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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/tutorial/part1.md | 148 | ||||
| -rw-r--r-- | Documentation/tutorial/part2.md | 243 | ||||
| -rw-r--r-- | Documentation/tutorial/part3.md | 284 |
3 files changed, 355 insertions, 320 deletions
diff --git a/Documentation/tutorial/part1.md b/Documentation/tutorial/part1.md index 8902f6e035..cd8e79222d 100644 --- a/Documentation/tutorial/part1.md +++ b/Documentation/tutorial/part1.md @@ -2,11 +2,11 @@ Tutorial, part 1: Starting from scratch =========================================== This tutorial will guide you through the process of setting up a working -coreboot toolchain. In same cases you will find specific instructions for Debian (apt-get), -Fedora (dnf) and Arch Linux (pacman) based package management systems. Use the -instructions according to your system. +coreboot toolchain. In same cases you will find specific instructions +for Debian (apt-get), Fedora (dnf) and Arch Linux (pacman) based package +management systems. Use the instructions according to your system. -** Note: Summaries of each of the steps are at the end of the document. ** +**Note: Summaries of each of the steps are at the end of the document.** Download, configure, and build coreboot @@ -16,13 +16,15 @@ Download, configure, and build coreboot ### Step 1 - Install tools and libraries needed for coreboot Debian based distros: -`sudo apt-get install -y bison build-essential curl flex git gnat libncurses5-dev m4 zlib1g-dev` +`sudo apt-get install -y bison build-essential curl flex git gnat` +`libncurses5-dev m4 zlib1g-dev` Arch based distros: `sudo pacman -S base-devel curl git gcc-ada ncurses zlib` Redhat based distros: -`sudo dnf install git make gcc-gnat flex bison xz bzip2 gcc g++ ncurses-devel wget zlib-devel patch` +`sudo dnf install git make gcc-gnat flex bison xz bzip2 gcc g++` +`ncurses-devel wget zlib-devel patch` ### Step 2 - Download coreboot source tree @@ -36,8 +38,8 @@ cd coreboot ### Step 3 - Build the coreboot toolchain -Please note that this can take a significant amount of time. Use `CPUS=` to -specify number of `make` jobs to run in parallel. +Please note that this can take a significant amount of time. Use `CPUS=` +to specify number of `make` jobs to run in parallel. This will list toolchain options and supported architectures: @@ -53,12 +55,12 @@ make crossgcc-aarch64 CPUS=$(nproc) # build Aarch64 toolchain make crossgcc-riscv CPUS=$(nproc) # build RISC-V toolchain ``` -Note that the i386 toolchain is currently used for all x86 platforms, including -x86_64. +Note that the i386 toolchain is currently used for all x86 platforms, +including x86_64. -Also note that you can possibly use your system toolchain, but the results are -not reproducible, and may have issues, so this is not recommended. See step 5 -to use your system toolchain. +Also note that you can possibly use your system toolchain, but the +results are not reproducible, and may have issues, so this is not +recommended. See step 5 to use your system toolchain. ### Step 4 - Build the payload - coreinfo @@ -117,7 +119,8 @@ make savedefconfig cat defconfig ``` -There should only be two lines (or 3 if you're using the system toolchain): +There should only be two lines (or 3 if you're using the system +toolchain): ```Text CONFIG_PAYLOAD_ELF=y @@ -134,8 +137,8 @@ At the end of the build, you should see: `Build emulation/qemu-i440fx (QEMU x86 i440fx/piix4)`` -This means your build was successful. The output from the build is in the build -directory. build/coreboot.rom is the full rom file. +This means your build was successful. The output from the build is in +the build directory. build/coreboot.rom is the full rom file. Test the image using QEMU @@ -157,8 +160,8 @@ Start QEMU, and point it to the ROM you just built: qemu-system-x86_64 -bios build/coreboot.rom -serial stdio ``` -You should see the serial output of coreboot in the original console window, and -a new window will appear running the coreinfo payload. +You should see the serial output of coreboot in the original console +window, and a new window will appear running the coreinfo payload. Summary @@ -168,10 +171,10 @@ Summary ### Step 1 summary - Install tools and libraries needed for coreboot Depending on your distribution you have installed the minimum additional -software requirements to continue with downloading and building coreboot. -Not every distribution has the tools, that would be required, -installed by default. In the following we shortly introduce the purpose of the -installed packages: +software requirements to continue with downloading and building +coreboot. Not every distribution has the tools, that would be required, +installed by default. In the following we shortly introduce the purpose +of the installed packages: * `build-essential` or `base-devel` are the basic tools for building software. * `git` is needed to download coreboot from the coreboot git repository. @@ -180,67 +183,72 @@ installed packages: are needed to build the coreboot toolchain. `gcc` and `gnat` have to be of the same version. -If you started with a different distribution or package management system you -might need to install other packages. Most likely they are named slightly -different. If that is the case for you, we'd like to encourage you to contribute -to the project and submit a pull request with an update for this documentation -for your system. +If you started with a different distribution or package management +system you might need to install other packages. Most likely they are +named slightly different. If that is the case for you, we'd like to +encourage you to contribute to the project and submit a pull request +with an update for this documentation for your system. ### Step 2 summary - Download coreboot source tree -This will download a 'read-only' copy of the coreboot tree. This just means -that if you made changes to the coreboot tree, you couldn't immediately -contribute them back to the community. To pull a copy of coreboot that would -allow you to contribute back, you would first need to sign up for an account on -gerrit. +This will download a 'read-only' copy of the coreboot tree. This just +means that if you made changes to the coreboot tree, you couldn't +immediately contribute them back to the community. To pull a copy of +coreboot that would allow you to contribute