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authorHari Bathini <hbathini@linux.ibm.com>2019-09-11 17:56:16 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2019-09-13 17:04:45 +0300
commit58cf055df47bb115e7c1533eec2a8f66639b80e3 (patch)
tree8494849b22e8613fb47a3bbe8ad4c2d7387c3915 /Documentation/powerpc
parentbec53196adf4791d466adf0e339b61186c7b5283 (diff)
downloadlinux-58cf055df47bb115e7c1533eec2a8f66639b80e3.tar.xz
powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP
Kernel config option CONFIG_PRESERVE_FA_DUMP is introduced to ensure crash data, from previously crash'ed kernel, is preserved. Update documentation with this details. Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/156821377195.5656.15840065629705958324.stgit@hbathini.in.ibm.com
Diffstat (limited to 'Documentation/powerpc')
-rw-r--r--Documentation/powerpc/firmware-assisted-dump.rst9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index ab578ac64c09..08a9b5efcdc8 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -101,6 +101,15 @@ or later firmware versions on PowerNV (OPAL) platform.
Note that, OPAL firmware exports ibm,opal/dump node when
FADump is supported on PowerNV platform.
+On OPAL based machines, system first boots into an intermittent
+kernel (referred to as petitboot kernel) before booting into the
+capture kernel. This kernel would have minimal kernel and/or
+userspace support to process crash data. Such kernel needs to
+preserve previously crash'ed kernel's memory for the subsequent
+capture kernel boot to process this crash data. Kernel config
+option CONFIG_PRESERVE_FA_DUMP has to be enabled on such kernel
+to ensure that crash data is preserved to process later.
+
Implementation details:
-----------------------