1 files changed, 223 insertions, 45 deletions

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 596471189176..edef96ceffa3 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -19,6 +19,7 @@
 #include <linux/bpf_verifier.h>
 #include <linux/btf.h>
 #include <linux/btf_ids.h>
+#include <linux/bpf.h>
 #include <linux/bpf_lsm.h>
 #include <linux/skmsg.h>
 #include <linux/perf_event.h>
@@ -241,6 +242,12 @@ struct btf_id_dtor_kfunc_tab {
 	struct btf_id_dtor_kfunc dtors[];
 };
 
+struct btf_struct_ops_tab {
+	u32 cnt;
+	u32 capacity;
+	struct bpf_struct_ops_desc ops[];
+};
+
 struct btf {
 	void *data;
 	struct btf_type **types;
@@ -258,6 +265,7 @@ struct btf {
 	struct btf_kfunc_set_tab *kfunc_set_tab;
 	struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
 	struct btf_struct_metas *struct_meta_tab;
+	struct btf_struct_ops_tab *struct_ops_tab;
 
 	/* split BTF support */
 	struct btf *base_btf;
@@ -1688,11 +1696,20 @@ static void btf_free_struct_meta_tab(struct btf *btf)
 	btf->struct_meta_tab = NULL;
 }
 
+static void btf_free_struct_ops_tab(struct btf *btf)
+{
+	struct btf_struct_ops_tab *tab = btf->struct_ops_tab;
+
+	kfree(tab);
+	btf->struct_ops_tab = NULL;
+}
+
 static void btf_free(struct btf *btf)
 {
 	btf_free_struct_meta_tab(btf);
 	btf_free_dtor_kfunc_tab(btf);
 	btf_free_kfunc_set_tab(btf);
+	btf_free_struct_ops_tab(btf);
 	kvfree(btf->types);
 	kvfree(btf->resolved_sizes);
 	kvfree(btf->resolved_ids);
@@ -1707,6 +1724,11 @@ static void btf_free_rcu(struct rcu_head *rcu)
 	btf_free(btf);
 }
 
+const char *btf_get_name(const struct btf *btf)
+{
+	return btf->name;
+}
+
 void btf_get(struct btf *btf)
 {
 	refcount_inc(&btf->refcnt);
@@ -3310,30 +3332,48 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
 	return BTF_FIELD_FOUND;
 }
 
-const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
-				    int comp_idx, const char *tag_key)
+int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
+			   int comp_idx, const char *tag_key, int last_id)
 {
-	const char *value = NULL;
-	int i;
+	int len = strlen(tag_key);
+	int i, n;
 
-	for (i = 1; i < btf_nr_types(btf); i++) {
+	for (i = last_id + 1, n = btf_nr_types(btf); i < n; 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)
+		if (pt != btf_type_by_id(btf, t->type))
+			continue;
+		if (btf_type_decl_tag(t)->component_idx != comp_idx)
 			continue;
 		if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
 			continue;
-		/* Prevent duplicate entries for same type */
-		if (value)
-			return ERR_PTR(-EEXIST);
-		value = __btf_name_by_offset(btf, t->name_off) + len;
+		return i;
 	}
-	if (!value)
-		return ERR_PTR(-ENOENT);
+	return -ENOENT;
+}
+
+const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
+				    int comp_idx, const char *tag_key)
+{
+	const char *value = NULL;
+	const struct btf_type *t;
+	int len, id;
+
+	id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	t = btf_type_by_id(btf, id);
+	len = strlen(tag_key);
+	value = __btf_name_by_offset(btf, t->name_off) + len;
+
+	/* Prevent duplicate entries for same type */
+	id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id);
+	if (id >= 0)
+		return ERR_PTR(-EEXIST);
+
 	return value;
 }
 
@@ -5933,8 +5973,6 @@ struct btf *btf_parse_vmlinux(void)
 	/* btf_parse_vmlinux() runs under bpf_verifier_lock */
 	bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
 
