/*
* Kernel Debugger Architecture Independent Breakpoint Handler
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved.
* Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
*/
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kdb.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include "kdb_private.h"
/*
* Table of kdb_breakpoints
*/
kdb_bp_t kdb_breakpoints[KDB_MAXBPT];
static void kdb_setsinglestep(struct pt_regs *regs)
{
KDB_STATE_SET(DOING_SS);
}
static char *kdb_rwtypes[] = {
"Instruction(i)",
"Instruction(Register)",
"Data Write",
"I/O",
"Data Access"
};
static char *kdb_bptype(kdb_bp_t *bp)
{
if (bp->bp_type < 0 || bp->bp_type > 4)
return "";
return kdb_rwtypes[bp->bp_type];
}
static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp)
{
int nextarg = *nextargp;
int diag;
bp->bph_length = 1;
if ((argc + 1) != nextarg) {
if (strncasecmp(argv[nextarg], "datar", sizeof("datar")) == 0)
bp->bp_type = BP_ACCESS_WATCHPOINT;
else if (strncasecmp(argv[nextarg], "dataw", sizeof("dataw")) == 0)
bp->bp_type = BP_WRITE_WATCHPOINT;
else if (strncasecmp(argv[nextarg], "inst", sizeof("inst")) == 0)
bp->bp_type = BP_HARDWARE_BREAKPOINT;
else
return KDB_ARGCOUNT;
bp->bph_length = 1;
nextarg++;
if ((argc + 1) != nextarg) {
unsigned long len;
diag = kdbgetularg((char *)argv[nextarg],
&len);
if (diag)
return diag;
if (len > 8)
return KDB_BADLENGTH;
bp->bph_length = len;
nextarg++;
}
if ((argc + 1) != nextarg)
return KDB_ARGCOUNT;
}
*nextargp = nextarg;
return 0;
}
static int _kdb_bp_remove(kdb_bp_t *bp)
{
int ret = 1;
if (!bp->bp_installed)
return ret;
if (!bp->bp_type)
ret = dbg_remove_sw_break(bp->bp_addr);
else
ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr,
bp->bph_length,
bp->bp_type);
if (ret == 0)
bp->bp_installed = 0;
return ret;
}
static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp)
{
if (KDB_DEBUG(BP))
kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs));
/*
* Setup single step
*/
kdb_setsinglestep(regs);
/*
* Reset delay attribute
*/
bp->bp_delay = 0;
bp->bp_delayed = 1;
}
static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
{
int ret;
/*
* Install the breakpoint, if it is not already installed.
*/
if (KDB_DEBUG(BP))
kdb_printf("%s: bp_installed %d\n",
__func__, bp->bp_installed);
if (!KDB_STATE(SSBPT))
bp->bp_delay = 0;
if (bp->bp_installed)
return 1;
if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) {
if (KDB_DEBUG(BP))
kdb_printf("%s: delayed bp\n", __func__);
kdb_handle_bp(regs, bp);
return 0;
}
if (!bp->bp_type)
ret = dbg_set_sw_break(bp->bp_addr);
else
ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr,
bp->bph_length,
bp->bp_type);
if (ret == 0) {
bp->bp_installed = 1;
} else {
kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
__func__, bp->bp_addr);
if (!bp->bp_type) {
kdb_printf("Software breakpoints are unavailable.\n"
" Boot the kernel with rodata=off\n"
" OR use hw breaks: help bph\n");
}
return 1;
}
return 0;
}
/*
* kdb_bp_install
*
* Install kdb_breakpoints prior to returning from the
* kernel debugger. This allows the kdb_breakpoints to be set
* upon functions that are used internally by kdb, such as
* printk(). This function is only called once per kdb session.
*/
void kdb_bp_install(struct pt_regs *regs)
{
int i;
for (i = 0; i < KDB_MAXBPT; i++) {
kdb_bp_t *bp = &kdb_breakpoints[i];
if (KDB_DEBUG(BP)) {
kdb_printf("%s: bp %d bp_enabled %d\n",
__func__, i, bp->bp_enabled);
}
if (bp->bp_enabled)
_kdb_bp_install(regs, bp);
}
}
/*
* kdb_bp_remove
*
* Remove kdb_breakpoints upon entry to the kernel debugger.
*
* Parameters:
* None.
* Outputs:
* None.
* Returns:
* None.
* Locking:
* None.
