From 052ad274964e613a12bf8ce7c5631f70d0bc82cc Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 17 Nov 2011 13:17:35 -0800 Subject: kbuild: Add support for an "archheaders" target Add support for an "archheaders" target. This target can generate files that need to be installed for user space by "make headers_install" or "make headers_install_all". In order to support "make headers_install_all", it must be able to run without the tree having to be configured first. Cc: David Woodhouse Cc: Sam Ravnborg Cc: Michal Marek Signed-off-by: H. Peter Anvin --- Documentation/kbuild/makefiles.txt | 50 ++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 18 deletions(-) (limited to 'Documentation/kbuild') diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index f47cdefb4d1e..ab0a984530d8 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -33,14 +33,15 @@ This document describes the Linux kernel Makefiles. === 6 Architecture Makefiles --- 6.1 Set variables to tweak the build to the architecture - --- 6.2 Add prerequisites to archprepare: - --- 6.3 List directories to visit when descending - --- 6.4 Architecture-specific boot images - --- 6.5 Building non-kbuild targets - --- 6.6 Commands useful for building a boot image - --- 6.7 Custom kbuild commands - --- 6.8 Preprocessing linker scripts - --- 6.9 Generic header files + --- 6.2 Add prerequisites to archheaders: + --- 6.3 Add prerequisites to archprepare: + --- 6.4 List directories to visit when descending + --- 6.5 Architecture-specific boot images + --- 6.6 Building non-kbuild targets + --- 6.7 Commands useful for building a boot image + --- 6.8 Custom kbuild commands + --- 6.9 Preprocessing linker scripts + --- 6.10 Generic header files === 7 Kbuild syntax for exported headers --- 7.1 header-y @@ -252,7 +253,7 @@ more details, with real examples. This will create a library lib.a based on delay.o. For kbuild to actually recognize that there is a lib.a being built, the directory shall be listed in libs-y. - See also "6.3 List directories to visit when descending". + See also "6.4 List directories to visit when descending". Use of lib-y is normally restricted to lib/ and arch/*/lib. @@ -974,7 +975,20 @@ When kbuild executes, the following steps are followed (roughly): $(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic mode) if this option is supported by $(AR). ---- 6.2 Add prerequisites to archprepare: +--- 6.2 Add prerequisites to archheaders: + + The archheaders: rule is used to generate header files that + may be installed into user space by "make header_install" or + "make headers_install_all". In order to support + "make headers_install_all", this target has to be able to run + on an unconfigured tree, or a tree configured for another + architecture. + + It is run before "make archprepare" when run on the + architecture itself. + + +--- 6.3 Add prerequisites to archprepare: The archprepare: rule is used to list prerequisites that need to be built before starting to descend down in the subdirectories. @@ -990,7 +1004,7 @@ When kbuild executes, the following steps are followed (roughly): generating offset header files. ---- 6.3 List directories to visit when descending +--- 6.4 List directories to visit when descending An arch Makefile cooperates with the top Makefile to define variables which specify how to build the vmlinux file. Note that there is no @@ -1019,7 +1033,7 @@ When kbuild executes, the following steps are followed (roughly): drivers-$(CONFIG_OPROFILE) += arch/sparc64/oprofile/ ---- 6.4 Architecture-specific boot images +--- 6.5 Architecture-specific boot images An arch Makefile specifies goals that take the vmlinux file, compress it, wrap it in bootstrapping code, and copy the resulting files @@ -1070,7 +1084,7 @@ When kbuild executes, the following steps are followed (roughly): When "make" is executed without arguments, bzImage will be built. ---- 6.5 Building non-kbuild targets +--- 6.6 Building non-kbuild targets extra-y @@ -1090,7 +1104,7 @@ When kbuild executes, the following steps are followed (roughly): shall be built, but shall not be linked as part of built-in.o. ---- 6.6 Commands useful for building a boot image +--- 6.7 Commands useful for building a boot image Kbuild provides a few macros that are useful when building a boot image. @@ -1112,7 +1126,7 @@ When kbuild executes, the following steps are followed (roughly): always be built. Assignments to $(targets) are without $(obj)/ prefix. if_changed may be used in conjunction with custom commands as - defined in 6.7 "Custom kbuild commands". + defined in 6.8 "Custom kbuild commands". Note: It is a typical mistake to forget the FORCE prerequisite. Another common pitfall is that whitespace is sometimes @@ -1171,7 +1185,7 @@ When kbuild executes, the following steps are followed (roughly): $(obj)/%.dtb: $(src)/%.dts $(call cmd,dtc) ---- 6.7 Custom kbuild commands +--- 6.8 Custom kbuild commands When kbuild is executing with KBUILD_VERBOSE=0, then only a shorthand of a command is normally displayed. @@ -1198,7 +1212,7 @@ When kbuild executes, the following steps are followed (roughly): will be displayed with "make KBUILD_VERBOSE=0". ---- 6.8 Preprocessing linker scripts +--- 6.9 Preprocessing linker scripts When the vmlinux image is built, the linker script arch/$(ARCH)/kernel/vmlinux.lds is used. @@ -1228,7 +1242,7 @@ When kbuild executes, the following steps are followed (roughly): The kbuild infrastructure for *lds file are used in several architecture-specific files. ---- 6.9 Generic header files +--- 6.10 Generic header files The directory include/asm-generic contains the header files that may be shared between individual architectures. -- cgit v1.2.3