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0a14842f ED |
1 | /* bpf_jit_comp.c : BPF JIT compiler |
2 | * | |
3 | * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com) | |
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 | #include <linux/moduleloader.h> | |
11 | #include <asm/cacheflush.h> | |
12 | #include <linux/netdevice.h> | |
13 | #include <linux/filter.h> | |
855ddb56 | 14 | #include <linux/if_vlan.h> |
0a14842f ED |
15 | |
16 | /* | |
17 | * Conventions : | |
18 | * EAX : BPF A accumulator | |
19 | * EBX : BPF X accumulator | |
20 | * RDI : pointer to skb (first argument given to JIT function) | |
21 | * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n) | |
22 | * ECX,EDX,ESI : scratch registers | |
23 | * r9d : skb->len - skb->data_len (headlen) | |
24 | * r8 : skb->data | |
25 | * -8(RBP) : saved RBX value | |
26 | * -16(RBP)..-80(RBP) : BPF_MEMWORDS values | |
27 | */ | |
28 | int bpf_jit_enable __read_mostly; | |
29 | ||
30 | /* | |
31 | * assembly code in arch/x86/net/bpf_jit.S | |
32 | */ | |
33 | extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[]; | |
a998d434 JS |
34 | extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[]; |
35 | extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[]; | |
36 | extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[]; | |
37 | extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[]; | |
0a14842f ED |
38 | |
39 | static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) | |
40 | { | |
41 | if (len == 1) | |
42 | *ptr = bytes; | |
43 | else if (len == 2) | |
44 | *(u16 *)ptr = bytes; | |
45 | else { | |
46 | *(u32 *)ptr = bytes; | |
47 | barrier(); | |
48 | } | |
49 | return ptr + len; | |
50 | } | |
51 | ||
52 | #define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0) | |
53 | ||
54 | #define EMIT1(b1) EMIT(b1, 1) | |
55 | #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2) | |
56 | #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3) | |
57 | #define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4) | |
58 | #define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0) | |
59 | ||
60 | #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */ | |
61 | #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */ | |
62 | ||
63 | static inline bool is_imm8(int value) | |
64 | { | |
65 | return value <= 127 && value >= -128; | |
66 | } | |
67 | ||
68 | static inline bool is_near(int offset) | |
69 | { | |
70 | return offset <= 127 && offset >= -128; | |
71 | } | |
72 | ||
73 | #define EMIT_JMP(offset) \ | |
74 | do { \ | |
75 | if (offset) { \ | |
76 | if (is_near(offset)) \ | |
77 | EMIT2(0xeb, offset); /* jmp .+off8 */ \ | |
78 | else \ | |
79 | EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \ | |
80 | } \ | |
81 | } while (0) | |
82 | ||
83 | /* list of x86 cond jumps opcodes (. + s8) | |
84 | * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32) | |
85 | */ | |
86 | #define X86_JB 0x72 | |
87 | #define X86_JAE 0x73 | |
88 | #define X86_JE 0x74 | |
89 | #define X86_JNE 0x75 | |
90 | #define X86_JBE 0x76 | |
91 | #define X86_JA 0x77 | |
92 | ||
93 | #define EMIT_COND_JMP(op, offset) \ | |
94 | do { \ | |
95 | if (is_near(offset)) \ | |
96 | EMIT2(op, offset); /* jxx .+off8 */ \ | |
97 | else { \ | |
98 | EMIT2(0x0f, op + 0x10); \ | |
99 | EMIT(offset, 4); /* jxx .+off32 */ \ | |
100 | } \ | |
101 | } while (0) | |
102 | ||
103 | #define COND_SEL(CODE, TOP, FOP) \ | |
104 | case CODE: \ | |
105 | t_op = TOP; \ | |
106 | f_op = FOP; \ | |
107 | goto cond_branch | |
108 | ||
109 | ||
110 | #define SEEN_DATAREF 1 /* might call external helpers */ | |
111 | #define SEEN_XREG 2 /* ebx is used */ | |
112 | #define SEEN_MEM 4 /* use mem[] for temporary storage */ | |
113 | ||
114 | static inline void bpf_flush_icache(void *start, void *end) | |
115 | { | |
116 | mm_segment_t old_fs = get_fs(); | |
117 | ||
118 | set_fs(KERNEL_DS); | |
119 | smp_wmb(); | |
120 | flush_icache_range((unsigned long)start, (unsigned long)end); | |
121 | set_fs(old_fs); | |
122 | } | |
123 | ||
a998d434 JS |
124 | #define CHOOSE_LOAD_FUNC(K, func) \ |
125 | ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset) | |
0a14842f ED |
126 | |
127 | void bpf_jit_compile(struct sk_filter *fp) | |
128 | { | |
129 | u8 temp[64]; | |
130 | u8 *prog; | |
131 | unsigned int proglen, oldproglen = 0; | |
132 | int ilen, i; | |
133 | int t_offset, f_offset; | |
134 | u8 t_op, f_op, seen = 0, pass; | |
135 | u8 *image = NULL; | |
136 | u8 *func; | |
137 | int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */ | |
138 | unsigned int cleanup_addr; /* epilogue code offset */ | |
139 | unsigned int *addrs; | |
140 | const struct sock_filter *filter = fp->insns; | |
141 | int flen = fp->len; | |
142 | ||
143 | if (!bpf_jit_enable) | |
144 | return; | |
145 | ||
146 | addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL); | |
147 | if (addrs == NULL) | |
148 | return; | |
149 | ||
150 | /* Before first pass, make a rough estimation of addrs[] | |
151 | * each bpf instruction is translated to less than 64 bytes | |
152 | */ | |
153 | for (proglen = 0, i = 0; i < flen; i++) { | |
154 | proglen += 64; | |
155 | addrs[i] = proglen; | |
156 | } | |
157 | cleanup_addr = proglen; /* epilogue address */ | |
158 | ||
159 | for (pass = 0; pass < 10; pass++) { | |
d00a9dd2 | 160 | u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen; |
0a14842f ED |
161 | /* no prologue/epilogue for trivial filters (RET something) */ |
162 | proglen = 0; | |
163 | prog = temp; | |
164 | ||
d00a9dd2 | 165 | if (seen_or_pass0) { |
0a14842f ED |
166 | EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */ |
167 | EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */ | |
168 | /* note : must save %rbx in case bpf_error is hit */ | |
d00a9dd2 | 169 | if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF)) |
0a14842f | 170 | EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */ |
d00a9dd2 | 171 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
172 | CLEAR_X(); /* make sure we dont leek kernel memory */ |
173 | ||
174 | /* | |
175 | * If this filter needs to access skb data, | |
176 | * loads r9 and r8 with : | |
177 | * r9 = skb->len - skb->data_len | |
178 | * r8 = skb->data | |
179 | */ | |
d00a9dd2 | 180 | if (seen_or_pass0 & SEEN_DATAREF) { |
0a14842f ED |
181 | if (offsetof(struct sk_buff, len) <= 127) |
182 | /* mov off8(%rdi),%r9d */ | |
183 | EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len)); | |
184 | else { | |
185 | /* mov off32(%rdi),%r9d */ | |
186 | EMIT3(0x44, 0x8b, 0x8f); | |
