AW: SMP for pc686 BSP

Sebastian Huber sebastian.huber at
Fri May 17 04:59:35 UTC 2019

On 17/05/2019 04:26, Chris Johns wrote:
>> Is it this ticket?:
>> I looked at the changes from Sebastian and updated the cpu_asm.S to be more close to the one of the ARM architecture.
>> I haven't been able to test that in detail yet, because some troubles in getting the APs to properly boot.
>> For me the biggest open question atm is 3.) regarding what to do with the GDTs. At the moment I lean towards option 3b and adding the information to the per_CPU structure, because it seems pretty easy.
>> In common setups this would increase the structure by 48 bytes additional space (8 bytes for NULL, text, data, gs and 2 user sections).
>> Would that be a problem?
> Does cpukit/include/rtems/score/percpudata.h help?
> I am not sure how this is put together but the comments at the top of the file
> seem to indicate this exists for this type of purpose. It looks pretty neat.

Optional components should use the <rtems/score/percpudata.h> API for 
per-processor data. Per-processor data required by the CPU port should 
use CPU_Per_CPU_control defined in <rtems/score/cpuimpl.h>. See arm, 
riscv and sparc for examples.

Sebastian Huber, embedded brains GmbH

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