hurd: Replace threadvars with TLS

This gets rid of a lot of kludge and gets closer to other ports.

	* hurd/Makefile (headers): Remove threadvar.h.
	(inline-headers): Remove threadvar.h.
	* hurd/Versions (GLIBC_2.0: Remove __hurd_sigthread_stack_base,
	__hurd_sigthread_stack_end, __hurd_sigthread_variables,
	__hurd_threadvar_max, __hurd_errno_location.
	(HURD_CTHREADS_0.3): Add pthread_getattr_np, pthread_attr_getstack.
	* hurd/hurd/signal.h: Do not include <hurd/threadvar.h>.
	(_hurd_self_sigstate): Use THREAD_SELF to get _hurd_sigstate.
	(_HURD_SIGNAL_H_EXTERN_INLINE): Use THREAD_SELF to get _hurd_sigstate,
	unless TLS is not initialized yet, in which case we do not need a
	critical section yet anyway.
	* hurd/hurd/threadvar.h: Include <tls.h>, do not include
	<machine-sp.h>.
	(__hurd_sigthread_variables, __hurd_threadvar_max): Remove variables
	declarations.
	(__hurd_threadvar_index): Remove enum.
	(_HURD_THREADVAR_H_EXTERN_INLINE): Remove macro.
	(__hurd_threadvar_location_from_sp,__hurd_threadvar_location): Remove
	inlines.
	(__hurd_reply_port0): New variable declaration.
	(__hurd_local_reply_port): New macro.
	* hurd/hurdsig.c (__hurd_sigthread_variables): Remove variable.
	(interrupted_reply_port_location): Add thread_t parameter.  Use it
	with THREAD_TCB to access thread-local variables.
	(_hurdsig_abort_rpcs): Pass ss->thread to
	interrupted_reply_port_location.
	(_hurd_internal_post_signal): Likewise.
	(_hurdsig_init): Use presence of cthread_fork instead of
	__hurd_threadvar_stack_mask to start signal thread by hand.
	Remove signal thread threadvar initialization.
	* hurd/hurdstartup.c: Do not include <hurd/threadvar.h>
	* hurd/sigunwind.c: Include <hurd/threadvar.h>
	(_hurdsig_longjmp_from_handler): Use __hurd_local_reply_port instead
	of threadvar.
	* sysdeps/mach/hurd/Versions (libc.GLIBC_PRIVATE): Add
	__libc_lock_self0.
	(ld.GLIBC_2.0): Remove __hurd_sigthread_stack_base,
	__hurd_sigthread_stack_end, __hurd_sigthread_variables.
	(ld.GLIBC_PRIVATE): Add __libc_lock_self0.
	* sysdeps/mach/hurd/cthreads.c: Add __libc_lock_self0.
	* sysdeps/mach/hurd/dl-sysdep.c (errno, __hurd_sigthread_stack_base,
	__hurd_sigthread_stack_end, __hurd_sigthread_variables, threadvars,
	__hurd_threadvar_stack_offset, __hurd_threadvar_stack_mask): Do not
	define variables.
	* sysdeps/mach/hurd/errno-loc.c: Do not include <errno.h> and
	<hurd/threadvar.h>.
	[IS_IN(rtld)] (rtld_errno): New variable.
	[IS_IN(rtld)] (__errno_location): New weak function.
	[!IS_IN(rtld)]: Include "../../../csu/errno-loc.c".
	* sysdeps/mach/hurd/errno.c: Remove file.
	* sysdeps/mach/hurd/fork.c: Include <hurd/threadvar.h>
	(__fork): Remove THREADVAR_SPACE macro and its use.
	* sysdeps/mach/hurd/i386/init-first.c (__hurd_threadvar_max): Remove
	variable.
	(init): Do not initialize threadvar.
	* sysdeps/mach/hurd/i386/libc.abilist (__hurd_threadvar_max): Remove
	symbol.
	* sysdeps/mach/hurd/i386/sigreturn.c (__sigreturn): Use
	__hurd_local_reply_port instead of threadvar.
	* sysdeps/mach/hurd/i386/tls.h (tcbhead_t): Add reply_port and
	_hurd_sigstate fields.
	(HURD_DESC_TLS, __LIBC_NO_TLS, THREAD_TCB): New macro.
	* sysdeps/mach/hurd/i386/trampoline.c: Remove outdated comment.
	* sysdeps/mach/hurd/libc-lock.h: Do not include <hurd/threadvar.h>.
	(__libc_lock_owner_self): Use &__libc_lock_self0 and THREAD_SELF
	instead of threadvar.
	* sysdeps/mach/hurd/libc-tsd.h: Remove file.
	* sysdeps/mach/hurd/mig-reply.c (GETPORT, reply_port): Remove macros.
	(use_threadvar, global_reply_port): Remove variables.
	(__hurd_reply_port0): New variable.
	(__mig_get_reply_port): Use __hurd_local_reply_port and
	__hurd_reply_port0 instead of threadvar.
	(__mig_dealloc_reply_port): Likewise.
	(__mig_init): Do not initialize threadvar.
	* sysdeps/mach/hurd/profil.c: Fix comment.

