powerpc/fadump: update documentation about crashkernel parameter reuse

As we are reusing crashkernel parameter instead of fadump_reserve_mem
parameter to specify the memory to reserve for fadump's crash kernel,
update the documentation accordingly.

Link: http://lkml.kernel.org/r/149035347559.6881.14224829694291758581.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hari Bathini 2017-05-08 15:56:31 -07:00 committed by Linus Torvalds
parent 11550dc0a0
commit 92019efc6c

View File

@ -55,10 +55,14 @@ as follows:
booted with restricted memory. By default, the boot memory
size will be the larger of 5% of system RAM or 256MB.
Alternatively, user can also specify boot memory size
through boot parameter 'fadump_reserve_mem=' which will
override the default calculated size. Use this option
if default boot memory size is not sufficient for second
kernel to boot successfully.
through boot parameter 'crashkernel=' which will override
the default calculated size. Use this option if default
boot memory size is not sufficient for second kernel to
boot successfully. For syntax of crashkernel= parameter,
refer to Documentation/kdump/kdump.txt. If any offset is
provided in crashkernel= parameter, it will be ignored
as fadump reserves memory at end of RAM for boot memory
dump preservation in case of a crash.
-- After the low memory (boot memory) area has been saved, the
firmware will reset PCI and other hardware state. It will
@ -158,13 +162,16 @@ How to enable firmware-assisted dump (fadump):
1. Set config option CONFIG_FA_DUMP=y and build kernel.
2. Boot into linux kernel with 'fadump=on' kernel cmdline option.
3. Optionally, user can also set 'fadump_reserve_mem=' kernel cmdline
3. Optionally, user can also set 'crashkernel=' kernel cmdline
to specify size of the memory to reserve for boot memory dump
preservation.
NOTE: If firmware-assisted dump fails to reserve memory then it will
fallback to existing kdump mechanism if 'crashkernel=' option
is set at kernel cmdline.
NOTE: 1. 'fadump_reserve_mem=' parameter has been deprecated. Instead
use 'crashkernel=' to specify size of the memory to reserve
for boot memory dump preservation.
2. If firmware-assisted dump fails to reserve memory then it
will fallback to existing kdump mechanism if 'crashkernel='
option is set at kernel cmdline.
Sysfs/debugfs files:
------------