Messages in this thread | | | Date | Mon, 22 Jun 2015 15:09:42 -0400 | From | Paul Gortmaker <> | Subject | Re: [PATCH] Documentation/vDSO: don't build tests when cross compiling |
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[Re: [PATCH] Documentation/vDSO: don't build tests when cross compiling] On 22/06/2015 (Mon 10:01) Andy Lutomirski wrote:
> On Mon, Jun 22, 2015 at 9:41 AM, Jonathan Corbet <corbet@lwn.net> wrote: > > On Sat, 20 Jun 2015 21:10:28 -0400 > > Paul Gortmaker <paul.gortmaker@windriver.com> wrote: > > > >> The following was seen in linux-next build coverage, which is somewhat > >> unique since it uses powerpc host to cross compile x86: > >> > >> Documentation/vDSO/vdso_standalone_test_x86.c:49:2: error: impossible > >> register constraint in 'asm' > >> make[4]: *** [Documentation/vDSO/vdso_standalone_test_x86.o] Error 1 > >> > >> It probably makes sense to just skip building these tests when > >> we are cross compiling. > > > > So I guess I'm not totally averse to applying these; getting rid of build > > errors is a good thing. But I do get the feeling like it's papering over > > the real problem. As a general rule, cross-compiling works; what's > > special about these programs that makes it fail? > > Agreed. What gcc version is this?
Just to re-iterate, this is ppc host, cross compiling x86_64 target.
The linux-next build I saw the errors in this weekend is here:
http://kisskb.ellerman.id.au/kisskb/buildresult/12445538/
According to that, it is gcc 4.6.3
It seems that the assumption is that nobody cross compiles x86, so when people see CONFIG_X86_64 set, they assume HOSTCC can create x86 binaries and will do so by default. Hence the breakdown in creation of some of these sample programs. We've already a similar fix in mainline in e9107f88c985bc ("samples/seccomp/Makefile: do not build tests if cross-compiling for MIPS")
I've added linux-next folks to Cc: -- probably should have done that on the original send... they know more about the toolchains used for -next.
Paul. --
> > --Andy > > > > > Thanks, > > > > jon > > > > -- > Andy Lutomirski > AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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