[09/21] ARC: Linux ABI

Message ID 1545167083-16764-10-git-send-email-vgupta@synopsys.com
State New
Headers show
Series
  • glibc port to ARC processors
Related show

Commit Message

Vineet Gupta Dec. 18, 2018, 9:04 p.m.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

---
 ChangeLog                                     | 15 +++++
 sysdeps/arc/nptl/pthread-offsets.h            |  5 ++
 sysdeps/arc/nptl/pthreaddef.h                 | 32 +++++++++
 sysdeps/unix/sysv/linux/arc/bits/procfs-id.h  | 25 +++++++
 sysdeps/unix/sysv/linux/arc/bits/procfs.h     | 35 ++++++++++
 sysdeps/unix/sysv/linux/arc/bits/sigaction.h  | 85 ++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/getcontext.S      | 65 +++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/makecontext.c     | 74 +++++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/setcontext.S      | 93 +++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/sigcontextinfo.h  | 23 +++++++
 sysdeps/unix/sysv/linux/arc/swapcontext.S     | 92 ++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/sys/cachectl.h    | 36 +++++++++++
 sysdeps/unix/sysv/linux/arc/sys/ucontext.h    | 71 ++++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/sys/user.h        | 32 +++++++++
 sysdeps/unix/sysv/linux/arc/ucontext-macros.h | 29 +++++++++
 sysdeps/unix/sysv/linux/arc/ucontext_i.sym    | 20 ++++++
 16 files changed, 732 insertions(+)
 create mode 100644 sysdeps/arc/nptl/pthread-offsets.h
 create mode 100644 sysdeps/arc/nptl/pthreaddef.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/bits/procfs-id.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/bits/procfs.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/bits/sigaction.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/getcontext.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/makecontext.c
 create mode 100644 sysdeps/unix/sysv/linux/arc/setcontext.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/sigcontextinfo.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/swapcontext.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/sys/cachectl.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/sys/ucontext.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/sys/user.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/ucontext-macros.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/ucontext_i.sym

-- 
2.7.4

Comments

Joseph Myers Dec. 18, 2018, 11:38 p.m. | #1
On Tue, 18 Dec 2018, Vineet Gupta wrote:

> +typedef unsigned short int __pr_uid_t;

> +typedef unsigned short int __pr_gid_t;


Are you sure?  I don't see an ARC-specific definition of __kernel_uid_t or 
__kernel_gid_t in the Linux kernel at all (which would mean unsigned int 
is actually used and you don't need this header at all).

> diff --git a/sysdeps/unix/sysv/linux/arc/bits/sigaction.h b/sysdeps/unix/sysv/linux/arc/bits/sigaction.h


I wouldn't expect new architectures to have their own bits/sigaction.h.  
Rather, I'd expect them to use the generic bits/sigaction.h and the 
generic code to convert from the userspace struct sigaction to the kernel 
version.

> +#ifdef __USE_MISC

> +# define __ctx(fld) fld

> +#else

> +# define __ctx(fld) __ ## fld

> +#endif


New ports should just use namespace-clean field names here 
unconditionally.  The __ctx macros with __USE_MISC conditionals are purely 
for maximum API-compatibility for existing ports that needed to be fixed 
to make them namespace-clean.

-- 
Joseph S. Myers
joseph@codesourcery.com
Vineet Gupta Dec. 19, 2018, 7:57 p.m. | #2
On 12/18/18 3:38 PM, Joseph Myers wrote:
> On Tue, 18 Dec 2018, Vineet Gupta wrote:

> 

>> +typedef unsigned short int __pr_uid_t;

>> +typedef unsigned short int __pr_gid_t;

> 

> Are you sure?  


No I'm not :-) There were some interim sweeping changes in this area since when I
started so this might indeed be redundant as you say.

> I don't see an ARC-specific definition of __kernel_uid_t or 

> __kernel_gid_t in the Linux kernel at all (which would mean unsigned int 

> is actually used and you don't need this header at all).


I'll check.

>> diff --git a/sysdeps/unix/sysv/linux/arc/bits/sigaction.h b/sysdeps/unix/sysv/linux/arc/bits/sigaction.h

> 

> I wouldn't expect new architectures to have their own bits/sigaction.h.  

> Rather, I'd expect them to use the generic bits/sigaction.h and the 

> generic code to convert from the userspace struct sigaction to the kernel 

> version.


