linux_dsm_epyc7002/include/uapi/linux/bpf.h
Alexei Starovoitov 28fbcfa08d bpf: add array type of eBPF maps
add new map type BPF_MAP_TYPE_ARRAY and its implementation

- optimized for fastest possible lookup()
  . in the future verifier/JIT may recognize lookup() with constant key
    and optimize it into constant pointer. Can optimize non-constant
    key into direct pointer arithmetic as well, since pointers and
    value_size are constant for the life of the eBPF program.
    In other words array_map_lookup_elem() may be 'inlined' by verifier/JIT
    while preserving concurrent access to this map from user space

- two main use cases for array type:
  . 'global' eBPF variables: array of 1 element with key=0 and value is a
    collection of 'global' variables which programs can use to keep the state
    between events
  . aggregation of tracing events into fixed set of buckets

- all array elements pre-allocated and zero initialized at init time

- key as an index in array and can only be 4 byte

- map_delete_elem() returns EINVAL, since elements cannot be deleted

- map_update_elem() replaces elements in an non-atomic way
  (for atomic updates hashtable type should be used instead)

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-18 13:43:59 -05:00

165 lines
4.5 KiB
C

/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#ifndef _UAPI__LINUX_BPF_H__
#define _UAPI__LINUX_BPF_H__
#include <linux/types.h>
#include <linux/bpf_common.h>
/* Extended instruction set based on top of classic BPF */
/* instruction classes */
#define BPF_ALU64 0x07 /* alu mode in double word width */
/* ld/ldx fields */
#define BPF_DW 0x18 /* double word */
#define BPF_XADD 0xc0 /* exclusive add */
/* alu/jmp fields */
#define BPF_MOV 0xb0 /* mov reg to reg */
#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
/* change endianness of a register */
#define BPF_END 0xd0 /* flags for endianness conversion: */
#define BPF_TO_LE 0x00 /* convert to little-endian */
#define BPF_TO_BE 0x08 /* convert to big-endian */
#define BPF_FROM_LE BPF_TO_LE
#define BPF_FROM_BE BPF_TO_BE
#define BPF_JNE 0x50 /* jump != */
#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
#define BPF_CALL 0x80 /* function call */
#define BPF_EXIT 0x90 /* function return */
/* Register numbers */
enum {
BPF_REG_0 = 0,
BPF_REG_1,
BPF_REG_2,
BPF_REG_3,
BPF_REG_4,
BPF_REG_5,
BPF_REG_6,
BPF_REG_7,
BPF_REG_8,
BPF_REG_9,
BPF_REG_10,
__MAX_BPF_REG,
};
/* BPF has 10 general purpose 64-bit registers and stack frame. */
#define MAX_BPF_REG __MAX_BPF_REG
struct bpf_insn {
__u8 code; /* opcode */
__u8 dst_reg:4; /* dest register */
__u8 src_reg:4; /* source register */
__s16 off; /* signed offset */
__s32 imm; /* signed immediate constant */
};
/* BPF syscall commands */
enum bpf_cmd {
/* create a map with given type and attributes
* fd = bpf(BPF_MAP_CREATE, union bpf_attr *, u32 size)
* returns fd or negative error
* map is deleted when fd is closed
*/
BPF_MAP_CREATE,
/* lookup key in a given map
* err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
* Using attr->map_fd, attr->key, attr->value
* returns zero and stores found elem into value
* or negative error
*/
BPF_MAP_LOOKUP_ELEM,
/* create or update key/value pair in a given map
* err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
* Using attr->map_fd, attr->key, attr->value, attr->flags
* returns zero or negative error
*/
BPF_MAP_UPDATE_ELEM,
/* find and delete elem by key in a given map
* err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
* Using attr->map_fd, attr->key
* returns zero or negative error
*/
BPF_MAP_DELETE_ELEM,
/* lookup key in a given map and return next key
* err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
* Using attr->map_fd, attr->key, attr->next_key
* returns zero and stores next key or negative error
*/
BPF_MAP_GET_NEXT_KEY,
/* verify and load eBPF program
* prog_fd = bpf(BPF_PROG_LOAD, union bpf_attr *attr, u32 size)
* Using attr->prog_type, attr->insns, attr->license
* returns fd or negative error
*/
BPF_PROG_LOAD,
};
enum bpf_map_type {
BPF_MAP_TYPE_UNSPEC,
BPF_MAP_TYPE_HASH,
BPF_MAP_TYPE_ARRAY,
};
enum bpf_prog_type {
BPF_PROG_TYPE_UNSPEC,
};
/* flags for BPF_MAP_UPDATE_ELEM command */
#define BPF_ANY 0 /* create new element or update existing */
#define BPF_NOEXIST 1 /* create new element if it didn't exist */
#define BPF_EXIST 2 /* update existing element */
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */
__u32 key_size; /* size of key in bytes */
__u32 value_size; /* size of value in bytes */
__u32 max_entries; /* max number of entries in a map */
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
__u32 map_fd;
__aligned_u64 key;
union {
__aligned_u64 value;
__aligned_u64 next_key;
};
__u64 flags;
};
struct { /* anonymous struct used by BPF_PROG_LOAD command */
__u32 prog_type; /* one of enum bpf_prog_type */
__u32 insn_cnt;
__aligned_u64 insns;
__aligned_u64 license;
__u32 log_level; /* verbosity level of verifier */
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied buffer */
};
} __attribute__((aligned(8)));
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
*/
enum bpf_func_id {
BPF_FUNC_unspec,
__BPF_FUNC_MAX_ID,
};
#endif /* _UAPI__LINUX_BPF_H__ */