linux-kernel - Re: [PATCH 8/8] x86, cleanups: Simplify sync

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Message-ID: <50B8FD9A.3040703@zytor.com>
Date:	Fri, 30 Nov 2012 10:40:26 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Borislav Petkov <bp@...en8.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Mario Gzuk <mariogzuk@...hnikz.de>
Subject: Re: [PATCH 8/8] x86, cleanups: Simplify sync_core() in the case of
 no CPUID

On 11/30/2012 10:10 AM, Borislav Petkov wrote:
> On Fri, Nov 30, 2012 at 10:03:03AM -0800, H. Peter Anvin wrote:
>> Well, the grand total of serializing instructions are:
>>
>> INVD, INVEPT, INVLPG, INVVPID, LGDT, LIDT, LLDT, LTR, MOV to CR, MOV
>> to DR, WBINVD, WRMSR, CPUID, IRET, RSM.
> 
> What about MFENCE with JMP 1f to kill prefetches? Probably too
> expensive. Oh and MFENCE is an SSE2 insn so maybe not supported by 486
> or something later ...

It's not serializing in the strict sense.

	-hpa

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