1/* 2 * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * Redistributions of source code must retain the above copyright notice, this 8 * list of conditions and the following disclaimer. 9 * 10 * Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 14 * Neither the name of ARM nor the names of its contributors may be used 15 * to endorse or promote products derived from this software without specific 16 * prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include <asm_macros.S> 32#include "tspd_private.h" 33 34 .global tspd_enter_sp 35 /* --------------------------------------------- 36 * This function is called with SP_EL0 as stack. 37 * Here we stash our EL3 callee-saved registers 38 * on to the stack as a part of saving the C 39 * runtime and enter the secure payload. 40 * 'x0' contains a pointer to the memory where 41 * the address of the C runtime context is to be 42 * saved. 43 * --------------------------------------------- 44 */ 45func tspd_enter_sp 46 /* Make space for the registers that we're going to save */ 47 mov x3, sp 48 str x3, [x0, #0] 49 sub sp, sp, #TSPD_C_RT_CTX_SIZE 50 51 /* Save callee-saved registers on to the stack */ 52 stp x19, x20, [sp, #TSPD_C_RT_CTX_X19] 53 stp x21, x22, [sp, #TSPD_C_RT_CTX_X21] 54 stp x23, x24, [sp, #TSPD_C_RT_CTX_X23] 55 stp x25, x26, [sp, #TSPD_C_RT_CTX_X25] 56 stp x27, x28, [sp, #TSPD_C_RT_CTX_X27] 57 stp x29, x30, [sp, #TSPD_C_RT_CTX_X29] 58 59 /* --------------------------------------------- 60 * Everything is setup now. el3_exit() will 61 * use the secure context to restore to the 62 * general purpose and EL3 system registers to 63 * ERET into the secure payload. 64 * --------------------------------------------- 65 */ 66 b el3_exit 67endfunc tspd_enter_sp 68 69 /* --------------------------------------------- 70 * This function is called 'x0' pointing to a C 71 * runtime context saved in tspd_enter_sp(). It 72 * restores the saved registers and jumps to 73 * that runtime with 'x0' as the new sp. This 74 * destroys the C runtime context that had been 75 * built on the stack below the saved context by 76 * the caller. Later the second parameter 'x1' 77 * is passed as return value to the caller 78 * --------------------------------------------- 79 */ 80 .global tspd_exit_sp 81func tspd_exit_sp 82 /* Restore the previous stack */ 83 mov sp, x0 84 85 /* Restore callee-saved registers on to the stack */ 86 ldp x19, x20, [x0, #(TSPD_C_RT_CTX_X19 - TSPD_C_RT_CTX_SIZE)] 87 ldp x21, x22, [x0, #(TSPD_C_RT_CTX_X21 - TSPD_C_RT_CTX_SIZE)] 88 ldp x23, x24, [x0, #(TSPD_C_RT_CTX_X23 - TSPD_C_RT_CTX_SIZE)] 89 ldp x25, x26, [x0, #(TSPD_C_RT_CTX_X25 - TSPD_C_RT_CTX_SIZE)] 90 ldp x27, x28, [x0, #(TSPD_C_RT_CTX_X27 - TSPD_C_RT_CTX_SIZE)] 91 ldp x29, x30, [x0, #(TSPD_C_RT_CTX_X29 - TSPD_C_RT_CTX_SIZE)] 92 93 /* --------------------------------------------- 94 * This should take us back to the instruction 95 * after the call to the last tspd_enter_sp(). 96 * Place the second parameter to x0 so that the 97 * caller will see it as a return value from the 98 * original entry call 99 * --------------------------------------------- 100 */ 101 mov x0, x1 102 ret 103endfunc tspd_exit_sp 104