From 58cf055df47bb115e7c1533eec2a8f66639b80e3 Mon Sep 17 00:00:00 2001 From: Hari Bathini Date: Wed, 11 Sep 2019 20:26:16 +0530 Subject: [PATCH] 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/156821377195.5656.15840065629705958324.stgit@hbathini.in.ibm.com --- Documentation/powerpc/firmware-assisted-dump.rst | 9 +++++++++ 1 file changed, 9 insertions(+) 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: -----------------------