back, you would first need +to sign up for an account on gerrit. ### Step 3 summary - Build the coreboot toolchain. -This builds one of the coreboot cross-compiler toolchains for X86 platforms. -Because of the variability of compilers and the other required tools between -the various operating systems that coreboot can be built on, coreboot supplies -and uses its own cross-compiler toolchain to build the binaries that end up as -part of the coreboot ROM. The toolchain provided by the operating system (the -'host toolchain') is used to build various tools that will run on the local -system during the build process. + +This builds one of the coreboot cross-compiler toolchains for X86 +platforms. Because of the variability of compilers and the other +required tools between the various operating systems that coreboot can +be built on, coreboot supplies and uses its own cross-compiler toolchain +to build the binaries that end up as part of the coreboot ROM. The +toolchain provided by the operating system (the 'host toolchain') is +used to build various tools that will run on the local system during the +build process. ### Step 4 summary - Build the payload -To actually do anything useful with coreboot, you need to build a payload to -include into the rom. The idea behind coreboot is that it does the minimum amount -possible before passing control of the machine to a payload. There are various -payloads such as grub or SeaBIOS that are typically used to boot the operating -system. Instead, we used coreinfo, a small demonstration payload that allows the -user to look at various things such as memory and the contents of the coreboot -file system (CBFS) - the pieces that make up the coreboot rom. +To actually do anything useful with coreboot, you need to build a +payload to include into the rom. The idea behind coreboot is that it +does the minimum amount possible before passing control of the machine +to a payload. There are various payloads such as grub or SeaBIOS that +are typically used to boot the operating system. Instead, we used +coreinfo, a small demonstration payload that allows the user to look at +various things such as memory and the contents of the coreboot file +system (CBFS) - the pieces that make up the coreboot rom. ### Step 5 summary - Configure the build -This step configures coreboot's build options using the menuconfig interface to -Kconfig. Kconfig is the same configuration program used by the linux kernel. It -allows you to enable, disable, and change various values to control the coreboot -build process, including which mainboard(motherboard) to use, which toolchain to -use, and how the runtime debug console should be presented and saved. -Anytime you change mainboards in Kconfig, you should always run `make distclean` -before running `make menuconfig`. Due to the way that Kconfig works, values will -be kept from the previous mainboard if you skip the clean step. This leads to a -hybrid configuration which may or may not work as expected. +This step configures coreboot's build options using the menuconfig +interface to Kconfig. Kconfig is the same configuration program used by +the linux kernel. It allows you to enable, disable, and change various +values to control the coreboot build process, including which +mainboard(motherboard) to use, which toolchain to use, and how the +runtime debug console should be presented and saved. Anytime you change +mainboards in Kconfig, you should always run `make distclean` before +running `make menuconfig`. Due to the way that Kconfig works, values +will be kept from the previous mainboard if you skip the clean step. +This leads to a hybrid configuration which may or may not work as +expected. ### Step 6 summary - Build coreboot -You may notice that a number of other pieces are downloaded at the beginning of -the build process. These are the git submodules used in various coreboot builds. -By default, the _blobs_ submodule is not downloaded. This git submodule may be -required for other builds for microcode or other binaries. To enable downloading -this submodule, select the option "Allow use of binary-only repository" in the -"General Setup" menu of Kconfig -This attempts to build the coreboot rom. The rom file itself ends up in the -build directory as 'coreboot.rom'. At the end of the build process, the build -displayed the contents of the rom file. +You may notice that a number of other pieces are downloaded at the +beginning of the build process. These are the git submodules used in +various coreboot builds. By default, the _blobs_ submodule is not +downloaded. This git submodule may be required for other builds for +microcode or other binaries. To enable downloading this submodule, +select the option "Allow use of binary-only repository" in the "General +Setup" menu of Kconfig This attempts to build the coreboot rom. The rom +file itself ends up in the build directory as 'coreboot.rom'. At the end +of the build process, the build displayed the contents of the rom file. ### Step 7 summary - Install QEMU @@ -253,11 +261,11 @@ process in a virtualised environment. Here's the command line instruction broken down: * `qemu-system-x86_64` -This starts the QEMU emulator with the i440FX host PCI bridge and PIIX3 PCI to -ISA bridge. +This starts the QEMU emulator with the i440FX host PCI bridge and PIIX3 +PCI to ISA bridge. * `-bios build/coreboot.rom` -Use the coreboot rom image that we just built. If this flag is left out, the -standard SeaBIOS image that comes with QEMU is used. +Use the coreboot rom image that we just built. If this flag is left out, +the standard SeaBIOS image that comes with QEMU is used. * `-serial stdio` -Send the serial output to the console. This allows you to view the coreboot -boot log. +Send the serial output to the console. This allows you to view the +coreboot boot log. diff --git a/Documentation/tutorial/part2.md b/Documentation/tutorial/part2.md index f24b0b6ec7..5917ed4d2b 100644 --- a/Documentation/tutorial/part2.md +++ b/Documentation/tutorial/part2.md @@ -4,28 +4,29 @@ If you already have an account, skip to Step 2. -Otherwise, go to <https://review.coreboot.org> in your preferred web browser. -Select **Sign in** in the upper right corner. +Otherwise, go to <https://review.coreboot.org> in your preferred web +browser. Select **Sign in** in the upper right corner. -Select the appropriate sign-in. For