[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>

arch/um/kernel/skas/uaccess.c

@@ -29,9 +29,12 @@ static unsigned long maybe_map(unsigned long virt, int is_write)
 	if(IS_ERR(phys) || (is_write && !pte_write(pte))){
 		err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
 		if(err)
-			return(0);
+			return(-1UL);
 		phys = um_virt_to_phys(current, virt, NULL);
 	}
+        if(IS_ERR(phys))
+                phys = (void *) -1;
+
 	return((unsigned long) phys);
 }
 
@@ -42,7 +45,7 @@ static int do_op(unsigned long addr, int len, int is_write,
 	int n;
 
 	addr = maybe_map(addr, is_write);
-	if(addr == -1)
+	if(addr == -1UL)
 		return(-1);
 
 	page = phys_to_page(addr);

arch/um/kernel/syscall_kern.c

@@ -17,7 +17,6 @@
 #include "linux/utime.h"
 #include "asm/mman.h"
 #include "asm/uaccess.h"
-#include "asm/ipc.h"
 #include "kern_util.h"
 #include "user_util.h"
 #include "sysdep/syscalls.h"

arch/um/kernel/trap_kern.c

@@ -48,7 +48,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 		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;

arch/um/sys-x86_64/signal.c

@@ -168,7 +168,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
 
 	frame = (struct rt_sigframe __user *)
 		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;
-	frame -= 128;
+	((unsigned char *) frame) -= 128;
 
 	if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
 		goto out;

arch/um/sys-x86_64/syscalls.c

@@ -44,6 +44,8 @@ long sys_modify_ldt_tt(int func, void *ptr, unsigned long bytecount)
 #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;