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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
[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/netdevice.h>
9 #include <linux/if_vlan.h>
10 #include <linux/filter.h>
11 #include <linux/init.h>
12 #include <asm/cacheflush.h>
13 #include <asm/facility.h>
14 #include <asm/dis.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_fill_hole(void *area, unsigned int size)
150 {
151 /* Fill whole space with illegal instructions */
152 memset(area, 0, size);
153 }
154
155 static void bpf_jit_prologue(struct bpf_jit *jit)
156 {
157 /* Save registers and create stack frame if necessary */
158 if (jit->seen & SEEN_DATAREF) {
159 /* stmg %r8,%r15,88(%r15) */
160 EMIT6(0xeb8ff058, 0x0024);
161 /* lgr %r14,%r15 */
162 EMIT4(0xb90400ef);
163 /* aghi %r15,<offset> */
164 EMIT4_IMM(0xa7fb0000, (jit->seen & SEEN_MEM) ? -112 : -80);
165 /* stg %r14,152(%r15) */
166 EMIT6(0xe3e0f098, 0x0024);
167 } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
168 /* stmg %r12,%r13,120(%r15) */
169 EMIT6(0xebcdf078, 0x0024);
170 else if (jit->seen & SEEN_XREG)
171 /* stg %r12,120(%r15) */
172 EMIT6(0xe3c0f078, 0x0024);
173 else if (jit->seen & SEEN_LITERAL)
174 /* stg %r13,128(%r15) */
175 EMIT6(0xe3d0f080, 0x0024);
176
177 /* Setup literal pool */
178 if (jit->seen & SEEN_LITERAL) {
179 /* basr %r13,0 */
180 EMIT2(0x0dd0);
181 jit->base_ip = jit->prg;
182 }
183 jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
184 jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
185 jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
186 jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
187 jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
188 jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
189 jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
190
191 /* Filter needs to access skb data */
192 if (jit->seen & SEEN_DATAREF) {
193 /* l %r11,<len>(%r2) */
194 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
195 /* s %r11,<data_len>(%r2) */
196 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
197 /* lg %r10,<data>(%r2) */
198 EMIT6_DISP(0xe3a02000, 0x0004,
199 offsetof(struct sk_buff, data));
200 }
201 }
202
203 static void bpf_jit_epilogue(struct bpf_jit *jit)
204 {
205 /* Return 0 */
206 if (jit->seen & SEEN_RET0) {
207 jit->ret0_ip = jit->prg;
208 /* lghi %r2,0 */
209 EMIT4(0xa7290000);
210 }
211 jit->exit_ip = jit->prg;
212 /* Restore registers */
213 if (jit->seen & SEEN_DATAREF)
214 /* lmg %r8,%r15,<offset>(%r15) */
215 EMIT6_DISP(0xeb8ff000, 0x0004,
216 (jit->seen & SEEN_MEM) ? 200 : 168);
217 else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
218 /* lmg %r12,%r13,120(%r15) */
219 EMIT6(0xebcdf078, 0x0004);
220 else if (jit->seen & SEEN_XREG)
221 /* lg %r12,120(%r15) */
222 EMIT6(0xe3c0f078, 0x0004);
223 else if (jit->seen & SEEN_LITERAL)
224 /* lg %r13,128(%r15) */
225 EMIT6(0xe3d0f080, 0x0004);
226 /* br %r14 */
227 EMIT2(0x07fe);
228 }
229
230 /*
231 * make sure we dont leak kernel information to user
232 */
233 static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
234 {
235 /* Clear temporary memory if (seen & SEEN_MEM) */
236 if (jit->seen & SEEN_MEM)
237 /* xc 0(64,%r15),0(%r15) */
238 EMIT6(0xd73ff000, 0xf000);
239 /* Clear X if (seen & SEEN_XREG) */
240 if (jit->seen & SEEN_XREG)
241 /* lhi %r12,0 */
242 EMIT4(0xa7c80000);
243 /* Clear A if the first register does not set it. */
244 switch (filter[0].code) {
245 case BPF_LD | BPF_W | BPF_ABS:
246 case BPF_LD | BPF_H | BPF_ABS:
247 case BPF_LD | BPF_B | BPF_ABS:
248 case BPF_LD | BPF_W | BPF_LEN:
249 case BPF_LD | BPF_W | BPF_IND:
250 case BPF_LD | BPF_H | BPF_IND:
251 case BPF_LD | BPF_B | BPF_IND:
252 case BPF_LD | BPF_IMM:
253 case BPF_LD | BPF_MEM:
254 case BPF_MISC | BPF_TXA:
255 case BPF_RET | BPF_K:
256 /* first instruction sets A register */
257 break;
258 default: /* A = 0 */
259 /* lhi %r5,0 */
260 EMIT4(0xa7580000);
261 }
262 }
263
264 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
265 unsigned int *addrs, int i, int last)
266 {
267 unsigned int K;
268 int offset;
269 unsigned int mask;
270 u16 code;
271
272 K = filter->k;
273 code = bpf_anc_helper(filter);
274
275 switch (code) {
276 case BPF_ALU | BPF_ADD | BPF_X: /* A += X */
277 jit->seen |= SEEN_XREG;
278 /* ar %r5,%r12 */
279 EMIT2(0x1a5c);
280 break;
281 case BPF_ALU | BPF_ADD | BPF_K: /* A += K */
282 if (!K)
283 break;
284 if (K <= 16383)
285 /* ahi %r5,<K> */
286 EMIT4_IMM(0xa75a0000, K);
287 else if (test_facility(21))
288 /* alfi %r5,<K> */
289 EMIT6_IMM(0xc25b0000, K);
290 else
291 /* a %r5,<d(K)>(%r13) */
292 EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
293 break;
294 case BPF_ALU | BPF_SUB | BPF_X: /* A -= X */
295 jit->seen |= SEEN_XREG;
296 /* sr %r5,%r12 */
297 EMIT2(0x1b5c);
298 break;
299 case BPF_ALU | BPF_SUB | BPF_K: /* A -= K */
300 if (!K)
301 break;
302 if (K <= 16384)
303 /* ahi %r5,-K */
304 EMIT4_IMM(0xa75a0000, -K);
305 else if (test_facility(21))
306 /* alfi %r5,-K */
307 EMIT6_IMM(0xc25b0000, -K);
308 else
309 /* s %r5,<d(K)>(%r13) */
310 EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
311 break;
312 case BPF_ALU | BPF_MUL | BPF_X: /* A *= X */
313 jit->seen |= SEEN_XREG;
314 /* msr %r5,%r12 */
315 EMIT4(0xb252005c);
316 break;
317 case BPF_ALU | BPF_MUL | BPF_K: /* A *= K */
318 if (K <= 16383)
319 /* mhi %r5,K */
320 EMIT4_IMM(0xa75c0000, K);
321 else if (test_facility(34))
322 /* msfi %r5,<K> */
323 EMIT6_IMM(0xc2510000, K);
324 else
325 /* ms %r5,<d(K)>(%r13) */
326 EMIT4_DISP(0x7150d000, EMIT_CONST(K));
327 break;
328 case BPF_ALU | BPF_DIV | BPF_X: /* A /= X */
329 jit->seen |= SEEN_XREG | SEEN_RET0;
330 /* ltr %r12,%r12 */
331 EMIT2(0x12cc);
332 /* jz <ret0> */
333 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
334 /* lhi %r4,0 */
335 EMIT4(0xa7480000);
336 /* dlr %r4,%r12 */
337 EMIT4(0xb997004c);
338 break;
339 case BPF_ALU | BPF_DIV | BPF_K: /* A /= K */
340 if (K == 1)
341 break;
342 /* lhi %r4,0 */
343 EMIT4(0xa7480000);
344 /* dl %r4,<d(K)>(%r13) */
345 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
346 break;
347 case BPF_ALU | BPF_MOD | BPF_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 /* dlr %r4,%r12 */
356 EMIT4(0xb997004c);
357 /* lr %r5,%r4 */
358 EMIT2(0x1854);
359 break;
360 case BPF_ALU | BPF_MOD | BPF_K: /* A %= K */
361 if (K == 1) {
362 /* lhi %r5,0 */
363 EMIT4(0xa7580000);
364 break;
365 }
366 /* lhi %r4,0 */
367 EMIT4(0xa7480000);
368 /* dl %r4,<d(K)>(%r13) */
369 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
370 /* lr %r5,%r4 */
371 EMIT2(0x1854);
372 break;
373 case BPF_ALU | BPF_AND | BPF_X: /* A &= X */
374 jit->seen |= SEEN_XREG;
375 /* nr %r5,%r12 */
376 EMIT2(0x145c);
377 break;
378 case BPF_ALU | BPF_AND | BPF_K: /* A &= K */
379 if (test_facility(21))
380 /* nilf %r5,<K> */
381 EMIT6_IMM(0xc05b0000, K);
382 else
383 /* n %r5,<d(K)>(%r13) */
384 EMIT4_DISP(0x5450d000, EMIT_CONST(K));
385 break;
386 case BPF_ALU | BPF_OR | BPF_X: /* A |= X */
387 jit->seen |= SEEN_XREG;
388 /* or %r5,%r12 */
389 EMIT2(0x165c);
390 break;
391 case BPF_ALU | BPF_OR | BPF_K: /* A |= K */
392 if (test_facility(21))
393 /* oilf %r5,<K> */
394 EMIT6_IMM(0xc05d0000, K);
395 else
396 /* o %r5,<d(K)>(%r13) */
397 EMIT4_DISP(0x5650d000, EMIT_CONST(K));
398 break;
399 case BPF_ANC | SKF_AD_ALU_XOR_X: /* A ^= X; */
400 case BPF_ALU | BPF_XOR | BPF_X:
401 jit->seen |= SEEN_XREG;
402 /* xr %r5,%r12 */
403 EMIT2(0x175c);
404 break;
405 case BPF_ALU | BPF_XOR | BPF_K: /* A ^= K */
406 if (!K)
407 break;
408 /* x %r5,<d(K)>(%r13) */
409 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
410 break;
411 case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X; */
412 jit->seen |= SEEN_XREG;
413 /* sll %r5,0(%r12) */
414 EMIT4(0x8950c000);
415 break;
416 case BPF_ALU | BPF_LSH | BPF_K: /* A <<= K */
417 if (K == 0)
418 break;
419 /* sll %r5,K */
420 EMIT4_DISP(0x89500000, K);
421 break;
422 case BPF_ALU | BPF_RSH | BPF_X: /* A >>= X; */
423 jit->seen |= SEEN_XREG;
424 /* srl %r5,0(%r12) */
425 EMIT4(0x8850c000);
426 break;
427 case BPF_ALU | BPF_RSH | BPF_K: /* A >>= K; */
428 if (K == 0)
429 break;
430 /* srl %r5,K */
431 EMIT4_DISP(0x88500000, K);
432 break;
433 case BPF_ALU | BPF_NEG: /* A = -A */
434 /* lcr %r5,%r5 */
435 EMIT2(0x1355);
436 break;
437 case BPF_JMP | BPF_JA: /* ip += K */
438 offset = addrs[i + K] + jit->start - jit->prg;
439 EMIT4_PCREL(0xa7f40000, offset);
440 break;
441 case BPF_JMP | BPF_JGT | BPF_K: /* ip += (A > K) ? jt : jf */
442 mask = 0x200000; /* jh */
443 goto kbranch;
444 case BPF_JMP | BPF_JGE | BPF_K: /* ip += (A >= K) ? jt : jf */
445 mask = 0xa00000; /* jhe */
446 goto kbranch;
447 case BPF_JMP | BPF_JEQ | BPF_K: /* ip += (A == K) ? jt : jf */
448 mask = 0x800000; /* je */
449 kbranch: /* Emit compare if the branch targets are different */
450 if (filter->jt != filter->jf) {
451 if (K <= 16383)
452 /* chi %r5,<K> */
453 EMIT4_IMM(0xa75e0000, K);
454 else if (test_facility(21))
455 /* clfi %r5,<K> */
456 EMIT6_IMM(0xc25f0000, K);
457 else
458 /* c %r5,<d(K)>(%r13) */
459 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
460 }
461 branch: if (filter->jt == filter->jf) {
462 if (filter->jt == 0)
463 break;
464 /* j <jt> */
465 offset = addrs[i + filter->jt] + jit->start - jit->prg;
466 EMIT4_PCREL(0xa7f40000, offset);
467 break;
468 }
469 if (filter->jt != 0) {
470 /* brc <mask>,<jt> */
471 offset = addrs[i + filter->jt] + jit->start - jit->prg;
472 EMIT4_PCREL(0xa7040000 | mask, offset);
473 }
474 if (filter->jf != 0) {
475 /* brc <mask^15>,<jf> */
476 offset = addrs[i + filter->jf] + jit->start - jit->prg;
477 EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
478 }
479 break;
480 case BPF_JMP | BPF_JSET | BPF_K: /* ip += (A & K) ? jt : jf */
481 mask = 0x700000; /* jnz */
482 /* Emit test if the branch targets are different */
483 if (filter->jt != filter->jf) {
484 if (K > 65535) {
485 /* lr %r4,%r5 */
486 EMIT2(0x1845);
487 /* n %r4,<d(K)>(%r13) */
488 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
489 } else
490 /* tmll %r5,K */
491 EMIT4_IMM(0xa7510000, K);
492 }
493 goto branch;
494 case BPF_JMP | BPF_JGT | BPF_X: /* ip += (A > X) ? jt : jf */
495 mask = 0x200000; /* jh */
496 goto xbranch;
497 case BPF_JMP | BPF_JGE | BPF_X: /* ip += (A >= X) ? jt : jf */
498 mask = 0xa00000; /* jhe */
499 goto xbranch;
500 case BPF_JMP | BPF_JEQ | BPF_X: /* ip += (A == X) ? jt : jf */
501 mask = 0x800000; /* je */
502 xbranch: /* Emit compare if the branch targets are different */
503 if (filter->jt != filter->jf) {
504 jit->seen |= SEEN_XREG;
505 /* clr %r5,%r12 */
506 EMIT2(0x155c);
507 }
508 goto branch;
509 case BPF_JMP | BPF_JSET | BPF_X: /* ip += (A & X) ? jt : jf */
510 mask = 0x700000; /* jnz */
511 /* Emit test if the branch targets are different */
512 if (filter->jt != filter->jf) {
513 jit->seen |= SEEN_XREG;
514 /* lr %r4,%r5 */
515 EMIT2(0x1845);
516 /* nr %r4,%r12 */
517 EMIT2(0x144c);
518 }
519 goto branch;
520 case BPF_LD | BPF_W | BPF_ABS: /* A = *(u32 *) (skb->data+K) */
521 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
522 offset = jit->off_load_word;
523 goto load_abs;
524 case BPF_LD | BPF_H | BPF_ABS: /* A = *(u16 *) (skb->data+K) */
525 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
526 offset = jit->off_load_half;
527 goto load_abs;
528 case BPF_LD | BPF_B | BPF_ABS: /* A = *(u8 *) (skb->data+K) */
529 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
530 offset = jit->off_load_byte;
531 load_abs: if ((int) K < 0)
532 goto out;
533 call_fn: /* lg %r1,<d(function)>(%r13) */
534 EMIT6_DISP(0xe310d000, 0x0004, offset);
535 /* l %r3,<d(K)>(%r13) */
536 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
537 /* basr %r8,%r1 */
538 EMIT2(0x0d81);
539 /* jnz <ret0> */
540 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
541 break;
542 case BPF_LD | BPF_W | BPF_IND: /* A = *(u32 *) (skb->data+K+X) */
543 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
544 offset = jit->off_load_iword;
545 goto call_fn;
546 case BPF_LD | BPF_H | BPF_IND: /* A = *(u16 *) (skb->data+K+X) */
547 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
548 offset = jit->off_load_ihalf;
549 goto call_fn;
550 case BPF_LD | BPF_B | BPF_IND: /* A = *(u8 *) (skb->data+K+X) */
551 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
552 offset = jit->off_load_ibyte;
553 goto call_fn;
554 case BPF_LDX | BPF_B | BPF_MSH:
555 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
556 jit->seen |= SEEN_RET0;
557 if ((int) K < 0) {
558 /* j <ret0> */
559 EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
560 break;
561 }
562 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
563 offset = jit->off_load_bmsh;
564 goto call_fn;
565 case BPF_LD | BPF_W | BPF_LEN: /* A = skb->len; */
566 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
567 /* l %r5,<d(len)>(%r2) */
568 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
569 break;
570 case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
571 jit->seen |= SEEN_XREG;
572 /* l %r12,<d(len)>(%r2) */
573 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
574 break;
575 case BPF_LD | BPF_IMM: /* A = K */
576 if (K <= 16383)
577 /* lhi %r5,K */
578 EMIT4_IMM(0xa7580000, K);
579 else if (test_facility(21))
580 /* llilf %r5,<K> */
581 EMIT6_IMM(0xc05f0000, K);
582 else
583 /* l %r5,<d(K)>(%r13) */
584 EMIT4_DISP(0x5850d000, EMIT_CONST(K));
585 break;
586 case BPF_LDX | BPF_IMM: /* X = K */
587 jit->seen |= SEEN_XREG;
588 if (K <= 16383)
589 /* lhi %r12,<K> */
590 EMIT4_IMM(0xa7c80000, K);
591 else if (test_facility(21))
592 /* llilf %r12,<K> */
593 EMIT6_IMM(0xc0cf0000, K);
594 else
595 /* l %r12,<d(K)>(%r13) */
596 EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
597 break;
598 case BPF_LD | BPF_MEM: /* A = mem[K] */
599 jit->seen |= SEEN_MEM;
600 /* l %r5,<K>(%r15) */
601 EMIT4_DISP(0x5850f000,
602 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
603 break;
604 case BPF_LDX | BPF_MEM: /* X = mem[K] */
605 jit->seen |= SEEN_XREG | SEEN_MEM;
606 /* l %r12,<K>(%r15) */
607 EMIT4_DISP(0x58c0f000,
608 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
609 break;
610 case BPF_MISC | BPF_TAX: /* X = A */
611 jit->seen |= SEEN_XREG;
612 /* lr %r12,%r5 */
613 EMIT2(0x18c5);
614 break;
615 case BPF_MISC | BPF_TXA: /* A = X */
616 jit->seen |= SEEN_XREG;
617 /* lr %r5,%r12 */
618 EMIT2(0x185c);
619 break;
620 case BPF_RET | BPF_K:
621 if (K == 0) {
622 jit->seen |= SEEN_RET0;
623 if (last)
624 break;
625 /* j <ret0> */
626 EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
627 } else {
628 if (K <= 16383)
629 /* lghi %r2,K */
630 EMIT4_IMM(0xa7290000, K);
631 else
632 /* llgf %r2,<K>(%r13) */
633 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
634 /* j <exit> */
635 if (last && !(jit->seen & SEEN_RET0))
636 break;
637 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
638 }
639 break;
640 case BPF_RET | BPF_A:
641 /* llgfr %r2,%r5 */
642 EMIT4(0xb9160025);
643 /* j <exit> */
644 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
645 break;
646 case BPF_ST: /* mem[K] = A */
647 jit->seen |= SEEN_MEM;
648 /* st %r5,<K>(%r15) */
649 EMIT4_DISP(0x5050f000,
650 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
651 break;
652 case BPF_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
653 jit->seen |= SEEN_XREG | SEEN_MEM;
654 /* st %r12,<K>(%r15) */
655 EMIT4_DISP(0x50c0f000,
656 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
657 break;
658 case BPF_ANC | SKF_AD_PROTOCOL: /* A = ntohs(skb->protocol); */
659 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
660 /* lhi %r5,0 */
661 EMIT4(0xa7580000);
662 /* icm %r5,3,<d(protocol)>(%r2) */
663 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
664 break;
665 case BPF_ANC | SKF_AD_IFINDEX: /* if (!skb->dev) return 0;
666 * A = skb->dev->ifindex */
667 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
668 jit->seen |= SEEN_RET0;
669 /* lg %r1,<d(dev)>(%r2) */
670 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
671 /* ltgr %r1,%r1 */
672 EMIT4(0xb9020011);
673 /* jz <ret0> */
674 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
675 /* l %r5,<d(ifindex)>(%r1) */
676 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
677 break;
678 case BPF_ANC | SKF_AD_MARK: /* A = skb->mark */
679 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
680 /* l %r5,<d(mark)>(%r2) */
681 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
682 break;
683 case BPF_ANC | SKF_AD_QUEUE: /* A = skb->queue_mapping */
684 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
685 /* lhi %r5,0 */
686 EMIT4(0xa7580000);
687 /* icm %r5,3,<d(queue_mapping)>(%r2) */
688 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
689 break;
690 case BPF_ANC | SKF_AD_HATYPE: /* if (!skb->dev) return 0;
691 * A = skb->dev->type */
692 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
693 jit->seen |= SEEN_RET0;
694 /* lg %r1,<d(dev)>(%r2) */
695 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
696 /* ltgr %r1,%r1 */
697 EMIT4(0xb9020011);
698 /* jz <ret0> */
699 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
700 /* lhi %r5,0 */
701 EMIT4(0xa7580000);
702 /* icm %r5,3,<d(type)>(%r1) */
703 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
704 break;
705 case BPF_ANC | SKF_AD_RXHASH: /* A = skb->hash */
706 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
707 /* l %r5,<d(hash)>(%r2) */
708 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, hash));
709 break;
710 case BPF_ANC | SKF_AD_VLAN_TAG:
711 case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
712 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
713 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
714 /* lhi %r5,0 */
715 EMIT4(0xa7580000);
716 /* icm %r5,3,<d(vlan_tci)>(%r2) */
717 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
718 if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
719 /* nill %r5,0xefff */
720 EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
721 } else {
722 /* nill %r5,0x1000 */
723 EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
724 /* srl %r5,12 */
725 EMIT4_DISP(0x88500000, 12);
726 }
727 break;
728 case BPF_ANC | SKF_AD_PKTTYPE:
729 /* lhi %r5,0 */
730 EMIT4(0xa7580000);
731 /* ic %r5,<d(pkt_type_offset)>(%r2) */
732 EMIT4_DISP(0x43502000, PKT_TYPE_OFFSET());
733 /* srl %r5,5 */
734 EMIT4_DISP(0x88500000, 5);
735 break;
736 case BPF_ANC | SKF_AD_CPU: /* A = smp_processor_id() */
737 #ifdef CONFIG_SMP
738 /* l %r5,<d(cpu_nr)> */
739 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
740 #else
741 /* lhi %r5,0 */
742 EMIT4(0xa7580000);
743 #endif
744 break;
745 default: /* too complex, give up */
746 goto out;
747 }
748 addrs[i] = jit->prg - jit->start;
749 return 0;
750 out:
751 return -1;
752 }
753
754 void bpf_jit_compile(struct bpf_prog *fp)
755 {
756 struct bpf_binary_header *header = NULL;
757 unsigned long size, prg_len, lit_len;
758 struct bpf_jit jit, cjit;
759 unsigned int *addrs;
760 int pass, i;
761
762 if (!bpf_jit_enable)
763 return;
764 addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
765 if (addrs == NULL)
766 return;
767 memset(&jit, 0, sizeof(cjit));
768 memset(&cjit, 0, sizeof(cjit));
769
770 for (pass = 0; pass < 10; pass++) {
771 jit.prg = jit.start;
772 jit.lit = jit.mid;
773
774 bpf_jit_prologue(&jit);
775 bpf_jit_noleaks(&jit, fp->insns);
776 for (i = 0; i < fp->len; i++) {
777 if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
778 i == fp->len - 1))
779 goto out;
780 }
781 bpf_jit_epilogue(&jit);
782 if (jit.start) {
783 WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
784 if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
785 break;
786 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
787 prg_len = jit.prg - jit.start;
788 lit_len = jit.lit - jit.mid;
789 size = prg_len + lit_len;
790 if (size >= BPF_SIZE_MAX)
791 goto out;
792 header = bpf_jit_binary_alloc(size, &jit.start,
793 2, bpf_jit_fill_hole);
794 if (!header)
795 goto out;
796 jit.prg = jit.mid = jit.start + prg_len;
797 jit.lit = jit.end = jit.start + prg_len + lit_len;
798 jit.base_ip += (unsigned long) jit.start;
799 jit.exit_ip += (unsigned long) jit.start;
800 jit.ret0_ip += (unsigned long) jit.start;
801 }
802 cjit = jit;
803 }
804 if (bpf_jit_enable > 1) {
805 bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
806 if (jit.start)
807 print_fn_code(jit.start, jit.mid - jit.start);
808 }
809 if (jit.start) {
810 set_memory_ro((unsigned long)header, header->pages);
811 fp->bpf_func = (void *) jit.start;
812 fp->jited = true;
813 }
814 out:
815 kfree(addrs);
816 }
817
818 void bpf_jit_free(struct bpf_prog *fp)
819 {
820 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
821 struct bpf_binary_header *header = (void *)addr;
822
823 if (!fp->jited)
824 goto free_filter;
825
826 set_memory_rw(addr, header->pages);
827 bpf_jit_binary_free(header);
828
829 free_filter:
830 bpf_prog_unlock_free(fp);
831 }
Linux kernel - Deliverables
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