example, if you have a Google account, -select **Google OAuth2** (gerrit-oauth-provider plugin). **Note:** Your -username for the account will be the username of the account you used to -sign-in with. (ex. your Google username). +Select the appropriate sign-in. For example, if you have a Google +account, select **Google OAuth2** (gerrit-oauth-provider plugin). +**Note:** Your username for the account will be the username of the +account you used to sign-in with. (ex. your Google username). ## Step 2a: Set up SSH keys If you prefer to use an HTTP password instead, skip to Step 2b. -If you do not have an SSH key set up on your account already (as is the case -with a newly created account), follow the instructions below; otherwise, -doing so could overwrite an existing key. +If you do not have an SSH key set up on your account already (as is the +case with a newly created account), follow the instructions below; +otherwise, doing so could overwrite an existing key. In a terminal, run `ssh-keygen -t ed25519` and confirm the default path `.ssh/id_ed25519`. -Make a passphrase -- remember this phrase. It will be needed whenever you use -this public key. **Note:** You might want to use a short password, or -forego the password altogether as you will be using it very often. +Make a passphrase -- remember this phrase. It will be needed whenever +you use this public key. **Note:** You might want to use a short +password, or forego the password altogether as you will be using it very +often. Copy the content of `.ssh/id_ed25519.pub` (notice the ".pub" suffix as you need to send the public key) into the textbox "New SSH Key" at @@ -33,17 +34,19 @@ https://review.coreboot.org/settings/#SSHKeys and save it. ## Step 2b: Set up an HTTP Password -Alternatively, instead of using SSH keys, you can use an HTTP password. To do so, -after you select your name and click on **Settings** on the left-hand side, rather -than selecting **SSH Public Keys**, select **HTTP Password**. +Alternatively, instead of using SSH keys, you can use an HTTP password. +To do so, after you select your name and click on **Settings** on the +left-hand side, rather than selecting **SSH Public Keys**, select **HTTP +Password**. -Click **Generate Password**. This should fill the "Password" box with a password. Copy -the password, and add the following to your `$HOME/.netrc` file: +Click **Generate Password**. This should fill the "Password" box with a +password. Copy the password, and add the following to your +`$HOME/.netrc` file: machine review.coreboot.org login YourUserNameHere password YourPasswordHere -where YourUserNameHere is your username, and YourPasswordHere is the password you -just generated. +where YourUserNameHere is your username, and YourPasswordHere is the +password you just generated. If your system is behind a snooping HTTPS proxy, you might also have to make its SSL certificate known to curl, a system specific operation. @@ -55,26 +58,28 @@ certificate verification in git: The `--global` argument sets it for all git transfers of your local user, `false` means not to validate the certificate. -If that still doesn't allow you to pull or push changes to the server, the -proxy is likely tampering with the data stream, in which case there's nothing -we can do. +If that still doesn't allow you to pull or push changes to the server, +the proxy is likely tampering with the data stream, in which case +there's nothing we can do. ## Step 3: Clone coreboot and configure it for submitting patches -On Gerrit, click on the **Browse** tab in the upper left corner and select -**Repositories**. From the listing, select the "coreboot" repo. You may have -to click the next page arrow at the bottom a few times to find it. +On Gerrit, click on the **Browse** tab in the upper left corner and +select **Repositories**. From the listing, select the "coreboot" repo. +You may have to click the next page arrow at the bottom a few times to +find it. If you are using SSH keys, select **ssh** from the tabs under "Project -coreboot" and run the "clone with commit-msg hook" command that's provided. -This should prompt you for your id_rsa passphrase, if you previously set one. +coreboot" and run the "clone with commit-msg hook" command that's +provided. This should prompt you for your id_rsa passphrase, if you +previously set one. -**Note:** if the **ssh** option is not showing, check that you have a username -set. Click the profile picture at the top right and select **User Settings**, -then set your username in the **Profile** section. +**Note:** if the **ssh** option is not showing, check that you have a +username set. Click the profile picture at the top right and select +**User Settings**, then set your username in the **Profile** section. -If you are using HTTP, instead, select **http** from the tabs under "Project coreboot" -and run the command that appears. +If you are using HTTP, instead, select **http** from the tabs under +"Project coreboot" and run the command that appears. Now is a good time to configure your global git identity, if you haven't already. @@ -82,30 +87,32 @@ already. git config --global user.name "Your Name" git config --global user.email "Your Email" -Finally, enter the local git repository and set up repository specific hooks -and other configurations. +Finally, enter the local git repository and set up repository specific +hooks and other configurations. cd coreboot make gitconfig ## Step 4: Submit a commit -An easy first commit to make is fixing existing checkpatch errors and warnings -in the source files. To see errors that are already present, build the files in -the repository by running `make lint` in the coreboot directory. Alternatively, -if you want to run `make lint` on a specific directory, run: +An easy first commit to make is fixing existing checkpatch errors and +warnings in the source files. To see errors that are already present, +build the files in the repository by running `make lint` in the coreboot +directory. Alternatively, if you want to run `make lint` on a specific +directory, run: util/lint/lint-007-checkpatch <filepath> -where `filepath` is the filepath of the directory (ex. `src/cpu/amd/car`). +where `filepath` is the filepath of the directory (ex. +`src/cpu/amd/car`). Any changes made to files under the src directory are made locally, and can be submitted for review. -Once you finish making