diff options
Diffstat (limited to 'Documentation/kbuild')
| -rw-r--r-- | Documentation/kbuild/bash-completion.rst | 65 | ||||
| -rw-r--r-- | Documentation/kbuild/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/kbuild/kconfig-language.rst | 29 | ||||
| -rw-r--r-- | Documentation/kbuild/makefiles.rst | 17 | ||||
| -rw-r--r-- | Documentation/kbuild/modules.rst | 2 | ||||
| -rw-r--r-- | Documentation/kbuild/reproducible-builds.rst | 17 |
6 files changed, 100 insertions, 32 deletions
diff --git a/Documentation/kbuild/bash-completion.rst b/Documentation/kbuild/bash-completion.rst new file mode 100644 index 000000000000..2b52dbcd0933 --- /dev/null +++ b/Documentation/kbuild/bash-completion.rst @@ -0,0 +1,65 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +========================== +Bash completion for Kbuild +========================== + +The kernel build system is written using Makefiles, and Bash completion +for the `make` command is available through the `bash-completion`_ project. + +However, the Makefiles for the kernel build are complex. The generic completion +rules for the `make` command do not provide meaningful suggestions for the +kernel build system, except for the options of the `make` command itself. + +To enhance completion for various variables and targets, the kernel source +includes its own completion script at `scripts/bash-completion/make`. + +This script provides additional completions when working within the kernel tree. +Outside the kernel tree, it defaults to the generic completion rules for the +`make` command. + +Prerequisites +============= + +The script relies on helper functions provided by `bash-completion`_ project. +Please ensure it is installed on your system. On most distributions, you can +install the `bash-completion` package through the standard package manager. + +How to use +========== + +You can source the script directly:: + + $ source scripts/bash-completion/make + +Or, you can copy it into the search path for Bash completion scripts. +For example:: + + $ mkdir -p ~/.local/share/bash-completion/completions + $ cp scripts/bash-completion/make ~/.local/share/bash-completion/completions/ + +Details +======= + +The additional completion for Kbuild is enabled in the following cases: + + - You are in the root directory of the kernel source. + - You are in the top-level build directory created by the O= option + (checked via the `source` symlink pointing to the kernel source). + - The -C make option specifies the kernel source or build directory. + - The -f make option specifies a file in the kernel source or build directory. + +If none of the above are met, it falls back to the generic completion rules. + +The completion supports: + + - Commonly used targets, such as `all`, `menuconfig`, `dtbs`, etc. + - Make (or environment) variables, such as `ARCH`, `LLVM`, etc. + - Single-target builds (`foo/bar/baz.o`) + - Configuration files (`*_defconfig` and `*.config`) + +Some variables offer intelligent behavior. For instance, `CROSS_COMPILE=` +followed by a TAB displays installed toolchains. The list of defconfig files +shown depends on the value of the `ARCH=` variable. + +.. _bash-completion: https://github.com/scop/bash-completion/ diff --git a/Documentation/kbuild/index.rst b/Documentation/kbuild/index.rst index e82af05cd652..3731ab22bfe7 100644 --- a/Documentation/kbuild/index.rst +++ b/Documentation/kbuild/index.rst @@ -23,6 +23,8 @@ Kernel Build System llvm gendwarfksyms + bash-completion + .. only:: subproject and html Indices diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index 2619fdf56e68..a91abb8f6840 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -194,16 +194,6 @@ applicable everywhere (see syntax). ability to hook into a secondary subsystem while allowing the user to configure that subsystem out without also having to unset these drivers. - Note: If the combination of FOO=y and BAZ=m causes a link error, - you can guard the function call with IS_REACHABLE():: - - foo_init() - { - if (IS_REACHABLE(CONFIG_BAZ)) - baz_register(&foo); - ... - } - Note: If the feature provided by BAZ is highly desirable for FOO, FOO should imply not only BAZ, but also its dependency BAR:: @@ -588,7 +578,9 @@ uses the slightly counterintuitive:: depends on BAR || !BAR This means that there is either a dependency on BAR that disallows -the combination of FOO=y with BAR=m, or BAR is completely disabled. +the combination of FOO=y with BAR=m, or BAR is completely disabled. The BAR +module must provide all the stubs for !BAR case. + For a more formalized approach if there are multiple drivers that have the same dependency, a helper symbol can be used, like:: @@ -599,6 +591,21 @@ the same dependency, a helper symbol can be used, like:: config BAR_OPTIONAL def_tristate BAR || !BAR +Much less favorable way to express optional dependency is IS_REACHABLE() within +the module code, useful for example when the module BAR does not provide +!BAR stubs:: + + foo_init() + { + if (IS_REACHABLE(CONFIG_BAR)) + bar_register(&foo); + ... + } + +IS_REACHABLE() is generally discouraged, because the code will be silently +discarded, when CONFIG_BAR=m and this code is built-in. This is not what users +usually expect when enabling BAR as module. + Kconfig recursive dependency limitations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst index d36519f194dc..3b9a8bc671e2 100644 --- a/Documentation/kbuild/makefiles.rst +++ b/Documentation/kbuild/makefiles.rst @@ -318,9 +318,6 @@ ccflags-y, asflags-y and ldflags-y These three flags apply only to the kbuild makefile in which they are assigned. They are used for all the normal cc, as and ld invocations happening during a recursive build. - Note: Flags with the same behaviour were previously named: - EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS. - They are still supported but their usage is deprecated. ccflags-y specifies options for compiling with $(CC). @@ -670,6 +667,20 @@ cc-cross-prefix endif endif +$(RUSTC) support functions +-------------------------- + +rustc-min-version + rustc-min-version tests if the value of $(CONFIG_RUSTC_VERSION) is greater + than or equal to the provided value and evaluates to y if so. + + Example:: + + rustflags-$(call rustc-min-version, 108500) := -Cfoo + + In this example, rustflags-y will be assigned the value -Cfoo if + $(CONFIG_RUSTC_VERSION) is >= 1.85.0. + $(LD) support functions ----------------------- diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index a42f00d8cb90..d0703605bfa4 100644 --- a/Documentation/kbuild/modules.rst +++ b/Documentation/kbuild/modules.rst @@ -318,7 +318,7 @@ Several Subdirectories | |__ include | |__ hardwareif.h |__ include - |__ complex.h + |__ complex.h To build the module complex.ko, we then need the following kbuild file:: diff --git a/Documentation/kbuild/reproducible-builds.rst b/Documentation/kbuild/reproducible-builds.rst index f2dcc39044e6..a7762486c93f 100644 --- a/Documentation/kbuild/reproducible-builds.rst +++ b/Documentation/kbuild/reproducible-builds.rst @@ -46,21 +46,6 @@ The kernel embeds the building user and host names in `KBUILD_BUILD_USER and KBUILD_BUILD_HOST`_ variables. If you are building from a git commit, you could use its committer address. -Absolute filenames ------------------- - -When the kernel is built out-of-tree, debug information may include -absolute filenames for the source files. This must be overridden by -including the ``-fdebug-prefix-map`` option in the `KCFLAGS`_ variable. - -Depending on the compiler used, the ``__FILE__`` macro may also expand -to an absolute filename in an out-of-tree build. Kbuild automatically -uses the ``-fmacro-prefix-map`` option to prevent this, if it is -supported. - -The Reproducible Builds web site has more information about these -`prefix-map options`_. - Generated files in source packages ---------------------------------- @@ -131,7 +116,5 @@ See ``scripts/setlocalversion`` for details. .. _KBUILD_BUILD_TIMESTAMP: kbuild.html#kbuild-build-timestamp .. _KBUILD_BUILD_USER and KBUILD_BUILD_HOST: kbuild.html#kbuild-build-user-kbuild-build-host -.. _KCFLAGS: kbuild.html#kcflags -.. _prefix-map options: https://reproducible-builds.org/docs/build-path/ .. _Reproducible Builds project: https://reproducible-builds.org/ .. _SOURCE_DATE_EPOCH: https://reproducible-builds.org/docs/source-date-epoch/ |