[PATCH] consolidate sys_ptrace()

The sys_ptrace boilerplate code (everything outside the big switch
statement for the arch-specific requests) is shared by most architectures.
This patch moves it to kernel/ptrace.c and leaves the arch-specific code as
arch_ptrace.

Some architectures have a too different ptrace so we have to exclude them.
They continue to keep their implementations.  For sh64 I had to add a
sh64_ptrace wrapper because it does some initialization on the first call.
For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but
SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-By: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/arm26/kernel/ptrace.c

@@ -546,7 +546,7 @@ static int ptrace_setfpregs(struct task_struct *tsk, void *ufp)
 			      sizeof(struct user_fp)) ? -EFAULT : 0;
 }
 
-static int do_ptrace(int request, struct task_struct *child, long addr, long data)
+long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
 	unsigned long tmp;
 	int ret;
@@ -665,53 +665,6 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat
 	return ret;
 }
 
-asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
-{
-	struct task_struct *child;
-	int ret;
-
-	lock_kernel();
-	ret = -EPERM;
-	if (request == PTRACE_TRACEME) {
-		/* are we already being traced? */
-		if (current->ptrace & PT_PTRACED)
-			goto out;
-		ret = security_ptrace(current->parent, current);
-		if (ret)
-			goto out;
-		/* set the ptrace bit in the process flags. */
-		current->ptrace |= PT_PTRACED;
-		ret = 0;
-		goto out;
-	}
-	ret = -ESRCH;
-	read_lock(&tasklist_lock);
-	child = find_task_by_pid(pid);
-	if (child)
-		get_task_struct(child);
-	read_unlock(&tasklist_lock);
-	if (!child)
-		goto out;
-
-	ret = -EPERM;
-	if (pid == 1)		/* you may not mess with init */
-		goto out_tsk;
-
-	if (request == PTRACE_ATTACH) {
-		ret = ptrace_attach(child);
-		goto out_tsk;
-	}
-	ret = ptrace_check_attach(child, request == PTRACE_KILL);
-	if (ret == 0)
-		ret = do_ptrace(request, child, addr, data);
-
-out_tsk:
-	put_task_struct(child);
-out:
-	unlock_kernel();
-	return ret;
-}
-
 asmlinkage void syscall_trace(int why, struct pt_regs *regs)
 {
 	unsigned long ip;