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Merge tag 'iommu-updates-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro...
[mirror_ubuntu-zesty-kernel.git] / arch / s390 / net / bpf_jit_comp.c
1 /*
2 * BPF Jit compiler for s390.
3 *
4 * Minimum build requirements:
5 *
6 * - HAVE_MARCH_Z196_FEATURES: laal, laalg
7 * - HAVE_MARCH_Z10_FEATURES: msfi, cgrj, clgrj
8 * - HAVE_MARCH_Z9_109_FEATURES: alfi, llilf, clfi, oilf, nilf
9 * - PACK_STACK
10 * - 64BIT
11 *
12 * Copyright IBM Corp. 2012,2015
13 *
14 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
15 * Michael Holzheu <holzheu@linux.vnet.ibm.com>
16 */
17
18 #define KMSG_COMPONENT "bpf_jit"
19 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
20
21 #include <linux/netdevice.h>
22 #include <linux/filter.h>
23 #include <linux/init.h>
24 #include <linux/bpf.h>
25 #include <asm/cacheflush.h>
26 #include <asm/dis.h>
27 #include "bpf_jit.h"
28
29 int bpf_jit_enable __read_mostly;
30
31 struct bpf_jit {
32 u32 seen; /* Flags to remember seen eBPF instructions */
33 u32 seen_reg[16]; /* Array to remember which registers are used */
34 u32 *addrs; /* Array with relative instruction addresses */
35 u8 *prg_buf; /* Start of program */
36 int size; /* Size of program and literal pool */
37 int size_prg; /* Size of program */
38 int prg; /* Current position in program */
39 int lit_start; /* Start of literal pool */
40 int lit; /* Current position in literal pool */
41 int base_ip; /* Base address for literal pool */
42 int ret0_ip; /* Address of return 0 */
43 int exit_ip; /* Address of exit */
44 int tail_call_start; /* Tail call start offset */
45 int labels[1]; /* Labels for local jumps */
46 };
47
48 #define BPF_SIZE_MAX 0x7ffff /* Max size for program (20 bit signed displ) */
49
50 #define SEEN_SKB 1 /* skb access */
51 #define SEEN_MEM 2 /* use mem[] for temporary storage */
52 #define SEEN_RET0 4 /* ret0_ip points to a valid return 0 */
53 #define SEEN_LITERAL 8 /* code uses literals */
54 #define SEEN_FUNC 16 /* calls C functions */
55 #define SEEN_TAIL_CALL 32 /* code uses tail calls */
56 #define SEEN_SKB_CHANGE 64 /* code changes skb data */
57 #define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB)
58
59 /*
60 * s390 registers
61 */
62 #define REG_W0 (__MAX_BPF_REG+0) /* Work register 1 (even) */
63 #define REG_W1 (__MAX_BPF_REG+1) /* Work register 2 (odd) */
64 #define REG_SKB_DATA (__MAX_BPF_REG+2) /* SKB data register */
65 #define REG_L (__MAX_BPF_REG+3) /* Literal pool register */
66 #define REG_15 (__MAX_BPF_REG+4) /* Register 15 */
67 #define REG_0 REG_W0 /* Register 0 */
68 #define REG_1 REG_W1 /* Register 1 */
69 #define REG_2 BPF_REG_1 /* Register 2 */
70 #define REG_14 BPF_REG_0 /* Register 14 */
71
72 /*
73 * Mapping of BPF registers to s390 registers
74 */
75 static const int reg2hex[] = {
76 /* Return code */
77 [BPF_REG_0] = 14,
78 /* Function parameters */
79 [BPF_REG_1] = 2,
80 [BPF_REG_2] = 3,
81 [BPF_REG_3] = 4,
82 [BPF_REG_4] = 5,
83 [BPF_REG_5] = 6,
84 /* Call saved registers */
85 [BPF_REG_6] = 7,
86 [BPF_REG_7] = 8,
87 [BPF_REG_8] = 9,
88 [BPF_REG_9] = 10,
89 /* BPF stack pointer */
90 [BPF_REG_FP] = 13,
91 /* SKB data pointer */
92 [REG_SKB_DATA] = 12,
93 /* Work registers for s390x backend */
94 [REG_W0] = 0,
95 [REG_W1] = 1,
96 [REG_L] = 11,
97 [REG_15] = 15,
98 };
99
100 static inline u32 reg(u32 dst_reg, u32 src_reg)
101 {
102 return reg2hex[dst_reg] << 4 | reg2hex[src_reg];
103 }
104
105 static inline u32 reg_high(u32 reg)
106 {
107 return reg2hex[reg] << 4;
108 }
109
110 static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
111 {
112 u32 r1 = reg2hex[b1];
113
114 if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15)
115 jit->seen_reg[r1] = 1;
116 }
117
118 #define REG_SET_SEEN(b1) \
119 ({ \
120 reg_set_seen(jit, b1); \
121 })
122
123 #define REG_SEEN(b1) jit->seen_reg[reg2hex[(b1)]]
124
125 /*
126 * EMIT macros for code generation
127 */
128
129 #define _EMIT2(op) \
130 ({ \
131 if (jit->prg_buf) \
132 *(u16 *) (jit->prg_buf + jit->prg) = op; \
133 jit->prg += 2; \
134 })
135
136 #define EMIT2(op, b1, b2) \
137 ({ \
138 _EMIT2(op | reg(b1, b2)); \
139 REG_SET_SEEN(b1); \
140 REG_SET_SEEN(b2); \
141 })
142
143 #define _EMIT4(op) \
144 ({ \
145 if (jit->prg_buf) \
146 *(u32 *) (jit->prg_buf + jit->prg) = op; \
147 jit->prg += 4; \
148 })
149
150 #define EMIT4(op, b1, b2) \
151 ({ \
152 _EMIT4(op | reg(b1, b2)); \
153 REG_SET_SEEN(b1); \
154 REG_SET_SEEN(b2); \
155 })
156
157 #define EMIT4_RRF(op, b1, b2, b3) \
158 ({ \
159 _EMIT4(op | reg_high(b3) << 8 | reg(b1, b2)); \
160 REG_SET_SEEN(b1); \
161 REG_SET_SEEN(b2); \
162 REG_SET_SEEN(b3); \
163 })
164
165 #define _EMIT4_DISP(op, disp) \
166 ({ \
167 unsigned int __disp = (disp) & 0xfff; \
168 _EMIT4(op | __disp); \
169 })
170
171 #define EMIT4_DISP(op, b1, b2, disp) \
172 ({ \
