treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 294
[linux-block.git] / kernel / bpf / disasm.c
CommitLineData
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1/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13
14#include <linux/bpf.h>
15
16#include "disasm.h"
17
18#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
19static const char * const func_id_str[] = {
20 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
21};
22#undef __BPF_FUNC_STR_FN
23
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DB
24static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
25 const struct bpf_insn *insn,
26 char *buff, size_t len)
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27{
28 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
29
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30 if (insn->src_reg != BPF_PSEUDO_CALL &&
31 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
32 func_id_str[insn->imm])
33 return func_id_str[insn->imm];
34
35 if (cbs && cbs->cb_call)
36 return cbs->cb_call(cbs->private_data, insn);
37
38 if (insn->src_reg == BPF_PSEUDO_CALL)
39 snprintf(buff, len, "%+d", insn->imm);
40
41 return buff;
42}
43
44static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
45 const struct bpf_insn *insn,
46 u64 full_imm, char *buff, size_t len)
47{
48 if (cbs && cbs->cb_imm)
49 return cbs->cb_imm(cbs->private_data, insn, full_imm);
50
51 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
52 return buff;
53}
54
55const char *func_id_name(int id)
56{
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57 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
58 return func_id_str[id];
59 else
60 return "unknown";
61}
62
63const char *const bpf_class_string[8] = {
64 [BPF_LD] = "ld",
65 [BPF_LDX] = "ldx",
66 [BPF_ST] = "st",
67 [BPF_STX] = "stx",
68 [BPF_ALU] = "alu",
69 [BPF_JMP] = "jmp",
56cbd82e 70 [BPF_JMP32] = "jmp32",
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71 [BPF_ALU64] = "alu64",
72};
73
74const char *const bpf_alu_string[16] = {
75 [BPF_ADD >> 4] = "+=",
76 [BPF_SUB >> 4] = "-=",
77 [BPF_MUL >> 4] = "*=",
78 [BPF_DIV >> 4] = "/=",
79 [BPF_OR >> 4] = "|=",
80 [BPF_AND >> 4] = "&=",
81 [BPF_LSH >> 4] = "<<=",
82 [BPF_RSH >> 4] = ">>=",
83 [BPF_NEG >> 4] = "neg",
84 [BPF_MOD >> 4] = "%=",
85 [BPF_XOR >> 4] = "^=",
86 [BPF_MOV >> 4] = "=",
87 [BPF_ARSH >> 4] = "s>>=",
88 [BPF_END >> 4] = "endian",
89};
90
91static const char *const bpf_ldst_string[] = {
92 [BPF_W >> 3] = "u32",
93 [BPF_H >> 3] = "u16",
94 [BPF_B >> 3] = "u8",
95 [BPF_DW >> 3] = "u64",
96};
97
98static const char *const bpf_jmp_string[16] = {
99 [BPF_JA >> 4] = "jmp",
100 [BPF_JEQ >> 4] = "==",
101 [BPF_JGT >> 4] = ">",
102 [BPF_JLT >> 4] = "<",
103 [BPF_JGE >> 4] = ">=",
104 [BPF_JLE >> 4] = "<=",
105 [BPF_JSET >> 4] = "&",
106 [BPF_JNE >> 4] = "!=",
107 [BPF_JSGT >> 4] = "s>",
108 [BPF_JSLT >> 4] = "s<",
109 [BPF_JSGE >> 4] = "s>=",
110 [BPF_JSLE >> 4] = "s<=",
111 [BPF_CALL >> 4] = "call",
112 [BPF_EXIT >> 4] = "exit",
113};
114
7105e828 115static void print_bpf_end_insn(bpf_insn_print_t verbose,
abe08840 116 void *private_data,
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117 const struct bpf_insn *insn)
118{
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119 verbose(private_data, "(%02x) r%d = %s%d r%d\n",
120 insn->code, insn->dst_reg,
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121 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
122 insn->imm, insn->dst_reg);
123}
124
7105e828 125void print_bpf_insn(const struct bpf_insn_cbs *cbs,
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DB
126 const struct bpf_insn *insn,
127 bool allow_ptr_leaks)
f4ac7e0b 128{
7105e828 129 const bpf_insn_print_t verbose = cbs->cb_print;
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130 u8 class = BPF_CLASS(insn->code);
131
132 if (class == BPF_ALU || class == BPF_ALU64) {
133 if (BPF_OP(insn->code) == BPF_END) {
134 if (class == BPF_ALU64)
abe08840 135 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
f4ac7e0b 136 else
abe08840 137 print_bpf_end_insn(verbose, cbs->private_data, insn);
f4ac7e0b 138 } else if (BPF_OP(insn->code) == BPF_NEG) {
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139 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
140 insn->code, class == BPF_ALU ? 'w' : 'r',
141 insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
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142 insn->dst_reg);
143 } else if (BPF_SRC(insn->code) == BPF_X) {
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144 verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
145 insn->code, class == BPF_ALU ? 'w' : 'r',
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146 insn->dst_reg,
147 bpf_alu_string[BPF_OP(insn->code) >> 4],
56cbd82e 148 class == BPF_ALU ? 'w' : 'r',
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149 insn->src_reg);
150 } else {
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151 verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
152 insn->code, class == BPF_ALU ? 'w' : 'r',
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153 insn->dst_reg,
154 bpf_alu_string[BPF_OP(insn->code) >> 4],
