aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/net/bpf_jit_comp.c
blob: 080f3f071bb05d46a79a6daa3f848073014b4928 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
/* bpf_jit_comp.c : BPF JIT compiler
 *
 * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
 * Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */
#include <linux/moduleloader.h>
#include <asm/cacheflush.h>
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <linux/random.h>

int bpf_jit_enable __read_mostly;

/*
 * assembly code in arch/x86/net/bpf_jit.S
 */
extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
extern u8 sk_load_byte_positive_offset[];
extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
extern u8 sk_load_byte_negative_offset[];

static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
{
	if (len == 1)
		*ptr = bytes;
	else if (len == 2)
		*(u16 *)ptr = bytes;
	else {
		*(u32 *)ptr = bytes;
		barrier();
	}
	return ptr + len;
}

#define EMIT(bytes, len)	do { prog = emit_code(prog, bytes, len); } while (0)

#define EMIT1(b1)		EMIT(b1, 1)
#define EMIT2(b1, b2)		EMIT((b1) + ((b2) << 8), 2)
#define EMIT3(b1, b2, b3)	EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
#define EMIT4(b1, b2, b3, b4)   EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
#define EMIT1_off32(b1, off) \
	do {EMIT1(b1); EMIT(off, 4); } while (0)
#define EMIT2_off32(b1, b2, off) \
	do {EMIT2(b1, b2); EMIT(off, 4); } while (0)
#define EMIT3_off32(b1, b2, b3, off) \
	do {EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
#define EMIT4_off32(b1, b2, b3, b4, off) \
	do {EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)

static inline bool is_imm8(int value)
{
	return value <= 127 && value >= -128;
}

static inline bool is_simm32(s64 value)
{
	return value == (s64) (s32) value;
}

/* mov A, X */
#define EMIT_mov(A, X) \
	do {if (A != X) \
		EMIT3(add_2mod(0x48, A, X), 0x89, add_2reg(0xC0, A, X)); \
	} while (0)

static int bpf_size_to_x86_bytes(int bpf_size)
{
	if (bpf_size == BPF_W)
		return 4;
	else if (bpf_size == BPF_H)
		return 2;
	else if (bpf_size == BPF_B)
		return 1;
	else if (bpf_size == BPF_DW)
		return 4; /* imm32 */
	else
		return 0;
}

/* list of x86 cond jumps opcodes (. + s8)
 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
 */
#define X86_JB  0x72
#define X86_JAE 0x73
#define X86_JE  0x74
#define X86_JNE 0x75
#define X86_JBE 0x76
#define X86_JA  0x77
#define X86_JGE 0x7D
#define X86_JG  0x7F

static inline void bpf_flush_icache(void *start, void *end)
{
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	smp_wmb();
	flush_icache_range((unsigned long)start, (unsigned long)end);
	set_fs(old_fs);
}

#define CHOOSE_LOAD_FUNC(K, func) \
	((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)

struct bpf_binary_header {
	unsigned int	pages;
	/* Note : for security reasons, bpf code will follow a randomly
	 * sized amount of int3 instructions
	 */
	u8		image[];
};

static struct bpf_binary_header *bpf_alloc_binary(unsigned int proglen,
						  u8 **image_ptr)
{
	unsigned int sz, hole;
	struct bpf_binary_header *header;

	/* Most of BPF filters are really small,
	 * but if some of them fill a page, allow at least
	 * 128 extra bytes to insert a random section of int3
	 */
	sz = round_up(proglen + sizeof(*header) + 128, PAGE_SIZE);
	header = module_alloc(sz);
	if (!header)
		return NULL;

	memset(header, 0xcc, sz); /* fill whole space with int3 instructions */

	header->pages = sz / PAGE_SIZE;
	hole = min(sz - (proglen + sizeof(*header)), PAGE_SIZE - sizeof(*header));

	/* insert a random number of int3 instructions before BPF code */
	*image_ptr = &header->image[prandom_u32() % hole];
	return header;
}

/* pick a register outside of BPF range for JIT internal work */
#define AUX_REG (MAX_BPF_REG + 1)

