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From: Andy Lutomirski <luto@amacapital.net>
To: Jan Beulich <JBeulich@suse.com>,
	mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] x86-64: allow using RIP-relative addressing for per-CPU data
Date: Tue, 04 Nov 2014 11:33:13 -0800	[thread overview]
Message-ID: <545929F9.7010301@amacapital.net> (raw)
In-Reply-To: <5458A12C0200007800044A97@mail.emea.novell.com>

On 11/04/2014 12:49 AM, Jan Beulich wrote:
> Observing that per-CPU data (in the SMP case) is reachable by
> exploiting 64-bit address wraparound, these two patches
> arrange for using the one byte shorter RIP-relative addressing
> forms for the majority of per-CPU accesses.
> 
> 1: handle PC-relative relocations on per-CPU data
> 2: use RIP-relative addressing for most per-CPU accesses
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 

I'm lost here.  Can you give an example of a physical and virtual
address of an instruction, the address within the gs segment, and why
the relocations are backwards?

--Andy

  reply	other threads:[~2014-11-04 19:33 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-04  8:49 [PATCH 0/2] x86-64: allow using RIP-relative addressing for per-CPU data Jan Beulich
2014-11-04 19:33 ` Andy Lutomirski [this message]
2014-11-05 17:09   ` Jan Beulich
2014-11-05 17:15     ` Andy Lutomirski

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