gk7205v200: capture a crash log across reboot with pstore/ramoops

br-ext-chip-goke/board/gk7205v200/gk7205v200.generic.config

@@ -2391,7 +2391,16 @@ CONFIG_SQUASHFS_FRAGMENT_CACHE_SIZE=1
 # CONFIG_QNX4FS_FS is not set
 # CONFIG_QNX6FS_FS is not set
 # CONFIG_ROMFS_FS is not set
-# CONFIG_PSTORE is not set
+CONFIG_PSTORE=y
+# Compression is a mandatory choice on this 4.9 kernel (it has no "none"); ZLIB
+# is its default and the only one whose workspace is preallocated at register
+# time, so it stays safe to compress from inside a panic. The others stay off.
+CONFIG_PSTORE_ZLIB_COMPRESS=y
+# CONFIG_PSTORE_LZO_COMPRESS is not set
+# CONFIG_PSTORE_LZ4_COMPRESS is not set
+CONFIG_PSTORE_CONSOLE=y
+CONFIG_PSTORE_PMSG=y
+CONFIG_PSTORE_RAM=y
 # CONFIG_SYSV_FS is not set
 # CONFIG_UFS_FS is not set
 CONFIG_NETWORK_FILESYSTEMS=y

general/overlay/etc/init.d/S29pstore

@@ -0,0 +1,21 @@
+#!/bin/sh
+# Mount the pstore filesystem so a kernel crash log that ramoops captured across
+# the reboot (a panic/oops, via kmsg_dump -- independent of the muted console)
+# is readable at /sys/fs/pstore. Without this the records are held in the
+# reserved RAM region but never exposed. Inert on a kernel built without pstore.
+# The backing RAM region is set up in the goke set_allocator (ramoops.* bootargs).
+case "$1" in
+	start)
+		if grep -q pstore /proc/filesystems; then
+			mkdir -p /sys/fs/pstore
+			mountpoint -q /sys/fs/pstore 2>/dev/null ||
+				mount -t pstore pstore /sys/fs/pstore
+		fi
+		;;
+	stop)
+		;;
+	*)
+		echo "Usage: $0 {start|stop}"
+		exit 1
+		;;
+esac

general/overlay/init

@@ -12,8 +12,12 @@ grep -q overlay /proc/filesystems || exit 1
 
 is_flash_root=true
 is_nfs_root=false
-grep -q 'root=.*nfs\|mmcblk\|ram' /proc/cmdline && is_flash_root=false
-grep -q 'root=.*nfs' /proc/cmdline && is_nfs_root=true
+# Anchor these to the root= value. A bare "ram"/"mmcblk"/"nfs" matched the whole
+# command line, so any unrelated token carrying those letters -- e.g. the
+# "ramoops" crash-log parameters -- was mistaken for a ramdisk/SD/NFS root, the
+# flash overlay was never mounted, and the camera booted read-only and unclaimed.
+grep -qE 'root=[^ ]*(nfs|mmcblk|ram)' /proc/cmdline && is_flash_root=false
+grep -qE 'root=[^ ]*nfs' /proc/cmdline && is_nfs_root=true
 
 if $is_flash_root; then
 	if grep -q ubifs /proc/cmdline; then