bcm4908: support "rootfs_data" on U-Boot devices

1. Create "rootfs_data" dynamicaly

U-Boot firmware images can contain only 2 UBI volumes: bootfs (container
with U-Boot + kernel + DTBs) and rootfs (e.g. squashfs). There is no way
to include "rootfs_data" UBI volume or make firmware file tell U-Boot to
create one.

For that reason "rootfs_data" needs to be created dynamically. Use
preinit script to handle that. Fire it right before "mount_root" one.

2. Relate "rootfs_data" to flashed firmware

As already explained flashing new firmware with U-Boot will do nothing
to the "rootfs_data". It could result in new firmware reusing old
"rootfs_data" overlay UBI volume and its file. Users expect a clean
state after flashing firmware (even if flashing the same one).

Solve that by reading flash counter of running firmware and storing it
in "rootfs_data" UBI volume. Every mismatch will result in wiping old
data.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki 2022-03-04 16:03:26 +01:00
parent 247eaa4416
commit 93259e8ca2
3 changed files with 122 additions and 13 deletions

View File

@ -0,0 +1,73 @@
# SPDX-License-Identifier: GPL-2.0-or-later OR BSD-2-Clause
FS_STATE_READY=2
# $(1): file to read from
# $(2): offset in bytes
get_hex_u32_le() {
dd if="$1" skip=$2 bs=1 count=4 2>/dev/null | hexdump -v -e '1/4 "%02x"'
}
# Setup /tmp/env.config to provide "metadata" UBI volume access
#
# It can be used with "fw_printenv -c /tmp/env.config"
bcm4908_pkgtb_setup_env_config() {
local size=$((0x$(get_hex_u32_le /dev/ubi0_1 4)))
dd if=/dev/ubi0_1 of=/tmp/env.head count=8 iflag=count_bytes
dd if=/dev/ubi0_1 of=/tmp/env.body skip=8 iflag=skip_bytes
printf "%s\t0x%x\t0x%x\t0x%x" "/tmp/env.body" 0x0 $size $size > /tmp/env.config
}
bcm4908_committed_image_seq() {
bcm4908_pkgtb_setup_env_config
commited="$(fw_printenv -n -c /tmp/env.config COMMITTED)"
[ -n "$commited" ] && {
seq=$(fw_printenv -n -c /tmp/env.config SEQ | cut -d ',' -f $commited)
[ -n "$seq" ] && {
echo $seq
return
}
}
echo "Failed to read COMMITED and SEQ from metadata1" >&2
}
# Make sure "rootfs_data" UBI volume matches currently flashed image
#
# On mismatch "rootfs_data" will be wiped and assigned
#
# $1: UBI volume of "rootfs_data" (e.g. ubi0_123)
bcm4908_verify_rootfs_data() {
local ubivol="$1"
local dir=/tmp/rootfs_data
local seq="$(bcm4908_committed_image_seq)"
[ -z "$seq" ] && return
mkdir $dir
if ! mount -t ubifs /dev/$ubivol $dir; then
echo "Failed to mount $ubivol UBI volume" >&2
rmdir $dir
return
fi
# Wipe rootfs_data if it doesn't belong to us
[ "$(readlink $dir/.openwrt-image-seq)" != "$seq" ] && {
echo "Removing \"rootfs_data\" content"
rm -rf $dir/..?* $dir/.[!.]* $dir/*
}
# If rootfs_data is clean (or was just wiped) claim it
[ -z "$(ls -A $dir)" ] && {
echo "Assigning \"rootfs_data\" to the current firmware"
# Claim this "rootfs_data"
ln -s $seq $dir/.openwrt-image-seq
# Mark it ready to avoid "mount_root" wiping it again
ln -s $FS_STATE_READY $dir/.fs_state
}
umount $dir
rmdir $dir
}

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@ -0,0 +1,35 @@
# SPDX-License-Identifier: GPL-2.0-or-later OR BSD-2-Clause
. /lib/functions/bcm4908.sh
rootfs_create() {
local blocks
blocks=$(cat /sys/class/ubi/ubi0/avail_eraseblocks)
[ -z "$blocks" ] && {
echo "Failed to read amount of available erase blocks" >&2
return
}
# Use 80% of remaining flash size for "rootfs_data"
ubimkvol /dev/ubi0 -n 20 -N rootfs_data --lebs $((blocks / 100 * 80))
mknod -m 0600 /dev/ubi0_20 c 252 21
bcm4908_verify_rootfs_data ubi0_20
}
rootfs_prepare() {
# Do nothing on CFE devices
ubinfo /dev/ubi0 -N metadata1 > /dev/null 2>&1 || exit 0
# Find UBI volume device (e.g. ubi0_123)
local ubivol="$(grep rootfs_data /sys/devices/virtual/ubi/ubi*/ubi*/name | sed -n 's/.*\(ubi\d*_\d*\).*/\1/p')"
if [ -n "$ubivol" ]; then
bcm4908_verify_rootfs_data $ubivol
else
echo "Creating \"rootfs_data\" UBI volume"
rootfs_create
fi
}
boot_hook_add preinit_main rootfs_prepare

View File

@ -1,6 +1,8 @@
# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
RAMFS_COPY_BIN="bcm4908img expr grep fdtget fw_printenv fw_setenv tr"
. /lib/functions/bcm4908.sh
RAMFS_COPY_BIN="bcm4908img expr grep ln fdtget fw_printenv fw_setenv readlink tr"
PART_NAME=firmware
@ -134,17 +136,7 @@ platform_pkgtb_get_image() {
}
}
platform_pkgtb_setup_env_config() {
local size=$((0x$(get_hex_u32_le /dev/ubi0_1 4)))
dd if=/dev/ubi0_1 of=/tmp/env.head count=8 iflag=count_bytes
dd if=/dev/ubi0_1 of=/tmp/env.body skip=8 iflag=skip_bytes
printf "%s\t0x%x\t0x%x\t0x%x" "/tmp/env.body" 0x0 $size $size > /tmp/env.config
}
platform_pkgtb_get_upgrade_index() {
platform_pkgtb_setup_env_config
case "$(fw_printenv -l /tmp -n -c /tmp/env.config COMMITTED)" in
1) echo 2;;
2) echo 1;;
@ -160,8 +152,6 @@ platform_pkgtb_commit() {
local seq2
local tmp
platform_pkgtb_setup_env_config
# Read current values
for valid in $(fw_printenv -l /tmp -n -c /tmp/env.config VALID | tr ',' ' '); do
case "$valid" in
@ -272,11 +262,20 @@ platform_check_image() {
# upgrade
#
platform_pkgtb_clean_rootfs_data() {
local ubidev=$(nand_find_ubi $CI_UBIPART)
local ubivol="$(nand_find_volume $ubidev rootfs_data)"
bcm4908_verify_rootfs_data "$ubivol"
}
platform_do_upgrade_pkgtb() {
local cmd="${2:-cat}"
local size
local idx bootfs_id rootfs_id
bcm4908_pkgtb_setup_env_config
idx=$(platform_pkgtb_get_upgrade_index)
case "$idx" in
1) bootfs_id=3; rootfs_id=4;;
@ -295,6 +294,8 @@ platform_do_upgrade_pkgtb() {
platform_pkgtb_commit $idx
CI_UBIPART="image"
platform_pkgtb_clean_rootfs_data
nand_do_upgrade_success
}