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2018-04-11Kbuild: fix # escaping in .cmd files for future MakeRasmus Villemoes
I tried building using a freshly built Make (4.2.1-69-g8a731d1), but already the objtool build broke with orc_dump.c: In function ‘orc_dump’: orc_dump.c:106:2: error: ‘elf_getshnum’ is deprecated [-Werror=deprecated-declarations] if (elf_getshdrnum(elf, &nr_sections)) { Turns out that with that new Make, the backslash was not removed, so cpp didn't see a #include directive, grep found nothing, and -DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS. Now, that new Make behaviour is documented in their NEWS file: * WARNING: Backward-incompatibility! Number signs (#) appearing inside a macro reference or function invocation no longer introduce comments and should not be escaped with backslashes: thus a call such as: foo := $(shell echo '#') is legal. Previously the number sign needed to be escaped, for example: foo := $(shell echo '\#') Now this latter will resolve to "\#". If you want to write makefiles portable to both versions, assign the number sign to a variable: C := \# foo := $(shell echo '$C') This was claimed to be fixed in 3.81, but wasn't, for some reason. To detect this change search for 'nocomment' in the .FEATURES variable. This also fixes up the two make-cmd instances to replace # with $(pound) rather than with \#. There might very well be other places that need similar fixup in preparation for whatever future Make release contains the above change, but at least this builds an x86_64 defconfig with the new make. Link: https://bugzilla.kernel.org/show_bug.cgi?id=197847 Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-03-26kbuild: move include/config/ksym/* to include/ksym/*Masahiro Yamada
The idea of using fixdep was inspired by Kconfig, but autoksyms belongs to a different group. So, I want to move those touched files under include/config/ksym/ to include/ksym/. The directory include/ksym/ can be removed by 'make clean' because it is meaningless for the external module building. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicolas Pitre <nico@linaro.org>
2018-03-26kbuild: simplify ld-option implementationMasahiro Yamada
Currently, linker options are tested by the coordination of $(CC) and $(LD) because $(LD) needs some object to link. As commit 86a9df597cdd ("kbuild: fix linker feature test macros when cross compiling with Clang") addressed, we need to make sure $(CC) and $(LD) agree the underlying architecture of the passed object. This could be a bit complex when we combine tools from different groups. For example, we can use clang for $(CC), but we still need to rely on GCC toolchain for $(LD). So, I was searching for a way of standalone testing of linker options. A trick I found is to use '-v'; this not only prints the version string, but also tests if the given option is recognized. If a given option is supported, $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419 GNU ld (Linaro_Binutils-2017.11) 2.28.2.20170706 $ echo $? 0 If unsupported, $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419 GNU ld (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) 2.23.1 aarch64-linux-gnu-ld: unrecognized option '--fix-cortex-a53-843419' aarch64-linux-gnu-ld: use the --help option for usage information $ echo $? 1 Gold works likewise. $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-843419 GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14 masahiro@pug:~/ref/linux$ echo $? 0 $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-999999 GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14 aarch64-linux-gnu-ld.gold: --fix-cortex-a53-999999: unknown option aarch64-linux-gnu-ld.gold: use the --help option for usage information $ echo $? 1 LLD too. $ ld.lld -v --gc-sections LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 0 $ ld.lld -v --fix-cortex-a53-843419 LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 0 $ ld.lld -v --fix-cortex-a53-999999 ld.lld: error: unknown argument: --fix-cortex-a53-999999 LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 1 Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
2018-03-26kbuild: Improve portability of some sed invocationsMichael Forney
* Use BREs where EREs aren't necessary. * Pass -E instead of -r to use EREs. This will be standardized in the next POSIX revision[0]. GNU sed supports this since 4.2 (May 2009), and busybox since 1.22.0 (Jan 2014). * Use the [:space:] character class instead of ` \t` in bracket expressions. In bracket expressions, POSIX says that <backslash> loses its special meaning, so a conforming implementation cannot expand \t to <tab>[1]. * In BREs, use interval expressions (\{n,m\}) instead of non-standard features like \+ and \?. * Use a loop instead of -s flag. There are still plenty of other cases of non-standard sed invocations (use of ERE features in BREs, in-place editing), but this fixes some core ones. [0] http://austingroupbugs.net/view.php?id=528 [1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05 Signed-off-by: Michael Forney <forney@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-16kbuild: create directory for make cache only when necessaryMasahiro Yamada
