Snap for 9352282 from 7e2a46ab9b8c31bd51eccd2f5ba296a27aff9133 to mainline-adservices-releaseaml_ads_331511020aml_ads_331418080

Change-Id: If5acb5d7b946119bb3f711ada900d5999cff6cec

21 files changed, 125 insertions, 137 deletions

diff --git a/build/art.go b/build/art.go
index 6fb5a65c06..6014148d5f 100644
--- a/build/art.go
+++ b/build/art.go
@@ -70,10 +70,11 @@ func globalFlags(ctx android.LoadHookContext) ([]string, []string) {
 		if !ctx.Config().IsEnvFalse("ART_USE_GENERATIONAL_CC") {
 			cflags = append(cflags, "-DART_USE_GENERATIONAL_CC=1")
 		}
-		// For now force CC as we don't want to make userfaultfd GC the default.
-		// Eventually, make it such that we force CC only if ART_USE_READ_BARRIER
-		// was set to true explicitly during build time.
-		cflags = append(cflags, "-DART_FORCE_USE_READ_BARRIER=1")
+		// Force CC only if ART_USE_READ_BARRIER was set to true explicitly during
+		// build time.
+		if ctx.Config().IsEnvTrue("ART_USE_READ_BARRIER") {
+			cflags = append(cflags, "-DART_FORCE_USE_READ_BARRIER=1")
+		}
 		tlab = true
 	} else if gcType == "CMC" {
 		tlab = true
diff --git a/dex2oat/linker/image_test.h b/dex2oat/linker/image_test.h
index b570d99e64..39ce4d7804 100644
--- a/dex2oat/linker/image_test.h
+++ b/dex2oat/linker/image_test.h
@@ -50,6 +50,7 @@
 #include "mirror/object-inl.h"
 #include "oat.h"
 #include "oat_writer.h"
+#include "read_barrier_config.h"
 #include "scoped_thread_state_change-inl.h"
 #include "signal_catcher.h"
 #include "stream/buffered_output_stream.h"
@@ -229,6 +230,8 @@ inline void ImageTest::DoCompile(ImageHeader::StorageMode storage_mode,
       key_value_store.Put(OatHeader::kBootClassPathKey,
                           android::base::Join(out_helper.dex_file_locations, ':'));
       key_value_store.Put(OatHeader::kApexVersionsKey, Runtime::Current()->GetApexVersions());
+      key_value_store.Put(OatHeader::kConcurrentCopying,
+                          gUseReadBarrier ? OatHeader::kTrueValue : OatHeader::kFalseValue);
 
       std::vector<std::unique_ptr<ElfWriter>> elf_writers;
       std::vector<std::unique_ptr<OatWriter>> oat_writers;
diff --git a/libnativeloader/library_namespaces.cpp b/libnativeloader/library_namespaces.cpp
index f3c93a0ecc..bcc19aaa41 100644
--- a/libnativeloader/library_namespaces.cpp
+++ b/libnativeloader/library_namespaces.cpp
@@ -85,18 +85,15 @@ constexpr const char* kVendorLibPath = "/vendor/" LIB;
 // below, because they can't be two separate directories - either one has to be
 // a symlink to the other.
 constexpr const char* kProductLibPath = "/product/" LIB ":/system/product/" LIB;
-constexpr const char* kSystemLibPath = "/system/" LIB ":/system_ext/" LIB;
 
 const std::regex kVendorDexPathRegex("(^|:)(/system)?/vendor/");
 const std::regex kProductDexPathRegex("(^|:)(/system)?/product/");
-const std::regex kSystemDexPathRegex("(^|:)/system(_ext)?/");  // MUST be tested last.
 
