Re: [PATCH 01/17] x86, fpu: wrap get_xsave_addr() to make it safer

Borislav Petkov
2015-04-25T09:31:35Z

On Wed, Apr 22, 2015 at 11:27:31AM -0700, Dave Hansen wrote:
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Changes from "v19":
> * remove 'tsk' argument to get_xsave_addr() since the code
> can only realistically work on 'current', and fix up the
> comment a bit to match.
>
> Changes from "v17":
> * fix s/xstate/xsave_field/ in the function comment
> * remove EXPORT_SYMBOL_GPL()
>
> ---
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> The MPX code appears to be saving off the FPU in an unsafe
> way. It does not disable preemption or ensure that the
> FPU state has been allocated.
>
> This patch introduces a new helper which will do both of
> those things internally.
>
> Note that this requires a patch from Oleg in order to work
> properly. It is currently in tip/x86/fpu.
>
> > commit f893959b0898bd876673adbeb6798bdf25c034d7
> > Author: Oleg Nesterov <oleg@redhat.com>
> > Date: Fri Mar 13 18:30:30 2015 +0100
> >
> > x86/fpu: Don't abuse drop_init_fpu() in flush_thread()
>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: bp@alien8.de
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Suresh Siddha <sbsiddha@gmail.com>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: the arch/x86 maintainers <x86@kernel.org>
> ---
>
> b/arch/x86/include/asm/xsave.h | 1 +
> b/arch/x86/kernel/xsave.c | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 33 insertions(+)

Applied, thanks.

--
Regards/Gruss,
Boris.

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