diff --git a/core/api/current.txt b/core/api/current.txt
index 935cf70..aaa4c2d 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -40190,6 +40190,7 @@
     field public static final int DURATION_MEDIUM = 2; // 0x2
     field public static final int DURATION_SHORT = 1; // 0x1
     field public static final int DURATION_VERY_SHORT = 0; // 0x0
+    field public static final long ENABLE_GET_CALL_STATE_PERMISSION_PROTECTION = 157233955L; // 0x95f3323L
     field public static final String EXTRA_CALL_BACK_NUMBER = "android.telecom.extra.CALL_BACK_NUMBER";
     field public static final String EXTRA_CALL_DISCONNECT_CAUSE = "android.telecom.extra.CALL_DISCONNECT_CAUSE";
     field public static final String EXTRA_CALL_DISCONNECT_MESSAGE = "android.telecom.extra.CALL_DISCONNECT_MESSAGE";
@@ -41796,7 +41797,7 @@
     method @Deprecated public void onBarringInfoChanged(@NonNull android.telephony.BarringInfo);
     method @Deprecated @RequiresPermission(android.Manifest.permission.READ_PRECISE_PHONE_STATE) public void onCallDisconnectCauseChanged(int, int);
     method @Deprecated public void onCallForwardingIndicatorChanged(boolean);
-    method @Deprecated public void onCallStateChanged(int, String);
+    method @Deprecated @RequiresPermission(value=android.Manifest.permission.READ_PHONE_STATE, conditional=true) public void onCallStateChanged(int, String);
     method @Deprecated public void onCellInfoChanged(java.util.List<android.telephony.CellInfo>);
     method @Deprecated public void onCellLocationChanged(android.telephony.CellLocation);
     method @Deprecated public void onDataActivity(int);
@@ -42342,7 +42343,7 @@
   }
 
   public static interface TelephonyCallback.CallStateListener {
-    method public void onCallStateChanged(int);
+    method @RequiresPermission(android.Manifest.permission.READ_PHONE_STATE) public void onCallStateChanged(int);
   }
 
   public static interface TelephonyCallback.CarrierNetworkListener {
@@ -42432,7 +42433,8 @@
     method public int getActiveModemCount();
     method @RequiresPermission(android.Manifest.permission.ACCESS_FINE_LOCATION) public java.util.List<android.telephony.CellInfo> getAllCellInfo();
     method @RequiresPermission("android.permission.READ_PRIVILEGED_PHONE_STATE") public int getCallComposerStatus();
-    method public int getCallState();
+    method @Deprecated @RequiresPermission(value=android.Manifest.permission.READ_PHONE_STATE, conditional=true) public int getCallState();
+    method @RequiresPermission(android.Manifest.permission.READ_PHONE_STATE) public int getCallStateForSubscription();
     method public int getCardIdForDefaultEuicc();
     method @RequiresPermission(android.Manifest.permission.READ_PHONE_STATE) @WorkerThread public android.os.PersistableBundle getCarrierConfig();
     method public int getCarrierIdFromSimMccMnc();
diff --git a/core/api/system-current.txt b/core/api/system-current.txt
index e8bdd41..8987802 100644
--- a/core/api/system-current.txt
+++ b/core/api/system-current.txt
@@ -10880,7 +10880,7 @@
     method public java.util.List<android.telecom.PhoneAccount> getAllPhoneAccounts();
     method public int getAllPhoneAccountsCount();
     method @NonNull @RequiresPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE) public java.util.List<android.telecom.PhoneAccountHandle> getCallCapablePhoneAccounts(boolean);
-    method public int getCallState();
+    method @RequiresPermission(anyOf={android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE, android.Manifest.permission.READ_PHONE_STATE}, conditional=true) public int getCallState();
     method public android.telecom.PhoneAccountHandle getConnectionManager();
     method @RequiresPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE) public int getCurrentTtyMode();
     method @Nullable @RequiresPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE) public String getDefaultDialerPackage(@NonNull android.os.UserHandle);
diff --git a/core/java/android/telephony/PhoneStateListener.java b/core/java/android/telephony/PhoneStateListener.java
index 1da7dc4..49065aa 100644
--- a/core/java/android/telephony/PhoneStateListener.java
+++ b/core/java/android/telephony/PhoneStateListener.java
@@ -703,6 +703,10 @@
      * calling {@link TelephonyManager#getCallState()} from within this callback may return a
      * different state than the callback reports.
      *
+     * Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} for applications
+     * targeting API level 31+.
+     *
      * @param state call state
      * @param phoneNumber call phone number. If application does not have
      * {@link android.Manifest.permission#READ_CALL_LOG READ_CALL_LOG} permission or carrier
@@ -712,6 +716,7 @@
      * @deprecated Use {@link TelephonyCallback.CallStateListener} instead.
      */
     @Deprecated
+    @RequiresPermission(value = android.Manifest.permission.READ_PHONE_STATE, conditional = true)
     public void onCallStateChanged(@CallState int state, String phoneNumber) {
         // default implementation empty
     }
diff --git a/core/java/android/telephony/TelephonyCallback.java b/core/java/android/telephony/TelephonyCallback.java
index 18949cd..1ab6e0f 100644
--- a/core/java/android/telephony/TelephonyCallback.java
+++ b/core/java/android/telephony/TelephonyCallback.java
@@ -752,6 +752,7 @@
          *
          * @param state the current call state
          */
+        @RequiresPermission(android.Manifest.permission.READ_PHONE_STATE)
         public void onCallStateChanged(@Annotation.CallState int state);
     }
 
