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1 /*
2  * bpf_jit32.h: BPF JIT compiler for PPC
3  *
4  * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
5  *
6  * Split from bpf_jit.h
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; version 2
11  * of the License.
12  */
13 #ifndef _BPF_JIT32_H
14 #define _BPF_JIT32_H
15 
16 #include "bpf_jit.h"
17 
18 #ifdef CONFIG_PPC64
19 #define BPF_PPC_STACK_R3_OFF	48
20 #define BPF_PPC_STACK_LOCALS	32
21 #define BPF_PPC_STACK_BASIC	(48+64)
22 #define BPF_PPC_STACK_SAVE	(18*8)
23 #define BPF_PPC_STACKFRAME	(BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \
24 				 BPF_PPC_STACK_SAVE)
25 #define BPF_PPC_SLOWPATH_FRAME	(48+64)
26 #else
27 #define BPF_PPC_STACK_R3_OFF	24
28 #define BPF_PPC_STACK_LOCALS	16
29 #define BPF_PPC_STACK_BASIC	(24+32)
30 #define BPF_PPC_STACK_SAVE	(18*4)
31 #define BPF_PPC_STACKFRAME	(BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \
32 				 BPF_PPC_STACK_SAVE)
33 #define BPF_PPC_SLOWPATH_FRAME	(24+32)
34 #endif
35 
36 #define REG_SZ         (BITS_PER_LONG/8)
37 
38 /*
39  * Generated code register usage:
40  *
41  * As normal PPC C ABI (e.g. r1=sp, r2=TOC), with:
42  *
43  * skb		r3	(Entry parameter)
44  * A register	r4
45  * X register	r5
46  * addr param	r6
47  * r7-r10	scratch
48  * skb->data	r14
49  * skb headlen	r15	(skb->len - skb->data_len)
50  * m[0]		r16
51  * m[...]	...
52  * m[15]	r31
53  */
54 #define r_skb		3
55 #define r_ret		3
56 #define r_A		4
57 #define r_X		5
58 #define r_addr		6
59 #define r_scratch1	7
60 #define r_scratch2	8
61 #define r_D		14
62 #define r_HL		15
63 #define r_M		16
64 
65 #ifndef __ASSEMBLY__
66 
67 /*
68  * Assembly helpers from arch/powerpc/net/bpf_jit.S:
69  */
70 #define DECLARE_LOAD_FUNC(func)	\
71 	extern u8 func[], func##_negative_offset[], func##_positive_offset[]
72 
73 DECLARE_LOAD_FUNC(sk_load_word);
74 DECLARE_LOAD_FUNC(sk_load_half);
75 DECLARE_LOAD_FUNC(sk_load_byte);
76 DECLARE_LOAD_FUNC(sk_load_byte_msh);
77 
78 #define PPC_LBZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LBZ(r, base, i);   \
79 		else {	PPC_ADDIS(r, base, IMM_HA(i));			      \
80 			PPC_LBZ(r, r, IMM_L(i)); } } while(0)
81 
82 #define PPC_LD_OFFS(r, base, i) do { if ((i) < 32768) PPC_LD(r, base, i);     \
83 		else {	PPC_ADDIS(r, base, IMM_HA(i));			      \
84 			PPC_LD(r, r, IMM_L(i)); } } while(0)
85 
86 #define PPC_LWZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LWZ(r, base, i);   \
87 		else {	PPC_ADDIS(r, base, IMM_HA(i));			      \
88 			PPC_LWZ(r, r, IMM_L(i)); } } while(0)
89 
90 #define PPC_LHZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LHZ(r, base, i);   \
91 		else {	PPC_ADDIS(r, base, IMM_HA(i));			      \
92 			PPC_LHZ(r, r, IMM_L(i)); } } while(0)
93 
94 #ifdef CONFIG_PPC64
95 #define PPC_LL_OFFS(r, base, i) do { PPC_LD_OFFS(r, base, i); } while(0)
96 #else
97 #define PPC_LL_OFFS(r, base, i) do { PPC_LWZ_OFFS(r, base, i); } while(0)
98 #endif
99 
100 #ifdef CONFIG_SMP
101 #ifdef CONFIG_PPC64
102 #define PPC_BPF_LOAD_CPU(r)		\
103 	do { BUILD_BUG_ON(FIELD_SIZEOF(struct paca_struct, paca_index) != 2);	\
104 		PPC_LHZ_OFFS(r, 13, offsetof(struct paca_struct, paca_index));	\
105 	} while (0)
106 #else
107 #define PPC_BPF_LOAD_CPU(r)     \
108 	do { BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4);		\
109 		PPC_LHZ_OFFS(r, (1 & ~(THREAD_SIZE - 1)),			\
110 				offsetof(struct thread_info, cpu));		\
111 	} while(0)
112 #endif
113 #else
114 #define PPC_BPF_LOAD_CPU(r) do { PPC_LI(r, 0); } while(0)
115 #endif
116 
117 #define PPC_LHBRX_OFFS(r, base, i) \
118 		do { PPC_LI32(r, i); PPC_LHBRX(r, r, base); } while(0)
119 #ifdef __LITTLE_ENDIAN__
120 #define PPC_NTOHS_OFFS(r, base, i)	PPC_LHBRX_OFFS(r, base, i)
121 #else
122 #define PPC_NTOHS_OFFS(r, base, i)	PPC_LHZ_OFFS(r, base, i)
123 #endif
124 
125 #define PPC_BPF_LL(r, base, i) do { PPC_LWZ(r, base, i); } while(0)
126 #define PPC_BPF_STL(r, base, i) do { PPC_STW(r, base, i); } while(0)
127 #define PPC_BPF_STLU(r, base, i) do { PPC_STWU(r, base, i); } while(0)
128 
129 #define SEEN_DATAREF 0x10000 /* might call external helpers */
130 #define SEEN_XREG    0x20000 /* X reg is used */
131 #define SEEN_MEM     0x40000 /* SEEN_MEM+(1<<n) = use mem[n] for temporary
132 			      * storage */
133 #define SEEN_MEM_MSK 0x0ffff
134 
135 struct codegen_context {
136 	unsigned int seen;
137 	unsigned int idx;
138 	int pc_ret0; /* bpf index of first RET #0 instruction (if any) */
139 };
140 
141 #endif
142 
143 #endif
144