From 5a8e9943528dd84315db2e9dfd7330bcbb872414 Mon Sep 17 00:00:00 2001 From: Michel Thierry Date: Wed, 8 Apr 2015 12:13:25 +0100 Subject: [PATCH] drm/i915/gen8: Initialize page tables Similar to gen6, while setting up a page table, make all entries of the pt point to the scratch page before mapping; this is to be safe in case of out of bound access or proactive prefetch. Systems without LLC require an explicit flush. v2: Expanded commit text and fixed indentation (Mika) Signed-off-by: Michel Thierry Reviewed-by: Mika Kuoppala Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem_gtt.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index a7d364ae0518..c2045bd45e5e 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -332,6 +332,24 @@ static void unmap_and_free_pt(struct i915_page_table *pt, kfree(pt); } +static void gen8_initialize_pt(struct i915_address_space *vm, + struct i915_page_table *pt) +{ + gen8_pte_t *pt_vaddr, scratch_pte; + int i; + + pt_vaddr = kmap_atomic(pt->page); + scratch_pte = gen8_pte_encode(vm->scratch.addr, + I915_CACHE_LLC, true); + + for (i = 0; i < GEN8_PTES; i++) + pt_vaddr[i] = scratch_pte; + + if (!HAS_LLC(vm->dev)) + drm_clflush_virt_range(pt_vaddr, PAGE_SIZE); + kunmap_atomic(pt_vaddr); +} + static struct i915_page_table *alloc_pt_single(struct drm_device *dev) { struct i915_page_table *pt; @@ -429,7 +447,7 @@ static struct i915_page_directory *alloc_pd_single(void) if (!pd) return ERR_PTR(-ENOMEM); - pd->page = alloc_page(GFP_KERNEL | __GFP_ZERO); + pd->page = alloc_page(GFP_KERNEL); if (!pd->page) { kfree(pd); return ERR_PTR(-ENOMEM); @@ -719,6 +737,8 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt, struct page *p = ptab->page; int ret; + gen8_initialize_pt(&ppgtt->base, ptab); + pt_addr = pci_map_page(ppgtt->base.dev->pdev, p, 0, PAGE_SIZE, PCI_DMA_BIDIRECTIONAL); ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pt_addr); -- 2.34.1