NetBSD/sys/ddb/db_run.c

460 lines
11 KiB
C

/* $NetBSD: db_run.c,v 1.30 2007/02/22 06:41:01 thorpej Exp $ */
/*
* Mach Operating System
* Copyright (c) 1993-1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
/*
* Commands to run process.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_run.c,v 1.30 2007/02/22 06:41:01 thorpej Exp $");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <machine/db_machdep.h>
#include <ddb/db_run.h>
#include <ddb/db_access.h>
#include <ddb/db_break.h>
int db_inst_count;
int db_load_count;
int db_store_count;
#ifdef SOFTWARE_SSTEP
static void db_set_temp_breakpoint(db_breakpoint_t, db_addr_t);
static void db_delete_temp_breakpoint(db_breakpoint_t);
static struct db_breakpoint db_not_taken_bkpt;
static struct db_breakpoint db_taken_bkpt;
#endif
#if defined(DDB)
#include <ddb/db_lex.h>
#include <ddb/db_watch.h>
#include <ddb/db_output.h>
#include <ddb/db_sym.h>
#include <ddb/db_extern.h>
static int db_run_mode;
#define STEP_NONE 0
#define STEP_ONCE 1
#define STEP_RETURN 2
#define STEP_CALLT 3
#define STEP_CONTINUE 4
#define STEP_INVISIBLE 5
#define STEP_COUNT 6
static bool db_sstep_print;
static int db_loop_count;
static int db_call_depth;
bool
db_stop_at_pc(db_regs_t *regs, bool *is_breakpoint)
{
db_addr_t pc;
db_breakpoint_t bkpt;
pc = PC_REGS(regs);
#ifdef FIXUP_PC_AFTER_BREAK
if (*is_breakpoint) {
/*
* Breakpoint trap. Regardless if we treat this as a
* real breakpoint (e.g. software single-step), fix up the PC.
*/
FIXUP_PC_AFTER_BREAK(regs);
pc = PC_REGS(regs);
}
#endif
#ifdef SOFTWARE_SSTEP
/*
* If we stopped at one of the single-step breakpoints, say it's not
* really a breakpoint so that we don't skip over the real instruction.
*/
if (db_taken_bkpt.address == pc || db_not_taken_bkpt.address == pc)
*is_breakpoint = false;
#endif /* SOFTWARE_SSTEP */
db_clear_single_step(regs);
db_clear_breakpoints();
db_clear_watchpoints();
/*
* Now check for a breakpoint at this address.
*/
bkpt = db_find_breakpoint_here(pc);
if (bkpt) {
if (--bkpt->count == 0) {
bkpt->count = bkpt->init_count;
*is_breakpoint = true;
return (true); /* stop here */
}
} else if (*is_breakpoint) {
#ifdef PC_ADVANCE
PC_ADVANCE(regs);
#else
PC_REGS(regs) += BKPT_SIZE;
#endif
}
*is_breakpoint = false;
if (db_run_mode == STEP_INVISIBLE) {
db_run_mode = STEP_CONTINUE;
return (false); /* continue */
}
if (db_run_mode == STEP_COUNT) {
return (false); /* continue */
}
if (db_run_mode == STEP_ONCE) {
if (--db_loop_count > 0) {
if (db_sstep_print) {
db_printf("\t\t");
db_print_loc_and_inst(pc);
db_printf("\n");
}
return (false); /* continue */
}
}
if (db_run_mode == STEP_RETURN) {
db_expr_t ins = db_get_value(pc, sizeof(int), false);
/* continue until matching return */
if (!inst_trap_return(ins) &&
(!inst_return(ins) || --db_call_depth != 0)) {
if (db_sstep_print) {
if (inst_call(ins) || inst_return(ins)) {
int i;
db_printf("[after %6d] ",
db_inst_count);
for (i = db_call_depth; --i > 0; )
db_printf(" ");
db_print_loc_and_inst(pc);
db_printf("\n");
}
}
if (inst_call(ins))
db_call_depth++;
return (false); /* continue */
}
}
if (db_run_mode == STEP_CALLT) {
db_expr_t ins = db_get_value(pc, sizeof(int), false);
/* continue until call or return */
if (!inst_call(ins) &&
!inst_return(ins) &&
!inst_trap_return(ins)) {
return (false); /* continue */
}
}
db_run_mode = STEP_NONE;
return (true);
}
void
db_restart_at_pc(db_regs_t *regs, bool watchpt)
{
db_addr_t pc = PC_REGS(regs);
#ifdef SOFTWARE_SSTEP
db_addr_t brpc;
#endif
if ((db_run_mode == STEP_COUNT) ||
(db_run_mode == STEP_RETURN) ||
(db_run_mode == STEP_CALLT)) {
db_expr_t ins;
/*
* We are about to execute this instruction,
* so count it now.
*/
ins = db_get_value(pc, sizeof(int), false);
db_inst_count++;
db_load_count += inst_load(ins);
db_store_count += inst_store(ins);
#ifdef SOFTWARE_SSTEP
/*
* Account for instructions in delay slots.
*/
brpc = next_instr_address(pc, true);
if ((brpc != pc) &&
(inst_branch(ins) || inst_call(ins) || inst_return(ins))) {
ins = db_get_value(brpc, sizeof(int), false);
db_inst_count++;
db_load_count += inst_load(ins);
db_store_count += inst_store(ins);
}
#endif
}
if (db_run_mode == STEP_CONTINUE) {
if (watchpt || db_find_breakpoint_here(pc)) {
/*
* Step over breakpoint/watchpoint.
*/
db_run_mode = STEP_INVISIBLE;
db_set_single_step(regs);
} else {
db_set_breakpoints();
db_set_watchpoints();
}
} else {
db_set_single_step(regs);
}
}
void
db_single_step(db_regs_t *regs)
{
if (db_run_mode == STEP_CONTINUE) {
db_run_mode = STEP_INVISIBLE;
db_set_single_step(regs);
}
}
/* single-step */
/*ARGSUSED*/
void
db_single_step_cmd(db_expr_t addr, bool have_addr,
db_expr_t count, const char *modif)
{
bool print = false;
if (count == -1)
count = 1;
if (modif[0] == 'p')
print = true;
db_run_mode = STEP_ONCE;
db_loop_count = count;
db_sstep_print = print;
db_inst_count = 0;
db_load_count = 0;
db_store_count = 0;
db_cmd_loop_done = 1;
}
/* trace and print until call/return */
/*ARGSUSED*/
void
db_trace_until_call_cmd(db_expr_t addr, bool have_addr,
db_expr_t count, const char *modif)
{
bool print = false;
if (modif[0] == 'p')
print = true;
db_run_mode = STEP_CALLT;
db_sstep_print = print;
db_inst_count = 0;
db_load_count = 0;
db_store_count = 0;
db_cmd_loop_done = 1;
}
/*ARGSUSED*/
void
db_trace_until_matching_cmd(db_expr_t addr, bool have_addr,
db_expr_t count, const char *modif)
{
bool print = false;
if (modif[0] == 'p')
print = true;
db_run_mode = STEP_RETURN;
db_call_depth = 1;
db_sstep_print = print;
db_inst_count = 0;
db_load_count = 0;
db_store_count = 0;
db_cmd_loop_done = 1;
}
/* continue */
/*ARGSUSED*/
void
db_continue_cmd(db_expr_t addr, bool have_addr,
db_expr_t count, const char *modif)
{
if (modif[0] == 'c')
db_run_mode = STEP_COUNT;
else
db_run_mode = STEP_CONTINUE;
db_inst_count = 0;
db_load_count = 0;
db_store_count = 0;
db_cmd_loop_done = 1;
}
#endif /* DDB */
#ifdef SOFTWARE_SSTEP
/*
* Software implementation of single-stepping.
* If your machine does not have a trace mode
* similar to the vax or sun ones you can use
* this implementation, done for the mips.
* Just define the above conditional and provide
* the functions/macros defined below.
*
* bool inst_branch(int inst)
* bool inst_call(int inst)
* returns true if the instruction might branch
*
* bool inst_unconditional_flow_transfer(int inst)
* returns true if the instruction is an unconditional
* transter of flow (i.e. unconditional branch)
*
* db_addr_t branch_taken(int inst, db_addr_t pc, db_regs_t *regs)
* returns the target address of the branch
*
* db_addr_t next_instr_address(db_addr_t pc, bool bd)
* returns the address of the first instruction following the
* one at "pc", which is either in the taken path of the branch
* (bd == true) or not. This is for machines (e.g. mips) with
* branch delays.
*
* A single-step may involve at most 2 breakpoints -
* one for branch-not-taken and one for branch taken.
* If one of these addresses does not already have a breakpoint,
* we allocate a breakpoint and save it here.
* These breakpoints are deleted on return.
*/
#if !defined(DDB)
/* XXX - don't check for existing breakpoints in KGDB-only case */
#define db_find_breakpoint_here(pc) (0)
#endif
void
db_set_single_step(db_regs_t *regs)
{
db_addr_t pc = PC_REGS(regs), brpc = pc;
bool unconditional;
unsigned int inst;
/*
* User was stopped at pc, e.g. the instruction
* at pc was not executed.
*/
inst = db_get_value(pc, sizeof(int), false);
if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) {
brpc = branch_taken(inst, pc, regs);
if (brpc != pc) { /* self-branches are hopeless */
db_set_temp_breakpoint(&db_taken_bkpt, brpc);
} else
db_taken_bkpt.address = 0;
pc = next_instr_address(pc, true);
}
/*
* Check if this control flow instruction is an
* unconditional transfer.
*/
unconditional = inst_unconditional_flow_transfer(inst);
pc = next_instr_address(pc, false);
/*
* We only set the sequential breakpoint if previous
* instruction was not an unconditional change of flow
* control. If the previous instruction is an
* unconditional change of flow control, setting a
* breakpoint in the next sequential location may set
* a breakpoint in data or in another routine, which
* could screw up in either the program or the debugger.
* (Consider, for instance, that the next sequential
* instruction is the start of a routine needed by the
* debugger.)
*
* Also, don't set both the taken and not-taken breakpoints
* in the same place even if the MD code would otherwise
* have us do so.
*/
if (unconditional == false &&
db_find_breakpoint_here(pc) == 0 &&
pc != brpc)
db_set_temp_breakpoint(&db_not_taken_bkpt, pc);
else
db_not_taken_bkpt.address = 0;
}
void
db_clear_single_step(db_regs_t *regs)
{
if (db_taken_bkpt.address != 0)
db_delete_temp_breakpoint(&db_taken_bkpt);
if (db_not_taken_bkpt.address != 0)
db_delete_temp_breakpoint(&db_not_taken_bkpt);
}
void
db_set_temp_breakpoint(db_breakpoint_t bkpt, db_addr_t addr)
{
bkpt->map = NULL;
bkpt->address = addr;
/* bkpt->flags = BKPT_TEMP; - this is not used */
bkpt->init_count = 1;
bkpt->count = 1;
bkpt->bkpt_inst = db_get_value(bkpt->address, BKPT_SIZE, false);
db_put_value(bkpt->address, BKPT_SIZE,
BKPT_SET(bkpt->bkpt_inst, bkpt->address));
}
void
db_delete_temp_breakpoint(db_breakpoint_t bkpt)
{
db_put_value(bkpt->address, BKPT_SIZE, bkpt->bkpt_inst);
bkpt->address = 0;
}
#endif /* SOFTWARE_SSTEP */