source: mainline/kernel/arch/mips32/src/debugger.c@ d776329b

/*
 * Copyright (c) 2005 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 mips32debug
 * @{
 */
/** @file
 */

#include <arch/debugger.h>
#include <arch/barrier.h>
#include <memstr.h>
#include <console/kconsole.h>
#include <console/cmd.h>
#include <print.h>
#include <log.h>
#include <panic.h>
#include <arch.h>
#include <arch/cp0.h>
#include <func.h>
#include <symtab.h>

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 bkpoint (break on j/branch insts unsupported).",
        .func = cmd_add_breakpoint,
        .argc = 1,
        .argv = &add_argv
};

static cmd_arg_t adde_argv[] = {
        { .type = ARG_TYPE_INT },
        { .type = ARG_TYPE_INT }
};
static cmd_info_t addbkpte_info = {
        .name = "addbkpte",
        .description = "Add bkpoint with a trigger function.",
        .func = cmd_add_breakpoint,
        .argc = 2,
        .argv = adde_argv
};
#endif

static struct {
        uint32_t andmask;
        uint32_t value;
} jmpinstr[] = {
        {0xf3ff0000, 0x41000000},  /* BCzF */
        {0xf3ff0000, 0x41020000},  /* BCzFL */
        {0xf3ff0000, 0x41010000},  /* BCzT */
        {0xf3ff0000, 0x41030000},  /* BCzTL */
        {0xfc000000, 0x10000000},  /* BEQ */
        {0xfc000000, 0x50000000},  /* BEQL */
        {0xfc1f0000, 0x04010000},  /* BEQL */
        {0xfc1f0000, 0x04110000},  /* BGEZAL */
        {0xfc1f0000, 0x04130000},  /* BGEZALL */
        {0xfc1f0000, 0x04030000},  /* BGEZL */
        {0xfc1f0000, 0x1c000000},  /* BGTZ */
        {0xfc1f0000, 0x5c000000},  /* BGTZL */
        {0xfc1f0000, 0x18000000},  /* BLEZ */
        {0xfc1f0000, 0x58000000},  /* BLEZL */
        {0xfc1f0000, 0x04000000},  /* BLTZ */
        {0xfc1f0000, 0x04100000},  /* BLTZAL */
        {0xfc1f0000, 0x04120000},  /* BLTZALL */
        {0xfc1f0000, 0x04020000},  /* BLTZL */
        {0xfc000000, 0x14000000},  /* BNE */
        {0xfc000000, 0x54000000},  /* BNEL */
        {0xfc000000, 0x08000000},  /* J */
        {0xfc000000, 0x0c000000},  /* JAL */
        {0xfc1f07ff, 0x00000009},  /* JALR */
        {0, 0}                     /* end of table */
};

/** Test, if the given instruction is a jump or branch instruction
 *
 * @param instr Instruction code
 *
 * @return true if it is jump instruction, false otherwise
 *
 */
bool is_jump(sysarg_t instr)
{
        unsigned int i;
        
        for (i = 0; jmpinstr[i].andmask; i++) {
                if ((instr & jmpinstr[i].andmask) == jmpinstr[i].value)
                        return true;
        }
        
        return false;
}

#ifdef CONFIG_KCONSOLE

/** Add new breakpoint to table
 *
 */
int cmd_add_breakpoint(cmd_arg_t *argv)
{
        if (argv->intval & 0x3) {
                printf("Not aligned instruction, forgot to use &symbol?\n");
                return 1;
        }
        
        irq_spinlock_lock(&bkpoint_lock, true);
        
        /* Check, that the breakpoints do not conflict */
        unsigned int i;
        for (i = 0; i < BKPOINTS_MAX; i++) {
                if (breakpoints[i].address == (uintptr_t) argv->intval) {
                        printf("Duplicate breakpoint %d.\n", i);
                        irq_spinlock_unlock(&bkpoint_lock, true);
                        return 0;
                } else if ((breakpoints[i].address == (uintptr_t) argv->intval +
                    sizeof(sysarg_t)) || (breakpoints[i].address ==
                    (uintptr_t) argv->intval - sizeof(sysarg_t))) {
                        printf("Adjacent breakpoints not supported, conflict "
                            "with %d.\n", i);
                        irq_spinlock_unlock(&bkpoint_lock, true);
                        return 0;
                }
                
