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-rw-r--r--include/linux/btf.h473
1 files changed, 465 insertions, 8 deletions
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 2bf641829664..b2983706292f 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -5,21 +5,147 @@
#define _LINUX_BTF_H 1
#include <linux/types.h>
+#include <linux/bpfptr.h>
+#include <linux/bsearch.h>
+#include <linux/btf_ids.h>
#include <uapi/linux/btf.h>
#include <uapi/linux/bpf.h>
#define BTF_TYPE_EMIT(type) ((void)(type *)0)
+#define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
+
+/* These need to be macros, as the expressions are used in assembler input */
+#define KF_ACQUIRE (1 << 0) /* kfunc is an acquire function */
+#define KF_RELEASE (1 << 1) /* kfunc is a release function */
+#define KF_RET_NULL (1 << 2) /* kfunc returns a pointer that may be NULL */
+/* Trusted arguments are those which are guaranteed to be valid when passed to
+ * the kfunc. It is used to enforce that pointers obtained from either acquire
+ * kfuncs, or from the main kernel on a tracepoint or struct_ops callback
+ * invocation, remain unmodified when being passed to helpers taking trusted
+ * args.
+ *
+ * Consider, for example, the following new task tracepoint:
+ *
+ * SEC("tp_btf/task_newtask")
+ * int BPF_PROG(new_task_tp, struct task_struct *task, u64 clone_flags)
+ * {
+ * ...
+ * }
+ *
+ * And the following kfunc:
+ *
+ * BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
+ *
+ * All invocations to the kfunc must pass the unmodified, unwalked task:
+ *
+ * bpf_task_acquire(task); // Allowed
+ * bpf_task_acquire(task->last_wakee); // Rejected, walked task
+ *
+ * Programs may also pass referenced tasks directly to the kfunc:
+ *
+ * struct task_struct *acquired;
+ *
+ * acquired = bpf_task_acquire(task); // Allowed, same as above
+ * bpf_task_acquire(acquired); // Allowed
+ * bpf_task_acquire(task); // Allowed
+ * bpf_task_acquire(acquired->last_wakee); // Rejected, walked task
+ *
+ * Programs may _not_, however, pass a task from an arbitrary fentry/fexit, or
+ * kprobe/kretprobe to the kfunc, as BPF cannot guarantee that all of these
+ * pointers are guaranteed to be safe. For example, the following BPF program
+ * would be rejected:
+ *
+ * SEC("kretprobe/free_task")
+ * int BPF_PROG(free_task_probe, struct task_struct *tsk)
+ * {
+ * struct task_struct *acquired;
+ *
+ * acquired = bpf_task_acquire(acquired); // Rejected, not a trusted pointer
+ * bpf_task_release(acquired);
+ *
+ * return 0;
+ * }
+ */
+#define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer arguments */
+#define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */
+#define KF_DESTRUCTIVE (1 << 6) /* kfunc performs destructive actions */
+#define KF_RCU (1 << 7) /* kfunc takes either rcu or trusted pointer arguments */
+/* only one of KF_ITER_{NEW,NEXT,DESTROY} could be specified per kfunc */
+#define KF_ITER_NEW (1 << 8) /* kfunc implements BPF iter constructor */
+#define KF_ITER_NEXT (1 << 9) /* kfunc implements BPF iter next method */
+#define KF_ITER_DESTROY (1 << 10) /* kfunc implements BPF iter destructor */
+#define KF_RCU_PROTECTED (1 << 11) /* kfunc should be protected by rcu cs when they are invoked */
+#define KF_FASTCALL (1 << 12) /* kfunc supports bpf_fastcall protocol */
+#define KF_ARENA_RET (1 << 13) /* kfunc returns an arena pointer */
+#define KF_ARENA_ARG1 (1 << 14) /* kfunc takes an arena pointer as its first argument */
+#define KF_ARENA_ARG2 (1 << 15) /* kfunc takes an arena pointer as its second argument */
+
+/*
+ * Tag marking a kernel function as a kfunc. This is meant to minimize the
+ * amount of copy-paste that kfunc authors have to include for correctness so
+ * as to avoid issues such as the compiler inlining or eliding either a static
+ * kfunc, or a global kfunc in an LTO build.
+ */
+#define __bpf_kfunc __used __retain noinline
+
+#define __bpf_kfunc_start_defs() \
+ __diag_push(); \
+ __diag_ignore_all("-Wmissing-declarations", \
+ "Global kfuncs as their definitions will be in BTF");\
+ __diag_ignore_all("-Wmissing-prototypes", \
+ "Global kfuncs as their definitions will be in BTF")
+
+#define __bpf_kfunc_end_defs() __diag_pop()
+#define __bpf_hook_start() __bpf_kfunc_start_defs()
+#define __bpf_hook_end() __bpf_kfunc_end_defs()
+
+/*
+ * Return the name of the passed struct, if exists, or halt the build if for
+ * example the structure gets renamed. In this way, developers have to revisit
+ * the code using that structure name, and update it accordingly.
+ */
+#define stringify_struct(x) \
+ ({ BUILD_BUG_ON(sizeof(struct x) < 0); \
+ __stringify(x); })
struct btf;
struct btf_member;
struct btf_type;
union bpf_attr;
struct btf_show;
+struct btf_id_set;
+struct bpf_prog;
+
+typedef int (*btf_kfunc_filter_t)(const struct bpf_prog *prog, u32 kfunc_id);
+
+struct btf_kfunc_id_set {
+ struct module *owner;
+ struct btf_id_set8 *set;
+ btf_kfunc_filter_t filter;
+};
+
+struct btf_id_dtor_kfunc {
+ u32 btf_id;
+ u32 kfunc_btf_id;
+};
+
+struct btf_struct_meta {
+ u32 btf_id;
+ struct btf_record *record;
+};
+
+struct btf_struct_metas {
+ u32 cnt;
+ struct btf_struct_meta types[];
+};
extern const struct file_operations btf_fops;
+const char *btf_get_name(const struct btf *btf);
+void btf_get(struct btf *btf);
void btf_put(struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr);
+const struct btf_header *btf_header(const struct btf *btf);
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_sz);
struct btf *btf_get_by_fd(int fd);
int btf_get_info_by_fd(const struct btf *btf,
const union bpf_attr *attr,
@@ -88,13 +214,22 @@ int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
char *buf, int len, u64 flags);
int btf_get_fd_by_id(u32 id);
-u32 btf_id(const struct btf *btf);
+u32 btf_obj_id(const struct btf *btf);
+bool btf_is_kernel(const struct btf *btf);
+bool btf_is_module(const struct btf *btf);
+bool btf_is_vmlinux(const struct btf *btf);
+struct module *btf_try_get_module(const struct btf *btf);
+u32 btf_nr_types(const struct btf *btf);
+struct btf *btf_base_btf(const struct btf *btf);
bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
const struct btf_member *m,
u32 expected_offset, u32 expected_size);
-int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
+struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
+ u32 field_mask, u32 value_size);
+int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec);
bool btf_type_is_void(const struct btf_type *t);
s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
+s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p);
const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
u32 id, u32 *res_id);
const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
@@ -104,6 +239,7 @@ const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
const struct btf_type *
btf_resolve_size(const struct btf *btf, const struct btf_type *type,
u32 *type_size);
+const char *btf_type_str(const struct btf_type *t);
#define for_each_member(i, struct_type, member) \
for (i = 0, member = btf_type_member(struct_type); \
@@ -130,16 +266,111 @@ static inline bool btf_type_is_small_int(const struct btf_type *t)
return btf_type_is_int(t) && t->size <= sizeof(u64);
}
+static inline u8 btf_int_encoding(const struct btf_type *t)
+{
+ return BTF_INT_ENCODING(*(u32 *)(t + 1));
+}
+
+static inline bool btf_type_is_signed_int(const struct btf_type *t)
+{
+ return btf_type_is_int(t) && (btf_int_encoding(t) & BTF_INT_SIGNED);
+}
+
static inline bool btf_type_is_enum(const struct btf_type *t)
{
return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
}
+static inline bool btf_is_any_enum(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM ||
+ BTF_INFO_KIND(t->info) == BTF_KIND_ENUM64;
+}
+
+static inline bool btf_kind_core_compat(const struct btf_type *t1,
+ const struct btf_type *t2)
+{
+ return BTF_INFO_KIND(t1->info) == BTF_INFO_KIND(t2->info) ||
+ (btf_is_any_enum(t1) && btf_is_any_enum(t2));
+}
+
+static inline bool str_is_empty(const char *s)
+{
+ return !s || !s[0];
+}
+
+static inline u16 btf_kind(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info);
+}
+
+static inline bool btf_is_enum(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_ENUM;
+}
+
+static inline bool btf_is_enum64(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_ENUM64;
+}
+
+static inline u64 btf_enum64_value(const struct btf_enum64 *e)
