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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>
14
15/*
16 * Conventions :
17 * EAX : BPF A accumulator
18 * EBX : BPF X accumulator
19 * RDI : pointer to skb (first argument given to JIT function)
20 * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
21 * ECX,EDX,ESI : scratch registers
22 * r9d : skb->len - skb->data_len (headlen)
23 * r8 : skb->data
24 * -8(RBP) : saved RBX value
25 * -16(RBP)..-80(RBP) : BPF_MEMWORDS values
26 */
27int bpf_jit_enable __read_mostly;
28
29/*
30 * assembly code in arch/x86/net/bpf_jit.S
31 */
32extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
33extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
34extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[];
35extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
36extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[];
37
38static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
39{
40 if (len == 1)
41 *ptr = bytes;
42 else if (len == 2)
43 *(u16 *)ptr = bytes;
44 else {
45 *(u32 *)ptr = bytes;
46 barrier();
47 }
48 return ptr + len;
49}
50
51#define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0)
52
53#define EMIT1(b1) EMIT(b1, 1)
54#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
55#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
56#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
57#define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0)
58
59#define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
60#define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
61
62static inline bool is_imm8(int value)
63{
64 return value <= 127 && value >= -128;
65}
66
67static inline bool is_near(int offset)
68{
69 return offset <= 127 && offset >= -128;
70}
71
72#define EMIT_JMP(offset) \
73do { \
74 if (offset) { \
75 if (is_near(offset)) \
76 EMIT2(0xeb, offset); /* jmp .+off8 */ \
77 else \
78 EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \
79 } \
80} while (0)
81
82/* list of x86 cond jumps opcodes (. + s8)
83 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
84 */
85#define X86_JB 0x72
86#define X86_JAE 0x73
87#define X86_JE 0x74
88#define X86_JNE 0x75
89#define X86_JBE 0x76
90#define X86_JA 0x77
91
92#define EMIT_COND_JMP(op, offset) \
93do { \
94 if (is_near(offset)) \
95 EMIT2(op, offset); /* jxx .+off8 */ \
96 else { \
97 EMIT2(0x0f, op + 0x10); \
98 EMIT(offset, 4); /* jxx .+off32 */ \
99 } \
100} while (0)
101
102#define COND_SEL(CODE, TOP, FOP) \
103 case CODE: \
104 t_op = TOP; \
105 f_op = FOP; \
106 goto cond_branch
107
108
109#define SEEN_DATAREF 1 /* might call external helpers */
110#define SEEN_XREG 2 /* ebx is used */
111#define SEEN_MEM 4 /* use mem[] for temporary storage */
112
113static inline void bpf_flush_icache(void *start, void *end)
114{
115 mm_segment_t old_fs = get_fs();
116
117 set_fs(KERNEL_DS);
118 smp_wmb();
119 flush_icache_range((unsigned long)start, (unsigned long)end);
120 set_fs(old_fs);
121}
122
123#define CHOOSE_LOAD_FUNC(K, func) \
124 ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
125
126void bpf_jit_compile(struct sk_filter *fp)
127{
128 u8 temp[64];
129 u8 *prog;
130 unsigned int proglen, oldproglen = 0;
131 int ilen, i;
132 int t_offset, f_offset;
133 u8 t_op, f_op, seen = 0, pass;
134 u8 *image = NULL;
135 u8 *func;
136 int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
137 unsigned int cleanup_addr; /* epilogue code offset */
138 unsigned int *addrs;
139 const struct sock_filter *filter = fp->insns;
140 int flen = fp->len;
141
142 if (!bpf_jit_enable)
143 return;
144
145 addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
146 if (addrs == NULL)
147 return;
148
149 /* Before first pass, make a rough estimation of addrs[]
150 * each bpf instruction is translated to less than 64 bytes
151 */
152 for (proglen = 0, i = 0; i < flen; i++) {
153 proglen += 64;
154 addrs[i] = proglen;
155 }
156 cleanup_addr = proglen; /* epilogue address */
157
158 for (pass = 0; pass < 10; pass++) {
159 u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
160 /* no prologue/epilogue for trivial filters (RET something) */
161 proglen = 0;
162 prog = temp;
163
164 if (seen_or_pass0) {
165 EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
166 EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */
167 /* note : must save %rbx in case bpf_error is hit */
168 if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
169 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
170 if (seen_or_pass0 & SEEN_XREG)
171 CLEAR_X(); /* make sure we dont leek kernel memory */
172
173 /*
174 * If this filter needs to access skb data,
175 * loads r9 and r8 with :
176 * r9 = skb->len - skb->data_len
177 * r8 = skb->data
178 */
179 if (seen_or_pass0 & SEEN_DATAREF) {
180 if (offsetof(struct sk_buff, len) <= 127)
181 /* mov off8(%rdi),%r9d */
182 EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
183 else {
184 /* mov off32(%rdi),%r9d */
185 EMIT3(0x44, 0x8b, 0x8f);
186 EMIT(offsetof(struct sk_buff, len), 4);
187 }
188 if (is_imm8(offsetof(struct sk_buff, data_len)))
189 /* sub off8(%rdi),%r9d */
190 EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
191 else {
192 EMIT3(0x44, 0x2b, 0x8f);
193 EMIT(offsetof(struct sk_buff, data_len), 4);
194 }
195
196 if (is_imm8(offsetof(struct sk_buff, data)))
197 /* mov off8(%rdi),%r8 */
198 EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
199 else {
200 /* mov off32(%rdi),%r8 */
201 EMIT3(0x4c, 0x8b, 0x87);
202 EMIT(offsetof(struct sk_buff, data), 4);
203 }
204 }
205 }
206
207 switch (filter[0].code) {
208 case BPF_S_RET_K:
209 case BPF_S_LD_W_LEN:
210 case BPF_S_ANC_PROTOCOL:
211 case BPF_S_ANC_IFINDEX:
212 case BPF_S_ANC_MARK:
213 case BPF_S_ANC_RXHASH:
214 case BPF_S_ANC_CPU:
215 case BPF_S_ANC_QUEUE:
216 case BPF_S_LD_W_ABS:
217 case BPF_S_LD_H_ABS:
218 case BPF_S_LD_B_ABS:
219 /* first instruction sets A register (or is RET 'constant') */
220 break;
221 default:
222 /* make sure we dont leak kernel information to user */
223 CLEAR_A(); /* A = 0 */
224 }
225
226 for (i = 0; i < flen; i++) {
227 unsigned int K = filter[i].k;
228
229 switch (filter[i].code) {
230 case BPF_S_ALU_ADD_X: /* A += X; */
231 seen |= SEEN_XREG;
232 EMIT2(0x01, 0xd8); /* add %ebx,%eax */
233 break;
234 case BPF_S_ALU_ADD_K: /* A += K; */
235 if (!K)
236 break;
237 if (is_imm8(K))
238 EMIT3(0x83, 0xc0, K); /* add imm8,%eax */
239 else
240 EMIT1_off32(0x05, K); /* add imm32,%eax */
241 break;
242 case BPF_S_ALU_SUB_X: /* A -= X; */
243 seen |= SEEN_XREG;
244 EMIT2(0x29, 0xd8); /* sub %ebx,%eax */
245 break;
246 case BPF_S_ALU_SUB_K: /* A -= K */
247 if (!K)
248 break;
249 if (is_imm8(K))
250 EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
251 else
252 EMIT1_off32(0x2d, K); /* sub imm32,%eax */
253 break;
254 case BPF_S_ALU_MUL_X: /* A *= X; */
255 seen |= SEEN_XREG;
256 EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */
257 break;
258 case BPF_S_ALU_MUL_K: /* A *= K */
259 if (is_imm8(K))
260 EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
261 else {
262 EMIT2(0x69, 0xc0); /* imul imm32,%eax */
263 EMIT(K, 4);
264 }
265 break;
266 case BPF_S_ALU_DIV_X: /* A /= X; */
267 seen |= SEEN_XREG;
268 EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
269 if (pc_ret0 > 0) {
270 /* addrs[pc_ret0 - 1] is start address of target
