2 * BPF Jit compiler for s390.
4 * Copyright IBM Corp. 2012
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 #include <linux/moduleloader.h>
9 #include <linux/netdevice.h>
10 #include <linux/if_vlan.h>
11 #include <linux/filter.h>
12 #include <linux/random.h>
13 #include <linux/init.h>
14 #include <asm/cacheflush.h>
15 #include <asm/facility.h>
21 * %r3 = offset parameter
22 * %r4 = scratch register / length parameter
23 * %r5 = BPF A accumulator
24 * %r8 = return address
25 * %r9 = save register for skb pointer
27 * %r11 = skb->len - skb->data_len (headlen)
28 * %r12 = BPF X accumulator
29 * %r13 = literal pool pointer
30 * 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
32 int bpf_jit_enable __read_mostly;
35 * assembly code in arch/x86/net/bpf_jit.S
37 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
38 extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
50 unsigned int off_load_word;
51 unsigned int off_load_half;
52 unsigned int off_load_byte;
53 unsigned int off_load_bmsh;
54 unsigned int off_load_iword;
55 unsigned int off_load_ihalf;
56 unsigned int off_load_ibyte;
59 #define BPF_SIZE_MAX 4096 /* Max size for program */
61 #define SEEN_DATAREF 1 /* might call external helpers */
62 #define SEEN_XREG 2 /* ebx is used */
63 #define SEEN_MEM 4 /* use mem[] for temporary storage */
64 #define SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */
65 #define SEEN_LITERAL 16 /* code uses literals */
66 #define SEEN_LOAD_WORD 32 /* code uses sk_load_word */
67 #define SEEN_LOAD_HALF 64 /* code uses sk_load_half */
68 #define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */
69 #define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */
70 #define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */
71 #define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */
72 #define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */
76 if (jit->prg + 2 <= jit->mid) \
77 *(u16 *) jit->prg = op; \
83 if (jit->prg + 4 <= jit->mid) \
84 *(u32 *) jit->prg = op; \
88 #define EMIT4_DISP(op, disp) \
90 unsigned int __disp = (disp) & 0xfff; \
94 #define EMIT4_IMM(op, imm) \
96 unsigned int __imm = (imm) & 0xffff; \
100 #define EMIT4_PCREL(op, pcrel) \
102 long __pcrel = ((pcrel) >> 1) & 0xffff; \
103 EMIT4(op | __pcrel); \
106 #define EMIT6(op1, op2) \
108 if (jit->prg + 6 <= jit->mid) { \
109 *(u32 *) jit->prg = op1; \
110 *(u16 *) (jit->prg + 4) = op2; \
115 #define EMIT6_DISP(op1, op2, disp) \
117 unsigned int __disp = (disp) & 0xfff; \
118 EMIT6(op1 | __disp, op2); \
121 #define EMIT6_IMM(op, imm) \
123 unsigned int __imm = (imm); \
124 EMIT6(op | (__imm >> 16), __imm & 0xffff); \
127 #define EMIT_CONST(val) \
130 ret = (unsigned int) (jit->lit - jit->base_ip); \
131 jit->seen |= SEEN_LITERAL; \
132 if (jit->lit + 4 <= jit->end) \
133 *(u32 *) jit->lit = val; \
138 #define EMIT_FN_CONST(bit, fn) \
141 ret = (unsigned int) (jit->lit - jit->base_ip); \
142 if (jit->seen & bit) { \
143 jit->seen |= SEEN_LITERAL; \
144 if (jit->lit + 8 <= jit->end) \
145 *(void **) jit->lit = fn; \
151 static void bpf_jit_prologue(struct bpf_jit *jit)
153 /* Save registers and create stack frame if necessary */
154 if (jit->seen & SEEN_DATAREF) {
155 /* stmg %r8,%r15,88(%r15) */
156 EMIT6(0xeb8ff058, 0x0024);
159 /* aghi %r15,<offset> */
160 EMIT4_IMM(0xa7fb0000, (jit->seen & SEEN_MEM) ? -112 : -80);
161 /* stg %r14,152(%r15) */
162 EMIT6(0xe3e0f098, 0x0024);
163 } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
164 /* stmg %r12,%r13,120(%r15) */
165 EMIT6(0xebcdf078, 0x0024);
166 else if (jit->seen & SEEN_XREG)
167 /* stg %r12,120(%r15) */
168 EMIT6(0xe3c0f078, 0x0024);
169 else if (jit->seen & SEEN_LITERAL)
170 /* stg %r13,128(%r15) */
171 EMIT6(0xe3d0f080, 0x0024);
173 /* Setup literal pool */
174 if (jit->seen & SEEN_LITERAL) {
177 jit->base_ip = jit->prg;
179 jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
180 jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
