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linux-sg2042/kernel/debug/gdbstub.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel Debug Core
*
* Maintainer: Jason Wessel <jason.wessel@windriver.com>
*
* Copyright (C) 2000-2001 VERITAS Software Corporation.
* Copyright (C) 2002-2004 Timesys Corporation
* Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
* Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
* Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
* Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
* Copyright (C) 2005-2009 Wind River Systems, Inc.
* Copyright (C) 2007 MontaVista Software, Inc.
* Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*
* Contributors at various stages not listed above:
* Jason Wessel ( jason.wessel@windriver.com )
* George Anzinger <george@mvista.com>
* Anurekh Saxena (anurekh.saxena@timesys.com)
* Lake Stevens Instrument Division (Glenn Engel)
* Jim Kingdon, Cygnus Support.
*
* Original KGDB stub: David Grothe <dave@gcom.com>,
* Tigran Aivazian <tigran@sco.com>
*/
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/serial_core.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/unaligned.h>
#include "debug_core.h"
#define KGDB_MAX_THREAD_QUERY 17
/* Our I/O buffers. */
static char remcom_in_buffer[BUFMAX];
static char remcom_out_buffer[BUFMAX];
static int gdbstub_use_prev_in_buf;
static int gdbstub_prev_in_buf_pos;
/* Storage for the registers, in GDB format. */
static unsigned long gdb_regs[(NUMREGBYTES +
sizeof(unsigned long) - 1) /
sizeof(unsigned long)];
/*
* GDB remote protocol parser:
*/
#ifdef CONFIG_KGDB_KDB
static int gdbstub_read_wait(void)
{
int ret = -1;
int i;
if (unlikely(gdbstub_use_prev_in_buf)) {
if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
else
gdbstub_use_prev_in_buf = 0;
}
/* poll any additional I/O interfaces that are defined */
while (ret < 0)
for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
ret = kdb_poll_funcs[i]();
if (ret > 0)
break;
}
return ret;
}
#else
static int gdbstub_read_wait(void)
{
int ret = dbg_io_ops->read_char();
while (ret == NO_POLL_CHAR)
ret = dbg_io_ops->read_char();
return ret;
}
#endif
/* scan for the sequence $<data>#<checksum> */
static void get_packet(char *buffer)
{
unsigned char checksum;
unsigned char xmitcsum;
int count;
char ch;
do {
/*
* Spin and wait around for the start character, ignore all
* other characters:
*/
while ((ch = (gdbstub_read_wait())) != '$')
/* nothing */;
kgdb_connected = 1;
checksum = 0;
xmitcsum = -1;
count = 0;
/*
* now, read until a # or end of buffer is found:
*/
while (count < (BUFMAX - 1)) {
ch = gdbstub_read_wait();
if (ch == '#')
break;
checksum = checksum + ch;
buffer[count] = ch;
count = count + 1;
}
if (ch == '#') {
xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
xmitcsum += hex_to_bin(gdbstub_read_wait());
if (checksum != xmitcsum)
/* failed checksum */
dbg_io_ops->write_char('-');
else
/* successful transfer */
dbg_io_ops->write_char('+');
if (dbg_io_ops->flush)
dbg_io_ops->flush();
}
buffer[count] = 0;
} while (checksum != xmitcsum);
}
/*
* Send the packet in buffer.
* Check for gdb connection if asked for.
*/
static void put_packet(char *buffer)
{
unsigned char checksum;
int count;
char ch;
/*
* $<packet info>#<checksum>.
*/
while (1) {
dbg_io_ops->write_char('$');
checksum = 0;
count = 0;
while ((ch = buffer[count])) {
dbg_io_ops->write_char(ch);
checksum += ch;
count++;
}
dbg_io_ops->write_char('#');
dbg_io_ops->write_char(hex_asc_hi(checksum));
dbg_io_ops->write_char(hex_asc_lo(checksum));
if (dbg_io_ops->flush)
dbg_io_ops->flush();
/* Now see what we get in reply. */
ch = gdbstub_read_wait();
if (ch == 3)
ch = gdbstub_read_wait();
/* If we get an ACK, we are done. */
if (ch == '+')
return;
/*
* If we get the start of another packet, this means
* that GDB is attempting to reconnect. We will NAK
* the packet being sent, and stop trying to send this
* packet.
