L4Linux stop at "Calibrating delay loop ..."

Reinier Millo Sánchez rmillo at uclv.cu
Thu Sep 22 17:33:16 CEST 2016


We had a similar problem working with Fiasco.OC and GendodeOS on 
ODROID-X2 (Exynos4412) platform. In this case after the review of 
GenodeOS and Fiasco.OC, we identified a small problem in the TrustZone 
implementation, where interrupts remain disabled.

Perhaps this is not the same problem but it can help.


Best regards

On 09/22/2016 10:32 AM, li94575 wrote:
> Hi, adam
> >On Mon Sep 19, 2016 at 22:55:52 +0800, li94575 wrote:
> >>     I compiled the l4re-snapshot-2014092821 with the default modules.list, and everything seems goes
> >> well. However, L4Linux would stop at "Calibrating delay loop ...", because the value of jiffies did not change.
> >> Timer thread has not generate soft interrupt? If I entered jdb via ESC at this time, and quit via "g", then
> >> l4linux can run again. It makes me confused so much.
> >>     Any help or suggestion will be very welcome.
> >
> >This behavior typically indicates that there's an issue with Fiasco's
> >timer interrupt or with the user-level one in L4Linux.
> >For a start you could add e.g. a printk(".\n") in timer_thread in
> >arch/l4/kernel/timer.c to see if it really does something.
> >Does 'hello' work?
> >Although it's a bit of work you could also compare the code of your
> >snapshot and a recent one if there's any significant change (i.e. fix)
> >that might be relevant. Check arch/l4/kernel/timer.c
> >and src/kern/arm/timer-arm-generic.cpp and
> >src/kern/arm/generic_timer.cpp in the Fiasco kernel.
> 'Hello' can work well, which prints "Hello World!" circularly. I add 
> printk(".\n") in timer_thread in
> arch/l4/kernel/timer.c, and found timer_thread stop at 
> l4_ipc_reply_and_wait(u, t, &l, to) after
> initializing the variable ‘increment’. However, if I use LOG_printf() 
> for printing, the phenomenon
> is different, that timer_thread trigers a soft interrupt once. I have 
> checked src/kern/arm/timer-arm-generic.cpp
> and src/kern/arm/generic_timer.cpp in the Fiasco kernel, there is less 
> likely to be a problem with them.
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MsC. Reinier Millo Sánchez
Centro de Estudios de Informática
Universidad Central "Marta Abreu" de Las Villas
Carretera a Camajuaní Km 5 1/2
Santa Clara, Villa Clara, Cuba
CP 54830

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