MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2009-2013, ARM Ltd.  All rights reserved.
   4 # SPDX-License-Identifier: BSD-2-Clause-Patent
   5 #
   6 #------------------------------------------------------------------------------
   7 .text
   8 .p2align 3
   9
  10 GCC_ASM_EXPORT(SetJump)
  11 GCC_ASM_EXPORT(InternalLongJump)
  12
  13 #define GPR_LAYOUT                         \
  14         REG_PAIR (x19, x20,  0);           \
  15         REG_PAIR (x21, x22, 16);           \
  16         REG_PAIR (x23, x24, 32);           \
  17         REG_PAIR (x25, x26, 48);           \
  18         REG_PAIR (x27, x28, 64);           \
  19         REG_PAIR (x29, x30, 80);/*FP, LR*/ \
  20         REG_ONE  (x16,      96) /*IP0*/
  21
  22 #define FPR_LAYOUT                      \
  23         REG_PAIR ( d8,  d9, 112);       \
  24         REG_PAIR (d10, d11, 128);       \
  25         REG_PAIR (d12, d13, 144);       \
  26         REG_PAIR (d14, d15, 160);
  27
  28 #/**
  29 #  Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
  30 #
  31 #  Saves the current CPU context in the buffer specified by JumpBuffer and returns 0.  The initial
  32 #  call to SetJump() must always return 0.  Subsequent calls to LongJump() cause a non-zero
  33 #  value to be returned by SetJump().
  34 #
  35 #  If JumpBuffer is NULL, then ASSERT().
  36 #  For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
  37 #
  38 #  @param  JumpBuffer    A pointer to CPU context buffer.
  39 #
  40 #**/
  41 #
  42 #UINTN
  43 #EFIAPI
  44 #SetJump (
  45 #  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer  // X0
  46 #  );
  47 #
  48 ASM_PFX(SetJump):
  49         mov     x16, sp // use IP0 so save SP
  50 #define REG_PAIR(REG1, REG2, OFFS)      stp REG1, REG2, [x0, OFFS]
  51 #define REG_ONE(REG1, OFFS)             str REG1, [x0, OFFS]
  52         GPR_LAYOUT
  53         FPR_LAYOUT
  54 #undef REG_PAIR
  55 #undef REG_ONE
  56         mov     w0, #0
  57         ret
  58
  59 #/**
  60 #  Restores the CPU context that was saved with SetJump().#
  61 #
  62 #  Restores the CPU context from the buffer specified by JumpBuffer.
  63 #  This function never returns to the caller.
  64 #  Instead is resumes execution based on the state of JumpBuffer.
  65 #
  66 #  @param  JumpBuffer    A pointer to CPU context buffer.
  67 #  @param  Value         The value to return when the SetJump() context is restored.
  68 #
  69 #**/
  70 #VOID
  71 #EFIAPI
  72 #InternalLongJump (
  73 #  IN      BASE_LIBRARY_JUMP_BUFFER  *JumpBuffer,  // X0
  74 #  IN      UINTN                     Value         // X1
  75 #  );
  76 #
  77 ASM_PFX(InternalLongJump):
  78 #define REG_PAIR(REG1, REG2, OFFS)      ldp REG1, REG2, [x0, OFFS]
  79 #define REG_ONE(REG1, OFFS)             ldr REG1, [x0, OFFS]
  80         GPR_LAYOUT
  81         FPR_LAYOUT
  82 #undef REG_PAIR
  83 #undef REG_ONE
  84         mov     sp, x16
  85         cmp     w1, #0
  86         mov     w0, #1
  87         csel    w0, w1, w0, ne
  88         // use br not ret, as ret is guaranteed to mispredict
  89         br      x30
  90
  91 ASM_FUNCTION_REMOVE_IF_UNREFERENCED