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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 <print.h>
#include <interrupt.h>
#include <func.h>
#include <ddi/irq.h>
#include <arch/debugger.h>
#include <symtab.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, *rasymbol;

    pcsymbol = symtab_fmt_name_lookup(istate->epc);
    rasymbol = symtab_fmt_name_lookup(istate->ra);

    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);
}

/** @}
 */