Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

[David S. Miller]

On Tue, 25 May 2004 09:19:52 -0700 (PDT)
Linus Torvalds <torvalds@xxxxxxxx> wrote:

> On Tue, 25 May 2004, Keith M Wesolowski wrote:
> > 
> > Some sparc32 CPUs are also vulnerable to this race; in fact the
> > supersparc manual describes it specifically and even outlines the
> > compare-exchange loop using our rotten swap instruction.  In our case,
> > the race is with a hardware walker.
> 
> Yes, but the sparc32 page tables are not the same as the linux kernel page 
> tables, so in your case it's a different path and a different page table. 
> Only the shared case really matters (ie things that do hw/microcode walk 
> of a page table _tree_ not a hash).

Not true on 32-bit Sparc sun4m systems, it's exactly like i386 except
the hardware is stupid and we only have an atomic swap instruction.
:-)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/