[DavidSamir]

What

Implements the POSIX timer syscalls ktimer_create, ktimer_settime, ktimer_gettime, ktimer_getoverrun and ktimer_delete in libkernel, in a new libkernel/Time/Ktimer.cpp, following FreeBSD 11 sys/kern/kern_time.c (kern_ktimer_create, realtimer_settime, realtimer_gettime, realtimer_expire, itimespecfix). They replace five discovery stubs that threw.

Moved to libkernel so libkernel imports reach it on Windows. The PS5 3.20 export lists have ktimer_* in libkernel as well as libkernel_sys, and on Windows a libkernel import never searches libkernel_sys (WindowsEntryStubBuilder.cpp:175 only falls back from libkernel_sys and libkernel_web to libkernel). The libkernel_sys stubs are removed, so both imports reach the libkernel exports and the duplicate-export rule holds. The code is unchanged by the move.

• ktimer_create:
  • Only CLOCK_REALTIME (0) and CLOCK_MONOTONIC (4) have timers; any other clock gives EINVAL.
  • A sigev_notify other than SIGEV_NONE, SIGEV_SIGNAL or SIGEV_THREAD_ID gives EINVAL, and for the two signal forms so does a sigev_signo outside 1..128.
  • Ids are the lowest free slot from 3 to 31, as FreeBSD reserves 0..2 for setitimer; EAGAIN when all are in use. A NULL timerid gives EFAULT and keeps no timer.
• ktimer_settime:
  • A NULL value gives EFAULT, and an id that isn't live gives EINVAL.
  • itimespecfix applies to it_value, and to it_interval only when the timer is being armed; a disarming value clears the interval.
  • A non-zero value under one tick rounds up to the tick.
  • TIMER_ABSTIME (1) takes it_value as absolute on the timer's clock.
  • The old value is reported as ktimer_gettime would report it.
• ktimer_gettime: returns the remaining time, or 1 ns for an expiry that is due but not yet processed.
• Expiry: a one-shot timer disarms, and a periodic one moves forward by whole intervals past the current time.
• ktimer_getoverrun: returns 0, because FreeBSD reports it_overrun_last, which only changes when the timer's signal is accepted (itimer_accept).
• ktimer_delete: EINVAL for an id that isn't live.

Why expiry is computed on read: a SIGEV_NONE timer delivers nothing (itimer_fire does nothing for it), so expiry is worked out from the guest clock_gettime whenever the timer is read, and no thread or callout is needed.

What throws: a SIGEV_SIGNAL or SIGEV_THREAD_ID timer, and one created with a NULL sigevent (which FreeBSD turns into SIGEV_SIGNAL with SIGALRM), throws after validation, because delivering a guest signal from a timer is not modelled.

The tick: sub-tick values round to 1 ms, FreeBSD's tick at hz 1000. The console's hz is not measured, since kern.clockrate is unanswered. A debt line records both gaps.

Ktimer.cpp is added to libkernel's source list. The debt line is in libkernel.md, under Functional.

Tested

Windows 11 Pro 26200, WinLibs GCC 15.2.0 r7, Release. This is a CPU-side export, so no GPU is involved.

New test guest_kernel_sys_ktimer, which covers:

• the creation errors, EAGAIN after 29 timers, and a deleted id being reused;
• ids -1, 0, 2, a deleted id and 32 on all four other calls;
• the itimerspec EINVAL fields, and a disarming value clearing the interval;
• 1 ns rounding to 1 ms, as seen in the old value;
• one-shot expiry;
• a periodic timer catching up over missed periods, with getoverrun 0;
• TIMER_ABSTIME in the future, in the past, and in the past on a periodic timer, on both clocks.

Results:

• It passes, and guest_kernel_sys still passes. tools/check_conventions.py passes, including the duplicate-export rule: ktimer_* is exported by libkernel only.
• Link control: with Ktimer.cpp removed from libkernel's sources, the test fails to link (undefined reference to ktimer_create_nid_postfix), so the exports it reaches are libkernel's.
• Negative controls:
  • with the tick rounding removed (TickNanoseconds = 1), the test fails at line 140;
  • with the expiry processing removed, it fails at line 161.
• Overlap: tools/pr_overlap.py crashes on this machine's partial clone, so I ran git merge-tree against every open PR that touches these files. It merges cleanly with all of them except:
  • feat(libkernel): implement the unnamed ksem semaphores #9284, feat(libkernel): implement the named ksem semaphores #9293, feat(libkernel_sys): implement POSIX message queues #9297 and feat(libkernel_sys): implement kmq_notify registration #9302 (mine), which remove neighbouring stubs in Export.Discovery.cpp. That's a one-line resolution by merging main into whichever lands later.
  • fix(libs): libs funcs abi debt 2026 10 20 #9137, which already conflicts with main in files this PR doesn't touch.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[github-actions]

Progress report (0c6a5bd → 642c0d5)

📈 System libraries: 42.14% (+0.04%, +4 implemented, +1 declared, -5 removed functions)

✅ 4 implemented

Library	Name
libkernel	ktimer_delete_nid_postfix
libkernel	ktimer_getoverrun_nid_postfix
libkernel	ktimer_gettime_nid_postfix
libkernel	ktimer_settime_nid_postfix

🆕 1 declared as stubs

Library	Name
libkernel	ktimer_create_nid_postfix

🗑️ 5 removed

Library	Name
libkernel_sys	ktimer_create_nid_postfix
libkernel_sys	ktimer_delete_nid_postfix
libkernel_sys	ktimer_getoverrun_nid_postfix
libkernel_sys	ktimer_gettime_nid_postfix
libkernel_sys	ktimer_settime_nid_postfix

[github-actions]

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 4563	core/libs/prx/libkernel/CMakeLists.txt
PR 5021	core/libs/CMakeLists.txt core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 6044	core/libs/CMakeLists.txt core/libs/prx/libkernel/CMakeLists.txt
PR 6149	docs/dev/debt/libkernel.md
PR 6469	core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 6740	docs/dev/debt/libkernel.md
PR 6830	core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 6936	core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 7049	docs/dev/debt/libkernel.md
PR 7088	docs/dev/debt/libkernel.md
PR 7105	docs/dev/debt/libkernel.md
PR 7121	docs/dev/debt/libkernel.md
PR 7149	docs/dev/debt/libkernel.md
PR 7201	core/libs/CMakeLists.txt core/libs/prx/libkernel/CMakeLists.txt
PR 7275	core/libs/CMakeLists.txt
PR 7509	docs/dev/debt/libkernel.md
PR 7565	docs/dev/debt/libkernel.md
PR 7622	core/libs/CMakeLists.txt
PR 7653	docs/dev/debt/libkernel.md
PR 7780	core/libs/CMakeLists.txt
PR 8010	docs/dev/debt/libkernel.md
PR 8264	core/libs/CMakeLists.txt
PR 8285	core/libs/CMakeLists.txt
PR 8520	core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 8553	docs/dev/debt/libkernel.md
PR 8650	core/libs/CMakeLists.txt
PR 9019	core/libs/CMakeLists.txt core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9040	core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9103	core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9133	docs/dev/debt/libkernel.md
PR 9161	core/libs/CMakeLists.txt core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9162	core/libs/CMakeLists.txt core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9172	core/libs/CMakeLists.txt core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9173	core/libs/CMakeLists.txt
PR 9208	core/libs/CMakeLists.txt
PR 9212	core/libs/CMakeLists.txt
PR 9221	core/libs/CMakeLists.txt
PR 9442	core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9571	core/libs/CMakeLists.txt
PR 9669	core/libs/prx/libkernel/CMakeLists.txt docs/dev/debt/libkernel.md
PR 9693	core/libs/prx/libkernel/CMakeLists.txt core/libs/prx/libkernel_sys/Export.Discovery.cpp docs/dev/debt/libkernel.md
PR 9713	core/libs/prx/libkernel_sys/Export.Discovery.cpp
PR 9802	core/libs/CMakeLists.txt
PR 9924	core/libs/CMakeLists.txt
PR 9933	core/libs/CMakeLists.txt

[DavidSamir]

Linux: Ubuntu 24.04.1 LTS (WSL2), GCC 13.3.0, Release; head 642c0d56a merged onto main 8c26eac3c.

• guest_kernel_sys_ktimer passes 3/3.
• Link control: with ktimer_create_nid_postfix renamed in Ktimer.cpp (instead of removing the file from the sources), the test fails to link: undefined reference to ktimer_create_nid_postfix, as listed.
• Negative control: with the tick rounding removed (TickNanoseconds = 1), it fails at line 140. The PR text says line 142; the control fails, but at a different line on this head. I did not run the expiry-processing control.

Run from the PC (Windows host, Linux in WSL2), not from the PR author's machine.

[harisibrar1]

Checked against main 8b3e398 and FreeBSD releng/11.4 sys/kern/kern_time.c (kern_ktimer_create, kern_ktimer_settime/gettime/getoverrun/delete, realtimer_settime/gettime/expire, itimespecfix, itimer_accept):

• Main still has only the five throwing ktimer_* stubs in libkernel_sys/Export.Discovery.cpp, and this head merges onto main cleanly.
• The clock set (0 and 4), the sigevent checks (NONE, SIGNAL and THREAD_ID, signo 1..128), and ids 3..31 with EAGAIN all match kern_ktimer_create. So does the EAGAIN-before-EFAULT order for a NULL timerid, since FreeBSD only fails at the copyout.
• The settime order (EFAULT for a NULL value before the id check), the interval being fixed only when armed, the old value taken before the store, and the absolute conversion all match realtimer_settime. Gettime checks the id before EFAULT, as kern_ktimer_gettime + copyout do.
• The closed-form periodic catch-up gives the same next expiry as the while (cts >= value) loop in realtimer_expire, and getoverrun returning 0 is right because it_overrun_last only changes in itimer_accept.
• Signal-delivering timers (including NULL sigevent → SIGEV_SIGNAL/SIGALRM) throw after validation, before a slot is taken, and are in the debt file. Good.
• Small nit, not blocking: in Remaining, Expire always leaves value == 0 or value > now, so the GuestTimespec{0, 1} branch at Ktimer.cpp:98 can't be reached. It could be dropped, and the PR text adjusted to match.

Reviewed with AI assistance (Claude Code); the checks above were run locally on my machine.