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tcp: remove bad timeout logic in fast recovery
[mirror_ubuntu-hirsute-kernel.git] / arch / x86 / net / bpf_jit_comp.c
CommitLineData
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>
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 */
28int bpf_jit_enable __read_mostly;
29
30/*
31 * assembly code in arch/x86/net/bpf_jit.S
32 */
33extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
a998d434
JS		 34extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
35extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[];
36extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
37extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[];
0a14842f
ED		 38
39static 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
63static inline bool is_imm8(int value)
64{
65 return value <= 127 && value >= -128;
66}
67
68static inline bool is_near(int offset)
69{
70 return offset <= 127 && offset >= -128;
71}
72
73#define EMIT_JMP(offset) \
74do { \
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) \
94do { \
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
114static 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 126
3b58908a
ED		 127/* Helper to find the offset of pkt_type in sk_buff
128 * We want to make sure its still a 3bit field starting at a byte boundary.
129 */
130#define PKT_TYPE_MAX 7
131static int pkt_type_offset(void)
132{
133 struct sk_buff skb_probe = {
134 .pkt_type = ~0,
135 };
136 char *ct = (char *)&skb_probe;
137 unsigned int off;
138
139 for (off = 0; off < sizeof(struct sk_buff); off++) {
140 if (ct[off] == PKT_TYPE_MAX)
141 return off;
142 }
143 pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
144 return -1;
145}
146
0a14842f
ED		 147void bpf_jit_compile(struct sk_filter *fp)
148{
149 u8 temp[64];
150 u8 *prog;
151 unsigned int proglen, oldproglen = 0;
152 int ilen, i;
153 int t_offset, f_offset;
154 u8 t_op, f_op, seen = 0, pass;
155 u8 *image = NULL;
156 u8 *func;
157 int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
158 unsigned int cleanup_addr; /* epilogue code offset */
159 unsigned int *addrs;
160 const struct sock_filter *filter = fp->insns;
161 int flen = fp->len;
162
163 if (!bpf_jit_enable)
164 return;
165
166 addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
167 if (addrs == NULL)
168 return;
169
170 /* Before first pass, make a rough estimation of addrs[]
171 * each bpf instruction is translated to less than 64 bytes
172 */
173 for (proglen = 0, i = 0; i < flen; i++) {
174 proglen += 64;
175 addrs[i] = proglen;
176 }
177 cleanup_addr = proglen; /* epilogue address */
178
179 for (pass = 0; pass < 10; pass++) {
d00a9dd2 180 u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
0a14842f
ED		 181 /* no prologue/epilogue for trivial filters (RET something) */
182 proglen = 0;
183 prog = temp;
184
d00a9dd2 185 if (seen_or_pass0) {
0a14842f
ED		 186 EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
187 EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */
188 /* note : must save %rbx in case bpf_error is hit */
d00a9dd2 189 if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
0a14842f 190 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
d00a9dd2 191 if (seen_or_pass0 & SEEN_XREG)
0a14842f
ED		 192 CLEAR_X(); /* make sure we dont leek kernel memory */
193
194 /*
195 * If this filter needs to access skb data,