diff --git a/services/core/java/com/android/server/TelephonyRegistry.java b/services/core/java/com/android/server/TelephonyRegistry.java
index 3ea4458..b42a16d 100644
--- a/services/core/java/com/android/server/TelephonyRegistry.java
+++ b/services/core/java/com/android/server/TelephonyRegistry.java
@@ -44,6 +44,7 @@
 import android.os.RemoteException;
 import android.os.UserHandle;
 import android.provider.DeviceConfig;
+import android.telecom.TelecomManager;
 import android.telephony.Annotation;
 import android.telephony.Annotation.RadioPowerState;
 import android.telephony.Annotation.SrvccState;
@@ -215,6 +216,18 @@
             return Binder.withCleanCallingIdentity(() -> CompatChanges.isChangeEnabled(
                     TelephonyCallback.PHONE_STATE_LISTENER_LIMIT_CHANGE_ID, uid));
         }
+
+        /**
+         * See {@link TelecomManager#ENABLE_GET_CALL_STATE_PERMISSION_PROTECTION} for more
+         * information.
+         * @noinspection ConstantConditions
+         */
+        public boolean isCallStateReadPhoneStateEnforcedInPlatformCompat(String packageName,
+                UserHandle userHandle) {
+            return Binder.withCleanCallingIdentity(() -> CompatChanges.isChangeEnabled(
+                    TelecomManager.ENABLE_GET_CALL_STATE_PERMISSION_PROTECTION, packageName,
+                    userHandle));
+        }
     }
 
     private final Context mContext;
@@ -2947,6 +2960,19 @@
             }
         }
 
+        // Only check READ_PHONE_STATE for CALL_STATE_CHANGED for API 31+.
+        if (mConfigurationProvider.isCallStateReadPhoneStateEnforcedInPlatformCompat(callingPackage,
+                Binder.getCallingUserHandle())) {
+            if (events.contains(TelephonyCallback.EVENT_LEGACY_CALL_STATE_CHANGED)
+                    || events.contains(TelephonyCallback.EVENT_CALL_STATE_CHANGED)) {
+                if (!TelephonyPermissions.checkCallingOrSelfReadPhoneState(
+                        mContext, subId, callingPackage, callingFeatureId, message)) {
+                    throw new SecurityException("CALL_STATE_CHANGED event requires "
+                            + "READ_PHONE_STATE");
+                }
+            }
+        }
+
         if (isPrecisePhoneStatePermissionRequired(events)) {
             // check if calling app has either permission READ_PRECISE_PHONE_STATE
             // or with carrier privileges
diff --git a/telecomm/java/android/telecom/TelecomManager.java b/telecomm/java/android/telecom/TelecomManager.java
index 1677c8c..4886789 100644
--- a/telecomm/java/android/telecom/TelecomManager.java
+++ b/telecomm/java/android/telecom/TelecomManager.java
@@ -25,6 +25,8 @@
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
 import android.annotation.SystemService;
+import android.compat.annotation.ChangeId;
+import android.compat.annotation.EnabledSince;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.ComponentName;
 import android.content.Context;
@@ -1004,6 +1006,17 @@
             PRESENTATION_PAYPHONE})
     public @interface Presentation {}
 
