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Commit 92019efc authored by Hari Bathini's avatar Hari Bathini Committed by Linus Torvalds
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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: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: default avatarMichael 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11550dc0

Documentation/powerpc/firmware-assisted-dump.txt

+15 −8
Original line number Diff line number Diff line
@@ -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:

------------