gdbstub: Change gdbserver_fork() to accept cpu instead of env

All callsites to this function navigate the cpu->env_ptr only for the
function to take the env ptr back to the original cpu ptr. Change the
function to just pass in the CPU pointer instead. Removes a core code
usage of ENV_GET_CPU() (in gdbstub.c).

Cc: Riku Voipio <riku.voipio@iki.fi>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

bsd-user/main.c

@@ -92,7 +92,7 @@ void fork_start(void)
 void fork_end(int child)
 {
     if (child) {
-        gdbserver_fork((CPUArchState *)thread_cpu->env_ptr);
+        gdbserver_fork(thread_cpu);
     }
 }
 

gdbstub.c

@@ -1629,9 +1629,8 @@ int gdbserver_start(int port)
 }
 
 /* Disable gdb stub for child processes.  */
-void gdbserver_fork(CPUArchState *env)
+void gdbserver_fork(CPUState *cpu)
 {
-    CPUState *cpu = ENV_GET_CPU(env);
     GDBState *s = gdbserver_state;
 
     if (gdbserver_fd < 0 || s->fd < 0) {

include/exec/gdbstub.h

@@ -22,7 +22,7 @@ void gdb_exit(CPUArchState *, int);
 int gdb_queuesig (void);
 int gdb_handlesig(CPUState *, int);
 void gdb_signalled(CPUArchState *, int);
-void gdbserver_fork(CPUArchState *);
+void gdbserver_fork(CPUState *);
 #endif
 /* Get or set a register.  Returns the size of the register.  */
 typedef int (*gdb_reg_cb)(CPUArchState *env, uint8_t *buf, int reg);

linux-user/main.c

@@ -130,7 +130,7 @@ void fork_end(int child)
         pthread_cond_init(&exclusive_cond, NULL);
         pthread_cond_init(&exclusive_resume, NULL);
         pthread_mutex_init(&tcg_ctx.tb_ctx.tb_lock, NULL);
-        gdbserver_fork((CPUArchState *)thread_cpu->env_ptr);
+        gdbserver_fork(thread_cpu);
     } else {
         pthread_mutex_unlock(&exclusive_lock);
         pthread_mutex_unlock(&tcg_ctx.tb_ctx.tb_lock);