-// Define origin partition of APK
+// Define origin of APK if it is from vendor partition or product partition
 using ApkOrigin = enum {
   APK_ORIGIN_DEFAULT = 0,
   APK_ORIGIN_VENDOR = 1,   // Includes both /vendor and /system/vendor
   APK_ORIGIN_PRODUCT = 2,  // Includes both /product and /system/product
-  APK_ORIGIN_SYSTEM = 3,   // Includes both /system and /system_ext but not /system/{vendor,product}
 };
 
 jobject GetParentClassLoader(JNIEnv* env, jobject class_loader) {
@@ -119,9 +116,6 @@ ApkOrigin GetApkOriginFromDexPath(const std::string& dex_path) {
 
     apk_origin = APK_ORIGIN_PRODUCT;
   }
-  if (apk_origin == APK_ORIGIN_DEFAULT && std::regex_search(dex_path, kSystemDexPathRegex)) {
-    apk_origin = APK_ORIGIN_SYSTEM;
-  }
   return apk_origin;
 }
 
@@ -243,18 +237,7 @@ Result<NativeLoaderNamespace*> LibraryNamespaces::Create(JNIEnv* env, uint32_t t
   const char* apk_origin_msg = "other apk";  // Only for debug logging.
 
   if (!is_shared) {
-    if (apk_origin == APK_ORIGIN_SYSTEM) {
-      // System apps commonly get shared namespaces and hence don't need this.
-      // In practice it's necessary for shared system libraries (i.e. JARs
-      // rather than actual APKs) that are loaded by ordinary apps which don't
-      // get shared namespaces.
-      apk_origin_msg = "system apk";
-
-      // Give access to all libraries in the system and system_ext partitions
-      // (they can freely access each other's private APIs).
-      library_path = library_path + ":" + kSystemLibPath;
-      permitted_path = permitted_path + ":" + kSystemLibPath;
-    } else if (apk_origin == APK_ORIGIN_VENDOR) {
+    if (apk_origin == APK_ORIGIN_VENDOR) {
       unbundled_app_origin = APK_ORIGIN_VENDOR;
       apk_origin_msg = "unbundled vendor apk";
 
@@ -308,7 +291,8 @@ Result<NativeLoaderNamespace*> LibraryNamespaces::Create(JNIEnv* env, uint32_t t
     // they are to other apps, including those in system, system_ext, and
     // product partitions. The reason is that when GSI is used, the system
     // partition may get replaced, and then vendor apps may fail. It's fine for
-    // product apps, because that partition isn't mounted in GSI tests.
+    // product (and system_ext) apps, because those partitions aren't mounted in
+    // GSI tests.
     auto libs =
         filter_public_libraries(target_sdk_version, uses_libraries, extended_public_libraries());
     if (!libs.empty()) {
diff --git a/libnativeloader/test/Android.bp b/libnativeloader/test/Android.bp
index 1d3a07a5f3..b43a02ce4a 100644
--- a/libnativeloader/test/Android.bp
+++ b/libnativeloader/test/Android.bp
@@ -55,13 +55,6 @@ java_library {
     srcs: ["src/android/test/systemsharedlib/SystemSharedLib.java"],
 }
 
-// Test fixture that represents a shared library in /system_ext/framework.
-java_library {
-    name: "libnativeloader_system_ext_shared_lib",
-    installable: true,
-    srcs: ["src/android/test/systemextsharedlib/SystemExtSharedLib.java"],
-}
-
 java_defaults {
     name: "loadlibrarytest_app_defaults",
     defaults: ["art_module_source_build_java_defaults"],
@@ -70,10 +63,7 @@ java_defaults {
         "androidx.test.rules",
         "loadlibrarytest_test_utils",
     ],
-    libs: [
-        "libnativeloader_system_shared_lib",
-        "libnativeloader_system_ext_shared_lib",
-    ],
+    libs: ["libnativeloader_system_shared_lib"],
 }
 