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155 insn->imm);
156 }
157 } else if (class == BPF_STX) {
158 if (BPF_MODE(insn->code) == BPF_MEM)
abe08840 159 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
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160 insn->code,
161 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
162 insn->dst_reg,
163 insn->off, insn->src_reg);
164 else if (BPF_MODE(insn->code) == BPF_XADD)
abe08840 165 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
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166 insn->code,
167 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
168 insn->dst_reg, insn->off,
169 insn->src_reg);
170 else
abe08840 171 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
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172 } else if (class == BPF_ST) {
173 if (BPF_MODE(insn->code) != BPF_MEM) {
abe08840 174 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
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175 return;
176 }
abe08840 177 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
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178 insn->code,
179 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
180 insn->dst_reg,
181 insn->off, insn->imm);
182 } else if (class == BPF_LDX) {
183 if (BPF_MODE(insn->code) != BPF_MEM) {
abe08840 184 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
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185 return;
186 }
abe08840 187 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
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188 insn->code, insn->dst_reg,
189 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
190 insn->src_reg, insn->off);
191 } else if (class == BPF_LD) {
192 if (BPF_MODE(insn->code) == BPF_ABS) {
abe08840 193 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
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194 insn->code,
195 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
196 insn->imm);
197 } else if (BPF_MODE(insn->code) == BPF_IND) {
abe08840 198 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
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199 insn->code,
200 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
201 insn->src_reg, insn->imm);
202 } else if (BPF_MODE(insn->code) == BPF_IMM &&
203 BPF_SIZE(insn->code) == BPF_DW) {
204 /* At this point, we already made sure that the second
205 * part of the ldimm64 insn is accessible.
206 */
207 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
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208 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
209 insn->src_reg == BPF_PSEUDO_MAP_VALUE;
7105e828 210 char tmp[64];
f4ac7e0b 211
d8eca5bb 212 if (is_ptr && !allow_ptr_leaks)
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213 imm = 0;
214
abe08840 215 verbose(cbs->private_data, "(%02x) r%d = %s\n",
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216 insn->code, insn->dst_reg,
217 __func_imm_name(cbs, insn, imm,
218 tmp, sizeof(tmp)));
f4ac7e0b 219 } else {
abe08840 220 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
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221 return;
222 }
56cbd82e 223 } else if (class == BPF_JMP32 || class == BPF_JMP) {
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224 u8 opcode = BPF_OP(insn->code);
225
226 if (opcode == BPF_CALL) {
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227 char tmp[64];
228
229 if (insn->src_reg == BPF_PSEUDO_CALL) {
abe08840 230 verbose(cbs->private_data, "(%02x) call pc%s\n",
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231 insn->code,
232 __func_get_name(cbs, insn,
233 tmp, sizeof(tmp)));
234 } else {
235 strcpy(tmp, "unknown");
abe08840 236 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
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237 __func_get_name(cbs, insn,
238 tmp, sizeof(tmp)),
239 insn->imm);
240 }
f4ac7e0b 241 } else if (insn->code == (BPF_JMP | BPF_JA)) {
abe08840 242 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
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243 insn->code, insn->off);
244 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
abe08840 245 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
f4ac7e0b 246 } else if (BPF_SRC(insn->code) == BPF_X) {
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247 verbose(cbs->private_data,
248 "(%02x) if %c%d %s %c%d goto pc%+d\n",
249 insn->code, class == BPF_JMP32 ? 'w' : 'r',
250 insn->dst_reg,
f4ac7e0b 251 bpf_jmp_string[BPF_OP(insn->code) >> 4],
56cbd82e 252 class == BPF_JMP32 ? 'w' : 'r',
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253 insn->src_reg, insn->off);
254 } else {
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255 verbose(cbs->private_data,
256 "(%02x) if %c%d %s 0x%x goto pc%+d\n",
257 insn->code, class == BPF_JMP32 ? 'w' : 'r',
258 insn->dst_reg,
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259 bpf_jmp_string[BPF_OP(insn->code) >> 4],
260 insn->imm, insn->off);
261 }
262 } else {
abe08840 263 verbose(cbs->private_data, "(%02x) %s\n",
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264 insn->code, bpf_class_string[class]);
265 }
266}