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Date: Fri, 24 Nov 2017 15:19:00 +0100
From: Borislav Petkov <bp@alien8.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 11/43] x86/entry/64: Separate cpu_current_top_of_stack
 from TSS.sp0
Message-ID: <20171124141900.lrxeed3qepxtiyzp@pd.tnic>
References: <20171124091448.7649-1-mingo@kernel.org>
 <20171124091448.7649-12-mingo@kernel.org>
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On Fri, Nov 24, 2017 at 10:14:16AM +0100, Ingo Molnar wrote:
> From: Andy Lutomirski <luto@kernel.org>
> 
> On 64-bit kernels, we used to assume that TSS.sp0 was the current
> top of stack.  With the addition of an entry trampoline, this will
> no longer be the case.  Store the current top of stack in TSS.sp1,
> which is otherwise unused but shares the same cacheline.
> 
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Borislav Petkov <bpetkov@suse.de>
> Cc: Brian Gerst <brgerst@gmail.com>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Denys Vlasenko <dvlasenk@redhat.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Link: http://lkml.kernel.org/r/f56634c746a2926eb7bae61e7b80ed51a1940769.1511497875.git.luto@kernel.org
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> ---
>  arch/x86/include/asm/processor.h   | 18 +++++++++++++-----
>  arch/x86/include/asm/thread_info.h |  2 +-
>  arch/x86/kernel/asm-offsets_64.c   |  1 +
>  arch/x86/kernel/process.c          | 10 ++++++++++
>  arch/x86/kernel/process_64.c       |  1 +
>  5 files changed, 26 insertions(+), 6 deletions(-)

Reviewed-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

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