So this is further to the other thread about generic sigaction (sorry for
cross-post). Indeed with switch to generic sigaction this may not be required.
*However* the layouts of generic userspace sigaction are different from kernel's.
Just to rehash (notes for myself really)

1. user exported struct

struct sigaction
  {
    __sighandler_t sa_handler;
    __sigset_t sa_mask;
    int sa_flags;
    void (*sa_restorer) (void);
  };

2. Linux kernel UAPI struct sigaction / glibc kernel_sigaction

struct sigaction {
	__sighandler_t sa_handler;
	unsigned long sa_flags;
	__sigrestore_t sa_restorer;
	sigset_t sa_mask;  /* mask last for extensibility */
};

Since they don't match and we can't possibly change kernel_sigaction, a future
optimization implies changing #1 which has ABI implications at which point it has
diminished or NO returns.

So perhaps we keep the ARC header above, with matching layout, while switching to
generic sigaction() still. OK ?

>> +#ifdef __USE_MISC

>> +# define __ctx(fld) fld

>> +#else

>> +# define __ctx(fld) __ ## fld

>> +#endif

> 

> New ports should just use namespace-clean field names here 

> unconditionally.  The __ctx macros with __USE_MISC conditionals are purely 

> for maximum API-compatibility for existing ports that needed to be fixed 

> to make them namespace-clean.


OK, fixed this.

Thx,
-Vineet
Joseph Myers Dec. 19, 2018, 8:36 p.m. | #3
On Wed, 19 Dec 2018, Vineet Gupta wrote:

> So perhaps we keep the ARC header above, with matching layout, while 

> switching to generic sigaction() still. OK ?


If the different userspace layout is better, it should be better for all 
future ports as well.

Duplicating all the SA_* constants in architecture-specific headers, even 
when those architectures don't actually have different values of those 
constants, is bad, especially since there is logic about which __USE_* 
macros get which SA_* defined which then needs to be duplicated.

So what this suggests to me is a preliminary patch series to unify 
bits/sigaction.h headers - there might be one header for SA_* constants 
(architecture-specific variants only when needed), one for SIG_* constants 
(architecture-specific variants only when needed), and one for the ways in 
which the layout of the userspace struct sigaction can vary (defining 
macros that the unified bits/sigaction.h then uses to control the layout - 
cf. the siginfo unification a while back).

Initially, the default version of that last header would correspond to the 
existing sysdeps/unix/sysv/linux/bits/sigaction.h header - however, if you 
get consensus for a different layout as the default for new architectures, 
the default would change and all existing architectures that use the 
current default layout would get copies of the new bits/ header configured 
to keep the old layout.  (Variants are possible to reduce the number of 
architectures needing architecture-specific copies as a result of the 
changed default.  For example, you could have the new default only in 
sysdeps/unix/sysv/linux/generic not sysdeps/unix/sysv/linux/ and then only 
existing asm-generic architectures (aarch64 nios2 riscv) would need to 
override back to the old default layout.)

-- 
Joseph S. Myers
joseph@codesourcery.com
Vineet Gupta Dec. 21, 2018, 11:06 p.m. | #4
On 12/19/18 12:36 PM, Joseph Myers wrote:
> On Wed, 19 Dec 2018, Vineet Gupta wrote:

> 

>> So perhaps we keep the ARC header above, with matching layout, while 

>> switching to generic sigaction() still. OK ?

> 

> If the different userspace layout is better, it should be better for all 

> future ports as well.

> 

> Duplicating all the SA_* constants in architecture-specific headers, even 

> when those architectures don't actually have different values of those 

> constants, is bad, especially since there is logic about which __USE_* 

> macros get which SA_* defined which then needs to be duplicated.


Totally agree.

> So what this suggests to me is a preliminary patch series to unify 

> bits/sigaction.h headers - there might be one header for SA_* constants 

> (architecture-specific variants only when needed), one for SIG_* constants 

> (architecture-specific variants only when needed), and one for the ways in 

> which the layout of the userspace struct sigaction can vary (defining 

> macros that the unified bits/sigaction.h then uses to control the layout - 

> cf. the siginfo unification a while back).


Actually this can be simplified. Given the asm-generic syscall ABI, we are anyhow
locked into SA_* or SIG_* and kernel side sigaction, the only variant is user
facing struct sigaction. I suppose we could leave it at that given that only 1
syscall sigaction is affected. The bigger bang for the buck will the reduction of
sizeof(sigset_t) - purely from amount of memory any sig* call needs to
read/write/copy.

I'll follow Adhemerval's suggestion of arch-specific __sigset_t.h which seems
doable w/o much pain.

