Refactor NativeHeapTagging compat feature.

Move the logic to startProcessLocked so that it can use app info/flags.

Bug: 135754954
Test: NFC
Change-Id: I50cfb8d0ec4ce1f79dec56b8bef09752a1b37490
Merged-In: Ief86185c6866640700e2548259df9ba1fb617e4d
(cherry picked from commit 5750d3b1532b399b2c654f534aaffd5473d0b3a4)

6 files changed, 52 insertions, 39 deletions

diff --git a/core/java/com/android/internal/os/RuntimeInit.java b/core/java/com/android/internal/os/RuntimeInit.java
index 16c0b5600f17..13d0c5c831b6 100644
--- a/core/java/com/android/internal/os/RuntimeInit.java
+++ b/core/java/com/android/internal/os/RuntimeInit.java
@@ -19,8 +19,6 @@ package com.android.internal.os;
 import android.app.ActivityManager;
 import android.app.ActivityThread;
 import android.app.ApplicationErrorReport;
-import android.compat.annotation.ChangeId;
-import android.compat.annotation.EnabledAfter;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.type.DefaultMimeMapFactory;
 import android.os.Build;
@@ -36,7 +34,6 @@ import android.util.Slog;
 import com.android.internal.logging.AndroidConfig;
 import com.android.server.NetworkManagementSocketTagger;
 
-import dalvik.annotation.compat.VersionCodes;
 import dalvik.system.RuntimeHooks;
 import dalvik.system.ThreadPrioritySetter;
 import dalvik.system.VMRuntime;
@@ -67,18 +64,8 @@ public class RuntimeInit {
 
     private static volatile boolean mCrashing = false;
 
-    /**
-     * Native heap allocations will now have a non-zero tag in the most significant byte.
-     * See
-     * <a href="https://source.android.com/devices/tech/debug/tagged-pointers">https://source.android.com/devices/tech/debug/tagged-pointers</a>.
-     */
-    @ChangeId
-    @EnabledAfter(targetSdkVersion = VersionCodes.Q)
-    private static final long NATIVE_HEAP_POINTER_TAGGING = 135754954; // This is a bug id.
-
     private static final native void nativeFinishInit();
     private static final native void nativeSetExitWithoutCleanup(boolean exitWithoutCleanup);
-    private static native void nativeDisableHeapPointerTagging();
 
     private static int Clog_e(String tag, String msg, Throwable tr) {
         return Log.printlns(Log.LOG_ID_CRASH, Log.ERROR, tag, msg, tr);
@@ -411,20 +398,6 @@ public class RuntimeInit {
         if (DEBUG) Slog.d(TAG, "Leaving RuntimeInit!");
     }
 
-    private static void maybeDisableHeapPointerTagging(long[] disabledCompatChanges) {
-        // Heap tagging needs to be disabled before any additional threads are created, but the
-        // AppCompat framework is not initialized enough at this point.
-        // Check if the change is enabled manually.
-        if (disabledCompatChanges != null) {
-            for (int i = 0; i < disabledCompatChanges.length; i++) {
-                if (disabledCompatChanges[i] == NATIVE_HEAP_POINTER_TAGGING) {
-                    nativeDisableHeapPointerTagging();
-                    break;
-                }
-            }
-        }
-    }
-
     protected static Runnable applicationInit(int targetSdkVersion, long[] disabledCompatChanges,
             String[] argv, ClassLoader classLoader) {
         // If the application calls System.exit(), terminate the process
@@ -437,8 +410,6 @@ public class RuntimeInit {
         VMRuntime.getRuntime().setTargetSdkVersion(targetSdkVersion);
         VMRuntime.getRuntime().setDisabledCompatChanges(disabledCompatChanges);
 
-        maybeDisableHeapPointerTagging(disabledCompatChanges);
-
         final Arguments args = new Arguments(argv);
 
         // The end of of the RuntimeInit event (see #zygoteInit).
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index bcb6c0f9ae87..d7b93b1c516c 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -122,6 +122,25 @@ public final class Zygote {
      */
     public static final int DISABLE_TEST_API_ENFORCEMENT_POLICY = 1 << 18;
 
+    public static final int MEMORY_TAG_LEVEL_MASK = (1 << 19) | (1 << 20);
+    /**
+     * Enable pointer tagging in this process.
+     * Tags are checked during memory deallocation, but not on access.
+     * TBI stands for Top-Byte-Ignore, an ARM CPU feature.
+     * {@link https://developer.arm.com/docs/den0024/latest/the-memory-management-unit/translation-table-configuration/virtual-address-tagging}
+     */
+    public static final int MEMORY_TAG_LEVEL_TBI = 1 << 19;
+
+    /**
+     * Enable asynchronous memory tag checks in this process.
+     */
+    public static final int MEMORY_TAG_LEVEL_ASYNC = 2 << 19;
+
+    /**
+     * Enable synchronous memory tag checks in this process.
+     */
+    public static final int MEMORY_TAG_LEVEL_SYNC = 3 << 19;
+
     /** No external storage should be mounted. */
     public static final int MOUNT_EXTERNAL_NONE = IVold.REMOUNT_MODE_NONE;
     /** Default external storage should be mounted. */
diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java
index 1b81a06f8b9a..ad835058afd0 100644
--- a/core/java/com/android/internal/os/ZygoteInit.java
+++ b/core/java/com/android/internal/os/ZygoteInit.java
@@ -782,6 +782,10 @@ public class ZygoteInit {
             Zygote.applyDebuggerSystemProperty(parsedArgs);
             Zygote.applyInvokeWithSystemProperty(parsedArgs);
 