/* the following table maps BPF registers to x64 registers.
 * x64 register r12 is unused, since if used as base address register
 * in load/store instructions, it always needs an extra byte of encoding
 */
static const int reg2hex[] = {
	[BPF_REG_0] = 0,  /* rax */
	[BPF_REG_1] = 7,  /* rdi */
	[BPF_REG_2] = 6,  /* rsi */
	[BPF_REG_3] = 2,  /* rdx */
	[BPF_REG_4] = 1,  /* rcx */
	[BPF_REG_5] = 0,  /* r8 */
	[BPF_REG_6] = 3,  /* rbx callee saved */
	[BPF_REG_7] = 5,  /* r13 callee saved */
	[BPF_REG_8] = 6,  /* r14 callee saved */
	[BPF_REG_9] = 7,  /* r15 callee saved */
	[BPF_REG_FP] = 5, /* rbp readonly */
	[AUX_REG] = 3,    /* r11 temp register */
};

/* is_ereg() == true if BPF register 'reg' maps to x64 r8..r15
 * which need extra byte of encoding.
 * rax,rcx,...,rbp have simpler encoding
 */
static inline bool is_ereg(u32 reg)
{
	if (reg == BPF_REG_5 || reg == AUX_REG ||
	    (reg >= BPF_REG_7 && reg <= BPF_REG_9))
		return true;
	else
		return false;
}

/* add modifiers if 'reg' maps to x64 registers r8..r15 */
static inline u8 add_1mod(u8 byte, u32 reg)
{
	if (is_ereg(reg))
		byte |= 1;
	return byte;
}

static inline u8 add_2mod(u8 byte, u32 r1, u32 r2)
{
	if (is_ereg(r1))
		byte |= 1;
	if (is_ereg(r2))
		byte |= 4;
	return byte;
}

/* encode dest register 'a_reg' into x64 opcode 'byte' */
static inline u8 add_1reg(u8 byte, u32 a_reg)
{
	return byte + reg2hex[a_reg];
}

/* encode dest 'a_reg' and src 'x_reg' registers into x64 opcode 'byte' */
static inline u8 add_2reg(u8 byte, u32 a_reg, u32 x_reg)
{
	return byte + reg2hex[a_reg] + (reg2hex[x_reg] << 3);
}

struct jit_context {
	unsigned int cleanup_addr; /* epilogue code offset */
	bool seen_ld_abs;
};

static int do_jit(struct sk_filter *bpf_prog, int *addrs, u8 *image,
		  int oldproglen, struct jit_context *ctx)
{
	struct sock_filter_int *insn = bpf_prog->insnsi;
	int insn_cnt = bpf_prog->len;
	u8 temp[64];
	int i;
	int proglen = 0;
	u8 *prog = temp;
	int stacksize = MAX_BPF_STACK +
		32 /* space for rbx, r13, r14, r15 */ +
		8 /* space for skb_copy_bits() buffer */;

	EMIT1(0x55); /* push rbp */
	EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */

	/* sub rsp, stacksize */
	EMIT3_off32(0x48, 0x81, 0xEC, stacksize);

	/* all classic BPF filters use R6(rbx) save it */

	/* mov qword ptr [rbp-X],rbx */
	EMIT3_off32(0x48, 0x89, 0x9D, -stacksize);

	/* sk_convert_filter() maps classic BPF register X to R7 and uses R8
	 * as temporary, so all tcpdump filters need to spill/fill R7(r13) and
	 * R8(r14). R9(r15) spill could be made conditional, but there is only
	 * one 'bpf_error' return path out of helper functions inside bpf_jit.S
	 * The overhead of extra spill is negligible for any filter other
	 * than synthetic ones. Therefore not worth adding complexity.
	 */

	/* mov qword ptr [rbp-X],r13 */
	EMIT3_off32(0x4C, 0x89, 0xAD, -stacksize + 8);
	/* mov qword ptr [rbp-X],r14 */
	EMIT3_off32(0x4C, 0x89, 0xB5, -stacksize + 16);
	/* mov qword ptr [rbp-X],r15 */
	EMIT3_off32(0x4C, 0x89, 0xBD, -stacksize + 24);

	/* clear A and X registers */
	EMIT2(0x31, 0xc0); /* xor eax, eax */
	EMIT3(0x4D, 0x31, 0xED); /* xor r13, r13 */

	if (ctx->seen_ld_abs) {
		/* r9d : skb->len - skb->data_len (headlen)
		 * r10 : skb->data
		 */
		if (is_imm8(offsetof(struct sk_buff, len)))
			/* mov %r9d, off8(%rdi) */
			EMIT4(0x44, 0x8b, 0x4f,
			      offsetof(struct sk_buff, len));
		else
			/* mov %r9d, off32(%rdi) */
			EMIT3_off32(0x44, 0x8b, 0x8f,
				    offsetof(struct sk_buff, len));

		if (is_imm8(offsetof(struct sk_buff, data_len)))
			/* sub %r9d, off8(%rdi) */
			EMIT4(0x44, 0x2b, 0x4f,
			      offsetof(struct sk_buff, data_len));
		else
			EMIT3_off32(0x44, 0x2b, 0x8f,
				    offsetof(struct sk_buff, data_len));

		if (is_imm8(offsetof(struct sk_buff, data)))
			/* mov %r10, off8(%rdi) */
			EMIT4(0x4c, 0x8b, 0x57,
			      offsetof(struct sk_buff, data));
		else
			/* mov %r10, off32(%rdi) */
			EMIT3_off32(0x4c, 0x8b, 0x97,
				    offsetof(struct sk_buff, data));
	}

	for (i = 0; i < insn_cnt; i++, insn++) {
		const s32 K = insn->imm;
		u32 a_reg = insn->a_reg;
		u32 x_reg = insn->x_reg;
		u8 b1 = 0, b2 = 0, b3 = 0;
		s64 jmp_offset;
		u8 jmp_cond;
		int ilen;
		u8 *func;

		switch (insn->code) {
			/* ALU */
		case BPF_ALU | BPF_ADD | BPF_X:
		case BPF_ALU | BPF_SUB | BPF_X:
		case BPF_ALU | BPF_AND | BPF_X:
		case BPF_ALU | BPF_OR | BPF_X:
		case BPF_ALU | BPF_XOR | BPF_X:
		case BPF_ALU64 | BPF_ADD | BPF_X:
		case BPF_ALU64 | BPF_SUB | BPF_X:
		case BPF_ALU64 | BPF_AND | BPF_X:
		case BPF_ALU64 | BPF_OR | BPF_X:
		case BPF_ALU64 | BPF_XOR | BPF_X:
			switch (BPF_OP(insn->code)) {
			case BPF_ADD: b2 = 0x01; break;
			case BPF_SUB: b2 = 0x29; break;
			case BPF_AND: b2 = 0x21; break;
			case BPF_OR: b2 = 0x09; break;
			case BPF_XOR: b2 = 0x31; break;
			}
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_2mod(0x48, a_reg, x_reg));
			else if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT1(add_2mod(0x40, a_reg, x_reg));
			EMIT2(b2, add_2reg(0xC0, a_reg, x_reg));
			break;

			/* mov A, X */
		case BPF_ALU64 | BPF_MOV | BPF_X:
			EMIT_mov(a_reg, x_reg);
			break;

			/* mov32 A, X */
		case BPF_ALU | BPF_MOV | BPF_X:
			if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT1(add_2mod(0x40, a_reg, x_reg));
			EMIT2(0x89, add_2reg(0xC0, a_reg, x_reg));
			break;

			/* neg A */
		case BPF_ALU | BPF_NEG:
		case BPF_ALU64 | BPF_NEG:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, a_reg));
			else if (is_ereg(a_reg))
				EMIT1(add_1mod(0x40, a_reg));
			EMIT2(0xF7, add_1reg(0xD8, a_reg));
			break;

		case BPF_ALU | BPF_ADD | BPF_K:
		case BPF_ALU | BPF_SUB | BPF_K:
		case BPF_ALU | BPF_AND | BPF_K:
		case BPF_ALU | BPF_OR | BPF_K:
		case BPF_ALU | BPF_XOR | BPF_K:
		case BPF_ALU64 | BPF_ADD | BPF_K:
		case BPF_ALU64 | BPF_SUB | BPF_K:
		case BPF_ALU64 | BPF_AND | BPF_K:
		case BPF_ALU64 | BPF_OR | BPF_K:
		case BPF_ALU64 | BPF_XOR | BPF_K:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, a_reg));
			else if (is_ereg(a_reg))
				EMIT1(add_1mod(0x40, a_reg));

			switch (BPF_OP(insn->code)) {
			case BPF_ADD: b3 = 0xC0; break;
			case BPF_SUB: b3 = 0xE8; break;
			case BPF_AND: b3 = 0xE0; break;
			case BPF_OR: b3 = 0xC8; break;
			case BPF_XOR: b3 = 0xF0; break;
			}

