arch/x86/include/asm/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
   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 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 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         _BUG_FLAGS(ASM_UD2, 0);                                 \
  74         unreachable();                                          \
  75 } while (0)
  76
  77 #define __WARN_FLAGS(flags)                                     \
  78 do {                                                            \
  79         _BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags));           \
  80         annotate_reachable();                                   \
  81 } while (0)
  82
  83 #include <asm-generic/bug.h>
  84
  85 #endif /* _ASM_X86_BUG_H */