s390x: gdb updates for vector registers

gdb allows registers to be displayed/modified, and is being updated
to account for the new vector registers.  Mirror these changes in
the gdb stub in qemu so that this can be performed when gdb is
attached to the qemu gdbserver.
Signed-off-by: NEric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

configure

@@ -5292,7 +5292,7 @@ case "$target_name" in
     echo "TARGET_ABI32=y" >> $config_target_mak
   ;;
   s390x)
-    gdb_xml_files="s390x-core64.xml s390-acr.xml s390-fpr.xml"
+    gdb_xml_files="s390x-core64.xml s390-acr.xml s390-fpr.xml s390-vx.xml"
   ;;
   tricore)
   ;;

target-s390x/gdbstub.c

@@ -131,6 +131,48 @@ static int cpu_write_fp_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
     }
 }
 
+/* the values represent the positions in s390-vx.xml */
+#define S390_V0L_REGNUM 0
+#define S390_V15L_REGNUM 15
+#define S390_V16_REGNUM 16
+#define S390_V31_REGNUM 31
+/* total number of registers in s390-vx.xml */
+#define S390_NUM_VREGS 32
+
+static int cpu_read_vreg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    int ret;
+
+    switch (n) {
+    case S390_V0L_REGNUM ... S390_V15L_REGNUM:
+        ret = gdb_get_reg64(mem_buf, env->vregs[n][1].ll);
+        break;
+    case S390_V16_REGNUM ... S390_V31_REGNUM:
+        ret = gdb_get_reg64(mem_buf, env->vregs[n][0].ll);
+        ret += gdb_get_reg64(mem_buf + 8, env->vregs[n][1].ll);
+        break;
+    default:
+        ret = 0;
+    }
+
+    return ret;
+}
+
+static int cpu_write_vreg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_V0L_REGNUM ... S390_V15L_REGNUM:
+        env->vregs[n][1].ll = ldtul_p(mem_buf + 8);
+        return 8;
+    case S390_V16_REGNUM ... S390_V31_REGNUM:
+        env->vregs[n][0].ll = ldtul_p(mem_buf);
+        env->vregs[n][1].ll = ldtul_p(mem_buf + 8);
+        return 16;
+    default:
+        return 0;
+    }
+}
+
 void s390_cpu_gdb_init(CPUState *cs)
 {
     gdb_register_coprocessor(cs, cpu_read_ac_reg,
@@ -140,4 +182,8 @@ void s390_cpu_gdb_init(CPUState *cs)
     gdb_register_coprocessor(cs, cpu_read_fp_reg,
                              cpu_write_fp_reg,
                              S390_NUM_FP_REGS, "s390-fpr.xml", 0);
+
+    gdb_register_coprocessor(cs, cpu_read_vreg,
+                             cpu_write_vreg,
+                             S390_NUM_VREGS, "s390-vx.xml", 0);
 }