Currently, the existence of $(dir $(make-cache)) is always checked, and created if it is missing. We can avoid unnecessary system calls by some tricks. [1] If KBUILD_SRC is unset, we are building in the source tree. The output directory checks can be entirely skipped. [2] If at least one cache data is found, it means the cache file was included. Obviously its directory exists. Skip "mkdir -p". [3] If Makefile does not contain any call of __run-and-store, it will not create a cache file. No need to create its directory. [4] The "mkdir -p" should be only invoked by the first call of __run-and-store Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Douglas Anderson <dianders@chromium.org>
2017-11-13kbuild: fix linker feature test macros when cross compiling with ClangNick Desaulniers
I was not seeing my linker flags getting added when using ld-option when cross compiling with Clang. Upon investigation, this seems to be due to a difference in how GCC vs Clang handle cross compilation. GCC is configured at build time to support one backend, that is implicit when compiling. Clang is explicit via the use of `-target <triple>` and ships with all supported backends by default. GNU Make feature test macros that compile then link will always fail when cross compiling with Clang unless Clang's triple is passed along to the compiler. For example: $ clang -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: unknown architecture of input file `temp.o' is incompatible with aarch64 output aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 0000000000400078 $ echo $? 1 $ clang -target aarch64-linux-android- -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 00000000004002e4 $ echo $? 0 This causes conditional checks that invoke $(CC) without the target triple, then $(LD) on the result, to always fail. Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-13kbuild: shrink .cache.mk when it exceeds 1000 linesMasahiro Yamada
The cache files are only cleaned away by "make clean". If you continue incremental builds, the cache files will grow up little by little. It is not a big deal in general use cases because compiler flags do not change quite often. However, if you do build-test for various architectures, compilers, and kernel configurations, you will end up with huge cache files soon. When the cache file exceeds 1000 lines, shrink it down to 500 by "tail". The Least Recently Added lines are cut. (not Least Recently Used) I hope it will work well enough. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Douglas Anderson <dianders@chromium.org>
2017-11-13kbuild: Add a cache for generated variablesDouglas Anderson
While timing a "no-op" build of the kernel (incrementally building the kernel even though nothing changed) in the Chrome OS build system I found that it was much slower than I expected. Digging into things a bit, I found that quite a bit of the time was spent invoking the C compiler even though we weren't actually building anything. Currently in the Chrome OS build system the C compiler is called through a number of wrappers (one of which is written in python!) and can take upwards of 100 ms to invoke even if we're not doing anything difficult, so these invocations of the compiler were taking a lot of time. Worse the invocations couldn't seem to take advantage of the multiple cores on my system. Certainly it seems like we could make the compiler invocations in the Chrome OS build system faster, but only to a point. Inherently invoking a program as big as a C compiler is a fairly heavy operation. Thus even if we can speed the compiler calls it made sense to track down what was happening. It turned out that all the compiler invocations were coming from usages like this in the kernel's Makefile: KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) Due to the way cc-option and similar statements work the above contains an implicit call to the C compiler. ...and due to the fact that we're storing the result in KBUILD_CFLAGS, a simply expanded variable, the call will happen every time the Makefile is parsed, even if there are no users of KBUILD_CFLAGS. Rather than redoing this computation every time, it makes a lot of sense to cache the result of all of the Makefile's compiler calls just like we do when we compile a ".c" file to a ".o" file. Conceptually this is quite a simple idea. ...and since