diff --git a/libc/Android.bp b/libc/Android.bp
index b5ff680..18f1ad7 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -223,12 +223,6 @@
         "bionic/getauxval.cpp",
     ],
     arch: {
-        arm64: {
-            srcs: ["arch-arm64/bionic/__set_tls.c"],
-        },
-        riscv64: {
-            srcs: ["arch-riscv64/bionic/__set_tls.c"],
-        },
         x86: {
             srcs: [
                 "arch-x86/bionic/__libc_init_sysinfo.cpp",
@@ -236,9 +230,6 @@
                 "arch-x86/bionic/__set_tls.cpp",
             ],
         },
-        x86_64: {
-            srcs: ["arch-x86_64/bionic/__set_tls.c"],
-        },
     },
 
     defaults: ["libc_defaults"],
diff --git a/libc/arch-arm64/bionic/__set_tls.c b/libc/arch-arm64/bionic/__set_tls.c
deleted file mode 100644
index 0d88d11..0000000
--- a/libc/arch-arm64/bionic/__set_tls.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <sys/cdefs.h>
-
-__LIBC_HIDDEN__ void __set_tls(void* tls) {
-  asm("msr tpidr_el0, %0" : : "r" (tls));
-}
diff --git a/libc/arch-riscv64/bionic/__set_tls.c b/libc/arch-riscv64/bionic/__set_tls.c
deleted file mode 100644
index 57383ab..0000000
--- a/libc/arch-riscv64/bionic/__set_tls.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2022 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <sys/cdefs.h>
-
-__LIBC_HIDDEN__ void __set_tls(void* tls) {
-  asm("mv tp, %0" : : "r"(tls));
-}
diff --git a/libc/arch-x86_64/bionic/__set_tls.c b/libc/arch-x86_64/bionic/__set_tls.c
deleted file mode 100644
index 9460a03..0000000
--- a/libc/arch-x86_64/bionic/__set_tls.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <sys/cdefs.h>
-
-// ARCH_SET_FS is not exposed via <sys/prctl.h> or <linux/prctl.h>.
-#include <asm/prctl.h>
-
-extern int arch_prctl(int, unsigned long);
-
-__LIBC_HIDDEN__ int __set_tls(void* ptr) {
-  return arch_prctl(ARCH_SET_FS, (unsigned long) ptr);
-}
diff --git a/libc/bionic/ndk_cruft.cpp b/libc/bionic/ndk_cruft.cpp
index b15a317..f90b511 100644
--- a/libc/bionic/ndk_cruft.cpp
+++ b/libc/bionic/ndk_cruft.cpp
@@ -28,6 +28,9 @@
 
 // This file perpetuates the mistakes of the past.
 
+// LP64 doesn't need to support any legacy cruft.
+#if !defined(__LP64__)
+
 #include <ctype.h>
 #include <dirent.h>
 #include <errno.h>
@@ -47,10 +50,19 @@
 
 #include "platform/bionic/macros.h"
 
-extern "C" {
+#define __futex_wake __real_futex_wake
+#define __futex_wait __real_futex_wait
+#include "private/bionic_futex.h"
+#undef __futex_wake
+#undef __futex_wait
 
-// LP64 doesn't need to support any legacy cruft.
-#if !defined(__LP64__)
+#define __get_thread __real_get_thread
+#include "pthread_internal.h"
+#undef __get_thread
+static inline void** __real_get_tls() { return __get_tls(); }
+#undef __get_tls
+
+extern "C" {
 
 // By the time any NDK-built code is running, there are plenty of threads.
 int __isthreaded = 1;
@@ -73,8 +85,7 @@
 
 // TODO: does anything still need this?
 void** __get_tls() {
-#include "platform/bionic/tls.h"
-  return __get_tls();
+  return __real_get_tls();
 }
 
 // This non-standard function was in our <string.h> for some reason.
@@ -213,12 +224,6 @@
   return vdprintf(fd, fmt, ap);
 }
 
-#define __futex_wake __real_futex_wake
-#define __futex_wait __real_futex_wait
-#include "private/bionic_futex.h"
-#undef __futex_wake
-#undef __futex_wait
-
 // This used to be in <sys/atomics.h>.
 int __futex_wake(volatile void* ftx, int count) {
   return __real_futex_wake(ftx, count);
@@ -356,14 +361,6 @@
   return malloc(size);
 }
 
-} // extern "C"
-
-#define __get_thread __real_get_thread
-#include "pthread_internal.h"
-#undef __get_thread
-
-extern "C" {
-
 // Various third-party apps contain a backport of our pthread_rwlock implementation that uses this.
 pthread_internal_t* __get_thread() {
   return __real_get_thread();
@@ -388,6 +385,6 @@
     return fwrite(&value, sizeof(value), 1, fp) == 1 ? 0 : EOF;
 }
 
-#endif // !defined (__LP64__)
-
 } // extern "C"
+
+#endif // !defined (__LP64__)
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index cbaa9a6..ae9a791 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -240,8 +240,6 @@
   tcb->tls_slot(TLS_SLOT_DTV) = &val->generation;
 }
 
-extern "C" __LIBC_HIDDEN__ int __set_tls(void* ptr);
-
 __LIBC_HIDDEN__ void pthread_key_clean_all(void);
 
 // Address space is precious on LP32, so use the minimum unit: one page.
diff --git a/libc/platform/bionic/tls.h b/libc/platform/bionic/tls.h
index e01eccd..9a79f84 100644
--- a/libc/platform/bionic/tls.h
+++ b/libc/platform/bionic/tls.h
@@ -28,16 +28,60 @@
 
 #pragma once
 
+#include <sys/cdefs.h>
+
+// TODO: move the __get_tls() macros to functions instead.
+
 #if defined(__aarch64__)
+
 # define __get_tls() ({ void** __val; __asm__("mrs %0, tpidr_el0" : "=r"(__val)); __val; })
+
+static inline void __set_tls(void* tls) {
+  __asm__("msr tpidr_el0, %0" : : "r" (tls));
+}
+
 #elif defined(__arm__)
+
 # define __get_tls() ({ void** __val; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__val)); __val; })
+
+// arm32 requires a syscall.
+// By historical accident it's public API, but not in any header except this one.
+__BEGIN_DECLS
+int __set_tls(void* tls);
+__END_DECLS
+
 #elif defined(__i386__)
+
 # define __get_tls() ({ void** __val; __asm__("movl %%gs:0, %0" : "=r"(__val)); __val; })
+
+// x86 is really hairy, so we keep that out of line.
+__BEGIN_DECLS
+int __set_tls(void* tls);
+__END_DECLS
+
 #elif defined(__riscv)
+
 # define __get_tls() ({ void** __val; __asm__("mv %0, tp" : "=r"(__val)); __val; })
+
+static inline void __set_tls(void* tls) {
+  __asm__("mv tp, %0" : : "r"(tls));
+}
+
 #elif defined(__x86_64__)
+
 # define __get_tls() ({ void** __val; __asm__("mov %%fs:0, %0" : "=r"(__val)); __val; })
+
+// ARCH_SET_FS is not exposed via <sys/prctl.h> or <linux/prctl.h>.
+#include <asm/prctl.h>
+// This syscall stub is generated but it's not declared in any header.
+__BEGIN_DECLS
+int arch_prctl(int, unsigned long);
+__END_DECLS
+
+static inline int __set_tls(void* tls) {
+  return arch_prctl(ARCH_SET_FS, reinterpret_cast<unsigned long>(tls));
+}
+
 #else
 #error unsupported architecture
 #endif