@@ -33,6 +33,7 @@
#include "qemu/guest-random.h"
#include "qemu/timer.h"
#include "exec/exec-all.h"
+#include "exec/gdbstub.h"
#include "exec/hwaddr.h"
#include "exec/tb-flush.h"
#include "gdbstub/enums.h"
@@ -137,9 +138,11 @@ static int tcg_insert_breakpoint(CPUState *cs, int type, vaddr addr, vaddr len)
case GDB_BREAKPOINT_SW:
case GDB_BREAKPOINT_HW:
CPU_FOREACH(cpu) {
- err = cpu_breakpoint_insert(cpu, addr, BP_GDB, NULL);
- if (err) {
- break;
+ if (gdb_cpu_in_source_group(cs, cpu)) {
+ err = cpu_breakpoint_insert(cpu, addr, BP_GDB, NULL);
+ if (err) {
+ break;
+ }
}
}
return err;
@@ -147,10 +150,12 @@ static int tcg_insert_breakpoint(CPUState *cs, int type, vaddr addr, vaddr len)
case GDB_WATCHPOINT_READ:
case GDB_WATCHPOINT_ACCESS:
CPU_FOREACH(cpu) {
- err = cpu_watchpoint_insert(cpu, addr, len,
- xlat_gdb_type(cpu, type), NULL);
- if (err) {
- break;
+ if (gdb_cpu_in_source_group(cs, cpu)) {
+ err = cpu_watchpoint_insert(cpu, addr, len,
+ xlat_gdb_type(cpu, type), NULL);
+ if (err) {
+ break;
+ }
}
}
return err;
@@ -168,9 +173,11 @@ static int tcg_remove_breakpoint(CPUState *cs, int type, vaddr addr, vaddr len)
case GDB_BREAKPOINT_SW:
case GDB_BREAKPOINT_HW:
CPU_FOREACH(cpu) {
- err = cpu_breakpoint_remove(cpu, addr, BP_GDB);
- if (err) {
- break;
+ if (gdb_cpu_in_source_group(cs, cpu)) {
+ err = cpu_breakpoint_remove(cpu, addr, BP_GDB);
+ if (err) {
+ break;
+ }
}
}
return err;
@@ -178,10 +185,12 @@ static int tcg_remove_breakpoint(CPUState *cs, int type, vaddr addr, vaddr len)
case GDB_WATCHPOINT_READ:
case GDB_WATCHPOINT_ACCESS:
CPU_FOREACH(cpu) {
- err = cpu_watchpoint_remove(cpu, addr, len,
- xlat_gdb_type(cpu, type));
- if (err) {
- break;
+ if (gdb_cpu_in_source_group(cs, cpu)) {
+ err = cpu_watchpoint_remove(cpu, addr, len,
+ xlat_gdb_type(cpu, type));
+ if (err) {
+ break;
+ }
}
}
return err;
@@ -493,6 +493,12 @@ const GDBFeature *gdb_find_static_feature(const char *xmlname)
g_assert_not_reached();
}
+bool gdb_cpu_in_source_group(CPUState *cs, CPUState *cpu)
+{
+ return !gdbserver_state.multiprocess ||
+ (gdb_get_cpu_pid(cs) == gdb_get_cpu_pid(cpu));
+}
+
GArray *gdb_get_register_list(CPUState *cpu)
{
GArray *results = g_array_new(true, true, sizeof(GDBRegDesc));
@@ -108,6 +108,18 @@ void gdb_feature_builder_end(const GDBFeatureBuilder *builder);
*/
const GDBFeature *gdb_find_static_feature(const char *xmlname);
+/**
+ * Tests if the CPUs belong to the same group for the purposes of breakpoint
+ * insertion and deletion when running multiprocesses gdb. The test is only
+ * valid for multiprocess gdb and should not affect the insertion or deletion of
+ * breakpoints when we are not running in that mode.
+ * @cs: The CPU used as reference
+ * @cpu: The CPU to test
+ *
+ * Return: True if they belong to the same group or it is not a multiprocess gdb
+ */
+bool gdb_cpu_in_source_group(CPUState *cs, CPUState *cpu);
+
/**
* gdb_read_register() - Read a register associated with a CPU.
* @cpu: The CPU associated with the register.
In the context of using the remote gdb with multiple processes/inferiors (multi cluster machine) a given breakpoint will target an specific inferior. Current implementation of tcg_insert_breakpoint and tcg_remove_breakpoint apply a given breakpoint to all the cpus available in the system. This is not how gdb expects the remote protocol to behave. If we refer to the current source of gdb, in the function remote_target::insert_breakpoint in the file gdb/remote.c we can see the intention to have the right process selected before breakpoint insertion: int remote_target::insert_breakpoint (struct gdbarch *gdbarch, struct bp_target_info *bp_tgt) { ... /* Make sure the remote is pointing at the right process, if necessary. */ if (!gdbarch_has_global_breakpoints (current_inferior ()->arch ())) set_general_process (); ... } Since most platforms do not have global breakpoints, this typically will result in an 'Hg' Packet sent before 'z/Z', if gdb is not pointing to the desired process. For instance this is a concrete example obtained with a trace dump: gdbstub_io_command Received: Hgp2.2 gdbstub_io_command Received: Z0,4000ded0,4 Only the CPUs associated with the selected process ID should insert or remove the breakpoint. It is important to apply it to all the CPUs in the process ID regardless of the particular thread selected by the 'Hg' packet because even in the case of a thread specific breakpoint. A breakpoint on a specific thread is treated as a conditional break similar to a 'break if'. This can be read in the code and comments of function bpstat_check_breakpoint_conditions in the file gdb/breakpoint.c /* For breakpoints that are currently marked as telling gdb to stop, check conditions (condition proper, frame, thread and ignore count) of breakpoint referred to by BS. If we should not stop for this breakpoint, set BS->stop to 0. */ static void bpstat_check_breakpoint_conditions (bpstat *bs, thread_info *thread) The patch creates a function to identify the CPUs that should be affected by the breakpoint insertion/deletion operations based on the thread-id sent in the last 'Hg' packet. When multiprocess gdb is not used it falls back to applying the breakpoints to all cpus. Signed-off-by: Roque Arcudia Hernandez <roqueh@google.com> --- accel/tcg/tcg-accel-ops.c | 37 +++++++++++++++++++++++-------------- gdbstub/gdbstub.c | 6 ++++++ include/exec/gdbstub.h | 12 ++++++++++++ 3 files changed, 41 insertions(+), 14 deletions(-)