        }
        
        bpinfo_t *cur = NULL;
        
        for (i = 0; i < BKPOINTS_MAX; i++) {
                if (!breakpoints[i].address) {
                        cur = &breakpoints[i];
                        break;
                }
        }
        
        if (!cur) {
                printf("Too many breakpoints.\n");
                irq_spinlock_unlock(&bkpoint_lock, true);
                return 0;
        }
        
        printf("Adding breakpoint on address %p\n", (void *) argv->intval);
        
        cur->address = (uintptr_t) argv->intval;
        cur->instruction = ((sysarg_t *) cur->address)[0];
        cur->nextinstruction = ((sysarg_t *) cur->address)[1];
        if (argv == &add_argv) {
                cur->flags = 0;
        } else {  /* We are add extended */
                cur->flags = BKPOINT_FUNCCALL;
                cur->bkfunc = (void (*)(void *, istate_t *)) argv[1].intval;
        }
        
        if (is_jump(cur->instruction))
                cur->flags |= BKPOINT_ONESHOT;
        
        cur->counter = 0;
        
        /* Set breakpoint */
        *((sysarg_t *) cur->address) = 0x0d;
        smc_coherence(cur->address);
        
        irq_spinlock_unlock(&bkpoint_lock, true);
        
        return 1;
}

/** Remove breakpoint from table
 *
 */
int cmd_del_breakpoint(cmd_arg_t *argv)
{
        if (argv->intval > BKPOINTS_MAX) {
                printf("Invalid breakpoint number.\n");
                return 0;
        }
        
        irq_spinlock_lock(&bkpoint_lock, true);
        
        bpinfo_t *cur = &breakpoints[argv->intval];
        if (!cur->address) {
                printf("Breakpoint does not exist.\n");
                irq_spinlock_unlock(&bkpoint_lock, true);
                return 0;
        }
        
        if ((cur->flags & BKPOINT_INPROG) && (cur->flags & BKPOINT_ONESHOT)) {
                printf("Cannot remove one-shot breakpoint in-progress\n");
                irq_spinlock_unlock(&bkpoint_lock, true);
                return 0;
        }
        
        ((uint32_t *) cur->address)[0] = cur->instruction;
        smc_coherence(((uint32_t *) cur->address)[0]);
        ((uint32_t *) cur->address)[1] = cur->nextinstruction;
        smc_coherence(((uint32_t *) cur->address)[1]);
        
        cur->address = (uintptr_t) NULL;
        
        irq_spinlock_unlock(&bkpoint_lock, true);
        return 1;
}

/** Print table of active breakpoints
 *
 */
int cmd_print_breakpoints(cmd_arg_t *argv)
{
        unsigned int i;
        
        printf("[nr] [count] [address ] [inprog] [oneshot] [funccall] [in symbol\n");
        
        for (i = 0; i < BKPOINTS_MAX; i++) {
                if (breakpoints[i].address) {
                        const char *symbol = symtab_fmt_name_lookup(
                            breakpoints[i].address);
                        
                        printf("%-4u %7zu %p %-8s %-9s %-10s %s\n", i,
                            breakpoints[i].counter, (void *) breakpoints[i].address,
                            ((breakpoints[i].flags & BKPOINT_INPROG) ? "true" :
                            "false"), ((breakpoints[i].flags & BKPOINT_ONESHOT)
                            ? "true" : "false"), ((breakpoints[i].flags &
                            BKPOINT_FUNCCALL) ? "true" : "false"), symbol);
                }
        }
        
        return 1;
}

#endif /* CONFIG_KCONSOLE */

/** Initialize debugger
 *
 */
void debugger_init(void)
{
        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))
                log(LF_OTHER, LVL_WARN, "Cannot register command %s",
                    bkpts_info.name);
        
        cmd_initialize(&delbkpt_info);
        if (!cmd_register(&delbkpt_info))
                log(LF_OTHER, LVL_WARN, "Cannot register command %s",
                    delbkpt_info.name);
        
        cmd_initialize(&addbkpt_info);
        if (!cmd_register(&addbkpt_info))
                log(LF_OTHER, LVL_WARN, "Cannot register command %s",
                    addbkpt_info.name);
        
        cmd_initialize(&addbkpte_info);
        if (!cmd_register(&addbkpte_info))
                log(LF_OTHER, LVL_WARN, "Cannot register command %s",
                    addbkpte_info.name);
#endif /* CONFIG_KCONSOLE */
}

