[PATCH] uml: x86_64 fixes

This fixes some x86_64 bugs -

- maybe_map returns -1 on error instead of 0, which is interpreted as
  physical address 0

- removed an include of ipc.h, which isn't needed

- fixed the calculation of signal frame location

- the signal delivery code is now immune to the stack expansion check

- added a missing include

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/sys-x86_64/syscalls.c b/arch/um/sys-x86_64/syscalls.c
index 2a575ef..dd99146 100644
--- a/arch/um/sys-x86_64/syscalls.c
+++ b/arch/um/sys-x86_64/syscalls.c
@@ -44,6 +44,8 @@
 #ifdef CONFIG_MODE_SKAS
 extern int userspace_pid[];
 
+#include "skas_ptrace.h"
+
 long sys_modify_ldt_skas(int func, void *ptr, unsigned long bytecount)
 {
 	struct ptrace_ldt ldt;