1 files changed, 89 insertions, 0 deletions
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
new file mode 100644
index 000000000..a3ec87d19
--- /dev/null
+++ b/arch/x86/include/asm/bug.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_BUG_H
+#define _ASM_X86_BUG_H
+
+#include <linux/stringify.h>
+#include <linux/instrumentation.h>
+#include <linux/objtool.h>
+
+/*
+ * Despite that some emulators terminate on UD2, we use it for WARN().
+ */
+#define ASM_UD2		".byte 0x0f, 0x0b"
+#define INSN_UD2	0x0b0f
+#define LEN_UD2		2
+
+#ifdef CONFIG_GENERIC_BUG
+
+#ifdef CONFIG_X86_32
+# define __BUG_REL(val)	".long " __stringify(val)
+#else
+# define __BUG_REL(val)	".long " __stringify(val) " - ."
+#endif
+
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#define _BUG_FLAGS(ins, flags, extra)					\
+do {									\
+	asm_inline volatile("1:\t" ins "\n"				\
+		     ".pushsection __bug_table,\"aw\"\n"		\
+		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
+		     "\t"  __BUG_REL(%c0) "\t# bug_entry::file\n"	\
+		     "\t.word %c1"        "\t# bug_entry::line\n"	\
+		     "\t.word %c2"        "\t# bug_entry::flags\n"	\
+		     "\t.org 2b+%c3\n"					\
+		     ".popsection\n"					\
+		     extra						\
+		     : : "i" (__FILE__), "i" (__LINE__),		\
+			 "i" (flags),					\
+			 "i" (sizeof(struct bug_entry)));		\
+} while (0)
+
+#else /* !CONFIG_DEBUG_BUGVERBOSE */
+
+#define _BUG_FLAGS(ins, flags, extra)					\
+do {									\
+	asm_inline volatile("1:\t" ins "\n"				\
+		     ".pushsection __bug_table,\"aw\"\n"		\
+		     "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n"	\
+		     "\t.word %c0"        "\t# bug_entry::flags\n"	\
+		     "\t.org 2b+%c1\n"					\
+		     ".popsection\n"					\
+		     extra						\
+		     : : "i" (flags),					\
+			 "i" (sizeof(struct bug_entry)));		\
+} while (0)
+
+#endif /* CONFIG_DEBUG_BUGVERBOSE */
+
+#else
+
+#define _BUG_FLAGS(ins, flags, extra)  asm volatile(ins)
+
+#endif /* CONFIG_GENERIC_BUG */
+
+#define HAVE_ARCH_BUG
+#define BUG()							\
+do {								\
+	instrumentation_begin();				\
+	_BUG_FLAGS(ASM_UD2, 0, "");				\
+	__builtin_unreachable();				\
+} while (0)
+
+/*
+ * This instrumentation_begin() is strictly speaking incorrect; but it
+ * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
+ * were to trigger, we'd rather wreck the machine in an attempt to get the
+ * message out than not know about it.
+ */
+#define __WARN_FLAGS(flags)					\
+do {								\
+	__auto_type __flags = BUGFLAG_WARNING|(flags);		\
+	instrumentation_begin();				\
+	_BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE);		\
+	instrumentation_end();					\
+} while (0)
+
+#include <asm-generic/bug.h>
+
+#endif /* _ASM_X86_BUG_H */