187 | EMIT(offsetof(struct sk_buff, len), 4); | |
188 | } | |
189 | if (is_imm8(offsetof(struct sk_buff, data_len))) | |
190 | /* sub off8(%rdi),%r9d */ | |
191 | EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len)); | |
192 | else { | |
193 | EMIT3(0x44, 0x2b, 0x8f); | |
194 | EMIT(offsetof(struct sk_buff, data_len), 4); | |
195 | } | |
196 | ||
197 | if (is_imm8(offsetof(struct sk_buff, data))) | |
198 | /* mov off8(%rdi),%r8 */ | |
199 | EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data)); | |
200 | else { | |
201 | /* mov off32(%rdi),%r8 */ | |
202 | EMIT3(0x4c, 0x8b, 0x87); | |
203 | EMIT(offsetof(struct sk_buff, data), 4); | |
204 | } | |
205 | } | |
206 | } | |
207 | ||
208 | switch (filter[0].code) { | |
209 | case BPF_S_RET_K: | |
210 | case BPF_S_LD_W_LEN: | |
211 | case BPF_S_ANC_PROTOCOL: | |
212 | case BPF_S_ANC_IFINDEX: | |
213 | case BPF_S_ANC_MARK: | |
214 | case BPF_S_ANC_RXHASH: | |
215 | case BPF_S_ANC_CPU: | |
855ddb56 ED |
216 | case BPF_S_ANC_VLAN_TAG: |
217 | case BPF_S_ANC_VLAN_TAG_PRESENT: | |
0a14842f ED |
218 | case BPF_S_ANC_QUEUE: |
219 | case BPF_S_LD_W_ABS: | |
220 | case BPF_S_LD_H_ABS: | |
221 | case BPF_S_LD_B_ABS: | |
222 | /* first instruction sets A register (or is RET 'constant') */ | |
223 | break; | |
224 | default: | |
225 | /* make sure we dont leak kernel information to user */ | |
226 | CLEAR_A(); /* A = 0 */ | |
227 | } | |
228 | ||
229 | for (i = 0; i < flen; i++) { | |
230 | unsigned int K = filter[i].k; | |
231 | ||
232 | switch (filter[i].code) { | |
233 | case BPF_S_ALU_ADD_X: /* A += X; */ | |
234 | seen |= SEEN_XREG; | |
235 | EMIT2(0x01, 0xd8); /* add %ebx,%eax */ | |
236 | break; | |
237 | case BPF_S_ALU_ADD_K: /* A += K; */ | |
238 | if (!K) | |
239 | break; | |
240 | if (is_imm8(K)) | |
241 | EMIT3(0x83, 0xc0, K); /* add imm8,%eax */ | |
242 | else | |
243 | EMIT1_off32(0x05, K); /* add imm32,%eax */ | |
244 | break; | |
245 | case BPF_S_ALU_SUB_X: /* A -= X; */ | |
246 | seen |= SEEN_XREG; | |
247 | EMIT2(0x29, 0xd8); /* sub %ebx,%eax */ | |
248 | break; | |
249 | case BPF_S_ALU_SUB_K: /* A -= K */ | |
250 | if (!K) | |
251 | break; | |
252 | if (is_imm8(K)) | |
253 | EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */ | |
254 | else | |
255 | EMIT1_off32(0x2d, K); /* sub imm32,%eax */ | |
256 | break; | |
257 | case BPF_S_ALU_MUL_X: /* A *= X; */ | |
258 | seen |= SEEN_XREG; | |
259 | EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */ | |
260 | break; | |
261 | case BPF_S_ALU_MUL_K: /* A *= K */ | |
262 | if (is_imm8(K)) | |
263 | EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */ | |
264 | else { | |
265 | EMIT2(0x69, 0xc0); /* imul imm32,%eax */ | |
266 | EMIT(K, 4); | |
267 | } | |
268 | break; | |
269 | case BPF_S_ALU_DIV_X: /* A /= X; */ | |
270 | seen |= SEEN_XREG; | |
271 | EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ | |
d00a9dd2 ED |
272 | if (pc_ret0 > 0) { |
273 | /* addrs[pc_ret0 - 1] is start address of target | |
274 | * (addrs[i] - 4) is the address following this jmp | |
275 | * ("xor %edx,%edx; div %ebx" being 4 bytes long) | |
276 | */ | |
277 | EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] - | |
278 | (addrs[i] - 4)); | |
279 | } else { | |
0a14842f ED |
280 | EMIT_COND_JMP(X86_JNE, 2 + 5); |
281 | CLEAR_A(); | |
