syscall_rvds.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
; */

    AREA |.text|, CODE, READONLY, ALIGN=2
    THUMB
    REQUIRE8
    PRESERVE8

    IMPORT rt_secure_svc_handle

;/*
; * int tzcall(int id, rt_ubase_t arg0, rt_ubase_t arg1, rt_ubase_t arg2);
; */
tzcall PROC
    EXPORT tzcall
	SVC     1                       ;call SVC 1
    BX      LR

    ENDP

tzcall_entry     PROC
    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

    ENDP

syscall_entry     PROC
    BX      LR                      ; return to user app

    ENDP

;/*
; * void SVC_Handler(void);
; */
SVC_Handler    PROC
    EXPORT 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

    ENDP

    ALIGN

    END