[PATCH .36-rc8] arm: mm: allow, but warn, when issuing ioremap() on RAM

Felipe Contreras felipe.contreras at gmail.com
Fri Oct 15 10:25:07 EDT 2010

On Fri, Oct 15, 2010 at 5:15 PM, Felipe Contreras
<felipe.contreras at gmail.com> wrote:
> From: Catalin Marinas <catalin.marinas at arm.com>
> Drivers have been relying on this behavior, but done so wrongly.
> However, rather than breaking drivers from .35 to .36, we should warn on
> .36 and only break on .37. This way we give a chance for contributors to
> fix the issues.
> According to ARM, the behavior of having multiple mappings is
> unspecified from ARMv6+. This causes real issues specially on modern
> hardware, and specially with speculative prefetching. So drivers need to
> be fixed.
> Also, since current hardware has palliative meassures to deal with
> multiple mappings with the same memory type but diferent cacheability
> attributes, ensure that such restriction is taking place.

Ah, disregard this, a similar one is on .36-rc8 already (06c1088), I
wasn't CC'ed.

Felipe Contreras

More information about the linux-arm-kernel mailing list