LXR linux/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)                                          \
  26do {                                                                    \
  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)                                          \
  43do {                                                                    \
  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()                                                   \
  64do {                                                            \
  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)                                     \
  77do {                                                            \
  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 */
  87