1. 03 Oct, 2018 1 commit
  2. 21 Feb, 2018 1 commit
    • Martin Kelly's avatar
      tools: fix cross-compile var clobbering · 7ed1c190
      Martin Kelly authored
      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.comSigned-off-by: default avatarMartin Kelly <martin@martingkelly.com>
      Acked-by: default avatarMark 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7ed1c190
  3. 26 Jul, 2017 2 commits
  4. 12 Sep, 2016 1 commit
  5. 23 Nov, 2015 1 commit