271 * (addrs[i] - 4) is the address following this jmp
272 * ("xor %edx,%edx; div %ebx" being 4 bytes long)
273 */
274 EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
275 (addrs[i] - 4));
276 } else {
277 EMIT_COND_JMP(X86_JNE, 2 + 5);
278 CLEAR_A();
279 EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
280 }
281 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
282 break;
283 case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
284 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
285 EMIT(K, 4);
286 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
287 break;
288 case BPF_S_ALU_AND_X:
289 seen |= SEEN_XREG;
290 EMIT2(0x21, 0xd8); /* and %ebx,%eax */
291 break;
292 case BPF_S_ALU_AND_K:
293 if (K >= 0xFFFFFF00) {
294 EMIT2(0x24, K & 0xFF); /* and imm8,%al */
295 } else if (K >= 0xFFFF0000) {
296 EMIT2(0x66, 0x25); /* and imm16,%ax */
297 EMIT(K, 2);
298 } else {
299 EMIT1_off32(0x25, K); /* and imm32,%eax */
300 }
301 break;
302 case BPF_S_ALU_OR_X:
303 seen |= SEEN_XREG;
304 EMIT2(0x09, 0xd8); /* or %ebx,%eax */
305 break;
306 case BPF_S_ALU_OR_K:
307 if (is_imm8(K))
308 EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
309 else
310 EMIT1_off32(0x0d, K); /* or imm32,%eax */
311 break;
312 case BPF_S_ALU_LSH_X: /* A <<= X; */
313 seen |= SEEN_XREG;
314 EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */
315 break;
316 case BPF_S_ALU_LSH_K:
317 if (K == 0)
318 break;
319 else if (K == 1)
320 EMIT2(0xd1, 0xe0); /* shl %eax */
321 else
322 EMIT3(0xc1, 0xe0, K);
323 break;
324 case BPF_S_ALU_RSH_X: /* A >>= X; */
325 seen |= SEEN_XREG;
326 EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */
327 break;
328 case BPF_S_ALU_RSH_K: /* A >>= K; */
329 if (K == 0)
330 break;
331 else if (K == 1)
332 EMIT2(0xd1, 0xe8); /* shr %eax */
333 else
334 EMIT3(0xc1, 0xe8, K);
335 break;
336 case BPF_S_ALU_NEG:
337 EMIT2(0xf7, 0xd8); /* neg %eax */
338 break;
339 case BPF_S_RET_K:
340 if (!K) {
341 if (pc_ret0 == -1)
342 pc_ret0 = i;
343 CLEAR_A();
344 } else {
345 EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
346 }
347 /* fallinto */
348 case BPF_S_RET_A:
349 if (seen_or_pass0) {
350 if (i != flen - 1) {
351 EMIT_JMP(cleanup_addr - addrs[i]);
352 break;
353 }
354 if (seen_or_pass0 & SEEN_XREG)
355 EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */
356 EMIT1(0xc9); /* leaveq */
357 }
358 EMIT1(0xc3); /* ret */
359 break;
360 case BPF_S_MISC_TAX: /* X = A */
361 seen |= SEEN_XREG;
362 EMIT2(0x89, 0xc3); /* mov %eax,%ebx */
363 break;
364 case BPF_S_MISC_TXA: /* A = X */
365 seen |= SEEN_XREG;
366 EMIT2(0x89, 0xd8); /* mov %ebx,%eax */
367 break;
368 case BPF_S_LD_IMM: /* A = K */
369 if (!K)
370 CLEAR_A();
371 else
372 EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
373 break;
374 case BPF_S_LDX_IMM: /* X = K */
375 seen |= SEEN_XREG;
376 if (!K)
377 CLEAR_X();
378 else
379 EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
380 break;
381 case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
382 seen |= SEEN_MEM;
383 EMIT3(0x8b, 0x45, 0xf0 - K*4);
384 break;
385 case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
386 seen |= SEEN_XREG | SEEN_MEM;
387 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
388 break;
389 case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
390 seen |= SEEN_MEM;
391 EMIT3(0x89, 0x45, 0xf0 - K*4);
392 break;
393 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
394 seen |= SEEN_XREG | SEEN_MEM;
395 EMIT3(0x89, 0x5d, 0xf0 - K*4);
396 break;
397 case BPF_S_LD_W_LEN: /* A = skb->len; */
398 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
399 if (is_imm8(offsetof(struct sk_buff, len)))
400 /* mov off8(%rdi),%eax */
401 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
402 else {
403 EMIT2(0x8b, 0x87);
404 EMIT(offsetof(struct sk_buff, len), 4);
405 }
406 break;
407 case BPF_S_LDX_W_LEN: /* X = skb->len; */
408 seen |= SEEN_XREG;
409 if (is_imm8(offsetof(struct sk_buff, len)))
410 /* mov off8(%rdi),%ebx */
411 EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
412 else {
413 EMIT2(0x8b, 0x9f);
414 EMIT(offsetof(struct sk_buff, len), 4);
415 }
416 break;
417 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
418 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
419 if (is_imm8(offsetof(struct sk_buff, protocol))) {
420 /* movzwl off8(%rdi),%eax */
421 EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
422 } else {
423 EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
424 EMIT(offsetof(struct sk_buff, protocol), 4);
425 }
426 EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */
427 break;
428 case BPF_S_ANC_IFINDEX:
429 if (is_imm8(offsetof(struct sk_buff, dev))) {
430 /* movq off8(%rdi),%rax */
431 EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
432 } else {
433 EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
434 EMIT(offsetof(struct sk_buff, dev), 4);
435 }
436 EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */
437 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
438 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
439 EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */
440 EMIT(offsetof(struct net_device, ifindex), 4);
441 break;
442 case BPF_S_ANC_MARK:
443 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
444 if (is_imm8(offsetof(struct sk_buff, mark))) {
445 /* mov off8(%rdi),%eax */
446 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
447 } else {
448 EMIT2(0x8b, 0x87);
449 EMIT(offsetof(struct sk_buff, mark), 4);
450 }
451 break;
452 case BPF_S_ANC_RXHASH:
453 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
454 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
455 /* mov off8(%rdi),%eax */
456 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
457 } else {
458 EMIT2(0x8b, 0x87);
459 EMIT(offsetof(struct sk_buff, rxhash), 4);
460 }
461 break;
462 case BPF_S_ANC_QUEUE:
463 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
464 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
465 /* movzwl off8(%rdi),%eax */
466 EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
467 } else {
468 EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
469 EMIT(offsetof(struct sk_buff, queue_mapping), 4);
470 }
471 break;
472 case BPF_S_ANC_CPU:
473#ifdef CONFIG_SMP
474 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
475 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
476#else
477 CLEAR_A();
478#endif
479 break;
480 case BPF_S_LD_W_ABS:
481 func = CHOOSE_LOAD_FUNC(K, sk_load_word);
482common_load: seen |= SEEN_DATAREF;
483 t_offset = func - (image + addrs[i]);
484 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
485 EMIT1_off32(0xe8, t_offset); /* call */
486 break;
487 case BPF_S_LD_H_ABS:
488 func = CHOOSE_LOAD_FUNC(K, sk_load_half);
489 goto common_load;
490 case BPF_S_LD_B_ABS:
491 func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
492 goto common_load;
493 case BPF_S_LDX_B_MSH:
494 func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
495 seen |= SEEN_DATAREF | SEEN_XREG;
496 t_offset = func - (image + addrs[i]);
497 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
498 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
499 break;
500 case BPF_S_LD_W_IND:
501 func = sk_load_word;
502common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG;
503 t_offset = func - (image + addrs[i]);
504 if (K) {
