From: Arnd Bergmann > Sent: 30 July 2021 17:59 ... > I am not aware of any driver that requires unaligned access on __iomem > pointers, and since it definitely doesn't work on most architectures, ... Unaligned accesses into PCIe space can generate a TLP that requests only some bytes of the first and last 32bit words be transferred. The target is expected to honour such requests. On the x86 systems where I've looked at a TLP trace misaligned accesses are even atomic provided the target doesn't let a local request interleave. OTOH drivers are unlikely to make such requests. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