*/
if (ch == '$') {
dbg_io_ops->write_char('-');
if (dbg_io_ops->flush)
dbg_io_ops->flush();
return;
}
}
}
static char gdbmsgbuf[BUFMAX + 1];
void gdbstub_msg_write(const char *s, int len)
{
char *bufptr;
int wcount;
int i;
if (len == 0)
len = strlen(s);
/* 'O'utput */
gdbmsgbuf[0] = 'O';
/* Fill and send buffers... */
while (len > 0) {
bufptr = gdbmsgbuf + 1;
/* Calculate how many this time */
if ((len << 1) > (BUFMAX - 2))
wcount = (BUFMAX - 2) >> 1;
else
wcount = len;
/* Pack in hex chars */
for (i = 0; i < wcount; i++)
bufptr = hex_byte_pack(bufptr, s[i]);
*bufptr = '\0';
/* Move up */
s += wcount;
len -= wcount;
/* Write packet */
put_packet(gdbmsgbuf);
}
}
/*
* Convert the memory pointed to by mem into hex, placing result in
* buf. Return a pointer to the last char put in buf (null). May
* return an error.
*/
char *kgdb_mem2hex(char *mem, char *buf, int count)
{
char *tmp;
int err;
/*
* We use the upper half of buf as an intermediate buffer for the
* raw memory copy. Hex conversion will work against this one.
*/
tmp = buf + count;
err = copy_from_kernel_nofault(tmp, mem, count);
if (err)
return NULL;
while (count > 0) {
buf = hex_byte_pack(buf, *tmp);
tmp++;
count--;
}
*buf = 0;
return buf;
}
/*
* Convert the hex array pointed to by buf into binary to be placed in
* mem. Return a pointer to the character AFTER the last byte
* written. May return an error.
*/
int kgdb_hex2mem(char *buf, char *mem, int count)
{
char *tmp_raw;
char *tmp_hex;
/*
* We use the upper half of buf as an intermediate buffer for the
* raw memory that is converted from hex.
*/
tmp_raw = buf + count * 2;
tmp_hex = tmp_raw - 1;
while (tmp_hex >= buf) {
tmp_raw--;
*tmp_raw = hex_to_bin(*tmp_hex--);
*tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
}
return copy_to_kernel_nofault(mem, tmp_raw, count);
}
/*
* While we find nice hex chars, build a long_val.
* Return number of chars processed.
*/
int kgdb_hex2long(char **ptr, unsigned long *long_val)
{
int hex_val;
int num = 0;
int negate = 0;
*long_val = 0;
if (**ptr == '-') {
negate = 1;
(*ptr)++;
}
while (**ptr) {
hex_val = hex_to_bin(**ptr);
if (hex_val < 0)
break;
*long_val = (*long_val << 4) | hex_val;
num++;
(*ptr)++;
}
if (negate)
*long_val = -*long_val;
return num;
}
/*
* Copy the binary array pointed to by buf into mem. Fix $, #, and
* 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
* The input buf is overwritten with the result to write to mem.
*/
static int kgdb_ebin2mem(char *buf, char *mem, int count)
{
int size = 0;
char *c = buf;
while (count-- > 0) {
c[size] = *buf++;
if (c[size] == 0x7d)
c[size] = *buf++ ^ 0x20;
size++;
}
return copy_to_kernel_nofault(mem, c, size);
}
#if DBG_MAX_REG_NUM > 0
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
int i;
int idx = 0;
char *ptr = (char *)gdb_regs;
for (i = 0; i < DBG_MAX_REG_NUM; i++) {
dbg_get_reg(i, ptr + idx, regs);
idx += dbg_reg_def[i].size;
}
}
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
int i;
int idx = 0;
char *ptr = (char *)gdb_regs;
for (i = 0; i < DBG_MAX_REG_NUM; i++) {
dbg_set_reg(i, ptr + idx, regs);
idx += dbg_reg_def[i].size;
}
}
#endif /* DBG_MAX_REG_NUM > 0 */
/* Write memory due to an 'M' or 'X' packet. */
static int write_mem_msg(int binary)
{
char *ptr = &remcom_in_buffer[1];
unsigned long addr;
unsigned long length;
int err;
if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
if (binary)
err = kgdb_ebin2mem(ptr, (char *)addr, length);
else
err = kgdb_hex2mem(ptr, (char *)addr, length);
if (err)
return err;
if (CACHE_FLUSH_IS_SAFE)
flush_icache_range(addr, addr + length);
return 0;
}
return -EINVAL;
}
static void error_packet(char *pkt, int error)
{
error = -error;
pkt[0] = 'E';
pkt[1] = hex_asc[(error / 10)];
pkt[2] = hex_asc[(error % 10)];
pkt[3] = '\0';
}
/*
* Thread ID accessors. We represent a flat TID space to GDB, where
* the per CPU idle threads (which under Linux all have PID 0) are
* remapped to negative TIDs.