505 if (is_imm8(K)) {
506 EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */
507 } else {
508 EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */
509 EMIT(K, 4);
510 }
511 } else {
512 EMIT2(0x89,0xde); /* mov %ebx,%esi */
513 }
514 EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */
515 break;
516 case BPF_S_LD_H_IND:
517 func = sk_load_half;
518 goto common_load_ind;
519 case BPF_S_LD_B_IND:
520 func = sk_load_byte;
521 goto common_load_ind;
522 case BPF_S_JMP_JA:
523 t_offset = addrs[i + K] - addrs[i];
524 EMIT_JMP(t_offset);
525 break;
526 COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
527 COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
528 COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
529 COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
530 COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
531 COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
532 COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
533 COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
534
535cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
536 t_offset = addrs[i + filter[i].jt] - addrs[i];
537
538 /* same targets, can avoid doing the test :) */
539 if (filter[i].jt == filter[i].jf) {
540 EMIT_JMP(t_offset);
541 break;
542 }
543
544 switch (filter[i].code) {
545 case BPF_S_JMP_JGT_X:
546 case BPF_S_JMP_JGE_X:
547 case BPF_S_JMP_JEQ_X:
548 seen |= SEEN_XREG;
549 EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
550 break;
551 case BPF_S_JMP_JSET_X:
552 seen |= SEEN_XREG;
553 EMIT2(0x85, 0xd8); /* test %ebx,%eax */
554 break;
555 case BPF_S_JMP_JEQ_K:
556 if (K == 0) {
557 EMIT2(0x85, 0xc0); /* test %eax,%eax */
558 break;
559 }
560 case BPF_S_JMP_JGT_K:
561 case BPF_S_JMP_JGE_K:
562 if (K <= 127)
563 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
564 else
565 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
566 break;
567 case BPF_S_JMP_JSET_K:
568 if (K <= 0xFF)
569 EMIT2(0xa8, K); /* test imm8,%al */
570 else if (!(K & 0xFFFF00FF))
571 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
572 else if (K <= 0xFFFF) {
573 EMIT2(0x66, 0xa9); /* test imm16,%ax */
574 EMIT(K, 2);
575 } else {
576 EMIT1_off32(0xa9, K); /* test imm32,%eax */
577 }
578 break;
579 }
580 if (filter[i].jt != 0) {
581 if (filter[i].jf && f_offset)
582 t_offset += is_near(f_offset) ? 2 : 5;
583 EMIT_COND_JMP(t_op, t_offset);
584 if (filter[i].jf)
585 EMIT_JMP(f_offset);
586 break;
587 }
588 EMIT_COND_JMP(f_op, f_offset);
589 break;
590 default:
591 /* hmm, too complex filter, give up with jit compiler */
592 goto out;
593 }
594 ilen = prog - temp;
595 if (image) {
596 if (unlikely(proglen + ilen > oldproglen)) {
597 pr_err("bpb_jit_compile fatal error\n");
598 kfree(addrs);
599 module_free(NULL, image);
600 return;
601 }
602 memcpy(image + proglen, temp, ilen);
603 }
604 proglen += ilen;
605 addrs[i] = proglen;
606 prog = temp;
607 }
608 /* last bpf instruction is always a RET :
609 * use it to give the cleanup instruction(s) addr
610 */
611 cleanup_addr = proglen - 1; /* ret */
612 if (seen_or_pass0)
613 cleanup_addr -= 1; /* leaveq */
614 if (seen_or_pass0 & SEEN_XREG)
615 cleanup_addr -= 4; /* mov -8(%rbp),%rbx */
616
617 if (image) {
618 if (proglen != oldproglen)
619 pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
620 break;
621 }
622 if (proglen == oldproglen) {
623 image = module_alloc(max_t(unsigned int,
624 proglen,
625 sizeof(struct work_struct)));
626 if (!image)
627 goto out;
628 }
629 oldproglen = proglen;
630 }
631 if (bpf_jit_enable > 1)
632 pr_err("flen=%d proglen=%u pass=%d image=%p\n",
633 flen, proglen, pass, image);
634
635 if (image) {
636 if (bpf_jit_enable > 1)
637 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS,
638 16, 1, image, proglen, false);
639
640 bpf_flush_icache(image, image + proglen);
641
642 fp->bpf_func = (void *)image;
643 }
644out:
645 kfree(addrs);
646 return;
647}
648
649static void jit_free_defer(struct work_struct *arg)
650{
651 module_free(NULL, arg);
652}
653
654/* run from softirq, we must use a work_struct to call
655 * module_free() from process context
656 */
657void bpf_jit_free(struct sk_filter *fp)
658{
659 if (fp->bpf_func != sk_run_filter) {
660 struct work_struct *work = (struct work_struct *)fp->bpf_func;
661
662 INIT_WORK(work, jit_free_defer);
663 schedule_work(work);
664 }
665}
1/* bpf_jit_comp.c : BPF JIT compiler
2 *
3 * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
4 * Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; version 2
9 * of the License.
10 */
11#include <linux/netdevice.h>
12#include <linux/filter.h>
13#include <linux/if_vlan.h>
14#include <asm/cacheflush.h>
15#include <linux/bpf.h>
16
17int bpf_jit_enable __read_mostly;
18
19/*
20 * assembly code in arch/x86/net/bpf_jit.S
21 */
22extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
23extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
24extern u8 sk_load_byte_positive_offset[];
25extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
26extern u8 sk_load_byte_negative_offset[];
27
28static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
29{
30 if (len == 1)
31 *ptr = bytes;
32 else if (len == 2)
33 *(u16 *)ptr = bytes;
34 else {
35 *(u32 *)ptr = bytes;
36 barrier();
37 }
38 return ptr + len;
39}
40
41#define EMIT(bytes, len) \
42 do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
43
44#define EMIT1(b1) EMIT(b1, 1)
45#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
46#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
47#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
48#define EMIT1_off32(b1, off) \
49 do {EMIT1(b1); EMIT(off, 4); } while (0)
50#define EMIT2_off32(b1, b2, off) \
51 do {EMIT2(b1, b2); EMIT(off, 4); } while (0)
52#define EMIT3_off32(b1, b2, b3, off) \
53 do {EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
54#define EMIT4_off32(b1, b2, b3, b4, off) \
55 do {EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
56
57static bool is_imm8(int value)
58{
59 return value <= 127 && value >= -128;
60}
61
62static bool is_simm32(s64 value)
63{
64 return value == (s64) (s32) value;
65}
66
67/* mov dst, src */
68#define EMIT_mov(DST, SRC) \
69 do {if (DST != SRC) \
70 EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
71 } while (0)
72
73static int bpf_size_to_x86_bytes(int bpf_size)
74{
75 if (bpf_size == BPF_W)
76 return 4;
77 else if (bpf_size == BPF_H)
78 return 2;
79 else if (bpf_size == BPF_B)
80 return 1;
81 else if (bpf_size == BPF_DW)
82 return 4; /* imm32 */
83 else
84 return 0;
85}
86
87/* list of x86 cond jumps opcodes (. + s8)
88 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
89 */
90#define X86_JB 0x72
91#define X86_JAE 0x73
92#define X86_JE 0x74
93#define X86_JNE 0x75
94#define X86_JBE 0x76
95#define X86_JA 0x77
96#define X86_JGE 0x7D
97#define X86_JG 0x7F
98
99static void bpf_flush_icache(void *start, void *end)
100{
101 mm_segment_t old_fs = get_fs();
102
103 set_fs(KERNEL_DS);
104 smp_wmb();
105 flush_icache_range((unsigned long)start, (unsigned long)end);
106 set_fs(old_fs);
107}
108
109#define CHOOSE_LOAD_FUNC(K, func) \
110 ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
111
112/* pick a register outside of BPF range for JIT internal work */
113#define AUX_REG (MAX_BPF_REG + 1)
114
115/* the following table maps BPF registers to x64 registers.
116 * x64 register r12 is unused, since if used as base address register
117 * in load/store instructions, it always needs an extra byte of encoding
118 */
119static const int reg2hex[] = {
120 [BPF_REG_0] = 0, /* rax */
121 [BPF_REG_1] = 7, /* rdi */
122 [BPF_REG_2] = 6, /* rsi */
123 [BPF_REG_3] = 2, /* rdx */
124 [BPF_REG_4] = 1, /* rcx */
125 [BPF_REG_5] = 0, /* r8 */
126 [BPF_REG_6] = 3, /* rbx callee saved */
127 [BPF_REG_7] = 5, /* r13 callee saved */
128 [BPF_REG_8] = 6, /* r14 callee saved */
129 [BPF_REG_9] = 7, /* r15 callee saved */
130 [BPF_REG_FP] = 5, /* rbp readonly */
131 [AUX_REG] = 3, /* r11 temp register */
132};
133
134/* is_ereg() == true if BPF register 'reg' maps to x64 r8..r15
135 * which need extra byte of encoding.
136 * rax,rcx,...,rbp have simpler encoding
137 */
138static bool is_ereg(u32 reg)
139{
140 return (1 << reg) & (BIT(BPF_REG_5) |
141 BIT(AUX_REG) |
142 BIT(BPF_REG_7) |
143 BIT(BPF_REG_8) |
144 BIT(BPF_REG_9));
145}
146
147/* add modifiers if 'reg' maps to x64 registers r8..r15 */
148static u8 add_1mod(u8 byte, u32 reg)
149{
150 if (is_ereg(reg))
151 byte |= 1;
152 return byte;
153}
154
155static u8 add_2mod(u8 byte, u32 r1, u32 r2)
156{
157 if (is_ereg(r1))
158 byte |= 1;
159 if (is_ereg(r2))
160 byte |= 4;
161 return byte;
162}
163
164/* encode 'dst_reg' register into x64 opcode 'byte' */
165static u8 add_1reg(u8 byte, u32 dst_reg)
166{
167 return byte + reg2hex[dst_reg];
168}
169
170/* encode 'dst_reg' and 'src_reg' registers into x64 opcode 'byte' */
171static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
172{
173 return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
174}
175
176static void jit_fill_hole(void *area, unsigned int size)
177{
178 /* fill whole space with int3 instructions */
179 memset(area, 0xcc, size);
180}
181
182struct jit_context {
183 int cleanup_addr; /* epilogue code offset */
184 bool seen_ld_abs;
185};
186
187/* maximum number of bytes emitted while JITing one eBPF insn */
188#define BPF_MAX_INSN_SIZE 128
189#define BPF_INSN_SAFETY 64
190
191#define STACKSIZE \
192 (MAX_BPF_STACK + \
193 32 /* space for rbx, r13, r14, r15 */ + \
194 8 /* space for skb_copy_bits() buffer */)
195
196#define PROLOGUE_SIZE 48
197
198/* emit x64 prologue code for BPF program and check it's size.
199 * bpf_tail_call helper will skip it while jumping into another program
200 */
201static void emit_prologue(u8 **pprog)
202{
203 u8 *prog = *pprog;
204 int cnt = 0;
205
206 EMIT1(0x55); /* push rbp */
207 EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
208
209 /* sub rsp, STACKSIZE */
210 EMIT3_off32(0x48, 0x81, 0xEC, STACKSIZE);
211
212 /* all classic BPF filters use R6(rbx) save it */
213
214 /* mov qword ptr [rbp-X],rbx */
215 EMIT3_off32(0x48, 0x89, 0x9D, -STACKSIZE);
216
217 /* bpf_convert_filter() maps classic BPF register X to R7 and uses R8
218 * as temporary, so all tcpdump filters need to spill/fill R7(r13) and
219 * R8(r14). R9(r15) spill could be made conditional, but there is only
220 * one 'bpf_error' return path out of helper functions inside bpf_jit.S
221 * The overhead of extra spill is negligible for any filter other
222 * than synthetic ones. Therefore not worth adding complexity.
223 */
224
225 /* mov qword ptr [rbp-X],r13 */
226 EMIT3_off32(0x4C, 0x89, 0xAD, -STACKSIZE + 8);
227 /* mov qword ptr [rbp-X],r14 */
228 EMIT3_off32(0x4C, 0x89, 0xB5, -STACKSIZE + 16);
229 /* mov qword ptr [rbp-X],r15 */
230 EMIT3_off32(0x4C, 0x89, 0xBD, -STACKSIZE + 24);
231
232 /* Clear the tail call counter (tail_call_cnt): for eBPF tail calls
233 * we need to reset the counter to 0. It's done in two instructions,
234 * resetting rax register to 0 (xor on eax gets 0 extended), and
235 * moving it to the counter location.
236 */
237
238 /* xor eax, eax */
239 EMIT2(0x31, 0xc0);
240 /* mov qword ptr [rbp-X], rax */
241 EMIT3_off32(0x48, 0x89, 0x85, -STACKSIZE + 32);
242
243 BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
244 *pprog = prog;
245}
246
247/* generate the following code:
248 * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
249 * if (index >= array->map.max_entries)
250 * goto out;
251 * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
252 * goto out;
253 * prog = array->ptrs[index];
254 * if (prog == NULL)
255 * goto out;
256 * goto *(prog->bpf_func + prologue_size);
257 * out:
258 */
259static void emit_bpf_tail_call(u8 **pprog)
260{
261 u8 *prog = *pprog;
262 int label1, label2, label3;
263 int cnt = 0;
264
265 /* rdi - pointer to ctx
266 * rsi - pointer to bpf_array
267 * rdx - index in bpf_array
268 */
269
270 /* if (index >= array->map.max_entries)
271 * goto out;
272 */
273 EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */
274 offsetof(struct bpf_array, map.max_entries));
275 EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */
276#define OFFSET1 47 /* number of bytes to jump */
277 EMIT2(X86_JBE, OFFSET1); /* jbe out */
278 label1 = cnt;
279
280 /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
281 * goto out;
282 */
283 EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */
284 EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
285#define OFFSET2 36
286 EMIT2(X86_JA, OFFSET2); /* ja out */
287 label2 = cnt;
288 EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
289 EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */
290
291 /* prog = array->ptrs[index]; */
292 EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */
293 offsetof(struct bpf_array, ptrs));
294 EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */
295
296 /* if (prog == NULL)
297 * goto out;
298 */