23 files changed, 188 insertions, 263 deletions

diff --git a/ChangeLog b/ChangeLog
index 7f4721b06e..f8823b3010 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,81 @@
 	* hurd/hurdsig.c: Include <pthread.h>.
 	(_hurdsig_init): Call pthread_getattr_np and pthread_attr_getstack to
 	get the signal thread stack layout.
+	* hurd/Makefile (headers): Remove threadvar.h.
+	(inline-headers): Remove threadvar.h.
+	* hurd/Versions (GLIBC_2.0: Remove __hurd_sigthread_stack_base,
+	__hurd_sigthread_stack_end, __hurd_sigthread_variables,
+	__hurd_threadvar_max, __hurd_errno_location.
+	(HURD_CTHREADS_0.3): Add pthread_getattr_np, pthread_attr_getstack.
+	* hurd/hurd/signal.h: Do not include <hurd/threadvar.h>.
+	(_hurd_self_sigstate): Use THREAD_SELF to get _hurd_sigstate.
+	(_HURD_SIGNAL_H_EXTERN_INLINE): Use THREAD_SELF to get _hurd_sigstate,
+	unless TLS is not initialized yet, in which case we do not need a
+	critical section yet anyway.
+	* hurd/hurd/threadvar.h: Include <tls.h>, do not include
+	<machine-sp.h>.
+	(__hurd_sigthread_variables, __hurd_threadvar_max): Remove variables
+	declarations.
+	(__hurd_threadvar_index): Remove enum.
+	(_HURD_THREADVAR_H_EXTERN_INLINE): Remove macro.
+	(__hurd_threadvar_location_from_sp,__hurd_threadvar_location): Remove
+	inlines.
+	(__hurd_reply_port0): New variable declaration.
+	(__hurd_local_reply_port): New macro.
+	* hurd/hurdsig.c (__hurd_sigthread_variables): Remove variable.
+	(interrupted_reply_port_location): Add thread_t parameter.  Use it
+	with THREAD_TCB to access thread-local variables.
+	(_hurdsig_abort_rpcs): Pass ss->thread to
+	interrupted_reply_port_location.
+	(_hurd_internal_post_signal): Likewise.
+	(_hurdsig_init): Use presence of cthread_fork instead of
+	__hurd_threadvar_stack_mask to start signal thread by hand.
+	Remove signal thread threadvar initialization.
+	* hurd/hurdstartup.c: Do not include <hurd/threadvar.h>
+	* hurd/sigunwind.c: Include <hurd/threadvar.h>
+	(_hurdsig_longjmp_from_handler): Use __hurd_local_reply_port instead
+	of threadvar.
+	* sysdeps/mach/hurd/Versions (libc.GLIBC_PRIVATE): Add
+	__libc_lock_self0.
+	(ld.GLIBC_2.0): Remove __hurd_sigthread_stack_base,
+	__hurd_sigthread_stack_end, __hurd_sigthread_variables.
+	(ld.GLIBC_PRIVATE): Add __libc_lock_self0.
+	* sysdeps/mach/hurd/cthreads.c: Add __libc_lock_self0.
+	* sysdeps/mach/hurd/dl-sysdep.c (errno, __hurd_sigthread_stack_base,
+	__hurd_sigthread_stack_end, __hurd_sigthread_variables, threadvars,
+	__hurd_threadvar_stack_offset, __hurd_threadvar_stack_mask): Do not
+	define variables.
+	* sysdeps/mach/hurd/errno-loc.c: Do not include <errno.h> and
+	<hurd/threadvar.h>.
+	[IS_IN(rtld)] (rtld_errno): New variable.
+	[IS_IN(rtld)] (__errno_location): New weak function.
+	[!IS_IN(rtld)]: Include "../../../csu/errno-loc.c".
+	* sysdeps/mach/hurd/errno.c: Remove file.
+	* sysdeps/mach/hurd/fork.c: Include <hurd/threadvar.h>
+	(__fork): Remove THREADVAR_SPACE macro and its use.
+	* sysdeps/mach/hurd/i386/init-first.c (__hurd_threadvar_max): Remove
+	variable.
+	(init): Do not initialize threadvar.
+	* sysdeps/mach/hurd/i386/libc.abilist (__hurd_threadvar_max): Remove
+	symbol.
+	* sysdeps/mach/hurd/i386/sigreturn.c (__sigreturn): Use
+	__hurd_local_reply_port instead of threadvar.
+	* sysdeps/mach/hurd/i386/tls.h (tcbhead_t): Add reply_port and
+	_hurd_sigstate fields.
+	(HURD_DESC_TLS, __LIBC_NO_TLS, THREAD_TCB): New macro.
+	* sysdeps/mach/hurd/i386/trampoline.c: Remove outdated comment.
+	* sysdeps/mach/hurd/libc-lock.h: Do not include <hurd/threadvar.h>.
+	(__libc_lock_owner_self): Use &__libc_lock_self0 and THREAD_SELF
+	instead of threadvar.
+	* sysdeps/mach/hurd/libc-tsd.h: Remove file.
+	* sysdeps/mach/hurd/mig-reply.c (GETPORT, reply_port): Remove macros.
+	(use_threadvar, global_reply_port): Remove variables.
+	(__hurd_reply_port0): New variable.
+	(__mig_get_reply_port): Use __hurd_local_reply_port and
+	__hurd_reply_port0 instead of threadvar.
+	(__mig_dealloc_reply_port): Likewise.
+	(__mig_init): Do not initialize threadvar.
+	* sysdeps/mach/hurd/profil.c: Fix comment.
 
 2018-03-16  Samuel Thibault  <samuel.thibault@ens-lyon.org>
 
diff --git a/hurd/Makefile b/hurd/Makefile
index cca08a175a..2b318c9ca0 100644
--- a/hurd/Makefile
+++ b/hurd/Makefile
@@ -21,10 +21,10 @@ include ../Makeconfig
 
 headers = hurd.h $(interface-headers) \
 	  $(addprefix hurd/,fd.h id.h port.h signal.h sigpreempt.h ioctl.h\
-			    userlink.h resource.h threadvar.h lookup.h)
+			    userlink.h resource.h lookup.h)
 
 inline-headers = hurd.h $(addprefix hurd/,fd.h signal.h \
-					  userlink.h threadvar.h port.h)
+					  userlink.h port.h)
 
 # The RPC interfaces go in a separate library.
 interface-library := libhurduser
diff --git a/hurd/Versions b/hurd/Versions
index b1253e653e..164aa64400 100644
--- a/hurd/Versions
+++ b/hurd/Versions
@@ -4,14 +4,8 @@ libc {
     _end;
 
     # variables used in macros & inline functions
-    __hurd_sigthread_stack_base; __hurd_sigthread_stack_end;
-    __hurd_sigthread_variables;
-    __hurd_threadvar_max;
     __hurd_threadvar_stack_mask; __hurd_threadvar_stack_offset;
 
-    # functions used in macros & inline functions
-    __hurd_errno_location;
-
     # functions used in libmachuser and libhurduser
     _S_catch_exception_raise;
     _S_catch_exception_raise_state;
@@ -146,6 +140,7 @@ libc {
   HURD_CTHREADS_0.3 {
     # weak refs to libthreads functions that libc calls iff libthreads in use
     cthread_fork; cthread_detach;
+    pthread_getattr_np; pthread_attr_getstack;
 
     # variables used for detecting cthreads
     _cthread_exit_routine; _cthread_init_routine;
diff --git a/hurd/hurd/signal.h b/hurd/hurd/signal.h
index 0e3315a6fe..eb9b0ca423 100644
--- a/hurd/hurd/signal.h
+++ b/hurd/hurd/signal.h
@@ -40,7 +40,6 @@
 #include <cthreads.h>		/* For `struct mutex'.  */
 #include <setjmp.h>		/* For `jmp_buf'.  */
 #include <spin-lock.h>
-#include <hurd/threadvar.h>	/* We cache sigstate in a threadvar.  */
 struct hurd_signal_preemptor;	/* <hurd/sigpreempt.h> */
 #if defined __USE_EXTERN_INLINES && defined _LIBC
 # if IS_IN (libc) || IS_IN (libpthread)
@@ -139,11 +138,9 @@ extern struct hurd_sigstate *_hurd_self_sigstate (void)
 _HURD_SIGNAL_H_EXTERN_INLINE struct hurd_sigstate *
 _hurd_self_sigstate (void)
 {
-  struct hurd_sigstate **location = (struct hurd_sigstate **)
-    (void *) __hurd_threadvar_location (_HURD_THREADVAR_SIGSTATE);
-  if (*location == NULL)
-    *location = _hurd_thread_sigstate (__mach_thread_self ());
-  return *location;
+  if (THREAD_SELF->_hurd_sigstate == NULL)
+    THREAD_SELF->_hurd_sigstate = _hurd_thread_sigstate (__mach_thread_self ());
+  return THREAD_SELF->_hurd_sigstate;
 }
 # endif
 #endif
@@ -180,16 +177,22 @@ extern void *_hurd_critical_section_lock (void);
 _HURD_SIGNAL_H_EXTERN_INLINE void *
 _hurd_critical_section_lock (void)
 {
-  struct hurd_sigstate **location = (struct hurd_sigstate **)
-    (void *) __hurd_threadvar_location (_HURD_THREADVAR_SIGSTATE);
-  struct hurd_sigstate *ss = *location;
+  struct hurd_sigstate *ss;
+
+#ifdef __LIBC_NO_TLS
+  if (__LIBC_NO_TLS())
+    /* TLS is currently initializing, no need to enter critical section.  */
+    return NULL;
+#endif
+
+  ss = THREAD_SELF->_hurd_sigstate;
   if (ss == NULL)
     {
       /* The thread variable is unset; this must be the first time we've
 	 asked for it.  In this case, the critical section flag cannot
 	 possible already be set.  Look up our sigstate structure the slow
 	 way.  */
-      ss = *location = _hurd_thread_sigstate (__mach_thread_self ());
+      ss = THREAD_SELF->_hurd_sigstate = _hurd_thread_sigstate (__mach_thread_self ());
     }
 
   if (! __spin_try_lock (&ss->critical_section_lock))
diff --git a/hurd/hurd/threadvar.h b/hurd/hurd/threadvar.h
index 9b9b863dd6..89918e34c3 100644
--- a/hurd/hurd/threadvar.h
+++ b/hurd/hurd/threadvar.h
@@ -20,6 +20,7 @@
 #define	_HURD_THREADVAR_H
 
 #include <features.h>
+#include <tls.h>
 
 /* The per-thread variables are found by ANDing this mask
    with the value of the stack pointer and then adding this offset.
@@ -30,96 +31,24 @@
    __hurd_threadvar_stack_offset to a small offset that skips the data
    cthreads itself maintains at the base of each thread's stack.
 
-   In the single-threaded case, __hurd_threadvar_stack_mask is zero, so the
-   stack pointer is ignored; and __hurd_threadvar_stack_offset gives the
-   address of a small allocated region which contains the variables for the
-   single thread.  */
+   In the single-threaded or libpthread case, __hurd_threadvar_stack_mask is
+   zero, so the stack pointer is ignored. */
 
 extern unsigned long int __hurd_threadvar_stack_mask;
 extern unsigned long int __hurd_threadvar_stack_offset;
 
-/* A special case must always be made for the signal thread.  Even when there
-   is only one user thread and an allocated region can be used for the user
-   thread's variables, the signal thread needs to have its own location for
-   per-thread variables.  The variables __hurd_sigthread_stack_base and
+/* The variables __hurd_sigthread_stack_base and
    __hurd_sigthread_stack_end define the bounds of the stack used by the
    signal thread, so that thread can always be specifically identified.  */
 
 extern unsigned long int __hurd_sigthread_stack_base;
 extern unsigned long int __hurd_sigthread_stack_end;
-extern unsigned long int *__hurd_sigthread_variables;
 
+/* Store the MiG reply port reply port until we enable TLS.  */
+extern mach_port_t __hurd_reply_port0;
 
-/* At the location described by the two variables above,
-   there are __hurd_threadvar_max `unsigned long int's of per-thread data.  */
-extern unsigned int __hurd_threadvar_max;
-
-/* These values are the indices for the standard per-thread variables.  */
-enum __hurd_threadvar_index
-  {
-    _HURD_THREADVAR_MIG_REPLY,	/* Reply port for MiG user stub functions.  */
-    _HURD_THREADVAR_ERRNO,	/* `errno' value for this thread.  */
-    _HURD_THREADVAR_SIGSTATE,	/* This thread's `struct hurd_sigstate'.  */
-    _HURD_THREADVAR_DYNAMIC_USER, /* Dynamically-assigned user variables.  */
-    _HURD_THREADVAR_MALLOC,	/* For use of malloc.  */
-    _HURD_THREADVAR_DL_ERROR,	/* For use of -ldl and dynamic linker.  */
-    _HURD_THREADVAR_RPC_VARS,	/* For state of RPC functions.  */
-    _HURD_THREADVAR_LOCALE,	/* For thread-local locale setting.  */
-    _HURD_THREADVAR_CTYPE_B,	/* Cache of thread-local locale data.  */
-    _HURD_THREADVAR_CTYPE_TOLOWER, /* Cache of thread-local locale data.  */
-    _HURD_THREADVAR_CTYPE_TOUPPER, /* Cache of thread-local locale data.  */
-    _HURD_THREADVAR_MAX		/* Default value for __hurd_threadvar_max.  */
-  };
-
-
-#ifndef _HURD_THREADVAR_H_EXTERN_INLINE
-#define _HURD_THREADVAR_H_EXTERN_INLINE __extern_inline
-#endif
-
-/* Return the location of the value for the per-thread variable with index
-   INDEX used by the thread whose stack pointer is SP.  */
-
-extern unsigned long int *__hurd_threadvar_location_from_sp
-  (enum __hurd_threadvar_index __index, void *__sp);
-
-#if defined __USE_EXTERN_INLINES && defined _LIBC
-# if IS_IN (libc)
-_HURD_THREADVAR_H_EXTERN_INLINE unsigned long int *
-__hurd_threadvar_location_from_sp (enum __hurd_threadvar_index __index,
-				   void *__sp)
-{
-  unsigned long int __stack = (unsigned long int) __sp;
-  return &((__stack >= __hurd_sigthread_stack_base &&
-	    __stack < __hurd_sigthread_stack_end)
-	   ? __hurd_sigthread_variables
-	   : (unsigned long int *) ((__stack & __hurd_threadvar_stack_mask) +
-				    __hurd_threadvar_stack_offset))[__index];
-}
-# endif
-#endif
-
-#include <machine-sp.h>		/* Define __thread_stack_pointer.  */
-
-/* Return the location of the current thread's value for the
-   per-thread variable with index INDEX.  */
-
-extern unsigned long int *
-__hurd_threadvar_location (enum __hurd_threadvar_index __index) __THROW
-     /* This declaration tells the compiler that the value is constant
-	given the same argument.  We assume this won't be called twice from
-	the same stack frame by different threads.  */
-     __attribute__ ((__const__));
-
-#if defined __USE_EXTERN_INLINES && defined _LIBC
-# if IS_IN (libc)
-_HURD_THREADVAR_H_EXTERN_INLINE unsigned long int *
-__hurd_threadvar_location (enum __hurd_threadvar_index __index)
-{
-  return __hurd_threadvar_location_from_sp (__index,
-					    __thread_stack_pointer ());
-}
-# endif
-#endif
-
+/* This returns either the TLS reply port variable, or a single-thread variable
+   when TLS is not initialized yet.  */
+#define __hurd_local_reply_port (*(__LIBC_NO_TLS() ? &__hurd_reply_port0 : &THREAD_SELF->reply_port))
 
 #endif	/* hurd/threadvar.h */
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index 198546fbb3..8069de391f 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -49,7 +49,6 @@ thread_t _hurd_sigthread;
 /* These are set up by _hurdsig_init.  */
 unsigned long int __hurd_sigthread_stack_base;
 unsigned long int __hurd_sigthread_stack_end;
-unsigned long int *__hurd_sigthread_variables;
 
 /* Linked-list of per-thread signal state.  */
 struct hurd_sigstate *_hurd_sigstates;
@@ -235,14 +234,14 @@ abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state,
    that this location can be set without faulting, or else return NULL.  */
 
 static mach_port_t *
-interrupted_reply_port_location (struct machine_thread_all_state *thread_state,
+interrupted_reply_port_location (thread_t thread,
+				 struct machine_thread_all_state *thread_state,
 				 int sigthread)
 {
-  mach_port_t *portloc = (mach_port_t *) __hurd_threadvar_location_from_sp
-    (_HURD_THREADVAR_MIG_REPLY, (void *) thread_state->basic.SP);
+  mach_port_t *portloc = &THREAD_TCB(thread, thread_state)->reply_port;
 
   if (sigthread && _hurdsig_catch_memory_fault (portloc))
-    /* Faulted trying to read the stack.  */
+    /* Faulted trying to read the TCB.  */
     return NULL;
 
   /* Fault now if this pointer is bogus.  */
@@ -324,7 +323,8 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
 	   our nonzero return tells the trampoline code to finish the message
 	   receive operation before running the handler.  */
 
-	mach_port_t *reply = interrupted_reply_port_location (state,
+	mach_port_t *reply = interrupted_reply_port_location (ss->thread,
+							      state,
 							      sigthread);
 	error_t err = __interrupt_operation (intr_port, _hurdsig_interrupt_timeout);
 
@@ -836,7 +836,8 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss,
 
 	    if (! machine_get_basic_state (ss->thread, &thread_state))
 	      goto sigbomb;
-	    loc = interrupted_reply_port_location (&thread_state, 1);
+	    loc = interrupted_reply_port_location (ss->thread,
+						   &thread_state, 1);
 	    if (loc && *loc != MACH_PORT_NULL)
 	      /* This is the reply port for the context which called
 		 sigreturn.  Since we are abandoning that context entirely
@@ -902,7 +903,8 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss,
 	{
 	  /* Fetch the thread variable for the MiG reply port,
 	     and set it to MACH_PORT_NULL.  */
-	  mach_port_t *loc = interrupted_reply_port_location (&thread_state,
+	  mach_port_t *loc = interrupted_reply_port_location (ss->thread,
+							      &thread_state,
 							      1);
 	  if (loc)
 	    {
@@ -1256,7 +1258,8 @@ _hurdsig_init (const int *intarray, size_t intarraysize)
 
