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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#include <asm/asm.h>
9
10#ifndef __ASSEMBLY__
11struct bug_entry;
12extern void __WARN_trap(struct bug_entry *bug, ...);
13#endif
14
15/*
16 * Despite that some emulators terminate on UD2, we use it for WARN().
17 */
18#define ASM_UD2 __ASM_FORM(ud2)
19#define INSN_UD2 0x0b0f
20#define LEN_UD2 2
21
22#define ASM_UDB _ASM_BYTES(0xd6)
23#define INSN_UDB 0xd6
24#define LEN_UDB 1
25
26/*
27 * In clang we have UD1s reporting UBSAN failures on X86, 64 and 32bit.
28 */
29#define INSN_ASOP 0x67
30#define INSN_LOCK 0xf0
31#define OPCODE_ESCAPE 0x0f
32#define SECOND_BYTE_OPCODE_UD1 0xb9
33#define SECOND_BYTE_OPCODE_UD2 0x0b
34
35#define BUG_NONE 0xffff
36#define BUG_UD2 0xfffe
37#define BUG_UD1 0xfffd
38#define BUG_UD1_UBSAN 0xfffc
39#define BUG_UD1_WARN 0xfffb
40#define BUG_UDB 0xffd6
41#define BUG_LOCK 0xfff0
42
43#ifdef CONFIG_GENERIC_BUG
44
45#ifdef CONFIG_DEBUG_BUGVERBOSE
46#define __BUG_ENTRY_VERBOSE(file, line) \
47 "\t.long " file " - .\t# bug_entry::file\n" \
48 "\t.word " line "\t# bug_entry::line\n"
49#else
50#define __BUG_ENTRY_VERBOSE(file, line)
51#endif
52
53#if defined(CONFIG_X86_64) || defined(CONFIG_DEBUG_BUGVERBOSE_DETAILED)
54#define HAVE_ARCH_BUG_FORMAT
55#define __BUG_ENTRY_FORMAT(format) \
56 "\t.long " format " - .\t# bug_entry::format\n"
57#else
58#define __BUG_ENTRY_FORMAT(format)
59#endif
60
61#ifdef CONFIG_X86_64
62#define HAVE_ARCH_BUG_FORMAT_ARGS
63#endif
64
65#define __BUG_ENTRY(format, file, line, flags) \
66 "\t.long 1b - ." "\t# bug_entry::bug_addr\n" \
67 __BUG_ENTRY_FORMAT(format) \
68 __BUG_ENTRY_VERBOSE(file, line) \
69 "\t.word " flags "\t# bug_entry::flags\n"
70
71#define _BUG_FLAGS_ASM(format, file, line, flags, size, extra) \
72 ".pushsection __bug_table,\"aw\"\n\t" \
73 ANNOTATE_DATA_SPECIAL "\n\t" \
74 "2:\n\t" \
75 __BUG_ENTRY(format, file, line, flags) \
76 "\t.org 2b + " size "\n" \
77 ".popsection\n" \
78 extra
79
80#ifdef CONFIG_DEBUG_BUGVERBOSE_DETAILED
81#define WARN_CONDITION_STR(cond_str) cond_str
82#else
83#define WARN_CONDITION_STR(cond_str) ""
84#endif
85
86#define _BUG_FLAGS(cond_str, ins, flags, extra) \
87do { \
88 asm_inline volatile("1:\t" ins "\n" \
89 _BUG_FLAGS_ASM("%c[fmt]", "%c[file]", \
90 "%c[line]", "%c[fl]", \
91 "%c[size]", extra) \
92 : : [fmt] "i" (WARN_CONDITION_STR(cond_str)), \
93 [file] "i" (__FILE__), \
94 [line] "i" (__LINE__), \
95 [fl] "i" (flags), \
96 [size] "i" (sizeof(struct bug_entry))); \
97} while (0)
98
99#define ARCH_WARN_ASM(file, line, flags, size) \
100 ".pushsection .rodata.str1.1, \"aMS\", @progbits, 1\n" \
101 "99:\n" \
102 "\t.string \"\"\n" \
103 ".popsection\n" \
104 "1:\t " ASM_UD2 "\n" \
105 _BUG_FLAGS_ASM("99b", file, line, flags, size, "")
106
107#else
108
109#define _BUG_FLAGS(cond_str, ins, flags, extra) asm volatile(ins)
110
111#endif /* CONFIG_GENERIC_BUG */
112
113#define HAVE_ARCH_BUG
114#define BUG() \
115do { \
116 instrumentation_begin(); \
117 _BUG_FLAGS("", ASM_UD2, 0, ""); \
118 __builtin_unreachable(); \
119} while (0)
120
121/*
122 * This instrumentation_begin() is strictly speaking incorrect; but it
123 * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
124 * were to trigger, we'd rather wreck the machine in an attempt to get the
125 * message out than not know about it.
