Dear RT folks!
I'm pleased to announce the v5.0.3-rt1 patch set.
Changes since v4.19.25-rt16:
- rebase to v5.0
- Several ARM architectures have a so called "boot_lock" in their SMP
bring up code. In previous releases the boot_lock was converted to
to a raw_spinlock in order to get in working on -RT. As of v5.0 only the
bits for the `versatile' platform have been applied upstream and I
dropped the patch entirely.
The other platforms were rejected because they were doing it wrong by
using such a lock. The omap2 and sti platform were converted to other
mechanism as part of the discussion. Others (like i.MX) were never
using such a lock.
There are still a few platforms using such a lock. If you are
affected you would to convince the platform maintainer to remove the
lock from the SMP code.
- Applied John Ogness' prinkt rework. One visible change is the
output during boot. Under the hood and for RT: By default, output
that is created at KERN_WARN[0] or higher is printed immediately if the
console supports "atomic" print (currently the 8250 driver does).
This output is printed immediately (and visible) even from IRQ-off
or preempt-disabled regions which wasn't the case earlier. This will
raise the latency at run-time *but* there should be no WARNING,
ERROR or PANIC messages at run-time on a fully working system.
Messages with lower severity are printed "later" by a kthread.
[0] default message level, default_message_loglevel, second field in
/proc/sys/kernel/printk
- Applied "restore FPU on return to userland" series. This only
applies to x86. This change makes repeated kernel_fpu_begin() +
kernel_fpu_end() cheap.
- I tried to include some BH related rework but it is not yet in
reasonable shape. I will probably revisit this during the v5.0
cycle.
Known issues
- A warning triggered in "rcu_note_context_switch" originated from
SyS_timer_gettime(). The issue was always there, it is now
visible. Reported by Grygorii Strashko and Daniel Wagner.
- rcutorture is currently broken on -RT. Reported by Juri Lelli.
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.0.3-rt1
The RT patch against v5.0.3 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patch-5.0.3-rt1.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.3-rt1.tar.xz
Sebastian