* Remarks:
*/
void kdb_bp_remove(void)
{
int i;
for (i = KDB_MAXBPT - 1; i >= 0; i--) {
kdb_bp_t *bp = &kdb_breakpoints[i];
if (KDB_DEBUG(BP)) {
kdb_printf("%s: bp %d bp_enabled %d\n",
__func__, i, bp->bp_enabled);
}
if (bp->bp_enabled)
_kdb_bp_remove(bp);
}
}
/*
* kdb_printbp
*
* Internal function to format and print a breakpoint entry.
*
* Parameters:
* None.
* Outputs:
* None.
* Returns:
* None.
* Locking:
* None.
* Remarks:
*/
static void kdb_printbp(kdb_bp_t *bp, int i)
{
kdb_printf("%s ", kdb_bptype(bp));
kdb_printf("BP #%d at ", i);
kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT);
if (bp->bp_enabled)
kdb_printf("\n is enabled ");
else
kdb_printf("\n is disabled");
kdb_printf(" addr at %016lx, hardtype=%d installed=%d\n",
bp->bp_addr, bp->bp_type, bp->bp_installed);
kdb_printf("\n");
}
/*
* kdb_bp
*
* Handle the bp commands.
*
* [bp|bph] <addr-expression> [DATAR|DATAW]
*
* Parameters:
* argc Count of arguments in argv
* argv Space delimited command line arguments
* Outputs:
* None.
* Returns:
* Zero for success, a kdb diagnostic if failure.
* Locking:
* None.
* Remarks:
*
* bp Set breakpoint on all cpus. Only use hardware assist if need.
* bph Set breakpoint on all cpus. Force hardware register
*/
static int kdb_bp(int argc, const char **argv)
{
int i, bpno;
kdb_bp_t *bp, *bp_check;
int diag;
char *symname = NULL;
long offset = 0ul;
int nextarg;
kdb_bp_t template = {0};
if (argc == 0) {
/*
* Display breakpoint table
*/
for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT;
bpno++, bp++) {
if (bp->bp_free)
continue;
kdb_printbp(bp, bpno);
}
return 0;
}
nextarg = 1;
diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr,
&offset, &symname);
if (diag)
return diag;
if (!template.bp_addr)
return KDB_BADINT;
/*
* This check is redundant (since the breakpoint machinery should
* be doing the same check during kdb_bp_install) but gives the
* user immediate feedback.
*/
diag = kgdb_validate_break_address(template.bp_addr);
if (diag)
return diag;
/*
* Find an empty bp structure to allocate
*/
for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
if (bp->bp_free)
break;
}
if (bpno == KDB_MAXBPT)
return KDB_TOOMANYBPT;
if (strcmp(argv[0], "bph") == 0) {
template.bp_type = BP_HARDWARE_BREAKPOINT;
diag = kdb_parsebp(argc, argv, &nextarg, &template);
if (diag)
return diag;
} else {
template.bp_type = BP_BREAKPOINT;
}
/*
* Check for clashing breakpoints.
*
* Note, in this design we can't have hardware breakpoints
* enabled for both read and write on the same address.
*/
for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT;
i++, bp_check++) {
if (!bp_check->bp_free &&
bp_check->bp_addr == template.bp_addr) {
kdb_printf("You already have a breakpoint at "
kdb_bfd_vma_fmt0 "\n", template.bp_addr);
return KDB_DUPBPT;
}
}
template.bp_enabled = 1;
/*
* Actually allocate the breakpoint found earlier
*/
*bp = template;
bp->bp_free = 0;
kdb_printbp(bp, bpno);
return 0;
}
/*
* kdb_bc
*
* Handles the 'bc', 'be', and 'bd' commands
*
* [bd|bc|be] <breakpoint-number>
* [bd|bc|be] *
*
* Parameters:
* argc Count of arguments in argv
* argv Space delimited command line arguments
* Outputs:
* None.
* Returns:
* Zero for success, a kdb diagnostic for failure
* Locking:
* None.
