powerpc/fadump: Do not allow hot-remove memory from fadump reserved area.
commitfc090081d76a5d8acb4b78864ad74147e83ada6e
authorMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Mon, 20 Aug 2018 08:17:32 +0000 (20 13:47 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 12 Feb 2019 18:47:16 +0000 (12 19:47 +0100)
tree9ad5d5a6c2f7e650b36dd8c0bad64ab00c2cb1ea
parent84a4572bf2779118b5586a442c5efad9726d92c3
powerpc/fadump: Do not allow hot-remove memory from fadump reserved area.

[ Upstream commit 0db6896ff6332ba694f1e61b93ae3b2640317633 ]

For fadump to work successfully there should not be any holes in reserved
memory ranges where kernel has asked firmware to move the content of old
kernel memory in event of crash. Now that fadump uses CMA for reserved
area, this memory area is now not protected from hot-remove operations
unless it is cma allocated. Hence, fadump service can fail to re-register
after the hot-remove operation, if hot-removed memory belongs to fadump
reserved region. To avoid this make sure that memory from fadump reserved
area is not hot-removable if fadump is registered.

However, if user still wants to remove that memory, he can do so by
manually stopping fadump service before hot-remove operation.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/powerpc/include/asm/fadump.h
arch/powerpc/kernel/fadump.c
arch/powerpc/platforms/pseries/hotplug-memory.c