diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 4fefa27d5aea..5e2b231a9af4 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3442,10 +3442,12 @@ btf_find_graph_root(const struct btf *btf, const struct btf_type *pt, goto end; \ } -static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, +static int btf_get_field_type(const struct btf *btf, const struct btf_type *var_type, + u32 field_mask, u32 *seen_mask, int *align, int *sz) { int type = 0; + const char *name = __btf_name_by_offset(btf, var_type->name_off); if (field_mask & BPF_SPIN_LOCK) { if (!strcmp(name, "bpf_spin_lock")) { @@ -3481,7 +3483,7 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, field_mask_test_name(BPF_REFCOUNT, "bpf_refcount"); /* Only return BPF_KPTR when all other types with matchable names fail */ - if (field_mask & BPF_KPTR) { + if (field_mask & BPF_KPTR && !__btf_type_is_struct(var_type)) { type = BPF_KPTR_REF; goto end; } @@ -3494,41 +3496,83 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, #undef field_mask_test_name -/* Repeat a field for a specified number of times. +/* Repeat a number of fields for a specified number of times. * - * Copy and repeat the first field for repeat_cnt - * times. The field is repeated by adding the offset of each field - * with + * Copy the fields starting from the first field and repeat them for + * repeat_cnt times. The fields are repeated by adding the offset of each + * field with * (i + 1) * elem_size * where i is the repeat index and elem_size is the size of an element. */ -static int btf_repeat_field(struct btf_field_info *info, - u32 repeat_cnt, u32 elem_size) +static int btf_repeat_fields(struct btf_field_info *info, + u32 field_cnt, u32 repeat_cnt, u32 elem_size) { - u32 i; + u32 i, j; u32 cur; /* Ensure not repeating fields that should not be repeated. */ - switch (info[0].type) { - case BPF_KPTR_UNREF: - case BPF_KPTR_REF: - case BPF_KPTR_PERCPU: - case BPF_LIST_HEAD: - case BPF_RB_ROOT: - break; - default: - return -EINVAL; + for (i = 0; i < field_cnt; i++) { + switch (info[i].type) { + case BPF_KPTR_UNREF: + case BPF_KPTR_REF: + case BPF_KPTR_PERCPU: + case BPF_LIST_HEAD: + case BPF_RB_ROOT: + break; + default: + return -EINVAL; + } } - cur = 1; + cur = field_cnt; for (i = 0; i < repeat_cnt; i++) { - memcpy(&info[cur], &info[0], sizeof(info[0])); - info[cur++].off += (i + 1) * elem_size; + memcpy(&info[cur], &info[0], field_cnt * sizeof(info[0])); + for (j = 0; j < field_cnt; j++) + info[cur++].off += (i + 1) * elem_size; } return 0; } +static int btf_find_struct_field(const struct btf *btf, + const struct btf_type *t, u32 field_mask, + struct btf_field_info *info, int info_cnt); + +/* Find special fields in the struct type of a field. + * + * This function is used to find fields of special types that is not a + * global variable or a direct field of a struct type. It also handles the + * repetition if it is the element type of an array. + */ +static int btf_find_nested_struct(const struct btf *btf, const struct btf_type *t, + u32 off, u32 nelems, + u32 field_mask, struct btf_field_info *info, + int info_cnt) +{ + int ret, err, i; + + ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt); + + if (ret <= 0) + return ret; + + /* Shift the offsets of the nested struct fields to the offsets + * related to the container. + */ + for (i = 0; i < ret; i++) + info[i].off += off; + + if (nelems > 1) { + err = btf_repeat_fields(info, ret, nelems - 1, t->size); + if (err == 0) + ret *= nelems; + else + ret = err; + } + + return ret; +} + static int btf_find_field_one(const struct btf *btf, const struct btf_type *var, const struct btf_type *var_type, @@ -3555,8 +3599,18 @@ static int btf_find_field_one(const struct btf *btf, if (nelems == 0) return 0; - field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off), + field_type = btf_get_field_type(btf, var_type, field_mask, seen_mask, &align, &sz); + /* Look into variables of struct types */ + if (!field_type && __btf_type_is_struct(var_type)) { + sz = var_type->size; + if (expected_size && expected_size != sz * nelems) + return 0; + ret = btf_find_nested_struct(btf, var_type, off, nelems, field_mask, + &info[0], info_cnt); + return ret; + } + if (field_type == 0) return 0; if (field_type < 0) @@ -3605,7 +3659,7 @@ static int btf_find_field_one(const struct btf *btf, if (nelems > info_cnt) return -E2BIG; if (nelems > 1) { - ret = btf_repeat_field(info, nelems - 1, sz); + ret = btf_repeat_fields(info, 1, nelems - 1, sz); if (ret < 0) return ret; }