the calls to invoke the compiler and similar tools are centrally located in the Kbuild.include file this doesn't even need to be super invasive. Implementing the cache in a simple-to-use and efficient way is not quite as simple as it first sounds, though. To get maximum speed we really want the cache in a format that make can natively understand and make doesn't really have an ability to load/parse files. ...but make _can_ import other Makefiles, so the solution is to store the cache in Makefile format. This requires coming up with a valid/unique Makefile variable name for each value to be cached, but that's solvable with some cleverness. After this change, we'll automatically create a ".cache.mk" file that will contain our cached variables. We'll load this on each invocation of make and will avoid recomputing anything that's already in our cache. The cache is stored in a format that it shouldn't need any invalidation since anything that might change should affect the "key" and any old cached value won't be used. Signed-off-by: Douglas Anderson <dianders@chromium.org> Tested-by: Ingo Molnar <mingo@kernel.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-08-10kbuild: trivial cleanups on the commentsCao jin
This is a bunch of trivial fixes and cleanups. Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-25kbuild: Add __cc-option macroMatthias Kaehlcke
cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-25kbuild: remove cc-option-alignMasahiro Yamada
Documentation/kbuild/makefiles.txt says the change for align options occurred at GCC 3.0, and Documentation/process/changes.rst says the minimal supported GCC version is 3.2, so it should be safe to hard-code -falign* options. Fix the only user arch/x86/Makefile_32.cpu and remove cc-option-align. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ingo Molnar <mingo@kernel.org>
2017-05-10Merge tag 'kbuild-v4.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - improve Clang support - clean up various Makefiles - improve build log visibility (objtool, alpha, ia64) - improve compiler flag evaluation for better build performance - fix GCC version-dependent warning - fix genksyms * tag 'kbuild-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (23 commits) kbuild: dtbinst: remove unnecessary __dtbs_install_prep target ia64: beatify build log for gate.so and gate-syms.o alpha: make short build log available for division routines alpha: merge build rules of division routines alpha: add $(src)/ rather than $(obj)/ to make source file path Makefile: evaluate LDFLAGS_BUILD_ID only once objtool: make it visible in make V=1 output kbuild: clang: add -no-integrated-as to KBUILD_[AC]FLAGS kbuild: Add support to generate LLVM assembly files kbuild: Add better clang cross build support kbuild: drop -Wno-unknown-warning-option from clang options kbuild: fix asm-offset generation to work with clang kbuild: consolidate redundant sed script ASM offset generation frv: Use OFFSET macro in DEF_*REG() kbuild: avoid conflict between -ffunction-sections and -pg on gcc-4.7 kbuild: Consolidate header generation from ASM offset information kbuild: use -Oz instead of -Os when using clang kbuild, LLVMLinux: Add -Werror to cc-option to support clang Kbuild: make designated_init attribute fatal kbuild: drop unneeded patterns '.*.orig' and '.*.rej' from distclean ...
2017-04-12kbuild, LLVMLinux: Add -Werror to cc-option to support clangMark Charlebois
Clang will warn about unknown warnings but will not return false unless -Werror is set. GCC will return false if an unknown warning is passed. Adding -Werror make both compiler behave the same. [arnd: it turns out we need the same patch for testing whether -ffunction-sections works right with gcc. I've build tested extensively with this patch applied, so let's just merge this one now.] Signed-off-by: Mark Charlebois <charlebm@gmail.com> Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-03-30x86/build: Mostly disable '-maccumulate-outgoing-args'Josh Poimboeuf
The GCC '-maccumulate-outgoing-args' flag is enabled for most configs, mostly because of issues which are no longer relevant. For most configs, and with most recent versions of GCC, it's no longer needed. Clarify which cases need it, and only enable it for those cases. Also produce a compile-time error for the ftrace graph + mcount + '-Os' case, which will otherwise cause runtime failures. The main benefit of '-maccumulate-outgoing-args' is that it prevents an ugly prologue for functions which have aligned stacks. But removing the option also has some benefits: more readable argument saves, smaller text size, and (presumably) slightly improved performance. Here are the object size savings for 32-bit and 64-bit defconfig kernels: text data bss dec hex filename 10006710 3543328 1773568 15323606 e9d1d6 vmlinux.x86-32.before 9706358 3547424 1773568 15027350 e54c96 vmlinux.x86-32.after text data bss dec hex filename 10652105 4537576 843776 16033457 f4a6b1 vmlinux.x86-64.before 10639629 4537576 843776 16020981 f475f5 vmlinux.x86-64.after That comes out to a 3% text size improvement on x86-32 and a 0.1% text size improvement on x86-64. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170316193133.zrj6gug53766m6nn@treble Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-14Kbuild: Add cpp_its_S in ksym_dep_filterMarcin Nowakowski
