1/* 2 * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7#include <asm_macros.S> 8#include "../spm_mm_private.h" 9 10 .global spm_secure_partition_enter 11 .global spm_secure_partition_exit 12 13 /* --------------------------------------------------------------------- 14 * This function is called with SP_EL0 as stack. Here we stash our EL3 15 * callee-saved registers on to the stack as a part of saving the C 16 * runtime and enter the secure payload. 17 * 'x0' contains a pointer to the memory where the address of the C 18 * runtime context is to be saved. 19 * --------------------------------------------------------------------- 20 */ 21func spm_secure_partition_enter 22 /* Make space for the registers that we're going to save */ 23 mov x3, sp 24 str x3, [x0, #0] 25 sub sp, sp, #SP_C_RT_CTX_SIZE 26 27 /* Save callee-saved registers on to the stack */ 28 stp x19, x20, [sp, #SP_C_RT_CTX_X19] 29 stp x21, x22, [sp, #SP_C_RT_CTX_X21] 30 stp x23, x24, [sp, #SP_C_RT_CTX_X23] 31 stp x25, x26, [sp, #SP_C_RT_CTX_X25] 32 stp x27, x28, [sp, #SP_C_RT_CTX_X27] 33 stp x29, x30, [sp, #SP_C_RT_CTX_X29] 34 35 /* --------------------------------------------------------------------- 36 * Everything is setup now. el3_exit() will use the secure context to 37 * restore to the general purpose and EL3 system registers to ERET 38 * into the secure payload. 39 * --------------------------------------------------------------------- 40 */ 41 b el3_exit 42endfunc spm_secure_partition_enter 43 44 /* --------------------------------------------------------------------- 45 * This function is called with 'x0' pointing to a C runtime context 46 * saved in spm_secure_partition_enter(). 47 * It restores the saved registers and jumps to that runtime with 'x0' 48 * as the new SP register. This destroys the C runtime context that had 49 * been built on the stack below the saved context by the caller. Later 50 * the second parameter 'x1' is passed as a return value to the caller. 51 * --------------------------------------------------------------------- 52 */ 53func spm_secure_partition_exit 54 /* Restore the previous stack */ 55 mov sp, x0 56 57 /* Restore callee-saved registers on to the stack */ 58 ldp x19, x20, [x0, #(SP_C_RT_CTX_X19 - SP_C_RT_CTX_SIZE)] 59 ldp x21, x22, [x0, #(SP_C_RT_CTX_X21 - SP_C_RT_CTX_SIZE)] 60 ldp x23, x24, [x0, #(SP_C_RT_CTX_X23 - SP_C_RT_CTX_SIZE)] 61 ldp x25, x26, [x0, #(SP_C_RT_CTX_X25 - SP_C_RT_CTX_SIZE)] 62 ldp x27, x28, [x0, #(SP_C_RT_CTX_X27 - SP_C_RT_CTX_SIZE)] 63 ldp x29, x30, [x0, #(SP_C_RT_CTX_X29 - SP_C_RT_CTX_SIZE)] 64 65 /* --------------------------------------------------------------------- 66 * This should take us back to the instruction after the call to the 67 * last spm_secure_partition_enter().* Place the second parameter to x0 68 * so that the caller will see it as a return value from the original 69 * entry call. 70 * --------------------------------------------------------------------- 71 */ 72 mov x0, x1 73 ret 74endfunc spm_secure_partition_exit 75