diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -736,15 +736,25 @@
 
 static int getMemtagMode(opt::InputArgList &args) {
   StringRef memtagModeArg = args.getLastArgValue(OPT_android_memtag_mode);
+
+  if (memtagModeArg.empty()) {
+    if (config->androidMemtagStack)
+      warn("--android-memtag-mode is unspecified, leaving "
+           "--android-memtag-stack a no-op");
+    else if (config->androidMemtagHeap)
+      warn("--android-memtag-mode is unspecified, leaving "
+           "--android-memtag-heap a no-op");
+    return ELF::NT_MEMTAG_LEVEL_NONE;
+  }
+
   if (!config->androidMemtagHeap && !config->androidMemtagStack) {
-    if (!memtagModeArg.empty())
-      error("when using --android-memtag-mode, at least one of "
-            "--android-memtag-heap or "
-            "--android-memtag-stack is required");
+    error("when using --android-memtag-mode, at least one of "
+          "--android-memtag-heap or "
+          "--android-memtag-stack is required");
     return ELF::NT_MEMTAG_LEVEL_NONE;
   }
 
-  if (memtagModeArg == "sync" || memtagModeArg.empty())
+  if (memtagModeArg == "sync")
     return ELF::NT_MEMTAG_LEVEL_SYNC;
   if (memtagModeArg == "async")
     return ELF::NT_MEMTAG_LEVEL_ASYNC;
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -1441,6 +1441,12 @@
       addInt(DT_AARCH64_BTI_PLT, 0);
     if (config->zPacPlt)
       addInt(DT_AARCH64_PAC_PLT, 0);
+
+    if (config->androidMemtagMode != ELF::NT_MEMTAG_LEVEL_NONE) {
+      addInt(DT_AARCH64_MEMTAG_MODE, config->androidMemtagMode == NT_MEMTAG_LEVEL_ASYNC);
+      addInt(DT_AARCH64_MEMTAG_HEAP, config->androidMemtagHeap);
+      addInt(DT_AARCH64_MEMTAG_STACK, config->androidMemtagStack);
+    }
   }
 
   addInSec(DT_SYMTAB, *part.dynSymTab);
@@ -3835,16 +3841,16 @@
 
 constexpr char kMemtagAndroidNoteName[] = "Android";
 void MemtagAndroidNote::writeTo(uint8_t *buf) {
-  static_assert(sizeof(kMemtagAndroidNoteName) == 8,
-                "ABI check for Android 11 & 12.");
-  assert((config->androidMemtagStack || config->androidMemtagHeap) &&
-         "Should only be synthesizing a note if heap || stack is enabled.");
+  static_assert(
+      sizeof(kMemtagAndroidNoteName) == 8,
+      "Android 11 & 12 have an ABI that the note name is 8 bytes long. Keep it "
+      "that way for backwards compatibility.");
 
   write32(buf, sizeof(kMemtagAndroidNoteName));
   write32(buf + 4, sizeof(uint32_t));
   write32(buf + 8, ELF::NT_ANDROID_TYPE_MEMTAG);
   memcpy(buf + 12, kMemtagAndroidNoteName, sizeof(kMemtagAndroidNoteName));
-  buf += 12 + sizeof(kMemtagAndroidNoteName);
+  buf += 12 + alignTo(sizeof(kMemtagAndroidNoteName), 4);
 
   uint32_t value = 0;
   value |= config->androidMemtagMode;
@@ -3859,7 +3865,7 @@
 
 size_t MemtagAndroidNote::getSize() const {
   return sizeof(llvm::ELF::Elf64_Nhdr) +
-         /*namesz=*/sizeof(kMemtagAndroidNoteName) +
+         /*namesz=*/alignTo(sizeof(kMemtagAndroidNoteName), 4) +
          /*descsz=*/sizeof(uint32_t);
 }
 
diff --git a/lld/test/ELF/aarch64-memtag-android-abi.s b/lld/test/ELF/aarch64-memtag-android-abi.s
--- a/lld/test/ELF/aarch64-memtag-android-abi.s
+++ b/lld/test/ELF/aarch64-memtag-android-abi.s
@@ -6,56 +6,58 @@
 ## can be run on these versions of Android.
 