299 EMIT4(0x48, 0x83, 0xF8, 0x00); /* cmp rax, 0 */
300#define OFFSET3 10
301 EMIT2(X86_JE, OFFSET3); /* je out */
302 label3 = cnt;
303
304 /* goto *(prog->bpf_func + prologue_size); */
305 EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
306 offsetof(struct bpf_prog, bpf_func));
307 EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
308
309 /* now we're ready to jump into next BPF program
310 * rdi == ctx (1st arg)
311 * rax == prog->bpf_func + prologue_size
312 */
313 EMIT2(0xFF, 0xE0); /* jmp rax */
314
315 /* out: */
316 BUILD_BUG_ON(cnt - label1 != OFFSET1);
317 BUILD_BUG_ON(cnt - label2 != OFFSET2);
318 BUILD_BUG_ON(cnt - label3 != OFFSET3);
319 *pprog = prog;
320}
321
322
323static void emit_load_skb_data_hlen(u8 **pprog)
324{
325 u8 *prog = *pprog;
326 int cnt = 0;
327
328 /* r9d = skb->len - skb->data_len (headlen)
329 * r10 = skb->data
330 */
331 /* mov %r9d, off32(%rdi) */
332 EMIT3_off32(0x44, 0x8b, 0x8f, offsetof(struct sk_buff, len));
333
334 /* sub %r9d, off32(%rdi) */
335 EMIT3_off32(0x44, 0x2b, 0x8f, offsetof(struct sk_buff, data_len));
336
337 /* mov %r10, off32(%rdi) */
338 EMIT3_off32(0x4c, 0x8b, 0x97, offsetof(struct sk_buff, data));
339 *pprog = prog;
340}
341
342static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
343 int oldproglen, struct jit_context *ctx)
344{
345 struct bpf_insn *insn = bpf_prog->insnsi;
346 int insn_cnt = bpf_prog->len;
347 bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0);
348 bool seen_exit = false;
349 u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
350 int i, cnt = 0;
351 int proglen = 0;
352 u8 *prog = temp;
353
354 emit_prologue(&prog);
355
356 if (seen_ld_abs)
357 emit_load_skb_data_hlen(&prog);
358
359 for (i = 0; i < insn_cnt; i++, insn++) {
360 const s32 imm32 = insn->imm;
361 u32 dst_reg = insn->dst_reg;
362 u32 src_reg = insn->src_reg;
363 u8 b1 = 0, b2 = 0, b3 = 0;
364 s64 jmp_offset;
365 u8 jmp_cond;
366 bool reload_skb_data;
367 int ilen;
368 u8 *func;
369
370 switch (insn->code) {
371 /* ALU */
372 case BPF_ALU | BPF_ADD | BPF_X:
373 case BPF_ALU | BPF_SUB | BPF_X:
374 case BPF_ALU | BPF_AND | BPF_X:
375 case BPF_ALU | BPF_OR | BPF_X:
376 case BPF_ALU | BPF_XOR | BPF_X:
377 case BPF_ALU64 | BPF_ADD | BPF_X:
378 case BPF_ALU64 | BPF_SUB | BPF_X:
379 case BPF_ALU64 | BPF_AND | BPF_X:
380 case BPF_ALU64 | BPF_OR | BPF_X:
381 case BPF_ALU64 | BPF_XOR | BPF_X:
382 switch (BPF_OP(insn->code)) {
383 case BPF_ADD: b2 = 0x01; break;
384 case BPF_SUB: b2 = 0x29; break;
385 case BPF_AND: b2 = 0x21; break;
386 case BPF_OR: b2 = 0x09; break;
387 case BPF_XOR: b2 = 0x31; break;
388 }
389 if (BPF_CLASS(insn->code) == BPF_ALU64)
390 EMIT1(add_2mod(0x48, dst_reg, src_reg));
391 else if (is_ereg(dst_reg) || is_ereg(src_reg))
392 EMIT1(add_2mod(0x40, dst_reg, src_reg));
393 EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
394 break;
395
396 /* mov dst, src */
397 case BPF_ALU64 | BPF_MOV | BPF_X:
398 EMIT_mov(dst_reg, src_reg);
399 break;
400
401 /* mov32 dst, src */
402 case BPF_ALU | BPF_MOV | BPF_X:
403 if (is_ereg(dst_reg) || is_ereg(src_reg))
404 EMIT1(add_2mod(0x40, dst_reg, src_reg));
405 EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
406 break;
407
408 /* neg dst */
409 case BPF_ALU | BPF_NEG:
410 case BPF_ALU64 | BPF_NEG:
411 if (BPF_CLASS(insn->code) == BPF_ALU64)
412 EMIT1(add_1mod(0x48, dst_reg));
413 else if (is_ereg(dst_reg))
414 EMIT1(add_1mod(0x40, dst_reg));
415 EMIT2(0xF7, add_1reg(0xD8, dst_reg));
416 break;
417
418 case BPF_ALU | BPF_ADD | BPF_K:
419 case BPF_ALU | BPF_SUB | BPF_K:
420 case BPF_ALU | BPF_AND | BPF_K:
421 case BPF_ALU | BPF_OR | BPF_K:
422 case BPF_ALU | BPF_XOR | BPF_K:
423 case BPF_ALU64 | BPF_ADD | BPF_K:
424 case BPF_ALU64 | BPF_SUB | BPF_K:
425 case BPF_ALU64 | BPF_AND | BPF_K:
426 case BPF_ALU64 | BPF_OR | BPF_K:
427 case BPF_ALU64 | BPF_XOR | BPF_K:
428 if (BPF_CLASS(insn->code) == BPF_ALU64)
429 EMIT1(add_1mod(0x48, dst_reg));
430 else if (is_ereg(dst_reg))
431 EMIT1(add_1mod(0x40, dst_reg));
432
433 switch (BPF_OP(insn->code)) {
434 case BPF_ADD: b3 = 0xC0; break;
435 case BPF_SUB: b3 = 0xE8; break;
436 case BPF_AND: b3 = 0xE0; break;
437 case BPF_OR: b3 = 0xC8; break;
438 case BPF_XOR: b3 = 0xF0; break;
439 }
440
441 if (is_imm8(imm32))
442 EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
443 else
444 EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
445 break;
446
447 case BPF_ALU64 | BPF_MOV | BPF_K:
448 /* optimization: if imm32 is positive,
449 * use 'mov eax, imm32' (which zero-extends imm32)
450 * to save 2 bytes
451 */
452 if (imm32 < 0) {
453 /* 'mov rax, imm32' sign extends imm32 */
454 b1 = add_1mod(0x48, dst_reg);
455 b2 = 0xC7;
456 b3 = 0xC0;
457 EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32);
458 break;
459 }
460
461 case BPF_ALU | BPF_MOV | BPF_K:
462 /* optimization: if imm32 is zero, use 'xor <dst>,<dst>'
463 * to save 3 bytes.
464 */
465 if (imm32 == 0) {
466 if (is_ereg(dst_reg))
467 EMIT1(add_2mod(0x40, dst_reg, dst_reg));
468 b2 = 0x31; /* xor */
469 b3 = 0xC0;
470 EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
471 break;
472 }
473
474 /* mov %eax, imm32 */
475 if (is_ereg(dst_reg))
476 EMIT1(add_1mod(0x40, dst_reg));
477 EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
478 break;
479
480 case BPF_LD | BPF_IMM | BPF_DW:
481 if (insn[1].code != 0 || insn[1].src_reg != 0 ||
482 insn[1].dst_reg != 0 || insn[1].off != 0) {
483 /* verifier must catch invalid insns */
484 pr_err("invalid BPF_LD_IMM64 insn\n");
485 return -EINVAL;
486 }
487
488 /* optimization: if imm64 is zero, use 'xor <dst>,<dst>'
489 * to save 7 bytes.
