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/*

 * Copyright (C) 2006 Ondrej Palkovsky

 * 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.

 */

#include <arch/debugger.h>

#include <console/kconsole.h>

#include <console/cmd.h>

#include <symtab.h>

#include <print.h>

#include <panic.h>

#include <interrupt.h>

#include <arch/asm.h>

#include <arch/cpu.h>

#include <debug.h>

#include <func.h>

typedef struct  {

    __address address;      /**< Breakpoint address */

    int flags;              /**< Flags regarding breakpoint */

    int counter;            /**< How many times the exception occured */

} bpinfo_t;

static bpinfo_t breakpoints[BKPOINTS_MAX];

SPINLOCK_INITIALIZE(bkpoint_lock);

static int cmd_print_breakpoints(cmd_arg_t *argv);

static cmd_info_t bkpts_info = {

    .name = "bkpts",

    .description = "Print breakpoint table.",

    .func = cmd_print_breakpoints,

    .argc = 0,

};

static int cmd_del_breakpoint(cmd_arg_t *argv);

static cmd_arg_t del_argv = {

    .type = ARG_TYPE_INT

};

static cmd_info_t delbkpt_info = {

    .name = "delbkpt",

    .description = "delbkpt <number> - Delete breakpoint.",

    .func = cmd_del_breakpoint,

    .argc = 1,

    .argv = &del_argv

};

static int cmd_add_breakpoint(cmd_arg_t *argv);

static cmd_arg_t add_argv = {

    .type = ARG_TYPE_INT

};

static cmd_info_t addbkpt_info = {

    .name = "addbkpt",

    .description = "addbkpt <&symbol> - new breakpoint.",

    .func = cmd_add_breakpoint,

    .argc = 1,

    .argv = &add_argv

};

static cmd_arg_t addw_argv = {

    .type = ARG_TYPE_INT

};

static cmd_info_t addwatchp_info = {

    .name = "addwatchp",

    .description = "addbwatchp <&symbol> - new write watchpoint.",

    .func = cmd_add_breakpoint,

    .argc = 1,

    .argv = &addw_argv

};

/** Print table of active breakpoints */

int cmd_print_breakpoints(cmd_arg_t *argv)

{

    int i;

    char *symbol;

    printf("Breakpoint table.\n");

    for (i=0; i < BKPOINTS_MAX; i++)

        if (breakpoints[i].address) {

            symbol = get_symtab_entry(breakpoints[i].address);

            printf("%d. 0x%p in %s\n",i,

                   breakpoints[i].address, symbol);

            printf("     Count(%d) ", breakpoints[i].counter);

            printf("\n");

        }

    return 1;

}

/** Enable hardware breakpoint

 *

 *

 * @param where Address of HW breakpoint

 * @param flags Type of breakpoint (EXECUTE, WRITE)

 * @return Debug slot on success, -1 - no available HW breakpoint

 */

int breakpoint_add(void * where, int flags)

{

    bpinfo_t *cur = NULL;

    int curidx;

    ipl_t ipl;

    int i;

    __native dr7;

    ASSERT( flags & (BKPOINT_INSTR | BKPOINT_WRITE | BKPOINT_READ_WRITE));

    ipl = interrupts_disable();

    spinlock_lock(&bkpoint_lock);

    /* Find free space in slots */

    for (i=0; i<BKPOINTS_MAX; i++)

        if (!breakpoints[i].address) {

            cur = &breakpoints[i];

            curidx = i;

            break;

        }

    if (!cur) {

        /* Too many breakpoints */

        spinlock_unlock(&bkpoint_lock);

        interrupts_restore(ipl);

        return -1;

    }

    cur->address = (__address) where;

    cur->flags = flags;

    cur->counter = 0;

    /* Set breakpoint to debug registers */

    switch (curidx) {

    case 0:

        write_dr0(cur->address);

        break;

    case 1:

        write_dr1(cur->address);

        break;

    case 2:

        write_dr2(cur->address);

        break;

    case 3:

        write_dr3(cur->address);

        break;

    }

    dr7 = read_dr7();

    /* Set type to requested breakpoint & length*/

    dr7 &= ~ (0x3 << (16 + 4*curidx));

    dr7 &= ~ (0x3 << (18 + 4*curidx));

    if ((flags & BKPOINT_INSTR)) {

        printf("Instr breakpoint\n");

        ;

