Merge tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 updates from Arnd Bergmann:
 "More syscalls and cleanups

  This concludes the main part of the system call rework for 64-bit
  time_t, which has spread over most of year 2018, the last six system
  calls being

    - ppoll
    - pselect6
    - io_pgetevents
    - recvmmsg
    - futex
    - rt_sigtimedwait

  As before, nothing changes for 64-bit architectures, while 32-bit
  architectures gain another entry point that differs only in the layout
  of the timespec structure. Hopefully in the next release we can wire
  up all 22 of those system calls on all 32-bit architectures, which
  gives us a baseline version for glibc to start using them.

  This does not include the clock_adjtime, getrusage/waitid, and
  getitimer/setitimer system calls. I still plan to have new versions of
  those as well, but they are not required for correct operation of the
  C library since they can be emulated using the old 32-bit time_t based
  system calls.

  Aside from the system calls, there are also a few cleanups here,
  removing old kernel internal interfaces that have become unused after
  all references got removed. The arch/sh cleanups are part of this,
  there were posted several times over the past year without a reaction
  from the maintainers, while the corresponding changes made it into all
  other architectures"

* tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground:
  timekeeping: remove obsolete time accessors
  vfs: replace current_kernel_time64 with ktime equivalent
  timekeeping: remove timespec_add/timespec_del
  timekeeping: remove unused {read,update}_persistent_clock
  sh: remove board_time_init() callback
  sh: remove unused rtc_sh_get/set_time infrastructure
  sh: sh03: rtc: push down rtc class ops into driver
  sh: dreamcast: rtc: push down rtc class ops into driver
  y2038: signal: Add compat_sys_rt_sigtimedwait_time64
  y2038: signal: Add sys_rt_sigtimedwait_time32
  y2038: socket: Add compat_sys_recvmmsg_time64
  y2038: futex: Add support for __kernel_timespec
  y2038: futex: Move compat implementation into futex.c
  io_pgetevents: use __kernel_timespec
  pselect6: use __kernel_timespec
  ppoll: use __kernel_timespec
  signal: Add restore_user_sigmask()
  signal: Add set_user_sigmask()

1 files changed, 143 insertions, 0 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 9a32bc2088c9..53e07d97ffe0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2735,6 +2735,84 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
 }
 EXPORT_SYMBOL(sigprocmask);
 
+/*
+ * The api helps set app-provided sigmasks.
+ *
+ * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
+ * epoll_pwait where a new sigmask is passed from userland for the syscalls.
+ */
+int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
+		     sigset_t *oldset, size_t sigsetsize)
+{
+	if (!usigmask)
+		return 0;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+	if (copy_from_user(set, usigmask, sizeof(sigset_t)))
+		return -EFAULT;
+
+	*oldset = current->blocked;
+	set_current_blocked(set);
+
+	return 0;
+}
+EXPORT_SYMBOL(set_user_sigmask);
+
+#ifdef CONFIG_COMPAT
+int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
+			    sigset_t *set, sigset_t *oldset,
+			    size_t sigsetsize)
+{
+	if (!usigmask)
+		return 0;
+
+	if (sigsetsize != sizeof(compat_sigset_t))
+		return -EINVAL;
+	if (get_compat_sigset(set, usigmask))
+		return -EFAULT;
+
+	*oldset = current->blocked;
+	set_current_blocked(set);
+
+	return 0;
+}
+EXPORT_SYMBOL(set_compat_user_sigmask);
+#endif
+
+/*
+ * restore_user_sigmask:
+ * usigmask: sigmask passed in from userland.
+ * sigsaved: saved sigmask when the syscall started and changed the sigmask to
+ *           usigmask.
+ *
+ * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
+ * epoll_pwait where a new sigmask is passed in from userland for the syscalls.
+ */
+void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved)
+{
+
+	if (!usigmask)
+		return;
+	/*
+	 * When signals are pending, do not restore them here.
+	 * Restoring sigmask here can lead to delivering signals that the above
+	 * syscalls are intended to block because of the sigmask passed in.
+	 */
+	if (signal_pending(current)) {
+		current->saved_sigmask = *sigsaved;
+		set_restore_sigmask();
+		return;
+	}
+
+	/*
+	 * This is needed because the fast syscall return path does not restore
+	 * saved_sigmask when signals are not pending.
+	 */
+	set_current_blocked(sigsaved);
+}
+EXPORT_SYMBOL(restore_user_sigmask);
+
 /**
  *  sys_rt_sigprocmask - change the list of currently blocked signals
  *  @how: whether to add, remove, or set signals
@@ -3254,7 +3332,71 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
 	return ret;
 }
 
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
+		siginfo_t __user *, uinfo,
+		const struct old_timespec32 __user *, uts,
+		size_t, sigsetsize)
+{
+	sigset_t these;
+	struct timespec64 ts;
+	kernel_siginfo_t info;
+	int ret;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (copy_from_user(&these, uthese, sizeof(these)))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_old_timespec32(&ts, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+#endif
+
 #ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
+		struct compat_siginfo __user *, uinfo,
+		struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
+{
+	sigset_t s;
+	struct timespec64 t;
+	kernel_siginfo_t info;
+	long ret;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (get_compat_sigset(&s, uthese))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_timespec64(&t, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user32(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
 		struct compat_siginfo __user *, uinfo,
 		struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
@@ -3285,6 +3427,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
 	return ret;
 }
 #endif
+#endif
 
 /**
  *  sys_kill - send a signal to a process