4 files changed, 207 insertions, 3 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 95a7abd0ee92..ee5275e7d4df 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -22,6 +22,8 @@ struct perf_event;
 struct bpf_prog;
 struct bpf_map;
 struct sock;
+struct seq_file;
+struct btf;
 
 /* map is generic key/value storage optionally accesible by eBPF programs */
 struct bpf_map_ops {
@@ -43,10 +45,14 @@ struct bpf_map_ops {
         void (*map_fd_put_ptr)(void *ptr);
         u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
         u32 (*map_fd_sys_lookup_elem)(void *ptr);
+        void (*map_seq_show_elem)(struct bpf_map *map, void *key,
+                                  struct seq_file *m);
+        int (*map_check_btf)(const struct bpf_map *map, const struct btf *btf,
+                             u32 key_type_id, u32 value_type_id);
 };
 
 struct bpf_map {
-        /* 1st cacheline with read-mostly members of which some
+        /* The first two cachelines with read-mostly members of which some
          * are also accessed in fast-path (e.g. ops, max_entries).
          */
         const struct bpf_map_ops *ops ____cacheline_aligned;
@@ -62,10 +68,13 @@ struct bpf_map {
         u32 pages;
         u32 id;
         int numa_node;
+        u32 btf_key_id;
+        u32 btf_value_id;
+        struct btf *btf;
         bool unpriv_array;
-        /* 7 bytes hole */
+        /* 55 bytes hole */
 
-        /* 2nd cacheline with misc members to avoid false sharing
+        /* The 3rd and 4th cacheline with misc members to avoid false sharing
          * particularly with refcounting.
          */
         struct user_struct *user ____cacheline_aligned;
@@ -100,6 +109,11 @@ static inline struct bpf_offloaded_map *map_to_offmap(struct bpf_map *map)
         return container_of(map, struct bpf_offloaded_map, map);
 }
 
+static inline bool bpf_map_support_seq_show(const struct bpf_map *map)
+{
+        return map->ops->map_seq_show_elem && map->ops->map_check_btf;
+}
+
 extern const struct bpf_map_ops bpf_map_offload_ops;
 
 /* function argument constraints */
diff --git a/include/linux/btf.h b/include/linux/btf.h
new file mode 100644
index 000000000000..a966dc6d61ee
--- /dev/null
+++ b/include/linux/btf.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Facebook */
+
+#ifndef _LINUX_BTF_H
+#define _LINUX_BTF_H 1
+
+#include <linux/types.h>
+
+struct btf;
+struct btf_type;
+union bpf_attr;
+
+extern const struct file_operations btf_fops;
+
+void btf_put(struct btf *btf);
+int btf_new_fd(const union bpf_attr *attr);
+struct btf *btf_get_by_fd(int fd);
+int btf_get_info_by_fd(const struct btf *btf,
+                       const union bpf_attr *attr,
+                       union bpf_attr __user *uattr);
+/* Figure out the size of a type_id.  If type_id is a modifier
+ * (e.g. const), it will be resolved to find out the type with size.
+ *
+ * For example:
+ * In describing "const void *",  type_id is "const" and "const"
+ * refers to "void *".  The return type will be "void *".
+ *
+ * If type_id is a simple "int", then return type will be "int".
+ *
+ * @btf: struct btf object
+ * @type_id: Find out the size of type_id. The type_id of the return
+ *           type is set to *type_id.
+ * @ret_size: It can be NULL.  If not NULL, the size of the return
+ *            type is set to *ret_size.
+ * Return: The btf_type (resolved to another type with size info if needed).
+ *         NULL is returned if type_id itself does not have size info
+ *         (e.g. void) or it cannot be resolved to another type that
+ *         has size info.
+ *         *type_id and *ret_size will not be changed in the
+ *         NULL return case.
+ */
+const struct btf_type *btf_type_id_size(const struct btf *btf,
+                                        u32 *type_id,
+                                        u32 *ret_size);
+void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
+                       struct seq_file *m);
+
+#endif
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 9a2d1a04eb24..c8383a289f7b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -95,6 +95,7 @@ enum bpf_cmd {
         BPF_OBJ_GET_INFO_BY_FD,
         BPF_PROG_QUERY,
         BPF_RAW_TRACEPOINT_OPEN,
+        BPF_BTF_LOAD,
 };
 
 enum bpf_map_type {
@@ -279,6 +280,9 @@ union bpf_attr {
                                          */
                 char    map_name[BPF_OBJ_NAME_LEN];
                 __u32   map_ifindex;    /* ifindex of netdev to create on */
+                __u32   btf_fd;         /* fd pointing to a BTF type data */
+                __u32   btf_key_id;     /* BTF type_id of the key */
+                __u32   btf_value_id;   /* BTF type_id of the value */
         };
 
         struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -363,6 +367,14 @@ union bpf_attr {
                 __u64 name;
                 __u32 prog_fd;
         } raw_tracepoint;
+
+        struct { /* anonymous struct for BPF_BTF_LOAD */
+                __aligned_u64   btf;
+                __aligned_u64   btf_log_buf;
+                __u32           btf_size;
+                __u32           btf_log_size;
+                __u32           btf_log_level;
+        };
 } __attribute__((aligned(8)));
 
