diff options
Diffstat (limited to 'chromium/docs/website/site/chromium-os/how-tos-and-troubleshooting/kernel-configuration/index.md')
| -rw-r--r-- | chromium/docs/website/site/chromium-os/how-tos-and-troubleshooting/kernel-configuration/index.md | 279 |
1 files changed, 0 insertions, 279 deletions
diff --git a/chromium/docs/website/site/chromium-os/how-tos-and-troubleshooting/kernel-configuration/index.md b/chromium/docs/website/site/chromium-os/how-tos-and-troubleshooting/kernel-configuration/index.md deleted file mode 100644 index 9e521dcf166..00000000000 --- a/chromium/docs/website/site/chromium-os/how-tos-and-troubleshooting/kernel-configuration/index.md +++ /dev/null @@ -1,279 +0,0 @@ ---- -breadcrumbs: -- - /chromium-os - - Chromium OS -- - /chromium-os/how-tos-and-troubleshooting - - How Tos and Troubleshooting -page_name: kernel-configuration -title: Kernel Configuration ---- - -[TOC] - -## Overview - -Kernel configuration is a little complicated in Chromium OS. There are a number -of different kernels based on architecture (x86_64, arm64) variants (generic, -rockchip) and platforms (Seaboard, Mario). We want to split the config into a -sort of hierarchy so that the common options are shared between the variants -(click to enlarge): - -[<img alt="image" -src="/chromium-os/how-tos-and-troubleshooting/kernel-configuration/kernel_config_diag.png" -height=274 -width=400>](/chromium-os/how-tos-and-troubleshooting/kernel-configuration/kernel_config_diag.png) - -Shown here are 6 flavours, three for ARM and three for Intel (it is not clear -why flavours is spelt the British way). - -## Conversions - -We need to be able to do the following: - -* create a .config file for a particular flavour - this is done simply - by concatenating the three levels for a particular flavour. For - example we create the tegra2 flavour by concatenating base.config, - armel/common.config and armel/chromeos-tegra2.flavour.config. This - .config file is suitable for configuring the kernel. -* split a .config into its constituent parts. This is a little more - complicated and has to be done for all flavours at once. Given a - .config file for each flavour we can look for items which are common - to all flavours - these can be put into the family config. We also - look for everything common within each architecture - these are put - into the architecture files like config.common.arm. The splitconfig - script does this. - -## Scripts - -Scripts to deal with the kernel configuration are in the chromeos/scripts -directory. A partial listing is shown below: - -```none -$ ls chromeos/scripts/ -kernelconfig prepareconfig -``` - -### kernelconfig - -This script deals with each separate flavour in turn, performing the selected -operations. It starts by building the config for each flavour, does the -operations, and afterwards it splits the flavour configs back into the proper -hierarchy. It supports four operations - -* oldconfig - does a 'make oldconfig' on each config -* olddefconfig - like 'oldconfig', but it accepts the default - selections automatically -* editconfig - does a 'make menuconfig' on each config -* genconfig - like oldconfig, but it leaves the generated full config - files lying around afterwards in the CONFIGS directory - -There is a bit of a problem with kernelconfig. If you want to change a kernel -option which is common to all flavours, for example, then you must change it -once for each flavour using 'kernelconfig editconfig'. At the moment this is ~10 -times! If you miss one, then the result may be no change which can be very -confusing. See below for another approach. - -### prepareconfig - -This is used to prepare the config for a particular flavour. It assembles the -default config for the flavour. This is useful when starting development on a -board and you want to build in-tree: - -```none -CHROMEOS_KERNEL_FAMILY=chromeos ./chromeos/scripts/prepareconfig chromeos-tegra2 -export ARCH=arm -export CROSS_COMPILE=armv7a-cros-linux-gnueabi- -make olddefconfig #(to pick up new options, if any) -make -... -``` - -prepareconfig requires an environment variable `CHROMEOS_KERNEL_FAMILY` to -correctly determine the split config. Above example uses `chromeos` as the -kernel family. Each supported kernel family's split config is maintained in -`chromeos/config/<family>/` directory. - -This script is used in the emerge. An example resulting string is 'Ubuntu -2.6.32-0.1-chromeos-tegra2'. - -## Using the kernelconfig script - -The kernel config is split into several config files - generic, chrome-specific, -architecture-specific and board specific. Automatic tools split and combine -these configs. - -If you want to edit the configuration for a particular board etc. then you need -to do something like: - -```none -$ cd .../src/third_party/kernel/v$VER/ -$ ./chromeos/scripts/kernelconfig editconfig -``` - -The exact value for $VER depends on your board as each one is different. You can -find that out by seeing what version by