hypercall.S 3.6 KB

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  1. /******************************************************************************
  2. * hypercall.S
  3. *
  4. * Xen hypercall wrappers
  5. *
  6. * Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012
  7. *
  8. * This program is free software; you can redistribute it and/or
  9. * modify it under the terms of the GNU General Public License version 2
  10. * as published by the Free Software Foundation; or, when distributed
  11. * separately from the Linux kernel or incorporated into other
  12. * software packages, subject to the following license:
  13. *
  14. * Permission is hereby granted, free of charge, to any person obtaining a copy
  15. * of this source file (the "Software"), to deal in the Software without
  16. * restriction, including without limitation the rights to use, copy, modify,
  17. * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  18. * and to permit persons to whom the Software is furnished to do so, subject to
  19. * the following conditions:
  20. *
  21. * The above copyright notice and this permission notice shall be included in
  22. * all copies or substantial portions of the Software.
  23. *
  24. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  25. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  26. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  27. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  28. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  29. * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  30. * IN THE SOFTWARE.
  31. */
  32. /*
  33. * The Xen hypercall calling convention is very similar to the procedure
  34. * call standard for the ARM 64-bit architecture: the first parameter is
  35. * passed in x0, the second in x1, the third in x2, the fourth in x3 and
  36. * the fifth in x4.
  37. *
  38. * The hypercall number is passed in x16.
  39. *
  40. * The return value is in x0.
  41. *
  42. * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM
  43. * hypercall tag.
  44. *
  45. * Parameter structs passed to hypercalls are laid out according to
  46. * the ARM 64-bit EABI standard.
  47. */
  48. #include <linux/linkage.h>
  49. #include <asm/assembler.h>
  50. #include <asm/asm-uaccess.h>
  51. #include <xen/interface/xen.h>
  52. #define XEN_IMM 0xEA1
  53. #define HYPERCALL_SIMPLE(hypercall) \
  54. SYM_FUNC_START(HYPERVISOR_##hypercall) \
  55. mov x16, #__HYPERVISOR_##hypercall; \
  56. hvc XEN_IMM; \
  57. ret; \
  58. SYM_FUNC_END(HYPERVISOR_##hypercall)
  59. #define HYPERCALL0 HYPERCALL_SIMPLE
  60. #define HYPERCALL1 HYPERCALL_SIMPLE
  61. #define HYPERCALL2 HYPERCALL_SIMPLE
  62. #define HYPERCALL3 HYPERCALL_SIMPLE
  63. #define HYPERCALL4 HYPERCALL_SIMPLE
  64. #define HYPERCALL5 HYPERCALL_SIMPLE
  65. .text
  66. HYPERCALL2(xen_version);
  67. HYPERCALL3(console_io);
  68. HYPERCALL3(grant_table_op);
  69. HYPERCALL2(sched_op);
  70. HYPERCALL2(event_channel_op);
  71. HYPERCALL2(hvm_op);
  72. HYPERCALL2(memory_op);
  73. HYPERCALL2(physdev_op);
  74. HYPERCALL3(vcpu_op);
  75. HYPERCALL1(tmem_op);
  76. HYPERCALL1(platform_op_raw);
  77. HYPERCALL2(multicall);
  78. HYPERCALL2(vm_assist);
  79. HYPERCALL3(dm_op);
  80. SYM_FUNC_START(privcmd_call)
  81. mov x16, x0
  82. mov x0, x1
  83. mov x1, x2
  84. mov x2, x3
  85. mov x3, x4
  86. mov x4, x5
  87. /*
  88. * Privcmd calls are issued by the userspace. The kernel needs to
  89. * enable access to TTBR0_EL1 as the hypervisor would issue stage 1
  90. * translations to user memory via AT instructions. Since AT
  91. * instructions are not affected by the PAN bit (ARMv8.1), we only
  92. * need the explicit uaccess_enable/disable if the TTBR0 PAN emulation
  93. * is enabled (it implies that hardware UAO and PAN disabled).
  94. */
  95. uaccess_ttbr0_enable x6, x7, x8
  96. hvc XEN_IMM
  97. /*
  98. * Disable userspace access from kernel once the hyp call completed.
  99. */
  100. uaccess_ttbr0_disable x6, x7
  101. ret
  102. SYM_FUNC_END(privcmd_call);