commit b06d059108db9b0c46cba29cc174f60e129164f1

Author: Johannes Meixner <jsmeix@suse.com>

Date:   Tue Mar 9 14:40:59 2021 +0100

    Merge pull request #2580 from rear/jsmeix-load-nvram-module

    In etc/scripts/system-setup.d/41-load-special-modules.sh

    load the nvram kernel module if possible to make /dev/nvram appear

    because /dev/nvram should be there when installing GRUB,

    see https://github.com/rear/rear/issues/2554

    and include the nvram kernel module in the recovery system

    because nvram could be a module in particular on POWER architecture

    see https://github.com/rear/rear/issues/2554#issuecomment-764720180

diff --git a/usr/share/rear/build/GNU/Linux/400_copy_modules.sh b/usr/share/rear/build/GNU/Linux/400_copy_modules.sh

index d8d733d2..a0ca9084 100644

--- a/usr/share/rear/build/GNU/Linux/400_copy_modules.sh

+++ b/usr/share/rear/build/GNU/Linux/400_copy_modules.sh

@@ -116,8 +116,12 @@ for dummy in "once" ; do

     # As a way out of this dilemma we add the below listed modules no longer via conf/GNU/Linux.conf

     # but here after the user config files were sourced so that now the user can specify

     # MODULES=( 'moduleX' 'moduleY' ) in etc/rear/local.conf to get additional kernel modules

-    # included in the recovery system in addition to the ones via an empty MODULES=() setting:

-    MODULES+=( vfat

+    # included in the recovery system in addition to the ones via an empty MODULES=() setting.

+    # nvram could be a module in particular on POWER architecture,

+    # cf. https://github.com/rear/rear/issues/2554#issuecomment-764720180

+    # and https://github.com/rear/rear/pull/2580#issuecomment-791344794

+    MODULES+=( nvram

+               vfat

                nls_iso8859_1 nls_utf8 nls_cp437

                af_packet

                unix

diff --git a/usr/share/rear/finalize/Linux-ppc64le/660_install_grub2.sh b/usr/share/rear/finalize/Linux-ppc64le/660_install_grub2.sh

index 4c2698f3..0cb3ee41 100644

--- a/usr/share/rear/finalize/Linux-ppc64le/660_install_grub2.sh

+++ b/usr/share/rear/finalize/Linux-ppc64le/660_install_grub2.sh

@@ -104,9 +104,39 @@ fi

 # Do not update nvram when system is running in PowerNV mode (BareMetal).

 # grub2-install will fail if not run with the --no-nvram option on a PowerNV system,

 # see https://github.com/rear/rear/pull/1742

-grub2_install_option=""

+grub2_no_nvram_option=""

 if [[ $(awk '/platform/ {print $NF}' < /proc/cpuinfo) == PowerNV ]] ; then

-    grub2_install_option="--no-nvram"

+    grub2_no_nvram_option="--no-nvram"

+fi

+# Also do not update nvram when no character device node /dev/nvram exists.

+# On POWER architecture the nvram kernel driver could be also built as a kernel module

+# that gets loaded via etc/scripts/system-setup.d/41-load-special-modules.sh

+# but whether or not the nvram kernel driver will then create /dev/nvram

+# depends on whether or not the hardware platform supports nvram.

+# I <jsmeix@suse.de> asked on a SUSE internal mailing list

+# and got the following reply (excerpts):

+# ----------------------------------------------------------------

+# > I would like to know when /dev/nvram exists and when not.

+# > I assume /dev/nvram gets created as other device nodes

+# > by the kernel (probably together with udev).

+# > I would like to know under what conditions /dev/nvram

+# > gets created and when it is not created.

+# > It seems on PPC /dev/nvram usually exist but sometimes not.

+# In case of powerpc, it gets created by nvram driver

+# (nvram_module_init) whenever the powerpc platform driver

+# has ppc_md.nvram_size greater than zero in it's machine

+# description structure.