 android_test_helper_app {
@@ -135,7 +125,6 @@ java_test_host {
     data: [
         ":library_container_app",
         ":libnativeloader_system_shared_lib",
-        ":libnativeloader_system_ext_shared_lib",
         ":loadlibrarytest_system_priv_app",
         ":loadlibrarytest_system_app",
         ":loadlibrarytest_system_ext_app",
diff --git a/libnativeloader/test/loadlibrarytest_data_app_manifest.xml b/libnativeloader/test/loadlibrarytest_data_app_manifest.xml
index 2af0af417e..9b663e6d94 100644
--- a/libnativeloader/test/loadlibrarytest_data_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_data_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.data" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <uses-native-library android:required="false" android:name="libfoo.oem1.so" />
         <uses-native-library android:required="false" android:name="libbar.oem1.so" />
         <uses-native-library android:required="false" android:name="libfoo.oem2.so" />
diff --git a/libnativeloader/test/loadlibrarytest_product_app_manifest.xml b/libnativeloader/test/loadlibrarytest_product_app_manifest.xml
index 614f33ffc9..c1d997aa70 100644
--- a/libnativeloader/test/loadlibrarytest_product_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_product_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.product" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <uses-native-library android:required="false" android:name="libfoo.oem1.so" />
         <uses-native-library android:required="false" android:name="libbar.oem1.so" />
         <uses-native-library android:required="false" android:name="libfoo.oem2.so" />
diff --git a/libnativeloader/test/loadlibrarytest_system_app_manifest.xml b/libnativeloader/test/loadlibrarytest_system_app_manifest.xml
index 5711f651cf..5c6af09031 100644
--- a/libnativeloader/test/loadlibrarytest_system_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_system_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.system" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <!-- System apps get a shared classloader namespace, so they don't need
              uses-native-library entries for anything in /system. -->
         <uses-native-library android:required="false" android:name="libfoo.product1.so" />
diff --git a/libnativeloader/test/loadlibrarytest_system_ext_app_manifest.xml b/libnativeloader/test/loadlibrarytest_system_ext_app_manifest.xml
index 8aa3fa9f1f..961f9ba389 100644
--- a/libnativeloader/test/loadlibrarytest_system_ext_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_system_ext_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.system_ext" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <!-- System apps get a shared classloader namespace, so they don't need
              uses-native-library entries for anything in /system. -->
         <uses-native-library android:required="false" android:name="libfoo.product1.so" />
diff --git a/libnativeloader/test/loadlibrarytest_system_priv_app_manifest.xml b/libnativeloader/test/loadlibrarytest_system_priv_app_manifest.xml
index 126453c86f..f4bf3c094b 100644
--- a/libnativeloader/test/loadlibrarytest_system_priv_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_system_priv_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.system_priv" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <!-- System apps get a shared classloader namespace, so they don't need
              uses-native-library entries for anything in /system. -->
         <uses-native-library android:required="false" android:name="libfoo.product1.so" />
diff --git a/libnativeloader/test/loadlibrarytest_vendor_app_manifest.xml b/libnativeloader/test/loadlibrarytest_vendor_app_manifest.xml
index a2a9f648f4..1a8cbcc2a8 100644
--- a/libnativeloader/test/loadlibrarytest_vendor_app_manifest.xml
+++ b/libnativeloader/test/loadlibrarytest_vendor_app_manifest.xml
@@ -21,7 +21,6 @@
                      android:targetPackage="android.test.app.vendor" />
     <application>
         <uses-library android:name="android.test.systemsharedlib" />
-        <uses-library android:name="android.test.systemextsharedlib" />
         <uses-native-library android:required="false" android:name="libfoo.oem1.so" />
         <uses-native-library android:required="false" android:name="libbar.oem1.so" />
         <uses-native-library android:required="false" android:name="libfoo.oem2.so" />
diff --git a/libnativeloader/test/src/android/test/app/DataAppTest.java b/libnativeloader/test/src/android/test/app/DataAppTest.java
index 767a7b19ff..db97e8ddc0 100644
--- a/libnativeloader/test/src/android/test/app/DataAppTest.java
+++ b/libnativeloader/test/src/android/test/app/DataAppTest.java
@@ -17,7 +17,6 @@
 package android.test.app;
 
 import android.test.lib.TestUtils;
-import android.test.systemextsharedlib.SystemExtSharedLib;
 import android.test.systemsharedlib.SystemSharedLib;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -41,24 +40,16 @@ public class DataAppTest {
     @Test
     public void testLoadPrivateLibraries() {
         TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("system_private1"));
-        TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("systemext_private1"));
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("product_private1"));
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("vendor_private1"));
     }
 
