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Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support

From Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups linux.kernel
Subject Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support
Date 2016-12-08 21:10 +0100
Message-ID <sMdaV-254-17@gated-at.bofh.it> (permalink)
References <sM9K2-8la-5@gated-at.bofh.it> <sM9K2-8la-3@gated-at.bofh.it> <sMdaV-254-15@gated-at.bofh.it>
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On Thu, Dec 8, 2016 at 12:05 PM, Borislav Petkov <bp@alien8.de> wrote:
>
> The cpuid() in cpuflags.c doesn't zero ecx which, if we have to be
> pedantic, it should do. It calls CPUID now with the ptr value of its 4th
> on 64-bit and 3rd arg on 32-bit, respectively, IINM.

In fact, just do a single cpuid_count(), and then implement the
traditional cpuid() as just

   #define cpuid(x, a,b,c,d) cpuid_count(x, 0, a, b, c, d)

or something.

Especially since that's some of the ugliest inline asm ever due to the
nasty BX handling.

          Linus

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Thread

[RFC, PATCHv1 15/28] x86: detect 5-level paging support "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support Borislav Petkov <bp@alien8.de> - 2016-12-08 21:10 +0100
    Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support Linus Torvalds <torvalds@linux-foundation.org> - 2016-12-08 21:10 +0100
      Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support Borislav Petkov <bp@alien8.de> - 2016-12-08 21:30 +0100
    Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-09 16:40 +0100
      Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support Borislav Petkov <bp@alien8.de> - 2016-12-09 17:40 +0100

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