Re: [PATCH 0/4] x86/insn: perf tools: Add a few new x86 instructions

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Sep 01, 2015 at 03:59:16PM +0200, Jiri Olsa escreveu:
> On Tue, Sep 01, 2015 at 03:16:52PM +0300, Adrian Hunter wrote:
> > On 01/09/15 11:54, Ingo Molnar wrote:
> > > it would be nice to add a diff check to the perf build, and (non-fatally) warn 
> > > during the build if the two versions depart from each other?

> > I had a go and came up with this.  Arnaldo, Jiri any comments?

> > diff --git a/tools/perf/util/intel-pt-decoder/Build b/tools/perf/util/intel-pt-decoder/Build
> > +	diff -B -I'^#include' util/intel-pt-decoder/insn.h ../../arch/x86/include/asm/insn.h >/dev/null && \
> > +	diff -B -I'^#include' util/intel-pt-decoder/inat.h ../../arch/x86/include/asm/inat.h >/dev/null && \
> > +	diff -B -I'^#include' util/intel-pt-decoder/inat_types.h ../../arch/x86/include/asm/inat_types.h >/dev/null) \
> > +	|| echo "Warning: Intel PT: x86 instruction decoder differs from kernel" >&2 )
> > +	$(call rule_mkdir)
> > +	$(call if_changed_dep,cc_o_c)
 
> seems ok, but it might be nicer to have make function for that
> so we could use it on other places like rbtree.h

That will pose some more hurdles, as there are things like
EXPORT_SYMBOL() and RCU stuff that are ok in the kernel sources, but not
in the tools/ copy...

I.e. fully sharing will put a new burden for kernel developers working
on the to-be-shared code, which is something that is not desired.

I was ok with, hey, tools/ broke because you're sharing code with the
kernel, as probably a tools/ developer would notice that and fix things,
but Linus advised against that.

- Arnaldo