Re: Memory corruption due to word sharing

From: Peter Bergner
Date: Wed Feb 01 2012 - 14:04:35 EST


On Wed, 2012-02-01 at 13:09 -0500, David Miller wrote:
> From: Michael Matz <matz@xxxxxxx>
> Date: Wed, 1 Feb 2012 18:41:05 +0100 (CET)
>
> > One problem is that it's not a new problem, GCC emitted similar code since
> > about forever, and still they turned up only now (well, probably because
> > ia64 is dead, but sparc64 should have similar problems).
>
> Indeed, on sparc64 it does do the silly 64-bit access too:
>
> wrong:
> ldx [%o0+8], %g2
> sethi %hi(2147483648), %g1
> or %g2, %g1, %g1
> jmp %o7+8
> stx %g1, [%o0+8]

Ditto for powerpc64-linux:

ld 9,8(3)
li 10,1
rldimi 9,10,31,32
std 9,8(3)
blr


Peter



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