   /* Start the signal thread listening on the message port.  */
 
-  if (__hurd_threadvar_stack_mask == 0)
+#pragma weak cthread_fork
+  if (!cthread_fork)
     {
       err = __thread_create (__mach_task_self (), &_hurd_msgport_thread);
       assert_perror (err);
@@ -1269,14 +1272,6 @@ _hurdsig_init (const int *intarray, size_t intarraysize)
       assert_perror (err);
 
       __hurd_sigthread_stack_end = __hurd_sigthread_stack_base + stacksize;
-      __hurd_sigthread_variables =
-	malloc (__hurd_threadvar_max * sizeof (unsigned long int));
-      if (__hurd_sigthread_variables == NULL)
-	__libc_fatal ("hurd: Can't allocate threadvars for signal thread\n");
-      memset (__hurd_sigthread_variables, 0,
-	      __hurd_threadvar_max * sizeof (unsigned long int));
-      __hurd_sigthread_variables[_HURD_THREADVAR_LOCALE]
-	= (unsigned long int) &_nl_global_locale;
 
       /* Reinitialize the MiG support routines so they will use a per-thread
 	 variable for the cached reply port.  */
@@ -1296,7 +1291,6 @@ _hurdsig_init (const int *intarray, size_t intarraysize)
          we'll let the signal thread's per-thread variables be found as for
          any normal cthread, and just leave the magic __hurd_sigthread_*
          values all zero so they'll be ignored.  */
-#pragma weak cthread_fork
 #pragma weak cthread_detach
 #pragma weak pthread_getattr_np
 #pragma weak pthread_attr_getstack
diff --git a/hurd/hurdstartup.c b/hurd/hurdstartup.c
index bd9eca27b7..b148125c96 100644
--- a/hurd/hurdstartup.c
+++ b/hurd/hurdstartup.c
@@ -23,7 +23,6 @@
 #include <hurd.h>
 #include <hurd/exec_startup.h>
 #include <sysdep.h>
-#include <hurd/threadvar.h>
 #include <unistd.h>
 #include <elf.h>
 #include <set-hooks.h>
diff --git a/hurd/sigunwind.c b/hurd/sigunwind.c
index 4db9827d44..40e0f679f7 100644
--- a/hurd/sigunwind.c
+++ b/hurd/sigunwind.c
@@ -18,6 +18,7 @@
 
 #include <hurd.h>
 #include <thread_state.h>
+#include <hurd/threadvar.h>
 #include <jmpbuf-unwind.h>
 #include <assert.h>
 #include <stdint.h>
@@ -38,8 +39,7 @@ _hurdsig_longjmp_from_handler (void *data, jmp_buf env, int val)
     {
       /* Destroy the MiG reply port used by the signal handler, and restore
 	 the reply port in use by the thread when interrupted.  */
-      mach_port_t *reply_port =
-	(mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY);
+      mach_port_t *reply_port = &__hurd_local_reply_port;
       if (*reply_port)
 	{
 	  mach_port_t port = *reply_port;
diff --git a/sysdeps/mach/hurd/Versions b/sysdeps/mach/hurd/Versions
index 89e19061af..7cab8e8551 100644
--- a/sysdeps/mach/hurd/Versions
+++ b/sysdeps/mach/hurd/Versions
@@ -6,6 +6,7 @@ libc {
   GLIBC_PRIVATE {
     # Functions shared with the dynamic linker
     __libc_read; __libc_write; __libc_lseek64;
+    __libc_lock_self0;
 
     _dl_init_first;
   }
@@ -14,8 +15,6 @@ libc {
 ld {
   GLIBC_2.0 {
     # variables that must be shared with libc
-    __hurd_sigthread_stack_base; __hurd_sigthread_stack_end;
-    __hurd_sigthread_variables;
     __hurd_threadvar_stack_mask;  __hurd_threadvar_stack_offset;
 
     # functions that must be shared with libc
@@ -33,5 +32,6 @@ ld {
 
     # functions that must be shared with libc
     __libc_read; __libc_write; __libc_lseek64;
+    __libc_lock_self0;
   }
 }
diff --git a/sysdeps/mach/hurd/cthreads.c b/sysdeps/mach/hurd/cthreads.c
index e0cf4ddca7..640c97ec1d 100644
--- a/sysdeps/mach/hurd/cthreads.c
+++ b/sysdeps/mach/hurd/cthreads.c
@@ -19,6 +19,10 @@
 #include <errno.h>
 #include <stdlib.h>
 
+/* This serves as stub "self" pointer for libc locks when TLS is not initialized
+   yet.  */
+char __libc_lock_self0[0];
+
 /* Placeholder for key creation routine from Hurd cthreads library.  */
 int
 weak_function
diff --git a/sysdeps/mach/hurd/dl-sysdep.c b/sysdeps/mach/hurd/dl-sysdep.c
index 1317fd5328..cbf4e05862 100644
--- a/sysdeps/mach/hurd/dl-sysdep.c
+++ b/sysdeps/mach/hurd/dl-sysdep.c
@@ -70,25 +70,6 @@ void *_dl_random attribute_relro = NULL;
 
 struct hurd_startup_data *_dl_hurd_data;
 
