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authorNathan Froyd <froydnj@codesourcery.com>2009-06-03 11:33:08 -0700
committerPaul Brook <paul@codesourcery.com>2009-06-04 10:04:49 +0100
commit1e9fa730163c2a445014ff8324b169cd82a50df1 (patch)
tree5d149df819dc4213b77c82ae7eb6249010d68ac3 /gdbstub.c
parentCRIS: Remove duplicated flag defines. (diff)
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fix gdbstub support for multiple threads in usermode, v3
When debugging multi-threaded programs, QEMU's gdb stub would report the correct number of threads (the qfThreadInfo and qsThreadInfo packets). However, the stub was unable to actually switch between threads (the T packet), since it would report every thread except the first as being dead. Furthermore, the stub relied upon cpu_index as a reliable means of assigning IDs to the threads. This was a bad idea; if you have this sequence of events: initial thread created new thread #1 new thread #2 thread #1 exits new thread #3 thread #3 will have the same cpu_index as thread #1, which would confuse GDB. (This problem is partly due to the remote protocol not having a good way to send thread creation/destruction events.) We fix this by using the host thread ID for the identifier passed to GDB when debugging a multi-threaded userspace program. The thread ID might wrap, but the same sort of problems with wrapping thread IDs would come up with debugging programs natively, so this doesn't represent a problem. Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Diffstat (limited to 'gdbstub.c')
-rw-r--r--gdbstub.c69
1 files changed, 44 insertions, 25 deletions
diff --git a/gdbstub.c b/gdbstub.c
index 7b32fab58..9bd437585 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1567,11 +1567,34 @@ static void gdb_set_cpu_pc(GDBState *s, target_ulong pc)
#endif
}
+static inline int gdb_id(CPUState *env)
+{
+#if defined(CONFIG_USER_ONLY) && defined(USE_NPTL)
+ return env->host_tid;
+#else
+ return env->cpu_index + 1;
+#endif
+}
+
+static CPUState *find_cpu(uint32_t thread_id)
+{
+ CPUState *env;
+
+ for (env = first_cpu; env != NULL; env = env->next_cpu) {
+ if (gdb_id(env) == thread_id) {
+ return env;
+ }
+ }
+
+ return NULL;
+}
+
static int gdb_handle_packet(GDBState *s, const char *line_buf)
{
CPUState *env;
const char *p;
- int ch, reg_size, type, res, thread;
+ uint32_t thread;
+ int ch, reg_size, type, res;
char buf[MAX_PACKET_LENGTH];
uint8_t mem_buf[MAX_PACKET_LENGTH];
uint8_t *registers;
@@ -1586,7 +1609,7 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
case '?':
/* TODO: Make this return the correct value for user-mode. */
snprintf(buf, sizeof(buf), "T%02xthread:%02x;", GDB_SIGNAL_TRAP,
- s->c_cpu->cpu_index+1);
+ gdb_id(s->c_cpu));
put_packet(s, buf);
/* Remove all the breakpoints when this query is issued,
* because gdb is doing and initial connect and the state
@@ -1750,9 +1773,7 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
put_packet(s, "OK");
break;
}
- for (env = first_cpu; env != NULL; env = env->next_cpu)
- if (env->cpu_index + 1 == thread)
- break;
+ env = find_cpu(thread);
if (env == NULL) {
put_packet(s, "E22");
break;
@@ -1773,14 +1794,13 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
break;
case 'T':
thread = strtoull(p, (char **)&p, 16);
-#ifndef CONFIG_USER_ONLY
- if (thread > 0 && thread < smp_cpus + 1)
-#else
- if (thread == 1)
-#endif
- put_packet(s, "OK");
- else
+ env = find_cpu(thread);
+
+ if (env != NULL) {
+ put_packet(s, "OK");
+ } else {
put_packet(s, "E22");
+ }
break;
case 'q':
case 'Q':
@@ -1818,7 +1838,7 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
} else if (strcmp(p,"sThreadInfo") == 0) {
report_cpuinfo:
if (s->query_cpu) {
- snprintf(buf, sizeof(buf), "m%x", s->query_cpu->cpu_index+1);
+ snprintf(buf, sizeof(buf), "m%x", gdb_id(s->query_cpu));
put_packet(s, buf);
s->query_cpu = s->query_cpu->next_cpu;
} else
@@ -1826,16 +1846,15 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
break;
} else if (strncmp(p,"ThreadExtraInfo,", 16) == 0) {
thread = strtoull(p+16, (char **)&p, 16);
- for (env = first_cpu; env != NULL; env = env->next_cpu)
- if (env->cpu_index + 1 == thread) {
- cpu_synchronize_state(env, 0);
- len = snprintf((char *)mem_buf, sizeof(mem_buf),
- "CPU#%d [%s]", env->cpu_index,
- env->halted ? "halted " : "running");
- memtohex(buf, mem_buf, len);
- put_packet(s, buf);
- break;
- }
+ env = find_cpu(thread);
+ if (env != NULL) {
+ cpu_synchronize_state(env, 0);
+ len = snprintf((char *)mem_buf, sizeof(mem_buf),
+ "CPU#%d [%s]", env->cpu_index,
+ env->halted ? "halted " : "running");
+ memtohex(buf, mem_buf, len);
+ put_packet(s, buf);
+ }
break;
}
#ifdef CONFIG_USER_ONLY
@@ -1965,7 +1984,7 @@ static void gdb_vm_state_change(void *opaque, int running, int reason)
}
snprintf(buf, sizeof(buf),
"T%02xthread:%02x;%swatch:" TARGET_FMT_lx ";",
- GDB_SIGNAL_TRAP, env->cpu_index+1, type,
+ GDB_SIGNAL_TRAP, gdb_id(env), type,
env->watchpoint_hit->vaddr);
put_packet(s, buf);
env->watchpoint_hit = NULL;
@@ -1976,7 +1995,7 @@ static void gdb_vm_state_change(void *opaque, int running, int reason)
} else {
ret = GDB_SIGNAL_INT;
}
- snprintf(buf, sizeof(buf), "T%02xthread:%02x;", ret, env->cpu_index+1);
+ snprintf(buf, sizeof(buf), "T%02xthread:%02x;", ret, gdb_id(env));
put_packet(s, buf);
}
#endif