powerpc: Do not call ppc_md.panic in fadump panic notifier

If fadump is not registered, and no other crash or debug handlers are
registered, the powerpc panic handler stops the guest before the
generic panic code can push out debug information to the console.

Currently, system reset injection causes the guest to silently stop.

Stop calling ppc_md.panic in the panic notifier. crash_fadump already
does rtas_os_term() to terminate the guest if fadump is registered.

Remove ppc_md.panic. Move fadump panic notifier into fadump code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/fadump.c

@@ -1446,6 +1446,25 @@ static void fadump_init_files(void)
 	return;
 }
 
+static int fadump_panic_event(struct notifier_block *this,
+			      unsigned long event, void *ptr)
+{
+	/*
+	 * If firmware-assisted dump has been registered then trigger
+	 * firmware-assisted dump and let firmware handle everything
+	 * else. If this returns, then fadump was not registered, so
+	 * go through the rest of the panic path.
+	 */
+	crash_fadump(NULL, ptr);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block fadump_panic_block = {
+	.notifier_call = fadump_panic_event,
+	.priority = INT_MIN /* may not return; must be done last */
+};
+
 /*
  * Prepare for firmware-assisted dump.
  */
@@ -1478,6 +1497,9 @@ int __init setup_fadump(void)
 		init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
 	fadump_init_files();
 
+	atomic_notifier_chain_register(&panic_notifier_list,
+					&fadump_panic_block);
+
 	return 1;
 }
 subsys_initcall(setup_fadump);

arch/powerpc/kernel/setup-common.c

@@ -704,30 +704,6 @@ int check_legacy_ioport(unsigned long base_port)
 }
 EXPORT_SYMBOL(check_legacy_ioport);
 
-static int ppc_panic_event(struct notifier_block *this,
-                             unsigned long event, void *ptr)
-{
-	/*
-	 * If firmware-assisted dump has been registered then trigger
-	 * firmware-assisted dump and let firmware handle everything else.
-	 */
-	crash_fadump(NULL, ptr);
-	ppc_md.panic(ptr);  /* May not return */
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block ppc_panic_block = {
-	.notifier_call = ppc_panic_event,
-	.priority = INT_MIN /* may not return; must be done last */
-};
-
-void __init setup_panic(void)
-{
-	if (!ppc_md.panic)
-		return;
-	atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
-}
-
 #ifdef CONFIG_CHECK_CACHE_COHERENCY
 /*
  * For platforms that have configurable cache-coherency.  This function
@@ -872,9 +848,6 @@ void __init setup_arch(char **cmdline_p)
 	/* Probe the machine type, establish ppc_md. */
 	probe_machine();
 
-	/* Setup panic notifier if requested by the platform. */
-	setup_panic();
-
 	/*
 	 * Configure ppc_md.power_save (ppc32 only, 64-bit machines do
 	 * it from their respective probe() function.