target/alpha: Access CPUState::cpu_index via helper

CPUState::cpu_index is a target agnostic field, meant
for common code (i.e. accel/ and system/ folders).

Target specific code should use the CPUClass::get_arch_id()
helper, even if there is a 1:1 mapping.

In preparation of generic changes around CPU indexing,
introduce the whoami helper to access the generic
CPUState::cpu_index field.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250925010438.59755-1-philmd@linaro.org>

target/alpha/helper.h

@@ -92,6 +92,7 @@ DEF_HELPER_FLAGS_1(tbia, TCG_CALL_NO_RWG, void, env)
 DEF_HELPER_FLAGS_2(tbis, TCG_CALL_NO_RWG, void, env, i64)
 
 DEF_HELPER_1(halt, void, i64)
+DEF_HELPER_1(whami, i64, env)
 
 DEF_HELPER_FLAGS_0(get_vmtime, TCG_CALL_NO_RWG, i64)
 DEF_HELPER_FLAGS_0(get_walltime, TCG_CALL_NO_RWG, i64)

target/alpha/sys_helper.c

@@ -67,3 +67,8 @@ void helper_set_alarm(CPUAlphaState *env, uint64_t expire)
         timer_del(cpu->alarm_timer);
     }
 }
+
+uint64_t HELPER(whami)(CPUAlphaState *env)
+{
+    return env_cpu(env)->cpu_index;
+}

target/alpha/translate.c

@@ -1126,8 +1126,7 @@ static DisasJumpType gen_call_pal(DisasContext *ctx, int palcode)
             break;
         case 0x3C:
             /* WHAMI */
-            tcg_gen_ld32s_i64(ctx->ir[IR_V0], tcg_env,
-                -offsetof(AlphaCPU, env) + offsetof(CPUState, cpu_index));
+            gen_helper_whami(ctx->ir[IR_V0], tcg_env);
             break;
 
         case 0x3E: