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linux-next/arch/x86/include/asm/bug.h
Thomas Gleixner 5916d5f9b3 bug: Annotate WARN/BUG/stackfail as noinstr safe
Warnings, bugs and stack protection fails from noinstr sections, e.g. low
level and early entry code, are likely to be fatal.

Mark them as "safe" to be invoked from noinstr protected code to avoid
annotating all usage sites. Getting the information out is important.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.376598577@linutronix.de
2020-06-11 15:14:36 +02:00

89 lines
2.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_BUG_H
#define _ASM_X86_BUG_H
#include <linux/stringify.h>
/*
* Despite that some emulators terminate on UD2, we use it for WARN().
*
* Since various instruction decoders/specs disagree on the encoding of
* UD0/UD1.
*/
#define ASM_UD0 ".byte 0x0f, 0xff" /* + ModRM (for Intel) */
#define ASM_UD1 ".byte 0x0f, 0xb9" /* + ModRM */
#define ASM_UD2 ".byte 0x0f, 0x0b"
#define INSN_UD0 0xff0f
#define INSN_UD2 0x0b0f
#define LEN_UD2 2
#ifdef CONFIG_GENERIC_BUG
#ifdef CONFIG_X86_32
# define __BUG_REL(val) ".long " __stringify(val)
#else
# define __BUG_REL(val) ".long " __stringify(val) " - 2b"
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUG_FLAGS(ins, flags) \
do { \
asm_inline volatile("1:\t" ins "\n" \
".pushsection __bug_table,\"aw\"\n" \
"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
"\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
"\t.word %c1" "\t# bug_entry::line\n" \
"\t.word %c2" "\t# bug_entry::flags\n" \
"\t.org 2b+%c3\n" \
".popsection" \
: : "i" (__FILE__), "i" (__LINE__), \
"i" (flags), \
"i" (sizeof(struct bug_entry))); \
} while (0)
#else /* !CONFIG_DEBUG_BUGVERBOSE */
#define _BUG_FLAGS(ins, flags) \
do { \
asm_inline volatile("1:\t" ins "\n" \
".pushsection __bug_table,\"aw\"\n" \
"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
"\t.word %c0" "\t# bug_entry::flags\n" \
"\t.org 2b+%c1\n" \
".popsection" \
: : "i" (flags), \
"i" (sizeof(struct bug_entry))); \
} while (0)
#endif /* CONFIG_DEBUG_BUGVERBOSE */
#else
#define _BUG_FLAGS(ins, flags) asm volatile(ins)
#endif /* CONFIG_GENERIC_BUG */
#define HAVE_ARCH_BUG
#define BUG() \
do { \
instrumentation_begin(); \
_BUG_FLAGS(ASM_UD2, 0); \
unreachable(); \
} while (0)
#define __WARN_FLAGS(flags) \
do { \
instrumentation_begin(); \
_BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags)); \
annotate_reachable(); \
instrumentation_end(); \
} while (0)
#include <asm-generic/bug.h>
#endif /* _ASM_X86_BUG_H */