181 jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
182 jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
183 jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
184 jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
185 jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
187 /* Filter needs to access skb data */
188 if (jit->seen & SEEN_DATAREF) {
189 /* l %r11,<len>(%r2) */
190 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
191 /* s %r11,<data_len>(%r2) */
192 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
193 /* lg %r10,<data>(%r2) */
194 EMIT6_DISP(0xe3a02000, 0x0004,
195 offsetof(struct sk_buff, data));
199 static void bpf_jit_epilogue(struct bpf_jit *jit)
202 if (jit->seen & SEEN_RET0) {
203 jit->ret0_ip = jit->prg;
207 jit->exit_ip = jit->prg;
208 /* Restore registers */
209 if (jit->seen & SEEN_DATAREF)
210 /* lmg %r8,%r15,<offset>(%r15) */
211 EMIT6_DISP(0xeb8ff000, 0x0004,
212 (jit->seen & SEEN_MEM) ? 200 : 168);
213 else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
214 /* lmg %r12,%r13,120(%r15) */
215 EMIT6(0xebcdf078, 0x0004);
216 else if (jit->seen & SEEN_XREG)
217 /* lg %r12,120(%r15) */
218 EMIT6(0xe3c0f078, 0x0004);
219 else if (jit->seen & SEEN_LITERAL)
220 /* lg %r13,128(%r15) */
221 EMIT6(0xe3d0f080, 0x0004);
226 /* Helper to find the offset of pkt_type in sk_buff
227 * Make sure its still a 3bit field starting at the MSBs within a byte.
229 #define PKT_TYPE_MAX 0xe0
230 static int pkt_type_offset;
232 static int __init bpf_pkt_type_offset_init(void)
234 struct sk_buff skb_probe = {
237 char *ct = (char *)&skb_probe;
240 pkt_type_offset = -1;
241 for (off = 0; off < sizeof(struct sk_buff); off++) {
244 if (ct[off] == PKT_TYPE_MAX)
245 pkt_type_offset = off;
247 /* Found non matching bit pattern, fix needed. */
249 pkt_type_offset = -1;
255 device_initcall(bpf_pkt_type_offset_init);
258 * make sure we dont leak kernel information to user
260 static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
262 /* Clear temporary memory if (seen & SEEN_MEM) */
263 if (jit->seen & SEEN_MEM)
264 /* xc 0(64,%r15),0(%r15) */
265 EMIT6(0xd73ff000, 0xf000);
266 /* Clear X if (seen & SEEN_XREG) */
267 if (jit->seen & SEEN_XREG)
270 /* Clear A if the first register does not set it. */
271 switch (filter[0].code) {
282 case BPF_S_ANC_PROTOCOL:
283 case BPF_S_ANC_PKTTYPE:
284 case BPF_S_ANC_IFINDEX:
286 case BPF_S_ANC_QUEUE:
287 case BPF_S_ANC_HATYPE:
288 case BPF_S_ANC_RXHASH:
290 case BPF_S_ANC_VLAN_TAG:
291 case BPF_S_ANC_VLAN_TAG_PRESENT:
293 /* first instruction sets A register */
301 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
302 unsigned int *addrs, int i, int last)
309 switch (filter->code) {
310 case BPF_S_ALU_ADD_X: /* A += X */
311 jit->seen |= SEEN_XREG;
315 case BPF_S_ALU_ADD_K: /* A += K */
320 EMIT4_IMM(0xa75a0000, K);
321 else if (test_facility(21))
323 EMIT6_IMM(0xc25b0000, K);
325 /* a %r5,<d(K)>(%r13) */
326 EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
328 case BPF_S_ALU_SUB_X: /* A -= X */
329 jit->seen |= SEEN_XREG;
333 case BPF_S_ALU_SUB_K: /* A -= K */
338 EMIT4_IMM(0xa75a0000, -K);
339 else if (test_facility(21))
341 EMIT6_IMM(0xc25b0000, -K);
343 /* s %r5,<d(K)>(%r13) */
344 EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
346 case BPF_S_ALU_MUL_X: /* A *= X */
347 jit->seen |= SEEN_XREG;
351 case BPF_S_ALU_MUL_K: /* A *= K */
354 EMIT4_IMM(0xa75c0000, K);
355 else if (test_facility(34))
357 EMIT6_IMM(0xc2510000, K);
359 /* ms %r5,<d(K)>(%r13) */
360 EMIT4_DISP(0x7150d000, EMIT_CONST(K));
362 case BPF_S_ALU_DIV_X: /* A /= X */
363 jit->seen |= SEEN_XREG | SEEN_RET0;
367 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
373 case BPF_S_ALU_DIV_K: /* A /= K */
378 /* dl %r4,<d(K)>(%r13) */
379 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
381 case BPF_S_ALU_MOD_X: /* A %= X */
382 jit->seen |= SEEN_XREG | SEEN_RET0;
