rpi5 kernel

[acumartini]

Any plans to support one of the newer rpi5 linux versions?

[shuhaowu]

After 24.04 is released

[shuhaowu]

@razr are you working on this? Anything I can do to help to speed it up?

[razr]

yes, I have built an RPI5 version

[shuhaowu]

How did you build this? Trying it today and got this error:

make ARCH=arm64 KERNELRELEASE=6.8.12-rt11-raspi KBUILD_BUILD_VERSION=2 CROSS_COMPILE=aarch64-linux-gnu- headers all
mkdir -p /linux_build/linux-raspi/tools/bpf/resolve_btfids && make O=/linux_build/linux-raspi subdir=tools/bpf/resolve_btfids --no-print-directory -C bpf/resolve_btfids
  INSTALL libsubcmd_headers
  CC      arch/arm64/kernel/asm-offsets.s
In file included from ./include/linux/mm_types.h:13,
                 from ./include/linux/mmzone.h:22,
                 from ./include/linux/gfp.h:7,
                 from ./include/linux/slab.h:16,
                 from ./include/linux/resource_ext.h:11,
                 from ./include/linux/acpi.h:13,
                 from ./include/acpi/apei.h:9,
                 from ./include/acpi/ghes.h:5,
                 from ./include/linux/arm_sdei.h:8,
                 from arch/arm64/kernel/asm-offsets.c:10:
./include/linux/rwsem.h: In function ‘rwsem_assert_held_write_nolockdep’:
./include/linux/rwsem.h:177:35: error: passing argument 1 of ‘rw_base_assert_held_write’ from incompatible pointer type [-Werror=incompatible-pointer-types]
  177 |         rw_base_assert_held_write(sem);
      |                                   ^~~
      |                                   |
      |                                   const struct rw_semaphore *
In file included from ./include/linux/rwlock_types.h:55,
                 from ./include/linux/spinlock_types.h:74,
                 from ./include/linux/spinlock.h:89,
                 from ./include/linux/mmzone.h:8:
./include/linux/rwbase_rt.h:34:70: note: expected ‘const struct rwbase_rt *’ but argument is of type ‘const struct rw_semaphore *’
   34 | static inline void rw_base_assert_held_write(const struct rwbase_rt *rwb)
      |                                              ~~~~~~~~~~~~~~~~~~~~~~~~^~~
cc1: some warnings being treated as errors

[shuhaowu]

Maybe the issue is we are cloning master instead of a specific branch?

[shuhaowu]

I tried a few ways of patching the kernel but it doesn't seem like the versions line up and the preempt rt patches doesn't seem to patch properly with any version...

[shuhaowu]

I'm trying to now patching the kernel manually. It doesn't seem like we have an aligned Ubuntu kernel version vs the PREEMPT_RT patch version on kernel 6.8 as 6.8 is no longer supported. I see that kernel is supporting 6.8.2 and the closest Ubuntu kernel is 6.8.4 (Ubuntu-raspi-6.8.0-1005.5).

When applying the 6.8.2 patchset from PREEMPT_RT, I'm seeing that 8 patches fail to apply.

[razr]

let me look into it. I've started a new kernel build: https://github.com/ros-realtime/linux-real-time-kernel-builder/actions/runs/15974212813

The build uses 6.8.0 kernel and applies patch-6.8.2-rt11

[shuhaowu]

There are some patch failures:

HEAD is now at 75867ff0890f UBUNTU: Ubuntu-raspi-6.8.0-1005.5
Patching with ../patches/0001-arm-Disable-jump-label-on-PREEMPT_RT.patch...
SUCCESS

Patching with ../patches/0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch...
SUCCESS

Patching with ../patches/0001-net-Remove-conditional-threaded-NAPI-wakeup-based-on.patch...
SUCCESS

Patching with ../patches/0001-perf-Move-irq_work_queue-where-the-event-is-prepared.patch...
SUCCESS

Patching with ../patches/0001-printk-ringbuffer-Clarify-special-lpos-values.patch...
SUCCESS

Patching with ../patches/0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch...
SUCCESS

Patching with ../patches/0001-serial-amba-pl011-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch...
SUCCESS

Patching with ../patches/0002-net-Allow-to-use-SMP-threads-for-backlog-NAPI.patch...
SUCCESS

Patching with ../patches/0002-perf-Enqueue-SIGTRAP-always-via-task_work.patch...
SUCCESS

Patching with ../patches/0002-printk-For-suppress_panic_printk-check-for-other-CPU.patch...
SUCCESS

Patching with ../patches/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0002-softirq-Add-function-to-preempt-serving-softirqs.patch...
SUCCESS

Patching with ../patches/0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch...
SUCCESS

Patching with ../patches/0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch...
SUCCESS

Patching with ../patches/0003-net-Use-backlog-NAPI-to-clean-up-the-defer_list.patch...
SUCCESS

Patching with ../patches/0003-perf-Remove-perf_swevent_get_recursion_context-from-.patch...
SUCCESS

Patching with ../patches/0003-printk-Avoid-non-panic-CPUs-writing-to-ringbuffer.patch...
SUCCESS

Patching with ../patches/0003-serial-bcm63xx-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0003-time-Allow-to-preempt-after-a-callback.patch...
SUCCESS

Patching with ../patches/0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch...
SUCCESS

Patching with ../patches/0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch...
SUCCESS

Patching with ../patches/0004-mm-debug-Provide-VM_WARN_ON_IRQS_ENABLED.patch...
error: patch failed: include/linux/mmdebug.h:94
error: include/linux/mmdebug.h: patch does not apply
error: patch failed: lib/Kconfig.debug:803
error: lib/Kconfig.debug: patch does not apply
FAILED  ../patches/0004-mm-debug-Provide-VM_WARN_ON_IRQS_ENABLED.patch

Patching with ../patches/0004-net-Rename-rps_lock-to-backlog_lock.patch...
SUCCESS

Patching with ../patches/0004-panic-Flush-kernel-log-buffer-at-the-end.patch...
SUCCESS

Patching with ../patches/0004-perf-Split-__perf_pending_irq-out-of-perf_pending_ir.patch...
SUCCESS

Patching with ../patches/0004-serial-meson-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch...
SUCCESS

Patching with ../patches/0005-dump_stack-Do-not-get-cpu_sync-for-panic-CPU.patch...
SUCCESS

Patching with ../patches/0005-mm-memcontrol-Replace-the-PREEMPT_RT-conditionals.patch...
error: patch failed: mm/memcontrol.c:597
error: mm/memcontrol.c: patch does not apply
FAILED  ../patches/0005-mm-memcontrol-Replace-the-PREEMPT_RT-conditionals.patch

Patching with ../patches/0005-serial-msm-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch...
SUCCESS

Patching with ../patches/0006-mm-compaction-Get-rid-of-RT-ifdeffery.patch...
error: patch failed: mm/Kconfig:579
error: mm/Kconfig: patch does not apply
error: patch failed: mm/compaction.c:1727
error: mm/compaction.c: patch does not apply
FAILED  ../patches/0006-mm-compaction-Get-rid-of-RT-ifdeffery.patch

Patching with ../patches/0006-printk-Add-notation-to-console_srcu-locking.patch...
SUCCESS

Patching with ../patches/0006-serial-omap-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch...
SUCCESS

Patching with ../patches/0007-flex_proportions-Disable-preemption-entering-the-wri.patch...
error: patch failed: lib/flex_proportions.c:70
error: lib/flex_proportions.c: patch does not apply
FAILED  ../patches/0007-flex_proportions-Disable-preemption-entering-the-wri.patch

Patching with ../patches/0007-printk-Properly-deal-with-nbcon-consoles-on-seq-init.patch...
SUCCESS

Patching with ../patches/0007-serial-pxa-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch...
SUCCESS

Patching with ../patches/0008-printk-nbcon-Remove-return-value-for-write_atomic.patch...
SUCCESS

Patching with ../patches/0008-serial-sunplus-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch...
SUCCESS

Patching with ../patches/0009-printk-Check-printk_deferred_enter-_exit-usage.patch...
SUCCESS

Patching with ../patches/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch...
SUCCESS

Patching with ../patches/0010-drm-i915-Drop-the-irqs_disabled-check.patch...
SUCCESS

Patching with ../patches/0010-printk-nbcon-Add-detailed-doc-for-write_atomic.patch...
SUCCESS

Patching with ../patches/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch...
SUCCESS

Patching with ../patches/0011-printk-nbcon-Add-callbacks-to-synchronize-with-drive.patch...
SUCCESS

Patching with ../patches/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch...
SUCCESS

Patching with ../patches/0012-printk-nbcon-Use-driver-synchronization-while-regist.patch...
SUCCESS

Patching with ../patches/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch...
SUCCESS

Patching with ../patches/0013-serial-core-Provide-low-level-functions-to-lock-port.patch...
SUCCESS

Patching with ../patches/0013-serial-pch-Invoke-handle_rx_to-directly.patch...
SUCCESS

Patching with ../patches/0014-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch...
SUCCESS

Patching with ../patches/0014-serial-pch-Make-push_rx-return-void.patch...
SUCCESS

Patching with ../patches/0015-printk-nbcon-Do-not-rely-on-proxy-headers.patch...
SUCCESS

Patching with ../patches/0015-serial-pch-Don-t-disable-interrupts-while-acquiring-.patch...
SUCCESS

Patching with ../patches/0016-printk-nbcon-Fix-kerneldoc-for-enums.patch...
SUCCESS

Patching with ../patches/0016-serial-pch-Don-t-initialize-uart_port-s-spin_lock.patch...
SUCCESS

Patching with ../patches/0017-printk-Make-console_is_usable-available-to-nbcon.patch...
SUCCESS

Patching with ../patches/0017-serial-pch-Remove-eg20t_port-lock.patch...
SUCCESS

Patching with ../patches/0018-printk-Let-console_is_usable-handle-nbcon.patch...
SUCCESS

Patching with ../patches/0018-serial-pch-Use-uart_prepare_sysrq_char.patch...
SUCCESS

Patching with ../patches/0019-printk-Add-flags-argument-for-console_is_usable.patch...
SUCCESS

Patching with ../patches/0020-printk-nbcon-Provide-function-to-flush-using-write_a.patch...
SUCCESS

Patching with ../patches/0021-printk-Track-registered-boot-consoles.patch...
SUCCESS

Patching with ../patches/0022-printk-nbcon-Use-nbcon-consoles-in-console_flush_all.patch...
SUCCESS

Patching with ../patches/0023-printk-nbcon-Assign-priority-based-on-CPU-state.patch...
SUCCESS

Patching with ../patches/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch...
SUCCESS

Patching with ../patches/0025-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch...
SUCCESS

Patching with ../patches/0026-printk-Track-nbcon-consoles.patch...
SUCCESS

Patching with ../patches/0027-printk-Coordinate-direct-printing-in-panic.patch...
SUCCESS

Patching with ../patches/0028-printk-nbcon-Implement-emergency-sections.patch...
SUCCESS

Patching with ../patches/0029-panic-Mark-emergency-section-in-warn.patch...
SUCCESS

Patching with ../patches/0030-panic-Mark-emergency-section-in-oops.patch...
SUCCESS

Patching with ../patches/0031-rcu-Mark-emergency-sections-in-rcu-stalls.patch...
SUCCESS

Patching with ../patches/0032-lockdep-Mark-emergency-sections-in-lockdep-splats.patch...
SUCCESS

Patching with ../patches/0033-printk-nbcon-Introduce-printing-kthreads.patch...
SUCCESS

Patching with ../patches/0034-printk-Atomic-print-in-printk-context-on-shutdown.patch...
SUCCESS

Patching with ../patches/0035-printk-nbcon-Add-context-to-console_is_usable.patch...
SUCCESS

Patching with ../patches/0036-printk-nbcon-Add-printer-thread-wakeups.patch...
SUCCESS

Patching with ../patches/0037-printk-nbcon-Stop-threads-on-shutdown-reboot.patch...
SUCCESS

Patching with ../patches/0038-printk-nbcon-Start-printing-threads.patch...
SUCCESS

Patching with ../patches/0039-printk-Provide-helper-for-message-prepending.patch...
SUCCESS

Patching with ../patches/0040-printk-nbcon-Show-replay-message-on-takeover.patch...
SUCCESS

Patching with ../patches/0041-proc-Add-nbcon-support-for-proc-consoles.patch...
SUCCESS

Patching with ../patches/0042-tty-sysfs-Add-nbcon-support-for-active.patch...
SUCCESS

Patching with ../patches/0043-printk-nbcon-Provide-function-to-reacquire-ownership.patch...
SUCCESS

Patching with ../patches/0044-serial-8250-Switch-to-nbcon-console.patch...
SUCCESS

Patching with ../patches/0045-serial-8250-Revert-drop-lockdep-annotation-from-seri.patch...
SUCCESS

Patching with ../patches/0046-printk-Add-kthread-for-all-legacy-consoles.patch...
SUCCESS

Patching with ../patches/0047-printk-Provide-threadprintk-boot-argument.patch...
SUCCESS

Patching with ../patches/0048-printk-Avoid-false-positive-lockdep-report-for-legac.patch...
SUCCESS

Patching with ../patches/Add_localversion_for_-RT_release.patch...
SUCCESS

Patching with ../patches/ARM64__Allow_to_enable_RT.patch...
SUCCESS

Patching with ../patches/arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch...
error: patch failed: arch/arm64/Kconfig:98
error: arch/arm64/Kconfig: patch does not apply
FAILED  ../patches/arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch

Patching with ../patches/ARM__Allow_to_enable_RT.patch...
SUCCESS

Patching with ../patches/arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch...
SUCCESS

Patching with ../patches/ARM__enable_irq_in_translation_section_permission_fault_handlers.patch...
SUCCESS

Patching with ../patches/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch...
SUCCESS

Patching with ../patches/POWERPC__Allow_to_enable_RT.patch...
SUCCESS

Patching with ../patches/powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch...
SUCCESS

Patching with ../patches/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch...
SUCCESS

Patching with ../patches/powerpc-pseries-Select-the-generic-memory-allocator.patch...
SUCCESS

Patching with ../patches/powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch...
SUCCESS

Patching with ../patches/powerpc__traps__Use_PREEMPT_RT.patch...
SUCCESS

Patching with ../patches/PREEMPT_AUTO.patch...
SUCCESS

Patching with ../patches/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch...
error: patch failed: include/linux/interrupt.h:610
error: include/linux/interrupt.h: patch does not apply
error: patch failed: kernel/softirq.c:620
error: kernel/softirq.c: patch does not apply
FAILED  ../patches/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch

Patching with ../patches/Revert-drm-i915-Depend-on-PREEMPT_RT.patch...
SUCCESS

Patching with ../patches/riscv-add-PREEMPT_AUTO-support.patch...
SUCCESS

Patching with ../patches/riscv-allow-to-enable-RT.patch...
SUCCESS

Patching with ../patches/sched-rt-Don-t-try-push-tasks-if-there-are-none.patch...
SUCCESS

Patching with ../patches/signal_x86__Delay_calling_signals_in_atomic.patch...
error: patch failed: arch/x86/Kconfig:122
error: arch/x86/Kconfig: patch does not apply
error: patch failed: kernel/entry/common.c:139
error: kernel/entry/common.c: patch does not apply
FAILED  ../patches/signal_x86__Delay_calling_signals_in_atomic.patch

Patching with ../patches/softirq-Use-a-dedicated-thread-for-timer-wakeups.patch...
SUCCESS

Patching with ../patches/softirq-Wake-ktimers-thread-also-in-softirq.patch...
SUCCESS

Patching with ../patches/sysfs__Add__sys_kernel_realtime_entry.patch...
SUCCESS

Patching with ../patches/tick-Fix-timer-storm-since-introduction-of-timersd.patch...
error: patch failed: include/linux/interrupt.h:611
error: include/linux/interrupt.h: patch does not apply
error: patch failed: kernel/softirq.c:621
error: kernel/softirq.c: patch does not apply
FAILED  ../patches/tick-Fix-timer-storm-since-introduction-of-timersd.patch

Patching with ../patches/x86__Allow_to_enable_RT.patch...
SUCCESS

Patching with ../patches/x86__Enable_RT_also_on_32bit.patch...
SUCCESS

Patching with ../patches/zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch...
SUCCESS

failed patches: 8

[shuhaowu]

My patch script:

#!/bin/bash

failed=0

cd ./linux
git reset --hard HEAD
git clean -fxd

for p in ../patches/*.patch; do
  echo "Patching with ${p}..."
  git apply --ignore-space-change --ignore-whitespace $p
  if [ "$?" != "0" ]; then
    failed=$((failed + 1))
    echo "FAILED  ${p}"
  else
    echo "SUCCESS"
  fi
  echo
done

echo "failed patches: ${failed}"

the linux directory relative to the script should be cloned from //git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux-raspi/+git/noble on the tag Ubuntu-raspi-6.8.0-1005.5.

The patches directory relative to the script should contain the untar'ed content of patches-6.8.2-rt11.tar.xz

[shuhaowu]

Keep in mind that when Ubuntu says their kernel is "6.8.0", it is not actually. They have their own patches and of course the Linux point release patches are applied as well. To check the Linux point release patches, you can open up the Makefile and check for VERSION PATCHLEVEL SUBLEVEL

[shuhaowu]

@razr also a note: the artifacts on Github actions expires after 90 days.

[shuhaowu]

Think about this a bit more today, it may be nice to maintain a linux kernel tree instead of using scripts to get patches... From that tree we can then generate the patch files.