* Remarks:
*/
static int kdb_bc(int argc, const char **argv)
{
unsigned long addr;
kdb_bp_t *bp = NULL;
int lowbp = KDB_MAXBPT;
int highbp = 0;
int done = 0;
int i;
int diag = 0;
int cmd; /* KDBCMD_B? */
#define KDBCMD_BC 0
#define KDBCMD_BE 1
#define KDBCMD_BD 2
if (strcmp(argv[0], "be") == 0)
cmd = KDBCMD_BE;
else if (strcmp(argv[0], "bd") == 0)
cmd = KDBCMD_BD;
else
cmd = KDBCMD_BC;
if (argc != 1)
return KDB_ARGCOUNT;
if (strcmp(argv[1], "*") == 0) {
lowbp = 0;
highbp = KDB_MAXBPT;
} else {
diag = kdbgetularg(argv[1], &addr);
if (diag)
return diag;
/*
* For addresses less than the maximum breakpoint number,
* assume that the breakpoint number is desired.
*/
if (addr < KDB_MAXBPT) {
lowbp = highbp = addr;
highbp++;
} else {
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT;
i++, bp++) {
if (bp->bp_addr == addr) {
lowbp = highbp = i;
highbp++;
break;
}
}
}
}
/*
* Now operate on the set of breakpoints matching the input
* criteria (either '*' for all, or an individual breakpoint).
*/
for (bp = &kdb_breakpoints[lowbp], i = lowbp;
i < highbp;
i++, bp++) {
if (bp->bp_free)
continue;
done++;
switch (cmd) {
case KDBCMD_BC:
bp->bp_enabled = 0;
kdb_printf("Breakpoint %d at "
kdb_bfd_vma_fmt " cleared\n",
i, bp->bp_addr);
bp->bp_addr = 0;
bp->bp_free = 1;
break;
case KDBCMD_BE:
bp->bp_enabled = 1;
kdb_printf("Breakpoint %d at "
kdb_bfd_vma_fmt " enabled",
i, bp->bp_addr);
kdb_printf("\n");
break;
case KDBCMD_BD:
if (!bp->bp_enabled)
break;
bp->bp_enabled = 0;
kdb_printf("Breakpoint %d at "
kdb_bfd_vma_fmt " disabled\n",
i, bp->bp_addr);
break;
}
if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
bp->bp_delay = 0;
KDB_STATE_CLEAR(SSBPT);
}
}
return (!done) ? KDB_BPTNOTFOUND : 0;
}
/*
* kdb_ss
*
* Process the 'ss' (Single Step) command.
*
* ss
*
* Parameters:
* argc Argument count
* argv Argument vector
* Outputs:
* None.
* Returns:
* KDB_CMD_SS for success, a kdb error if failure.
* Locking:
* None.
* Remarks:
*
* Set the arch specific option to trigger a debug trap after the next
* instruction.
*/
static int kdb_ss(int argc, const char **argv)
{
if (argc != 0)
return KDB_ARGCOUNT;
/*
* Set trace flag and go.
*/
KDB_STATE_SET(DOING_SS);
return KDB_CMD_SS;
}
static kdbtab_t bptab[] = {
{ .name = "bp",
.func = kdb_bp,
.usage = "[<vaddr>]",
.help = "Set/Display breakpoints",
.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
},
{ .name = "bl",
.func = kdb_bp,
.usage = "[<vaddr>]",
.help = "Display breakpoints",
.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
},
{ .name = "bc",
.func = kdb_bc,
.usage = "<bpnum>",
.help = "Clear Breakpoint",
.flags = KDB_ENABLE_FLOW_CTRL,
},
{ .name = "be",
.func = kdb_bc,
.usage = "<bpnum>",
.help = "Enable Breakpoint",
.flags = KDB_ENABLE_FLOW_CTRL,
},
{ .name = "bd",
.func = kdb_bc,
.usage = "<bpnum>",
.help = "Disable Breakpoint",
.flags = KDB_ENABLE_FLOW_CTRL,
},
{ .name = "ss",
.func = kdb_ss,
.usage = "",
.help = "Single Step",
.minlen = 1,
.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
},
};
static kdbtab_t bphcmd = {
.name = "bph",
.func = kdb_bp,
.usage = "[<vaddr>]",
.help = "[datar [length]|dataw [length]] Set hw brk",
.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
};
/* Initialize the breakpoint table and register breakpoint commands. */
void __init kdb_initbptab(void)
{
int i;
kdb_bp_t *bp;
/*
* First time initialization.
*/
memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints));
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++)
bp->bp_free = 1;
kdb_register_table(bptab, ARRAY_SIZE(bptab));
if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)
kdb_register_table(&bphcmd, 1);
}
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