While studying riscv's cmpxchg.h file, I got really interested in 
understanding how RISCV asm implemented the different versions of 
{cmp,}xchg.

When I understood the pattern, it made sense for me to remove the 
duplications and create macros to make it easier to understand what exactly 
changes between the versions: Instruction sufixes & barriers.

I split those changes in 3 levels for each cmpxchg and xchg, resulting a 
total of 6 patches. I did this so it becomes easier to review and remove 
the last levels if desired, but I have no issue squashing them if it's 
better.

Please provide comments.

Thanks!
Leo

Changes since v2:
- Fixed  macros that depend on having a local variable with a magic name
- Previous cast to (long) is now only applied on 4-bytes cmpxchg

Changes since v1:
- Fixed patch 4/6 suffix from 'w.aqrl' to '.w.aqrl', to avoid build error


Leonardo Bras (6):
  riscv/cmpxchg: Deduplicate cmpxchg() asm functions
  riscv/cmpxchg: Deduplicate cmpxchg() macros
  riscv/cmpxchg: Deduplicate arch_cmpxchg() macros
  riscv/cmpxchg: Deduplicate xchg() asm functions
  riscv/cmpxchg: Deduplicate xchg() macros
  riscv/cmpxchg: Deduplicate arch_xchg() macros

 arch/riscv/include/asm/cmpxchg.h | 319 +++++++------------------------
 1 file changed, 67 insertions(+), 252 deletions(-)

-- 
2.40.0

Thx Leonardo,

It's a good point for cleaning up.

On Wed, Apr 5, 2023 at 12:37 AM Leonardo Bras <leobras@redhat.com> wrote:
>
> While studying riscv's cmpxchg.h file, I got really interested in
> understanding how RISCV asm implemented the different versions of
> {cmp,}xchg.
>
> When I understood the pattern, it made sense for me to remove the
> duplications and create macros to make it easier to understand what exactly
> changes between the versions: Instruction sufixes & barriers.
>
> I split those changes in 3 levels for each cmpxchg and xchg, resulting a
But how about merging 3 levels into one? (I mean one for cmpxchg and
one for xchg, resulting in 2 patches.)

> total of 6 patches. I did this so it becomes easier to review and remove
> the last levels if desired, but I have no issue squashing them if it's
> better.
>
> Please provide comments.
>
> Thanks!
> Leo
>
> Changes since v2:
> - Fixed  macros that depend on having a local variable with a magic name
> - Previous cast to (long) is now only applied on 4-bytes cmpxchg
>
> Changes since v1:
> - Fixed patch 4/6 suffix from 'w.aqrl' to '.w.aqrl', to avoid build error
>
>
> Leonardo Bras (6):
>   riscv/cmpxchg: Deduplicate cmpxchg() asm functions
>   riscv/cmpxchg: Deduplicate cmpxchg() macros
>   riscv/cmpxchg: Deduplicate arch_cmpxchg() macros
>   riscv/cmpxchg: Deduplicate xchg() asm functions
>   riscv/cmpxchg: Deduplicate xchg() macros
>   riscv/cmpxchg: Deduplicate arch_xchg() macros
>
>  arch/riscv/include/asm/cmpxchg.h | 319 +++++++------------------------
>  1 file changed, 67 insertions(+), 252 deletions(-)
>
> --
> 2.40.0
>


-- 
Best Regards
 Guo Ren

On Wed, Apr 5, 2023 at 11:40 PM Guo Ren <guoren@kernel.org> wrote:
>
> Thx Leonardo,
>
> It's a good point for cleaning up.

Hello Guo,
Thanks for the feedback!

>
> On Wed, Apr 5, 2023 at 12:37 AM Leonardo Bras <leobras@redhat.com> wrote:
> >
> > While studying riscv's cmpxchg.h file, I got really interested in
> > understanding how RISCV asm implemented the different versions of
> > {cmp,}xchg.
> >
> > When I understood the pattern, it made sense for me to remove the
> > duplications and create macros to make it easier to understand what exactly
> > changes between the versions: Instruction sufixes & barriers.
> >
> > I split those changes in 3 levels for each cmpxchg and xchg, resulting a
> But how about merging 3 levels into one? (I mean one for cmpxchg and
> one for xchg, resulting in 2 patches.)

Sure, as mentioned below, I have no issue squashing the patches, so 2
should work fine.

I was previously worried about the changes, so I split them in 3 so
it's easier to understand my thought process.

I will resend it in a couple minutes.

>
> > total of 6 patches. I did this so it becomes easier to review and remove
> > the last levels if desired, but I have no issue squashing them if it's
> > better.
> >
> > Please provide comments.
> >
> > Thanks!
> > Leo
> >
> > Changes since v2:
> > - Fixed  macros that depend on having a local variable with a magic name
> > - Previous cast to (long) is now only applied on 4-bytes cmpxchg
> >
> > Changes since v1:
> > - Fixed patch 4/6 suffix from 'w.aqrl' to '.w.aqrl', to avoid build error
> >
> >
> > Leonardo Bras (6):
> >   riscv/cmpxchg: Deduplicate cmpxchg() asm functions
> >   riscv/cmpxchg: Deduplicate cmpxchg() macros
> >   riscv/cmpxchg: Deduplicate arch_cmpxchg() macros
> >   riscv/cmpxchg: Deduplicate xchg() asm functions
> >   riscv/cmpxchg: Deduplicate xchg() macros
> >   riscv/cmpxchg: Deduplicate arch_xchg() macros
> >
> >  arch/riscv/include/asm/cmpxchg.h | 319 +++++++------------------------
> >  1 file changed, 67 insertions(+), 252 deletions(-)
> >
> > --
> > 2.40.0
> >
>
>
> --
> Best Regards
>  Guo Ren
>

Best regards,
Leo