173 _EMIT4_DISP(op | reg_high(b1) << 16 | \
174 reg_high(b2) << 8, disp); \
175 REG_SET_SEEN(b1); \
176 REG_SET_SEEN(b2); \
177 })
178
179 #define EMIT4_IMM(op, b1, imm) \
180 ({ \
181 unsigned int __imm = (imm) & 0xffff; \
182 _EMIT4(op | reg_high(b1) << 16 | __imm); \
183 REG_SET_SEEN(b1); \
184 })
185
186 #define EMIT4_PCREL(op, pcrel) \
187 ({ \
188 long __pcrel = ((pcrel) >> 1) & 0xffff; \
189 _EMIT4(op | __pcrel); \
190 })
191
192 #define _EMIT6(op1, op2) \
193 ({ \
194 if (jit->prg_buf) { \
195 *(u32 *) (jit->prg_buf + jit->prg) = op1; \
196 *(u16 *) (jit->prg_buf + jit->prg + 4) = op2; \
197 } \
198 jit->prg += 6; \
199 })
200
201 #define _EMIT6_DISP(op1, op2, disp) \
202 ({ \
203 unsigned int __disp = (disp) & 0xfff; \
204 _EMIT6(op1 | __disp, op2); \
205 })
206
207 #define _EMIT6_DISP_LH(op1, op2, disp) \
208 ({ \
209 u32 _disp = (u32) disp; \
210 unsigned int __disp_h = _disp & 0xff000; \
211 unsigned int __disp_l = _disp & 0x00fff; \
212 _EMIT6(op1 | __disp_l, op2 | __disp_h >> 4); \
213 })
214
215 #define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp) \
216 ({ \
217 _EMIT6_DISP_LH(op1 | reg(b1, b2) << 16 | \
218 reg_high(b3) << 8, op2, disp); \
219 REG_SET_SEEN(b1); \
220 REG_SET_SEEN(b2); \
221 REG_SET_SEEN(b3); \
222 })
223
224 #define EMIT6_PCREL_LABEL(op1, op2, b1, b2, label, mask) \
225 ({ \
226 int rel = (jit->labels[label] - jit->prg) >> 1; \
227 _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), \
228 op2 | mask << 12); \
229 REG_SET_SEEN(b1); \
230 REG_SET_SEEN(b2); \
231 })
232
233 #define EMIT6_PCREL_IMM_LABEL(op1, op2, b1, imm, label, mask) \
234 ({ \
235 int rel = (jit->labels[label] - jit->prg) >> 1; \
236 _EMIT6(op1 | (reg_high(b1) | mask) << 16 | \
237 (rel & 0xffff), op2 | (imm & 0xff) << 8); \
238 REG_SET_SEEN(b1); \
239 BUILD_BUG_ON(((unsigned long) imm) > 0xff); \
240 })
241
242 #define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
243 ({ \
244 /* Branch instruction needs 6 bytes */ \
245 int rel = (addrs[i + off + 1] - (addrs[i + 1] - 6)) / 2;\
246 _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), op2 | mask); \
247 REG_SET_SEEN(b1); \
248 REG_SET_SEEN(b2); \
249 })
250
251 #define _EMIT6_IMM(op, imm) \
252 ({ \
253 unsigned int __imm = (imm); \
254 _EMIT6(op | (__imm >> 16), __imm & 0xffff); \
255 })
256
257 #define EMIT6_IMM(op, b1, imm) \
258 ({ \
259 _EMIT6_IMM(op | reg_high(b1) << 16, imm); \
260 REG_SET_SEEN(b1); \
261 })
262
263 #define EMIT_CONST_U32(val) \
264 ({ \
265 unsigned int ret; \
266 ret = jit->lit - jit->base_ip; \
267 jit->seen |= SEEN_LITERAL; \
268 if (jit->prg_buf) \
269 *(u32 *) (jit->prg_buf + jit->lit) = (u32) val; \
270 jit->lit += 4; \
271 ret; \
272 })
273
274 #define EMIT_CONST_U64(val) \
275 ({ \
276 unsigned int ret; \
277 ret = jit->lit - jit->base_ip; \
278 jit->seen |= SEEN_LITERAL; \
279 if (jit->prg_buf) \
280 *(u64 *) (jit->prg_buf + jit->lit) = (u64) val; \
281 jit->lit += 8; \
282 ret; \
283 })
284
285 #define EMIT_ZERO(b1) \
286 ({ \
287 /* llgfr %dst,%dst (zero extend to 64 bit) */ \
288 EMIT4(0xb9160000, b1, b1); \
289 REG_SET_SEEN(b1); \
290 })
291
292 /*
293 * Fill whole space with illegal instructions
294 */
295 static void jit_fill_hole(void *area, unsigned int size)
296 {
297 memset(area, 0, size);
298 }
299
300 /*
301 * Save registers from "rs" (register start) to "re" (register end) on stack
302 */
303 static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
304 {
305 u32 off = STK_OFF_R6 + (rs - 6) * 8;
306
307 if (rs == re)
308 /* stg %rs,off(%r15) */
309 _EMIT6(0xe300f000 | rs << 20 | off, 0x0024);
310 else
311 /* stmg %rs,%re,off(%r15) */
312 _EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0024, off);
313 }
314
315 /*
316 * Restore registers from "rs" (register start) to "re" (register end) on stack
317 */
318 static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re)
319 {
320 u32 off = STK_OFF_R6 + (rs - 6) * 8;
321
322 if (jit->seen & SEEN_STACK)
323 off += STK_OFF;
324
325 if (rs == re)
326 /* lg %rs,off(%r15) */
327 _EMIT6(0xe300f000 | rs << 20 | off, 0x0004);
328 else
329 /* lmg %rs,%re,off(%r15) */
330 _EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0004, off);
331 }
332
333 /*
334 * Return first seen register (from start)
335 */
336 static int get_start(struct bpf_jit *jit, int start)
337 {
338 int i;
339
340 for (i = start; i <= 15; i++) {
341 if (jit->seen_reg[i])
342 return i;
343 }
344 return 0;
345 }
346
347 /*
348 * Return last seen register (from start) (gap >= 2)
349 */
350 static int get_end(struct bpf_jit *jit, int start)
351 {
352 int i;
353
354 for (i = start; i < 15; i++) {
355 if (!jit->seen_reg[i] && !jit->seen_reg[i + 1])
356 return i - 1;
357 }
358 return jit->seen_reg[15] ? 15 : 14;
359 }
360
361 #define REGS_SAVE 1
362 #define REGS_RESTORE 0
363 /*
364 * Save and restore clobbered registers (6-15) on stack.
