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/filter.h>
11 #include <asm/cacheflush.h>
12 #include <asm/processor.h>
13 #include <asm/facility.h>
18 * %r3 = offset parameter
19 * %r4 = scratch register / length parameter
20 * %r5 = BPF A accumulator
21 * %r8 = return address
22 * %r9 = save register for skb pointer
24 * %r11 = skb->len - skb->data_len (headlen)
25 * %r12 = BPF X accumulator
26 * %r13 = literal pool pointer
27 * 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
29 int bpf_jit_enable __read_mostly
;
32 * assembly code in arch/x86/net/bpf_jit.S
34 extern u8 sk_load_word
[], sk_load_half
[], sk_load_byte
[], sk_load_byte_msh
[];
35 extern u8 sk_load_word_ind
[], sk_load_half_ind
[], sk_load_byte_ind
[];
47 unsigned int off_load_word
;
48 unsigned int off_load_half
;
49 unsigned int off_load_byte
;
50 unsigned int off_load_bmsh
;
51 unsigned int off_load_iword
;
52 unsigned int off_load_ihalf
;
53 unsigned int off_load_ibyte
;
56 #define BPF_SIZE_MAX 4096 /* Max size for program */
58 #define SEEN_DATAREF 1 /* might call external helpers */
59 #define SEEN_XREG 2 /* ebx is used */
60 #define SEEN_MEM 4 /* use mem[] for temporary storage */
61 #define SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */
62 #define SEEN_LITERAL 16 /* code uses literals */
63 #define SEEN_LOAD_WORD 32 /* code uses sk_load_word */
64 #define SEEN_LOAD_HALF 64 /* code uses sk_load_half */
65 #define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */
66 #define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */
67 #define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */
68 #define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */
69 #define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */
73 if (jit->prg + 2 <= jit->mid) \
74 *(u16 *) jit->prg = op; \
80 if (jit->prg + 4 <= jit->mid) \
81 *(u32 *) jit->prg = op; \
85 #define EMIT4_DISP(op, disp) \
87 unsigned int __disp = (disp) & 0xfff; \
91 #define EMIT4_IMM(op, imm) \
93 unsigned int __imm = (imm) & 0xffff; \
97 #define EMIT4_PCREL(op, pcrel) \
99 long __pcrel = ((pcrel) >> 1) & 0xffff; \
100 EMIT4(op | __pcrel); \
103 #define EMIT6(op1, op2) \
105 if (jit->prg + 6 <= jit->mid) { \
106 *(u32 *) jit->prg = op1; \
107 *(u16 *) (jit->prg + 4) = op2; \
112 #define EMIT6_DISP(op1, op2, disp) \
114 unsigned int __disp = (disp) & 0xfff; \
115 EMIT6(op1 | __disp, op2); \
118 #define EMIT6_IMM(op, imm) \
120 unsigned int __imm = (imm); \
121 EMIT6(op | (__imm >> 16), __imm & 0xffff); \
124 #define EMIT_CONST(val) \
127 ret = (unsigned int) (jit->lit - jit->base_ip); \
128 jit->seen |= SEEN_LITERAL; \
129 if (jit->lit + 4 <= jit->end) \
130 *(u32 *) jit->lit = val; \
135 #define EMIT_FN_CONST(bit, fn) \
138 ret = (unsigned int) (jit->lit - jit->base_ip); \
139 if (jit->seen & bit) { \
140 jit->seen |= SEEN_LITERAL; \
141 if (jit->lit + 8 <= jit->end) \
142 *(void **) jit->lit = fn; \
148 static void bpf_jit_prologue(struct bpf_jit
*jit
)
