target/arm: Implement UAO semantics

We need only override the current condition under which
TBFLAG_A64.UNPRIV is set.
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20200208125816.14954-20-richard.henderson@linaro.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target/arm/helper.c

@@ -12198,28 +12198,29 @@ static uint32_t rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
     }
 
     /* Compute the condition for using AccType_UNPRIV for LDTR et al. */
-    /* TODO: ARMv8.2-UAO */
-    switch (mmu_idx) {
-    case ARMMMUIdx_E10_1:
-    case ARMMMUIdx_E10_1_PAN:
-    case ARMMMUIdx_SE10_1:
-    case ARMMMUIdx_SE10_1_PAN:
-        /* TODO: ARMv8.3-NV */
-        flags = FIELD_DP32(flags, TBFLAG_A64, UNPRIV, 1);
-        break;
-    case ARMMMUIdx_E20_2:
-    case ARMMMUIdx_E20_2_PAN:
-        /* TODO: ARMv8.4-SecEL2 */
-        /*
-         * Note that E20_2 is gated by HCR_EL2.E2H == 1, but E20_0 is
-         * gated by HCR_EL2.<E2H,TGE> == '11', and so is LDTR.
-         */
-        if (env->cp15.hcr_el2 & HCR_TGE) {
+    if (!(env->pstate & PSTATE_UAO)) {
+        switch (mmu_idx) {
+        case ARMMMUIdx_E10_1:
+        case ARMMMUIdx_E10_1_PAN:
+        case ARMMMUIdx_SE10_1:
+        case ARMMMUIdx_SE10_1_PAN:
+            /* TODO: ARMv8.3-NV */
             flags = FIELD_DP32(flags, TBFLAG_A64, UNPRIV, 1);
+            break;
+        case ARMMMUIdx_E20_2:
+        case ARMMMUIdx_E20_2_PAN:
+            /* TODO: ARMv8.4-SecEL2 */
+            /*
+             * Note that EL20_2 is gated by HCR_EL2.E2H == 1, but EL20_0 is
+             * gated by HCR_EL2.<E2H,TGE> == '11', and so is LDTR.
+             */
+            if (env->cp15.hcr_el2 & HCR_TGE) {
+                flags = FIELD_DP32(flags, TBFLAG_A64, UNPRIV, 1);
+            }
+            break;
+        default:
+            break;
         }
-        break;
-    default:
-        break;
     }
 
     return rebuild_hflags_common(env, fp_el, mmu_idx, flags);