			if (is_imm8(K))
				EMIT3(0x83, add_1reg(b3, a_reg), K);
			else
				EMIT2_off32(0x81, add_1reg(b3, a_reg), K);
			break;

		case BPF_ALU64 | BPF_MOV | BPF_K:
			/* optimization: if imm32 is positive,
			 * use 'mov eax, imm32' (which zero-extends imm32)
			 * to save 2 bytes
			 */
			if (K < 0) {
				/* 'mov rax, imm32' sign extends imm32 */
				b1 = add_1mod(0x48, a_reg);
				b2 = 0xC7;
				b3 = 0xC0;
				EMIT3_off32(b1, b2, add_1reg(b3, a_reg), K);
				break;
			}

		case BPF_ALU | BPF_MOV | BPF_K:
			/* mov %eax, imm32 */
			if (is_ereg(a_reg))
				EMIT1(add_1mod(0x40, a_reg));
			EMIT1_off32(add_1reg(0xB8, a_reg), K);
			break;

			/* A %= X, A /= X, A %= K, A /= K */
		case BPF_ALU | BPF_MOD | BPF_X:
		case BPF_ALU | BPF_DIV | BPF_X:
		case BPF_ALU | BPF_MOD | BPF_K:
		case BPF_ALU | BPF_DIV | BPF_K:
		case BPF_ALU64 | BPF_MOD | BPF_X:
		case BPF_ALU64 | BPF_DIV | BPF_X:
		case BPF_ALU64 | BPF_MOD | BPF_K:
		case BPF_ALU64 | BPF_DIV | BPF_K:
			EMIT1(0x50); /* push rax */
			EMIT1(0x52); /* push rdx */

			if (BPF_SRC(insn->code) == BPF_X)
				/* mov r11, X */
				EMIT_mov(AUX_REG, x_reg);
			else
				/* mov r11, K */
				EMIT3_off32(0x49, 0xC7, 0xC3, K);

			/* mov rax, A */
			EMIT_mov(BPF_REG_0, a_reg);

			/* xor edx, edx
			 * equivalent to 'xor rdx, rdx', but one byte less
			 */
			EMIT2(0x31, 0xd2);

			if (BPF_SRC(insn->code) == BPF_X) {
				/* if (X == 0) return 0 */

				/* cmp r11, 0 */
				EMIT4(0x49, 0x83, 0xFB, 0x00);

				/* jne .+9 (skip over pop, pop, xor and jmp) */
				EMIT2(X86_JNE, 1 + 1 + 2 + 5);
				EMIT1(0x5A); /* pop rdx */
				EMIT1(0x58); /* pop rax */
				EMIT2(0x31, 0xc0); /* xor eax, eax */

				/* jmp cleanup_addr
				 * addrs[i] - 11, because there are 11 bytes
				 * after this insn: div, mov, pop, pop, mov
				 */
				jmp_offset = ctx->cleanup_addr - (addrs[i] - 11);
				EMIT1_off32(0xE9, jmp_offset);
			}

			if (BPF_CLASS(insn->code) == BPF_ALU64)
				/* div r11 */
				EMIT3(0x49, 0xF7, 0xF3);
			else
				/* div r11d */
				EMIT3(0x41, 0xF7, 0xF3);

			if (BPF_OP(insn->code) == BPF_MOD)
				/* mov r11, rdx */
				EMIT3(0x49, 0x89, 0xD3);
			else
				/* mov r11, rax */
				EMIT3(0x49, 0x89, 0xC3);

			EMIT1(0x5A); /* pop rdx */
			EMIT1(0x58); /* pop rax */

			/* mov A, r11 */
			EMIT_mov(a_reg, AUX_REG);
			break;

		case BPF_ALU | BPF_MUL | BPF_K:
		case BPF_ALU | BPF_MUL | BPF_X:
		case BPF_ALU64 | BPF_MUL | BPF_K:
		case BPF_ALU64 | BPF_MUL | BPF_X:
			EMIT1(0x50); /* push rax */
			EMIT1(0x52); /* push rdx */

