1 files changed, 43 insertions, 0 deletions
diff --git a/roms/edk2/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S b/roms/edk2/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S
new file mode 100644
index 000000000..ee265f94b
--- /dev/null
+++ b/roms/edk2/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S
@@ -0,0 +1,43 @@
+//
+//  Copyright (c) 2012 - 2020, ARM Limited. All rights reserved.
+//
+//  SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+//
+
+.text
+.align 3
+
+GCC_ASM_EXPORT(ArmCallSvc)
+
+ASM_PFX(ArmCallSvc):
+  // Push frame pointer and return address on the stack
+  stp   x29, x30, [sp, #-32]!
+  mov   x29, sp
+
+  // Push x0 on the stack - The stack must always be quad-word aligned
+  str   x0, [sp, #16]
+
+  // Load the SVC arguments values into the appropriate registers
+  ldp   x6, x7, [x0, #48]
+  ldp   x4, x5, [x0, #32]
+  ldp   x2, x3, [x0, #16]
+  ldp   x0, x1, [x0, #0]
+
+  svc   #0
+  // Prevent speculative execution beyond svc instruction
+  dsb   nsh
+  isb
+
+  // Pop the ARM_SVC_ARGS structure address from the stack into x9
+  ldr   x9, [sp, #16]
+
+  // Store the SVC returned values into the ARM_SVC_ARGS structure.
+  // A SVC call can return up to 4 values - we do not need to store back x4-x7.
+  stp   x0, x1, [x9, #0]
+  stp   x2, x3, [x9, #16]
+
+  mov   x0, x9
+
+  ldp   x29, x30, [sp], #32
+  ret