/*
 * Copyright 2021, Haiku, Inc.
 * Distributed under the terms of the MIT License.
 */


#include <asm_defs.h>
#include "arch_traps.h"
#include "asm_offsets.h"


.align 4
FUNCTION(SVec):
        PushTrapFrame IFRAME_ra
        sd fp, IFRAME_sp(sp)
        csrr t0, sepc
        sd   t0, IFRAME_epc(sp)

        csrr t0, sstatus
        sd   t0, IFRAME_status(sp)
        csrr t0, scause
        sd   t0, IFRAME_cause(sp)
        csrr t0, stval
        sd   t0, IFRAME_tval(sp)

        mv a0, sp
        call STrap

FUNCTION(SVecRet):
        ld   t0, IFRAME_status(sp)
        csrw sstatus, t0

        ld t0, IFRAME_epc(sp)
        csrw sepc, t0
        PopTrapFrame IFRAME_ra
        sret
FUNCTION_END(SVec)


.align 4
FUNCTION(SVecU):
        # switch to kernel stack, SSCRATCH will hold user SP
        csrrw sp, sscratch, sp

        PushTrapFrame IFRAME_ra
        csrr t0, sscratch
        sd   t0, IFRAME_sp(sp)
        csrr t0, sepc
        sd   t0, IFRAME_epc(sp)

        csrr t0, sstatus
        sd   t0, IFRAME_status(sp)
        csrr t0, scause
        sd   t0, IFRAME_cause(sp)
        csrr t0, stval
        sd   t0, IFRAME_tval(sp)

        ld tp, ARCH_STACK_thread(fp)

        la   t0,    SVec
        csrw stvec, t0

        mv a0, sp
        call STrap

FUNCTION(SVecURet):
        ld   t0, IFRAME_status(sp)
        csrw sstatus, t0

        csrw sscratch, fp # save kernel SP

        la   t0,    SVecU
        csrw stvec, t0

        ld tp, IFRAME_tp(sp)
        ld t0, IFRAME_epc(sp)
        csrw sepc, t0
        PopTrapFrame IFRAME_ra
        sret
FUNCTION_END(SVecU)