[PATCH] uml: x86_64 ptrace fixes

This patch fixes some missing ptrace bits on x86_64.  PTRACE_ARCH_PRCTL is
hooked up and implemented.  This required generalizing arch_prctl_skas
slightly to take a task_struct to modify.  Previously, it always operated on
current.

Reading and writing the debug registers is also enabled by un-ifdefing the
code that implements that.  It turns out that x86_64 is identical to i386, so
the same code can be used.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-um/ptrace-x86_64.h b/include/asm-um/ptrace-x86_64.h
index a927450..bf61d17 100644
--- a/include/asm-um/ptrace-x86_64.h
+++ b/include/asm-um/ptrace-x86_64.h
@@ -84,4 +84,7 @@
 extern void arch_switch_to_skas(struct task_struct *from,
 				struct task_struct *to);
 
+extern long arch_prctl_skas(struct task_struct *task, int code,
+			    unsigned long __user *addr);
+
 #endif