source: mainline/kernel/arch/amd64/src/debugger.c@ 89c57b6

/*
 * 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.
 */

/** @addtogroup amd64debug
 * @{
 */
/** @file
 */

#include <arch/debugger.h>
#include <console/kconsole.h>
#include <console/cmd.h>
#include <print.h>
#include <panic.h>
#include <interrupt.h>
#include <arch/asm.h>
#include <arch/cpu.h>
#include <debug.h>
#include <func.h>
#include <smp/ipi.h>
#include <symtab.h>

#ifdef __64_BITS__
        #define getip(x)  ((x)->rip)
#endif

#ifdef __32_BITS__
        #define getip(x)  ((x)->eip)
#endif

typedef struct  {
        uintptr_t address;   /**< Breakpoint address */
        unsigned int flags;  /**< Flags regarding breakpoint */
        size_t counter;      /**< How many times the exception occured */
} bpinfo_t;

static bpinfo_t breakpoints[BKPOINTS_MAX];
IRQ_SPINLOCK_STATIC_INITIALIZE(bkpoint_lock);

#ifdef CONFIG_KCONSOLE

static int cmd_print_breakpoints(cmd_arg_t *);
static int cmd_del_breakpoint(cmd_arg_t *);
static int cmd_add_breakpoint(cmd_arg_t *);

static cmd_info_t bkpts_info = {
        .name = "bkpts",
        .description = "Print breakpoint table.",
        .func = cmd_print_breakpoints,
        .argc = 0,
};

static cmd_arg_t del_argv = {
        .type = ARG_TYPE_INT
};

static cmd_info_t delbkpt_info = {
        .name = "delbkpt",
        .description = "Delete breakpoint.",
        .func = cmd_del_breakpoint,
        .argc = 1,
        .argv = &del_argv
};

static cmd_arg_t add_argv = {
        .type = ARG_TYPE_INT
};

static cmd_info_t addbkpt_info = {
        .name = "addbkpt",
        .description = "Add 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 = "Add write watchpoint.",
        .func = cmd_add_breakpoint,
        .argc = 1,
        .argv = &addw_argv
};

#endif /* CONFIG_KCONSOLE */

/** Setup DR register according to table
 *
 */
static void setup_dr(int curidx)
{
        ASSERT(curidx >= 0);
        
        bpinfo_t *cur = &breakpoints[curidx];
        unsigned int flags = breakpoints[curidx].flags;
        
        /* Disable breakpoint in DR7 */
        sysarg_t dr7 = read_dr7();
        dr7 &= ~(0x02U << (curidx * 2));
        
        /* Setup DR register */
        if (cur->address) {
                /* 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;
                }
                
                /* Set type to requested breakpoint & length*/
                dr7 &= ~(0x03U << (16 + 4 * curidx));
                dr7 &= ~(0x03U << (18 + 4 * curidx));
                
                if (!(flags & BKPOINT_INSTR)) {
#ifdef __32_BITS__
                        dr7 |= ((sysarg_t) 0x03U) << (18 + 4 * curidx);
#endif
                        
#ifdef __64_BITS__
                        dr7 |= ((sysarg_t) 0x02U) << (18 + 4 * curidx);
#endif
                        
                        if ((flags & BKPOINT_WRITE))
                                dr7 |= ((sysarg_t) 0x01U) << (16 + 4 * curidx);
                        else if ((flags & BKPOINT_READ_WRITE))
                                dr7 |= ((sysarg_t) 0x03U) << (16 + 4 * curidx);
                }
                
                /* Enable global breakpoint */
                dr7 |= 0x02U << (curidx * 2);
                
                write_dr7(dr7);
        }
}

/** 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(const void *where, const unsigned int flags, int curidx)
{
        ASSERT(flags & (BKPOINT_INSTR | BKPOINT_WRITE | BKPOINT_READ_WRITE));
        
        irq_spinlock_lock(&bkpoint_lock, true);
        
        if (curidx == -1) {
                /* Find free space in slots */
                unsigned int i;
                for (i = 0; i < BKPOINTS_MAX; i++) {
                        if (!breakpoints[i].address) {
                                curidx = i;
                                break;
                        }
                }
                
                if (curidx == -1) {
                        /* Too many breakpoints */
                        irq_spinlock_unlock(&bkpoint_lock, true);
                        return -1;
                }
        }
        
        bpinfo_t *cur = &breakpoints[curidx];
        
        cur->address = (uintptr_t) where;
        cur->flags = flags;
        cur->counter = 0;
        
        setup_dr(curidx);
        
        irq_spinlock_unlock(&bkpoint_lock, true);
        
        /* Send IPI */
//      ipi_broadcast(VECTOR_DEBUG_IPI);
        
        return curidx;
}

static void handle_exception(int slot, istate_t *istate)
{
        ASSERT(slot >= 0);
        ASSERT(breakpoints[slot].address);
        
        /* Handle zero checker */
        if (!(breakpoints[slot].flags & BKPOINT_INSTR)) {
                if ((breakpoints[slot].flags & BKPOINT_CHECK_ZERO)) {
                        if (*((sysarg_t *) breakpoints[slot].address) != 0)
                                return;
                        
