gdbstub: Infer number of core registers from XML

GDBFeature has the num_regs member so use it where applicable to
remove magic numbers.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20231213-gdb-v17-8-777047380591@daynix.com>
[AJB: remove core reg check from microblaze read reg]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240227144335.1196131-13-alex.bennee@linaro.org>

gdbstub/gdbstub.c

@@ -546,9 +546,12 @@ void gdb_init_cpu(CPUState *cpu)
         gdb_register_feature(cpu, 0,
                              cc->gdb_read_register, cc->gdb_write_register,
                              feature);
+        cpu->gdb_num_regs = cpu->gdb_num_g_regs = feature->num_regs;
     }
 
-    cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
+    if (cc->gdb_num_core_regs) {
+        cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
+    }
 }
 
 void gdb_register_coprocessor(CPUState *cpu,

include/hw/core/cpu.h

@@ -126,7 +126,8 @@ struct SysemuCPUOps;
  * @gdb_adjust_breakpoint: Callback for adjusting the address of a
  *       breakpoint.  Used by AVR to handle a gdb mis-feature with
  *       its Harvard architecture split code and data.
- * @gdb_num_core_regs: Number of core registers accessible to GDB.
+ * @gdb_num_core_regs: Number of core registers accessible to GDB or 0 to infer
+ *                     from @gdb_core_xml_file.
  * @gdb_core_xml_file: File name for core registers GDB XML description.
  * @gdb_stop_before_watchpoint: Indicates whether GDB expects the CPU to stop
  *           before the insn which triggers a watchpoint rather than after it.

target/arm/cpu.c

@@ -2515,7 +2515,6 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data)
 #ifndef CONFIG_USER_ONLY
     cc->sysemu_ops = &arm_sysemu_ops;
 #endif
-    cc->gdb_num_core_regs = 26;
     cc->gdb_arch_name = arm_gdb_arch_name;
     cc->gdb_get_dynamic_xml = arm_gdb_get_dynamic_xml;
     cc->gdb_stop_before_watchpoint = true;

target/arm/cpu64.c

@@ -793,7 +793,6 @@ static void aarch64_cpu_class_init(ObjectClass *oc, void *data)
 
     cc->gdb_read_register = aarch64_cpu_gdb_read_register;
     cc->gdb_write_register = aarch64_cpu_gdb_write_register;
-    cc->gdb_num_core_regs = 34;
     cc->gdb_core_xml_file = "aarch64-core.xml";
     cc->gdb_arch_name = aarch64_gdb_arch_name;
 

target/avr/cpu.c

@@ -251,7 +251,6 @@ static void avr_cpu_class_init(ObjectClass *oc, void *data)
     cc->gdb_read_register = avr_cpu_gdb_read_register;
     cc->gdb_write_register = avr_cpu_gdb_write_register;
     cc->gdb_adjust_breakpoint = avr_cpu_gdb_adjust_breakpoint;
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "avr-cpu.xml";
     cc->tcg_ops = &avr_tcg_ops;
 }

target/hexagon/cpu.c

@@ -362,7 +362,6 @@ static void hexagon_cpu_class_init(ObjectClass *c, void *data)
     cc->get_pc = hexagon_cpu_get_pc;
     cc->gdb_read_register = hexagon_gdb_read_register;
     cc->gdb_write_register = hexagon_gdb_write_register;
-    cc->gdb_num_core_regs = TOTAL_PER_THREAD_REGS;
     cc->gdb_stop_before_watchpoint = true;
     cc->gdb_core_xml_file = "hexagon-core.xml";
     cc->disas_set_info = hexagon_cpu_disas_set_info;

target/i386/cpu.c

@@ -7990,10 +7990,8 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
     cc->gdb_arch_name = x86_gdb_arch_name;
 #ifdef TARGET_X86_64
     cc->gdb_core_xml_file = "i386-64bit.xml";
-    cc->gdb_num_core_regs = 66;
 #else
     cc->gdb_core_xml_file = "i386-32bit.xml";
-    cc->gdb_num_core_regs = 50;
 #endif
     cc->disas_set_info = x86_disas_set_info;
 

target/loongarch/cpu.c

@@ -815,7 +815,6 @@ static void loongarch32_cpu_class_init(ObjectClass *c, void *data)
 {
     CPUClass *cc = CPU_CLASS(c);
 