your desired changes, use the command line to stage -and submit your changes. An alternative and potentially easier way to stage -and submit commits is to use git cola, a graphical user interface for git. For -instructions on how to do so, skip to Step 4b. +Once you finish making your desired changes, use the command line to +stage and submit your changes. An alternative and potentially easier way +to stage and submit commits is to use git cola, a graphical user +interface for git. For instructions on how to do so, skip to Step 4b. ## Step 4a: Use the command line to stage and submit a commit @@ -119,20 +126,21 @@ To commit the change, run git commit -s -**Note:** The -s adds a signed-off-by line by the committer. Your commit should be -signed off with your name and email (i.e. **Your Name** **\<Your Email\>**, based on -what you set with git config earlier). +**Note:** The -s adds a signed-off-by line by the committer. Your commit +should be signed off with your name and email (i.e. **Your Name** +**\<Your Email\>**, based on what you set with git config earlier). -Running git commit first checks for any errors and warnings using lint. If -there are any, you must go back and fix them before submitting your commit. -You can do so by making the necessary changes, and then staging your commit again. +Running git commit first checks for any errors and warnings using lint. +If there are any, you must go back and fix them before submitting your +commit. You can do so by making the necessary changes, and then staging +your commit again. -When there are no errors or warnings, your default text editor will open. -This is where you will write your commit message. +When there are no errors or warnings, your default text editor will +open. This is where you will write your commit message. -The first line of your commit message is your commit summary. This is a brief -one-line description of what you changed in the files using the template -below: +The first line of your commit message is your commit summary. This is a +brief one-line description of what you changed in the files using the +template below: <filepath>: Short description @@ -143,29 +151,30 @@ For example, **Note:** It is good practice to use present tense in your descriptions and do not punctuate your summary. -Then hit Enter. The next paragraph should be a more in-depth explanation of the -changes you've made to the files. Again, it is good practice to use present -tense. Ex. +Then hit Enter. The next paragraph should be a more in-depth explanation +of the changes you've made to the files. Again, it is good practice to +use present tense. Ex. Fix space prohibited between function name and open parenthesis, - line over 80 characters, unnecessary braces for single statement blocks, - space required before open brace errors and warnings. - -When you have finished writing your commit message, save and exit the text -editor. You have finished committing your change. If, after submitting your -commit, you wish to make changes to it, running `git commit --amend` allows -you to take back your commit and amend it. - -When you are done with your commit, run `git push` to push your commit to -coreboot.org. **Note:** To submit as a private patch, use -`git push origin HEAD:refs/for/master%private`. Submitting as a private patch -means that your commit will be on review.coreboot.org, but is only visible to -yourself and those you add as reviewers. This mode isn't perfect: Somebody who -knows the commit ID can still fetch the change and everything it refers (e.g. -parent commits). - -This has been a quick primer on how to submit a change to Gerrit for review -using git. You may wish to review the [Gerrit code review workflow + line over 80 characters, unnecessary braces for single statement + blocks, space required before open brace errors and warnings. + +When you have finished writing your commit message, save and exit the +text editor. You have finished committing your change. If, after +submitting your commit, you wish to make changes to it, running `git +commit --amend` allows you to take back your commit and amend it. + +When you are done with your commit, run `git push` to push your commit +to coreboot.org. **Note:** To submit as a private patch, use `git push +origin HEAD:refs/for/master%private`. Submitting as a private patch +means that your commit will be on review.coreboot.org, but is only +visible to yourself and those you add as reviewers. This mode isn't +perfect: Somebody who knows the commit ID can still fetch the change and +everything it refers (e.g. parent commits). + +This has been a quick primer on how to submit a change to Gerrit for +review using git. You may wish to review the [Gerrit code review +workflow documentation](https://gerrit-review.googlesource.com/Documentation/intro-user.html#code-review), especially if you plan to work on multiple changes at the same time. @@ -196,14 +205,14 @@ in-depth explanation of the changes you've made to the files. Again, it is good practice to use present tense. Ex. Fix space prohibited between function name and open parenthesis, - line over 80 characters, unnecessary braces for single statement blocks, - space required before open brace errors and warnings. + line over 80 characters, unnecessary braces for single statement + blocks, space required before open brace errors and warnings. Then press Enter two times to move the cursor to below your description. To the left of the text boxes, there is an icon with an downward arrow. -Press the arrow and select "Sign Off." Make sure that you are signing off -with your name and email (i.e. **Your Name** **\<Your Email\>**, based on what -you set with git config earlier). +Press the arrow and select "Sign Off." Make sure that you are signing +off with your name and email (i.e. **Your Name** **\<Your Email\>**, +based on what you set with git config earlier). Now, review each of your changes and mark either individual changes or an entire file as Ready to Commit by marking it as 'Staged'. To do @@ -234,11 +243,11 @@ and the commit succeeds, move to the command line and run `git push`. Your commits can now be seen on review.coreboot.org if you select "Your" and click on "Changes" and can be reviewed by others. Your code will -first be reviewed by build bot (Jenkins), which will either give you a warning -or verify a successful build; if so, your