			/* mov r11, A */
			EMIT_mov(AUX_REG, a_reg);

			if (BPF_SRC(insn->code) == BPF_X)
				/* mov rax, X */
				EMIT_mov(BPF_REG_0, x_reg);
			else
				/* mov rax, K */
				EMIT3_off32(0x48, 0xC7, 0xC0, K);

			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, AUX_REG));
			else if (is_ereg(AUX_REG))
				EMIT1(add_1mod(0x40, AUX_REG));
			/* mul(q) r11 */
			EMIT2(0xF7, add_1reg(0xE0, AUX_REG));

			/* mov r11, rax */
			EMIT_mov(AUX_REG, BPF_REG_0);

			EMIT1(0x5A); /* pop rdx */
			EMIT1(0x58); /* pop rax */

			/* mov A, r11 */
			EMIT_mov(a_reg, AUX_REG);
			break;

			/* shifts */
		case BPF_ALU | BPF_LSH | BPF_K:
		case BPF_ALU | BPF_RSH | BPF_K:
		case BPF_ALU | BPF_ARSH | BPF_K:
		case BPF_ALU64 | BPF_LSH | BPF_K:
		case BPF_ALU64 | BPF_RSH | BPF_K:
		case BPF_ALU64 | BPF_ARSH | BPF_K:
			if (BPF_CLASS(insn->code) == BPF_ALU64)
				EMIT1(add_1mod(0x48, a_reg));
			else if (is_ereg(a_reg))
				EMIT1(add_1mod(0x40, a_reg));

			switch (BPF_OP(insn->code)) {
			case BPF_LSH: b3 = 0xE0; break;
			case BPF_RSH: b3 = 0xE8; break;
			case BPF_ARSH: b3 = 0xF8; break;
			}
			EMIT3(0xC1, add_1reg(b3, a_reg), K);
			break;

		case BPF_ALU | BPF_END | BPF_FROM_BE:
			switch (K) {
			case 16:
				/* emit 'ror %ax, 8' to swap lower 2 bytes */
				EMIT1(0x66);
				if (is_ereg(a_reg))
					EMIT1(0x41);
				EMIT3(0xC1, add_1reg(0xC8, a_reg), 8);
				break;
			case 32:
				/* emit 'bswap eax' to swap lower 4 bytes */
				if (is_ereg(a_reg))
					EMIT2(0x41, 0x0F);
				else
					EMIT1(0x0F);
				EMIT1(add_1reg(0xC8, a_reg));
				break;
			case 64:
				/* emit 'bswap rax' to swap 8 bytes */
				EMIT3(add_1mod(0x48, a_reg), 0x0F,
				      add_1reg(0xC8, a_reg));
				break;
			}
			break;

		case BPF_ALU | BPF_END | BPF_FROM_LE:
			break;

			/* ST: *(u8*)(a_reg + off) = imm */
		case BPF_ST | BPF_MEM | BPF_B:
			if (is_ereg(a_reg))
				EMIT2(0x41, 0xC6);
			else
				EMIT1(0xC6);
			goto st;
		case BPF_ST | BPF_MEM | BPF_H:
			if (is_ereg(a_reg))
				EMIT3(0x66, 0x41, 0xC7);
			else
				EMIT2(0x66, 0xC7);
			goto st;
		case BPF_ST | BPF_MEM | BPF_W:
			if (is_ereg(a_reg))
				EMIT2(0x41, 0xC7);
			else
				EMIT1(0xC7);
			goto st;
		case BPF_ST | BPF_MEM | BPF_DW:
			EMIT2(add_1mod(0x48, a_reg), 0xC7);

st:			if (is_imm8(insn->off))
				EMIT2(add_1reg(0x40, a_reg), insn->off);
			else
				EMIT1_off32(add_1reg(0x80, a_reg), insn->off);

			EMIT(K, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
			break;

