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authorChris Wilson <chris@chris-wilson.co.uk>2017-01-30 13:47:21 +0000
committerChris Wilson <chris@chris-wilson.co.uk>2017-01-31 11:19:23 +0000
commit1692cd60d999b00a0491692dab0286e6011abd36 (patch)
tree6ca4aad3e28794cb99b9bdc28dfa993054b6c5f1 /drivers/gpu/drm/i915/i915_utils.h
parentc88473878d47131ccfc67a00ba688d4d7d0f4519 (diff)
downloadlinux-1692cd60d999b00a0491692dab0286e6011abd36.tar.bz2
drm/i915: Sanity check the computed size and base of stolen memory
Just do a quick check that the stolen memory address range doesn't overflow our chosen integer type. v2: Add add_overflows() to utils with the promise that gcc7 can do this better than C and then maybe it will have a proper definition in core. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170130134721.5159-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_utils.h')
-rw-r--r--drivers/gpu/drm/i915/i915_utils.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 34020873e1f6..b8ba0f2f92af 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -25,6 +25,17 @@
#ifndef __I915_UTILS_H
#define __I915_UTILS_H
+#if GCC_VERSION >= 70000
+#define add_overflows(A, B) \
+ __builtin_add_overflow_p((A), (B), (typeof((A) + (B)))0)
+#else
+#define add_overflows(A, B) ({ \
+ typeof(A) a = (A); \
+ typeof(B) b = (B); \
+ a + b < a; \
+})
+#endif
+
#define range_overflows(start, size, max) ({ \
typeof(start) start__ = (start); \
typeof(size) size__ = (size); \