x86/signals: ia32_signal.c: add __user casts to fix sparse warnings

Fix the following sparse warnings by adding appropriate __user
casts and annotations:

ia32_signal.c:165:38: warning: incorrect type in argument 1 (different address spaces)
ia32_signal.c:165:38: expected struct sigaltstack const [noderef] [usertype] <asn:1>*<noident>
ia32_signal.c:165:38: got struct sigaltstack *
[...]

Signed-off-by: Mathias Krause <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/ia32/ia32_signal.c

···
 	}
 	seg = get_fs();
 	set_fs(KERNEL_DS);
-	ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->sp);
+	ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
+			     (stack_t __force __user *) &uoss, regs->sp);
 	set_fs(seg);
 	if (ret >= 0 && uoss_ptr)  {
 		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)))
···
  */
 static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 				 size_t frame_size,
-				 void **fpstate)
+				 void __user **fpstate)
 {
 	unsigned long sp;
 
···
 
 	if (used_math()) {
 		sp = sp - sig_xstate_ia32_size;
-		*fpstate = (struct _fpstate_ia32 *) sp;
+		*fpstate = (struct _fpstate_ia32 __user *) sp;
 		if (save_i387_xstate_ia32(*fpstate) < 0)
 			return (void __user *) -1L;
 	}
···
 		 * These are actually not used anymore, but left because some
 		 * gdb versions depend on them as a marker.
 		 */
-		put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
+		put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
 	} put_user_catch(err);
 
 	if (err)
···
 		 * Not actually used anymore, but left because some gdb
 		 * versions need it.
 		 */
-		put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
+		put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
 	} put_user_catch(err);
 
 	if (err)