LXR linux/arch/x86/include/asm/bug.h

   1#ifndef _ASM_X86_BUG_H
   2#define _ASM_X86_BUG_H
   3
   4#include <linux/stringify.h>
   5
   6/*
   7 * Since some emulators terminate on UD2, we cannot use it for WARN.
   8 * Since various instruction decoders disagree on the length of UD1,
   9 * we cannot use it either. So use UD0 for WARN.
  10 *
  11 * (binutils knows about "ud1" but {en,de}codes it as 2 bytes, whereas
  12 *  our kernel decoder thinks it takes a ModRM byte, which seems consistent
  13 *  with various things like the Intel SDM instruction encoding rules)
  14 */
  15
  16#define ASM_UD0         ".byte 0x0f, 0xff"
  17#define ASM_UD1         ".byte 0x0f, 0xb9" /* + ModRM */
  18#define ASM_UD2         ".byte 0x0f, 0x0b"
  19
  20#define INSN_UD0        0xff0f
  21#define INSN_UD2        0x0b0f
  22
  23#define LEN_UD0         2
  24
  25#ifdef CONFIG_GENERIC_BUG
  26
  27#ifdef CONFIG_X86_32
  28# define __BUG_REL(val) ".long " __stringify(val)
  29#else
  30# define __BUG_REL(val) ".long " __stringify(val) " - 2b"
  31#endif
  32
  33#ifdef CONFIG_DEBUG_BUGVERBOSE
  34
  35#define _BUG_FLAGS(ins, flags)                                          \
  36do {                                                                    \
  37        asm volatile("1:\t" ins "\n"                                    \
  38                     ".pushsection __bug_table,\"aw\"\n"                \
  39                     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"   \
  40                     "\t"  __BUG_REL(%c0) "\t# bug_entry::file\n"       \
  41                     "\t.word %c1"        "\t# bug_entry::line\n"       \
  42                     "\t.word %c2"        "\t# bug_entry::flags\n"      \
  43                     "\t.org 2b+%c3\n"                                  \
  44                     ".popsection"                                      \
  45                     : : "i" (__FILE__), "i" (__LINE__),                \
  46                         "i" (flags),                                   \
  47                         "i" (sizeof(struct bug_entry)));               \
  48} while (0)
  49
  50#else /* !CONFIG_DEBUG_BUGVERBOSE */
  51
  52#define _BUG_FLAGS(ins, flags)                                          \
  53do {                                                                    \
  54        asm volatile("1:\t" ins "\n"                                    \
  55                     ".pushsection __bug_table,\"aw\"\n"                \
  56                     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"   \
  57                     "\t.word %c0"        "\t# bug_entry::flags\n"      \
  58                     "\t.org 2b+%c1\n"                                  \
  59                     ".popsection"                                      \
  60                     : : "i" (flags),                                   \
  61                         "i" (sizeof(struct bug_entry)));               \
  62} while (0)
  63
  64#endif /* CONFIG_DEBUG_BUGVERBOSE */
  65
  66#else
  67
  68#define _BUG_FLAGS(ins, flags)  asm volatile(ins)
  69
  70#endif /* CONFIG_GENERIC_BUG */
  71
  72#define HAVE_ARCH_BUG
  73#define BUG()                                                   \
  74do {                                                            \
  75        _BUG_FLAGS(ASM_UD2, 0);                                 \
  76        unreachable();                                          \
  77} while (0)
  78
  79#define __WARN_FLAGS(flags)     _BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags))
  80
  81#include <asm-generic/bug.h>
  82
  83#endif /* _ASM_X86_BUG_H */
  84