/*
 * Copyright (c) 2023 Ian Marco Moffett and the Osmora Team.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of Hyra nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

#include <machine/trap.h>
#include <sys/cdefs.h>
#include <sys/spinlock.h>
#include <sys/syslog.h>
#include <sys/panic.h>

static const char *trap_type[] = {
    [TRAP_BREAKPOINT]   = "breakpoint",
    [TRAP_ARITH_ERR]    = "arithmetic error",
    [TRAP_OVERFLOW]     = "overflow",
    [TRAP_BOUND_RANGE]  = "bound range exceeded",
    [TRAP_INVLOP]       = "invalid opcode",
    [TRAP_DOUBLE_FAULT] = "double fault",
    [TRAP_INVLTSS]      = "invalid TSS",
    [TRAP_SEGNP]        = "segment not present",
    [TRAP_PROTFLT]      = "general protection",
    [TRAP_PAGEFLT]      = "page fault",
    [TRAP_NMI]          = "non-maskable interrupt"
};

static const int TRAP_COUNT = __ARRAY_COUNT(trap_type);
static ftrap_handler_t ftrap_handler = NULL;
static struct spinlock ftrap_handler_lock = { 0 };

static void
trap_print(struct trapframe *tf)
{
    const char *mode;

    if (tf->trapno < TRAP_COUNT) {
        kprintf("** Fatal %s", trap_type[tf->trapno]);
    } else {
        kprintf("** Unknown trap %d", tf->trapno);
    }
    mode = __TEST(tf->trapno, TRAP_USER) ? "user" : "supervisor";
    kprintf(" in %s mode **\n", mode);
}

/*
 * Registers a handler for *fatal* traps.
 */
void
register_ftrap_handler(ftrap_handler_t handler)
{
    spinlock_acquire(&ftrap_handler_lock);
    ftrap_handler = handler;
    spinlock_release(&ftrap_handler_lock);
}

/*
 * Handles traps.
 */
void
trap_handler(struct trapframe *tf)
{
    trap_print(tf);

    /*
     * XXX: Handle NMIs better. For now we just
     *      panic.
     */
    if (tf->trapno == TRAP_NMI) {
        kprintf("Possible hardware failure?\n");
        panic("Caught NMI; bailing out\n");
    }

    panic("Caught pre-sched exception\n");
}