Re: [PATCH v2 0/2] target/mips: Add two groups of loongson-ext instructions

[Jiaxun Yang]

在 2020/6/18 20:00, Aleksandar Markovic 写道:
> среда, 17. јун 2020., Jiaxun Yang <jiaxun.yang@flygoat.com 
> <mailto:jiaxun.yang@flygoat.com>> је написао/ла:
>
>
>
>     在 2020/6/16 22:41, Aleksandar Markovic 写道:
>
>
>
>         уторак, 16. јун 2020., Jiaxun Yang <jiaxun.yang@flygoat.com
>         <mailto:jiaxun.yang@flygoat.com> <mailto:jiaxun.yang@flygoat.com
>         <mailto:jiaxun.yang@flygoat.com>>> је написао/ла:
>
>
>
>              在 2020/6/16 18:38, Aleksandar Markovic 写道:
>
>
>
>                  уторак, 16. јун 2020., Jiaxun Yang
>         <jiaxun.yang@flygoat.com <mailto:jiaxun.yang@flygoat.com>
>                  <mailto:jiaxun.yang@flygoat.com
>         <mailto:jiaxun.yang@flygoat.com>>
>         <mailto:jiaxun.yang@flygoat.com <mailto:jiaxun.yang@flygoat.com>
>                  <mailto:jiaxun.yang@flygoat.com
>         <mailto:jiaxun.yang@flygoat.com>>>> је написао/ла:
>
>                       This is the sucessor of:
>                       "Basic TCG Loongson-3A1000 Support"
>
>                       Thanks!
>
>
>                  Hi, Jiaxun.
>
>                  Thanks for providing updated version of the series.
>
>                  I wonder, given so many "#if defined(TARGET_MIPS64)"
>         lines in
>                  this series, what would be the 32-bit processors that
>         support
>                  Loongson EXT ASE?
>
>
>              Loongson GS232 core which can be found in Loongson-1A/B/C
>         should
>              support it.
>              Although I have no intension to work on QEMU support of these
>              processors.
>
>
>         ...And, for the sake of accuracy, you nevertheless included the
>         correct implementation (for both 32-bir and 64-bit). That is
>         very good. I would do the same, if I were you.
>
>         However, there is a problem. We can't upstream (at least not in
>         QEMU for MIPS) anything without the proper documentation.
>
>         So, please provide the links or attach the supporting files to
>         the cover letter in v2. You already did something similar in
>         some of your previous series and patches. I am perfectly fine
>         with machine translation from Chinese.
>
>         For example, you need to provide, among other things, docs
>         describing EXT support in GS 232 cores. We can't just make
>         assumptions, or trust your word. These sources of information
>         should be repeated for all versions (v2, v3,...) of the series,
>         in their cover letters.
>
>
>     I'll attach necessary information about these instructions in next
>     version, however, there is no public document avilable for GS232 core.
>     That's why I'm not intend to upstream it for now.
>
>     Should I keep these code as is? Ot just filter all Loongson EXT out
>     for MIPS32.
>
>
> Sorry for late response, Jiaxun, I got carried away with other things.
>
> I am not sure, I simply don't have access to the appropriate info. at 
> this moment, I'd say you can keep (for now) the "ifdef"-ed code for 
> handling 32-bit, since it will never be actually used.
>
> But, how do you know the code is correct, if there is no doc? How do you 
> know about specifics of 32-bit ext? Is it just guessing, or more than 
> that? Mention the source of information in commit messages, if any. Or  > say this is just a guess.

By guess and experiments on real hardware....

> A short comment should be added about handling for 32-bit just before 
> the main functions that handle Loongson EXT, just like Richard did for 
> those instructions from LMMI that he could not find proper documentation.

Will do.

> Also, can you mention what is achieved by having EXT in QEMU? What 
> Longson-related scenarion would work, that previously (currently) would not?

As most applications targeting Loongson processor including Kernel are 
compiled -march=loongson3a CFLAG, without supoorting these instructions 
these applications can never run properly.

I'll mention them in next version of cover letter. Probably tomorrow.

> Thanks for this nice series, and all valuable efforts, hopefully we will 
> resolve documentation issue in comming days or weeks.

Thanks, and wish you all health!

> Aleksandar
>
>
>
>     Thanks.
>
>
>         I salute your series, but it needs much more justification.
>
>         Yours,
>         Aleksandar
>
>
>                  Thanks,
>                  Aleksandar
>
>                       Jiaxun Yang (2):
>                          target/mips: Add loongson-ext lsdc2 group of
>         instructions
>                          target/mips: Add loongson-ext lswc2 group of
>         instrustions
>
>
>                  Also, a spelling mistake in the second title.
>
>
>              Ahh, My bad....
>
>
>                         target/mips/translate.c | 437
>                  ++++++++++++++++++++++++++++++++++++++++
>                         1 file changed, 437 insertions(+)
>
>                       --     2.27.0.rc2
>
>
>              --     - Jiaxun
>
>
>     -- 
>     - Jiaxun

--
- Jiaxun