PTRACE_POKEDATA consolidation

Identical implementations of PTRACE_POKEDATA go into generic_ptrace_pokedata()
function.

AFAICS, fix bug on xtensa where successful PTRACE_POKEDATA will nevertheless
return EPERM.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 28afff4..f4503ca 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -314,10 +314,7 @@
 		/* Remove high order bit from address (only for 31 bit). */
 		addr &= PSW_ADDR_INSN;
 		/* write the word at location addr. */
-		copied = access_process_vm(child, addr, &data, sizeof(data),1);
-		if (copied != sizeof(data))
-			return -EIO;
-		return 0;
+		return generic_ptrace_pokedata(child, addr, data);
 
 	case PTRACE_POKEUSR:
 		/* write the word at location addr in the USER area */