Add a new command cpp_its_S introduced in commit cf2a5e0bb4c6 ("MIPS: Support generating Flattened Image Trees (.itb)") to ksym_dep_filter handler - otherwise a warning is produced during the build of MIPS platforms (when vmlinux.*.itb target is chosen). Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: Michal Marek <mmarek@suse.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15278/ Signed-off-by: James Hogan <james.hogan@imgtec.com>
2016-08-08kbuild: no gcc-plugins during cc-option testsEmese Revfy
The gcc-plugins arguments should not be included when performing cc-option tests. Steps to reproduce: 1) make mrproper 2) make defconfig 3) enable GCC_PLUGINS, GCC_PLUGIN_CYC_COMPLEXITY 4) enable FUNCTION_TRACER (it will select other options as well) 5) make && make modules Build errors: MODPOST 18 modules ERROR: "__fentry__" [net/netfilter/xt_nat.ko] undefined! ERROR: "__fentry__" [net/netfilter/xt_mark.ko] undefined! ERROR: "__fentry__" [net/netfilter/xt_addrtype.ko] undefined! ERROR: "__fentry__" [net/netfilter/xt_LOG.ko] undefined! ERROR: "__fentry__" [net/netfilter/nf_nat_sip.ko] undefined! ERROR: "__fentry__" [net/netfilter/nf_nat_irc.ko] undefined! ERROR: "__fentry__" [net/netfilter/nf_nat_ftp.ko] undefined! ERROR: "__fentry__" [net/netfilter/nf_nat.ko] undefined! Reported-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: renamed variable, clarified commit message] Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-18Kbuild: don't add obj tree in additional includesArnd Bergmann
When building with separate object directories and driver specific Makefiles that add additional header include paths, Kbuild adjusts the gcc flags so that we include both the directory in the source tree and in the object tree. However, due to another bug I fixed earlier, this did not actually include the correct directory in the object tree, so we know that we only really need the source tree here. Also, including the object tree sometimes causes warnings about nonexisting directories when the include path only exists in the source. This changes the logic to only emit the -I argument for the srctree, not for objects. We still need both $(srctree)/$(src) and $(obj) though, so I'm adding them manually. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-07-18Kbuild: don't add ../../ to include pathArnd Bergmann
When we build with O=objdir and objdir is directly below the source tree, $(srctree) becomes '..'. When a Makefile adds a CFLAGS option like -Ipath/to/headers and we are building with a separate object directory, Kbuild tries to add two -I options, one for the source tree and one for the object tree. An absolute path is treated as a special case, and don't add this one twice. This also normally catches -I$(srctree)/$(src) as $(srctree) usually is an absolute directory like /home/arnd/linux/. The combination of the two behaviors however results in an invalid path name to be included: we get both ../$(src) and ../../$(src), the latter one pointing outside of the source tree, usually to a nonexisting directory. Building with 'make W=1' makes this obvious: cc1: error: ../../arch/arm/mach-s3c24xx/include: No such file or directory [-Werror=missing-include-dirs] This adds another special case, treating path names starting with ../ like those starting with / so we don't try to prefix that with $(srctree). Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-05-10kbuild: fix if_change and friends to consider argument orderMasahiro Yamada
Currently, arg-check is implemented as follows: arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ $(filter-out $(cmd_$@), $(cmd_$(1))) ) This does not care about the order of arguments that appear in $(cmd_$(1)) and $(cmd_$@). So, if_changed and friends never rebuild the target if only the argument order is changed. This is a problem when the link order is changed. Apparently, obj-y += foo.o obj-y += bar.o and obj-y += bar.o obj-y += foo.o should be distinguished because the link order determines the probe order of drivers. So, built-in.o should be rebuilt when the order of objects is changed. This commit fixes arg-check to compare the old/current commands including the argument order. Of course, this change has a side effect; Kbuild will