diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index eda00a1073a7..a311db829e9b 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -174,7 +174,7 @@ more details, with real examples. --- 3.3 Loadable module goals - obj-m - $(obj-m) specify object files which are built as loadable + $(obj-m) specifies object files which are built as loadable kernel modules. A module may be built from one source file or several source @@ -277,7 +277,7 @@ more details, with real examples. down in the ext2 directory. Kbuild only uses this information to decide that it needs to visit the directory, it is the Makefile in the subdirectory that - specifies what is modules and what is built-in. + specifies what is modular and what is built-in. It is good practice to use a CONFIG_ variable when assigning directory names. This allows kbuild to totally skip the directory if the @@ -403,7 +403,7 @@ more details, with real examples. 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 except for warnings/errors. - To support this kbuild define $(kecho) which will echo out the + To support this kbuild defines $(kecho) which will echo out the text following $(kecho) to stdout except if "make -s" is used. Example: @@ -417,7 +417,7 @@ more details, with real examples. The kernel may be built with several different versions of $(CC), each supporting a unique set of features and options. - kbuild provide basic support to check for valid options for $(CC). + kbuild provides basic support to check for valid options for $(CC). $(CC) is usually the gcc compiler, but other alternatives are available. @@ -456,8 +456,8 @@ more details, with real examples. Note: as-instr-option uses KBUILD_AFLAGS for $(AS) options cc-option - cc-option is used to check if $(CC) supports a given option, and not - supported to use an optional second option. + cc-option is used to check if $(CC) supports a given option, and if + not supported to use an optional second option. Example: #arch/x86/Makefile @@ -557,8 +557,8 @@ more details, with real examples. false ; \ fi - In this example for a specific GCC version the build will error out explaining - to the user why it stops. + In this example for a specific GCC version the build will error out + explaining to the user why it stops. cc-cross-prefix cc-cross-prefix is used to check if there exists a $(CC) in path with @@ -656,7 +656,7 @@ Both possibilities are described in the following. In the example above the executable is composed of the C++ file qconf.cc - identified by $(qconf-cxxobjs). - If qconf is composed by a mixture of .c and .cc files, then an + If qconf is composed of a mixture of .c and .cc files, then an additional line can be used to identify this. Example: @@ -733,7 +733,7 @@ Both possibilities are described in the following. hostprogs-$(CONFIG_KALLSYMS) += kallsyms Kbuild knows about both 'y' for built-in and 'm' for module. - So if a config symbol evaluate to 'm', kbuild will still build + So if a config symbol evaluates to 'm', kbuild will still build the binary. In other words, Kbuild handles hostprogs-m exactly like hostprogs-y. But only hostprogs-y is recommended to be used when no CONFIG symbols are involved. @@ -754,8 +754,8 @@ Additional files can be specified in kbuild makefiles by use of $(clean-files). #drivers/pci/Makefile clean-files := devlist.h classlist.h -When executing "make clean", the two files "devlist.h classlist.h" will -be deleted. Kbuild will assume files to be in same relative directory as the +When executing "make clean", the two files "devlist.h classlist.h" will be +deleted. Kbuild will assume files to be in the same relative directory as the Makefile except if an absolute path is specified (path starting with '/'). To delete a directory hierarchy use: @@ -786,7 +786,7 @@ is not sufficient this sometimes needs to be explicit. The above assignment instructs kbuild to descend down in the directory compressed/ when "make clean" is executed. -To support the clean infrastructure in the Makefiles that builds the +To support the clean infrastructure in the Makefiles that build the final bootimage there is an optional target named archclean: Example: @@ -926,7 +926,7 @@ When kbuild executes, the following steps are followed (roughly): KBUILD_AFLAGS_MODULE Options for $(AS) when building modules - $(KBUILD_AFLAGS_MODULE) is used to add arch