[v7.1,03/13] ARC: Thread Local Storage support

Message ID 20200701000729.16334-1-vgupta@synopsys.com
State Superseded
Headers show
Series
  • Untitled series #27397
Related show

Commit Message

Ben Woodard via Libc-alpha July 1, 2020, 12:07 a.m.
This includes all 4 TLS addressing models
---
   Changes since v7:
     - Deleted unused asm macro THREAD_SELF which references r25
---
 sysdeps/arc/dl-tls.h             |  30 +++++++
 sysdeps/arc/libc-tls.c           |  27 ++++++
 sysdeps/arc/nptl/tcb-offsets.sym |  11 +++
 sysdeps/arc/nptl/tls.h           | 139 +++++++++++++++++++++++++++++++
 sysdeps/arc/stackinfo.h          |  33 ++++++++
 5 files changed, 240 insertions(+)
 create mode 100644 sysdeps/arc/dl-tls.h
 create mode 100644 sysdeps/arc/libc-tls.c
 create mode 100644 sysdeps/arc/nptl/tcb-offsets.sym
 create mode 100644 sysdeps/arc/nptl/tls.h
 create mode 100644 sysdeps/arc/stackinfo.h

-- 
2.20.1

Comments

Ben Woodard via Libc-alpha July 2, 2020, 6:30 p.m. | #1
On 30/06/2020 21:07, Vineet Gupta via Libc-alpha wrote:
> This includes all 4 TLS addressing models

> ---

>    Changes since v7:

>      - Deleted unused asm macro THREAD_SELF which references r25


LGTM with a just a small change below.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


> ---

>  sysdeps/arc/dl-tls.h             |  30 +++++++

>  sysdeps/arc/libc-tls.c           |  27 ++++++

>  sysdeps/arc/nptl/tcb-offsets.sym |  11 +++

>  sysdeps/arc/nptl/tls.h           | 139 +++++++++++++++++++++++++++++++

>  sysdeps/arc/stackinfo.h          |  33 ++++++++

>  5 files changed, 240 insertions(+)

>  create mode 100644 sysdeps/arc/dl-tls.h

>  create mode 100644 sysdeps/arc/libc-tls.c

>  create mode 100644 sysdeps/arc/nptl/tcb-offsets.sym

>  create mode 100644 sysdeps/arc/nptl/tls.h

>  create mode 100644 sysdeps/arc/stackinfo.h

> 

> diff --git a/sysdeps/arc/dl-tls.h b/sysdeps/arc/dl-tls.h

> new file mode 100644

> index 000000000000..0f3626d197c9

> --- /dev/null

> +++ b/sysdeps/arc/dl-tls.h

> @@ -0,0 +1,30 @@

> +/* Thread-local storage handling in the ELF dynamic linker.  ARC version.

> +   Copyright (C) 2020 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

> +   <https://www.gnu.org/licenses/>.  */

> +

> +

> +/* Type used for the representation of TLS information in the GOT.  */

> +typedef struct

> +{

> +  unsigned long int ti_module;

> +  unsigned long int ti_offset;

> +} tls_index;

> +

> +extern void *__tls_get_addr (tls_index *ti);

> +

> +/* Value used for dtv entries for which the allocation is delayed.  */


Ok.

> +#define TLS_DTV_UNALLOCATED	((void *) -1l)

> diff --git a/sysdeps/arc/libc-tls.c b/sysdeps/arc/libc-tls.c

> new file mode 100644

> index 000000000000..234932c29512

> --- /dev/null

> +++ b/sysdeps/arc/libc-tls.c

> @@ -0,0 +1,27 @@

> +/* Thread-local storage handling in the ELF dynamic linker.  ARC version.

> +   Copyright (C) 2020 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

> +   <https://www.gnu.org/licenses/>.  */

> +

> +#include <csu/libc-tls.c>

> +#include <dl-tls.h>

> +

> +void *

> +__tls_get_addr (tls_index *ti)

> +{

> +  dtv_t *dtv = THREAD_DTV ();

> +  return (char *) dtv[1].pointer.val + ti->ti_offset;

> +}


Ok.

> diff --git a/sysdeps/arc/nptl/tcb-offsets.sym b/sysdeps/arc/nptl/tcb-offsets.sym

> new file mode 100644

> index 000000000000..64c432c22e76

> --- /dev/null

> +++ b/sysdeps/arc/nptl/tcb-offsets.sym

> @@ -0,0 +1,11 @@

> +#include <sysdep.h>

> +#include <tls.h>

> +

> +-- Derive offsets relative to the thread register.

> +#define thread_offsetof(mem)	(long)(offsetof (struct pthread, mem) - sizeof (struct pthread))

> +

> +MULTIPLE_THREADS_OFFSET		offsetof (struct pthread, header.multiple_threads)

> +TLS_PRE_TCB_SIZE		sizeof (struct pthread)

> +TLS_TCB_SIZE            	sizeof (tcbhead_t)

> +

> +PTHREAD_TID			offsetof (struct pthread, tid)


Ok.

> diff --git a/sysdeps/arc/nptl/tls.h b/sysdeps/arc/nptl/tls.h

> new file mode 100644

> index 000000000000..40e991444164

> --- /dev/null

> +++ b/sysdeps/arc/nptl/tls.h

> @@ -0,0 +1,139 @@

> +/* Definition for thread-local data handling.  NPTL/ARC version.

> +   Copyright (C) 2020 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

> +   <https://www.gnu.org/licenses/>.  */

> +

> +#ifndef _ARC_NPTL_TLS_H

> +#define _ARC_NPTL_TLS_H	1

> +

> +#include <dl-sysdep.h>

> +

> +#ifndef __ASSEMBLER__

> +

> +# include <stdbool.h>

> +# include <stddef.h>

> +# include <stdint.h>

> +

> +#include <dl-dtv.h>

> +

> +/* Get system call information.  */

> +# include <sysdep.h>

> +

> +/* The TLS blocks start right after the TCB.  */

> +# define TLS_DTV_AT_TP	1

> +# define TLS_TCB_AT_TP	0

> +

> +/* Get the thread descriptor definition.  */

> +# include <nptl/descr.h>

> +

> +typedef struct

> +{

> +  dtv_t *dtv;

> +  uintptr_t pointer_guard;

> +} tcbhead_t;

> +

> +/* This is the size of the initial TCB.  */

> +# define TLS_INIT_TCB_SIZE	sizeof (tcbhead_t)

> +

> +/* Alignment requirements for the initial TCB.  */

> +# define TLS_INIT_TCB_ALIGN	__alignof__ (struct pthread)

> +

> +/* This is the size of the TCB.  */

> +#ifndef TLS_TCB_SIZE

> +# define TLS_TCB_SIZE		sizeof (tcbhead_t)

> +#endif

> +

> +/* Alignment requirements for the TCB.  */

> +# define TLS_TCB_ALIGN		__alignof__ (struct pthread)

> +

> +/* This is the size we need before TCB.  */

> +# define TLS_PRE_TCB_SIZE	sizeof (struct pthread)

> +

> +/* Install the dtv pointer.  The pointer passed is to the element with

> +   index -1 which contain the length.  */

> +# define INSTALL_DTV(tcbp, dtvp) \

> +  (((tcbhead_t *) (tcbp))->dtv = (dtvp) + 1)

> +

> +/* Install new dtv for current thread.  */

> +# define INSTALL_NEW_DTV(dtv) \

> +  (THREAD_DTV() = (dtv))

> +

> +/* Return dtv of given thread descriptor.  */

> +# define GET_DTV(tcbp) \

> +  (((tcbhead_t *) (tcbp))->dtv)

> +

> +/* Code to initially initialize the thread pointer.  */

> +# define TLS_INIT_TP(tcbp)					\

> +  ({                                            		\

> +	long result_var;					\

> +	__builtin_set_thread_pointer (tcbp);     		\

> +	result_var = INTERNAL_SYSCALL (arc_settls, 1, (tcbp));	\


Use INTERNAL_SYSCALL_CALL here (it derives the argument number from
the argument itself).

