1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_memcpy.c b/drivers/gpu/drm/i915/i915_memcpy.c
new file mode 100644
index 000000000..79f8ec756
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_memcpy.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <asm/fpu/api.h>
+
+#include "i915_drv.h"
+
+static DEFINE_STATIC_KEY_FALSE(has_movntdqa);
+
+#ifdef CONFIG_AS_MOVNTDQA
+static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len)
+{
+	kernel_fpu_begin();
+
+	len >>= 4;
+	while (len >= 4) {
+		asm("movntdqa   (%0), %%xmm0\n"
+		    "movntdqa 16(%0), %%xmm1\n"
+		    "movntdqa 32(%0), %%xmm2\n"
+		    "movntdqa 48(%0), %%xmm3\n"
+		    "movaps %%xmm0,   (%1)\n"
+		    "movaps %%xmm1, 16(%1)\n"
+		    "movaps %%xmm2, 32(%1)\n"
+		    "movaps %%xmm3, 48(%1)\n"
+		    :: "r" (src), "r" (dst) : "memory");
+		src += 64;
+		dst += 64;
+		len -= 4;
+	}
+	while (len--) {
+		asm("movntdqa (%0), %%xmm0\n"
+		    "movaps %%xmm0, (%1)\n"
+		    :: "r" (src), "r" (dst) : "memory");
+		src += 16;
+		dst += 16;
+	}
+
+	kernel_fpu_end();
+}
+#endif
+
+/**
+ * i915_memcpy_from_wc: perform an accelerated *aligned* read from WC
+ * @dst: destination pointer
+ * @src: source pointer
+ * @len: how many bytes to copy
+ *
+ * i915_memcpy_from_wc copies @len bytes from @src to @dst using
+ * non-temporal instructions where available. Note that all arguments
+ * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple
+ * of 16.
+ *
+ * To test whether accelerated reads from WC are supported, use
+ * i915_memcpy_from_wc(NULL, NULL, 0);
+ *
+ * Returns true if the copy was successful, false if the preconditions
+ * are not met.
+ */
+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;
+
+#ifdef CONFIG_AS_MOVNTDQA
+	if (static_branch_likely(&has_movntdqa)) {
+		if (likely(len))
+			__memcpy_ntdqa(dst, src, len);
+		return true;
+	}
+#endif
+
+	return false;
+}
+
+void i915_memcpy_init_early(struct drm_i915_private *dev_priv)
+{
+	/*
+	 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions
+	 * emulation. So don't enable movntdqa in hypervisor guest.
+	 */
+	if (static_cpu_has(X86_FEATURE_XMM4_1) &&
+	    !boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		static_branch_enable(&has_movntdqa);
+}