025 11:43:29 +0000
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).
Link: https://lkml.kernel.org/r/20250313114329.284104-15-acarmina@xxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Alessandro Carminati <acarmina@xxxxxxxxxx>
Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Acked-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: Brendan Higgins <brendan.higgins@xxxxxxxxx>
Cc: David Gow <davidgow@xxxxxxxxxx>
Cc: Rae Moar <rmoar@xxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Arthur Grillo <arthurgrillo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Charlie Jenkins <charlie@xxxxxxxxxxxx>
Cc: Daniel Diaz <daniel.diaz@xxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: MaÃra Canal <mcanal@xxxxxxxxxx>
Cc: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Simon Horman <horms@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Zimemrmann <tzimmermann@xxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/bug.h | 37 +++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 9 deletions(-)
--- a/arch/powerpc/include/asm/bug.h~powerpc-add-support-for-suppressing-warning-backtraces
+++ a/arch/powerpc/include/asm/bug.h
@@ -14,6 +14,9 @@
.section __bug_table,"aw"
5001: .4byte \addr - .
.4byte 5002f - .
+#ifdef CONFIG_KUNIT_SUPPRESS_BACKTRACE
+ .4byte 0
+#endif
.short \line, \flags
.org 5001b+BUG_ENTRY_SIZE
.previous
@@ -32,30 +35,46 @@
#endif /* verbose */
#else /* !__ASSEMBLY__ */
-/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
- sizeof(struct bug_entry), respectively */
+/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3,%4 to be FILE, __func__, LINE, flags
+ and sizeof(struct bug_entry), respectively */
#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#ifdef CONFIG_KUNIT_SUPPRESS_BACKTRACE
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR " .4byte %1 - .\n"
+#else
+# define __BUG_FUNC_PTR
+#endif /* CONFIG_KUNIT_SUPPRESS_BACKTRACE */
+
#define _EMIT_BUG_ENTRY \
".section __bug_table,\"aw\"\n" \
"2: .4byte 1b - .\n" \
" .4byte %0 - .\n" \
- " .short %1, %2\n" \
- ".org 2b+%3\n" \
+ __BUG_FUNC_PTR \
+ " .short %2, %3\n" \
+ ".org 2b+%4\n" \
".previous\n"
#else
#define _EMIT_BUG_ENTRY \
".section __bug_table,\"aw\"\n" \
"2: .4byte 1b - .\n" \
- " .short %2\n" \
- ".org 2b+%3\n" \
+ " .short %3\n" \
+ ".org 2b+%4\n" \
".previous\n"
#endif
+#ifdef HAVE_BUG_FUNCTION
+# define __BUG_FUNC __func__
+#else
+# define __BUG_FUNC NULL
+#endif
+
#define BUG_ENTRY(insn, flags, ...) \
__asm__ __volatile__( \
"1: " insn "\n" \
_EMIT_BUG_ENTRY \
- : : "i" (__FILE__), "i" (__LINE__), \
+ : : "i" (__FILE__), "i" (__BUG_FUNC), \
+ "i" (__LINE__), \
"i" (flags), \
"i" (sizeof(struct bug_entry)), \
##__VA_ARGS__)
@@ -80,7 +99,7 @@
if (x) \
BUG(); \
} else { \
- BUG_ENTRY(PPC_TLNEI " %4, 0", 0, "r" ((__force long)(x))); \
+ BUG_ENTRY(PPC_TLNEI " %5, 0", 0, "r" ((__force long)(x))); \
} \
} while (0)
@@ -90,7 +109,7 @@
if (__ret_warn_on) \
__WARN(); \
} else { \
- BUG_ENTRY(PPC_TLNEI " %4, 0", \
+ BUG_ENTRY(PPC_TLNEI " %5, 0", \
BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN), \
"r" (__ret_warn_on)); \
} \
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxx are
bug-kunit-core-support-for-suppressing-warning-backtraces.patch
kunit-bug-count-suppressed-warning-backtraces.patch
kunit-add-test-cases-for-backtrace-warning-suppression.patch
kunit-add-documentation-for-warning-backtrace-suppression-api.patch
drm-suppress-intentional-warning-backtraces-in-scaling-unit-tests.patch
x86-add-support-for-suppressing-warning-backtraces.patch
arm64-add-support-for-suppressing-warning-backtraces.patch
loongarch-add-support-for-suppressing-warning-backtraces.patch
parisc-add-support-for-suppressing-warning-backtraces.patch
s390-add-support-for-suppressing-warning-backtraces.patch
sh-add-support-for-suppressing-warning-backtraces.patch
sh-move-defines-needed-for-suppressing-warning-backtraces.patch
riscv-add-support-for-suppressing-warning-backtraces.patch
powerpc-add-support-for-suppressing-warning-backtraces.patch
