bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter (35578d79) · Commits · 戴 / test

include/linux/bpf.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -190,6 +190,7 @@ extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
	extern const struct bpf_func_proto bpf_map_update_elem_proto;		extern const struct bpf_func_proto bpf_map_update_elem_proto;
	extern const struct bpf_func_proto bpf_map_delete_elem_proto;		extern const struct bpf_func_proto bpf_map_delete_elem_proto;

			extern const struct bpf_func_proto bpf_perf_event_read_proto;
	extern const struct bpf_func_proto bpf_get_prandom_u32_proto;		extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
	extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;		extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
	extern const struct bpf_func_proto bpf_tail_call_proto;		extern const struct bpf_func_proto bpf_tail_call_proto;

include/uapi/linux/bpf.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -271,6 +271,7 @@ enum bpf_func_id {
	*/		*/
	BPF_FUNC_skb_get_tunnel_key,		BPF_FUNC_skb_get_tunnel_key,
	BPF_FUNC_skb_set_tunnel_key,		BPF_FUNC_skb_set_tunnel_key,
			BPF_FUNC_perf_event_read, /* u64 bpf_perf_event_read(&map, index) */
	__BPF_FUNC_MAX_ID,		__BPF_FUNC_MAX_ID,
	};		};

kernel/bpf/verifier.c

+33 −15

Original line number	Original line	Diff line number	Diff line
	@@ -238,6 +238,14 @@ static const char * const reg_type_str[] = {
	[CONST_IMM] = "imm",		[CONST_IMM] = "imm",
	};		};

			static const struct {
			int map_type;
			int func_id;
			} func_limit[] = {
			{BPF_MAP_TYPE_PROG_ARRAY, BPF_FUNC_tail_call},
			{BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_read},
			};

	static void print_verifier_state(struct verifier_env *env)		static void print_verifier_state(struct verifier_env *env)
	{		{
	enum bpf_reg_type t;		enum bpf_reg_type t;
	@@ -837,6 +845,28 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
	return err;		return err;
	}		}

			static int check_map_func_compatibility(struct bpf_map *map, int func_id)
			{
			bool bool_map, bool_func;
			int i;

			if (!map)
			return 0;

			for (i = 0; i <= ARRAY_SIZE(func_limit); i++) {
			bool_map = (map->map_type == func_limit[i].map_type);
			bool_func = (func_id == func_limit[i].func_id);
			/* only when map & func pair match it can continue.
			* don't allow any other map type to be passed into
			* the special func;
			*/
			if (bool_map != bool_func)
			return -EINVAL;
			}

			return 0;
			}

	static int check_call(struct verifier_env *env, int func_id)		static int check_call(struct verifier_env *env, int func_id)
	{		{
	struct verifier_state *state = &env->cur_state;		struct verifier_state *state = &env->cur_state;
	@@ -912,21 +942,9 @@ static int check_call(struct verifier_env *env, int func_id)
	return -EINVAL;		return -EINVAL;
	}		}

	if (map && map->map_type == BPF_MAP_TYPE_PROG_ARRAY &&		err = check_map_func_compatibility(map, func_id);
	func_id != BPF_FUNC_tail_call)		if (err)
	/* prog_array map type needs extra care:		return err;
	* only allow to pass it into bpf_tail_call() for now.
	* bpf_map_delete_elem() can be allowed in the future,
	* while bpf_map_update_elem() must only be done via syscall
	*/
	return -EINVAL;

	if (func_id == BPF_FUNC_tail_call &&
	map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
	/* don't allow any other map type to be passed into
	* bpf_tail_call()
	*/
	return -EINVAL;

	return 0;		return 0;
	}		}

kernel/trace/bpf_trace.c

+31 −0

Original line number	Original line	Diff line number	Diff line
	@@ -158,6 +158,35 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
	return &bpf_trace_printk_proto;		return &bpf_trace_printk_proto;
	}		}

			static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5)
			{
			struct bpf_map map = (struct bpf_map ) (unsigned long) r1;
			struct bpf_array *array = container_of(map, struct bpf_array, map);
			struct perf_event *event;

			if (unlikely(index >= array->map.max_entries))
			return -E2BIG;

			event = (struct perf_event *)array->ptrs[index];
			if (!event)
			return -ENOENT;

			/*
			* we don't know if the function is run successfully by the
			* return value. It can be judged in other places, such as
			* eBPF programs.
			*/
			return perf_event_read_local(event);
			}

			const struct bpf_func_proto bpf_perf_event_read_proto = {
			.func = bpf_perf_event_read,
			.gpl_only = false,
			.ret_type = RET_INTEGER,
			.arg1_type = ARG_CONST_MAP_PTR,
			.arg2_type = ARG_ANYTHING,
			};

	static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)		static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
	{		{
	switch (func_id) {		switch (func_id) {
	@@ -183,6 +212,8 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func
	return bpf_get_trace_printk_proto();		return bpf_get_trace_printk_proto();
	case BPF_FUNC_get_smp_processor_id:		case BPF_FUNC_get_smp_processor_id:
	return &bpf_get_smp_processor_id_proto;		return &bpf_get_smp_processor_id_proto;
			case BPF_FUNC_perf_event_read:
			return &bpf_perf_event_read_proto;
	default:		default:
	return NULL;		return NULL;
	}		}

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