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81 lines
2.7 KiB
81 lines
2.7 KiB
/*
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* Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <asm_macros.S>
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#include "tlkd_private.h"
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.global tlkd_enter_sp
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.global tlkd_exit_sp
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/* ---------------------------------------------
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* This function is called with SP_EL0 as stack.
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* Here we stash our EL3 callee-saved registers
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* on to the stack as a part of saving the C
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* runtime and enter the secure payload.
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* 'x0' contains a pointer to the memory where
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* the address of the C runtime context is to be
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* saved.
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* ---------------------------------------------
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*/
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func tlkd_enter_sp
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/* Make space for the registers that we're going to save */
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mov x3, sp
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str x3, [x0, #0]
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sub sp, sp, #TLKD_C_RT_CTX_SIZE
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/* Save callee-saved registers on to the stack */
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stp x19, x20, [sp, #TLKD_C_RT_CTX_X19]
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stp x21, x22, [sp, #TLKD_C_RT_CTX_X21]
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stp x23, x24, [sp, #TLKD_C_RT_CTX_X23]
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stp x25, x26, [sp, #TLKD_C_RT_CTX_X25]
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stp x27, x28, [sp, #TLKD_C_RT_CTX_X27]
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stp x29, x30, [sp, #TLKD_C_RT_CTX_X29]
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/* ----------------------------------------------
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* Everything is setup now. el3_exit() will
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* use the secure context to restore to the
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* general purpose and EL3 system registers to
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* ERET into the secure payload.
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* ----------------------------------------------
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*/
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b el3_exit
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endfunc tlkd_enter_sp
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/* ----------------------------------------------
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* This function is called with 'x0' pointing to
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* a C runtime context saved in tlkd_enter_sp().
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* It restores the saved registers and jumps to
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* that runtime with 'x0' as the new sp. This
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* destroys the C runtime context that had been
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* built on the stack below the saved context by
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* the caller. Later the second parameter 'x1'
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* is passed as return value to the caller
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* ----------------------------------------------
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*/
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func tlkd_exit_sp
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/* Restore the previous stack */
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mov sp, x0
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/* Restore callee-saved registers on to the stack */
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ldp x19, x20, [x0, #(TLKD_C_RT_CTX_X19 - TLKD_C_RT_CTX_SIZE)]
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ldp x21, x22, [x0, #(TLKD_C_RT_CTX_X21 - TLKD_C_RT_CTX_SIZE)]
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ldp x23, x24, [x0, #(TLKD_C_RT_CTX_X23 - TLKD_C_RT_CTX_SIZE)]
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ldp x25, x26, [x0, #(TLKD_C_RT_CTX_X25 - TLKD_C_RT_CTX_SIZE)]
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ldp x27, x28, [x0, #(TLKD_C_RT_CTX_X27 - TLKD_C_RT_CTX_SIZE)]
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ldp x29, x30, [x0, #(TLKD_C_RT_CTX_X29 - TLKD_C_RT_CTX_SIZE)]
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/* ------------------------------------------------
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* This should take us back to the instruction
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* after the call to the last tlkd_enter_sp().
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* Place the second parameter to x0 so that the
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* caller will see it as a return value from the
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* original entry call
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* ------------------------------------------------
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*/
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mov x0, x1
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ret
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endfunc tlkd_exit_sp
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