[v4] gdbstub: add tracing

Message ID 20171203013037.31978-1-doug16k@gmail.com
State New
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Series
  • [v4] gdbstub: add tracing
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Commit Message

Doug Gale Dec. 3, 2017, 1:30 a.m.
Signed-off-by: Doug Gale <doug16k@gmail.com>
---
Fix usage of %c in trace output, now uses 0x%02x
Fix possible sign extended char that could cause 0xfc to say 0xfffffffc
Add missing traces for hitting breakpoints, continuing, stepping
Fix incorrect dynamic check for tracing being enabled in hexdump
Fix missing braces around single line if body
Fix incorrectly indented return statement
Fix order of trace-events to be more tidy
 gdbstub.c    | 113 +++++++++++++++++++++++++++++++++++++++++------------------
 trace-events |  28 +++++++++++++++
 2 files changed, 106 insertions(+), 35 deletions(-)

Comments

Stefan Hajnoczi Dec. 5, 2017, 2 p.m. | #1
On Sat, Dec 02, 2017 at 08:30:37PM -0500, Doug Gale wrote:
> Signed-off-by: Doug Gale <doug16k@gmail.com>
> ---
> Fix usage of %c in trace output, now uses 0x%02x
> Fix possible sign extended char that could cause 0xfc to say 0xfffffffc
> Add missing traces for hitting breakpoints, continuing, stepping
> Fix incorrect dynamic check for tracing being enabled in hexdump
> Fix missing braces around single line if body
> Fix incorrectly indented return statement
> Fix order of trace-events to be more tidy
>  gdbstub.c    | 113 +++++++++++++++++++++++++++++++++++++++++------------------
>  trace-events |  28 +++++++++++++++
>  2 files changed, 106 insertions(+), 35 deletions(-)

Thanks, since there is no gdbstub.c maintainer I have applied this to my
tracing-next tree:
https://github.com/stefanha/qemu/commits/tracing-next

Stefan

Patch

diff --git a/gdbstub.c b/gdbstub.c
index 2a94030d3b..f1d51480f7 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -21,6 +21,7 @@ 
 #include "qemu/error-report.h"
 #include "qemu/cutils.h"
 #include "cpu.h"
+#include "trace-root.h"
 #ifdef CONFIG_USER_ONLY
 #include "qemu.h"
 #else
@@ -287,21 +288,6 @@  static int gdb_signal_to_target (int sig)
         return -1;
 }
 
-/* #define DEBUG_GDB */
-
-#ifdef DEBUG_GDB
-# define DEBUG_GDB_GATE 1
-#else
-# define DEBUG_GDB_GATE 0
-#endif
-
-#define gdb_debug(fmt, ...) do { \
-    if (DEBUG_GDB_GATE) { \
-        fprintf(stderr, "%s: " fmt, __func__, ## __VA_ARGS__); \
-    } \
-} while (0)
-
-
 typedef struct GDBRegisterState {
     int base_reg;
     int num_regs;
@@ -410,10 +396,13 @@  int use_gdb_syscalls(void)
 /* 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
@@ -434,6 +423,7 @@  static int gdb_continue_partial(GDBState *s, char *newstates)
      */
     CPU_FOREACH(cpu) {
         if (newstates[cpu->cpu_index] == 's') {
+            trace_gdbstub_op_stepping(cpu->cpu_index);
             cpu_single_step(cpu, sstep_flags);
         }
     }
@@ -452,11 +442,13 @@  static int gdb_continue_partial(GDBState *s, char *newstates)
             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;
@@ -538,12 +530,49 @@  static void hextomem(uint8_t *mem, const char *buf, int len)
     }
 }
 
+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;
+        size_t hex_col = byte_ofs * 3 + col_group;
+        size_t txt_col = 3 * 16 + 4 + byte_ofs;
+
+        if (i < len) {
+            char value = buf[i];
+
+            line_buffer[hex_col + 0] = tohex((value >> 4) & 0xF);
+            line_buffer[hex_col + 1] = tohex((value >> 0) & 0xF);
+            line_buffer[txt_col + 0] = (value >= ' ' && value < 127)
+                    ? value
+                    : '.';
+        }
+
+        if (byte_ofs == 0xF)
+            trace_fn(i & -16, line_buffer);
+    }
+}
+
 /* return -1 if error, 0 if OK */
-static int put_packet_binary(GDBState *s, const char *buf, int len)
+static int put_packet_binary(GDBState *s, const char *buf, int len, bool dump)
 {
     int csum, i;
     uint8_t *p;
 