commit will receive a +1. Other -users may also give your commit +1. For a commit to be merged, it needs -to receive a +2. **Note:** A +1 and a +1 does not make a +2. Only certain users -can give a +2. +first be reviewed by build bot (Jenkins), which will either give you a +warning or verify a successful build; if so, your commit will receive a ++1. Other users may also give your commit +1. For a commit to be merged, +it needs to receive a +2. **Note:** A +1 and a +1 does not make a +2. +Only certain users can give a +2. ## Step 6 (optional): bash-git-prompt @@ -255,9 +264,11 @@ as this one is specific to bash. Alternatively, follow the instructions below: Run the following two commands in the command line: - cd - git clone https://github.com/magicmonty/bash-git-prompt.git .bash-git-prompt --depth=1 - +```Bash +cd +git clone https://github.com/magicmonty/bash-git-prompt.git \ + .bash-git-prompt --depth=1 +``` **Note:** cd will change your directory to your home directory, so the git clone command will be run there. @@ -269,36 +280,38 @@ Finally, open the `~/.bashrc` file and append the following two lines: Now, whenever you are in a git repository, it will continuously display its state. -There also are additional configurations that you can change depending on your -preferences. If you wish to do so, look at the "All configs for .bashrc" section -on <https://github.com/magicmonty/bash-git-prompt>. Listed in that section are -various lines that you can copy, uncomment and add to your .bashrc file to -change the configurations. Example configurations include avoid fetching remote -status, and supporting versions of Git older than 1.7.10. +There also are additional configurations that you can change depending +on your preferences. If you wish to do so, look at the "All configs for +.bashrc" section on <https://github.com/magicmonty/bash-git-prompt>. +Listed in that section are various lines that you can copy, uncomment +and add to your .bashrc file to change the configurations. Example +configurations include avoid fetching remote status, and supporting +versions of Git older than 1.7.10. ## Appendix: Miscellaneous Advice ### Updating a commit after running git push: -Suppose you would like to update a commit that has already been pushed to the -remote repository. If the commit you wish to update is the most recent -commit you have made, after making your desired changes, stage the files -(either using git add or in git cola), and amend the commit. To do so, -if you are using the command line, run `git commit --amend`. If you are -using git cola, click on the gear icon located on the upper left side under -**Commit** and select **Amend Last Commit** in the drop down menu. Then, stage -the files you have changed, commit the changes, and run git push to push the -changes to the remote repository. Your change should be reflected in Gerrit as -a new patch set. - -If, however, the commit you wish to update is not the most recent commit you -have made, you will first need to checkout that commit. To do so, find the -URL of the commit on <https://review.coreboot.org> and go to that page; if -the commit is one that you previously pushed, it can be found by selecting -**My** and then **Changes** in the upper left corner. To checkout this commit, -in the upper right corner, click on **Download**, and copy the command listed -next to checkout by clicking **Copy to clipboard**. Then, run the copied -command in your coreboot repository. Now, the last commit should be the most -recent commit to that patch; to update it, make your desired changes, stage -the files, then amend and push the commit using the instructions in the above +Suppose you would like to update a commit that has already been pushed +to the remote repository. If the commit you wish to update is the most +recent commit you have made, after making your desired changes, stage +the files (either using git add or in git cola), and amend the commit. +To do so, if you are using the command line, run `git commit --amend`. +If you are using git cola, click on the gear icon located on the upper +left side under **Commit** and select **Amend Last Commit** in the drop +down menu. Then, stage the files you have changed, commit the changes, +and run git push to push the changes to the remote repository. Your +change should be reflected in Gerrit as a new patch set. + +If, however, the commit you wish to update is not the most recent commit +you have made, you will first need to checkout that commit. To do so, +find the URL of the commit on <https://review.coreboot.org> and go to +that page; if the commit is one that you previously pushed, it can be +found by selecting **My** and then **Changes** in the upper left corner. +To checkout this commit, in the upper right corner, click on +**Download**, and copy the command listed next to checkout by clicking +**Copy to clipboard**. Then, run the copied command in your coreboot +repository. Now, the last commit should be the most recent commit to +that patch; to update it, make your desired changes, stage the files, +then amend and push the commit using the instructions in the above paragraph. diff --git a/Documentation/tutorial/part3.md b/Documentation/tutorial/part3.md index dc487182c1..83b34088c3 100644 --- a/Documentation/tutorial/part3.md +++ b/Documentation/tutorial/part3.md @@ -1,31 +1,32 @@ # Writing unit tests for coreboot ## Introduction -General thoughts about unit testing coreboot can be found in -[Unit testing coreboot](../technotes/2020-03-unit-testing-coreboot.md). -Additionally, [code coverage](../technotes/2021-05-code-coverage.md) support -is available for unit tests. - -This document aims to guide developers through the process of adding and writing -unit tests for coreboot modules. - -As an example of unit under test, `src/device/i2c.c` (referred hereafter as UUT -"Unit Under Test") will be used. This is simple module, thus it should be easy -for the reader to focus solely on the testing logic, without the need to spend -too much time on digging deeply into the source code details and flow of -operations. That being said, a good understanding of what the unit under test is -doing is crucial for writing unit tests. +General thoughts about unit testing coreboot can be found in [Unit +testing coreboot](../technotes/2020-03-unit-testing-coreboot.md). +Additionally, [code