150 /* Save registers and create stack frame if necessary */
151 if (jit
->seen
& SEEN_DATAREF
) {
152 /* stmg %r8,%r15,88(%r15) */
153 EMIT6(0xeb8ff058, 0x0024);
156 /* ahi %r15,<offset> */
157 EMIT4_IMM(0xa7fa0000, (jit
->seen
& SEEN_MEM
) ? -112 : -80);
158 /* stg %r14,152(%r15) */
159 EMIT6(0xe3e0f098, 0x0024);
160 } else if ((jit
->seen
& SEEN_XREG
) && (jit
->seen
& SEEN_LITERAL
))
161 /* stmg %r12,%r13,120(%r15) */
162 EMIT6(0xebcdf078, 0x0024);
163 else if (jit
->seen
& SEEN_XREG
)
164 /* stg %r12,120(%r15) */
165 EMIT6(0xe3c0f078, 0x0024);
166 else if (jit
->seen
& SEEN_LITERAL
)
167 /* stg %r13,128(%r15) */
168 EMIT6(0xe3d0f080, 0x0024);
170 /* Setup literal pool */
171 if (jit
->seen
& SEEN_LITERAL
) {
174 jit
->base_ip
= jit
->prg
;
176 jit
->off_load_word
= EMIT_FN_CONST(SEEN_LOAD_WORD
, sk_load_word
);
177 jit
->off_load_half
= EMIT_FN_CONST(SEEN_LOAD_HALF
, sk_load_half
);
178 jit
->off_load_byte
= EMIT_FN_CONST(SEEN_LOAD_BYTE
, sk_load_byte
);
179 jit
->off_load_bmsh
= EMIT_FN_CONST(SEEN_LOAD_BMSH
, sk_load_byte_msh
);
180 jit
->off_load_iword
= EMIT_FN_CONST(SEEN_LOAD_IWORD
, sk_load_word_ind
);
181 jit
->off_load_ihalf
= EMIT_FN_CONST(SEEN_LOAD_IHALF
, sk_load_half_ind
);
182 jit
->off_load_ibyte
= EMIT_FN_CONST(SEEN_LOAD_IBYTE
, sk_load_byte_ind
);
184 /* Filter needs to access skb data */
185 if (jit
->seen
& SEEN_DATAREF
) {
186 /* l %r11,<len>(%r2) */
187 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff
, len
));
188 /* s %r11,<data_len>(%r2) */
189 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff
, data_len
));
190 /* lg %r10,<data>(%r2) */
191 EMIT6_DISP(0xe3a02000, 0x0004,
192 offsetof(struct sk_buff
, data
));
196 static void bpf_jit_epilogue(struct bpf_jit
*jit
)
199 if (jit
->seen
& SEEN_RET0
) {
200 jit
->ret0_ip
= jit
->prg
;
204 jit
->exit_ip
= jit
->prg
;
205 /* Restore registers */
206 if (jit
->seen
& SEEN_DATAREF
)
207 /* lmg %r8,%r15,<offset>(%r15) */
208 EMIT6_DISP(0xeb8ff000, 0x0004,
209 (jit
->seen
& SEEN_MEM
) ? 200 : 168);
210 else if ((jit
->seen
& SEEN_XREG
) && (jit
->seen
& SEEN_LITERAL
))
211 /* lmg %r12,%r13,120(%r15) */
212 EMIT6(0xebcdf078, 0x0004);
213 else if (jit
->seen
& SEEN_XREG
)
214 /* lg %r12,120(%r15) */
215 EMIT6(0xe3c0f078, 0x0004);
216 else if (jit
->seen
& SEEN_LITERAL
)
217 /* lg %r13,128(%r15) */
218 EMIT6(0xe3d0f080, 0x0004);
224 * make sure we dont leak kernel information to user
226 static void bpf_jit_noleaks(struct bpf_jit
*jit
, struct sock_filter
*filter
)
228 /* Clear temporary memory if (seen & SEEN_MEM) */
229 if (jit
->seen
& SEEN_MEM
)
230 /* xc 0(64,%r15),0(%r15) */
231 EMIT6(0xd73ff000, 0xf000);
232 /* Clear X if (seen & SEEN_XREG) */
233 if (jit
->seen
& SEEN_XREG
)
236 /* Clear A if the first register does not set it. */
237 switch (filter
[0].code
) {
245 case BPF_S_LDX_B_MSH
:
249 case BPF_S_ANC_PROTOCOL
:
250 case BPF_S_ANC_PKTTYPE
:
251 case BPF_S_ANC_IFINDEX
:
253 case BPF_S_ANC_QUEUE
:
254 case BPF_S_ANC_HATYPE
:
255 case BPF_S_ANC_RXHASH
:
258 /* first instruction sets A register */
266 static int bpf_jit_insn(struct bpf_jit
*jit
, struct sock_filter
*filter
,
267 unsigned int *addrs
, int i
, int last
)
274 switch (filter
->code
) {
275 case BPF_S_ALU_ADD_X
: /* A += X */
276 jit
->seen
|= SEEN_XREG
;
280 case BPF_S_ALU_ADD_K
: /* A += K */
285 EMIT4_IMM(0xa75a0000, K
);
286 else if (test_facility(21))
288 EMIT6_IMM(0xc25b0000, K
);
290 /* a %r5,<d(K)>(%r13) */
291 EMIT4_DISP(0x5a50d000, EMIT_CONST(K
));
293 case BPF_S_ALU_SUB_X
: /* A -= X */
294 jit
->seen
|= SEEN_XREG
;
298 case BPF_S_ALU_SUB_K
: /* A -= K */
303 EMIT4_IMM(0xa75a0000, -K
);
304 else if (test_facility(21))
306 EMIT6_IMM(0xc25b0000, -K
);
308 /* s %r5,<d(K)>(%r13) */
309 EMIT4_DISP(0x5b50d000, EMIT_CONST(K
));
311 case BPF_S_ALU_MUL_X
: /* A *= X */
312 jit
->seen
|= SEEN_XREG
;
316 case BPF_S_ALU_MUL_K
: /* A *= K */
319 EMIT4_IMM(0xa75c0000, K
);
320 else if (test_facility(34))
322 EMIT6_IMM(0xc2510000, K
);
324 /* ms %r5,<d(K)>(%r13) */
325 EMIT4_DISP(0x7150d000, EMIT_CONST(K
));
327 case BPF_S_ALU_DIV_X
: /* A /= X */
328 jit
->seen
|= SEEN_XREG
| SEEN_RET0
;
332 EMIT4_PCREL(0xa7840000, (jit
->ret0_ip
- jit
->prg
));
338 case BPF_S_ALU_DIV_K
: /* A = reciprocal_divide(A, K) */
339 /* m %r4,<d(K)>(%r13) */
340 EMIT4_DISP(0x5c40d000, EMIT_CONST(K
));
344 case BPF_S_ALU_AND_X
: /* A &= X */
345 jit
->seen
|= SEEN_XREG
;
349 case BPF_S_ALU_AND_K
: /* A &= K */
350 if (test_facility(21))
352 EMIT6_IMM(0xc05b0000, K
);
354 /* n %r5,<d(K)>(%r13) */
355 EMIT4_DISP(0x5450d000, EMIT_CONST(K
));
357 case BPF_S_ALU_OR_X
: /* A |= X */
358 jit
->seen
|= SEEN_XREG
;
362 case BPF_S_ALU_OR_K
: /* A |= K */
363 if (test_facility(21))
365 EMIT6_IMM(0xc05d0000, K
);
367 /* o %r5,<d(K)>(%r13) */
368 EMIT4_DISP(0x5650d000, EMIT_CONST(K
));
370 case BPF_S_ANC_ALU_XOR_X
: /* A ^= X; */
371 jit
->seen
|= SEEN_XREG
;
375 case BPF_S_ALU_LSH_X
: /* A <<= X; */
376 jit
->seen
|= SEEN_XREG
;
377 /* sll %r5,0(%r12) */
380 case BPF_S_ALU_LSH_K
: /* A <<= K */
384 EMIT4_DISP(0x89500000, K
);
386 case BPF_S_ALU_RSH_X
: /* A >>= X; */
387 jit
->seen
|= SEEN_XREG
;
388 /* srl %r5,0(%r12) */
391 case BPF_S_ALU_RSH_K
: /* A >>= K; */
395 EMIT4_DISP(0x88500000, K
);
397 case BPF_S_ALU_NEG
: /* A = -A */
401 case BPF_S_JMP_JA
: /* ip += K */
402 offset
= addrs
[i
+ K
] + jit
->start
- jit
->prg
;
403 EMIT4_PCREL(0xa7f40000, offset
);
405 case BPF_S_JMP_JGT_K
: /* ip += (A > K) ? jt : jf */
406 mask
= 0x200000; /* jh */
408 case BPF_S_JMP_JGE_K
: /* ip += (A >= K) ? jt : jf */
409 mask
= 0xa00000; /* jhe */
411 case BPF_S_JMP_JEQ_K
: /* ip += (A == K) ? jt : jf */
412 mask
= 0x800000; /* je */
413 kbranch
: /* Emit compare if the branch targets are different */
414 if (filter
->jt
!= filter
->jf
) {
417 EMIT4_IMM(0xa75e0000, K
);
418 else if (test_facility(21))
420 EMIT6_IMM(0xc25f0000, K
);
422 /* c %r5,<d(K)>(%r13) */
423 EMIT4_DISP(0x5950d000, EMIT_CONST(K
));
425 branch
: if (filter
->jt
== filter
->jf
) {
429 offset
= addrs
[i
+ filter
->jt
] + jit
->start
- jit
->prg
;
430 EMIT4_PCREL(0xa7f40000, offset
);
433 if (filter
->jt
!= 0) {
434 /* brc <mask>,<jt> */
435 offset
= addrs
[i
+ filter
->jt
] + jit
->start
- jit
->prg
;
436 EMIT4_PCREL(0xa7040000 | mask
, offset
);
438 if (filter
->jf
!= 0) {
439 /* brc <mask^15>,<jf> */
440 offset
= addrs
[i
+ filter
->jf
] + jit
->start
- jit
->prg
;
441 EMIT4_PCREL(0xa7040000 | (mask
^ 0xf00000), offset
);
444 case BPF_S_JMP_JSET_K
: /* ip += (A & K) ? jt : jf */
445 mask
= 0x700000; /* jnz */
446 /* Emit test if the branch targets are different */
447 if (filter
->jt
!= filter
->jf
) {
451 /* n %r4,<d(K)>(%r13) */
452 EMIT4_DISP(0x5440d000, EMIT_CONST(K
));
455 EMIT4_IMM(0xa7510000, K
);
458 case BPF_S_JMP_JGT_X
: /* ip += (A > X) ? jt : jf */
459 mask
= 0x200000; /* jh */
461 case BPF_S_JMP_JGE_X
: /* ip += (A >= X) ? jt : jf */
462 mask
= 0xa00000; /* jhe */
464 case BPF_S_JMP_JEQ_X
: /* ip += (A == X) ? jt : jf */
465 mask
= 0x800000; /* je */
466 xbranch
: /* Emit compare if the branch targets are different */
467 if (filter
->jt
!= filter
->jf
) {
468 jit
->seen
|= SEEN_XREG
;
473 case BPF_S_JMP_JSET_X
: /* ip += (A & X) ? jt : jf */
474 mask
= 0x700000; /* jnz */
475 /* Emit test if the branch targets are different */
476 if (filter
->jt
!= filter
->jf
) {
477 jit
->seen
|= SEEN_XREG
;
484 case BPF_S_LD_W_ABS
: /* A = *(u32 *) (skb->data+K) */
485 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_WORD
;
486 offset
= jit
->off_load_word
;
488 case BPF_S_LD_H_ABS
: /* A = *(u16 *) (skb->data+K) */
489 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_HALF
;
490 offset
= jit
->off_load_half
;
492 case BPF_S_LD_B_ABS
: /* A = *(u8 *) (skb->data+K) */
493 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_BYTE
;
494 offset
= jit
->off_load_byte
;
495 load_abs
: if ((int) K
< 0)
497 call_fn
: /* lg %r1,<d(function)>(%r13) */
498 EMIT6_DISP(0xe310d000, 0x0004, offset
);
499 /* l %r3,<d(K)>(%r13) */
500 EMIT4_DISP(0x5830d000, EMIT_CONST(K
));
504 EMIT4_PCREL(0xa7740000, (jit
->ret0_ip
- jit
->prg
));
506 case BPF_S_LD_W_IND
: /* A = *(u32 *) (skb->data+K+X) */
507 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_IWORD
;
508 offset
= jit
->off_load_iword
;
510 case BPF_S_LD_H_IND
: /* A = *(u16 *) (skb->data+K+X) */
511 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_IHALF
;
512 offset
= jit
->off_load_ihalf
;
514 case BPF_S_LD_B_IND
: /* A = *(u8 *) (skb->data+K+X) */
515 jit
->seen
|= SEEN_DATAREF
| SEEN_RET0
| SEEN_LOAD_IBYTE
;
516 offset
= jit
->off_load_ibyte
;
518 case BPF_S_LDX_B_MSH
:
519 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
520 jit
->seen
|= SEEN_RET0
;
523 EMIT4_PCREL(0xa7f40000, (jit
->ret0_ip
- jit
->prg
));
526 jit
->seen
|= SEEN_DATAREF
| SEEN_LOAD_BMSH
;
527 offset
= jit
->off_load_bmsh
;
529 case BPF_S_LD_W_LEN
: /* A = skb->len; */
530 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, len
) != 4);
531 /* l %r5,<d(len)>(%r2) */
532 EMIT4_DISP(0x58502000, offsetof(struct sk_buff
, len
));
534 case BPF_S_LDX_W_LEN
: /* X = skb->len; */
535 jit
->seen
|= SEEN_XREG
;
536 /* l %r12,<d(len)>(%r2) */
537 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff
, len
));
539 case BPF_S_LD_IMM
: /* A = K */
542 EMIT4_IMM(0xa7580000, K
);
543 else if (test_facility(21))
545 EMIT6_IMM(0xc05f0000, K
);
547 /* l %r5,<d(K)>(%r13) */
548 EMIT4_DISP(0x5850d000, EMIT_CONST(K
));
550 case BPF_S_LDX_IMM
: /* X = K */
551 jit
->seen
|= SEEN_XREG
;
554 EMIT4_IMM(0xa7c80000, K
);
555 else if (test_facility(21))
557 EMIT6_IMM(0xc0cf0000, K
);
559 /* l %r12,<d(K)>(%r13) */
560 EMIT4_DISP(0x58c0d000, EMIT_CONST(K
));
562 case BPF_S_LD_MEM
: /* A = mem[K] */
563 jit
->seen
|= SEEN_MEM
;
564 /* l %r5,<K>(%r15) */
565 EMIT4_DISP(0x5850f000,
566 (jit
->seen
& SEEN_DATAREF
) ? 160 + K
*4 : K
*4);
568 case BPF_S_LDX_MEM
: /* X = mem[K] */
569 jit
->seen
|= SEEN_XREG
| SEEN_MEM
;
570 /* l %r12,<K>(%r15) */
571 EMIT4_DISP(0x58c0f000,
572 (jit
->seen
& SEEN_DATAREF
) ? 160 + K
*4 : K
*4);
574 case BPF_S_MISC_TAX
: /* X = A */
575 jit
->seen
|= SEEN_XREG
;
579 case BPF_S_MISC_TXA
: /* A = X */
580 jit
->seen
|= SEEN_XREG
;
586 jit
->seen
|= SEEN_RET0
;
590 EMIT4_PCREL(0xa7f40000, jit
->ret0_ip
- jit
->prg
);
594 EMIT4_IMM(0xa7290000, K
);
596 /* llgf %r2,<K>(%r13) */
597 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K
));
599 if (last
&& !(jit
->seen
& SEEN_RET0
))
601 EMIT4_PCREL(0xa7f40000, jit
->exit_ip
- jit
->prg
);
608 EMIT4_PCREL(0xa7f40000, jit
->exit_ip
- jit
->prg
);
610 case BPF_S_ST
: /* mem[K] = A */
611 jit
->seen
|= SEEN_MEM
;
612 /* st %r5,<K>(%r15) */
613 EMIT4_DISP(0x5050f000,
614 (jit
->seen
& SEEN_DATAREF
) ? 160 + K
*4 : K
*4);
616 case BPF_S_STX
: /* mem[K] = X : mov %ebx,off8(%rbp) */
617 jit
->seen
|= SEEN_XREG
| SEEN_MEM
;
618 /* st %r12,<K>(%r15) */
619 EMIT4_DISP(0x50c0f000,
620 (jit
->seen
& SEEN_DATAREF
) ? 160 + K
*4 : K
*4);
622 case BPF_S_ANC_PROTOCOL
: /* A = ntohs(skb->protocol); */
623 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, protocol
) != 2);
626 /* icm %r5,3,<d(protocol)>(%r2) */
627 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff
, protocol
));
629 case BPF_S_ANC_IFINDEX
: /* if (!skb->dev) return 0;
630 * A = skb->dev->ifindex */
631 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device
, ifindex
) != 4);
632 jit
->seen
|= SEEN_RET0
;
633 /* lg %r1,<d(dev)>(%r2) */
634 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff
, dev
));
638 EMIT4_PCREL(0xa7840000, jit
->ret0_ip
- jit
->prg
);
639 /* l %r5,<d(ifindex)>(%r1) */
640 EMIT4_DISP(0x58501000, offsetof(struct net_device
, ifindex
));
642 case BPF_S_ANC_MARK
: /* A = skb->mark */
643 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, mark
) != 4);
644 /* l %r5,<d(mark)>(%r2) */
645 EMIT4_DISP(0x58502000, offsetof(struct sk_buff
, mark
));
647 case BPF_S_ANC_QUEUE
: /* A = skb->queue_mapping */
648 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, queue_mapping
) != 2);
651 /* icm %r5,3,<d(queue_mapping)>(%r2) */
652 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff
, queue_mapping
));
654 case BPF_S_ANC_HATYPE
: /* if (!skb->dev) return 0;
655 * A = skb->dev->type */
656 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device
, type
) != 2);
657 jit
->seen
|= SEEN_RET0
;
658 /* lg %r1,<d(dev)>(%r2) */
659 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff
, dev
));
663 EMIT4_PCREL(0xa7840000, jit
->ret0_ip
- jit
->prg
);
666 /* icm %r5,3,<d(type)>(%r1) */
667 EMIT4_DISP(0xbf531000, offsetof(struct net_device
, type
));
669 case BPF_S_ANC_RXHASH
: /* A = skb->rxhash */
670 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, rxhash
) != 4);
671 /* l %r5,<d(rxhash)>(%r2) */
672 EMIT4_DISP(0x58502000, offsetof(struct sk_buff
, rxhash
));
674 case BPF_S_ANC_CPU
: /* A = smp_processor_id() */
676 /* l %r5,<d(cpu_nr)> */
677 EMIT4_DISP(0x58500000, offsetof(struct _lowcore
, cpu_nr
));
683 default: /* too complex, give up */
686 addrs
[i
] = jit
->prg
- jit
->start
;
692 void bpf_jit_compile(struct sk_filter
*fp
)
694 unsigned long size
, prg_len
, lit_len
;
695 struct bpf_jit jit
, cjit
;
701 addrs
= kmalloc(fp
->len
* sizeof(*addrs
), GFP_KERNEL
);
704 memset(addrs
, 0, fp
->len
* sizeof(*addrs
));
705 memset(&jit
, 0, sizeof(cjit
));
706 memset(&cjit
, 0, sizeof(cjit
));
708 for (pass
= 0; pass
< 10; pass
++) {
712 bpf_jit_prologue(&jit
);
713 bpf_jit_noleaks(&jit
, fp
->insns
);
714 for (i
= 0; i
< fp
->len
; i
++) {
715 if (bpf_jit_insn(&jit
, fp
->insns
+ i
, addrs
, i
,
719 bpf_jit_epilogue(&jit
);
721 WARN_ON(jit
.prg
> cjit
.prg
|| jit
.lit
> cjit
.lit
);
722 if (memcmp(&jit
, &cjit
, sizeof(jit
)) == 0)
724 } else if (jit
.prg
== cjit
.prg
&& jit
.lit
== cjit
.lit
) {
725 prg_len
= jit
.prg
- jit
.start
;
726 lit_len
= jit
.lit
- jit
.mid
;
727 size
= max_t(unsigned long, prg_len
+ lit_len
,
728 sizeof(struct work_struct
));
729 if (size
>= BPF_SIZE_MAX
)
731 jit
.start
= module_alloc(size
);
734 jit
.prg
= jit
.mid
= jit
.start
+ prg_len
;
735 jit
.lit
= jit
.end
= jit
.start
+ prg_len
+ lit_len
;
736 jit
.base_ip
+= (unsigned long) jit
.start
;
737 jit
.exit_ip
+= (unsigned long) jit
.start
;
738 jit
.ret0_ip
+= (unsigned long) jit
.start
;
742 if (bpf_jit_enable
> 1) {
743 pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
744 fp
->len
, jit
.end
- jit
.start
, pass
, jit
.start
);
746 printk(KERN_ERR
"JIT code:\n");
747 print_fn_code(jit
.start
, jit
.mid
- jit
.start
);
748 print_hex_dump(KERN_ERR
, "JIT literals:\n",
749 DUMP_PREFIX_ADDRESS
, 16, 1,
750 jit
.mid
, jit
.end
- jit
.mid
, false);
754 fp
->bpf_func
= (void *) jit
.start
;
759 static void jit_free_defer(struct work_struct
*arg
)
761 module_free(NULL
, arg
);
764 /* run from softirq, we must use a work_struct to call
765 * module_free() from process context
767 void bpf_jit_free(struct sk_filter
*fp
)
769 struct work_struct
*work
;
771 if (fp
->bpf_func
== sk_run_filter
)
773 work
= (struct work_struct
*)fp
->bpf_func
;
774 INIT_WORK(work
, jit_free_defer
);