107 lines
3.1 KiB
C
107 lines
3.1 KiB
C
/*
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* Copyright © 2016 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <linux/kernel.h>
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#include <asm/fpu/api.h>
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#include "i915_memcpy.h"
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static DEFINE_STATIC_KEY_FALSE(has_movntdqa);
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#ifdef CONFIG_AS_MOVNTDQA
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static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len)
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{
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kernel_fpu_begin();
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len >>= 4;
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while (len >= 4) {
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asm("movntdqa (%0), %%xmm0\n"
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"movntdqa 16(%0), %%xmm1\n"
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"movntdqa 32(%0), %%xmm2\n"
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"movntdqa 48(%0), %%xmm3\n"
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"movaps %%xmm0, (%1)\n"
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"movaps %%xmm1, 16(%1)\n"
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"movaps %%xmm2, 32(%1)\n"
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"movaps %%xmm3, 48(%1)\n"
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:: "r" (src), "r" (dst) : "memory");
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src += 64;
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dst += 64;
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len -= 4;
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}
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while (len--) {
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asm("movntdqa (%0), %%xmm0\n"
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"movaps %%xmm0, (%1)\n"
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:: "r" (src), "r" (dst) : "memory");
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src += 16;
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dst += 16;
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}
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kernel_fpu_end();
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}
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#endif
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/**
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* i915_memcpy_from_wc: perform an accelerated *aligned* read from WC
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* @dst: destination pointer
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* @src: source pointer
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* @len: how many bytes to copy
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*
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* i915_memcpy_from_wc copies @len bytes from @src to @dst using
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* non-temporal instructions where available. Note that all arguments
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* (@src, @dst) must be aligned to 16 bytes and @len must be a multiple
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* of 16.
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*
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* To test whether accelerated reads from WC are supported, use
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* i915_memcpy_from_wc(NULL, NULL, 0);
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*
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* Returns true if the copy was successful, false if the preconditions
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* are not met.
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*/
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bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len)
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{
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if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15))
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return false;
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#ifdef CONFIG_AS_MOVNTDQA
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if (static_branch_likely(&has_movntdqa)) {
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if (likely(len))
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__memcpy_ntdqa(dst, src, len);
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return true;
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}
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#endif
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return false;
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}
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void i915_memcpy_init_early(struct drm_i915_private *dev_priv)
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{
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/*
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* Some hypervisors (e.g. KVM) don't support VEX-prefix instructions
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* emulation. So don't enable movntdqa in hypervisor guest.
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*/
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if (static_cpu_has(X86_FEATURE_XMM4_1) &&
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!boot_cpu_has(X86_FEATURE_HYPERVISOR))
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static_branch_enable(&has_movntdqa);
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}
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