diff --git a/headers/os/support/TLS.h b/headers/os/support/TLS.h
index 87c1f9b4e8..0a1b55215f 100644
--- a/headers/os/support/TLS.h
+++ b/headers/os/support/TLS.h
@@ -1,12 +1,11 @@
 /*
- * Copyright 2003-2007 Haiku, Inc. All rights reserved.
+ * Copyright 2003-2021, Haiku, Inc. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _TLS_H
 #define _TLS_H
 
 
-#include <BeBuild.h>
 #include <SupportDefs.h>
 
 
@@ -22,46 +21,10 @@ extern "C" {
 #endif	/* __cplusplus */
 
 extern int32 tls_allocate(void);
-
-#if !_NO_INLINE_ASM && __i386__ && __GNUC__
-
-static inline void *
-tls_get(int32 index)
-{
-	void *ret;
-	__asm__ __volatile__ ( 
-		"movl	%%fs:(, %1, 4), %0"
-		: "=r" (ret) : "r" (index));
-	return ret;
-}
-
-static inline void **
-tls_address(int32 index)
-{
-	void **ret;
-	__asm__ __volatile__ ( 
-		"movl	%%fs:0, %0\n\t"
-		"leal	(%0, %1, 4), %0\n\t"
-		: "=&r" (ret) : "r" (index));
-	return ret;
-}
-
-static inline void
-tls_set(int32 index, void *value)
-{
-	__asm__ __volatile__ ( 
-		"movl	%1, %%fs:(, %0, 4)"
-		: : "r" (index), "r" (value));
-}
-
-#else	/* !_NO_INLINE_ASM && __i386__ && __GNUC__ */
-
 extern void *tls_get(int32 index);
 extern void **tls_address(int32 index);
 extern void tls_set(int32 index, void *value);
 
-#endif	/* !_NO_INLINE_ASM && __i386__ && __GNUC__ */
-
 #ifdef __cplusplus
 }
 #endif	/* __cplusplus */
diff --git a/src/system/libroot/os/arch/arm/tls.c b/src/system/libroot/os/arch/arm/tls.c
index 1286a28b61..c14ee33113 100644
--- a/src/system/libroot/os/arch/arm/tls.c
+++ b/src/system/libroot/os/arch/arm/tls.c
@@ -1,15 +1,9 @@
 /*
  * Copyright 2019-2022, Haiku, Inc. All Rights Reserved.
- * Distributed under the terms of the MIT License.
- *
  * Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include <runtime_loader/runtime_loader.h>
 
 #include <support/TLS.h>
@@ -71,4 +65,3 @@ __tls_get_addr(struct tls_index *ti)
 {
 	return __gRuntimeLoader->get_tls_address(ti->ti_module, ti->ti_offset);
 }
-
diff --git a/src/system/libroot/os/arch/m68k/tls.c b/src/system/libroot/os/arch/m68k/tls.c
index dbc2eecee5..de625b00f5 100644
--- a/src/system/libroot/os/arch/m68k/tls.c
+++ b/src/system/libroot/os/arch/m68k/tls.c
@@ -1,4 +1,4 @@
-/* 
+/*
 ** Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 ** Distributed under the terms of the MIT License.
 */
@@ -9,11 +9,6 @@
 
 #warning FIXME: M68K
 
-// we don't want to have the inline assembly included here
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include <runtime_loader/runtime_loader.h>
 
 #include "support/TLS.h"
diff --git a/src/system/libroot/os/arch/ppc/tls.c b/src/system/libroot/os/arch/ppc/tls.c
index 79c0a5a632..adf1d77e51 100644
--- a/src/system/libroot/os/arch/ppc/tls.c
+++ b/src/system/libroot/os/arch/ppc/tls.c
@@ -1,4 +1,4 @@
-/* 
+/*
 ** Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 ** Distributed under the terms of the MIT License.
 */
@@ -7,11 +7,6 @@
 //	to decide how this should be done, so it's just broken now (okay for single
 //	threaded apps, though).
 
-// we don't want to have the inline assembly included here
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include "support/TLS.h"
 #include "tls.h"
 
diff --git a/src/system/libroot/os/arch/sparc/tls.c b/src/system/libroot/os/arch/sparc/tls.c
index 79c0a5a632..adf1d77e51 100644
--- a/src/system/libroot/os/arch/sparc/tls.c
+++ b/src/system/libroot/os/arch/sparc/tls.c
@@ -1,4 +1,4 @@
-/* 
+/*
 ** Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 ** Distributed under the terms of the MIT License.
 */
@@ -7,11 +7,6 @@
 //	to decide how this should be done, so it's just broken now (okay for single
 //	threaded apps, though).
 
-// we don't want to have the inline assembly included here
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include "support/TLS.h"
 #include "tls.h"
 
diff --git a/src/system/libroot/os/arch/x86/tls.c b/src/system/libroot/os/arch/x86/tls.c
index cdf94da3d7..4b4d13014e 100644
--- a/src/system/libroot/os/arch/x86/tls.c
+++ b/src/system/libroot/os/arch/x86/tls.c
@@ -5,11 +5,6 @@
  */
 
 
-// we don't want to have the inline assembly included here
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include <runtime_loader/runtime_loader.h>
 
 #include "support/TLS.h"
diff --git a/src/system/libroot/os/arch/x86_64/tls.cpp b/src/system/libroot/os/arch/x86_64/tls.cpp
index 48be9078fc..45a5489785 100644
--- a/src/system/libroot/os/arch/x86_64/tls.cpp
+++ b/src/system/libroot/os/arch/x86_64/tls.cpp
@@ -5,10 +5,6 @@
  */
 
 
-#ifndef _NO_INLINE_ASM
-#	define _NO_INLINE_ASM 1
-#endif
-
 #include <atomic>
 
 #include <runtime_loader/runtime_loader.h>