diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 673065cf25d0..a9d5b3420b94 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -309,6 +309,7 @@ enum bpf_return_type { 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 */ + RET_PTR_TO_MEM_OR_BTF_ID, /* returns a pointer to a valid memory or a btf_id */ }; /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs @@ -1850,6 +1851,7 @@ 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; +extern const struct bpf_func_proto bpf_this_cpu_ptr_proto; const struct bpf_func_proto *bpf_tracing_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 6d1b8c67b8e5..9dd66e1eeb05 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3713,6 +3713,18 @@ union bpf_attr { * Return * A pointer pointing to the kernel percpu variable on *cpu*, or * NULL, if *cpu* is invalid. + * + * void *bpf_this_cpu_ptr(const void *percpu_ptr) + * Description + * Take a pointer to a percpu ksym, *percpu_ptr*, and return a + * pointer to the percpu kernel variable on this cpu. See the + * description of 'ksym' in **bpf_per_cpu_ptr**\ (). + * + * bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in + * the kernel. Different from **bpf_per_cpu_ptr**\ (), it would + * never return NULL. + * Return + * A pointer pointing to the kernel percpu variable on this cpu. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3869,6 +3881,7 @@ union bpf_attr { FN(skb_cgroup_classid), \ FN(redirect_neigh), \ FN(bpf_per_cpu_ptr), \ + FN(bpf_this_cpu_ptr), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 82a6b9077118..adc434e2a9f7 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -649,6 +649,18 @@ const struct bpf_func_proto bpf_per_cpu_ptr_proto = { .arg2_type = ARG_ANYTHING, }; +BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr) +{ + return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr); +} + +const struct bpf_func_proto bpf_this_cpu_ptr_proto = { + .func = bpf_this_cpu_ptr, + .gpl_only = false, + .ret_type = RET_PTR_TO_MEM_OR_BTF_ID, + .arg1_type = ARG_PTR_TO_PERCPU_BTF_ID, +}; + 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; @@ -717,6 +729,8 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_jiffies64_proto; case BPF_FUNC_bpf_per_cpu_ptr: return &bpf_per_cpu_ptr_proto; + case BPF_FUNC_bpf_this_cpu_ptr: + return &bpf_this_cpu_ptr_proto; default: break; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 98c45a20e284..35ce1f24f88d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5126,7 +5126,8 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn regs[BPF_REG_0].type = PTR_TO_MEM_OR_NULL; regs[BPF_REG_0].id = ++env->id_gen; regs[BPF_REG_0].mem_size = meta.mem_size; - } else if (fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL) { + } else if (fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL || + fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID) { const struct btf_type *t; mark_reg_known_zero(env, regs, BPF_REG_0); @@ -5144,10 +5145,14 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn tname, PTR_ERR(ret)); return -EINVAL; } - regs[BPF_REG_0].type = PTR_TO_MEM_OR_NULL; + regs[BPF_REG_0].type = + fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ? + PTR_TO_MEM : PTR_TO_MEM_OR_NULL; regs[BPF_REG_0].mem_size = tsize; } else { - regs[BPF_REG_0].type = PTR_TO_BTF_ID_OR_NULL; + regs[BPF_REG_0].type = + fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ? + PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL; regs[BPF_REG_0].btf_id = meta.ret_btf_id; } } else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL) { diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 20b987bee098..2d593e5d0360 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1219,6 +1219,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_snprintf_btf_proto; case BPF_FUNC_bpf_per_cpu_ptr: return &bpf_per_cpu_ptr_proto; + case BPF_FUNC_bpf_this_cpu_ptr: + return &bpf_this_cpu_ptr_proto; default: return NULL; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6a1ae3563df2..032605d178ef 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3672,6 +3672,18 @@ union bpf_attr { * Return * A pointer pointing to the kernel percpu variable on *cpu*, or * NULL, if *cpu* is invalid. + * + * void *bpf_this_cpu_ptr(const void *percpu_ptr) + * Description + * Take a pointer to a percpu ksym, *percpu_ptr*, and return a + * pointer to the percpu kernel variable on this cpu. See the + * description of 'ksym' in **bpf_per_cpu_ptr**\ (). + * + * bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in + * the kernel. Different from **bpf_per_cpu_ptr**\ (), it would + * never return NULL. + * Return + * A pointer pointing to the kernel percpu variable on this cpu. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3828,6 +3840,7 @@ union bpf_attr { FN(skb_cgroup_classid), \ FN(redirect_neigh), \ FN(bpf_per_cpu_ptr), \ + FN(bpf_this_cpu_ptr), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper