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Merge "[MTE] Parse MTE sysprop in system_server" am: 4d7b7a71d6

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Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1575891

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I08b48cb584c9cd727a23457721a50ae4a8b1a2e6
This commit is contained in:
Mitch Phillips
2021-02-08 19:24:28 +00:00
committed by Automerger Merge Worker
parent 808b6d8956 4d7b7a71d6
commit b00646e96c
3 changed files with 52 additions and 3 deletions
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7
core/java/com/android/internal/os/Zygote.java
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@@ -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();
}

16
core/java/com/android/internal/os/ZygoteInit.java
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@@ -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. */

32
core/jni/com_android_internal_os_Zygote.cpp
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@@ -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) {