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Date: Sun, 23 Aug 2015 13:26:52 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>, linux-kernel@vger.kernel.org,
        Brian Gerst <brgerst@gmail.com>, Steven Rostedt <rostedt@goodmis.org>,
        Willy Tarreau <w@1wt.eu>, Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2] x86/entry/32: Remove duplicate initialization of
 tss.ss1
Message-ID: <20150823112652.GA3655@gmail.com>
References: <690f0c629a1085d054e2d1ef3da073cfb3f7db92.1437678821.git.luto@kernel.org>
 <ffbf0c66b0ff54c15459b5e0c5d61334be7fdbec.1437678823.git.luto@kernel.org>
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* Andy Lutomirski <luto@kernel.org> wrote:

> It's statically initialized, so we don't need to dynamically
> initialize it too.
> 
> Reported-by: Brian Gerst <brgerst@gmail.com>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
> 
> Changes since v1: Delete the code :)
> 
> arch/x86/kernel/cpu/common.c | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index e2ed2513a51e..e08eee98a5f8 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1005,14 +1005,6 @@ void enable_sep_cpu(void)
>  	if (IS_ENABLED(CONFIG_X86_32) && !boot_cpu_has(X86_FEATURE_SEP))
>  		goto out;
>  
> -#ifdef CONFIG_X86_32
> -	/*
> -	 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
> -	 * see the big comment in struct x86_hw_tss's definition.
> -	 */
> -	tss->x86_tss.ss1 = __KERNEL_CS;
> -#endif
> -
>  	wrmsrl_safe(MSR_IA32_SYSENTER_CS, __KERNEL_CS);
>  	wrmsrl_safe(MSR_IA32_SYSENTER_ESP,
>  		    (unsigned long)tss +

So this code changed substantially in tip:x86/asm - do we still need this patch?

Thanks,

	Ingo