Re: [PATCH v1 2/4] s390x: Define the PSW bits

Pierre Morel
2019-11-14T15:25:44Z

On 2019-11-14 09:53, Janosch Frank wrote:
> On 11/14/19 9:40 AM, Pierre Morel wrote:
>> On 2019-11-13 17:05, Janosch Frank wrote:
>>> On 11/13/19 1:23 PM, Pierre Morel wrote:
>>>> Instead of assigning obfuscated masks to the PSW dedicated to the
>>>> exceptions, let's define the masks explicitely, it will clarify the
>>> s/explicitely/explicitly/
>>> Try to break that up into sentences.
>> OK thx
...snip...
>>>> +
>>>> +#define PSW_EXCEPTION_MASK (PSW_MASK_EA|PSW_MASK_BA)
>>> That's not a bit anymore, shouldn't that be in arch_def.h?
>>> Also please add a comment, that this is 64 bit addressing.
>>
>> Don't we use the 64bit architecture only?
> architecture != addressing
> We can do 24 bit addressing on zArch...
> We mostly use ESAME (zArch), but old machines start up in the old mode
> and then we transition to zArch via a SIGP.

Yes, this is done during the first instructions of cstart.S:

- Setting the architecture to 64bit / ESAME using SIGP

- Set addressing mode to 64bit

After that AFAIK we never change the addressing mode.

The definitions in the file are intended for PSW flags which AFAIK are
always 64bits.

I created arch_bits.h to avoid using arch_def.h which contains C
structures and functions, so preventing to include it in assembler files.

Regards,

Pierre

>
>> Regards,
>>
>> Pierre
>>
>>
>
--
Pierre Morel
IBM Lab Boeblingen