+{
+ return ((u64)e->val_hi32 << 32) | e->val_lo32;
+}
+
+static inline bool btf_is_composite(const struct btf_type *t)
+{
+ u16 kind = btf_kind(t);
+
+ return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
+}
+
+static inline bool btf_is_array(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_ARRAY;
+}
+
+static inline bool btf_is_int(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_INT;
+}
+
+static inline bool btf_is_ptr(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_PTR;
+}
+
+static inline u8 btf_int_offset(const struct btf_type *t)
+{
+ return BTF_INT_OFFSET(*(u32 *)(t + 1));
+}
+
+static inline __u8 btf_int_bits(const struct btf_type *t)
+{
+ return BTF_INT_BITS(*(__u32 *)(t + 1));
+}
+
+static inline bool btf_type_is_scalar(const struct btf_type *t)
+{
+ return btf_type_is_int(t) || btf_type_is_enum(t);
+}
+
+static inline bool btf_type_is_fwd(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
+}
+
static inline bool btf_type_is_typedef(const struct btf_type *t)
{
return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF;
}
+static inline bool btf_type_is_volatile(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_VOLATILE;
+}
+
static inline bool btf_type_is_func(const struct btf_type *t)
{
return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
@@ -155,6 +386,11 @@ static inline bool btf_type_is_var(const struct btf_type *t)
return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
}
+static inline bool btf_type_is_type_tag(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG;
+}
+
/* union is only a special case of struct:
* all its offsetof(member) == 0
*/
@@ -165,11 +401,26 @@ static inline bool btf_type_is_struct(const struct btf_type *t)
return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
}
+static inline bool __btf_type_is_struct(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
+}
+
+static inline bool btf_type_is_array(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
+}
+
static inline u16 btf_type_vlen(const struct btf_type *t)
{
return BTF_INFO_VLEN(t->info);
}
+static inline u16 btf_vlen(const struct btf_type *t)
+{
+ return btf_type_vlen(t);
+}
+
static inline u16 btf_func_linkage(const struct btf_type *t)
{
return BTF_INFO_VLEN(t->info);
@@ -180,47 +431,253 @@ static inline bool btf_type_kflag(const struct btf_type *t)
return BTF_INFO_KFLAG(t->info);
}
-static inline u32 btf_member_bit_offset(const struct btf_type *struct_type,
- const struct btf_member *member)
+static inline u32 __btf_member_bit_offset(const struct btf_type *struct_type,
+ const struct btf_member *member)
{
return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
: member->offset;
}
-static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type,
- const struct btf_member *member)
+static inline u32 __btf_member_bitfield_size(const struct btf_type *struct_type,
+ const struct btf_member *member)
{
return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
: 0;
}
+static inline struct btf_member *btf_members(const struct btf_type *t)
+{
+ return (struct btf_member *)(t + 1);
+}
+
+static inline u32 btf_member_bit_offset(const struct btf_type *t, u32 member_idx)
+{
+ const struct btf_member *m = btf_members(t) + member_idx;
+
+ return __btf_member_bit_offset(t, m);
+}
+
+static inline u32 btf_member_bitfield_size(const struct btf_type *t, u32 member_idx)
+{
+ const struct btf_member *m = btf_members(t) + member_idx;
+
+ return __btf_member_bitfield_size(t, m);
+}
+
static inline const struct btf_member *btf_type_member(const struct btf_type *t)
{
return (const struct btf_member *)(t + 1);
}
+static inline struct btf_array *btf_array(const struct btf_type *t)
+{
+ return (struct btf_array *)(t + 1);
+}
+
+static inline struct btf_enum *btf_enum(const struct btf_type *t)
+{
+ return (struct btf_enum *)(t + 1);
+}
+
+static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
+{
+ return (struct btf_enum64 *)(t + 1);
+}
+
static inline const struct btf_var_secinfo *btf_type_var_secinfo(
const struct btf_type *t)
{
return (const struct btf_var_secinfo *)(t + 1);
}
+static inline struct btf_param *btf_params(const struct btf_type *t)
+{
+ return (struct btf_param *)(t + 1);
+}
+
+static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
+{
+ return (struct btf_decl_tag *)(t + 1);
+}
+
+static inline int btf_id_cmp_func(const void *a, const void *b)
+{
+ const int *pa = a, *pb = b;
+
+ return *pa - *pb;
+}
+
+static inline bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
+{