> Initially, the default version of that last header would correspond to the 

> existing sysdeps/unix/sysv/linux/bits/sigaction.h header - however, if you 

> get consensus for a different layout as the default for new architectures, 

> the default would change and all existing architectures that use the 

> current default layout would get copies of the new bits/ header configured 

> to keep the old layout.  (Variants are possible to reduce the number of 

> architectures needing architecture-specific copies as a result of the 

> changed default.  For example, you could have the new default only in 

> sysdeps/unix/sysv/linux/generic not sysdeps/unix/sysv/linux/ and then only 

> existing asm-generic architectures (aarch64 nios2 riscv) would need to 

> override back to the old default layout.)


Yes this will require a needless churn all over, just for 1 syscall.

Patch

diff --git a/ChangeLog b/ChangeLog
index 08a3ac7e8064..ca010c356597 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -56,6 +56,21 @@ 
 	* sysdeps/unix/sysv/linux/arc/sysdep.c: New file.
 	* sysdeps/unix/sysv/linux/arc/sysdep.h: New file.
 	* sysdeps/unix/sysv/linux/arc/vfork.S: New file.
+	* sysdeps/arc/nptl/pthread-offsets.h: New file.
+	* sysdeps/arc/nptl/pthreaddef.h: New file.
+	* sysdeps/unix/sysv/linux/arc/bits/procfs-id.h: New file.
+	* sysdeps/unix/sysv/linux/arc/bits/procfs.h: New file.
+	* sysdeps/unix/sysv/linux/arc/bits/sigaction.h: New file.
+	* sysdeps/unix/sysv/linux/arc/getcontext.S: New file.
+	* sysdeps/unix/sysv/linux/arc/makecontext.c: New file.
+	* sysdeps/unix/sysv/linux/arc/setcontext.S: New file.
+	* sysdeps/unix/sysv/linux/arc/sigcontextinfo.h: New file.
+	* sysdeps/unix/sysv/linux/arc/swapcontext.S: New file.
+	* sysdeps/unix/sysv/linux/arc/sys/cachectl.h: New file.
+	* sysdeps/unix/sysv/linux/arc/sys/ucontext.h: New file.
+	* sysdeps/unix/sysv/linux/arc/sys/user.h: New file.
+	* sysdeps/unix/sysv/linux/arc/ucontext-macros.h: New file.
+	* sysdeps/unix/sysv/linux/arc/ucontext_i.sym: New file.
 
