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