/*
* gdb server stub
*
* This implements a subset of the remote protocol as described in:
*
* https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
*
* Copyright (c) 2003-2005 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: LGPL-2.0+
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/ctype.h"
#include "qemu/cutils.h"
#include "qemu/module.h"
#include "trace-root.h"
#ifdef CONFIG_USER_ONLY
#include "qemu.h"
#else
#include "monitor/monitor.h"
#include "chardev/char.h"
#include "chardev/char-fe.h"
#include "sysemu/sysemu.h"
#include "exec/gdbstub.h"
#include "hw/cpu/cluster.h"
#include "hw/boards.h"
#endif
#define MAX_PACKET_LENGTH 4096
#include "qemu/sockets.h"
#include "sysemu/hw_accel.h"
#include "sysemu/kvm.h"
#include "sysemu/runstate.h"
#include "hw/semihosting/semihost.h"
#include "exec/exec-all.h"
#ifdef CONFIG_USER_ONLY
#define GDB_ATTACHED "0"
#else
#define GDB_ATTACHED "1"
#endif
#ifndef CONFIG_USER_ONLY
static int phy_memory_mode;
#endif
static inline int target_memory_rw_debug(CPUState *cpu, target_ulong addr,
uint8_t *buf, int len, bool is_write)
{
CPUClass *cc;
#ifndef CONFIG_USER_ONLY
if (phy_memory_mode) {
if (is_write) {
cpu_physical_memory_write(addr, buf, len);
} else {
cpu_physical_memory_read(addr, buf, len);
}
return 0;
}
#endif
cc = CPU_GET_CLASS(cpu);
if (cc->memory_rw_debug) {
return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
}
return cpu_memory_rw_debug(cpu, addr, buf, len, is_write);
}
/* Return the GDB index for a given vCPU state.
*
* For user mode this is simply the thread id. In system mode GDB
* numbers CPUs from 1 as 0 is reserved as an "any cpu" index.
*/
static inline int cpu_gdb_index(CPUState *cpu)
{
#if defined(CONFIG_USER_ONLY)
TaskState *ts = (TaskState *) cpu->opaque;
return ts->ts_tid;
#else
return cpu->cpu_index + 1;
#endif
}
enum {
GDB_SIGNAL_0 = 0,
GDB_SIGNAL_INT = 2,
GDB_SIGNAL_QUIT = 3,
GDB_SIGNAL_TRAP = 5,
GDB_SIGNAL_ABRT = 6,
GDB_SIGNAL_ALRM = 14,
GDB_SIGNAL_IO = 23,
GDB_SIGNAL_XCPU = 24,
GDB_SIGNAL_UNKNOWN = 143
};
#ifdef CONFIG_USER_ONLY
/* Map target signal numbers to GDB protocol signal numbers and vice
* versa. For user emulation's currently supported systems, we can
* assume most signals are defined.
*/
static int gdb_signal_table[] = {
0,
TARGET_SIGHUP,
TARGET_SIGINT,
TARGET_SIGQUIT,
TARGET_SIGILL,
TARGET_SIGTRAP,
TARGET_SIGABRT,
-1, /* SIGEMT */
TARGET_SIGFPE,
TARGET_SIGKILL,
TARGET_SIGBUS,
TARGET_SIGSEGV,
TARGET_SIGSYS,
TARGET_SIGPIPE,
TARGET_SIGALRM,
TARGET_SIGTERM,
TARGET_SIGURG,
TARGET_SIGSTOP,
TARGET_SIGTSTP,
TARGET_SIGCONT,
TARGET_SIGCHLD,
TARGET_SIGTTIN,
TARGET_SIGTTOU,
TARGET_SIGIO,
TARGET_SIGXCPU,
TARGET_SIGXFSZ,
TARGET_SIGVTALRM,
TARGET_SIGPROF,
TARGET_SIGWINCH,
-1, /* SIGLOST */
TARGET_SIGUSR1,
TARGET_SIGUSR2,
#ifdef TARGET_SIGPWR
TARGET_SIGPWR,
#else
-1,
#endif
-1, /* SIGPOLL */
-1,
-1,
-1,
-1,
-1,
-1,
-1,
-1,
-1,
-1,
-1,
#ifdef __SIGRTMIN
__SIGRTMIN + 1,
__SIGRTMIN + 2,
__SIGRTMIN + 3,
__SIGRTMIN + 4,
__SIGRTMIN + 5,
__SIGRTMIN + 6,
__SIGRTMIN + 7,
__SIGRTMIN + 8,
__SIGRTMIN + 9,
__SIGRTMIN + 10,
__SIGRTMIN + 11,
__SIGRTMIN + 12,
__SIGRTMIN + 13,
__SIGRTMIN + 14,
__SIGRTMIN + 15,
__SIGRTMIN + 16,
__SIGRTMIN + 17,
__SIGRTMIN + 18,
__SIGRTMIN + 19,
__SIGRTMIN + 20,
__SIGRTMIN + 21,
__SIGRTMIN + 22,
__SIGRTMIN + 23,
__SIGRTMIN + 24,
__SIGRTMIN + 25,
__SIGRTMIN + 26,
__SIGRTMIN + 27,
__SIGRTMIN + 28,
__SIGRTMIN + 29,
__SIGRTMIN + 30,
__SIGRTMIN + 31,
-1, /* SIGCANCEL */
