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)                                          \
  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"                                      \
  35                      : : "i" (__FILE__), "i" (__LINE__),                \
  36                          "i" (flags),                                   \
  37                          "i" (sizeof(struct bug_entry)));               \
  38 } while (0)
  39
  40 #else /* !CONFIG_DEBUG_BUGVERBOSE */
  41
  42 #define _BUG_FLAGS(ins, flags)                                          \
  43 do {                                                                    \
  44         asm_inline volatile("1:\t" ins "\n"                             \
  45                      ".pushsection __bug_table,\"aw\"\n"                \
  46                      "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"   \
  47                      "\t.word %c0"        "\t# bug_entry::flags\n"      \
  48                      "\t.org 2b+%c1\n"                                  \
  49                      ".popsection"                                      \
  50                      : : "i" (flags),                                   \
  51                          "i" (sizeof(struct bug_entry)));               \
  52 } while (0)
  53
  54 #endif /* CONFIG_DEBUG_BUGVERBOSE */
  55
  56 #else
  57
  58 #define _BUG_FLAGS(ins, flags)  asm volatile(ins)
  59
  60 #endif /* CONFIG_GENERIC_BUG */
  61
  62 #define HAVE_ARCH_BUG
  63 #define BUG()                                                   \
  64 do {                                                            \
  65         instrumentation_begin();                                \
  66         _BUG_FLAGS(ASM_UD2, 0);                                 \
  67         unreachable();                                          \
  68 } while (0)
  69
  70 /*
  71  * This instrumentation_begin() is strictly speaking incorrect; but it
  72  * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
  73  * were to trigger, we'd rather wreck the machine in an attempt to get the
  74  * message out than not know about it.
  75  */
  76 #define __WARN_FLAGS(flags)                                     \
  77 do {                                                            \
  78         instrumentation_begin();                                \
  79         _BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags));           \
  80         annotate_reachable();                                   \
  81         instrumentation_end();                                  \
  82 } while (0)
  83
  84 #include <asm-generic/bug.h>
  85
  86 #endif /* _ASM_X86_BUG_H */