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>

1 files changed, 22 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index dc0c49cfd90a..dd2c85f0bd8d 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/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);