[dpdk-dev] [PATCH v5 03/10] eal: add intrinsics support check infrastructure

[David Christensen]

On 10/9/20 9:02 AM, Anatoly Burakov wrote:
> Currently, it is not possible to check support for intrinsics that
> are platform-specific, cannot be abstracted in a generic way, or do not
> have support on all architectures. The CPUID flags can be used to some
> extent, but they are only defined for their platform, while intrinsics
> will be available to all code as they are in generic headers.
> 
> This patch introduces infrastructure to check support for certain
> platform-specific intrinsics, and adds support for checking support for
> IA power management-related intrinsics for UMWAIT/UMONITOR and TPAUSE.
> 
> Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
> ---

... snip ...

> diff --git a/lib/librte_eal/ppc/include/rte_power_intrinsics.h b/lib/librte_eal/ppc/include/rte_power_intrinsics.h
> index 70fd7b094f..d63ad86849 100644
> --- a/lib/librte_eal/ppc/include/rte_power_intrinsics.h
> +++ b/lib/librte_eal/ppc/include/rte_power_intrinsics.h
> @@ -17,6 +17,10 @@ extern "C" {
>   /**
>    * This function is not supported on PPC64.
>    *
> + * @warning It is responsibility of the user to check if this function is
> + *   supported at runtime using `rte_cpu_get_features()` API call. Failing to do
> + *   so may result in an illegal CPU instruction error.
> + *
>    * @param p
>    *   Address to monitor for changes. Must be aligned on an 64-byte boundary.
>    * @param expected_value
> @@ -43,6 +47,10 @@ static inline void rte_power_monitor(const volatile void *p,
>   /**
>    * This function is not supported on PPC64.
>    *
> + * @warning It is responsibility of the user to check if this function is
> + *   supported at runtime using `rte_cpu_get_features()` API call. Failing to do
> + *   so may result in an illegal CPU instruction error.
> + *
>    * @param tsc_timestamp
>    *   Maximum TSC timestamp to wait for.
>    *
> diff --git a/lib/librte_eal/ppc/rte_cpuflags.c b/lib/librte_eal/ppc/rte_cpuflags.c
> index 3bb7563ce9..eee8234384 100644
> --- a/lib/librte_eal/ppc/rte_cpuflags.c
> +++ b/lib/librte_eal/ppc/rte_cpuflags.c
> @@ -108,3 +108,9 @@ rte_cpu_get_flag_name(enum rte_cpu_flag_t feature)
>   		return NULL;
>   	return rte_cpu_feature_table[feature].name;
>   }
> +
> +void
> +rte_cpu_get_intrinsics_support(struct rte_cpu_intrinsics *intrinsics)
> +{
> +	memset(intrinsics, 0, sizeof(*intrinsics));
> +}
> diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
> index a93dea9fe6..ed944f2bd4 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -400,6 +400,7 @@ EXPERIMENTAL {
>   	# added in 20.11
>   	__rte_eal_trace_generic_size_t;
>   	rte_service_lcore_may_be_active;
> +	rte_cpu_get_intrinsics_support;
>   };
> 
>   INTERNAL {

Acked-by: David Christensen <drc at linux.vnet.ibm.com>