From: Segher Boessenkool <segher@kernel.crashing.org>
To: Tulio Magno Quites Machado Filho <tuliom@ascii.art.br>
Cc: Florian Weimer <fweimer@redhat.com>,
gcc@gcc.gnu.org, libc-alpha@sourceware.org,
Nicholas Piggin <npiggin@gmail.com>,
Paul E Murphy <murphyp@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] powerpc: add documentation for HWCAPs
Date: Fri, 15 Jul 2022 14:59:51 -0500 [thread overview]
Message-ID: <20220715195951.GA25951@gate.crashing.org> (raw)
In-Reply-To: <877d4euskv.fsf@linux.ibm.com>
On Fri, Jul 15, 2022 at 03:41:20PM -0300, Tulio Magno Quites Machado Filho wrote:
> Nicholas Piggin <npiggin@gmail.com> writes:
>
> > +PPC_FEATURE_ARCH_2_05
> > + The processor supports the v2.05 userlevel architecture. Processors
> > + supporting later architectures also set this feature.
>
> I don't think this bit is enabled when processors support later architectures.
> In my tests, this behavior started only with v2.06, i.e. processors that
> support v2.07 enable bit v2.06, but do not enable bit v2.05.
That is a usability problem. Can it be fixed, or will that create its
own compatibility problems? In practice I mean. If it is, the C
libraries could fix it up, for new programs, and then after a while the
kernel can do the sane thing?
How big is the problem, anyway? Is it only 2.05, or also 2.04, 2.03?
Segher
next prev parent reply other threads:[~2022-07-15 20:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-15 1:26 [PATCH v2] powerpc: add documentation for HWCAPs Nicholas Piggin
2022-07-15 14:57 ` Segher Boessenkool
2022-07-15 18:41 ` Tulio Magno Quites Machado Filho
2022-07-15 19:59 ` Segher Boessenkool [this message]
2022-07-15 20:17 ` Tulio Magno Quites Machado Filho
2022-07-20 9:28 ` Nicholas Piggin
2022-07-29 13:02 ` Michael Ellerman
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