Plasma/Mobile/Porting: Difference between revisions

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= Current Architecture of Plasma Mobile =
{{Note|This page is now on [[https://docs.plasma-mobile.org/Porting.html https://docs.plasma-mobile.org/]]}}
 
== For ARM devices which requires Android binary blobs ==
 
* Kernel, either provided by vendor or thirdparty with config options enabled to support LXC containers
* AOSP/LineageOS base, built with core_tiny target, just base items
* LXC container with Neon/Ubuntu rootfs containing KWin/Wayland and Plasma Mobile
 
=== Kernel ===
 
Kernel needs to support the various config options, you can use lxc-checkconfig script provided by lxc userspace tools to check if all required features are enabled, for example:
 
<pre>% CONFIG=arch/arm64/configs/bullhead_defconfig lxc-checkconfig
--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
User namespace: enabled
Network namespace: missing
Multiple /dev/pts instances: enabled
 
--- Control groups ---
Cgroup: enabled
Cgroup clone_children flag: enabled
Cgroup device: enabled
Cgroup sched: enabled
Cgroup cpu account: enabled
Cgroup memory controller: enabled
Cgroup cpuset: enabled
 
[..]</pre>
Below is the list of the config options,
 
<pre>CONFIG_CGROUP_DEVICE=y
CONFIG_CPUSETS=y
CONFIG_CGROUP_MEM_RES_CTLR=y
CONFIG_CGROUP_PERF=y
CONFIG_UTS_NS=y
CONFIG_IPC_NS=y
CONFIG_USER_NS=y
CONFIG_PID_NS=y
CONFIG_DEVPTS_MULTIPLE_INSTANCES=y</pre>
=== AOSP/LineageOS base ===
 
AOSP/LineageOS base should have all non-required things removed and some changes in base to accomodate needs of libhybris and container containing Linux system. Below is list of various changes,
 
==== Export PATH and LD_LIBRARY_PATH to point to lxc userspace tools ====
 
We use prebuilt lxc userspace tools from [https://jenkins.linuxcontainers.org/ linux containers CI]. Those are installed in /data partition which by default is not in the PATH android shell looks binaries into. Modify the system/core/rootdir/init.environ.rc file to include the path of LXC userspace tools in $PATH and export LD_LIBRARY_PATH.
 
<pre class="patch">project system/core/
diff --git a/rootdir/init.environ.rc.in b/rootdir/init.environ.rc.in
index c32337a..9d91d60 100644
--- a/rootdir/init.environ.rc.in
+++ b/rootdir/init.environ.rc.in
@@ -1,6 +1,6 @@
# set up the global environment
on init
-    export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
+    export PATH /data/lxc/lxc/bin:/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
    export ANDROID_BOOTLOGO 1
    export ANDROID_ROOT /system
    export ANDROID_ASSETS /system/app
@@ -8,6 +8,7 @@ on init
    export ANDROID_STORAGE /storage
    export ASEC_MOUNTPOINT /mnt/asec
    export LOOP_MOUNTPOINT /mnt/obb
+    export LD_LIBRARY_PATH /data/lxc/lxc/lib
    export BOOTCLASSPATH %BOOTCLASSPATH%
    export SYSTEMSERVERCLASSPATH %SYSTEMSERVERCLASSPATH%
    export LD_PRELOAD libsigchain.so%TARGET_LDPRELOAD%</pre>
However, LD_LIBRARY_PATH doesn't work for AOSP based android image and needs investigation. See [https://phabricator.kde.org/T4941 phabricator task] for more details.
 
==== Disable enforced PIE executables in bionic ====
 
==== Disable SELinux ====
 
==== Remove the nosuid,nodev option from the data partition ====
 
==== Apply bionic patch to shift TLS slots ====
 
==== Fix Permission for backlight brightness file ====
 
== For devices which don't require Android binary blobs ==
 
* Normal Linux system with kernel and drivers supporting Wayland
* KWin/Wayland and Plasma Mobile packages

Latest revision as of 22:57, 5 February 2019

Note

This page is now on [https://docs.plasma-mobile.org/]