196 * loads r9 and r8 with :
197 * r9 = skb->len - skb->data_len
198 * r8 = skb->data
199 */
d00a9dd2 200 if (seen_or_pass0 & SEEN_DATAREF) {
0a14842f
ED		 201 if (offsetof(struct sk_buff, len) <= 127)
202 /* mov off8(%rdi),%r9d */
203 EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
204 else {
205 /* mov off32(%rdi),%r9d */
206 EMIT3(0x44, 0x8b, 0x8f);
207 EMIT(offsetof(struct sk_buff, len), 4);
208 }
209 if (is_imm8(offsetof(struct sk_buff, data_len)))
210 /* sub off8(%rdi),%r9d */
211 EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
212 else {
213 EMIT3(0x44, 0x2b, 0x8f);
214 EMIT(offsetof(struct sk_buff, data_len), 4);
215 }
216
217 if (is_imm8(offsetof(struct sk_buff, data)))
218 /* mov off8(%rdi),%r8 */
219 EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
220 else {
221 /* mov off32(%rdi),%r8 */
222 EMIT3(0x4c, 0x8b, 0x87);
223 EMIT(offsetof(struct sk_buff, data), 4);
224 }
225 }
226 }
227
228 switch (filter[0].code) {
229 case BPF_S_RET_K:
230 case BPF_S_LD_W_LEN:
231 case BPF_S_ANC_PROTOCOL:
232 case BPF_S_ANC_IFINDEX:
233 case BPF_S_ANC_MARK:
234 case BPF_S_ANC_RXHASH:
235 case BPF_S_ANC_CPU:
855ddb56
ED		 236 case BPF_S_ANC_VLAN_TAG:
237 case BPF_S_ANC_VLAN_TAG_PRESENT:
0a14842f 238 case BPF_S_ANC_QUEUE:
3b58908a 239 case BPF_S_ANC_PKTTYPE:
0a14842f
ED		 240 case BPF_S_LD_W_ABS:
241 case BPF_S_LD_H_ABS:
242 case BPF_S_LD_B_ABS:
243 /* first instruction sets A register (or is RET 'constant') */
244 break;
245 default:
246 /* make sure we dont leak kernel information to user */
247 CLEAR_A(); /* A = 0 */
248 }
249
250 for (i = 0; i < flen; i++) {
251 unsigned int K = filter[i].k;
252
253 switch (filter[i].code) {
254 case BPF_S_ALU_ADD_X: /* A += X; */
255 seen |= SEEN_XREG;
256 EMIT2(0x01, 0xd8); /* add %ebx,%eax */
257 break;
258 case BPF_S_ALU_ADD_K: /* A += K; */
259 if (!K)
260 break;
261 if (is_imm8(K))
262 EMIT3(0x83, 0xc0, K); /* add imm8,%eax */
263 else
264 EMIT1_off32(0x05, K); /* add imm32,%eax */
265 break;
266 case BPF_S_ALU_SUB_X: /* A -= X; */
267 seen |= SEEN_XREG;
268 EMIT2(0x29, 0xd8); /* sub %ebx,%eax */
269 break;
270 case BPF_S_ALU_SUB_K: /* A -= K */
271 if (!K)
272 break;
273 if (is_imm8(K))
274 EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
275 else
276 EMIT1_off32(0x2d, K); /* sub imm32,%eax */
277 break;
278 case BPF_S_ALU_MUL_X: /* A *= X; */
279 seen |= SEEN_XREG;
280 EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */
281 break;
282 case BPF_S_ALU_MUL_K: /* A *= K */
283 if (is_imm8(K))
284 EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
285 else {
286 EMIT2(0x69, 0xc0); /* imul imm32,%eax */
287 EMIT(K, 4);
288 }
289 break;
290 case BPF_S_ALU_DIV_X: /* A /= X; */
291 seen |= SEEN_XREG;
292 EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
d00a9dd2
ED		 293 if (pc_ret0 > 0) {
294 /* addrs[pc_ret0 - 1] is start address of target
295 * (addrs[i] - 4) is the address following this jmp
296 * ("xor %edx,%edx; div %ebx" being 4 bytes long)
297 */
298 EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
299 (addrs[i] - 4));
300 } else {
0a14842f
ED		 301 EMIT_COND_JMP(X86_JNE, 2 + 5);
302 CLEAR_A();
303 EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
304 }
305 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
306 break;
280050cc
ED		 307 case BPF_S_ALU_MOD_X: /* A %= X; */
308 seen |= SEEN_XREG;
309 EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
310 if (pc_ret0 > 0) {