                        printf("*** Found ZERO on address %p (slot %d) ***\n",
                            (void *) breakpoints[slot].address, slot);
                } else {
                        printf("Data watchpoint - new data: %#" PRIxn "\n",
                            *((sysarg_t *) breakpoints[slot].address));
                }
        }
        
        printf("Reached breakpoint %d:%p (%s)\n", slot,
            (void *) getip(istate), symtab_fmt_name_lookup(getip(istate)));
        
#ifdef CONFIG_KCONSOLE
        atomic_set(&haltstate, 1);
        kconsole("debug", "Debug console ready.\n", false);
        atomic_set(&haltstate, 0);
#endif
}

void breakpoint_del(int slot)
{
        ASSERT(slot >= 0);
        
        irq_spinlock_lock(&bkpoint_lock, true);
        
        bpinfo_t *cur = &breakpoints[slot];
        if (!cur->address) {
                irq_spinlock_unlock(&bkpoint_lock, true);
                return;
        }
        
        cur->address = (uintptr_t) NULL;
        
        setup_dr(slot);
        
        irq_spinlock_unlock(&bkpoint_lock, true);
//      ipi_broadcast(VECTOR_DEBUG_IPI);
}

static void debug_exception(unsigned int n __attribute__((unused)), istate_t *istate)
{
        /* Set RF to restart the instruction  */
#ifdef __64_BITS__
        istate->rflags |= RFLAGS_RF;
#endif
        
#ifdef __32_BITS__
        istate->eflags |= EFLAGS_RF;
#endif
        
        sysarg_t dr6 = read_dr6();
        
        unsigned int i;
        for (i = 0; i < BKPOINTS_MAX; i++) {
                if (dr6 & (1 << i)) {
                        dr6 &= ~ (1 << i);
                        write_dr6(dr6);
                        
                        handle_exception(i, istate);
                }
        }
}

#ifdef CONFIG_SMP
static void debug_ipi(unsigned int n __attribute__((unused)),
    istate_t *istate __attribute__((unused)))
{
        irq_spinlock_lock(&bkpoint_lock, false);
        
        unsigned int i;
        for (i = 0; i < BKPOINTS_MAX; i++)
                setup_dr(i);
        
        irq_spinlock_unlock(&bkpoint_lock, false);
}
#endif /* CONFIG_SMP */

/** Initialize debugger
 *
 */
void debugger_init()
{
        unsigned int i;
        for (i = 0; i < BKPOINTS_MAX; i++)
                breakpoints[i].address = (uintptr_t) NULL;
        
#ifdef CONFIG_KCONSOLE
        cmd_initialize(&bkpts_info);
        if (!cmd_register(&bkpts_info))
                printf("Cannot register command %s\n", bkpts_info.name);
        
        cmd_initialize(&delbkpt_info);
        if (!cmd_register(&delbkpt_info))
                printf("Cannot register command %s\n", delbkpt_info.name);
        
        cmd_initialize(&addbkpt_info);
        if (!cmd_register(&addbkpt_info))
                printf("Cannot register command %s\n", addbkpt_info.name);
        
        cmd_initialize(&addwatchp_info);
        if (!cmd_register(&addwatchp_info))
                printf("Cannot register command %s\n", addwatchp_info.name);
#endif /* CONFIG_KCONSOLE */
        
        exc_register(VECTOR_DEBUG, "debugger", true,
            debug_exception);
        
#ifdef CONFIG_SMP
        exc_register(VECTOR_DEBUG_IPI, "debugger_smp", true,
            debug_ipi);
#endif /* CONFIG_SMP */
}

#ifdef CONFIG_KCONSOLE
/** Print table of active breakpoints
 *
 */
int cmd_print_breakpoints(cmd_arg_t *argv __attribute__((unused)))
{
#ifdef __32_BITS__
        printf("[nr] [count] [address ] [in symbol\n");
#endif
        
#ifdef __64_BITS__
        printf("[nr] [count] [address         ] [in symbol\n");
#endif
        
        unsigned int i;
        for (i = 0; i < BKPOINTS_MAX; i++) {
                if (breakpoints[i].address) {
                        const char *symbol = symtab_fmt_name_lookup(
                            breakpoints[i].address);
                        
#ifdef __32_BITS__
                        printf("%-4u %7zu %p %s\n", i,
                            breakpoints[i].counter, (void *) breakpoints[i].address,
                            symbol);
#endif
                        
#ifdef __64_BITS__
                        printf("%-4u %7zu %p %s\n", i,
                            breakpoints[i].counter, (void *) breakpoints[i].address,
                            symbol);
#endif
                }
        }
        
        return 1;
}

/** Remove breakpoint from table
 *
 */
int cmd_del_breakpoint(cmd_arg_t *argv)
{
        sysarg_t bpno = argv->intval;
        if (bpno > 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)
{
        unsigned int flags;
        if (argv == &add_argv)
                flags = BKPOINT_INSTR;
        else
                flags = BKPOINT_WRITE;
        
        printf("Adding breakpoint on address: %p\n",
            (void *) argv->intval);
        
        int id = breakpoint_add((void *) argv->intval, flags, -1);
        if (id < 0)
                printf("Add breakpoint failed.\n");
        else
                printf("Added breakpoint %d.\n", id);
        
        return 1;
}
#endif /* CONFIG_KCONSOLE */

/** @}
 */