*/
#define BUF_THREAD_ID_SIZE 8
static char *pack_threadid(char *pkt, unsigned char *id)
{
unsigned char *limit;
int lzero = 1;
limit = id + (BUF_THREAD_ID_SIZE / 2);
while (id < limit) {
if (!lzero || *id != 0) {
pkt = hex_byte_pack(pkt, *id);
lzero = 0;
}
id++;
}
if (lzero)
pkt = hex_byte_pack(pkt, 0);
return pkt;
}
static void int_to_threadref(unsigned char *id, int value)
{
put_unaligned_be32(value, id);
}
static struct task_struct *getthread(struct pt_regs *regs, int tid)
{
/*
* Non-positive TIDs are remapped to the cpu shadow information
*/
if (tid == 0 || tid == -1)
tid = -atomic_read(&kgdb_active) - 2;
if (tid < -1 && tid > -NR_CPUS - 2) {
if (kgdb_info[-tid - 2].task)
return kgdb_info[-tid - 2].task;
else
return idle_task(-tid - 2);
}
if (tid <= 0) {
printk(KERN_ERR "KGDB: Internal thread select error\n");
dump_stack();
return NULL;
}
/*
* find_task_by_pid_ns() does not take the tasklist lock anymore
* but is nicely RCU locked - hence is a pretty resilient
* thing to use:
*/
return find_task_by_pid_ns(tid, &init_pid_ns);
}
/*
* Remap normal tasks to their real PID,
* CPU shadow threads are mapped to -CPU - 2
*/
static inline int shadow_pid(int realpid)
{
if (realpid)
return realpid;
return -raw_smp_processor_id() - 2;
}
/*
* All the functions that start with gdb_cmd are the various
* operations to implement the handlers for the gdbserial protocol
* where KGDB is communicating with an external debugger
*/
/* Handle the '?' status packets */
static void gdb_cmd_status(struct kgdb_state *ks)
{
/*
* We know that this packet is only sent
* during initial connect. So to be safe,
* we clear out our breakpoints now in case
* GDB is reconnecting.
*/
dbg_remove_all_break();
remcom_out_buffer[0] = 'S';
hex_byte_pack(&remcom_out_buffer[1], ks->signo);
}
static void gdb_get_regs_helper(struct kgdb_state *ks)
{
struct task_struct *thread;
void *local_debuggerinfo;
int i;
thread = kgdb_usethread;
if (!thread) {
thread = kgdb_info[ks->cpu].task;
local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
} else {
local_debuggerinfo = NULL;
for_each_online_cpu(i) {
/*
* Try to find the task on some other
* or possibly this node if we do not
* find the matching task then we try
* to approximate the results.
*/
if (thread == kgdb_info[i].task)
local_debuggerinfo = kgdb_info[i].debuggerinfo;
}
}
/*
* All threads that don't have debuggerinfo should be
* in schedule() sleeping, since all other CPUs
* are in kgdb_wait, and thus have debuggerinfo.
*/
if (local_debuggerinfo) {
pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
} else {
/*
* Pull stuff saved during switch_to; nothing
* else is accessible (or even particularly
* relevant).
*
* This should be enough for a stack trace.