-/* This is used only within ld.so, via dl-minimal.c's __errno_location.  */
-#undef errno
-int errno attribute_hidden;
-
-/* Defining these variables here avoids the inclusion of hurdsig.c.  */
-unsigned long int __hurd_sigthread_stack_base;
-unsigned long int __hurd_sigthread_stack_end;
-unsigned long int *__hurd_sigthread_variables;
-
-/* Defining these variables here avoids the inclusion of init-first.c.
-   We need to provide temporary storage for the per-thread variables
-   of the main user thread here, since it is used for storing the
-   `errno' variable.  Note that this information is lost once we
-   relocate the dynamic linker.  */
-static unsigned long int threadvars[_HURD_THREADVAR_MAX];
-unsigned long int __hurd_threadvar_stack_offset
-  = (unsigned long int) &threadvars;
-unsigned long int __hurd_threadvar_stack_mask;
-
 #define FMH defined(__i386__)
 #if ! FMH
 # define fmh()		((void)0)
diff --git a/sysdeps/mach/hurd/errno-loc.c b/sysdeps/mach/hurd/errno-loc.c
index 7b1e7ce347..95d0fe47c4 100644
--- a/sysdeps/mach/hurd/errno-loc.c
+++ b/sysdeps/mach/hurd/errno-loc.c
@@ -16,13 +16,21 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <hurd/threadvar.h>
-
-int *
+#if IS_IN (rtld)
+/*
+ * rtld can not access TLS too early, thus rtld_errno.
+ *
+ * Instead of making __open/__close pass errno from TLS to rtld_errno, simply
+ * use a weak __errno_location using rtld_errno, which will be overriden by the
+ * libc definition.
+ */
+static int rtld_errno;
+int * weak_function
 __errno_location (void)
 {
-  return (int *) __hurd_threadvar_location (_HURD_THREADVAR_ERRNO);
+  return &rtld_errno;
 }
-strong_alias (__errno_location, __hurd_errno_location)
-libc_hidden_def (__errno_location)
+libc_hidden_weak (__errno_location)
+#else
+#include "../../../csu/errno-loc.c"
+#endif
diff --git a/sysdeps/mach/hurd/errno.c b/sysdeps/mach/hurd/errno.c
deleted file mode 100644
index a29091b5e2..0000000000
--- a/sysdeps/mach/hurd/errno.c
+++ /dev/null
@@ -1 +0,0 @@
-/* No definition of `errno' variable on the Hurd.  */
diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index cc322ebee5..2d1e64c8d1 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -19,6 +19,7 @@
 #include <unistd.h>
 #include <hurd.h>
 #include <hurd/signal.h>
+#include <hurd/threadvar.h>
 #include <setjmp.h>
 #include <thread_state.h>
 #include <sysdep.h>		/* For stack growth direction.  */
@@ -483,19 +484,17 @@ __fork (void)
 				    (natural_t *) &state, &statecount))
 	LOSE;
 #ifdef STACK_GROWTH_UP
-#define THREADVAR_SPACE (__hurd_threadvar_max \
-			 * sizeof *__hurd_sightread_variables)
       if (__hurd_sigthread_stack_base == 0)
 	{
 	  state.SP &= __hurd_threadvar_stack_mask;
-	  state.SP += __hurd_threadvar_stack_offset + THREADVAR_SPACE;
+	  state.SP += __hurd_threadvar_stack_offset;
 	}
       else
 	state.SP = __hurd_sigthread_stack_base;
 #else
       if (__hurd_sigthread_stack_end == 0)
 	{
-	  /* The signal thread has a normal stack assigned by cthreads.
+	  /* The signal thread has a stack assigned by cthreads.
 	     The threadvar_stack variables conveniently tell us how
 	     to get to the highest address in the stack, just below
 	     the per-thread variables.  */
diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
index 965b53ca9e..f4a4df33de 100644
--- a/sysdeps/mach/hurd/i386/init-first.c
+++ b/sysdeps/mach/hurd/i386/init-first.c
@@ -35,7 +35,6 @@ extern void __mach_init (void);
 extern void __init_misc (int, char **, char **);
 extern void __libc_global_ctors (void);
 
-unsigned int __hurd_threadvar_max;
 unsigned long int __hurd_threadvar_stack_offset;
 unsigned long int __hurd_threadvar_stack_mask;
 
@@ -169,15 +168,6 @@ init (int *data)
   char **argv = (void *) (data + 1);
   char **envp = &argv[argc + 1];
   struct hurd_startup_data *d;
-  unsigned long int threadvars[_HURD_THREADVAR_MAX];
-
-  /* Provide temporary storage for thread-specific variables on the
-     startup stack so the cthreads initialization code can use them
-     for malloc et al, or so we can use malloc below for the real
-     threadvars array.  */
-  memset (threadvars, 0, sizeof threadvars);
-  threadvars[_HURD_THREADVAR_LOCALE] = (unsigned long int) &_nl_global_locale;
-  __hurd_threadvar_stack_offset = (unsigned long int) threadvars;
 
   /* Since the cthreads initialization code uses malloc, and the
      malloc initialization code needs to get at the environment, make
@@ -190,13 +180,6 @@ init (int *data)
     ++envp;
   d = (void *) ++envp;
 
-  /* The user might have defined a value for this, to get more variables.
-     Otherwise it will be zero on startup.  We must make sure it is set
-     properly before before cthreads initialization, so cthreads can know
-     how much space to leave for thread variables.  */
-  if (__hurd_threadvar_max < _HURD_THREADVAR_MAX)
-    __hurd_threadvar_max = _HURD_THREADVAR_MAX;
-
 
   /* After possibly switching stacks, call `init1' (above) with the user
      code as the return address, and the argument data immediately above
@@ -212,11 +195,6 @@ init (int *data)
 
       __libc_stack_end = newsp;
 
-      /* Copy per-thread variables from that temporary
-	 area onto the new cthread stack.  */
-      memcpy (__hurd_threadvar_location_from_sp (0, newsp),
-	      threadvars, sizeof threadvars);
-
       /* Copy the argdata from the old stack to the new one.  */
       newsp = memcpy (newsp - ((char *) &d[1] - (char *) data), data,
 		      (char *) d - (char *) data);
@@ -257,25 +235,10 @@ init (int *data)
     }
   else
     {
-      /* We are not using cthreads, so we will have just a single allocated
-	 area for the per-thread variables of the main user thread.  */
-      unsigned long int *array;
-      unsigned int i;
       int usercode;
 
       void call_init1 (void);
 
-      array = malloc (__hurd_threadvar_max * sizeof (unsigned long int));
-      if (array == NULL)
-	__libc_fatal ("Can't allocate single-threaded thread variables.");
-
-      /* Copy per-thread variables from the temporary array into the
-	 newly malloc'd space.  */
-      memcpy (array, threadvars, sizeof threadvars);
-      __hurd_threadvar_stack_offset = (unsigned long int) array;
-      for (i = _HURD_THREADVAR_MAX; i < __hurd_threadvar_max; ++i)
-	array[i] = 0;
-
       /* The argument data is just above the stack frame we will unwind by
 	 returning.  Mutate our own return address to run the code below.  */
       /* The following expression would typically be written as
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index 991c41b374..9545e898c1 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -285,7 +285,6 @@ GLIBC_2.2.6 __gettimeofday F
 GLIBC_2.2.6 __gmtime_r F
 GLIBC_2.2.6 __h_errno_location F
 GLIBC_2.2.6 __hurd_fail F
-GLIBC_2.2.6 __hurd_threadvar_max D 0x4
 GLIBC_2.2.6 __hurd_threadvar_stack_mask D 0x4
 GLIBC_2.2.6 __hurd_threadvar_stack_offset D 0x4
 GLIBC_2.2.6 __isalnum_l F
diff --git a/sysdeps/mach/hurd/i386/sigreturn.c b/sysdeps/mach/hurd/i386/sigreturn.c
index 8ec1d4b91f..07633e17c8 100644
--- a/sysdeps/mach/hurd/i386/sigreturn.c
+++ b/sysdeps/mach/hurd/i386/sigreturn.c
@@ -68,7 +68,7 @@ __sigreturn (struct sigcontext *scp)
 
   if (scp->sc_onstack)
     {
-      ss->sigaltstack.ss_flags &= ~SS_ONSTACK; /* XXX threadvars */
+      ss->sigaltstack.ss_flags &= ~SS_ONSTACK;
       /* XXX cannot unlock until off sigstack */
       abort ();
     }
@@ -77,8 +77,7 @@ __sigreturn (struct sigcontext *scp)
 
   /* Destroy the MiG reply port used by the signal handler, and restore the
      reply port in use by the thread when interrupted.  */
-  reply_port =
-    (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY);
+  reply_port = &__hurd_local_reply_port;
   if (*reply_port)
     {
       mach_port_t port = *reply_port;
diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h
index 4c78685045..6cd1730887 100644
--- a/sysdeps/mach/hurd/i386/tls.h
+++ b/sysdeps/mach/hurd/i386/tls.h
@@ -43,9 +43,27 @@ typedef struct
   void *__private_tm[4];
   /* GCC split stack support.  */
   void *__private_ss;
+
+  /* Keep this field last, so fields above can continue being compatible with
+     the Linux version. */
+  mach_port_t reply_port;      /* This thread's reply port.  */
+  struct hurd_sigstate *_hurd_sigstate;
 } tcbhead_t;
 #endif
 
+/* Return tcbhead_t from a TLS segment descriptor.  */
+# define HURD_DESC_TLS(desc)						      \
+  ({									      \
+   (tcbhead_t *) (   (desc->low_word >> 16)				      \
+                  | ((desc->high_word & 0xff) << 16)			      \
+                  |  (desc->high_word & 0xff000000));			      \
+  })
+
+/* Return 1 if TLS is not initialized yet.  */
+#define __LIBC_NO_TLS()							      \
+  ({ unsigned short ds, gs;						      \
+     asm ("movw %%ds,%w0; movw %%gs,%w1" : "=q" (ds), "=q" (gs));	      \
+     __builtin_expect(ds == gs, 0); })
 
 /* The TCB can have any size and the memory following the address the
    thread pointer points to is unspecified.  Allocate the TCB there.  */
@@ -138,6 +156,21 @@ _hurd_tls_init (tcbhead_t *tcb)
 	      : "i" (offsetof (tcbhead_t, tcb)));			      \
      __tcb;})
 
+/* Return the TCB address of a thread given its state.
+   Note: this is expensive.  */
+# define THREAD_TCB(thread, thread_state)				      \
+  ({ int __sel = (thread_state)->basic.gs;				      \
+     struct descriptor __desc, *___desc = &__desc;			      \
+     unsigned int __count = 1;						      \
+     kern_return_t __err;						      \
+     if (HURD_SEL_LDT(__sel))						      \
+       __err = __i386_get_ldt ((thread), __sel, 1, &___desc, &__count);	      \
+     else								      \
+       __err = __i386_get_gdt ((thread), __sel, &__desc);		      \
+     assert_perror (__err);						      \
+     assert (__count == 1);						      \
+     HURD_DESC_TLS(___desc);})
+
 /* Install new dtv for current thread.  */
 # define INSTALL_NEW_DTV(dtvp)						      \
   ({ asm volatile ("movl %0,%%gs:%P1"					      \
diff --git a/sysdeps/mach/hurd/i386/trampoline.c b/sysdeps/mach/hurd/i386/trampoline.c
index 0c68759f42..0e795f9389 100644
--- a/sysdeps/mach/hurd/i386/trampoline.c
+++ b/sysdeps/mach/hurd/i386/trampoline.c
@@ -79,8 +79,6 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
     {
       sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
       ss->sigaltstack.ss_flags |= SS_ONSTACK;
-      /* XXX need to set up base of new stack for
-	 per-thread variables, cthreads.  */
     }
   /* This code has intimate knowledge of the special mach_msg system call
      done in intr-msg.c; that code does (see intr-msg.h):
diff --git a/sysdeps/mach/hurd/libc-lock.h b/sysdeps/mach/hurd/libc-lock.h
index 371912efb7..2dfade93eb 100644
--- a/sysdeps/mach/hurd/libc-lock.h
+++ b/sysdeps/mach/hurd/libc-lock.h
@@ -21,7 +21,6 @@
 
