[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 71f2eec00b99..cd22e9471316 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 a3d037805f1c..c0079d54c850 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