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Re: valgrind support for glibc/kernel arm64 HWCAPS
- From: Mark Wielaard <mark at klomp dot org>
- To: Siddhesh Poyarekar <siddhesh at gotplt dot org>
- Cc: Florian Weimer <fweimer at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>, valgrind-developers at lists dot sourceforge dot net
- Date: Wed, 05 Jul 2017 21:48:31 +0200
- Subject: Re: valgrind support for glibc/kernel arm64 HWCAPS
- Authentication-results: sourceware.org; auth=none
- References: <4cc2a089-aa95-61e3-19ff-437efda1b420@redhat.com> <1498215666.3709.126.camel@fedoraproject.org> <292f23e0-ce84-54d3-e2b6-416f7acae81d@gotplt.org> <21e8ef62-e393-6c0e-51ca-ac4b03f97ded@redhat.com> <f47d3e6c-27d7-079e-b9a2-5378c62b31bb@gotplt.org> <1498218016.3709.140.camel@fedoraproject.org> <5b42bde5-0a8d-82b4-ef39-64634f059390@gotplt.org> <1499269376.14595.9.camel@klomp.org> <68d1e552-b25a-ca51-33ed-96a8f1b35f42@gotplt.org>
On Thu, 2017-07-06 at 00:26 +0530, Siddhesh Poyarekar wrote:
> On Wednesday 05 July 2017 09:12 PM, Mark Wielaard wrote:
> > I am not sure I understand this part.
> > What are micro-architecture specific routines?
>
> These are routines written specifically for vendor CPUs, such as the
> thunderx version of memcpy and memmove. The HWCAP_CPUID allows for such
> routines to be launched on the correct hardware, but when run under
> valgrind, those routines will not get called and any potential bugs in
> those routines may get masked.
aha. We probably already intercept such implementations of memcpy and
memmove with our own versions anyway. See the shared/vg_replace_strmem.c
source in valgrind for some of the reasons for intercepting these hyper
optimized string/memory functions.
Cheers,
Mark