Currently the build of insn_sanity against musl libc fails:

          HOSTCC  arch/x86/tools/insn_sanity
        In file included from arch/x86/tools/insn_sanity.c:17:
        In file included from ./tools/arch/x86/include/asm/insn.h:10:
        In file included from /usr/include/asm/byteorder.h:5:
        In file included from ./include/uapi/linux/byteorder/little_endian.h:14:
        ./include/uapi/linux/swab.h:48:15: error: unknown type name
        '__attribute_const__'
        ./include/uapi/linux/swab.h:48:15: error: unknown type name
        '__attribute_const__'
           48 | static inline __attribute_const__ __u16 __fswab16(__u16 val)
              |               ^
        ./include/uapi/linux/swab.h:48:8: error: 'inline' can only appear on functions
           48 | static inline __attribute_const__ __u16 __fswab16(__u16 val)
              |        ^
        ...

__attribute_const__ is an internal kernel symbol and is stripped from
the UAPI headers during installation (see scripts/headers_install.sh).
The error does not happen on glibc as by chance that provides its own,
compatible definition of __attribute_const__.
The usage of the unprocess UAPI headers for insn_santity was an
unintended side-effect of commit a76108d05ee1 ("x86/entry/vdso: Move
vdso2c to arch/x86/tools") and is not necessary.

Only use the unprocessed UAPI headers for vdso2c, like before.

The usage of the unprocessed UAPI headers should be removed
completely, but that will require a bit more changes,
not suitable for this late in the cycle.

Reported-by: Theron York <theron.york@cloudnuke.org>
Closes: https://lore.kernel.org/lkml/399bf58e-1c91-4c3c-a3df-dae08a891b55@cloudnuke.org/
Fixes: a76108d05ee1 ("x86/entry/vdso: Move vdso2c to arch/x86/tools")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 arch/x86/tools/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/tools/Makefile b/arch/x86/tools/Makefile
index 39a183fffd04..afd967bc4051 100644
--- a/arch/x86/tools/Makefile
+++ b/arch/x86/tools/Makefile
@@ -38,8 +38,9 @@ $(obj)/insn_decoder_test.o: $(srctree)/tools/arch/x86/lib/insn.c $(srctree)/tool
 
 $(obj)/insn_sanity.o: $(srctree)/tools/arch/x86/lib/insn.c $(srctree)/tools/arch/x86/lib/inat.c $(srctree)/tools/arch/x86/include/asm/inat_types.h $(srctree)/tools/arch/x86/include/asm/inat.h $(srctree)/tools/arch/x86/include/asm/insn.h $(objtree)/arch/x86/lib/inat-tables.c
 
-HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi \
-		    -I$(srctree)/arch/$(SUBARCH)/include/uapi
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include
+
+HOSTCFLAGS_vdso2c.o := -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
 
 hostprogs	+= relocs vdso2c
 relocs-objs	:= relocs_32.o relocs_64.o relocs_common.o

---
base-commit: f5e5d3509bffb95c6648eb9795f7f236852ae62d
change-id: 20260530-x86-tools-build-fix2-5365fbfada64

Best regards,
--  
Thomas Weißschuh <linux@weissschuh.net>