SMP on Xilinx Zynq

[Maldonado, Sergio E.]

Problem solved.  My MMU configuration did not have the RTEMS workspace memory set with the shared attribute.

Thanks,

Sergio

On Feb 28, 2015, at 1:53 PM, Joel Sherrill <joel.sherrill at OARcorp.com> wrote:

> 
> 
> On February 28, 2015 2:37:32 PM CST, "Maldonado, Sergio E." <smaldona at slac.stanford.edu> wrote:
>> I have CONFIGURE_SMP_MAXIMUM_PROCESSORS set to 2 and defined the symbol
>> bsp_processor_count, also 2.
>> 
>> Sometime last year, I was able to get SMP working with both cores, but
>> I see that the RTEMS code base has advanced significantly since.
> 
> I don't have the hardware and am not in a position to try it on qemu. Hopefully someone with hardware will try it soon.
> 
>> Thanks,
>> 
>> Sergio
>> 
>> On Feb 28, 2015, at 12:27 PM, Joel Sherrill <joel.sherrill at OARcorp.com>
>> wrote:
>> 
>>> 
>>> 
>>> On February 28, 2015 12:38:54 PM CST, "Maldonado, Sergio E."
>> <smaldona at slac.stanford.edu> wrote:
>>>> Hello,
>>>> 
>>>> Attempting to get SMP working on my Xilinx Zynq platform.  
>>>> I'm currently running RTEMS compiled from the head of the git repo
>>>> master branch (as of 2/28/15), so I should have the latest updates.
>>>> 
>>>> The problem I have is that multitasking does not work when both
>> cores
>>>> are enabled.
>>>> 
>>>> I'm looking for some input on what could be going wrong and how to
>> fix
>>>> it.
>>>> 
>>>> Scenario:
>>>> 
>>>> At system boot, I can verify that core 0 completes RTEMS boot_card
>>>> initialization, and starts multitasking.
>>>> However, Core 0 does _not_ execute the Init task entry point and
>>>> instead goes straight to its idle loop.
>>>> 
>>>> Meanwhile, Core 1 starts and executes until it reaches the first
>>>> _CPU_Context_Switch/_CPU_Context_Restore call.
>>>> If I step into Core 1, I can see that it never returns from this
>>>> routine and stays in an infinite loop of the following instructions
>>> 
>>> Did you configure multiple cores? There are SMP specific
>> configuration parameters such as number of cores in the system.
>>> 
>>>> 
>>>> 83		bne	.L_check_thread_dispatch_necessary
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:131
>>>> 131		GET_SELF_CPU_CONTROL	r2, r3
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:134
>>>> 134		ldrb	r4, [r2, #PER_CPU_DISPATCH_NEEDED]
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:135
>>>> 135		cmp	r4, #0
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:136
>>>> 136		beq	.L_check_is_executing
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:80
>>>> 80		add	r3, r1, #ARM_CONTEXT_CONTROL_IS_EXECUTING_OFFSET
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:81
>>>> 81		ldrexb	r4, [r3]
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:82
>>>> 82		cmp	r4, #0
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:83
>>>> 83		bne	.L_check_thread_dispatch_necessary
>>>> (gdb) s
>>>> ?? ()
>>>> at
>>>> 
>> ../../../../../../../../src/c/src/../../cpukit/score/cpu/arm/cpu_asm.S:131
>>>> 131		GET_SELF_CPU_CONTROL	r2, r3
>>>> (gdb) s
>>>> ...
>>>> 
>>>> 
>>>> Consequently, the Init task entry point is never executed by either
>>>> core, and the system does not complete startup.
>>>> 
>>>> Any thoughts on why Core 1 will not complete its transition to
>>>> multitasking?
>>>> 
>>>> Here's a piece of information that might be useful:
>>>> 
>>>> When I configure RTEMS SMP with just 1 processor, the system
>>>> successfully starts multitasking and the Init task entry point
>> _does_
>>>> get executed by Core 0.
>>>> 
>>>> Thank you,
>>>> 
>>>> Sergio Maldonado - SLAC
>>>> 
>>>> _______________________________________________
>>>> users mailing list
>>>> users at rtems.org
>>>> http://lists.rtems.org/mailman/listinfo/users
>>> 
>>> --joel
> 
> --joel