282 | EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */ | |
283 | } | |
284 | EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */ | |
285 | break; | |
280050cc ED |
286 | case BPF_S_ALU_MOD_X: /* A %= X; */ |
287 | seen |= SEEN_XREG; | |
288 | EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ | |
289 | if (pc_ret0 > 0) { | |
290 | /* addrs[pc_ret0 - 1] is start address of target | |
291 | * (addrs[i] - 6) is the address following this jmp | |
292 | * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long) | |
293 | */ | |
294 | EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] - | |
295 | (addrs[i] - 6)); | |
296 | } else { | |
297 | EMIT_COND_JMP(X86_JNE, 2 + 5); | |
298 | CLEAR_A(); | |
299 | EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */ | |
300 | } | |
301 | EMIT2(0x31, 0xd2); /* xor %edx,%edx */ | |
302 | EMIT2(0xf7, 0xf3); /* div %ebx */ | |
303 | EMIT2(0x89, 0xd0); /* mov %edx,%eax */ | |
304 | break; | |
305 | case BPF_S_ALU_MOD_K: /* A %= K; */ | |
306 | EMIT2(0x31, 0xd2); /* xor %edx,%edx */ | |
307 | EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */ | |
308 | EMIT2(0xf7, 0xf1); /* div %ecx */ | |
309 | EMIT2(0x89, 0xd0); /* mov %edx,%eax */ | |
310 | break; | |
0a14842f ED |
311 | case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */ |
312 | EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */ | |
313 | EMIT(K, 4); | |
314 | EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */ | |
315 | break; | |
316 | case BPF_S_ALU_AND_X: | |
317 | seen |= SEEN_XREG; | |
318 | EMIT2(0x21, 0xd8); /* and %ebx,%eax */ | |
319 | break; | |
320 | case BPF_S_ALU_AND_K: | |
321 | if (K >= 0xFFFFFF00) { | |
322 | EMIT2(0x24, K & 0xFF); /* and imm8,%al */ | |
323 | } else if (K >= 0xFFFF0000) { | |
324 | EMIT2(0x66, 0x25); /* and imm16,%ax */ | |
1d24fb36 | 325 | EMIT(K, 2); |
0a14842f ED |
326 | } else { |
327 | EMIT1_off32(0x25, K); /* and imm32,%eax */ | |
328 | } | |
329 | break; | |
330 | case BPF_S_ALU_OR_X: | |
331 | seen |= SEEN_XREG; | |
332 | EMIT2(0x09, 0xd8); /* or %ebx,%eax */ | |
333 | break; | |
334 | case BPF_S_ALU_OR_K: | |
335 | if (is_imm8(K)) | |
336 | EMIT3(0x83, 0xc8, K); /* or imm8,%eax */ | |
337 | else | |
338 | EMIT1_off32(0x0d, K); /* or imm32,%eax */ | |
4bfaddf1 ED |
339 | break; |
340 | case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */ | |
82c93fcc | 341 | case BPF_S_ALU_XOR_X: |
4bfaddf1 ED |
342 | seen |= SEEN_XREG; |
343 | EMIT2(0x31, 0xd8); /* xor %ebx,%eax */ | |
82c93fcc DB |
344 | break; |
345 | case BPF_S_ALU_XOR_K: /* A ^= K; */ | |
346 | if (K == 0) | |
347 | break; | |
348 | if (is_imm8(K)) | |
349 | EMIT3(0x83, 0xf0, K); /* xor imm8,%eax */ | |
350 | else | |
351 | EMIT1_off32(0x35, K); /* xor imm32,%eax */ | |
0a14842f ED |
352 | break; |
353 | case BPF_S_ALU_LSH_X: /* A <<= X; */ | |
354 | seen |= SEEN_XREG; | |
355 | EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */ | |
356 | break; | |
357 | case BPF_S_ALU_LSH_K: | |
358 | if (K == 0) | |
359 | break; | |
360 | else if (K == 1) | |
361 | EMIT2(0xd1, 0xe0); /* shl %eax */ | |
362 | else | |
363 | EMIT3(0xc1, 0xe0, K); | |
364 | break; | |
365 | case BPF_S_ALU_RSH_X: /* A >>= X; */ | |
366 | seen |= SEEN_XREG; | |
367 | EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */ | |
368 | break; | |
369 | case BPF_S_ALU_RSH_K: /* A >>= K; */ | |
370 | if (K == 0) | |
371 | break; | |
372 | else if (K == 1) | |
373 | EMIT2(0xd1, 0xe8); /* shr %eax */ | |
374 | else | |
375 | EMIT3(0xc1, 0xe8, K); | |
376 | break; | |
377 | case BPF_S_ALU_NEG: | |
378 | EMIT2(0xf7, 0xd8); /* neg %eax */ | |
379 | break; | |
380 | case BPF_S_RET_K: | |
381 | if (!K) { | |
382 | if (pc_ret0 == -1) | |
383 | pc_ret0 = i; | |
384 | CLEAR_A(); | |
385 | } else { | |
386 | EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ | |
387 | } | |
388 | /* fallinto */ | |
389 | case BPF_S_RET_A: | |
d00a9dd2 | 390 | if (seen_or_pass0) { |
0a14842f ED |
391 | if (i != flen - 1) { |
392 | EMIT_JMP(cleanup_addr - addrs[i]); | |
393 | break; | |
394 | } | |
d00a9dd2 | 395 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
396 | EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */ |
397 | EMIT1(0xc9); /* leaveq */ | |
398 | } | |
399 | EMIT1(0xc3); /* ret */ | |
400 | break; | |
401 | case BPF_S_MISC_TAX: /* X = A */ | |
402 | seen |= SEEN_XREG; | |
403 | EMIT2(0x89, 0xc3); /* mov %eax,%ebx */ | |
404 | break; | |
405 | case BPF_S_MISC_TXA: /* A = X */ | |
406 | seen |= SEEN_XREG; | |
407 | EMIT2(0x89, 0xd8); /* mov %ebx,%eax */ | |
408 | break; | |
409 | case BPF_S_LD_IMM: /* A = K */ | |
410 | if (!K) | |
411 | CLEAR_A(); | |
412 | else | |
413 | EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ | |
414 | break; | |
415 | case BPF_S_LDX_IMM: /* X = K */ | |
416 | seen |= SEEN_XREG; | |
417 | if (!K) | |
418 | CLEAR_X(); | |
419 | else | |
420 | EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */ | |
421 | break; | |
422 | case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */ | |
423 | seen |= SEEN_MEM; | |
424 | EMIT3(0x8b, 0x45, 0xf0 - K*4); | |
425 | break; | |
426 | case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */ | |
427 | seen |= SEEN_XREG | SEEN_MEM; | |
428 | EMIT3(0x8b, 0x5d, 0xf0 - K*4); | |
429 | break; | |
430 | case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */ | |
431 | seen |= SEEN_MEM; | |
432 | EMIT3(0x89, 0x45, 0xf0 - K*4); | |
433 | break; | |
434 | case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */ | |
435 | seen |= SEEN_XREG | SEEN_MEM; | |
436 | EMIT3(0x89, 0x5d, 0xf0 - K*4); | |
437 | break; | |
438 | case BPF_S_LD_W_LEN: /* A = skb->len; */ | |
439 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); | |
440 | if (is_imm8(offsetof(struct sk_buff, len))) | |
441 | /* mov off8(%rdi),%eax */ | |
442 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len)); | |
443 | else { | |
444 | EMIT2(0x8b, 0x87); | |
445 | EMIT(offsetof(struct sk_buff, len), 4); | |
446 | } | |
447 | break; | |
448 | case BPF_S_LDX_W_LEN: /* X = skb->len; */ | |
449 | seen |= SEEN_XREG; | |
450 | if (is_imm8(offsetof(struct sk_buff, len))) | |
451 | /* mov off8(%rdi),%ebx */ | |
452 | EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len)); | |
453 | else { | |
454 | EMIT2(0x8b, 0x9f); | |
455 | EMIT(offsetof(struct sk_buff, len), 4); | |
456 | } | |
457 | break; | |
458 | case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */ | |
459 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); | |
460 | if (is_imm8(offsetof(struct sk_buff, protocol))) { | |
461 | /* movzwl off8(%rdi),%eax */ | |
462 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol)); | |
