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Linux kernel mirror (for testing)
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1/* bpf_jit.h: BPF JIT compiler for PPC64
2 *
3 * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; version 2
8 * of the License.
9 */
10#ifndef _BPF_JIT_H
11#define _BPF_JIT_H
12
13#define BPF_PPC_STACK_LOCALS 32
14#define BPF_PPC_STACK_BASIC (48+64)
15#define BPF_PPC_STACK_SAVE (18*8)
16#define BPF_PPC_STACKFRAME (BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \
17 BPF_PPC_STACK_SAVE)
18#define BPF_PPC_SLOWPATH_FRAME (48+64)
19
20/*
21 * Generated code register usage:
22 *
23 * As normal PPC C ABI (e.g. r1=sp, r2=TOC), with:
24 *
25 * skb r3 (Entry parameter)
26 * A register r4
27 * X register r5
28 * addr param r6
29 * r7-r10 scratch
30 * skb->data r14
31 * skb headlen r15 (skb->len - skb->data_len)
32 * m[0] r16
33 * m[...] ...
34 * m[15] r31
35 */
36#define r_skb 3
37#define r_ret 3
38#define r_A 4
39#define r_X 5
40#define r_addr 6
41#define r_scratch1 7
42#define r_D 14
43#define r_HL 15
44#define r_M 16
45
46#ifndef __ASSEMBLY__
47
48/*
49 * Assembly helpers from arch/powerpc/net/bpf_jit.S:
50 */
51#define DECLARE_LOAD_FUNC(func) \
52 extern u8 func[], func##_negative_offset[], func##_positive_offset[]
53
54DECLARE_LOAD_FUNC(sk_load_word);
55DECLARE_LOAD_FUNC(sk_load_half);
56DECLARE_LOAD_FUNC(sk_load_byte);
57DECLARE_LOAD_FUNC(sk_load_byte_msh);
58
59#define FUNCTION_DESCR_SIZE 24
60
61/*
62 * 16-bit immediate helper macros: HA() is for use with sign-extending instrs
63 * (e.g. LD, ADDI). If the bottom 16 bits is "-ve", add another bit into the
64 * top half to negate the effect (i.e. 0xffff + 1 = 0x(1)0000).
65 */
66#define IMM_H(i) ((uintptr_t)(i)>>16)
67#define IMM_HA(i) (((uintptr_t)(i)>>16) + \
68 (((uintptr_t)(i) & 0x8000) >> 15))
69#define IMM_L(i) ((uintptr_t)(i) & 0xffff)
70
71#define PLANT_INSTR(d, idx, instr) \
72 do { if (d) { (d)[idx] = instr; } idx++; } while (0)
73#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr)
74
75#define PPC_NOP() EMIT(PPC_INST_NOP)
76#define PPC_BLR() EMIT(PPC_INST_BLR)
77#define PPC_BLRL() EMIT(PPC_INST_BLRL)
78#define PPC_MTLR(r) EMIT(PPC_INST_MTLR | ___PPC_RT(r))
79#define PPC_ADDI(d, a, i) EMIT(PPC_INST_ADDI | ___PPC_RT(d) | \
80 ___PPC_RA(a) | IMM_L(i))
81#define PPC_MR(d, a) PPC_OR(d, a, a)
82#define PPC_LI(r, i) PPC_ADDI(r, 0, i)
83#define PPC_ADDIS(d, a, i) EMIT(PPC_INST_ADDIS | \
84 ___PPC_RS(d) | ___PPC_RA(a) | IMM_L(i))
85#define PPC_LIS(r, i) PPC_ADDIS(r, 0, i)
86#define PPC_STD(r, base, i) EMIT(PPC_INST_STD | ___PPC_RS(r) | \
87 ___PPC_RA(base) | ((i) & 0xfffc))
88
89#define PPC_LD(r, base, i) EMIT(PPC_INST_LD | ___PPC_RT(r) | \
90 ___PPC_RA(base) | IMM_L(i))
91#define PPC_LWZ(r, base, i) EMIT(PPC_INST_LWZ | ___PPC_RT(r) | \
92 ___PPC_RA(base) | IMM_L(i))
93#define PPC_LHZ(r, base, i) EMIT(PPC_INST_LHZ | ___PPC_RT(r) | \
94 ___PPC_RA(base) | IMM_L(i))