     @Test
     public void testLoadPrivateLibrariesViaSystemSharedLib() {
-        SystemSharedLib.loadLibrary("system_private2");
-        SystemSharedLib.loadLibrary("systemext_private2");
+        // TODO(b/237577392): Fix this use case.
+        TestUtils.assertLinkerNamespaceError(() -> SystemSharedLib.loadLibrary("system_private2"));
+
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("product_private2"));
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("vendor_private2"));
     }
-
-    @Test
-    public void testLoadPrivateLibrariesViaSystemExtSharedLib() {
-        SystemExtSharedLib.loadLibrary("system_private3");
-        SystemExtSharedLib.loadLibrary("systemext_private3");
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("product_private3"));
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("vendor_private3"));
-    }
 }
diff --git a/libnativeloader/test/src/android/test/app/ProductAppTest.java b/libnativeloader/test/src/android/test/app/ProductAppTest.java
index 1f36798515..a9b8697067 100644
--- a/libnativeloader/test/src/android/test/app/ProductAppTest.java
+++ b/libnativeloader/test/src/android/test/app/ProductAppTest.java
@@ -17,7 +17,6 @@
 package android.test.app;
 
 import android.test.lib.TestUtils;
-import android.test.systemextsharedlib.SystemExtSharedLib;
 import android.test.systemsharedlib.SystemSharedLib;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -41,24 +40,16 @@ public class ProductAppTest {
     @Test
     public void testLoadPrivateLibraries() {
         TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("system_private1"));
-        TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("systemext_private1"));
         System.loadLibrary("product_private1");
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("vendor_private1"));
     }
 
     @Test
     public void testLoadPrivateLibrariesViaSystemSharedLib() {
-        SystemSharedLib.loadLibrary("system_private2");
-        SystemSharedLib.loadLibrary("systemext_private2");
+        // TODO(b/237577392): Fix this use case.
+        TestUtils.assertLinkerNamespaceError(() -> SystemSharedLib.loadLibrary("system_private2"));
+
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("product_private2"));
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("vendor_private2"));
     }
-
-    @Test
-    public void testLoadPrivateLibrariesViaSystemExtSharedLib() {
-        SystemExtSharedLib.loadLibrary("system_private3");
-        SystemExtSharedLib.loadLibrary("systemext_private3");
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("product_private3"));
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("vendor_private3"));
-    }
 }
diff --git a/libnativeloader/test/src/android/test/app/SystemAppTest.java b/libnativeloader/test/src/android/test/app/SystemAppTest.java
index 197a40cf0e..664447824c 100644
--- a/libnativeloader/test/src/android/test/app/SystemAppTest.java
+++ b/libnativeloader/test/src/android/test/app/SystemAppTest.java
@@ -17,7 +17,6 @@
 package android.test.app;
 
 import android.test.lib.TestUtils;
-import android.test.systemextsharedlib.SystemExtSharedLib;
 import android.test.systemsharedlib.SystemSharedLib;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -41,7 +40,6 @@ public class SystemAppTest {
     @Test
     public void testLoadPrivateLibraries() {
         System.loadLibrary("system_private1");
-        System.loadLibrary("systemext_private1");
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("product_private1"));
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("vendor_private1"));
     }
@@ -49,16 +47,7 @@ public class SystemAppTest {
     @Test
     public void testLoadPrivateLibrariesViaSystemSharedLib() {
         SystemSharedLib.loadLibrary("system_private2");
-        SystemSharedLib.loadLibrary("systemext_private2");
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("product_private2"));
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("vendor_private2"));
     }
-
-    @Test
-    public void testLoadPrivateLibrariesViaSystemExtSharedLib() {
-        SystemExtSharedLib.loadLibrary("system_private3");
-        SystemExtSharedLib.loadLibrary("systemext_private3");
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("product_private3"));
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("vendor_private3"));
-    }
 }
diff --git a/libnativeloader/test/src/android/test/app/VendorAppTest.java b/libnativeloader/test/src/android/test/app/VendorAppTest.java
index c9ce8db57a..5187ac8c20 100644
--- a/libnativeloader/test/src/android/test/app/VendorAppTest.java
+++ b/libnativeloader/test/src/android/test/app/VendorAppTest.java
@@ -17,7 +17,6 @@
 package android.test.app;
 
 import android.test.lib.TestUtils;
-import android.test.systemextsharedlib.SystemExtSharedLib;
 import android.test.systemsharedlib.SystemSharedLib;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -40,7 +39,6 @@ public class VendorAppTest {
     @Test
     public void testLoadPrivateLibraries() {
         TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("system_private1"));
-        TestUtils.assertLinkerNamespaceError(() -> System.loadLibrary("systemext_private1"));
         TestUtils.assertLibraryNotFound(() -> System.loadLibrary("product_private1"));
         // TODO(mast): The vendor app fails to load a private vendor library because it gets
         // classified as untrusted_app in SELinux, which doesn't have access to vendor_file. Even an
@@ -51,17 +49,10 @@ public class VendorAppTest {
 
     @Test
     public void testLoadPrivateLibrariesViaSystemSharedLib() {
-        SystemSharedLib.loadLibrary("system_private2");
-        SystemSharedLib.loadLibrary("systemext_private2");
+        // TODO(b/237577392): Fix this use case.
+        TestUtils.assertLinkerNamespaceError(() -> SystemSharedLib.loadLibrary("system_private2"));
+
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("product_private2"));
         TestUtils.assertLibraryNotFound(() -> SystemSharedLib.loadLibrary("vendor_private2"));
     }
-
-    @Test
-    public void testLoadPrivateLibrariesViaSystemExtSharedLib() {
-        SystemExtSharedLib.loadLibrary("system_private3");
-        SystemExtSharedLib.loadLibrary("systemext_private3");
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("product_private3"));
-        TestUtils.assertLibraryNotFound(() -> SystemExtSharedLib.loadLibrary("vendor_private3"));
-    }
 }
diff --git a/libnativeloader/test/src/android/test/hostside/LibnativeloaderTest.java b/libnativeloader/test/src/android/test/hostside/LibnativeloaderTest.java
index c9290377ee..c908a492e2 100644
--- a/libnativeloader/test/src/android/test/hostside/LibnativeloaderTest.java
+++ b/libnativeloader/test/src/android/test/hostside/LibnativeloaderTest.java
@@ -69,10 +69,7 @@ public class LibnativeloaderTest extends BaseHostJUnit4Test {
             ctx.pushExtendedPublicProductLibs(libApk);
             ctx.pushPrivateLibs(libApk);
         }
-        ctx.pushSystemSharedLib("/system/framework", "android.test.systemsharedlib",
-                "libnativeloader_system_shared_lib.jar");
-        ctx.pushSystemSharedLib("/system_ext/framework", "android.test.systemextsharedlib",
-                "libnativeloader_system_ext_shared_lib.jar");
+        ctx.pushSystemSharedLib();
 
         // "Install" apps in various partitions through plain adb push followed by a soft reboot. We
         // need them in these locations to test library loading restrictions, so for all except
@@ -233,18 +230,17 @@ public class LibnativeloaderTest extends BaseHostJUnit4Test {
         void pushPrivateLibs(ZipFile libApk) throws Exception {
             // Push the libraries once for each test. Since we cannot unload them, we need a fresh
             // never-before-loaded library in each loadLibrary call.
-            for (int i = 1; i <= 3; ++i) {
+            for (int i = 1; i <= 2; ++i) {
                 pushNativeTestLib(libApk, "/system/${LIB}/libsystem_private" + i + ".so");
-                pushNativeTestLib(libApk, "/system_ext/${LIB}/libsystemext_private" + i + ".so");
                 pushNativeTestLib(libApk, "/product/${LIB}/libproduct_private" + i + ".so");
                 pushNativeTestLib(libApk, "/vendor/${LIB}/libvendor_private" + i + ".so");
             }
         }
 
-        void pushSystemSharedLib(String packageDir, String packageName, String buildJarName)
-                throws Exception {
-            String path = packageDir + "/" + packageName + ".jar";
-            pushFile(buildJarName, path);
+        void pushSystemSharedLib() throws Exception {
+            String packageName = "android.test.systemsharedlib";
+            String path = "/system/framework/" + packageName + ".jar";
+            pushFile("libnativeloader_system_shared_lib.jar", path);
             pushString("<permissions>\n"
                             + "<library name=\"" + packageName + "\" file=\"" + path + "\" />\n"
                             + "</permissions>\n",
diff --git a/libnativeloader/test/src/android/test/systemextsharedlib/SystemExtSharedLib.java b/libnativeloader/test/src/android/test/systemextsharedlib/SystemExtSharedLib.java
deleted file mode 100644
index 1240e12e55..0000000000
--- a/libnativeloader/test/src/android/test/systemextsharedlib/SystemExtSharedLib.java
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Copyright (C) 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package android.test.systemextsharedlib;
-
-public final class SystemExtSharedLib {
-    public static void loadLibrary(String name) { System.loadLibrary(name); }
-}
diff --git a/runtime/exec_utils.cc b/runtime/exec_utils.cc
index dd389f8c97..58ee5ce01e 100644
--- a/runtime/exec_utils.cc
+++ b/runtime/exec_utils.cc
@@ -16,9 +16,11 @@
 
 #include "exec_utils.h"
 
+#include <errno.h>
 #include <poll.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sysexits.h>
 #include <unistd.h>
 
 #include <ctime>
@@ -89,6 +91,12 @@ pid_t ExecWithoutWait(const std::vector<std::string>& arg_vector, std::string* e
     } else {
       execve(program, &args[0], envp);
     }
+    if (errno == EACCES) {
+      // This usually happens when a non-Zygote process invokes dex2oat to generate an in-memory
+      // boot image, which is WAI.
+      PLOG(DEBUG) << "Failed to execute (" << ToCommandLine(arg_vector) << ")";
+      _exit(EX_NOPERM);
+    }
     // This should be regarded as a crash rather than a normal return.
     PLOG(FATAL) << "Failed to execute (" << ToCommandLine(arg_vector) << ")";
     UNREACHABLE();
diff --git a/runtime/exec_utils_test.cc b/runtime/exec_utils_test.cc
index e89180b572..a435e3c8fe 100644
--- a/runtime/exec_utils_test.cc
+++ b/runtime/exec_utils_test.cc
@@ -17,6 +17,7 @@
 #include "exec_utils.h"
 
 #include <sys/utsname.h>
+#include <sysexits.h>
 
 #include <csignal>
 #include <cstring>
@@ -127,6 +128,15 @@ TEST_P(ExecUtilsTest, ExecError) {
   EXPECT_FALSE(error_msg.empty());
 }
 
+TEST_P(ExecUtilsTest, ExecPermissionDenied) {
+  std::vector<std::string> command;
+  command.push_back("/dev/null");
+  std::string error_msg;
+  ExecResult result = exec_utils_->ExecAndReturnResult(command, /*timeout_sec=*/-1, &error_msg);
+  EXPECT_EQ(result.status, ExecResult::kExited);
+  EXPECT_EQ(result.exit_code, EX_NOPERM);
+}
+
 TEST_P(ExecUtilsTest, EnvSnapshotAdditionsAreNotVisible) {
   static constexpr const char* kModifiedVariable = "EXEC_SHOULD_NOT_EXPORT_THIS";
   static constexpr int kOverwrite = 1;
diff --git a/runtime/gc/collector/mark_compact.cc b/runtime/gc/collector/mark_compact.cc
index d73418b8b3..71e5a13638 100644
--- a/runtime/gc/collector/mark_compact.cc
+++ b/runtime/gc/collector/mark_compact.cc
@@ -16,10 +16,13 @@
 