+# How exactly ppc_md.nvram_size gets gets populated by platform

+# code depends on the platform, e.g. on most modern systems

+# it gets populated from 'nvram' device tree node

+# (and only if such node has #bytes > 0).

+# ----------------------------------------------------------------

+# So /dev/nvram may not exist regardless that the nvram kernel driver is there

+# and then grub2-install must be called with the '--no-nvram' option

+# because otherwise installing the bootloader fails

+# cf. https://github.com/rear/rear/issues/2554

+if ! test -c /dev/nvram ; then

+    grub2_no_nvram_option="--no-nvram"

 fi

 # When GRUB2_INSTALL_DEVICES is specified by the user

@@ -134,7 +164,7 @@ if test "$GRUB2_INSTALL_DEVICES" ; then

         else

             LogPrint "Installing GRUB2 on $grub2_install_device (specified in GRUB2_INSTALL_DEVICES)"

         fi

-        if ! chroot $TARGET_FS_ROOT /bin/bash --login -c "$grub_name-install $grub2_install_option $grub2_install_device" ; then

+        if ! chroot $TARGET_FS_ROOT /bin/bash --login -c "$grub_name-install $grub2_no_nvram_option $grub2_install_device" ; then

             LogPrintError "Failed to install GRUB2 on $grub2_install_device"

             grub2_install_failed="yes"

         fi

@@ -170,7 +200,7 @@ for part in $part_list ; do

         LogPrint "Found PPC PReP boot partition $part - installing GRUB2 there"

         # Erase the first 512 bytes of the PPC PReP boot partition:

         dd if=/dev/zero of=$part

-        if chroot $TARGET_FS_ROOT /bin/bash --login -c "$grub_name-install $grub2_install_option $part" ; then

+        if chroot $TARGET_FS_ROOT /bin/bash --login -c "$grub_name-install $grub2_no_nvram_option $part" ; then

             # In contrast to the above behaviour when GRUB2_INSTALL_DEVICES is specified

             # consider it here as a successful bootloader installation when GRUB2

             # got installed on at least one PPC PReP boot partition:

diff --git a/usr/share/rear/skel/default/etc/scripts/system-setup.d/41-load-special-modules.sh b/usr/share/rear/skel/default/etc/scripts/system-setup.d/41-load-special-modules.sh

index 9b0b3b8a..2e1d1912 100644

--- a/usr/share/rear/skel/default/etc/scripts/system-setup.d/41-load-special-modules.sh

+++ b/usr/share/rear/skel/default/etc/scripts/system-setup.d/41-load-special-modules.sh

@@ -1,6 +1,24 @@

-# some things are special

+# Special cases of kernel module loading.

-# XEN PV does not autoload some modules

-if [ -d /proc/xen ] ; then

-	modprobe xenblk

+# XEN PV does not autoload some modules:

+test -d /proc/xen && modprobe xenblk

+

+# On POWER architecture the nvram kernel driver may be no longer built into the kernel

+# but nowadays it could be also built as a kernel module that needs to be loaded

+# cf. https://github.com/rear/rear/issues/2554#issuecomment-764720180

+# because normally grub2-install gets called without the '--no-nvram' option

+# e.g. see finalize/Linux-ppc64le/620_install_grub2.sh

+# which is how grub2-install should be called when the hardware supports nvram.

+# Nothing to do when the character device node /dev/nvram exists

+# because then the nvram kernel driver is already there:

+if ! test -c /dev/nvram ; then

+    # Nothing can be done when there is no nvram kernel module.

+    # Suppress the possible 'modprobe -n nvram' error message like

+    # "modprobe: FATAL: Module nvram not found in directory /lib/modules/..."

+    # to avoid a possible "FATAL" false alarm message that would appear

+    # on the user's terminal during recovery system startup

+    # cf. https://github.com/rear/rear/pull/2537#issuecomment-741825046

+    # but when there is a nvram kernel module show possible 'modprobe nvram'

+    # (error) messages on the user's terminal during recovery system startup:

+    modprobe -n nvram 2>/dev/null && modprobe nvram

 fi