linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / Documentation / kbuild / modules.txt

diff --git a/Documentation/kbuild/modules.txt b/Documentation/kbuild/modules.txt
index 61fc079..7e77f93 100644 (file)
--- a/Documentation/kbuild/modules.txt
+++ b/Documentation/kbuild/modules.txt
@@ -13,7 +13,6 @@ In this document you will find information about:
           --- 2.2 Available targets
           --- 2.3 Available options
           --- 2.4 Preparing the kernel tree for module build
           --- 2.2 Available targets
           --- 2.3 Available options
           --- 2.4 Preparing the kernel tree for module build

-          --- 2.5 Building separate files for a module

        === 3. Example commands
        === 4. Creating a kbuild file for an external module
        === 5. Include files
        === 3. Example commands
        === 4. Creating a kbuild file for an external module
        === 5. Include files


@@ -23,10 +22,7 @@ In this document you will find information about:
        === 6. Module installation
           --- 6.1 INSTALL_MOD_PATH
           --- 6.2 INSTALL_MOD_DIR
        === 6. Module installation
           --- 6.1 INSTALL_MOD_PATH
           --- 6.2 INSTALL_MOD_DIR

-       === 7. Module versioning & Module.symvers
-          --- 7.1 Symbols fron the kernel (vmlinux + modules)
-          --- 7.2 Symbols and external modules
-          --- 7.3 Symbols from another external module
+       === 7. Module versioning

        === 8. Tips & Tricks
           --- 8.1 Testing for CONFIG_FOO_BAR
 
        === 8. Tips & Tricks
           --- 8.1 Testing for CONFIG_FOO_BAR
 


@@ -44,7 +40,7 @@ What is covered within this file is mainly information to authors
 of modules. The author of an external modules should supply
 a makefile that hides most of the complexity so one only has to type
 'make' to build the module. A complete example will be present in
 of modules. The author of an external modules should supply
 a makefile that hides most of the complexity so one only has to type
 'make' to build the module. A complete example will be present in

-chapter 4, "Creating a kbuild file for an external module".
+chapter ¤. Creating a kbuild file for an external module".

 
 
 === 2. How to build external modules
 
 
 === 2. How to build external modules


@@ -92,8 +88,7 @@ when building an external module.
        make -C $KDIR M=$PWD modules_install
                Install the external module(s).
                Installation default is in /lib/modules/<kernel-version>/extra,
        make -C $KDIR M=$PWD modules_install
                Install the external module(s).
                Installation default is in /lib/modules/<kernel-version>/extra,

-               but may be prefixed with INSTALL_MOD_PATH - see separate
-               chapter.
+               but may be prefixed with INSTALL_MOD_PATH - see separate chapter.

 
        make -C $KDIR M=$PWD clean
                Remove all generated files for the module - the kernel
 
        make -C $KDIR M=$PWD clean
                Remove all generated files for the module - the kernel


@@ -136,16 +131,6 @@ when building an external module.
              Therefore a full kernel build needs to be executed to make
              module versioning work.
 
              Therefore a full kernel build needs to be executed to make
              module versioning work.
 

---- 2.5 Building separate files for a module
-       It is possible to build single files which is part of a module.
-       This works equal for the kernel, a module and even for external
-       modules.
-       Examples (module foo.ko, consist of bar.o, baz.o):
-               make -C $KDIR M=`pwd` bar.lst
-               make -C $KDIR M=`pwd` bar.o
-               make -C $KDIR M=`pwd` foo.ko
-               make -C $KDIR M=`pwd` /
-       

 
 === 3. Example commands
 
 
 === 3. Example commands
 


@@ -437,7 +422,7 @@ External modules are installed in the directory:
                => Install dir: /lib/modules/$(KERNELRELEASE)/gandalf
 
 
                => Install dir: /lib/modules/$(KERNELRELEASE)/gandalf
 
 

-=== 7. Module versioning & Module.symvers
+=== 7. Module versioning

 
 Module versioning is enabled by the CONFIG_MODVERSIONS tag.
 
 
 Module versioning is enabled by the CONFIG_MODVERSIONS tag.
 


@@ -447,80 +432,11 @@ when a module is loaded/used then the CRC values contained in the kernel are
 compared with similar values in the module. If they are not equal then the
 kernel refuses to load the module.
 
 compared with similar values in the module. If they are not equal then the
 kernel refuses to load the module.
 

-Module.symvers contains a list of all exported symbols from a kernel build.
-
---- 7.1 Symbols fron the kernel (vmlinux + modules)
-
-       During a kernel build a file named Module.symvers will be generated.
-       Module.symvers contains all exported symbols from the kernel and
-       compiled modules. For each symbols the corresponding CRC value
-       is stored too.
-
-       The syntax of the Module.symvers file is:
-               <CRC>       <Symbol>           <module>
-       Sample:
-               0x2d036834  scsi_remove_host   drivers/scsi/scsi_mod
+During a kernel build a file named Module.symvers will be generated. This
+file includes the symbol version of all symbols within the kernel. If the 
+Module.symvers file is saved from the last full kernel compile one does not
+have to do a full kernel compile to build a module version's compatible module.

 
 

-       For a kernel build without CONFIG_MODVERSIONING enabled the crc
-       would read: 0x00000000
-
-       Module.symvers serve two purposes.
-       1) It list all exported symbols both from vmlinux and all modules
-       2) It list CRC if CONFIG_MODVERSION is enabled
-
---- 7.2 Symbols and external modules
-
-       When building an external module the build system needs access to
-       the symbols from the kernel to check if all external symbols are
-       defined. This is done in the MODPOST step and to obtain all
-       symbols modpost reads Module.symvers from the kernel.
-       If a Module.symvers file is present in the directory where
-       the external module is being build this file will be read too.
-       During the MODPOST step a new Module.symvers file will be written
-       containing all exported symbols that was not defined in the kernel.
-       
---- 7.3 Symbols from another external module
-
-       Sometimes one external module uses exported symbols from another
-       external module. Kbuild needs to have full knowledge on all symbols
-       to avoid spitting out warnings about undefined symbols.
-       Two solutions exist to let kbuild know all symbols of more than
-       one external module.
-       The method with a top-level kbuild file is recommended but may be
-       impractical in certain situations.
-
-       Use a top-level Kbuild file
-               If you have two modules: 'foo', 'bar' and 'foo' needs symbols
-               from 'bar' then one can use a common top-level kbuild file so
-               both modules are compiled in same build.
-
-               Consider following directory layout:
-               ./foo/ <= contains the foo module
-               ./bar/ <= contains the bar module
-               The top-level Kbuild file would then look like:
-               
-               #./Kbuild: (this file may also be named Makefile)
-                       obj-y := foo/ bar/
-
-               Executing:
-                       make -C $KDIR M=`pwd`
-
-               will then do the expected and compile both modules with full
-               knowledge on symbols from both modules.
-
-       Use an extra Module.symvers file
-               When an external module is build a Module.symvers file is
-               generated containing all exported symbols which are not
-               defined in the kernel.
-               To get access to symbols from module 'bar' one can copy the
-               Module.symvers file from the compilation of the 'bar' module
-               to the directory where the 'foo' module is build.
-               During the module build kbuild will read the Module.symvers
-               file in the directory of the external module and when the
-               build is finished a new Module.symvers file is created
-               containing the sum of all symbols defined and not part of the
-               kernel.
-               

 === 8. Tips & Tricks
 
 --- 8.1 Testing for CONFIG_FOO_BAR
 === 8. Tips & Tricks
 
 --- 8.1 Testing for CONFIG_FOO_BAR