> +	INTERNAL_SYSCALL_ERROR_P (result_var)			\

> +	? "settls syscall error" : NULL;			\

> +   })

> +

> +/* Value passed to 'clone' for initialization of the thread register.  */

> +# define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) + 1

> +

> +/* Return the address of the dtv for the current thread.  */

> +# define THREAD_DTV() \

> +  (((tcbhead_t *) __builtin_thread_pointer ())->dtv)

> +

> +/* Return the thread descriptor for the current thread.  */

> +# define THREAD_SELF \

> + ((struct pthread *)__builtin_thread_pointer () - 1)

> +

> +/* Magic for libthread_db to know how to do THREAD_SELF.  */

> +# define DB_THREAD_SELF \

> +  CONST_THREAD_AREA (32, sizeof (struct pthread))

> +

> +/* Access to data in the thread descriptor is easy.  */

> +# define THREAD_GETMEM(descr, member) \

> +  descr->member

> +# define THREAD_GETMEM_NC(descr, member, idx) \

> +  descr->member[idx]

> +# define THREAD_SETMEM(descr, member, value) \

> +  descr->member = (value)

> +# define THREAD_SETMEM_NC(descr, member, idx, value) \

> +  descr->member[idx] = (value)

> +

> +/* Get and set the global scope generation counter in struct pthread.  */

> +#define THREAD_GSCOPE_IN_TCB      1

> +#define THREAD_GSCOPE_FLAG_UNUSED 0

> +#define THREAD_GSCOPE_FLAG_USED   1

> +#define THREAD_GSCOPE_FLAG_WAIT   2

> +#define THREAD_GSCOPE_RESET_FLAG() \

> +  do									     \

> +    { int __res								     \

> +	= atomic_exchange_rel (&THREAD_SELF->header.gscope_flag,	     \

> +			       THREAD_GSCOPE_FLAG_UNUSED);		     \

> +      if (__res == THREAD_GSCOPE_FLAG_WAIT)				     \

> +	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);   \

> +    }									     \

> +  while (0)

> +#define THREAD_GSCOPE_SET_FLAG() \

> +  do									     \

> +    {									     \

> +      THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;	     \

> +      atomic_write_barrier ();						     \

> +    }									     \

> +  while (0)

> +#define THREAD_GSCOPE_WAIT() \

> +  GL(dl_wait_lookup_done) ()

> +

> +#endif /* !__ASSEMBLER__ */

> +

> +#endif	/* tls.h */


Ok.

> diff --git a/sysdeps/arc/stackinfo.h b/sysdeps/arc/stackinfo.h

> new file mode 100644

> index 000000000000..02ae1cd8c425

> --- /dev/null

> +++ b/sysdeps/arc/stackinfo.h

> @@ -0,0 +1,33 @@

> +/* Stack environment definitions for ARC.

> +   Copyright (C) 2020 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

> +   <https://www.gnu.org/licenses/>.  */

> +

> +/* This file contains a bit of information about the stack allocation

> +   of the processor.  */

> +

> +#ifndef _STACKINFO_H

> +#define _STACKINFO_H	1

> +

> +#include <elf.h>

> +

> +/* On ARC the stack grows down.  */

> +#define _STACK_GROWS_DOWN	1

> +

> +/* Default to a non-executable stack.  */

> +#define DEFAULT_STACK_PERMS (PF_R|PF_W)

> +

> +#endif	/* stackinfo.h */

> 


Ok.
Ben Woodard via Libc-alpha July 3, 2020, 12:04 a.m. | #2
On 7/2/20 11:30 AM, Adhemerval Zanella via Libc-alpha wrote:

> On 30/06/2020 21:07, Vineet Gupta via Libc-alpha wrote:

>> This includes all 4 TLS addressing models

>> ---

>>    Changes since v7:

>>      - Deleted unused asm macro THREAD_SELF which references r25

> 

> LGTM with a just a small change below.

> 

> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


>> +

>> +/* Code to initially initialize the thread pointer.  */

>> +# define TLS_INIT_TP(tcbp)					\

>> +  ({                                            		\

>> +	long result_var;					\

>> +	__builtin_set_thread_pointer (tcbp);     		\

>> +	result_var = INTERNAL_SYSCALL (arc_settls, 1, (tcbp));	\

> 

> Use INTERNAL_SYSCALL_CALL here (it derives the argument number from

> the argument itself).