			/* STX: *(u8*)(a_reg + off) = x_reg */
		case BPF_STX | BPF_MEM | BPF_B:
			/* emit 'mov byte ptr [rax + off], al' */
			if (is_ereg(a_reg) || is_ereg(x_reg) ||
			    /* have to add extra byte for x86 SIL, DIL regs */
			    x_reg == BPF_REG_1 || x_reg == BPF_REG_2)
				EMIT2(add_2mod(0x40, a_reg, x_reg), 0x88);
			else
				EMIT1(0x88);
			goto stx;
		case BPF_STX | BPF_MEM | BPF_H:
			if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT3(0x66, add_2mod(0x40, a_reg, x_reg), 0x89);
			else
				EMIT2(0x66, 0x89);
			goto stx;
		case BPF_STX | BPF_MEM | BPF_W:
			if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT2(add_2mod(0x40, a_reg, x_reg), 0x89);
			else
				EMIT1(0x89);
			goto stx;
		case BPF_STX | BPF_MEM | BPF_DW:
			EMIT2(add_2mod(0x48, a_reg, x_reg), 0x89);
stx:			if (is_imm8(insn->off))
				EMIT2(add_2reg(0x40, a_reg, x_reg), insn->off);
			else
				EMIT1_off32(add_2reg(0x80, a_reg, x_reg),
					    insn->off);
			break;

			/* LDX: a_reg = *(u8*)(x_reg + off) */
		case BPF_LDX | BPF_MEM | BPF_B:
			/* emit 'movzx rax, byte ptr [rax + off]' */
			EMIT3(add_2mod(0x48, x_reg, a_reg), 0x0F, 0xB6);
			goto ldx;
		case BPF_LDX | BPF_MEM | BPF_H:
			/* emit 'movzx rax, word ptr [rax + off]' */
			EMIT3(add_2mod(0x48, x_reg, a_reg), 0x0F, 0xB7);
			goto ldx;
		case BPF_LDX | BPF_MEM | BPF_W:
			/* emit 'mov eax, dword ptr [rax+0x14]' */
			if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT2(add_2mod(0x40, x_reg, a_reg), 0x8B);
			else
				EMIT1(0x8B);
			goto ldx;
		case BPF_LDX | BPF_MEM | BPF_DW:
			/* emit 'mov rax, qword ptr [rax+0x14]' */
			EMIT2(add_2mod(0x48, x_reg, a_reg), 0x8B);
ldx:			/* if insn->off == 0 we can save one extra byte, but
			 * special case of x86 r13 which always needs an offset
			 * is not worth the hassle
			 */
			if (is_imm8(insn->off))
				EMIT2(add_2reg(0x40, x_reg, a_reg), insn->off);
			else
				EMIT1_off32(add_2reg(0x80, x_reg, a_reg),
					    insn->off);
			break;

			/* STX XADD: lock *(u32*)(a_reg + off) += x_reg */
		case BPF_STX | BPF_XADD | BPF_W:
			/* emit 'lock add dword ptr [rax + off], eax' */
			if (is_ereg(a_reg) || is_ereg(x_reg))
				EMIT3(0xF0, add_2mod(0x40, a_reg, x_reg), 0x01);
			else
				EMIT2(0xF0, 0x01);
			goto xadd;
		case BPF_STX | BPF_XADD | BPF_DW:
			EMIT3(0xF0, add_2mod(0x48, a_reg, x_reg), 0x01);
xadd:			if (is_imm8(insn->off))
				EMIT2(add_2reg(0x40, a_reg, x_reg), insn->off);
			else
				EMIT1_off32(add_2reg(0x80, a_reg, x_reg),
					    insn->off);
			break;

			/* call */
		case BPF_JMP | BPF_CALL:
			func = (u8 *) __bpf_call_base + K;
			jmp_offset = func - (image + addrs[i]);
			if (ctx->seen_ld_abs) {
				EMIT2(0x41, 0x52); /* push %r10 */
				EMIT2(0x41, 0x51); /* push %r9 */
				/* need to adjust jmp offset, since
				 * pop %r9, pop %r10 take 4 bytes after call insn
				 */
				jmp_offset += 4;
			}
			if (!K || !is_simm32(jmp_offset)) {
				pr_err("unsupported bpf func %d addr %p image %p\n",
				       K, func, image);
				return -EINVAL;
			}
			EMIT1_off32(0xE8, jmp_offset);
			if (ctx->seen_ld_abs) {
				EMIT2(0x41, 0x59); /* pop %r9 */
				EMIT2(0x41, 0x5A); /* pop %r10 */
			}
			break;

