[PATCH v2 14/14] powerpc: Add support for suppressing warning backtraces
From: Guenter Roeck <linux@roeck-us.net>
Date: 2024-03-25 17:53:18
Also in:
dri-devel, linux-arch, linux-arm-kernel, linux-doc, linux-kselftest, linux-riscv, linux-s390, linux-sh, lkml, loongarch, netdev
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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). Tested-by: Linux Kernel Functional Testing <redacted> Acked-by: Dan Carpenter <redacted> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- - Rebased to v6.9-rc1 - Added Tested-by:, Acked-by:, and Reviewed-by: tags - Introduced KUNIT_SUPPRESS_BACKTRACE configuration option arch/powerpc/include/asm/bug.h | 37 +++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 1db485aacbd9..5b06745d20aa 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/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)); \ } \
--
2.39.2