ArmPkg/ArmSvcLib: Add ArmSvcLib implementation.

[mirror_edk2.git] / ArmPkg / Library / ArmSvcLib / AArch64 / ArmSvc.S

diff --git a/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S b/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S
new file mode 100644 (file)
index 0000000..7b8e4a9
--- /dev/null
+++ b/ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S
@@ -0,0 +1,46 @@
+//\r
+//  Copyright (c) 2012 - 2017, ARM Limited. All rights reserved.\r
+//\r
+//  This program and the accompanying materials\r
+//  are licensed and made available under the terms and conditions of the BSD License\r
+//  which accompanies this distribution.  The full text of the license may be found at\r
+//  http://opensource.org/licenses/bsd-license.php\r
+//\r
+//  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+//  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+//\r
+//\r
+\r
+.text\r
+.align 3\r
+\r
+GCC_ASM_EXPORT(ArmCallSvc)\r
+\r
+ASM_PFX(ArmCallSvc):\r
+  // Push frame pointer and return address on the stack\r
+  stp   x29, x30, [sp, #-32]!\r
+  mov   x29, sp\r
+\r
+  // Push x0 on the stack - The stack must always be quad-word aligned\r
+  str   x0, [sp, #16]\r
+\r
+  // Load the SVC arguments values into the appropriate registers\r
+  ldp   x6, x7, [x0, #48]\r
+  ldp   x4, x5, [x0, #32]\r
+  ldp   x2, x3, [x0, #16]\r
+  ldp   x0, x1, [x0, #0]\r
+\r
+  svc   #0\r
+\r
+  // Pop the ARM_SVC_ARGS structure address from the stack into x9\r
+  ldr   x9, [sp, #16]\r
+\r
+  // Store the SVC returned values into the ARM_SVC_ARGS structure.\r
+  // A SVC call can return up to 4 values - we do not need to store back x4-x7.\r
+  stp   x0, x1, [x9, #0]\r
+  stp   x2, x3, [x9, #16]\r
+\r
+  mov   x0, x9\r
+\r
+  ldp   x29, x30, [sp], #32\r
+  ret\r