bpf: Introduce bpf_per_cpu_ptr() (eaa6bcb7) · Commits · 戴 / test

include/linux/bpf.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -293,6 +293,7 @@ enum bpf_arg_type {
		ARG_PTR_TO_ALLOC_MEM_OR_NULL, /* pointer to dynamically allocated memory or NULL */
		ARG_CONST_ALLOC_SIZE_OR_ZERO, /* number of allocated bytes requested */
		ARG_PTR_TO_BTF_ID_SOCK_COMMON, /* pointer to in-kernel sock_common or bpf-mirrored bpf_sock */
		ARG_PTR_TO_PERCPU_BTF_ID, /* pointer to in-kernel percpu type */
		__BPF_ARG_TYPE_MAX,
		};

		@@ -307,6 +308,7 @@ enum bpf_return_type {
		RET_PTR_TO_SOCK_COMMON_OR_NULL, /* returns a pointer to a sock_common or NULL */
		RET_PTR_TO_ALLOC_MEM_OR_NULL, /* returns a pointer to dynamically allocated memory or NULL */
		RET_PTR_TO_BTF_ID_OR_NULL, /* returns a pointer to a btf_id or NULL */
		RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL, /* returns a pointer to a valid memory or a btf_id or NULL */
		};

		/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
		@@ -405,6 +407,7 @@ enum bpf_reg_type {
		PTR_TO_RDONLY_BUF_OR_NULL, /* reg points to a readonly buffer or NULL */
		PTR_TO_RDWR_BUF, /* reg points to a read/write buffer */
		PTR_TO_RDWR_BUF_OR_NULL, /* reg points to a read/write buffer or NULL */
		PTR_TO_PERCPU_BTF_ID, /* reg points to a percpu kernel variable */
		};

		/* The information passed from prog-specific *_is_valid_access
		@@ -1828,6 +1831,7 @@ extern const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto;
		extern const struct bpf_func_proto bpf_skc_to_udp6_sock_proto;
		extern const struct bpf_func_proto bpf_copy_from_user_proto;
		extern const struct bpf_func_proto bpf_snprintf_btf_proto;
		extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;

		const struct bpf_func_proto *bpf_tracing_func_proto(
		enum bpf_func_id func_id, const struct bpf_prog *prog);

include/linux/btf.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -110,6 +110,11 @@ btf_resolve_size(const struct btf btf, const struct btf_type type,
		i < btf_type_vlen(struct_type); \
		i++, member++)

		#define for_each_vsi(i, datasec_type, member) \
		for (i = 0, member = btf_type_var_secinfo(datasec_type); \
		i < btf_type_vlen(datasec_type); \
		i++, member++)

		static inline bool btf_type_is_ptr(const struct btf_type *t)
		{
		return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
		@@ -194,6 +199,12 @@ static inline const struct btf_member btf_type_member(const struct btf_type t)
		return (const struct btf_member *)(t + 1);
		}

		static inline const struct btf_var_secinfo *btf_type_var_secinfo(
		const struct btf_type *t)
		{
		return (const struct btf_var_secinfo *)(t + 1);
		}

		#ifdef CONFIG_BPF_SYSCALL
		const struct btf_type btf_type_by_id(const struct btf btf, u32 type_id);
		const char btf_name_by_offset(const struct btf btf, u32 offset);

include/uapi/linux/bpf.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -3686,6 +3686,23 @@ union bpf_attr {
		* Return
		* The helper returns TC_ACT_REDIRECT on success or
		* TC_ACT_SHOT on error.
		*
		* void bpf_per_cpu_ptr(const void percpu_ptr, u32 cpu)
		* Description
		* Take a pointer to a percpu ksym, percpu_ptr, and return a
		* pointer to the percpu kernel variable on cpu. A ksym is an
		* extern variable decorated with '__ksym'. For ksym, there is a
		* global var (either static or global) defined of the same name
		* in the kernel. The ksym is percpu if the global var is percpu.
		* The returned pointer points to the global percpu var on cpu.
		*
		* 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 pointer pointing to the kernel percpu variable on cpu, or
		* NULL, if cpu is invalid.
		*/
		#define __BPF_FUNC_MAPPER(FN) \
		FN(unspec), \
		@@ -3841,6 +3858,7 @@ union bpf_attr {
		FN(seq_printf_btf), \
		FN(skb_cgroup_classid), \
		FN(redirect_neigh), \
		FN(bpf_per_cpu_ptr), \
		/* */

		/* integer value in 'imm' field of BPF_CALL instruction selects which helper

kernel/bpf/btf.c

+0 −10

Original line number	Diff line number	Diff line
		@@ -188,11 +188,6 @@
		i < btf_type_vlen(struct_type); \
		i++, member++)

		#define for_each_vsi(i, struct_type, member) \
		for (i = 0, member = btf_type_var_secinfo(struct_type); \
		i < btf_type_vlen(struct_type); \
		i++, member++)

		#define for_each_vsi_from(i, from, struct_type, member) \
		for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
		i < btf_type_vlen(struct_type); \
		@@ -598,11 +593,6 @@ static const struct btf_var btf_type_var(const struct btf_type t)
		return (const struct btf_var *)(t + 1);
		}

		static const struct btf_var_secinfo btf_type_var_secinfo(const struct btf_type t)
		{
		return (const struct btf_var_secinfo *)(t + 1);
		}

		static const struct btf_kind_operations btf_type_ops(const struct btf_type t)
		{
		return kind_ops[BTF_INFO_KIND(t->info)];

kernel/bpf/helpers.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -623,6 +623,22 @@ const struct bpf_func_proto bpf_copy_from_user_proto = {
		.arg3_type = ARG_ANYTHING,
		};

		BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
		{
		if (cpu >= nr_cpu_ids)
		return (unsigned long)NULL;

		return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
		}

		const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
		.func = bpf_per_cpu_ptr,
		.gpl_only = false,
		.ret_type = RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL,
		.arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
		.arg2_type = ARG_ANYTHING,
		};

		const struct bpf_func_proto bpf_get_current_task_proto __weak;
		const struct bpf_func_proto bpf_probe_read_user_proto __weak;
		const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
		@@ -689,6 +705,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
		return &bpf_snprintf_btf_proto;
		case BPF_FUNC_jiffies64:
		return &bpf_jiffies64_proto;
		case BPF_FUNC_bpf_per_cpu_ptr:
		return &bpf_per_cpu_ptr_proto;
		default:
		break;
		}

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