Fixed.

Thx,
-Vineet

Patch

diff --git a/sysdeps/arc/dl-tls.h b/sysdeps/arc/dl-tls.h
new file mode 100644
index 000000000000..0f3626d197c9
--- /dev/null
+++ b/sysdeps/arc/dl-tls.h
@@ -0,0 +1,30 @@ 
+/* Thread-local storage handling in the ELF dynamic linker.  ARC version.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+
+/* Type used for the representation of TLS information in the GOT.  */
+typedef struct
+{
+  unsigned long int ti_module;
+  unsigned long int ti_offset;
+} tls_index;
+
+extern void *__tls_get_addr (tls_index *ti);
+
+/* Value used for dtv entries for which the allocation is delayed.  */
+#define TLS_DTV_UNALLOCATED	((void *) -1l)
diff --git a/sysdeps/arc/libc-tls.c b/sysdeps/arc/libc-tls.c
new file mode 100644
index 000000000000..234932c29512
--- /dev/null
+++ b/sysdeps/arc/libc-tls.c
@@ -0,0 +1,27 @@ 
+/* Thread-local storage handling in the ELF dynamic linker.  ARC version.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <csu/libc-tls.c>
+#include <dl-tls.h>
+
+void *
+__tls_get_addr (tls_index *ti)
+{
+  dtv_t *dtv = THREAD_DTV ();
+  return (char *) dtv[1].pointer.val + ti->ti_offset;
+}
diff --git a/sysdeps/arc/nptl/tcb-offsets.sym b/sysdeps/arc/nptl/tcb-offsets.sym
new file mode 100644
index 000000000000..64c432c22e76
--- /dev/null
+++ b/sysdeps/arc/nptl/tcb-offsets.sym
@@ -0,0 +1,11 @@ 
+#include <sysdep.h>
+#include <tls.h>
+
+-- Derive offsets relative to the thread register.
+#define thread_offsetof(mem)	(long)(offsetof (struct pthread, mem) - sizeof (struct pthread))
+
+MULTIPLE_THREADS_OFFSET		offsetof (struct pthread, header.multiple_threads)
+TLS_PRE_TCB_SIZE		sizeof (struct pthread)
+TLS_TCB_SIZE            	sizeof (tcbhead_t)
+
+PTHREAD_TID			offsetof (struct pthread, tid)
diff --git a/sysdeps/arc/nptl/tls.h b/sysdeps/arc/nptl/tls.h
new file mode 100644
index 000000000000..40e991444164
--- /dev/null
+++ b/sysdeps/arc/nptl/tls.h
@@ -0,0 +1,139 @@ 
+/* Definition for thread-local data handling.  NPTL/ARC version.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _ARC_NPTL_TLS_H
+#define _ARC_NPTL_TLS_H	1
+
+#include <dl-sysdep.h>
+
+#ifndef __ASSEMBLER__
+
+# include <stdbool.h>
+# include <stddef.h>
+# include <stdint.h>
+
+#include <dl-dtv.h>
+
+/* Get system call information.  */
+# include <sysdep.h>
+
+/* The TLS blocks start right after the TCB.  */
+# define TLS_DTV_AT_TP	1
+# define TLS_TCB_AT_TP	0
+
+/* Get the thread descriptor definition.  */
+# include <nptl/descr.h>
+
+typedef struct
+{
+  dtv_t *dtv;
+  uintptr_t pointer_guard;
+} tcbhead_t;
+
+/* This is the size of the initial TCB.  */
+# define TLS_INIT_TCB_SIZE	sizeof (tcbhead_t)
+
+/* Alignment requirements for the initial TCB.  */
+# define TLS_INIT_TCB_ALIGN	__alignof__ (struct pthread)
+
+/* This is the size of the TCB.  */
+#ifndef TLS_TCB_SIZE
+# define TLS_TCB_SIZE		sizeof (tcbhead_t)
+#endif
+
+/* Alignment requirements for the TCB.  */
+# define TLS_TCB_ALIGN		__alignof__ (struct pthread)
+
+/* This is the size we need before TCB.  */
+# define TLS_PRE_TCB_SIZE	sizeof (struct pthread)
+
+/* Install the dtv pointer.  The pointer passed is to the element with
