2 * This file contains the procedures for the handling of select and poll
4 * Created for Linux based loosely upon Mathius Lattner's minix
5 * patches by Peter MacDonald. Heavily edited by Linus.
8 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
9 * flag set in its personality we do *not* modify the given timeout
10 * parameter to reflect time remaining.
13 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
14 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/syscalls.h>
20 #include <linux/export.h>
21 #include <linux/slab.h>
22 #include <linux/poll.h>
23 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
24 #include <linux/file.h>
25 #include <linux/fdtable.h>
27 #include <linux/rcupdate.h>
28 #include <linux/hrtimer.h>
29 #include <linux/sched/rt.h>
30 #include <linux/freezer.h>
31 #include <net/busy_poll.h>
32 #include <linux/vmalloc.h>
34 #include <linux/uaccess.h>
38 * Estimate expected accuracy in ns from a timeval.
40 * After quite a bit of churning around, we've settled on
41 * a simple thing of taking 0.1% of the timeout as the
42 * slack, with a cap of 100 msec.
43 * "nice" tasks get a 0.5% slack instead.
45 * Consider this comment an open invitation to come up with even
49 #define MAX_SLACK (100 * NSEC_PER_MSEC)
51 static long __estimate_accuracy(struct timespec64 *tv)
59 if (task_nice(current) > 0)
60 divfactor = divfactor / 5;
62 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
65 slack = tv->tv_nsec / divfactor;
66 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
68 if (slack > MAX_SLACK)
74 u64 select_estimate_accuracy(struct timespec64 *tv)
77 struct timespec64 now;
80 * Realtime tasks get a slack of 0 for obvious reasons.
87 now = timespec64_sub(*tv, now);
88 ret = __estimate_accuracy(&now);
89 if (ret < current->timer_slack_ns)
90 return current->timer_slack_ns;
96 struct poll_table_page {
97 struct poll_table_page * next;
98 struct poll_table_entry * entry;
99 struct poll_table_entry entries[0];
102 #define POLL_TABLE_FULL(table) \
103 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
106 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
107 * I have rewritten this, taking some shortcuts: This code may not be easy to
108 * follow, but it should be free of race-conditions, and it's practical. If you
109 * understand what I'm doing here, then you understand how the linux
110 * sleep/wakeup mechanism works.
112 * Two very simple procedures, poll_wait() and poll_freewait() make all the
113 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
114 * as all select/poll functions have to call it to add an entry to the
117 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
120 void poll_initwait(struct poll_wqueues *pwq)
122 init_poll_funcptr(&pwq->pt, __pollwait);
123 pwq->polling_task = current;
127 pwq->inline_index = 0;
129 EXPORT_SYMBOL(poll_initwait);
131 static void free_poll_entry(struct poll_table_entry *entry)
133 remove_wait_queue(entry->wait_address, &entry->wait);
137 void poll_freewait(struct poll_wqueues *pwq)
139 struct poll_table_page * p = pwq->table;
141 for (i = 0; i < pwq->inline_index; i++)
142 free_poll_entry(pwq->inline_entries + i);
144 struct poll_table_entry * entry;
145 struct poll_table_page *old;
150 free_poll_entry(entry);
151 } while (entry > p->entries);
154 free_page((unsigned long) old);
157 EXPORT_SYMBOL(poll_freewait);
159 static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
161 struct poll_table_page *table = p->table;
163 if (p->inline_index < N_INLINE_POLL_ENTRIES)
164 return p->inline_entries + p->inline_index++;
166 if (!table || POLL_TABLE_FULL(table)) {
167 struct poll_table_page *new_table;
169 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
174 new_table->entry = new_table->entries;
175 new_table->next = table;
176 p->table = new_table;
180 return table->entry++;
183 static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
185 struct poll_wqueues *pwq = wait->private;
186 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
189 * Although this function is called under waitqueue lock, LOCK
190 * doesn't imply write barrier and the users expect write
191 * barrier semantics on wakeup functions. The following
192 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
193 * and is paired with smp_store_mb() in poll_schedule_timeout.
199 * Perform the default wake up operation using a dummy
202 * TODO: This is hacky but there currently is no interface to
203 * pass in @sync. @sync is scheduled to be removed and once
204 * that happens, wake_up_process() can be used directly.
