target/arm: Adjust format test in scr_write

Because reset always initializes the AA64 version, SCR_EL3,
test the mode of EL3 instead of the type of the cpreg.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220609214657.1217913-2-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/helper.c

@@ -1738,12 +1738,14 @@ static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
     uint32_t valid_mask = 0x3fff;
     ARMCPU *cpu = env_archcpu(env);
 
-    if (ri->state == ARM_CP_STATE_AA64) {
-        if (arm_feature(env, ARM_FEATURE_AARCH64) &&
-            !cpu_isar_feature(aa64_aa32_el1, cpu)) {
-                value |= SCR_FW | SCR_AW;   /* these two bits are RES1.  */
-        }
-        valid_mask &= ~SCR_NET;
+    /*
+     * Because SCR_EL3 is the "real" cpreg and SCR is the alias, reset always
+     * passes the reginfo for SCR_EL3, which has type ARM_CP_STATE_AA64.
+     * Instead, choose the format based on the mode of EL3.
+     */
+    if (arm_el_is_aa64(env, 3)) {
+        value |= SCR_FW | SCR_AW;      /* RES1 */
+        valid_mask &= ~SCR_NET;        /* RES0 */
 
         if (cpu_isar_feature(aa64_ras, cpu)) {
             valid_mask |= SCR_TERR;