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Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r--kernel/bpf/btf.c145
1 files changed, 142 insertions, 3 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 12361d7b2498..c0d73d71c539 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3205,9 +3205,15 @@ enum {
struct btf_field_info {
enum btf_field_type type;
u32 off;
- struct {
- u32 type_id;
- } kptr;
+ union {
+ struct {
+ u32 type_id;
+ } kptr;
+ struct {
+ const char *node_name;
+ u32 value_btf_id;
+ } list_head;
+ };
};
static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
@@ -3261,6 +3267,63 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
return BTF_FIELD_FOUND;
}
+static const char *btf_find_decl_tag_value(const struct btf *btf,
+ const struct btf_type *pt,
+ int comp_idx, const char *tag_key)
+{
+ int i;
+
+ for (i = 1; i < btf_nr_types(btf); i++) {
+ const struct btf_type *t = btf_type_by_id(btf, i);
+ int len = strlen(tag_key);
+
+ if (!btf_type_is_decl_tag(t))
+ continue;
+ if (pt != btf_type_by_id(btf, t->type) ||
+ btf_type_decl_tag(t)->component_idx != comp_idx)
+ continue;
+ if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
+ continue;
+ return __btf_name_by_offset(btf, t->name_off) + len;
+ }
+ return NULL;
+}
+
+static int btf_find_list_head(const struct btf *btf, const struct btf_type *pt,
+ const struct btf_type *t, int comp_idx,
+ u32 off, int sz, struct btf_field_info *info)
+{
+ const char *value_type;
+ const char *list_node;
+ s32 id;
+
+ if (!__btf_type_is_struct(t))
+ return BTF_FIELD_IGNORE;
+ if (t->size != sz)
+ return BTF_FIELD_IGNORE;
+ value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
+ if (!value_type)
+ return -EINVAL;
+ list_node = strstr(value_type, ":");
+ if (!list_node)
+ return -EINVAL;
+ value_type = kstrndup(value_type, list_node - value_type, GFP_KERNEL | __GFP_NOWARN);
+ if (!value_type)
+ return -ENOMEM;
+ id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
+ kfree(value_type);
+ if (id < 0)
+ return id;
+ list_node++;
+ if (str_is_empty(list_node))
+ return -EINVAL;
+ info->type = BPF_LIST_HEAD;
+ info->off = off;
+ info->list_head.value_btf_id = id;
+ info->list_head.node_name = list_node;
+ return BTF_FIELD_FOUND;
+}
+
static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
int *align, int *sz)
{
@@ -3284,6 +3347,12 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
goto end;
}
}
+ if (field_mask & BPF_LIST_HEAD) {
+ if (!strcmp(name, "bpf_list_head")) {
+ type = BPF_LIST_HEAD;
+ goto end;
+ }
+ }
/* Only return BPF_KPTR when all other types with matchable names fail */
if (field_mask & BPF_KPTR) {
type = BPF_KPTR_REF;
@@ -3339,6 +3408,12 @@ static int btf_find_struct_field(const struct btf *btf,
if (ret < 0)
return ret;
break;
+ case BPF_LIST_HEAD:
+ ret = btf_find_list_head(btf, t, member_type, i, off, sz,
+ idx < info_cnt ? &info[idx] : &tmp);
+ if (ret < 0)
+ return ret;
+ break;
default:
return -EFAULT;
}
@@ -3393,6 +3468,12 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
if (ret < 0)
return ret;
break;
+ case BPF_LIST_HEAD:
+ ret = btf_find_list_head(btf, var, var_type, -1, off, sz,
+ idx < info_cnt ? &info[idx] : &tmp);
+ if (ret < 0)
+ return ret;
+ break;
default:
return -EFAULT;
}
@@ -3491,11 +3572,52 @@ end_btf:
return ret;
}
+static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
+ struct btf_field_info *info)
+{
+ const struct btf_type *t, *n = NULL;
+ const struct btf_member *member;
+ u32 offset;
+ int i;
+
+ t = btf_type_by_id(btf, info->list_head.value_btf_id);
+ /* We've already checked that value_btf_id is a struct type. We
+ * just need to figure out the offset of the list_node, and
+ * verify its type.
+ */
+ for_each_member(i, t, member) {
+ if (strcmp(info->list_head.node_name, __btf_name_by_offset(btf, member->name_off)))
+ continue;
+ /* Invalid BTF, two members with same name */
+ if (n)
+ return -EINVAL;
+ n = btf_type_by_id(btf, member->type);
+ if (!__btf_type_is_struct(n))
+ return -EINVAL;
+ if (strcmp("bpf_list_node", __btf_name_by_offset(btf, n->name_off)))
+ return -EINVAL;
+ offset = __btf_member_bit_offset(n, member);
+ if (offset % 8)
+ return -EINVAL;
+ offset /= 8;
+ if (offset % __alignof__(struct bpf_list_node))
+ return -EINVAL;
+
+ field->list_head.btf = (struct btf *)btf;
+ field->list_head.value_btf_id = info->list_head.value_btf_id;
+ field->list_head.node_offset = offset;
+ }
+ if (!n)
+ return -ENOENT;
+ return 0;
+}
+
struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
u32 field_mask, u32 value_size)
{
struct btf_field_info info_arr[BTF_FIELDS_MAX];
struct btf_record *rec;
+ u32 next_off = 0;
int ret, i, cnt;
ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
@@ -3517,6 +3639,11 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type
ret = -EFAULT;
goto end;
}
+ if (info_arr[i].off < next_off) {
+ ret = -EEXIST;
+ goto end;
+ }
+ next_off = info_arr[i].off + btf_field_type_size(info_arr[i].type);
rec->field_mask |= info_arr[i].type;
rec->fields[i].offset = info_arr[i].off;
@@ -3539,12 +3666,24 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type
if (ret < 0)
goto end;
break;
+ case BPF_LIST_HEAD:
+ ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
+ if (ret < 0)
+ goto end;
+ break;
default:
ret = -EFAULT;
goto end;
}
rec->cnt++;
}
+
+ /* bpf_list_head requires bpf_spin_lock */
+ if (btf_record_has_field(rec, BPF_LIST_HEAD) && rec->spin_lock_off < 0) {
+ ret = -EINVAL;
+ goto end;
+ }
+
return rec;
end:
btf_record_free(rec);
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2025-02-04 22:59:01 +0000