463 | } else { | |
464 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
465 | EMIT(offsetof(struct sk_buff, protocol), 4); | |
466 | } | |
467 | EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */ | |
468 | break; | |
469 | case BPF_S_ANC_IFINDEX: | |
470 | if (is_imm8(offsetof(struct sk_buff, dev))) { | |
471 | /* movq off8(%rdi),%rax */ | |
472 | EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev)); | |
473 | } else { | |
474 | EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */ | |
475 | EMIT(offsetof(struct sk_buff, dev), 4); | |
476 | } | |
477 | EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */ | |
478 | EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6)); | |
479 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); | |
480 | EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */ | |
481 | EMIT(offsetof(struct net_device, ifindex), 4); | |
482 | break; | |
483 | case BPF_S_ANC_MARK: | |
484 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); | |
485 | if (is_imm8(offsetof(struct sk_buff, mark))) { | |
486 | /* mov off8(%rdi),%eax */ | |
487 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark)); | |
488 | } else { | |
489 | EMIT2(0x8b, 0x87); | |
490 | EMIT(offsetof(struct sk_buff, mark), 4); | |
491 | } | |
492 | break; | |
493 | case BPF_S_ANC_RXHASH: | |
494 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4); | |
495 | if (is_imm8(offsetof(struct sk_buff, rxhash))) { | |
496 | /* mov off8(%rdi),%eax */ | |
497 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash)); | |
498 | } else { | |
499 | EMIT2(0x8b, 0x87); | |
500 | EMIT(offsetof(struct sk_buff, rxhash), 4); | |
501 | } | |
502 | break; | |
503 | case BPF_S_ANC_QUEUE: | |
504 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); | |
505 | if (is_imm8(offsetof(struct sk_buff, queue_mapping))) { | |
506 | /* movzwl off8(%rdi),%eax */ | |
507 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping)); | |
508 | } else { | |
509 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
510 | EMIT(offsetof(struct sk_buff, queue_mapping), 4); | |
511 | } | |
512 | break; | |
513 | case BPF_S_ANC_CPU: | |
514 | #ifdef CONFIG_SMP | |
515 | EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */ | |
516 | EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */ | |
517 | #else | |
518 | CLEAR_A(); | |
519 | #endif | |
520 | break; | |
855ddb56 ED |
521 | case BPF_S_ANC_VLAN_TAG: |
522 | case BPF_S_ANC_VLAN_TAG_PRESENT: | |
523 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); | |
524 | if (is_imm8(offsetof(struct sk_buff, vlan_tci))) { | |
525 | /* movzwl off8(%rdi),%eax */ | |
526 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci)); | |
527 | } else { | |
528 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
529 | EMIT(offsetof(struct sk_buff, vlan_tci), 4); | |
530 | } | |
531 | BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); | |
532 | if (filter[i].code == BPF_S_ANC_VLAN_TAG) { | |
533 | EMIT3(0x80, 0xe4, 0xef); /* and $0xef,%ah */ | |
534 | } else { | |
535 | EMIT3(0xc1, 0xe8, 0x0c); /* shr $0xc,%eax */ | |
536 | EMIT3(0x83, 0xe0, 0x01); /* and $0x1,%eax */ | |
537 | } | |
538 | break; | |
0a14842f | 539 | case BPF_S_LD_W_ABS: |
a998d434 | 540 | func = CHOOSE_LOAD_FUNC(K, sk_load_word); |
