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0a14842f ED |
1 | /* bpf_jit_comp.c : BPF JIT compiler |
2 | * | |
3b58908a | 3 | * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com) |
0a14842f ED |
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> |
314beb9b | 15 | #include <linux/random.h> |
0a14842f ED |
16 | |
17 | /* | |
18 | * Conventions : | |
19 | * EAX : BPF A accumulator | |
20 | * EBX : BPF X accumulator | |
21 | * RDI : pointer to skb (first argument given to JIT function) | |
22 | * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n) | |
23 | * ECX,EDX,ESI : scratch registers | |
24 | * r9d : skb->len - skb->data_len (headlen) | |
25 | * r8 : skb->data | |
26 | * -8(RBP) : saved RBX value | |
27 | * -16(RBP)..-80(RBP) : BPF_MEMWORDS values | |
28 | */ | |
29 | int bpf_jit_enable __read_mostly; | |
30 | ||
31 | /* | |
32 | * assembly code in arch/x86/net/bpf_jit.S | |
33 | */ | |
34 | extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[]; | |
a998d434 JS |
35 | extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[]; |
36 | extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[]; | |
37 | extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[]; | |
38 | extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[]; | |
0a14842f ED |
39 | |
40 | static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) | |
41 | { | |
42 | if (len == 1) | |
43 | *ptr = bytes; | |
44 | else if (len == 2) | |
45 | *(u16 *)ptr = bytes; | |
46 | else { | |
47 | *(u32 *)ptr = bytes; | |
48 | barrier(); | |
49 | } | |
50 | return ptr + len; | |
51 | } | |
52 | ||
53 | #define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0) | |
54 | ||
55 | #define EMIT1(b1) EMIT(b1, 1) | |
56 | #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2) | |
57 | #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3) | |
58 | #define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4) | |
59 | #define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0) | |
60 | ||
61 | #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */ | |
62 | #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */ | |
63 | ||
64 | static inline bool is_imm8(int value) | |
65 | { | |
66 | return value <= 127 && value >= -128; | |
67 | } | |
68 | ||
69 | static inline bool is_near(int offset) | |
70 | { | |
71 | return offset <= 127 && offset >= -128; | |
72 | } | |
73 | ||
74 | #define EMIT_JMP(offset) \ | |
75 | do { \ | |
76 | if (offset) { \ | |
77 | if (is_near(offset)) \ | |
78 | EMIT2(0xeb, offset); /* jmp .+off8 */ \ | |
79 | else \ | |
80 | EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \ | |
81 | } \ | |
82 | } while (0) | |
83 | ||
84 | /* list of x86 cond jumps opcodes (. + s8) | |
85 | * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32) | |
86 | */ | |
87 | #define X86_JB 0x72 | |
88 | #define X86_JAE 0x73 | |
89 | #define X86_JE 0x74 | |
90 | #define X86_JNE 0x75 | |
91 | #define X86_JBE 0x76 | |
92 | #define X86_JA 0x77 | |
93 | ||
94 | #define EMIT_COND_JMP(op, offset) \ | |
95 | do { \ | |
96 | if (is_near(offset)) \ | |
97 | EMIT2(op, offset); /* jxx .+off8 */ \ | |
98 | else { \ | |
99 | EMIT2(0x0f, op + 0x10); \ | |
100 | EMIT(offset, 4); /* jxx .+off32 */ \ | |
101 | } \ | |
102 | } while (0) | |
103 | ||
104 | #define COND_SEL(CODE, TOP, FOP) \ | |
105 | case CODE: \ | |
106 | t_op = TOP; \ | |
107 | f_op = FOP; \ | |
108 | goto cond_branch | |
109 | ||
110 | ||
111 | #define SEEN_DATAREF 1 /* might call external helpers */ | |
112 | #define SEEN_XREG 2 /* ebx is used */ | |
113 | #define SEEN_MEM 4 /* use mem[] for temporary storage */ | |
114 | ||
115 | static inline void bpf_flush_icache(void *start, void *end) | |
116 | { | |
117 | mm_segment_t old_fs = get_fs(); | |
118 | ||
119 | set_fs(KERNEL_DS); | |
120 | smp_wmb(); | |
121 | flush_icache_range((unsigned long)start, (unsigned long)end); | |
122 | set_fs(old_fs); | |
123 | } | |
124 | ||
a998d434 JS |
125 | #define CHOOSE_LOAD_FUNC(K, func) \ |
126 | ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset) | |
0a14842f | 127 | |
3b58908a ED |
128 | /* Helper to find the offset of pkt_type in sk_buff |
129 | * We want to make sure its still a 3bit field starting at a byte boundary. | |
130 | */ | |
131 | #define PKT_TYPE_MAX 7 | |
132 | static int pkt_type_offset(void) | |
133 | { | |
134 | struct sk_buff skb_probe = { | |
135 | .pkt_type = ~0, | |
136 | }; | |
137 | char *ct = (char *)&skb_probe; | |
138 | unsigned int off; | |
139 | ||
140 | for (off = 0; off < sizeof(struct sk_buff); off++) { | |
141 | if (ct[off] == PKT_TYPE_MAX) | |
142 | return off; | |
143 | } | |
144 | pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n"); | |
145 | return -1; | |
146 | } | |
147 | ||
314beb9b ED |
148 | struct bpf_binary_header { |
149 | unsigned int pages; | |
150 | /* Note : for security reasons, bpf code will follow a randomly | |
151 | * sized amount of int3 instructions | |
152 | */ | |
153 | u8 image[]; | |
154 | }; | |
155 | ||
156 | static struct bpf_binary_header *bpf_alloc_binary(unsigned int proglen, | |
157 | u8 **image_ptr) | |
158 | { | |
159 | unsigned int sz, hole; | |
160 | struct bpf_binary_header *header; | |
161 | ||
162 | /* Most of BPF filters are really small, | |
163 | * but if some of them fill a page, allow at least | |
164 | * 128 extra bytes to insert a random section of int3 | |
165 | */ | |
166 | sz = round_up(proglen + sizeof(*header) + 128, PAGE_SIZE); | |
167 | header = module_alloc(sz); | |
168 | if (!header) | |
169 | return NULL; | |
170 | ||
171 | memset(header, 0xcc, sz); /* fill whole space with int3 instructions */ | |
172 | ||
173 | header->pages = sz / PAGE_SIZE; | |
174 | hole = sz - (proglen + sizeof(*header)); | |
175 | ||
176 | /* insert a random number of int3 instructions before BPF code */ | |
177 | *image_ptr = &header->image[prandom_u32() % hole]; | |
178 | return header; | |
179 | } | |
180 | ||
0a14842f ED |
181 | void bpf_jit_compile(struct sk_filter *fp) |
182 | { | |
183 | u8 temp[64]; | |
184 | u8 *prog; | |
185 | unsigned int proglen, oldproglen = 0; | |
186 | int ilen, i; | |
187 | int t_offset, f_offset; | |
188 | u8 t_op, f_op, seen = 0, pass; | |
189 | u8 *image = NULL; | |
314beb9b | 190 | struct bpf_binary_header *header = NULL; |
0a14842f ED |
191 | u8 *func; |
192 | int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */ | |
193 | unsigned int cleanup_addr; /* epilogue code offset */ | |
194 | unsigned int *addrs; | |
195 | const struct sock_filter *filter = fp->insns; | |
196 | int flen = fp->len; | |
197 | ||
198 | if (!bpf_jit_enable) | |
199 | return; | |
200 | ||
201 | addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL); | |
202 | if (addrs == NULL) | |
203 | return; | |
204 | ||
205 | /* Before first pass, make a rough estimation of addrs[] | |
206 | * each bpf instruction is translated to less than 64 bytes | |
207 | */ | |
208 | for (proglen = 0, i = 0; i < flen; i++) { | |
209 | proglen += 64; | |
210 | addrs[i] = proglen; | |
211 | } | |
212 | cleanup_addr = proglen; /* epilogue address */ | |
213 | ||
214 | for (pass = 0; pass < 10; pass++) { | |
d00a9dd2 | 215 | u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen; |
0a14842f ED |
216 | /* no prologue/epilogue for trivial filters (RET something) */ |
217 | proglen = 0; | |
218 | prog = temp; | |
219 | ||
d00a9dd2 | 220 | if (seen_or_pass0) { |
0a14842f ED |
221 | EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */ |
222 | EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */ | |
223 | /* note : must save %rbx in case bpf_error is hit */ | |
d00a9dd2 | 224 | if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF)) |
0a14842f | 225 | EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */ |
d00a9dd2 | 226 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
227 | CLEAR_X(); /* make sure we dont leek kernel memory */ |
228 | ||
229 | /* | |
230 | * If this filter needs to access skb data, | |
231 | * loads r9 and r8 with : | |
232 | * r9 = skb->len - skb->data_len | |
233 | * r8 = skb->data | |
234 | */ | |
d00a9dd2 | 235 | if (seen_or_pass0 & SEEN_DATAREF) { |
0a14842f ED |
236 | if (offsetof(struct sk_buff, len) <= 127) |
237 | /* mov off8(%rdi),%r9d */ | |
238 | EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len)); | |
239 | else { | |
240 | /* mov off32(%rdi),%r9d */ | |
241 | EMIT3(0x44, 0x8b, 0x8f); | |
242 | EMIT(offsetof(struct sk_buff, len), 4); | |
243 | } | |
244 | if (is_imm8(offsetof(struct sk_buff, data_len))) | |
245 | /* sub off8(%rdi),%r9d */ | |
246 | EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len)); | |
247 | else { | |
248 | EMIT3(0x44, 0x2b, 0x8f); | |
249 | EMIT(offsetof(struct sk_buff, data_len), 4); | |
250 | } | |
251 | ||
252 | if (is_imm8(offsetof(struct sk_buff, data))) | |
253 | /* mov off8(%rdi),%r8 */ | |
254 | EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data)); | |
255 | else { | |
256 | /* mov off32(%rdi),%r8 */ | |
257 | EMIT3(0x4c, 0x8b, 0x87); | |
258 | EMIT(offsetof(struct sk_buff, data), 4); | |
259 | } | |
260 | } | |
261 | } | |
262 | ||
263 | switch (filter[0].code) { | |
264 | case BPF_S_RET_K: | |
265 | case BPF_S_LD_W_LEN: | |
266 | case BPF_S_ANC_PROTOCOL: | |
267 | case BPF_S_ANC_IFINDEX: | |
268 | case BPF_S_ANC_MARK: | |
269 | case BPF_S_ANC_RXHASH: | |
270 | case BPF_S_ANC_CPU: | |
855ddb56 ED |
271 | case BPF_S_ANC_VLAN_TAG: |
272 | case BPF_S_ANC_VLAN_TAG_PRESENT: | |
0a14842f | 273 | case BPF_S_ANC_QUEUE: |
3b58908a | 274 | case BPF_S_ANC_PKTTYPE: |
0a14842f ED |
275 | case BPF_S_LD_W_ABS: |
276 | case BPF_S_LD_H_ABS: | |
277 | case BPF_S_LD_B_ABS: | |
278 | /* first instruction sets A register (or is RET 'constant') */ | |
279 | break; | |
280 | default: | |
281 | /* make sure we dont leak kernel information to user */ | |
282 | CLEAR_A(); /* A = 0 */ | |
283 | } | |
284 | ||
285 | for (i = 0; i < flen; i++) { | |
286 | unsigned int K = filter[i].k; | |
287 | ||
288 | switch (filter[i].code) { | |
289 | case BPF_S_ALU_ADD_X: /* A += X; */ | |
290 | seen |= SEEN_XREG; | |
291 | EMIT2(0x01, 0xd8); /* add %ebx,%eax */ | |
292 | break; | |
293 | case BPF_S_ALU_ADD_K: /* A += K; */ | |
294 | if (!K) | |
295 | break; | |
296 | if (is_imm8(K)) | |
297 | EMIT3(0x83, 0xc0, K); /* add imm8,%eax */ | |
298 | else | |
299 | EMIT1_off32(0x05, K); /* add imm32,%eax */ | |
300 | break; | |
301 | case BPF_S_ALU_SUB_X: /* A -= X; */ | |
302 | seen |= SEEN_XREG; | |
303 | EMIT2(0x29, 0xd8); /* sub %ebx,%eax */ | |
304 | break; | |
305 | case BPF_S_ALU_SUB_K: /* A -= K */ | |
306 | if (!K) | |
307 | break; | |
308 | if (is_imm8(K)) | |
309 | EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */ | |
310 | else | |
311 | EMIT1_off32(0x2d, K); /* sub imm32,%eax */ | |
312 | break; | |
313 | case BPF_S_ALU_MUL_X: /* A *= X; */ | |
314 | seen |= SEEN_XREG; | |
315 | EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */ | |
316 | break; | |
317 | case BPF_S_ALU_MUL_K: /* A *= K */ | |
318 | if (is_imm8(K)) | |
319 | EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */ | |
320 | else { | |
321 | EMIT2(0x69, 0xc0); /* imul imm32,%eax */ | |
322 | EMIT(K, 4); | |
323 | } | |
324 | break; | |
325 | case BPF_S_ALU_DIV_X: /* A /= X; */ | |
326 | seen |= SEEN_XREG; | |
327 | EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ | |
d00a9dd2 ED |
328 | if (pc_ret0 > 0) { |
329 | /* addrs[pc_ret0 - 1] is start address of target | |
330 | * (addrs[i] - 4) is the address following this jmp | |
331 | * ("xor %edx,%edx; div %ebx" being 4 bytes long) | |
332 | */ | |
333 | EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] - | |
334 | (addrs[i] - 4)); | |
335 | } else { | |
0a14842f ED |
336 | EMIT_COND_JMP(X86_JNE, 2 + 5); |
337 | CLEAR_A(); | |
338 | EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */ | |
339 | } | |
340 | EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */ | |
341 | break; | |
280050cc ED |
342 | case BPF_S_ALU_MOD_X: /* A %= X; */ |
343 | seen |= SEEN_XREG; | |
344 | EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ | |
345 | if (pc_ret0 > 0) { | |
346 | /* addrs[pc_ret0 - 1] is start address of target | |
347 | * (addrs[i] - 6) is the address following this jmp | |
348 | * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long) | |
349 | */ | |
350 | EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] - | |
351 | (addrs[i] - 6)); | |
352 | } else { | |
353 | EMIT_COND_JMP(X86_JNE, 2 + 5); | |
354 | CLEAR_A(); | |
355 | EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */ | |
356 | } | |
357 | EMIT2(0x31, 0xd2); /* xor %edx,%edx */ | |
358 | EMIT2(0xf7, 0xf3); /* div %ebx */ | |
359 | EMIT2(0x89, 0xd0); /* mov %edx,%eax */ | |
360 | break; | |
361 | case BPF_S_ALU_MOD_K: /* A %= K; */ | |
aee636c4 ED |
362 | if (K == 1) { |
363 | CLEAR_A(); | |
364 | break; | |
365 | } | |
280050cc ED |
366 | EMIT2(0x31, 0xd2); /* xor %edx,%edx */ |
367 | EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */ | |
368 | EMIT2(0xf7, 0xf1); /* div %ecx */ | |
369 | EMIT2(0x89, 0xd0); /* mov %edx,%eax */ | |
370 | break; | |
aee636c4 ED |
371 | case BPF_S_ALU_DIV_K: /* A /= K */ |
372 | if (K == 1) | |
373 | break; | |
374 | EMIT2(0x31, 0xd2); /* xor %edx,%edx */ | |
375 | EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */ | |
376 | EMIT2(0xf7, 0xf1); /* div %ecx */ | |
0a14842f ED |
377 | break; |
378 | case BPF_S_ALU_AND_X: | |
379 | seen |= SEEN_XREG; | |
380 | EMIT2(0x21, 0xd8); /* and %ebx,%eax */ | |
381 | break; | |
382 | case BPF_S_ALU_AND_K: | |
383 | if (K >= 0xFFFFFF00) { | |
384 | EMIT2(0x24, K & 0xFF); /* and imm8,%al */ | |
385 | } else if (K >= 0xFFFF0000) { | |
386 | EMIT2(0x66, 0x25); /* and imm16,%ax */ | |
1d24fb36 | 387 | EMIT(K, 2); |
0a14842f ED |
388 | } else { |
389 | EMIT1_off32(0x25, K); /* and imm32,%eax */ | |
390 | } | |
391 | break; | |
392 | case BPF_S_ALU_OR_X: | |
393 | seen |= SEEN_XREG; | |
394 | EMIT2(0x09, 0xd8); /* or %ebx,%eax */ | |
395 | break; | |
396 | case BPF_S_ALU_OR_K: | |
397 | if (is_imm8(K)) | |
398 | EMIT3(0x83, 0xc8, K); /* or imm8,%eax */ | |
399 | else | |
400 | EMIT1_off32(0x0d, K); /* or imm32,%eax */ | |
4bfaddf1 ED |
401 | break; |
402 | case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */ | |
82c93fcc | 403 | case BPF_S_ALU_XOR_X: |
4bfaddf1 ED |
404 | seen |= SEEN_XREG; |
405 | EMIT2(0x31, 0xd8); /* xor %ebx,%eax */ | |
82c93fcc DB |
406 | break; |
407 | case BPF_S_ALU_XOR_K: /* A ^= K; */ | |
408 | if (K == 0) | |
409 | break; | |
410 | if (is_imm8(K)) | |
411 | EMIT3(0x83, 0xf0, K); /* xor imm8,%eax */ | |
