Re: [RFC] hwbkpt: Hardware breakpoints (was Kwatch)

From: Roland McGrath
Date: Tue Mar 06 2007 - 22:49:51 EST


> > Yeah, I guess that's right. It should still return NOTIFY_STOP when
> > args->err has no other bits set, so notifiers aren't called with zero.
>
> In practice that might not work. On my machine, at least, reads of DR6
> return ones in all the reserved bit positions.

Does that mean asm("mov %1,%%dr6; mov %%dr6,%0" : "=r" (mask) : "r" (0));
puts in mask the set of reserved bits? We could collect that value at CPU
startup and mask it off args->err, then OR it back into vdr6.


Thanks,
Roland
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