From 607451ce0aa9bdff590db4d087173edba6d7a29d Mon Sep 17 00:00:00 2001
From: Hari Bathini <hbathini@linux.ibm.com>
Date: Tue, 1 Feb 2022 16:23:05 +0530
Subject: [PATCH] powerpc/fadump: register for fadump as early as possible

References: bsc#1179439 ltc#190038
Patch-mainline: v5.18-rc1
Git-commit: 607451ce0aa9bdff590db4d087173edba6d7a29d

Crash recovery (fadump) is setup in the userspace by some service. This
service rebuilds initrd with dump capture capability, if it is not
already dump capture capable before proceeding to register for firmware
assisted dump (echo 1 > /sys/kernel/fadump/registered). But arming the
kernel with crash recovery support does not have to wait for userspace
configuration. So, register for fadump while setting it up itself. This
can at worst lead to a scenario, where /proc/vmcore is ready afer crash
but the initrd does not know how/where to offload it, which is always
better than not having a /proc/vmcore at all due to incomplete
configuration in the userspace at the time of crash.

Commit 0823c68b054b ("powerpc/fadump: re-register firmware-assisted dump
if already registered") ensures this change does not break userspace.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
[mpe: Reword comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220201105305.155511-1-hbathini@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/fadump.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index d03e488cfe9c..cf92f3fb17d2 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1637,9 +1637,11 @@ int __init setup_fadump(void)
 		if (fw_dump.ops->fadump_process(&fw_dump) < 0)
 			fadump_invalidate_release_mem();
 	}
-	/* Initialize the kernel dump memory structure for FAD registration. */
-	else if (fw_dump.reserve_dump_area_size)
+	/* Initialize the kernel dump memory structure and register with f/w */
+	else if (fw_dump.reserve_dump_area_size) {
 		fw_dump.ops->fadump_init_mem_struct(&fw_dump);
+		register_fadump();
+	}
 
 	/*
 	 * In case of panic, fadump is triggered via ppc_panic_event()
@@ -1651,7 +1653,12 @@ int __init setup_fadump(void)
 
 	return 1;
 }
-subsys_initcall(setup_fadump);
+/*
+ * Use subsys_initcall_sync() here because there is dependency with
+ * crash_save_vmcoreinfo_init(), which mush run first to ensure vmcoreinfo initialization
+ * is done before regisering with f/w.
+ */
+subsys_initcall_sync(setup_fadump);
 #else /* !CONFIG_PRESERVE_FA_DUMP */
 
 /* Scan the Firmware Assisted dump configuration details. */
-- 
2.34.1