412 | else | |
413 | EMIT1_off32(0x35, K); /* xor imm32,%eax */ | |
0a14842f ED |
414 | break; |
415 | case BPF_S_ALU_LSH_X: /* A <<= X; */ | |
416 | seen |= SEEN_XREG; | |
417 | EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */ | |
418 | break; | |
419 | case BPF_S_ALU_LSH_K: | |
420 | if (K == 0) | |
421 | break; | |
422 | else if (K == 1) | |
423 | EMIT2(0xd1, 0xe0); /* shl %eax */ | |
424 | else | |
425 | EMIT3(0xc1, 0xe0, K); | |
426 | break; | |
427 | case BPF_S_ALU_RSH_X: /* A >>= X; */ | |
428 | seen |= SEEN_XREG; | |
429 | EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */ | |
430 | break; | |
431 | case BPF_S_ALU_RSH_K: /* A >>= K; */ | |
432 | if (K == 0) | |
433 | break; | |
434 | else if (K == 1) | |
435 | EMIT2(0xd1, 0xe8); /* shr %eax */ | |
436 | else | |
437 | EMIT3(0xc1, 0xe8, K); | |
438 | break; | |
439 | case BPF_S_ALU_NEG: | |
440 | EMIT2(0xf7, 0xd8); /* neg %eax */ | |
441 | break; | |
442 | case BPF_S_RET_K: | |
443 | if (!K) { | |
444 | if (pc_ret0 == -1) | |
445 | pc_ret0 = i; | |
446 | CLEAR_A(); | |
447 | } else { | |
448 | EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ | |
449 | } | |
450 | /* fallinto */ | |
451 | case BPF_S_RET_A: | |
d00a9dd2 | 452 | if (seen_or_pass0) { |
0a14842f ED |
453 | if (i != flen - 1) { |
454 | EMIT_JMP(cleanup_addr - addrs[i]); | |
455 | break; | |
456 | } | |
d00a9dd2 | 457 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
458 | EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */ |
459 | EMIT1(0xc9); /* leaveq */ | |
460 | } | |
461 | EMIT1(0xc3); /* ret */ | |
462 | break; | |
463 | case BPF_S_MISC_TAX: /* X = A */ | |
464 | seen |= SEEN_XREG; | |
465 | EMIT2(0x89, 0xc3); /* mov %eax,%ebx */ | |
466 | break; | |
467 | case BPF_S_MISC_TXA: /* A = X */ | |
468 | seen |= SEEN_XREG; | |
469 | EMIT2(0x89, 0xd8); /* mov %ebx,%eax */ | |
470 | break; | |
471 | case BPF_S_LD_IMM: /* A = K */ | |
472 | if (!K) | |
473 | CLEAR_A(); | |
474 | else | |
475 | EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ | |
476 | break; | |
477 | case BPF_S_LDX_IMM: /* X = K */ | |
478 | seen |= SEEN_XREG; | |
479 | if (!K) | |
480 | CLEAR_X(); | |
481 | else | |
482 | EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */ | |
483 | break; | |
484 | case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */ | |
485 | seen |= SEEN_MEM; | |
486 | EMIT3(0x8b, 0x45, 0xf0 - K*4); | |
487 | break; | |
488 | case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */ | |
489 | seen |= SEEN_XREG | SEEN_MEM; | |
490 | EMIT3(0x8b, 0x5d, 0xf0 - K*4); | |
491 | break; | |
492 | case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */ | |
493 | seen |= SEEN_MEM; | |
494 | EMIT3(0x89, 0x45, 0xf0 - K*4); | |
495 | break; | |
496 | case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */ | |
497 | seen |= SEEN_XREG | SEEN_MEM; | |
498 | EMIT3(0x89, 0x5d, 0xf0 - K*4); | |
499 | break; | |
500 | case BPF_S_LD_W_LEN: /* A = skb->len; */ | |
501 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); | |
502 | if (is_imm8(offsetof(struct sk_buff, len))) | |
503 | /* mov off8(%rdi),%eax */ | |
504 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len)); | |
505 | else { | |
506 | EMIT2(0x8b, 0x87); | |
507 | EMIT(offsetof(struct sk_buff, len), 4); | |
508 | } | |
509 | break; | |
510 | case BPF_S_LDX_W_LEN: /* X = skb->len; */ | |
511 | seen |= SEEN_XREG; | |
512 | if (is_imm8(offsetof(struct sk_buff, len))) | |
513 | /* mov off8(%rdi),%ebx */ | |
514 | EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len)); | |
515 | else { | |
516 | EMIT2(0x8b, 0x9f); | |
517 | EMIT(offsetof(struct sk_buff, len), 4); | |
518 | } | |
519 | break; | |
520 | case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */ | |
521 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); | |
522 | if (is_imm8(offsetof(struct sk_buff, protocol))) { | |
523 | /* movzwl off8(%rdi),%eax */ | |
524 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol)); | |
525 | } else { | |
526 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
527 | EMIT(offsetof(struct sk_buff, protocol), 4); | |
528 | } | |
529 | EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */ | |
530 | break; | |
531 | case BPF_S_ANC_IFINDEX: | |
532 | if (is_imm8(offsetof(struct sk_buff, dev))) { | |
533 | /* movq off8(%rdi),%rax */ | |
534 | EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev)); | |
535 | } else { | |
536 | EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */ | |
537 | EMIT(offsetof(struct sk_buff, dev), 4); | |
538 | } | |
539 | EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */ | |
540 | EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6)); | |
541 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); | |
542 | EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */ | |
543 | EMIT(offsetof(struct net_device, ifindex), 4); | |
544 | break; | |
545 | case BPF_S_ANC_MARK: | |
546 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); | |
547 | if (is_imm8(offsetof(struct sk_buff, mark))) { | |
548 | /* mov off8(%rdi),%eax */ | |
549 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark)); | |
550 | } else { | |
551 | EMIT2(0x8b, 0x87); | |
552 | EMIT(offsetof(struct sk_buff, mark), 4); | |
553 | } | |
554 | break; | |
555 | case BPF_S_ANC_RXHASH: | |
61b905da TH |
556 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); |
557 | if (is_imm8(offsetof(struct sk_buff, hash))) { | |
0a14842f | 558 | /* mov off8(%rdi),%eax */ |
61b905da | 559 | EMIT3(0x8b, 0x47, offsetof(struct sk_buff, hash)); |
0a14842f ED |
560 | } else { |
561 | EMIT2(0x8b, 0x87); | |
61b905da | 562 | EMIT(offsetof(struct sk_buff, hash), 4); |
0a14842f ED |
563 | } |
564 | break; | |
565 | case BPF_S_ANC_QUEUE: | |
566 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); | |
567 | if (is_imm8(offsetof(struct sk_buff, queue_mapping))) { | |
568 | /* movzwl off8(%rdi),%eax */ | |
569 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping)); | |
570 | } else { | |
571 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
572 | EMIT(offsetof(struct sk_buff, queue_mapping), 4); | |
573 | } | |
574 | break; | |
575 | case BPF_S_ANC_CPU: | |
576 | #ifdef CONFIG_SMP | |
577 | EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */ | |
578 | EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */ | |
579 | #else | |
580 | CLEAR_A(); | |
581 | #endif | |
582 | break; | |
855ddb56 ED |
583 | case BPF_S_ANC_VLAN_TAG: |
584 | case BPF_S_ANC_VLAN_TAG_PRESENT: | |
585 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); | |
586 | if (is_imm8(offsetof(struct sk_buff, vlan_tci))) { | |
587 | /* movzwl off8(%rdi),%eax */ | |
588 | EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci)); | |
589 | } else { | |
590 | EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ | |
591 | EMIT(offsetof(struct sk_buff, vlan_tci), 4); | |
592 | } | |
593 | BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); | |
594 | if (filter[i].code == BPF_S_ANC_VLAN_TAG) { | |
595 | EMIT3(0x80, 0xe4, 0xef); /* and $0xef,%ah */ | |
596 | } else { | |
597 | EMIT3(0xc1, 0xe8, 0x0c); /* shr $0xc,%eax */ | |
598 | EMIT3(0x83, 0xe0, 0x01); /* and $0x1,%eax */ | |
599 | } | |
600 | break; | |
3b58908a ED |
601 | case BPF_S_ANC_PKTTYPE: |
602 | { | |
603 | int off = pkt_type_offset(); | |
604 | ||
605 | if (off < 0) | |
606 | goto out; | |
607 | if (is_imm8(off)) { | |
608 | /* movzbl off8(%rdi),%eax */ | |
609 | EMIT4(0x0f, 0xb6, 0x47, off); | |
610 | } else { | |
611 | /* movbl off32(%rdi),%eax */ | |
612 | EMIT3(0x0f, 0xb6, 0x87); | |
613 | EMIT(off, 4); | |
614 | } | |
615 | EMIT3(0x83, 0xe0, PKT_TYPE_MAX); /* and $0x7,%eax */ | |
616 | break; | |
617 | } | |
0a14842f | 618 | case BPF_S_LD_W_ABS: |
a998d434 | 619 | func = CHOOSE_LOAD_FUNC(K, sk_load_word); |
0a14842f | 620 | common_load: seen |= SEEN_DATAREF; |
0a14842f ED |
621 | t_offset = func - (image + addrs[i]); |
622 | EMIT1_off32(0xbe, K); /* mov imm32,%esi */ | |
623 | EMIT1_off32(0xe8, t_offset); /* call */ | |
624 | break; | |
625 | case BPF_S_LD_H_ABS: | |
a998d434 | 626 | func = CHOOSE_LOAD_FUNC(K, sk_load_half); |
0a14842f ED |
627 | goto common_load; |
628 | case BPF_S_LD_B_ABS: | |
a998d434 | 629 | func = CHOOSE_LOAD_FUNC(K, sk_load_byte); |
0a14842f ED |
630 | goto common_load; |
631 | case BPF_S_LDX_B_MSH: | |
a998d434 | 632 | func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh); |
0a14842f | 633 | seen |= SEEN_DATAREF | SEEN_XREG; |
a998d434 | 634 | t_offset = func - (image + addrs[i]); |
0a14842f ED |
635 | EMIT1_off32(0xbe, K); /* mov imm32,%esi */ |
636 | EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */ | |
637 | break; | |
638 | case BPF_S_LD_W_IND: | |
a998d434 | 639 | func = sk_load_word; |
0a14842f ED |
640 | common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG; |
641 | t_offset = func - (image + addrs[i]); | |
a998d434 JS |
642 | if (K) { |
643 | if (is_imm8(K)) { | |
644 | EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */ | |
645 | } else { | |
646 | EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */ | |
647 | EMIT(K, 4); | |
648 | } | |
649 | } else { | |
650 | EMIT2(0x89,0xde); /* mov %ebx,%esi */ | |
651 | } | |
0a14842f ED |
652 | EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */ |
653 | break; | |
654 | case BPF_S_LD_H_IND: | |
a998d434 | 655 | func = sk_load_half; |
0a14842f ED |
656 | goto common_load_ind; |
657 | case BPF_S_LD_B_IND: | |
a998d434 | 658 | func = sk_load_byte; |
0a14842f ED |
659 | goto common_load_ind; |
660 | case BPF_S_JMP_JA: | |
661 | t_offset = addrs[i + K] - addrs[i]; | |
662 | EMIT_JMP(t_offset); | |
663 | break; | |
664 | COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE); | |
665 | COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB); | |
666 | COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE); | |
667 | COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE); | |
668 | COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE); | |
669 | COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB); | |
670 | COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE); | |
671 | COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE); | |
672 | ||
673 | cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i]; | |
674 | t_offset = addrs[i + filter[i].jt] - addrs[i]; | |
675 | ||
676 | /* same targets, can avoid doing the test :) */ | |
677 | if (filter[i].jt == filter[i].jf) { | |
678 | EMIT_JMP(t_offset); | |
679 | break; | |
680 | } | |
681 | ||
682 | switch (filter[i].code) { | |
683 | case BPF_S_JMP_JGT_X: | |
684 | case BPF_S_JMP_JGE_X: | |
685 | case BPF_S_JMP_JEQ_X: | |
686 | seen |= SEEN_XREG; | |
687 | EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */ | |
688 | break; | |
689 | case BPF_S_JMP_JSET_X: | |
690 | seen |= SEEN_XREG; | |
691 | EMIT2(0x85, 0xd8); /* test %ebx,%eax */ | |
692 | break; | |
693 | case BPF_S_JMP_JEQ_K: | |
