Re: [PATCH bpf-next v1 7/8] bpf: Propagate bpf_per_cpu_ptr() to /tools

[Yonghong Song]

On 8/19/20 3:40 PM, Hao Luo wrote:
> Sync tools/include/linux/uapi/bpf.h with include/linux/uapi/bpf.h

This can be folded into the previous patch.

> Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>
> ---
>   tools/include/uapi/linux/bpf.h | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 468376f2910b..7e3dfb2bbb86 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -3415,6 +3415,20 @@ union bpf_attr {
>    *		A non-negative value equal to or less than *size* on success,
>    *		or a negative error in case of failure.
>    *
> + * void *bpf_per_cpu_ptr(const void *ptr, u32 cpu)
> + *	Description
> + *		Take the address of a percpu ksym and return a pointer pointing
> + *		to the variable on *cpu*. A ksym is an extern variable decorated
> + *		with '__ksym'. A ksym is percpu if there is a global percpu var
> + *		(either static or global) defined of the same name in the kernel.
> + *
> + *		bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
> + *		kernel, except that bpf_per_cpu_ptr() may return NULL. This
> + *		happens if *cpu* is larger than nr_cpu_ids. The caller of
> + *		bpf_per_cpu_ptr() must check the returned value.
> + *	Return
> + *		A generic pointer pointing to the variable on *cpu*.
> + *
>    */
>   #define __BPF_FUNC_MAPPER(FN)		\
>   	FN(unspec),			\
> @@ -3559,6 +3573,7 @@ union bpf_attr {
>   	FN(skc_to_tcp_request_sock),	\
>   	FN(skc_to_udp6_sock),		\
>   	FN(get_task_stack),		\
> +	FN(bpf_per_cpu_ptr),		\
>   	/* */
>   
>   /* integer value in 'imm' field of BPF_CALL instruction selects which helper