| Message ID | 20170130134721.5159-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On ma, 2017-01-30 at 13:47 +0000, Chris Wilson wrote: > 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> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Regards, Joonas
On Tue, Jan 31, 2017 at 12:13:47PM +0200, Joonas Lahtinen wrote: > On ma, 2017-01-30 at 13:47 +0000, Chris Wilson wrote: > > 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> > > Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Applied, thanks, -Chris
diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c index 42bbc4b04fd6..f3abdc27c5dd 100644 --- a/drivers/gpu/drm/i915/i915_gem_stolen.c +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c @@ -189,7 +189,7 @@ static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv) base = tom - tseg_size - ggtt->stolen_size; } - if (base == 0) + if (base == 0 || add_overflows(base, ggtt->stolen_size)) return 0; /* make sure we don't clobber the GTT if it's within stolen memory */ diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index 34020873e1f6..69e00c94ee13 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -25,6 +25,13 @@ #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) ((A) + (B) < (A)) +#endif + #define range_overflows(start, size, max) ({ \ typeof(start) start__ = (start); \ typeof(size) size__ = (size); \
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> --- drivers/gpu/drm/i915/i915_gem_stolen.c | 2 +- drivers/gpu/drm/i915/i915_utils.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-)