linux/include/asm-generic
Linus Torvalds bf9aa14fc5 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
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Merge tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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()
  ...
2024-11-19 16:35:06 -08:00
..
bitops bitops: Change function return types from long to int 2024-05-03 17:04:50 +02:00
vdso vdso: Remove timekeeper argument of __arch_update_vsyscall() 2024-10-15 17:50:28 +02:00
access_ok.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
agp.h char/agp: introduce asm-generic/agp.h 2023-02-13 22:13:29 +01:00
archrandom.h random: handle archrandom with multiple longs 2022-07-25 13:26:14 +02:00
asm-offsets.h
asm-prototypes.h
atomic64.h
atomic.h locking/atomic: make atomic*_{cmp,}xchg optional 2023-06-05 09:57:14 +02:00
audit_change_attr.h fs/xattr: add *at family syscalls 2024-11-06 12:59:44 -05:00
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h
barrier.h sched: Add missing memory barrier in switch_mm_cid 2024-04-16 13:59:45 +02:00
bitops.h include: move find.h from asm_generic to linux 2022-01-15 08:47:31 -08:00
bitsperlong.h
bug.h bug: Improve comment 2024-05-07 14:20:48 +02:00
cache.h
cacheflush.h mm: Introduce flush_cache_vmap_early() 2023-12-14 00:23:17 -08:00
cfi.h cfi: Flip headers 2023-12-15 16:25:55 -08:00
checksum.h asm-generic: Improve csum_fold 2024-01-17 17:52:29 -08:00
cmpxchg-local.h asm-generic: Fix 32 bit __generic_cmpxchg_local 2024-01-05 23:19:14 +01:00
cmpxchg.h asm-generic: avoid __generic_cmpxchg_local warnings 2023-04-04 17:58:11 +02:00
codetag.lds.h lib: add allocation tagging support for memory allocation profiling 2024-04-25 20:55:52 -07:00
compat.h asm-generic: compat: fix compat_arg_u64() and compat_arg_u64_dual() 2022-11-01 10:20:11 +11:00
current.h asm-generic: current: Don't include thread-info.h if building asm 2023-08-26 22:38:49 +02:00
delay.h delay: Rework udelay and ndelay 2024-10-16 00:36:47 +02:00
device.h
div64.h
dma-mapping.h dma-mapping: no need to pass a bus_type into get_arch_dma_ops() 2023-02-15 12:35:20 +01:00
dma.h
early_ioremap.h
emergency-restart.h
error-injection.h docs: fault-injection: add requirements of error injectable functions 2023-02-02 22:50:00 -08:00
exec.h
extable.h
fixmap.h fixmap: Remove unused set_fixmap_offset_io() 2024-07-11 17:41:23 +02:00
flat.h
ftrace.h
futex.h
getorder.h
hardirq.h
hugetlb.h mm: provide mm_struct and address to huge_ptep_get() 2024-07-12 15:52:15 -07:00
hw_irq.h
hyperv-tlfs.h hyperv-fixes for v6.9-rc4 2024-04-11 16:23:56 -07:00
int-ll64.h
io.h asm-generic/io.h: kill vmalloc.h dependency 2024-04-25 20:55:50 -07:00
ioctl.h
iomap.h asm-generic/iomap.h: remove ARCH_HAS_IOREMAP_xx macros 2023-08-18 10:12:32 -07:00
irq_regs.h
irq_work.h
irq.h
irqflags.h
Kbuild move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
kdebug.h
kmap_size.h
kprobes.h
kvm_para.h
kvm_types.h
linkage.h
local64.h locking/generic: Wire up local{,64}_try_cmpxchg() 2023-04-29 09:09:09 +02:00
local.h locking/generic: Wire up local{,64}_try_cmpxchg() 2023-04-29 09:09:09 +02:00
logic_io.h
mcs_spinlock.h
memory_model.h mm, arch: add generic implementation of pfn_valid() for FLATMEM 2023-02-09 16:51:41 -08:00
mm_hooks.h mm: remove arch_unmap() 2024-09-01 20:26:13 -07:00
mmiowb_types.h
mmiowb.h
mmu_context.h
mmu.h
mmzone.h arch, mm: move definition of node_data to generic code 2024-09-03 21:15:28 -07:00
module.h
module.lds.h
mshyperv.h hyperv-fixes for v6.9-rc4 2024-04-11 16:23:56 -07:00
msi.h genirq: Get rid of GENERIC_MSI_IRQ_DOMAIN 2022-11-17 15:15:20 +01:00
nommu_context.h
numa.h arch_numa: switch over to numa_memblks 2024-09-03 21:15:32 -07:00
param.h
parport.h
pci_iomap.h PCI: Stub __pci_ioport_map() for arches that don't support it at all 2022-07-29 12:01:00 -05:00
pci.h asm-generic: Add new pci.h and use it 2022-07-22 17:34:57 -05:00
percpu.h percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg() 2023-06-08 10:28:39 +02:00
pgalloc.h mm: change inlined allocation helpers to account at the call site 2024-04-25 20:55:59 -07:00
pgtable_uffd.h
pgtable-nop4d.h
pgtable-nopmd.h mm: recover pud_leaf() definitions in nopmd case 2024-03-13 12:12:21 -07:00
pgtable-nopud.h
preempt.h riscv: support PREEMPT_DYNAMIC with static keys 2023-08-31 00:18:34 -07:00
qrwlock_types.h locking/qrwlock: Change "queue rwlock" to "queued rwlock" 2022-05-11 16:27:04 +02:00
qrwlock.h asm-generic changes for 5.19 2022-05-26 10:50:30 -07:00
qspinlock_types.h
qspinlock.h asm-generic: qspinlock: fix queued_spin_value_unlocked() implementation 2023-11-22 09:32:49 -08:00
resource.h
runtime-const.h runtime constants: add default dummy infrastructure 2024-06-19 12:34:34 -07:00
rwonce.h
seccomp.h
sections.h jump_label,module: Don't alloc static_key_mod for __ro_after_init keys 2024-03-22 11:18:16 +01:00
serial.h
set_memory.h
shmparam.h
signal.h asm-generic: Remove empty #ifdef SA_RESTORER 2022-09-10 09:56:53 +02:00
simd.h
softirq_stack.h asm-generic: Conditionally enable do_softirq_own_stack() via Kconfig. 2022-09-05 17:20:55 +02:00
spinlock_types.h asm-generic: ticket-lock: New generic ticket-based spinlock 2022-05-11 11:49:38 -07:00
spinlock.h asm-generic: ticket-lock: Optimize arch_spin_value_unlocked() 2023-09-21 10:17:00 +02:00
statfs.h
string.h
switch_to.h
syscall.h ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h 2022-03-10 13:35:08 -06:00
syscalls.h syscalls: mmap(): use unsigned offset type consistently 2024-06-25 15:57:38 +02:00
timex.h
tlb.h mm/mmu_gather: add __tlb_remove_folio_pages() 2024-02-22 15:27:17 -08:00
tlbflush.h
topology.h
trace_clock.h
uaccess.h move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
user.h
vermagic.h
vga.h
video.h arch: Rename fbdev header and source files 2024-05-03 17:07:50 +02:00
vmlinux.lds.h asm-generic updates for 6.12 2024-09-26 11:54:40 -07:00
word-at-a-time.h kernel.h: removed REPEAT_BYTE from kernel.h 2024-02-01 09:47:59 -08:00
xor.h lib/xor: make xor prototypes more friendly to compiler vectorization 2022-02-11 20:39:39 +11:00