386 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
394 case BPF_S_ALU_MOD_K: /* A %= K */
402 /* dl %r4,<d(K)>(%r13) */
403 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
407 case BPF_S_ALU_AND_X: /* A &= X */
408 jit->seen |= SEEN_XREG;
412 case BPF_S_ALU_AND_K: /* A &= K */
413 if (test_facility(21))
415 EMIT6_IMM(0xc05b0000, K);
417 /* n %r5,<d(K)>(%r13) */
418 EMIT4_DISP(0x5450d000, EMIT_CONST(K));
420 case BPF_S_ALU_OR_X: /* A |= X */
421 jit->seen |= SEEN_XREG;
425 case BPF_S_ALU_OR_K: /* A |= K */
426 if (test_facility(21))
428 EMIT6_IMM(0xc05d0000, K);
430 /* o %r5,<d(K)>(%r13) */
431 EMIT4_DISP(0x5650d000, EMIT_CONST(K));
433 case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
434 case BPF_S_ALU_XOR_X:
435 jit->seen |= SEEN_XREG;
439 case BPF_S_ALU_XOR_K: /* A ^= K */
442 /* x %r5,<d(K)>(%r13) */
443 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
445 case BPF_S_ALU_LSH_X: /* A <<= X; */
446 jit->seen |= SEEN_XREG;
447 /* sll %r5,0(%r12) */
450 case BPF_S_ALU_LSH_K: /* A <<= K */
454 EMIT4_DISP(0x89500000, K);
456 case BPF_S_ALU_RSH_X: /* A >>= X; */
457 jit->seen |= SEEN_XREG;
458 /* srl %r5,0(%r12) */
461 case BPF_S_ALU_RSH_K: /* A >>= K; */
465 EMIT4_DISP(0x88500000, K);
467 case BPF_S_ALU_NEG: /* A = -A */
471 case BPF_S_JMP_JA: /* ip += K */
472 offset = addrs[i + K] + jit->start - jit->prg;
473 EMIT4_PCREL(0xa7f40000, offset);
475 case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
476 mask = 0x200000; /* jh */
478 case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
479 mask = 0xa00000; /* jhe */
481 case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
482 mask = 0x800000; /* je */
483 kbranch: /* Emit compare if the branch targets are different */
484 if (filter->jt != filter->jf) {
487 EMIT4_IMM(0xa75e0000, K);
488 else if (test_facility(21))
490 EMIT6_IMM(0xc25f0000, K);
492 /* c %r5,<d(K)>(%r13) */
493 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
495 branch: if (filter->jt == filter->jf) {
499 offset = addrs[i + filter->jt] + jit->start - jit->prg;
500 EMIT4_PCREL(0xa7f40000, offset);
503 if (filter->jt != 0) {
504 /* brc <mask>,<jt> */
505 offset = addrs[i + filter->jt] + jit->start - jit->prg;
506 EMIT4_PCREL(0xa7040000 | mask, offset);
508 if (filter->jf != 0) {
509 /* brc <mask^15>,<jf> */
510 offset = addrs[i + filter->jf] + jit->start - jit->prg;
511 EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
514 case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
515 mask = 0x700000; /* jnz */
516 /* Emit test if the branch targets are different */
517 if (filter->jt != filter->jf) {
521 /* n %r4,<d(K)>(%r13) */
522 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
525 EMIT4_IMM(0xa7510000, K);
528 case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
529 mask = 0x200000; /* jh */
531 case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
532 mask = 0xa00000; /* jhe */
534 case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
535 mask = 0x800000; /* je */
536 xbranch: /* Emit compare if the branch targets are different */
537 if (filter->jt != filter->jf) {
538 jit->seen |= SEEN_XREG;
543 case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
544 mask = 0x700000; /* jnz */
545 /* Emit test if the branch targets are different */
546 if (filter->jt != filter->jf) {
547 jit->seen |= SEEN_XREG;
554 case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
555 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
556 offset = jit->off_load_word;
558 case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
559 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
560 offset = jit->off_load_half;
562 case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
563 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
564 offset = jit->off_load_byte;
565 load_abs: if ((int) K < 0)
567 call_fn: /* lg %r1,<d(function)>(%r13) */
568 EMIT6_DISP(0xe310d000, 0x0004, offset);
569 /* l %r3,<d(K)>(%r13) */