			/* cond jump */
		case BPF_JMP | BPF_JEQ | BPF_X:
		case BPF_JMP | BPF_JNE | BPF_X:
		case BPF_JMP | BPF_JGT | BPF_X:
		case BPF_JMP | BPF_JGE | BPF_X:
		case BPF_JMP | BPF_JSGT | BPF_X:
		case BPF_JMP | BPF_JSGE | BPF_X:
			/* cmp a_reg, x_reg */
			EMIT3(add_2mod(0x48, a_reg, x_reg), 0x39,
			      add_2reg(0xC0, a_reg, x_reg));
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JSET | BPF_X:
			/* test a_reg, x_reg */
			EMIT3(add_2mod(0x48, a_reg, x_reg), 0x85,
			      add_2reg(0xC0, a_reg, x_reg));
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JSET | BPF_K:
			/* test a_reg, imm32 */
			EMIT1(add_1mod(0x48, a_reg));
			EMIT2_off32(0xF7, add_1reg(0xC0, a_reg), K);
			goto emit_cond_jmp;

		case BPF_JMP | BPF_JEQ | BPF_K:
		case BPF_JMP | BPF_JNE | BPF_K:
		case BPF_JMP | BPF_JGT | BPF_K:
		case BPF_JMP | BPF_JGE | BPF_K:
		case BPF_JMP | BPF_JSGT | BPF_K:
		case BPF_JMP | BPF_JSGE | BPF_K:
			/* cmp a_reg, imm8/32 */
			EMIT1(add_1mod(0x48, a_reg));

			if (is_imm8(K))
				EMIT3(0x83, add_1reg(0xF8, a_reg), K);
			else
				EMIT2_off32(0x81, add_1reg(0xF8, a_reg), K);

emit_cond_jmp:		/* convert BPF opcode to x86 */
			switch (BPF_OP(insn->code)) {
			case BPF_JEQ:
				jmp_cond = X86_JE;
				break;
			case BPF_JSET:
			case BPF_JNE:
				jmp_cond = X86_JNE;
				break;
			case BPF_JGT:
				/* GT is unsigned '>', JA in x86 */
				jmp_cond = X86_JA;
				break;
			case BPF_JGE:
				/* GE is unsigned '>=', JAE in x86 */
				jmp_cond = X86_JAE;
				break;
			case BPF_JSGT:
				/* signed '>', GT in x86 */
				jmp_cond = X86_JG;
				break;
			case BPF_JSGE:
				/* signed '>=', GE in x86 */
				jmp_cond = X86_JGE;
				break;
			default: /* to silence gcc warning */
				return -EFAULT;
			}
			jmp_offset = addrs[i + insn->off] - addrs[i];
			if (is_imm8(jmp_offset)) {
				EMIT2(jmp_cond, jmp_offset);
			} else if (is_simm32(jmp_offset)) {
				EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
			} else {
				pr_err("cond_jmp gen bug %llx\n", jmp_offset);
				return -EFAULT;
			}

			break;

		case BPF_JMP | BPF_JA:
			jmp_offset = addrs[i + insn->off] - addrs[i];
			if (!jmp_offset)
				/* optimize out nop jumps */
				break;
emit_jmp:
			if (is_imm8(jmp_offset)) {
				EMIT2(0xEB, jmp_offset);
			} else if (is_simm32(jmp_offset)) {
				EMIT1_off32(0xE9, jmp_offset);
			} else {
				pr_err("jmp gen bug %llx\n", jmp_offset);
				return -EFAULT;
			}
			break;

		case BPF_LD | BPF_IND | BPF_W:
			func = sk_load_word;
			goto common_load;
		case BPF_LD | BPF_ABS | BPF_W:
			func = CHOOSE_LOAD_FUNC(K, sk_load_word);
common_load:		ctx->seen_ld_abs = true;
			jmp_offset = func - (image + addrs[i]);
			if (!func || !is_simm32(jmp_offset)) {
				pr_err("unsupported bpf func %d addr %p image %p\n",
				       K, func, image);
				return -EINVAL;
			}
			if (BPF_MODE(insn->code) == BPF_ABS) {
				/* mov %esi, imm32 */
				EMIT1_off32(0xBE, K);
			} else {
				/* mov %rsi, x_reg */
				EMIT_mov(BPF_REG_2, x_reg);
				if (K) {
					if (is_imm8(K))
						/* add %esi, imm8 */
						EMIT3(0x83, 0xC6, K);
					else
						/* add %esi, imm32 */
						EMIT2_off32(0x81, 0xC6, K);
				}
			}
			/* skb pointer is in R6 (%rbx), it will be copied into
			 * %rdi if skb_copy_bits() call is necessary.
			 * sk_load_* helpers also use %r10 and %r9d.
			 * See bpf_jit.S
			 */
			EMIT1_off32(0xE8, jmp_offset); /* call */
			break;

