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Date: Wed, 19 Nov 2008 13:06:14 -0800 From: Jeremy Fitzhardinge <jeremy@...p.org> To: Eric Lacombe <goretux@...il.com> CC: Arjan van de Ven <arjan@...radead.org>, Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org Subject: Re: [x86] do_arch_prctl - bug? Eric Lacombe wrote: > Ok, thanks, so I suppose now that only doing : > asm volatile("movl %0,%%gs" :: "r" (0)); > could corrupt the address of the PDA that resides actually in the MSR_GS_BASE. > And that's why load_gs_index is used as it contains "swapgs" before and after > the "mov to gs". > > Is that correct? > Yes, loading a selector into a segment register will load the lower 32 bits of the base from the ldt/gdt into the msr and zero the rest. J -- 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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