[PATCH] powerpc/fadump: Unregister fadump on kexec down path.

[Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

Unregister fadump on kexec down path otherwise the fadump registration in
new kexec-ed kernel complains that fadump is already registered. This
makes new kernel to continue using fadump registered by previous kernel
which may lead to invalid vmcore generation. Hence this patch fixes this
issue by un-registering fadump in fadump_cleanup() which is called during
kexec path so that new kernel can register fadump with new valid values.

Fixes: b500afff11f6 ("fadump: Invalidate registration and release reserved memory for general use.")
Cc: stable@vger.kernel.org
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/fadump.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 8ceabef40d3d..07e8396d472b 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1180,6 +1180,9 @@ void fadump_cleanup(void)
 		init_fadump_mem_struct(&fdm,
 			be64_to_cpu(fdm_active->cpu_state_data.destination_address));
 		fadump_invalidate_dump(&fdm);
+	} else if (fw_dump.dump_registered) {
+		/* Un-register Firmware-assisted dump if it was registered. */
+		fadump_unregister_dump(&fdm);
 	}
 }