x32: If configured, add x32 system calls to system call tables

If CONFIG_X86_X32_ABI is defined, add the x32 system calls to the
system call tables.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/asm-offsets_64.c

@@ -2,7 +2,11 @@
 
 #define __SYSCALL_64(nr, sym, compat) [nr] = 1,
 #define __SYSCALL_COMMON(nr, sym, compat) [nr] = 1,
-#define __SYSCALL_X32(nr, sym, compat) /* Not yet */
+#ifdef CONFIG_X86_X32_ABI
+# define __SYSCALL_X32(nr, sym, compat) [nr] = 1,
+#else
+# define __SYSCALL_X32(nr, sym, compat) /* nothing */
+#endif
 static char syscalls_64[] = {
 #include <asm/syscalls_64.h>
 };

arch/x86/kernel/syscall_64.c

@@ -6,7 +6,12 @@
 #include <asm/asm-offsets.h>
 
 #define __SYSCALL_COMMON(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
-#define __SYSCALL_X32(nr, sym, compat) /* Not yet */
+
+#ifdef CONFIG_X86_X32_ABI
+# define __SYSCALL_X32(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
+#else
+# define __SYSCALL_X32(nr, sym, compat) /* nothing */
+#endif
 
 #define __SYSCALL_64(nr, sym, compat) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_64.h>