linux-kernel - [PATCH bpf-next v1 7/8] bpf: Propagate bpf_per_cpu

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Date:   Wed, 19 Aug 2020 15:40:29 -0700
From:   Hao Luo <haoluo@...gle.com>
To:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Cc:     Shuah Khan <shuah@...nel.org>, Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andriin@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Quentin Monnet <quentin@...valent.com>,
        Hao Luo <haoluo@...gle.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>, Andrey Ignatov <rdna@...com>,
        Jakub Sitnicki <jakub@...udflare.com>
Subject: [PATCH bpf-next v1 7/8] bpf: Propagate bpf_per_cpu_ptr() to /tools

Sync tools/include/linux/uapi/bpf.h with include/linux/uapi/bpf.h

Signed-off-by: Hao Luo <haoluo@...gle.com>
---
 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
-- 
2.28.0.220.ged08abb693-goog