311 /* addrs[pc_ret0 - 1] is start address of target
312 * (addrs[i] - 6) is the address following this jmp
313 * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long)
314 */
315 EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
316 (addrs[i] - 6));
317 } else {
318 EMIT_COND_JMP(X86_JNE, 2 + 5);
319 CLEAR_A();
320 EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */
321 }
322 EMIT2(0x31, 0xd2); /* xor %edx,%edx */
323 EMIT2(0xf7, 0xf3); /* div %ebx */
324 EMIT2(0x89, 0xd0); /* mov %edx,%eax */
325 break;
326 case BPF_S_ALU_MOD_K: /* A %= K; */
327 EMIT2(0x31, 0xd2); /* xor %edx,%edx */
328 EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
329 EMIT2(0xf7, 0xf1); /* div %ecx */
330 EMIT2(0x89, 0xd0); /* mov %edx,%eax */
331 break;
0a14842f
ED		 332 case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
333 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
334 EMIT(K, 4);
335 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
336 break;
337 case BPF_S_ALU_AND_X:
338 seen |= SEEN_XREG;
339 EMIT2(0x21, 0xd8); /* and %ebx,%eax */
340 break;
341 case BPF_S_ALU_AND_K:
342 if (K >= 0xFFFFFF00) {
343 EMIT2(0x24, K & 0xFF); /* and imm8,%al */
344 } else if (K >= 0xFFFF0000) {
345 EMIT2(0x66, 0x25); /* and imm16,%ax */
1d24fb36 346 EMIT(K, 2);
0a14842f
ED		 347 } else {
348 EMIT1_off32(0x25, K); /* and imm32,%eax */
349 }
350 break;
351 case BPF_S_ALU_OR_X:
352 seen |= SEEN_XREG;
353 EMIT2(0x09, 0xd8); /* or %ebx,%eax */
354 break;
355 case BPF_S_ALU_OR_K:
356 if (is_imm8(K))
357 EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
358 else
359 EMIT1_off32(0x0d, K); /* or imm32,%eax */
4bfaddf1
ED		 360 break;
361 case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
82c93fcc 362 case BPF_S_ALU_XOR_X:
4bfaddf1
ED		 363 seen |= SEEN_XREG;
364 EMIT2(0x31, 0xd8); /* xor %ebx,%eax */
82c93fcc
DB		 365 break;
366 case BPF_S_ALU_XOR_K: /* A ^= K; */
367 if (K == 0)
368 break;
369 if (is_imm8(K))
370 EMIT3(0x83, 0xf0, K); /* xor imm8,%eax */
371 else
372 EMIT1_off32(0x35, K); /* xor imm32,%eax */
0a14842f
ED		 373 break;
374 case BPF_S_ALU_LSH_X: /* A <<= X; */
375 seen |= SEEN_XREG;
376 EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */
377 break;
378 case BPF_S_ALU_LSH_K:
379 if (K == 0)
380 break;
381 else if (K == 1)
382 EMIT2(0xd1, 0xe0); /* shl %eax */
383 else
384 EMIT3(0xc1, 0xe0, K);
385 break;
386 case BPF_S_ALU_RSH_X: /* A >>= X; */
387 seen |= SEEN_XREG;
388 EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */
389 break;
390 case BPF_S_ALU_RSH_K: /* A >>= K; */
391 if (K == 0)
392 break;
393 else if (K == 1)
394 EMIT2(0xd1, 0xe8); /* shr %eax */
395 else
396 EMIT3(0xc1, 0xe8, K);
397 break;
398 case BPF_S_ALU_NEG:
399 EMIT2(0xf7, 0xd8); /* neg %eax */
400 break;
401 case BPF_S_RET_K:
402 if (!K) {
403 if (pc_ret0 == -1)
404 pc_ret0 = i;
405 CLEAR_A();
406 } else {
407 EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
408 }
409 /* fallinto */
410 case BPF_S_RET_A:
d00a9dd2 411 if (seen_or_pass0) {
0a14842f
ED		 412 if (i != flen - 1) {
413 EMIT_JMP(cleanup_addr - addrs[i]);
414 break;
415 }
d00a9dd2 416 if (seen_or_pass0 & SEEN_XREG)
0a14842f
ED		 417 EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */
418 EMIT1(0xc9); /* leaveq */
419 }
420 EMIT1(0xc3); /* ret */
421 break;
422 case BPF_S_MISC_TAX: /* X = A */
423 seen |= SEEN_XREG;
424 EMIT2(0x89, 0xc3); /* mov %eax,%ebx */
425 break;
