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) {
279 case BPF_S_LDX_B_MSH:
283 case BPF_S_ANC_PROTOCOL:
284 case BPF_S_ANC_PKTTYPE:
285 case BPF_S_ANC_IFINDEX:
287 case BPF_S_ANC_QUEUE:
288 case BPF_S_ANC_HATYPE:
289 case BPF_S_ANC_RXHASH:
291 case BPF_S_ANC_VLAN_TAG:
292 case BPF_S_ANC_VLAN_TAG_PRESENT:
294 /* first instruction sets A register */
302 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
303 unsigned int *addrs, int i, int last)
310 switch (filter->code) {
311 case BPF_S_ALU_ADD_X: /* A += X */
312 jit->seen |= SEEN_XREG;
316 case BPF_S_ALU_ADD_K: /* A += K */
321 EMIT4_IMM(0xa75a0000, K);
322 else if (test_facility(21))
324 EMIT6_IMM(0xc25b0000, K);
326 /* a %r5,<d(K)>(%r13) */
327 EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
329 case BPF_S_ALU_SUB_X: /* A -= X */
330 jit->seen |= SEEN_XREG;
334 case BPF_S_ALU_SUB_K: /* A -= K */
339 EMIT4_IMM(0xa75a0000, -K);
340 else if (test_facility(21))
342 EMIT6_IMM(0xc25b0000, -K);
344 /* s %r5,<d(K)>(%r13) */
345 EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
347 case BPF_S_ALU_MUL_X: /* A *= X */
348 jit->seen |= SEEN_XREG;
352 case BPF_S_ALU_MUL_K: /* A *= K */
355 EMIT4_IMM(0xa75c0000, K);
356 else if (test_facility(34))
358 EMIT6_IMM(0xc2510000, K);
360 /* ms %r5,<d(K)>(%r13) */
361 EMIT4_DISP(0x7150d000, EMIT_CONST(K));
363 case BPF_S_ALU_DIV_X: /* A /= X */
364 jit->seen |= SEEN_XREG | SEEN_RET0;
368 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
374 case BPF_S_ALU_DIV_K: /* A /= K */
379 /* dl %r4,<d(K)>(%r13) */
380 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
382 case BPF_S_ALU_MOD_X: /* A %= X */
383 jit->seen |= SEEN_XREG | SEEN_RET0;
387 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
395 case BPF_S_ALU_MOD_K: /* A %= K */
403 /* dl %r4,<d(K)>(%r13) */
404 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
408 case BPF_S_ALU_AND_X: /* A &= X */
409 jit->seen |= SEEN_XREG;
413 case BPF_S_ALU_AND_K: /* A &= K */
414 if (test_facility(21))
416 EMIT6_IMM(0xc05b0000, K);
418 /* n %r5,<d(K)>(%r13) */
419 EMIT4_DISP(0x5450d000, EMIT_CONST(K));
421 case BPF_S_ALU_OR_X: /* A |= X */
422 jit->seen |= SEEN_XREG;
426 case BPF_S_ALU_OR_K: /* A |= K */
427 if (test_facility(21))
429 EMIT6_IMM(0xc05d0000, K);
431 /* o %r5,<d(K)>(%r13) */
432 EMIT4_DISP(0x5650d000, EMIT_CONST(K));
434 case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
435 case BPF_S_ALU_XOR_X:
436 jit->seen |= SEEN_XREG;
440 case BPF_S_ALU_XOR_K: /* A ^= K */
443 /* x %r5,<d(K)>(%r13) */
444 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
446 case BPF_S_ALU_LSH_X: /* A <<= X; */
447 jit->seen |= SEEN_XREG;
448 /* sll %r5,0(%r12) */
451 case BPF_S_ALU_LSH_K: /* A <<= K */
455 EMIT4_DISP(0x89500000, K);
457 case BPF_S_ALU_RSH_X: /* A >>= X; */
458 jit->seen |= SEEN_XREG;
459 /* srl %r5,0(%r12) */
462 case BPF_S_ALU_RSH_K: /* A >>= K; */
466 EMIT4_DISP(0x88500000, K);
468 case BPF_S_ALU_NEG: /* A = -A */
472 case BPF_S_JMP_JA: /* ip += K */
473 offset = addrs[i + K] + jit->start - jit->prg;
474 EMIT4_PCREL(0xa7f40000, offset);
476 case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
477 mask = 0x200000; /* jh */
479 case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
480 mask = 0xa00000; /* jhe */
482 case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
483 mask = 0x800000; /* je */
484 kbranch: /* Emit compare if the branch targets are different */
485 if (filter->jt != filter->jf) {
488 EMIT4_IMM(0xa75e0000, K);
489 else if (test_facility(21))
491 EMIT6_IMM(0xc25f0000, K);
493 /* c %r5,<d(K)>(%r13) */
494 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
496 branch: if (filter->jt == filter->jf) {
500 offset = addrs[i + filter->jt] + jit->start - jit->prg;
501 EMIT4_PCREL(0xa7f40000, offset);
504 if (filter->jt != 0) {
505 /* brc <mask>,<jt> */
506 offset = addrs[i + filter->jt] + jit->start - jit->prg;
507 EMIT4_PCREL(0xa7040000 | mask, offset);
509 if (filter->jf != 0) {
510 /* brc <mask^15>,<jf> */
511 offset = addrs[i + filter->jf] + jit->start - jit->prg;
512 EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
515 case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
516 mask = 0x700000; /* jnz */
517 /* Emit test if the branch targets are different */
518 if (filter->jt != filter->jf) {
522 /* n %r4,<d(K)>(%r13) */
523 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
526 EMIT4_IMM(0xa7510000, K);
529 case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
530 mask = 0x200000; /* jh */
