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

[平松雅巳 / HIRAMATU，MASAMI]

> From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx]
> 
> On 01/09/15 14:38, 平松雅巳 / HIRAMATU，MASAMI wrote:
> >> From: Ingo Molnar [mailto:mingo.kernel.org@xxxxxxxxx] On Behalf Of Ingo Molnar
> >>
> >>
> >> * Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> >>
> >>> Hi
> >>>
> >>> perf tools has a copy of the x86 instruction decoder for decoding
> >>> Intel PT. [...]
> >>
> >> So that's the arch/x86/lib/insn.c instruction length decoder that the kernel uses
> >> for kprobes et al - and the two versions already forked slightly:
> >>
> >> -#include "inat.h"
> >> -#include "insn.h"
> >> +#include <asm/inat.h>
> >> +#include <asm/insn.h>
> >>
> >> 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?
> >>
> >> This will make sure the two versions are fully in sync in the long run as well.
> >>
> >> ( Alternatively we could perhaps also librarize it into tools/lib/, and teach the
> >>   kernel build to pick that one up? )
> >
> > Agreed, what I concern is that someone finds a bug and fixes one of them and
> > another is not fixed.
> >
> > I'll see the forked version and check if it can be merged into the kernel.
> 
> Ever since Linus complained about perf tools including kernel headers, I
> have assumed we should have separate source code.  That email thread was not
> cc'ed to a mailing list but here is a quote:
> 
> Em Sat, Jul 04, 2015 at 08:53:46AM -0700, Linus Torvalds escreveu:
> > So this is more fundamental, and looks like it's just due to perf
> > abusing the kernel headers, and now that rbtree has rcu support
> > ("rbtree: Make lockless searches non-fatal"), it gets tons of headers
> > included that really don't work from user space.
> >
> > There might be other things going on, but the rbtree one seems to be a
> > big one. I think perf needs to get its own rbtree header or something,
> > instead of doing that insane "let's include random core kernel
> > headers" thing.


OK, now I see what happened...
Hmm, so at this point, I'll just port the test to arch/x86/tools/, since the
kernel should have that.

Thanks,



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