*/
sleeping_thread_to_gdb_regs(gdb_regs, thread);
}
}
/* Handle the 'g' get registers request */
static void gdb_cmd_getregs(struct kgdb_state *ks)
{
gdb_get_regs_helper(ks);
kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
}
/* Handle the 'G' set registers request */
static void gdb_cmd_setregs(struct kgdb_state *ks)
{
kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
if (kgdb_usethread && kgdb_usethread != current) {
error_packet(remcom_out_buffer, -EINVAL);
} else {
gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
strcpy(remcom_out_buffer, "OK");
}
}
/* Handle the 'm' memory read bytes */
static void gdb_cmd_memread(struct kgdb_state *ks)
{
char *ptr = &remcom_in_buffer[1];
unsigned long length;
unsigned long addr;
char *err;
if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
kgdb_hex2long(&ptr, &length) > 0) {
err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
if (!err)
error_packet(remcom_out_buffer, -EINVAL);
} else {
error_packet(remcom_out_buffer, -EINVAL);
}
}
/* Handle the 'M' memory write bytes */
static void gdb_cmd_memwrite(struct kgdb_state *ks)
{
int err = write_mem_msg(0);
if (err)
error_packet(remcom_out_buffer, err);
else
strcpy(remcom_out_buffer, "OK");
}
#if DBG_MAX_REG_NUM > 0
static char *gdb_hex_reg_helper(int regnum, char *out)
{
int i;
int offset = 0;
for (i = 0; i < regnum; i++)
offset += dbg_reg_def[i].size;
return kgdb_mem2hex((char *)gdb_regs + offset, out,
dbg_reg_def[i].size);
}
/* Handle the 'p' individual register get */
static void gdb_cmd_reg_get(struct kgdb_state *ks)
{
unsigned long regnum;
char *ptr = &remcom_in_buffer[1];
kgdb_hex2long(&ptr, &regnum);
if (regnum >= DBG_MAX_REG_NUM) {
error_packet(remcom_out_buffer, -EINVAL);
return;
}
gdb_get_regs_helper(ks);
gdb_hex_reg_helper(regnum, remcom_out_buffer);
}
/* Handle the 'P' individual register set */
static void gdb_cmd_reg_set(struct kgdb_state *ks)
{
unsigned long regnum;
char *ptr = &remcom_in_buffer[1];
int i = 0;
kgdb_hex2long(&ptr, &regnum);
if (*ptr++ != '=' ||
!(!kgdb_usethread || kgdb_usethread == current) ||
!dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
error_packet(remcom_out_buffer, -EINVAL);
return;
}
memset(gdb_regs, 0, sizeof(gdb_regs));
while (i < sizeof(gdb_regs) * 2)
if (hex_to_bin(ptr[i]) >= 0)
i++;
else
break;
i = i / 2;
kgdb_hex2mem(ptr, (char *)gdb_regs, i);
dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
strcpy(remcom_out_buffer, "OK");
}
#endif /* DBG_MAX_REG_NUM > 0 */
/* Handle the 'X' memory binary write bytes */
static void gdb_cmd_binwrite(struct kgdb_state *ks)
{
int err = write_mem_msg(1);
if (err)
error_packet(remcom_out_buffer, err);
else
strcpy(remcom_out_buffer, "OK");
}
/* Handle the 'D' or 'k', detach or kill packets */
static void gdb_cmd_detachkill(struct kgdb_state *ks)
{
int error;
/* The detach case */
if (remcom_in_buffer[0] == 'D') {
error = dbg_remove_all_break();
if (error < 0) {
error_packet(remcom_out_buffer, error);
} else {
strcpy(remcom_out_buffer, "OK");
kgdb_connected = 0;
}
put_packet(remcom_out_buffer);
} else {
/*
* Assume the kill case, with no exit code checking,
* trying to force detach the debugger:
*/
dbg_remove_all_break();
kgdb_connected = 0;
}
}
/* Handle the 'R' reboot packets */
static int gdb_cmd_reboot(struct kgdb_state *ks)
{
/* For now, only honor R0 */
if (strcmp(remcom_in_buffer, "R0") == 0) {
printk(KERN_CRIT "Executing emergency reboot\n");
strcpy(remcom_out_buffer, "OK");
put_packet(remcom_out_buffer);
/*
* Execution should not return from
* machine_emergency_restart()
*/
machine_emergency_restart();
kgdb_connected = 0;
return 1;
}
return 0;
}
/* Handle the 'q' query packets */
static void gdb_cmd_query(struct kgdb_state *ks)
{
struct task_struct *g;
struct task_struct *p;
unsigned char thref[BUF_THREAD_ID_SIZE];
char *ptr;
int i;
int cpu;
int finished = 0;
switch (remcom_in_buffer[1]) {
case 's':
case 'f':
if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
break;
i = 0;
remcom_out_buffer[0] = 'm';
ptr = remcom_out_buffer + 1;
if (remcom_in_buffer[1] == 'f') {
/* Each cpu is a shadow thread */
for_each_online_cpu(cpu) {
ks->thr_query = 0;
int_to_threadref(thref, -cpu - 2);
ptr = pack_threadid(ptr, thref);
*(ptr++) = ',';
i++;
}
}
for_each_process_thread(g, p) {
if (i >= ks->thr_query && !finished) {
int_to_threadref(thref, p->pid);
ptr = pack_threadid(ptr, thref);
*(ptr++) = ',';
ks->thr_query++;
if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
finished = 1;
}
i++;
}
*(--ptr) = '\0';
break;
case 'C':
/* Current thread id */
strcpy(remcom_out_buffer, "QC");
ks->threadid = shadow_pid(current->pid);
int_to_threadref(thref, ks->threadid);
pack_threadid(remcom_out_buffer + 2, thref);
break;
case 'T':
if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
break;
ks->threadid = 0;
ptr = remcom_in_buffer + 17;
kgdb_hex2long(&ptr, &ks->threadid);
if (!getthread(ks->linux_regs, ks->threadid)) {
error_packet(remcom_out_buffer, -EINVAL);
break;
}
if ((int)ks->threadid > 0) {
kgdb_mem2hex(getthread(ks->linux_regs,
ks->threadid)->comm,
remcom_out_buffer, 16);
} else {
static char tmpstr[23 + BUF_THREAD_ID_SIZE];
sprintf(tmpstr, "shadowCPU%d",
(int)(-ks->threadid - 2));
kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
}
break;
#ifdef CONFIG_KGDB_KDB
case 'R':
if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
int len = strlen(remcom_in_buffer + 6);
if ((len % 2) != 0) {
strcpy(remcom_out_buffer, "E01");
break;
}
kgdb_hex2mem(remcom_in_buffer + 6,
remcom_out_buffer, len);
len = len / 2;
remcom_out_buffer[len++] = 0;
kdb_common_init_state(ks);
kdb_parse(remcom_out_buffer);
kdb_common_deinit_state();
strcpy(remcom_out_buffer, "OK");
}
break;
#endif
#ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
case 'S':
if (!strncmp(remcom_in_buffer, "qSupported:", 11))
strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature);
break;
case 'X':
if (!strncmp(remcom_in_buffer, "qXfer:", 6))
kgdb_arch_handle_qxfer_pkt(remcom_in_buffer,
remcom_out_buffer);
break;
#endif
default:
break;
}
}
/* Handle the 'H' task query packets */
static void gdb_cmd_task(struct kgdb_state *ks)
{
struct task_struct *thread;
char *ptr;
switch (remcom_in_buffer[1]) {
case 'g':
ptr = &remcom_in_buffer[2];
kgdb_hex2long(&ptr, &ks->threadid);
thread = getthread(ks->linux_regs, ks->threadid);
if (!thread && ks->threadid > 0) {
error_packet(remcom_out_buffer, -EINVAL);
break;
}
kgdb_usethread = thread;
ks->kgdb_usethreadid = ks->threadid;
strcpy(remcom_out_buffer, "OK");
break;
case 'c':
ptr = &remcom_in_buffer[2];
kgdb_hex2long(&ptr, &ks->threadid);
if (!ks->threadid) {
kgdb_contthread = NULL;
} else {
thread = getthread(ks->linux_regs, ks->threadid);
if (!thread && ks->threadid > 0) {
error_packet(remcom_out_buffer, -EINVAL);
break;
}
kgdb_contthread = thread;
}
strcpy(remcom_out_buffer, "OK");
break;
}
}
/* Handle the 'T' thread query packets */
static void gdb_cmd_thread(struct kgdb_state *ks)
{
char *ptr = &remcom_in_buffer[1];
struct task_struct *thread;
kgdb_hex2long(&ptr, &ks->threadid);
thread = getthread(ks->linux_regs, ks->threadid);
if (thread)
strcpy(remcom_out_buffer, "OK");
else
error_packet(remcom_out_buffer, -EINVAL);
}
/* Handle the 'z' or 'Z' breakpoint remove or set packets */
static void gdb_cmd_break(struct kgdb_state *ks)
{
/*
* Since GDB-5.3, it's been drafted that '0' is a software
* breakpoint, '1' is a hardware breakpoint, so let's do that.