 /* BPF helper function descriptions:
diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h
new file mode 100644
index 000000000000..74a30b1090df
--- /dev/null
+++ b/include/uapi/linux/btf.h
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* Copyright (c) 2018 Facebook */
+#ifndef _UAPI__LINUX_BTF_H__
+#define _UAPI__LINUX_BTF_H__
+
+#include <linux/types.h>
+
+#define BTF_MAGIC       0xeB9F
+#define BTF_MAGIC_SWAP  0x9FeB
+#define BTF_VERSION     1
+#define BTF_FLAGS_COMPR 0x01
+
+struct btf_header {
+        __u16   magic;
+        __u8    version;
+        __u8    flags;
+
+        __u32   parent_label;
+        __u32   parent_name;
+
+        /* All offsets are in bytes relative to the end of this header */
+        __u32   label_off;      /* offset of label section      */
+        __u32   object_off;     /* offset of data object section*/
+        __u32   func_off;       /* offset of function section   */
+        __u32   type_off;       /* offset of type section       */
+        __u32   str_off;        /* offset of string section     */
+        __u32   str_len;        /* length of string section     */
+};
+
+/* Max # of type identifier */
+#define BTF_MAX_TYPE    0x7fffffff
+/* Max offset into the string section */
+#define BTF_MAX_NAME_OFFSET     0x7fffffff
+/* Max # of struct/union/enum members or func args */
+#define BTF_MAX_VLEN    0xffff
+
+/* The type id is referring to a parent BTF */
+#define BTF_TYPE_PARENT(id)     (((id) >> 31) & 0x1)
+#define BTF_TYPE_ID(id)         ((id) & BTF_MAX_TYPE)
+
+/* String is in the ELF string section */
+#define BTF_STR_TBL_ELF_ID(ref) (((ref) >> 31) & 0x1)
+#define BTF_STR_OFFSET(ref)     ((ref) & BTF_MAX_NAME_OFFSET)
+
+struct btf_type {
+        __u32 name;
+        /* "info" bits arrangement
+         * bits  0-15: vlen (e.g. # of struct's members)
+         * bits 16-23: unused
+         * bits 24-28: kind (e.g. int, ptr, array...etc)
+         * bits 29-30: unused
+         * bits    31: root
+         */
+        __u32 info;
+        /* "size" is used by INT, ENUM, STRUCT and UNION.
+         * "size" tells the size of the type it is describing.
+         *
+         * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT.
+         * "type" is a type_id referring to another type.
+         */
+        union {
+                __u32 size;
+                __u32 type;
+        };
+};
+
+#define BTF_INFO_KIND(info)     (((info) >> 24) & 0x1f)
+#define BTF_INFO_ISROOT(info)   (!!(((info) >> 24) & 0x80))
+#define BTF_INFO_VLEN(info)     ((info) & 0xffff)
+
+#define BTF_KIND_UNKN           0       /* Unknown      */
+#define BTF_KIND_INT            1       /* Integer      */
+#define BTF_KIND_PTR            2       /* Pointer      */
+#define BTF_KIND_ARRAY          3       /* Array        */
+#define BTF_KIND_STRUCT         4       /* Struct       */
+#define BTF_KIND_UNION          5       /* Union        */
+#define BTF_KIND_ENUM           6       /* Enumeration  */
+#define BTF_KIND_FWD            7       /* Forward      */
+#define BTF_KIND_TYPEDEF        8       /* Typedef      */
+#define BTF_KIND_VOLATILE       9       /* Volatile     */
+#define BTF_KIND_CONST          10      /* Const        */
+#define BTF_KIND_RESTRICT       11      /* Restrict     */
+#define BTF_KIND_MAX            11
+#define NR_BTF_KINDS            12
+
+/* For some specific BTF_KIND, "struct btf_type" is immediately
+ * followed by extra data.
+ */
+
+/* BTF_KIND_INT is followed by a u32 and the following
+ * is the 32 bits arrangement:
+ */
+#define BTF_INT_ENCODING(VAL)   (((VAL) & 0xff000000) >> 24)
+#define BTF_INT_OFFSET(VAL)     (((VAL  & 0x00ff0000)) >> 16)
+#define BTF_INT_BITS(VAL)       ((VAL)  & 0x0000ffff)
+
+/* Attributes stored in the BTF_INT_ENCODING */
+#define BTF_INT_SIGNED  0x1
+#define BTF_INT_CHAR    0x2
+#define BTF_INT_BOOL    0x4
+#define BTF_INT_VARARGS 0x8
+
+/* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
+ * The exact number of btf_enum is stored in the vlen (of the
+ * info in "struct btf_type").
+ */
+struct btf_enum {
+        __u32   name;
+        __s32   val;
+};
+
+/* BTF_KIND_ARRAY is followed by one "struct btf_array" */
+struct btf_array {
+        __u32   type;
+        __u32   index_type;
+        __u32   nelems;
+};
+
+/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
+ * by multiple "struct btf_member".  The exact number
+ * of btf_member is stored in the vlen (of the info in
+ * "struct btf_type").
+ */
+struct btf_member {
+        __u32   name;
+        __u32   type;
+        __u32   offset; /* offset in bits */
+};
+
+#endif /* _UAPI__LINUX_BTF_H__ */