diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 5aec301e9585..0d3e88bd7d5f 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -2,6 +2,8 @@ #ifndef __BPF_CORE_READ_H__ #define __BPF_CORE_READ_H__ +#include + /* * enum bpf_field_info_kind is passed as a second argument into * __builtin_preserve_field_info() built-in to get a specific aspect of @@ -292,6 +294,17 @@ enum bpf_enum_value_kind { #define bpf_core_read_user_str(dst, sz, src) \ bpf_probe_read_user_str(dst, sz, (const void *)__builtin_preserve_access_index(src)) +extern void *bpf_rdonly_cast(const void *obj, __u32 btf_id) __ksym __weak; + +/* + * Cast provided pointer *ptr* into a pointer to a specified *type* in such + * a way that BPF verifier will become aware of associated kernel-side BTF + * type. This allows to access members of kernel types directly without the + * need to use BPF_CORE_READ() macros. + */ +#define bpf_core_cast(ptr, type) \ + ((typeof(type) *)bpf_rdonly_cast((ptr), bpf_core_type_id_kernel(type))) + #define ___concat(a, b) a ## b #define ___apply(fn, n) ___concat(fn, n) #define ___nth(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, __11, N, ...) N diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h index 23c24f852f4f..0cd4111f954c 100644 --- a/tools/testing/selftests/bpf/bpf_kfuncs.h +++ b/tools/testing/selftests/bpf/bpf_kfuncs.h @@ -63,7 +63,7 @@ extern int bpf_sk_assign_tcp_reqsk(struct __sk_buff *skb, struct sock *sk, void *bpf_cast_to_kern_ctx(void *) __ksym; -void *bpf_rdonly_cast(void *obj, __u32 btf_id) __ksym; +extern void *bpf_rdonly_cast(const void *obj, __u32 btf_id) __ksym __weak; extern int bpf_get_file_xattr(struct file *file, const char *name, struct bpf_dynptr *value_ptr) __ksym; diff --git a/tools/testing/selftests/bpf/progs/sk_storage_omem_uncharge.c b/tools/testing/selftests/bpf/progs/sk_storage_omem_uncharge.c index 3e745793b27a..934c4e5ada5b 100644 --- a/tools/testing/selftests/bpf/progs/sk_storage_omem_uncharge.c +++ b/tools/testing/selftests/bpf/progs/sk_storage_omem_uncharge.c @@ -12,8 +12,6 @@ int cookie_found = 0; __u64 cookie = 0; __u32 omem = 0; -void *bpf_rdonly_cast(void *, __u32) __ksym; - struct { __uint(type, BPF_MAP_TYPE_SK_STORAGE); __uint(map_flags, BPF_F_NO_PREALLOC); diff --git a/tools/testing/selftests/bpf/progs/type_cast.c b/tools/testing/selftests/bpf/progs/type_cast.c index a9629ac230fd..98ab35893f51 100644 --- a/tools/testing/selftests/bpf/progs/type_cast.c +++ b/tools/testing/selftests/bpf/progs/type_cast.c @@ -4,6 +4,7 @@ #include #include #include +#include "bpf_kfuncs.h" struct { __uint(type, BPF_MAP_TYPE_TASK_STORAGE); @@ -19,9 +20,6 @@ char name[IFNAMSIZ]; unsigned int inum; unsigned int meta_len, frag0_len, kskb_len, kskb2_len; -void *bpf_cast_to_kern_ctx(void *) __ksym; -void *bpf_rdonly_cast(void *, __u32) __ksym; - SEC("?xdp") int md_xdp(struct xdp_md *ctx) {