sh: add system call table generation support

The system call tables are in different format in all
architecture and it will be difficult to manually add,
modify or delete the syscall table entries in the res-
pective files. To make it easy by keeping a script and
which will generate the uapi header and syscall table
file. This change will also help to unify the implemen-
tation across all architectures.

The system call table generation script is added in
kernel/syscalls directory which contain the scripts to
generate both uapi header file and system call table
files. The syscall.tbl will be input for the scripts.

syscall.tbl contains the list of available system calls
along with system call number and corresponding entry
point. Add a new system call in this architecture will
be possible by adding new entry in the syscall.tbl file.

Adding a new table entry consisting of:
  	- System call number.
	- ABI.
	- System call name.
	- Entry point name.

syscallhdr.sh and syscalltbl.sh will generate uapi header
unistd_32.h and syscall_table.h files respectively. Both
.sh files will parse the content syscall.tbl to generate
the header and table files. unistd_32.h will be included
by uapi/asm/unistd.h and syscall_table.h is included by
kernel/syscall_32.S - the real system call table.

Please note, this support is only available for 32-bit
kernel, not 64-bit kernel. As I came across the 64-bit
kernel is not active for long time.

ARM, s390 and x86 architecuture does have similar support.
I leverage their implementation to come up with a generic
solution.
Signed-off-by: Firoz Khan <firoz.khan@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/sh/kernel/syscalls/Makefile

+# SPDX-License-Identifier: GPL-2.0
+kapi := arch/$(SRCARCH)/include/generated/asm
+uapi := arch/$(SRCARCH)/include/generated/uapi/asm
+
+_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
+	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+
+syscall := $(srctree)/$(src)/syscall.tbl
+syshdr := $(srctree)/$(src)/syscallhdr.sh
+systbl := $(srctree)/$(src)/syscalltbl.sh
+
+quiet_cmd_syshdr = SYSHDR  $@
+      cmd_syshdr = $(CONFIG_SHELL) '$(syshdr)' '$<' '$@'	\
+		   '$(syshdr_abis_$(basetarget))'		\
+		   '$(syshdr_pfx_$(basetarget))'		\
+		   '$(syshdr_offset_$(basetarget))'
+
+quiet_cmd_systbl = SYSTBL  $@
+      cmd_systbl = $(CONFIG_SHELL) '$(systbl)' '$<' '$@'	\
+		   '$(systbl_abis_$(basetarget))'		\
+		   '$(systbl_abi_$(basetarget))'		\
+		   '$(systbl_offset_$(basetarget))'
+
+$(uapi)/unistd_32.h: $(syscall) $(syshdr)
+	$(call if_changed,syshdr)
+
+$(kapi)/syscall_table.h: $(syscall) $(systbl)
+	$(call if_changed,systbl)
+
+uapisyshdr-y		+= unistd_32.h
+kapisyshdr-y		+= syscall_table.h
+
+targets	+= $(uapisyshdr-y) $(kapisyshdr-y)
+
+PHONY += all
+all: $(addprefix $(uapi)/,$(uapisyshdr-y))
+all: $(addprefix $(kapi)/,$(kapisyshdr-y))
+	@:

arch/sh/kernel/syscalls/syscall.tbl

+# SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+#
+# system call numbers and entry vectors for sh
+#
+# The format is:
+# <number> <abi> <name> <entry point>
+#
+# The <abi> is always "common" for this file
+#
+0	common	restart_syscall			sys_restart_syscall
+1	common	exit				sys_exit
+2	common	fork				sys_fork
+3	common	read				sys_read
+4	common	write				sys_write
+5	common	open				sys_open
+6	common	close				sys_close
+7	common	waitpid				sys_waitpid
+8	common	creat				sys_creat
+9	common	link				sys_link
+10	common	unlink				sys_unlink
+11	common	execve				sys_execve
+12	common	chdir				sys_chdir
+13	common	time				sys_time
+14	common	mknod				sys_mknod
+15	common	chmod				sys_chmod
+16	common	lchown				sys_lchown16
+# 17 was break
+18	common	oldstat				sys_stat
+19	common	lseek				sys_lseek
+20	common	getpid				sys_getpid
+21	common	mount				sys_mount
+22	common	umount				sys_oldumount
+23	common	setuid				sys_setuid16
+24	common	getuid				sys_getuid16
+25	common	stime				sys_stime
+26	common	ptrace				sys_ptrace
+27	common	alarm				sys_alarm
+28	common	oldfstat			sys_fstat
+29	common	pause				sys_pause
+30	common	utime				sys_utime
+# 31 was stty
+# 32 was gtty
+33	common	access				sys_access
+34	common	nice				sys_nice
+# 35 was ftime
+36	common	sync				sys_sync
+37	common	kill				sys_kill
+38	common	rename				sys_rename
+39	common	mkdir				sys_mkdir
+40	common	rmdir				sys_rmdir
+41	common	dup				sys_dup
+42	common	pipe				sys_sh_pipe
+43	common	times				sys_times
+# 44 was prof
+45	common	brk				sys_brk
+46	common	setgid				sys_setgid16
+47	common	getgid				sys_getgid16
+48	common	signal				sys_signal
+49	common	geteuid				sys_geteuid16
+50	common	getegid				sys_getegid16
+51	common	acct				sys_acct
+52	common	umount2				sys_umount
+# 53 was lock
+54	common	ioctl				sys_ioctl
+55	common	fcntl				sys_fcntl
+# 56 was mpx
+57	common	setpgid				sys_setpgid
+# 58 was ulimit
+# 59 was olduname
+60	common	umask				sys_umask
+61	common	chroot				sys_chroot
+62	common	ustat				sys_ustat
+63	common	dup2				sys_dup2
+64	common	getppid				sys_getppid
+65	common	getpgrp				sys_getpgrp
+66	common	setsid				sys_setsid
+67	common	sigaction			sys_sigaction
+68	common	sgetmask			sys_sgetmask
+69	common	ssetmask			sys_ssetmask
+70	common	setreuid			sys_setreuid16
+71	common	setregid			sys_setregid16
+72	common	sigsuspend			sys_sigsuspend
+73	common	sigpending			sys_sigpending
+74	common	sethostname			sys_sethostname
+75	common	setrlimit			sys_setrlimit
+76	common	getrlimit			sys_old_getrlimit
+77	common	getrusage			sys_getrusage
+78	common	gettimeofday			sys_gettimeofday
+79	common	settimeofday			sys_settimeofday
+80	common	getgroups			sys_getgroups16
+81	common	setgroups			sys_setgroups16
+# 82 was select
+83	common	symlink				sys_symlink
+84	common	oldlstat			sys_lstat
+85	common	readlink			sys_readlink
+86	common	uselib				sys_uselib
+87	common	swapon				sys_swapon
+88	common	reboot				sys_reboot
+89	common	readdir				sys_old_readdir
+90	common	mmap				old_mmap
+91	common	munmap				sys_munmap
+92	common	truncate			sys_truncate
+93	common	ftruncate			sys_ftruncate
+94	common	fchmod				sys_fchmod
+95	common	fchown				sys_fchown16
+96	common	getpriority			sys_getpriority
+97	common	setpriority			sys_setpriority
+# 98 was profil
+99	common	statfs				sys_statfs
+100	common	fstatfs				sys_fstatfs
+# 101 was ioperm
+102	common	socketcall			sys_socketcall
+103	common	syslog				sys_syslog
+104	common	setitimer			sys_setitimer
+105	common	getitimer			sys_getitimer
+106	common	stat				sys_newstat
+107	common	lstat				sys_newlstat
+108	common	fstat				sys_newfstat
+109	common	olduname			sys_uname
+# 110 was iopl
+111	common	vhangup				sys_vhangup
+# 112 was idle
+# 113 was vm86old
+114	common	wait4				sys_wait4
+115	common	swapoff				sys_swapoff
+116	common	sysinfo				sys_sysinfo
+117	common	ipc				sys_ipc
+118	common	fsync				sys_fsync
+119	common	sigreturn			sys_sigreturn
+120	common	clone				sys_clone
+121	common	setdomainname			sys_setdomainname
+122	common	uname				sys_newuname
+123	common	cacheflush			sys_cacheflush
+124	common	adjtimex			sys_adjtimex
+125	common	mprotect			sys_mprotect
+126	common	sigprocmask			sys_sigprocmask
+# 127 was create_module
+128	common	init_module			sys_init_module
+129	common	delete_module			sys_delete_module
+# 130 was get_kernel_syms
+131	common	quotactl			sys_quotactl
+132	common	getpgid				sys_getpgid
+133	common	fchdir				sys_fchdir
+134	common	bdflush				sys_bdflush
+135	common	sysfs				sys_sysfs
+136	common	personality			sys_personality
+# 137 was afs_syscall
+138	common	setfsuid			sys_setfsuid16
+139	common	setfsgid			sys_setfsgid16
+140	common	_llseek				sys_llseek
+141	common	getdents			sys_getdents
+142	common	_newselect			sys_select
+143	common	flock				sys_flock
+144	common	msync				sys_msync
+145	common	readv				sys_readv
+146	common	writev				sys_writev
+147	common	getsid				sys_getsid
+148	common	fdatasync			sys_fdatasync
+149	common	_sysctl				sys_sysctl
+150	common	mlock				sys_mlock
+151	common	munlock				sys_munlock
+152	common	mlockall			sys_mlockall
+153	common	munlockall			sys_munlockall
+154	common	sched_setparam			sys_sched_setparam
+155	common	sched_getparam			sys_sched_getparam
+156	common	sched_setscheduler		sys_sched_setscheduler
+157	common	sched_getscheduler		sys_sched_getscheduler
+158	common	sched_yield			sys_sched_yield
+159	common	sched_get_priority_max		sys_sched_get_priority_max
+160	common	sched_get_priority_min		sys_sched_get_priority_min
+161	common	sched_rr_get_interval		sys_sched_rr_get_interval
+162	common	nanosleep			sys_nanosleep
+163	common	mremap				sys_mremap
+164	common	setresuid			sys_setresuid16
+165	common	getresuid			sys_getresuid16
+# 166 was vm86
+# 167 was query_module
+168	common	poll				sys_poll
+169	common	nfsservctl			sys_ni_syscall
+170	common	setresgid			sys_setresgid16
+171	common	getresgid			sys_getresgid16
+172	common	prctl				sys_prctl
+173	common	rt_sigreturn			sys_rt_sigreturn
+174	common	rt_sigaction			sys_rt_sigaction
+175	common	rt_sigprocmask			sys_rt_sigprocmask
+176	common	rt_sigpending			sys_rt_sigpending
+177	common	rt_sigtimedwait			sys_rt_sigtimedwait
+178	common	rt_sigqueueinfo			sys_rt_sigqueueinfo
+179	common	rt_sigsuspend			sys_rt_sigsuspend
+180	common	pread64				sys_pread_wrapper
+181	common	pwrite64			sys_pwrite_wrapper
+182	common	chown				sys_chown16
+183	common	getcwd				sys_getcwd
+184	common	capget				sys_capget
+185	common	capset				sys_capset
+186	common	sigaltstack			sys_sigaltstack
+187	common	sendfile			sys_sendfile
+# 188 is reserved for getpmsg
+# 189 is reserved for putpmsg
+190	common	vfork				sys_vfork
+191	common	ugetrlimit			sys_getrlimit
+192	common	mmap2				sys_mmap2
+193	common	truncate64			sys_truncate64
+194	common	ftruncate64			sys_ftruncate64
+195	common	stat64				sys_stat64
+196	common	lstat64				sys_lstat64
+197	common	fstat64				sys_fstat64
+198	common	lchown32			sys_lchown
+199	common	getuid32			sys_getuid
+200	common	getgid32			sys_getgid
+201	common	geteuid32			sys_geteuid
+202	common	getegid32			sys_getegid
+203	common	setreuid32			sys_setreuid
+204	common	setregid32			sys_setregid
+205	common	getgroups32			sys_getgroups
+206	common	setgroups32			sys_setgroups
+207	common	fchown32			sys_fchown
+208	common	setresuid32			sys_setresuid
+209	common	getresuid32			sys_getresuid
+210	common	setresgid32			sys_setresgid
+211	common	getresgid32			sys_getresgid
+212	common	chown32				sys_chown
+213	common	setuid32			sys_setuid
+214	common	setgid32			sys_setgid
+215	common	setfsuid32			sys_setfsuid
+216	common	setfsgid32			sys_setfsgid
+217	common	pivot_root			sys_pivot_root
+218	common	mincore				sys_mincore
+219	common	madvise				sys_madvise
+220	common	getdents64			sys_getdents64
+221	common	fcntl64				sys_fcntl64
+# 222 is reserved for tux
+# 223 is unused
+224	common	gettid				sys_gettid
+225	common	readahead			sys_readahead
+226	common	setxattr			sys_setxattr
+227	common	lsetxattr			sys_lsetxattr
+228	common	fsetxattr			sys_fsetxattr
+229	common	getxattr			sys_getxattr
+230	common	lgetxattr			sys_lgetxattr
+231	common	fgetxattr			sys_fgetxattr
+232	common	listxattr			sys_listxattr
+233	common	llistxattr			sys_llistxattr
+234	common	flistxattr			sys_flistxattr
+235	common	removexattr			sys_removexattr
+236	common	lremovexattr			sys_lremovexattr
+237	common	fremovexattr			sys_fremovexattr
+238	common	tkill				sys_tkill
+239	common	sendfile64			sys_sendfile64
+240	common	futex				sys_futex
+241	common	sched_setaffinity		sys_sched_setaffinity
+242	common	sched_getaffinity		sys_sched_getaffinity
+# 243 is reserved for set_thread_area
+# 244 is reserved for get_thread_area
+245	common	io_setup			sys_io_setup
+246	common	io_destroy			sys_io_destroy
+247	common	io_getevents			sys_io_getevents
+248	common	io_submit			sys_io_submit
+249	common	io_cancel			sys_io_cancel
+250	common	fadvise64			sys_fadvise64
+# 251 is unused
+252	common	exit_group			sys_exit_group
+253	common	lookup_dcookie			sys_lookup_dcookie
+254	common	epoll_create			sys_epoll_create
+255	common	epoll_ctl			sys_epoll_ctl
+256	common	epoll_wait			sys_epoll_wait
+257	common	remap_file_pages		sys_remap_file_pages
+258	common	set_tid_address			sys_set_tid_address
+259	common	timer_create			sys_timer_create
+260	common	timer_settime			sys_timer_settime
+261	common	timer_gettime			sys_timer_gettime
+262	common	timer_getoverrun		sys_timer_getoverrun
+263	common	timer_delete			sys_timer_delete
+264	common	clock_settime			sys_clock_settime
+265	common	clock_gettime			sys_clock_gettime
+266	common	clock_getres			sys_clock_getres
+267	common	clock_nanosleep			sys_clock_nanosleep
+268	common	statfs64			sys_statfs64
+269	common	fstatfs64			sys_fstatfs64
+270	common	tgkill				sys_tgkill
+271	common	utimes				sys_utimes
+272	common	fadvise64_64			sys_fadvise64_64_wrapper
+# 273 is reserved for vserver
+274	common	mbind				sys_mbind
+275	common	get_mempolicy			sys_get_mempolicy
+276	common	set_mempolicy			sys_set_mempolicy
+277	common	mq_open				sys_mq_open
+278	common	mq_unlink			sys_mq_unlink
+279	common	mq_timedsend			sys_mq_timedsend
+280	common	mq_timedreceive			sys_mq_timedreceive
+281	common	mq_notify			sys_mq_notify
+282	common	mq_getsetattr			sys_mq_getsetattr
+283	common	kexec_load			sys_kexec_load
+284	common	waitid				sys_waitid
+285	common	add_key				sys_add_key
+286	common	request_key			sys_request_key
+287	common	keyctl				sys_keyctl
+288	common	ioprio_set			sys_ioprio_set
+289	common	ioprio_get			sys_ioprio_get
+290	common	inotify_init			sys_inotify_init
+291	common	inotify_add_watch		sys_inotify_add_watch
+292	common	inotify_rm_watch		sys_inotify_rm_watch
+# 293 is unused
+294	common	migrate_pages			sys_migrate_pages
+295	common	openat				sys_openat
+296	common	mkdirat				sys_mkdirat
+297	common	mknodat				sys_mknodat
+298	common	fchownat			sys_fchownat
+299	common	futimesat			sys_futimesat
+300	common	fstatat64			sys_fstatat64
+301	common	unlinkat			sys_unlinkat
+302	common	renameat			sys_renameat
+303	common	linkat				sys_linkat
+304	common	symlinkat			sys_symlinkat
+305	common	readlinkat			sys_readlinkat
+306	common	fchmodat			sys_fchmodat
+307	common	faccessat			sys_faccessat
+308	common	pselect6			sys_pselect6
+309	common	ppoll				sys_ppoll
+310	common	unshare				sys_unshare
+311	common	set_robust_list			sys_set_robust_list
+312	common	get_robust_list			sys_get_robust_list
+313	common	splice				sys_splice
+314	common	sync_file_range			sys_sync_file_range
+315	common	tee				sys_tee
+316	common	vmsplice			sys_vmsplice
+317	common	move_pages			sys_move_pages
+318	common	getcpu				sys_getcpu
+319	common	epoll_pwait			sys_epoll_pwait
+320	common	utimensat			sys_utimensat
+321	common	signalfd			sys_signalfd
+322	common	timerfd_create			sys_timerfd_create
+323	common	eventfd				sys_eventfd
+324	common	fallocate			sys_fallocate
+325	common	timerfd_settime			sys_timerfd_settime
+326	common	timerfd_gettime			sys_timerfd_gettime
+327	common	signalfd4			sys_signalfd4
+328	common	eventfd2			sys_eventfd2
+329	common	epoll_create1			sys_epoll_create1
+330	common	dup3				sys_dup3
+331	common	pipe2				sys_pipe2
+332	common	inotify_init1			sys_inotify_init1
+333	common	preadv				sys_preadv
+334	common	pwritev				sys_pwritev
+335	common	rt_tgsigqueueinfo		sys_rt_tgsigqueueinfo
+336	common	perf_event_open			sys_perf_event_open
+337	common	fanotify_init			sys_fanotify_init
+338	common	fanotify_mark			sys_fanotify_mark
+339	common	prlimit64			sys_prlimit64
+340	common	socket				sys_socket
+341	common	bind				sys_bind
+342	common	connect				sys_connect
+343	common	listen				sys_listen
+344	common	accept				sys_accept
+345	common	getsockname			sys_getsockname
+346	common	getpeername			sys_getpeername
+347	common	socketpair			sys_socketpair
+348	common	send				sys_send
+349	common	sendto				sys_sendto
+350	common	recv				sys_recv
+351	common	recvfrom			sys_recvfrom
+352	common	shutdown			sys_shutdown
+353	common	setsockopt			sys_setsockopt
+354	common	getsockopt			sys_getsockopt
+355	common	sendmsg				sys_sendmsg
+356	common	recvmsg				sys_recvmsg
+357	common	recvmmsg			sys_recvmmsg
+358	common	accept4				sys_accept4
+359	common	name_to_handle_at		sys_name_to_handle_at
+360	common	open_by_handle_at		sys_open_by_handle_at
+361	common	clock_adjtime			sys_clock_adjtime
+362	common	syncfs				sys_syncfs
+363	common	sendmmsg			sys_sendmmsg
+364	common	setns				sys_setns
+365	common	process_vm_readv		sys_process_vm_readv
+366	common	process_vm_writev		sys_process_vm_writev
+367	common	kcmp				sys_kcmp
+368	common	finit_module			sys_finit_module
+369	common	sched_getattr			sys_sched_getattr
+370	common	sched_setattr			sys_sched_setattr
+371	common	renameat2			sys_renameat2
+372	common	seccomp				sys_seccomp
+373	common	getrandom			sys_getrandom
+374	common	memfd_create			sys_memfd_create
+375	common	bpf				sys_bpf
+376	common	execveat			sys_execveat
+377	common	userfaultfd			sys_userfaultfd
+378	common	membarrier			sys_membarrier
+379	common	mlock2				sys_mlock2
+380	common	copy_file_range			sys_copy_file_range
+381	common	preadv2				sys_preadv2
+382	common	pwritev2			sys_pwritev2

arch/sh/kernel/syscalls/syscallhdr.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+in="$1"
+out="$2"
+my_abis=`echo "($3)" | tr ',' '|'`
+prefix="$4"
+offset="$5"
+
+fileguard=_UAPI_ASM_SH_`basename "$out" | sed \
+	-e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
+	-e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g'`
+grep -E "^[0-9A-Fa-fXx]+[[:space:]]+${my_abis}" "$in" | sort -n | (
+	printf "#ifndef %s\n" "${fileguard}"
+	printf "#define %s\n" "${fileguard}"
+	printf "\n"
+
+	nxt=0
+	while read nr abi name entry ; do
+		if [ -z "$offset" ]; then
+			printf "#define __NR_%s%s\t%s\n" \
+				"${prefix}" "${name}" "${nr}"
+		else
+			printf "#define __NR_%s%s\t(%s + %s)\n" \
+				"${prefix}" "${name}" "${offset}" "${nr}"
+		fi
+		nxt=$((nr+1))
+	done
+
+	printf "\n"
+	printf "#ifdef __KERNEL__\n"
+	printf "#define __NR_syscalls\t%s\n" "${nxt}"
+	printf "#endif\n"
+	printf "\n"
+	printf "#endif /* %s */" "${fileguard}"
+) > "$out"

arch/sh/kernel/syscalls/syscalltbl.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+in="$1"
+out="$2"
+my_abis=`echo "($3)" | tr ',' '|'`
+my_abi="$4"
+offset="$5"
+
+emit() {
+	t_nxt="$1"
+	t_nr="$2"
+	t_entry="$3"
+
+	while [ $t_nxt -lt $t_nr ]; do
+		printf "__SYSCALL(%s, sys_ni_syscall, )\n" "${t_nxt}"
+		t_nxt=$((t_nxt+1))
+	done
+	printf "__SYSCALL(%s, %s, )\n" "${t_nxt}" "${t_entry}"
+}
+
+grep -E "^[0-9A-Fa-fXx]+[[:space:]]+${my_abis}" "$in" | sort -n | (
+	nxt=0
+	if [ -z "$offset" ]; then
+		offset=0
+	fi
+
+	while read nr abi name entry ; do
+		emit $((nxt+offset)) $((nr+offset)) $entry
+		nxt=$((nr+1))
+	done
+) > "$out"