1/*
 2 * Just-In-Time compiler for BPF filters on MIPS
 3 *
 4 * Copyright (c) 2014 Imagination Technologies Ltd.
 5 * Author: Markos Chandras <markos.chandras@imgtec.com>
 6 *
 7 * This program is free software; you can redistribute it and/or modify it
 8 * under the terms of the GNU General Public License as published by the
 9 * Free Software Foundation; version 2 of the License.
10 */
11
12#ifndef BPF_JIT_MIPS_OP_H
13#define BPF_JIT_MIPS_OP_H
14
15/* Registers used by JIT */
16#define MIPS_R_ZERO	0
17#define MIPS_R_V0	2
18#define MIPS_R_A0	4
19#define MIPS_R_A1	5
20#define MIPS_R_T4	12
21#define MIPS_R_T5	13
22#define MIPS_R_T6	14
23#define MIPS_R_T7	15
24#define MIPS_R_S0	16
25#define MIPS_R_S1	17
26#define MIPS_R_S2	18
27#define MIPS_R_S3	19
28#define MIPS_R_S4	20
29#define MIPS_R_S5	21
30#define MIPS_R_S6	22
31#define MIPS_R_S7	23
32#define MIPS_R_SP	29
33#define MIPS_R_RA	31
34
35/* Conditional codes */
36#define MIPS_COND_EQ	0x1
37#define MIPS_COND_GE	(0x1 << 1)
38#define MIPS_COND_GT	(0x1 << 2)
39#define MIPS_COND_NE	(0x1 << 3)
40#define MIPS_COND_ALL	(0x1 << 4)
41/* Conditionals on X register or K immediate */
42#define MIPS_COND_X	(0x1 << 5)
43#define MIPS_COND_K	(0x1 << 6)
44
45#define r_ret	MIPS_R_V0
46
47/*
48 * Use 2 scratch registers to avoid pipeline interlocks.
49 * There is no overhead during epilogue and prologue since
50 * any of the $s0-$s6 registers will only be preserved if
51 * they are going to actually be used.
52 */
53#define r_skb_hl	MIPS_R_S0 /* skb header length */
54#define r_skb_data	MIPS_R_S1 /* skb actual data */
55#define r_off		MIPS_R_S2
56#define r_A		MIPS_R_S3
57#define r_X		MIPS_R_S4
58#define r_skb		MIPS_R_S5
59#define r_M		MIPS_R_S6
60#define r_skb_len	MIPS_R_S7
61#define r_s0		MIPS_R_T4 /* scratch reg 1 */
62#define r_s1		MIPS_R_T5 /* scratch reg 2 */
63#define r_tmp_imm	MIPS_R_T6 /* No need to preserve this */
64#define r_tmp		MIPS_R_T7 /* No need to preserve this */
65#define r_zero		MIPS_R_ZERO
66#define r_sp		MIPS_R_SP
67#define r_ra		MIPS_R_RA
68
69#ifndef __ASSEMBLY__
70
71/* Declare ASM helpers */
72
73#define DECLARE_LOAD_FUNC(func) \
74	extern u8 func(unsigned long *skb, int offset); \
75	extern u8 func##_negative(unsigned long *skb, int offset); \
76	extern u8 func##_positive(unsigned long *skb, int offset)
77
78DECLARE_LOAD_FUNC(sk_load_word);
79DECLARE_LOAD_FUNC(sk_load_half);
80DECLARE_LOAD_FUNC(sk_load_byte);
81
82#endif
83
84#endif /* BPF_JIT_MIPS_OP_H */