Hi,
On Wed, 18 Oct 2017, Segher Boessenkool wrote:
> Certainly. And to work around the bug, it should work to mention some
> hard register as asm input. Ideally something that is live anyway;
> perhaps the stack pointer :-) Like so:
>
> __asm volatile ("mrs %0,PRIMASK" : "=r" (status) :: "sp");
>
> (I tested this, it does work around the bug).
>
> Or hey, why not the program counter, that should make it even clearer
> something is funny here:
>
> __asm volatile ("mrs %0,PRIMASK" : "=r" (status) :: "pc");
>
> (also tested, works fine).
Both of these are not asm inputs but clobbers, though :) And clobbering
"pc" could have funny effects if any of our allocators ever would produce
save/restore code around such asms for such clobbers.
Ciao,
Michael.