coverage](../technotes/2021-05-code-coverage.md) +support is available for unit tests. + +This document aims to guide developers through the process of adding and +writing unit tests for coreboot modules. + +As an example of unit under test, `src/device/i2c.c` (referred hereafter +as UUT "Unit Under Test") will be used. This is simple module, thus it +should be easy for the reader to focus solely on the testing logic, +without the need to spend too much time on digging deeply into the +source code details and flow of operations. That being said, a good +understanding of what the unit under test is doing is crucial for +writing unit tests. This tutorial should also be helpful for developers who want to follow -[TDD](https://en.wikipedia.org/wiki/Test-driven_development). Even though TDD -has a different work flow of building tests first, followed by the code that -satisfies them, the process of writing tests and adding them to the tree is the -same. +[TDD](https://en.wikipedia.org/wiki/Test-driven_development). Even +though TDD has a different work flow of building tests first, followed +by the code that satisfies them, the process of writing tests and adding +them to the tree is the same. -## Analysis of unit under test -First of all, it is necessary to precisely establish what we want to test in a -particular module. Usually this will be an externally exposed API, which can be -used by other modules. +## Analysis of unit under test First of all, it is necessary to +precisely establish what we want to test in a particular module. Usually +this will be an externally exposed API, which can be used by other +modules. ```eval_rst .. admonition:: i2c-test example @@ -34,66 +35,70 @@ used by other modules. .. code-block:: c - int i2c_read_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t *data, - uint8_t mask, uint8_t shift) - int i2c_write_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t data, - uint8_t mask, uint8_t shift) + int i2c_read_field(unsigned int bus, uint8_t chip, uint8_t reg, + uint8_t *data, uint8_t mask, uint8_t shift) + int i2c_write_field(unsigned int bus, uint8_t chip, uint8_t reg, + uint8_t data, uint8_t mask, uint8_t shift) - For sake of simplicity, let's focus on `i2c_read_field` in this document. + For sake of simplicity, let's focus on `i2c_read_field` in this + document. ``` -Once the API is defined, the next question is __what__ this API is doing (or -what it will be doing in case of TDD). In other words, what outputs we are -expecting from particular functions, when providing particular input parameters. +Once the API is defined, the next question is __what__ this API is doing +(or what it will be doing in case of TDD). In other words, what outputs +we are expecting from particular functions, when providing particular +input parameters. ```eval_rst .. admonition:: i2c-test example .. code-block:: c - int i2c_read_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t *data, - uint8_t mask, uint8_t shift) + int i2c_read_field(unsigned int bus, uint8_t chip, uint8_t reg, + uint8_t *data, uint8_t mask, uint8_t shift) - This is a method which means to read content of register `reg` from i2c device - on i2c `bus` and slave address `chip`, applying bit `mask` and offset `shift` - to it. Returned data should be placed in `data`. + This is a method which means to read content of register `reg` from + i2c device on i2c `bus` and slave address `chip`, applying bit `mask` + and offset `shift` to it. Returned data should be placed in `data`. ``` -The next step is to determine all external dependencies of UUT in order to mock -them out. Usually we want to isolate the UUT as much as possible, so that the -test result depends __only__ on the behavior of UUT and not on the other -modules. While some software dependencies may be hard to be mock (for example -due to complicated dependencies) and thus should be simply linked into the test -binaries, all hardware dependencies need to be mocked out, since in the -user-space host environment, targets hardware is not available. +The next step is to determine all external dependencies of UUT in order +to mock them out. Usually we want to isolate the UUT as much as +possible, so that the test result depends __only__ on the behavior of +UUT and not on the other modules. While some software dependencies may +be hard to be mock (for example due to complicated dependencies) and +thus should be simply linked into the test binaries, all hardware +dependencies need to be mocked out, since in the user-space host +environment, targets hardware is not available. ```eval_rst .. admonition:: i2c-test example `i2c_read_field` is calling `i2c_readb`, which eventually invokes - `i2c_transfer`. This method simply calls `platform_i2c_transfer`. The last - function in the chain is a hardware-touching one, and defined separately for - different SOCs. It is responsible for issuing transactions on the i2c bus. - For the purpose of writing unit test, we should mock this function. + `i2c_transfer`. This method simply calls `platform_i2c_transfer`. The + last function in the chain is a hardware-touching one, and defined + separately for different SOCs. It is responsible for issuing + transactions on the i2c bus. For the purpose of writing unit test, + we should mock this function. ``` ## Adding new tests -In order to keep the tree clean, the `tests/` directory should mimic the `src/` -directory, so that test harness code is placed in a location corresponding to -UUT. Furthermore, the naming convention is to add the suffix `-test` to the UUT -name when creating a new test harness file. +In order to keep the tree clean, the `tests/` directory should mimic the +`src/` directory, so that test harness code is placed in a location +corresponding to UUT. Furthermore, the naming convention is to add the +suffix `-test` to the UUT name when creating a new test harness file. ```eval_rst .. admonition:: i2c-test example Considering that UUT is `src/device/i2c.c`, test file should be named - `tests/device/i2c-test.c`. When adding a new test file, it needs to be - registered with the coreboot unit testing infrastructure. + `tests/device/i2c-test.c`. When adding a new test file, it needs to + be registered with the coreboot unit testing infrastructure. ``` -Every directory under `tests/` should contain a Makefile.inc, similar to what -can be seen under the `src/`. Register a new