570 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
574 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
576 case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
577 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
578 offset = jit->off_load_iword;
580 case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
581 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
582 offset = jit->off_load_ihalf;
584 case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
585 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
586 offset = jit->off_load_ibyte;
588 case BPF_S_LDX_B_MSH:
589 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
590 jit->seen |= SEEN_RET0;
593 EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
596 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
597 offset = jit->off_load_bmsh;
599 case BPF_S_LD_W_LEN: /* A = skb->len; */
600 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
601 /* l %r5,<d(len)>(%r2) */
602 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
604 case BPF_S_LDX_W_LEN: /* X = skb->len; */
605 jit->seen |= SEEN_XREG;
606 /* l %r12,<d(len)>(%r2) */
607 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
609 case BPF_S_LD_IMM: /* A = K */
612 EMIT4_IMM(0xa7580000, K);
613 else if (test_facility(21))
615 EMIT6_IMM(0xc05f0000, K);
617 /* l %r5,<d(K)>(%r13) */
618 EMIT4_DISP(0x5850d000, EMIT_CONST(K));
620 case BPF_S_LDX_IMM: /* X = K */
621 jit->seen |= SEEN_XREG;
624 EMIT4_IMM(0xa7c80000, K);
625 else if (test_facility(21))
627 EMIT6_IMM(0xc0cf0000, K);
629 /* l %r12,<d(K)>(%r13) */
630 EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
632 case BPF_S_LD_MEM: /* A = mem[K] */
633 jit->seen |= SEEN_MEM;
634 /* l %r5,<K>(%r15) */
635 EMIT4_DISP(0x5850f000,
636 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
638 case BPF_S_LDX_MEM: /* X = mem[K] */
639 jit->seen |= SEEN_XREG | SEEN_MEM;
640 /* l %r12,<K>(%r15) */
641 EMIT4_DISP(0x58c0f000,
642 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
644 case BPF_S_MISC_TAX: /* X = A */
645 jit->seen |= SEEN_XREG;
649 case BPF_S_MISC_TXA: /* A = X */
650 jit->seen |= SEEN_XREG;
656 jit->seen |= SEEN_RET0;
660 EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
664 EMIT4_IMM(0xa7290000, K);
666 /* llgf %r2,<K>(%r13) */
667 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
669 if (last && !(jit->seen & SEEN_RET0))
671 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
678 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
680 case BPF_S_ST: /* mem[K] = A */
681 jit->seen |= SEEN_MEM;
682 /* st %r5,<K>(%r15) */
683 EMIT4_DISP(0x5050f000,
684 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
686 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
687 jit->seen |= SEEN_XREG | SEEN_MEM;
688 /* st %r12,<K>(%r15) */
689 EMIT4_DISP(0x50c0f000,
690 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
692 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
693 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
696 /* icm %r5,3,<d(protocol)>(%r2) */
697 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
699 case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
700 * A = skb->dev->ifindex */
701 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
702 jit->seen |= SEEN_RET0;
703 /* lg %r1,<d(dev)>(%r2) */
704 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
708 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
709 /* l %r5,<d(ifindex)>(%r1) */
710 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
712 case BPF_S_ANC_MARK: /* A = skb->mark */
713 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
714 /* l %r5,<d(mark)>(%r2) */
715 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
717 case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
718 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
721 /* icm %r5,3,<d(queue_mapping)>(%r2) */
722 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
