Merge tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull timer updates from Thomas Gleixner:
 "A rather large update for timekeeping and timers:

   - The final step to get rid of auto-rearming posix-timers

     posix-timers are currently auto-rearmed by the kernel when the
     signal of the timer is ignored so that the timer signal can be
     delivered once the corresponding signal is unignored.

     This requires to throttle the timer to prevent a DoS by small
     intervals and keeps the system pointlessly out of low power states
     for no value. This is a long standing non-trivial problem due to
     the lock order of posix-timer lock and the sighand lock along with
     life time issues as the timer and the sigqueue have different life
     time rules.

     Cure this by:

       - Embedding the sigqueue into the timer struct to have the same
         life time rules. Aside of that this also avoids the lookup of
         the timer in the signal delivery and rearm path as it's just a
         always valid container_of() now.

       - Queuing ignored timer signals onto a seperate ignored list.

       - Moving queued timer signals onto the ignored list when the
         signal is switched to SIG_IGN before it could be delivered.

       - Walking the ignored list when SIG_IGN is lifted and requeue the
         signals to the actual signal lists. This allows the signal
         delivery code to rearm the timer.

     This also required to consolidate the signal delivery rules so they
     are consistent across all situations. With that all self test
     scenarios finally succeed.

   - Core infrastructure for VFS multigrain timestamping

     This is required to allow the kernel to use coarse grained time
     stamps by default and switch to fine grained time stamps when inode
     attributes are actively observed via getattr().

     These changes have been provided to the VFS tree as well, so that
     the VFS specific infrastructure could be built on top.

   - Cleanup and consolidation of the sleep() infrastructure

       - Move all sleep and timeout functions into one file

       - Rework udelay() and ndelay() into proper documented inline
         functions and replace the hardcoded magic numbers by proper
         defines.

       - Rework the fsleep() implementation to take the reality of the
         timer wheel granularity on different HZ values into account.
         Right now the boundaries are hard coded time ranges which fail
         to provide the requested accuracy on different HZ settings.

       - Update documentation for all sleep/timeout related functions
         and fix up stale documentation links all over the place

       - Fixup a few usage sites

   - Rework of timekeeping and adjtimex(2) to prepare for multiple PTP
     clocks

     A system can have multiple PTP clocks which are participating in
     seperate and independent PTP clock domains. So far the kernel only
     considers the PTP clock which is based on CLOCK TAI relevant as
     that's the clock which drives the timekeeping adjustments via the
     various user space daemons through adjtimex(2).

     The non TAI based clock domains are accessible via the file
     descriptor based posix clocks, but their usability is very limited.
     They can't be accessed fast as they always go all the way out to
     the hardware and they cannot be utilized in the kernel itself.

     As Time Sensitive Networking (TSN) gains traction it is required to
     provide fast user and kernel space access to these clocks.

     The approach taken is to utilize the timekeeping and adjtimex(2)
     infrastructure to provide this access in a similar way how the
     kernel provides access to clock MONOTONIC, REALTIME etc.

     Instead of creating a duplicated infrastructure this rework
     converts timekeeping and adjtimex(2) into generic functionality
     which operates on pointers to data structures instead of using
     static variables.

     This allows to provide time accessors and adjtimex(2) functionality
     for the independent PTP clocks in a subsequent step.

   - Consolidate hrtimer initialization

     hrtimers are set up by initializing the data structure and then
     seperately setting the callback function for historical reasons.

     That's an extra unnecessary step and makes Rust support less
     straight forward than it should be.

     Provide a new set of hrtimer_setup*() functions and convert the
     core code and a few usage sites of the less frequently used
     interfaces over.

     The bulk of the htimer_init() to hrtimer_setup() conversion is
     already prepared and scheduled for the next merge window.

   - Drivers:

       - Ensure that the global timekeeping clocksource is utilizing the
         cluster 0 timer on MIPS multi-cluster systems.