__SIGRTMIN,
__SIGRTMIN + 32,
__SIGRTMIN + 33,
__SIGRTMIN + 34,
__SIGRTMIN + 35,
__SIGRTMIN + 36,
__SIGRTMIN + 37,
__SIGRTMIN + 38,
__SIGRTMIN + 39,
__SIGRTMIN + 40,
__SIGRTMIN + 41,
__SIGRTMIN + 42,
__SIGRTMIN + 43,
__SIGRTMIN + 44,
__SIGRTMIN + 45,
__SIGRTMIN + 46,
__SIGRTMIN + 47,
__SIGRTMIN + 48,
__SIGRTMIN + 49,
__SIGRTMIN + 50,
__SIGRTMIN + 51,
__SIGRTMIN + 52,
__SIGRTMIN + 53,
__SIGRTMIN + 54,
__SIGRTMIN + 55,
__SIGRTMIN + 56,
__SIGRTMIN + 57,
__SIGRTMIN + 58,
__SIGRTMIN + 59,
__SIGRTMIN + 60,
__SIGRTMIN + 61,
__SIGRTMIN + 62,
__SIGRTMIN + 63,
__SIGRTMIN + 64,
__SIGRTMIN + 65,
__SIGRTMIN + 66,
__SIGRTMIN + 67,
__SIGRTMIN + 68,
__SIGRTMIN + 69,
__SIGRTMIN + 70,
__SIGRTMIN + 71,
__SIGRTMIN + 72,
__SIGRTMIN + 73,
__SIGRTMIN + 74,
__SIGRTMIN + 75,
__SIGRTMIN + 76,
__SIGRTMIN + 77,
__SIGRTMIN + 78,
__SIGRTMIN + 79,
__SIGRTMIN + 80,
__SIGRTMIN + 81,
__SIGRTMIN + 82,
__SIGRTMIN + 83,
__SIGRTMIN + 84,
__SIGRTMIN + 85,
__SIGRTMIN + 86,
__SIGRTMIN + 87,
__SIGRTMIN + 88,
__SIGRTMIN + 89,
__SIGRTMIN + 90,
__SIGRTMIN + 91,
__SIGRTMIN + 92,
__SIGRTMIN + 93,
__SIGRTMIN + 94,
__SIGRTMIN + 95,
-1, /* SIGINFO */
-1, /* UNKNOWN */
-1, /* DEFAULT */
-1,
-1,
-1,
-1,
-1,
-1
#endif
};
#else
/* In system mode we only need SIGINT and SIGTRAP; other signals
are not yet supported. */
enum {
TARGET_SIGINT = 2,
TARGET_SIGTRAP = 5
};
static int gdb_signal_table[] = {
-1,
-1,
TARGET_SIGINT,
-1,
-1,
TARGET_SIGTRAP
};
#endif
#ifdef CONFIG_USER_ONLY
static int target_signal_to_gdb (int sig)
{
int i;
for (i = 0; i < ARRAY_SIZE (gdb_signal_table); i++)
if (gdb_signal_table[i] == sig)
return i;
return GDB_SIGNAL_UNKNOWN;
}
#endif
static int gdb_signal_to_target (int sig)
{
if (sig < ARRAY_SIZE (gdb_signal_table))
return gdb_signal_table[sig];
else
return -1;
}
typedef struct GDBRegisterState {
int base_reg;
int num_regs;
gdb_reg_cb get_reg;
gdb_reg_cb set_reg;
const char *xml;
struct GDBRegisterState *next;
} GDBRegisterState;
typedef struct GDBProcess {
uint32_t pid;
bool attached;
char target_xml[1024];
} GDBProcess;
enum RSState {
RS_INACTIVE,
RS_IDLE,
RS_GETLINE,
RS_GETLINE_ESC,
RS_GETLINE_RLE,
RS_CHKSUM1,
RS_CHKSUM2,
};
typedef struct GDBState {
CPUState *c_cpu; /* current CPU for step/continue ops */
CPUState *g_cpu; /* current CPU for other ops */
CPUState *query_cpu; /* for q{f|s}ThreadInfo */
enum RSState state; /* parsing state */
char line_buf[MAX_PACKET_LENGTH];
int line_buf_index;
int line_sum; /* running checksum */
int line_csum; /* checksum at the end of the packet */
uint8_t last_packet[MAX_PACKET_LENGTH + 4];
int last_packet_len;
int signal;
#ifdef CONFIG_USER_ONLY
int fd;
int running_state;
#else
CharBackend chr;
Chardev *mon_chr;
#endif
bool multiprocess;
GDBProcess *processes;
int process_num;
char syscall_buf[256];
gdb_syscall_complete_cb current_syscall_cb;
} GDBState;
/* By default use no IRQs and no timers while single stepping so as to
* make single stepping like an ICE HW step.