react to the change of compile option order. For example, "-DFOO -DBAR" and "-DBAR -DFOO" should give no difference to the build result, but false positive should be better than false negative. I am moving space_escape to the top of Kbuild.include just for a matter of preference. In practical terms, space_escape can be defined after arg-check because arg-check uses "=" flavor, not ":=". Having said that, collecting convenient variables in one place makes sense from the point of readability. Chaining "%%%SPACE%%%" to "_-_SPACE_-_" is also a matter of taste at this point. Actually, it can be arbitrary as long as it is an unlikely used string. The only problem I see in "%%%SPACE%%%" is that "%" is a special character in "$(patsubst ...)" context. This commit just uses "$(subst ...)" for arg-check, but I am fixing it now in case we might want to use it in $(patsubst ...) context in the future. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-05-10kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same lineNicolas Pitre
In kernel/cgroup.c there is: #define SUBSYS(_x) \ DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_enabled_key); \ DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_on_dfl_key); \ EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_enabled_key); \ EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_on_dfl_key); The expansion of this macro causes multiple EXPORT_SYMBOL_GPL() instances to appear on the same preprocessor line output, confusing the sed script expecting only one of them per line. Unfortunately this can't be fixed nicely in the sed script as sed's regexp can't do non greedy matching. Fix this by turning any semicolon into a line break before filtering. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-04-27kbuild: adjust ksym_dep_filter for some cmd_* renamesNicolas Pitre
The following renames occurred recently: cmd_cc_i_c --> cmd_cpp_i_c cmd_as_s_S --> cmd_cpp_s_S The respective cc_*_c and as_*_S patterns no longer match the above therefore additional patterns are needed. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-03-29kbuild: add fine grained build dependencies for exported symbolsNicolas Pitre
Like with kconfig options, we now have the ability to compile in and out individual EXPORT_SYMBOL() declarations based on the content of include/generated/autoksyms.h. However we don't want the entire world to be rebuilt whenever that file is touched. Let's apply the same build dependency trick used for CONFIG_* symbols where the time stamp of empty files whose paths matching those symbols is used to trigger fine grained rebuilds. In our case the key is the symbol name passed to EXPORT_SYMBOL(). However, unlike config options, we cannot just use fixdep to parse the source code for EXPORT_SYMBOL(ksym) because several variants exist and parsing them all in a separate tool, and keeping it in synch, is not trivially maintainable. Furthermore, there are variants such as EXPORT_SYMBOL_GPL(pci_user_read_config_##size); that are instanciated via a macro for which we can't easily determine the actual exported symbol name(s) short of actually running the preprocessor on them. Storing the symbol name string in a special ELF section doesn't work for targets that output assembly or preprocessed source. So the best way is really to leverage the preprocessor by having it output actual symbol names anchored by a special sequence that can be easily filtered out. Then the list of symbols is simply fed to fixdep to be merged with the other dependencies. That implies the preprocessor is executed twice for each source file. A previous attempt relied on a warning pragma for each EXPORT_SYMBOL() instance that was filtered apart from stderr by the build system with a sed script during the actual compilation pass. Unfortunately the preprocessor/compiler diagnostic output isn't stable between versions and this solution, although more efficient, was deemed too fragile. Because of the lowercasing performed by fixdep, there might be name collisions triggering spurious rebuilds for similar symbols. But this shouldn't be a big issue in practice. (This is the case for CONFIG_* symbols and I didn't want to be different here, whatever the original reason for doing so.) To avoid needless build overhead, the exported symbol name gathering is performed only when CONFIG_TRIM_UNUSED_KSYMS is selected. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
2016-03-29kbuild: de-duplicate fixdep usageNicolas Pitre
The generation and postprocessing of automatic dependency rules is duplicated in rule_cc_o_c, rule_as_o_S and if_changed_dep. Since this is not a trivial one-liner action, it is now abstracted under cmd_and_fixdep to simplify things and make future changes in this area easier. In the rule_cc_o_c and rule_as_o_S cases that means the order of some commands has been altered, namely fixdep and related file manipulations are executed earlier, but they didn't depend on those commands that now execute later. Signed-off-by: Nicolas Pitre <nico@linaro.org>
