[DOC][PATCH v2] powerpc: Provide initial documentation for PAPR hcalls

[Nicholas Piggin]

Vaibhav Jain's on August 28, 2019 6:27 pm:
> This doc patch provides an initial description of the hcall op-codes
> that are used by Linux kernel running as a guest (LPAR) on top of
> PowerVM or any other sPAPR compliant hyper-visor (e.g qemu).
> 
> Apart from documenting the hcalls the doc-patch also provides a
> rudimentary overview of how hcall ABI, how they are issued with the
> Linux kernel and how information/control flows between the guest and
> hypervisor.
> 
> Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>
> ---
> Change-log:
> 
> v2:
> * Added a section on Register conventions to be followed when invoking
>   hcalls. [Nick]
> * Updated section on HCALL ABI to clarify that byte ordering only
>   matters to in/out values passed by a memory buffer. [Laurent]
> * Updated a code comment in 'exceptions-64s.S' describing hypercall
>   register conventions to point it to 'papr_hcalls.rst' [Nick]

Thanks for that!

Acked-by: Nicholas Piggin <npiggin at gmail.com>