1*b61d94a1SMarc Bonnici/* 2*b61d94a1SMarc Bonnici * Copyright (c) 2017-2022, ARM Limited and Contributors. All rights reserved. 3*b61d94a1SMarc Bonnici * 4*b61d94a1SMarc Bonnici * SPDX-License-Identifier: BSD-3-Clause 5*b61d94a1SMarc Bonnici */ 6*b61d94a1SMarc Bonnici 7*b61d94a1SMarc Bonnici#include <asm_macros.S> 8*b61d94a1SMarc Bonnici#include "spm_common.h" 9*b61d94a1SMarc Bonnici 10*b61d94a1SMarc Bonnici .global spm_secure_partition_enter 11*b61d94a1SMarc Bonnici .global spm_secure_partition_exit 12*b61d94a1SMarc Bonnici 13*b61d94a1SMarc Bonnici /* --------------------------------------------------------------------- 14*b61d94a1SMarc Bonnici * This function is called with SP_EL0 as stack. Here we stash our EL3 15*b61d94a1SMarc Bonnici * callee-saved registers on to the stack as a part of saving the C 16*b61d94a1SMarc Bonnici * runtime and enter the secure payload. 17*b61d94a1SMarc Bonnici * 'x0' contains a pointer to the memory where the address of the C 18*b61d94a1SMarc Bonnici * runtime context is to be saved. 19*b61d94a1SMarc Bonnici * --------------------------------------------------------------------- 20*b61d94a1SMarc Bonnici */ 21*b61d94a1SMarc Bonnicifunc spm_secure_partition_enter 22*b61d94a1SMarc Bonnici /* Make space for the registers that we're going to save */ 23*b61d94a1SMarc Bonnici mov x3, sp 24*b61d94a1SMarc Bonnici str x3, [x0, #0] 25*b61d94a1SMarc Bonnici sub sp, sp, #SP_C_RT_CTX_SIZE 26*b61d94a1SMarc Bonnici 27*b61d94a1SMarc Bonnici /* Save callee-saved registers on to the stack */ 28*b61d94a1SMarc Bonnici stp x19, x20, [sp, #SP_C_RT_CTX_X19] 29*b61d94a1SMarc Bonnici stp x21, x22, [sp, #SP_C_RT_CTX_X21] 30*b61d94a1SMarc Bonnici stp x23, x24, [sp, #SP_C_RT_CTX_X23] 31*b61d94a1SMarc Bonnici stp x25, x26, [sp, #SP_C_RT_CTX_X25] 32*b61d94a1SMarc Bonnici stp x27, x28, [sp, #SP_C_RT_CTX_X27] 33*b61d94a1SMarc Bonnici stp x29, x30, [sp, #SP_C_RT_CTX_X29] 34*b61d94a1SMarc Bonnici 35*b61d94a1SMarc Bonnici /* --------------------------------------------------------------------- 36*b61d94a1SMarc Bonnici * Everything is setup now. el3_exit() will use the secure context to 37*b61d94a1SMarc Bonnici * restore to the general purpose and EL3 system registers to ERET 38*b61d94a1SMarc Bonnici * into the secure payload. 39*b61d94a1SMarc Bonnici * --------------------------------------------------------------------- 40*b61d94a1SMarc Bonnici */ 41*b61d94a1SMarc Bonnici b el3_exit 42*b61d94a1SMarc Bonniciendfunc spm_secure_partition_enter 43*b61d94a1SMarc Bonnici 44*b61d94a1SMarc Bonnici /* --------------------------------------------------------------------- 45*b61d94a1SMarc Bonnici * This function is called with 'x0' pointing to a C runtime context 46*b61d94a1SMarc Bonnici * saved in spm_secure_partition_enter(). 47*b61d94a1SMarc Bonnici * It restores the saved registers and jumps to that runtime with 'x0' 48*b61d94a1SMarc Bonnici * as the new SP register. This destroys the C runtime context that had 49*b61d94a1SMarc Bonnici * been built on the stack below the saved context by the caller. Later 50*b61d94a1SMarc Bonnici * the second parameter 'x1' is passed as a return value to the caller. 51*b61d94a1SMarc Bonnici * --------------------------------------------------------------------- 52*b61d94a1SMarc Bonnici */ 53*b61d94a1SMarc Bonnicifunc spm_secure_partition_exit 54*b61d94a1SMarc Bonnici /* Restore the previous stack */ 55*b61d94a1SMarc Bonnici mov sp, x0 56*b61d94a1SMarc Bonnici 57*b61d94a1SMarc Bonnici /* Restore callee-saved registers on to the stack */ 58*b61d94a1SMarc Bonnici ldp x19, x20, [x0, #(SP_C_RT_CTX_X19 - SP_C_RT_CTX_SIZE)] 59*b61d94a1SMarc Bonnici ldp x21, x22, [x0, #(SP_C_RT_CTX_X21 - SP_C_RT_CTX_SIZE)] 60*b61d94a1SMarc Bonnici ldp x23, x24, [x0, #(SP_C_RT_CTX_X23 - SP_C_RT_CTX_SIZE)] 61*b61d94a1SMarc Bonnici ldp x25, x26, [x0, #(SP_C_RT_CTX_X25 - SP_C_RT_CTX_SIZE)] 62*b61d94a1SMarc Bonnici ldp x27, x28, [x0, #(SP_C_RT_CTX_X27 - SP_C_RT_CTX_SIZE)] 63*b61d94a1SMarc Bonnici ldp x29, x30, [x0, #(SP_C_RT_CTX_X29 - SP_C_RT_CTX_SIZE)] 64*b61d94a1SMarc Bonnici 65*b61d94a1SMarc Bonnici /* --------------------------------------------------------------------- 66*b61d94a1SMarc Bonnici * This should take us back to the instruction after the call to the 67*b61d94a1SMarc Bonnici * last spm_secure_partition_enter().* Place the second parameter to x0 68*b61d94a1SMarc Bonnici * so that the caller will see it as a return value from the original 69*b61d94a1SMarc Bonnici * entry call. 70*b61d94a1SMarc Bonnici * --------------------------------------------------------------------- 71*b61d94a1SMarc Bonnici */ 72*b61d94a1SMarc Bonnici mov x0, x1 73*b61d94a1SMarc Bonnici ret 74*b61d94a1SMarc Bonniciendfunc spm_secure_partition_exit 75