On Sun, May 3, 2020 at 2:31 PM Chris Wilson chris@chris-wilson.co.uk wrote:

Query whether or not we are in a legal context for using SIMD, before using SSE4.2 registers.

Suggested-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Chris Wilson chris@chris-wilson.co.uk

---

drivers/gpu/drm/i915/i915_memcpy.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_memcpy.c b/drivers/gpu/drm/i915/i915_memcpy.c index 7b3b83bd5ab8..fc18d6c28d5f 100644 --- a/drivers/gpu/drm/i915/i915_memcpy.c +++ b/drivers/gpu/drm/i915/i915_memcpy.c @@ -24,6 +24,7 @@

#include <linux/kernel.h> #include <asm/fpu/api.h> +#include <asm/simd.h>

#include "i915_memcpy.h"

@@ -115,6 +116,9 @@ bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len) if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) return false;

•   if (unlikely(!may_use_simd()))
  

•           return false;
  

•   if (static_branch_likely(&has_movntdqa)) {
            if (likely(len))
                    __memcpy_ntdqa(dst, src, len >> 4);
  

-- 2.20.1

Looks like you beat me to the punch. Thanks for doing this.

Reviewed-by: Jason A. Donenfeld Jason@zx2c4.com