# git rev-parse -q --verify 5cf0fd591f2e7833405bdc7ce2176c3502e8a11e^{commit} 5cf0fd591f2e7833405bdc7ce2176c3502e8a11e already have revision, skipping fetch # git checkout -q -f -B kisskb 5cf0fd591f2e7833405bdc7ce2176c3502e8a11e # git clean -qxdf # < git log -1 # commit 5cf0fd591f2e7833405bdc7ce2176c3502e8a11e # Author: Linus Torvalds # Date: Tue Feb 23 12:21:58 2021 -0800 # # Kbuild: disable TRIM_UNUSED_KSYMS option # # The removal of EXPORT_UNUSED_SYMBOL() in commit 367948220fce looks like # (and was sold as) a no-op, but it actually had a rather serious and # subtle side effect: the UNUSED_SYMBOLS option not only enabled the # removed (unused) functionality, it also _disabled_ the TRIM_UNUSED_KSYMS # functionality. # # And it turns out that TRIM_UNUSED_KSYMS is a huge time waste, and takes # up a third of the kernel build time for me. For no actual upside, since # no distro is likely to ever be able to enable it (because they all # support external kernel modules). # # Rather than re-enable EXPORT_UNUSED_SYMBOL, this just disables the # TRIM_UNUSED_KSYMS option by marking it broken. I'm tempted to just # remove the support entirely, but maybe somebody has a use-case and can # fix the behavior of it. # # I could have just disabled it for COMPILE_TEST, but it really smells # like the TRIM_UNUSED_KSYMS option is badly done and not really useful, # so this takes the more direct approach - let's see if anybody ever # actually notices or complains. # # Cc: Miroslav Benes # Cc: Emil Velikov # Cc: Christoph Hellwig # Cc: Jessica Yu # Fixes: 367948220fce ("module: remove EXPORT_UNUSED_SYMBOL*") # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld --version # < git log --format=%s --max-count=1 5cf0fd591f2e7833405bdc7ce2176c3502e8a11e # < make -s -j 10 ARCH=arm O=/kisskb/build/linus_tegra_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- tegra_defconfig # < make -s -j 10 ARCH=arm O=/kisskb/build/linus_tegra_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- help # make -s -j 10 ARCH=arm O=/kisskb/build/linus_tegra_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- olddefconfig # make -s -j 10 ARCH=arm O=/kisskb/build/linus_tegra_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- In file included from /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/tm.h:23, from /kisskb/src/scripts/gcc-plugins/gcc-common.h:15, from /kisskb/src/scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3: /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/config/elfos.h:102:21: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\ ^ /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/config/elfos.h:170:24: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ In file included from /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/tm.h:44, from /kisskb/src/scripts/gcc-plugins/gcc-common.h:15, from /kisskb/src/scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3: /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.4/plugin/include/defaults.h:126:24: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ cc1plus: warning: unrecognized command line option '-Wno-format-diag' Completed OK # rm -rf /kisskb/build/linus_tegra_defconfig_arm-gcc4.9 # Build took: 0:03:28.017335