365 * We save/restore registers in chunks with gap >= 2 registers.
366 */
367 static void save_restore_regs(struct bpf_jit *jit, int op)
368 {
369
370 int re = 6, rs;
371
372 do {
373 rs = get_start(jit, re);
374 if (!rs)
375 break;
376 re = get_end(jit, rs + 1);
377 if (op == REGS_SAVE)
378 save_regs(jit, rs, re);
379 else
380 restore_regs(jit, rs, re);
381 re++;
382 } while (re <= 15);
383 }
384
385 /*
386 * For SKB access %b1 contains the SKB pointer. For "bpf_jit.S"
387 * we store the SKB header length on the stack and the SKB data
388 * pointer in REG_SKB_DATA.
389 */
390 static void emit_load_skb_data_hlen(struct bpf_jit *jit)
391 {
392 /* Header length: llgf %w1,<len>(%b1) */
393 EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_1,
394 offsetof(struct sk_buff, len));
395 /* s %w1,<data_len>(%b1) */
396 EMIT4_DISP(0x5b000000, REG_W1, BPF_REG_1,
397 offsetof(struct sk_buff, data_len));
398 /* stg %w1,ST_OFF_HLEN(%r0,%r15) */
399 EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15, STK_OFF_HLEN);
400 /* lg %skb_data,data_off(%b1) */
401 EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0,
402 BPF_REG_1, offsetof(struct sk_buff, data));
403 }
404
405 /*
406 * Emit function prologue
407 *
408 * Save registers and create stack frame if necessary.
409 * See stack frame layout desription in "bpf_jit.h"!
410 */
411 static void bpf_jit_prologue(struct bpf_jit *jit)
412 {
413 if (jit->seen & SEEN_TAIL_CALL) {
414 /* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
415 _EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
416 } else {
417 /* j tail_call_start: NOP if no tail calls are used */
418 EMIT4_PCREL(0xa7f40000, 6);
419 _EMIT2(0);
420 }
421 /* Tail calls have to skip above initialization */
422 jit->tail_call_start = jit->prg;
423 /* Save registers */
424 save_restore_regs(jit, REGS_SAVE);
425 /* Setup literal pool */
426 if (jit->seen & SEEN_LITERAL) {
427 /* basr %r13,0 */
428 EMIT2(0x0d00, REG_L, REG_0);
429 jit->base_ip = jit->prg;
430 }
431 /* Setup stack and backchain */
432 if (jit->seen & SEEN_STACK) {
433 if (jit->seen & SEEN_FUNC)
434 /* lgr %w1,%r15 (backchain) */
435 EMIT4(0xb9040000, REG_W1, REG_15);
436 /* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
437 EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
438 /* aghi %r15,-STK_OFF */
439 EMIT4_IMM(0xa70b0000, REG_15, -STK_OFF);
440 if (jit->seen & SEEN_FUNC)
441 /* stg %w1,152(%r15) (backchain) */
442 EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
443 REG_15, 152);
444 }
445 if (jit->seen & SEEN_SKB)
446 emit_load_skb_data_hlen(jit);
447 if (jit->seen & SEEN_SKB_CHANGE)
448 /* stg %b1,ST_OFF_SKBP(%r0,%r15) */
449 EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15,
450 STK_OFF_SKBP);
451 }
452
453 /*
454 * Function epilogue
455 */
456 static void bpf_jit_epilogue(struct bpf_jit *jit)
457 {
458 /* Return 0 */
459 if (jit->seen & SEEN_RET0) {
460 jit->ret0_ip = jit->prg;
461 /* lghi %b0,0 */
462 EMIT4_IMM(0xa7090000, BPF_REG_0, 0);
463 }
464 jit->exit_ip = jit->prg;
465 /* Load exit code: lgr %r2,%b0 */
466 EMIT4(0xb9040000, REG_2, BPF_REG_0);
467 /* Restore registers */
468 save_restore_regs(jit, REGS_RESTORE);
469 /* br %r14 */
470 _EMIT2(0x07fe);
471 }
472
473 /*
474 * Compile one eBPF instruction into s390x code
475 *
476 * NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
477 * stack space for the large switch statement.
478 */
479 static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
480 {
481 struct bpf_insn *insn = &fp->insnsi[i];
482 int jmp_off, last, insn_count = 1;
483 unsigned int func_addr, mask;
484 u32 dst_reg = insn->dst_reg;
485 u32 src_reg = insn->src_reg;
486 u32 *addrs = jit->addrs;
487 s32 imm = insn->imm;
488 s16 off = insn->off;
489
490 switch (insn->code) {
491 /*
492 * BPF_MOV
493 */
494 case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
495 /* llgfr %dst,%src */
496 EMIT4(0xb9160000, dst_reg, src_reg);
497 break;
498 case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
499 /* lgr %dst,%src */
500 EMIT4(0xb9040000, dst_reg, src_reg);
501 break;
502 case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
503 /* llilf %dst,imm */
504 EMIT6_IMM(0xc00f0000, dst_reg, imm);
505 break;
506 case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
507 /* lgfi %dst,imm */
508 EMIT6_IMM(0xc0010000, dst_reg, imm);
509 break;
510 /*
511 * BPF_LD 64
512 */
513 case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
514 {
515 /* 16 byte instruction that uses two 'struct bpf_insn' */
516 u64 imm64;
517
518 imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;
519 /* lg %dst,<d(imm)>(%l) */
520 EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, REG_0, REG_L,
521 EMIT_CONST_U64(imm64));
522 insn_count = 2;
523 break;
524 }
525 /*
526 * BPF_ADD
527 */
528 case BPF_ALU | BPF_ADD | BPF_X: /* dst = (u32) dst + (u32) src */
529 /* ar %dst,%src */
530 EMIT2(0x1a00, dst_reg, src_reg);
531 EMIT_ZERO(dst_reg);
532 break;
533 case BPF_ALU64 | BPF_ADD | BPF_X: /* dst = dst + src */
534 /* agr %dst,%src */
535 EMIT4(0xb9080000, dst_reg, src_reg);
536 break;
537 case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
538 if (!imm)
539 break;
540 /* alfi %dst,imm */
541 EMIT6_IMM(0xc20b0000, dst_reg, imm);
542 EMIT_ZERO(dst_reg);
543 break;
544 case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
545 if (!imm)
546 break;
547 /* agfi %dst,imm */
548 EMIT6_IMM(0xc2080000, dst_reg, imm);
549 break;
550 /*
551 * BPF_SUB
552 */
553 case BPF_ALU | BPF_SUB | BPF_X: /* dst = (u32) dst - (u32) src */
554 /* sr %dst,%src */
555 EMIT2(0x1b00, dst_reg, src_reg);
556 EMIT_ZERO(dst_reg);
557 break;
558 case BPF_ALU64 | BPF_SUB | BPF_X: /* dst = dst - src */
559 /* sgr %dst,%src */
560 EMIT4(0xb9090000, dst_reg, src_reg);
561 break;
562 case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
563 if (!imm)
564 break;
565 /* alfi %dst,-imm */
566 EMIT6_IMM(0xc20b0000, dst_reg, -imm);
567 EMIT_ZERO(dst_reg);
568 break;
569 case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
570 if (!imm)
571 break;
572 /* agfi %dst,-imm */
573 EMIT6_IMM(0xc2080000, dst_reg, -imm);
574 break;
575 /*
576 * BPF_MUL
577 */
578 case BPF_ALU | BPF_MUL | BPF_X: /* dst = (u32) dst * (u32) src */
579 /* msr %dst,%src */
580 EMIT4(0xb2520000, dst_reg, src_reg);
581 EMIT_ZERO(dst_reg);
582 break;
583 case BPF_ALU64 | BPF_MUL | BPF_X: /* dst = dst * src */
584 /* msgr %dst,%src */
585 EMIT4(0xb90c0000, dst_reg, src_reg);
586 break;
587 case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
588 if (imm == 1)
589 break;
590 /* msfi %r5,imm */
591 EMIT6_IMM(0xc2010000, dst_reg, imm);
592 EMIT_ZERO(dst_reg);
593 break;
594 case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
595 if (imm == 1)
596 break;
597 /* msgfi %dst,imm */
598 EMIT6_IMM(0xc2000000, dst_reg, imm);
599 break;
600 /*
601 * BPF_DIV / BPF_MOD
602 */
603 case BPF_ALU | BPF_DIV | BPF_X: /* dst = (u32) dst / (u32) src */
604 case BPF_ALU | BPF_MOD | BPF_X: /* dst = (u32) dst % (u32) src */
605 {
606 int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
607
608 jit->seen |= SEEN_RET0;
609 /* ltr %src,%src (if src == 0 goto fail) */
610 EMIT2(0x1200, src_reg, src_reg);
611 /* jz <ret0> */
612 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
613 /* lhi %w0,0 */
614 EMIT4_IMM(0xa7080000, REG_W0, 0);
615 /* lr %w1,%dst */
616 EMIT2(0x1800, REG_W1, dst_reg);
617 /* dlr %w0,%src */
618 EMIT4(0xb9970000, REG_W0, src_reg);
619 /* llgfr %dst,%rc */
620 EMIT4(0xb9160000, dst_reg, rc_reg);
621 break;
622 }
623 case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
624 case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
625 {
626 int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
627
628 jit->seen |= SEEN_RET0;
629 /* ltgr %src,%src (if src == 0 goto fail) */
630 EMIT4(0xb9020000, src_reg, src_reg);
631 /* jz <ret0> */
632 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
633 /* lghi %w0,0 */
634 EMIT4_IMM(0xa7090000, REG_W0, 0);
635 /* lgr %w1,%dst */
636 EMIT4(0xb9040000, REG_W1, dst_reg);
637 /* dlgr %w0,%dst */
638 EMIT4(0xb9870000, REG_W0, src_reg);
639 /* lgr %dst,%rc */
640 EMIT4(0xb9040000, dst_reg, rc_reg);
641 break;
642 }
643 case BPF_ALU | BPF_DIV | BPF_K: /* dst = (u32) dst / (u32) imm */
644 case BPF_ALU | BPF_MOD | BPF_K: /* dst = (u32) dst % (u32) imm */
645 {
646 int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
647
648 if (imm == 1) {
649 if (BPF_OP(insn->code) == BPF_MOD)
650 /* lhgi %dst,0 */
651 EMIT4_IMM(0xa7090000, dst_reg, 0);
652 break;
653 }
654 /* lhi %w0,0 */
655 EMIT4_IMM(0xa7080000, REG_W0, 0);
656 /* lr %w1,%dst */
657 EMIT2(0x1800, REG_W1, dst_reg);
658 /* dl %w0,<d(imm)>(%l) */
659 EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
660 EMIT_CONST_U32(imm));
661 /* llgfr %dst,%rc */
662 EMIT4(0xb9160000, dst_reg, rc_reg);
663 break;
664 }
665 case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
666 case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
667 {
668 int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
669
670 if (imm == 1) {
671 if (BPF_OP(insn->code) == BPF_MOD)
672 /* lhgi %dst,0 */
673 EMIT4_IMM(0xa7090000, dst_reg, 0);
674 break;
675 }
676 /* lghi %w0,0 */
677 EMIT4_IMM(0xa7090000, REG_W0, 0);
678 /* lgr %w1,%dst */
679 EMIT4(0xb9040000, REG_W1, dst_reg);
680 /* dlg %w0,<d(imm)>(%l) */
681 EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
682 EMIT_CONST_U64(imm));
683 /* lgr %dst,%rc */
684 EMIT4(0xb9040000, dst_reg, rc_reg);
685 break;
686 }
687 /*
688 * BPF_AND
689 */
690 case BPF_ALU | BPF_AND | BPF_X: /* dst = (u32) dst & (u32) src */
691 /* nr %dst,%src */
692 EMIT2(0x1400, dst_reg, src_reg);
693 EMIT_ZERO(dst_reg);
694 break;
695 case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
696 /* ngr %dst,%src */
697 EMIT4(0xb9800000, dst_reg, src_reg);
698 break;
699 case BPF_ALU | BPF_AND | BPF_K: /* dst = (u32) dst & (u32) imm */
700 /* nilf %dst,imm */
701 EMIT6_IMM(0xc00b0000, dst_reg, imm);
702 EMIT_ZERO(dst_reg);
703 break;
704 case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
705 /* ng %dst,<d(imm)>(%l) */
706 EMIT6_DISP_LH(0xe3000000, 0x0080, dst_reg, REG_0, REG_L,
707 EMIT_CONST_U64(imm));
708 break;
709 /*
710 * BPF_OR
711 */
712 case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
713 /* or %dst,%src */
714 EMIT2(0x1600, dst_reg, src_reg);
715 EMIT_ZERO(dst_reg);
716 break;
717 case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
718 /* ogr %dst,%src */
719 EMIT4(0xb9810000, dst_reg, src_reg);
720 break;
721 case BPF_ALU | BPF_OR | BPF_K: /* dst = (u32) dst | (u32) imm */
722 /* oilf %dst,imm */
723 EMIT6_IMM(0xc00d0000, dst_reg, imm);
724 EMIT_ZERO(dst_reg);
725 break;
726 case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
727 /* og %dst,<d(imm)>(%l) */
728 EMIT6_DISP_LH(0xe3000000, 0x0081, dst_reg, REG_0, REG_L,
729 EMIT_CONST_U64(imm));
730 break;
731 /*
732 * BPF_XOR
733 */
734 case BPF_ALU | BPF_XOR | BPF_X: /* dst = (u32) dst ^ (u32) src */
735 /* xr %dst,%src */
736 EMIT2(0x1700, dst_reg, src_reg);
737 EMIT_ZERO(dst_reg);
738 break;
739 case BPF_ALU64 | BPF_XOR | BPF_X: /* dst = dst ^ src */
740 /* xgr %dst,%src */
741 EMIT4(0xb9820000, dst_reg, src_reg);
742 break;
743 case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
744 if (!imm)
745 break;
746 /* xilf %dst,imm */
747 EMIT6_IMM(0xc0070000, dst_reg, imm);
748 EMIT_ZERO(dst_reg);
749 break;
750 case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
751 /* xg %dst,<d(imm)>(%l) */
752 EMIT6_DISP_LH(0xe3000000, 0x0082, dst_reg, REG_0, REG_L,
753 EMIT_CONST_U64(imm));
754 break;
755 /*
756 * BPF_LSH
757 */
758 case BPF_ALU | BPF_LSH | BPF_X: /* dst = (u32) dst << (u32) src */
759 /* sll %dst,0(%src) */
760 EMIT4_DISP(0x89000000, dst_reg, src_reg, 0);
761 EMIT_ZERO(dst_reg);
762 break;
763 case BPF_ALU64 | BPF_LSH | BPF_X: /* dst = dst << src */
764 /* sllg %dst,%dst,0(%src) */
765 EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
766 break;
767 case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
768 if (imm == 0)
769 break;
770 /* sll %dst,imm(%r0) */
771 EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
772 EMIT_ZERO(dst_reg);
773 break;
774 case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
775 if (imm == 0)
776 break;
777 /* sllg %dst,%dst,imm(%r0) */
778 EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, REG_0, imm);
779 break;
780 /*
781 * BPF_RSH
782 */
783 case BPF_ALU | BPF_RSH | BPF_X: /* dst = (u32) dst >> (u32) src */
784 /* srl %dst,0(%src) */
785 EMIT4_DISP(0x88000000, dst_reg, src_reg, 0);
786 EMIT_ZERO(dst_reg);
787 break;
788 case BPF_ALU64 | BPF_RSH | BPF_X: /* dst = dst >> src */
789 /* srlg %dst,%dst,0(%src) */
790 EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
791 break;
792 case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
793 if (imm == 0)
794 break;
795 /* srl %dst,imm(%r0) */
796 EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
797 EMIT_ZERO(dst_reg);
798 break;
799 case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
800 if (imm == 0)
801 break;
802 /* srlg %dst,%dst,imm(%r0) */
803 EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, REG_0, imm);
804 break;
805 /*
806 * BPF_ARSH
807 */
808 case BPF_ALU64 | BPF_ARSH | BPF_X: /* ((s64) dst) >>= src */
809 /* srag %dst,%dst,0(%src) */
810 EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, src_reg, 0);
811 break;
812 case BPF_ALU64 | BPF_ARSH | BPF_K: /* ((s64) dst) >>= imm */
813 if (imm == 0)
814 break;
815 /* srag %dst,%dst,imm(%r0) */
816 EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, REG_0, imm);
817 break;
818 /*
819 * BPF_NEG
820 */
821 case BPF_ALU | BPF_NEG: /* dst = (u32) -dst */
822 /* lcr %dst,%dst */
823 EMIT2(0x1300, dst_reg, dst_reg);
824 EMIT_ZERO(dst_reg);
825 break;
826 case BPF_ALU64 | BPF_NEG: /* dst = -dst */
827 /* lcgr %dst,%dst */
828 EMIT4(0xb9130000, dst_reg, dst_reg);
829 break;
830 /*
831 * BPF_FROM_BE/LE
832 */
833 case BPF_ALU | BPF_END | BPF_FROM_BE:
834 /* s390 is big endian, therefore only clear high order bytes */
835 switch (imm) {
836 case 16: /* dst = (u16) cpu_to_be16(dst) */
837 /* llghr %dst,%dst */
838 EMIT4(0xb9850000, dst_reg, dst_reg);
839 break;
840 case 32: /* dst = (u32) cpu_to_be32(dst) */
841 /* llgfr %dst,%dst */
842 EMIT4(0xb9160000, dst_reg, dst_reg);
843 break;
844 case 64: /* dst = (u64) cpu_to_be64(dst) */
845 break;
846 }
847 break;
848 case BPF_ALU | BPF_END | BPF_FROM_LE:
849 switch (imm) {
850 case 16: /* dst = (u16) cpu_to_le16(dst) */
851 /* lrvr %dst,%dst */
852 EMIT4(0xb91f0000, dst_reg, dst_reg);
853 /* srl %dst,16(%r0) */
854 EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
855 /* llghr %dst,%dst */
856 EMIT4(0xb9850000, dst_reg, dst_reg);
857 break;
858 case 32: /* dst = (u32) cpu_to_le32(dst) */
859 /* lrvr %dst,%dst */
860 EMIT4(0xb91f0000, dst_reg, dst_reg);
861 /* llgfr %dst,%dst */
862 EMIT4(0xb9160000, dst_reg, dst_reg);
863 break;
864 case 64: /* dst = (u64) cpu_to_le64(dst) */
865 /* lrvgr %dst,%dst */
866 EMIT4(0xb90f0000, dst_reg, dst_reg);
867 break;
868 }
869 break;
870 /*
871 * BPF_ST(X)
872 */
873 case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
874 /* stcy %src,off(%dst) */
875 EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
876 jit->seen |= SEEN_MEM;
877 break;
878 case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
879 /* sthy %src,off(%dst) */
880 EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
881 jit->seen |= SEEN_MEM;
882 break;
883 case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
884 /* sty %src,off(%dst) */
885 EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
886 jit->seen |= SEEN_MEM;
887 break;
888 case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
889 /* stg %src,off(%dst) */
890 EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
891 jit->seen |= SEEN_MEM;
892 break;
893 case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
894 /* lhi %w0,imm */
895 EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
896 /* stcy %w0,off(dst) */
897 EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
898 jit->seen |= SEEN_MEM;
899 break;
900 case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
901 /* lhi %w0,imm */
902 EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
903 /* sthy %w0,off(dst) */
904 EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
905 jit->seen |= SEEN_MEM;
906 break;
907 case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
908 /* llilf %w0,imm */
909 EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
910 /* sty %w0,off(%dst) */
911 EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
912 jit->seen |= SEEN_MEM;
913 break;
914 case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
915 /* lgfi %w0,imm */
916 EMIT6_IMM(0xc0010000, REG_W0, imm);
917 /* stg %w0,off(%dst) */
918 EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
919 jit->seen |= SEEN_MEM;
920 break;
921 /*
922 * BPF_STX XADD (atomic_add)
923 */
924 case BPF_STX | BPF_XADD | BPF_W: /* *(u32 *)(dst + off) += src */
925 /* laal %w0,%src,off(%dst) */
926 EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W0, src_reg,
927 dst_reg, off);
928 jit->seen |= SEEN_MEM;
929 break;
930 case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */
931 /* laalg %w0,%src,off(%dst) */
932 EMIT6_DISP_LH(0xeb000000, 0x00ea, REG_W0, src_reg,
933 dst_reg, off);
934 jit->seen |= SEEN_MEM;
935 break;
936 /*
937 * BPF_LDX
938 */
939 case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
940 /* llgc %dst,0(off,%src) */
941 EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
942 jit->seen |= SEEN_MEM;
943 break;
944 case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
945 /* llgh %dst,0(off,%src) */
946 EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
947 jit->seen |= SEEN_MEM;
948 break;
949 case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
950 /* llgf %dst,off(%src) */
951 jit->seen |= SEEN_MEM;
952 EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
953 break;
954 case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
955 /* lg %dst,0(off,%src) */
956 jit->seen |= SEEN_MEM;
957 EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
958 break;
959 /*
960 * BPF_JMP / CALL
961 */
962 case BPF_JMP | BPF_CALL:
963 {
964 /*
965 * b0 = (__bpf_call_base + imm)(b1, b2, b3, b4, b5)
966 */
967 const u64 func = (u64)__bpf_call_base + imm;
968
969 REG_SET_SEEN(BPF_REG_5);
970 jit->seen |= SEEN_FUNC;
971 /* lg %w1,<d(imm)>(%l) */
972 EMIT6_DISP_LH(0xe3000000, 0x0004, REG_W1, REG_0, REG_L,
973 EMIT_CONST_U64(func));
974 /* basr %r14,%w1 */
975 EMIT2(0x0d00, REG_14, REG_W1);
976 /* lgr %b0,%r2: load return value into %b0 */
977 EMIT4(0xb9040000, BPF_REG_0, REG_2);
978 if (bpf_helper_changes_skb_data((void *)func)) {
979 jit->seen |= SEEN_SKB_CHANGE;
980 /* lg %b1,ST_OFF_SKBP(%r15) */
981 EMIT6_DISP_LH(0xe3000000, 0x0004, BPF_REG_1, REG_0,
982 REG_15, STK_OFF_SKBP);
983 emit_load_skb_data_hlen(jit);
984 }
985 break;
986 }
987 case BPF_JMP | BPF_CALL | BPF_X:
988 /*
989 * Implicit input:
990 * B1: pointer to ctx
991 * B2: pointer to bpf_array
992 * B3: index in bpf_array
993 */
994 jit->seen |= SEEN_TAIL_CALL;
995
996 /*
997 * if (index >= array->map.max_entries)
998 * goto out;
999 */
1000
1001 /* llgf %w1,map.max_entries(%b2) */
1002 EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
1003 offsetof(struct bpf_array, map.max_entries));
1004 /* clgrj %b3,%w1,0xa,label0: if %b3 >= %w1 goto out */
1005 EMIT6_PCREL_LABEL(0xec000000, 0x0065, BPF_REG_3,
1006 REG_W1, 0, 0xa);
1007
1008 /*
1009 * if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
1010 * goto out;
1011 */
1012
1013 if (jit->seen & SEEN_STACK)
1014 off = STK_OFF_TCCNT + STK_OFF;
1015 else
1016 off = STK_OFF_TCCNT;
1017 /* lhi %w0,1 */
1018 EMIT4_IMM(0xa7080000, REG_W0, 1);
1019 /* laal %w1,%w0,off(%r15) */
1020 EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off);
1021 /* clij %w1,MAX_TAIL_CALL_CNT,0x2,label0 */
1022 EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007f, REG_W1,
1023 MAX_TAIL_CALL_CNT, 0, 0x2);
1024
1025 /*
1026 * prog = array->ptrs[index];
1027 * if (prog == NULL)
1028 * goto out;
1029 */
1030
1031 /* sllg %r1,%b3,3: %r1 = index * 8 */
1032 EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, BPF_REG_3, REG_0, 3);
1033 /* lg %r1,prog(%b2,%r1) */
1034 EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, BPF_REG_2,
1035 REG_1, offsetof(struct bpf_array, ptrs));
1036 /* clgij %r1,0,0x8,label0 */
1037 EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007d, REG_1, 0, 0, 0x8);
1038
1039 /*
1040 * Restore registers before calling function
1041 */
1042 save_restore_regs(jit, REGS_RESTORE);
1043
1044 /*
1045 * goto *(prog->bpf_func + tail_call_start);
1046 */
1047
1048 /* lg %r1,bpf_func(%r1) */
1049 EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0,
1050 offsetof(struct bpf_prog, bpf_func));
1051 /* bc 0xf,tail_call_start(%r1) */
1052 _EMIT4(0x47f01000 + jit->tail_call_start);
1053 /* out: */
1054 jit->labels[0] = jit->prg;
1055 break;
1056 case BPF_JMP | BPF_EXIT: /* return b0 */
1057 last = (i == fp->len - 1) ? 1 : 0;
1058 if (last && !(jit->seen & SEEN_RET0))
1059 break;
1060 /* j <exit> */
1061 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
1062 break;
1063 /*
1064 * Branch relative (number of skipped instructions) to offset on
1065 * condition.
1066 *
1067 * Condition code to mask mapping:
1068 *
1069 * CC | Description | Mask
1070 * ------------------------------
1071 * 0 | Operands equal | 8
1072 * 1 | First operand low | 4
1073 * 2 | First operand high | 2
1074 * 3 | Unused | 1
1075 *
1076 * For s390x relative branches: ip = ip + off_bytes
1077 * For BPF relative branches: insn = insn + off_insns + 1
1078 *
1079 * For example for s390x with offset 0 we jump to the branch
1080 * instruction itself (loop) and for BPF with offset 0 we
1081 * branch to the instruction behind the branch.
1082 */
1083 case BPF_JMP | BPF_JA: /* if (true) */
1084 mask = 0xf000; /* j */
1085 goto branch_oc;
1086 case BPF_JMP | BPF_JSGT | BPF_K: /* ((s64) dst > (s64) imm) */
1087 mask = 0x2000; /* jh */
1088 goto branch_ks;
1089 case BPF_JMP | BPF_JSGE | BPF_K: /* ((s64) dst >= (s64) imm) */
1090 mask = 0xa000; /* jhe */
1091 goto branch_ks;
1092 case BPF_JMP | BPF_JGT | BPF_K: /* (dst_reg > imm) */
1093 mask = 0x2000; /* jh */
1094 goto branch_ku;
1095 case BPF_JMP | BPF_JGE | BPF_K: /* (dst_reg >= imm) */
1096 mask = 0xa000; /* jhe */
1097 goto branch_ku;
1098 case BPF_JMP | BPF_JNE | BPF_K: /* (dst_reg != imm) */
1099 mask = 0x7000; /* jne */
1100 goto branch_ku;
1101 case BPF_JMP | BPF_JEQ | BPF_K: /* (dst_reg == imm) */
1102 mask = 0x8000; /* je */
1103 goto branch_ku;
1104 case BPF_JMP | BPF_JSET | BPF_K: /* (dst_reg & imm) */
1105 mask = 0x7000; /* jnz */
1106 /* lgfi %w1,imm (load sign extend imm) */
1107 EMIT6_IMM(0xc0010000, REG_W1, imm);
1108 /* ngr %w1,%dst */
1109 EMIT4(0xb9800000, REG_W1, dst_reg);
1110 goto branch_oc;
1111
1112 case BPF_JMP | BPF_JSGT | BPF_X: /* ((s64) dst > (s64) src) */
1113 mask = 0x2000; /* jh */
1114 goto branch_xs;
1115 case BPF_JMP | BPF_JSGE | BPF_X: /* ((s64) dst >= (s64) src) */
1116 mask = 0xa000; /* jhe */
1117 goto branch_xs;
1118 case BPF_JMP | BPF_JGT | BPF_X: /* (dst > src) */
1119 mask = 0x2000; /* jh */
1120 goto branch_xu;
1121 case BPF_JMP | BPF_JGE | BPF_X: /* (dst >= src) */
1122 mask = 0xa000; /* jhe */
1123 goto branch_xu;
1124 case BPF_JMP | BPF_JNE | BPF_X: /* (dst != src) */
1125 mask = 0x7000; /* jne */
1126 goto branch_xu;
1127 case BPF_JMP | BPF_JEQ | BPF_X: /* (dst == src) */
1128 mask = 0x8000; /* je */
1129 goto branch_xu;
1130 case BPF_JMP | BPF_JSET | BPF_X: /* (dst & src) */
1131 mask = 0x7000; /* jnz */
1132 /* ngrk %w1,%dst,%src */
1133 EMIT4_RRF(0xb9e40000, REG_W1, dst_reg, src_reg);
1134 goto branch_oc;
1135 branch_ks:
1136 /* lgfi %w1,imm (load sign extend imm) */
1137 EMIT6_IMM(0xc0010000, REG_W1, imm);
1138 /* cgrj %dst,%w1,mask,off */
1139 EMIT6_PCREL(0xec000000, 0x0064, dst_reg, REG_W1, i, off, mask);
1140 break;
1141 branch_ku:
1142 /* lgfi %w1,imm (load sign extend imm) */
1143 EMIT6_IMM(0xc0010000, REG_W1, imm);
1144 /* clgrj %dst,%w1,mask,off */
1145 EMIT6_PCREL(0xec000000, 0x0065, dst_reg, REG_W1, i, off, mask);
1146 break;
1147 branch_xs:
1148 /* cgrj %dst,%src,mask,off */
1149 EMIT6_PCREL(0xec000000, 0x0064, dst_reg, src_reg, i, off, mask);
1150 break;
1151 branch_xu:
1152 /* clgrj %dst,%src,mask,off */
1153 EMIT6_PCREL(0xec000000, 0x0065, dst_reg, src_reg, i, off, mask);
1154 break;
1155 branch_oc:
1156 /* brc mask,jmp_off (branch instruction needs 4 bytes) */
1157 jmp_off = addrs[i + off + 1] - (addrs[i + 1] - 4);
1158 EMIT4_PCREL(0xa7040000 | mask << 8, jmp_off);
1159 break;
1160 /*
1161 * BPF_LD
1162 */
1163 case BPF_LD | BPF_ABS | BPF_B: /* b0 = *(u8 *) (skb->data+imm) */
1164 case BPF_LD | BPF_IND | BPF_B: /* b0 = *(u8 *) (skb->data+imm+src) */
1165 if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
1166 func_addr = __pa(sk_load_byte_pos);
1167 else
1168 func_addr = __pa(sk_load_byte);
1169 goto call_fn;
1170 case BPF_LD | BPF_ABS | BPF_H: /* b0 = *(u16 *) (skb->data+imm) */
1171 case BPF_LD | BPF_IND | BPF_H: /* b0 = *(u16 *) (skb->data+imm+src) */
1172 if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
1173 func_addr = __pa(sk_load_half_pos);
1174 else
1175 func_addr = __pa(sk_load_half);
1176 goto call_fn;
1177 case BPF_LD | BPF_ABS | BPF_W: /* b0 = *(u32 *) (skb->data+imm) */
1178 case BPF_LD | BPF_IND | BPF_W: /* b0 = *(u32 *) (skb->data+imm+src) */
1179 if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
1180 func_addr = __pa(sk_load_word_pos);
1181 else
1182 func_addr = __pa(sk_load_word);
1183 goto call_fn;
1184 call_fn:
1185 jit->seen |= SEEN_SKB | SEEN_RET0 | SEEN_FUNC;
1186 REG_SET_SEEN(REG_14); /* Return address of possible func call */
1187
1188 /*
1189 * Implicit input:
1190 * BPF_REG_6 (R7) : skb pointer
1191 * REG_SKB_DATA (R12): skb data pointer
1192 *
1193 * Calculated input:
1194 * BPF_REG_2 (R3) : offset of byte(s) to fetch in skb
1195 * BPF_REG_5 (R6) : return address
1196 *
1197 * Output:
1198 * BPF_REG_0 (R14): data read from skb
1199 *
1200 * Scratch registers (BPF_REG_1-5)
1201 */
1202
1203 /* Call function: llilf %w1,func_addr */
1204 EMIT6_IMM(0xc00f0000, REG_W1, func_addr);
1205
1206 /* Offset: lgfi %b2,imm */
1207 EMIT6_IMM(0xc0010000, BPF_REG_2, imm);
1208 if (BPF_MODE(insn->code) == BPF_IND)
1209 /* agfr %b2,%src (%src is s32 here) */
1210 EMIT4(0xb9180000, BPF_REG_2, src_reg);
1211
1212 /* basr %b5,%w1 (%b5 is call saved) */
1213 EMIT2(0x0d00, BPF_REG_5, REG_W1);
1214
1215 /*
1216 * Note: For fast access we jump directly after the
1217 * jnz instruction from bpf_jit.S
1218 */
1219 /* jnz <ret0> */
1220 EMIT4_PCREL(0xa7740000, jit->ret0_ip - jit->prg);
1221 break;
1222 default: /* too complex, give up */
1223 pr_err("Unknown opcode %02x\n", insn->code);
1224 return -1;
1225 }
1226 return insn_count;
1227 }
1228
1229 /*
1230 * Compile eBPF program into s390x code
1231 */
1232 static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
1233 {
1234 int i, insn_count;
1235
1236 jit->lit = jit->lit_start;
1237 jit->prg = 0;
1238
1239 bpf_jit_prologue(jit);
1240 for (i = 0; i < fp->len; i += insn_count) {
1241 insn_count = bpf_jit_insn(jit, fp, i);
1242 if (insn_count < 0)
1243 return -1;
1244 jit->addrs[i + 1] = jit->prg; /* Next instruction address */
1245 }
1246 bpf_jit_epilogue(jit);
1247
1248 jit->lit_start = jit->prg;
1249 jit->size = jit->lit;
1250 jit->size_prg = jit->prg;
1251 return 0;
1252 }
1253
1254 /*
1255 * Classic BPF function stub. BPF programs will be converted into
1256 * eBPF and then bpf_int_jit_compile() will be called.
1257 */
1258 void bpf_jit_compile(struct bpf_prog *fp)
1259 {
1260 }
1261
1262 /*
1263 * Compile eBPF program "fp"
1264 */
1265 void bpf_int_jit_compile(struct bpf_prog *fp)
1266 {
1267 struct bpf_binary_header *header;
1268 struct bpf_jit jit;
1269 int pass;
1270
1271 if (!bpf_jit_enable)
1272 return;
1273 memset(&jit, 0, sizeof(jit));
1274 jit.addrs = kcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL);
1275 if (jit.addrs == NULL)
1276 return;
1277 /*
1278 * Three initial passes:
1279 * - 1/2: Determine clobbered registers
1280 * - 3: Calculate program size and addrs arrray
1281 */
1282 for (pass = 1; pass <= 3; pass++) {
1283 if (bpf_jit_prog(&jit, fp))
1284 goto free_addrs;
1285 }
1286 /*
1287 * Final pass: Allocate and generate program
1288 */
1289 if (jit.size >= BPF_SIZE_MAX)
1290 goto free_addrs;
1291 header = bpf_jit_binary_alloc(jit.size, &jit.prg_buf, 2, jit_fill_hole);
1292 if (!header)
1293 goto free_addrs;
1294 if (bpf_jit_prog(&jit, fp))
1295 goto free_addrs;
1296 if (bpf_jit_enable > 1) {
1297 bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
1298 if (jit.prg_buf)
1299 print_fn_code(jit.prg_buf, jit.size_prg);
1300 }
1301 if (jit.prg_buf) {
1302 set_memory_ro((unsigned long)header, header->pages);
1303 fp->bpf_func = (void *) jit.prg_buf;
1304 fp->jited = 1;
1305 }
1306 free_addrs:
1307 kfree(jit.addrs);
1308 }
1309
1310 /*
1311 * Free eBPF program
1312 */
1313 void bpf_jit_free(struct bpf_prog *fp)
1314 {
1315 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
1316 struct bpf_binary_header *header = (void *)addr;
1317
1318 if (!fp->jited)
1319 goto free_filter;
1320
1321 set_memory_rw(addr, header->pages);
1322 bpf_jit_binary_free(header);
1323
1324 free_filter:
1325 bpf_prog_unlock_free(fp);
1326 }
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