Merge "[MTE] Parse MTE sysprop in system_server" (4d7b7a71) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/Zygote.java

+7 −0

Original line number	Diff line number	Diff line
		@@ -1096,4 +1096,11 @@ public final class Zygote {
		* fully-feature Memory Tagging, rather than the static Tagged Pointers.
		*/
		public static native boolean nativeSupportsTaggedPointers();

		/**
		* Returns the current native tagging level, as one of the
		* MEMORY_TAG_LEVEL_* constants. Returns zero if no tagging is present, or
		* we failed to determine the level.
		*/
		public static native int nativeCurrentTaggingLevel();
		}

+13 −3

Original line number	Diff line number	Diff line
		@@ -791,9 +791,19 @@ public class ZygoteInit {
		Zygote.applyInvokeWithSystemProperty(parsedArgs);

		if (Zygote.nativeSupportsMemoryTagging()) {
		/* The system server is more privileged than regular app processes, so it has async
		* tag checks enabled on hardware that supports memory tagging. */
		/* The system server has ASYNC MTE by default, in order to allow
		* system services to specify their own MTE level later, as you
		* can't re-enable MTE once it's disabled. */
		String mode = SystemProperties.get("arm64.memtag.process.system_server", "async");
		if (mode.equals("async")) {
		parsedArgs.mRuntimeFlags \|= Zygote.MEMORY_TAG_LEVEL_ASYNC;
		} else if (mode.equals("sync")) {
		parsedArgs.mRuntimeFlags \|= Zygote.MEMORY_TAG_LEVEL_SYNC;
		} else if (!mode.equals("off")) {
		/* When we have an invalid memory tag level, keep the current level. */
		parsedArgs.mRuntimeFlags \|= Zygote.nativeCurrentTaggingLevel();
		Slog.e(TAG, "Unknown memory tag level for the system server: \"" + mode + "\"");
		}
		} else if (Zygote.nativeSupportsTaggedPointers()) {
		/* Enable pointer tagging in the system server. Hardware support for this is present
		* in all ARMv8 CPUs. */

+32 −0

Original line number	Diff line number	Diff line
		@@ -2526,6 +2526,36 @@ static jboolean com_android_internal_os_Zygote_nativeSupportsTaggedPointers(JNIE
		#endif
		}

		static jint com_android_internal_os_Zygote_nativeCurrentTaggingLevel(JNIEnv* env, jclass) {
		#if defined(__aarch64__)
		int level = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
		if (level < 0) {
		ALOGE("Failed to get memory tag level: %s", strerror(errno));
		return 0;
		} else if (!(level & PR_TAGGED_ADDR_ENABLE)) {
		return 0;
		}
		// TBI is only possible on non-MTE hardware.
		if (!mte_supported()) {
		return MEMORY_TAG_LEVEL_TBI;
		}

		switch (level & PR_MTE_TCF_MASK) {
		case PR_MTE_TCF_NONE:
		return 0;
		case PR_MTE_TCF_SYNC:
		return MEMORY_TAG_LEVEL_SYNC;
		case PR_MTE_TCF_ASYNC:
		return MEMORY_TAG_LEVEL_ASYNC;
		default:
		ALOGE("Unknown memory tagging level: %i", level);
		return 0;
		}
		#else // defined(__aarch64__)
		return 0;
		#endif // defined(__aarch64__)
		}

		static const JNINativeMethod gMethods[] = {
		{"nativeForkAndSpecialize",
		"(II[II[[IILjava/lang/String;Ljava/lang/String;[I[IZLjava/lang/String;Ljava/lang/"
		@@ -2565,6 +2595,8 @@ static const JNINativeMethod gMethods[] = {
		(void*)com_android_internal_os_Zygote_nativeSupportsMemoryTagging},
		{"nativeSupportsTaggedPointers", "()Z",
		(void*)com_android_internal_os_Zygote_nativeSupportsTaggedPointers},
		{"nativeCurrentTaggingLevel", "()I",
		(void*)com_android_internal_os_Zygote_nativeCurrentTaggingLevel},
		};

		int register_com_android_internal_os_Zygote(JNIEnv* env) {