bpf: Introduce cgroup_{common,current}_func_proto

Split cgroup_base_func_proto into the following:

* cgroup_common_func_proto - common helpers for all cgroup hooks
* cgroup_current_func_proto - common helpers for all cgroup hooks
  running in the process context (== have meaningful 'current').

Move bpf_{g,s}et_retval and other cgroup-related helpers into
kernel/bpf/cgroup.c so they closer to where they are being used.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220823222555.523590-2-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 2bd1b5f..57e9e10 100644 (file)
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -414,6 +414,11 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr,
 int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
 int cgroup_bpf_prog_query(const union bpf_attr *attr,
                          union bpf_attr __user *uattr);
+
+const struct bpf_func_proto *
+cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog);
+const struct bpf_func_proto *
+cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog);
 #else
 
 static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }
@@ -444,6 +449,18 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr,
        return -EINVAL;
 }
 
+static inline const struct bpf_func_proto *
+cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+       return NULL;
+}
+
+static inline const struct bpf_func_proto *
+cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+       return NULL;
+}
+
 static inline int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux,
                                            struct bpf_map *map) { return 0; }
 static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 59b7eb6..189380e 100644 (file)
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1527,6 +1527,37 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
        return ret;
 }
 
+BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
+{
+       /* flags argument is not used now,
+        * but provides an ability to extend the API.
+        * verifier checks that its value is correct.
+        */
+       enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
+       struct bpf_cgroup_storage *storage;
+       struct bpf_cg_run_ctx *ctx;
+       void *ptr;
+
+       /* get current cgroup storage from BPF run context */
+       ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+       storage = ctx->prog_item->cgroup_storage[stype];
+
+       if (stype == BPF_CGROUP_STORAGE_SHARED)
+               ptr = &READ_ONCE(storage->buf)->data[0];
+       else
+               ptr = this_cpu_ptr(storage->percpu_buf);
+
+       return (unsigned long)ptr;
+}
+
+const struct bpf_func_proto bpf_get_local_storage_proto = {
+       .func           = bpf_get_local_storage,
+       .gpl_only       = false,
+       .ret_type       = RET_PTR_TO_MAP_VALUE,
+       .arg1_type      = ARG_CONST_MAP_PTR,
+       .arg2_type      = ARG_ANYTHING,
+};
+
 BPF_CALL_0(bpf_get_retval)
 {
        struct bpf_cg_run_ctx *ctx =
@@ -1558,32 +1589,26 @@ const struct bpf_func_proto bpf_set_retval_proto = {
 };
 
 static const struct bpf_func_proto *
-cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
+       const struct bpf_func_proto *func_proto;
+
+       func_proto = cgroup_common_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
+       func_proto = cgroup_current_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
        switch (func_id) {
-       case BPF_FUNC_get_current_uid_gid:
-               return &bpf_get_current_uid_gid_proto;
-       case BPF_FUNC_get_local_storage:
-               return &bpf_get_local_storage_proto;
-       case BPF_FUNC_get_current_cgroup_id:
-               return &bpf_get_current_cgroup_id_proto;
        case BPF_FUNC_perf_event_output:
                return &bpf_event_output_data_proto;
-       case BPF_FUNC_get_retval:
-               return &bpf_get_retval_proto;
-       case BPF_FUNC_set_retval:
-               return &bpf_set_retval_proto;
        default:
                return bpf_base_func_proto(func_id);
        }
 }
 