+ return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
+}
+
+static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
+{
+ return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
+}
+
+bool btf_param_match_suffix(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *suffix);
+int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto,
+ u32 arg_no);
+u32 btf_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto, int off);
+
+struct bpf_verifier_log;
+
+#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
+struct bpf_struct_ops;
+int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops);
+const struct bpf_struct_ops_desc *bpf_struct_ops_find_value(struct btf *btf, u32 value_id);
+const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id);
+#else
+static inline const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id)
+{
+ return NULL;
+}
+#endif
+
+enum btf_field_iter_kind {
+ BTF_FIELD_ITER_IDS,
+ BTF_FIELD_ITER_STRS,
+};
+
+struct btf_field_desc {
+ /* once-per-type offsets */
+ int t_off_cnt, t_offs[2];
+ /* member struct size, or zero, if no members */
+ int m_sz;
+ /* repeated per-member offsets */
+ int m_off_cnt, m_offs[1];
+};
+
+struct btf_field_iter {
+ struct btf_field_desc desc;
+ void *p;
+ int m_idx;
+ int off_idx;
+ int vlen;
+};
+
#ifdef CONFIG_BPF_SYSCALL
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
+void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
+int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **map_ids);
+int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t,
+ enum btf_field_iter_kind iter_kind);
+__u32 *btf_field_iter_next(struct btf_field_iter *it);
+
const char *btf_name_by_offset(const struct btf *btf, u32 offset);
+const char *btf_str_by_offset(const struct btf *btf, u32 offset);
struct btf *btf_parse_vmlinux(void);
struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
+u32 *btf_kfunc_id_set_contains(const struct btf *btf, u32 kfunc_btf_id,
+ const struct bpf_prog *prog);
+u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
+ const struct bpf_prog *prog);
+int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
+ const struct btf_kfunc_id_set *s);
+int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset);
+s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id);
+int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
+ struct module *owner);
+struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id);
+bool btf_is_projection_of(const char *pname, const char *tname);
+bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg);
+int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type);
+bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2);
+int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx);
+
+static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
+{
+ if (!btf_type_is_ptr(t))
+ return false;
+
+ t = btf_type_skip_modifiers(btf, t->type, NULL);
+
+ return btf_type_is_struct(t);
+}
#else
static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
u32 type_id)
{
return NULL;
}
+
+static inline void btf_set_base_btf(struct btf *btf, const struct btf *base_btf)
+{
+}
+
+static inline int btf_relocate(void *log, struct btf *btf, const struct btf *base_btf,
+ __u32 **map_ids)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t,
+ enum btf_field_iter_kind iter_kind)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline __u32 *btf_field_iter_next(struct btf_field_iter *it)
+{
+ return NULL;
+}
+
static inline const char *btf_name_by_offset(const struct btf *btf,
u32 offset)
{
return NULL;
}
-#endif
+static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf,
+ u32 kfunc_btf_id,
+ struct bpf_prog *prog)
+{
+ return NULL;
+}
+static inline int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
+ const struct btf_kfunc_id_set *s)
+{
+ return 0;
+}
+static inline s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
+{
+ return -ENOENT;
+}
+static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors,
+ u32 add_cnt, struct module *owner)
+{
+ return 0;
+}
+static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
+{
+ return NULL;
+}
+static inline bool
+btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg)
+{
+ return false;
+}
+static inline int get_kern_ctx_btf_id(struct bpf_verifier_log *log,
+ enum bpf_prog_type prog_type) {
+ return -EINVAL;
+}
+static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2)
+{
+ return false;
+}
+static inline int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx)
+{
+ return -EOPNOTSUPP;
+}
+#endif
#endif