On Fri, May 25, 2001 at 05:27:46PM -0300, Ralf Baechle wrote:
> On Thu, May 24, 2001 at 03:42:56PM +0200, Maciej W. Rozycki wrote:
> > > The ll/sc constructs in the kernel use ".set noat" to inhibit use of $at,
> > > and proceed to use it themselves. This is fine, except for one problem:
> > > the
> > > constraints on memory operands are "o" and "=o", which means offsettable
> > > memory references. If I'm not mistaken, the assembler will (always?)
> > > turn these into uses of $at if the offset is not 0 - at least, it
> > > certainly
> > > seems to do that here (gcc 2.95.3, binutils 18.104.22.168.2). Just being
> > > honest
> > > with the compiler and asking for a real memory reference does the trick.
> > Both "m" and "o" seem to be incorrect here as both are the same for MIPS;
> > "R" seems to be appropriate, OTOH. Still gcc 2.95.3 doesn't handle "R"
> > fine for all cases, but it works most of the time and emits a warning
> > otherwise. I can't comment on 3.0.
> I admit the construction is somewhat fragile and will take any patches to
> cleanup this.
How about the attached, then? If the p[0x100000] case is of sufficient
concern, we can work around that too, but this catches all current
Daniel Jacobowitz Debian GNU/Linux Developer
Monta Vista Software Debian Security Team
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