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 * Since some emulators terminate on UD2, we cannot use it for WARN. 9 * Since various instruction decoders disagree on the length of UD1, 10 * we cannot use it either. So use UD0 for WARN. 11 * 12 * (binutils knows about "ud1" but {en,de}codes it as 2 bytes, whereas 13 * our kernel decoder thinks it takes a ModRM byte, which seems consistent 14 * with various things like the Intel SDM instruction encoding rules) 15 */ 16 17 #define ASM_UD0 ".byte 0x0f, 0xff" 18 #define ASM_UD1 ".byte 0x0f, 0xb9" /* + ModRM */ 19 #define ASM_UD2 ".byte 0x0f, 0x0b" 20 21 #define INSN_UD0 0xff0f 22 #define INSN_UD2 0x0b0f 23 24 #define LEN_UD0 2 25 26 #ifdef CONFIG_GENERIC_BUG 27 28 #ifdef CONFIG_X86_32 29 # define __BUG_REL(val) ".long " __stringify(val) 30 #else 31 # define __BUG_REL(val) ".long " __stringify(val) " - 2b" 32 #endif 33 34 #ifdef CONFIG_DEBUG_BUGVERBOSE 35 36 #define _BUG_FLAGS(ins, flags) \ 37 do { \ 38 asm volatile("1:\t" ins "\n" \ 39 ".pushsection __bug_table,\"aw\"\n" \ 40 "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \ 41 "\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \ 42 "\t.word %c1" "\t# bug_entry::line\n" \ 43 "\t.word %c2" "\t# bug_entry::flags\n" \ 44 "\t.org 2b+%c3\n" \ 45 ".popsection" \ 46 : : "i" (__FILE__), "i" (__LINE__), \ 47 "i" (flags), \ 48 "i" (sizeof(struct bug_entry))); \ 49 } while (0) 50 51 #else /* !CONFIG_DEBUG_BUGVERBOSE */ 52 53 #define _BUG_FLAGS(ins, flags) \ 54 do { \ 55 asm volatile("1:\t" ins "\n" \ 56 ".pushsection __bug_table,\"aw\"\n" \ 57 "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \ 58 "\t.word %c0" "\t# bug_entry::flags\n" \ 59 "\t.org 2b+%c1\n" \ 60 ".popsection" \ 61 : : "i" (flags), \ 62 "i" (sizeof(struct bug_entry))); \ 63 } while (0) 64 65 #endif /* CONFIG_DEBUG_BUGVERBOSE */ 66 67 #else 68 69 #define _BUG_FLAGS(ins, flags) asm volatile(ins) 70 71 #endif /* CONFIG_GENERIC_BUG */ 72 73 #define HAVE_ARCH_BUG 74 #define BUG() \ 75 do { \ 76 _BUG_FLAGS(ASM_UD2, 0); \ 77 unreachable(); \ 78 } while (0) 79 80 #define __WARN_FLAGS(flags) _BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags)) 81 82 #include <asm-generic/bug.h> 83 84 #endif /* _ASM_X86_BUG_H */ 85