206 return default_wake_function(&dummy_wait, mode, sync, key);
209 static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
211 struct poll_table_entry *entry;
213 entry = container_of(wait, struct poll_table_entry, wait);
214 if (key && !((unsigned long)key & entry->key))
216 return __pollwake(wait, mode, sync, key);
219 /* Add a new entry */
220 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
223 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
224 struct poll_table_entry *entry = poll_get_entry(pwq);
227 entry->filp = get_file(filp);
228 entry->wait_address = wait_address;
229 entry->key = p->_key;
230 init_waitqueue_func_entry(&entry->wait, pollwake);
231 entry->wait.private = pwq;
232 add_wait_queue(wait_address, &entry->wait);
235 int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
236 ktime_t *expires, unsigned long slack)
240 set_current_state(state);
242 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
243 __set_current_state(TASK_RUNNING);
246 * Prepare for the next iteration.
248 * The following smp_store_mb() serves two purposes. First, it's
249 * the counterpart rmb of the wmb in pollwake() such that data
250 * written before wake up is always visible after wake up.
251 * Second, the full barrier guarantees that triggered clearing
252 * doesn't pass event check of the next iteration. Note that
253 * this problem doesn't exist for the first iteration as
254 * add_wait_queue() has full barrier semantics.
256 smp_store_mb(pwq->triggered, 0);
260 EXPORT_SYMBOL(poll_schedule_timeout);
263 * poll_select_set_timeout - helper function to setup the timeout value
264 * @to: pointer to timespec64 variable for the final timeout
265 * @sec: seconds (from user space)
266 * @nsec: nanoseconds (from user space)
268 * Note, we do not use a timespec for the user space value here, That
269 * way we can use the function for timeval and compat interfaces as well.
271 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
273 int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
275 struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
277 if (!timespec64_valid(&ts))
280 /* Optimize for the zero timeout value here */
282 to->tv_sec = to->tv_nsec = 0;
285 *to = timespec64_add_safe(*to, ts);
290 static int poll_select_copy_remaining(struct timespec64 *end_time,
292 int timeval, int ret)
294 struct timespec64 rts64;
301 if (current->personality & STICKY_TIMEOUTS)
304 /* No update for zero timeout */
305 if (!end_time->tv_sec && !end_time->tv_nsec)
308 ktime_get_ts64(&rts64);
309 rts64 = timespec64_sub(*end_time, rts64);
310 if (rts64.tv_sec < 0)
311 rts64.tv_sec = rts64.tv_nsec = 0;
313 rts = timespec64_to_timespec(rts64);
316 if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
317 memset(&rtv, 0, sizeof(rtv));
318 rtv.tv_sec = rts64.tv_sec;
319 rtv.tv_usec = rts64.tv_nsec / NSEC_PER_USEC;
321 if (!copy_to_user(p, &rtv, sizeof(rtv)))
324 } else if (!copy_to_user(p, &rts, sizeof(rts)))
328 * If an application puts its timeval in read-only memory, we
329 * don't want the Linux-specific update to the timeval to
330 * cause a fault after the select has completed
331 * successfully. However, because we're not updating the
332 * timeval, we can't restart the system call.
336 if (ret == -ERESTARTNOHAND)
341 #define FDS_IN(fds, n) (fds->in + n)
342 #define FDS_OUT(fds, n) (fds->out + n)
343 #define FDS_EX(fds, n) (fds->ex + n)
345 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
347 static int max_select_fd(unsigned long n, fd_set_bits *fds)
349 unsigned long *open_fds;
354 /* handle last in-complete long-word first */
355 set = ~(~0UL << (n & (BITS_PER_LONG-1)));
357 fdt = files_fdtable(current->files);
358 open_fds = fdt->open_fds + n;
363 if (!(set & ~*open_fds))
374 if (set & ~*open_fds)
383 max += n * BITS_PER_LONG;
389 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
390 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
391 #define POLLEX_SET (POLLPRI)
393 static inline void wait_key_set(poll_table *wait, unsigned long in,
394 unsigned long out, unsigned long bit,
395 unsigned int ll_flag)
397 wait->_key = POLLEX_SET | ll_flag;
399 wait->_key |= POLLIN_SET;
401 wait->_key |= POLLOUT_SET;
404 int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
406 ktime_t expire, *to = NULL;
407 struct poll_wqueues table;
409 int retval, i, timed_out = 0;
411 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
412 unsigned long busy_end = 0;
415 retval = max_select_fd(n, fds);
422 poll_initwait(&table);
424 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
429 if (end_time && !timed_out)
430 slack = select_estimate_accuracy(end_time);
434 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
435 bool can_busy_loop = false;
437 inp = fds->in; outp = fds->out; exp = fds->ex;
438 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
440 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
441 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
442 unsigned long res_in = 0, res_out = 0, res_ex = 0;
444 in = *inp++; out = *outp++; ex = *exp++;
445 all_bits = in | out | ex;
451 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
455 if (!(bit & all_bits))
459 const struct file_operations *f_op;
461 mask = DEFAULT_POLLMASK;
463 wait_key_set(wait, in, out,
465 mask = (*f_op->poll)(f.file, wait);
468 if ((mask & POLLIN_SET) && (in & bit)) {
473 if ((mask & POLLOUT_SET) && (out & bit)) {
478 if ((mask & POLLEX_SET) && (ex & bit)) {
483 /* got something, stop busy polling */
485 can_busy_loop = false;
489 * only remember a returned
490 * POLL_BUSY_LOOP if we asked for it
492 } else if (busy_flag & mask)
493 can_busy_loop = true;
506 if (retval || timed_out || signal_pending(current))
509 retval = table.error;
513 /* only if found POLL_BUSY_LOOP sockets && not out of time */
514 if (can_busy_loop && !need_resched()) {
516 busy_end = busy_loop_end_time();
519 if (!busy_loop_timeout(busy_end))
525 * If this is the first loop and we have a timeout
526 * given, then we convert to ktime_t and set the to
527 * pointer to the expiry value.
529 if (end_time && !to) {
530 expire = timespec64_to_ktime(*end_time);
534 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
539 poll_freewait(&table);
545 * We can actually return ERESTARTSYS instead of EINTR, but I'd
546 * like to be certain this leads to no problems. So I return
547 * EINTR just for safety.
549 * Update: ERESTARTSYS breaks at least the xview clock binary, so
550 * I'm trying ERESTARTNOHAND which restart only when you want to.
552 int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
553 fd_set __user *exp, struct timespec64 *end_time)
558 size_t size, alloc_size;
560 /* Allocate small arguments on the stack to save memory and be faster */
561 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
567 /* max_fds can increase, so grab it once to avoid race */
569 fdt = files_fdtable(current->files);
570 max_fds = fdt->max_fds;
576 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
577 * since we used fdset we need to allocate memory in units of
582 if (size > sizeof(stack_fds) / 6) {
583 /* Not enough space in on-stack array; must use kmalloc */
585 if (size > (SIZE_MAX / 6))
588 alloc_size = 6 * size;
589 bits = kmalloc(alloc_size, GFP_KERNEL|__GFP_NOWARN);
590 if (!bits && alloc_size > PAGE_SIZE)
591 bits = vmalloc(alloc_size);
597 fds.out = bits + size;
598 fds.ex = bits + 2*size;
599 fds.res_in = bits + 3*size;
600 fds.res_out = bits + 4*size;
601 fds.res_ex = bits + 5*size;
603 if ((ret = get_fd_set(n, inp, fds.in)) ||
604 (ret = get_fd_set(n, outp, fds.out)) ||
605 (ret = get_fd_set(n, exp, fds.ex)))
607 zero_fd_set(n, fds.res_in);
608 zero_fd_set(n, fds.res_out);
609 zero_fd_set(n, fds.res_ex);
611 ret = do_select(n, &fds, end_time);
616 ret = -ERESTARTNOHAND;
617 if (signal_pending(current))
622 if (set_fd_set(n, inp, fds.res_in) ||
623 set_fd_set(n, outp, fds.res_out) ||
624 set_fd_set(n, exp, fds.res_ex))
628 if (bits != stack_fds)
634 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
635 fd_set __user *, exp, struct timeval __user *, tvp)
637 struct timespec64 end_time, *to = NULL;
642 if (copy_from_user(&tv, tvp, sizeof(tv)))
646 if (poll_select_set_timeout(to,
647 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
648 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
652 ret = core_sys_select(n, inp, outp, exp, to);
653 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
658 static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
659 fd_set __user *exp, struct timespec __user *tsp,
660 const sigset_t __user *sigmask, size_t sigsetsize)
662 sigset_t ksigmask, sigsaved;
664 struct timespec64 ts64, end_time, *to = NULL;
668 if (copy_from_user(&ts, tsp, sizeof(ts)))
670 ts64 = timespec_to_timespec64(ts);
673 if (poll_select_set_timeout(to, ts64.tv_sec, ts64.tv_nsec))
678 /* XXX: Don't preclude handling different sized sigset_t's. */
679 if (sigsetsize != sizeof(sigset_t))
681 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
684 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
685 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
688 ret = core_sys_select(n, inp, outp, exp, to);
689 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
691 if (ret == -ERESTARTNOHAND) {
693 * Don't restore the signal mask yet. Let do_signal() deliver
694 * the signal on the way back to userspace, before the signal
698 memcpy(¤t->saved_sigmask, &sigsaved,
700 set_restore_sigmask();
703 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
709 * Most architectures can't handle 7-argument syscalls. So we provide a
710 * 6-argument version where the sixth argument is a pointer to a structure
711 * which has a pointer to the sigset_t itself followed by a size_t containing
714 SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
715 fd_set __user *, exp, struct timespec __user *, tsp,
718 size_t sigsetsize = 0;
719 sigset_t __user *up = NULL;
722 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
723 || __get_user(up, (sigset_t __user * __user *)sig)
724 || __get_user(sigsetsize,
725 (size_t __user *)(sig+sizeof(void *))))
729 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
732 #ifdef __ARCH_WANT_SYS_OLD_SELECT
733 struct sel_arg_struct {
735 fd_set __user *inp, *outp, *exp;
736 struct timeval __user *tvp;
739 SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
741 struct sel_arg_struct a;
743 if (copy_from_user(&a, arg, sizeof(a)))
745 return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
750 struct poll_list *next;
752 struct pollfd entries[0];
755 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
758 * Fish for pollable events on the pollfd->fd file descriptor. We're only
759 * interested in events matching the pollfd->events mask, and the result
760 * matching that mask is both recorded in pollfd->revents and returned. The
761 * pwait poll_table will be used by the fd-provided poll handler for waiting,
762 * if pwait->_qproc is non-NULL.
764 static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait,
766 unsigned int busy_flag)
774 struct fd f = fdget(fd);
777 mask = DEFAULT_POLLMASK;
778 if (f.file->f_op->poll) {
779 pwait->_key = pollfd->events|POLLERR|POLLHUP;
780 pwait->_key |= busy_flag;
781 mask = f.file->f_op->poll(f.file, pwait);
782 if (mask & busy_flag)
783 *can_busy_poll = true;
785 /* Mask out unneeded events. */
786 mask &= pollfd->events | POLLERR | POLLHUP;
790 pollfd->revents = mask;
795 static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
796 struct timespec64 *end_time)
798 poll_table* pt = &wait->pt;
799 ktime_t expire, *to = NULL;
800 int timed_out = 0, count = 0;
802 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
803 unsigned long busy_end = 0;
805 /* Optimise the no-wait case */
806 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
811 if (end_time && !timed_out)
812 slack = select_estimate_accuracy(end_time);
815 struct poll_list *walk;
816 bool can_busy_loop = false;
818 for (walk = list; walk != NULL; walk = walk->next) {
819 struct pollfd * pfd, * pfd_end;
822 pfd_end = pfd + walk->len;
823 for (; pfd != pfd_end; pfd++) {
825 * Fish for events. If we found one, record it
826 * and kill poll_table->_qproc, so we don't
827 * needlessly register any other waiters after
828 * this. They'll get immediately deregistered
829 * when we break out and return.
831 if (do_pollfd(pfd, pt, &can_busy_loop,
835 /* found something, stop busy polling */
837 can_busy_loop = false;
842 * All waiters have already been registered, so don't provide
843 * a poll_table->_qproc to them on the next loop iteration.
848 if (signal_pending(current))
851 if (count || timed_out)
854 /* only if found POLL_BUSY_LOOP sockets && not out of time */
855 if (can_busy_loop && !need_resched()) {
857 busy_end = busy_loop_end_time();
860 if (!busy_loop_timeout(busy_end))
866 * If this is the first loop and we have a timeout
867 * given, then we convert to ktime_t and set the to
868 * pointer to the expiry value.
870 if (end_time && !to) {
871 expire = timespec64_to_ktime(*end_time);
875 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
881 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
882 sizeof(struct pollfd))
884 int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
885 struct timespec64 *end_time)
887 struct poll_wqueues table;
888 int err = -EFAULT, fdcount, len, size;
889 /* Allocate small arguments on the stack to save memory and be
890 faster - use long to make sure the buffer is aligned properly
891 on 64 bit archs to avoid unaligned access */
892 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
893 struct poll_list *const head = (struct poll_list *)stack_pps;
894 struct poll_list *walk = head;
895 unsigned long todo = nfds;
897 if (nfds > rlimit(RLIMIT_NOFILE))
900 len = min_t(unsigned int, nfds, N_STACK_PPS);
907 if (copy_from_user(walk->entries, ufds + nfds-todo,
908 sizeof(struct pollfd) * walk->len))
915 len = min(todo, POLLFD_PER_PAGE);
916 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
917 walk = walk->next = kmalloc(size, GFP_KERNEL);
924 poll_initwait(&table);
925 fdcount = do_poll(head, &table, end_time);
926 poll_freewait(&table);
928 for (walk = head; walk; walk = walk->next) {
929 struct pollfd *fds = walk->entries;
932 for (j = 0; j < walk->len; j++, ufds++)
933 if (__put_user(fds[j].revents, &ufds->revents))
941 struct poll_list *pos = walk;
949 static long do_restart_poll(struct restart_block *restart_block)
951 struct pollfd __user *ufds = restart_block->poll.ufds;
952 int nfds = restart_block->poll.nfds;
953 struct timespec64 *to = NULL, end_time;
956 if (restart_block->poll.has_timeout) {
957 end_time.tv_sec = restart_block->poll.tv_sec;
958 end_time.tv_nsec = restart_block->poll.tv_nsec;
962 ret = do_sys_poll(ufds, nfds, to);
965 restart_block->fn = do_restart_poll;
966 ret = -ERESTART_RESTARTBLOCK;
971 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
974 struct timespec64 end_time, *to = NULL;
977 if (timeout_msecs >= 0) {
979 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
980 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
983 ret = do_sys_poll(ufds, nfds, to);
986 struct restart_block *restart_block;
988 restart_block = ¤t->restart_block;
989 restart_block->fn = do_restart_poll;
990 restart_block->poll.ufds = ufds;
991 restart_block->poll.nfds = nfds;
993 if (timeout_msecs >= 0) {
994 restart_block->poll.tv_sec = end_time.tv_sec;
995 restart_block->poll.tv_nsec = end_time.tv_nsec;
996 restart_block->poll.has_timeout = 1;
998 restart_block->poll.has_timeout = 0;
1000 ret = -ERESTART_RESTARTBLOCK;
1005 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1006 struct timespec __user *, tsp, const sigset_t __user *, sigmask,
1009 sigset_t ksigmask, sigsaved;
1011 struct timespec64 end_time, *to = NULL;
1015 if (copy_from_user(&ts, tsp, sizeof(ts)))
1019 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1024 /* XXX: Don't preclude handling different sized sigset_t's. */
1025 if (sigsetsize != sizeof(sigset_t))
1027 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
1030 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
1031 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
1034 ret = do_sys_poll(ufds, nfds, to);
1036 /* We can restart this syscall, usually */
1037 if (ret == -EINTR) {
1039 * Don't restore the signal mask yet. Let do_signal() deliver
1040 * the signal on the way back to userspace, before the signal
1044 memcpy(¤t->saved_sigmask, &sigsaved,
1046 set_restore_sigmask();
1048 ret = -ERESTARTNOHAND;
1050 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
1052 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);