/** Handle breakpoint
 *
 * Find breakpoint in breakpoint table.
 * If found, call kconsole, set break on next instruction and reexecute.
 * If we are on "next instruction", set it back on the first and reexecute.
 * If breakpoint not found in breakpoint table, call kconsole and start
 * next instruction.
 *
 */
void debugger_bpoint(istate_t *istate)
{
        /* test branch delay slot */
        if (cp0_cause_read() & 0x80000000)
                panic("Breakpoint in branch delay slot not supported.");
        
        irq_spinlock_lock(&bkpoint_lock, false);
        
        bpinfo_t *cur = NULL;
        uintptr_t fireaddr = istate->epc;
        unsigned int i;
        
        for (i = 0; i < BKPOINTS_MAX; i++) {
                /* Normal breakpoint */
                if ((fireaddr == breakpoints[i].address) &&
                    (!(breakpoints[i].flags & BKPOINT_REINST))) {
                        cur = &breakpoints[i];
                        break;
                }
                
                /* Reinst only breakpoint */
                if ((breakpoints[i].flags & BKPOINT_REINST) &&
                    (fireaddr == breakpoints[i].address + sizeof(sysarg_t))) {
                        cur = &breakpoints[i];
                        break;
                }
        }
        
        if (cur) {
                if (cur->flags & BKPOINT_REINST) {
                        /* Set breakpoint on first instruction */
                        ((uint32_t *) cur->address)[0] = 0x0d;
                        smc_coherence(((uint32_t *)cur->address)[0]);
                        
                        /* Return back the second */
                        ((uint32_t *) cur->address)[1] = cur->nextinstruction;
                        smc_coherence(((uint32_t *) cur->address)[1]);
                        
                        cur->flags &= ~BKPOINT_REINST;
                        irq_spinlock_unlock(&bkpoint_lock, false);
                        return;
                }
                
                if (cur->flags & BKPOINT_INPROG)
                        printf("Warning: breakpoint recursion\n");
                
                if (!(cur->flags & BKPOINT_FUNCCALL)) {
                        printf("***Breakpoint %u: %p in %s.\n", i,
                            (void *) fireaddr,
                            symtab_fmt_name_lookup(fireaddr));
                }
                
                /* Return first instruction back */
                ((uint32_t *)cur->address)[0] = cur->instruction;
                smc_coherence(cur->address);

                if (! (cur->flags & BKPOINT_ONESHOT)) {
                        /* Set Breakpoint on next instruction */
                        ((uint32_t *)cur->address)[1] = 0x0d;
                        cur->flags |= BKPOINT_REINST;
                } 
                cur->flags |= BKPOINT_INPROG;
        } else {
                printf("***Breakpoint %d: %p in %s.\n", i,
                    (void *) fireaddr,
                    symtab_fmt_name_lookup(fireaddr));
                
                /* Move on to next instruction */
                istate->epc += 4;
        }
        
        if (cur)
                cur->counter++;
        
        if (cur && (cur->flags & BKPOINT_FUNCCALL)) {
                /* Allow zero bkfunc, just for counting */
                if (cur->bkfunc)
                        cur->bkfunc(cur, istate);
        } else {
#ifdef CONFIG_KCONSOLE
                /*
                 * This disables all other processors - we are not SMP,
                 * actually this gets us to cpu_halt, if scheduler() is run
                 * - we generally do not want scheduler to be run from debug,
                 *   so this is a good idea
                 */
                atomic_set(&haltstate, 1);
                irq_spinlock_unlock(&bkpoint_lock, false);
                
                kconsole("debug", "Debug console ready.\n", false);
                
                irq_spinlock_lock(&bkpoint_lock, false);
                atomic_set(&haltstate, 0);
#endif
        }
        
        if ((cur) && (cur->address == fireaddr)
            && ((cur->flags & BKPOINT_INPROG))) {
                /* Remove one-shot breakpoint */
                if ((cur->flags & BKPOINT_ONESHOT))
                        cur->address = (uintptr_t) NULL;
                
                /* Remove in-progress flag */
                cur->flags &= ~BKPOINT_INPROG;
        }
        
        irq_spinlock_unlock(&bkpoint_lock, false);
}

/** @}
 */