bug.h

  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 */