test in Makefile.inc, by -__appending__ test name to the `tests-y` variable. +Every directory under `tests/` should contain a Makefile.inc, similar to +what can be seen under the `src/`. Register a new test in Makefile.inc, +by __appending__ test name to the `tests-y` variable. ```eval_rst .. admonition:: i2c-test example @@ -103,10 +108,11 @@ __appending__ test name to the `tests-y` variable. tests-y += i2c-test ``` -Next step is to list all source files, which should be linked together in order -to create test binary. Usually a tests requires only two files - UUT and test -harness code, but sometimes more is needed to provide the test environment. -Source files are registered in `<test_name>-srcs` variable. +Next step is to list all source files, which should be linked together +in order to create test binary. Usually a tests requires only two files +- UUT and test harness code, but sometimes more is needed to provide the +test environment. Source files are registered in `<test_name>-srcs` +variable. ```eval_rst .. admonition:: i2c-test example @@ -117,9 +123,10 @@ Source files are registered in `<test_name>-srcs` variable. i2c-test-srcs += src/device/i2c.c ``` -Above minimal configuration is a basis for further work. One can try to build -and run test binary either by invoking `make tests/<test_dir>/<test_name>` or by -running all unit tests (whole suite) for coreboot `make unit-tests`. +Above minimal configuration is a basis for further work. One can try to +build and run test binary either by invoking `make +tests/<test_dir>/<test_name>` or by running all unit tests (whole suite) +for coreboot `make unit-tests`. ```eval_rst .. admonition:: i2c-test example @@ -135,31 +142,34 @@ running all unit tests (whole suite) for coreboot `make unit-tests`. make unit-tests ``` -When trying to build test binary, one can often see linker complains about -`undefined reference` to couple of symbols. This is one of solutions to -determine all external dependencies of UUT - iteratively build test and resolve -errors one by one. At this step, developer should decide either it's better to -add an extra module to provide necessary definitions or rather mock such -dependency. Quick guide through adding mocks is provided later in this doc. +When trying to build test binary, one can often see linker complains +about `undefined reference` to couple of symbols. This is one of +solutions to determine all external dependencies of UUT - iteratively +build test and resolve errors one by one. At this step, developer should +decide either it's better to add an extra module to provide necessary +definitions or rather mock such dependency. Quick guide through adding +mocks is provided later in this doc. ## Writing new tests -In coreboot, [Cmocka](https://cmocka.org/) is used as unit test framework. The -project has exhaustive [API documentation](https://api.cmocka.org/). Let's see -how we may incorporate it when writing tests. +In coreboot, [Cmocka](https://cmocka.org/) is used as unit test +framework. The project has exhaustive [API +documentation](https://api.cmocka.org/). Let's see how we may +incorporate it when writing tests. ### Assertions -Testing the UUT consists of calling the functions in the UUT and comparing the -returned values to the expected values. Cmocka implements -[a set of assert macros](https://api.cmocka.org/group__cmocka__asserts.html) to -compare a value with an expected value. If the two values do not match, the test +Testing the UUT consists of calling the functions in the UUT and +comparing the returned values to the expected values. Cmocka implements +[a set of assert +macros](https://api.cmocka.org/group__cmocka__asserts.html) to compare a +value with an expected value. If the two values do not match, the test fails with an error message. ```eval_rst .. admonition:: i2c-test example - In our example, the simplest test is to call UUT for reading our fake devices - registers and do all calculation in the test harness itself. At the end, let's - compare integers with `assert_int_equal`. + In our example, the simplest test is to call UUT for reading our fake + devices registers and do all calculation in the test harness itself. + At the end, let's compare integers with `assert_int_equal`. .. code-block:: c @@ -191,24 +201,25 @@ fails with an error message. ### Mocks #### Overview -Many coreboot modules are low level software that touch hardware directly. -Because of this, one of the most important and challenging part of -writing tests is to design and implement mocks. A mock is a software component -which implements the API of another component so that the test can verify that -certain functions are called (or not called), verify the parameters passed to -those functions, and specify the return values from those functions. Mocks are -especially useful when the API to be implemented is one that accesses hardware -components. - -When writing a mock, the developer implements the same API as the module being -mocked. Such a mock may, for example, register a set of driver methods. Behind -this API, there is usually a simulation of real hardware. +Many coreboot modules are low level software that touch hardware +directly. Because of this, one of the most important and challenging +part of writing tests is to design and implement mocks. A mock is a +software component which implements the API of another component so that +the test can verify that certain functions are called (or not called), +verify the parameters passed to those functions, and specify the return +values from those functions. Mocks are especially useful when the API to +be implemented is one that accesses hardware components. + +When writing a mock, the developer implements the same API as the module +being mocked. Such a mock may, for example, register a set of driver +methods. Behind this API, there is usually a simulation of real +hardware. ```eval_rst .. admonition:: i2c-test example - For purpose of our i2c test, we may introduce two i2c devices with set of - registers, which simply are structs in memory. + For purpose of our i2c test, we may introduce two i2c devices with + set of registers, which simply are structs in memory. .. code-block:: c @@ -266,16 +277,17 @@ this API, there is usually a simulation of real hardware. }; ``` -Cmocka uses a feature that gcc provides for breaking dependencies at the link -time. It is