[S390] System call cleanup.

Remove system call glue for sys_clone, sys_fork, sys_vfork, sys_execve,
sys_sigreturn, sys_rt_sigreturn and sys_sigaltstack. Call do_execve from
kernel_execve directly, move pt_regs to the right place and branch to
sysc_return to start the user space program. This removes the last
in-kernel system call.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 887a9881..80a54a0 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -255,9 +255,9 @@
 }
 
 asmlinkage long
-sys32_sigaltstack(const stack_t32 __user *uss, stack_t32 __user *uoss,
-							struct pt_regs *regs)
+sys32_sigaltstack(const stack_t32 __user *uss, stack_t32 __user *uoss)
 {
+	struct pt_regs *regs = task_pt_regs(current);
 	stack_t kss, koss;
 	unsigned long ss_sp;
 	int ret, err = 0;
@@ -344,8 +344,9 @@
 	return 0;
 }
 
-asmlinkage long sys32_sigreturn(struct pt_regs *regs)
+asmlinkage long sys32_sigreturn(void)
 {
+	struct pt_regs *regs = task_pt_regs(current);
 	sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 	sigset_t set;
 
@@ -370,8 +371,9 @@
 	return 0;
 }
 
-asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
+asmlinkage long sys32_rt_sigreturn(void)
 {
+	struct pt_regs *regs = task_pt_regs(current);
 	rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 	sigset_t set;
 	stack_t st;
@@ -407,8 +409,8 @@
 	return regs->gprs[2];
 
 badframe:
-        force_sig(SIGSEGV, current);
-        return 0;
+	force_sig(SIGSEGV, current);
+	return 0;
 }	
 
 /*