532 case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
533 mask = 0xa00000; /* jhe */
535 case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
536 mask = 0x800000; /* je */
537 xbranch: /* Emit compare if the branch targets are different */
538 if (filter->jt != filter->jf) {
539 jit->seen |= SEEN_XREG;
544 case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
545 mask = 0x700000; /* jnz */
546 /* Emit test if the branch targets are different */
547 if (filter->jt != filter->jf) {
548 jit->seen |= SEEN_XREG;
555 case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
556 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
557 offset = jit->off_load_word;
559 case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
560 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
561 offset = jit->off_load_half;
563 case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
564 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
565 offset = jit->off_load_byte;
566 load_abs: if ((int) K < 0)
568 call_fn: /* lg %r1,<d(function)>(%r13) */
569 EMIT6_DISP(0xe310d000, 0x0004, offset);
570 /* l %r3,<d(K)>(%r13) */
571 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
575 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
577 case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
578 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
579 offset = jit->off_load_iword;
581 case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
582 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
583 offset = jit->off_load_ihalf;
585 case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
586 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
587 offset = jit->off_load_ibyte;
589 case BPF_S_LDX_B_MSH:
590 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
591 jit->seen |= SEEN_RET0;
594 EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
597 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
598 offset = jit->off_load_bmsh;
600 case BPF_S_LD_W_LEN: /* A = skb->len; */
601 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
602 /* l %r5,<d(len)>(%r2) */
603 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
605 case BPF_S_LDX_W_LEN: /* X = skb->len; */
606 jit->seen |= SEEN_XREG;
607 /* l %r12,<d(len)>(%r2) */
608 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
610 case BPF_S_LD_IMM: /* A = K */
613 EMIT4_IMM(0xa7580000, K);
614 else if (test_facility(21))
616 EMIT6_IMM(0xc05f0000, K);
618 /* l %r5,<d(K)>(%r13) */
619 EMIT4_DISP(0x5850d000, EMIT_CONST(K));
621 case BPF_S_LDX_IMM: /* X = K */
622 jit->seen |= SEEN_XREG;
625 EMIT4_IMM(0xa7c80000, K);
626 else if (test_facility(21))
628 EMIT6_IMM(0xc0cf0000, K);
630 /* l %r12,<d(K)>(%r13) */
631 EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
633 case BPF_S_LD_MEM: /* A = mem[K] */
634 jit->seen |= SEEN_MEM;
635 /* l %r5,<K>(%r15) */
636 EMIT4_DISP(0x5850f000,
637 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
639 case BPF_S_LDX_MEM: /* X = mem[K] */
640 jit->seen |= SEEN_XREG | SEEN_MEM;
641 /* l %r12,<K>(%r15) */
642 EMIT4_DISP(0x58c0f000,
643 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
645 case BPF_S_MISC_TAX: /* X = A */
646 jit->seen |= SEEN_XREG;
650 case BPF_S_MISC_TXA: /* A = X */
651 jit->seen |= SEEN_XREG;
657 jit->seen |= SEEN_RET0;
661 EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
665 EMIT4_IMM(0xa7290000, K);
667 /* llgf %r2,<K>(%r13) */
668 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
670 if (last && !(jit->seen & SEEN_RET0))
672 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
679 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
681 case BPF_S_ST: /* mem[K] = A */
682 jit->seen |= SEEN_MEM;
683 /* st %r5,<K>(%r15) */
684 EMIT4_DISP(0x5050f000,
685 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
687 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
688 jit->seen |= SEEN_XREG | SEEN_MEM;
689 /* st %r12,<K>(%r15) */
690 EMIT4_DISP(0x50c0f000,
691 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
693 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
694 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
697 /* icm %r5,3,<d(protocol)>(%r2) */
698 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
700 case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
701 * A = skb->dev->ifindex */
702 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
703 jit->seen |= SEEN_RET0;
704 /* lg %r1,<d(dev)>(%r2) */
705 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
