path: root/tools/scripts
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authorMartin Kelly <martin@martingkelly.com>2018-02-21 14:45:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-21 15:35:42 -0800
commit7ed1c1901fe52e6c5828deb155920b44b0adabb1 (patch)
tree99b83707982b568e0e1d22ad35546fa69662a929 /tools/scripts
parentMerge tag 'leds_for-4.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds (diff)
tools: fix cross-compile var clobbering
Currently a number of Makefiles break when used with toolchains that pass extra flags in CC and other cross-compile related variables (such as --sysroot). Thus we get this error when we use a toolchain that puts --sysroot in the CC var: ~/src/linux/tools$ make iio [snip] iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory #include <unistd.h> ^~~~~~~~~~ This occurs because we clobber several env vars related to cross-compiling with lines like this: CC = $(CROSS_COMPILE)gcc Although this will point to a valid cross-compiler, we lose any extra flags that might exist in the CC variable, which can break toolchains that rely on them (for example, those that use --sysroot). This easily shows up using a Yocto SDK: $ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi $ echo $CC arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a8 --sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi $ echo $CROSS_COMPILE arm-poky-linux-gnueabi- $ echo ${CROSS_COMPILE}gcc krm-poky-linux-gnueabi-gcc Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the --sysroot and other flags that enable us to find the right libraries to link against, so we can't find unistd.h and other libraries and headers. Normally with the --sysroot flag we would find unistd.h in the sdk directory in the sysroot: $ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h' [snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not already set, and it compiles correctly with the above toolchain. So, generalize the logic that perf uses in the common Makefile and remove the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile. Note that this patch does not fix cross-compile for all the tools (some have other bugs), but it does fix it for all except usb and acpi, which still have other unrelated issues. I tested both with and without the patch on native and cross-build and there appear to be no regressions. Link: http://lkml.kernel.org/r/20180107214028.23771-1-martin@martingkelly.com Signed-off-by: Martin Kelly <martin@martingkelly.com> Acked-by: Mark Brown <broonie@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Jonathan Cameron <jic23@kernel.org> Cc: Pali Rohar <pali.rohar@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Robert Moore <robert.moore@intel.com> Cc: Lv Zheng <lv.zheng@intel.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Valentina Manea <valentina.manea.m@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'tools/scripts')
1 files changed, 18 insertions, 0 deletions
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index fcb3ed0be5f8..dd614463d4d6 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat
CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
+# Makefiles suck: This macro sets a default value of $(2) for the
+# variable named by $(1), unless the variable has been set by
+# environment or command line. This is necessary for CC and AR
+# because make sets default values, so the simpler ?= approach
+# won't work as expected.
+define allow-override
+ $(if $(or $(findstring environment,$(origin $(1))),\
+ $(findstring command line,$(origin $(1)))),,\
+ $(eval $(1) = $(2)))
+# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+$(call allow-override,CXX,$(CROSS_COMPILE)g++)
+$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
ifeq ($(CC_NO_CLANG), 1)
EXTRA_WARNINGS += -Wstrict-aliasing=3