2016-03-04kbuild: suppress annoying "... is up to date." messageMasahiro Yamada
Under certain conditions, Kbuild shows "... is up to date" where if_changed or friends are used. For example, the incremental build of ARM64 Linux shows this message when the kernel image has not been updated. $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh CHK include/generated/compile.h CHK kernel/config_data.h make[1]: `arch/arm64/boot/Image.gz' is up to date. Building modules, stage 2. MODPOST 0 modules The following is the build rule in arch/arm64/boot/Makefile: $(obj)/Image.gz: $(obj)/Image FORCE $(call if_changed,gzip) If the Image.gz is newer than the Image and the command line has not changed (i.e., $(any-prereq) and $(arg-check) are both empty), the build rule $(call if_changed,gzip) is evaluated to be empty, then GNU Make reports the target is up to date. In order to make GNU Make quiet, we need to give it something to do, for example, "@:". This should be fixed in the Kbuild core part rather than in each Makefile. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michal Marek <mmarek@suse.com>
2015-09-08Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull core kbuild updates from Michal Marek: - modpost portability fix - linker script fix - genksyms segfault fix - fixdep cleanup - fix for clang detection * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: Fix clang detection kbuild: fixdep: drop meaningless hash table initialization kbuild: fixdep: optimize code slightly genksyms: Regenerate parser genksyms: Duplicate function pointer type definitions segfault kbuild: Fix .text.unlikely placement Avoid conflict with host definitions when cross-compiling
2015-09-04kbuild: Fix clang detectionMichal Marek
We cannot detect clang before including the arch Makefile, because that can set the default cross compiler. We also cannot detect clang after including the arch Makefile, because powerpc wants to know about clang. Solve this by using an deferred variable. This costs us a few shell invocations, but this is only a constant number. Reported-by: Behan Webster <behanw@converseincode.com> Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2015-08-14modsign: Handle signing key in source treeDavid Woodhouse
Since commit 1329e8cc69 ("modsign: Extract signing cert from CONFIG_MODULE_SIG_KEY if needed"), the build system has carefully coped with the signing key being specified as a relative path in either the source or or the build trees. However, the actual signing of modules has not worked if the filename is relative to the source tree. Fix that by moving the config_filename helper into scripts/Kbuild.include so that it can be used from elsewhere, and then using it in the top-level Makefile to find the signing key file. Kill the intermediate $(MODPUBKEY) and $(MODSECKEY) variables too, while we're at it. There's no need for them. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
2015-01-09kbuild: allow cc-ifversion to have the argument for false conditionMasahiro Yamada
The macro "try-run" can have an argument for each of true and false cases. Having an argument for the false case of cc-ifversion (and ld-ifversion) would be useful too. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-01-09kbuild: do not add $(call ...) to invoke cc-version or cc-fullversionMasahiro Yamada
The macros cc-version, cc-fullversion and ld-version take no argument. It is not necessary to add $(call ...) to invoke them. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Acked-by: Helge Deller <deller@gmx.de> [parisc] Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-01-09kbuild: fix cc-ifversion macroMasahiro Yamada
The macro "cc-version" takes no argument. Drop $(CC) from the "cc-ifversion" definition. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-12-20Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: "Here are the kbuild changes for v3.19-rc1: - Cleanups and deduplication in the main Makefile and scripts/Makefile.* - Sort the output of *config targets in make help - Old <linux/version.h> is always removed to avoid a surprise during bisecting - Warning fix in kconfig" * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: remove redundant -rR flag of hdr-inst kbuild: Fix make help-<board series> on powerpc kbuild: Automatically remove stale <linux/version.h> file kconfig: Fix warning "‘jump’ may be used uninitialized" Makefile: sort list of defconfig targets in make help output kbuild: Remove duplicate $(cmd) definition in Makefile.clean kbuild: collect shorthands into scripts/Kbuild.include
