Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 22 Mar 2023 01:45:14 +0100 | From | Andrea Parri <> | Subject | Re: [RESEND RFC PATCH v2 1/6] riscv/cmpxchg: Deduplicate cmpxchg() asm functions |
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On Tue, Mar 21, 2023 at 04:42:44AM -0300, Leonardo Bras wrote: > In this header every cmpxchg define (_relaxed, _acquire, _release, > vanilla) contain it's own asm file, both for 4-byte variables an 8-byte > variables, on a total of 8 versions of mostly the same asm. > > This is usually bad, as it means any change may be done in up to 8 > different places. > > Unify those versions by creating a new define with enough parameters to > generate any version of the previous 8. > > (This did not cause any change in generated asm) > > Signed-off-by: Leonardo Bras <leobras@redhat.com> > --- > arch/riscv/include/asm/cmpxchg.h | 102 ++++++++----------------------- > 1 file changed, 24 insertions(+), 78 deletions(-)
Diff looks nice,
> +#define ___cmpxchg(lr_sfx, sc_sfx, prepend, append) \ > +{ \ > + __asm__ __volatile__ ( \ > + prepend \ > + "0: lr" lr_sfx " %0, %2\n" \ > + " bne %0, %z3, 1f\n" \ > + " sc" sc_sfx " %1, %z4, %2\n" \ > + " bnez %1, 0b\n" \ > + append \ > + "1:\n" \ > + : "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \ > + : "rJ" ((long)__old), "rJ" (__new) \ > + : "memory"); \ > +}
Though I'm not really a fan of macros depending on local variables with "magic" names, can this be avoided?
Thanks, Andrea
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