On Fri, Jan 24, 2025 at 03:27:06PM +0100, David Marchand wrote:
> On Tue, Dec 10, 2024 at 5:33 PM Andre Muezerie
> <andre...@linux.microsoft.com> wrote:
> >
> > MSVC does not support inline assembly, which is used by the
> > implementation of rte_atomic128_cmp_exchange and is needed
> > by lib/stack.
> >
> > Error printed by MSVC:
> >
> > stack_rte_stack_lf.c.obj : error LNK2019:
> > unresolved external symbol rte_atomic128_cmp_exchange referenced
> > in function __rte_stack_lf_push_elems
> >
> > Fix is to provide an implementation for rte_atomic128_cmp_exchange
> > which uses an intrinsic function, which is used when compiling with
> > MSVC. For other compilers the existing implementation continues to
> > be used.
> >
> > Signed-off-by: Andre Muezerie <andre...@linux.microsoft.com>
> > ---
> > lib/eal/x86/include/rte_atomic.h | 4 ++--
> > lib/eal/x86/include/rte_atomic_64.h | 18 ++++++++++++++++++
> > 2 files changed, 20 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/eal/x86/include/rte_atomic.h
> > b/lib/eal/x86/include/rte_atomic.h
> > index c72c47c83e..e8e0e4c33c 100644
> > --- a/lib/eal/x86/include/rte_atomic.h
> > +++ b/lib/eal/x86/include/rte_atomic.h
> > @@ -288,12 +288,12 @@ static inline int
> > rte_atomic32_dec_and_test(rte_atomic32_t *v)
> >
> > #endif
> >
> > +#endif /* RTE_TOOLCHAIN_MSVC */
> > +
> > #ifdef RTE_ARCH_I686
> > #include "rte_atomic_32.h"
> > #else
> > #include "rte_atomic_64.h"
> > #endif
> >
> > -#endif
> > -
>
> This partially reverts 27da6a123414 ("eal: hide legacy atomics API for MSVC").
> It would be better to implement an equivalent to
> rte_atomic128_cmp_exchange in the DPDK "new" stdatomic API
> (rte_stdatomic.h).
>
>
> --
> David Marchand
Thanks for calling that out. After looking at the past commits I got a better
understanding
of the reasons the atomic-related code is laid out the way it is, and I agree
that we should
attempt to follow the same guidelines.
For that reason I changed the approach taken in the v2 I sent out today.
Let me know your thoughts.
--
Andre Muezerie
