From 322307a28311d07762d8c6a69be8ec29034b1c02 Mon Sep 17 00:00:00 2001
From: Michel Thierry <michel.thierry@intel.com>
Date: Thu, 30 Apr 2015 16:06:51 +0100
Subject: [PATCH] drm/i915: Fix 32b overflow check in
gen8_ppgtt_alloc_page_directories
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The patch 56f1ad7ad61e1d2bf48ec7311ba6c47a0fb8c0a1: "drm/i915/gen8:
page directories rework allocation" added an overflow warning, but the
mask had an extra 0. Use less typo-prone option suggested by Dave
instead, to check for (start + length) >= 0x100000000ULL.
This check will be unnecessary after gen8_alloc_va_range handles more
than 4 PDPs (48b addressing).
v2: Really check for 32b overflow (Ville)
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index ce91314f2c0c9..8fee6789fae2d 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -756,8 +756,8 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
WARN_ON(!bitmap_empty(new_pds, GEN8_LEGACY_PDPES));
- /* FIXME: PPGTT container_of won't work for 64b */
- WARN_ON((start + length) > 0x800000000ULL);
+ /* FIXME: upper bound must not overflow 32 bits */
+ WARN_ON((start + length) >= (1ULL << 32));
gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
if (pd)
--
2.39.5