 2018-12-17  Joseph Myers  <joseph@codesourcery.com>
 
diff --git a/sysdeps/arc/nptl/pthread-offsets.h b/sysdeps/arc/nptl/pthread-offsets.h
new file mode 100644
index 000000000000..9617354dc7e3
--- /dev/null
+++ b/sysdeps/arc/nptl/pthread-offsets.h
@@ -0,0 +1,5 @@ 
+#define __PTHREAD_MUTEX_NUSERS_OFFSET   16
+#define __PTHREAD_MUTEX_KIND_OFFSET     12
+#define __PTHREAD_MUTEX_SPINS_OFFSET    20
+#define __PTHREAD_MUTEX_ELISION_OFFSET  22
+#define __PTHREAD_MUTEX_LIST_OFFSET     20
diff --git a/sysdeps/arc/nptl/pthreaddef.h b/sysdeps/arc/nptl/pthreaddef.h
new file mode 100644
index 000000000000..41e13c53038c
--- /dev/null
+++ b/sysdeps/arc/nptl/pthreaddef.h
@@ -0,0 +1,32 @@ 
+/* pthread machine parameter definitions, ARC version.
+   Copyright (C) 2002-2018 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/>.  */
+
+/* Default stack size.  */
+#define ARCH_STACK_DEFAULT_SIZE	(2 * 1024 * 1024)
+
+/* Required stack pointer alignment at beginning.  */
+#define STACK_ALIGN		4
+
+/* Minimal stack size after allocating thread descriptor and guard size.  */
+#define MINIMAL_REST_STACK	2048
+
+/* Alignment requirement for TCB.  */
+#define TCB_ALIGNMENT		4
+
+/* Location of current stack frame.  */
+#define CURRENT_STACK_FRAME	__builtin_frame_address (0)
diff --git a/sysdeps/unix/sysv/linux/arc/bits/procfs-id.h b/sysdeps/unix/sysv/linux/arc/bits/procfs-id.h
new file mode 100644
index 000000000000..d0192fcbc36e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/bits/procfs-id.h
@@ -0,0 +1,25 @@ 
+/* Types of pr_uid and pr_gid in struct elf_prpsinfo.  ARC version.
+   Copyright (C) 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 _SYS_PROCFS_H
+# error "Never include <bits/procfs-id.h> directly; use <sys/procfs.h> instead."
+#endif
+
+typedef unsigned short int __pr_uid_t;
+typedef unsigned short int __pr_gid_t;
diff --git a/sysdeps/unix/sysv/linux/arc/bits/procfs.h b/sysdeps/unix/sysv/linux/arc/bits/procfs.h
new file mode 100644
index 000000000000..a3315beddb37
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/bits/procfs.h
@@ -0,0 +1,35 @@ 
+/* Types for registers for sys/procfs.h.  ARC version.
+   Copyright (C) 1996-2018 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 _SYS_PROCFS_H
+# error "Never include <bits/procfs.h> directly; use <sys/procfs.h> instead."
+#endif
+
+#include <sys/ucontext.h>
+
+/* And the whole bunch of them.  We could have used `struct
+   user_regs' directly in the typedef, but tradition says that
+   the register set is an array, which does have some peculiar
+   semantics, so leave it that way.  */
+#define ELF_NGREG (sizeof (struct user_regs_struct) / sizeof(elf_greg_t))
+
+typedef unsigned long int elf_greg_t;
+typedef unsigned long int elf_gregset_t[ELF_NGREG];
+
+/* There's no seperate floating point reg file in ARCv2  */
+typedef struct { } elf_fpregset_t;
diff --git a/sysdeps/unix/sysv/linux/arc/bits/sigaction.h b/sysdeps/unix/sysv/linux/arc/bits/sigaction.h
new file mode 100644
index 000000000000..47e86c06ce98
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/bits/sigaction.h
@@ -0,0 +1,85 @@ 
+/* The proper definitions for Linux's sigaction.
+   Copyright (C) 1993-2018 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 _BITS_SIGACTION_H
+#define _BITS_SIGACTION_H 1
+
+#ifndef _SIGNAL_H
+# error "Never include <bits/sigaction.h> directly; use <signal.h> instead."
+#endif
+
+/* Structure describing the action to be taken when a signal arrives.
+ * The generic struct is NOT ABI compatible with asm-generic Linux syscall variant*/
+
+struct sigaction
+  {
+    /* Signal handler.  */
+#if defined __USE_POSIX199309 || defined __USE_XOPEN_EXTENDED
+    union
+      {
