From: "Gabriel F. T. Gomes" <gabriel@inconstante.eti.br>
To: Tulio Magno Quites Machado Filho <tuliom@ascii.art.br>
Cc: Rogerio Alves <rcardoso@linux.ibm.com>,
Florian Weimer <fweimer@redhat.com>, <libc-alpha@sourceware.org>
Subject: Re: [PATCH] power: Fix VSCR position on ucontext
Date: Mon, 10 Dec 2018 18:12:00 -0000 [thread overview]
Message-ID: <20181210160819.276c5822@tereshkova> (raw)
In-Reply-To: <87wooh8gfg.fsf@linux.ibm.com>
On Mon, 10 Dec 2018, Tulio Magno Quites Machado Filho wrote:
>"Gabriel F. T. Gomes" <gabriel@inconstante.eti.br> writes:
>
>> [ text/plain ]
>> On Fri, 07 Dec 2018, Rogerio Alves wrote:
>>
>>>+/* This test is supported only on POWER 5 or higher. */
>>>+#define PPC_CPU_SUPPORTED (PPC_FEATURE_POWER5 | PPC_FEATURE_POWER5_PLUS | \
>>>+ PPC_FEATURE_ARCH_2_05 | PPC_FEATURE_ARCH_2_06 | \
>>>+ PPC_FEATURE2_ARCH_2_07)
>>
>> Is this actually needed? Glibc has code to fill all the bits for older
>> architectures in sysdeps/powerpc/hwcapinfo.c [1]. So, as far as I can
>> see, you only need to test for AT_HWCAP & PPC_FEATURE_POWER5.
>
>Yes, it's indeed required to check all these bits when using getauxval().
>
>> [1] https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/powerpc/hwcapinfo.c;h=a09b18309324423d0cdf04e88367899a4396bab7;hb=HEAD#l47
>
>This code is preparing the data for __builtin_cpu_supports().
>So, when using this built-in, it wouldn't be necessary to check for all those
>AT_HWCAP bits.
Oh, I see. Thanks for the explanation. :)
next prev parent reply other threads:[~2018-12-10 18:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 16:14 Rogerio Alves
2018-11-14 18:00 ` Florian Weimer
2018-11-16 13:18 ` Gabriel F. T. Gomes
2018-12-07 18:28 ` Rogerio Alves
2018-12-07 19:23 ` Gabriel F. T. Gomes
2018-12-10 17:18 ` Tulio Magno Quites Machado Filho
2018-12-10 18:12 ` Gabriel F. T. Gomes [this message]
2018-12-10 18:08 ` Gabriel F. T. Gomes
2018-12-10 18:25 ` Rogerio Alves
2018-12-10 21:20 ` Tulio Magno Quites Machado Filho
2018-12-19 19:30 ` Rogerio Alves
2019-01-10 19:52 ` Tulio Magno Quites Machado Filho
2019-01-11 12:01 ` Szabolcs Nagy
2019-01-11 12:15 ` Tulio Magno Quites Machado Filho
2019-01-11 19:52 ` Tulio Magno Quites Machado Filho
2019-01-11 23:49 ` Joseph Myers
2019-01-12 0:50 ` Tulio Magno Quites Machado Filho
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