 # RUN: llvm-mc --filetype=obj -triple=aarch64-none-linux-android %s -o %t.o
-# RUN: ld.lld --android-memtag-mode=async --android-memtag-heap %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,NOSTACK,ASYNC
+# RUN: ld.lld -shared --android-memtag-mode=async --android-memtag-heap %t.o -o %t
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,HEAP,NOSTACK,ASYNC
 
-# RUN: ld.lld --android-memtag-mode=sync --android-memtag-heap %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,NOSTACK,SYNC
+# RUN: ld.lld -shared --android-memtag-mode=sync --android-memtag-heap %t.o -o %t
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,HEAP,NOSTACK,SYNC
 
-# RUN: ld.lld --android-memtag-mode=async --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,NOHEAP,STACK,ASYNC
+# RUN: ld.lld -shared --android-memtag-mode=async --android-memtag-stack %t.o -o %t
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,NOHEAP,STACK,ASYNC
 
-# RUN: ld.lld --android-memtag-mode=sync --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,NOHEAP,STACK,SYNC
+# RUN: ld.lld -shared --android-memtag-mode=sync --android-memtag-stack %t.o -o %t
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,NOHEAP,STACK,SYNC
 
-# RUN: ld.lld --android-memtag-mode=async --android-memtag-heap \
+# RUN: ld.lld -shared --android-memtag-mode=async --android-memtag-heap \
 # RUN:    --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,STACK,ASYNC
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,HEAP,STACK,ASYNC
 
-# RUN: ld.lld --android-memtag-mode=sync --android-memtag-heap \
+# RUN: ld.lld -shared --android-memtag-mode=sync --android-memtag-heap \
 # RUN:    --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,STACK,SYNC
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=CHECK,HEAP,STACK,SYNC
 
-# RUN: ld.lld --android-memtag-heap %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,NOSTACK,SYNC
+# RUN: ld.lld -shared --android-memtag-heap %t.o -o %t 2>&1 | \
+# RUN:    FileCheck %s --check-prefixes=MISSING-MODE
+# RUN: ld.lld -shared --android-memtag-stack %t.o -o %t 2>&1 | \
+# RUN:    FileCheck %s --check-prefixes=MISSING-MODE
+# RUN: ld.lld -shared --android-memtag-heap --android-memtag-stack %t.o -o %t 2>&1 | \
+# RUN:    FileCheck %s --check-prefixes=MISSING-MODE
+# MISSING-MODE: --android-memtag-mode is unspecified, leaving --android-memtag-{{(heap|stack)}} a no-op
 
-# RUN: ld.lld --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,NOHEAP,STACK,SYNC
+# CHECK: Memtag Dynamic Entries
+# SYNC:    AARCH64_MEMTAG_MODE: Synchronous (0)
+# ASYNC:   AARCH64_MEMTAG_MODE: Asynchronous (1)
+# HEAP:    AARCH64_MEMTAG_HEAP: Enabled (1)
+# NOHEAP:  AARCH64_MEMTAG_HEAP: Disabled (0)
+# STACK:   AARCH64_MEMTAG_STACK: Enabled (1)
+# NOSTACK: AARCH64_MEMTAG_STACK: Disabled (0)
 
-# RUN: ld.lld --android-memtag-heap --android-memtag-stack %t.o -o %t
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,HEAP,STACK,SYNC
-
-# NOTE: .note.android.memtag
-# NOTE-NEXT: Owner
-# NOTE-NEXT: Android 0x00000004 NT_ANDROID_TYPE_MEMTAG (Android memory tagging
-# NOTE-SAME: information)
-# ASYNC-NEXT: Tagging Mode: ASYNC
-# SYNC-NEXT: Tagging Mode: SYNC
-# HEAP-NEXT: Heap: Enabled
+# CHECK:       Memtag Android Note
+# ASYNC-NEXT:  Tagging Mode: ASYNC
+# SYNC-NEXT:   Tagging Mode: SYNC
+# HEAP-NEXT:   Heap: Enabled
 # NOHEAP-NEXT: Heap: Disabled
-## As of Android 12, stack MTE is unimplemented. However, we pre-emptively emit
-## a bit that signifies to the dynamic loader to map the primary and thread
-## stacks as PROT_MTE, in preparation for the bionic support.
 # STACK-NEXT:   Stack: Enabled
 # NOSTACK-NEXT: Stack: Disabled
 
-# RUN: not ld.lld --android-memtag-mode=asymm --android-memtag-heap 2>&1 | \
+# RUN: not ld.lld -shared --android-memtag-mode=asymm --android-memtag-heap 2>&1 | \
 # RUN:    FileCheck %s --check-prefix=BAD-MODE
 # BAD-MODE: unknown --android-memtag-mode value: "asymm", should be one of {async, sync, none}
 
-# RUN: not ld.lld --android-memtag-mode=async 2>&1 | \
+# RUN: not ld.lld -shared --android-memtag-mode=async 2>&1 | \
 # RUN:    FileCheck %s --check-prefix=MISSING-STACK-OR-HEAP
-# MISSING-STACK-OR-HEAP: when using --android-memtag-mode, at least one of --android-memtag-heap or --android-memtag-stack is required
+# MISSING-STACK-OR-HEAP:      when using --android-memtag-mode, at least one of
+# MISSING-STACK-OR-HEAP-SAME: --android-memtag-heap or --android-memtag-stack is required
 
 .globl _start
 _start: