diff options
Diffstat (limited to 'Documentation/kbuild')
| -rw-r--r-- | Documentation/kbuild/kbuild.rst | 8 | ||||
| -rw-r--r-- | Documentation/kbuild/kconfig-language.rst | 4 | ||||
| -rw-r--r-- | Documentation/kbuild/llvm.rst | 3 | ||||
| -rw-r--r-- | Documentation/kbuild/makefiles.rst | 14 | ||||
| -rw-r--r-- | Documentation/kbuild/modules.rst | 29 |
5 files changed, 54 insertions, 4 deletions
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst index 1796b3eba37b..17c9f920f03d 100644 --- a/Documentation/kbuild/kbuild.rst +++ b/Documentation/kbuild/kbuild.rst @@ -137,12 +137,18 @@ Specify the output directory when building the kernel. This variable can also be used to point to the kernel output directory when building external modules against a pre-built kernel in a separate build directory. Please note that this does NOT specify the output directory for the -external modules themselves. +external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.) The output directory can also be specified using "O=...". Setting "O=..." takes precedence over KBUILD_OUTPUT. +KBUILD_EXTMOD_OUTPUT +-------------------- +Specify the output directory for external modules. + +Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT. + KBUILD_EXTRA_WARN ----------------- Specify the extra build checks. The same value can be assigned by passing diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index 43037be96a16..2619fdf56e68 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -412,8 +412,8 @@ choices:: <choice block> "endchoice" -This defines a choice group and accepts any of the above attributes as -options. +This defines a choice group and accepts "prompt", "default", "depends on", and +"help" attributes as options. A choice only allows a single config entry to be selected. diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst index 6dc66b4f31a7..bc8a283bc44b 100644 --- a/Documentation/kbuild/llvm.rst +++ b/Documentation/kbuild/llvm.rst @@ -179,6 +179,9 @@ yet. Bug reports are always welcome at the issue tracker below! * - s390 - Maintained - ``LLVM=1`` (LLVM >= 18.1.0), ``CC=clang`` (LLVM < 18.1.0) + * - sparc (sparc64 only) + - Maintained + - ``CC=clang LLVM_IAS=0`` (LLVM >= 20) * - um (User Mode) - Maintained - ``LLVM=1`` diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst index 7964e0c245ae..d36519f194dc 100644 --- a/Documentation/kbuild/makefiles.rst +++ b/Documentation/kbuild/makefiles.rst @@ -449,6 +449,20 @@ $(obj) to prerequisites are referenced with $(src) (because they are not generated files). +$(srcroot) + $(srcroot) refers to the root of the source you are building, which can be + either the kernel source or the external modules source, depending on whether + KBUILD_EXTMOD is set. This can be either a relative or an absolute path, but + if KBUILD_ABS_SRCTREE=1 is set, it is always an absolute path. + +$(srctree) + $(srctree) refers to the root of the kernel source tree. When building the + kernel, this is the same as $(srcroot). + +$(objtree) + $(objtree) refers to the root of the kernel object tree. It is ``.`` when + building the kernel, but it is different when building external modules. + $(kecho) echoing information to user in a rule is often a good practice but when execution ``make -s`` one does not expect to see any output diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index cd5a54d91e6d..101de236cd0c 100644 --- a/Documentation/kbuild/modules.rst +++ b/Documentation/kbuild/modules.rst @@ -59,6 +59,12 @@ Command Syntax $ make -C /lib/modules/`uname -r`/build M=$PWD modules_install + Starting from Linux 6.13, you can use the -f option instead of -C. This + will avoid unnecessary change of the working directory. The external + module will be output to the directory where you invoke make. + + $ make -f /lib/modules/`uname -r`/build/Makefile M=$PWD + Options ------- @@ -66,7 +72,10 @@ Options of the kernel output directory if the kernel was built in a separate build directory.) - make -C $KDIR M=$PWD + You can optionally pass MO= option if you want to build the modules in + a separate directory. + + make -C $KDIR M=$PWD [MO=$BUILD_DIR] -C $KDIR The directory that contains the kernel and relevant build @@ -80,6 +89,9 @@ Options directory where the external module (kbuild file) is located. + MO=$BUILD_DIR + Specifies a separate output directory for the external module. + Targets ------- @@ -215,6 +227,21 @@ Separate Kbuild File and Makefile consisting of several hundred lines, and here it really pays off to separate the kbuild part from the rest. + Linux 6.13 and later support another way. The external module Makefile + can include the kernel Makefile directly, rather than invoking sub Make. + + Example 3:: + + --> filename: Kbuild + obj-m := 8123.o + 8123-y := 8123_if.o 8123_pci.o + + --> filename: Makefile + KDIR ?= /lib/modules/$(shell uname -r)/build + export KBUILD_EXTMOD := $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) + include $(KDIR)/Makefile + + Building Multiple Modules ------------------------- |