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 #include <linux/instrumentation.h>
   7 #include <linux/objtool.h>
   8
   9 /*
  10  * Despite that some emulators terminate on UD2, we use it for WARN().
  11  */
  12 #define ASM_UD2         ".byte 0x0f, 0x0b"
  13 #define INSN_UD2        0x0b0f
  14 #define LEN_UD2         2
  15
  16 /*
  17  * In clang we have UD1s reporting UBSAN failures on X86, 64 and 32bit.
  18  */
  19 #define INSN_ASOP               0x67
  20 #define OPCODE_ESCAPE           0x0f
  21 #define SECOND_BYTE_OPCODE_UD1  0xb9
  22 #define SECOND_BYTE_OPCODE_UD2  0x0b
  23
  24 #define BUG_NONE                0xffff
  25 #define BUG_UD1                 0xfffe
  26 #define BUG_UD2                 0xfffd
  27
  28 #ifdef CONFIG_GENERIC_BUG
  29
  30 #ifdef CONFIG_X86_32
  31 # define __BUG_REL(val) ".long " __stringify(val)
  32 #else
  33 # define __BUG_REL(val) ".long " __stringify(val) " - ."
  34 #endif
  35
  36 #ifdef CONFIG_DEBUG_BUGVERBOSE
  37
  38 #define _BUG_FLAGS(ins, flags, extra)                                   \
  39 do {                                                                    \
  40         asm_inline volatile("1:\t" ins "\n"                             \
  41                      ".pushsection __bug_table,\"aw\"\n"                \
  42                      "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"   \
  43                      "\t"  __BUG_REL(%c0) "\t# bug_entry::file\n"       \
  44                      "\t.word %c1"        "\t# bug_entry::line\n"       \
  45                      "\t.word %c2"        "\t# bug_entry::flags\n"      \
  46                      "\t.org 2b+%c3\n"                                  \
  47                      ".popsection\n"                                    \
  48                      extra                                              \
  49                      : : "i" (__FILE__), "i" (__LINE__),                \
  50                          "i" (flags),                                   \
  51                          "i" (sizeof(struct bug_entry)));               \
  52 } while (0)
  53
  54 #else /* !CONFIG_DEBUG_BUGVERBOSE */
  55
  56 #define _BUG_FLAGS(ins, flags, extra)                                   \
  57 do {                                                                    \
  58         asm_inline volatile("1:\t" ins "\n"                             \
  59                      ".pushsection __bug_table,\"aw\"\n"                \
  60                      "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"   \
  61                      "\t.word %c0"        "\t# bug_entry::flags\n"      \
  62                      "\t.org 2b+%c1\n"                                  \
  63                      ".popsection\n"                                    \
  64                      extra                                              \
  65                      : : "i" (flags),                                   \
  66                          "i" (sizeof(struct bug_entry)));               \
  67 } while (0)
  68
  69 #endif /* CONFIG_DEBUG_BUGVERBOSE */
  70
  71 #else
  72
  73 #define _BUG_FLAGS(ins, flags, extra)  asm volatile(ins)
  74
  75 #endif /* CONFIG_GENERIC_BUG */
  76
  77 #define HAVE_ARCH_BUG
  78 #define BUG()                                                   \
  79 do {                                                            \
  80         instrumentation_begin();                                \
  81         _BUG_FLAGS(ASM_UD2, 0, "");                             \
  82         __builtin_unreachable();                                \
  83 } while (0)
  84
  85 /*
  86  * This instrumentation_begin() is strictly speaking incorrect; but it
  87  * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
  88  * were to trigger, we'd rather wreck the machine in an attempt to get the
  89  * message out than not know about it.
  90  */
  91 #define __WARN_FLAGS(flags)                                     \
  92 do {                                                            \
  93         __auto_type __flags = BUGFLAG_WARNING|(flags);          \
  94         instrumentation_begin();                                \
  95         _BUG_FLAGS(ASM_UD2, __flags, ANNOTATE_REACHABLE(1b));   \
  96         instrumentation_end();                                  \
  97 } while (0)
  98
  99 #include <asm-generic/bug.h>
 100
 101 #endif /* _ASM_X86_BUG_H */