running `` `emerge-$BOARD -pv -virtual/linux-sources` ``. - -This will run 'make menuconfig' for each part of the config. - -You need to figure out which part your config options appear in, and then make -the changes when that config comes up. When it says 'press a key', you have to -press <enter>. - -## Make a change to the config - -Run editconfig to modify each config appropriately using menuconfig and then -regenerate the splitconfigs. The editconfig script will run "make menuconfig" on -each flavor config. Please make appropriate changes for each menuconfig run and -the script will generate the correct splitconfig. - -```none -cd /path/to/kernel -chromeos/scripts/kernelconfig editconfig # regenerate splitconfig -``` - -## Alternative Method to Edit Config - -This is a little faster if you know what you're doing: - -* Look for the kernel config option you want to edit. - -```none -$ grep -rs CONFIG_IO_URING chromeos/config/ -chromeos/config/manatee/base.config:# CONFIG_IO_URING is not set -chromeos/config/chromeos/base.config:# CONFIG_IO_URING is not set -``` - -* Now assuming that we are working with chromeos kernel family, edit the file - `chromeos/config/chromeos/base.config` to change the config like this: - -<pre><code> -# CONFIG_NETPOLL_TRAP is not set -<s># CONFIG_NETWORK_FILESYSTEMS is not set</s> -CONFIG_NETWORK_FILESYSTEMS=y -CONFIG_NETWORK_SECMARK=y -# CONFIG_NET_9P is not set -</code></pre> - -* Now run this to recreate all the configs based on your changes - -```none -$ chromeos/scripts/kernelconfig olddefconfig -``` - -* This will accept the default choices for any new or otherwise - unspecified options. If needed you can change them by editing the - file on your next run around this method. -* Rinse and repeat - -If you find that during that last step, your configs are disappearing, then -you've likely enabled a config without enabling all of its dependencies. You'll -need to either 1) track down those dependencies and enable them as well, or 2) -Use the editconfig method mentioned above. - -## Comparing in-tree config to split config - -This might not be useful, but: - -```none -# get full flavour config sorted, without leading # -FLAVOUR=chromeos-tegra2 cat chromeos/config/*/base.config \ - chromeos/config/*/armel/common.config \ - chromeos/config/*/armel/$FLAVOUR.flavour.config | \ - grep CONFIG_ | sed "s/.*CONFIG/CONFIG/" | sort -u >1.emerge -# purify .config in the same way -``` - -```none -make ARCH=${kernarch} savedefconfig -``` - -```none -# compare -diff 1.emerge defconfig -``` - -## Manual Building - -Here is how to build the kernel yourself manually, from within the chroot. - -Make sure you have done something like: - -```none -export B="tegra2_seaboard" -export ARCH=arm -export CROSS_COMPILE=armv7a-cros-linux-gnueabi- -# indicate that you are making kernel changes -``` - -```none -cros_workon --board=$B start sys-kernel/chromeos-kernel-$VER -``` - -The exact value for $VER depends on your board as each one is different. You can -find that out by seeing what version by running `` `emerge-$BOARD -pv -virtual/linux-sources` ``. - -As you probably know, the `cros_workon start` tells the build system to use your -local source install of the official source. Then set up the config: - -```none -# set up the .config file -CHROMEOS_KERNEL_FAMILY=<kernel-family> ./chromeos/scripts/prepareconfig chromeos-tegra2 -make olddefconfig -# edit config -make menuconfig -# (make your changes) -``` - -Now, after you make a kernel change, you can simply type `make` as normal: - -```none -# build the kernel and modules -make -# or maybe: build the uImage on an 8 core machine -make -j10 uImage -# or both! -make && make uImage -``` - -### Generate a new splitconfig after adding new Kconfig options - -Run olddefconfig to regenerate the splitconfigs. The olddefconfig script will -run "make olddefconfig" on each flavor config. - -```none -cd ~/trunk/src/third_party/kernel/v$VER -chromeos/scripts/kernelconfig olddefconfig # regenerate splitconfig -``` - -### Adding a new config - -Copy the new config to the appropriate place in the chromeos/config and then run -oldconfig - -```none -cd ~/trunk/src/third_party/kernel/v$VER -cp config.flavour.chromeos-new .config -make ARCH=${ARCH} olddefconfig -cp .config chromeos/config/<kernel-family>/<arch>/<flavour>.flavour.config -chromeos/scripts/kernelconfig olddefconfig # regenerate splitconfig -``` - -### How can I find the list of flavour configs - -```none -cd ~/trunk/src/third_party/kernel/v$VER -find chromeos/config -name \*.flavour.config -``` - -### How to regenerate and validate splitconfigs from single config - -```none -cd ~/trunk/src/third_party/kernel/v$VER -cp <single config> chromeos/config/<kernel-family>/<arch>/<flavour>.flavour.config -chromeos/scripts/kernelconfig olddefconfig -CHROMEOS_KERNEL_FAMILY=<kernel-family> chromeos/scripts/prepareconfig <flavour> -make ARCH=${ARCH} oldconfig -diff .config <single config> -```
\ No newline at end of file |