-static const struct bpf_func_proto *
-cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
-{
-       return cgroup_base_func_proto(func_id, prog);
-}
-
 static bool cgroup_dev_is_valid_access(int off, int size,
                                       enum bpf_access_type type,
                                       const struct bpf_prog *prog,
@@ -2096,6 +2121,16 @@ static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = {
 static const struct bpf_func_proto *
 sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
+       const struct bpf_func_proto *func_proto;
+
+       func_proto = cgroup_common_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
+       func_proto = cgroup_current_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
        switch (func_id) {
        case BPF_FUNC_strtol:
                return &bpf_strtol_proto;
@@ -2111,8 +2146,10 @@ sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
                return &bpf_sysctl_set_new_value_proto;
        case BPF_FUNC_ktime_get_coarse_ns:
                return &bpf_ktime_get_coarse_ns_proto;
+       case BPF_FUNC_perf_event_output:
+               return &bpf_event_output_data_proto;
        default:
-               return cgroup_base_func_proto(func_id, prog);
+               return bpf_base_func_proto(func_id);
        }
 }
 
@@ -2233,6 +2270,16 @@ static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = {
 static const struct bpf_func_proto *
 cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
+       const struct bpf_func_proto *func_proto;
+
+       func_proto = cgroup_common_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
+       func_proto = cgroup_current_func_proto(func_id, prog);
+       if (func_proto)
+               return func_proto;
+
        switch (func_id) {
 #ifdef CONFIG_NET
        case BPF_FUNC_get_netns_cookie:
@@ -2254,8 +2301,10 @@ cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
        case BPF_FUNC_tcp_sock:
                return &bpf_tcp_sock_proto;
 #endif
+       case BPF_FUNC_perf_event_output:
+               return &bpf_event_output_data_proto;
        default:
-               return cgroup_base_func_proto(func_id, prog);
+               return bpf_base_func_proto(func_id);
        }
 }
 
@@ -2420,3 +2469,33 @@ const struct bpf_verifier_ops cg_sockopt_verifier_ops = {
 
 const struct bpf_prog_ops cg_sockopt_prog_ops = {
 };
+
+/* Common helpers for cgroup hooks. */
+const struct bpf_func_proto *
+cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+       switch (func_id) {
+       case BPF_FUNC_get_local_storage:
+               return &bpf_get_local_storage_proto;
+       case BPF_FUNC_get_retval:
+               return &bpf_get_retval_proto;
+       case BPF_FUNC_set_retval:
+               return &bpf_set_retval_proto;
+       default:
+               return NULL;
+       }
+}
+
+/* Common helpers for cgroup hooks with valid process context. */
+const struct bpf_func_proto *
+cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+       switch (func_id) {
+       case BPF_FUNC_get_current_uid_gid:
+               return &bpf_get_current_uid_gid_proto;
+       case BPF_FUNC_get_current_cgroup_id:
+               return &bpf_get_current_cgroup_id_proto;
+       default:
+               return NULL;
+       }
+}

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 3c1b9bb..6439a87 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -428,40 +428,6 @@ const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
        .arg1_type      = ARG_ANYTHING,
 };
 
-#ifdef CONFIG_CGROUP_BPF
-
-BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
-{
-       /* flags argument is not used now,
-        * but provides an ability to extend the API.
-        * verifier checks that its value is correct.
-        */
-       enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
-       struct bpf_cgroup_storage *storage;
-       struct bpf_cg_run_ctx *ctx;
-       void *ptr;
-
-       /* get current cgroup storage from BPF run context */
-       ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
-       storage = ctx->prog_item->cgroup_storage[stype];
-
-       if (stype == BPF_CGROUP_STORAGE_SHARED)
-               ptr = &READ_ONCE(storage->buf)->data[0];
-       else
-               ptr = this_cpu_ptr(storage->percpu_buf);
-
-       return (unsigned long)ptr;
-}
-
-const struct bpf_func_proto bpf_get_local_storage_proto = {
-       .func           = bpf_get_local_storage,
-       .gpl_only       = false,
-       .ret_type       = RET_PTR_TO_MAP_VALUE,
-       .arg1_type      = ARG_CONST_MAP_PTR,
-       .arg2_type      = ARG_ANYTHING,
-};
-#endif
-
 #define BPF_STRTOX_BASE_MASK 0x1F
 
 static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,