+
+    /**
+     * Enable READ_PHONE_STATE protection on APIs querying and notifying call state, such as
+     * {@code TelecomManager#getCallState}, {@link TelephonyManager#getCallStateForSubscription()},
+     * and {@link android.telephony.TelephonyCallback.CallStateListener}.
+     */
+    @ChangeId
+    @EnabledSince(targetSdkVersion = Build.VERSION_CODES.S)
+    // this magic number is a bug ID
+    public static final long ENABLE_GET_CALL_STATE_PERMISSION_PROTECTION = 157233955L;
+
     private static final String TAG = "TelecomManager";
 
 
@@ -1758,21 +1771,23 @@
      * {@link TelephonyManager#CALL_STATE_OFFHOOK}
      * {@link TelephonyManager#CALL_STATE_IDLE}
      *
-     * Note that this API does not require the
-     * {@link android.Manifest.permission#READ_PHONE_STATE} permission. This is intentional, to
-     * preserve the behavior of {@link TelephonyManager#getCallState()}, which also did not require
-     * the permission.
-     *
      * Takes into consideration both managed and self-managed calls.
+     * <p>
+     * Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} for applications
+     * targeting API level 31+.
      *
      * @hide
      */
+    @RequiresPermission(anyOf = {READ_PRIVILEGED_PHONE_STATE,
+            android.Manifest.permission.READ_PHONE_STATE}, conditional = true)
     @SystemApi
     public @CallState int getCallState() {
         ITelecomService service = getTelecomService();
         if (service != null) {
             try {
-                return service.getCallState();
+                return service.getCallStateUsingPackage(mContext.getPackageName(),
+                        mContext.getAttributionTag());
             } catch (RemoteException e) {
                 Log.d(TAG, "RemoteException calling getCallState().", e);
             }
diff --git a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
index 78283fa..18afde7 100644
--- a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
+++ b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
@@ -195,11 +195,18 @@
 
     /**
      * @see TelecomServiceImpl#getCallState
+     * Note: only kept around to not break app compat, however this will throw a SecurityException
+     * on API 31+.
      */
     @UnsupportedAppUsage(maxTargetSdk = 30, trackingBug = 170729553)
     int getCallState();
 
     /**
+     * @see TelecomServiceImpl#getCallState
+     */
+    int getCallStateUsingPackage(String callingPackage, String callingFeatureId);
+
+    /**
      * @see TelecomServiceImpl#endCall
      */
     boolean endCall(String callingPackage);
diff --git a/telephony/java/android/telephony/TelephonyManager.java b/telephony/java/android/telephony/TelephonyManager.java
index d2da51a..eed42d9 100644
--- a/telephony/java/android/telephony/TelephonyManager.java
+++ b/telephony/java/android/telephony/TelephonyManager.java
@@ -5702,9 +5702,20 @@
      * Note: The call state returned via this method may differ from what is reported by
      * {@link PhoneStateListener#onCallStateChanged(int, String)}, as that callback only considers
      * Telephony (mobile) calls.
+     * <p>
+     * Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} for applications
+     * targeting API level 31+.
      *
      * @return the current call state.
+     * @deprecated Use {@link #getCallStateForSubscription} to retrieve the call state for a
+     * specific telephony subscription (which allows carrier privileged apps),
+     * {@link TelephonyCallback.CallStateListener} for real-time call state updates, or
+     * {@link TelecomManager#isInCall()}, which supplies an aggregate "in call" state for the entire
+     * device.
      */
+    @RequiresPermission(value = android.Manifest.permission.READ_PHONE_STATE, conditional = true)
+    @Deprecated
     public @CallState int getCallState() {
         if (mContext != null) {
             TelecomManager telecomManager = mContext.getSystemService(TelecomManager.class);
@@ -5716,19 +5727,48 @@
     }
 
