drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1 page
authorMichel Thierry <michel.thierry@intel.com>
Mon, 11 Jan 2016 11:39:27 +0000 (11:39 +0000)
committerJani Nikula <jani.nikula@intel.com>
Wed, 13 Jan 2016 08:50:55 +0000 (10:50 +0200)
commit48ea1e32c39db94c59b63580b965222c7782112f
tree9aab3e55f1b9c98c73a7a983edd7ccf2acaa2946
parentde0513365cff619335a59417dea1d1ca665c2cfd
drm/i915/gen9: Set PIN_ZONE_4G end to 4GB - 1 page

Kernel and userspace are able to handle 4GB (1<<32) address space range,
but "A32 Stateless Model" is not. According to documentation, A32 accesses
are based on General State Base Address and bound checking is in place.
Because size field (instruction State Base Address) limitation, it is not
possible to address full 4GB memory region.

A32 Stateless Model is used by some libraries and without this patch, the
last page of 4GB address space is not accessible in 32bit processes.

Reported-by: Artur Harasimiuk <artur.harasimiuk@intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452512367-23614-1-git-send-email-michel.thierry@intel.com
Cc: drm-intel-fixes@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 1892faa9ec5d51b07d646cbd5597cd30e049aa51)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drivers/gpu/drm/i915/i915_gem.c