x32: Generate <asm/unistd_64_x32.h>

Generate macros for the *kernel* code to use to refer to x32 system
calls.  These have an __NR_x32_ prefix and do not include
__X32_SYSCALL_BIT.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/unistd.h

@@ -17,6 +17,7 @@
 # else
 
 #  include <asm/unistd_64.h>
+#  include <asm/unistd_64_x32.h>
 #  define __ARCH_WANT_COMPAT_SYS_TIME
 
 # endif

arch/x86/syscalls/Makefile

@@ -35,6 +35,11 @@ syshdr_abi_unistd_64 := common,64
 $(out)/unistd_64.h: $(syscall64) $(syshdr)
 	$(call if_changed,syshdr)
 
+syshdr_abi_unistd_64_x32 := x32
+syshdr_pfx_unistd_64_x32 := x32_
+$(out)/unistd_64_x32.h: $(syscall64) $(syshdr)
+	$(call if_changed,syshdr)
+
 $(out)/syscalls_32.h: $(syscall32) $(systbl)
 	$(call if_changed,systbl)
 $(out)/syscalls_64.h: $(syscall64) $(systbl)
@@ -42,7 +47,7 @@ $(out)/syscalls_64.h: $(syscall64) $(systbl)
 
 syshdr-y			+= unistd_32.h unistd_64.h unistd_x32.h
 syshdr-y			+= syscalls_32.h
-syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h
+syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h unistd_64_x32.h
 syshdr-$(CONFIG_X86_64)		+= syscalls_64.h
 
 targets	+= $(syshdr-y)