Merge remote-tracking branch 'remotes/kraxel/tags/vga-20191220-pull-request' into...

[qemu.git] / gdbstub.c

diff --git a/gdbstub.c b/gdbstub.c
index 687c02e598a81ee3040ceb4e74e8a0dc4fbc9c6f..4cf8af365e213b60b1bd5053a80d1d8205b7e8bd 100644 (file)
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1,6 +1,10 @@
 /*
  * gdb server stub
  *
+ * This implements a subset of the remote protocol as described in:
+ *
+ *   https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
+ *
  * Copyright (c) 2003-2005 Fabrice Bellard
  *
  * This library is free software; you can redistribute it and/or
@@ -15,6 +19,8 @@
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-2.0+
  */
 
 #include "qemu/osdep.h"
@@ -42,6 +48,7 @@
 #include "qemu/sockets.h"
 #include "sysemu/hw_accel.h"
 #include "sysemu/kvm.h"
+#include "sysemu/runstate.h"
 #include "hw/semihosting/semihost.h"
 #include "exec/exec-all.h"
 
@@ -1667,12 +1674,23 @@ static void handle_remove_bp(GdbCmdContext *gdb_ctx, void *user_ctx)
     put_packet(gdb_ctx->s, "E22");
 }
 
+/*
+ * handle_set/get_reg
+ *
+ * Older gdb are really dumb, and don't use 'G/g' if 'P/p' is available.
+ * This works, but can be very slow. Anything new enough to understand
+ * XML also knows how to use this properly. However to use this we
+ * need to define a local XML file as well as be talking to a
+ * reasonably modern gdb. Responding with an empty packet will cause
+ * the remote gdb to fallback to older methods.
+ */
+
 static void handle_set_reg(GdbCmdContext *gdb_ctx, void *user_ctx)
 {
     int reg_size;
 
     if (!gdb_has_xml) {
-        put_packet(gdb_ctx->s, "E00");
+        put_packet(gdb_ctx->s, "");
         return;
     }
 
@@ -1692,11 +1710,6 @@ static void handle_get_reg(GdbCmdContext *gdb_ctx, void *user_ctx)
 {
     int reg_size;
 
-    /*
-     * Older gdb are really dumb, and don't use 'g' if 'p' is avaialable.
-     * This works, but can be very slow.  Anything new enough to
-     * understand XML also knows how to use this properly.
-     */
     if (!gdb_has_xml) {
         put_packet(gdb_ctx->s, "");
         return;
@@ -1807,11 +1820,15 @@ static void handle_read_all_regs(GdbCmdContext *gdb_ctx, void *user_ctx)
 
 static void handle_file_io(GdbCmdContext *gdb_ctx, void *user_ctx)
 {
-    if (gdb_ctx->num_params >= 2 && gdb_ctx->s->current_syscall_cb) {
+    if (gdb_ctx->num_params >= 1 && gdb_ctx->s->current_syscall_cb) {
         target_ulong ret, err;
 
         ret = (target_ulong)gdb_ctx->params[0].val_ull;
-        err = (target_ulong)gdb_ctx->params[1].val_ull;
+        if (gdb_ctx->num_params >= 2) {
+            err = (target_ulong)gdb_ctx->params[1].val_ull;
+        } else {
+            err = 0;
+        }
         gdb_ctx->s->current_syscall_cb(gdb_ctx->s->c_cpu, ret, err);
         gdb_ctx->s->current_syscall_cb = NULL;
     }
@@ -2575,7 +2592,9 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
         break;
     }
 
-    run_cmd_parser(s, line_buf, cmd_parser);
+    if (cmd_parser) {
+        run_cmd_parser(s, line_buf, cmd_parser);
+    }
 
     return RS_IDLE;
 }