Hi guys,
On Mon, Mar 04, 2013 at 02:45:33AM +0000, Rob Herring wrote:
> On 02/20/2013 05:48 AM, Ian Campbell wrote:
> > On ARM we want these to be the same size on 32- and 64-bit.
> >
> > This is an ABI change on ARM. X86 does not change.
> >
> > Signed-off-by: Ian Campbell <[email protected]>
> > Cc: Jan Beulich <[email protected]>
> > Cc: Keir (Xen.org) <[email protected]>
> > Cc: Tim Deegan <[email protected]>
> > Cc: Stefano Stabellini <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: Konrad Rzeszutek Wilk <[email protected]>
[...]
> I'm seeing some some build failures on randconfig builds with this change:
>
> /tmp/ccJaIZOW.s: Assembler messages:
> /tmp/ccJaIZOW.s:831: Error: even register required -- `ldrexd r5,r6,[r4]'
>
> This is with ubuntu 12.04 cross compiler (gcc version 4.6.3
> (Ubuntu/Linaro 4.6.3-1ubuntu5)).
>
> This register restriction is on ARM, but not Thumb builds. Comparing
> this to atomic64_cmpxchg, I don't see how to fix this. Perhaps Will or
> Nico have thoughts.
[...]
> > + asm volatile("@ xchg_xen_ulong\n"
> > + "1: ldrexd %0, %H0, [%3]\n"
> > + " strexd %1, %2, %H2, [%3]\n"
> > + " teq %1, #0\n"
> > + " bne 1b"
> > + : "=&r" (oldval), "=&r" (tmp)
> > + : "r" (val), "r" (ptr)
> > + : "memory", "cc");
I also can't immediately see why GCC would allocate oldval to an odd base
register. Can you share your .config please?
Will
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