 #if (_LIBC - 0) || (_CTHREADS_ - 0)
 #include <cthreads.h>
-#include <hurd/threadvar.h>
 
 /* The locking here is very inexpensive, even for inlining.  */
 #define _IO_lock_inexpensive  1
@@ -35,7 +34,8 @@ typedef struct
 } __libc_lock_recursive_t;
 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
 
-#define __libc_lock_owner_self() ((void *) __hurd_threadvar_location (0))
+extern char __libc_lock_self0[0];
+#define __libc_lock_owner_self() (__LIBC_NO_TLS() ? &__libc_lock_self0 : THREAD_SELF)
 
 #else
 typedef struct __libc_lock_opaque__ __libc_lock_t;
diff --git a/sysdeps/mach/hurd/libc-tsd.h b/sysdeps/mach/hurd/libc-tsd.h
deleted file mode 100644
index fa131a2d5a..0000000000
--- a/sysdeps/mach/hurd/libc-tsd.h
+++ /dev/null
@@ -1,34 +0,0 @@
-/* libc-internal interface for thread-specific data.  Hurd version.
-   Copyright (C) 1998-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#ifndef _LIBC_TSD_H
-#define _LIBC_TSD_H 1
-
-#include <hurd/threadvar.h>
-
-#define __libc_tsd_define(CLASS, TYPE, KEY) /* nothing, always have threadvars */
-
-#define __libc_tsd_address(TYPE, KEY) \
-  ((TYPE *) __hurd_threadvar_location (_HURD_THREADVAR_##KEY))
-
-#define __libc_tsd_get(TYPE, KEY) \
-  (*__libc_tsd_address (TYPE, KEY))
-#define __libc_tsd_set(TYPE, KEY, VALUE) \
-  (*__libc_tsd_address (TYPE, KEY) = (VALUE))
-
-#endif	/* libc-tsd.h */
diff --git a/sysdeps/mach/hurd/mig-reply.c b/sysdeps/mach/hurd/mig-reply.c
index ed3705dc41..ddad12e070 100644
--- a/sysdeps/mach/hurd/mig-reply.c
+++ b/sysdeps/mach/hurd/mig-reply.c
@@ -18,26 +18,20 @@
 #include <mach.h>
 #include <hurd/threadvar.h>
 
-#define GETPORT \
-  mach_port_t *portloc = \
-    (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY)
-#define reply_port (*(use_threadvar ? portloc : &global_reply_port))
-
-static int use_threadvar;
-static mach_port_t global_reply_port;
-
 /* These functions are called by MiG-generated code.  */
 
+mach_port_t __hurd_reply_port0;
+
 /* Called by MiG to get a reply port.  */
 mach_port_t
 __mig_get_reply_port (void)
 {
-  GETPORT;
-
-  if (reply_port == MACH_PORT_NULL)
-    reply_port = __mach_reply_port ();
+  if (__hurd_local_reply_port == MACH_PORT_NULL ||
+      (&__hurd_local_reply_port != &__hurd_reply_port0
+       && __hurd_local_reply_port == __hurd_reply_port0))
+    __hurd_local_reply_port = __mach_reply_port ();
 
-  return reply_port;
+  return __hurd_local_reply_port;
 }
 weak_alias (__mig_get_reply_port, mig_get_reply_port)
 
@@ -45,12 +39,8 @@ weak_alias (__mig_get_reply_port, mig_get_reply_port)
 void
 __mig_dealloc_reply_port (mach_port_t arg)
 {
-  mach_port_t port;
-
-  GETPORT;
-
-  port = reply_port;
-  reply_port = MACH_PORT_NULL;	/* So the mod_refs RPC won't use it.  */
+  mach_port_t port = __hurd_local_reply_port;
+  __hurd_local_reply_port = MACH_PORT_NULL;	/* So the mod_refs RPC won't use it.  */
 
   if (MACH_PORT_VALID (port))
     __mach_port_mod_refs (__mach_task_self (), port,
@@ -73,15 +63,6 @@ weak_alias (__mig_put_reply_port, mig_put_reply_port)
 void
 __mig_init (void *stack)
 {
-  use_threadvar = stack != 0;
-
-  if (use_threadvar)
-    {
-      /* Recycle the reply port used before multithreading was enabled.  */
-      mach_port_t *portloc = (mach_port_t *)
-	__hurd_threadvar_location_from_sp (_HURD_THREADVAR_MIG_REPLY, stack);
-      *portloc = global_reply_port;
-      global_reply_port = MACH_PORT_NULL;
-    }
+  /* Do nothing.  */
 }
 weak_alias (__mig_init, mig_init)
diff --git a/sysdeps/mach/hurd/profil.c b/sysdeps/mach/hurd/profil.c
index b3f201b016..952398b4fa 100644
--- a/sysdeps/mach/hurd/profil.c
+++ b/sysdeps/mach/hurd/profil.c
@@ -141,7 +141,7 @@ weak_alias (__profil, profil)
 static volatile error_t special_profil_failure;
 
 /* Fetch PC samples.  This function must be very careful not to depend
-   on Hurd threadvar variables.  We arrange that by using a special
+   on Hurd TLS variables.  We arrange that by using a special
    stub arranged for at the end of this file. */
 static void
 fetch_samples (void)
@@ -176,7 +176,7 @@ fetch_samples (void)
 }
 
 
-/* This function must be very careful not to depend on Hurd threadvar
+/* This function must be very careful not to depend on Hurd TLS
    variables.  We arrange that by using special stubs arranged for at the
    end of this file. */
 static void
@@ -267,7 +267,7 @@ text_set_element (_hurd_fork_child_hook, fork_profil_child);
    are fatal in profile_waiter anyhow. */
 #define __mig_put_reply_port(foo)
 
-/* Use our static variable instead of the usual threadvar mechanism for
+/* Use our static variable instead of the usual TLS mechanism for
    this. */
 #define __mig_get_reply_port() profil_reply_port