+   index -1 which contain the length.  */
+# define INSTALL_DTV(tcbp, dtvp) \
+  (((tcbhead_t *) (tcbp))->dtv = (dtvp) + 1)
+
+/* Install new dtv for current thread.  */
+# define INSTALL_NEW_DTV(dtv) \
+  (THREAD_DTV() = (dtv))
+
+/* Return dtv of given thread descriptor.  */
+# define GET_DTV(tcbp) \
+  (((tcbhead_t *) (tcbp))->dtv)
+
+/* Code to initially initialize the thread pointer.  */
+# define TLS_INIT_TP(tcbp)					\
+  ({                                            		\
+	long result_var;					\
+	__builtin_set_thread_pointer (tcbp);     		\
+	result_var = INTERNAL_SYSCALL (arc_settls, 1, (tcbp));	\
+	INTERNAL_SYSCALL_ERROR_P (result_var)			\
+	? "settls syscall error" : NULL;			\
+   })
+
+/* Value passed to 'clone' for initialization of the thread register.  */
+# define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) + 1
+
+/* Return the address of the dtv for the current thread.  */
+# define THREAD_DTV() \
+  (((tcbhead_t *) __builtin_thread_pointer ())->dtv)
+
+/* Return the thread descriptor for the current thread.  */
+# define THREAD_SELF \
+ ((struct pthread *)__builtin_thread_pointer () - 1)
+
+/* Magic for libthread_db to know how to do THREAD_SELF.  */
+# define DB_THREAD_SELF \
+  CONST_THREAD_AREA (32, sizeof (struct pthread))
+
+/* Access to data in the thread descriptor is easy.  */
+# define THREAD_GETMEM(descr, member) \
+  descr->member
+# define THREAD_GETMEM_NC(descr, member, idx) \
+  descr->member[idx]
+# define THREAD_SETMEM(descr, member, value) \
+  descr->member = (value)
+# define THREAD_SETMEM_NC(descr, member, idx, value) \
+  descr->member[idx] = (value)
+
+/* Get and set the global scope generation counter in struct pthread.  */
+#define THREAD_GSCOPE_IN_TCB      1
+#define THREAD_GSCOPE_FLAG_UNUSED 0
+#define THREAD_GSCOPE_FLAG_USED   1
+#define THREAD_GSCOPE_FLAG_WAIT   2
+#define THREAD_GSCOPE_RESET_FLAG() \
+  do									     \
+    { int __res								     \
+	= atomic_exchange_rel (&THREAD_SELF->header.gscope_flag,	     \
+			       THREAD_GSCOPE_FLAG_UNUSED);		     \
+      if (__res == THREAD_GSCOPE_FLAG_WAIT)				     \
+	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);   \
+    }									     \
+  while (0)
+#define THREAD_GSCOPE_SET_FLAG() \
+  do									     \
+    {									     \
+      THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;	     \
+      atomic_write_barrier ();						     \
+    }									     \
+  while (0)
+#define THREAD_GSCOPE_WAIT() \
+  GL(dl_wait_lookup_done) ()
+
+#endif /* !__ASSEMBLER__ */
+
+#endif	/* tls.h */
diff --git a/sysdeps/arc/stackinfo.h b/sysdeps/arc/stackinfo.h
new file mode 100644
index 000000000000..02ae1cd8c425
--- /dev/null
+++ b/sysdeps/arc/stackinfo.h
@@ -0,0 +1,33 @@ 
+/* Stack environment definitions for ARC.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+/* This file contains a bit of information about the stack allocation
+   of the processor.  */
+
+#ifndef _STACKINFO_H
+#define _STACKINFO_H	1
+
+#include <elf.h>
+
+/* On ARC the stack grows down.  */
+#define _STACK_GROWS_DOWN	1
+
+/* Default to a non-executable stack.  */
+#define DEFAULT_STACK_PERMS (PF_R|PF_W)
+
+#endif	/* stackinfo.h */