95/* Convenience helpers for the above with 'far' offsets: */
96#define PPC_LD_OFFS(r, base, i) do { if ((i) < 32768) PPC_LD(r, base, i); \
97 else { PPC_ADDIS(r, base, IMM_HA(i)); \
98 PPC_LD(r, r, IMM_L(i)); } } while(0)
99
100#define PPC_LWZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LWZ(r, base, i); \
101 else { PPC_ADDIS(r, base, IMM_HA(i)); \
102 PPC_LWZ(r, r, IMM_L(i)); } } while(0)
103
104#define PPC_LHZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LHZ(r, base, i); \
105 else { PPC_ADDIS(r, base, IMM_HA(i)); \
106 PPC_LHZ(r, r, IMM_L(i)); } } while(0)
107
108#define PPC_CMPWI(a, i) EMIT(PPC_INST_CMPWI | ___PPC_RA(a) | IMM_L(i))
109#define PPC_CMPDI(a, i) EMIT(PPC_INST_CMPDI | ___PPC_RA(a) | IMM_L(i))
110#define PPC_CMPLWI(a, i) EMIT(PPC_INST_CMPLWI | ___PPC_RA(a) | IMM_L(i))
111#define PPC_CMPLW(a, b) EMIT(PPC_INST_CMPLW | ___PPC_RA(a) | ___PPC_RB(b))
112
113#define PPC_SUB(d, a, b) EMIT(PPC_INST_SUB | ___PPC_RT(d) | \
114 ___PPC_RB(a) | ___PPC_RA(b))
115#define PPC_ADD(d, a, b) EMIT(PPC_INST_ADD | ___PPC_RT(d) | \
116 ___PPC_RA(a) | ___PPC_RB(b))
117#define PPC_MUL(d, a, b) EMIT(PPC_INST_MULLW | ___PPC_RT(d) | \
118 ___PPC_RA(a) | ___PPC_RB(b))
119#define PPC_MULHWU(d, a, b) EMIT(PPC_INST_MULHWU | ___PPC_RT(d) | \
120 ___PPC_RA(a) | ___PPC_RB(b))
121#define PPC_MULI(d, a, i) EMIT(PPC_INST_MULLI | ___PPC_RT(d) | \
122 ___PPC_RA(a) | IMM_L(i))
123#define PPC_DIVWU(d, a, b) EMIT(PPC_INST_DIVWU | ___PPC_RT(d) | \
124 ___PPC_RA(a) | ___PPC_RB(b))
125#define PPC_AND(d, a, b) EMIT(PPC_INST_AND | ___PPC_RA(d) | \
126 ___PPC_RS(a) | ___PPC_RB(b))
127#define PPC_ANDI(d, a, i) EMIT(PPC_INST_ANDI | ___PPC_RA(d) | \
128 ___PPC_RS(a) | IMM_L(i))
129#define PPC_AND_DOT(d, a, b) EMIT(PPC_INST_ANDDOT | ___PPC_RA(d) | \
130 ___PPC_RS(a) | ___PPC_RB(b))
131#define PPC_OR(d, a, b) EMIT(PPC_INST_OR | ___PPC_RA(d) | \
132 ___PPC_RS(a) | ___PPC_RB(b))
133#define PPC_ORI(d, a, i) EMIT(PPC_INST_ORI | ___PPC_RA(d) | \
134 ___PPC_RS(a) | IMM_L(i))
135#define PPC_ORIS(d, a, i) EMIT(PPC_INST_ORIS | ___PPC_RA(d) | \
136 ___PPC_RS(a) | IMM_L(i))
137#define PPC_XOR(d, a, b) EMIT(PPC_INST_XOR | ___PPC_RA(d) | \
138 ___PPC_RS(a) | ___PPC_RB(b))
139#define PPC_XORI(d, a, i) EMIT(PPC_INST_XORI | ___PPC_RA(d) | \
140 ___PPC_RS(a) | IMM_L(i))
141#define PPC_XORIS(d, a, i) EMIT(PPC_INST_XORIS | ___PPC_RA(d) | \
142 ___PPC_RS(a) | IMM_L(i))
143#define PPC_SLW(d, a, s) EMIT(PPC_INST_SLW | ___PPC_RA(d) | \
144 ___PPC_RS(a) | ___PPC_RB(s))
145#define PPC_SRW(d, a, s) EMIT(PPC_INST_SRW | ___PPC_RA(d) | \
146 ___PPC_RS(a) | ___PPC_RB(s))
147/* slwi = rlwinm Rx, Ry, n, 0, 31-n */
148#define PPC_SLWI(d, a, i) EMIT(PPC_INST_RLWINM | ___PPC_RA(d) | \
149 ___PPC_RS(a) | __PPC_SH(i) | \
150 __PPC_MB(0) | __PPC_ME(31-(i)))
151/* srwi = rlwinm Rx, Ry, 32-n, n, 31 */
152#define PPC_SRWI(d, a, i) EMIT(PPC_INST_RLWINM | ___PPC_RA(d) | \
153 ___PPC_RS(a) | __PPC_SH(32-(i)) | \
154 __PPC_MB(i) | __PPC_ME(31))
155/* sldi = rldicr Rx, Ry, n, 63-n */
