[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/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c
index 54e2ec3..5fca2c6 100644
--- a/arch/um/kernel/trap_kern.c
+++ b/arch/um/kernel/trap_kern.c
@@ -48,7 +48,7 @@
 		goto good_area;
 	else if(!(vma->vm_flags & VM_GROWSDOWN)) 
 		goto out;
-	else if(!ARCH_IS_STACKGROW(address))
+	else if(is_user && !ARCH_IS_STACKGROW(address))
 		goto out;
 	else if(expand_stack(vma, address)) 
 		goto out;