[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>

1 files changed, 33 insertions, 27 deletions

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 664c669b1856..5236fdb17fcb 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -495,29 +495,34 @@ sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
  * sys32_execve() executes a new program after the asm stub has set
  * things up for us.  This should basically do what I want it to.
  */
-asmlinkage long
-sys32_execve(struct pt_regs regs)
+asmlinkage long sys32_execve(void)
 {
-        int error;
-        char * filename;
+        struct pt_regs *regs = task_pt_regs(current);
+        char *filename;
+        unsigned long result;
+        int rc;
 
-        filename = getname(compat_ptr(regs.orig_gpr2));
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
+        filename = getname(compat_ptr(regs->orig_gpr2));
+        if (IS_ERR(filename)) {
+                result = PTR_ERR(filename);
                 goto out;
-        error = compat_do_execve(filename, compat_ptr(regs.gprs[3]),
-                                 compat_ptr(regs.gprs[4]), &regs);
-        if (error == 0)
-        {
-                task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
-                task_unlock(current);
-                current->thread.fp_regs.fpc=0;
-                asm volatile("sfpc %0,0" : : "d" (0));
         }
+        rc = compat_do_execve(filename, compat_ptr(regs->gprs[3]),
+                              compat_ptr(regs->gprs[4]), regs);
+        if (rc) {
+                result = rc;
+                goto out_putname;
+        }
+        task_lock(current);
+        current->ptrace &= ~PT_DTRACE;
+        task_unlock(current);
+        current->thread.fp_regs.fpc=0;
+        asm volatile("sfpc %0,0" : : "d" (0));
+        result = regs->gprs[2];
+out_putname:
         putname(filename);
 out:
-        return error;
+        return result;
 }
 
 
@@ -918,19 +923,20 @@ asmlinkage long sys32_write(unsigned int fd, char __user * buf, size_t count)
         return sys_write(fd, buf, count);
 }
 
-asmlinkage long sys32_clone(struct pt_regs regs)
+asmlinkage long sys32_clone(void)
 {
-        unsigned long clone_flags;
-        unsigned long newsp;
+        struct pt_regs *regs = task_pt_regs(current);
+        unsigned long clone_flags;
+        unsigned long newsp;
         int __user *parent_tidptr, *child_tidptr;
 
-        clone_flags = regs.gprs[3] & 0xffffffffUL;
-        newsp = regs.orig_gpr2 & 0x7fffffffUL;
-        parent_tidptr = compat_ptr(regs.gprs[4]);
-        child_tidptr = compat_ptr(regs.gprs[5]);
-        if (!newsp)
-                newsp = regs.gprs[15];
-        return do_fork(clone_flags, newsp, &regs, 0,
+        clone_flags = regs->gprs[3] & 0xffffffffUL;
+        newsp = regs->orig_gpr2 & 0x7fffffffUL;
+        parent_tidptr = compat_ptr(regs->gprs[4]);
+        child_tidptr = compat_ptr(regs->gprs[5]);
+        if (!newsp)
+                newsp = regs->gprs[15];
+        return do_fork(clone_flags, newsp, regs, 0,
                        parent_tidptr, child_tidptr);
 }