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92 lines
2.8 KiB
C++
92 lines
2.8 KiB
C++
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/*
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* Copyright (C) 2011-2016 Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "xsave.h"
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#include "util.h"
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#include "se_detect.h"
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#include "sgx_attributes.h"
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#define XFRM_YMM_BITMASK 0x00000004
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// save_and_clean_xfeature_regs()
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// do fwait, fxsave, and then clear the upper bits of YMM regs before executing EENTER.
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// Parameters:
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// buffer - if the pointer is not NULL, save the CPU state to the buffer
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// Return Value:
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// none
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void save_and_clean_xfeature_regs(uint8_t *buffer)
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{
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// XCR0 is not supposed to be changed. So query it once.
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static uint64_t xcr0 = 0;
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if(xcr0 == 0)
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{
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if(false == try_read_xcr0(&xcr0))
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{
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xcr0 = SGX_XFRM_LEGACY;
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}
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}
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// do fwait to flush the float-point exceptions
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do_fwait();
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// do fxsave to save the CPU state before ecall
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// no need to save the CPU state before oret
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if(buffer != 0)
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{
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uint8_t *buf = (uint8_t*)ROUND_TO((size_t)buffer, FXSAVE_ALIGN_SIZE);
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do_fxsave(buf);
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}
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// clean the upper bits of the YMM regs
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if(xcr0 & XFRM_YMM_BITMASK)
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{
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do_vzeroupper();
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}
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}
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void restore_xfeature_regs(const uint8_t *buffer)
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{
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if (buffer)
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{
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uint8_t *buf = (uint8_t*)ROUND_TO((size_t)buffer, FXSAVE_ALIGN_SIZE);
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do_fxrstor(buf);
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}
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}
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