Hi Alexey. 2018-09-12 21:08 GMT+09:00 Alexey Brodkin <Alexey.Brodkin@xxxxxxxxxxxx>: > Hello Masahiro-san, > > Starting from kernel v4.17 it is no longer possible to install kernel headers > for ARC architecture if there's no cross-toolchain in PATH. Really? I can do 'make ARCH=arc headers_install' with the latest Linus' tree. I see the following warnings, but possible to install kernel headers. ./scripts/gcc-version.sh: line 26: arc-linux-gcc: command not found ./scripts/gcc-version.sh: line 27: arc-linux-gcc: command not found If ARC compiler is not found in PATH, those warnings are displayed with v4.16 or older as well. I do not see much difference in the behavior. I am trying to fix even those warnings by eliminating unneeded compiler invocation. It is WIP. > Note installation of headers is just one of use-cases when we might not > have cross-tools available but still want to run "make xxx_defconfig". > I.e. the problem is "make xxx_defconfig" with no cross-toolchain. > > That's what I see: > ----------------------------->8-------------------------- > ./scripts/gcc-version.sh: line 26: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 27: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 26: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 27: arc-linux-gcc: command not found > make: arc-linux-gcc: Command not found > /bin/sh: arc-linux-gcc: command not found > /bin/sh: arc-linux-gcc: command not found > *** Default configuration is based on 'nsim_700_defconfig' > ./scripts/gcc-version.sh: line 26: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 27: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 29: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 26: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 27: arc-linux-gcc: command not found > ./scripts/gcc-version.sh: line 29: arc-linux-gcc: command not found > init/Kconfig:17: syntax error > init/Kconfig:16: invalid option > ./scripts/clang-version.sh: line 15: arc-linux-gcc: command not found > ./scripts/gcc-plugin.sh: line 11: arc-linux-gcc: command not found > make[1]: *** [scripts/kconfig/Makefile:91: defconfig] Error 1 > make: *** [Makefile:531: defconfig] Error 2 > ----------------------------->8-------------------------- > > That doesn't happen for ARM and other arches simply because for ARC > we define CROSS_COMPILE if it is not set by user, see: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arc/Makefile#n9 I do not think it is a good practice to forcibly set CROSS_COMPILE that users may not have. arch/m68k/Makefile uses cc-cross-prefix helper to set the first found compiler. > Still if CROSS_COMPILE is set before execution of "make defconfig" > then the same problem happens for others. > > I was able to find a series of commits which cause this problem, > here they are: > ----------------------------->8-------------------------- > 59f53855babf - gcc-plugins: test plugin support in Kconfig and clean up Makefile > 469cb7376c06 - kconfig: add CC_IS_CLANG and CLANG_VERSION > a4353898980c - kconfig: add CC_IS_GCC and GCC_VERSION > ----------------------------->8-------------------------- > > What happen is "$(CC)" is passed as an argument and in its turn CC is > "$(CROSS_COMPILE)gcc", see: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile#n385 > > > So if I substitute "CC" with "HOSTCC" in a couple of places (see below) > the problem goes away. But I'm not really sure if what I do is correct. > I.e. when we're interested in CC for target and when only host CC is of > our interest. I think the log of commit 316d55d55f49eca44 is a good source to know the background of this change. Now Kconfig requires the target compiler. So, it does not make sense to do defconfig with non-existing compiler. > Would be interesting to know your opinion here. I'd recommend to not hard-code CROSS_COMPILE. Thanks. -- Best Regards Masahiro Yamada