724 case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0;
725 * A = skb->dev->type */
726 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
727 jit->seen |= SEEN_RET0;
728 /* lg %r1,<d(dev)>(%r2) */
729 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
733 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
736 /* icm %r5,3,<d(type)>(%r1) */
737 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
739 case BPF_S_ANC_RXHASH: /* A = skb->hash */
740 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
741 /* l %r5,<d(hash)>(%r2) */
742 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, hash));
744 case BPF_S_ANC_VLAN_TAG:
745 case BPF_S_ANC_VLAN_TAG_PRESENT:
746 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
747 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
750 /* icm %r5,3,<d(vlan_tci)>(%r2) */
751 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
752 if (filter->code == BPF_S_ANC_VLAN_TAG) {
753 /* nill %r5,0xefff */
754 EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
756 /* nill %r5,0x1000 */
757 EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
759 EMIT4_DISP(0x88500000, 12);
762 case BPF_S_ANC_PKTTYPE:
763 if (pkt_type_offset < 0)
767 /* ic %r5,<d(pkt_type_offset)>(%r2) */
768 EMIT4_DISP(0x43502000, pkt_type_offset);
770 EMIT4_DISP(0x88500000, 5);
772 case BPF_S_ANC_CPU: /* A = smp_processor_id() */
774 /* l %r5,<d(cpu_nr)> */
775 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
781 default: /* too complex, give up */
784 addrs[i] = jit->prg - jit->start;
791 * Note: for security reasons, bpf code will follow a randomly
792 * sized amount of illegal instructions.
794 struct bpf_binary_header {
799 static struct bpf_binary_header *bpf_alloc_binary(unsigned int bpfsize,
802 struct bpf_binary_header *header;
803 unsigned int sz, hole;
805 /* Most BPF filters are really small, but if some of them fill a page,
806 * allow at least 128 extra bytes for illegal instructions.
808 sz = round_up(bpfsize + sizeof(*header) + 128, PAGE_SIZE);
809 header = module_alloc(sz);
812 memset(header, 0, sz);
813 header->pages = sz / PAGE_SIZE;
814 hole = sz - (bpfsize + sizeof(*header));
815 /* Insert random number of illegal instructions before BPF code
816 * and make sure the first instruction starts at an even address.
818 *image_ptr = &header->image[(prandom_u32() % hole) & -2];
822 void bpf_jit_compile(struct sk_filter *fp)
824 struct bpf_binary_header *header = NULL;
825 unsigned long size, prg_len, lit_len;
826 struct bpf_jit jit, cjit;
832 addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
835 memset(&jit, 0, sizeof(cjit));
836 memset(&cjit, 0, sizeof(cjit));
838 for (pass = 0; pass < 10; pass++) {
842 bpf_jit_prologue(&jit);
843 bpf_jit_noleaks(&jit, fp->insns);
844 for (i = 0; i < fp->len; i++) {
845 if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
849 bpf_jit_epilogue(&jit);
851 WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
852 if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
854 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
855 prg_len = jit.prg - jit.start;
856 lit_len = jit.lit - jit.mid;
857 size = prg_len + lit_len;
858 if (size >= BPF_SIZE_MAX)
860 header = bpf_alloc_binary(size, &jit.start);
863 jit.prg = jit.mid = jit.start + prg_len;
864 jit.lit = jit.end = jit.start + prg_len + lit_len;
865 jit.base_ip += (unsigned long) jit.start;
866 jit.exit_ip += (unsigned long) jit.start;
867 jit.ret0_ip += (unsigned long) jit.start;
871 if (bpf_jit_enable > 1) {
872 bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
874 print_fn_code(jit.start, jit.mid - jit.start);
877 set_memory_ro((unsigned long)header, header->pages);
878 fp->bpf_func = (void *) jit.start;
885 void bpf_jit_free(struct sk_filter *fp)
887 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
888 struct bpf_binary_header *header = (void *)addr;
893 set_memory_rw(addr, header->pages);
894 module_free(NULL, header);