[PATCH v3 2/3] Add ARM Paravirtualization support

[Sebastian Huber]

----- Am 23. Feb 2018 um 2:32 schrieb Chris Johns chrisj at rtems.org:

> On 22/02/2018 22:39, Sebastian Huber wrote:
>> For the XtratuM support on ARMv7-R I simply built the tools via the RSB and
>> added "-mtp=soft" to the C/C++ flags. I also used "-mtp=soft" for the BSP, this
>> instructs GCC to use calls to __aeabi_read_tp().
> 
> I had no idea this was the case.

This is a workaround for an XtratuM shortcoming. A proper hypervisor would support a hypercall to set the TPIDRURO.

> 
> On ARM or to be more specific on ARM SMP builds the thread ID will have to be
> set to the thread TCB on ARM SMP machines by the context switcher. It is needed
> to support libdebugger on SMP for stepping to work.

This is fine.