On Mon, Jun 22, 2015 at 12:09 PM, Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> wrote: > [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@xxxxxxx> wrote: >> > On Sat, 20 Jun 2015 21:10:28 -0400 >> > Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> 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. Oh, right. Do we have something like hostprogs that builds for the target instead of the host? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-next" in