+	/* Used if SA_SIGINFO is not set.  */
+	__sighandler_t sa_handler;
+	/* Used if SA_SIGINFO is set.  */
+	void (*sa_sigaction) (int, siginfo_t *, void *);
+      }
+    __sigaction_handler;
+# define sa_handler	__sigaction_handler.sa_handler
+# define sa_sigaction	__sigaction_handler.sa_sigaction
+#else
+    __sighandler_t sa_handler;
+#endif
+
+    /* Special flags.  */
+    int sa_flags;
+
+    /* Restore handler.  */
+    void (*sa_restorer) (void);
+
+    /* Additional set of signals to be blocked.  */
+    __sigset_t sa_mask;
+  };
+
+/* Bits in `sa_flags'.  */
+#define	SA_NOCLDSTOP  1		 /* Don't send SIGCHLD when children stop.  */
+#define SA_NOCLDWAIT  2		 /* Don't create zombie on child death.  */
+#define SA_SIGINFO    4		 /* Invoke signal-catching function with
+				    three arguments instead of one.  */
+#if defined __USE_XOPEN_EXTENDED || defined __USE_MISC
+# define SA_ONSTACK   0x08000000 /* Use signal stack by using `sa_restorer'. */
+#endif
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+# define SA_RESTART   0x10000000 /* Restart syscall on signal return.  */
+# define SA_NODEFER   0x40000000 /* Don't automatically block the signal when
+				    its handler is being executed.  */
+# define SA_RESETHAND 0x80000000 /* Reset to SIG_DFL on entry to handler.  */
+#endif
+#ifdef __USE_MISC
+# define SA_INTERRUPT 0x20000000 /* Historical no-op.  */
+
+/* Some aliases for the SA_ constants.  */
+# define SA_NOMASK    SA_NODEFER
+# define SA_ONESHOT   SA_RESETHAND
+# define SA_STACK     SA_ONSTACK
+#endif
+
+/* Values for the HOW argument to `sigprocmask'.  */
+#define	SIG_BLOCK     0		 /* Block signals.  */
+#define	SIG_UNBLOCK   1		 /* Unblock signals.  */
+#define	SIG_SETMASK   2		 /* Set the set of blocked signals.  */
+
+#endif
\ No newline at end of file
diff --git a/sysdeps/unix/sysv/linux/arc/getcontext.S b/sysdeps/unix/sysv/linux/arc/getcontext.S
new file mode 100644
index 000000000000..af31f581e846
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/getcontext.S
@@ -0,0 +1,65 @@ 
+/* Save current context for ARC
+   Copyright (C) 2009-2018 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/>.  */
+
+#include "ucontext-macros.h"
+
+/* int getcontext (ucontext_t *ucp)
+
+  Save machine context in @ucp and return 0 on success, -1 on error
+    - saves callee saved registers only
+    - layout mandated by uncontext_t:m_context (hence different from setjmp)
+*/
+
+ENTRY(__getcontext)
+
+	/* callee saved registers */
+	SAVE_REG(r13,   r0, 37)
+	SAVE_REG(r14,   r0, 36)
+	SAVE_REG(r15,   r0, 35)
+	SAVE_REG(r16,   r0, 34)
+	SAVE_REG(r17,   r0, 33)
+	SAVE_REG(r18,   r0, 32)
+	SAVE_REG(r19,   r0, 31)
+	SAVE_REG(r20,   r0, 30)
+	SAVE_REG(r21,   r0, 29)
+	SAVE_REG(r22,   r0, 28)
+	SAVE_REG(r23,   r0, 27)
+	SAVE_REG(r24,   r0, 26)
+	SAVE_REG(r25,   r0, 25)
+
+	SAVE_REG(blink, r0,  7)
+	SAVE_REG(fp,    r0,  8)
+	SAVE_REG(sp,    r0, 23)
+
+	/* save 0 in r0 placeholder to return 0 when this @ucp activated */
+	mov r9, 0
+	SAVE_REG(r9,    r0, 22)
+
+	/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
+	mov r3, _NSIG8
+	add r2, r0, UCONTEXT_SIGMASK
+	mov r1, 0
+	mov r0, SIG_BLOCK
+	mov r8, __NR_rt_sigprocmask
+	ARC_TRAP_INSN
+	brhi    r0, -1024, .Lcall_syscall_err
+	j.d	[blink]
+	mov r0, 0	; success ; error case handled in .Lcall_syscall_err
+
+PSEUDO_END(__getcontext)
+weak_alias(__getcontext, getcontext)
diff --git a/sysdeps/unix/sysv/linux/arc/makecontext.c b/sysdeps/unix/sysv/linux/arc/makecontext.c
new file mode 100644
index 000000000000..7018bed9d64a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/makecontext.c
@@ -0,0 +1,74 @@ 
+/* Create new context for ARC
+   Copyright (C) 2015-2018 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/>.  */
+
+#include <sysdep.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <sys/ucontext.h>
+
+void
+__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
+{
+  extern void __startcontext (void) attribute_hidden;
+  unsigned long sp, *r;
+  va_list vl;
+  int i, reg_args, stack_args;
+
+  sp = ((unsigned long) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & ~7;
+
+  ucp->uc_mcontext.scratch.sp = sp;
+  ucp->uc_mcontext.scratch.fp = 0;
+
+  /* __startcontext is sort of trampoline to invoke @func
+   *  From setcontext() pov, the resume address is __startcontext,
+   *  set it up in BLINK place holder*/
+  ucp->uc_mcontext.scratch.blink = (unsigned long) &__startcontext;
+
+  /* __startcontext passed 2 types of args
+   *    - args to @func setup in canonical r0-r7
+   *    - @func itself in r9, and next function in r10
+   */
+  ucp->uc_mcontext.callee.r13 = (unsigned long) func;
+  ucp->uc_mcontext.callee.r14 = (unsigned long) ucp->uc_link;
+
+  r = &ucp->uc_mcontext.scratch.r0;
+
+  va_start (vl, argc);
+
+  reg_args = argc > 8 ? 8 : argc;
+  for (i = 0; i < reg_args; i++) {
+      *r-- = va_arg(vl, unsigned long);
+  }
+
+  stack_args = argc - reg_args;
+
+  if (__glibc_unlikely(stack_args > 0)) {
+
+    sp -=  stack_args * sizeof (unsigned long);
+    ucp->uc_mcontext.scratch.sp = sp;
+    r = (unsigned long *)sp;
+
+    for (i = 0; i < stack_args; i++) {
+        *r++ = va_arg(vl, unsigned long);
+    }
+  }
+
+  va_end (vl);
+}
+
+weak_alias (__makecontext, makecontext)
diff --git a/sysdeps/unix/sysv/linux/arc/setcontext.S b/sysdeps/unix/sysv/linux/arc/setcontext.S
new file mode 100644
index 000000000000..3f503c661d95
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/setcontext.S
@@ -0,0 +1,93 @@ 
+/* Set current context for ARC
+   Copyright (C) 2009-2018 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/>.  */
+
+#include "ucontext-macros.h"
+
+/*
+   int setcontext (const ucontext_t *ucp)
+     - Restores the machine context in @ucp and resumes execution
+       (doesn't return to caller)
+*/
+
+ENTRY(__setcontext)
+
+	mov  r9, r0	/* stash @ucp across syscall */
+
+	/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
+	mov  r3, _NSIG8
+	mov  r2, 0
+	add  r1, r0, UCONTEXT_SIGMASK
+	mov  r0, SIG_SETMASK
+	mov  r8, __NR_rt_sigprocmask
+	ARC_TRAP_INSN
+	brhi r0, -1024, .Lcall_syscall_err
+
+	/* restore scratch/arg regs for makecontext() case */
+	LOAD_REG(r0,    r9, 22)
+	LOAD_REG(r1,    r9, 21)
+	LOAD_REG(r2,    r9, 20)
+	LOAD_REG(r3,    r9, 19)
+	LOAD_REG(r4,    r9, 18)
+	LOAD_REG(r5,    r9, 17)
+	LOAD_REG(r6,    r9, 16)
+	LOAD_REG(r7,    r9, 15)
+
+	/* restore callee saved registers */
+	LOAD_REG(r13,   r9, 37)
+	LOAD_REG(r14,   r9, 36)
+	LOAD_REG(r15,   r9, 35)
+	LOAD_REG(r16,   r9, 34)
+	LOAD_REG(r17,   r9, 33)
+	LOAD_REG(r18,   r9, 32)
+	LOAD_REG(r19,   r9, 31)
+	LOAD_REG(r20,   r9, 30)
+	LOAD_REG(r21,   r9, 29)
+	LOAD_REG(r22,   r9, 28)
+	LOAD_REG(r23,   r9, 27)
+	LOAD_REG(r24,   r9, 26)
+	LOAD_REG(r25,   r9, 25)
+
+	LOAD_REG(blink, r9,  7)
+	LOAD_REG(fp,    r9,  8)
+	LOAD_REG(sp,    r9, 23)
+
+	j    [blink]
+
+PSEUDO_END(__setcontext)
+weak_alias(__setcontext, setcontext)
+
+
+/*
+   Helper for activating makecontext() created context
+     - r13 has @func, r14 has uc_link
+*/
+
+ENTRY(__startcontext)
+
+        /* call user @func, loaded in r13 by setcontext() */
+        jl   [r13]
+
+        /* if uc_link (r14) call setcontext with that */
+        mov  r0, r14
+        breq r0, 0, 1f
+
+        bl   __setcontext
+1:
+        /* exit with status 0 */
+        b    HIDDEN_JUMPTARGET(exit)
+END(__startcontext)
diff --git a/sysdeps/unix/sysv/linux/arc/sigcontextinfo.h b/sysdeps/unix/sysv/linux/arc/sigcontextinfo.h
new file mode 100644
index 000000000000..852bbd96d47f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sigcontextinfo.h
@@ -0,0 +1,23 @@ 
+/* ARC definitions for signal handling calling conventions.
+   Copyright (C) 2017-2018 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/>.  */
+
+#include <sys/ucontext.h>
+#include "kernel-features.h"
+
+#define SIGCONTEXT int _code, struct ucontext_t *
+#define GET_PC(ctx)    ((void *) (ctx)->uc_mcontext.scratch.ret)
diff --git a/sysdeps/unix/sysv/linux/arc/swapcontext.S b/sysdeps/unix/sysv/linux/arc/swapcontext.S
new file mode 100644
index 000000000000..ad6bf70ab5e2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/swapcontext.S
@@ -0,0 +1,92 @@ 
+/* Save and set current context for ARC
+   Copyright (C) 2009-2018 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/>.  */
+
+#include "ucontext-macros.h"
+
+/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
+
+ENTRY(__swapcontext)
+
+	/* save context into @oucp pointed to by r0 */
+
+	SAVE_REG(r13,   r0, 37)
+	SAVE_REG(r14,   r0, 36)
+	SAVE_REG(r15,   r0, 35)
+	SAVE_REG(r16,   r0, 34)
+	SAVE_REG(r17,   r0, 33)
+	SAVE_REG(r18,   r0, 32)
+	SAVE_REG(r19,   r0, 31)
+	SAVE_REG(r20,   r0, 30)
+	SAVE_REG(r21,   r0, 29)
+	SAVE_REG(r22,   r0, 28)
+	SAVE_REG(r23,   r0, 27)
+	SAVE_REG(r24,   r0, 26)
+	SAVE_REG(r25,   r0, 25)
+
+	SAVE_REG(blink, r0,  7)
+	SAVE_REG(fp,    r0,  8)
+	SAVE_REG(sp,    r0, 23)
+
+	/* save 0 in r0 placeholder to return 0 when @oucp activated */
+	mov r9, 0
+	SAVE_REG(r9,    r0, 22)
+
+	/* load context from @ucp */
+
+	mov r9, r1	; safekeep @ucp across syscall
+
+	/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask, _NSIG8) */
+	mov r3, _NSIG8
+	add r2, r0, UCONTEXT_SIGMASK
+	add r1, r1, UCONTEXT_SIGMASK
+	mov r0, SIG_SETMASK
+	mov r8, __NR_rt_sigprocmask
+	ARC_TRAP_INSN
+	brhi r0, -1024, .Lcall_syscall_err
+
+	LOAD_REG(r0,    r9, 22)
+	LOAD_REG(r1,    r9, 21)
+	LOAD_REG(r2,    r9, 20)
+	LOAD_REG(r3,    r9, 19)
+	LOAD_REG(r4,    r9, 18)
+	LOAD_REG(r5,    r9, 17)
+	LOAD_REG(r6,    r9, 16)
+	LOAD_REG(r7,    r9, 15)
+
+	LOAD_REG(r13,   r9, 37)
+	LOAD_REG(r14,   r9, 36)
+	LOAD_REG(r15,   r9, 35)
+	LOAD_REG(r16,   r9, 34)
+	LOAD_REG(r17,   r9, 33)
+	LOAD_REG(r18,   r9, 32)
+	LOAD_REG(r19,   r9, 31)
+	LOAD_REG(r20,   r9, 30)
+	LOAD_REG(r21,   r9, 29)
+	LOAD_REG(r22,   r9, 28)
+	LOAD_REG(r23,   r9, 27)
+	LOAD_REG(r24,   r9, 26)
+	LOAD_REG(r25,   r9, 25)
+
+	LOAD_REG(blink, r9,  7)
+	LOAD_REG(fp,    r9,  8)
+	LOAD_REG(sp,    r9, 23)
+
+	j    [blink]
+
+PSEUDO_END(__swapcontext)
+weak_alias(__swapcontext, swapcontext)
diff --git a/sysdeps/unix/sysv/linux/arc/sys/cachectl.h b/sysdeps/unix/sysv/linux/arc/sys/cachectl.h
new file mode 100644
index 000000000000..c2ba820e50b7
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sys/cachectl.h
@@ -0,0 +1,36 @@ 
+/* cacheflush - flush contents of instruction and/or data cache.
+   Copyright (C) 2017-2018 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 _SYS_CACHECTL_H
+#define _SYS_CACHECTL_H 1
+
+#include <features.h>
+
+/* Get the kernel definition for the op bits.  */
+#include <asm/cachectl.h>
+
+__BEGIN_DECLS
+
+#ifdef __USE_MISC
+extern int cacheflush (void *__addr, const int __nbytes, const int __op) __THROW;
+#endif
+extern int _flush_cache (char *__addr, const int __nbytes, const int __op) __THROW;
+
+__END_DECLS
+
+#endif /* sys/cachectl.h */
diff --git a/sysdeps/unix/sysv/linux/arc/sys/ucontext.h b/sysdeps/unix/sysv/linux/arc/sys/ucontext.h
new file mode 100644
index 000000000000..e91abc3d9fba
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sys/ucontext.h
@@ -0,0 +1,71 @@ 
+/* struct ucontext definition, ARC version.
+   Copyright (C) 2017-2018 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/>.  */
+
+/* System V/ARC ABI compliant context switching support.  */
+
+#ifndef _SYS_UCONTEXT_H
+#define _SYS_UCONTEXT_H	1
+
+#include <features.h>
+
+#include <bits/types/sigset_t.h>
+#include <bits/types/stack_t.h>
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
+typedef struct
+  {
+    unsigned long __ctx(pad);
+    struct {
+      unsigned long __ctx(bta);
+      unsigned long __ctx(lp_start), __ctx(lp_end), __ctx(lp_count);
+      unsigned long __ctx(status32), __ctx(ret), __ctx(blink);
+      unsigned long __ctx(fp), __ctx(gp);
+      unsigned long __ctx(r12), __ctx(r11), __ctx(r10), __ctx(r9), __ctx(r8);
+      unsigned long __ctx(r7), __ctx(r6), __ctx(r5), __ctx(r4), __ctx(r3);
+      unsigned long __ctx(r2), __ctx(r1), __ctx(r0);
+      unsigned long __ctx(sp);
+    } __ctx(scratch);
+    unsigned long __ctx(pad2);
+    struct {
+      unsigned long __ctx(r25), __ctx(r24), __ctx(r23), __ctx(r22), __ctx(r21);
+      unsigned long __ctx(r20), __ctx(r19), __ctx(r18), __ctx(r17), __ctx(r16);
+      unsigned long __ctx(r15), __ctx(r14), __ctx(r13);
+    } __ctx(callee);
+    unsigned long __ctx(efa);
+    unsigned long __ctx(stop_pc);
+    unsigned long __ctx(r30), __ctx(r58), __ctx(r59);
+  } mcontext_t;
+
+/* Userlevel context.  */
+typedef struct ucontext_t
+  {
+    unsigned long __ctx(uc_flags);
+    struct ucontext_t *uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    sigset_t uc_sigmask;
+  } ucontext_t;
+
+#undef __ctx
+
+#endif /* sys/ucontext.h */
diff --git a/sysdeps/unix/sysv/linux/arc/sys/user.h b/sysdeps/unix/sysv/linux/arc/sys/user.h
new file mode 100644
index 000000000000..1f7129799bf6
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sys/user.h
@@ -0,0 +1,32 @@ 
+/* ptrace register data format definitions.
+   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 _SYS_USER_H
+#define _SYS_USER_H	1
+
+/* struct user_regs_struct is exported by kernel header
+ * However apps like strace also expect a struct user, so it's better to
+ * have a dummy implementation
+ */
+#include <asm/ptrace.h>
+
+struct user {
+	int dummy;
+};
+
+#endif  /* sys/user.h */
diff --git a/sysdeps/unix/sysv/linux/arc/ucontext-macros.h b/sysdeps/unix/sysv/linux/arc/ucontext-macros.h
new file mode 100644
index 000000000000..a5d861476f3c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/ucontext-macros.h
@@ -0,0 +1,29 @@ 
+/* Macros for ucontext routines - ARC
+   Copyright (C) 2017-2018 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 _LINUX_ARC_UCONTEXT_MACROS_H
+#define _LINUX_ARC_UCONTEXT_MACROS_H
+
+#include <sysdep.h>
+
+#include "ucontext_i.h"
+
+#define SAVE_REG(reg, rbase, off)	st  reg, [rbase, UCONTEXT_MCONTEXT + off * 4]
+#define LOAD_REG(reg, rbase, off)	ld  reg, [rbase, UCONTEXT_MCONTEXT + off * 4]
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/arc/ucontext_i.sym b/sysdeps/unix/sysv/linux/arc/ucontext_i.sym
new file mode 100644
index 000000000000..f0a209e581ab
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/ucontext_i.sym
@@ -0,0 +1,20 @@ 
+#include <inttypes.h>
+#include <signal.h>
+#include <stddef.h>
+#include <sys/ucontext.h>
+
+SIG_BLOCK
+SIG_SETMASK
+
+-- sizeof(sigset_t) expected by kernel: see comment in ARC sigaction.c for details
+_NSIG8				(_NSIG / 8)
+
+-- Offsets of the fields in the ucontext_t structure.
+#define ucontext(member)	offsetof (ucontext_t, member)
+
+UCONTEXT_FLAGS			ucontext (uc_flags)
+UCONTEXT_LINK			ucontext (uc_link)
+UCONTEXT_STACK			ucontext (uc_stack)
+UCONTEXT_MCONTEXT		ucontext (uc_mcontext)
+UCONTEXT_SIGMASK		ucontext (uc_sigmask)
+UCONTEXT_SIZE			sizeof (ucontext_t)