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author | 2009-06-03 11:33:08 -0700 | |
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committer | 2009-06-04 10:04:49 +0100 | |
commit | 1e9fa730163c2a445014ff8324b169cd82a50df1 (patch) | |
tree | 5d149df819dc4213b77c82ae7eb6249010d68ac3 /gdbstub.c | |
parent | CRIS: Remove duplicated flag defines. (diff) | |
download | qemu-kvm-1e9fa730163c2a445014ff8324b169cd82a50df1.tar.gz qemu-kvm-1e9fa730163c2a445014ff8324b169cd82a50df1.tar.bz2 qemu-kvm-1e9fa730163c2a445014ff8324b169cd82a50df1.zip |
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.c | 69 |
1 files changed, 44 insertions, 25 deletions
@@ -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 |