specific options that + $(KBUILD_AFLAGS_MODULE) is used to add arch-specific options that are used for $(AS). From commandline AFLAGS_MODULE shall be used (see kbuild.txt). @@ -937,13 +937,13 @@ When kbuild executes, the following steps are followed (roughly): KBUILD_CFLAGS_MODULE Options for $(CC) when building modules - $(KBUILD_CFLAGS_MODULE) is used to add arch specific options that + $(KBUILD_CFLAGS_MODULE) is used to add arch-specific options that are used for $(CC). From commandline CFLAGS_MODULE shall be used (see kbuild.txt). KBUILD_LDFLAGS_MODULE Options for $(LD) when linking modules - $(KBUILD_LDFLAGS_MODULE) is used to add arch specific options + $(KBUILD_LDFLAGS_MODULE) is used to add arch-specific options used when linking modules. This is often a linker script. From commandline LDFLAGS_MODULE shall be used (see kbuild.txt). @@ -1065,7 +1065,7 @@ When kbuild executes, the following steps are followed (roughly): extra-y - extra-y specify additional targets created in the current + extra-y specifies additional targets created in the current directory, in addition to any targets specified by obj-*. Listing all targets in extra-y is required for two purposes: @@ -1141,7 +1141,7 @@ When kbuild executes, the following steps are followed (roughly): 2) delete target during make clean The ": %: %.o" part of the prerequisite is a shorthand that - free us from listing the setup.o and bootsect.o files. + frees us from listing the setup.o and bootsect.o files. Note: It is a common mistake to forget the "targets :=" assignment, resulting in the target file being recompiled for no obvious reason. @@ -1213,11 +1213,11 @@ When kbuild executes, the following steps are followed (roughly): When building the *.lds target, kbuild uses the variables: KBUILD_CPPFLAGS : Set in top-level Makefile cppflags-y : May be set in the kbuild makefile - CPPFLAGS_$(@F) : Target specific flags. + CPPFLAGS_$(@F) : Target-specific flags. Note that the full filename is used in this assignment. - The kbuild infrastructure for *lds file are used in several + The kbuild infrastructure for *lds files is used in several architecture-specific files. --- 6.10 Generic header files @@ -1230,11 +1230,11 @@ When kbuild executes, the following steps are followed (roughly): === 7 Kbuild syntax for exported headers -The kernel include a set of headers that is exported to userspace. +The kernel includes a set of headers that is exported to userspace. Many headers can be exported as-is but other headers require a minimal pre-processing before they are ready for user-space. The pre-processing does: -- drop kernel specific annotations +- drop kernel-specific annotations - drop include of compiler.h - drop all sections that are kernel internal (guarded by ifdef __KERNEL__) @@ -1244,7 +1244,7 @@ See subsequent chapter for the syntax of the Kbuild file. --- 7.1 header-y - header-y specify header files to be exported. + header-y specifies header files to be exported. Example: #include/linux/Kbuild @@ -1254,7 +1254,7 @@ See subsequent chapter for the syntax of the Kbuild file. The convention is to list one file per line and preferably in alphabetic order. - header-y also specify which subdirectories to visit. + header-y also specifies which subdirectories to visit. A subdirectory is identified by a trailing '/' which can be seen in the example above for the usb subdirectory. @@ -1272,9 +1272,9 @@ See subsequent chapter for the syntax of the Kbuild file. --- 7.3 destination-y - When an architecture have a set of exported headers that needs to be + When an architecture has a set of exported headers that needs to be exported to a different directory destination-y is used. - destination-y specify the destination directory for all exported + destination-y specifies the destination directory for all exported headers in the file where it is present. Example: @@ -1367,9 +1367,9 @@ The top Makefile exports the following variables: INSTALL_MOD_STRIP - If this variable is specified, will cause modules to be stripped + If this variable is specified, it will cause modules to be stripped after they are installed. If INSTALL_MOD_STRIP is '1', then the - default option --strip-debug will be used. Otherwise, + default option --strip-debug will be used. Otherwise, the INSTALL_MOD_STRIP value will be used as the option(s) to the strip command.