156#define PPC_SLDI(d, a, i) EMIT(PPC_INST_RLDICR | ___PPC_RA(d) | \
157 ___PPC_RS(a) | __PPC_SH(i) | \
158 __PPC_MB(63-(i)) | (((i) & 0x20) >> 4))
159#define PPC_NEG(d, a) EMIT(PPC_INST_NEG | ___PPC_RT(d) | ___PPC_RA(a))
160
161/* Long jump; (unconditional 'branch') */
162#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \
163 (((dest) - (ctx->idx * 4)) & 0x03fffffc))
164/* "cond" here covers BO:BI fields. */
165#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \
166 (((cond) & 0x3ff) << 16) | \
167 (((dest) - (ctx->idx * 4)) & \
168 0xfffc))
169#define PPC_LI32(d, i) do { PPC_LI(d, IMM_L(i)); \
170 if ((u32)(uintptr_t)(i) >= 32768) { \
171 PPC_ADDIS(d, d, IMM_HA(i)); \
172 } } while(0)
173#define PPC_LI64(d, i) do { \
174 if (!((uintptr_t)(i) & 0xffffffff00000000ULL)) \
175 PPC_LI32(d, i); \
176 else { \
177 PPC_LIS(d, ((uintptr_t)(i) >> 48)); \
178 if ((uintptr_t)(i) & 0x0000ffff00000000ULL) \
179 PPC_ORI(d, d, \
180 ((uintptr_t)(i) >> 32) & 0xffff); \
181 PPC_SLDI(d, d, 32); \
182 if ((uintptr_t)(i) & 0x00000000ffff0000ULL) \
183 PPC_ORIS(d, d, \
184 ((uintptr_t)(i) >> 16) & 0xffff); \
185 if ((uintptr_t)(i) & 0x000000000000ffffULL) \
186 PPC_ORI(d, d, (uintptr_t)(i) & 0xffff); \
187 } } while (0);
188
189static inline bool is_nearbranch(int offset)
190{
191 return (offset < 32768) && (offset >= -32768);
192}
193
194/*
195 * The fly in the ointment of code size changing from pass to pass is
196 * avoided by padding the short branch case with a NOP. If code size differs
197 * with different branch reaches we will have the issue of code moving from
198 * one pass to the next and will need a few passes to converge on a stable
199 * state.
200 */
201#define PPC_BCC(cond, dest) do { \
202 if (is_nearbranch((dest) - (ctx->idx * 4))) { \
203 PPC_BCC_SHORT(cond, dest); \
204 PPC_NOP(); \
205 } else { \
206 /* Flip the 'T or F' bit to invert comparison */ \
207 PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, (ctx->idx+2)*4); \
208 PPC_JMP(dest); \
209 } } while(0)
210
211/* To create a branch condition, select a bit of cr0... */
212#define CR0_LT 0
213#define CR0_GT 1
214#define CR0_EQ 2
215/* ...and modify BO[3] */
216#define COND_CMP_TRUE 0x100
217#define COND_CMP_FALSE 0x000
218/* Together, they make all required comparisons: */
219#define COND_GT (CR0_GT | COND_CMP_TRUE)
220#define COND_GE (CR0_LT | COND_CMP_FALSE)
221#define COND_EQ (CR0_EQ | COND_CMP_TRUE)
222#define COND_NE (CR0_EQ | COND_CMP_FALSE)
223#define COND_LT (CR0_LT | COND_CMP_TRUE)
224
225#define SEEN_DATAREF 0x10000 /* might call external helpers */
226#define SEEN_XREG 0x20000 /* X reg is used */
227#define SEEN_MEM 0x40000 /* SEEN_MEM+(1<<n) = use mem[n] for temporary
228 * storage */
229#define SEEN_MEM_MSK 0x0ffff
230
231struct codegen_context {
232 unsigned int seen;
233 unsigned int idx;
234 int pc_ret0; /* bpf index of first RET #0 instruction (if any) */
235};
236
237#endif
238
239#endif