+    if (dump && trace_event_get_state_backends(TRACE_GDBSTUB_IO_BINARYREPLY)) {
+        hexdump(buf, len, trace_gdbstub_io_binaryreply);
+    }
+
     for(;;) {
         p = s->last_packet;
         *(p++) = '$';
@@ -576,9 +605,9 @@  static int put_packet_binary(GDBState *s, const char *buf, int len)
 /* return -1 if error, 0 if OK */
 static int put_packet(GDBState *s, const char *buf)
 {
-    gdb_debug("reply='%s'\n", buf);
+    trace_gdbstub_io_reply(buf);
 
-    return put_packet_binary(s, buf, strlen(buf));
+    return put_packet_binary(s, buf, strlen(buf), false);
 }
 
 /* Encode data using the encoding for 'x' packets.  */
@@ -975,8 +1004,7 @@  static int gdb_handle_packet(GDBState *s, const char *line_buf)
     uint8_t *registers;
     target_ulong addr, len;
 
-
-    gdb_debug("command='%s'\n", line_buf);
+    trace_gdbstub_io_command(line_buf);
 
     p = line_buf;
     ch = *p++;
@@ -999,7 +1027,7 @@  static int gdb_handle_packet(GDBState *s, const char *line_buf)
         }
         s->signal = 0;
         gdb_continue(s);
-	return RS_IDLE;
+        return RS_IDLE;
     case 'C':
         s->signal = gdb_signal_to_target (strtoul(p, (char **)&p, 16));
         if (s->signal == -1)
@@ -1045,7 +1073,7 @@  static int gdb_handle_packet(GDBState *s, const char *line_buf)
         }
         cpu_single_step(s->c_cpu, sstep_flags);
         gdb_continue(s);
-	return RS_IDLE;
+        return RS_IDLE;
     case 'F':
         {
             target_ulong ret;
@@ -1267,6 +1295,7 @@  static int gdb_handle_packet(GDBState *s, const char *line_buf)
                 len = snprintf((char *)mem_buf, sizeof(buf) / 2,
                                "CPU#%d [%s]", cpu->cpu_index,
                                cpu->halted ? "halted " : "running");
+                trace_gdbstub_op_extra_info((char *)mem_buf);
                 memtohex(buf, mem_buf, len);
                 put_packet(s, buf);
             }
@@ -1350,7 +1379,7 @@  static int gdb_handle_packet(GDBState *s, const char *line_buf)
                 buf[0] = 'l';
                 len = memtox(buf + 1, xml + addr, total_len - addr);
             }
-            put_packet_binary(s, buf, len + 1);
+            put_packet_binary(s, buf, len + 1, true);
             break;
         }
         if (is_query_packet(p, "Attached", ':')) {
@@ -1407,29 +1436,38 @@  static void gdb_vm_state_change(void *opaque, int running, RunState state)
                 type = "";
                 break;
             }
+            trace_gdbstub_hit_watchpoint(type, cpu_gdb_index(cpu),
+                    (target_ulong)cpu->watchpoint_hit->vaddr);
             snprintf(buf, sizeof(buf),
                      "T%02xthread:%02x;%swatch:" TARGET_FMT_lx ";",
                      GDB_SIGNAL_TRAP, cpu_gdb_index(cpu), type,
                      (target_ulong)cpu->watchpoint_hit->vaddr);
             cpu->watchpoint_hit = NULL;
             goto send_packet;
+        } else {
+            trace_gdbstub_hit_break();
         }
         tb_flush(cpu);
         ret = GDB_SIGNAL_TRAP;
         break;
     case RUN_STATE_PAUSED:
+        trace_gdbstub_hit_paused();
         ret = GDB_SIGNAL_INT;
         break;
     case RUN_STATE_SHUTDOWN:
+        trace_gdbstub_hit_shutdown();
         ret = GDB_SIGNAL_QUIT;
         break;
     case RUN_STATE_IO_ERROR:
+        trace_gdbstub_hit_io_error();
         ret = GDB_SIGNAL_IO;
         break;
     case RUN_STATE_WATCHDOG:
+        trace_gdbstub_hit_watchdog();
         ret = GDB_SIGNAL_ALRM;
         break;
     case RUN_STATE_INTERNAL_ERROR:
+        trace_gdbstub_hit_internal_error();
         ret = GDB_SIGNAL_ABRT;
         break;
     case RUN_STATE_SAVE_VM:
@@ -1439,6 +1477,7 @@  static void gdb_vm_state_change(void *opaque, int running, RunState state)
         ret = GDB_SIGNAL_XCPU;
         break;
     default:
+        trace_gdbstub_hit_unknown(state);
         ret = GDB_SIGNAL_UNKNOWN;
         break;
     }
@@ -1538,12 +1577,12 @@  static void gdb_read_byte(GDBState *s, int ch)
         /* Waiting for a response to the last packet.  If we see the start
            of a new command then abandon the previous response.  */
         if (ch == '-') {
-            gdb_debug("Got NACK, retransmitting\n");
+            trace_gdbstub_err_got_nack();
             put_buffer(s, (uint8_t *)s->last_packet, s->last_packet_len);
         } else if (ch == '+') {
-            gdb_debug("Got ACK\n");
+            trace_gdbstub_io_got_ack();
         } else {
-            gdb_debug("Got '%c' when expecting ACK/NACK\n", ch);
+            trace_gdbstub_io_got_unexpected((uint8_t)ch);
         }
 
