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1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Just-In-Time compiler for BPF filters on MIPS
4  *
5  * Copyright (c) 2014 Imagination Technologies Ltd.
6  * Author: Markos Chandras <markos.chandras@imgtec.com>
7  */
8 
9 #ifndef BPF_JIT_MIPS_OP_H
10 #define BPF_JIT_MIPS_OP_H
11 
12 /* Registers used by JIT */
13 #define MIPS_R_ZERO	0
14 #define MIPS_R_V0	2
15 #define MIPS_R_A0	4
16 #define MIPS_R_A1	5
17 #define MIPS_R_T4	12
18 #define MIPS_R_T5	13
19 #define MIPS_R_T6	14
20 #define MIPS_R_T7	15
21 #define MIPS_R_S0	16
22 #define MIPS_R_S1	17
23 #define MIPS_R_S2	18
24 #define MIPS_R_S3	19
25 #define MIPS_R_S4	20
26 #define MIPS_R_S5	21
27 #define MIPS_R_S6	22
28 #define MIPS_R_S7	23
29 #define MIPS_R_SP	29
30 #define MIPS_R_RA	31
31 
32 /* Conditional codes */
33 #define MIPS_COND_EQ	0x1
34 #define MIPS_COND_GE	(0x1 << 1)
35 #define MIPS_COND_GT	(0x1 << 2)
36 #define MIPS_COND_NE	(0x1 << 3)
37 #define MIPS_COND_ALL	(0x1 << 4)
38 /* Conditionals on X register or K immediate */
39 #define MIPS_COND_X	(0x1 << 5)
40 #define MIPS_COND_K	(0x1 << 6)
41 
42 #define r_ret	MIPS_R_V0
43 
44 /*
45  * Use 2 scratch registers to avoid pipeline interlocks.
46  * There is no overhead during epilogue and prologue since
47  * any of the $s0-$s6 registers will only be preserved if
48  * they are going to actually be used.
49  */
50 #define r_skb_hl	MIPS_R_S0 /* skb header length */
51 #define r_skb_data	MIPS_R_S1 /* skb actual data */
52 #define r_off		MIPS_R_S2
53 #define r_A		MIPS_R_S3
54 #define r_X		MIPS_R_S4
55 #define r_skb		MIPS_R_S5
56 #define r_M		MIPS_R_S6
57 #define r_skb_len	MIPS_R_S7
58 #define r_s0		MIPS_R_T4 /* scratch reg 1 */
59 #define r_s1		MIPS_R_T5 /* scratch reg 2 */
60 #define r_tmp_imm	MIPS_R_T6 /* No need to preserve this */
61 #define r_tmp		MIPS_R_T7 /* No need to preserve this */
62 #define r_zero		MIPS_R_ZERO
63 #define r_sp		MIPS_R_SP
64 #define r_ra		MIPS_R_RA
65 
66 #ifndef __ASSEMBLY__
67 
68 /* Declare ASM helpers */
69 
70 #define DECLARE_LOAD_FUNC(func) \
71 	extern u8 func(unsigned long *skb, int offset); \
72 	extern u8 func##_negative(unsigned long *skb, int offset); \
73 	extern u8 func##_positive(unsigned long *skb, int offset)
74 
75 DECLARE_LOAD_FUNC(sk_load_word);
76 DECLARE_LOAD_FUNC(sk_load_half);
77 DECLARE_LOAD_FUNC(sk_load_byte);
78 
79 #endif
80 
81 #endif /* BPF_JIT_MIPS_OP_H */
82