 #include "mark_compact-inl.h"
 
+#include "android-base/file.h"
+#include "android-base/properties.h"
 #include "base/quasi_atomic.h"
 #include "base/systrace.h"
 #include "base/utils.h"
 #include "gc/accounting/mod_union_table-inl.h"
+#include "gc/collector_type.h"
 #include "gc/reference_processor.h"
 #include "gc/space/bump_pointer_space.h"
 #include "gc/task_processor.h"
@@ -36,6 +39,7 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <unistd.h>
+
 #include <fstream>
 #include <numeric>
 
@@ -58,6 +62,12 @@
 #endif  // __NR_userfaultfd
 #endif  // __BIONIC__
 
+namespace {
+
+using ::android::base::GetBoolProperty;
+
+}
+
 namespace art {
 
 // We require MREMAP_DONTUNMAP functionality of the mremap syscall, which was
@@ -82,11 +92,28 @@ static bool gHaveMremapDontunmap = IsKernelVersionAtLeast(5, 13) || HaveMremapDo
 // userfaultfd is enabled.
 static const bool gKernelHasFaultRetry = kIsTargetAndroid || IsKernelVersionAtLeast(5, 7);
 
-#ifndef ART_FORCE_USE_READ_BARRIER
-static bool ShouldUseUserfaultfd() {
-#if !defined(__linux__)
-  return false;
-#endif
+// The other cases are defined as constexpr in runtime/read_barrier_config.h
+#if !defined(ART_FORCE_USE_READ_BARRIER) && defined(ART_USE_READ_BARRIER)
+// Returns collector type asked to be used on the cmdline.
+static gc::CollectorType FetchCmdlineGcType() {
+  std::string argv;
+  gc::CollectorType gc_type = gc::CollectorType::kCollectorTypeNone;
+  if (android::base::ReadFileToString("/proc/self/cmdline", &argv)) {
+    if (argv.find("-Xgc:CMC") != std::string::npos) {
+      gc_type = gc::CollectorType::kCollectorTypeCMC;
+    } else if (argv.find("-Xgc:CC") != std::string::npos) {
+      gc_type = gc::CollectorType::kCollectorTypeCC;
+    }
+  }
+  return gc_type;
+}
+
+static bool SysPropSaysUffdGc() {
+  return GetBoolProperty("persist.device_config.runtime_native_boot.enable_uffd_gc",
+                         GetBoolProperty("ro.dalvik.vm.enable_uffd_gc", false));
+}
+
+static bool KernelSupportsUffd() {
   int fd = syscall(__NR_userfaultfd, O_CLOEXEC | UFFD_USER_MODE_ONLY);
   // On non-android devices we may not have the kernel patches that restrict
   // userfaultfd to user mode. But that is not a security concern as we are
@@ -101,15 +128,26 @@ static bool ShouldUseUserfaultfd() {
     return false;
   }
 }
-#endif
 
-// The other cases are defined as a constexpr in runtime/read_barrier_config.h
-#ifndef ART_FORCE_USE_READ_BARRIER
-const bool gUseReadBarrier = (kUseBakerReadBarrier || kUseTableLookupReadBarrier)
-                             && !ShouldUseUserfaultfd();
-#ifdef ART_DEFAULT_GC_TYPE_IS_CMC
-const bool gUseUserfaultfd = !gUseReadBarrier;
+static bool ShouldUseUserfaultfd() {
+  static_assert(kUseBakerReadBarrier || kUseTableLookupReadBarrier);
+#ifdef __linux__
+  // Use CMC/CC if that is being explicitly asked for on cmdline. Otherwise,
+  // always use CC on host. On target, use CMC only if system properties says so
+  // and the kernel supports it.
+  gc::CollectorType gc_type = FetchCmdlineGcType();
+  return gc_type == gc::CollectorType::kCollectorTypeCMC ||
+         (gc_type == gc::CollectorType::kCollectorTypeNone &&
+          kIsTargetAndroid &&
+          SysPropSaysUffdGc() &&
+          KernelSupportsUffd());
+#else
+  return false;
 #endif
+}
+
+const bool gUseUserfaultfd = ShouldUseUserfaultfd();
+const bool gUseReadBarrier = !gUseUserfaultfd;
 #endif
 
