xref: /openbmc/linux/arch/x86/include/asm/bug.h (revision 132db935)
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 
7 /*
8  * Despite that some emulators terminate on UD2, we use it for WARN().
9  *
10  * Since various instruction decoders/specs disagree on the encoding of
11  * UD0/UD1.
12  */
13 
14 #define ASM_UD0		".byte 0x0f, 0xff" /* + ModRM (for Intel) */
15 #define ASM_UD1		".byte 0x0f, 0xb9" /* + ModRM */
16 #define ASM_UD2		".byte 0x0f, 0x0b"
17 
18 #define INSN_UD0	0xff0f
19 #define INSN_UD2	0x0b0f
20 
21 #define LEN_UD2		2
22 
23 #ifdef CONFIG_GENERIC_BUG
24 
25 #ifdef CONFIG_X86_32
26 # define __BUG_REL(val)	".long " __stringify(val)
27 #else
28 # define __BUG_REL(val)	".long " __stringify(val) " - 2b"
29 #endif
30 
31 #ifdef CONFIG_DEBUG_BUGVERBOSE
32 
33 #define _BUG_FLAGS(ins, flags)						\
34 do {									\
35 	asm_inline volatile("1:\t" ins "\n"				\
36 		     ".pushsection __bug_table,\"aw\"\n"		\
37 		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
38 		     "\t"  __BUG_REL(%c0) "\t# bug_entry::file\n"	\
39 		     "\t.word %c1"        "\t# bug_entry::line\n"	\
40 		     "\t.word %c2"        "\t# bug_entry::flags\n"	\
41 		     "\t.org 2b+%c3\n"					\
42 		     ".popsection"					\
43 		     : : "i" (__FILE__), "i" (__LINE__),		\
44 			 "i" (flags),					\
45 			 "i" (sizeof(struct bug_entry)));		\
46 } while (0)
47 
48 #else /* !CONFIG_DEBUG_BUGVERBOSE */
49 
50 #define _BUG_FLAGS(ins, flags)						\
51 do {									\
52 	asm_inline volatile("1:\t" ins "\n"				\
53 		     ".pushsection __bug_table,\"aw\"\n"		\
54 		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
55 		     "\t.word %c0"        "\t# bug_entry::flags\n"	\
56 		     "\t.org 2b+%c1\n"					\
57 		     ".popsection"					\
58 		     : : "i" (flags),					\
59 			 "i" (sizeof(struct bug_entry)));		\
60 } while (0)
61 
62 #endif /* CONFIG_DEBUG_BUGVERBOSE */
63 
64 #else
65 
66 #define _BUG_FLAGS(ins, flags)  asm volatile(ins)
67 
68 #endif /* CONFIG_GENERIC_BUG */
69 
70 #define HAVE_ARCH_BUG
71 #define BUG()							\
72 do {								\
73 	instrumentation_begin();				\
74 	_BUG_FLAGS(ASM_UD2, 0);					\
75 	unreachable();						\
76 } while (0)
77 
78 #define __WARN_FLAGS(flags)					\
79 do {								\
80 	instrumentation_begin();				\
81 	_BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags));		\
82 	annotate_reachable();					\
83 	instrumentation_end();					\
84 } while (0)
85 
86 #include <asm-generic/bug.h>
87 
88 #endif /* _ASM_X86_BUG_H */
89