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Diffstat (limited to 'Documentation/kbuild/modules.rst')
| -rw-r--r-- | Documentation/kbuild/modules.rst | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index cd5a54d91e6d..d0703605bfa4 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 ------------------------- @@ -291,7 +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:: @@ -396,6 +423,26 @@ Symbols From the Kernel (vmlinux + modules) 1) It lists all exported symbols from vmlinux and all modules. 2) It lists the CRC if CONFIG_MODVERSIONS is enabled. +Version Information Formats +--------------------------- + + Exported symbols have information stored in __ksymtab or __ksymtab_gpl + sections. Symbol names and namespaces are stored in __ksymtab_strings, + using a format similar to the string table used for ELF. If + CONFIG_MODVERSIONS is enabled, the CRCs corresponding to exported + symbols will be added to the __kcrctab or __kcrctab_gpl. + + If CONFIG_BASIC_MODVERSIONS is enabled (default with + CONFIG_MODVERSIONS), imported symbols will have their symbol name and + CRC stored in the __versions section of the importing module. This + mode only supports symbols of length up to 64 bytes. + + If CONFIG_EXTENDED_MODVERSIONS is enabled (required to enable both + CONFIG_MODVERSIONS and CONFIG_RUST at the same time), imported symbols + will have their symbol name recorded in the __version_ext_names + section as a series of concatenated, null-terminated strings. CRCs for + these symbols will be recorded in the __version_ext_crcs section. + Symbols and External Modules ---------------------------- |