s390x/gdb: generate target.xml and handle fp/ac as coprocessors

This patch reduces the core registers to the psw and the general purpose
registers. The fpc and ac registers are handled as coprocessors registers by gdb.
This allows to reuse the feature xml files taken from gdb without further
modification and is what other architectures do.

The target.xml is now generated and provided to the gdb client. Therefore, the
client doesn't have to guess which registers are available at which logical
register number.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

target-s390x/cpu-qom.h

@@ -89,5 +89,6 @@ hwaddr s390_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 hwaddr s390_cpu_get_phys_addr_debug(CPUState *cpu, vaddr addr);
 int s390_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg);
 int s390_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
+void s390_cpu_gdb_init(CPUState *cs);
 
 #endif

target-s390x/cpu.c

@@ -174,6 +174,7 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
     CPUState *cs = CPU(dev);
     S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
 
+    s390_cpu_gdb_init(cs);
     qemu_init_vcpu(cs);
 #if !defined(CONFIG_USER_ONLY)
     run_on_cpu(cs, s390_do_cpu_full_reset, cs);
@@ -263,7 +264,8 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     cc->write_elf64_qemunote = s390_cpu_write_elf64_qemunote;
 #endif
     dc->vmsd = &vmstate_s390_cpu;
-    cc->gdb_num_core_regs = S390_NUM_REGS;
+    cc->gdb_num_core_regs = S390_NUM_CORE_REGS;
+    cc->gdb_core_xml_file = "s390x-core64.xml";
 }
 
 static const TypeInfo s390_cpu_type_info = {

target-s390x/cpu.h

@@ -566,44 +566,8 @@ void s390_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 #define S390_R13_REGNUM 15
 #define S390_R14_REGNUM 16
 #define S390_R15_REGNUM 17
-/* Access Registers.  */
-#define S390_A0_REGNUM 18
-#define S390_A1_REGNUM 19
-#define S390_A2_REGNUM 20
-#define S390_A3_REGNUM 21
-#define S390_A4_REGNUM 22
-#define S390_A5_REGNUM 23
-#define S390_A6_REGNUM 24
-#define S390_A7_REGNUM 25
-#define S390_A8_REGNUM 26
-#define S390_A9_REGNUM 27
-#define S390_A10_REGNUM 28
-#define S390_A11_REGNUM 29
-#define S390_A12_REGNUM 30
-#define S390_A13_REGNUM 31
-#define S390_A14_REGNUM 32
-#define S390_A15_REGNUM 33
-/* Floating Point Control Word.  */
-#define S390_FPC_REGNUM 34
-/* Floating Point Registers.  */
-#define S390_F0_REGNUM 35
-#define S390_F1_REGNUM 36
-#define S390_F2_REGNUM 37
-#define S390_F3_REGNUM 38
-#define S390_F4_REGNUM 39
-#define S390_F5_REGNUM 40
-#define S390_F6_REGNUM 41
-#define S390_F7_REGNUM 42
-#define S390_F8_REGNUM 43
-#define S390_F9_REGNUM 44
-#define S390_F10_REGNUM 45
-#define S390_F11_REGNUM 46
-#define S390_F12_REGNUM 47
-#define S390_F13_REGNUM 48
-#define S390_F14_REGNUM 49
-#define S390_F15_REGNUM 50
-/* Total.  */
-#define S390_NUM_REGS 51
+/* Total Core Registers. */
+#define S390_NUM_CORE_REGS 18
 
 /* CC optimization */
 

target-s390x/gdbstub.c

@@ -42,14 +42,7 @@ int s390_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
         return gdb_get_regl(mem_buf, env->psw.addr);
     case S390_R0_REGNUM ... S390_R15_REGNUM:
         return gdb_get_regl(mem_buf, env->regs[n-S390_R0_REGNUM]);
-    case S390_A0_REGNUM ... S390_A15_REGNUM:
-        return gdb_get_reg32(mem_buf, env->aregs[n-S390_A0_REGNUM]);
-    case S390_FPC_REGNUM:
-        return gdb_get_reg32(mem_buf, env->fpc);
-    case S390_F0_REGNUM ... S390_F15_REGNUM:
-        return gdb_get_reg64(mem_buf, env->fregs[n-S390_F0_REGNUM].ll);
     }
-
     return 0;
 }
 
@@ -57,11 +50,7 @@ int s390_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
 {
     S390CPU *cpu = S390_CPU(cs);
     CPUS390XState *env = &cpu->env;
-    target_ulong tmpl;
-    uint32_t tmp32;
-    int r = 8;
-    tmpl = ldtul_p(mem_buf);
-    tmp32 = ldl_p(mem_buf);
+    target_ulong tmpl = ldtul_p(mem_buf);
 
     switch (n) {
     case S390_PSWM_REGNUM:
@@ -76,19 +65,79 @@ int s390_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
     case S390_R0_REGNUM ... S390_R15_REGNUM:
         env->regs[n-S390_R0_REGNUM] = tmpl;
         break;
+    default:
+        return 0;
+    }
+    return 8;
+}
+
+/* the values represent the positions in s390-acr.xml */
+#define S390_A0_REGNUM 0
+#define S390_A15_REGNUM 15
+/* total number of registers in s390-acr.xml */
+#define S390_NUM_AC_REGS 16
+
+static int cpu_read_ac_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
     case S390_A0_REGNUM ... S390_A15_REGNUM:
-        env->aregs[n-S390_A0_REGNUM] = tmp32;
-        r = 4;
-        break;
+        return gdb_get_reg32(mem_buf, env->aregs[n]);
+    default:
+        return 0;
+    }
+}
+
+static int cpu_write_ac_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_A0_REGNUM ... S390_A15_REGNUM:
+        env->aregs[n] = ldl_p(mem_buf);
+        return 4;
+    default:
+        return 0;
+    }
+}
+
+/* the values represent the positions in s390-fpr.xml */
+#define S390_FPC_REGNUM 0
+#define S390_F0_REGNUM 1
+#define S390_F15_REGNUM 16
+/* total number of registers in s390-fpr.xml */
+#define S390_NUM_FP_REGS 17
+
+static int cpu_read_fp_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
     case S390_FPC_REGNUM:
-        env->fpc = tmp32;
-        r = 4;
-        break;
+        return gdb_get_reg32(mem_buf, env->fpc);
     case S390_F0_REGNUM ... S390_F15_REGNUM:
-        env->fregs[n-S390_F0_REGNUM].ll = tmpl;
-        break;
+        return gdb_get_reg64(mem_buf, env->fregs[n - S390_F0_REGNUM].ll);
     default:
         return 0;
     }
-    return r;
+}
+
+static int cpu_write_fp_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_FPC_REGNUM:
+        env->fpc = ldl_p(mem_buf);
+        return 4;
+    case S390_F0_REGNUM ... S390_F15_REGNUM:
+        env->fregs[n - S390_F0_REGNUM].ll = ldtul_p(mem_buf);
+        return 8;
+    default:
+        return 0;
+    }
+}
+
+void s390_cpu_gdb_init(CPUState *cs)
+{
+    gdb_register_coprocessor(cs, cpu_read_ac_reg,
+                             cpu_write_ac_reg,
+                             S390_NUM_AC_REGS, "s390-acr.xml", 0);
+
+    gdb_register_coprocessor(cs, cpu_read_fp_reg,
+                             cpu_write_fp_reg,
+                             S390_NUM_FP_REGS, "s390-fpr.xml", 0);
 }