Re: [PATCH 1/7] x86/vm86: Clean up saved_fs/gs

From	Brian Gerst <brgerst@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/7] x86/vm86: Clean up saved_fs/gs
Date	2015-07-16 18:00 +0200
Message-ID	<pMTJN-2N2-27@gated-at.bofh.it> (permalink)
References	<pMPPP-5zU-5@gated-at.bofh.it> <pMPPP-5zU-3@gated-at.bofh.it> <pMTA6-2Br-19@gated-at.bofh.it>
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On Thu, Jul 16, 2015 at 11:45 AM, Andy Lutomirski <luto@amacapital.net> wrote:
> On Thu, Jul 16, 2015 at 4:46 AM, Brian Gerst <brgerst@gmail.com> wrote:
>> There is no need to save FS and non-lazy GS outside the 32-bit regs.  Lazy GS
>> still needs to be saved because it wasn't saved on syscall entry.
>
> I think I'm missing something.  Why can't you just lazy_save_gs into regs32->gs?
>
> --Andy

That is probably a better idea.  The gs field exists in pt_regs but is
unused in lazy mode.  Could also change switch_to() to store GS in
pt_regs instead of thread.gs, which would simplify ptrace a bit.

--
Brian Gerst
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[PATCH 1/7] x86/vm86: Clean up saved_fs/gs Brian Gerst <brgerst@gmail.com> - 2015-07-16 13:50 +0200
  Re: [PATCH 1/7] x86/vm86: Clean up saved_fs/gs Andy Lutomirski <luto@amacapital.net> - 2015-07-16 17:50 +0200
    Re: [PATCH 1/7] x86/vm86: Clean up saved_fs/gs Brian Gerst <brgerst@gmail.com> - 2015-07-16 18:00 +0200

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