alpha: take a bunch of syscalls into osf_sys.c

New helper: current_thread_info().  Allows to do a bunch of odd syscalls
in C. While we are at it, there had never been a reason to do
osf_getpriority() in assembler.  We also get "namespace"-aware (read:
consistent with getuid(2), etc.) behaviour from getx?id() syscalls now.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/alpha/kernel/osf_sys.c

@@ -1404,3 +1404,52 @@ SYSCALL_DEFINE3(osf_writev, unsigned long, fd,
 }
 
 #endif
+
+SYSCALL_DEFINE2(osf_getpriority, int, which, int, who)
+{
+	int prio = sys_getpriority(which, who);
+	if (prio >= 0) {
+		/* Return value is the unbiased priority, i.e. 20 - prio.
+		   This does result in negative return values, so signal
+		   no error */
+		force_successful_syscall_return();
+		prio = 20 - prio;
+	}
+	return prio;
+}
+
+SYSCALL_DEFINE0(getxuid)
+{
+	current_pt_regs()->r20 = sys_geteuid();
+	return sys_getuid();
+}
+
+SYSCALL_DEFINE0(getxgid)
+{
+	current_pt_regs()->r20 = sys_getegid();
+	return sys_getgid();
+}
+
+SYSCALL_DEFINE0(getxpid)
+{
+	current_pt_regs()->r20 = sys_getppid();
+	return sys_getpid();
+}
+
+SYSCALL_DEFINE0(alpha_pipe)
+{
+	int fd[2];
+	int res = do_pipe_flags(fd, 0);
+	if (!res) {
+		/* The return values are in $0 and $20.  */
+		current_pt_regs()->r20 = fd[1];
+		res = fd[0];
+	}
+	return res;
+}
+
+SYSCALL_DEFINE1(sethae, unsigned long, val)
+{
+	current_pt_regs()->hae = val;
+	return 0;
+}