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spi: Use dev_get_drvdata at appropriate places
[deliverable/linux.git] / arch / s390 / net / bpf_jit_comp.c
1 /*
2 * BPF Jit compiler for s390.
3 *
4 * Copyright IBM Corp. 2012
5 *
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 */
8 #include <linux/moduleloader.h>
9 #include <linux/netdevice.h>
10 #include <linux/if_vlan.h>
11 #include <linux/filter.h>
12 #include <asm/cacheflush.h>
13 #include <asm/processor.h>
14 #include <asm/facility.h>
15
16 /*
17 * Conventions:
18 * %r2 = skb pointer
19 * %r3 = offset parameter
20 * %r4 = scratch register / length parameter
21 * %r5 = BPF A accumulator
22 * %r8 = return address
23 * %r9 = save register for skb pointer
24 * %r10 = skb->data
25 * %r11 = skb->len - skb->data_len (headlen)
26 * %r12 = BPF X accumulator
27 * %r13 = literal pool pointer
28 * 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
29 */
30 int bpf_jit_enable __read_mostly;
31
32 /*
33 * assembly code in arch/x86/net/bpf_jit.S
34 */
35 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
36 extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
37
38 struct bpf_jit {
39 unsigned int seen;
40 u8 *start;
41 u8 *prg;
42 u8 *mid;
43 u8 *lit;
44 u8 *end;
45 u8 *base_ip;
46 u8 *ret0_ip;
47 u8 *exit_ip;
48 unsigned int off_load_word;
49 unsigned int off_load_half;
50 unsigned int off_load_byte;
51 unsigned int off_load_bmsh;
52 unsigned int off_load_iword;
53 unsigned int off_load_ihalf;
54 unsigned int off_load_ibyte;
55 };
56
57 #define BPF_SIZE_MAX 4096 /* Max size for program */
58
59 #define SEEN_DATAREF 1 /* might call external helpers */
60 #define SEEN_XREG 2 /* ebx is used */
61 #define SEEN_MEM 4 /* use mem[] for temporary storage */
62 #define SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */
63 #define SEEN_LITERAL 16 /* code uses literals */
64 #define SEEN_LOAD_WORD 32 /* code uses sk_load_word */
65 #define SEEN_LOAD_HALF 64 /* code uses sk_load_half */
66 #define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */
67 #define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */
68 #define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */
69 #define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */
70 #define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */
71
72 #define EMIT2(op) \
73 ({ \
74 if (jit->prg + 2 <= jit->mid) \
75 *(u16 *) jit->prg = op; \
76 jit->prg += 2; \
77 })
78
79 #define EMIT4(op) \
80 ({ \
81 if (jit->prg + 4 <= jit->mid) \
82 *(u32 *) jit->prg = op; \
83 jit->prg += 4; \
84 })
85
86 #define EMIT4_DISP(op, disp) \
87 ({ \
88 unsigned int __disp = (disp) & 0xfff; \
89 EMIT4(op | __disp); \
90 })
91
92 #define EMIT4_IMM(op, imm) \
93 ({ \
94 unsigned int __imm = (imm) & 0xffff; \
95 EMIT4(op | __imm); \
96 })
97
98 #define EMIT4_PCREL(op, pcrel) \
99 ({ \
100 long __pcrel = ((pcrel) >> 1) & 0xffff; \
101 EMIT4(op | __pcrel); \
102 })
103
104 #define EMIT6(op1, op2) \
105 ({ \
106 if (jit->prg + 6 <= jit->mid) { \
107 *(u32 *) jit->prg = op1; \
108 *(u16 *) (jit->prg + 4) = op2; \
109 } \
110 jit->prg += 6; \
111 })
112
113 #define EMIT6_DISP(op1, op2, disp) \
114 ({ \
115 unsigned int __disp = (disp) & 0xfff; \
116 EMIT6(op1 | __disp, op2); \
117 })
118
119 #define EMIT6_IMM(op, imm) \
120 ({ \
121 unsigned int __imm = (imm); \
122 EMIT6(op | (__imm >> 16), __imm & 0xffff); \
123 })
124
125 #define EMIT_CONST(val) \
126 ({ \
127 unsigned int ret; \
128 ret = (unsigned int) (jit->lit - jit->base_ip); \
129 jit->seen |= SEEN_LITERAL; \
130 if (jit->lit + 4 <= jit->end) \
131 *(u32 *) jit->lit = val; \
132 jit->lit += 4; \
133 ret; \
134 })
135
136 #define EMIT_FN_CONST(bit, fn) \
137 ({ \
138 unsigned int ret; \
139 ret = (unsigned int) (jit->lit - jit->base_ip); \
140 if (jit->seen & bit) { \
141 jit->seen |= SEEN_LITERAL; \
142 if (jit->lit + 8 <= jit->end) \
143 *(void **) jit->lit = fn; \
144 jit->lit += 8; \
145 } \
146 ret; \
147 })
148
149 static void bpf_jit_prologue(struct bpf_jit *jit)
150 {
151 /* Save registers and create stack frame if necessary */
152 if (jit->seen & SEEN_DATAREF) {
153 /* stmg %r8,%r15,88(%r15) */
154 EMIT6(0xeb8ff058, 0x0024);
155 /* lgr %r14,%r15 */
156 EMIT4(0xb90400ef);
157 /* ahi %r15,<offset> */
158 EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80);
159 /* stg %r14,152(%r15) */
160 EMIT6(0xe3e0f098, 0x0024);
161 } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
162 /* stmg %r12,%r13,120(%r15) */
163 EMIT6(0xebcdf078, 0x0024);
164 else if (jit->seen & SEEN_XREG)
165 /* stg %r12,120(%r15) */
166 EMIT6(0xe3c0f078, 0x0024);
167 else if (jit->seen & SEEN_LITERAL)
168 /* stg %r13,128(%r15) */
169 EMIT6(0xe3d0f080, 0x0024);
170
171 /* Setup literal pool */
172 if (jit->seen & SEEN_LITERAL) {
173 /* basr %r13,0 */
174 EMIT2(0x0dd0);
175 jit->base_ip = jit->prg;
176 }
177 jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
178 jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
179 jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
180 jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
181 jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
182 jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
183 jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
184
185 /* Filter needs to access skb data */
186 if (jit->seen & SEEN_DATAREF) {
187 /* l %r11,<len>(%r2) */
188 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
189 /* s %r11,<data_len>(%r2) */
190 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
191 /* lg %r10,<data>(%r2) */
192 EMIT6_DISP(0xe3a02000, 0x0004,
193 offsetof(struct sk_buff, data));
194 }
195 }
196
197 static void bpf_jit_epilogue(struct bpf_jit *jit)
198 {
199 /* Return 0 */
200 if (jit->seen & SEEN_RET0) {
201 jit->ret0_ip = jit->prg;
202 /* lghi %r2,0 */
203 EMIT4(0xa7290000);
204 }
205 jit->exit_ip = jit->prg;
206 /* Restore registers */
207 if (jit->seen & SEEN_DATAREF)
208 /* lmg %r8,%r15,<offset>(%r15) */
209 EMIT6_DISP(0xeb8ff000, 0x0004,
210 (jit->seen & SEEN_MEM) ? 200 : 168);
211 else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
212 /* lmg %r12,%r13,120(%r15) */
213 EMIT6(0xebcdf078, 0x0004);
214 else if (jit->seen & SEEN_XREG)
215 /* lg %r12,120(%r15) */
216 EMIT6(0xe3c0f078, 0x0004);
217 else if (jit->seen & SEEN_LITERAL)
218 /* lg %r13,128(%r15) */
219 EMIT6(0xe3d0f080, 0x0004);
220 /* br %r14 */
221 EMIT2(0x07fe);
222 }
223
224 /*
225 * make sure we dont leak kernel information to user
226 */
227 static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
228 {
229 /* Clear temporary memory if (seen & SEEN_MEM) */
230 if (jit->seen & SEEN_MEM)
231 /* xc 0(64,%r15),0(%r15) */
232 EMIT6(0xd73ff000, 0xf000);
233 /* Clear X if (seen & SEEN_XREG) */
234 if (jit->seen & SEEN_XREG)
235 /* lhi %r12,0 */
236 EMIT4(0xa7c80000);
237 /* Clear A if the first register does not set it. */
238 switch (filter[0].code) {
239 case BPF_S_LD_W_ABS:
240 case BPF_S_LD_H_ABS:
241 case BPF_S_LD_B_ABS:
242 case BPF_S_LD_W_LEN:
243 case BPF_S_LD_W_IND:
244 case BPF_S_LD_H_IND:
245 case BPF_S_LD_B_IND:
246 case BPF_S_LDX_B_MSH:
247 case BPF_S_LD_IMM:
248 case BPF_S_LD_MEM:
249 case BPF_S_MISC_TXA:
250 case BPF_S_ANC_PROTOCOL:
251 case BPF_S_ANC_PKTTYPE:
252 case BPF_S_ANC_IFINDEX:
253 case BPF_S_ANC_MARK:
254 case BPF_S_ANC_QUEUE:
255 case BPF_S_ANC_HATYPE:
256 case BPF_S_ANC_RXHASH:
257 case BPF_S_ANC_CPU:
258 case BPF_S_ANC_VLAN_TAG:
259 case BPF_S_ANC_VLAN_TAG_PRESENT:
260 case BPF_S_RET_K:
261 /* first instruction sets A register */
262 break;
263 default: /* A = 0 */
264 /* lhi %r5,0 */
265 EMIT4(0xa7580000);
266 }
267 }
268
269 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
270 unsigned int *addrs, int i, int last)
271 {
272 unsigned int K;
273 int offset;
274 unsigned int mask;
275
276 K = filter->k;
277 switch (filter->code) {
278 case BPF_S_ALU_ADD_X: /* A += X */
279 jit->seen |= SEEN_XREG;
280 /* ar %r5,%r12 */
281 EMIT2(0x1a5c);
282 break;
283 case BPF_S_ALU_ADD_K: /* A += K */
284 if (!K)
285 break;
286 if (K <= 16383)
287 /* ahi %r5,<K> */
288 EMIT4_IMM(0xa75a0000, K);
289 else if (test_facility(21))
290 /* alfi %r5,<K> */
291 EMIT6_IMM(0xc25b0000, K);
292 else
293 /* a %r5,<d(K)>(%r13) */
294 EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
295 break;
296 case BPF_S_ALU_SUB_X: /* A -= X */
297 jit->seen |= SEEN_XREG;
298 /* sr %r5,%r12 */
299 EMIT2(0x1b5c);
300 break;
301 case BPF_S_ALU_SUB_K: /* A -= K */
302 if (!K)
303 break;
304 if (K <= 16384)
305 /* ahi %r5,-K */
306 EMIT4_IMM(0xa75a0000, -K);
307 else if (test_facility(21))
308 /* alfi %r5,-K */
309 EMIT6_IMM(0xc25b0000, -K);
310 else
311 /* s %r5,<d(K)>(%r13) */
312 EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
313 break;
314 case BPF_S_ALU_MUL_X: /* A *= X */
315 jit->seen |= SEEN_XREG;
316 /* msr %r5,%r12 */
317 EMIT4(0xb252005c);
318 break;
319 case BPF_S_ALU_MUL_K: /* A *= K */
320 if (K <= 16383)
321 /* mhi %r5,K */
322 EMIT4_IMM(0xa75c0000, K);
323 else if (test_facility(34))
324 /* msfi %r5,<K> */
325 EMIT6_IMM(0xc2510000, K);
326 else
327 /* ms %r5,<d(K)>(%r13) */
328 EMIT4_DISP(0x7150d000, EMIT_CONST(K));
329 break;
330 case BPF_S_ALU_DIV_X: /* A /= X */
331 jit->seen |= SEEN_XREG | SEEN_RET0;
332 /* ltr %r12,%r12 */
333 EMIT2(0x12cc);
334 /* jz <ret0> */
335 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
336 /* lhi %r4,0 */
337 EMIT4(0xa7480000);
338 /* dr %r4,%r12 */
339 EMIT2(0x1d4c);
340 break;
341 case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
342 /* m %r4,<d(K)>(%r13) */
343 EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
344 /* lr %r5,%r4 */
345 EMIT2(0x1854);
346 break;
347 case BPF_S_ALU_MOD_X: /* A %= X */
348 jit->seen |= SEEN_XREG | SEEN_RET0;
349 /* ltr %r12,%r12 */
350 EMIT2(0x12cc);
351 /* jz <ret0> */
352 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
353 /* lhi %r4,0 */
354 EMIT4(0xa7480000);
355 /* dr %r4,%r12 */
356 EMIT2(0x1d4c);
357 /* lr %r5,%r4 */
358 EMIT2(0x1854);
359 break;
360 case BPF_S_ALU_MOD_K: /* A %= K */
361 /* lhi %r4,0 */
362 EMIT4(0xa7480000);
363 /* d %r4,<d(K)>(%r13) */
364 EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
365 /* lr %r5,%r4 */
366 EMIT2(0x1854);
367 break;
368 case BPF_S_ALU_AND_X: /* A &= X */
369 jit->seen |= SEEN_XREG;
370 /* nr %r5,%r12 */
371 EMIT2(0x145c);
372 break;
373 case BPF_S_ALU_AND_K: /* A &= K */
374 if (test_facility(21))
375 /* nilf %r5,<K> */
376 EMIT6_IMM(0xc05b0000, K);
377 else
378 /* n %r5,<d(K)>(%r13) */
379 EMIT4_DISP(0x5450d000, EMIT_CONST(K));
380 break;
381 case BPF_S_ALU_OR_X: /* A |= X */
382 jit->seen |= SEEN_XREG;
383 /* or %r5,%r12 */
384 EMIT2(0x165c);
385 break;
386 case BPF_S_ALU_OR_K: /* A |= K */
387 if (test_facility(21))
388 /* oilf %r5,<K> */
389 EMIT6_IMM(0xc05d0000, K);
390 else
391 /* o %r5,<d(K)>(%r13) */
392 EMIT4_DISP(0x5650d000, EMIT_CONST(K));
393 break;
394 case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
395 case BPF_S_ALU_XOR_X:
396 jit->seen |= SEEN_XREG;
397 /* xr %r5,%r12 */
398 EMIT2(0x175c);
399 break;
400 case BPF_S_ALU_XOR_K: /* A ^= K */
401 if (!K)
402 break;
403 /* x %r5,<d(K)>(%r13) */
404 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
405 break;
406 case BPF_S_ALU_LSH_X: /* A <<= X; */
407 jit->seen |= SEEN_XREG;
408 /* sll %r5,0(%r12) */
409 EMIT4(0x8950c000);
410 break;
411 case BPF_S_ALU_LSH_K: /* A <<= K */
412 if (K == 0)
413 break;
414 /* sll %r5,K */
415 EMIT4_DISP(0x89500000, K);
416 break;
417 case BPF_S_ALU_RSH_X: /* A >>= X; */
418 jit->seen |= SEEN_XREG;
419 /* srl %r5,0(%r12) */
420 EMIT4(0x8850c000);
421 break;
422 case BPF_S_ALU_RSH_K: /* A >>= K; */
423 if (K == 0)
424 break;
425 /* srl %r5,K */
426 EMIT4_DISP(0x88500000, K);
427 break;
428 case BPF_S_ALU_NEG: /* A = -A */
429 /* lnr %r5,%r5 */
430 EMIT2(0x1155);
431 break;
432 case BPF_S_JMP_JA: /* ip += K */
433 offset = addrs[i + K] + jit->start - jit->prg;
434 EMIT4_PCREL(0xa7f40000, offset);
435 break;
436 case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
437 mask = 0x200000; /* jh */
438 goto kbranch;
439 case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
440 mask = 0xa00000; /* jhe */
441 goto kbranch;
442 case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
443 mask = 0x800000; /* je */
444 kbranch: /* Emit compare if the branch targets are different */
445 if (filter->jt != filter->jf) {
446 if (K <= 16383)
447 /* chi %r5,<K> */
448 EMIT4_IMM(0xa75e0000, K);
449 else if (test_facility(21))
450 /* clfi %r5,<K> */
451 EMIT6_IMM(0xc25f0000, K);
452 else
453 /* c %r5,<d(K)>(%r13) */
454 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
455 }
456 branch: if (filter->jt == filter->jf) {
457 if (filter->jt == 0)
458 break;
459 /* j <jt> */
460 offset = addrs[i + filter->jt] + jit->start - jit->prg;
461 EMIT4_PCREL(0xa7f40000, offset);
462 break;
463 }
464 if (filter->jt != 0) {
465 /* brc <mask>,<jt> */
466 offset = addrs[i + filter->jt] + jit->start - jit->prg;
467 EMIT4_PCREL(0xa7040000 | mask, offset);
468 }
469 if (filter->jf != 0) {
470 /* brc <mask^15>,<jf> */
471 offset = addrs[i + filter->jf] + jit->start - jit->prg;
472 EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
473 }
474 break;
475 case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
476 mask = 0x700000; /* jnz */
477 /* Emit test if the branch targets are different */
478 if (filter->jt != filter->jf) {
479 if (K > 65535) {
480 /* lr %r4,%r5 */
481 EMIT2(0x1845);
482 /* n %r4,<d(K)>(%r13) */
483 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
484 } else
485 /* tmll %r5,K */
486 EMIT4_IMM(0xa7510000, K);
487 }
488 goto branch;
489 case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
490 mask = 0x200000; /* jh */
491 goto xbranch;
492 case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
493 mask = 0xa00000; /* jhe */
494 goto xbranch;
495 case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
496 mask = 0x800000; /* je */
497 xbranch: /* Emit compare if the branch targets are different */
498 if (filter->jt != filter->jf) {
499 jit->seen |= SEEN_XREG;
500 /* cr %r5,%r12 */
501 EMIT2(0x195c);
502 }
503 goto branch;
504 case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
505 mask = 0x700000; /* jnz */
506 /* Emit test if the branch targets are different */
507 if (filter->jt != filter->jf) {
508 jit->seen |= SEEN_XREG;
509 /* lr %r4,%r5 */
510 EMIT2(0x1845);
511 /* nr %r4,%r12 */
512 EMIT2(0x144c);
513 }
514 goto branch;
515 case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
516 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
517 offset = jit->off_load_word;
518 goto load_abs;
519 case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
520 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
521 offset = jit->off_load_half;
522 goto load_abs;
523 case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
524 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
525 offset = jit->off_load_byte;
526 load_abs: if ((int) K < 0)
527 goto out;
528 call_fn: /* lg %r1,<d(function)>(%r13) */
529 EMIT6_DISP(0xe310d000, 0x0004, offset);
530 /* l %r3,<d(K)>(%r13) */
531 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
532 /* basr %r8,%r1 */
533 EMIT2(0x0d81);
534 /* jnz <ret0> */
535 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
536 break;
537 case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
538 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
539 offset = jit->off_load_iword;
540 goto call_fn;
541 case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
542 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
543 offset = jit->off_load_ihalf;
544 goto call_fn;
545 case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
546 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
547 offset = jit->off_load_ibyte;
548 goto call_fn;
549 case BPF_S_LDX_B_MSH:
550 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
551 jit->seen |= SEEN_RET0;
552 if ((int) K < 0) {
553 /* j <ret0> */
554 EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
555 break;
556 }
557 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
558 offset = jit->off_load_bmsh;
559 goto call_fn;
560 case BPF_S_LD_W_LEN: /* A = skb->len; */
561 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
562 /* l %r5,<d(len)>(%r2) */
563 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
564 break;
565 case BPF_S_LDX_W_LEN: /* X = skb->len; */
566 jit->seen |= SEEN_XREG;
567 /* l %r12,<d(len)>(%r2) */
568 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
569 break;
570 case BPF_S_LD_IMM: /* A = K */
571 if (K <= 16383)
572 /* lhi %r5,K */
573 EMIT4_IMM(0xa7580000, K);
574 else if (test_facility(21))
575 /* llilf %r5,<K> */
576 EMIT6_IMM(0xc05f0000, K);
577 else
578 /* l %r5,<d(K)>(%r13) */
579 EMIT4_DISP(0x5850d000, EMIT_CONST(K));
580 break;
581 case BPF_S_LDX_IMM: /* X = K */
582 jit->seen |= SEEN_XREG;
583 if (K <= 16383)
584 /* lhi %r12,<K> */
585 EMIT4_IMM(0xa7c80000, K);
586 else if (test_facility(21))
587 /* llilf %r12,<K> */
588 EMIT6_IMM(0xc0cf0000, K);
589 else
590 /* l %r12,<d(K)>(%r13) */
591 EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
592 break;
593 case BPF_S_LD_MEM: /* A = mem[K] */
594 jit->seen |= SEEN_MEM;
595 /* l %r5,<K>(%r15) */
596 EMIT4_DISP(0x5850f000,
597 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
598 break;
599 case BPF_S_LDX_MEM: /* X = mem[K] */
600 jit->seen |= SEEN_XREG | SEEN_MEM;
601 /* l %r12,<K>(%r15) */
602 EMIT4_DISP(0x58c0f000,
603 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
604 break;
605 case BPF_S_MISC_TAX: /* X = A */
606 jit->seen |= SEEN_XREG;
607 /* lr %r12,%r5 */
608 EMIT2(0x18c5);
609 break;
610 case BPF_S_MISC_TXA: /* A = X */
611 jit->seen |= SEEN_XREG;
612 /* lr %r5,%r12 */
613 EMIT2(0x185c);
614 break;
615 case BPF_S_RET_K:
616 if (K == 0) {
617 jit->seen |= SEEN_RET0;
618 if (last)
619 break;
620 /* j <ret0> */
621 EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
622 } else {
623 if (K <= 16383)
624 /* lghi %r2,K */
625 EMIT4_IMM(0xa7290000, K);
626 else
627 /* llgf %r2,<K>(%r13) */
628 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
629 /* j <exit> */
630 if (last && !(jit->seen & SEEN_RET0))
631 break;
632 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
633 }
634 break;
635 case BPF_S_RET_A:
636 /* llgfr %r2,%r5 */
637 EMIT4(0xb9160025);
638 /* j <exit> */
639 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
640 break;
641 case BPF_S_ST: /* mem[K] = A */
642 jit->seen |= SEEN_MEM;
643 /* st %r5,<K>(%r15) */
644 EMIT4_DISP(0x5050f000,
645 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
646 break;
647 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
648 jit->seen |= SEEN_XREG | SEEN_MEM;
649 /* st %r12,<K>(%r15) */
650 EMIT4_DISP(0x50c0f000,
651 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
652 break;
653 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
654 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
655 /* lhi %r5,0 */
656 EMIT4(0xa7580000);
657 /* icm %r5,3,<d(protocol)>(%r2) */
658 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
659 break;
660 case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
661 * A = skb->dev->ifindex */
662 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
663 jit->seen |= SEEN_RET0;
664 /* lg %r1,<d(dev)>(%r2) */
665 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
666 /* ltgr %r1,%r1 */
667 EMIT4(0xb9020011);
668 /* jz <ret0> */
669 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
670 /* l %r5,<d(ifindex)>(%r1) */
671 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
672 break;
673 case BPF_S_ANC_MARK: /* A = skb->mark */
674 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
675 /* l %r5,<d(mark)>(%r2) */
676 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
677 break;
678 case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
679 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
680 /* lhi %r5,0 */
681 EMIT4(0xa7580000);
682 /* icm %r5,3,<d(queue_mapping)>(%r2) */
683 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
684 break;
685 case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0;
686 * A = skb->dev->type */
687 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
688 jit->seen |= SEEN_RET0;
689 /* lg %r1,<d(dev)>(%r2) */
690 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
691 /* ltgr %r1,%r1 */
692 EMIT4(0xb9020011);
693 /* jz <ret0> */
694 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
695 /* lhi %r5,0 */
696 EMIT4(0xa7580000);
697 /* icm %r5,3,<d(type)>(%r1) */
698 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
699 break;
700 case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
701 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
702 /* l %r5,<d(rxhash)>(%r2) */
703 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
704 break;
705 case BPF_S_ANC_VLAN_TAG:
706 case BPF_S_ANC_VLAN_TAG_PRESENT:
707 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
708 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
709 /* lhi %r5,0 */
710 EMIT4(0xa7580000);
711 /* icm %r5,3,<d(vlan_tci)>(%r2) */
712 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
713 if (filter->code == BPF_S_ANC_VLAN_TAG) {
714 /* nill %r5,0xefff */
715 EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
716 } else {
717 /* nill %r5,0x1000 */
718 EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
719 /* srl %r5,12 */
720 EMIT4_DISP(0x88500000, 12);
721 }
722 break;
723 case BPF_S_ANC_CPU: /* A = smp_processor_id() */
724 #ifdef CONFIG_SMP
725 /* l %r5,<d(cpu_nr)> */
726 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
727 #else
728 /* lhi %r5,0 */
729 EMIT4(0xa7580000);
730 #endif
731 break;
732 default: /* too complex, give up */
733 goto out;
734 }
735 addrs[i] = jit->prg - jit->start;
736 return 0;
737 out:
738 return -1;
739 }
740
741 void bpf_jit_compile(struct sk_filter *fp)
742 {
743 unsigned long size, prg_len, lit_len;
744 struct bpf_jit jit, cjit;
745 unsigned int *addrs;
746 int pass, i;
747
748 if (!bpf_jit_enable)
749 return;
750 addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
751 if (addrs == NULL)
752 return;
753 memset(&jit, 0, sizeof(cjit));
754 memset(&cjit, 0, sizeof(cjit));
755
756 for (pass = 0; pass < 10; pass++) {
757 jit.prg = jit.start;
758 jit.lit = jit.mid;
759
760 bpf_jit_prologue(&jit);
761 bpf_jit_noleaks(&jit, fp->insns);
762 for (i = 0; i < fp->len; i++) {
763 if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
764 i == fp->len - 1))
765 goto out;
766 }
767 bpf_jit_epilogue(&jit);
768 if (jit.start) {
769 WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
770 if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
771 break;
772 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
773 prg_len = jit.prg - jit.start;
774 lit_len = jit.lit - jit.mid;
775 size = max_t(unsigned long, prg_len + lit_len,
776 sizeof(struct work_struct));
777 if (size >= BPF_SIZE_MAX)
778 goto out;
779 jit.start = module_alloc(size);
780 if (!jit.start)
781 goto out;
782 jit.prg = jit.mid = jit.start + prg_len;
783 jit.lit = jit.end = jit.start + prg_len + lit_len;
784 jit.base_ip += (unsigned long) jit.start;
785 jit.exit_ip += (unsigned long) jit.start;
786 jit.ret0_ip += (unsigned long) jit.start;
787 }
788 cjit = jit;
789 }
790 if (bpf_jit_enable > 1) {
791 pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
792 fp->len, jit.end - jit.start, pass, jit.start);
793 if (jit.start) {
794 printk(KERN_ERR "JIT code:\n");
795 print_fn_code(jit.start, jit.mid - jit.start);
796 print_hex_dump(KERN_ERR, "JIT literals:\n",
797 DUMP_PREFIX_ADDRESS, 16, 1,
798 jit.mid, jit.end - jit.mid, false);
799 }
800 }
801 if (jit.start)
802 fp->bpf_func = (void *) jit.start;
803 out:
804 kfree(addrs);
805 }
806
807 static void jit_free_defer(struct work_struct *arg)
808 {
809 module_free(NULL, arg);
810 }
811
812 /* run from softirq, we must use a work_struct to call
813 * module_free() from process context
814 */
815 void bpf_jit_free(struct sk_filter *fp)
816 {
817 struct work_struct *work;
818
819 if (fp->bpf_func == sk_run_filter)
820 return;
821 work = (struct work_struct *)fp->bpf_func;
822 INIT_WORK(work, jit_free_defer);
823 schedule_work(work);
824 }
Linux kernel - Deliverables
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