1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_BUG_H
3#define _ASM_X86_BUG_H
4
5#include <linux/stringify.h>
6#include <linux/instrumentation.h>
7#include <linux/objtool.h>
8
9/*
10 * Despite that some emulators terminate on UD2, we use it for WARN().
11 */
12#define ASM_UD2		".byte 0x0f, 0x0b"
13#define INSN_UD2	0x0b0f
14#define LEN_UD2		2
15
16#ifdef CONFIG_GENERIC_BUG
17
18#ifdef CONFIG_X86_32
19# define __BUG_REL(val)	".long " __stringify(val)
20#else
21# define __BUG_REL(val)	".long " __stringify(val) " - ."
22#endif
23
24#ifdef CONFIG_DEBUG_BUGVERBOSE
25
26#define _BUG_FLAGS(ins, flags, extra)					\
27do {									\
28	asm_inline volatile("1:\t" ins "\n"				\
29		     ".pushsection __bug_table,\"aw\"\n"		\
30		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
31		     "\t"  __BUG_REL(%c0) "\t# bug_entry::file\n"	\
32		     "\t.word %c1"        "\t# bug_entry::line\n"	\
33		     "\t.word %c2"        "\t# bug_entry::flags\n"	\
34		     "\t.org 2b+%c3\n"					\
35		     ".popsection\n"					\
36		     extra						\
37		     : : "i" (__FILE__), "i" (__LINE__),		\
38			 "i" (flags),					\
39			 "i" (sizeof(struct bug_entry)));		\
40} while (0)
41
42#else /* !CONFIG_DEBUG_BUGVERBOSE */
43
44#define _BUG_FLAGS(ins, flags, extra)					\
45do {									\
46	asm_inline volatile("1:\t" ins "\n"				\
47		     ".pushsection __bug_table,\"aw\"\n"		\
48		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
49		     "\t.word %c0"        "\t# bug_entry::flags\n"	\
50		     "\t.org 2b+%c1\n"					\
51		     ".popsection\n"					\
52		     extra						\
53		     : : "i" (flags),					\
54			 "i" (sizeof(struct bug_entry)));		\
55} while (0)
56
57#endif /* CONFIG_DEBUG_BUGVERBOSE */
58
59#else
60
61#define _BUG_FLAGS(ins, flags, extra)  asm volatile(ins)
62
63#endif /* CONFIG_GENERIC_BUG */
64
65#define HAVE_ARCH_BUG
66#define BUG()							\
67do {								\
68	instrumentation_begin();				\
69	_BUG_FLAGS(ASM_UD2, 0, "");				\
70	__builtin_unreachable();				\
71} while (0)
72
73/*
74 * This instrumentation_begin() is strictly speaking incorrect; but it
75 * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
76 * were to trigger, we'd rather wreck the machine in an attempt to get the
77 * message out than not know about it.
78 */
79#define __WARN_FLAGS(flags)					\
80do {								\
81	__auto_type __flags = BUGFLAG_WARNING|(flags);		\
82	instrumentation_begin();				\
83	_BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE);		\
84	instrumentation_end();					\
85} while (0)
86
87#include <asm-generic/bug.h>
88
89#endif /* _ASM_X86_BUG_H */
90