0a14842f | 541 | common_load: seen |= SEEN_DATAREF; |
0a14842f ED |
542 | t_offset = func - (image + addrs[i]); |
543 | EMIT1_off32(0xbe, K); /* mov imm32,%esi */ | |
544 | EMIT1_off32(0xe8, t_offset); /* call */ | |
545 | break; | |
546 | case BPF_S_LD_H_ABS: | |
a998d434 | 547 | func = CHOOSE_LOAD_FUNC(K, sk_load_half); |
0a14842f ED |
548 | goto common_load; |
549 | case BPF_S_LD_B_ABS: | |
a998d434 | 550 | func = CHOOSE_LOAD_FUNC(K, sk_load_byte); |
0a14842f ED |
551 | goto common_load; |
552 | case BPF_S_LDX_B_MSH: | |
a998d434 | 553 | func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh); |
0a14842f | 554 | seen |= SEEN_DATAREF | SEEN_XREG; |
a998d434 | 555 | t_offset = func - (image + addrs[i]); |
0a14842f ED |
556 | EMIT1_off32(0xbe, K); /* mov imm32,%esi */ |
557 | EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */ | |
558 | break; | |
559 | case BPF_S_LD_W_IND: | |
a998d434 | 560 | func = sk_load_word; |
0a14842f ED |
561 | common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG; |
562 | t_offset = func - (image + addrs[i]); | |
a998d434 JS |
563 | if (K) { |
564 | if (is_imm8(K)) { | |
565 | EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */ | |
566 | } else { | |
567 | EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */ | |
568 | EMIT(K, 4); | |
569 | } | |
570 | } else { | |
571 | EMIT2(0x89,0xde); /* mov %ebx,%esi */ | |
572 | } | |
0a14842f ED |
573 | EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */ |
574 | break; | |
575 | case BPF_S_LD_H_IND: | |
a998d434 | 576 | func = sk_load_half; |
0a14842f ED |
577 | goto common_load_ind; |
578 | case BPF_S_LD_B_IND: | |
a998d434 | 579 | func = sk_load_byte; |
0a14842f ED |
580 | goto common_load_ind; |
581 | case BPF_S_JMP_JA: | |
582 | t_offset = addrs[i + K] - addrs[i]; | |
583 | EMIT_JMP(t_offset); | |
584 | break; | |
585 | COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE); | |
586 | COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB); | |
587 | COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE); | |
588 | COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE); | |
589 | COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE); | |
590 | COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB); | |
591 | COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE); | |
592 | COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE); | |
593 | ||
594 | cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i]; | |
595 | t_offset = addrs[i + filter[i].jt] - addrs[i]; | |
596 | ||
597 | /* same targets, can avoid doing the test :) */ | |
598 | if (filter[i].jt == filter[i].jf) { | |
599 | EMIT_JMP(t_offset); | |
600 | break; | |
601 | } | |
602 | ||
603 | switch (filter[i].code) { | |
604 | case BPF_S_JMP_JGT_X: | |
605 | case BPF_S_JMP_JGE_X: | |
606 | case BPF_S_JMP_JEQ_X: | |
607 | seen |= SEEN_XREG; | |
608 | EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */ | |
609 | break; | |
610 | case BPF_S_JMP_JSET_X: | |
611 | seen |= SEEN_XREG; | |
612 | EMIT2(0x85, 0xd8); /* test %ebx,%eax */ | |
613 | break; | |
614 | case BPF_S_JMP_JEQ_K: | |
615 | if (K == 0) { | |
616 | EMIT2(0x85, 0xc0); /* test %eax,%eax */ | |
617 | break; | |
618 | } | |
619 | case BPF_S_JMP_JGT_K: | |
620 | case BPF_S_JMP_JGE_K: | |
621 | if (K <= 127) | |