126 */
127
128#define ARCH_WARN_REACHABLE ANNOTATE_REACHABLE(1b)
129
130#define __WARN_FLAGS(cond_str, flags) \
131do { \
132 auto __flags = BUGFLAG_WARNING|(flags); \
133 instrumentation_begin(); \
134 _BUG_FLAGS(cond_str, ASM_UD2, __flags, ARCH_WARN_REACHABLE); \
135 instrumentation_end(); \
136} while (0)
137
138#ifdef HAVE_ARCH_BUG_FORMAT_ARGS
139
140#ifndef __ASSEMBLY__
141#include <linux/static_call_types.h>
142DECLARE_STATIC_CALL(WARN_trap, __WARN_trap);
143
144struct pt_regs;
145struct sysv_va_list { /* from AMD64 System V ABI */
146 unsigned int gp_offset;
147 unsigned int fp_offset;
148 void *overflow_arg_area;
149 void *reg_save_area;
150};
151struct arch_va_list {
152 unsigned long regs[6];
153 struct sysv_va_list args;
154};
155extern void *__warn_args(struct arch_va_list *args, struct pt_regs *regs);
156#endif /* __ASSEMBLY__ */
157
158#define __WARN_bug_entry(flags, format) ({ \
159 struct bug_entry *bug; \
160 asm_inline volatile("lea (2f)(%%rip), %[addr]\n1:\n" \
161 _BUG_FLAGS_ASM("%c[fmt]", "%c[file]", \
162 "%c[line]", "%c[fl]", \
163 "%c[size]", "") \
164 : [addr] "=r" (bug) \
165 : [fmt] "i" (format), \
166 [file] "i" (__FILE__), \
167 [line] "i" (__LINE__), \
168 [fl] "i" (flags), \
169 [size] "i" (sizeof(struct bug_entry))); \
170 bug; })
171
172#define __WARN_print_arg(flags, format, arg...) \
173do { \
174 int __flags = (flags) | BUGFLAG_WARNING | BUGFLAG_ARGS ; \
175 static_call_mod(WARN_trap)(__WARN_bug_entry(__flags, format), ## arg); \
176 asm (""); /* inhibit tail-call optimization */ \
177} while (0)
178
179#define __WARN_printf(taint, fmt, arg...) \
180 __WARN_print_arg(BUGFLAG_TAINT(taint), fmt, ## arg)
181
182#define WARN_ONCE(cond, format, arg...) ({ \
183 int __ret_warn_on = !!(cond); \
184 if (unlikely(__ret_warn_on)) { \
185 __WARN_print_arg(BUGFLAG_ONCE|BUGFLAG_TAINT(TAINT_WARN),\
186 format, ## arg); \
187 } \
188 __ret_warn_on; \
189})
190
191#endif /* HAVE_ARCH_BUG_FORMAT_ARGS */
192
193#include <asm-generic/bug.h>
194
195#endif /* _ASM_X86_BUG_H */
196

source code of linux/arch/x86/include/asm/bug.h