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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Just-In-Time compiler for eBPF filters on MIPS
4 *
5 * Copyright (c) 2017 Cavium, Inc.
6 *
7 * Based on code from:
8 *
9 * Copyright (c) 2014 Imagination Technologies Ltd.
10 * Author: Markos Chandras <markos.chandras@imgtec.com>
11 */
12
13#include <linux/bitops.h>
14#include <linux/errno.h>
15#include <linux/filter.h>
16#include <linux/bpf.h>
17#include <linux/slab.h>
18#include <asm/bitops.h>
19#include <asm/byteorder.h>
20#include <asm/cacheflush.h>
21#include <asm/cpu-features.h>
22#include <asm/isa-rev.h>
23#include <asm/uasm.h>
24
25/* Registers used by JIT */
26#define MIPS_R_ZERO 0
27#define MIPS_R_AT 1
28#define MIPS_R_V0 2 /* BPF_R0 */
29#define MIPS_R_V1 3
30#define MIPS_R_A0 4 /* BPF_R1 */
31#define MIPS_R_A1 5 /* BPF_R2 */
32#define MIPS_R_A2 6 /* BPF_R3 */
33#define MIPS_R_A3 7 /* BPF_R4 */
34#define MIPS_R_A4 8 /* BPF_R5 */
35#define MIPS_R_T4 12 /* BPF_AX */
36#define MIPS_R_T5 13
37#define MIPS_R_T6 14
38#define MIPS_R_T7 15
39#define MIPS_R_S0 16 /* BPF_R6 */
40#define MIPS_R_S1 17 /* BPF_R7 */
41#define MIPS_R_S2 18 /* BPF_R8 */
42#define MIPS_R_S3 19 /* BPF_R9 */
43#define MIPS_R_S4 20 /* BPF_TCC */
44#define MIPS_R_S5 21
45#define MIPS_R_S6 22
46#define MIPS_R_S7 23
47#define MIPS_R_T8 24
48#define MIPS_R_T9 25
49#define MIPS_R_SP 29
50#define MIPS_R_RA 31
51
52/* eBPF flags */
53#define EBPF_SAVE_S0 BIT(0)
54#define EBPF_SAVE_S1 BIT(1)
55#define EBPF_SAVE_S2 BIT(2)
56#define EBPF_SAVE_S3 BIT(3)
57#define EBPF_SAVE_S4 BIT(4)
58#define EBPF_SAVE_RA BIT(5)
59#define EBPF_SEEN_FP BIT(6)
60#define EBPF_SEEN_TC BIT(7)
61#define EBPF_TCC_IN_V1 BIT(8)
62
63/*
64 * For the mips64 ISA, we need to track the value range or type for
65 * each JIT register. The BPF machine requires zero extended 32-bit
66 * values, but the mips64 ISA requires sign extended 32-bit values.
67 * At each point in the BPF program we track the state of every
68 * register so that we can zero extend or sign extend as the BPF
69 * semantics require.
70 */
71enum reg_val_type {
72 /* uninitialized */
73 REG_UNKNOWN,
74 /* not known to be 32-bit compatible. */
75 REG_64BIT,
76 /* 32-bit compatible, no truncation needed for 64-bit ops. */
77 REG_64BIT_32BIT,
78 /* 32-bit compatible, need truncation for 64-bit ops. */
79 REG_32BIT,
80 /* 32-bit no sign/zero extension needed. */
81 REG_32BIT_POS
82};
83
84/*
85 * high bit of offsets indicates if long branch conversion done at
86 * this insn.
87 */
88#define OFFSETS_B_CONV BIT(31)
89
90/**
91 * struct jit_ctx - JIT context
92 * @skf: The sk_filter
93 * @stack_size: eBPF stack size
94 * @idx: Instruction index
95 * @flags: JIT flags
96 * @offsets: Instruction offsets
97 * @target: Memory location for the compiled filter
98 * @reg_val_types Packed enum reg_val_type for each register.
