diff --git a/libc/arch-common/bionic/crtbegin.c b/libc/arch-common/bionic/crtbegin.c
index c4d2a5a..3630b5e 100644
--- a/libc/arch-common/bionic/crtbegin.c
+++ b/libc/arch-common/bionic/crtbegin.c
@@ -63,6 +63,45 @@
 #undef PRE
 #undef POST
 
+// On arm32 and arm64, when targeting Q and up, overalign the TLS segment to
+// (8 * sizeof(void*)), which reserves enough space between the thread pointer
+// and the executable's TLS segment for Bionic's TLS slots. It has the side
+// effect of placing a 0-sized TLS segment into Android executables that don't
+// use TLS, but this should be harmless.
+//
+// To ensure that the .tdata input section isn't deleted, the .text input
+// section (which contains _start) has a relocation to the .tdata input section.
+//
+// TODO: This file currently uses TPREL relocations from .text to ensure that
+// --gc-sections doesn't remove the .tdata input section. The relocations are
+// resolved by the static linker. (They don't appear in the executable.) Replace
+// the TPREL relocations with R_{ARM,AARCH64}_NONE once the toolchain has been
+// updated to support them:
+//  - https://reviews.llvm.org/D61992 (Support .reloc *, R_ARM_NONE, *)
+//  - https://reviews.llvm.org/D61973 (Support .reloc *, R_AARCH64_NONE, *)
+//  - https://reviews.llvm.org/D62052 (lld -r: fix R_*_NONE to section symbols on Elf*_Rel targets)
+#if __ANDROID_API__ >= __ANDROID_API_Q__
+#if defined(__arm__)
+asm("  .section .tdata,\"awT\",%progbits\n"
+    "  .p2align 5\n"
+    "__tls_align:\n"
+    "  .text\n"
+    "  .type __tls_align_reference,%function\n"
+    "__tls_align_reference:\n"
+    "  .long __tls_align(TPOFF)\n"
+    "  .size __tls_align_reference, .-__tls_align_reference\n");
+#elif defined(__aarch64__)
+asm("  .section .tdata,\"awT\",@progbits\n"
+    "  .p2align 6\n"
+    "__tls_align:\n"
+    "  .text\n"
+    "  .type __tls_align_reference,%function\n"
+    "__tls_align_reference:\n"
+    "  add x0, x0, :tprel_lo12_nc:__tls_align\n"
+    "  .size __tls_align_reference, .-__tls_align_reference\n");
+#endif
+#endif
+
 #include "__dso_handle.h"
 #include "atexit.h"
 #include "pthread_atfork.h"