         Otherwise CPUs on different clusters use their cluster specific
         clocksource which is not guaranteed to be synchronized with
         other clusters.

       - Mostly boring cleanups, fixes, improvements and code movement"

* tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits)
  posix-timers: Fix spurious warning on double enqueue versus do_exit()
  clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties
  clocksource/drivers/gpx: Remove redundant casts
  clocksource/drivers/timer-ti-dm: Fix child node refcount handling
  dt-bindings: timer: actions,owl-timer: convert to YAML
  clocksource/drivers/ralink: Add Ralink System Tick Counter driver
  clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource
  clocksource/drivers/timer-ti-dm: Don't fail probe if int not found
  clocksource/drivers:sp804: Make user selectable
  clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions
  hrtimers: Delete hrtimer_init_on_stack()
  alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack()
  io_uring: Switch to use hrtimer_setup_on_stack()
  sched/idle: Switch to use hrtimer_setup_on_stack()
  hrtimers: Delete hrtimer_init_sleeper_on_stack()
  wait: Switch to use hrtimer_setup_sleeper_on_stack()
  timers: Switch to use hrtimer_setup_sleeper_on_stack()
  net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack()
  futex: Switch to use hrtimer_setup_sleeper_on_stack()
  fs/aio: Switch to use hrtimer_setup_sleeper_on_stack()
  ...

diff --cc MAINTAINERS
Simple merge

diff --cc arch/riscv/configs/defconfig
Simple merge

diff --cc arch/x86/Kconfig
Simple merge

diff --cc fs/aio.c
Simple merge

diff --cc fs/proc/base.c
Simple merge

diff --cc fs/timerfd.c
Simple merge

diff --cc include/linux/tick.h
Simple merge

diff --cc include/linux/wait.h
Simple merge

diff --cc io_uring/io_uring.c
Simple merge

diff --cc io_uring/rw.c
index cce8bc2ecd3fa493e7ccbd48170bb1ea90311f26,f023ff49c6883cbe00aab4979e7c2fd115e5cad2..0bcb83e4ce3cf9b0d02da3f6cd504a377931ccde
--- 1/io_uring/rw.c
--- 2/io_uring/rw.c
+++ b/io_uring/rw.c
@@@ -1139,78 -1112,6 +1139,78 @@@ void io_rw_fail(struct io_kiocb *req
        io_req_set_res(req, res, req->cqe.flags);
  }
  
-       hrtimer_init_sleeper_on_stack(&timer, CLOCK_MONOTONIC, mode);
 +static int io_uring_classic_poll(struct io_kiocb *req, struct io_comp_batch *iob,
 +                              unsigned int poll_flags)
 +{
 +      struct file *file = req->file;
 +
 +      if (req->opcode == IORING_OP_URING_CMD) {
 +              struct io_uring_cmd *ioucmd;
 +
 +              ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
 +              return file->f_op->uring_cmd_iopoll(ioucmd, iob, poll_flags);
 +      } else {
 +              struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
 +
 +              return file->f_op->iopoll(&rw->kiocb, iob, poll_flags);
 +      }
 +}
 +
 +static u64 io_hybrid_iopoll_delay(struct io_ring_ctx *ctx, struct io_kiocb *req)
 +{
 +      struct hrtimer_sleeper timer;
 +      enum hrtimer_mode mode;
 +      ktime_t kt;
 +      u64 sleep_time;
 +
 +      if (req->flags & REQ_F_IOPOLL_STATE)
 +              return 0;
 +
 +      if (ctx->hybrid_poll_time == LLONG_MAX)
 +              return 0;
 +
 +      /* Using half the running time to do schedule */
 +      sleep_time = ctx->hybrid_poll_time / 2;
 +
 +      kt = ktime_set(0, sleep_time);
 +      req->flags |= REQ_F_IOPOLL_STATE;
 +
 +      mode = HRTIMER_MODE_REL;
++      hrtimer_setup_sleeper_on_stack(&timer, CLOCK_MONOTONIC, mode);
 +      hrtimer_set_expires(&timer.timer, kt);
 +      set_current_state(TASK_INTERRUPTIBLE);
 +      hrtimer_sleeper_start_expires(&timer, mode);
 +
 +      if (timer.task)
 +              io_schedule();
 +
 +      hrtimer_cancel(&timer.timer);
 +      __set_current_state(TASK_RUNNING);
 +      destroy_hrtimer_on_stack(&timer.timer);
 +      return sleep_time;
 +}
 +
 +static int io_uring_hybrid_poll(struct io_kiocb *req,
 +                              struct io_comp_batch *iob, unsigned int poll_flags)
 +{
 +      struct io_ring_ctx *ctx = req->ctx;
 +      u64 runtime, sleep_time;
 +      int ret;
 +
 +      sleep_time = io_hybrid_iopoll_delay(ctx, req);
 +      ret = io_uring_classic_poll(req, iob, poll_flags);
 +      runtime = ktime_get_ns() - req->iopoll_start - sleep_time;
 +
 +      /*
 +       * Use minimum sleep time if we're polling devices with different
 +       * latencies. We could get more completions from the faster ones.
 +       */
 +      if (ctx->hybrid_poll_time > runtime)
 +              ctx->hybrid_poll_time = runtime;
 +
 +      return ret;
 +}
 +
  int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
  {
        struct io_wq_work_node *pos, *start, *prev;

diff --cc io_uring/timeout.c
Simple merge

diff --cc kernel/cpu.c
index c4aaf73dec9e606e031273a9f80583512c9c6a4c,895f3287e3f3fb2c72d15ef919edb5baee642208..6e34b52cb5ce714571bb5778648b9720df39ddb1
--- 1/kernel/cpu.c
--- 2/kernel/cpu.c
+++ b/kernel/cpu.c
@@@ -1338,9 -1338,6 +1338,8 @@@ static int takedown_cpu(unsigned int cp
  
        cpuhp_bp_sync_dead(cpu);
  
-       tick_cleanup_dead_cpu(cpu);
 +      lockdep_cleanup_dead_cpu(cpu, idle_thread_get(cpu));
 +
        /*
         * Callbacks must be re-integrated right away to the RCU state machine.
         * Otherwise an RCU callback could block a further teardown function

diff --cc kernel/fork.c
Simple merge

diff --cc kernel/futex/core.c
Simple merge

diff --cc kernel/sched/idle.c
Simple merge

diff --cc kernel/signal.c
Simple merge

diff --cc kernel/time/hrtimer.c
Simple merge

diff --cc kernel/time/tick-sched.c
Simple merge

diff --cc kernel/time/timekeeping.c
index cdd61990cd14ad0430783f00160cfdec759e5cdb,d115adebc418c77837a6096a784e75906a080fab..0ca85ff4fbb4aeff74b310d188dc78426fc5004d
--- 1/kernel/time/timekeeping.c
--- 2/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@@ -462,11 -375,11 +377,11 @@@ static __always_inline u64 __ktime_get_
        u64 now;
  
        do {
 -              seq = raw_read_seqcount_latch(&tkf->seq);
 +              seq = read_seqcount_latch(&tkf->seq);
                tkr = tkf->base + (seq & 0x01);
                now = ktime_to_ns(tkr->base);
-               now += __timekeeping_get_ns(tkr);
+               now += timekeeping_get_ns(tkr);
 -      } while (raw_read_seqcount_latch_retry(&tkf->seq, seq));
 +      } while (read_seqcount_latch_retry(&tkf->seq, seq));
  
        return now;
  }

diff --cc kernel/time/timer.c
Simple merge

diff --cc kernel/time/vsyscall.c
Simple merge

diff --cc lib/Kconfig.debug
Simple merge

diff --cc mm/damon/core.c
Simple merge

diff --cc net/bluetooth/hci_event.c
Simple merge

diff --cc net/netfilter/xt_IDLETIMER.c
Simple merge