On Tue, Sep 30, 2003 at 08:04:42PM +0200, Maciej W. Rozycki wrote: > > > What would be the downside to enabling 64 bit operations in user space > > > on a 32 bit kernel (setting the PX bit in the status register?). The > > > particular issue is that I want to access 64 bit-memory mapped registers, > > > and I really need to do it as an atomic operation. I tried borrowing > > > sibyte/64bit.h from the kernel, but I get an illegal instruction on the > > > double ops. > > > > Common design bug in hardware, imho ... > > Well, ioremap() can be used to get at these areas (as well as any > others), whether we call it a bug or not. What I called a bug is the necessity to access hardware registers with 64-bit loads and stores in some systems as opposed to of 32-bit instructions - that simply doesn't work from 32-bit universes. To clarify, it was my understanding of Steve's problem he needs 64-bit loads and stores, not something in the 64-bit physical address space. The later problem obviously would get a different answer. Ralf