694 | if (K == 0) { | |
695 | EMIT2(0x85, 0xc0); /* test %eax,%eax */ | |
696 | break; | |
697 | } | |
698 | case BPF_S_JMP_JGT_K: | |
699 | case BPF_S_JMP_JGE_K: | |
700 | if (K <= 127) | |
701 | EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */ | |
702 | else | |
703 | EMIT1_off32(0x3d, K); /* cmp imm32,%eax */ | |
704 | break; | |
705 | case BPF_S_JMP_JSET_K: | |
706 | if (K <= 0xFF) | |
707 | EMIT2(0xa8, K); /* test imm8,%al */ | |
708 | else if (!(K & 0xFFFF00FF)) | |
709 | EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */ | |
710 | else if (K <= 0xFFFF) { | |
711 | EMIT2(0x66, 0xa9); /* test imm16,%ax */ | |
712 | EMIT(K, 2); | |
713 | } else { | |
714 | EMIT1_off32(0xa9, K); /* test imm32,%eax */ | |
715 | } | |
716 | break; | |
717 | } | |
718 | if (filter[i].jt != 0) { | |
a03ffcf8 MK |
719 | if (filter[i].jf && f_offset) |
720 | t_offset += is_near(f_offset) ? 2 : 5; | |
0a14842f ED |
721 | EMIT_COND_JMP(t_op, t_offset); |
722 | if (filter[i].jf) | |
723 | EMIT_JMP(f_offset); | |
724 | break; | |
725 | } | |
726 | EMIT_COND_JMP(f_op, f_offset); | |
727 | break; | |
728 | default: | |
729 | /* hmm, too complex filter, give up with jit compiler */ | |
730 | goto out; | |
731 | } | |
732 | ilen = prog - temp; | |
733 | if (image) { | |
734 | if (unlikely(proglen + ilen > oldproglen)) { | |
735 | pr_err("bpb_jit_compile fatal error\n"); | |
736 | kfree(addrs); | |
314beb9b | 737 | module_free(NULL, header); |
0a14842f ED |
738 | return; |
739 | } | |
740 | memcpy(image + proglen, temp, ilen); | |
741 | } | |
742 | proglen += ilen; | |
743 | addrs[i] = proglen; | |
744 | prog = temp; | |
745 | } | |
746 | /* last bpf instruction is always a RET : | |
747 | * use it to give the cleanup instruction(s) addr | |
748 | */ | |
749 | cleanup_addr = proglen - 1; /* ret */ | |
d00a9dd2 | 750 | if (seen_or_pass0) |
0a14842f | 751 | cleanup_addr -= 1; /* leaveq */ |
d00a9dd2 | 752 | if (seen_or_pass0 & SEEN_XREG) |
0a14842f ED |
753 | cleanup_addr -= 4; /* mov -8(%rbp),%rbx */ |
754 | ||
755 | if (image) { | |
d00a9dd2 ED |
756 | if (proglen != oldproglen) |
757 | pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen); | |
0a14842f ED |
758 | break; |
759 | } | |
760 | if (proglen == oldproglen) { | |
314beb9b ED |
761 | header = bpf_alloc_binary(proglen, &image); |
762 | if (!header) | |
0a14842f ED |
763 | goto out; |
764 | } | |
765 | oldproglen = proglen; | |
766 | } | |
79617801 | 767 | |
0a14842f | 768 | if (bpf_jit_enable > 1) |
79617801 | 769 | bpf_jit_dump(flen, proglen, pass, image); |
0a14842f ED |
770 | |
771 | if (image) { | |
314beb9b ED |
772 | bpf_flush_icache(header, image + proglen); |
773 | set_memory_ro((unsigned long)header, header->pages); | |
0a14842f | 774 | fp->bpf_func = (void *)image; |
f8bbbfc3 | 775 | fp->jited = 1; |
0a14842f ED |
776 | } |
777 | out: | |
778 | kfree(addrs); | |
779 | return; | |
780 | } | |
781 | ||
d45ed4a4 AS |
782 | static void bpf_jit_free_deferred(struct work_struct *work) |
783 | { | |
784 | struct sk_filter *fp = container_of(work, struct sk_filter, work); | |
785 | unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK; | |
786 | struct bpf_binary_header *header = (void *)addr; | |
787 | ||
788 | set_memory_rw(addr, header->pages); | |
789 | module_free(NULL, header); | |
790 | kfree(fp); | |
791 | } | |
792 | ||
0a14842f ED |
793 | void bpf_jit_free(struct sk_filter *fp) |
794 | { | |
f8bbbfc3 | 795 | if (fp->jited) { |
d45ed4a4 AS |
796 | INIT_WORK(&fp->work, bpf_jit_free_deferred); |
797 | schedule_work(&fp->work); | |
98bbc06a AV |
798 | } else { |
799 | kfree(fp); | |
314beb9b | 800 | } |
0a14842f | 801 | } |