[PATCH] uml: fix syscall table by including $(SUBARCH)'s one, for x86-64

Reuse asm-x86-64/unistd.h to build our syscall table, like x86-64 already
does.

Like for i386, we must add some #defines for all the (right!) changes UML does
to x86-64 syscall table.

Note: I noted a bogus:
	[ __NR_sched_yield ] = (syscall_handler_t *) yield,

while doing this patch (which could only be a workaround for some strange bug,
but I would ignore this possibility).  I'm changing this without notice.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/sys-x86_64/syscall_table.c

@@ -0,0 +1,59 @@
+/* System call table for UML/x86-64, copied from arch/x86_64/kernel/syscall.c
+ * with some changes for UML. */
+
+#include <linux/linkage.h>
+#include <linux/sys.h>
+#include <linux/cache.h>
+#include <linux/config.h>
+
+#define __NO_STUBS
+
+/* Below you can see, in terms of #define's, the differences between the x86-64
+ * and the UML syscall table. */
+
+/* Not going to be implemented by UML, since we have no hardware. */
+#define stub_iopl sys_ni_syscall
+#define sys_ioperm sys_ni_syscall
+
+/* The UML TLS problem. Note that x86_64 does not implement this, so the below
+ * is needed only for the ia32 compatibility. */
+/*#define sys_set_thread_area sys_ni_syscall
+#define sys_get_thread_area sys_ni_syscall*/
+
+/* For __NR_time. The x86-64 name hopefully will change from sys_time64 to
+ * sys_time (since the current situation is bogus). I've sent a patch to cleanup
+ * this. Remove below the obsoleted line. */
+#define sys_time64 um_time
+#define sys_time um_time
+
+/* On UML we call it this way ("old" means it's not mmap2) */
+#define sys_mmap old_mmap
+/* On x86-64 sys_uname is actually sys_newuname plus a compatibility trick.
+ * See arch/x86_64/kernel/sys_x86_64.c */
+#define sys_uname sys_uname64
+
+#define stub_clone sys_clone
+#define stub_fork sys_fork
+#define stub_vfork sys_vfork
+#define stub_execve sys_execve
+#define stub_rt_sigsuspend sys_rt_sigsuspend
+#define stub_sigaltstack sys_sigaltstack
+#define stub_rt_sigreturn sys_rt_sigreturn
+
+#define __SYSCALL(nr, sym) extern asmlinkage void sym(void) ;
+#undef _ASM_X86_64_UNISTD_H_
+#include <asm-x86_64/unistd.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, sym) [ nr ] = sym,
+#undef _ASM_X86_64_UNISTD_H_
+
+typedef void (*sys_call_ptr_t)(void);
+
+extern void sys_ni_syscall(void);
+
+sys_call_ptr_t sys_call_table[__NR_syscall_max+1] __cacheline_aligned = {
+	/* Smells like a like a compiler bug -- it doesn't work when the & below is removed. */
+	[0 ... __NR_syscall_max] = &sys_ni_syscall,
+#include <asm-x86_64/unistd.h>
+};