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Re: Spectre V1 diagnostic / mitigation
On Wed, 19 Dec 2018, Florian Weimer wrote:
> * Richard Biener:
> > The cost is probably target dependent - on x86 it's simply a $fs based
> > load/store.
> Do you need to reserve something in the TCB for this?
No idea. But I figured using TLS with the patch only works when
optimizing and not with -O0. Huh. Anyway, it should be equivalent
to what presence of
__thread void *_SV1MASK = (void *)-1l;
requires (plus I make that symbol GNU_UNIQUE). I see this
allocates -1 in the .tdata section marked TLS.
Richard Biener <firstname.lastname@example.org>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)