426 case BPF_S_MISC_TXA: /* A = X */
427 seen |= SEEN_XREG;
428 EMIT2(0x89, 0xd8); /* mov %ebx,%eax */
429 break;
430 case BPF_S_LD_IMM: /* A = K */
431 if (!K)
432 CLEAR_A();
433 else
434 EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
435 break;
436 case BPF_S_LDX_IMM: /* X = K */
437 seen |= SEEN_XREG;
438 if (!K)
439 CLEAR_X();
440 else
441 EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
442 break;
443 case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
444 seen |= SEEN_MEM;
445 EMIT3(0x8b, 0x45, 0xf0 - K*4);
446 break;
447 case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
448 seen |= SEEN_XREG | SEEN_MEM;
449 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
450 break;
451 case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
452 seen |= SEEN_MEM;
453 EMIT3(0x89, 0x45, 0xf0 - K*4);
454 break;
455 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
456 seen |= SEEN_XREG | SEEN_MEM;
457 EMIT3(0x89, 0x5d, 0xf0 - K*4);
458 break;
459 case BPF_S_LD_W_LEN: /* A = skb->len; */
460 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
461 if (is_imm8(offsetof(struct sk_buff, len)))
462 /* mov off8(%rdi),%eax */
463 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
464 else {
465 EMIT2(0x8b, 0x87);
466 EMIT(offsetof(struct sk_buff, len), 4);
467 }
468 break;
469 case BPF_S_LDX_W_LEN: /* X = skb->len; */
470 seen |= SEEN_XREG;
471 if (is_imm8(offsetof(struct sk_buff, len)))
472 /* mov off8(%rdi),%ebx */
473 EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
474 else {
475 EMIT2(0x8b, 0x9f);
476 EMIT(offsetof(struct sk_buff, len), 4);
477 }
478 break;
479 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
480 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
481 if (is_imm8(offsetof(struct sk_buff, protocol))) {
482 /* movzwl off8(%rdi),%eax */
483 EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
484 } else {
485 EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
486 EMIT(offsetof(struct sk_buff, protocol), 4);
487 }
488 EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */
489 break;
490 case BPF_S_ANC_IFINDEX:
491 if (is_imm8(offsetof(struct sk_buff, dev))) {
492 /* movq off8(%rdi),%rax */
493 EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
494 } else {
495 EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
496 EMIT(offsetof(struct sk_buff, dev), 4);
497 }
498 EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */
499 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
500 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
501 EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */
502 EMIT(offsetof(struct net_device, ifindex), 4);
503 break;
504 case BPF_S_ANC_MARK:
505 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
506 if (is_imm8(offsetof(struct sk_buff, mark))) {
507 /* mov off8(%rdi),%eax */
508 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
509 } else {
510 EMIT2(0x8b, 0x87);
511 EMIT(offsetof(struct sk_buff, mark), 4);
512 }
513 break;
514 case BPF_S_ANC_RXHASH:
515 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
516 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
517 /* mov off8(%rdi),%eax */
518 EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
519 } else {
520 EMIT2(0x8b, 0x87);
521 EMIT(offsetof(struct sk_buff, rxhash), 4);
522 }
523 break;
524 case BPF_S_ANC_QUEUE:
525 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
