[v7.1,07/13] ARC: Linux Syscall Interface

Message ID 20200701000848.20492-1-vgupta@synopsys.com
State Superseded
Headers show
Series
  • Untitled series #27399
Related show

Commit Message

Alistair Francis via Libc-alpha July 1, 2020, 12:08 a.m.
---
   Changes since v7:
     - used long int (iso int) in sysdep.h/syscall_error for handling registers
---
 sysdeps/unix/sysv/linux/arc/arch-syscall.h    | 303 ++++++++++++++++++
 sysdeps/unix/sysv/linux/arc/bits/timesize.h   |  21 ++
 sysdeps/unix/sysv/linux/arc/clone.S           |  93 ++++++
 .../unix/sysv/linux/arc/fixup-asm-unistd.h    |  41 +++
 sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h  |   6 +
 sysdeps/unix/sysv/linux/arc/kernel-features.h |  27 ++
 sysdeps/unix/sysv/linux/arc/kernel_stat.h     |  26 ++
 sysdeps/unix/sysv/linux/arc/mmap_internal.h   |  27 ++
 sysdeps/unix/sysv/linux/arc/sigaction.c       |  31 ++
 sysdeps/unix/sysv/linux/arc/sigrestorer.S     |  29 ++
 sysdeps/unix/sysv/linux/arc/syscall.S         |  33 ++
 sysdeps/unix/sysv/linux/arc/syscalls.list     |   3 +
 sysdeps/unix/sysv/linux/arc/sysdep.c          |  33 ++
 sysdeps/unix/sysv/linux/arc/sysdep.h          | 224 +++++++++++++
 sysdeps/unix/sysv/linux/arc/vfork.S           |  42 +++
 15 files changed, 939 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/arc/arch-syscall.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/bits/timesize.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/clone.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/kernel-features.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/kernel_stat.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/mmap_internal.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/sigaction.c
 create mode 100644 sysdeps/unix/sysv/linux/arc/sigrestorer.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/syscall.S
 create mode 100644 sysdeps/unix/sysv/linux/arc/syscalls.list
 create mode 100644 sysdeps/unix/sysv/linux/arc/sysdep.c
 create mode 100644 sysdeps/unix/sysv/linux/arc/sysdep.h
 create mode 100644 sysdeps/unix/sysv/linux/arc/vfork.S

-- 
2.20.1

Comments

Alistair Francis via Libc-alpha July 3, 2020, 2:47 a.m. | #1
On 30/06/2020 21:08, Vineet Gupta via Libc-alpha wrote:
> ---

>    Changes since v7:

>      - used long int (iso int) in sysdep.h/syscall_error for handling registers


Patch looks ok, but I have question on the __NR_* undef/define. 

> ---

>  sysdeps/unix/sysv/linux/arc/arch-syscall.h    | 303 ++++++++++++++++++

>  sysdeps/unix/sysv/linux/arc/bits/timesize.h   |  21 ++

>  sysdeps/unix/sysv/linux/arc/clone.S           |  93 ++++++

>  .../unix/sysv/linux/arc/fixup-asm-unistd.h    |  41 +++

>  sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h  |   6 +

>  sysdeps/unix/sysv/linux/arc/kernel-features.h |  27 ++

>  sysdeps/unix/sysv/linux/arc/kernel_stat.h     |  26 ++

>  sysdeps/unix/sysv/linux/arc/mmap_internal.h   |  27 ++

>  sysdeps/unix/sysv/linux/arc/sigaction.c       |  31 ++

>  sysdeps/unix/sysv/linux/arc/sigrestorer.S     |  29 ++

>  sysdeps/unix/sysv/linux/arc/syscall.S         |  33 ++

>  sysdeps/unix/sysv/linux/arc/syscalls.list     |   3 +

>  sysdeps/unix/sysv/linux/arc/sysdep.c          |  33 ++

>  sysdeps/unix/sysv/linux/arc/sysdep.h          | 224 +++++++++++++

>  sysdeps/unix/sysv/linux/arc/vfork.S           |  42 +++

>  15 files changed, 939 insertions(+)

>  create mode 100644 sysdeps/unix/sysv/linux/arc/arch-syscall.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/bits/timesize.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/clone.S

>  create mode 100644 sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/kernel-features.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/kernel_stat.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/mmap_internal.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/sigaction.c

>  create mode 100644 sysdeps/unix/sysv/linux/arc/sigrestorer.S

>  create mode 100644 sysdeps/unix/sysv/linux/arc/syscall.S

>  create mode 100644 sysdeps/unix/sysv/linux/arc/syscalls.list

>  create mode 100644 sysdeps/unix/sysv/linux/arc/sysdep.c

>  create mode 100644 sysdeps/unix/sysv/linux/arc/sysdep.h

>  create mode 100644 sysdeps/unix/sysv/linux/arc/vfork.S

> 

> diff --git a/sysdeps/unix/sysv/linux/arc/arch-syscall.h b/sysdeps/unix/sysv/linux/arc/arch-syscall.h

> new file mode 100644

> index 000000000000..2b017eb5bbaa

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/arch-syscall.h

> @@ -0,0 +1,303 @@

> +/* AUTOGENERATED by update-syscall-lists.py.  */

> +#define __NR_accept 202

> +#define __NR_accept4 242

> +#define __NR_acct 89

> +#define __NR_add_key 217

> +#define __NR_adjtimex 171

> +#define __NR_arc_gettls 246

> +#define __NR_arc_settls 245

> +#define __NR_arc_usr_cmpxchg 248

> +#define __NR_bind 200

> +#define __NR_bpf 280

> +#define __NR_brk 214

> +#define __NR_cacheflush 244

> +#define __NR_capget 90

> +#define __NR_capset 91

> +#define __NR_chdir 49

> +#define __NR_chroot 51

> +#define __NR_clock_adjtime64 405

> +#define __NR_clock_getres_time64 406

> +#define __NR_clock_gettime 113

> +#define __NR_clock_gettime64 403

> +#define __NR_clock_nanosleep 115

> +#define __NR_clock_nanosleep_time64 407

> +#define __NR_clock_settime 112

> +#define __NR_clock_settime64 404

> +#define __NR_clone 220

> +#define __NR_clone3 435

> +#define __NR_close 57

> +#define __NR_connect 203

> +#define __NR_copy_file_range 285

> +#define __NR_delete_module 106

> +#define __NR_dup 23

> +#define __NR_dup3 24

> +#define __NR_epoll_create1 20

> +#define __NR_epoll_ctl 21

> +#define __NR_epoll_pwait 22

> +#define __NR_eventfd2 19

> +#define __NR_execve 221

> +#define __NR_execveat 281

> +#define __NR_exit 93

> +#define __NR_exit_group 94

> +#define __NR_faccessat 48

> +#define __NR_fadvise64_64 223

> +#define __NR_fallocate 47

> +#define __NR_fanotify_init 262

> +#define __NR_fanotify_mark 263

> +#define __NR_fchdir 50

> +#define __NR_fchmod 52

> +#define __NR_fchmodat 53

> +#define __NR_fchown 55

> +#define __NR_fchownat 54

> +#define __NR_fcntl64 25

> +#define __NR_fdatasync 83

> +#define __NR_fgetxattr 10

> +#define __NR_finit_module 273

> +#define __NR_flistxattr 13

> +#define __NR_flock 32

> +#define __NR_fremovexattr 16

> +#define __NR_fsconfig 431

> +#define __NR_fsetxattr 7

> +#define __NR_fsmount 432

> +#define __NR_fsopen 430

> +#define __NR_fspick 433

> +#define __NR_fstatfs64 44

> +#define __NR_fsync 82

> +#define __NR_ftruncate64 46

> +#define __NR_futex_time64 422

> +#define __NR_get_mempolicy 236

> +#define __NR_get_robust_list 100

> +#define __NR_getcpu 168

> +#define __NR_getcwd 17

> +#define __NR_getdents64 61

> +#define __NR_getegid 177

> +#define __NR_geteuid 175

> +#define __NR_getgid 176

> +#define __NR_getgroups 158

> +#define __NR_getitimer 102

> +#define __NR_getpeername 205

> +#define __NR_getpgid 155

> +#define __NR_getpid 172

> +#define __NR_getppid 173

> +#define __NR_getpriority 141

> +#define __NR_getrandom 278

> +#define __NR_getresgid 150

> +#define __NR_getresuid 148

> +#define __NR_getrlimit 163

> +#define __NR_getrusage 165

> +#define __NR_getsid 156

> +#define __NR_getsockname 204

> +#define __NR_getsockopt 209

> +#define __NR_gettid 178

> +#define __NR_gettimeofday 169

> +#define __NR_getuid 174

> +#define __NR_getxattr 8

> +#define __NR_init_module 105

> +#define __NR_inotify_add_watch 27

> +#define __NR_inotify_init1 26

> +#define __NR_inotify_rm_watch 28

> +#define __NR_io_cancel 3

> +#define __NR_io_destroy 1

> +#define __NR_io_getevents 4

> +#define __NR_io_pgetevents 292

> +#define __NR_io_pgetevents_time64 416

> +#define __NR_io_setup 0

> +#define __NR_io_submit 2

> +#define __NR_io_uring_enter 426

> +#define __NR_io_uring_register 427

> +#define __NR_io_uring_setup 425

> +#define __NR_ioctl 29

> +#define __NR_ioprio_get 31

> +#define __NR_ioprio_set 30

> +#define __NR_kcmp 272

> +#define __NR_kexec_file_load 294

> +#define __NR_kexec_load 104

> +#define __NR_keyctl 219

> +#define __NR_kill 129

> +#define __NR_lgetxattr 9

> +#define __NR_linkat 37

> +#define __NR_listen 201

> +#define __NR_listxattr 11

> +#define __NR_llistxattr 12

> +#define __NR_llseek 62

> +#define __NR_lookup_dcookie 18

> +#define __NR_lremovexattr 15

> +#define __NR_lsetxattr 6

> +#define __NR_madvise 233

> +#define __NR_mbind 235

> +#define __NR_membarrier 283

> +#define __NR_memfd_create 279

> +#define __NR_migrate_pages 238

> +#define __NR_mincore 232

> +#define __NR_mkdirat 34

> +#define __NR_mknodat 33

> +#define __NR_mlock 228

> +#define __NR_mlock2 284

> +#define __NR_mlockall 230

> +#define __NR_mmap2 222

> +#define __NR_mount 40

> +#define __NR_move_mount 429

> +#define __NR_move_pages 239

> +#define __NR_mprotect 226

> +#define __NR_mq_getsetattr 185

> +#define __NR_mq_notify 184

> +#define __NR_mq_open 180

> +#define __NR_mq_timedreceive_time64 419

> +#define __NR_mq_timedsend_time64 418

> +#define __NR_mq_unlink 181

> +#define __NR_mremap 216

> +#define __NR_msgctl 187

> +#define __NR_msgget 186

> +#define __NR_msgrcv 188

> +#define __NR_msgsnd 189

> +#define __NR_msync 227

> +#define __NR_munlock 229

> +#define __NR_munlockall 231

> +#define __NR_munmap 215

> +#define __NR_name_to_handle_at 264

> +#define __NR_nanosleep 101

> +#define __NR_nfsservctl 42

> +#define __NR_open_by_handle_at 265

> +#define __NR_open_tree 428

> +#define __NR_openat 56

> +#define __NR_openat2 437

> +#define __NR_perf_event_open 241

> +#define __NR_personality 92

> +#define __NR_pidfd_getfd 438

> +#define __NR_pidfd_open 434

> +#define __NR_pidfd_send_signal 424

> +#define __NR_pipe2 59

> +#define __NR_pivot_root 41

> +#define __NR_pkey_alloc 289

> +#define __NR_pkey_free 290

> +#define __NR_pkey_mprotect 288

> +#define __NR_ppoll_time64 414

> +#define __NR_prctl 167

> +#define __NR_pread64 67

> +#define __NR_preadv 69

> +#define __NR_preadv2 286

> +#define __NR_prlimit64 261

> +#define __NR_process_vm_readv 270

> +#define __NR_process_vm_writev 271

> +#define __NR_pselect6_time64 413

> +#define __NR_ptrace 117

> +#define __NR_pwrite64 68

> +#define __NR_pwritev 70

> +#define __NR_pwritev2 287

> +#define __NR_quotactl 60

> +#define __NR_read 63

> +#define __NR_readahead 213

> +#define __NR_readlinkat 78

> +#define __NR_readv 65

> +#define __NR_reboot 142

> +#define __NR_recvfrom 207

> +#define __NR_recvmmsg_time64 417

> +#define __NR_recvmsg 212

> +#define __NR_remap_file_pages 234

> +#define __NR_removexattr 14

> +#define __NR_renameat 38

> +#define __NR_renameat2 276

> +#define __NR_request_key 218

> +#define __NR_restart_syscall 128

> +#define __NR_rseq 293

> +#define __NR_rt_sigaction 134

> +#define __NR_rt_sigpending 136

> +#define __NR_rt_sigprocmask 135

> +#define __NR_rt_sigqueueinfo 138

> +#define __NR_rt_sigreturn 139

> +#define __NR_rt_sigsuspend 133

> +#define __NR_rt_sigtimedwait_time64 421

> +#define __NR_rt_tgsigqueueinfo 240

> +#define __NR_sched_get_priority_max 125

> +#define __NR_sched_get_priority_min 126

> +#define __NR_sched_getaffinity 123

> +#define __NR_sched_getattr 275

> +#define __NR_sched_getparam 121

> +#define __NR_sched_getscheduler 120

> +#define __NR_sched_rr_get_interval_time64 423

> +#define __NR_sched_setaffinity 122

> +#define __NR_sched_setattr 274

> +#define __NR_sched_setparam 118

> +#define __NR_sched_setscheduler 119

> +#define __NR_sched_yield 124

> +#define __NR_seccomp 277

> +#define __NR_semctl 191

> +#define __NR_semget 190

> +#define __NR_semop 193

> +#define __NR_semtimedop_time64 420

> +#define __NR_sendfile64 71

> +#define __NR_sendmmsg 269

> +#define __NR_sendmsg 211

> +#define __NR_sendto 206

> +#define __NR_set_mempolicy 237

> +#define __NR_set_robust_list 99

> +#define __NR_set_tid_address 96

> +#define __NR_setdomainname 162

> +#define __NR_setfsgid 152

> +#define __NR_setfsuid 151

> +#define __NR_setgid 144

> +#define __NR_setgroups 159

> +#define __NR_sethostname 161

> +#define __NR_setitimer 103

> +#define __NR_setns 268

> +#define __NR_setpgid 154

> +#define __NR_setpriority 140

> +#define __NR_setregid 143

> +#define __NR_setresgid 149

> +#define __NR_setresuid 147

> +#define __NR_setreuid 145

> +#define __NR_setrlimit 164

> +#define __NR_setsid 157

> +#define __NR_setsockopt 208

> +#define __NR_settimeofday 170

> +#define __NR_setuid 146

> +#define __NR_setxattr 5

> +#define __NR_shmat 196

> +#define __NR_shmctl 195

> +#define __NR_shmdt 197

> +#define __NR_shmget 194

> +#define __NR_shutdown 210

> +#define __NR_sigaltstack 132

> +#define __NR_signalfd4 74

> +#define __NR_socket 198

> +#define __NR_socketpair 199

> +#define __NR_splice 76

> +#define __NR_statfs64 43

> +#define __NR_statx 291

> +#define __NR_swapoff 225

> +#define __NR_swapon 224

> +#define __NR_symlinkat 36

> +#define __NR_sync 81

> +#define __NR_sync_file_range 84

> +#define __NR_syncfs 267

> +#define __NR_sysfs 247

> +#define __NR_sysinfo 179

> +#define __NR_syslog 116

> +#define __NR_tee 77

> +#define __NR_tgkill 131

> +#define __NR_timer_create 107

> +#define __NR_timer_delete 111

> +#define __NR_timer_getoverrun 109

> +#define __NR_timer_gettime 108

> +#define __NR_timer_gettime64 408

> +#define __NR_timer_settime 110

> +#define __NR_timer_settime64 409

> +#define __NR_timerfd_create 85

> +#define __NR_timerfd_gettime64 410

> +#define __NR_timerfd_settime64 411

> +#define __NR_times 153

> +#define __NR_tkill 130

> +#define __NR_truncate64 45

> +#define __NR_umask 166

> +#define __NR_umount2 39

> +#define __NR_uname 160

> +#define __NR_unlinkat 35

> +#define __NR_unshare 97

> +#define __NR_userfaultfd 282

> +#define __NR_utimensat_time64 412

> +#define __NR_vhangup 58

> +#define __NR_vmsplice 75

> +#define __NR_wait4 260

> +#define __NR_waitid 95

> +#define __NR_write 64

> +#define __NR_writev 66


Looks good. As side note I think an improvement would be to add
an annotation on update-syscall-lists.py to specify which kernel
version it used.

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

> new file mode 100644

> index 000000000000..bf44f09f7619

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/bits/timesize.h

> @@ -0,0 +1,21 @@

> +/* Bit size of the time_t type at glibc build time, general case.

> +   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

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

> +

> +#include <bits/wordsize.h>

> +

> +#define __TIMESIZE	64


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

> new file mode 100644

> index 000000000000..035b285ff98f

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/clone.S

> @@ -0,0 +1,93 @@

> +/* clone() implementation for ARC.

> +   Copyright (C) 2020 Free Software Foundation, Inc.

> +   This file is part of the GNU C Library.

> +   Contributed by Andrew Jenner <andrew@codesourcery.com>, 2008.

> +

> +   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 <sysdep.h>

> +#define _ERRNO_H	1

> +#include <bits/errno.h>

> +#include <tcb-offsets.h>

> +

> +#define CLONE_SETTLS		0x00080000

> +

> +/* int clone(int (*fn)(void *), void *child_stack,

> +           int flags, void *arg, ...

> +           < pid_t *ptid, struct user_desc *tls, pid_t *ctid > );

> +

> + NOTE: I'm assuming that the last 3 args are NOT var-args and in case all

> +	3 are not relevant, caller will nevertheless pass those as NULL.

> +

> + clone syscall in kernel (ABI: CONFIG_CLONE_BACKWARDS)

> +

> +  int sys_clone(unsigned long int clone_flags,

> +	        unsigned long int newsp,

> +		int __user *parent_tidptr,

> +		void *tls,

> +		int __user *child_tidptr).  */

> +

> +ENTRY (__clone)

> +	cmp	r0, 0		/* @fn can't be NULL.  */

> +	cmp.ne	r1, 0		/* @child_stack can't be NULL.  */

> +	bz	L (__sys_err)

> +

> +	/* save some of the orig args

> +	   r0 containg @fn will be clobbered AFTER syscall (with ret val)

> +	   rest are clobbered BEFORE syscall due to different arg ordering.  */

> +	mov	r10, r0		/* @fn.  */

> +	mov	r11, r3		/* @args.  */

> +	mov	r12, r2		/* @clone_flags.  */

> +	mov	r9,  r5		/* @tls.  */

> +

> +	; adjust libc args for syscall


Use the C comment style for constency with rest of the file.

> +

> +	mov 	r0, r2		/* libc @flags is 1st syscall arg.  */

> +	mov	r2, r4		/* libc @ptid.  */

> +	mov	r3, r5		/* libc @tls.  */

> +	mov	r4, r6		/* libc @ctid.  */

> +	mov	r8, __NR_clone

> +	ARC_TRAP_INSN

> +

> +	cmp	r0, 0		/* return code : 0 new process, !0 parent.  */

> +	blt	L (__sys_err2)	/* < 0 (signed) error.  */

> +	jnz	[blink]		/* Parent returns.  */

> +

> +	/* child jumps off to @fn with @arg as argument

> +           TP register already set by kernel.  */

> +	jl.d	[r10]

> +	mov	r0, r11

> +

> +	/* exit() with result from @fn (already in r0).  */

> +	mov	r8, __NR_exit

> +	ARC_TRAP_INSN

> +	/* In case it ever came back.  */

> +	flag	1

> +

> +L (__sys_err):

> +	mov	r0, -EINVAL

> +L (__sys_err2):

> +	/* (1) No need to make -ve kernel error code as positive errno

> +	       __syscall_error expects the -ve error code returned by kernel

> +	   (2) r0 still had orig -ve kernel error code

> +	   (3) Tail call to __syscall_error so we dont have to come back

> +	       here hence instead of jmp-n-link (reg push/pop) we do jmp

> +	   (4) No need to route __syscall_error via PLT, B is inherently

> +	       position independent.  */

> +	b   __syscall_error

> +PSEUDO_END (__clone)

> +libc_hidden_def (__clone)

> +weak_alias (__clone, clone)


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

> new file mode 100644

> index 000000000000..47faaecc8970

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

> @@ -0,0 +1,41 @@

> +/* Regularize <asm/unistd.h> definitions.  ARC version.

> +   Copyright (C) 2020 Free Software Foundation, Inc.

> +

> +   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/>.  */

> +

> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

> +   support.  */

> +

> +/* fstat64 and fstatat64 need to be replaced with statx.  */

> +

> +#undef __NR_fstat64

> +#undef __NR_fstatat64

> +

> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

> +

> +# undef __NR_clock_adjtime

> +# undef __NR_clock_getres

> +# undef __NR_futex

> +# undef __NR_mq_timedreceive

> +# undef __NR_mq_timedsend

> +# undef __NR_ppoll

> +# undef __NR_pselect6

> +# undef __NR_recvmmsg

> +# undef __NR_rt_sigtimedwait

> +# undef __NR_sched_rr_get_interval

> +# undef __NR_semtimedop

> +# undef __NR_timerfd_settime

> +# undef __NR_timerfd_gettime

> +# undef __NR_utimensat


I am trying to understand why these are required since arc does not define 
them in arch-syscall.h.

And the generic implementation should handle the time64 variant.  If they
are not this is something we need to handle it.

> diff --git a/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h b/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h

> new file mode 100644

> index 000000000000..296f3197ee31

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h

> @@ -0,0 +1,6 @@

> +#define JMP_BUF_SIZE		(32 + 1 + 64 / (8 * sizeof (unsigned long int))) * sizeof (unsigned long int)

> +#define SIGJMP_BUF_SIZE		(32 + 1 + 64 / (8 * sizeof (unsigned long int))) * sizeof (unsigned long int)

> +#define JMP_BUF_ALIGN		__alignof__ (unsigned long int)

> +#define SIGJMP_BUF_ALIGN	__alignof__ (unsigned long int)

> +#define MASK_WAS_SAVED_OFFSET	(32 * sizeof (unsigned long int))

> +#define SAVED_MASK_OFFSET	(33 * sizeof (unsigned long int))


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/kernel-features.h b/sysdeps/unix/sysv/linux/arc/kernel-features.h

> new file mode 100644

> index 000000000000..0a5c9e21fbf2

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/kernel-features.h

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

> +/* Set flags signalling availability of kernel features based on given

> +   kernel version number.

> +

> +   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/>.  */

> +

> +/* The minimum supported kernel version for ARC is 5.1 (64-bit time, offsets),

> +   although the asm-generic ABI is from 3.9 (when Linux port was merged).  */

> +

> +#include_next <kernel-features.h>

> +

> +#undef __ASSUME_CLONE_DEFAULT

> +#define __ASSUME_CLONE_BACKWARDS 1


Ok.

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

> new file mode 100644

> index 000000000000..8fdd86b9e843

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/kernel_stat.h

> @@ -0,0 +1,26 @@

> +/* 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 <bits/wordsize.h>

> +

> +/* Needed to elide the itemized copy code in common xstatconv.c.  */

> +#define STAT_IS_KERNEL_STAT 1

> +

> +/* Nice side-effect of 64-bit time_t switch is these are same.  */

> +#define XSTAT_IS_XSTAT64 1

> +

> +#define STATFS_IS_STATFS64 0


Ok.

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

> new file mode 100644

> index 000000000000..5293d670adaa

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/mmap_internal.h

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

> +/* mmap - map files or devices into memory.  Linux/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 MMAP_ARC_INTERNAL_H

> +#define MMAP_ARC_INTERNAL_H

> +

> +/* 8K is default but determine the shift dynamically with getpagesize.  */

> +#define MMAP2_PAGE_UNIT -1

> +

> +#include_next <mmap_internal.h>

> +

> +#endif


Ok.

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

> new file mode 100644

> index 000000000000..dd590ecb6dd7

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/sigaction.c

> @@ -0,0 +1,31 @@

> +/* ARC specific sigaction.

> +   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/>.  */

> +

> +#define SA_RESTORER	0x04000000

> +

> +extern void __default_rt_sa_restorer (void);

> +

> +#define SET_SA_RESTORER(kact, act)				\

> + ({								\

> +   (kact)->sa_restorer = __default_rt_sa_restorer;		\

> +   (kact)->sa_flags |= SA_RESTORER;				\

> + })

> +

> +#define RESET_SA_RESTORER(act, kact)

> +

> +#include <sysdeps/unix/sysv/linux/sigaction.c>


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/sigrestorer.S b/sysdeps/unix/sysv/linux/arc/sigrestorer.S

> new file mode 100644

> index 000000000000..eaabef505ec2

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/sigrestorer.S

> @@ -0,0 +1,29 @@

> +/* Default sigreturn stub for ARC Linux.

> +   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 <sys/syscall.h>

> +#include <sysdep.h>

> +#include <tcb-offsets.h>

> +

> +/* Note the NOP has to be outside body.  */

> +	nop

> +ENTRY (__default_rt_sa_restorer)

> +	mov r8, __NR_rt_sigreturn

> +	ARC_TRAP_INSN

> +	j_s     [blink]

> +PSEUDO_END_NOERRNO (__default_rt_sa_restorer)


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/syscall.S b/sysdeps/unix/sysv/linux/arc/syscall.S

> new file mode 100644

> index 000000000000..6227dbf49917

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/syscall.S

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

> +/* syscall - indirect system call.

> +   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 <sysdep.h>

> +

> +ENTRY (syscall)

> +	mov_s	r8, r0

> +	mov_s	r0, r1

> +	mov_s	r1, r2

> +	mov_s	r2, r3

> +	mov_s	r3, r4

> +	mov_s	r4, r5

> +	mov_s	r5, r6

> +

> +	ARC_TRAP_INSN

> +	brhi	r0, -4096, L (call_syscall_err)

> +	j	[blink]

> +PSEUDO_END (syscall)


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/syscalls.list b/sysdeps/unix/sysv/linux/arc/syscalls.list

> new file mode 100644

> index 000000000000..d0ef5977ee06

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/syscalls.list

> @@ -0,0 +1,3 @@

> +# File name	Caller	Syscall name	Args	Strong name	Weak names

> +

> +cacheflush	-	cacheflush	i:pii	_flush_cache	cacheflush


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/sysdep.c b/sysdeps/unix/sysv/linux/arc/sysdep.c

> new file mode 100644

> index 000000000000..f33d64679886

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/sysdep.c

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

> +/* ARC wrapper for setting errno.

> +   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 <sysdep.h>

> +#include <errno.h>

> +

> +/* All syscall handlers land here to avoid generated code bloat due to

> +   GOT reference  to errno_location or it's equivalent.  */

> +long int

> +__syscall_error (long int err_no)

> +{

> +  __set_errno (-err_no);

> +  return -1;

> +}

> +

> +#if IS_IN (libc)

> +hidden_def (__syscall_error)

> +#endif


Ok.

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

> new file mode 100644

> index 000000000000..54d7ede75600

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/sysdep.h

> @@ -0,0 +1,224 @@

> +/* Assembler macros 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/>.  */

> +

> +#ifndef _LINUX_ARC_SYSDEP_H

> +#define _LINUX_ARC_SYSDEP_H 1

> +

> +#include <sysdeps/arc/sysdep.h>

> +#include <sysdeps/unix/sysv/linux/generic/sysdep.h>

> +

> +/* 32-bit time syscalls are not available, but the redefines allow generic

> +   wrappers to work.  */

> +#define __NR_clock_adjtime	__NR_clock_adjtime64

> +#define __NR_clock_getres	__NR_clock_getres_time64

> +#define __NR_futex		__NR_futex_time64

> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

> +#define __NR_ppoll		__NR_ppoll_time64

> +#define __NR_pselect6		__NR_pselect6_time64

> +#define __NR_recvmmsg		__NR_recvmmsg_time64

> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

> +#define __NR_semtimedop		__NR_semtimedop_time64

> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

> +#define __NR_timerfd_settime	__NR_timerfd_settime64

> +#define __NR_utimensat		__NR_utimensat_time64


As for the fixup-asm-unistd.h, the generic implementation should handle it
without the requirement of the ABI to add such tricks.

However it seems that we are still missing support for pselect 
(__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 
(__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

I think we can add the redefine hack only the aforementioned symbols for
now and removed them once we implement the y2038 support on such symbols
(since the expected ABI won't change for ARC, only for old ABIs with
32 time_t support).

> +

> +/* For RTLD_PRIVATE_ERRNO.  */

> +#include <dl-sysdep.h>

> +

> +#include <tls.h>

> +

> +#undef SYS_ify

> +#define SYS_ify(syscall_name)   __NR_##syscall_name


The code mixes __NR_* and SYS_ify macro. This macro is really superflous
and I am preparing some patches to cleanup this up along with C asm
macros to generate syscall.  So I would suggest to just use the __NR_*
way and drop this definition.

> +

> +#ifdef __ASSEMBLER__

> +

> +/* This is a "normal" system call stub: if there is an error,

> +   it returns -1 and sets errno.  */

> +

> +# undef PSEUDO

> +# define PSEUDO(name, syscall_name, args)			\

> +  PSEUDO_NOERRNO(name, syscall_name, args)	ASM_LINE_SEP	\

> +    brhi   r0, -4096, L (call_syscall_err)	ASM_LINE_SEP

> +

> +# define ret	j_s  [blink]

> +

> +# undef PSEUDO_END

> +# define PSEUDO_END(name)					\

> +  SYSCALL_ERROR_HANDLER				ASM_LINE_SEP	\

> +  END (name)

> +

> +/* --------- Helper for SYSCALL_NOERRNO -----------

> +   This kind of system call stub never returns an error.

> +   We return the return value register to the caller unexamined.  */

> +

> +# undef PSEUDO_NOERRNO

> +# define PSEUDO_NOERRNO(name, syscall_name, args)		\

> +  .text						ASM_LINE_SEP	\

> +  ENTRY (name)					ASM_LINE_SEP	\

> +    DO_CALL (syscall_name, args)		ASM_LINE_SEP	\

> +

> +/* Return the return value register unexamined. Since r0 is both

> +   syscall return reg and function return reg, no work needed.  */

> +# define ret_NOERRNO						\

> +  j_s  [blink]		ASM_LINE_SEP

> +

> +# undef PSEUDO_END_NOERRNO

> +# define PSEUDO_END_NOERRNO(name)				\

> +  END (name)

> +

> +/* --------- Helper for SYSCALL_ERRVAL -----------

> +   This kind of system call stub returns the errno code as its return

> +   value, or zero for success.  We may massage the kernel's return value

> +   to meet that ABI, but we never set errno here.  */

> +

> +# undef PSEUDO_ERRVAL

> +# define PSEUDO_ERRVAL(name, syscall_name, args)		\

> +  PSEUDO_NOERRNO(name, syscall_name, args)	ASM_LINE_SEP

> +

> +/* Don't set errno, return kernel error (in errno form) or zero.  */

> +# define ret_ERRVAL						\

> +  rsub   r0, r0, 0				ASM_LINE_SEP	\

> +  ret_NOERRNO

> +

> +# undef PSEUDO_END_ERRVAL

> +# define PSEUDO_END_ERRVAL(name)				\

> +  END (name)

> +

> +

> +/* To reduce the code footprint, we confine the actual errno access

> +   to single place in __syscall_error().

> +   This takes raw kernel error value, sets errno and returns -1.  */

> +# if IS_IN (libc)

> +#  define CALL_ERRNO_SETTER_C	bl     PLTJMP(HIDDEN_JUMPTARGET(__syscall_error))

> +# else

> +#  define CALL_ERRNO_SETTER_C	bl     PLTJMP(__syscall_error)

> +# endif

> +

> +# define SYSCALL_ERROR_HANDLER				\

> +L (call_syscall_err):			ASM_LINE_SEP	\

> +    push_s   blink			ASM_LINE_SEP	\

> +    cfi_adjust_cfa_offset (4)		ASM_LINE_SEP	\

> +    cfi_rel_offset (blink, 0)		ASM_LINE_SEP	\

> +    CALL_ERRNO_SETTER_C			ASM_LINE_SEP	\

> +    pop_s  blink			ASM_LINE_SEP	\

> +    cfi_adjust_cfa_offset (-4)		ASM_LINE_SEP	\

> +    cfi_restore (blink)			ASM_LINE_SEP	\

> +    j_s      [blink]

> +

> +# define DO_CALL(syscall_name, args)				\

> +    mov    r8, SYS_ify (syscall_name)	ASM_LINE_SEP	\

> +    ARC_TRAP_INSN			ASM_LINE_SEP

> +

> +# define ARC_TRAP_INSN	trap_s 0

> +

> +#else  /* !__ASSEMBLER__ */

> +

> +# define SINGLE_THREAD_BY_GLOBAL		1

> +

> +# if IS_IN (libc)

> +extern long int __syscall_error (long int);

> +hidden_proto (__syscall_error)

> +# endif

> +

> +# define ARC_TRAP_INSN	"trap_s 0	\n\t"

> +

> +# undef INTERNAL_SYSCALL_NCS

> +# define INTERNAL_SYSCALL_NCS(number, nr_args, args...)	\

> +  ({								\

> +    /* Per ABI, r0 is 1st arg and return reg.  */		\

> +    register long int __ret __asm__("r0");			\

> +    register long int _sys_num __asm__("r8");			\

> +								\

> +    LOAD_ARGS_##nr_args (number, args)				\

> +								\

> +    __asm__ volatile (						\

> +                      ARC_TRAP_INSN				\

> +                      : "+r" (__ret)				\

> +                      : "r"(_sys_num) ASM_ARGS_##nr_args	\

> +                      : "memory");				\

> +                                                                \

> +    __ret; })

> +

> +# undef INTERNAL_SYSCALL

> +# define INTERNAL_SYSCALL(name, nr, args...) 	\

> +  INTERNAL_SYSCALL_NCS(SYS_ify(name), nr, args)

> +

> +/* Macros for setting up inline __asm__ input regs.  */

> +# define ASM_ARGS_0

> +# define ASM_ARGS_1	ASM_ARGS_0, "r" (__ret)

> +# define ASM_ARGS_2	ASM_ARGS_1, "r" (_arg2)

> +# define ASM_ARGS_3	ASM_ARGS_2, "r" (_arg3)

> +# define ASM_ARGS_4	ASM_ARGS_3, "r" (_arg4)

> +# define ASM_ARGS_5	ASM_ARGS_4, "r" (_arg5)

> +# define ASM_ARGS_6	ASM_ARGS_5, "r" (_arg6)

> +# define ASM_ARGS_7	ASM_ARGS_6, "r" (_arg7)

> +

> +/* Macros for converting sys-call wrapper args into sys call args.  */

> +# define LOAD_ARGS_0(nm, arg)				\

> +  _sys_num = (long int) (nm);

> +

> +# define LOAD_ARGS_1(nm, arg1)				\

> +  __ret = (long int) (arg1);					\

> +  LOAD_ARGS_0 (nm, arg1)

> +

> +/* Note that the use of _tmpX might look superflous, however it is needed

> +   to ensure that register variables are not clobbered if arg happens to be

> +   a function call itself. e.g. sched_setaffinity() calling getpid() for arg2

> +   Also this specific order of recursive calling is important to segregate

> +   the tmp args evaluation (function call case described above) and assigment

> +   of register variables.  */

> +

> +# define LOAD_ARGS_2(nm, arg1, arg2)			\

> +  long int _tmp2 = (long int) (arg2);			\

> +  LOAD_ARGS_1 (nm, arg1)				\

> +  register long int _arg2 __asm__ ("r1") = _tmp2;

> +

> +# define LOAD_ARGS_3(nm, arg1, arg2, arg3)		\

> +  long int _tmp3 = (long int) (arg3);			\

> +  LOAD_ARGS_2 (nm, arg1, arg2)				\

> +  register long int _arg3 __asm__ ("r2") = _tmp3;

> +

> +#define LOAD_ARGS_4(nm, arg1, arg2, arg3, arg4)		\

> +  long int _tmp4 = (long int) (arg4);			\

> +  LOAD_ARGS_3 (nm, arg1, arg2, arg3)			\

> +  register long int _arg4 __asm__ ("r3") = _tmp4;

> +

> +# define LOAD_ARGS_5(nm, arg1, arg2, arg3, arg4, arg5)	\

> +  long int _tmp5 = (long int) (arg5);			\

> +  LOAD_ARGS_4 (nm, arg1, arg2, arg3, arg4)		\

> +  register long int _arg5 __asm__ ("r4") = _tmp5;

> +

> +# define LOAD_ARGS_6(nm,  arg1, arg2, arg3, arg4, arg5, arg6)\

> +  long int _tmp6 = (long int) (arg6);			\

> +  LOAD_ARGS_5 (nm, arg1, arg2, arg3, arg4, arg5)	\

> +  register long int _arg6 __asm__ ("r5") = _tmp6;

> +

> +# define LOAD_ARGS_7(nm, arg1, arg2, arg3, arg4, arg5, arg6, arg7)\

> +  long int _tmp7 = (int) (arg7);				\

> +  LOAD_ARGS_6 (nm, arg1, arg2, arg3, arg4, arg5, arg6)	\

> +  register long int _arg7 __asm__ ("r6") = _tmp7;

> +

> +/* Pointer mangling not yet supported.  */

> +# define PTR_MANGLE(var) (void) (var)

> +# define PTR_DEMANGLE(var) (void) (var)

> +

> +#endif /* !__ASSEMBLER__ */

> +

> +#endif /* linux/arc/sysdep.h */


Ok.

> diff --git a/sysdeps/unix/sysv/linux/arc/vfork.S b/sysdeps/unix/sysv/linux/arc/vfork.S

> new file mode 100644

> index 000000000000..c2ebdd9b6203

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/arc/vfork.S

> @@ -0,0 +1,42 @@

> +/* vfork for ARC Linux.

> +   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 <sys/syscall.h>

> +#include <sysdep.h>

> +#include <tcb-offsets.h>

> +#define _SIGNAL_H

> +#include <bits/signum.h>       /* For SIGCHLD */

> +

> +#define CLONE_VM		0x00000100

> +#define CLONE_VFORK		0x00004000

> +#define CLONE_FLAGS_FOR_VFORK	(CLONE_VM|CLONE_VFORK|SIGCHLD)

> +

> +ENTRY (__vfork)

> +	mov	r0, CLONE_FLAGS_FOR_VFORK

> +	mov_s	r1, sp

> +	mov	r8, __NR_clone

> +	ARC_TRAP_INSN

> +

> +	cmp	r0, 0

> +	jge	[blink]	; child continues

> +

> +	b   __syscall_error

> +PSEUDO_END (__vfork)

> +libc_hidden_def (__vfork)

> +

> +weak_alias (__vfork, vfork)

> 


Ok.
Alistair Francis via Libc-alpha July 4, 2020, 3:54 a.m. | #2
On 7/2/20 7:47 PM, Adhemerval Zanella via Libc-alpha wrote:
> 

> 

> On 30/06/2020 21:08, Vineet Gupta via Libc-alpha wrote:

>> ---

>>    Changes since v7:

>>      - used long int (iso int) in sysdep.h/syscall_error for handling registers

> 

> Patch looks ok, but I have question on the __NR_* undef/define. 

> 


>> diff --git a/sysdeps/unix/sysv/linux/arc/arch-syscall.h b/sysdeps/unix/sysv/linux/arc/arch-syscall.h

...
>> +#define __NR_write 64

>> +#define __NR_writev 66

> 

> Looks good. As side note I think an improvement would be to add

> an annotation on update-syscall-lists.py to specify which kernel

> version it used.


Very good idea indeed. I've asked myself the very question atleast once.


>> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

..
>> +

>> +	; adjust libc args for syscall

> 

> Use the C comment style for constency with rest of the file.


Done.

>> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h


>> +

>> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

>> +   support.  */

>> +

>> +/* fstat64 and fstatat64 need to be replaced with statx.  */

>> +

>> +#undef __NR_fstat64

>> +#undef __NR_fstatat64


This is certainly needed as they are present in ARC arch-syscall.h but we need to
use statx.

>> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

>> +

>> +# undef __NR_clock_adjtime

>> +# undef __NR_clock_getres

>> +# undef __NR_futex

>> +# undef __NR_mq_timedreceive

>> +# undef __NR_mq_timedsend

>> +# undef __NR_ppoll

>> +# undef __NR_pselect6

>> +# undef __NR_recvmmsg

>> +# undef __NR_rt_sigtimedwait

>> +# undef __NR_sched_rr_get_interval

>> +# undef __NR_semtimedop

>> +# undef __NR_timerfd_settime

>> +# undef __NR_timerfd_gettime

>> +# undef __NR_utimensat

> 

> I am trying to understand why these are required since arc does not define 

> them in arch-syscall.h.


arch-syscall.h doesn't define them precisely due to these being here. When
update-syscalls is run, the 32-bit syscalls are generated for ARC (since kernel
ABI provides these because that was v3.9 circa 2013). Adding them
fixup-asm-unistd.h removes them (perhaps I need to add this in changelog to
clarify - atleast for myself).

> And the generic implementation should handle the time64 variant.  If they

> are not this is something we need to handle it.


At the time we we doing this, arch-syscall.h generation was not yet in place,
however I tried to undef in generic/sysdep.h for TIMESIZE==64. However I was asked
me to add this to ARC specific fixup-asm-unistd.h
https://sourceware.org/pipermail/libc-alpha/2020-March/112395.html
https://sourceware.org/pipermail/libc-alpha/2020-April/112909.html

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

...
>> +#define STATFS_IS_STATFS64 0

> 

> Ok.


This specific one is actually dead code. I did post a patch to this effect and
followed up with supporting data that enabling it on 64-bit arches doesn't lead to
any changes in generated code.

https://sourceware.org/pipermail/libc-alpha/2020-February/111259.html
https://sourceware.org/pipermail/libc-alpha/2020-June/115217.html


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


...

>> +/* 32-bit time syscalls are not available, but the redefines allow generic

>> +   wrappers to work.  */

>> +#define __NR_clock_adjtime	__NR_clock_adjtime64

>> +#define __NR_clock_getres	__NR_clock_getres_time64

>> +#define __NR_futex		__NR_futex_time64

>> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

>> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

>> +#define __NR_ppoll		__NR_ppoll_time64

>> +#define __NR_pselect6		__NR_pselect6_time64

>> +#define __NR_recvmmsg		__NR_recvmmsg_time64

>> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

>> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

>> +#define __NR_semtimedop		__NR_semtimedop_time64

>> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

>> +#define __NR_timerfd_settime	__NR_timerfd_settime64

>> +#define __NR_utimensat		__NR_utimensat_time64

> 

> As for the fixup-asm-unistd.h, the generic implementation should handle it

> without the requirement of the ABI to add such tricks.


fixup-asm-unistd.h is different, but this could be avoided. I know for sure that
ll code literally expects __NR_futex (atleast used to). But I can remove this and
see what comes out.

> 

> However it seems that we are still missing support for pselect 

> (__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 

> (__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

> 

> I think we can add the redefine hack only the aforementioned symbols for

> now and removed them once we implement the y2038 support on such symbols

> (since the expected ABI won't change for ARC, only for old ABIs with

> 32 time_t support).


Sorry /me horribly confused here.

>> +

>> +#undef SYS_ify

>> +#define SYS_ify(syscall_name)   __NR_##syscall_name

> 

> The code mixes __NR_* and SYS_ify macro. This macro is really superflous

> and I am preparing some patches to cleanup this up along with C asm

> macros to generate syscall.  So I would suggest to just use the __NR_*

> way and drop this definition.


I don't mind, but it seems that the wrapper was a simply way to avoid open-coding
the macro concatenation. e.g.

# define DO_CALL(syscall_name, args)                    \
-    mov    r8, SYS_ify (syscall_name)  ASM_LINE_SEP    \
+    mov    r8, __NR__##syscall_name  ASM_LINE_SEP    \
     ARC_TRAP_INSN
Alistair Francis via Libc-alpha July 6, 2020, 1:20 p.m. | #3
On 04/07/2020 00:54, Vineet Gupta wrote:
> On 7/2/20 7:47 PM, Adhemerval Zanella via Libc-alpha wrote:

>>

>>

>> On 30/06/2020 21:08, Vineet Gupta via Libc-alpha wrote:

>>> ---

>>>    Changes since v7:

>>>      - used long int (iso int) in sysdep.h/syscall_error for handling registers

>>

>> Patch looks ok, but I have question on the __NR_* undef/define. 

>>

> 

>>> diff --git a/sysdeps/unix/sysv/linux/arc/arch-syscall.h b/sysdeps/unix/sysv/linux/arc/arch-syscall.h

> ...

>>> +#define __NR_write 64

>>> +#define __NR_writev 66

>>

>> Looks good. As side note I think an improvement would be to add

>> an annotation on update-syscall-lists.py to specify which kernel

>> version it used.

> 

> Very good idea indeed. I've asked myself the very question atleast once.

> 

> 

>>> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

> ..

>>> +

>>> +	; adjust libc args for syscall

>>

>> Use the C comment style for constency with rest of the file.

> 

> Done.

> 

>>> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

> 

>>> +

>>> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

>>> +   support.  */

>>> +

>>> +/* fstat64 and fstatat64 need to be replaced with statx.  */

>>> +

>>> +#undef __NR_fstat64

>>> +#undef __NR_fstatat64

> 

> This is certainly needed as they are present in ARC arch-syscall.h but we need to

> use statx.

> 

>>> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

>>> +

>>> +# undef __NR_clock_adjtime

>>> +# undef __NR_clock_getres

>>> +# undef __NR_futex

>>> +# undef __NR_mq_timedreceive

>>> +# undef __NR_mq_timedsend

>>> +# undef __NR_ppoll

>>> +# undef __NR_pselect6

>>> +# undef __NR_recvmmsg

>>> +# undef __NR_rt_sigtimedwait

>>> +# undef __NR_sched_rr_get_interval

>>> +# undef __NR_semtimedop

>>> +# undef __NR_timerfd_settime

>>> +# undef __NR_timerfd_gettime

>>> +# undef __NR_utimensat

>>

>> I am trying to understand why these are required since arc does not define 

>> them in arch-syscall.h.

> 

> arch-syscall.h doesn't define them precisely due to these being here. When

> update-syscalls is run, the 32-bit syscalls are generated for ARC (since kernel

> ABI provides these because that was v3.9 circa 2013). Adding them

> fixup-asm-unistd.h removes them (perhaps I need to add this in changelog to

> clarify - atleast for myself).

> 

>> And the generic implementation should handle the time64 variant.  If they

>> are not this is something we need to handle it.

> 

> At the time we we doing this, arch-syscall.h generation was not yet in place,

> however I tried to undef in generic/sysdep.h for TIMESIZE==64. However I was asked

> me to add this to ARC specific fixup-asm-unistd.h

> https://sourceware.org/pipermail/libc-alpha/2020-March/112395.html

> https://sourceware.org/pipermail/libc-alpha/2020-April/112909.html


My confusion here, I forgot that this header is only used glibcsyscalls.py
to actually generate arch-syscall.h.

You changes does look correct.

> 

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

> ...

>>> +#define STATFS_IS_STATFS64 0

>>

>> Ok.

> 

> This specific one is actually dead code. I did post a patch to this effect and

> followed up with supporting data that enabling it on 64-bit arches doesn't lead to

> any changes in generated code.

> 

> https://sourceware.org/pipermail/libc-alpha/2020-February/111259.html

> https://sourceware.org/pipermail/libc-alpha/2020-June/115217.html

> 


Ack.

> 

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

> 

> ...

> 

>>> +/* 32-bit time syscalls are not available, but the redefines allow generic

>>> +   wrappers to work.  */

>>> +#define __NR_clock_adjtime	__NR_clock_adjtime64

>>> +#define __NR_clock_getres	__NR_clock_getres_time64

>>> +#define __NR_futex		__NR_futex_time64

>>> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

>>> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

>>> +#define __NR_ppoll		__NR_ppoll_time64

>>> +#define __NR_pselect6		__NR_pselect6_time64

>>> +#define __NR_recvmmsg		__NR_recvmmsg_time64

>>> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

>>> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

>>> +#define __NR_semtimedop		__NR_semtimedop_time64

>>> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

>>> +#define __NR_timerfd_settime	__NR_timerfd_settime64

>>> +#define __NR_utimensat		__NR_utimensat_time64

>>

>> As for the fixup-asm-unistd.h, the generic implementation should handle it

>> without the requirement of the ABI to add such tricks.

> 

> fixup-asm-unistd.h is different, but this could be avoided. I know for sure that

> ll code literally expects __NR_futex (atleast used to). But I can remove this and

> see what comes out.

> 

>>

>> However it seems that we are still missing support for pselect 

>> (__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 

>> (__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

>>

>> I think we can add the redefine hack only the aforementioned symbols for

>> now and removed them once we implement the y2038 support on such symbols

>> (since the expected ABI won't change for ARC, only for old ABIs with

>> 32 time_t support).

> 

> Sorry /me horribly confused here.


Sorry for the confusion, I meant that some of these re-defines are superfluous 
and I would like to have the minimum required re-define to enable the ARC 
support, so we can cleanup these later once we enable time64_t support on 
old ABIs as well.

(ignore my comment about fixup-asm-unistd.h, it is related to my confusion
about its internal usage).

> 

>>> +

>>> +#undef SYS_ify

>>> +#define SYS_ify(syscall_name)   __NR_##syscall_name

>>

>> The code mixes __NR_* and SYS_ify macro. This macro is really superflous

>> and I am preparing some patches to cleanup this up along with C asm

>> macros to generate syscall.  So I would suggest to just use the __NR_*

>> way and drop this definition.

> 

> I don't mind, but it seems that the wrapper was a simply way to avoid open-coding

> the macro concatenation. e.g.

> 

> # define DO_CALL(syscall_name, args)                    \

> -    mov    r8, SYS_ify (syscall_name)  ASM_LINE_SEP    \

> +    mov    r8, __NR__##syscall_name  ASM_LINE_SEP    \

>      ARC_TRAP_INSN

> 


My understand was in fact parametrized way to define syscall numbers when
glibc added support to future multiple Unix implementation (which never
actually happened).  I don't have a strong opinion here in fact, any is
fine in the end.
Alistair Francis via Libc-alpha July 7, 2020, 1:25 a.m. | #4
On 7/6/20 6:20 AM, Adhemerval Zanella via Libc-alpha wrote:
>>>> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

>>

>>>> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

>>

>>>> +

>>>> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

>>>> +   support.  */

>>>> +

>>>> +/* fstat64 and fstatat64 need to be replaced with statx.  */

>>>> +

>>>> +#undef __NR_fstat64

>>>> +#undef __NR_fstatat64

>>

>> This is certainly needed as they are present in ARC arch-syscall.h but we need to

>> use statx.

>>

>>>> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

>>>> +

>>>> +# undef __NR_clock_adjtime

>>>> +# undef __NR_clock_getres

>>>> +# undef __NR_futex

>>>> +# undef __NR_mq_timedreceive

>>>> +# undef __NR_mq_timedsend

>>>> +# undef __NR_ppoll

>>>> +# undef __NR_pselect6

>>>> +# undef __NR_recvmmsg

>>>> +# undef __NR_rt_sigtimedwait

>>>> +# undef __NR_sched_rr_get_interval

>>>> +# undef __NR_semtimedop

>>>> +# undef __NR_timerfd_settime

>>>> +# undef __NR_timerfd_gettime

>>>> +# undef __NR_utimensat

>>>

>>> I am trying to understand why these are required since arc does not define 

>>> them in arch-syscall.h.

>>

>> arch-syscall.h doesn't define them precisely due to these being here. When

>> update-syscalls is run, the 32-bit syscalls are generated for ARC (since kernel

>> ABI provides these because that was v3.9 circa 2013). Adding them

>> fixup-asm-unistd.h removes them (perhaps I need to add this in changelog to

>> clarify - atleast for myself).

>>

>>> And the generic implementation should handle the time64 variant.  If they

>>> are not this is something we need to handle it.

>>

>> At the time we we doing this, arch-syscall.h generation was not yet in place,

>> however I tried to undef in generic/sysdep.h for TIMESIZE==64. However I was asked

>> me to add this to ARC specific fixup-asm-unistd.h

>> https://sourceware.org/pipermail/libc-alpha/2020-March/112395.html

>> https://sourceware.org/pipermail/libc-alpha/2020-April/112909.html

> 

> My confusion here, I forgot that this header is only used glibcsyscalls.py

> to actually generate arch-syscall.h.

> 

> You changes does look correct.


Actually we can add a few more entries here which have 64-bit variants.

+# undef __NR_clock_gettime
+# undef __NR_clock_nanosleep
+# undef __NR_clock_settime
+# undef __NR_timer_gettime
+# undef __NR_timer_settime


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


>> This specific one is actually dead code. I did post a patch to this effect and

>> followed up with supporting data that enabling it on 64-bit arches doesn't lead to

>> any changes in generated code.

>>

>> https://sourceware.org/pipermail/libc-alpha/2020-February/111259.html

>> https://sourceware.org/pipermail/libc-alpha/2020-June/115217.html

>>

> 

> Ack.


Thx. I'll repost this after things settle at bit.

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

>>

>> ...

>>

>>>> +/* 32-bit time syscalls are not available, but the redefines allow generic

>>>> +   wrappers to work.  */

>>>> +#define __NR_clock_adjtime	__NR_clock_adjtime64

>>>> +#define __NR_clock_getres	__NR_clock_getres_time64

>>>> +#define __NR_futex		__NR_futex_time64

>>>> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

>>>> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

>>>> +#define __NR_ppoll		__NR_ppoll_time64

>>>> +#define __NR_pselect6		__NR_pselect6_time64

>>>> +#define __NR_recvmmsg		__NR_recvmmsg_time64

>>>> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

>>>> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

>>>> +#define __NR_semtimedop		__NR_semtimedop_time64

>>>> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

>>>> +#define __NR_timerfd_settime	__NR_timerfd_settime64

>>>> +#define __NR_utimensat		__NR_utimensat_time64

>>>

>>> As for the fixup-asm-unistd.h, the generic implementation should handle it

>>> without the requirement of the ABI to add such tricks.

>>

>> fixup-asm-unistd.h is different, but this could be avoided. I know for sure that

>> ll code literally expects __NR_futex (atleast used to). But I can remove this and

>> see what comes out.

>>

>>>

>>> However it seems that we are still missing support for pselect 

>>> (__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 

>>> (__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

>>>

>>> I think we can add the redefine hack only the aforementioned symbols for

>>> now and removed them once we implement the y2038 support on such symbols

>>> (since the expected ABI won't change for ARC, only for old ABIs with

>>> 32 time_t support).

>>

>> Sorry /me horribly confused here.

> 

> Sorry for the confusion, I meant that some of these re-defines are superfluous 

> and I would like to have the minimum required re-define to enable the ARC 

> support, 


Right. The generic code needs a bit more work to eliminate the redefines altogether.

1. Following is not needed

-#define __NR_clock_adjtime     __NR_clock_adjtime64
-#define __NR_sched_rr_get_interval     __NR_sched_rr_get_interval_time64
-#define __NR_mq_timedreceive   __NR_mq_timedreceive_time64
-#define __NR_mq_timedsend      __NR_mq_timedsend_time64
-#define __NR_timerfd_gettime   __NR_timerfd_gettime64
-#define __NR_timerfd_settime   __NR_timerfd_settime64

2. The minimum list needed for ARC (with annotations as to which generic file
needs fixing).

/* Fix sysdeps/unix/sysv/linux/clock_getcpuclockid.c.  */
#define __NR_clock_getres      __NR_clock_getres_time64
/* Fix sysdeps/nptl/lowlevellock-futex.h.  */
#define __NR_futex             __NR_futex_time64
/* Fix sysdeps/unix/sysv/linux/pause.c.  */
#define __NR_ppoll             __NR_ppoll_time64
/* Fix sysdeps/unix/sysv/linux/select.c.  */
#define __NR_pselect6          __NR_pselect6_time64
/* Fix sysdeps/unix/sysv/linux/recvmmsg.c.  */
#define __NR_recvmmsg          __NR_recvmmsg_time64
/* Fix sysdeps/unix/sysv/linux/sigtimedwait.c.  */
#define __NR_rt_sigtimedwait   __NR_rt_sigtimedwait_time64
/* Fix sysdeps/unix/sysv/linux/semtimedop.c.  */
#define __NR_semtimedop                __NR_semtimedop_time64
/* Hack sysdeps/unix/sysv/linux/generic/utimes.c (need linux/utimes.c).  */
#define __NR_utimensat         __NR_utimensat_time64


> so we can cleanup these later once we enable time64_t support on 

> old ABIs as well.


IMO the cleanup applies to new ABIs too as generic code should handle those cases
w/o these workarounds. But that would delay things further for new ports so I
suggest we keep the workarounds and clean things up going fwd.

BTW, if one were to actually go about fixing those, whats the best approach.
Consider the simplest case pause(). For !__NR_pause do we replicate the code for
ppoll/ppoll64 handling or simply just call ppoll(). Later has a function call
overhead) ? Or there is a paradigm to use __syscallxxx_helper() although that
still has a function call overhead.

Actually the pause case is really simple as there are no args, so just redefine
__NR_xxx trick should suffice w/o going into all the explicit
interworking/conversion etc.

__libc_pause (void)
{
#ifdef __NR_pause
  return SYSCALL_CANCEL (pause);
#else

  return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);
#endif


>>>> +#undef SYS_ify

>>>> +#define SYS_ify(syscall_name)   __NR_##syscall_name

>>>

>>> The code mixes __NR_* and SYS_ify macro. This macro is really superflous

>>> and I am preparing some patches to cleanup this up along with C asm

>>> macros to generate syscall.  So I would suggest to just use the __NR_*

>>> way and drop this definition.

>>

>> I don't mind, but it seems that the wrapper was a simply way to avoid open-coding

>> the macro concatenation. e.g.

>>

>> # define DO_CALL(syscall_name, args)                    \

>> -    mov    r8, SYS_ify (syscall_name)  ASM_LINE_SEP    \

>> +    mov    r8, __NR__##syscall_name  ASM_LINE_SEP    \

>>      ARC_TRAP_INSN

>>

> 

> My understand was in fact parametrized way to define syscall numbers when

> glibc added support to future multiple Unix implementation (which never

> actually happened).  I don't have a strong opinion here in fact, any is

> fine in the end.


I open-coded the 2 calls to SYS_ify() in ARC code and deleted SYS_ify()...

... and 2 hrs later, after mysterious build failures, find that SYS_ify() needs to
be retained (even if not used in ARC port) it is expected/used by generic
make-syscalls.h :-(
Alistair Francis via Libc-alpha July 7, 2020, 7:24 p.m. | #5
On 06/07/2020 22:25, Vineet Gupta wrote:
> On 7/6/20 6:20 AM, Adhemerval Zanella via Libc-alpha wrote:

>>>>> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

>>>

>>>>> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

>>>

>>>>> +

>>>>> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

>>>>> +   support.  */

>>>>> +

>>>>> +/* fstat64 and fstatat64 need to be replaced with statx.  */

>>>>> +

>>>>> +#undef __NR_fstat64

>>>>> +#undef __NR_fstatat64

>>>

>>> This is certainly needed as they are present in ARC arch-syscall.h but we need to

>>> use statx.

>>>

>>>>> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

>>>>> +

>>>>> +# undef __NR_clock_adjtime

>>>>> +# undef __NR_clock_getres

>>>>> +# undef __NR_futex

>>>>> +# undef __NR_mq_timedreceive

>>>>> +# undef __NR_mq_timedsend

>>>>> +# undef __NR_ppoll

>>>>> +# undef __NR_pselect6

>>>>> +# undef __NR_recvmmsg

>>>>> +# undef __NR_rt_sigtimedwait

>>>>> +# undef __NR_sched_rr_get_interval

>>>>> +# undef __NR_semtimedop

>>>>> +# undef __NR_timerfd_settime

>>>>> +# undef __NR_timerfd_gettime

>>>>> +# undef __NR_utimensat

>>>>

>>>> I am trying to understand why these are required since arc does not define 

>>>> them in arch-syscall.h.

>>>

>>> arch-syscall.h doesn't define them precisely due to these being here. When

>>> update-syscalls is run, the 32-bit syscalls are generated for ARC (since kernel

>>> ABI provides these because that was v3.9 circa 2013). Adding them

>>> fixup-asm-unistd.h removes them (perhaps I need to add this in changelog to

>>> clarify - atleast for myself).

>>>

>>>> And the generic implementation should handle the time64 variant.  If they

>>>> are not this is something we need to handle it.

>>>

>>> At the time we we doing this, arch-syscall.h generation was not yet in place,

>>> however I tried to undef in generic/sysdep.h for TIMESIZE==64. However I was asked

>>> me to add this to ARC specific fixup-asm-unistd.h

>>> https://sourceware.org/pipermail/libc-alpha/2020-March/112395.html

>>> https://sourceware.org/pipermail/libc-alpha/2020-April/112909.html

>>

>> My confusion here, I forgot that this header is only used glibcsyscalls.py

>> to actually generate arch-syscall.h.

>>

>> You changes does look correct.

> 

> Actually we can add a few more entries here which have 64-bit variants.

> 

> +# undef __NR_clock_gettime

> +# undef __NR_clock_nanosleep

> +# undef __NR_clock_settime

> +# undef __NR_timer_gettime

> +# undef __NR_timer_settime


It should not intefere since ARC also defines __ASSUME_TIME64_SYSCALLS
and the 32-bit fallback syscalls won't be used in this case.

As a side note, now that arch-syscall.h is based on latest kernel version
and all the 32-bit ABIs with old 32-bit time_t have upstream support for 
64-bit time_t we can simplify a bit some implementation by assuming 
the 64-bit time_t is always defined and adding a fallback only for
!define __ASSUME_TIME64_SYSCALLS.


> 

> 

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

> 

>>> This specific one is actually dead code. I did post a patch to this effect and

>>> followed up with supporting data that enabling it on 64-bit arches doesn't lead to

>>> any changes in generated code.

>>>

>>> https://sourceware.org/pipermail/libc-alpha/2020-February/111259.html

>>> https://sourceware.org/pipermail/libc-alpha/2020-June/115217.html

>>>

>>

>> Ack.

> 

> Thx. I'll repost this after things settle at bit.

> 

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

>>>

>>> ...

>>>

>>>>> +/* 32-bit time syscalls are not available, but the redefines allow generic

>>>>> +   wrappers to work.  */

>>>>> +#define __NR_clock_adjtime	__NR_clock_adjtime64

>>>>> +#define __NR_clock_getres	__NR_clock_getres_time64

>>>>> +#define __NR_futex		__NR_futex_time64

>>>>> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

>>>>> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

>>>>> +#define __NR_ppoll		__NR_ppoll_time64

>>>>> +#define __NR_pselect6		__NR_pselect6_time64

>>>>> +#define __NR_recvmmsg		__NR_recvmmsg_time64

>>>>> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

>>>>> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

>>>>> +#define __NR_semtimedop		__NR_semtimedop_time64

>>>>> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

>>>>> +#define __NR_timerfd_settime	__NR_timerfd_settime64

>>>>> +#define __NR_utimensat		__NR_utimensat_time64

>>>>

>>>> As for the fixup-asm-unistd.h, the generic implementation should handle it

>>>> without the requirement of the ABI to add such tricks.

>>>

>>> fixup-asm-unistd.h is different, but this could be avoided. I know for sure that

>>> ll code literally expects __NR_futex (atleast used to). But I can remove this and

>>> see what comes out.

>>>

>>>>

>>>> However it seems that we are still missing support for pselect 

>>>> (__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 

>>>> (__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

>>>>

>>>> I think we can add the redefine hack only the aforementioned symbols for

>>>> now and removed them once we implement the y2038 support on such symbols

>>>> (since the expected ABI won't change for ARC, only for old ABIs with

>>>> 32 time_t support).

>>>

>>> Sorry /me horribly confused here.

>>

>> Sorry for the confusion, I meant that some of these re-defines are superfluous 

>> and I would like to have the minimum required re-define to enable the ARC 

>> support, 

> 

> Right. The generic code needs a bit more work to eliminate the redefines altogether.

> 

> 1. Following is not needed

> 

> -#define __NR_clock_adjtime     __NR_clock_adjtime64

> -#define __NR_sched_rr_get_interval     __NR_sched_rr_get_interval_time64

> -#define __NR_mq_timedreceive   __NR_mq_timedreceive_time64

> -#define __NR_mq_timedsend      __NR_mq_timedsend_time64

> -#define __NR_timerfd_gettime   __NR_timerfd_gettime64

> -#define __NR_timerfd_settime   __NR_timerfd_settime64


Ok.

> 

> 2. The minimum list needed for ARC (with annotations as to which generic file

> needs fixing).

> 

> /* Fix sysdeps/unix/sysv/linux/clock_getcpuclockid.c.  */

> #define __NR_clock_getres      __NR_clock_getres_time64


It should be simple since there is no need to provide an extra symbol
for old ABIs, it would be to just use __NR_clock_getres_time64 if it
is defined.

> /* Fix sysdeps/nptl/lowlevellock-futex.h.  */

> #define __NR_futex             __NR_futex_time64


It seems Lukasz Majewski has sent a patchset to address it (I haven't
checked the detail yet).

> /* Fix sysdeps/unix/sysv/linux/pause.c.  */

> #define __NR_ppoll             __NR_ppoll_time64


This is another one similar to clock_getcpuclockid.

> /* Fix sysdeps/unix/sysv/linux/select.c.  */

> #define __NR_pselect6          __NR_pselect6_time64


I have a patch for select [1], it a bit more complex because we need to 
handle both the timeout and the microblaze lacking support of
pselect6.

> /* Fix sysdeps/unix/sysv/linux/recvmmsg.c.  */

> #define __NR_recvmmsg          __NR_recvmmsg_time64


I also have a patch for this [1], although it still does not have the
ancillary data from struct msghdr which might return SCM_TIMESTAMP
information (which returns struct timespec).  The recvmsg also has
the same issue regarding ancillary data.

> /* Fix sysdeps/unix/sysv/linux/sigtimedwait.c.  */

> #define __NR_rt_sigtimedwait   __NR_rt_sigtimedwait_time64


The patch for is more straighfoward [1].

> /* Fix sysdeps/unix/sysv/linux/semtimedop.c.  */

> #define __NR_semtimedop                __NR_semtimedop_time64


The patch for is also straighfoward [1].


> /* Hack sysdeps/unix/sysv/linux/generic/utimes.c (need linux/utimes.c).  */

> #define __NR_utimensat         __NR_utimensat_time64


Lukasz Majewski also has a patchset for this, I will check this out.

> 

> 

>> so we can cleanup these later once we enable time64_t support on 

>> old ABIs as well.

> 

> IMO the cleanup applies to new ABIs too as generic code should handle those cases

> w/o these workarounds. But that would delay things further for new ports so I

> suggest we keep the workarounds and clean things up going fwd.


I agree, this can be worked in parallel.

> 

> BTW, if one were to actually go about fixing those, whats the best approach.

> Consider the simplest case pause(). For !__NR_pause do we replicate the code for

> ppoll/ppoll64 handling or simply just call ppoll(). Later has a function call

> overhead) ? Or there is a paradigm to use __syscallxxx_helper() although that

> still has a function call overhead.

> 

> Actually the pause case is really simple as there are no args, so just redefine

> __NR_xxx trick should suffice w/o going into all the explicit

> interworking/conversion etc.

> 

> __libc_pause (void)

> {

> #ifdef __NR_pause

>   return SYSCALL_CANCEL (pause);

> #else

> 

>   return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

> #endif

> 


Each implementation has it ows requirements so I can't really say if
a helper function does make sense for all of them.  For pause
specifically we can even simplify to since all architectures have
either ppoll or ppoll_time64:

  int
  __libc_pause (void)
  {
  #ifdef __NR_ppoll_time64
    return SYSCALL_CANCEL (ppoll_time64, NULL, 0, NULL, NULL);
  #else
    return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);
  #endif
  }
> 

>>>>> +#undef SYS_ify

>>>>> +#define SYS_ify(syscall_name)   __NR_##syscall_name

>>>>

>>>> The code mixes __NR_* and SYS_ify macro. This macro is really superflous

>>>> and I am preparing some patches to cleanup this up along with C asm

>>>> macros to generate syscall.  So I would suggest to just use the __NR_*

>>>> way and drop this definition.

>>>

>>> I don't mind, but it seems that the wrapper was a simply way to avoid open-coding

>>> the macro concatenation. e.g.

>>>

>>> # define DO_CALL(syscall_name, args)                    \

>>> -    mov    r8, SYS_ify (syscall_name)  ASM_LINE_SEP    \

>>> +    mov    r8, __NR__##syscall_name  ASM_LINE_SEP    \

>>>      ARC_TRAP_INSN

>>>

>>

>> My understand was in fact parametrized way to define syscall numbers when

>> glibc added support to future multiple Unix implementation (which never

>> actually happened).  I don't have a strong opinion here in fact, any is

>> fine in the end.

> 

> I open-coded the 2 calls to SYS_ify() in ARC code and deleted SYS_ify()...

> 

> ... and 2 hrs later, after mysterious build failures, find that SYS_ify() needs to

> be retained (even if not used in ARC port) it is expected/used by generic

> make-syscalls.h :-(


Sigh, alright let keep it then.

[1] https://sourceware.org/git/?p=glibc.git;a=shortlog;h=refs/heads/azanella/y2038-fixes
Alistair Francis via Libc-alpha July 7, 2020, 9:07 p.m. | #6
On 7/7/20 12:24 PM, Adhemerval Zanella via Libc-alpha wrote:
> 

> 

> On 06/07/2020 22:25, Vineet Gupta wrote:

>> On 7/6/20 6:20 AM, Adhemerval Zanella via Libc-alpha wrote:

>>>>>> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S

>>>>

>>>>>> diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h

>>>>

>>>>>> +

>>>>>> +/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t

>>>>>> +   support.  */

>>>>>> +

>>>>>> +/* fstat64 and fstatat64 need to be replaced with statx.  */

>>>>>> +

>>>>>> +#undef __NR_fstat64

>>>>>> +#undef __NR_fstatat64

>>>>

>>>> This is certainly needed as they are present in ARC arch-syscall.h but we need to

>>>> use statx.

>>>>

>>>>>> +/* Replace all other 32-bit time syscalls with 64-bit variants.  */

>>>>>> +

>>>>>> +# undef __NR_clock_adjtime

>>>>>> +# undef __NR_clock_getres

>>>>>> +# undef __NR_futex

>>>>>> +# undef __NR_mq_timedreceive

>>>>>> +# undef __NR_mq_timedsend

>>>>>> +# undef __NR_ppoll

>>>>>> +# undef __NR_pselect6

>>>>>> +# undef __NR_recvmmsg

>>>>>> +# undef __NR_rt_sigtimedwait

>>>>>> +# undef __NR_sched_rr_get_interval

>>>>>> +# undef __NR_semtimedop

>>>>>> +# undef __NR_timerfd_settime

>>>>>> +# undef __NR_timerfd_gettime

>>>>>> +# undef __NR_utimensat

>>>>>

>>>>> I am trying to understand why these are required since arc does not define 

>>>>> them in arch-syscall.h.

>>>>

>>>> arch-syscall.h doesn't define them precisely due to these being here. When

>>>> update-syscalls is run, the 32-bit syscalls are generated for ARC (since kernel

>>>> ABI provides these because that was v3.9 circa 2013). Adding them

>>>> fixup-asm-unistd.h removes them (perhaps I need to add this in changelog to

>>>> clarify - atleast for myself).

>>>>

>>>>> And the generic implementation should handle the time64 variant.  If they

>>>>> are not this is something we need to handle it.

>>>>

>>>> At the time we we doing this, arch-syscall.h generation was not yet in place,

>>>> however I tried to undef in generic/sysdep.h for TIMESIZE==64. However I was asked

>>>> me to add this to ARC specific fixup-asm-unistd.h

>>>> https://sourceware.org/pipermail/libc-alpha/2020-March/112395.html

>>>> https://sourceware.org/pipermail/libc-alpha/2020-April/112909.html

>>>

>>> My confusion here, I forgot that this header is only used glibcsyscalls.py

>>> to actually generate arch-syscall.h.

>>>

>>> You changes does look correct.

>>

>> Actually we can add a few more entries here which have 64-bit variants.

>>

>> +# undef __NR_clock_gettime

>> +# undef __NR_clock_nanosleep

>> +# undef __NR_clock_settime

>> +# undef __NR_timer_gettime

>> +# undef __NR_timer_settime

> 

> It should not intefere since ARC also defines __ASSUME_TIME64_SYSCALLS

> and the 32-bit fallback syscalls won't be used in this case.


In an ideal world yes, but as we see from hacks in sysdep.h, there's code which
build/works inadvertently. If nothing else, this documents that those syscalls are
not to be used.


> As a side note, now that arch-syscall.h is based on latest kernel version

> and all the 32-bit ABIs with old 32-bit time_t have upstream support for 

> 64-bit time_t we can simplify a bit some implementation by assuming 

> the 64-bit time_t is always defined and adding a fallback only for

> !define __ASSUME_TIME64_SYSCALLS.


OK.

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

>>>>

>>>> ...

>>>>

>>>>>> +/* 32-bit time syscalls are not available, but the redefines allow generic

>>>>>> +   wrappers to work.  */

>>>>>> +#define __NR_clock_adjtime	__NR_clock_adjtime64

>>>>>> +#define __NR_clock_getres	__NR_clock_getres_time64

>>>>>> +#define __NR_futex		__NR_futex_time64

>>>>>> +#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64

>>>>>> +#define __NR_mq_timedsend	__NR_mq_timedsend_time64

>>>>>> +#define __NR_ppoll		__NR_ppoll_time64

>>>>>> +#define __NR_pselect6		__NR_pselect6_time64

>>>>>> +#define __NR_recvmmsg		__NR_recvmmsg_time64

>>>>>> +#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64

>>>>>> +#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64

>>>>>> +#define __NR_semtimedop		__NR_semtimedop_time64

>>>>>> +#define __NR_timerfd_gettime	__NR_timerfd_gettime64

>>>>>> +#define __NR_timerfd_settime	__NR_timerfd_settime64

>>>>>> +#define __NR_utimensat		__NR_utimensat_time64

>>>>>

>>>>> As for the fixup-asm-unistd.h, the generic implementation should handle it

>>>>> without the requirement of the ABI to add such tricks.

>>>>

>>>> fixup-asm-unistd.h is different, but this could be avoided. I know for sure that

>>>> ll code literally expects __NR_futex (atleast used to). But I can remove this and

>>>> see what comes out.

>>>>

>>>>>

>>>>> However it seems that we are still missing support for pselect 

>>>>> (__NR_pselect6_time64), recvmmsg (__NR_recvmmsg_time64), sigtimedwait 

>>>>> (__NR_rt_sigtimedwait_time64), and semtimeop (__NR_semtimedop_time64).

>>>>>

>>>>> I think we can add the redefine hack only the aforementioned symbols for

>>>>> now and removed them once we implement the y2038 support on such symbols

>>>>> (since the expected ABI won't change for ARC, only for old ABIs with

>>>>> 32 time_t support).

>>>>

>>>> Sorry /me horribly confused here.

>>>

>>> Sorry for the confusion, I meant that some of these re-defines are superfluous 

>>> and I would like to have the minimum required re-define to enable the ARC 

>>> support, 

>>

>> Right. The generic code needs a bit more work to eliminate the redefines altogether.

>>

>> 1. Following is not needed

>>

>> -#define __NR_clock_adjtime     __NR_clock_adjtime64

>> -#define __NR_sched_rr_get_interval     __NR_sched_rr_get_interval_time64

>> -#define __NR_mq_timedreceive   __NR_mq_timedreceive_time64

>> -#define __NR_mq_timedsend      __NR_mq_timedsend_time64

>> -#define __NR_timerfd_gettime   __NR_timerfd_gettime64

>> -#define __NR_timerfd_settime   __NR_timerfd_settime64

> 

> Ok.

> 

>>

>> 2. The minimum list needed for ARC (with annotations as to which generic file

>> needs fixing).

>>

>> /* Fix sysdeps/unix/sysv/linux/clock_getcpuclockid.c.  */

>> #define __NR_clock_getres      __NR_clock_getres_time64

> 

> It should be simple since there is no need to provide an extra symbol

> for old ABIs, it would be to just use __NR_clock_getres_time64 if it

> is defined.

> 

>> /* Fix sysdeps/nptl/lowlevellock-futex.h.  */

>> #define __NR_futex             __NR_futex_time64

> 

> It seems Lukasz Majewski has sent a patchset to address it (I haven't

> checked the detail yet).

> 

>> /* Fix sysdeps/unix/sysv/linux/pause.c.  */

>> #define __NR_ppoll             __NR_ppoll_time64

> 

> This is another one similar to clock_getcpuclockid.

> 

>> /* Fix sysdeps/unix/sysv/linux/select.c.  */

>> #define __NR_pselect6          __NR_pselect6_time64

> 

> I have a patch for select [1], it a bit more complex because we need to 

> handle both the timeout and the microblaze lacking support of

> pselect6.

> 

>> /* Fix sysdeps/unix/sysv/linux/recvmmsg.c.  */

>> #define __NR_recvmmsg          __NR_recvmmsg_time64

> 

> I also have a patch for this [1], although it still does not have the

> ancillary data from struct msghdr which might return SCM_TIMESTAMP

> information (which returns struct timespec).  The recvmsg also has

> the same issue regarding ancillary data.

> 

>> /* Fix sysdeps/unix/sysv/linux/sigtimedwait.c.  */

>> #define __NR_rt_sigtimedwait   __NR_rt_sigtimedwait_time64

> 

> The patch for is more straighfoward [1].

> 

>> /* Fix sysdeps/unix/sysv/linux/semtimedop.c.  */

>> #define __NR_semtimedop                __NR_semtimedop_time64

> 

> The patch for is also straighfoward [1].

> 

> 

>> /* Hack sysdeps/unix/sysv/linux/generic/utimes.c (need linux/utimes.c).  */

>> #define __NR_utimensat         __NR_utimensat_time64

> 

> Lukasz Majewski also has a patchset for this, I will check this out.


Thanks for tacking this.

>>> so we can cleanup these later once we enable time64_t support on 

>>> old ABIs as well.

>>

>> IMO the cleanup applies to new ABIs too as generic code should handle those cases

>> w/o these workarounds. But that would delay things further for new ports so I

>> suggest we keep the workarounds and clean things up going fwd.

> 

> I agree, this can be worked in parallel.


Thx for being pragmatic. Given ABI freeze we will merge ARC with workarounds and
clean them up in 2.33 ?

>> BTW, if one were to actually go about fixing those, whats the best approach.

>> Consider the simplest case pause(). For !__NR_pause do we replicate the code for

>> ppoll/ppoll64 handling or simply just call ppoll(). Later has a function call

>> overhead) ? Or there is a paradigm to use __syscallxxx_helper() although that

>> still has a function call overhead.

>>

>> Actually the pause case is really simple as there are no args, so just redefine

>> __NR_xxx trick should suffice w/o going into all the explicit

>> interworking/conversion etc.

>>

>> __libc_pause (void)

>> {

>> #ifdef __NR_pause

>>   return SYSCALL_CANCEL (pause);

>> #else

>>

>>   return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

>> #endif

>>

> 

> Each implementation has it ows requirements so I can't really say if

> a helper function does make sense for all of them.  For pause

> specifically we can even simplify to since all architectures have

> either ppoll or ppoll_time64:

> 

>   int

>   __libc_pause (void)

>   {

>   #ifdef __NR_ppoll_time64

>     return SYSCALL_CANCEL (ppoll_time64, NULL, 0, NULL, NULL);

>   #else

>     return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

>   #endif

>   }


But how is this compatible with older kernels (and perhaps this is a general
question). I mean one/more ABIs minimum kernel would not have the ppoll or ppoll64
so how will new glibc work with such a kernel ? Is it not required to ?
Joseph Myers July 7, 2020, 9:32 p.m. | #7
On Tue, 7 Jul 2020, Vineet Gupta via Libc-alpha wrote:

> > Each implementation has it ows requirements so I can't really say if

> > a helper function does make sense for all of them.  For pause

> > specifically we can even simplify to since all architectures have

> > either ppoll or ppoll_time64:

> > 

> >   int

> >   __libc_pause (void)

> >   {

> >   #ifdef __NR_ppoll_time64

> >     return SYSCALL_CANCEL (ppoll_time64, NULL, 0, NULL, NULL);

> >   #else

> >     return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

> >   #endif

> >   }

> 

> But how is this compatible with older kernels (and perhaps this is a general

> question). I mean one/more ABIs minimum kernel would not have the ppoll or ppoll64

> so how will new glibc work with such a kernel ? Is it not required to ?


See commit 089b772f98afd9eb6264c6489bc96a30bf6af4ac, where I removed 
__ASSUME_PPOLL because all supported kernel versions now had that syscall 
for all glibc architectures.

In general this sort of thing needs a review of whether a given syscall is 
available for all glibc architectures in their minimum kernel versions.  
For the old kernels in question, that means checking the 
architecture-specific syscall table as used to dispatch syscalls at 
runtime, which used to have an architecture-specific format before 
unification work was done; it used to mean checking asm/unistd.h as well, 
but now we have syscall tables in glibc that's probably no longer 
required.  It also involves checking compat syscall tables for 32-bit 
binaries on 64-bit kernels, as sometimes a syscall didn't get added to the 
native and compat syscall tables at the same time (see the comments in 
sparc/kernel-features.h about various socket-related syscalls, for 
example).

-- 
Joseph S. Myers
joseph@codesourcery.com
Alistair Francis via Libc-alpha July 7, 2020, 11:16 p.m. | #8
On 7/7/20 2:32 PM, Joseph Myers wrote:
> On Tue, 7 Jul 2020, Vineet Gupta via Libc-alpha wrote:

> 

>>> Each implementation has it ows requirements so I can't really say if

>>> a helper function does make sense for all of them.  For pause

>>> specifically we can even simplify to since all architectures have

>>> either ppoll or ppoll_time64:

>>>

>>>   int

>>>   __libc_pause (void)

>>>   {

>>>   #ifdef __NR_ppoll_time64

>>>     return SYSCALL_CANCEL (ppoll_time64, NULL, 0, NULL, NULL);

>>>   #else

>>>     return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

>>>   #endif

>>>   }

>>

>> But how is this compatible with older kernels (and perhaps this is a general

>> question). I mean one/more ABIs minimum kernel would not have the ppoll or ppoll64

>> so how will new glibc work with such a kernel ? Is it not required to ?

> 

> See commit 089b772f98afd9eb6264c6489bc96a30bf6af4ac, where I removed 

> __ASSUME_PPOLL because all supported kernel versions now had that syscall 

> for all glibc architectures.


But that still doesn't explain how new glibc works with old kernels (for say when
a port support was first merged, with say asm-generic ABI).

Ah it seems any glibc is only required to work with "arch_minimum_kernel" (generic
or architecture override) which over time itself keeps moving forward due to
various reasons (e.g. 64-bit time support etc). So indeed a bleeding edge glibc of
today won't necessarily work with an arch kernel for say when its glibc port was
first merged, but will for the corresponding arch_minimum_kernel.

> In general this sort of thing needs a review of whether a given syscall is 

> available for all glibc architectures in their minimum kernel versions.  

> For the old kernels in question, that means checking the 

> architecture-specific syscall table as used to dispatch syscalls at 

> runtime, which used to have an architecture-specific format before 

> unification work was done; it used to mean checking asm/unistd.h as well, 

> but now we have syscall tables in glibc that's probably no longer 

> required.  It also involves checking compat syscall tables for 32-bit 

> binaries on 64-bit kernels, as sometimes a syscall didn't get added to the 

> native and compat syscall tables at the same time (see the comments in 

> sparc/kernel-features.h about various socket-related syscalls, for 

> example).

>
Alistair Francis via Libc-alpha July 8, 2020, 4:27 p.m. | #9
On 07/07/2020 20:16, Vineet Gupta via Libc-alpha wrote:
> On 7/7/20 2:32 PM, Joseph Myers wrote:

>> On Tue, 7 Jul 2020, Vineet Gupta via Libc-alpha wrote:

>>

>>>> Each implementation has it ows requirements so I can't really say if

>>>> a helper function does make sense for all of them.  For pause

>>>> specifically we can even simplify to since all architectures have

>>>> either ppoll or ppoll_time64:

>>>>

>>>>   int

>>>>   __libc_pause (void)

>>>>   {

>>>>   #ifdef __NR_ppoll_time64

>>>>     return SYSCALL_CANCEL (ppoll_time64, NULL, 0, NULL, NULL);

>>>>   #else

>>>>     return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);

>>>>   #endif

>>>>   }

>>>

>>> But how is this compatible with older kernels (and perhaps this is a general

>>> question). I mean one/more ABIs minimum kernel would not have the ppoll or ppoll64

>>> so how will new glibc work with such a kernel ? Is it not required to ?

>>

>> See commit 089b772f98afd9eb6264c6489bc96a30bf6af4ac, where I removed 

>> __ASSUME_PPOLL because all supported kernel versions now had that syscall 

>> for all glibc architectures.

> 

> But that still doesn't explain how new glibc works with old kernels (for say when

> a port support was first merged, with say asm-generic ABI).

> 

> Ah it seems any glibc is only required to work with "arch_minimum_kernel" (generic

> or architecture override) which over time itself keeps moving forward due to

> various reasons (e.g. 64-bit time support etc). So indeed a bleeding edge glibc of

> today won't necessarily work with an arch kernel for say when its glibc port was

> first merged, but will for the corresponding arch_minimum_kernel.


Yes, each releases sets a minimum requires kernel as default and each
architecture and/or ABI can raise if required.  The default minimum
is 3.2.

It allows us to make some assumptions and simplify the implementation
for some symbols.  For instance, currently microblaze still does not
provide a pselect6 syscall for kernels older than 3.15 and thus it 
requires an specific pselect implementation that call sigprocmask and
select.

And in most cases such fallbacks are error prone, provide subpar
implementations (the pselect in microblaze ends up to being atomically
regarding signal handling which is the whole idea of the syscall),
and add more code complexity (to handle multiple permutations to avoid 
building the fallback itself).

Patch

diff --git a/sysdeps/unix/sysv/linux/arc/arch-syscall.h b/sysdeps/unix/sysv/linux/arc/arch-syscall.h
new file mode 100644
index 000000000000..2b017eb5bbaa
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/arch-syscall.h
@@ -0,0 +1,303 @@ 
+/* AUTOGENERATED by update-syscall-lists.py.  */
+#define __NR_accept 202
+#define __NR_accept4 242
+#define __NR_acct 89
+#define __NR_add_key 217
+#define __NR_adjtimex 171
+#define __NR_arc_gettls 246
+#define __NR_arc_settls 245
+#define __NR_arc_usr_cmpxchg 248
+#define __NR_bind 200
+#define __NR_bpf 280
+#define __NR_brk 214
+#define __NR_cacheflush 244
+#define __NR_capget 90
+#define __NR_capset 91
+#define __NR_chdir 49
+#define __NR_chroot 51
+#define __NR_clock_adjtime64 405
+#define __NR_clock_getres_time64 406
+#define __NR_clock_gettime 113
+#define __NR_clock_gettime64 403
+#define __NR_clock_nanosleep 115
+#define __NR_clock_nanosleep_time64 407
+#define __NR_clock_settime 112
+#define __NR_clock_settime64 404
+#define __NR_clone 220
+#define __NR_clone3 435
+#define __NR_close 57
+#define __NR_connect 203
+#define __NR_copy_file_range 285
+#define __NR_delete_module 106
+#define __NR_dup 23
+#define __NR_dup3 24
+#define __NR_epoll_create1 20
+#define __NR_epoll_ctl 21
+#define __NR_epoll_pwait 22
+#define __NR_eventfd2 19
+#define __NR_execve 221
+#define __NR_execveat 281
+#define __NR_exit 93
+#define __NR_exit_group 94
+#define __NR_faccessat 48
+#define __NR_fadvise64_64 223
+#define __NR_fallocate 47
+#define __NR_fanotify_init 262
+#define __NR_fanotify_mark 263
+#define __NR_fchdir 50
+#define __NR_fchmod 52
+#define __NR_fchmodat 53
+#define __NR_fchown 55
+#define __NR_fchownat 54
+#define __NR_fcntl64 25
+#define __NR_fdatasync 83
+#define __NR_fgetxattr 10
+#define __NR_finit_module 273
+#define __NR_flistxattr 13
+#define __NR_flock 32
+#define __NR_fremovexattr 16
+#define __NR_fsconfig 431
+#define __NR_fsetxattr 7
+#define __NR_fsmount 432
+#define __NR_fsopen 430
+#define __NR_fspick 433
+#define __NR_fstatfs64 44
+#define __NR_fsync 82
+#define __NR_ftruncate64 46
+#define __NR_futex_time64 422
+#define __NR_get_mempolicy 236
+#define __NR_get_robust_list 100
+#define __NR_getcpu 168
+#define __NR_getcwd 17
+#define __NR_getdents64 61
+#define __NR_getegid 177
+#define __NR_geteuid 175
+#define __NR_getgid 176
+#define __NR_getgroups 158
+#define __NR_getitimer 102
+#define __NR_getpeername 205
+#define __NR_getpgid 155
+#define __NR_getpid 172
+#define __NR_getppid 173
+#define __NR_getpriority 141
+#define __NR_getrandom 278
+#define __NR_getresgid 150
+#define __NR_getresuid 148
+#define __NR_getrlimit 163
+#define __NR_getrusage 165
+#define __NR_getsid 156
+#define __NR_getsockname 204
+#define __NR_getsockopt 209
+#define __NR_gettid 178
+#define __NR_gettimeofday 169
+#define __NR_getuid 174
+#define __NR_getxattr 8
+#define __NR_init_module 105
+#define __NR_inotify_add_watch 27
+#define __NR_inotify_init1 26
+#define __NR_inotify_rm_watch 28
+#define __NR_io_cancel 3
+#define __NR_io_destroy 1
+#define __NR_io_getevents 4
+#define __NR_io_pgetevents 292
+#define __NR_io_pgetevents_time64 416
+#define __NR_io_setup 0
+#define __NR_io_submit 2
+#define __NR_io_uring_enter 426
+#define __NR_io_uring_register 427
+#define __NR_io_uring_setup 425
+#define __NR_ioctl 29
+#define __NR_ioprio_get 31
+#define __NR_ioprio_set 30
+#define __NR_kcmp 272
+#define __NR_kexec_file_load 294
+#define __NR_kexec_load 104
+#define __NR_keyctl 219
+#define __NR_kill 129
+#define __NR_lgetxattr 9
+#define __NR_linkat 37
+#define __NR_listen 201
+#define __NR_listxattr 11
+#define __NR_llistxattr 12
+#define __NR_llseek 62
+#define __NR_lookup_dcookie 18
+#define __NR_lremovexattr 15
+#define __NR_lsetxattr 6
+#define __NR_madvise 233
+#define __NR_mbind 235
+#define __NR_membarrier 283
+#define __NR_memfd_create 279
+#define __NR_migrate_pages 238
+#define __NR_mincore 232
+#define __NR_mkdirat 34
+#define __NR_mknodat 33
+#define __NR_mlock 228
+#define __NR_mlock2 284
+#define __NR_mlockall 230
+#define __NR_mmap2 222
+#define __NR_mount 40
+#define __NR_move_mount 429
+#define __NR_move_pages 239
+#define __NR_mprotect 226
+#define __NR_mq_getsetattr 185
+#define __NR_mq_notify 184
+#define __NR_mq_open 180
+#define __NR_mq_timedreceive_time64 419
+#define __NR_mq_timedsend_time64 418
+#define __NR_mq_unlink 181
+#define __NR_mremap 216
+#define __NR_msgctl 187
+#define __NR_msgget 186
+#define __NR_msgrcv 188
+#define __NR_msgsnd 189
+#define __NR_msync 227
+#define __NR_munlock 229
+#define __NR_munlockall 231
+#define __NR_munmap 215
+#define __NR_name_to_handle_at 264
+#define __NR_nanosleep 101
+#define __NR_nfsservctl 42
+#define __NR_open_by_handle_at 265
+#define __NR_open_tree 428
+#define __NR_openat 56
+#define __NR_openat2 437
+#define __NR_perf_event_open 241
+#define __NR_personality 92
+#define __NR_pidfd_getfd 438
+#define __NR_pidfd_open 434
+#define __NR_pidfd_send_signal 424
+#define __NR_pipe2 59
+#define __NR_pivot_root 41
+#define __NR_pkey_alloc 289
+#define __NR_pkey_free 290
+#define __NR_pkey_mprotect 288
+#define __NR_ppoll_time64 414
+#define __NR_prctl 167
+#define __NR_pread64 67
+#define __NR_preadv 69
+#define __NR_preadv2 286
+#define __NR_prlimit64 261
+#define __NR_process_vm_readv 270
+#define __NR_process_vm_writev 271
+#define __NR_pselect6_time64 413
+#define __NR_ptrace 117
+#define __NR_pwrite64 68
+#define __NR_pwritev 70
+#define __NR_pwritev2 287
+#define __NR_quotactl 60
+#define __NR_read 63
+#define __NR_readahead 213
+#define __NR_readlinkat 78
+#define __NR_readv 65
+#define __NR_reboot 142
+#define __NR_recvfrom 207
+#define __NR_recvmmsg_time64 417
+#define __NR_recvmsg 212
+#define __NR_remap_file_pages 234
+#define __NR_removexattr 14
+#define __NR_renameat 38
+#define __NR_renameat2 276
+#define __NR_request_key 218
+#define __NR_restart_syscall 128
+#define __NR_rseq 293
+#define __NR_rt_sigaction 134
+#define __NR_rt_sigpending 136
+#define __NR_rt_sigprocmask 135
+#define __NR_rt_sigqueueinfo 138
+#define __NR_rt_sigreturn 139
+#define __NR_rt_sigsuspend 133
+#define __NR_rt_sigtimedwait_time64 421
+#define __NR_rt_tgsigqueueinfo 240
+#define __NR_sched_get_priority_max 125
+#define __NR_sched_get_priority_min 126
+#define __NR_sched_getaffinity 123
+#define __NR_sched_getattr 275
+#define __NR_sched_getparam 121
+#define __NR_sched_getscheduler 120
+#define __NR_sched_rr_get_interval_time64 423
+#define __NR_sched_setaffinity 122
+#define __NR_sched_setattr 274
+#define __NR_sched_setparam 118
+#define __NR_sched_setscheduler 119
+#define __NR_sched_yield 124
+#define __NR_seccomp 277
+#define __NR_semctl 191
+#define __NR_semget 190
+#define __NR_semop 193
+#define __NR_semtimedop_time64 420
+#define __NR_sendfile64 71
+#define __NR_sendmmsg 269
+#define __NR_sendmsg 211
+#define __NR_sendto 206
+#define __NR_set_mempolicy 237
+#define __NR_set_robust_list 99
+#define __NR_set_tid_address 96
+#define __NR_setdomainname 162
+#define __NR_setfsgid 152
+#define __NR_setfsuid 151
+#define __NR_setgid 144
+#define __NR_setgroups 159
+#define __NR_sethostname 161
+#define __NR_setitimer 103
+#define __NR_setns 268
+#define __NR_setpgid 154
+#define __NR_setpriority 140
+#define __NR_setregid 143
+#define __NR_setresgid 149
+#define __NR_setresuid 147
+#define __NR_setreuid 145
+#define __NR_setrlimit 164
+#define __NR_setsid 157
+#define __NR_setsockopt 208
+#define __NR_settimeofday 170
+#define __NR_setuid 146
+#define __NR_setxattr 5
+#define __NR_shmat 196
+#define __NR_shmctl 195
+#define __NR_shmdt 197
+#define __NR_shmget 194
+#define __NR_shutdown 210
+#define __NR_sigaltstack 132
+#define __NR_signalfd4 74
+#define __NR_socket 198
+#define __NR_socketpair 199
+#define __NR_splice 76
+#define __NR_statfs64 43
+#define __NR_statx 291
+#define __NR_swapoff 225
+#define __NR_swapon 224
+#define __NR_symlinkat 36
+#define __NR_sync 81
+#define __NR_sync_file_range 84
+#define __NR_syncfs 267
+#define __NR_sysfs 247
+#define __NR_sysinfo 179
+#define __NR_syslog 116
+#define __NR_tee 77
+#define __NR_tgkill 131
+#define __NR_timer_create 107
+#define __NR_timer_delete 111
+#define __NR_timer_getoverrun 109
+#define __NR_timer_gettime 108
+#define __NR_timer_gettime64 408
+#define __NR_timer_settime 110
+#define __NR_timer_settime64 409
+#define __NR_timerfd_create 85
+#define __NR_timerfd_gettime64 410
+#define __NR_timerfd_settime64 411
+#define __NR_times 153
+#define __NR_tkill 130
+#define __NR_truncate64 45
+#define __NR_umask 166
+#define __NR_umount2 39
+#define __NR_uname 160
+#define __NR_unlinkat 35
+#define __NR_unshare 97
+#define __NR_userfaultfd 282
+#define __NR_utimensat_time64 412
+#define __NR_vhangup 58
+#define __NR_vmsplice 75
+#define __NR_wait4 260
+#define __NR_waitid 95
+#define __NR_write 64
+#define __NR_writev 66
diff --git a/sysdeps/unix/sysv/linux/arc/bits/timesize.h b/sysdeps/unix/sysv/linux/arc/bits/timesize.h
new file mode 100644
index 000000000000..bf44f09f7619
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/bits/timesize.h
@@ -0,0 +1,21 @@ 
+/* Bit size of the time_t type at glibc build time, general case.
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <bits/wordsize.h>
+
+#define __TIMESIZE	64
diff --git a/sysdeps/unix/sysv/linux/arc/clone.S b/sysdeps/unix/sysv/linux/arc/clone.S
new file mode 100644
index 000000000000..035b285ff98f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/clone.S
@@ -0,0 +1,93 @@ 
+/* clone() implementation for ARC.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Andrew Jenner <andrew@codesourcery.com>, 2008.
+
+   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 <sysdep.h>
+#define _ERRNO_H	1
+#include <bits/errno.h>
+#include <tcb-offsets.h>
+
+#define CLONE_SETTLS		0x00080000
+
+/* int clone(int (*fn)(void *), void *child_stack,
+           int flags, void *arg, ...
+           < pid_t *ptid, struct user_desc *tls, pid_t *ctid > );
+
+ NOTE: I'm assuming that the last 3 args are NOT var-args and in case all
+	3 are not relevant, caller will nevertheless pass those as NULL.
+
+ clone syscall in kernel (ABI: CONFIG_CLONE_BACKWARDS)
+
+  int sys_clone(unsigned long int clone_flags,
+	        unsigned long int newsp,
+		int __user *parent_tidptr,
+		void *tls,
+		int __user *child_tidptr).  */
+
+ENTRY (__clone)
+	cmp	r0, 0		/* @fn can't be NULL.  */
+	cmp.ne	r1, 0		/* @child_stack can't be NULL.  */
+	bz	L (__sys_err)
+
+	/* save some of the orig args
+	   r0 containg @fn will be clobbered AFTER syscall (with ret val)
+	   rest are clobbered BEFORE syscall due to different arg ordering.  */
+	mov	r10, r0		/* @fn.  */
+	mov	r11, r3		/* @args.  */
+	mov	r12, r2		/* @clone_flags.  */
+	mov	r9,  r5		/* @tls.  */
+
+	; adjust libc args for syscall
+
+	mov 	r0, r2		/* libc @flags is 1st syscall arg.  */
+	mov	r2, r4		/* libc @ptid.  */
+	mov	r3, r5		/* libc @tls.  */
+	mov	r4, r6		/* libc @ctid.  */
+	mov	r8, __NR_clone
+	ARC_TRAP_INSN
+
+	cmp	r0, 0		/* return code : 0 new process, !0 parent.  */
+	blt	L (__sys_err2)	/* < 0 (signed) error.  */
+	jnz	[blink]		/* Parent returns.  */
+
+	/* child jumps off to @fn with @arg as argument
+           TP register already set by kernel.  */
+	jl.d	[r10]
+	mov	r0, r11
+
+	/* exit() with result from @fn (already in r0).  */
+	mov	r8, __NR_exit
+	ARC_TRAP_INSN
+	/* In case it ever came back.  */
+	flag	1
+
+L (__sys_err):
+	mov	r0, -EINVAL
+L (__sys_err2):
+	/* (1) No need to make -ve kernel error code as positive errno
+	       __syscall_error expects the -ve error code returned by kernel
+	   (2) r0 still had orig -ve kernel error code
+	   (3) Tail call to __syscall_error so we dont have to come back
+	       here hence instead of jmp-n-link (reg push/pop) we do jmp
+	   (4) No need to route __syscall_error via PLT, B is inherently
+	       position independent.  */
+	b   __syscall_error
+PSEUDO_END (__clone)
+libc_hidden_def (__clone)
+weak_alias (__clone, clone)
diff --git a/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h
new file mode 100644
index 000000000000..47faaecc8970
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/fixup-asm-unistd.h
@@ -0,0 +1,41 @@ 
+/* Regularize <asm/unistd.h> definitions.  ARC version.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* Adjustments to ARC asm-generic syscall ABI (3.9 kernel) for 64-bit time_t
+   support.  */
+
+/* fstat64 and fstatat64 need to be replaced with statx.  */
+
+#undef __NR_fstat64
+#undef __NR_fstatat64
+
+/* Replace all other 32-bit time syscalls with 64-bit variants.  */
+
+# undef __NR_clock_adjtime
+# undef __NR_clock_getres
+# undef __NR_futex
+# undef __NR_mq_timedreceive
+# undef __NR_mq_timedsend
+# undef __NR_ppoll
+# undef __NR_pselect6
+# undef __NR_recvmmsg
+# undef __NR_rt_sigtimedwait
+# undef __NR_sched_rr_get_interval
+# undef __NR_semtimedop
+# undef __NR_timerfd_settime
+# undef __NR_timerfd_gettime
+# undef __NR_utimensat
diff --git a/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h b/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h
new file mode 100644
index 000000000000..296f3197ee31
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/jmp_buf-macros.h
@@ -0,0 +1,6 @@ 
+#define JMP_BUF_SIZE		(32 + 1 + 64 / (8 * sizeof (unsigned long int))) * sizeof (unsigned long int)
+#define SIGJMP_BUF_SIZE		(32 + 1 + 64 / (8 * sizeof (unsigned long int))) * sizeof (unsigned long int)
+#define JMP_BUF_ALIGN		__alignof__ (unsigned long int)
+#define SIGJMP_BUF_ALIGN	__alignof__ (unsigned long int)
+#define MASK_WAS_SAVED_OFFSET	(32 * sizeof (unsigned long int))
+#define SAVED_MASK_OFFSET	(33 * sizeof (unsigned long int))
diff --git a/sysdeps/unix/sysv/linux/arc/kernel-features.h b/sysdeps/unix/sysv/linux/arc/kernel-features.h
new file mode 100644
index 000000000000..0a5c9e21fbf2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/kernel-features.h
@@ -0,0 +1,27 @@ 
+/* Set flags signalling availability of kernel features based on given
+   kernel version number.
+
+   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/>.  */
+
+/* The minimum supported kernel version for ARC is 5.1 (64-bit time, offsets),
+   although the asm-generic ABI is from 3.9 (when Linux port was merged).  */
+
+#include_next <kernel-features.h>
+
+#undef __ASSUME_CLONE_DEFAULT
+#define __ASSUME_CLONE_BACKWARDS 1
diff --git a/sysdeps/unix/sysv/linux/arc/kernel_stat.h b/sysdeps/unix/sysv/linux/arc/kernel_stat.h
new file mode 100644
index 000000000000..8fdd86b9e843
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/kernel_stat.h
@@ -0,0 +1,26 @@ 
+/* 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 <bits/wordsize.h>
+
+/* Needed to elide the itemized copy code in common xstatconv.c.  */
+#define STAT_IS_KERNEL_STAT 1
+
+/* Nice side-effect of 64-bit time_t switch is these are same.  */
+#define XSTAT_IS_XSTAT64 1
+
+#define STATFS_IS_STATFS64 0
diff --git a/sysdeps/unix/sysv/linux/arc/mmap_internal.h b/sysdeps/unix/sysv/linux/arc/mmap_internal.h
new file mode 100644
index 000000000000..5293d670adaa
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/mmap_internal.h
@@ -0,0 +1,27 @@ 
+/* mmap - map files or devices into memory.  Linux/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 MMAP_ARC_INTERNAL_H
+#define MMAP_ARC_INTERNAL_H
+
+/* 8K is default but determine the shift dynamically with getpagesize.  */
+#define MMAP2_PAGE_UNIT -1
+
+#include_next <mmap_internal.h>
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/arc/sigaction.c b/sysdeps/unix/sysv/linux/arc/sigaction.c
new file mode 100644
index 000000000000..dd590ecb6dd7
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sigaction.c
@@ -0,0 +1,31 @@ 
+/* ARC specific sigaction.
+   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/>.  */
+
+#define SA_RESTORER	0x04000000
+
+extern void __default_rt_sa_restorer (void);
+
+#define SET_SA_RESTORER(kact, act)				\
+ ({								\
+   (kact)->sa_restorer = __default_rt_sa_restorer;		\
+   (kact)->sa_flags |= SA_RESTORER;				\
+ })
+
+#define RESET_SA_RESTORER(act, kact)
+
+#include <sysdeps/unix/sysv/linux/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/arc/sigrestorer.S b/sysdeps/unix/sysv/linux/arc/sigrestorer.S
new file mode 100644
index 000000000000..eaabef505ec2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sigrestorer.S
@@ -0,0 +1,29 @@ 
+/* Default sigreturn stub for ARC Linux.
+   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 <sys/syscall.h>
+#include <sysdep.h>
+#include <tcb-offsets.h>
+
+/* Note the NOP has to be outside body.  */
+	nop
+ENTRY (__default_rt_sa_restorer)
+	mov r8, __NR_rt_sigreturn
+	ARC_TRAP_INSN
+	j_s     [blink]
+PSEUDO_END_NOERRNO (__default_rt_sa_restorer)
diff --git a/sysdeps/unix/sysv/linux/arc/syscall.S b/sysdeps/unix/sysv/linux/arc/syscall.S
new file mode 100644
index 000000000000..6227dbf49917
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/syscall.S
@@ -0,0 +1,33 @@ 
+/* syscall - indirect system call.
+   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 <sysdep.h>
+
+ENTRY (syscall)
+	mov_s	r8, r0
+	mov_s	r0, r1
+	mov_s	r1, r2
+	mov_s	r2, r3
+	mov_s	r3, r4
+	mov_s	r4, r5
+	mov_s	r5, r6
+
+	ARC_TRAP_INSN
+	brhi	r0, -4096, L (call_syscall_err)
+	j	[blink]
+PSEUDO_END (syscall)
diff --git a/sysdeps/unix/sysv/linux/arc/syscalls.list b/sysdeps/unix/sysv/linux/arc/syscalls.list
new file mode 100644
index 000000000000..d0ef5977ee06
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/syscalls.list
@@ -0,0 +1,3 @@ 
+# File name	Caller	Syscall name	Args	Strong name	Weak names
+
+cacheflush	-	cacheflush	i:pii	_flush_cache	cacheflush
diff --git a/sysdeps/unix/sysv/linux/arc/sysdep.c b/sysdeps/unix/sysv/linux/arc/sysdep.c
new file mode 100644
index 000000000000..f33d64679886
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sysdep.c
@@ -0,0 +1,33 @@ 
+/* ARC wrapper for setting errno.
+   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 <sysdep.h>
+#include <errno.h>
+
+/* All syscall handlers land here to avoid generated code bloat due to
+   GOT reference  to errno_location or it's equivalent.  */
+long int
+__syscall_error (long int err_no)
+{
+  __set_errno (-err_no);
+  return -1;
+}
+
+#if IS_IN (libc)
+hidden_def (__syscall_error)
+#endif
diff --git a/sysdeps/unix/sysv/linux/arc/sysdep.h b/sysdeps/unix/sysv/linux/arc/sysdep.h
new file mode 100644
index 000000000000..54d7ede75600
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/sysdep.h
@@ -0,0 +1,224 @@ 
+/* Assembler macros 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/>.  */
+
+#ifndef _LINUX_ARC_SYSDEP_H
+#define _LINUX_ARC_SYSDEP_H 1
+
+#include <sysdeps/arc/sysdep.h>
+#include <sysdeps/unix/sysv/linux/generic/sysdep.h>
+
+/* 32-bit time syscalls are not available, but the redefines allow generic
+   wrappers to work.  */
+#define __NR_clock_adjtime	__NR_clock_adjtime64
+#define __NR_clock_getres	__NR_clock_getres_time64
+#define __NR_futex		__NR_futex_time64
+#define __NR_mq_timedreceive	__NR_mq_timedreceive_time64
+#define __NR_mq_timedsend	__NR_mq_timedsend_time64
+#define __NR_ppoll		__NR_ppoll_time64
+#define __NR_pselect6		__NR_pselect6_time64
+#define __NR_recvmmsg		__NR_recvmmsg_time64
+#define __NR_rt_sigtimedwait	__NR_rt_sigtimedwait_time64
+#define __NR_sched_rr_get_interval	__NR_sched_rr_get_interval_time64
+#define __NR_semtimedop		__NR_semtimedop_time64
+#define __NR_timerfd_gettime	__NR_timerfd_gettime64
+#define __NR_timerfd_settime	__NR_timerfd_settime64
+#define __NR_utimensat		__NR_utimensat_time64
+
+/* For RTLD_PRIVATE_ERRNO.  */
+#include <dl-sysdep.h>
+
+#include <tls.h>
+
+#undef SYS_ify
+#define SYS_ify(syscall_name)   __NR_##syscall_name
+
+#ifdef __ASSEMBLER__
+
+/* This is a "normal" system call stub: if there is an error,
+   it returns -1 and sets errno.  */
+
+# undef PSEUDO
+# define PSEUDO(name, syscall_name, args)			\
+  PSEUDO_NOERRNO(name, syscall_name, args)	ASM_LINE_SEP	\
+    brhi   r0, -4096, L (call_syscall_err)	ASM_LINE_SEP
+
+# define ret	j_s  [blink]
+
+# undef PSEUDO_END
+# define PSEUDO_END(name)					\
+  SYSCALL_ERROR_HANDLER				ASM_LINE_SEP	\
+  END (name)
+
+/* --------- Helper for SYSCALL_NOERRNO -----------
+   This kind of system call stub never returns an error.
+   We return the return value register to the caller unexamined.  */
+
+# undef PSEUDO_NOERRNO
+# define PSEUDO_NOERRNO(name, syscall_name, args)		\
+  .text						ASM_LINE_SEP	\
+  ENTRY (name)					ASM_LINE_SEP	\
+    DO_CALL (syscall_name, args)		ASM_LINE_SEP	\
+
+/* Return the return value register unexamined. Since r0 is both
+   syscall return reg and function return reg, no work needed.  */
+# define ret_NOERRNO						\
+  j_s  [blink]		ASM_LINE_SEP
+
+# undef PSEUDO_END_NOERRNO
+# define PSEUDO_END_NOERRNO(name)				\
+  END (name)
+
+/* --------- Helper for SYSCALL_ERRVAL -----------
+   This kind of system call stub returns the errno code as its return
+   value, or zero for success.  We may massage the kernel's return value
+   to meet that ABI, but we never set errno here.  */
+
+# undef PSEUDO_ERRVAL
+# define PSEUDO_ERRVAL(name, syscall_name, args)		\
+  PSEUDO_NOERRNO(name, syscall_name, args)	ASM_LINE_SEP
+
+/* Don't set errno, return kernel error (in errno form) or zero.  */
+# define ret_ERRVAL						\
+  rsub   r0, r0, 0				ASM_LINE_SEP	\
+  ret_NOERRNO
+
+# undef PSEUDO_END_ERRVAL
+# define PSEUDO_END_ERRVAL(name)				\
+  END (name)
+
+
+/* To reduce the code footprint, we confine the actual errno access
+   to single place in __syscall_error().
+   This takes raw kernel error value, sets errno and returns -1.  */
+# if IS_IN (libc)
+#  define CALL_ERRNO_SETTER_C	bl     PLTJMP(HIDDEN_JUMPTARGET(__syscall_error))
+# else
+#  define CALL_ERRNO_SETTER_C	bl     PLTJMP(__syscall_error)
+# endif
+
+# define SYSCALL_ERROR_HANDLER				\
+L (call_syscall_err):			ASM_LINE_SEP	\
+    push_s   blink			ASM_LINE_SEP	\
+    cfi_adjust_cfa_offset (4)		ASM_LINE_SEP	\
+    cfi_rel_offset (blink, 0)		ASM_LINE_SEP	\
+    CALL_ERRNO_SETTER_C			ASM_LINE_SEP	\
+    pop_s  blink			ASM_LINE_SEP	\
+    cfi_adjust_cfa_offset (-4)		ASM_LINE_SEP	\
+    cfi_restore (blink)			ASM_LINE_SEP	\
+    j_s      [blink]
+
+# define DO_CALL(syscall_name, args)				\
+    mov    r8, SYS_ify (syscall_name)	ASM_LINE_SEP	\
+    ARC_TRAP_INSN			ASM_LINE_SEP
+
+# define ARC_TRAP_INSN	trap_s 0
+
+#else  /* !__ASSEMBLER__ */
+
+# define SINGLE_THREAD_BY_GLOBAL		1
+
+# if IS_IN (libc)
+extern long int __syscall_error (long int);
+hidden_proto (__syscall_error)
+# endif
+
+# define ARC_TRAP_INSN	"trap_s 0	\n\t"
+
+# undef INTERNAL_SYSCALL_NCS
+# define INTERNAL_SYSCALL_NCS(number, nr_args, args...)	\
+  ({								\
+    /* Per ABI, r0 is 1st arg and return reg.  */		\
+    register long int __ret __asm__("r0");			\
+    register long int _sys_num __asm__("r8");			\
+								\
+    LOAD_ARGS_##nr_args (number, args)				\
+								\
+    __asm__ volatile (						\
+                      ARC_TRAP_INSN				\
+                      : "+r" (__ret)				\
+                      : "r"(_sys_num) ASM_ARGS_##nr_args	\
+                      : "memory");				\
+                                                                \
+    __ret; })
+
+# undef INTERNAL_SYSCALL
+# define INTERNAL_SYSCALL(name, nr, args...) 	\
+  INTERNAL_SYSCALL_NCS(SYS_ify(name), nr, args)
+
+/* Macros for setting up inline __asm__ input regs.  */
+# define ASM_ARGS_0
+# define ASM_ARGS_1	ASM_ARGS_0, "r" (__ret)
+# define ASM_ARGS_2	ASM_ARGS_1, "r" (_arg2)
+# define ASM_ARGS_3	ASM_ARGS_2, "r" (_arg3)
+# define ASM_ARGS_4	ASM_ARGS_3, "r" (_arg4)
+# define ASM_ARGS_5	ASM_ARGS_4, "r" (_arg5)
+# define ASM_ARGS_6	ASM_ARGS_5, "r" (_arg6)
+# define ASM_ARGS_7	ASM_ARGS_6, "r" (_arg7)
+
+/* Macros for converting sys-call wrapper args into sys call args.  */
+# define LOAD_ARGS_0(nm, arg)				\
+  _sys_num = (long int) (nm);
+
+# define LOAD_ARGS_1(nm, arg1)				\
+  __ret = (long int) (arg1);					\
+  LOAD_ARGS_0 (nm, arg1)
+
+/* Note that the use of _tmpX might look superflous, however it is needed
+   to ensure that register variables are not clobbered if arg happens to be
+   a function call itself. e.g. sched_setaffinity() calling getpid() for arg2
+   Also this specific order of recursive calling is important to segregate
+   the tmp args evaluation (function call case described above) and assigment
+   of register variables.  */
+
+# define LOAD_ARGS_2(nm, arg1, arg2)			\
+  long int _tmp2 = (long int) (arg2);			\
+  LOAD_ARGS_1 (nm, arg1)				\
+  register long int _arg2 __asm__ ("r1") = _tmp2;
+
+# define LOAD_ARGS_3(nm, arg1, arg2, arg3)		\
+  long int _tmp3 = (long int) (arg3);			\
+  LOAD_ARGS_2 (nm, arg1, arg2)				\
+  register long int _arg3 __asm__ ("r2") = _tmp3;
+
+#define LOAD_ARGS_4(nm, arg1, arg2, arg3, arg4)		\
+  long int _tmp4 = (long int) (arg4);			\
+  LOAD_ARGS_3 (nm, arg1, arg2, arg3)			\
+  register long int _arg4 __asm__ ("r3") = _tmp4;
+
+# define LOAD_ARGS_5(nm, arg1, arg2, arg3, arg4, arg5)	\
+  long int _tmp5 = (long int) (arg5);			\
+  LOAD_ARGS_4 (nm, arg1, arg2, arg3, arg4)		\
+  register long int _arg5 __asm__ ("r4") = _tmp5;
+
+# define LOAD_ARGS_6(nm,  arg1, arg2, arg3, arg4, arg5, arg6)\
+  long int _tmp6 = (long int) (arg6);			\
+  LOAD_ARGS_5 (nm, arg1, arg2, arg3, arg4, arg5)	\
+  register long int _arg6 __asm__ ("r5") = _tmp6;
+
+# define LOAD_ARGS_7(nm, arg1, arg2, arg3, arg4, arg5, arg6, arg7)\
+  long int _tmp7 = (int) (arg7);				\
+  LOAD_ARGS_6 (nm, arg1, arg2, arg3, arg4, arg5, arg6)	\
+  register long int _arg7 __asm__ ("r6") = _tmp7;
+
+/* Pointer mangling not yet supported.  */
+# define PTR_MANGLE(var) (void) (var)
+# define PTR_DEMANGLE(var) (void) (var)
+
+#endif /* !__ASSEMBLER__ */
+
+#endif /* linux/arc/sysdep.h */
diff --git a/sysdeps/unix/sysv/linux/arc/vfork.S b/sysdeps/unix/sysv/linux/arc/vfork.S
new file mode 100644
index 000000000000..c2ebdd9b6203
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/arc/vfork.S
@@ -0,0 +1,42 @@ 
+/* vfork for ARC Linux.
+   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 <sys/syscall.h>
+#include <sysdep.h>
+#include <tcb-offsets.h>
+#define _SIGNAL_H
+#include <bits/signum.h>       /* For SIGCHLD */
+
+#define CLONE_VM		0x00000100
+#define CLONE_VFORK		0x00004000
+#define CLONE_FLAGS_FOR_VFORK	(CLONE_VM|CLONE_VFORK|SIGCHLD)
+
+ENTRY (__vfork)
+	mov	r0, CLONE_FLAGS_FOR_VFORK
+	mov_s	r1, sp
+	mov	r8, __NR_clone
+	ARC_TRAP_INSN
+
+	cmp	r0, 0
+	jge	[blink]	; child continues
+
+	b   __syscall_error
+PSEUDO_END (__vfork)
+libc_hidden_def (__vfork)
+
+weak_alias (__vfork, vfork)