target/arm: Improve masking of SCR RES0 bits

Protect reads of aa64 id registers with ARM_CP_STATE_AA64.
Use this as a simpler test than arm_el_is_aa64, since EL3
cannot change mode.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200626033144.790098-3-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 972a766..a29f0a2 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -2011,9 +2011,16 @@ static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
     uint32_t valid_mask = 0x3fff;
     ARMCPU *cpu = env_archcpu(env);
 
-    if (arm_el_is_aa64(env, 3)) {
+    if (ri->state == ARM_CP_STATE_AA64) {
         value |= SCR_FW | SCR_AW;   /* these two bits are RES1.  */
         valid_mask &= ~SCR_NET;
+
+        if (cpu_isar_feature(aa64_lor, cpu)) {
+            valid_mask |= SCR_TLOR;
+        }
+        if (cpu_isar_feature(aa64_pauth, cpu)) {
+            valid_mask |= SCR_API | SCR_APK;
+        }
     } else {
         valid_mask &= ~(SCR_RW | SCR_ST);
     }
@@ -2032,12 +2039,6 @@ static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
             valid_mask &= ~SCR_SMD;
         }
     }
-    if (cpu_isar_feature(aa64_lor, cpu)) {
-        valid_mask |= SCR_TLOR;
-    }
-    if (cpu_isar_feature(aa64_pauth, cpu)) {
-        valid_mask |= SCR_API | SCR_APK;
-    }
 
     /* Clear all-context RES0 bits.  */
     value &= valid_mask;