*/
char *bpt_type = &remcom_in_buffer[1];
char *ptr = &remcom_in_buffer[2];
unsigned long addr;
unsigned long length;
int error = 0;
if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
/* Unsupported */
if (*bpt_type > '4')
return;
} else {
if (*bpt_type != '0' && *bpt_type != '1')
/* Unsupported. */
return;
}
/*
* Test if this is a hardware breakpoint, and
* if we support it:
*/
if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
/* Unsupported. */
return;
if (*(ptr++) != ',') {
error_packet(remcom_out_buffer, -EINVAL);
return;
}
if (!kgdb_hex2long(&ptr, &addr)) {
error_packet(remcom_out_buffer, -EINVAL);
return;
}
if (*(ptr++) != ',' ||
!kgdb_hex2long(&ptr, &length)) {
error_packet(remcom_out_buffer, -EINVAL);
return;
}
if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
error = dbg_set_sw_break(addr);
else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
error = dbg_remove_sw_break(addr);
else if (remcom_in_buffer[0] == 'Z')
error = arch_kgdb_ops.set_hw_breakpoint(addr,
(int)length, *bpt_type - '0');
else if (remcom_in_buffer[0] == 'z')
error = arch_kgdb_ops.remove_hw_breakpoint(addr,
(int) length, *bpt_type - '0');
if (error == 0)
strcpy(remcom_out_buffer, "OK");
else
error_packet(remcom_out_buffer, error);
}
/* Handle the 'C' signal / exception passing packets */
static int gdb_cmd_exception_pass(struct kgdb_state *ks)
{
/* C09 == pass exception
* C15 == detach kgdb, pass exception
*/
if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
ks->pass_exception = 1;
remcom_in_buffer[0] = 'c';
} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
ks->pass_exception = 1;
remcom_in_buffer[0] = 'D';
dbg_remove_all_break();
kgdb_connected = 0;
return 1;
} else {
gdbstub_msg_write("KGDB only knows signal 9 (pass)"
" and 15 (pass and disconnect)\n"
"Executing a continue without signal passing\n", 0);
remcom_in_buffer[0] = 'c';
}
/* Indicate fall through */
return -1;
}
/*
* This function performs all gdbserial command processing
*/
int gdb_serial_stub(struct kgdb_state *ks)
{
int error = 0;
int tmp;
/* Initialize comm buffer and globals. */
memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
kgdb_usethread = kgdb_info[ks->cpu].task;
ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
ks->pass_exception = 0;
if (kgdb_connected) {
unsigned char thref[BUF_THREAD_ID_SIZE];
char *ptr;
/* Reply to host that an exception has occurred */
ptr = remcom_out_buffer;
*ptr++ = 'T';
ptr = hex_byte_pack(ptr, ks->signo);
ptr += strlen(strcpy(ptr, "thread:"));
int_to_threadref(thref, shadow_pid(current->pid));
ptr = pack_threadid(ptr, thref);
*ptr++ = ';';
put_packet(remcom_out_buffer);
}
while (1) {
error = 0;
/* Clear the out buffer. */
memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
get_packet(remcom_in_buffer);
switch (remcom_in_buffer[0]) {
case '?': /* gdbserial status */
gdb_cmd_status(ks);
break;
case 'g': /* return the value of the CPU registers */
gdb_cmd_getregs(ks);
break;
case 'G': /* set the value of the CPU registers - return OK */
gdb_cmd_setregs(ks);
break;
case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
gdb_cmd_memread(ks);
break;
case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
gdb_cmd_memwrite(ks);
break;
#if DBG_MAX_REG_NUM > 0
case 'p': /* pXX Return gdb register XX (in hex) */
gdb_cmd_reg_get(ks);
break;
case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
gdb_cmd_reg_set(ks);
break;
#endif /* DBG_MAX_REG_NUM > 0 */
case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
gdb_cmd_binwrite(ks);
break;
/* kill or detach. KGDB should treat this like a
* continue.