99 */
100struct jit_ctx {
101 const struct bpf_prog *skf;
102 int stack_size;
103 u32 idx;
104 u32 flags;
105 u32 *offsets;
106 u32 *target;
107 u64 *reg_val_types;
108 unsigned int long_b_conversion:1;
109 unsigned int gen_b_offsets:1;
110 unsigned int use_bbit_insns:1;
111};
112
113static void set_reg_val_type(u64 *rvt, int reg, enum reg_val_type type)
114{
115 *rvt &= ~(7ull << (reg * 3));
116 *rvt |= ((u64)type << (reg * 3));
117}
118
119static enum reg_val_type get_reg_val_type(const struct jit_ctx *ctx,
120 int index, int reg)
121{
122 return (ctx->reg_val_types[index] >> (reg * 3)) & 7;
123}
124
125/* Simply emit the instruction if the JIT memory space has been allocated */
126#define emit_instr_long(ctx, func64, func32, ...) \
127do { \
128 if ((ctx)->target != NULL) { \
129 u32 *p = &(ctx)->target[ctx->idx]; \
130 if (IS_ENABLED(CONFIG_64BIT)) \
131 uasm_i_##func64(&p, ##__VA_ARGS__); \
132 else \
133 uasm_i_##func32(&p, ##__VA_ARGS__); \
134 } \
135 (ctx)->idx++; \
136} while (0)
137
138#define emit_instr(ctx, func, ...) \
139 emit_instr_long(ctx, func, func, ##__VA_ARGS__)
140
141static unsigned int j_target(struct jit_ctx *ctx, int target_idx)
142{
143 unsigned long target_va, base_va;
144 unsigned int r;
145
146 if (!ctx->target)
147 return 0;
148
149 base_va = (unsigned long)ctx->target;
150 target_va = base_va + (ctx->offsets[target_idx] & ~OFFSETS_B_CONV);
151
152 if ((base_va & ~0x0ffffffful) != (target_va & ~0x0ffffffful))
153 return (unsigned int)-1;
154 r = target_va & 0x0ffffffful;
155 return r;
156}
157
158/* Compute the immediate value for PC-relative branches. */
159static u32 b_imm(unsigned int tgt, struct jit_ctx *ctx)
160{
161 if (!ctx->gen_b_offsets)
162 return 0;
163
164 /*
165 * We want a pc-relative branch. tgt is the instruction offset
166 * we want to jump to.
167
168 * Branch on MIPS:
169 * I: target_offset <- sign_extend(offset)
170 * I+1: PC += target_offset (delay slot)
171 *
172 * ctx->idx currently points to the branch instruction
173 * but the offset is added to the delay slot so we need
174 * to subtract 4.
175 */
176 return (ctx->offsets[tgt] & ~OFFSETS_B_CONV) -
177 (ctx->idx * 4) - 4;
178}
179
180enum which_ebpf_reg {
181 src_reg,
182 src_reg_no_fp,
183 dst_reg,
184 dst_reg_fp_ok
185};
186
187/*
188 * For eBPF, the register mapping naturally falls out of the
189 * requirements of eBPF and the MIPS n64 ABI. We don't maintain a
190 * separate frame pointer, so BPF_REG_10 relative accesses are
191 * adjusted to be $sp relative.
192 */
193static int ebpf_to_mips_reg(struct jit_ctx *ctx,
194 const struct bpf_insn *insn,
195 enum which_ebpf_reg w)
196{
197 int ebpf_reg = (w == src_reg || w == src_reg_no_fp) ?
198 insn->src_reg : insn->dst_reg;
199
200 switch (ebpf_reg) {
201 case BPF_REG_0:
202 return MIPS_R_V0;
203 case BPF_REG_1:
204 return MIPS_R_A0;
205 case BPF_REG_2:
206 return MIPS_R_A1;
207 case BPF_REG_3:
208 return MIPS_R_A2;
209 case BPF_REG_4:
210 return MIPS_R_A3;
211 case BPF_REG_5:
212 return MIPS_R_A4;
213 case BPF_REG_6:
214 ctx->flags |= EBPF_SAVE_S0;
215 return MIPS_R_S0;
216 case BPF_REG_7:
217 ctx->flags |= EBPF_SAVE_S1;
218 return MIPS_R_S1;
219 case BPF_REG_8:
220 ctx->flags |= EBPF_SAVE_S2;
221 return MIPS_R_S2;
222 case BPF_REG_9:
223 ctx->flags |= EBPF_SAVE_S3;
224 return MIPS_R_S3;
225 case BPF_REG_10:
226 if (w == dst_reg || w == src_reg_no_fp)
227 goto bad_reg;
228 ctx->flags |= EBPF_SEEN_FP;
229 /*
230 * Needs special handling, return something that
231 * cannot be clobbered just in case.
232 */
233 return MIPS_R_ZERO;
234 case BPF_REG_AX:
235 return MIPS_R_T4;
236 default:
237bad_reg:
238 WARN(1, "Illegal bpf reg: %d\n", ebpf_reg);
239 return -EINVAL;
240 }
241}
242/*
243 * eBPF stack frame will be something like:
244 *
245 * Entry $sp ------> +--------------------------------+
246 * | $ra (optional) |
247 * +--------------------------------+
248 * | $s0 (optional) |
249 * +--------------------------------+
250 * | $s1 (optional) |
251 * +--------------------------------+
252 * | $s2 (optional) |
253 * +--------------------------------+
254 * | $s3 (optional) |
255 * +--------------------------------+
256 * | $s4 (optional) |
257 * +--------------------------------+
258 * | tmp-storage (if $ra saved) |
259 * $sp + tmp_offset --> +--------------------------------+ <--BPF_REG_10
260 * | BPF_REG_10 relative storage |
261 * | MAX_BPF_STACK (optional) |
262 * | . |
263 * | . |
264 * | . |
265 * $sp --------> +--------------------------------+
266 *
267 * If BPF_REG_10 is never referenced, then the MAX_BPF_STACK sized
268 * area is not allocated.