     /**
+     * Retrieve the call state for a specific subscription that was specified when this
+     * TelephonyManager instance was created.
+     * <p>Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} or that the calling
+     * application has carrier privileges (see {@link #hasCarrierPrivileges}).
+     * @see TelephonyManager#createForSubscriptionId(int)
+     * @see TelephonyManager#createForPhoneAccountHandle(PhoneAccountHandle)
+     * @return The call state of the subscription associated with this TelephonyManager instance.
+     */
+    @RequiresPermission(android.Manifest.permission.READ_PHONE_STATE)
+    public @CallState int getCallStateForSubscription() {
+        return getCallState(getSubId());
+    }
+
+    /**
      * Returns the Telephony call state for calls on a specific subscription.
      * <p>
      * Note: This method considers ONLY telephony/mobile calls, where {@link #getCallState()}
      * considers the state of calls from other {@link android.telecom.ConnectionService}
      * implementations.
+     * <p>
+     * Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} for applications
+     * targeting API level 31+ or that the calling application has carrier privileges
+     * (see {@link #hasCarrierPrivileges()}).
      *
      * @param subId the subscription to check call state for.
      * @hide
      */
     @UnsupportedAppUsage
+    @RequiresPermission(value = android.Manifest.permission.READ_PHONE_STATE, conditional = true)
     public @CallState int getCallState(int subId) {
-        int phoneId = SubscriptionManager.getPhoneId(subId);
-        return getCallStateForSlot(phoneId);
+        ITelephony telephony = getITelephony();
+        if (telephony == null) {
+            return CALL_STATE_IDLE;
+        }
+        try {
+            return telephony.getCallStateForSubscription(subId, mContext.getPackageName(),
+                    mContext.getAttributionTag());
+        } catch (RemoteException e) {
+            return CALL_STATE_IDLE;
+        }
     }
 
     /**
@@ -5745,22 +5785,28 @@
      * Note: This method considers ONLY telephony/mobile calls, where {@link #getCallState()}
      * considers the state of calls from other {@link android.telecom.ConnectionService}
      * implementations.
+     * <p>
+     * Requires Permission:
+     * {@link android.Manifest.permission#READ_PHONE_STATE READ_PHONE_STATE} for applications
+     * targeting API level 31+ or that the calling application has carrier privileges
+     * (see {@link #hasCarrierPrivileges()}).
      *
      * @param slotIndex the SIM slot index to check call state for.
      * @hide
      */
+    @RequiresPermission(value = android.Manifest.permission.READ_PHONE_STATE, conditional = true)
     public @CallState int getCallStateForSlot(int slotIndex) {
         try {
+            int[] subId = SubscriptionManager.getSubId(slotIndex);
             ITelephony telephony = getITelephony();
-            if (telephony == null)
+            if (telephony == null || subId == null || subId.length  == 0) {
                 return CALL_STATE_IDLE;
-            return telephony.getCallStateForSlot(slotIndex);
-        } catch (RemoteException ex) {
+            }
+            return telephony.getCallStateForSubscription(subId[0], mContext.getPackageName(),
+                    mContext.getAttributionTag());
+        } catch (RemoteException | NullPointerException ex) {
             // the phone process is restarting.
             return CALL_STATE_IDLE;
-        } catch (NullPointerException ex) {
-          // the phone process is restarting.
-          return CALL_STATE_IDLE;
         }
     }
 
diff --git a/telephony/java/com/android/internal/telephony/ITelephony.aidl b/telephony/java/com/android/internal/telephony/ITelephony.aidl
index 46752b7..afc538d 100644
--- a/telephony/java/com/android/internal/telephony/ITelephony.aidl
+++ b/telephony/java/com/android/internal/telephony/ITelephony.aidl
@@ -298,9 +298,9 @@
     int getCallState();
 
     /**
-     * Returns the call state for a slot.
+     * Returns the call state for a specific subscriiption.
      */
-    int getCallStateForSlot(int slotIndex);
+    int getCallStateForSubscription(int subId, String callingPackage, String featureId);
 
     /**
      * Replaced by getDataActivityForSubId.