gdbstub: split out softmmu/user specifics for syscall handling

Most of the syscall code is config agnostic aside from the size of
target_ulong. In preparation for the next patch move the final bits
of specialisation into the appropriate user and softmmu helpers.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230302190846.2593720-26-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-26-richard.henderson@linaro.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/gdbstub/softmmu.c b/gdbstub/softmmu.c
index d3152fb6e7..22ecd09d04 100644
--- a/gdbstub/softmmu.c
+++ b/gdbstub/softmmu.c
@@ -103,6 +103,20 @@ static void gdb_chr_event(void *opaque, QEMUChrEvent event)
     }
 }
 
+/*
+ * In softmmu mode we stop the VM and wait to send the syscall packet
+ * until notification that the CPU has stopped. This must be done
+ * because if the packet is sent now the reply from the syscall
+ * request could be received while the CPU is still in the running
+ * state, which can cause packets to be dropped and state transition
+ * 'T' packets to be sent while the syscall is still being processed.
+ */
+void gdb_syscall_handling(const char *syscall_packet)
+{
+    vm_stop(RUN_STATE_DEBUG);
+    qemu_cpu_kick(gdbserver_state.c_cpu);
+}
+
 static void gdb_vm_state_change(void *opaque, bool running, RunState state)
 {
     CPUState *cpu = gdbserver_state.c_cpu;