[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. Paul. -- > > --Andy > > > > > Thanks, > > > > jon > > > > -- > Andy Lutomirski > AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in
