linux-sgx-trts-modified/sdk/trts/trts_xsave.cpp

/*
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 * modification, are permitted provided that the following conditions
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 *     notice, this list of conditions and the following disclaimer.
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 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#include "arch.h"
#include "xsave.h"
#include "trts_inst.h"
#include "util.h"
#include "global_data.h"
#include "stdlib.h"

#define SYNTHETIC_STATE_SIZE   (512 + 64)  // 512 for legacy regs, 64 for xsave header
//FXRSTOR only cares about the first 512 bytes, while
//XRSTOR in compacted mode will ignore the first 512 bytes.
extern "C" SE_DECLSPEC_ALIGN(XSAVE_ALIGN_SIZE) const uint32_t
SYNTHETIC_STATE[SYNTHETIC_STATE_SIZE/sizeof(uint32_t)] = {
    0x037F, 0, 0, 0, 0, 0, 0x1F80, 0xFFFF, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0x80000000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,   // XCOMP_BV[63] = 1, compaction mode
};

int g_xsave_enabled;             // flag to indicate whether xsave is enabled or not

// EENTER will set xcr0 with secs.attr.xfrm, 
// So use the xfeature mask from report instead of calling xgetbv
#ifdef __clang__
#define SE_OPTIMIZE_OFF [[clang::optnone]]
#else
#define SE_OPTIMIZE_OFF
#endif

SE_OPTIMIZE_OFF
uint64_t get_xfeature_state()
{
    assert (REPORT_ALIGN_SIZE >= REPORT_DATA_ALIGN_SIZE);
    assert (REPORT_ALIGN_SIZE >= TARGET_INFO_ALIGN_SIZE);

    // target_info and report_data are useless
    // we only need to make sure their alignment and within enclave
    uint8_t buffer[sizeof(sgx_report_t) + REPORT_ALIGN_SIZE -1];
    for(size_t i=0; i< sizeof(sgx_report_t) + REPORT_ALIGN_SIZE -1; i++)
    {
        buffer[i] = 0;
    }
    sgx_report_t *report = (sgx_report_t *)ROUND_TO((size_t)buffer, REPORT_ALIGN_SIZE);
    sgx_target_info_t *target_info = (sgx_target_info_t *)report;
    sgx_report_data_t *report_data = (sgx_report_data_t *)report;


    do_ereport(target_info, report_data, report);

    g_xsave_enabled = (report->body.attributes.xfrm == SGX_XFRM_LEGACY) ? 0 : 1;
    uint64_t xfrm = report->body.attributes.xfrm;

    // no secrets in target_info, report_data, and report. no need to clear them before return
    // tlibc functions cannot be used before calling init_optimized_libs().

    return xfrm;
}