Add bpf_rcu_read_lock() and bpf_rcu_read_unlock() helpers.
Both helpers are available to all program types with
CAP_BPF capability.
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
include/linux/bpf.h | 2 ++
include/uapi/linux/bpf.h | 14 ++++++++++++++
kernel/bpf/core.c | 2 ++
kernel/bpf/helpers.c | 26 ++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 14 ++++++++++++++
5 files changed, 58 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 8d948bfcb984..a9bda4c91fc7 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2554,6 +2554,8 @@ extern const struct bpf_func_proto bpf_get_retval_proto;
extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
extern const struct bpf_func_proto bpf_cgrp_storage_get_proto;
extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto;
+extern const struct bpf_func_proto bpf_rcu_read_lock_proto;
+extern const struct bpf_func_proto bpf_rcu_read_unlock_proto;
const struct bpf_func_proto *tracing_prog_func_proto(
enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 94659f6b3395..e86389cd6133 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5481,6 +5481,18 @@ union bpf_attr {
* 0 on success.
*
* **-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * void bpf_rcu_read_lock(void)
+ * Description
+ * Call kernel rcu_read_lock().
+ * Return
+ * None.
+ *
+ * void bpf_rcu_read_unlock(void)
+ * Description
+ * Call kernel rcu_read_unlock().
+ * Return
+ * None.
*/
#define ___BPF_FUNC_MAPPER(FN, ctx...) \
FN(unspec, 0, ##ctx) \
@@ -5695,6 +5707,8 @@ union bpf_attr {
FN(user_ringbuf_drain, 209, ##ctx) \
FN(cgrp_storage_get, 210, ##ctx) \
FN(cgrp_storage_delete, 211, ##ctx) \
+ FN(rcu_read_lock, 212, ##ctx) \
+ FN(rcu_read_unlock, 213, ##ctx) \
/* */
/* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 9c16338bcbe8..26858b579dfc 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2627,6 +2627,8 @@ const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
const struct bpf_func_proto bpf_spin_lock_proto __weak;
const struct bpf_func_proto bpf_spin_unlock_proto __weak;
const struct bpf_func_proto bpf_jiffies64_proto __weak;
+const struct bpf_func_proto bpf_rcu_read_lock_proto __weak;
+const struct bpf_func_proto bpf_rcu_read_unlock_proto __weak;
const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 124fd199ce5c..f19416dc8ad1 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1273,6 +1273,28 @@ static const struct bpf_func_proto bpf_timer_start_proto = {
.arg3_type = ARG_ANYTHING,
};
+BPF_CALL_0(bpf_rcu_read_lock) {
+ rcu_read_lock();
+ return 0;
+}
+
+const struct bpf_func_proto bpf_rcu_read_lock_proto = {
+ .func = bpf_rcu_read_lock,
+ .gpl_only = false,
+ .ret_type = RET_VOID,
+};
+
+BPF_CALL_0(bpf_rcu_read_unlock) {
+ rcu_read_unlock();
+ return 0;
+}
+
+const struct bpf_func_proto bpf_rcu_read_unlock_proto = {
+ .func = bpf_rcu_read_unlock,
+ .gpl_only = false,
+ .ret_type = RET_VOID,
+};
+
static void drop_prog_refcnt(struct bpf_hrtimer *t)
{
struct bpf_prog *prog = t->prog;
@@ -1627,6 +1649,10 @@ bpf_base_func_proto(enum bpf_func_id func_id)
return &bpf_spin_lock_proto;
case BPF_FUNC_spin_unlock:
return &bpf_spin_unlock_proto;
+ case BPF_FUNC_rcu_read_lock:
+ return &bpf_rcu_read_lock_proto;
+ case BPF_FUNC_rcu_read_unlock:
+ return &bpf_rcu_read_unlock_proto;
case BPF_FUNC_jiffies64:
return &bpf_jiffies64_proto;
case BPF_FUNC_per_cpu_ptr:
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 94659f6b3395..e86389cd6133 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5481,6 +5481,18 @@ union bpf_attr {
* 0 on success.
*
* **-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * void bpf_rcu_read_lock(void)
+ * Description
+ * Call kernel rcu_read_lock().
+ * Return
+ * None.
+ *
+ * void bpf_rcu_read_unlock(void)
+ * Description
+ * Call kernel rcu_read_unlock().
+ * Return
+ * None.
*/
#define ___BPF_FUNC_MAPPER(FN, ctx...) \
FN(unspec, 0, ##ctx) \
@@ -5695,6 +5707,8 @@ union bpf_attr {
FN(user_ringbuf_drain, 209, ##ctx) \
FN(cgrp_storage_get, 210, ##ctx) \
FN(cgrp_storage_delete, 211, ##ctx) \
+ FN(rcu_read_lock, 212, ##ctx) \
+ FN(rcu_read_unlock, 213, ##ctx) \
/* */
/* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
--
2.30.2
