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From: Florian Weimer <fweimer@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: V9 [PATCH] x86: Support usable check for all CPU features
Date: Wed, 08 Jul 2020 17:49:25 +0200	[thread overview]
Message-ID: <87r1tmovlm.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <CAMe9rOocqG65SkJ2HRNtHJvSAQfyRoyykax9vgwHgLLTt4c_bg@mail.gmail.com> (H. J. Lu's message of "Tue, 7 Jul 2020 04:46:08 -0700")

* H. J. Lu:

> +  /* Before COMMON_CPUID_INDEX_80000001, clear the unknown usable bits
> +     and the always zero bits.  */
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_1_ECX_16);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_1_ECX_31);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_10);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_20);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_30);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_EBX_6);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_EBX_22);

INDEX_7_EBX_13 is missing, I think.

> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_13);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_15);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_16);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_23);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_24);
> +  CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_26);

INDEX_7_ECX_17 and four more are missing.

We do not mask unknown flags in the EAX and EDX registers, those are
copied unconditionally.  Is this a problem?

Thanks,
Florian


  reply	other threads:[~2020-07-08 15:49 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30  4:35 V7: [PATCH 0/2] x86: Install <sys/platform/x86.h> H.J. Lu
2020-06-30  4:35 ` V7: [PATCH 1/2] x86: Support usable check for all CPU features H.J. Lu
2020-07-04 17:17   ` H.J. Lu
2020-07-06 10:45     ` Florian Weimer
2020-07-06 14:28       ` V8: [PATCH] " H.J. Lu
2020-07-07 11:18         ` Florian Weimer
2020-07-07 11:46           ` V9 " H.J. Lu
2020-07-08 15:49             ` Florian Weimer [this message]
2020-07-08 16:32               ` V10 " H.J. Lu
2020-07-12 12:36                 ` H.J. Lu
2020-07-13 11:19                 ` Florian Weimer
2020-07-13 12:40                   ` H.J. Lu
2021-03-08 14:26                     ` Andreas Schwab
2021-03-08 14:29                       ` Florian Weimer
2020-06-30  4:35 ` V7: [PATCH 2/2] x86: Install <sys/platform/x86.h> [BZ #26124] H.J. Lu
2020-07-15 14:55   ` PING: " H.J. Lu
2020-07-15 14:58     ` H.J. Lu
2020-07-16 20:15   ` Carlos O'Donell

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