possible to override implementation of some function, with the -method from test harness. This allows test harness to take control of execution -from binary (during the execution of test), and stimulate UUT as required -without changing the source code. +Cmocka uses a feature that gcc provides for breaking dependencies at the +link time. It is possible to override implementation of some function, +with the method from test harness. This allows test harness to take +control of execution from binary (during the execution of test), and +stimulate UUT as required without changing the source code. -coreboot unit test infrastructure supports overriding of functions at link time. -This is as simple as adding a `name_of_function` to be mocked into -<test_name>-mocks variable in Makefile.inc. The result is that the test's -implementation of that function is called instead of coreboot's. +coreboot unit test infrastructure supports overriding of functions at +link time. This is as simple as adding a `name_of_function` to be +mocked into <test_name>-mocks variable in Makefile.inc. The result is +that the test's implementation of that function is called instead of +coreboot's. ```eval_rst .. admonition:: i2c-test example @@ -284,44 +296,45 @@ implementation of that function is called instead of coreboot's. i2c-test-mocks += platform_i2c_transfer - Now, dev can write own implementation of `platform_i2c_transfer`. This - implementation instead of accessing real i2c bus, will write/read from - fake structs. + Now, dev can write own implementation of `platform_i2c_transfer`. + This implementation instead of accessing real i2c bus, will + write/read from fake structs. .. code-block:: c - int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments, - int count) + int platform_i2c_transfer(unsigned int bus, struct i2c_msg + *segments, int count) { } ``` #### Checking mock's arguments -A test can verify the parameters provided by the UUT to the mock function. The -developer may also verify that number of calls to mock is correct and the order -of calls to particular mocks is as expected (See -[this](https://api.cmocka.org/group__cmocka__call__order.html)). The Cmocka -macros for checking parameters are described -[here](https://api.cmocka.org/group__cmocka__param.html). In general, in mock -function, one makes a call to `check_expected(<param_name>)` and in the -corresponding test function, `expect*()` macro, with description which parameter -in which mock should have particular value, or be inside a described range. +A test can verify the parameters provided by the UUT to the mock +function. The developer may also verify that number of calls to mock is +correct and the order of calls to particular mocks is as expected (See +[this](https://api.cmocka.org/group__cmocka__call__order.html)). The +Cmocka macros for checking parameters are described +[here](https://api.cmocka.org/group__cmocka__param.html). In general, in +mock function, one makes a call to `check_expected(<param_name>)` and in +the corresponding test function, `expect*()` macro, with description +which parameter in which mock should have particular value, or be inside +a described range. ```eval_rst .. admonition:: i2c-test example - In our example, we may want to check that `platform_i2c_transfer` is fed with - number of segments bigger than 0, each segment has flags which are in - supported range and each segment has buf which is non-NULL. We are expecting - such values for _every_ call, thus the last parameter in `expect*` macros is - -1. + In our example, we may want to check that `platform_i2c_transfer` is + fed with number of segments bigger than 0, each segment has flags + which are in supported range and each segment has buf which is + non-NULL. We are expecting such values for _every_ call, thus the + last parameter in `expect*` macros is -1. .. code-block:: c static void mock_expect_params_platform_i2c_transfer(void) { - unsigned long int expected_flags[] = {0, I2C_M_RD, I2C_M_TEN, - I2C_M_RECV_LEN, I2C_M_NOSTART}; + unsigned long int expected_flags[] = {0, I2C_M_RD, + I2C_M_TEN, I2C_M_RECV_LEN, I2C_M_NOSTART}; /* Flags should always be only within supported range */ expect_in_set_count(platform_i2c_transfer, segments->flags, @@ -330,8 +343,8 @@ in which mock should have particular value, or be inside a described range. expect_not_value_count(platform_i2c_transfer, segments->buf, NULL, -1); - expect_in_range_count(platform_i2c_transfer, count, 1, INT_MAX, - -1); + expect_in_range_count(platform_i2c_transfer, count, 1, + INT_MAX, -1); } And the checks below should be added to our mock @@ -347,11 +360,11 @@ in which mock should have particular value, or be inside a described range. ``` #### Instrument mocks -It is possible for the test function to instrument what the mock will return to -the UUT. This can be done by using the `will_return*()` and `mock()` macros. -These are described in -[the Mock Object section](https://api.cmocka.org/group__cmocka__mock.html) of -the Cmocka API documentation. +It is possible for the test function to instrument what the mock will +return to the UUT. This can be done by using the `will_return*()` and +`mock()` macros. These are described in [the Mock Object +section](https://api.cmocka.org/group__cmocka__mock.html) of the Cmocka +API documentation. ```eval_rst .. admonition:: Example @@ -361,17 +374,18 @@ the Cmocka API documentation. ``` ### Test runner -Finally, the developer needs to implement the test `main()` function. All tests -should be registered there and cmocka test runner invoked. All methods for -invoking Cmocka test are described +Finally, the developer needs to implement the test `main()` function. +All tests should be registered there and cmocka test runner invoked. All +methods for invoking Cmocka test are described [here](https://api.cmocka.org/group__cmocka__exec.html). ```eval_rst .. admonition:: i2c-test example - We don't need any extra setup and teardown functions for i2c-test, so let's - simply register test for `i2c_read_field` and return from main value which is - output of Cmocka's runner (it returns number of tests that failed). + We don't need any extra setup and teardown functions for i2c-test, so + let's simply register test for `i2c_read_field` and return from main + value which is output of Cmocka's runner (it returns number of tests + that failed). .. code-block:: c |