target/xtensa: gdbstub fix register counting

In order to communicate correctly with gdb xtensa gdbstub must provide
expected number of registers in 'g' packet response. xtensa-elf-gdb
expects both nonprivileged and privileged registers. xtensa-linux-gdb
only expects nonprivileged registers. gdb only counts one contiguous
stretch of registers, do the same for the core registers in the
xtensa_count_regs.

With this change qemu-system-xtensa is able to communicate with all
xtensa-elf-gdb versions (versions prior to 8.2 require overlay fixup),
and qemu-xtensa is able to communicate with all xtensa-linux-gdb
versions, except 8.2.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/target/xtensa/gdbstub.c b/target/xtensa/gdbstub.c
index c9450914c7..d43bb190c6 100644
--- a/target/xtensa/gdbstub.c
+++ b/target/xtensa/gdbstub.c
@@ -45,15 +45,20 @@ void xtensa_count_regs(const XtensaConfig *config,
                        unsigned *n_regs, unsigned *n_core_regs)
 {
     unsigned i;
+    bool count_core_regs = true;
 
     for (i = 0; config->gdb_regmap.reg[i].targno >= 0; ++i) {
         if (config->gdb_regmap.reg[i].type != xtRegisterTypeTieState &&
             config->gdb_regmap.reg[i].type != xtRegisterTypeMapped &&
             config->gdb_regmap.reg[i].type != xtRegisterTypeUnmapped) {
             ++*n_regs;
-            if ((config->gdb_regmap.reg[i].flags &
-                 XTENSA_REGISTER_FLAGS_PRIVILEGED) == 0) {
-                ++*n_core_regs;
+            if (count_core_regs) {
+                if ((config->gdb_regmap.reg[i].flags &
+                     XTENSA_REGISTER_FLAGS_PRIVILEGED) == 0) {
+                    ++*n_core_regs;
+                } else {
+                    count_core_regs = false;
+                }
             }
         }
     }