[RFC,v2,0/6] Deduplicating RISCV cmpxchg.h macros

Message

Leonardo Bras March 21, 2023, 6:34 a.m. UTC

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 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 | 316 +++++++------------------------
 1 file changed, 64 insertions(+), 252 deletions(-)

Comments

Leonardo Bras March 21, 2023, 7:44 a.m. UTC | #1

On Tue, 2023-03-21 at 03:34 -0300, Leonardo Bras 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 
> 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 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 | 316 +++++++------------------------
>  1 file changed, 64 insertions(+), 252 deletions(-)
> 

Re-sending, since it seems to have not worked with patchwork properly.