x86/bug: Add BUG_FORMAT basics

Opt-in to BUG_FORMAT for x86_64, adjust the BUGTABLE helper and for
now, just store NULL pointers.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.980264454@infradead.org

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index 27e3861cf984d1e8a26a87a397b957affc41ed81..5e63f9952a0c95301994aff691fcc3f7a991e1a4 100644 (file)
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -50,33 +50,44 @@
 #define __BUG_ENTRY_VERBOSE(file, line)
 #endif
 
-#define __BUG_ENTRY(file, line, flags)                                 \
+#if defined(CONFIG_X86_64) || defined(CONFIG_DEBUG_BUGVERBOSE_DETAILED)
+#define HAVE_ARCH_BUG_FORMAT
+#define __BUG_ENTRY_FORMAT(format)                                     \
+       "\t" __BUG_REL(format)  "\t# bug_entry::format\n"
+#else
+#define __BUG_ENTRY_FORMAT(format)
+#endif
+
+#define __BUG_ENTRY(format, file, line, flags)                         \
        __BUG_REL("1b")         "\t# bug_entry::bug_addr\n"             \
+       __BUG_ENTRY_FORMAT(format)                                      \
        __BUG_ENTRY_VERBOSE(file, line)                                 \
        "\t.word " flags        "\t# bug_entry::flags\n"
 
-#define _BUG_FLAGS_ASM(ins, file, line, flags, size, extra)            \
+#define _BUG_FLAGS_ASM(ins, format, file, line, flags, size, extra)    \
        "1:\t" ins "\n"                                                 \
        ".pushsection __bug_table,\"aw\"\n\t"                           \
        ANNOTATE_DATA_SPECIAL                                           \
        "2:\n\t"                                                        \
-       __BUG_ENTRY(file, line, flags)                                  \
+       __BUG_ENTRY(format, file, line, flags)                          \
        "\t.org 2b + " size "\n"                                        \
        ".popsection\n"                                                 \
        extra
 
 #define _BUG_FLAGS(cond_str, ins, flags, extra)                                \
 do {                                                                   \
-       asm_inline volatile(_BUG_FLAGS_ASM(ins, "%c0",                  \
-                                          "%c1", "%c2", "%c3", extra)  \
-                  : : "i" (WARN_CONDITION_STR(cond_str) __FILE__),     \
-                      "i" (__LINE__),                                  \
-                      "i" (flags),                                     \
-                      "i" (sizeof(struct bug_entry)));                 \
+       asm_inline volatile(_BUG_FLAGS_ASM(ins, "%c[fmt]", "%c[file]",  \
+                                          "%c[line]", "%c[fl]",        \
+                                          "%c[size]", extra)           \
+                  : : [fmt] "i" (NULL),                                \
+                      [file] "i" (WARN_CONDITION_STR(cond_str) __FILE__), \
+                      [line] "i" (__LINE__),                           \
+                      [fl] "i" (flags),                                \
+                      [size] "i" (sizeof(struct bug_entry)));          \
 } while (0)
 
 #define ARCH_WARN_ASM(file, line, flags, size)                         \
-       _BUG_FLAGS_ASM(ASM_UD2, file, line, flags, size, "")
+       _BUG_FLAGS_ASM(ASM_UD2, "0", file, line, flags, size, "")
 
 #else