linux.git/arch/parisc/kernel/time.c, branch v7.0

parisc: Detect 64-bit free running platform counter

2026-02-06T23:45:19+00:00

Signed-off-by: Helge Deller

parisc: Convert to generic clockevents

2024-09-09T06:53:17+00:00

Convert parisc timer code to generic clockevents framework.

Signed-off-by: Helge Deller

parisc: Mark cr16 clock unstable on all SMP machines

2022-05-08T18:01:12+00:00

The cr16 interval timers are not synchronized across CPUs, even with just
one dual-core CPU. This becomes visible if the machines have a longer
uptime.

Signed-off-by: Helge Deller

Revert "parisc: Mark sched_clock unstable only if clocks are not syncronized"

2022-05-08T18:01:11+00:00

This reverts commit d97180ad68bdb7ee10f327205a649bc2f558741d.

It triggers RCU stalls at boot with a 32-bit kernel.

Signed-off-by: Helge Deller 
Noticed-by: John David Anglin 
Cc: stable@vger.kernel.org # v5.15+

Revert "parisc: Mark cr16 CPU clocksource unstable on all SMP machines"

2022-05-08T18:01:11+00:00

This reverts commit afdb4a5b1d340e4afffc65daa21cc71890d7d589.

It triggers RCU stalls at boot with a 32-bit kernel.

Signed-off-by: Helge Deller 
Noticed-by: John David Anglin 
Cc: stable@vger.kernel.org # v5.16+

parisc: Find a new timesync master if current CPU is removed

2022-03-29T19:37:13+00:00

When CPU hotplugging is enabled, the user may want to remove the
current CPU which is providing the timer ticks. If this happens
we need to find a new timesync master.

Signed-off-by: Helge Deller

parisc: Move CPU startup-related functions into .text section

2022-03-29T19:37:12+00:00

If CONFIG_HOTPLUG_CPU is enabled, those functions will be run again
after bootup. So they need to reside in the .text section.

Signed-off-by: Helge Deller

parisc: Mark cr16 CPU clocksource unstable on all SMP machines

2021-12-04T20:36:04+00:00

In commit c8c3735997a3 ("parisc: Enhance detection of synchronous cr16
clocksources") I assumed that CPUs on the same physical core are syncronous.
While booting up the kernel on two different C8000 machines, one with a
dual-core PA8800 and one with a dual-core PA8900 CPU, this turned out to be
wrong. The symptom was that I saw a jump in the internal clocks printed to the
syslog and strange overall behaviour.  On machines which have 4 cores (2
dual-cores) the problem isn't visible, because the current logic already marked
the cr16 clocksource unstable in this case.

This patch now marks the cr16 interval timers unstable if we have more than one
CPU in the system, and it fixes this issue.

Fixes: c8c3735997a3 ("parisc: Enhance detection of synchronous cr16 clocksources")
Signed-off-by: Helge Deller 
Cc:  # v5.15+

parisc: Mark sched_clock unstable only if clocks are not syncronized

2021-09-09T10:44:31+00:00

We check at runtime if the cr16 clocks are stable across CPUs. Only mark
the sched_clock unstable by calling clear_sched_clock_stable() if we
know that we run on a system which isn't syncronized across CPUs.

Signed-off-by: Helge Deller

parisc: use legacy_timer_tick

2020-10-30T20:57:05+00:00

parisc has selected CONFIG_GENERIC_CLOCKEVENTS since commit 43b1f6abd590
("parisc: Switch to generic sched_clock implementation"), but does not
appear to actually be using it, and instead calls the low-level
timekeeping functions directly.

Remove the GENERIC_CLOCKEVENTS select again, and instead convert to
the newly added legacy_timer_tick() helper.

Reviewed-by: Linus Walleij 
Signed-off-by: Arnd Bergmann