| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.9 004/133] drm/i915/gem: Prevent using pgprot_writecombine() if PAT is not supported | Date | Mon, 9 Nov 2020 13:54:26 +0100 |
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From: Chris Wilson <chris@chris-wilson.co.uk>
commit ba2ebf605d5f32a9be0f7b05d3174bbc501b83fe upstream.
Let's not try and use PAT attributes for I915_MAP_WC if the CPU doesn't support PAT.
Fixes: 6056e50033d9 ("drm/i915/gem: Support discontiguous lmem object maps") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Cc: <stable@vger.kernel.org> # v5.6+ Link: https://patchwork.freedesktop.org/patch/msgid/20200915091417.4086-2-chris@chris-wilson.co.uk (cherry picked from commit 121ba69ffddc60df11da56f6d5b29bdb45c8eb80) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/gpu/drm/i915/gem/i915_gem_pages.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c @@ -254,6 +254,10 @@ static void *i915_gem_object_map(struct if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC) return NULL; + if (GEM_WARN_ON(type == I915_MAP_WC && + !static_cpu_has(X86_FEATURE_PAT))) + return NULL; + /* A single page can always be kmapped */ if (n_pte == 1 && type == I915_MAP_WB) { struct page *page = sg_page(sgt->sgl);
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