490 */
491 if (insn[0].imm == 0 && insn[1].imm == 0) {
492 b1 = add_2mod(0x48, dst_reg, dst_reg);
493 b2 = 0x31; /* xor */
494 b3 = 0xC0;
495 EMIT3(b1, b2, add_2reg(b3, dst_reg, dst_reg));
496
497 insn++;
498 i++;
499 break;
500 }
501
502 /* movabsq %rax, imm64 */
503 EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
504 EMIT(insn[0].imm, 4);
505 EMIT(insn[1].imm, 4);
506
507 insn++;
508 i++;
509 break;
510
511 /* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
512 case BPF_ALU | BPF_MOD | BPF_X:
513 case BPF_ALU | BPF_DIV | BPF_X:
514 case BPF_ALU | BPF_MOD | BPF_K:
515 case BPF_ALU | BPF_DIV | BPF_K:
516 case BPF_ALU64 | BPF_MOD | BPF_X:
517 case BPF_ALU64 | BPF_DIV | BPF_X:
518 case BPF_ALU64 | BPF_MOD | BPF_K:
519 case BPF_ALU64 | BPF_DIV | BPF_K:
520 EMIT1(0x50); /* push rax */
521 EMIT1(0x52); /* push rdx */
522
523 if (BPF_SRC(insn->code) == BPF_X)
524 /* mov r11, src_reg */
525 EMIT_mov(AUX_REG, src_reg);
526 else
527 /* mov r11, imm32 */
528 EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
529
530 /* mov rax, dst_reg */
531 EMIT_mov(BPF_REG_0, dst_reg);
532
533 /* xor edx, edx
534 * equivalent to 'xor rdx, rdx', but one byte less
535 */
536 EMIT2(0x31, 0xd2);
537
538 if (BPF_SRC(insn->code) == BPF_X) {
539 /* if (src_reg == 0) return 0 */
540
541 /* cmp r11, 0 */
542 EMIT4(0x49, 0x83, 0xFB, 0x00);
543
544 /* jne .+9 (skip over pop, pop, xor and jmp) */
545 EMIT2(X86_JNE, 1 + 1 + 2 + 5);
546 EMIT1(0x5A); /* pop rdx */
547 EMIT1(0x58); /* pop rax */
548 EMIT2(0x31, 0xc0); /* xor eax, eax */
549
550 /* jmp cleanup_addr
551 * addrs[i] - 11, because there are 11 bytes
552 * after this insn: div, mov, pop, pop, mov
553 */
554 jmp_offset = ctx->cleanup_addr - (addrs[i] - 11);
555 EMIT1_off32(0xE9, jmp_offset);
556 }
557
558 if (BPF_CLASS(insn->code) == BPF_ALU64)
559 /* div r11 */
560 EMIT3(0x49, 0xF7, 0xF3);
561 else
562 /* div r11d */
563 EMIT3(0x41, 0xF7, 0xF3);
564
565 if (BPF_OP(insn->code) == BPF_MOD)
566 /* mov r11, rdx */
567 EMIT3(0x49, 0x89, 0xD3);
568 else
569 /* mov r11, rax */
570 EMIT3(0x49, 0x89, 0xC3);
571
572 EMIT1(0x5A); /* pop rdx */
573 EMIT1(0x58); /* pop rax */
574
575 /* mov dst_reg, r11 */
576 EMIT_mov(dst_reg, AUX_REG);
577 break;
578
579 case BPF_ALU | BPF_MUL | BPF_K:
580 case BPF_ALU | BPF_MUL | BPF_X:
581 case BPF_ALU64 | BPF_MUL | BPF_K:
582 case BPF_ALU64 | BPF_MUL | BPF_X:
583 EMIT1(0x50); /* push rax */
584 EMIT1(0x52); /* push rdx */
585
586 /* mov r11, dst_reg */
587 EMIT_mov(AUX_REG, dst_reg);
588
589 if (BPF_SRC(insn->code) == BPF_X)
590 /* mov rax, src_reg */
591 EMIT_mov(BPF_REG_0, src_reg);
592 else
593 /* mov rax, imm32 */
594 EMIT3_off32(0x48, 0xC7, 0xC0, imm32);
595
596 if (BPF_CLASS(insn->code) == BPF_ALU64)
597 EMIT1(add_1mod(0x48, AUX_REG));
598 else if (is_ereg(AUX_REG))
599 EMIT1(add_1mod(0x40, AUX_REG));
600 /* mul(q) r11 */
601 EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
602
603 /* mov r11, rax */
604 EMIT_mov(AUX_REG, BPF_REG_0);
605
606 EMIT1(0x5A); /* pop rdx */
607 EMIT1(0x58); /* pop rax */
608
609 /* mov dst_reg, r11 */
610 EMIT_mov(dst_reg, AUX_REG);
611 break;
612
613 /* shifts */
614 case BPF_ALU | BPF_LSH | BPF_K:
615 case BPF_ALU | BPF_RSH | BPF_K:
616 case BPF_ALU | BPF_ARSH | BPF_K:
617 case BPF_ALU64 | BPF_LSH | BPF_K:
618 case BPF_ALU64 | BPF_RSH | BPF_K:
619 case BPF_ALU64 | BPF_ARSH | BPF_K:
620 if (BPF_CLASS(insn->code) == BPF_ALU64)
621 EMIT1(add_1mod(0x48, dst_reg));
622 else if (is_ereg(dst_reg))
623 EMIT1(add_1mod(0x40, dst_reg));
624
625 switch (BPF_OP(insn->code)) {
626 case BPF_LSH: b3 = 0xE0; break;
627 case BPF_RSH: b3 = 0xE8; break;
628 case BPF_ARSH: b3 = 0xF8; break;
629 }
630 EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
631 break;
632
633 case BPF_ALU | BPF_LSH | BPF_X:
634 case BPF_ALU | BPF_RSH | BPF_X:
635 case BPF_ALU | BPF_ARSH | BPF_X:
636 case BPF_ALU64 | BPF_LSH | BPF_X:
637 case BPF_ALU64 | BPF_RSH | BPF_X:
638 case BPF_ALU64 | BPF_ARSH | BPF_X:
639
640 /* check for bad case when dst_reg == rcx */
641 if (dst_reg == BPF_REG_4) {
642 /* mov r11, dst_reg */
643 EMIT_mov(AUX_REG, dst_reg);
644 dst_reg = AUX_REG;
645 }
646
647 if (src_reg != BPF_REG_4) { /* common case */
648 EMIT1(0x51); /* push rcx */
649
650 /* mov rcx, src_reg */
651 EMIT_mov(BPF_REG_4, src_reg);
652 }
653
654 /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
655 if (BPF_CLASS(insn->code) == BPF_ALU64)
656 EMIT1(add_1mod(0x48, dst_reg));
657 else if (is_ereg(dst_reg))
658 EMIT1(add_1mod(0x40, dst_reg));
659
660 switch (BPF_OP(insn->code)) {
661 case BPF_LSH: b3 = 0xE0; break;
662 case BPF_RSH: b3 = 0xE8; break;
663 case BPF_ARSH: b3 = 0xF8; break;
664 }
665 EMIT2(0xD3, add_1reg(b3, dst_reg));
666
667 if (src_reg != BPF_REG_4)
668 EMIT1(0x59); /* pop rcx */
669
670 if (insn->dst_reg == BPF_REG_4)
671 /* mov dst_reg, r11 */
672 EMIT_mov(insn->dst_reg, AUX_REG);
673 break;
674
675 case BPF_ALU | BPF_END | BPF_FROM_BE:
676 switch (imm32) {
677 case 16:
678 /* emit 'ror %ax, 8' to swap lower 2 bytes */
679 EMIT1(0x66);
680 if (is_ereg(dst_reg))
681 EMIT1(0x41);
682 EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
683
684 /* emit 'movzwl eax, ax' */
685 if (is_ereg(dst_reg))
686 EMIT3(0x45, 0x0F, 0xB7);
687 else
688 EMIT2(0x0F, 0xB7);
689 EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
690 break;
691 case 32:
692 /* emit 'bswap eax' to swap lower 4 bytes */
693 if (is_ereg(dst_reg))
694 EMIT2(0x41, 0x0F);
695 else
696 EMIT1(0x0F);
697 EMIT1(add_1reg(0xC8, dst_reg));
698 break;
699 case 64:
700 /* emit 'bswap rax' to swap 8 bytes */
701 EMIT3(add_1mod(0x48, dst_reg), 0x0F,
702 add_1reg(0xC8, dst_reg));
703 break;
704 }
705 break;
706
707 case BPF_ALU | BPF_END | BPF_FROM_LE:
708 switch (imm32) {
709 case 16:
710 /* emit 'movzwl eax, ax' to zero extend 16-bit
711 * into 64 bit
712 */
713 if (is_ereg(dst_reg))
714 EMIT3(0x45, 0x0F, 0xB7);
715 else
716 EMIT2(0x0F, 0xB7);
717 EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
718 break;
719 case 32:
720 /* emit 'mov eax, eax' to clear upper 32-bits */
721 if (is_ereg(dst_reg))
722 EMIT1(0x45);
723 EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
724 break;