+            /* Enable pointer tagging in the system server unconditionally. Hardware support for
+             * this is present in all ARMv8 CPUs; this flag has no effect on other platforms. */
+            parsedArgs.mRuntimeFlags |= Zygote.MEMORY_TAG_LEVEL_TBI;
+
             if (shouldProfileSystemServer()) {
                 parsedArgs.mRuntimeFlags |= Zygote.PROFILE_SYSTEM_SERVER;
             }
diff --git a/core/jni/AndroidRuntime.cpp b/core/jni/AndroidRuntime.cpp
index 5b80af51bb90..5c3640e3b9a0 100644
--- a/core/jni/AndroidRuntime.cpp
+++ b/core/jni/AndroidRuntime.cpp
@@ -282,14 +282,6 @@ static void com_android_internal_os_RuntimeInit_nativeSetExitWithoutCleanup(JNIE
     gCurRuntime->setExitWithoutCleanup(exitWithoutCleanup);
 }
 
-static void com_android_internal_os_RuntimeInit_nativeDisableHeapPointerTagging(
-        JNIEnv* env, jobject clazz) {
-    HeapTaggingLevel tag_level = M_HEAP_TAGGING_LEVEL_NONE;
-    if (!android_mallopt(M_SET_HEAP_TAGGING_LEVEL, &tag_level, sizeof(tag_level))) {
-        ALOGE("ERROR: could not disable heap pointer tagging\n");
-    }
-}
-
 /*
  * JNI registration.
  */
@@ -301,8 +293,6 @@ int register_com_android_internal_os_RuntimeInit(JNIEnv* env)
              (void*)com_android_internal_os_RuntimeInit_nativeFinishInit},
             {"nativeSetExitWithoutCleanup", "(Z)V",
              (void*)com_android_internal_os_RuntimeInit_nativeSetExitWithoutCleanup},
-            {"nativeDisableHeapPointerTagging", "()V",
-             (void*)com_android_internal_os_RuntimeInit_nativeDisableHeapPointerTagging},
     };
     return jniRegisterNativeMethods(env, "com/android/internal/os/RuntimeInit",
         methods, NELEM(methods));
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 7a93d8db0931..941a90fd1021 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -319,6 +319,8 @@ enum MountExternalKind {
 enum RuntimeFlags : uint32_t {
   DEBUG_ENABLE_JDWP = 1,
   PROFILE_FROM_SHELL = 1 << 15,
+  MEMORY_TAG_LEVEL_MASK = (1 << 19) | (1 << 20),
+  MEMORY_TAG_LEVEL_TBI = 1 << 19,
 };
 
 enum UnsolicitedZygoteMessageTypes : uint32_t {
@@ -1157,6 +1159,16 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
     }
   }
 
+  HeapTaggingLevel heap_tagging_level;
+  switch (runtime_flags & RuntimeFlags::MEMORY_TAG_LEVEL_MASK) {
+    case RuntimeFlags::MEMORY_TAG_LEVEL_TBI:
+      heap_tagging_level = M_HEAP_TAGGING_LEVEL_TBI;
+      break;
+    default:
+      heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE;
+  }
+  android_mallopt(M_SET_HEAP_TAGGING_LEVEL, &heap_tagging_level, sizeof(heap_tagging_level));
+
   if (NeedsNoRandomizeWorkaround()) {
     // Work around ARM kernel ASLR lossage (http://b/5817320).
     int old_personality = personality(0xffffffff);
diff --git a/services/core/java/com/android/server/am/ProcessList.java b/services/core/java/com/android/server/am/ProcessList.java
index c2652c06e5a9..8520cb7c30b8 100644
--- a/services/core/java/com/android/server/am/ProcessList.java
+++ b/services/core/java/com/android/server/am/ProcessList.java
@@ -51,6 +51,9 @@ import android.app.ActivityThread;
 import android.app.AppGlobals;
 import android.app.AppProtoEnums;
 import android.app.IApplicationThread;
+import android.app.IUidObserver;
+import android.compat.annotation.ChangeId;
+import android.compat.annotation.EnabledAfter;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
@@ -103,6 +106,7 @@ import com.android.server.pm.dex.DexManager;
 import com.android.server.wm.ActivityServiceConnectionsHolder;
 import com.android.server.wm.WindowManagerService;
 
+import dalvik.annotation.compat.VersionCodes;
 import dalvik.system.VMRuntime;
 
 import java.io.File;
@@ -280,6 +284,15 @@ public final class ProcessList {
     // lmkd reconnect delay in msecs
     private static final long LMKD_RECONNECT_DELAY_MS = 1000;
 
+    /**
+     * Native heap allocations will now have a non-zero tag in the most significant byte.
+     * @see <a href="https://source.android.com/devices/tech/debug/tagged-pointers">Tagged
+     * Pointers</a>
+     */
+    @ChangeId
+    @EnabledAfter(targetSdkVersion = VersionCodes.Q)
+    private static final long NATIVE_HEAP_POINTER_TAGGING = 135754954; // This is a bug id.
+
     ActivityManagerService mService = null;
 
     // To kill process groups asynchronously
@@ -1653,6 +1666,10 @@ public final class ProcessList {
                 runtimeFlags |= Zygote.USE_APP_IMAGE_STARTUP_CACHE;
             }
 
+            if (mPlatformCompat.isChangeEnabled(NATIVE_HEAP_POINTER_TAGGING, app.info)) {
+                runtimeFlags |= Zygote.MEMORY_TAG_LEVEL_TBI;
+            }
+
             String invokeWith = null;
             if ((app.info.flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0) {
                 // Debuggable apps may include a wrapper script with their library directory.