    } else {

        if (sizeof(int) == 4)

            dr7 |= 0x3 << (18 + 4*curidx);

        else /* 8 */

            dr7 |= 0x2 << (18 + 4*curidx);

        if ((flags & BKPOINT_WRITE))

            dr7 |= 0x1 << (16 + 4*curidx);

        else if ((flags & BKPOINT_READ_WRITE))

            dr7 |= 0x3 << (16 + 4*curidx);

    }

    /* Enable global breakpoint */

    dr7 |= 0x2 << (curidx*2);

    write_dr7(dr7);

    spinlock_unlock(&bkpoint_lock);

    interrupts_restore(ipl);

    return curidx;

}

static void handle_exception(int slot, istate_t *istate)

{

    ASSERT(breakpoints[slot].address);

    /* Handle zero checker */

    if (! (breakpoints[slot].flags & BKPOINT_INSTR)) {

        if ((breakpoints[slot].flags & BKPOINT_CHECK_ZERO)) {

            if (*((__native *) breakpoints[slot].address) != 0)

                return;

            printf("**** Found ZERO on address %P ****\n",

                   slot, breakpoints[slot].address);

        } else {

            printf("Data watchpoint - new data: %P\n",

                   *((__native *) breakpoints[slot].address));

        }

    }

    printf("Reached breakpoint %d:%P(%s)\n", slot, istate->rip,

           get_symtab_entry(istate->rip));

    printf("***Type 'exit' to exit kconsole.\n");

    atomic_set(&haltstate,1);

    kconsole("debug");

    atomic_set(&haltstate,0);

}

static void debug_exception(int n, istate_t *istate)

{

    __native dr6;

    int i;

    /* Set RF to restart the instruction  */

    istate->rflags |= RFLAGS_RF;

    dr6 = read_dr6();

    for (i=0; i < BKPOINTS_MAX; i++) {

        if (dr6 & (1 << i)) {

            dr6 &= ~ (1 << i);

            write_dr6(dr6);

            handle_exception(i, istate);

        }

    }

}

void breakpoint_del(int slot)

{

    bpinfo_t *cur;

    ipl_t ipl;

    __native dr7;

    ipl = interrupts_disable();

    spinlock_lock(&bkpoint_lock);

    cur = &breakpoints[slot];

    if (!cur->address) {

        spinlock_unlock(&bkpoint_lock);

        interrupts_restore(ipl);

        return;

    }

    cur->address = NULL;

    /* Disable breakpoint in DR7 */

    dr7 = read_dr7();

    dr7 &= ~(0x2 << (slot*2));

    write_dr7(dr7);

    spinlock_unlock(&bkpoint_lock);

    interrupts_restore(ipl);

}

/** Remove breakpoint from table */

int cmd_del_breakpoint(cmd_arg_t *argv)

{

    if (argv->intval < 0 || argv->intval > BKPOINTS_MAX) {

        printf("Invalid breakpoint number.\n");

        return 0;

    }

    breakpoint_del(argv->intval);

    return 1;

}

/** Add new breakpoint to table */

static int cmd_add_breakpoint(cmd_arg_t *argv)

{

    int flags;

    if (argv == &add_argv) {

        flags = BKPOINT_INSTR;

    } else { /* addwatchp */

        flags = BKPOINT_WRITE;

    }

    printf("Adding breakpoint on address: %p\n", argv->intval);

    if (breakpoint_add((void *)argv->intval, flags))

        printf("Add breakpoint failed.\n");

    return 1;

}

/** Initialize debugger */

void debugger_init()

{

    int i;

    for (i=0; i<BKPOINTS_MAX; i++)

        breakpoints[i].address = NULL;

    cmd_initialize(&bkpts_info);

    if (!cmd_register(&bkpts_info))

        panic("could not register command %s\n", bkpts_info.name);

    cmd_initialize(&delbkpt_info);

    if (!cmd_register(&delbkpt_info))

        panic("could not register command %s\n", delbkpt_info.name);

    cmd_initialize(&addbkpt_info);

    if (!cmd_register(&addbkpt_info))

        panic("could not register command %s\n", addbkpt_info.name);

    cmd_initialize(&addwatchp_info);

    if (!cmd_register(&addwatchp_info))

        panic("could not register command %s\n", addwatchp_info.name);

    exc_register(VECTOR_DEBUG, "debugger",

             debug_exception);

}