powerpc/pseries: Call ibm,os-term if the ibm,extended-os-term is present

We have had issues in the past with ibm,os-term initiating shutdown of a
partition. This is confusing to the user, especially if panic_timeout is
non zero.

The temporary fix was to avoid calling ibm,os-term if a panic_timeout was set
and since we set it on every boot we basically never call ibm,os-term.

An extended version of ibm,os-term has since been implemented which gives us
the behaviour we want:

  "When the platform supports extended ibm,os-term behavior, the return to the
  RTAS will always occur unless there is a kernel assisted dump active as
  initiated by an ibm,configure-kernel-dump call."

This patch checks for the ibm,extended-os-term property and calls ibm,os-term
if it exists.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/rtas.c

@@ -691,10 +691,14 @@ void rtas_os_term(char *str)
 {
 	int status;
 
-	if (panic_timeout)
-		return;
-
-	if (RTAS_UNKNOWN_SERVICE == rtas_token("ibm,os-term"))
+	/*
+	 * Firmware with the ibm,extended-os-term property is guaranteed
+	 * to always return from an ibm,os-term call. Earlier versions without
+	 * this property may terminate the partition which we want to avoid
+	 * since it interferes with panic_timeout.
+	 */
+	if (RTAS_UNKNOWN_SERVICE == rtas_token("ibm,os-term") ||
+	    RTAS_UNKNOWN_SERVICE == rtas_token("ibm,extended-os-term"))
 		return;
 
 	snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
@@ -705,8 +709,7 @@ void rtas_os_term(char *str)
 	} while (rtas_busy_delay(status));
 
 	if (status != 0)
-		printk(KERN_EMERG "ibm,os-term call failed %d\n",
-			       status);
+		printk(KERN_EMERG "ibm,os-term call failed %d\n", status);
 }
 
 static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE;