[RFC PATCH v1 0/2] Deduplicating RISCV cmpxchg.h macros

Leonardo Brás leobras at redhat.com
Wed Aug 2 14:51:47 PDT 2023


On Thu, 2023-04-06 at 19:19 +0200, Andrea Parri wrote:
> On Thu, Apr 06, 2023 at 05:20:17AM -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.
> > 
> > Thanks!
> > Leo
> > 
> > Changes since RFCv3:
> > - Squashed the 6 original patches in 2: one for cmpxchg and one for xchg
> > https://lore.kernel.org/all/20230404163741.2762165-1-leobras@redhat.com/
> > 
> > Changes since RFCv2:
> > - 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
> > https://lore.kernel.org/all/20230321074249.2221674-1-leobras@redhat.com/
> > 
> > Changes since RFCv1:
> > - Fixed patch 4/6 suffix from 'w.aqrl' to '.w.aqrl', to avoid build error
> > https://lore.kernel.org/all/20230318080059.1109286-1-leobras@redhat.com/
> > 
> > Leonardo Bras (2):
> >   riscv/cmpxchg: Deduplicate cmpxchg() asm and macros
> >   riscv/cmpxchg: Deduplicate xchg() asm functions
> > 
> >  arch/riscv/include/asm/cmpxchg.h | 319 +++++++------------------------
> >  1 file changed, 67 insertions(+), 252 deletions(-)
> 
> LGTM.  AFAICT, this would need to be rebased, cf. e.g.
> 
>   a8596dda1fbf7e ("arch: rename all internal names __xchg to __arch_xchg")
> 
> from the tip tree.
> 
>   Andrea

Thanks for the heads up!
I will update this and re-send!


And sorry about the delay :(
For some weird reason neither the cover letter, nor your message reached my
gmail, and just now looking at lore I could find your message. 





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