709 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
710 /* l %r5,<d(ifindex)>(%r1) */
711 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
713 case BPF_S_ANC_MARK: /* A = skb->mark */
714 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
715 /* l %r5,<d(mark)>(%r2) */
716 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
718 case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
719 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
722 /* icm %r5,3,<d(queue_mapping)>(%r2) */
723 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
725 case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0;
726 * A = skb->dev->type */
727 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
728 jit->seen |= SEEN_RET0;
729 /* lg %r1,<d(dev)>(%r2) */
730 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
734 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
737 /* icm %r5,3,<d(type)>(%r1) */
738 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
740 case BPF_S_ANC_RXHASH: /* A = skb->hash */
741 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
742 /* l %r5,<d(hash)>(%r2) */
743 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, hash));
745 case BPF_S_ANC_VLAN_TAG:
746 case BPF_S_ANC_VLAN_TAG_PRESENT:
747 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
748 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
751 /* icm %r5,3,<d(vlan_tci)>(%r2) */
752 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
753 if (filter->code == BPF_S_ANC_VLAN_TAG) {
754 /* nill %r5,0xefff */
755 EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
757 /* nill %r5,0x1000 */
758 EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
760 EMIT4_DISP(0x88500000, 12);
763 case BPF_S_ANC_PKTTYPE:
764 if (pkt_type_offset < 0)
768 /* ic %r5,<d(pkt_type_offset)>(%r2) */
769 EMIT4_DISP(0x43502000, pkt_type_offset);
771 EMIT4_DISP(0x88500000, 5);
773 case BPF_S_ANC_CPU: /* A = smp_processor_id() */
775 /* l %r5,<d(cpu_nr)> */
776 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
782 default: /* too complex, give up */
785 addrs[i] = jit->prg - jit->start;
792 * Note: for security reasons, bpf code will follow a randomly
793 * sized amount of illegal instructions.
795 struct bpf_binary_header {
800 static struct bpf_binary_header *bpf_alloc_binary(unsigned int bpfsize,
803 struct bpf_binary_header *header;
804 unsigned int sz, hole;
806 /* Most BPF filters are really small, but if some of them fill a page,
807 * allow at least 128 extra bytes for illegal instructions.
809 sz = round_up(bpfsize + sizeof(*header) + 128, PAGE_SIZE);
810 header = module_alloc(sz);
813 memset(header, 0, sz);
814 header->pages = sz / PAGE_SIZE;
815 hole = sz - (bpfsize + sizeof(*header));
816 /* Insert random number of illegal instructions before BPF code
817 * and make sure the first instruction starts at an even address.
819 *image_ptr = &header->image[(prandom_u32() % hole) & -2];
823 void bpf_jit_compile(struct sk_filter *fp)
825 struct bpf_binary_header *header = NULL;
826 unsigned long size, prg_len, lit_len;
827 struct bpf_jit jit, cjit;
833 addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
836 memset(&jit, 0, sizeof(cjit));
837 memset(&cjit, 0, sizeof(cjit));
839 for (pass = 0; pass < 10; pass++) {
843 bpf_jit_prologue(&jit);
844 bpf_jit_noleaks(&jit, fp->insns);
845 for (i = 0; i < fp->len; i++) {
846 if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
850 bpf_jit_epilogue(&jit);
852 WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
853 if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
855 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
856 prg_len = jit.prg - jit.start;
857 lit_len = jit.lit - jit.mid;
858 size = prg_len + lit_len;
859 if (size >= BPF_SIZE_MAX)
861 header = bpf_alloc_binary(size, &jit.start);
864 jit.prg = jit.mid = jit.start + prg_len;
865 jit.lit = jit.end = jit.start + prg_len + lit_len;
866 jit.base_ip += (unsigned long) jit.start;
867 jit.exit_ip += (unsigned long) jit.start;
868 jit.ret0_ip += (unsigned long) jit.start;
872 if (bpf_jit_enable > 1) {
873 bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
875 print_fn_code(jit.start, jit.mid - jit.start);
878 set_memory_ro((unsigned long)header, header->pages);
879 fp->bpf_func = (void *) jit.start;
886 void bpf_jit_free(struct sk_filter *fp)
888 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
889 struct bpf_binary_header *header = (void *)addr;
894 set_memory_rw(addr, header->pages);
895 module_free(NULL, header);