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Re: [RFC PATCH -v2.1] x86: Kill notsc

From Borislav Petkov <bp@alien8.de>
Newsgroups linux.kernel
Subject Re: [RFC PATCH -v2.1] x86: Kill notsc
Date 2015-11-17 10:00 +0100
Message-ID <qvKhk-2Hb-7@gated-at.bofh.it> (permalink)
References (4 earlier) <qr3ui-7C4-21@gated-at.bofh.it> <qr3ui-7C4-29@gated-at.bofh.it> <qvx0J-2t2-13@gated-at.bofh.it> <qvzvA-4cE-37@gated-at.bofh.it> <qvGGK-zE-3@gated-at.bofh.it>
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On Mon, Nov 16, 2015 at 09:02:15PM -0800, H. Peter Anvin wrote:
> On 11/16/15 13:25, Thomas Gleixner wrote:
> > On Mon, 16 Nov 2015, Borislav Petkov wrote:
> >> -/*
> >> - * disable flag for tsc. Takes effect by clearing the TSC cpu flag
> >> - * in cpu/common.c
> >> - */
> >> -int __init notsc_setup(char *str)
> >> +/* Disable the TSC feature flag to avoid further TSC use. */
> >> +int __init notsc_setup(void)
> >>  {
> >> +#ifndef CONFIG_X86_TSC
> >>  	setup_clear_cpu_cap(X86_FEATURE_TSC);
> > 
> > This is silly, really.
> > 
> > If CONFIG_X86_TSC is disabled then we should just not compile tsc.c at
> > all and map cpu_has_tsc and stuff depending on it to false.
> > 
> 
> CONFIG_X86_TSC means TSC is obligatory, not that it is supported.

Hmm, I'd still need to untangle tsc.c though for people who want to
disable it for whatever reason.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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Thread

[RFC PATCH -v2.1] x86: Kill notsc Borislav Petkov <bp@alien8.de> - 2015-11-16 19:50 +0100
  Re: [RFC PATCH -v2.1] x86: Kill notsc Thomas Gleixner <tglx@linutronix.de> - 2015-11-16 22:30 +0100
    Re: [RFC PATCH -v2.1] x86: Kill notsc "H. Peter Anvin" <hpa@zytor.com> - 2015-11-17 06:10 +0100
      Re: [RFC PATCH -v2.1] x86: Kill notsc Borislav Petkov <bp@alien8.de> - 2015-11-17 10:00 +0100
        Re: [RFC PATCH -v2.1] x86: Kill notsc Thomas Gleixner <tglx@linutronix.de> - 2015-11-17 10:20 +0100
          Re: [RFC PATCH -v2.1] x86: Kill notsc Borislav Petkov <bp@alien8.de> - 2015-11-17 10:40 +0100
            Re: [RFC PATCH -v2.1] x86: Kill notsc Thomas Gleixner <tglx@linutronix.de> - 2015-11-17 11:10 +0100
              Re: [RFC PATCH -v2.1] x86: Kill notsc Borislav Petkov <bp@alien8.de> - 2015-11-17 12:20 +0100

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