drm/i915: Prevent writing into a read-only object via a GGTT mmap

[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / i915 / i915_gem_gtt.c

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 430b4bf70469afe7e9ed138feb2e939bf2835bc2..8151196d323bbdf89f302d5f9ed11cd7cd33d304 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -205,7 +205,7 @@ static int ppgtt_bind_vma(struct i915_vma *vma,
 
        /* Applicable to VLV, and gen8+ */
        pte_flags = 0;
-       if (vma->obj->gt_ro)
+       if (i915_gem_object_is_readonly(vma->obj))
                pte_flags |= PTE_READ_ONLY;
 
        vma->vm->insert_entries(vma->vm, vma, cache_level, pte_flags);
@@ -2366,8 +2366,10 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
        const gen8_pte_t pte_encode = gen8_pte_encode(0, level, 0);
        dma_addr_t addr;
 
-       /* The GTT does not support read-only mappings */
-       GEM_BUG_ON(flags & PTE_READ_ONLY);
+       /*
+        * Note that we ignore PTE_READ_ONLY here. The caller must be careful
+        * not to allow the user to override access to a read only page.
+        */
 
        gtt_entries = (gen8_pte_t __iomem *)ggtt->gsm;
        gtt_entries += vma->node.start >> PAGE_SHIFT;
@@ -2609,7 +2611,7 @@ static int ggtt_bind_vma(struct i915_vma *vma,
 
        /* Applicable to VLV (gen8+ do not support RO in the GGTT) */
        pte_flags = 0;
-       if (obj->gt_ro)
+       if (i915_gem_object_is_readonly(obj))
                pte_flags |= PTE_READ_ONLY;
 
        intel_runtime_pm_get(i915);
@@ -2647,7 +2649,7 @@ static int aliasing_gtt_bind_vma(struct i915_vma *vma,
 
        /* Currently applicable only to VLV */
        pte_flags = 0;
-       if (vma->obj->gt_ro)
+       if (i915_gem_object_is_readonly(vma->obj))
                pte_flags |= PTE_READ_ONLY;
 
        if (flags & I915_VMA_LOCAL_BIND) {