725 case 64:
726 /* nop */
727 break;
728 }
729 break;
730
731 /* ST: *(u8*)(dst_reg + off) = imm */
732 case BPF_ST | BPF_MEM | BPF_B:
733 if (is_ereg(dst_reg))
734 EMIT2(0x41, 0xC6);
735 else
736 EMIT1(0xC6);
737 goto st;
738 case BPF_ST | BPF_MEM | BPF_H:
739 if (is_ereg(dst_reg))
740 EMIT3(0x66, 0x41, 0xC7);
741 else
742 EMIT2(0x66, 0xC7);
743 goto st;
744 case BPF_ST | BPF_MEM | BPF_W:
745 if (is_ereg(dst_reg))
746 EMIT2(0x41, 0xC7);
747 else
748 EMIT1(0xC7);
749 goto st;
750 case BPF_ST | BPF_MEM | BPF_DW:
751 EMIT2(add_1mod(0x48, dst_reg), 0xC7);
752
753st: if (is_imm8(insn->off))
754 EMIT2(add_1reg(0x40, dst_reg), insn->off);
755 else
756 EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);
757
758 EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
759 break;
760
761 /* STX: *(u8*)(dst_reg + off) = src_reg */
762 case BPF_STX | BPF_MEM | BPF_B:
763 /* emit 'mov byte ptr [rax + off], al' */
764 if (is_ereg(dst_reg) || is_ereg(src_reg) ||
765 /* have to add extra byte for x86 SIL, DIL regs */
766 src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
767 EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
768 else
769 EMIT1(0x88);
770 goto stx;
771 case BPF_STX | BPF_MEM | BPF_H:
772 if (is_ereg(dst_reg) || is_ereg(src_reg))
773 EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
774 else
775 EMIT2(0x66, 0x89);
776 goto stx;
777 case BPF_STX | BPF_MEM | BPF_W:
778 if (is_ereg(dst_reg) || is_ereg(src_reg))
779 EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
780 else
781 EMIT1(0x89);
782 goto stx;
783 case BPF_STX | BPF_MEM | BPF_DW:
784 EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
785stx: if (is_imm8(insn->off))
786 EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
787 else
788 EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
789 insn->off);
790 break;
791
792 /* LDX: dst_reg = *(u8*)(src_reg + off) */
793 case BPF_LDX | BPF_MEM | BPF_B:
794 /* emit 'movzx rax, byte ptr [rax + off]' */
795 EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
796 goto ldx;
797 case BPF_LDX | BPF_MEM | BPF_H:
798 /* emit 'movzx rax, word ptr [rax + off]' */
799 EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
800 goto ldx;
801 case BPF_LDX | BPF_MEM | BPF_W:
802 /* emit 'mov eax, dword ptr [rax+0x14]' */
803 if (is_ereg(dst_reg) || is_ereg(src_reg))
804 EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
805 else
806 EMIT1(0x8B);
807 goto ldx;
808 case BPF_LDX | BPF_MEM | BPF_DW:
809 /* emit 'mov rax, qword ptr [rax+0x14]' */
810 EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
811ldx: /* if insn->off == 0 we can save one extra byte, but
812 * special case of x86 r13 which always needs an offset
813 * is not worth the hassle
814 */
815 if (is_imm8(insn->off))
816 EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off);
817 else
818 EMIT1_off32(add_2reg(0x80, src_reg, dst_reg),
819 insn->off);
820 break;
821
822 /* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */
823 case BPF_STX | BPF_XADD | BPF_W:
824 /* emit 'lock add dword ptr [rax + off], eax' */
825 if (is_ereg(dst_reg) || is_ereg(src_reg))
826 EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01);
827 else
828 EMIT2(0xF0, 0x01);
829 goto xadd;
830 case BPF_STX | BPF_XADD | BPF_DW:
831 EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01);
832xadd: if (is_imm8(insn->off))
833 EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
834 else
835 EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
836 insn->off);
837 break;
838
839 /* call */
840 case BPF_JMP | BPF_CALL:
841 func = (u8 *) __bpf_call_base + imm32;
842 jmp_offset = func - (image + addrs[i]);
843 if (seen_ld_abs) {
844 reload_skb_data = bpf_helper_changes_skb_data(func);
845 if (reload_skb_data) {
846 EMIT1(0x57); /* push %rdi */
847 jmp_offset += 22; /* pop, mov, sub, mov */
848 } else {
849 EMIT2(0x41, 0x52); /* push %r10 */
850 EMIT2(0x41, 0x51); /* push %r9 */
851 /* need to adjust jmp offset, since
852 * pop %r9, pop %r10 take 4 bytes after call insn
853 */
854 jmp_offset += 4;
855 }
856 }
857 if (!imm32 || !is_simm32(jmp_offset)) {
858 pr_err("unsupported bpf func %d addr %p image %p\n",
859 imm32, func, image);
860 return -EINVAL;
861 }
862 EMIT1_off32(0xE8, jmp_offset);
863 if (seen_ld_abs) {
864 if (reload_skb_data) {
865 EMIT1(0x5F); /* pop %rdi */
866 emit_load_skb_data_hlen(&prog);
867 } else {
868 EMIT2(0x41, 0x59); /* pop %r9 */
869 EMIT2(0x41, 0x5A); /* pop %r10 */
870 }
871 }
872 break;
873
874 case BPF_JMP | BPF_CALL | BPF_X:
875 emit_bpf_tail_call(&prog);
876 break;
877
878 /* cond jump */
879 case BPF_JMP | BPF_JEQ | BPF_X:
880 case BPF_JMP | BPF_JNE | BPF_X:
881 case BPF_JMP | BPF_JGT | BPF_X:
882 case BPF_JMP | BPF_JGE | BPF_X:
883 case BPF_JMP | BPF_JSGT | BPF_X:
884 case BPF_JMP | BPF_JSGE | BPF_X:
885 /* cmp dst_reg, src_reg */
886 EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x39,
887 add_2reg(0xC0, dst_reg, src_reg));
888 goto emit_cond_jmp;
889
890 case BPF_JMP | BPF_JSET | BPF_X:
891 /* test dst_reg, src_reg */
892 EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x85,
893 add_2reg(0xC0, dst_reg, src_reg));
894 goto emit_cond_jmp;
895
896 case BPF_JMP | BPF_JSET | BPF_K:
897 /* test dst_reg, imm32 */
898 EMIT1(add_1mod(0x48, dst_reg));
899 EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
900 goto emit_cond_jmp;
901
902 case BPF_JMP | BPF_JEQ | BPF_K:
903 case BPF_JMP | BPF_JNE | BPF_K:
904 case BPF_JMP | BPF_JGT | BPF_K:
905 case BPF_JMP | BPF_JGE | BPF_K:
906 case BPF_JMP | BPF_JSGT | BPF_K:
907 case BPF_JMP | BPF_JSGE | BPF_K:
908 /* cmp dst_reg, imm8/32 */
909 EMIT1(add_1mod(0x48, dst_reg));
910
911 if (is_imm8(imm32))
912 EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
913 else
914 EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);
915
916emit_cond_jmp: /* convert BPF opcode to x86 */
917 switch (BPF_OP(insn->code)) {
918 case BPF_JEQ:
919 jmp_cond = X86_JE;
920 break;
921 case BPF_JSET:
922 case BPF_JNE:
923 jmp_cond = X86_JNE;
924 break;
925 case BPF_JGT:
926 /* GT is unsigned '>', JA in x86 */
927 jmp_cond = X86_JA;
928 break;
929 case BPF_JGE:
930 /* GE is unsigned '>=', JAE in x86 */
931 jmp_cond = X86_JAE;
932 break;
933 case BPF_JSGT:
934 /* signed '>', GT in x86 */
935 jmp_cond = X86_JG;
936 break;
937 case BPF_JSGE:
938 /* signed '>=', GE in x86 */
939 jmp_cond = X86_JGE;
940 break;
941 default: /* to silence gcc warning */
942 return -EFAULT;
943 }
944 jmp_offset = addrs[i + insn->off] - addrs[i];
945 if (is_imm8(jmp_offset)) {
946 EMIT2(jmp_cond, jmp_offset);
947 } else if (is_simm32(jmp_offset)) {
948 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
949 } else {
950 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
951 return -EFAULT;
952 }
953
954 break;
955
956 case BPF_JMP | BPF_JA:
957 jmp_offset = addrs[i + insn->off] - addrs[i];
958 if (!jmp_offset)
959 /* optimize out nop jumps */
960 break;
961emit_jmp:
962 if (is_imm8(jmp_offset)) {
963 EMIT2(0xEB, jmp_offset);
964 } else if (is_simm32(jmp_offset)) {
965 EMIT1_off32(0xE9, jmp_offset);
966 } else {
967 pr_err("jmp gen bug %llx\n", jmp_offset);
968 return -EFAULT;
969 }
970 break;
971
972 case BPF_LD | BPF_IND | BPF_W:
973 func = sk_load_word;
974 goto common_load;
975 case BPF_LD | BPF_ABS | BPF_W:
976 func = CHOOSE_LOAD_FUNC(imm32, sk_load_word);
977common_load:
978 ctx->seen_ld_abs = seen_ld_abs = true;
979 jmp_offset = func - (image + addrs[i]);
980 if (!func || !is_simm32(jmp_offset)) {
981 pr_err("unsupported bpf func %d addr %p image %p\n",
982 imm32, func, image);
983 return -EINVAL;
984 }
985 if (BPF_MODE(insn->code) == BPF_ABS) {
986 /* mov %esi, imm32 */
987 EMIT1_off32(0xBE, imm32);
988 } else {
989 /* mov %rsi, src_reg */
990 EMIT_mov(BPF_REG_2, src_reg);
991 if (imm32) {
992 if (is_imm8(imm32))
993 /* add %esi, imm8 */
994 EMIT3(0x83, 0xC6, imm32);
995 else
996 /* add %esi, imm32 */
997 EMIT2_off32(0x81, 0xC6, imm32);
998 }
999 }
1000 /* skb pointer is in R6 (%rbx), it will be copied into
1001 * %rdi if skb_copy_bits() call is necessary.
1002 * sk_load_* helpers also use %r10 and %r9d.
1003 * See bpf_jit.S
1004 */
1005 EMIT1_off32(0xE8, jmp_offset); /* call */
1006 break;
1007
1008 case BPF_LD | BPF_IND | BPF_H:
1009 func = sk_load_half;
1010 goto common_load;
1011 case BPF_LD | BPF_ABS | BPF_H:
1012 func = CHOOSE_LOAD_FUNC(imm32, sk_load_half);
1013 goto common_load;
1014 case BPF_LD | BPF_IND | BPF_B:
1015 func = sk_load_byte;
1016 goto common_load;
1017 case BPF_LD | BPF_ABS | BPF_B:
1018 func = CHOOSE_LOAD_FUNC(imm32, sk_load_byte);
1019 goto common_load;
1020
1021 case BPF_JMP | BPF_EXIT:
1022 if (seen_exit) {
1023 jmp_offset = ctx->cleanup_addr - addrs[i];
1024 goto emit_jmp;
1025 }
1026 seen_exit = true;
1027 /* update cleanup_addr */
1028 ctx->cleanup_addr = proglen;
1029 /* mov rbx, qword ptr [rbp-X] */
1030 EMIT3_off32(0x48, 0x8B, 0x9D, -STACKSIZE);
1031 /* mov r13, qword ptr [rbp-X] */
1032 EMIT3_off32(0x4C, 0x8B, 0xAD, -STACKSIZE + 8);
1033 /* mov r14, qword ptr [rbp-X] */
1034 EMIT3_off32(0x4C, 0x8B, 0xB5, -STACKSIZE + 16);
1035 /* mov r15, qword ptr [rbp-X] */
1036 EMIT3_off32(0x4C, 0x8B, 0xBD, -STACKSIZE + 24);
1037
1038 EMIT1(0xC9); /* leave */
1039 EMIT1(0xC3); /* ret */
1040 break;
1041
1042 default:
1043 /* By design x64 JIT should support all BPF instructions
1044 * This error will be seen if new instruction was added
1045 * to interpreter, but not to JIT
1046 * or if there is junk in bpf_prog
1047 */
1048 pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
1049 return -EINVAL;
1050 }
1051
1052 ilen = prog - temp;
1053 if (ilen > BPF_MAX_INSN_SIZE) {
1054 pr_err("bpf_jit_compile fatal insn size error\n");
1055 return -EFAULT;
1056 }
1057
1058 if (image) {
1059 if (unlikely(proglen + ilen > oldproglen)) {
1060 pr_err("bpf_jit_compile fatal error\n");
1061 return -EFAULT;
1062 }
1063 memcpy(image + proglen, temp, ilen);
1064 }
1065 proglen += ilen;
1066 addrs[i] = proglen;
1067 prog = temp;
1068 }
1069 return proglen;
1070}
1071
1072void bpf_jit_compile(struct bpf_prog *prog)
1073{
1074}
1075
1076void bpf_int_jit_compile(struct bpf_prog *prog)
1077{
1078 struct bpf_binary_header *header = NULL;
1079 int proglen, oldproglen = 0;
1080 struct jit_context ctx = {};
1081 u8 *image = NULL;
1082 int *addrs;
1083 int pass;
1084 int i;
1085
1086 if (!bpf_jit_enable)
1087 return;
1088
1089 if (!prog || !prog->len)
1090 return;
1091
1092 addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
1093 if (!addrs)
1094 return;
1095
1096 /* Before first pass, make a rough estimation of addrs[]
1097 * each bpf instruction is translated to less than 64 bytes
1098 */
1099 for (proglen = 0, i = 0; i < prog->len; i++) {
1100 proglen += 64;
1101 addrs[i] = proglen;
1102 }
1103 ctx.cleanup_addr = proglen;
1104
1105 /* JITed image shrinks with every pass and the loop iterates
1106 * until the image stops shrinking. Very large bpf programs
1107 * may converge on the last pass. In such case do one more
1108 * pass to emit the final image
1109 */
1110 for (pass = 0; pass < 10 || image; pass++) {
1111 proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
1112 if (proglen <= 0) {
1113 image = NULL;
1114 if (header)
1115 bpf_jit_binary_free(header);
1116 goto out;
1117 }
1118 if (image) {
1119 if (proglen != oldproglen) {
1120 pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
1121 proglen, oldproglen);
1122 goto out;
1123 }
1124 break;
1125 }
1126 if (proglen == oldproglen) {
1127 header = bpf_jit_binary_alloc(proglen, &image,
1128 1, jit_fill_hole);
1129 if (!header)
1130 goto out;
1131 }
1132 oldproglen = proglen;
1133 }
1134
1135 if (bpf_jit_enable > 1)
1136 bpf_jit_dump(prog->len, proglen, pass + 1, image);
1137
1138 if (image) {
1139 bpf_flush_icache(header, image + proglen);
1140 set_memory_ro((unsigned long)header, header->pages);
1141 prog->bpf_func = (void *)image;
1142 prog->jited = 1;
1143 }
1144out:
1145 kfree(addrs);
1146}
1147
1148void bpf_jit_free(struct bpf_prog *fp)
1149{
1150 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
1151 struct bpf_binary_header *header = (void *)addr;
1152
1153 if (!fp->jited)
1154 goto free_filter;
1155
1156 set_memory_rw(addr, header->pages);
1157 bpf_jit_binary_free(header);
1158
1159free_filter:
1160 bpf_prog_unlock_free(fp);
1161}