*/
case 'D': /* Debugger detach */
case 'k': /* Debugger detach via kill */
gdb_cmd_detachkill(ks);
goto default_handle;
case 'R': /* Reboot */
if (gdb_cmd_reboot(ks))
goto default_handle;
break;
case 'q': /* query command */
gdb_cmd_query(ks);
break;
case 'H': /* task related */
gdb_cmd_task(ks);
break;
case 'T': /* Query thread status */
gdb_cmd_thread(ks);
break;
case 'z': /* Break point remove */
case 'Z': /* Break point set */
gdb_cmd_break(ks);
break;
#ifdef CONFIG_KGDB_KDB
case '3': /* Escape into back into kdb */
if (remcom_in_buffer[1] == '\0') {
gdb_cmd_detachkill(ks);
return DBG_PASS_EVENT;
}
fallthrough;
#endif
case 'C': /* Exception passing */
tmp = gdb_cmd_exception_pass(ks);
if (tmp > 0)
goto default_handle;
if (tmp == 0)
break;
fallthrough; /* on tmp < 0 */
case 'c': /* Continue packet */
case 's': /* Single step packet */
if (kgdb_contthread && kgdb_contthread != current) {
/* Can't switch threads in kgdb */
error_packet(remcom_out_buffer, -EINVAL);
break;
}
fallthrough; /* to default processing */
default:
default_handle:
error = kgdb_arch_handle_exception(ks->ex_vector,
ks->signo,
ks->err_code,
remcom_in_buffer,
remcom_out_buffer,
ks->linux_regs);
/*
* Leave cmd processing on error, detach,
* kill, continue, or single step.
*/
if (error >= 0 || remcom_in_buffer[0] == 'D' ||
remcom_in_buffer[0] == 'k') {
error = 0;
goto kgdb_exit;
}
}
/* reply to the request */
put_packet(remcom_out_buffer);
}
kgdb_exit:
if (ks->pass_exception)
error = 1;
return error;
}
int gdbstub_state(struct kgdb_state *ks, char *cmd)
{
int error;
switch (cmd[0]) {
case 'e':
error = kgdb_arch_handle_exception(ks->ex_vector,
ks->signo,
ks->err_code,
remcom_in_buffer,
remcom_out_buffer,
ks->linux_regs);
return error;
case 's':
case 'c':
strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
return 0;
case '$':
strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
gdbstub_prev_in_buf_pos = 0;
return 0;
}
dbg_io_ops->write_char('+');
put_packet(remcom_out_buffer);
return 0;
}
/**
* gdbstub_exit - Send an exit message to GDB
* @status: The exit code to report.
*/
void gdbstub_exit(int status)
{
unsigned char checksum, ch, buffer[3];
int loop;
if (!kgdb_connected)
return;
kgdb_connected = 0;
if (!dbg_io_ops || dbg_kdb_mode)
return;
buffer[0] = 'W';
buffer[1] = hex_asc_hi(status);
buffer[2] = hex_asc_lo(status);
dbg_io_ops->write_char('$');
checksum = 0;
for (loop = 0; loop < 3; loop++) {
ch = buffer[loop];
checksum += ch;
dbg_io_ops->write_char(ch);
}
dbg_io_ops->write_char('#');
dbg_io_ops->write_char(hex_asc_hi(checksum));
dbg_io_ops->write_char(hex_asc_lo(checksum));
/* make sure the output is flushed, lest the bootloader clobber it */
if (dbg_io_ops->flush)
dbg_io_ops->flush();
}
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