projects / deliverable / linux.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
s390/bpf,jit: improve code generation
[deliverable/linux.git] / arch / s390 / net / bpf_jit_comp.c
CommitLineData
c10302ef
MS		 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/filter.h>
11#include <asm/cacheflush.h>
12#include <asm/processor.h>
68d9884d 13#include <asm/facility.h>
c10302ef
MS		 14
15/*
16 * Conventions:
17 * %r2 = skb pointer
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
23 * %r10 = skb->data
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
28 */
29int bpf_jit_enable __read_mostly;
30
31/*
32 * assembly code in arch/x86/net/bpf_jit.S
33 */
34extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
35extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
36
37struct bpf_jit {
38 unsigned int seen;
39 u8 *start;
40 u8 *prg;
41 u8 *mid;
42 u8 *lit;
43 u8 *end;
44 u8 *base_ip;
45 u8 *ret0_ip;
46 u8 *exit_ip;
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;
54};
55
56#define BPF_SIZE_MAX 4096 /* Max size for program */
57
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 */
70
71#define EMIT2(op) \
72({ \
73 if (jit->prg + 2 <= jit->mid) \
74 *(u16 *) jit->prg = op; \
75 jit->prg += 2; \
76})
77
78#define EMIT4(op) \
79({ \
80 if (jit->prg + 4 <= jit->mid) \
81 *(u32 *) jit->prg = op; \
82 jit->prg += 4; \
83})
84
85#define EMIT4_DISP(op, disp) \
86({ \
87 unsigned int __disp = (disp) & 0xfff; \
88 EMIT4(op | __disp); \
89})
90
91#define EMIT4_IMM(op, imm) \
92({ \
93 unsigned int __imm = (imm) & 0xffff; \
94 EMIT4(op | __imm); \
95})
96
97#define EMIT4_PCREL(op, pcrel) \
98({ \
99 long __pcrel = ((pcrel) >> 1) & 0xffff; \
100 EMIT4(op | __pcrel); \
101})
102
103#define EMIT6(op1, op2) \
104({ \
105 if (jit->prg + 6 <= jit->mid) { \
106 *(u32 *) jit->prg = op1; \
107 *(u16 *) (jit->prg + 4) = op2; \
108 } \
109 jit->prg += 6; \
110})
111
112#define EMIT6_DISP(op1, op2, disp) \
113({ \
114 unsigned int __disp = (disp) & 0xfff; \
115 EMIT6(op1 | __disp, op2); \
116})
117
68d9884d
HC		 118#define EMIT6_IMM(op, imm) \
119({ \
120 unsigned int __imm = (imm); \
121 EMIT6(op | (__imm >> 16), __imm & 0xffff); \
122})
123
c10302ef
MS		 124#define EMIT_CONST(val) \
125({ \
126 unsigned int ret; \
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; \
131 jit->lit += 4; \
132 ret; \
133})
134
135#define EMIT_FN_CONST(bit, fn) \
136({ \
137 unsigned int ret; \
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; \
143 jit->lit += 8; \
144 } \
145 ret; \
146})
147
148static void bpf_jit_prologue(struct bpf_jit *jit)
149{
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);
154 /* lgr %r14,%r15 */
155 EMIT4(0xb90400ef);
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);
169
170 /* Setup literal pool */
171 if (jit->seen & SEEN_LITERAL) {
172 /* basr %r13,0 */
173 EMIT2(0x0dd0);
174 jit->base_ip = jit->prg;
175 }
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);
183
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));
193 }
194}
195
196static void bpf_jit_epilogue(struct bpf_jit *jit)
197{
198 /* Return 0 */
199 if (jit->seen & SEEN_RET0) {
200 jit->ret0_ip = jit->prg;
201 /* lghi %r2,0 */
202 EMIT4(0xa7290000);
203 }
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);
219 /* br %r14 */
220 EMIT2(0x07fe);
221}
222
223/*
224 * make sure we dont leak kernel information to user
225 */
226static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
227{
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)
234 /* lhi %r12,0 */
235 EMIT4(0xa7c80000);
236 /* Clear A if the first register does not set it. */
237 switch (filter[0].code) {
238 case BPF_S_LD_W_ABS:
239 case BPF_S_LD_H_ABS:
240 case BPF_S_LD_B_ABS:
241 case BPF_S_LD_W_LEN:
242 case BPF_S_LD_W_IND:
243 case BPF_S_LD_H_IND:
244 case BPF_S_LD_B_IND:
245 case BPF_S_LDX_B_MSH:
246 case BPF_S_LD_IMM:
247 case BPF_S_LD_MEM:
248 case BPF_S_MISC_TXA:
249 case BPF_S_ANC_PROTOCOL:
250 case BPF_S_ANC_PKTTYPE:
251 case BPF_S_ANC_IFINDEX:
252 case BPF_S_ANC_MARK:
253 case BPF_S_ANC_QUEUE:
254 case BPF_S_ANC_HATYPE:
255 case BPF_S_ANC_RXHASH:
256 case BPF_S_ANC_CPU:
257 case BPF_S_RET_K:
258 /* first instruction sets A register */
259 break;
260 default: /* A = 0 */
261 /* lhi %r5,0 */
262 EMIT4(0xa7580000);
263 }
264}
265
266static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
267 unsigned int *addrs, int i, int last)
268{
269 unsigned int K;
270 int offset;
271 unsigned int mask;
272
273 K = filter->k;
274 switch (filter->code) {
275 case BPF_S_ALU_ADD_X: /* A += X */
276 jit->seen |= SEEN_XREG;
277 /* ar %r5,%r12 */
278 EMIT2(0x1a5c);
279 break;
280 case BPF_S_ALU_ADD_K: /* A += K */
281 if (!K)
282 break;
283 if (K <= 16383)
284 /* ahi %r5,<K> */
285 EMIT4_IMM(0xa75a0000, K);
68d9884d
HC		 286 else if (test_facility(21))
287 /* alfi %r5,<K> */
288 EMIT6_IMM(0xc25b0000, K);
c10302ef
MS		 289 else
290 /* a %r5,<d(K)>(%r13) */
291 EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
292 break;
293 case BPF_S_ALU_SUB_X: /* A -= X */
294 jit->seen |= SEEN_XREG;
295 /* sr %r5,%r12 */
296 EMIT2(0x1b5c);
297 break;
298 case BPF_S_ALU_SUB_K: /* A -= K */
299 if (!K)
300 break;
301 if (K <= 16384)
302 /* ahi %r5,-K */
303 EMIT4_IMM(0xa75a0000, -K);
68d9884d
HC		 304 else if (test_facility(21))
305 /* alfi %r5,-K */
306 EMIT6_IMM(0xc25b0000, -K);
c10302ef
MS		 307 else
308 /* s %r5,<d(K)>(%r13) */
309 EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
310 break;
311 case BPF_S_ALU_MUL_X: /* A *= X */
312 jit->seen |= SEEN_XREG;
313 /* msr %r5,%r12 */
314 EMIT4(0xb252005c);
315 break;
316 case BPF_S_ALU_MUL_K: /* A *= K */
317 if (K <= 16383)
318 /* mhi %r5,K */
319 EMIT4_IMM(0xa75c0000, K);
68d9884d
HC		 320 else if (test_facility(34))
321 /* msfi %r5,<K> */
322 EMIT6_IMM(0xc2510000, K);
c10302ef
MS		 323 else
324 /* ms %r5,<d(K)>(%r13) */
325 EMIT4_DISP(0x7150d000, EMIT_CONST(K));
326 break;
327 case BPF_S_ALU_DIV_X: /* A /= X */
328 jit->seen |= SEEN_XREG | SEEN_RET0;
329 /* ltr %r12,%r12 */
330 EMIT2(0x12cc);
331 /* jz <ret0> */
332 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
333 /* lhi %r4,0 */
334 EMIT4(0xa7480000);
335 /* dr %r4,%r12 */
336 EMIT2(0x1d4c);
337 break;
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));
341 /* lr %r5,%r4 */
342 EMIT2(0x1854);
343 break;
344 case BPF_S_ALU_AND_X: /* A &= X */
345 jit->seen |= SEEN_XREG;
346 /* nr %r5,%r12 */
347 EMIT2(0x145c);
348 break;
349 case BPF_S_ALU_AND_K: /* A &= K */
68d9884d
HC		 350 if (test_facility(21))
351 /* nilf %r5,<K> */
352 EMIT6_IMM(0xc05b0000, K);
353 else
354 /* n %r5,<d(K)>(%r13) */
355 EMIT4_DISP(0x5450d000, EMIT_CONST(K));
c10302ef
MS		 356 break;
357 case BPF_S_ALU_OR_X: /* A |= X */
358 jit->seen |= SEEN_XREG;
359 /* or %r5,%r12 */
360 EMIT2(0x165c);
361 break;
362 case BPF_S_ALU_OR_K: /* A |= K */
68d9884d
HC		 363 if (test_facility(21))
364 /* oilf %r5,<K> */
365 EMIT6_IMM(0xc05d0000, K);
366 else
367 /* o %r5,<d(K)>(%r13) */
368 EMIT4_DISP(0x5650d000, EMIT_CONST(K));
c10302ef
MS		 369 break;
370 case BPF_S_ALU_LSH_X: /* A <<= X; */
371 jit->seen |= SEEN_XREG;
372 /* sll %r5,0(%r12) */
373 EMIT4(0x8950c000);
374 break;
375 case BPF_S_ALU_LSH_K: /* A <<= K */
376 if (K == 0)
377 break;
378 /* sll %r5,K */
379 EMIT4_DISP(0x89500000, K);
380 break;
381 case BPF_S_ALU_RSH_X: /* A >>= X; */
382 jit->seen |= SEEN_XREG;
383 /* srl %r5,0(%r12) */
384 EMIT4(0x8850c000);
385 break;
386 case BPF_S_ALU_RSH_K: /* A >>= K; */
387 if (K == 0)
388 break;
389 /* srl %r5,K */
390 EMIT4_DISP(0x88500000, K);
391 break;
392 case BPF_S_ALU_NEG: /* A = -A */
393 /* lnr %r5,%r5 */
394 EMIT2(0x1155);
395 break;
396 case BPF_S_JMP_JA: /* ip += K */
397 offset = addrs[i + K] + jit->start - jit->prg;
398 EMIT4_PCREL(0xa7f40000, offset);
399 break;
400 case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
401 mask = 0x200000; /* jh */
402 goto kbranch;
403 case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
404 mask = 0xa00000; /* jhe */
405 goto kbranch;
406 case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
407 mask = 0x800000; /* je */
408kbranch: /* Emit compare if the branch targets are different */
409 if (filter->jt != filter->jf) {
410 if (K <= 16383)
411 /* chi %r5,<K> */
412 EMIT4_IMM(0xa75e0000, K);
68d9884d
HC		 413 else if (test_facility(21))
414 /* clfi %r5,<K> */
415 EMIT6_IMM(0xc25f0000, K);
c10302ef
MS		 416 else
417 /* c %r5,<d(K)>(%r13) */
418 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
419 }
420branch: if (filter->jt == filter->jf) {
421 if (filter->jt == 0)
422 break;
423 /* j <jt> */
424 offset = addrs[i + filter->jt] + jit->start - jit->prg;
425 EMIT4_PCREL(0xa7f40000, offset);
426 break;
427 }
428 if (filter->jt != 0) {
429 /* brc <mask>,<jt> */
430 offset = addrs[i + filter->jt] + jit->start - jit->prg;
431 EMIT4_PCREL(0xa7040000 | mask, offset);
432 }
433 if (filter->jf != 0) {
434 /* brc <mask^15>,<jf> */
435 offset = addrs[i + filter->jf] + jit->start - jit->prg;
436 EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
437 }
438 break;
439 case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
440 mask = 0x700000; /* jnz */
441 /* Emit test if the branch targets are different */
442 if (filter->jt != filter->jf) {
443 if (K > 65535) {
444 /* lr %r4,%r5 */
445 EMIT2(0x1845);
446 /* n %r4,<d(K)>(%r13) */
447 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
448 } else
449 /* tmll %r5,K */
450 EMIT4_IMM(0xa7510000, K);
451 }
452 goto branch;
453 case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
454 mask = 0x200000; /* jh */
455 goto xbranch;
456 case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
457 mask = 0xa00000; /* jhe */
458 goto xbranch;
459 case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
460 mask = 0x800000; /* je */
461xbranch: /* Emit compare if the branch targets are different */
462 if (filter->jt != filter->jf) {
463 jit->seen |= SEEN_XREG;
464 /* cr %r5,%r12 */
465 EMIT2(0x195c);
466 }
467 goto branch;
468 case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
469 mask = 0x700000; /* jnz */
470 /* Emit test if the branch targets are different */
471 if (filter->jt != filter->jf) {
472 jit->seen |= SEEN_XREG;
473 /* lr %r4,%r5 */
474 EMIT2(0x1845);
475 /* nr %r4,%r12 */
476 EMIT2(0x144c);
477 }
478 goto branch;
479 case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
480 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
481 offset = jit->off_load_word;
482 goto load_abs;
483 case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
484 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
485 offset = jit->off_load_half;
486 goto load_abs;
487 case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
488 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
489 offset = jit->off_load_byte;
490load_abs: if ((int) K < 0)
491 goto out;
492call_fn: /* lg %r1,<d(function)>(%r13) */
493 EMIT6_DISP(0xe310d000, 0x0004, offset);
494 /* l %r3,<d(K)>(%r13) */
495 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
496 /* basr %r8,%r1 */
497 EMIT2(0x0d81);
498 /* jnz <ret0> */
499 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
500 break;
501 case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
502 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
503 offset = jit->off_load_iword;
504 goto call_fn;
505 case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
506 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
507 offset = jit->off_load_ihalf;
508 goto call_fn;
509 case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
510 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
511 offset = jit->off_load_ibyte;
512 goto call_fn;
513 case BPF_S_LDX_B_MSH:
514 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
515 jit->seen |= SEEN_RET0;
516 if ((int) K < 0) {
517 /* j <ret0> */
518 EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
519 break;
520 }
521 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
522 offset = jit->off_load_bmsh;
523 goto call_fn;
524 case BPF_S_LD_W_LEN: /* A = skb->len; */
525 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
526 /* l %r5,<d(len)>(%r2) */
527 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
528 break;
529 case BPF_S_LDX_W_LEN: /* X = skb->len; */
530 jit->seen |= SEEN_XREG;
531 /* l %r12,<d(len)>(%r2) */
532 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
533 break;
534 case BPF_S_LD_IMM: /* A = K */
535 if (K <= 16383)
536 /* lhi %r5,K */
537 EMIT4_IMM(0xa7580000, K);
68d9884d
HC		 538 else if (test_facility(21))
539 /* llilf %r5,<K> */
540 EMIT6_IMM(0xc05f0000, K);
c10302ef
MS		 541 else
542 /* l %r5,<d(K)>(%r13) */
543 EMIT4_DISP(0x5850d000, EMIT_CONST(K));
544 break;
545 case BPF_S_LDX_IMM: /* X = K */
546 jit->seen |= SEEN_XREG;
547 if (K <= 16383)
548 /* lhi %r12,<K> */
549 EMIT4_IMM(0xa7c80000, K);
68d9884d
HC		 550 else if (test_facility(21))
551 /* llilf %r12,<K> */
552 EMIT6_IMM(0xc0cf0000, K);
c10302ef
MS		 553 else
554 /* l %r12,<d(K)>(%r13) */
555 EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
556 break;
557 case BPF_S_LD_MEM: /* A = mem[K] */
558 jit->seen |= SEEN_MEM;
559 /* l %r5,<K>(%r15) */
560 EMIT4_DISP(0x5850f000,
561 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
562 break;
563 case BPF_S_LDX_MEM: /* X = mem[K] */
564 jit->seen |= SEEN_XREG | SEEN_MEM;
565 /* l %r12,<K>(%r15) */
566 EMIT4_DISP(0x58c0f000,
567 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
568 break;
569 case BPF_S_MISC_TAX: /* X = A */
570 jit->seen |= SEEN_XREG;
571 /* lr %r12,%r5 */
572 EMIT2(0x18c5);
573 break;
574 case BPF_S_MISC_TXA: /* A = X */
575 jit->seen |= SEEN_XREG;
576 /* lr %r5,%r12 */
577 EMIT2(0x185c);
578 break;
579 case BPF_S_RET_K:
580 if (K == 0) {
581 jit->seen |= SEEN_RET0;
582 if (last)
583 break;
584 /* j <ret0> */
585 EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
586 } else {
587 if (K <= 16383)
588 /* lghi %r2,K */
589 EMIT4_IMM(0xa7290000, K);
590 else
591 /* llgf %r2,<K>(%r13) */
592 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
593 /* j <exit> */
594 if (last && !(jit->seen & SEEN_RET0))
595 break;
596 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
597 }
598 break;
599 case BPF_S_RET_A:
600 /* llgfr %r2,%r5 */
601 EMIT4(0xb9160025);
602 /* j <exit> */
603 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
604 break;
605 case BPF_S_ST: /* mem[K] = A */
606 jit->seen |= SEEN_MEM;
607 /* st %r5,<K>(%r15) */
608 EMIT4_DISP(0x5050f000,
609 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
610 break;
611 case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
612 jit->seen |= SEEN_XREG | SEEN_MEM;
613 /* st %r12,<K>(%r15) */
614 EMIT4_DISP(0x50c0f000,
615 (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
616 break;
617 case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
618 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
619 /* lhi %r5,0 */
620 EMIT4(0xa7580000);
621 /* icm %r5,3,<d(protocol)>(%r2) */
622 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
623 break;
624 case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
625 * A = skb->dev->ifindex */
626 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
627 jit->seen |= SEEN_RET0;
628 /* lg %r1,<d(dev)>(%r2) */
629 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
630 /* ltgr %r1,%r1 */
631 EMIT4(0xb9020011);
632 /* jz <ret0> */
633 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
634 /* l %r5,<d(ifindex)>(%r1) */
635 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
636 break;
637 case BPF_S_ANC_MARK: /* A = skb->mark */
638 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
639 /* l %r5,<d(mark)>(%r2) */
640 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
641 break;
642 case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
643 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
644 /* lhi %r5,0 */
645 EMIT4(0xa7580000);
646 /* icm %r5,3,<d(queue_mapping)>(%r2) */
647 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
648 break;
649 case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0;
650 * A = skb->dev->type */
651 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
652 jit->seen |= SEEN_RET0;
653 /* lg %r1,<d(dev)>(%r2) */
654 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
655 /* ltgr %r1,%r1 */
656 EMIT4(0xb9020011);
657 /* jz <ret0> */
658 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
659 /* lhi %r5,0 */
660 EMIT4(0xa7580000);
661 /* icm %r5,3,<d(type)>(%r1) */
662 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
663 break;
664 case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
665 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
666 /* l %r5,<d(rxhash)>(%r2) */
667 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
668 break;
669 case BPF_S_ANC_CPU: /* A = smp_processor_id() */
670#ifdef CONFIG_SMP
671 /* l %r5,<d(cpu_nr)> */
672 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
673#else
674 /* lhi %r5,0 */
675 EMIT4(0xa7580000);
676#endif
677 break;
678 default: /* too complex, give up */
679 goto out;
680 }
681 addrs[i] = jit->prg - jit->start;
682 return 0;
683out:
684 return -1;
685}
686
687void bpf_jit_compile(struct sk_filter *fp)
688{
689 unsigned long size, prg_len, lit_len;
690 struct bpf_jit jit, cjit;
691 unsigned int *addrs;
692 int pass, i;
693
694 if (!bpf_jit_enable)
695 return;
696 addrs = kmalloc(fp->len * sizeof(*addrs), GFP_KERNEL);
697 if (addrs == NULL)
698 return;
699 memset(addrs, 0, fp->len * sizeof(*addrs));
700 memset(&jit, 0, sizeof(cjit));
701 memset(&cjit, 0, sizeof(cjit));
702
703 for (pass = 0; pass < 10; pass++) {
704 jit.prg = jit.start;
705 jit.lit = jit.mid;
706
707 bpf_jit_prologue(&jit);
708 bpf_jit_noleaks(&jit, fp->insns);
709 for (i = 0; i < fp->len; i++) {
710 if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
711 i == fp->len - 1))
712 goto out;
713 }
714 bpf_jit_epilogue(&jit);
715 if (jit.start) {
716 WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
717 if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
718 break;
719 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
720 prg_len = jit.prg - jit.start;
721 lit_len = jit.lit - jit.mid;
722 size = max_t(unsigned long, prg_len + lit_len,
723 sizeof(struct work_struct));
724 if (size >= BPF_SIZE_MAX)
725 goto out;
726 jit.start = module_alloc(size);
727 if (!jit.start)
728 goto out;
729 jit.prg = jit.mid = jit.start + prg_len;
730 jit.lit = jit.end = jit.start + prg_len + lit_len;
731 jit.base_ip += (unsigned long) jit.start;
732 jit.exit_ip += (unsigned long) jit.start;
733 jit.ret0_ip += (unsigned long) jit.start;
734 }
735 cjit = jit;
736 }
737 if (bpf_jit_enable > 1) {
738 pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
739 fp->len, jit.end - jit.start, pass, jit.start);
740 if (jit.start) {
741 printk(KERN_ERR "JIT code:\n");
742 print_fn_code(jit.start, jit.mid - jit.start);
743 print_hex_dump(KERN_ERR, "JIT literals:\n",
744 DUMP_PREFIX_ADDRESS, 16, 1,
745 jit.mid, jit.end - jit.mid, false);
746 }
747 }
748 if (jit.start)
749 fp->bpf_func = (void *) jit.start;
750out:
751 kfree(addrs);
752}
753
754static void jit_free_defer(struct work_struct *arg)
755{
756 module_free(NULL, arg);
757}
758
759/* run from softirq, we must use a work_struct to call
760 * module_free() from process context
761 */
762void bpf_jit_free(struct sk_filter *fp)
763{
764 struct work_struct *work;
765
766 if (fp->bpf_func == sk_run_filter)
767 return;
768 work = (struct work_struct *)fp->bpf_func;
769 INIT_WORK(work, jit_free_defer);
770 schedule_work(work);
771}
Linux kernel - Deliverables
This page took 0.107831 seconds and 5 git commands to generate.