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Date: Tue, 01 Jul 2008 17:20:41 -0700 From: "H. Peter Anvin" <hpa@...or.com> To: Jeremy Fitzhardinge <jeremy@...p.org> CC: "Eric W. Biederman" <ebiederm@...ssion.com>, Mike Travis <travis@....com>, Christoph Lameter <clameter@....com>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [crash, bisected] Re: [PATCH 3/4] x86_64: Fold pda into per cpu area Jeremy Fitzhardinge wrote: > > Yes, and there's no reason we couldn't do the same on 64-bit, aside from > the stack-protector's use of %gs:40. There's no code-size cost in large > offsets, since they're always 32-bits anyway (there's no short absolute > addressing mode). > > If we manually generate %gs-relative references to percpu data, then > it's no different to what we do with 32-bit, whether it be a specific > symbol address or using the TLS relocations. > If we think the problem is the zero-basing triggering linker bugs, we should probably just use a small offset, like 64 (put a small dummy section before the .percpu.data section to occupy this section.) I'm going to play with this a bit and see if I come up with something sanish. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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