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/*
* 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_memcpy.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);
}
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