526 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
527 /* movzwl off8(%rdi),%eax */
528 EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
529 } else {
530 EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
531 EMIT(offsetof(struct sk_buff, queue_mapping), 4);
532 }
533 break;
534 case BPF_S_ANC_CPU:
535#ifdef CONFIG_SMP
536 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
537 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
538#else
539 CLEAR_A();
540#endif
541 break;
855ddb56
ED		 542 case BPF_S_ANC_VLAN_TAG:
543 case BPF_S_ANC_VLAN_TAG_PRESENT:
544 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
545 if (is_imm8(offsetof(struct sk_buff, vlan_tci))) {
546 /* movzwl off8(%rdi),%eax */
547 EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci));
548 } else {
549 EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
550 EMIT(offsetof(struct sk_buff, vlan_tci), 4);
551 }
552 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
553 if (filter[i].code == BPF_S_ANC_VLAN_TAG) {
554 EMIT3(0x80, 0xe4, 0xef); /* and $0xef,%ah */
555 } else {
556 EMIT3(0xc1, 0xe8, 0x0c); /* shr $0xc,%eax */
557 EMIT3(0x83, 0xe0, 0x01); /* and $0x1,%eax */
558 }
559 break;
3b58908a
ED		 560 case BPF_S_ANC_PKTTYPE:
561 {
562 int off = pkt_type_offset();
563
564 if (off < 0)
565 goto out;
566 if (is_imm8(off)) {
567 /* movzbl off8(%rdi),%eax */
568 EMIT4(0x0f, 0xb6, 0x47, off);
569 } else {
570 /* movbl off32(%rdi),%eax */
571 EMIT3(0x0f, 0xb6, 0x87);
572 EMIT(off, 4);
573 }
574 EMIT3(0x83, 0xe0, PKT_TYPE_MAX); /* and $0x7,%eax */
575 break;
576 }
0a14842f 577 case BPF_S_LD_W_ABS:
a998d434 578 func = CHOOSE_LOAD_FUNC(K, sk_load_word);
0a14842f 579common_load: seen |= SEEN_DATAREF;
0a14842f
ED		 580 t_offset = func - (image + addrs[i]);
581 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
582 EMIT1_off32(0xe8, t_offset); /* call */
583 break;
584 case BPF_S_LD_H_ABS:
a998d434 585 func = CHOOSE_LOAD_FUNC(K, sk_load_half);
0a14842f
ED		 586 goto common_load;
587 case BPF_S_LD_B_ABS:
a998d434 588 func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
0a14842f
ED		 589 goto common_load;
590 case BPF_S_LDX_B_MSH:
a998d434 591 func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
0a14842f 592 seen |= SEEN_DATAREF | SEEN_XREG;
a998d434 593 t_offset = func - (image + addrs[i]);
0a14842f
ED		 594 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
595 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
596 break;
597 case BPF_S_LD_W_IND:
a998d434 598 func = sk_load_word;
0a14842f
ED		 599common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG;
600 t_offset = func - (image + addrs[i]);
a998d434
JS		 601 if (K) {
602 if (is_imm8(K)) {
603 EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */
604 } else {
605 EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */
606 EMIT(K, 4);
607 }
608 } else {
609 EMIT2(0x89,0xde); /* mov %ebx,%esi */
610 }
0a14842f
ED		 611 EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */
612 break;
613 case BPF_S_LD_H_IND:
a998d434 614 func = sk_load_half;
0a14842f
ED		 615 goto common_load_ind;
616 case BPF_S_LD_B_IND:
a998d434 617 func = sk_load_byte;
0a14842f
ED		 618 goto common_load_ind;
619 case BPF_S_JMP_JA:
620 t_offset = addrs[i + K] - addrs[i];
621 EMIT_JMP(t_offset);
622 break;
623 COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
624 COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
