[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>

2 files changed, 28 insertions, 57 deletions

diff --git a/arch/sh64/kernel/ptrace.c b/arch/sh64/kernel/ptrace.c
index 71f2eec..cd22e94 100644
--- a/arch/sh64/kernel/ptrace.c
+++ b/arch/sh64/kernel/ptrace.c
@@ -28,6 +28,7 @@
 #include <linux/ptrace.h>
 #include <linux/user.h>
 #include <linux/signal.h>
+#include <linux/syscalls.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -121,61 +122,11 @@ put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 	return 0;
 }
 
-asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+
+long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
-	struct task_struct *child;
-	extern void poke_real_address_q(unsigned long long addr, unsigned long long data);
-#define WPC_DBRMODE 0x0d104008
-	static int first_call = 1;
 	int ret;
 
-	lock_kernel();
-
-	if (first_call) {
-		/* Set WPC.DBRMODE to 0.  This makes all debug events get
-		 * delivered through RESVEC, i.e. into the handlers in entry.S.
-		 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
-		 * would normally be left set to 1, which makes debug events get
-		 * delivered through DBRVEC, i.e. into the remote gdb's
-		 * handlers.  This prevents ptrace getting them, and confuses
-		 * the remote gdb.) */
-		printk("DBRMODE set to 0 to permit native debugging\n");
-		poke_real_address_q(WPC_DBRMODE, 0);
-		first_call = 0;
-	}
-
-	ret = -EPERM;
-	if (request == PTRACE_TRACEME) {
-		/* are we already being traced? */
-		if (current->ptrace & PT_PTRACED)
-			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)
-		goto out_tsk;
-
 	switch (request) {
 	/* when I and D space are separate, these will need to be fixed. */
 	case PTRACE_PEEKTEXT: /* read word at location addr. */
@@ -313,13 +264,33 @@ asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
-out_tsk:
-	put_task_struct(child);
-out:
-	unlock_kernel();
 	return ret;
 }
 
+asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
+{
+	extern void poke_real_address_q(unsigned long long addr, unsigned long long data);
+#define WPC_DBRMODE 0x0d104008
+	static int first_call = 1;
+
+	lock_kernel();
+	if (first_call) {
+		/* Set WPC.DBRMODE to 0.  This makes all debug events get
+		 * delivered through RESVEC, i.e. into the handlers in entry.S.
+		 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
+		 * would normally be left set to 1, which makes debug events get
+		 * delivered through DBRVEC, i.e. into the remote gdb's
+		 * handlers.  This prevents ptrace getting them, and confuses
+		 * the remote gdb.) */
+		printk("DBRMODE set to 0 to permit native debugging\n");
+		poke_real_address_q(WPC_DBRMODE, 0);
+		first_call = 0;
+	}
+	unlock_kernel();
+
+	return sys_ptrace(request, pid, addr, data);
+}
+
 asmlinkage void syscall_trace(void)
 {
 	struct task_struct *tsk = current;
diff --git a/arch/sh64/kernel/syscalls.S b/arch/sh64/kernel/syscalls.S
index a3d0378..c0079d5 100644
--- a/arch/sh64/kernel/syscalls.S
+++ b/arch/sh64/kernel/syscalls.S
@@ -46,7 +46,7 @@ sys_call_table:
 	.long sys_setuid16
 	.long sys_getuid16
 	.long sys_stime			/* 25 */
-	.long sys_ptrace
+	.long sh64_ptrace
 	.long sys_alarm
 	.long sys_fstat
 	.long sys_pause