-	bpf_struct_ops_init(btf, log);
-
 	refcount_set(&btf->refcnt, 1);
 
 	err = btf_alloc_id(btf);
@@ -6284,6 +6322,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		__btf_name_by_offset(btf, t->name_off));
 	return true;
 }
+EXPORT_SYMBOL_GPL(btf_ctx_access);
 
 enum bpf_struct_walk_result {
 	/* < 0 error */
@@ -6946,6 +6985,11 @@ static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
 	return false;
 }
 
+enum btf_arg_tag {
+	ARG_TAG_CTX = 0x1,
+	ARG_TAG_NONNULL = 0x2,
+};
+
 /* Process BTF of a function to produce high-level expectation of function
  * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
  * is cached in subprog info for reuse.
@@ -7027,70 +7071,86 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
 	 * Only PTR_TO_CTX and SCALAR are supported atm.
 	 */
 	for (i = 0; i < nargs; i++) {
-		bool is_nonnull = false;
-		const char *tag;
-
-		t = btf_type_by_id(btf, args[i].type);
+		u32 tags = 0;
+		int id = 0;
 
-		tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:");
-		if (IS_ERR(tag) && PTR_ERR(tag) == -ENOENT) {
-			tag = NULL;
-		} else if (IS_ERR(tag)) {
-			bpf_log(log, "arg#%d type's tag fetching failure: %ld\n", i, PTR_ERR(tag));
-			return PTR_ERR(tag);
-		}
 		/* 'arg:<tag>' decl_tag takes precedence over derivation of
 		 * register type from BTF type itself
 		 */
-		if (tag) {
+		while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) {
+			const struct btf_type *tag_t = btf_type_by_id(btf, id);
+			const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4;
+
 			/* disallow arg tags in static subprogs */
 			if (!is_global) {
 				bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
 				return -EOPNOTSUPP;
 			}
+
 			if (strcmp(tag, "ctx") == 0) {
-				sub->args[i].arg_type = ARG_PTR_TO_CTX;
-				continue;
+				tags |= ARG_TAG_CTX;
+			} else if (strcmp(tag, "nonnull") == 0) {
+				tags |= ARG_TAG_NONNULL;
+			} else {
+				bpf_log(log, "arg#%d has unsupported set of tags\n", i);
+				return -EOPNOTSUPP;
 			}
-			if (strcmp(tag, "nonnull") == 0)
-				is_nonnull = true;
+		}
+		if (id != -ENOENT) {
+			bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id);
+			return id;
 		}
 
+		t = btf_type_by_id(btf, args[i].type);
 		while (btf_type_is_modifier(t))
 			t = btf_type_by_id(btf, t->type);
-		if (btf_type_is_int(t) || btf_is_any_enum(t)) {
-			sub->args[i].arg_type = ARG_ANYTHING;
-			continue;
-		}
-		if (btf_type_is_ptr(t) && btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+		if (!btf_type_is_ptr(t))
+			goto skip_pointer;
+
+		if ((tags & ARG_TAG_CTX) || btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+			if (tags & ~ARG_TAG_CTX) {
+				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
+				return -EINVAL;
+			}
 			sub->args[i].arg_type = ARG_PTR_TO_CTX;
 			continue;
 		}
-		if (btf_type_is_ptr(t) && btf_is_dynptr_ptr(btf, t)) {
+		if (btf_is_dynptr_ptr(btf, t)) {
+			if (tags) {
+				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
+				return -EINVAL;
+			}
 			sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
 			continue;
 		}
-		if (is_global && btf_type_is_ptr(t)) {
+		if (is_global) { /* generic user data pointer */
 			u32 mem_size;
 
 			t = btf_type_skip_modifiers(btf, t->type, NULL);
 			ref_t = btf_resolve_size(btf, t, &mem_size);
 			if (IS_ERR(ref_t)) {
-				bpf_log(log,
-				    "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
-				    i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
+				bpf_log(log, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+					i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
 					PTR_ERR(ref_t));
 				return -EINVAL;
 			}
 
-			sub->args[i].arg_type = is_nonnull ? ARG_PTR_TO_MEM : ARG_PTR_TO_MEM_OR_NULL;
+			sub->args[i].arg_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL;
+			if (tags & ARG_TAG_NONNULL)
+				sub->args[i].arg_type &= ~PTR_MAYBE_NULL;
 			sub->args[i].mem_size = mem_size;
 			continue;
 		}
-		if (is_nonnull) {
-			bpf_log(log, "arg#%d marked as non-null, but is not a pointer type\n", i);
+
+skip_pointer:
+		if (tags) {
+			bpf_log(log, "arg#%d has pointer tag, but is not a pointer type\n", i);
 			return -EINVAL;
 		}
+		if (btf_type_is_int(t) || btf_is_any_enum(t)) {
+			sub->args[i].arg_type = ARG_ANYTHING;
+			continue;
+		}
 		bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
 			i, btf_type_str(t), tname);
 		return -EINVAL;
@@ -8645,3 +8705,121 @@ bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
 
 	return !strncmp(reg_name, arg_name, cmp_len);
 }
+
+#ifdef CONFIG_BPF_JIT
+static int
+btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
+		   struct bpf_verifier_log *log)
+{
+	struct btf_struct_ops_tab *tab, *new_tab;
+	int i, err;
+
+	tab = btf->struct_ops_tab;
+	if (!tab) {
+		tab = kzalloc(offsetof(struct btf_struct_ops_tab, ops[4]),
+			      GFP_KERNEL);
+		if (!tab)
+			return -ENOMEM;
+		tab->capacity = 4;
+		btf->struct_ops_tab = tab;
+	}
+
+	for (i = 0; i < tab->cnt; i++)
+		if (tab->ops[i].st_ops == st_ops)
+			return -EEXIST;
+
+	if (tab->cnt == tab->capacity) {
+		new_tab = krealloc(tab,
+				   offsetof(struct btf_struct_ops_tab,
+					    ops[tab->capacity * 2]),
+				   GFP_KERNEL);
+		if (!new_tab)
+			return -ENOMEM;
+		tab = new_tab;
+		tab->capacity *= 2;
+		btf->struct_ops_tab = tab;
+	}
+
+	tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
+
+	err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
+	if (err)
+		return err;
+
+	btf->struct_ops_tab->cnt++;
+
+	return 0;
+}
+
+const struct bpf_struct_ops_desc *
+bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
+{
+	const struct bpf_struct_ops_desc *st_ops_list;
+	unsigned int i;
+	u32 cnt;
+
+	if (!value_id)
+		return NULL;
+	if (!btf->struct_ops_tab)
+		return NULL;
+
+	cnt = btf->struct_ops_tab->cnt;
+	st_ops_list = btf->struct_ops_tab->ops;
+	for (i = 0; i < cnt; i++) {
+		if (st_ops_list[i].value_id == value_id)
+			return &st_ops_list[i];
+	}
+
+	return NULL;
+}
+
+const struct bpf_struct_ops_desc *
+bpf_struct_ops_find(struct btf *btf, u32 type_id)
+{
+	const struct bpf_struct_ops_desc *st_ops_list;
+	unsigned int i;
+	u32 cnt;
+
+	if (!type_id)
+		return NULL;
+	if (!btf->struct_ops_tab)
+		return NULL;
+
+	cnt = btf->struct_ops_tab->cnt;
+	st_ops_list = btf->struct_ops_tab->ops;
+	for (i = 0; i < cnt; i++) {
+		if (st_ops_list[i].type_id == type_id)
+			return &st_ops_list[i];
+	}
+
+	return NULL;
+}
+
+int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
+{
+	struct bpf_verifier_log *log;
+	struct btf *btf;
+	int err = 0;
+
+	btf = btf_get_module_btf(st_ops->owner);
+	if (!btf)
+		return -EINVAL;
+
+	log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
+	if (!log) {
+		err = -ENOMEM;
+		goto errout;
+	}
+
+	log->level = BPF_LOG_KERNEL;
+
+	err = btf_add_struct_ops(btf, st_ops, log);
+
+errout:
+	kfree(log);
+	btf_put(btf);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(__register_bpf_struct_ops);
+#endif