gdbstub: Implement gdb_do_syscallv()

Implement a variant of the existing gdb_do_syscall() which
takes a va_list.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Tested-by: NChristopher Covington <cov@codeaurora.org>
Message-id: 1439483745-28752-4-git-send-email-peter.maydell@linaro.org

gdbstub.c

@@ -1301,9 +1301,8 @@ send_packet:
     %x  - target_ulong argument printed in hex.
     %lx - 64-bit argument printed in hex.
     %s  - string pointer (target_ulong) and length (int) pair.  */
-void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
+void gdb_do_syscallv(gdb_syscall_complete_cb cb, const char *fmt, va_list va)
 {
-    va_list va;
     char *p;
     char *p_end;
     target_ulong addr;
@@ -1317,7 +1316,6 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
 #ifndef CONFIG_USER_ONLY
     vm_stop(RUN_STATE_DEBUG);
 #endif
-    va_start(va, fmt);
     p = s->syscall_buf;
     p_end = &s->syscall_buf[sizeof(s->syscall_buf)];
     *(p++) = 'F';
@@ -1351,7 +1349,6 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
         }
     }
     *p = 0;
-    va_end(va);
 #ifdef CONFIG_USER_ONLY
     put_packet(s, s->syscall_buf);
     gdb_handlesig(s->c_cpu, 0);
@@ -1366,6 +1363,15 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
 #endif
 }
 
+void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...)
+{
+    va_list va;
+
+    va_start(va, fmt);
+    gdb_do_syscallv(cb, fmt, va);
+    va_end(va);
+}
+
 static void gdb_read_byte(GDBState *s, int ch)
 {
     int i, csum;

include/exec/gdbstub.h

@@ -14,7 +14,34 @@
 typedef void (*gdb_syscall_complete_cb)(CPUState *cpu,
                                         target_ulong ret, target_ulong err);
 
+/**
+ * gdb_do_syscall:
+ * @cb: function to call when the system call has completed
+ * @fmt: gdb syscall format string
+ * ...: list of arguments to interpolate into @fmt
+ *
+ * Send a GDB syscall request. This function will return immediately;
+ * the callback function will be called later when the remote system
+ * call has completed.
+ *
+ * @fmt should be in the 'call-id,parameter,parameter...' format documented
+ * for the F request packet in the GDB remote protocol. A limited set of
+ * printf-style format specifiers is supported:
+ *   %x  - target_ulong argument printed in hex
+ *   %lx - 64-bit argument printed in hex
+ *   %s  - string pointer (target_ulong) and length (int) pair
+ */
 void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...);
+/**
+ * gdb_do_syscallv:
+ * @cb: function to call when the system call has completed
+ * @fmt: gdb syscall format string
+ * @va: arguments to interpolate into @fmt
+ *
+ * As gdb_do_syscall, but taking a va_list rather than a variable
+ * argument list.
+ */
+void gdb_do_syscallv(gdb_syscall_complete_cb cb, const char *fmt, va_list va);
 int use_gdb_syscalls(void);
 void gdb_set_stop_cpu(CPUState *cpu);
 void gdb_exit(CPUArchState *, int);