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "loongarch-base32.xml";
     cc->gdb_arch_name = loongarch32_gdb_arch_name;
 }
@@ -829,7 +828,6 @@ static void loongarch64_cpu_class_init(ObjectClass *c, void *data)
 {
     CPUClass *cc = CPU_CLASS(c);
 
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "loongarch-base64.xml";
     cc->gdb_arch_name = loongarch64_gdb_arch_name;
 }

target/m68k/cpu.c

@@ -570,7 +570,6 @@ static void m68k_cpu_class_init(ObjectClass *c, void *data)
 #endif
     cc->disas_set_info = m68k_cpu_disas_set_info;
 
-    cc->gdb_num_core_regs = 18;
     cc->tcg_ops = &m68k_tcg_ops;
 }
 

target/microblaze/cpu.c

@@ -444,7 +444,6 @@ static void mb_cpu_class_init(ObjectClass *oc, void *data)
     cc->sysemu_ops = &mb_sysemu_ops;
 #endif
     device_class_set_props(dc, mb_properties);
-    cc->gdb_num_core_regs = 32 + 25;
     cc->gdb_core_xml_file = "microblaze-core.xml";
 
     cc->disas_set_info = mb_disas_set_info;

target/microblaze/gdbstub.c

@@ -49,14 +49,9 @@ enum {
 int mb_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
     MicroBlazeCPU *cpu = MICROBLAZE_CPU(cs);
-    CPUClass *cc = CPU_GET_CLASS(cs);
     CPUMBState *env = &cpu->env;
     uint32_t val;
 
-    if (n > cc->gdb_num_core_regs) {
-        return 0;
-    }
-
     switch (n) {
     case 1 ... 31:
         val = env->regs[n];

target/riscv/cpu.c

@@ -2352,7 +2352,6 @@ static void riscv_cpu_common_class_init(ObjectClass *c, void *data)
     cc->get_pc = riscv_cpu_get_pc;
     cc->gdb_read_register = riscv_cpu_gdb_read_register;
     cc->gdb_write_register = riscv_cpu_gdb_write_register;
-    cc->gdb_num_core_regs = 33;
     cc->gdb_stop_before_watchpoint = true;
     cc->disas_set_info = riscv_cpu_disas_set_info;
 #ifndef CONFIG_USER_ONLY

target/rx/cpu.c

@@ -221,7 +221,6 @@ static void rx_cpu_class_init(ObjectClass *klass, void *data)
     cc->gdb_write_register = rx_cpu_gdb_write_register;
     cc->disas_set_info = rx_cpu_disas_set_info;
 
-    cc->gdb_num_core_regs = 26;
     cc->gdb_core_xml_file = "rx-core.xml";
     cc->tcg_ops = &rx_tcg_ops;
 }

target/s390x/cpu.c

@@ -368,7 +368,6 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     s390_cpu_class_init_sysemu(cc);
 #endif
     cc->disas_set_info = s390_cpu_disas_set_info;
-    cc->gdb_num_core_regs = S390_NUM_CORE_REGS;
     cc->gdb_core_xml_file = "s390x-core64.xml";
     cc->gdb_arch_name = s390_gdb_arch_name;
 

target/s390x/cpu.h

@@ -491,8 +491,6 @@ static inline void cpu_get_tb_cpu_state(CPUS390XState *env, vaddr *pc,
 #define S390_R13_REGNUM 15
 #define S390_R14_REGNUM 16
 #define S390_R15_REGNUM 17
-/* Total Core Registers. */
-#define S390_NUM_CORE_REGS 18
 
 static inline void setcc(S390CPU *cpu, uint64_t cc)
 {