*/
static int sstep_flags = SSTEP_ENABLE|SSTEP_NOIRQ|SSTEP_NOTIMER;
static GDBState *gdbserver_state;
bool gdb_has_xml;
#ifdef CONFIG_USER_ONLY
/* XXX: This is not thread safe. Do we care? */
static int gdbserver_fd = -1;
static int get_char(GDBState *s)
{
uint8_t ch;
int ret;
for(;;) {
ret = qemu_recv(s->fd, &ch, 1, 0);
if (ret < 0) {
if (errno == ECONNRESET)
s->fd = -1;
if (errno != EINTR)
return -1;
} else if (ret == 0) {
close(s->fd);
s->fd = -1;
return -1;
} else {
break;
}
}
return ch;
}
#endif
static enum {
GDB_SYS_UNKNOWN,
GDB_SYS_ENABLED,
GDB_SYS_DISABLED,
} gdb_syscall_mode;
/* Decide if either remote gdb syscalls or native file IO should be used. */
int use_gdb_syscalls(void)
{
SemihostingTarget target = semihosting_get_target();
if (target == SEMIHOSTING_TARGET_NATIVE) {
/* -semihosting-config target=native */
return false;
} else if (target == SEMIHOSTING_TARGET_GDB) {
/* -semihosting-config target=gdb */
return true;
}
/* -semihosting-config target=auto */
/* On the first call check if gdb is connected and remember. */
if (gdb_syscall_mode == GDB_SYS_UNKNOWN) {
gdb_syscall_mode = (gdbserver_state ? GDB_SYS_ENABLED
: GDB_SYS_DISABLED);
}
return gdb_syscall_mode == GDB_SYS_ENABLED;
}
/* Resume execution. */
static inline void gdb_continue(GDBState *s)
{
#ifdef CONFIG_USER_ONLY
s->running_state = 1;
trace_gdbstub_op_continue();
#else
if (!runstate_needs_reset()) {
trace_gdbstub_op_continue();
vm_start();
}
#endif
}
/*
* Resume execution, per CPU actions. For user-mode emulation it's
* equivalent to gdb_continue.
*/
static int gdb_continue_partial(GDBState *s, char *newstates)
{
CPUState *cpu;
int res = 0;
#ifdef CONFIG_USER_ONLY
/*
* This is not exactly accurate, but it's an improvement compared to the
* previous situation, where only one CPU would be single-stepped.
*/
CPU_FOREACH(cpu) {
if (newstates[cpu->cpu_index] == 's') {
trace_gdbstub_op_stepping(cpu->cpu_index);
cpu_single_step(cpu, sstep_flags);
}
}
s->running_state = 1;
#else
int flag = 0;
if (!runstate_needs_reset()) {
if (vm_prepare_start()) {
return 0;
}
CPU_FOREACH(cpu) {
switch (newstates[cpu->cpu_index]) {
case 0:
case 1:
break; /* nothing to do here */
case 's':
trace_gdbstub_op_stepping(cpu->cpu_index);
cpu_single_step(cpu, sstep_flags);
cpu_resume(cpu);
flag = 1;
break;
case 'c':
trace_gdbstub_op_continue_cpu(cpu->cpu_index);
cpu_resume(cpu);
flag = 1;
break;
default:
res = -1;
break;
}
}
}
if (flag) {
qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
}
#endif
return res;
}
static void put_buffer(GDBState *s, const uint8_t *buf, int len)
{
#ifdef CONFIG_USER_ONLY
int ret;
while (len > 0) {
ret = send(s->fd, buf, len, 0);
if (ret < 0) {
if (errno != EINTR)
return;
} else {
buf += ret;
len -= ret;
}
}
#else
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_fe_write_all(&s->chr, buf, len);
#endif
}
static inline int fromhex(int v)
{
if (v >= '0' && v <= '9')
return v - '0';
else if (v >= 'A' && v <= 'F')
return v - 'A' + 10;
else if (v >= 'a' && v <= 'f')
return v - 'a' + 10;
else
return 0;
}
static inline int tohex(int v)
{
if (v < 10)
return v + '0';
else
return v - 10 + 'a';
}
/* writes 2*len+1 bytes in buf */
static void memtohex(char *buf, const uint8_t *mem, int len)
{
int i, c;
char *q;
q = buf;
for(i = 0; i < len; i++) {
c = mem[i];
*q++ = tohex(c >> 4);
*q++ = tohex(c & 0xf);
}
*q = '\0';
}
static void hextomem(uint8_t *mem, const char *buf, int len)
{
int i;
for(i = 0; i < len; i++) {
mem[i] = (fromhex(buf[0]) << 4) | fromhex(buf[1]);
buf += 2;
}
}
static void hexdump(const char *buf, int len,
void (*trace_fn)(size_t ofs, char const *text))
{
char line_buffer[3 * 16 + 4 + 16 + 1];
size_t i;
for (i = 0; i < len || (i & 0xF); ++i) {
size_t byte_ofs = i & 15;
if (byte_ofs == 0) {
memset(line_buffer, ' ', 3 * 16 + 4 + 16);
line_buffer[3 * 16 + 4 + 16] = 0;
}
size_t col_group = (i >> 2) & 3;
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