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-rw-r--r--include/linux/bpf.h17
-rw-r--r--include/uapi/linux/bpf.h10
-rw-r--r--kernel/bpf/btf.c145
-rw-r--r--kernel/bpf/helpers.c32
-rw-r--r--kernel/bpf/syscall.c22
-rw-r--r--kernel/bpf/verifier.c7
-rw-r--r--tools/include/uapi/linux/bpf.h10
7 files changed, 239 insertions, 4 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f08eb2d27de0..05f98e9e5c48 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -175,6 +175,7 @@ enum btf_field_type {
BPF_KPTR_UNREF = (1 << 2),
BPF_KPTR_REF = (1 << 3),
BPF_KPTR = BPF_KPTR_UNREF | BPF_KPTR_REF,
+ BPF_LIST_HEAD = (1 << 4),
};
struct btf_field_kptr {
@@ -184,11 +185,18 @@ struct btf_field_kptr {
u32 btf_id;
};
+struct btf_field_list_head {
+ struct btf *btf;
+ u32 value_btf_id;
+ u32 node_offset;
+};
+
struct btf_field {
u32 offset;
enum btf_field_type type;
union {
struct btf_field_kptr kptr;
+ struct btf_field_list_head list_head;
};
};
@@ -266,6 +274,8 @@ static inline const char *btf_field_type_name(enum btf_field_type type)
case BPF_KPTR_UNREF:
case BPF_KPTR_REF:
return "kptr";
+ case BPF_LIST_HEAD:
+ return "bpf_list_head";
default:
WARN_ON_ONCE(1);
return "unknown";
@@ -282,6 +292,8 @@ static inline u32 btf_field_type_size(enum btf_field_type type)
case BPF_KPTR_UNREF:
case BPF_KPTR_REF:
return sizeof(u64);
+ case BPF_LIST_HEAD:
+ return sizeof(struct bpf_list_head);
default:
WARN_ON_ONCE(1);
return 0;
@@ -298,6 +310,8 @@ static inline u32 btf_field_type_align(enum btf_field_type type)
case BPF_KPTR_UNREF:
case BPF_KPTR_REF:
return __alignof__(u64);
+ case BPF_LIST_HEAD:
+ return __alignof__(struct bpf_list_head);
default:
WARN_ON_ONCE(1);
return 0;
@@ -403,6 +417,9 @@ static inline void zero_map_value(struct bpf_map *map, void *dst)
void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
bool lock_src);
void bpf_timer_cancel_and_free(void *timer);
+void bpf_list_head_free(const struct btf_field *field, void *list_head,
+ struct bpf_spin_lock *spin_lock);
+
int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size);
struct bpf_offload_dev;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index fb4c911d2a03..6580448e9f77 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6888,6 +6888,16 @@ struct bpf_dynptr {
__u64 :64;
} __attribute__((aligned(8)));
+struct bpf_list_head {
+ __u64 :64;
+ __u64 :64;
+} __attribute__((aligned(8)));
+
+struct bpf_list_node {
+ __u64 :64;
+ __u64 :64;
+} __attribute__((aligned(8)));
+
struct bpf_sysctl {
__u32 write; /* Sysctl is being read (= 0) or written (= 1).
* Allows 1,2,4-byte read, but no write.
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);
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 283f55bbeb70..7bc71995f17c 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1706,6 +1706,38 @@ bpf_base_func_proto(enum bpf_func_id func_id)
}
}
+void bpf_list_head_free(const struct btf_field *field, void *list_head,
+ struct bpf_spin_lock *spin_lock)
+{
+ struct list_head *head = list_head, *orig_head = list_head;
+
+ BUILD_BUG_ON(sizeof(struct list_head) > sizeof(struct bpf_list_head));
+ BUILD_BUG_ON(__alignof__(struct list_head) > __alignof__(struct bpf_list_head));
+
+ /* Do the actual list draining outside the lock to not hold the lock for
+ * too long, and also prevent deadlocks if tracing programs end up
+ * executing on entry/exit of functions called inside the critical
+ * section, and end up doing map ops that call bpf_list_head_free for
+ * the same map value again.