2014-12-03kbuild: remove redundant -rR flag of hdr-instMasahiro Yamada
Passing -rR for "make headers_install" is redundant because the top Makefile has already set -rR to MAKEFLAGS. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-11-26kbuild: collect shorthands into scripts/Kbuild.includeMasahiro Yamada
The shorthand "clean" is defined in both the top Makefile and scripts/Makefile.clean. Likewise, the "hdr-inst" is defined in both the top Makefile and scripts/Makefile.headersinst. To reduce code duplication, this commit collects them into scripts/Kbuild.include like the "build" and "modbuiltin" shorthands. It requires scripts/Makefile.clean to include scripts/Kbuild.include, but its impact on the performance of "make clean" should be negligible. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-21dts, kbuild: Factor out dtbs install rules to Makefile.dtbinstRobert Richter
Move dtbs install rules to Makefile.dtbinst. This change is needed to implement support for dts vendor subdirs. The change makes Makefiles easier and smaller as no longer the dtbs_install rule needs to be defined. Another advantage is that install goals are not encoded in targets anymore (%.dtb_dtbinst_). Signed-off-by: Robert Richter <rrichter@cavium.com>
2014-10-02kbuild: simplify build, clean, modbuiltin shorthandsMasahiro Yamada
$(if $(KBUILD_SRC),$(srctree)/) was a useful strategy to omit a long absolute path for in-source-tree build prior to commit 890676c65d699db3ad82e7dddd0cf8fb449031af (kbuild: Use relative path when building in the source tree). Now $(srctree) is "." when building in the source tree. It would not be annoying to add "$(srctree)/" all the time. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-08-07kbuild: Fix handling of backslashes in *.cmd filesMichal Marek
Commit c353acba ("kbuild: make: fix if_changed when command contains backslashes") attempted to handle backslashes in *.cmd files, but it only handled double backslashes for some reason. Changing make-cmd to also handle single backslashes fixes rebuilds with dash, but it breaks bash again. The reason is that the two shells disagree about the interpretation of backslash sequences in the echo builtin. The way out of this is to print the command with printf '%s\n'. While at it, document what the individual parts of make-cmd do and why. Reported-and-tested-by: Konstantin Khlebnikov <koct9i@gmail.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-04-07Merge branch 'kbuild' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild changes from Michal Marek: - cleanups in the main Makefiles and Documentation/DocBook/Makefile - make O=... directory is automatically created if needed - mrproper/distclean removes the old include/linux/version.h to make life easier when bisecting across the commit that moved the version.h file * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: docbook: fix the include error when executing "make help" kbuild: create a build directory automatically for out-of-tree build kbuild: remove redundant '.*.cmd' pattern from make distclean kbuild: move "quote" to Kbuild.include to be consistent kbuild: docbook: use $(obj) and $(src) rather than specific path kbuild: unconditionally clobber include/linux/version.h on distclean kbuild: docbook: specify KERNELDOC dependency correctly kbuild: docbook: include cmd files more simply kbuild: specify build_docproc as a phony target
2014-03-29kbuild: move "quote" to Kbuild.include to be consistentMasahiro Yamada
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-02-13Kbuild, lto: add ld-version and ld-ifversion macrosAndi Kleen
To check the linker version. Used by the LTO makefile. Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1391846481-31491-9-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-04-08kbuild: fix ld-option functionAntony Pavlov
The kbuild's ld-option function is broken because the command $(CC) /dev/null -c -o "$$TMPO" does not create object file! I have used a relatively old mips gcc 3.4.6 cross-compiler and a relatively new gcc 4.7.2 to check this fact but the results are the same. EXAMPLE: $ rm /tmp/1.o $ mips-linux-gcc /dev/null -c -o /tmp/1.o mips-linux-gcc: /dev/null: linker input file unused because linking not done $ ls -la /tmp/1.o ls: cannot access /tmp/1.o: No such file or directory We can easily fix the problem by adding the '-x c' compiler option. EXAMPLE: $ rm /tmp/1.o $ mips-linux-gcc -x c /dev/null -c -o /tmp/1.o $ ls -la /tmp/1.o -rw-r--r-- 1 antony antony 778 Apr 2 20:40 /tmp/1.o Also fix wrong ld-option example. Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2012-10-08Merge branch 'rc-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild fixes from Michal Marek: "Here are two fixes I intended to send after v3.6-rc7, but failed to do so. So please pull them for v3.7-rc1 and they will be picked up by stable. The first one fixes gcc -x <language> syntax in various build-time tests, which icecream and possible other gcc wrappers did not understand (and yes, icecream is going to be fixed as well). The second one fixes make tar-pkg so that unpacking the tarball does not replace the /lib -> /usr/lib symlink on recent Fedora releases." * 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: Fix gcc -x syntax kbuild: Do not package /boot and /lib in make tar-pkg