		case BPF_LD | BPF_IND | BPF_H:
			func = sk_load_half;
			goto common_load;
		case BPF_LD | BPF_ABS | BPF_H:
			func = CHOOSE_LOAD_FUNC(K, sk_load_half);
			goto common_load;
		case BPF_LD | BPF_IND | BPF_B:
			func = sk_load_byte;
			goto common_load;
		case BPF_LD | BPF_ABS | BPF_B:
			func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
			goto common_load;

		case BPF_JMP | BPF_EXIT:
			if (i != insn_cnt - 1) {
				jmp_offset = ctx->cleanup_addr - addrs[i];
				goto emit_jmp;
			}
			/* update cleanup_addr */
			ctx->cleanup_addr = proglen;
			/* mov rbx, qword ptr [rbp-X] */
			EMIT3_off32(0x48, 0x8B, 0x9D, -stacksize);
			/* mov r13, qword ptr [rbp-X] */
			EMIT3_off32(0x4C, 0x8B, 0xAD, -stacksize + 8);
			/* mov r14, qword ptr [rbp-X] */
			EMIT3_off32(0x4C, 0x8B, 0xB5, -stacksize + 16);
			/* mov r15, qword ptr [rbp-X] */
			EMIT3_off32(0x4C, 0x8B, 0xBD, -stacksize + 24);

			EMIT1(0xC9); /* leave */
			EMIT1(0xC3); /* ret */
			break;

		default:
			/* By design x64 JIT should support all BPF instructions
			 * This error will be seen if new instruction was added
			 * to interpreter, but not to JIT
			 * or if there is junk in sk_filter
			 */
			pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
			return -EINVAL;
		}

		ilen = prog - temp;
		if (image) {
			if (unlikely(proglen + ilen > oldproglen)) {
				pr_err("bpf_jit_compile fatal error\n");
				return -EFAULT;
			}
			memcpy(image + proglen, temp, ilen);
		}
		proglen += ilen;
		addrs[i] = proglen;
		prog = temp;
	}
	return proglen;
}

void bpf_jit_compile(struct sk_filter *prog)
{
}

void bpf_int_jit_compile(struct sk_filter *prog)
{
	struct bpf_binary_header *header = NULL;
	int proglen, oldproglen = 0;
	struct jit_context ctx = {};
	u8 *image = NULL;
	int *addrs;
	int pass;
	int i;

	if (!bpf_jit_enable)
		return;

	if (!prog || !prog->len)
		return;

	addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
	if (!addrs)
		return;

	/* Before first pass, make a rough estimation of addrs[]
	 * each bpf instruction is translated to less than 64 bytes
	 */
	for (proglen = 0, i = 0; i < prog->len; i++) {
		proglen += 64;
		addrs[i] = proglen;
	}
	ctx.cleanup_addr = proglen;

	for (pass = 0; pass < 10; pass++) {
		proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
		if (proglen <= 0) {
			image = NULL;
			if (header)
				module_free(NULL, header);
			goto out;
		}
		if (image) {
			if (proglen != oldproglen)
				pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
				       proglen, oldproglen);
			break;
		}
		if (proglen == oldproglen) {
			header = bpf_alloc_binary(proglen, &image);
			if (!header)
				goto out;
		}
		oldproglen = proglen;
	}

	if (bpf_jit_enable > 1)
		bpf_jit_dump(prog->len, proglen, 0, image);

	if (image) {
		bpf_flush_icache(header, image + proglen);
		set_memory_ro((unsigned long)header, header->pages);
		prog->bpf_func = (void *)image;
		prog->jited = 1;
	}
out:
	kfree(addrs);
}

static void bpf_jit_free_deferred(struct work_struct *work)
{
	struct sk_filter *fp = container_of(work, struct sk_filter, work);
	unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
	struct bpf_binary_header *header = (void *)addr;

	set_memory_rw(addr, header->pages);
	module_free(NULL, header);
	kfree(fp);
}

void bpf_jit_free(struct sk_filter *fp)
{
	if (fp->jited) {
		INIT_WORK(&fp->work, bpf_jit_free_deferred);
		schedule_work(&fp->work);
	} else {
		kfree(fp);
	}
}