linux/scripts/Makefile.build, branch v4.15

Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-01-17T19:54:56Z

Pull x86 pti bits and fixes from Thomas Gleixner: "This last update contains: - An objtool fix to prevent a segfault with the gold linker by changing the invocation order. That's not just for gold, it's a general robustness improvement. - An improved error message for objtool which spares tearing hairs. - Make KASAN fail loudly if there is not enough memory instead of oopsing at some random place later - RSB fill on context switch to prevent RSB underflow and speculation through other units. - Make the retpoline/RSB functionality work reliably for both Intel and AMD - Add retpoline to the module version magic so mismatch can be detected - A small (non-fix) update for cpufeatures which prevents cpu feature clashing for the upcoming extra mitigation bits to ease backporting" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: module: Add retpoline tag to VERMAGIC x86/cpufeature: Move processor tracing out of scattered features objtool: Improve error message for bad file argument objtool: Fix seg fault with gold linker x86/retpoline: Add LFENCE to the retpoline/RSB filling RSB macros x86/retpoline: Fill RSB on context switch for affected CPUs x86/kasan: Panic if there is not enough memory to boot

objtool: Fix seg fault with gold linker

2018-01-16T00:27:27Z

Objtool segfaults when the gold linker is used with CONFIG_MODVERSIONS=y and CONFIG_UNWINDER_ORC=y. With CONFIG_MODVERSIONS=y, the .o file gets passed to the linker before being passed to objtool. The gold linker seems to strip unused ELF symbols by default, which confuses objtool and causes the seg fault when it's trying to generate ORC metadata. Objtool should really be running immediately after GCC anyway, without a linker call in between. Change the makefile ordering so that objtool is called before the linker. Reported-and-tested-by: Markus Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Link: http://lkml.kernel.org/r/355f04da33581f4a3bf82e5b512973624a1e23a2.1516025651.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar

Merge commit 'upstream-x86-entry' into WIP.x86/mm

2017-12-17T11:58:53Z

Pull in a minimal set of v4.15 entry code changes, for a base for the MM isolation patches. Signed-off-by: Ingo Molnar

Merge tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2017-11-25T18:06:30Z

Pull more Kbuild updates from Masahiro Yamada: - use 'pwd' instead of '/bin/pwd' for portability - clean up Makefiles - fix ld-option for clang - fix malloc'ed data size in Kconfig - fix parallel building along with coccicheck - fix a minor issue of package building - prompt to use "rpm-pkg" instead of "rpm" - clean up *.i and *.lst patterns by "make clean" * tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: drop $(extra-y) from real-objs-y kbuild: clean up *.i and *.lst patterns by make clean kbuild: rpm: prompt to use "rpm-pkg" if "rpm" target is used kbuild: pkg: use --transform option to prefix paths in tar coccinelle: fix parallel build with CHECK=scripts/coccicheck kconfig/symbol.c: use correct pointer type argument for sizeof kbuild: Set KBUILD_CFLAGS before incl. arch Makefile kbuild: remove all dummy assignments to obj- kbuild: create built-in.o automatically if parent directory wants it kbuild: /bin/pwd -> pwd

Merge tag 'docs-4.15-2' of git://git.lwn.net/linux

2017-11-24T07:01:32Z

Pull documentation updates from Jonathan Corbet: "A few late-arriving docs updates that have no real reason to wait. There's a new "Co-Developed-by" tag described by Greg, and a build enhancement from Willy to generate docs warnings during a kernel build (but only when additional warnings have been requested in general)" * tag 'docs-4.15-2' of git://git.lwn.net/linux: Add optional check for bad kernel-doc comments Documentation: fix profile= options in kernel-parameters.txt documentation/svga.txt: update outdated file kokr/memory-barriers.txt: Fix typo in paring example kokr/memory-barriers/txt: Replace uses of "transitive" Documentation/process: add Co-Developed-by: tag for patches with multiple authors

Add optional check for bad kernel-doc comments

2017-11-20T19:09:11Z

Implement a '-none' output mode for kernel-doc which will only output warning messages, and suppresses the warning message about there being no kernel-doc in the file. If the build has requested additional warnings, automatically check all .c files. This patch does not check .h files. Enabling the warning by default would add about 1300 warnings, so it's default off for now. People who care can use this to check they didn't break the docs and maybe we'll get all the warnings fixed and be able to enable this check by default in the future. Signed-off-by: Matthew Wilcox Signed-off-by: Jonathan Corbet

kbuild: create built-in.o automatically if parent directory wants it

2017-11-18T02:38:58Z

"obj-y += foo/" syntax requires Kbuild to visit the "foo" subdirectory and link built-in.o from that directory. This means foo/Makefile is responsible for creating built-in.o even if there is no object to link (in this case, built-in.o is an empty archive). We have had several fixups like commit 4b024242e8a4 ("kbuild: Fix linking error built-in.o no such file or directory"), then ended up with a complex condition as follows: ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),) builtin-target := $(obj)/built-in.o endif We still have more cases not covered by the above, so we need to add obj- := dummy.o in several places just for creating empty built-in.o. A key point is, the parent Makefile knows whether built-in.o is needed or not. If a subdirectory needs to create built-in.o, its parent can tell the fact when descending. If non-empty $(need-builtin) flag is passed from the parent, built-in.o should be created. $(obj-y) should be still checked to support the single target "%/". All of ugly tricks will go away. Signed-off-by: Masahiro Yamada Reviewed-by: Sam Ravnborg

Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2017-11-18T01:45:29Z

Pull Kbuild updates from Masahiro Yamada: "One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation" * tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) kbuild: move coccicheck help from scripts/Makefile.help to top Makefile sh: decompressor: add shipped files to .gitignore frv: .gitignore: ignore vmlinux.lds selinux: remove unnecessary assignment to subdir- kbuild: specify FORCE in Makefile.headersinst as .PHONY target kbuild: remove redundant mkdir from ./Kbuild kbuild: optimize object directory creation for incremental build kbuild: create object directories simpler and faster kbuild: filter-out PHONY targets from "targets" kbuild: remove redundant $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...

kbuild: optimize object directory creation for incremental build

2017-11-16T00:07:36Z

The previous commit largely optimized the object directory creation. We can optimize it more for incremental build. There are already *.cmd files in the output directory. The existing *.cmd files have been picked up by $(wildcard ...). Obviously, directories containing them exist too, so we can skip "mkdir -p". With this, Kbuild runs almost zero "mkdir -p" in incremental building. Signed-off-by: Masahiro Yamada

kbuild: create object directories simpler and faster

2017-11-16T00:07:35Z

For the out-of-tree build, scripts/Makefile.build creates output directories, but this operation is not efficient. scripts/Makefile.lib calculates obj-dirs as follows: obj-dirs := $(dir $(multi-objs) $(obj-y)) Please notice $(sort ...) is not used here. Usually the result is as many "./" as objects here. For a lot of duplicated paths, the following command is invoked. _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) Then, the costly shell command is run over and over again. I see many points for optimization: [1] Use $(sort ...) to cut down duplicated paths before passing them to system call [2] Use single $(shell ...) instead of repeating it with $(foreach ...) This will reduce forking. [3] We can calculate obj-dirs more simply. Most of objects are already accumulated in $(targets). So, $(dir $(targets)) is fine and more comprehensive. I also removed ugly code in arch/x86/entry/vdso/Makefile. This is now really unnecessary. Signed-off-by: Masahiro Yamada Acked-by: Ingo Molnar Tested-by: Douglas Anderson