 namespace gc {
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index 4deb089349..5eee76b939 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -49,6 +49,7 @@
 #include "dex/art_dex_file_loader.h"
 #include "dex/dex_file_loader.h"
 #include "exec_utils.h"
+#include "fmt/format.h"
 #include "gc/accounting/space_bitmap-inl.h"
 #include "gc/task_processor.h"
 #include "image-inl.h"
@@ -69,14 +70,20 @@ namespace art {
 namespace gc {
 namespace space {
 
-using android::base::Join;
-using android::base::StringAppendF;
-using android::base::StringPrintf;
+namespace {
+
+using ::android::base::Join;
+using ::android::base::StringAppendF;
+using ::android::base::StringPrintf;
+
+using ::fmt::literals::operator""_format;  // NOLINT
 
 // We do not allow the boot image and extensions to take more than 1GiB. They are
 // supposed to be much smaller and allocating more that this would likely fail anyway.
 static constexpr size_t kMaxTotalImageReservationSize = 1 * GB;
 
+}  // namespace
+
 Atomic<uint32_t> ImageSpace::bitmap_index_(0);
 
 ImageSpace::ImageSpace(const std::string& image_filename,
@@ -3583,6 +3590,15 @@ bool ImageSpace::ValidateOatFile(const OatFile& oat_file,
     return false;
   }
 
+  // For a boot image, the key value store only exists in the first OAT file. Skip other OAT files.
+  if (oat_file.GetOatHeader().GetKeyValueStoreSize() != 0 &&
+      oat_file.GetOatHeader().IsConcurrentCopying() != gUseReadBarrier) {
+    *error_msg =
+        "ValidateOatFile found read barrier state mismatch (oat file: {}, runtime: {})"_format(
+            oat_file.GetOatHeader().IsConcurrentCopying(), gUseReadBarrier);
+    return false;
+  }
+
   const ArtDexFileLoader dex_file_loader;
   size_t dex_file_index = 0;
   for (const OatDexFile* oat_dex_file : oat_file.GetOatDexFiles()) {
diff --git a/runtime/read_barrier_config.h b/runtime/read_barrier_config.h
index 53274eacf0..876e3d7d15 100644
--- a/runtime/read_barrier_config.h
+++ b/runtime/read_barrier_config.h
@@ -71,16 +71,24 @@ static constexpr bool kUseTableLookupReadBarrier = true;
 static constexpr bool kUseTableLookupReadBarrier = false;
 #endif
 
+// Only if read-barrier isn't forced (see build/art.go) but is selected, that we need
+// to see if we support userfaultfd GC. All the other cases can be constexpr here.
 #ifdef ART_FORCE_USE_READ_BARRIER
 constexpr bool gUseReadBarrier = kUseBakerReadBarrier || kUseTableLookupReadBarrier;
 constexpr bool gUseUserfaultfd = !gUseReadBarrier;
+static_assert(!gUseUserfaultfd);
 #else
-extern const bool gUseReadBarrier;
+#ifndef ART_USE_READ_BARRIER
+constexpr bool gUseReadBarrier = false;
 #ifdef ART_DEFAULT_GC_TYPE_IS_CMC
-extern const bool gUseUserfaultfd;
+constexpr bool gUseUserfaultfd = true;
 #else
 constexpr bool gUseUserfaultfd = false;
 #endif
+#else
+extern const bool gUseReadBarrier;
+extern const bool gUseUserfaultfd;
+#endif
 #endif
 
 // Disabled for performance reasons.