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/*

 * Copyright (c) 2003-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup mips32 

 * @{

 */

/** @file

 */

#include <arch/exception.h>

#include <arch/interrupt.h>

#include <arch/mm/tlb.h>

#include <panic.h>

#include <arch/cp0.h>

#include <arch/types.h>

#include <arch.h>

#include <debug.h>

#include <proc/thread.h>

#include <symtab.h>

#include <print.h>

#include <interrupt.h>

#include <func.h>

#include <ddi/irq.h>

#include <arch/debugger.h>

static char * exctable[] = {

    "Interrupt",

    "TLB Modified",

    "TLB Invalid",

    "TLB Invalid Store",

    "Address Error - load/instr. fetch",

    "Address Error - store",

    "Bus Error - fetch instruction",

    "Bus Error - data reference",

    "Syscall",

    "BreakPoint",

    "Reserved Instruction",

    "Coprocessor Unusable",

    "Arithmetic Overflow",

    "Trap",

    "Virtual Coherency - instruction",

    "Floating Point",

    NULL, NULL, NULL, NULL, NULL, NULL, NULL,

    "WatchHi/WatchLo", /* 23 */

    NULL, NULL, NULL, NULL, NULL, NULL, NULL,

    "Virtual Coherency - data",

};

static void print_regdump(istate_t *istate)

{

    char *pcsymbol = "";

    char *rasymbol = "";

    char *s = get_symtab_entry(istate->epc);

    if (s)

        pcsymbol = s;

    s = get_symtab_entry(istate->ra);

    if (s)

        rasymbol = s;

    printf("PC: %#x(%s) RA: %#x(%s), SP(%p)\n", istate->epc, pcsymbol, istate->ra, rasymbol, istate->sp);

}

static void unhandled_exception(int n, istate_t *istate)

{

    fault_if_from_uspace(istate, "Unhandled exception %s.", exctable[n]);

    print_regdump(istate);

    panic("Unhandled exception %s.", exctable[n]);

}

static void reserved_instr_exception(int n, istate_t *istate)

{

    if (*((uint32_t *)istate->epc) == 0x7c03e83b) {

        ASSERT(THREAD);

        istate->epc += 4;

        istate->v1 = istate->k1;

    } else

        unhandled_exception(n, istate);

}

static void breakpoint_exception(int n, istate_t *istate)

{

#ifdef CONFIG_DEBUG

    debugger_bpoint(istate);

#else

    /* it is necessary to not re-execute BREAK instruction after

       returning from Exception handler

       (see page 138 in R4000 Manual for more information) */

    istate->epc += 4;

#endif

}

static void tlbmod_exception(int n, istate_t *istate)

{

    tlb_modified(istate);

}

static void tlbinv_exception(int n, istate_t *istate)

{

    tlb_invalid(istate);

}

#ifdef CONFIG_FPU_LAZY

static void cpuns_exception(int n, istate_t *istate)

{

    if (cp0_cause_coperr(cp0_cause_read()) == fpu_cop_id)

        scheduler_fpu_lazy_request();

    else {

        fault_if_from_uspace(istate, "Unhandled Coprocessor Unusable Exception.");

        panic("Unhandled Coprocessor Unusable Exception.");

    }

}

#endif

static void interrupt_exception(int n, istate_t *istate)

{

    uint32_t cause;

    int i;

    /* decode interrupt number and process the interrupt */

    cause = (cp0_cause_read() >> 8) & 0xff;

    for (i = 0; i < 8; i++) {

        if (cause & (1 << i)) {

            irq_t *irq = irq_dispatch_and_lock(i);

            if (irq) {

                /*

                 * The IRQ handler was found.

                 */

                irq->handler(irq);

                spinlock_unlock(&irq->lock);

            } else {

                /*

                 * Spurious interrupt.

                 */

#ifdef CONFIG_DEBUG

                printf("cpu%u: spurious interrupt (inum=%d)\n",

                    CPU->id, i);

#endif

            }

        }

    }

}

/** Handle syscall userspace call */

static void syscall_exception(int n, istate_t *istate)

{

    panic("Syscall is handled through shortcut.");

}

void exception_init(void)

{

    int i;

    /* Clear exception table */

    for (i = 0; i < IVT_ITEMS; i++)

        exc_register(i, "undef", (iroutine) unhandled_exception);

    exc_register(EXC_Bp, "bkpoint", (iroutine) breakpoint_exception);

    exc_register(EXC_RI, "resinstr", (iroutine) reserved_instr_exception);

    exc_register(EXC_Mod, "tlb_mod", (iroutine) tlbmod_exception);

    exc_register(EXC_TLBL, "tlbinvl", (iroutine) tlbinv_exception);

    exc_register(EXC_TLBS, "tlbinvl", (iroutine) tlbinv_exception);

    exc_register(EXC_Int, "interrupt", (iroutine) interrupt_exception);

#ifdef CONFIG_FPU_LAZY

    exc_register(EXC_CpU, "cpunus", (iroutine) cpuns_exception);

#endif

    exc_register(EXC_Sys, "syscall", (iroutine) syscall_exception);

}

/** @}

 */