625 COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
626 COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
627 COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
628 COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
629 COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
630 COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
631
632cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
633 t_offset = addrs[i + filter[i].jt] - addrs[i];
634
635 /* same targets, can avoid doing the test :) */
636 if (filter[i].jt == filter[i].jf) {
637 EMIT_JMP(t_offset);
638 break;
639 }
640
641 switch (filter[i].code) {
642 case BPF_S_JMP_JGT_X:
643 case BPF_S_JMP_JGE_X:
644 case BPF_S_JMP_JEQ_X:
645 seen |= SEEN_XREG;
646 EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
647 break;
648 case BPF_S_JMP_JSET_X:
649 seen |= SEEN_XREG;
650 EMIT2(0x85, 0xd8); /* test %ebx,%eax */
651 break;
652 case BPF_S_JMP_JEQ_K:
653 if (K == 0) {
654 EMIT2(0x85, 0xc0); /* test %eax,%eax */
655 break;
656 }
657 case BPF_S_JMP_JGT_K:
658 case BPF_S_JMP_JGE_K:
659 if (K <= 127)
660 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
661 else
662 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
663 break;
664 case BPF_S_JMP_JSET_K:
665 if (K <= 0xFF)
666 EMIT2(0xa8, K); /* test imm8,%al */
667 else if (!(K & 0xFFFF00FF))
668 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
669 else if (K <= 0xFFFF) {
670 EMIT2(0x66, 0xa9); /* test imm16,%ax */
671 EMIT(K, 2);
672 } else {
673 EMIT1_off32(0xa9, K); /* test imm32,%eax */
674 }
675 break;
676 }
677 if (filter[i].jt != 0) {
a03ffcf8
MK		 678 if (filter[i].jf && f_offset)
679 t_offset += is_near(f_offset) ? 2 : 5;
0a14842f
ED		 680 EMIT_COND_JMP(t_op, t_offset);
681 if (filter[i].jf)
682 EMIT_JMP(f_offset);
683 break;
684 }
685 EMIT_COND_JMP(f_op, f_offset);
686 break;
687 default:
688 /* hmm, too complex filter, give up with jit compiler */
689 goto out;
690 }
691 ilen = prog - temp;
692 if (image) {
693 if (unlikely(proglen + ilen > oldproglen)) {
694 pr_err("bpb_jit_compile fatal error\n");
695 kfree(addrs);
696 module_free(NULL, image);
697 return;
698 }
699 memcpy(image + proglen, temp, ilen);
700 }
701 proglen += ilen;
702 addrs[i] = proglen;
703 prog = temp;
704 }
705 /* last bpf instruction is always a RET :
706 * use it to give the cleanup instruction(s) addr
707 */
708 cleanup_addr = proglen - 1; /* ret */
d00a9dd2 709 if (seen_or_pass0)
0a14842f 710 cleanup_addr -= 1; /* leaveq */
d00a9dd2 711 if (seen_or_pass0 & SEEN_XREG)
0a14842f
ED		 712 cleanup_addr -= 4; /* mov -8(%rbp),%rbx */
713
714 if (image) {
d00a9dd2
ED		 715 if (proglen != oldproglen)
716 pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
0a14842f
ED		 717 break;
718 }
719 if (proglen == oldproglen) {
650c8496 720 image = module_alloc(proglen);
0a14842f
ED		 721 if (!image)
722 goto out;
723 }
724 oldproglen = proglen;
725 }
79617801 726
0a14842f 727 if (bpf_jit_enable > 1)
79617801 728 bpf_jit_dump(flen, proglen, pass, image);
0a14842f
ED		 729
730 if (image) {
0a14842f 731 bpf_flush_icache(image, image + proglen);
0a14842f
ED		 732 fp->bpf_func = (void *)image;
733 }
734out:
735 kfree(addrs);
736 return;
737}
738
0a14842f
ED		 739void bpf_jit_free(struct sk_filter *fp)
740{
650c8496
ED		 741 if (fp->bpf_func != sk_run_filter)
742 module_free(NULL, fp->bpf_func);
0a14842f 743}
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