From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
To: linux-arm-kernel@lists.infradead.org
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>,
Russell King <linux@armlinux.org.uk>,
Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 01/11] ARM: BUG: Move the assembly out of __BUG() macro
Date: Sat, 10 Oct 2026 00:21:08 +0200 [thread overview]
Message-ID: <20261010-arm_warning-v1-1-ddf4be42ae0d@breakpoint.cc> (raw)
In-Reply-To: <20261010-arm_warning-v1-0-ddf4be42ae0d@breakpoint.cc>
Move the assembly line from within the __BUG() macro into its own
define. The quotation marks and the string escape can be removed and
instead the resulting __BUG__LINE() macro can be wrapped into
__stringify() to achieve the same.
The BUG_INSTR() expects a string context. This can be replaced with
___asm_opcode_to_mem_arm()/_thumb16() macro. Wrap this into
BUG_ENCODING() macro.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
arch/arm/include/asm/bug.h | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h
index ba8d9d7d242bd..24f46d4f6e733 100644
--- a/arch/arm/include/asm/bug.h
+++ b/arch/arm/include/asm/bug.h
@@ -14,9 +14,11 @@
#ifdef CONFIG_THUMB2_KERNEL
#define BUG_INSTR_VALUE 0xde02
#define BUG_INSTR(__value) __inst_thumb16(__value)
+#define BUG_ENCODING() .short ___asm_opcode_to_mem_thumb16(BUG_INSTR_VALUE)
#else
#define BUG_INSTR_VALUE 0xe7f001f2
#define BUG_INSTR(__value) __inst_arm(__value)
+#define BUG_ENCODING() .long ___asm_opcode_to_mem_arm(BUG_INSTR_VALUE)
#endif
@@ -25,24 +27,27 @@
#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define __BUG__LINE(__file, __line, __value) \
+ 1: ; \
+ BUG_ENCODING(); \
+ .pushsection .rodata.str, "aMS", %progbits, 1; \
+ 2: .asciz __file; \
+ .popsection; \
+ .pushsection __bug_table,"aw"; \
+ .align 2; \
+ 3: .word 1b, 2b; \
+ .hword __line , 0; \
+ .popsection;
+
/*
* The extra indirection is to ensure that the __FILE__ string comes through
* OK. Many version of gcc do not support the asm %c parameter which would be
* preferable to this unpleasantness. We use mergeable string sections to
* avoid multiple copies of the string appearing in the kernel image.
*/
-
#define __BUG(__file, __line, __value) \
do { \
- asm volatile("1:\t" BUG_INSTR(__value) "\n" \
- ".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \
- "2:\t.asciz " #__file "\n" \
- ".popsection\n" \
- ".pushsection __bug_table,\"aw\"\n" \
- ".align 2\n" \
- "3:\t.word 1b, 2b\n" \
- "\t.hword " #__line ", 0\n" \
- ".popsection"); \
+ asm volatile(__stringify(__BUG__LINE(__file, __line, __value))); \
unreachable(); \
} while (0)
--
2.55.0
next prev parent reply other threads:[~2026-10-09 22:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 22:21 [PATCH 00/11] ARM: Use invalid opcode also for warnings Sebastian Andrzej Siewior
2026-10-09 22:21 ` Sebastian Andrzej Siewior [this message]
2026-10-09 22:21 ` [PATCH 02/11] ARM: BUG: Spent each entry in __BUG__LINE() its own line Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 03/11] ARM: BUG: Move the section right after the opcode Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 04/11] ARM: BUG: Move file/ line encoding into a custom macro Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 05/11] ARM: BUG: Move __bug_table creation to __BUG_ENTRY_GENERIC() macro Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 06/11] ARM: BUG: Move the __BUG() out of CONFIG_DEBUG_BUGVERBOSE Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 07/11] ARM: BUG: Pass a flags argument to __BUG__LINE() Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 08/11] ARM: BUG: Move BUG() into the do-while loop Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 09/11] ARM: traps: Move the BUG handling from die() to do_undefinstr() Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 10/11] ARM: traps: Add handling for warnings to handle_bug_opcode() Sebastian Andrzej Siewior
2026-10-09 22:21 ` [PATCH 11/11] ARM: BUG: Add WARN support via __WARN_FLAGS() Sebastian Andrzej Siewior
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