1aa5da461SJens Wiklander/* 2aa5da461SJens Wiklander * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. 3aa5da461SJens Wiklander * 4*82cb2c1aSdp-arm * SPDX-License-Identifier: BSD-3-Clause 5aa5da461SJens Wiklander */ 6aa5da461SJens Wiklander 7aa5da461SJens Wiklander#include <asm_macros.S> 8aa5da461SJens Wiklander#include "opteed_private.h" 9aa5da461SJens Wiklander 10aa5da461SJens Wiklander .global opteed_enter_sp 11aa5da461SJens Wiklander /* --------------------------------------------- 12aa5da461SJens Wiklander * This function is called with SP_EL0 as stack. 13aa5da461SJens Wiklander * Here we stash our EL3 callee-saved registers 14aa5da461SJens Wiklander * on to the stack as a part of saving the C 15aa5da461SJens Wiklander * runtime and enter the secure payload. 16aa5da461SJens Wiklander * 'x0' contains a pointer to the memory where 17aa5da461SJens Wiklander * the address of the C runtime context is to be 18aa5da461SJens Wiklander * saved. 19aa5da461SJens Wiklander * --------------------------------------------- 20aa5da461SJens Wiklander */ 21aa5da461SJens Wiklanderfunc opteed_enter_sp 22aa5da461SJens Wiklander /* Make space for the registers that we're going to save */ 23aa5da461SJens Wiklander mov x3, sp 24aa5da461SJens Wiklander str x3, [x0, #0] 25aa5da461SJens Wiklander sub sp, sp, #OPTEED_C_RT_CTX_SIZE 26aa5da461SJens Wiklander 27aa5da461SJens Wiklander /* Save callee-saved registers on to the stack */ 28aa5da461SJens Wiklander stp x19, x20, [sp, #OPTEED_C_RT_CTX_X19] 29aa5da461SJens Wiklander stp x21, x22, [sp, #OPTEED_C_RT_CTX_X21] 30aa5da461SJens Wiklander stp x23, x24, [sp, #OPTEED_C_RT_CTX_X23] 31aa5da461SJens Wiklander stp x25, x26, [sp, #OPTEED_C_RT_CTX_X25] 32aa5da461SJens Wiklander stp x27, x28, [sp, #OPTEED_C_RT_CTX_X27] 33aa5da461SJens Wiklander stp x29, x30, [sp, #OPTEED_C_RT_CTX_X29] 34aa5da461SJens Wiklander 35aa5da461SJens Wiklander /* --------------------------------------------- 36aa5da461SJens Wiklander * Everything is setup now. el3_exit() will 37aa5da461SJens Wiklander * use the secure context to restore to the 38aa5da461SJens Wiklander * general purpose and EL3 system registers to 39aa5da461SJens Wiklander * ERET into OPTEE. 40aa5da461SJens Wiklander * --------------------------------------------- 41aa5da461SJens Wiklander */ 42aa5da461SJens Wiklander b el3_exit 438b779620SKévin Petitendfunc opteed_enter_sp 44aa5da461SJens Wiklander 45aa5da461SJens Wiklander /* --------------------------------------------- 46aa5da461SJens Wiklander * This function is called 'x0' pointing to a C 47aa5da461SJens Wiklander * runtime context saved in opteed_enter_sp(). It 48aa5da461SJens Wiklander * restores the saved registers and jumps to 49aa5da461SJens Wiklander * that runtime with 'x0' as the new sp. This 50aa5da461SJens Wiklander * destroys the C runtime context that had been 51aa5da461SJens Wiklander * built on the stack below the saved context by 52aa5da461SJens Wiklander * the caller. Later the second parameter 'x1' 53aa5da461SJens Wiklander * is passed as return value to the caller 54aa5da461SJens Wiklander * --------------------------------------------- 55aa5da461SJens Wiklander */ 56aa5da461SJens Wiklander .global opteed_exit_sp 57aa5da461SJens Wiklanderfunc opteed_exit_sp 58aa5da461SJens Wiklander /* Restore the previous stack */ 59aa5da461SJens Wiklander mov sp, x0 60aa5da461SJens Wiklander 61aa5da461SJens Wiklander /* Restore callee-saved registers on to the stack */ 62aa5da461SJens Wiklander ldp x19, x20, [x0, #(OPTEED_C_RT_CTX_X19 - OPTEED_C_RT_CTX_SIZE)] 63aa5da461SJens Wiklander ldp x21, x22, [x0, #(OPTEED_C_RT_CTX_X21 - OPTEED_C_RT_CTX_SIZE)] 64aa5da461SJens Wiklander ldp x23, x24, [x0, #(OPTEED_C_RT_CTX_X23 - OPTEED_C_RT_CTX_SIZE)] 65aa5da461SJens Wiklander ldp x25, x26, [x0, #(OPTEED_C_RT_CTX_X25 - OPTEED_C_RT_CTX_SIZE)] 66aa5da461SJens Wiklander ldp x27, x28, [x0, #(OPTEED_C_RT_CTX_X27 - OPTEED_C_RT_CTX_SIZE)] 67aa5da461SJens Wiklander ldp x29, x30, [x0, #(OPTEED_C_RT_CTX_X29 - OPTEED_C_RT_CTX_SIZE)] 68aa5da461SJens Wiklander 69aa5da461SJens Wiklander /* --------------------------------------------- 70aa5da461SJens Wiklander * This should take us back to the instruction 71aa5da461SJens Wiklander * after the call to the last opteed_enter_sp(). 72aa5da461SJens Wiklander * Place the second parameter to x0 so that the 73aa5da461SJens Wiklander * caller will see it as a return value from the 74aa5da461SJens Wiklander * original entry call 75aa5da461SJens Wiklander * --------------------------------------------- 76aa5da461SJens Wiklander */ 77aa5da461SJens Wiklander mov x0, x1 78aa5da461SJens Wiklander ret 798b779620SKévin Petitendfunc opteed_exit_sp 80