gdbstub: Do not use memset() on GByteArray

Introduce gdb_get_zeroes() to fill a GByteArray with zeroes.

Fixes: a010bdb ("extend GByteArray to read register helpers")
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>
[AJB: used slightly more gliby set_size approach]
Signed-off-by: Alex Bennée <[email protected]>
Message-Id: <[email protected]>

Author: philmd

include/exec/gdbstub.h

@@ -125,6 +125,15 @@ static inline int gdb_get_reg128(GByteArray *buf, uint64_t val_hi,
     return 16;
 }
 
+static inline int gdb_get_zeroes(GByteArray *array, size_t len)
+{
+    guint oldlen = array->len;
+    g_byte_array_set_size(array, oldlen + len);
+    memset(array->data + oldlen, 0, len);
+
+    return len;
+}
+
 /**
  * gdb_get_reg_ptr: get pointer to start of last element
  * @len: length of element

target/arm/gdbstub.c

@@ -47,8 +47,7 @@ int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
         if (gdb_has_xml) {
             return 0;
         }
-        memset(mem_buf, 0, 12);
-        return 12;
+        return gdb_get_zeroes(mem_buf, 12);
     }
     switch (n) {
     case 24:

target/xtensa/gdbstub.c

@@ -105,8 +105,7 @@ int xtensa_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
         default:
             qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported size %d\n",
                           __func__, n, reg->size);
-            memset(mem_buf, 0, reg->size);
-            return reg->size;
+            return gdb_get_zeroes(mem_buf, reg->size);
         }
 
     case xtRegisterTypeWindow: /*a*/
@@ -115,8 +114,7 @@ int xtensa_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
     default:
         qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported type %d\n",
                       __func__, n, reg->type);
-        memset(mem_buf, 0, reg->size);
-        return reg->size;
+        return gdb_get_zeroes(mem_buf, reg->size);
     }
 }