         if (ch == '+' || ch == '$')
@@ -1566,7 +1605,7 @@  static void gdb_read_byte(GDBState *s, int ch)
                 s->line_sum = 0;
                 s->state = RS_GETLINE;
             } else {
-                gdb_debug("received garbage between packets: 0x%x\n", ch);
+                trace_gdbstub_err_garbage((uint8_t)ch);
             }
             break;
         case RS_GETLINE:
@@ -1582,7 +1621,7 @@  static void gdb_read_byte(GDBState *s, int ch)
                 /* end of command, start of checksum*/
                 s->state = RS_CHKSUM1;
             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
-                gdb_debug("command buffer overrun, dropping command\n");
+                trace_gdbstub_err_overrun();
                 s->state = RS_IDLE;
             } else {
                 /* unescaped command character */
@@ -1596,7 +1635,7 @@  static void gdb_read_byte(GDBState *s, int ch)
                 s->state = RS_CHKSUM1;
             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
                 /* command buffer overrun */
-                gdb_debug("command buffer overrun, dropping command\n");
+                trace_gdbstub_err_overrun();
                 s->state = RS_IDLE;
             } else {
                 /* parse escaped character and leave escape state */
@@ -1608,18 +1647,18 @@  static void gdb_read_byte(GDBState *s, int ch)
         case RS_GETLINE_RLE:
             if (ch < ' ') {
                 /* invalid RLE count encoding */
-                gdb_debug("got invalid RLE count: 0x%x\n", ch);
+                trace_gdbstub_err_invalid_repeat((uint8_t)ch);
                 s->state = RS_GETLINE;
             } else {
                 /* decode repeat length */
                 int repeat = (unsigned char)ch - ' ' + 3;
                 if (s->line_buf_index + repeat >= sizeof(s->line_buf) - 1) {
                     /* that many repeats would overrun the command buffer */
-                    gdb_debug("command buffer overrun, dropping command\n");
+                    trace_gdbstub_err_overrun();
                     s->state = RS_IDLE;
                 } else if (s->line_buf_index < 1) {
                     /* got a repeat but we have nothing to repeat */
-                    gdb_debug("got invalid RLE sequence\n");
+                    trace_gdbstub_err_invalid_rle();
                     s->state = RS_GETLINE;
                 } else {
                     /* repeat the last character */
@@ -1634,7 +1673,7 @@  static void gdb_read_byte(GDBState *s, int ch)
         case RS_CHKSUM1:
             /* get high hex digit of checksum */
             if (!isxdigit(ch)) {
-                gdb_debug("got invalid command checksum digit\n");
+                trace_gdbstub_err_checksum_invalid((uint8_t)ch);
                 s->state = RS_GETLINE;
                 break;
             }
@@ -1645,14 +1684,14 @@  static void gdb_read_byte(GDBState *s, int ch)
         case RS_CHKSUM2:
             /* get low hex digit of checksum */
             if (!isxdigit(ch)) {
-                gdb_debug("got invalid command checksum digit\n");
+                trace_gdbstub_err_checksum_invalid((uint8_t)ch);
                 s->state = RS_GETLINE;
                 break;
             }
             s->line_csum |= fromhex(ch);
 
             if (s->line_csum != (s->line_sum & 0xff)) {
-                gdb_debug("got command packet with incorrect checksum\n");
+                trace_gdbstub_err_checksum_incorrect(s->line_sum, s->line_csum);
                 /* send NAK reply */
                 reply = '-';
                 put_buffer(s, &reply, 1);
@@ -1686,6 +1725,8 @@  void gdb_exit(CPUArchState *env, int code)
   }
 #endif
 
+  trace_gdbstub_op_exiting((uint8_t)code);
+
   snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
   put_packet(s, buf);
 
@@ -1944,6 +1985,8 @@  static const TypeInfo char_gdb_type_info = {
 
 int gdbserver_start(const char *device)
 {
+    trace_gdbstub_op_start(device);
+
     GDBState *s;
     char gdbstub_device_name[128];
     Chardev *chr = NULL;
diff --git a/trace-events b/trace-events
index 1d2eb5d3e4..3695959d0a 100644
--- a/trace-events
+++ b/trace-events
@@ -68,6 +68,34 @@  flatview_new(FlatView *view, MemoryRegion *root) "%p (root %p)"
 flatview_destroy(FlatView *view, MemoryRegion *root) "%p (root %p)"
 flatview_destroy_rcu(FlatView *view, MemoryRegion *root) "%p (root %p)"
 
+# gdbstub.c
+gdbstub_op_start(char const *device) "Starting gdbstub using device %s"
+gdbstub_op_exiting(uint8_t code) "notifying exit with code=0x%02x"
+gdbstub_op_continue(void) "Continuing all CPUs"
+gdbstub_op_continue_cpu(int cpu_index) "Continuing CPU %d"
+gdbstub_op_stepping(int cpu_index) "Stepping CPU %d"
+gdbstub_op_extra_info(char const *info) "Thread extra info: %s"
+gdbstub_hit_watchpoint(char const *type, int cpu_gdb_index, uint64_t vaddr) "Watchpoint hit, type=\"%s\" cpu=%d, vaddr=0x%" PRIx64 ""
+gdbstub_hit_internal_error(void) "RUN_STATE_INTERNAL_ERROR"
+gdbstub_hit_break(void) "RUN_STATE_DEBUG"
+gdbstub_hit_paused(void) "RUN_STATE_PAUSED"
+gdbstub_hit_shutdown(void) "RUN_STATE_SHUTDOWN"
+gdbstub_hit_io_error(void) "RUN_STATE_IO_ERROR"
+gdbstub_hit_watchdog(void) "RUN_STATE_WATCHDOG"
+gdbstub_hit_unknown(int state) "Unknown run state=0x%x"
+gdbstub_io_reply(char const *message) "Sent: %s"
+gdbstub_io_binaryreply(size_t ofs, char const *line) "0x%04zx: %s"
+gdbstub_io_command(char const *command) "Received: %s"
+gdbstub_io_got_ack(void) "Got ACK"
+gdbstub_io_got_unexpected(uint8_t ch) "Got 0x%02x when expecting ACK/NACK"
+gdbstub_err_got_nack(void) "Got NACK, retransmitting"
+gdbstub_err_garbage(uint8_t ch) "received garbage between packets: 0x%02x"
+gdbstub_err_overrun(void) "command buffer overrun, dropping command"
+gdbstub_err_invalid_repeat(uint8_t ch) "got invalid RLE count: 0x%02x"
+gdbstub_err_invalid_rle(void) "got invalid RLE sequence"
+gdbstub_err_checksum_invalid(uint8_t ch) "got invalid command checksum digit: 0x%02x"
+gdbstub_err_checksum_incorrect(uint8_t expected, uint8_t got) "got command packet with incorrect checksum, expected=0x%02x, received=0x%02x"
+
 ### Guest events, keep at bottom