# SPDX-License-Identifier: LGPL-2.1+
#
# Copyright (c) 2021 Valve.
#
# Code by Guilherme G. Piccoli <gpiccoli@igalia.com>
#
#
# ###########################################################################
# ############################ SteamOS Kdump ##############################
# ###########################################################################
#
# This is the first version of SteamOS Kdump infrastructure. The goal is to
# collect data whenever a kernel crash is detected. There is a lightweight
# collection, that only grabs dmesg, and a more complete setting to grab the
# whole (compressed) vmcore. The tunnings are available at /etc/default/kdump.
#
# Also, the infrastructure is able to configure and save pstore-RAM logs.
#
# After installation and a reboot, things should be all set EXCEPT for GRUB
# config - please check the CAVEATS/INSTRUCTIONS section below. Notice the
# package is under active development, this version should still be considered
# a kind of "Proof Of Concept" - improvements are expected in the near future.
# Thanks for testing!!!
#
#
# CAVEATS / INSTRUCTIONS
# ###########################################################################
# (a) For now, we don't automatically edit any GRUB config, so the minimum
# necessary action after installing this package is to add "crashkernel=160M"
# to your GRUB config in order subsequent boots pick this setting and do reserve
# the memory, or else kdump cannot work. The memory amount was empirically
# determined - 128M wasn't enough and 144M is unstable, so 160M seems good enough.
# If you prefer to rely on pstore-RAM, no GRUB setting should be required; this
# is currently the default (see /etc/default/kdump).
#
# (b) It requires (obviously) a RW rootfs - we've used tune2fs in order to make
# it read-write, since it's RO by default. Also, we assume the nvme partition
# scheme is default across all versions and didn't change with new updates
# for example - kdump relies in mounting partitions, etc.
#
# (c) Due to a post-transaction hook executed by libalpm (90-dracut-install.hook),
# unfortunately after installing the kdump-steamos package *all* initramfs images
# are recreated - this is not necessary, we're thinking on how to prevent that,
# but for now be prepared: the installation take some (long) minutes due to that ={
#
# (d) Unfortunately makedumpfile from Arch Linux is not available on official
# repos, only in AUR. So, we're hereby _packing the binary_ with all the scripts,
# which is a temporary workaround and should be resolved later - already started
# to "lobby" for package inclusion in the official channels:
# https://aur.archlinux.org/packages/makedumpfile/#comment-843853
#
#
# TODOs (for now - we expect to have more after some testing by the colleagues)
#
# (1) We'd like to be able to automatically edit GRUB and recreate its config
# file - after some future discussion on the proper parameters, this is expected
# to be added to the package.
#
# (2) Hopefully we can fix/prevent the unnecessary re-creation of all initramfs
# images - it happens due to our pkg installing files on /usr/lib/dracut/modules.d
# which is a trigger for this initramfs recreation.
#
# (3) We have a "fragile" way of determining a mount point required for kdump;
# this is something to improve in order to make the kdump more reliable.
#
# (4) Add a more reliable reboot mechanism - we had seen issues with "reboot -f"
# in the past and relying in sysrq reboot as a quirk managed to be a safe option,
# so this is something to think about here. Should be easy to implement.
#
# (5) Maybe a good idea would be to allow creating the minimum image for any
# specified kernel, not only for the running one (which is what we do now).
# Low-priority idea, easy to implement.
#
# (6) Pstore ramoops backend has some limitations that we're discussing with
# the kernel community - right now we can only collect ONE dmesg and its
# size is truncated on "record_size" bytes, not allowing a file split like
# efi-pstore; hopefully we can improve that.
#