diff options
Diffstat (limited to 'tools/lib/bpf/bpf_core_read.h')
| -rw-r--r-- | tools/lib/bpf/bpf_core_read.h | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 7325a12692a33..1ce738d91685a 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 <bpf/bpf_helpers.h> + /* * enum bpf_field_info_kind is passed as a second argument into * __builtin_preserve_field_info() built-in to get a specific aspect of @@ -44,7 +46,7 @@ enum bpf_enum_value_kind { #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ #define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ bpf_probe_read_kernel( \ - (void *)dst, \ + (void *)dst, \ __CORE_RELO(src, fld, BYTE_SIZE), \ (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) #else @@ -143,8 +145,29 @@ enum bpf_enum_value_kind { } \ }) +/* Differentiator between compilers builtin implementations. This is a + * requirement due to the compiler parsing differences where GCC optimizes + * early in parsing those constructs of type pointers to the builtin specific + * type, resulting in not being possible to collect the required type + * information in the builtin expansion. + */ +#ifdef __clang__ +#define ___bpf_typeof(type) ((typeof(type) *) 0) +#else +#define ___bpf_typeof1(type, NR) ({ \ + extern typeof(type) *___concat(bpf_type_tmp_, NR); \ + ___concat(bpf_type_tmp_, NR); \ +}) +#define ___bpf_typeof(type) ___bpf_typeof1(type, __COUNTER__) +#endif + +#ifdef __clang__ #define ___bpf_field_ref1(field) (field) -#define ___bpf_field_ref2(type, field) (((typeof(type) *)0)->field) +#define ___bpf_field_ref2(type, field) (___bpf_typeof(type)->field) +#else +#define ___bpf_field_ref1(field) (&(field)) +#define ___bpf_field_ref2(type, field) (&(___bpf_typeof(type)->field)) +#endif #define ___bpf_field_ref(args...) \ ___bpf_apply(___bpf_field_ref, ___bpf_narg(args))(args) @@ -194,7 +217,7 @@ enum bpf_enum_value_kind { * BTF. Always succeeds. */ #define bpf_core_type_id_local(type) \ - __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_LOCAL) + __builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_LOCAL) /* * Convenience macro to get BTF type ID of a target kernel's type that matches @@ -204,7 +227,7 @@ enum bpf_enum_value_kind { * - 0, if no matching type was found in a target kernel BTF. */ #define bpf_core_type_id_kernel(type) \ - __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_TARGET) + __builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_TARGET) /* * Convenience macro to check that provided named type @@ -214,7 +237,7 @@ enum bpf_enum_value_kind { * 0, if no matching type is found. */ #define bpf_core_type_exists(type) \ - __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS) + __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_EXISTS) /* * Convenience macro to check that provided named type @@ -224,7 +247,7 @@ enum bpf_enum_value_kind { * 0, if the type does not match any in the target kernel */ #define bpf_core_type_matches(type) \ - __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_MATCHES) + __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_MATCHES) /* * Convenience macro to get the byte size of a provided named type @@ -234,7 +257,7 @@ enum bpf_enum_value_kind { * 0, if no matching type is found. */ #define bpf_core_type_size(type) \ - __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_SIZE) + __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_SIZE) /* * Convenience macro to check that provided enumerator value is defined in @@ -244,8 +267,13 @@ enum bpf_enum_value_kind { * kernel's BTF; * 0, if no matching enum and/or enum value within that enum is found. */ +#ifdef __clang__ #define bpf_core_enum_value_exists(enum_type, enum_value) \ __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS) +#else +#define bpf_core_enum_value_exists(enum_type, enum_value) \ + __builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_EXISTS) +#endif /* * Convenience macro to get the integer value of an enumerator value in @@ -255,8 +283,13 @@ enum bpf_enum_value_kind { * present in target kernel's BTF; * 0, if no matching enum and/or enum value within that enum is found. */ +#ifdef __clang__ #define bpf_core_enum_value(enum_type, enum_value) \ __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE) +#else +#define bpf_core_enum_value(enum_type, enum_value) \ + __builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_VALUE) +#endif /* * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures @@ -268,7 +301,7 @@ enum bpf_enum_value_kind { * a relocation, which records BTF type ID describing root struct/union and an * accessor string which describes exact embedded field that was used to take * an address. See detailed description of this relocation format and - * semantics in comments to struct bpf_field_reloc in libbpf_internal.h. + * semantics in comments to struct bpf_core_relo in include/uapi/linux/bpf.h. * * This relocation allows libbpf to adjust BPF instruction to use correct * actual field offset, based on target kernel BTF type that matches original @@ -292,6 +325,17 @@ 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 |