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From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
	One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Brian Gerst <brgerst@gmail.com>,
	Matthew Whitehead <tedheadster@gmail.com>
Subject: Re: [PATCH v2 3/6] x86/cpu: Re-apply forced caps every time cpu caps are re-read
Date: Thu, 19 Jan 2017 12:23:01 +0100
Message-ID: <20170119112301.fop6boxbpyk3tf4a@pd.tnic> (raw)
In-Reply-To: <c817eb373d2c67c2c81413a70fc9b845fa34a37e.1484705016.git.luto@kernel.org>

On Wed, Jan 18, 2017 at 11:15:39AM -0800, Andy Lutomirski wrote:
> Calling get_cpu_cap() will reset a bunch of CPU features.  This will
> cause the system to lose track of force-set and force-cleared
> featueres in the words that are reset until the end of CPU

features

> initialization.  This can cause X86_FEATURE_FPU, for example, to
> change back and forth during boot and potentially confuse CPU setup.
> 
> To minimize the chance of confusion, re-apply forced caps every time
> get_cpu_cap() is called.
> 
> Signed-off-by: Andy Lutomirski <luto@kernel.org>

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-18 19:15 [PATCH v2 0/6] CPUID and FPU fixes Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 3/6] x86/cpu: Re-apply forced caps every time cpu caps are re-read Andy Lutomirski
2017-01-19 11:23   ` Borislav Petkov [this message]
2017-01-25 11:41   ` [tip:x86/fpu] x86/cpu: Re-apply forced caps every time CPU " tip-bot for Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 5/6] x86/fpu: Fix CPUID-less FPU detection Andy Lutomirski
2017-01-19 11:23   ` Borislav Petkov
2017-01-25 11:42   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2017-01-18 19:15 [PATCH v2 1/6] x86/cpu: Add X86_FEATURE_CPUID Andy Lutomirski
2017-01-25 11:40 ` [tip:x86/fpu] " tip-bot for Borislav Petkov
2017-01-18 19:15 [PATCH v2 2/6] x86/cpu: Factor out application of forced cpu caps Andy Lutomirski
2017-01-25 11:40 ` [tip:x86/fpu] x86/cpu: Factor out application of forced CPU caps tip-bot for Andy Lutomirski
2017-01-18 19:15 [PATCH v2 4/6] x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected" message Andy Lutomirski
2017-01-25 11:42 ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2017-01-18 19:15 [PATCH v2 6/6] x86/fpu: Fix the "Giving up, no FPU found" test Andy Lutomirski
2017-01-25 11:43 ` [tip:x86/fpu] " tip-bot for Andy Lutomirski

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