2012-10-06kbuild: make: fix if_changed when command contains backslashesSascha Hauer
The call if_changed mechanism does not work when the command contains backslashes. This basically is an issue with lzo and bzip2 compressed kernels. The compressed binaries do not contain the uncompressed image size, so these use size_append to append the size. This results in backslashes in the executed command. With this if_changed always detects a change in the command and rebuilds the compressed image even if nothing has changed. Fix this by escaping backslashes in make-cmd Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Jan Luebbe <jlu@pengutronix.de> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Bernhard Walle <bernhard@bwalle.de> Cc: Michal Marek <mmarek@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-03kbuild: Fix gcc -x syntaxJean Delvare
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect. This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations. Besides me, credits go to Michael Matz and Dirk Mueller for investigating the miscompilation issue and tracking it down to this incorrect -x parameter syntax. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Cc: Bernhard Walle <bernhard@bwalle.de> Cc: Michal Marek <mmarek@suse.cz> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
2012-03-24scripts/Kbuild.include: Fix portability problem of "echo -e"Bernhard Walle
"echo -e" is a GNU extension. When cross-compiling the kernel on a BSD-like operating system (Mac OS X in my case), this doesn't work. One could install a GNU version of echo, put that in the $PATH before the system echo and use "/usr/bin/env echo", but the solution with printf is simpler. Since it is no disadvantage on Linux, I hope that gets accepted even if cross-compiling the Linux kernel on another Unix operating system is quite a rare use case. Signed-off-by: Bernhard Walle <bernhard@bwalle.de> Andreas Bießmann <andreas@biessmann.de> Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-06-09kbuild: add `baseprereq'Arnaud Lacombe
On the same model as `basetarget', it represents the filename of first prerequisite with directory and extension stripped. Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
2011-05-16kbuild: make KBUILD_NOCMDDEP=1 handle empty built-in.oMichal Marek
Based on a patch by Rabin Vincent. Fix building with KBUILD_NOCMDDEP=1, which currently does not work because it does not build built-in.o with no dependencies: LD fs/notify/built-in.o ld: cannot find fs/notify/dnotify/built-in.o: No such file or directory ld: cannot find fs/notify/inotify/built-in.o: No such file or directory ld: cannot find fs/notify/fanotify/built-in.o: No such file or directory Reported-and-tested-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-05-03kbuild: Fix passing -Wno-* options to gcc 4.4+Michal Marek
Starting with 4.4, gcc will happily accept -Wno-<anything> in the cc-option test and complain later when compiling a file that has some other warning. This rather unexpected behavior is intentional as per http://gcc.gnu.org/PR28322, so work around it by testing for support of the opposite option (without the no-). Introduce a new Makefile function cc-disable-warning that does this and update two uses of cc-option in the toplevel Makefile. Reported-and-tested-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-20kbuild: Fix build with binutils <= 2.19Michal Marek
The D option of ar is only available in newer versions. Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-12-12kbuild: generate modules.builtinMichal Marek
To make it easier for module-init-tools and scripts like mkinitrd to distinguish builtin and missing modules, install a modules.builtin file listing all builtin modules. This is done by generating an additional config file (tristate.conf) with tristate options set to uppercase 'Y' or 'M'. If we source that config file, the builtin modules appear in obj-Y. Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-10-11kbuild,scripts: use non-builtin echo for '-e'Amerigo Wang
Alek reported that on Ubuntu, where dash is used, 'echo -e' can't work, so let's use non-builtin echo in this case. Reported-by: Alek Du <alek.du@intel.com> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>