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/*
* Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <asm_macros.S>
#include "opteed_private.h"
.global opteed_enter_sp
/* ---------------------------------------------
* This function is called with SP_EL0 as stack.
* Here we stash our EL3 callee-saved registers
* on to the stack as a part of saving the C
* runtime and enter the secure payload.
* 'x0' contains a pointer to the memory where
* the address of the C runtime context is to be
* saved.
* ---------------------------------------------
*/
func opteed_enter_sp
/* Make space for the registers that we're going to save */
mov x3, sp
str x3, [x0, #0]
sub sp, sp, #OPTEED_C_RT_CTX_SIZE
/* Save callee-saved registers on to the stack */
stp x19, x20, [sp, #OPTEED_C_RT_CTX_X19]
stp x21, x22, [sp, #OPTEED_C_RT_CTX_X21]
stp x23, x24, [sp, #OPTEED_C_RT_CTX_X23]
stp x25, x26, [sp, #OPTEED_C_RT_CTX_X25]
stp x27, x28, [sp, #OPTEED_C_RT_CTX_X27]
stp x29, x30, [sp, #OPTEED_C_RT_CTX_X29]
/* ---------------------------------------------
* Everything is setup now. el3_exit() will
* use the secure context to restore to the
* general purpose and EL3 system registers to
* ERET into OPTEE.
* ---------------------------------------------
*/
b el3_exit
/* ---------------------------------------------
* This function is called 'x0' pointing to a C
* runtime context saved in opteed_enter_sp(). It
* restores the saved registers and jumps to
* that runtime with 'x0' as the new sp. This
* destroys the C runtime context that had been
* built on the stack below the saved context by
* the caller. Later the second parameter 'x1'
* is passed as return value to the caller
* ---------------------------------------------
*/
.global opteed_exit_sp
func opteed_exit_sp
/* Restore the previous stack */
mov sp, x0
/* Restore callee-saved registers on to the stack */
ldp x19, x20, [x0, #(OPTEED_C_RT_CTX_X19 - OPTEED_C_RT_CTX_SIZE)]
ldp x21, x22, [x0, #(OPTEED_C_RT_CTX_X21 - OPTEED_C_RT_CTX_SIZE)]
ldp x23, x24, [x0, #(OPTEED_C_RT_CTX_X23 - OPTEED_C_RT_CTX_SIZE)]
ldp x25, x26, [x0, #(OPTEED_C_RT_CTX_X25 - OPTEED_C_RT_CTX_SIZE)]
ldp x27, x28, [x0, #(OPTEED_C_RT_CTX_X27 - OPTEED_C_RT_CTX_SIZE)]
ldp x29, x30, [x0, #(OPTEED_C_RT_CTX_X29 - OPTEED_C_RT_CTX_SIZE)]
/* ---------------------------------------------
* This should take us back to the instruction
* after the call to the last opteed_enter_sp().
* Place the second parameter to x0 so that the
* caller will see it as a return value from the
* original entry call
* ---------------------------------------------
*/
mov x0, x1
ret
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