From 8a4cb9cc8a8bf0fa8c85159c6b908f097cd94825 Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Mon, 31 Oct 2016 15:02:18 +0200 Subject: [PATCH 1/2] drm/i915/gtt: Fix pte clear range MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Comparing pte index to a number of entries is wrong when clearing a range of pte entries. Use end marker of 'one past' to correctly point adequate number of ptes to the scratch page. v2: assert early instead of warning late (Chris) Fixes: d209b9c3cd28 ("drm/i915/gtt: Split gen8_ppgtt_clear_pte_range") References: https://bugs.freedesktop.org/show_bug.cgi?id=98282 Cc: Chris Wilson Cc: Joonas Lahtinen Cc: Michel Thierry Cc: Michał Winiarski Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/i915_gem_gtt.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index e7afad5..5f5008f 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -712,13 +712,13 @@ static int gen8_48b_mm_switch(struct i915_hw_ppgtt *ppgtt, */ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm, struct i915_page_table *pt, - uint64_t start, - uint64_t length) + const uint64_t start, + const uint64_t length) { struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm); - unsigned int pte_start = gen8_pte_index(start); - unsigned int num_entries = gen8_pte_count(start, length); - uint64_t pte; + const unsigned int num_entries = gen8_pte_count(start, length); + unsigned int pte = gen8_pte_index(start); + unsigned int pte_end = pte + num_entries; gen8_pte_t *pt_vaddr; gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC); @@ -726,7 +726,9 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm, if (WARN_ON(!px_page(pt))) return false; - bitmap_clear(pt->used_ptes, pte_start, num_entries); + GEM_BUG_ON(pte_end > GEN8_PTES); + + bitmap_clear(pt->used_ptes, pte, num_entries); if (bitmap_empty(pt->used_ptes, GEN8_PTES)) { free_pt(vm->dev, pt); @@ -735,8 +737,8 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm, pt_vaddr = kmap_px(pt); - for (pte = pte_start; pte < num_entries; pte++) - pt_vaddr[pte] = scratch_pte; + while (pte < pte_end) + pt_vaddr[pte++] = scratch_pte; kunmap_px(ppgtt, pt_vaddr); -- 2.7.4