diff options
| -rw-r--r-- | core/java/com/android/internal/os/Zygote.java | 7 | ||||
| -rw-r--r-- | core/java/com/android/internal/os/ZygoteInit.java | 16 | ||||
| -rw-r--r-- | core/jni/com_android_internal_os_Zygote.cpp | 32 |
3 files changed, 52 insertions, 3 deletions
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java index 527d10f0d00a..a41018000d77 100644 --- a/core/java/com/android/internal/os/Zygote.java +++ b/core/java/com/android/internal/os/Zygote.java @@ -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(); } diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java index 6335baa97e57..7fde5474ec92 100644 --- a/core/java/com/android/internal/os/ZygoteInit.java +++ b/core/java/com/android/internal/os/ZygoteInit.java @@ -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. */ - parsedArgs.mRuntimeFlags |= Zygote.MEMORY_TAG_LEVEL_ASYNC; + /* 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. */ diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp index d7001d8d36ea..903ecaef4938 100644 --- a/core/jni/com_android_internal_os_Zygote.cpp +++ b/core/jni/com_android_internal_os_Zygote.cpp @@ -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) { |