[RFC PATCH v3 0/6] Deduplicating RISCV cmpxchg.h macros

[Leonardo Bras]

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