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ArmPkg/ArmSvcLib: Add ArmSvcLib implementation.

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This patch adds a library that enables invocation of SVCs from Exception
Level EL0. It will be used by the Standalone MM environment to request
services from a software running in a privileged EL e.g. ARM Trusted
Firmware. The library is derived directly from Arm SMC Library.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Supreeth Venkatesh <supreeth.venkatesh@arm.com>

[ardb: assign frame pointer (AArch64)
       keep stack alignment (ARM)]
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This commit is contained in:
Supreeth Venkatesh
2017-09-20 20:48:11 +01:00
committed by Ard Biesheuvel
parent 4d163696f2
commit f8f0e454e1
5 changed files with 156 additions and 0 deletions
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46
ArmPkg/Library/ArmSvcLib/AArch64/ArmSvc.S Normal file
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//
// Copyright (c) 2012 - 2017, ARM Limited. All rights reserved.
//
// This program and the accompanying materials
// are licensed and made available under the terms and conditions of the BSD License
// which accompanies this distribution. The full text of the license may be found at
// http://opensource.org/licenses/bsd-license.php
//
// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
//
//
.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
// 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