arm64: Add ASM_BUG()

Currently. we can only use BUG() from C code, though there are
situations where we would like an equivalent mechanism in assembly code.

This patch refactors our BUG() definition such that it can be used in
either C or assembly, in the form of a new ASM_BUG().

The refactoring requires the removal of escape sequences, such as '\n'
and '\t', but these aren't strictly necessary as we can use ';' to
terminate assembler statements.

The low-level assembly is factored out into <asm/asm-bug.h>, with
<asm/bug.h> retained as the C wrapper.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Mark Rutland 2017-07-26 14:41:40 +01:00
parent 16f73eb02d
commit db44e9c5ec
2 changed files with 57 additions and 32 deletions

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@ -0,0 +1,54 @@
#ifndef __ASM_ASM_BUG_H
/*
* Copyright (C) 2017 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define __ASM_ASM_BUG_H
#include <asm/brk-imm.h>
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line)
#define __BUGVERBOSE_LOCATION(file, line) \
.pushsection .rodata.str,"aMS",@progbits,1; \
2: .string file; \
.popsection; \
\
.long 2b - 0b; \
.short line;
#else
#define _BUGVERBOSE_LOCATION(file, line)
#endif
#ifdef CONFIG_GENERIC_BUG
#define __BUG_ENTRY(flags) \
.pushsection __bug_table,"aw"; \
.align 2; \
0: .long 1f - 0b; \
_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
.short flags; \
.popsection; \
1:
#else
#define __BUG_ENTRY(flags)
#endif
#define ASM_BUG_FLAGS(flags) \
__BUG_ENTRY(flags) \
brk BUG_BRK_IMM
#define ASM_BUG() ASM_BUG_FLAGS(0)
#endif /* __ASM_ASM_BUG_H */

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@ -18,41 +18,12 @@
#ifndef _ARCH_ARM64_ASM_BUG_H
#define _ARCH_ARM64_ASM_BUG_H
#include <asm/brk-imm.h>
#include <linux/stringify.h>
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line)
#define __BUGVERBOSE_LOCATION(file, line) \
".pushsection .rodata.str,\"aMS\",@progbits,1\n" \
"2: .string \"" file "\"\n\t" \
".popsection\n\t" \
\
".long 2b - 0b\n\t" \
".short " #line "\n\t"
#else
#define _BUGVERBOSE_LOCATION(file, line)
#endif
#ifdef CONFIG_GENERIC_BUG
#define __BUG_ENTRY(flags) \
".pushsection __bug_table,\"aw\"\n\t" \
".align 2\n\t" \
"0: .long 1f - 0b\n\t" \
_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
".short " #flags "\n\t" \
".popsection\n" \
"1: "
#else
#define __BUG_ENTRY(flags) ""
#endif
#include <asm/asm-bug.h>
#define __BUG_FLAGS(flags) \
asm volatile ( \
__BUG_ENTRY(flags) \
"brk %[imm]" :: [imm] "i" (BUG_BRK_IMM) \
);
asm volatile (__stringify(ASM_BUG_FLAGS(flags)));
#define BUG() do { \
__BUG_FLAGS(0); \