+ */
+ __bpf_spin_lock_irqsave(spin_lock);
+ if (!head->next || list_empty(head))
+ goto unlock;
+ head = head->next;
+unlock:
+ INIT_LIST_HEAD(orig_head);
+ __bpf_spin_unlock_irqrestore(spin_lock);
+
+ while (head != orig_head) {
+ void *obj = head;
+
+ obj -= field->list_head.node_offset;
+ head = head->next;
+ /* TODO: Rework later */
+ kfree(obj);
+ }
+}
+
BTF_SET8_START(tracing_btf_ids)
#ifdef CONFIG_KEXEC_CORE
BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 85532d301124..fdbae52f463f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -536,6 +536,9 @@ void btf_record_free(struct btf_record *rec)
module_put(rec->fields[i].kptr.module);
btf_put(rec->fields[i].kptr.btf);
break;
+ case BPF_LIST_HEAD:
+ /* Nothing to release for bpf_list_head */
+ break;
default:
WARN_ON_ONCE(1);
continue;
@@ -578,6 +581,9 @@ struct btf_record *btf_record_dup(const struct btf_record *rec)
goto free;
}
break;
+ case BPF_LIST_HEAD:
+ /* Nothing to acquire for bpf_list_head */
+ break;
default:
ret = -EFAULT;
WARN_ON_ONCE(1);
@@ -637,6 +643,11 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj)
case BPF_KPTR_REF:
field->kptr.dtor((void *)xchg((unsigned long *)field_ptr, 0));
break;
+ case BPF_LIST_HEAD:
+ if (WARN_ON_ONCE(rec->spin_lock_off < 0))
+ continue;
+ bpf_list_head_free(field, field_ptr, obj + rec->spin_lock_off);
+ break;
default:
WARN_ON_ONCE(1);
continue;
@@ -965,7 +976,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
if (!value_type || value_size != map->value_size)
return -EINVAL;
- map->record = btf_parse_fields(btf, value_type, BPF_SPIN_LOCK | BPF_TIMER | BPF_KPTR,
+ map->record = btf_parse_fields(btf, value_type,
+ BPF_SPIN_LOCK | BPF_TIMER | BPF_KPTR | BPF_LIST_HEAD,
map->value_size);
if (!IS_ERR_OR_NULL(map->record)) {
int i;
@@ -1012,6 +1024,14 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
goto free_map_tab;
}
break;
+ case BPF_LIST_HEAD:
+ if (map->map_type != BPF_MAP_TYPE_HASH &&
+ map->map_type != BPF_MAP_TYPE_LRU_HASH &&
+ map->map_type != BPF_MAP_TYPE_ARRAY) {
+ ret = -EOPNOTSUPP;
+ goto free_map_tab;
+ }
+ break;
default:
/* Fail if map_type checks are missing for a field type */
ret = -EOPNOTSUPP;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 07c0259dfc1a..a50018e2d4a0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12814,6 +12814,13 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
{
enum bpf_prog_type prog_type = resolve_prog_type(prog);
+ if (btf_record_has_field(map->record, BPF_LIST_HEAD)) {
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_list_head yet\n");
+ return -EINVAL;
+ }
+ }
+
if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index fb4c911d2a03..6580448e9f77 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6888,6 +6888,16 @@ struct bpf_dynptr {
__u64 :64;
} __attribute__((aligned(8)));
+struct bpf_list_head {
+ __u64 :64;
+ __u64 :64;
+} __attribute__((aligned(8)));
+
+struct bpf_list_node {
+ __u64 :64;
+ __u64 :64;
+} __attribute__((aligned(8)));
+
struct bpf_sysctl {
__u32 write; /* Sysctl is being read (= 0) or written (= 1).
* Allows 1,2,4-byte read, but no write.
generated by cgit (git 2.34.1) at 2024-06-12 09:48:09 +0000