urts_xsave.cpp 2.8 KB

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  1. /*
  2. * Copyright (C) 2011-2017 Intel Corporation. All rights reserved.
  3. *
  4. * Redistribution and use in source and binary forms, with or without
  5. * modification, are permitted provided that the following conditions
  6. * are met:
  7. *
  8. * * Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * * Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in
  12. * the documentation and/or other materials provided with the
  13. * distribution.
  14. * * Neither the name of Intel Corporation nor the names of its
  15. * contributors may be used to endorse or promote products derived
  16. * from this software without specific prior written permission.
  17. *
  18. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21. * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22. * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25. * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26. * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28. * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29. *
  30. */
  31. #include "xsave.h"
  32. #include "util.h"
  33. #include "se_detect.h"
  34. #include "sgx_attributes.h"
  35. #define XFRM_YMM_BITMASK 0x00000004
  36. // save_and_clean_xfeature_regs()
  37. // do fwait, fxsave, and then clear the upper bits of YMM regs before executing EENTER.
  38. // Parameters:
  39. // buffer - if the pointer is not NULL, save the CPU state to the buffer
  40. // Return Value:
  41. // none
  42. void save_and_clean_xfeature_regs(uint8_t *buffer)
  43. {
  44. // XCR0 is not supposed to be changed. So query it once.
  45. static uint64_t xcr0 = 0;
  46. if(xcr0 == 0)
  47. {
  48. if(false == try_read_xcr0(&xcr0))
  49. {
  50. xcr0 = SGX_XFRM_LEGACY;
  51. }
  52. }
  53. // do fwait to flush the float-point exceptions
  54. do_fwait();
  55. // do fxsave to save the CPU state before ecall
  56. // no need to save the CPU state before oret
  57. if(buffer != 0)
  58. {
  59. uint8_t *buf = (uint8_t*)ROUND_TO((size_t)buffer, FXSAVE_ALIGN_SIZE);
  60. do_fxsave(buf);
  61. }
  62. // clean the upper bits of the YMM regs
  63. if(xcr0 & XFRM_YMM_BITMASK)
  64. {
  65. do_vzeroupper();
  66. }
  67. }
  68. void restore_xfeature_regs(const uint8_t *buffer)
  69. {
  70. if (buffer)
  71. {
  72. uint8_t *buf = (uint8_t*)ROUND_TO((size_t)buffer, FXSAVE_ALIGN_SIZE);
  73. do_fxrstor(buf);
  74. }
  75. }