622 | EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */ | |
623 | else | |
624 | EMIT1_off32(0x3d, K); /* cmp imm32,%eax */ | |
625 | break; | |
626 | case BPF_S_JMP_JSET_K: | |
627 | if (K <= 0xFF) | |
628 | EMIT2(0xa8, K); /* test imm8,%al */ | |
629 | else if (!(K & 0xFFFF00FF)) | |
630 | EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */ | |
631 | else if (K <= 0xFFFF) { | |
632 | EMIT2(0x66, 0xa9); /* test imm16,%ax */ | |
633 | EMIT(K, 2); | |
634 | } else { | |
635 | EMIT1_off32(0xa9, K); /* test imm32,%eax */ | |
636 | } | |
637 | break; | |
638 | } | |
639 | if (filter[i].jt != 0) { | |
a03ffcf8 MK |
640 | if (filter[i].jf && f_offset) |
641 | t_offset += is_near(f_offset) ? 2 : 5; | |
0a14842f ED |
642 | EMIT_COND_JMP(t_op, t_offset); |
643 | if (filter[i].jf) | |
644 | EMIT_JMP(f_offset); | |
645 | break; | |
646 | } | |
647 | EMIT_COND_JMP(f_op, f_offset); | |
648 | break; | |
649 | default: | |
650 | /* hmm, too complex filter, give up with jit compiler */ | |
651 | goto out; | |
652 | } | |
653 | ilen = prog - temp; | |
654 | if (image) { | |
655 | if (unlikely(proglen + ilen > oldproglen)) { | |
656 | pr_err("bpb_jit_compile fatal error\n"); | |
657 | kfree(addrs); | |
658 | module_free(NULL, image); | |
659 | return; | |
660 | } | |
661 | memcpy(image + proglen, temp, ilen); | |
662 | } | |
663 | proglen += ilen; | |
664 | addrs[i] = proglen; | |
665 | prog = temp; | |
666 | } | |
667 | /* last bpf instruction is always a RET : | |
668 | * use it to give the cleanup instruction(s) addr | |
669 | */ | |
670 | cleanup_addr = proglen - 1; /* ret */ | |
d00a9dd2 | 671 | if (seen_or_pass0) |
0a14842f | 672 | cleanup_addr -= 1; /* leaveq */ |
d00a9dd2 | 673 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
674 | cleanup_addr -= 4; /* mov -8(%rbp),%rbx */ |
675 | ||
676 | if (image) { | |
d00a9dd2 ED |
677 | if (proglen != oldproglen) |
678 | pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen); | |
0a14842f ED |
679 | break; |
680 | } | |
681 | if (proglen == oldproglen) { | |
682 | image = module_alloc(max_t(unsigned int, | |
683 | proglen, | |
684 | sizeof(struct work_struct))); | |
685 | if (!image) | |
686 | goto out; | |
687 | } | |
688 | oldproglen = proglen; | |
689 | } | |
690 | if (bpf_jit_enable > 1) | |
691 | pr_err("flen=%d proglen=%u pass=%d image=%p\n", | |
692 | flen, proglen, pass, image); | |
693 | ||
694 | if (image) { | |
695 | if (bpf_jit_enable > 1) | |
696 | print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS, | |
697 | 16, 1, image, proglen, false); | |
698 | ||
699 | bpf_flush_icache(image, image + proglen); | |
700 | ||
701 | fp->bpf_func = (void *)image; | |
702 | } | |
703 | out: | |
704 | kfree(addrs); | |
705 | return; | |
706 | } | |
707 | ||
708 | static void jit_free_defer(struct work_struct *arg) | |
709 | { | |
710 | module_free(NULL, arg); | |
711 | } | |
712 | ||
713 | /* run from softirq, we must use a work_struct to call | |
714 | * module_free() from process context | |
715 | */ | |
716 | void bpf_jit_free(struct sk_filter *fp) | |
717 | { | |
718 | if (fp->bpf_func != sk_run_filter) { | |
719 | struct work_struct *work = (struct work_struct *)fp->bpf_func; | |
720 | ||
721 | INIT_WORK(work, jit_free_defer); | |
722 | schedule_work(work); | |
723 | } | |
724 | } |