Messages in this thread | | | Subject | Re: Kbuild: CC= handling broken for tools/ | From | Michal Marek <> | Date | Fri, 11 Nov 2016 13:38:00 +0100 |
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On 2016-11-11 12:23, Jiri Slaby wrote: > Hi, > > I am trying a new gcc with new warnings enabled: > > make O=../a/gcc7/ CC='gcc-7' V=1 kernel/exit.o > EXTRA_CFLAGS='-Wimplicit-fallthrough=3'
Note that EXTRA_CFLAGS is a makefile variable read by both kbuild and tools/build apparently.
> > But the build fails when building under tools/: [...] > gcc: error: unrecognized command line option ‘-Wimplicit-fallthrough=3’; > did you mean ‘-Wno-fallthrough’? > > > Apparently, CC is not respected for tools/ dir.
Jiri can better explain the behavior of the tools/ Makefiles, but if you want to use extra flags for kernel compilation, you should be using the KCFLAGS variable (see Documentation/kbuild/kbuild.txt).
Michal
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