tools headers: Update the arch/x86/lib/memset_64.S copy with the kernel sources

To pick up the changes in:

  2981557cb0 x86,kcfi: Fix EXPORT_SYMBOL vs kCFI

That required adding a copy of include/linux/cfi_types.h and its checking
in tools/perf/check-headers.h.

Addressing this perf tools build warning:

  Warning: Kernel ABI header differences:
    diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S

Please see tools/include/uapi/README for further details.

Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: x86@kernel.org
Link: https://lore.kernel.org/r/20250410001125.391820-11-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/arch/x86/lib/memset_64.S

@@ -3,6 +3,7 @@
 
 #include <linux/export.h>
 #include <linux/linkage.h>
+#include <linux/cfi_types.h>
 #include <asm/cpufeatures.h>
 #include <asm/alternative.h>
 
@@ -28,7 +29,7 @@
  * only for the return value that is the same as the source input,
  * which the compiler could/should do much better anyway.
  */
-SYM_FUNC_START(__memset)
+SYM_TYPED_FUNC_START(__memset)
 	ALTERNATIVE "jmp memset_orig", "", X86_FEATURE_FSRS
 
 	movq %rdi,%r9

tools/include/linux/cfi_types.h

@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Clang Control Flow Integrity (CFI) type definitions.
+ */
+#ifndef _LINUX_CFI_TYPES_H
+#define _LINUX_CFI_TYPES_H
+
+#ifdef __ASSEMBLY__
+#include <linux/linkage.h>
+
+#ifdef CONFIG_CFI_CLANG
+/*
+ * Use the __kcfi_typeid_<function> type identifier symbol to
+ * annotate indirectly called assembly functions. The compiler emits
+ * these symbols for all address-taken function declarations in C
+ * code.
+ */
+#ifndef __CFI_TYPE
+#define __CFI_TYPE(name)				\
+	.4byte __kcfi_typeid_##name
+#endif
+
+#define SYM_TYPED_ENTRY(name, linkage, align...)	\
+	linkage(name) ASM_NL				\
+	align ASM_NL					\
+	__CFI_TYPE(name) ASM_NL				\
+	name:
+
+#define SYM_TYPED_START(name, linkage, align...)	\
+	SYM_TYPED_ENTRY(name, linkage, align)
+
+#else /* CONFIG_CFI_CLANG */
+
+#define SYM_TYPED_START(name, linkage, align...)	\
+	SYM_START(name, linkage, align)
+
+#endif /* CONFIG_CFI_CLANG */
+
+#ifndef SYM_TYPED_FUNC_START
+#define SYM_TYPED_FUNC_START(name) 			\
+	SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* _LINUX_CFI_TYPES_H */

tools/perf/check-headers.sh

@@ -20,6 +20,7 @@ FILES=(
   "include/uapi/linux/stat.h"
   "include/linux/bits.h"
   "include/vdso/bits.h"
+  "include/linux/cfi_types.h"
   "include/linux/const.h"
   "include/vdso/const.h"
   "include/vdso/unaligned.h"