syscall_gcc.S

/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2019-10-25     tyx          first version
 */

.cpu cortex-m4
.syntax unified
.thumb
.text

/*
 * int tzcall(int id, rt_ubase_t arg0, rt_ubase_t arg1, rt_ubase_t arg2);
 */
.global tzcall
.type tzcall, %function
tzcall:
	SVC     1                       /* call SVC 1 */
    BX      LR

tzcall_entry:
    PUSH    {R1, R4, LR}
    MOV     R4, R1                  /* copy thread SP to R4 */
    LDMFD   R4!, {r0 - r3}          /* pop user stack, get input arg0, arg1, arg2 */
    STMFD   R4!, {r0 - r3}          /* push stack, user stack recovery */
    BL      rt_secure_svc_handle    /* call fun */
    POP     {R1, R4, LR}
    STR     R0, [R1]                /* update return value */
    BX      LR                      /* return to thread */

syscall_entry:
    BX      LR                      /* return to user app */

.global SVC_Handler
.type SVC_Handler, %function
SVC_Handler:

    /* get SP, save to R1 */
    MRS     R1, MSP                 /* get fault context from handler. */
    TST     LR, #0x04               /* if(!EXC_RETURN[2]) */
    BEQ     get_sp_done
    MRS     R1, PSP                 /* get fault context from thread. */
get_sp_done:

    /* get svc index */
    LDR     R0, [R1, #24]
    LDRB    R0, [R0, #-2]

    /* if svc == 0, do system call */
    CMP     R0, #0x0
    BEQ    syscall_entry

    /* if svc == 1, do TrustZone call */
    CMP     R0, #0x1
    BEQ    tzcall_entry