269 */
270static int gen_int_prologue(struct jit_ctx *ctx)
271{
272 int stack_adjust = 0;
273 int store_offset;
274 int locals_size;
275
276 if (ctx->flags & EBPF_SAVE_RA)
277 /*
278 * If RA we are doing a function call and may need
279 * extra 8-byte tmp area.
280 */
281 stack_adjust += 2 * sizeof(long);
282 if (ctx->flags & EBPF_SAVE_S0)
283 stack_adjust += sizeof(long);
284 if (ctx->flags & EBPF_SAVE_S1)
285 stack_adjust += sizeof(long);
286 if (ctx->flags & EBPF_SAVE_S2)
287 stack_adjust += sizeof(long);
288 if (ctx->flags & EBPF_SAVE_S3)
289 stack_adjust += sizeof(long);
290 if (ctx->flags & EBPF_SAVE_S4)
291 stack_adjust += sizeof(long);
292
293 BUILD_BUG_ON(MAX_BPF_STACK & 7);
294 locals_size = (ctx->flags & EBPF_SEEN_FP) ? MAX_BPF_STACK : 0;
295
296 stack_adjust += locals_size;
297
298 ctx->stack_size = stack_adjust;
299
300 /*
301 * First instruction initializes the tail call count (TCC).
302 * On tail call we skip this instruction, and the TCC is
303 * passed in $v1 from the caller.
304 */
305 emit_instr(ctx, addiu, MIPS_R_V1, MIPS_R_ZERO, MAX_TAIL_CALL_CNT);
306 if (stack_adjust)
307 emit_instr_long(ctx, daddiu, addiu,
308 MIPS_R_SP, MIPS_R_SP, -stack_adjust);
309 else
310 return 0;
311
312 store_offset = stack_adjust - sizeof(long);
313
314 if (ctx->flags & EBPF_SAVE_RA) {
315 emit_instr_long(ctx, sd, sw,
316 MIPS_R_RA, store_offset, MIPS_R_SP);
317 store_offset -= sizeof(long);
318 }
319 if (ctx->flags & EBPF_SAVE_S0) {
320 emit_instr_long(ctx, sd, sw,
321 MIPS_R_S0, store_offset, MIPS_R_SP);
322 store_offset -= sizeof(long);
323 }
324 if (ctx->flags & EBPF_SAVE_S1) {
325 emit_instr_long(ctx, sd, sw,
326 MIPS_R_S1, store_offset, MIPS_R_SP);
327 store_offset -= sizeof(long);
328 }
329 if (ctx->flags & EBPF_SAVE_S2) {
330 emit_instr_long(ctx, sd, sw,
331 MIPS_R_S2, store_offset, MIPS_R_SP);
332 store_offset -= sizeof(long);
333 }
334 if (ctx->flags & EBPF_SAVE_S3) {
335 emit_instr_long(ctx, sd, sw,
336 MIPS_R_S3, store_offset, MIPS_R_SP);
337 store_offset -= sizeof(long);
338 }
339 if (ctx->flags & EBPF_SAVE_S4) {
340 emit_instr_long(ctx, sd, sw,
341 MIPS_R_S4, store_offset, MIPS_R_SP);
342 store_offset -= sizeof(long);
343 }
344
345 if ((ctx->flags & EBPF_SEEN_TC) && !(ctx->flags & EBPF_TCC_IN_V1))
346 emit_instr_long(ctx, daddu, addu,
347 MIPS_R_S4, MIPS_R_V1, MIPS_R_ZERO);
348
349 return 0;
350}
351
352static int build_int_epilogue(struct jit_ctx *ctx, int dest_reg)
353{
354 const struct bpf_prog *prog = ctx->skf;
355 int stack_adjust = ctx->stack_size;
356 int store_offset = stack_adjust - sizeof(long);
357 enum reg_val_type td;
358 int r0 = MIPS_R_V0;
359
360 if (dest_reg == MIPS_R_RA) {
361 /* Don't let zero extended value escape. */
362 td = get_reg_val_type(ctx, prog->len, BPF_REG_0);
363 if (td == REG_64BIT)
364 emit_instr(ctx, sll, r0, r0, 0);
365 }
366
367 if (ctx->flags & EBPF_SAVE_RA) {
368 emit_instr_long(ctx, ld, lw,
369 MIPS_R_RA, store_offset, MIPS_R_SP);
370 store_offset -= sizeof(long);
371 }
372 if (ctx->flags & EBPF_SAVE_S0) {
373 emit_instr_long(ctx, ld, lw,
374 MIPS_R_S0, store_offset, MIPS_R_SP);
375 store_offset -= sizeof(long);
376 }
377 if (ctx->flags & EBPF_SAVE_S1) {
378 emit_instr_long(ctx, ld, lw,
379 MIPS_R_S1, store_offset, MIPS_R_SP);
380 store_offset -= sizeof(long);
381 }
382 if (ctx->flags & EBPF_SAVE_S2) {
383 emit_instr_long(ctx, ld, lw,
384 MIPS_R_S2, store_offset, MIPS_R_SP);
385 store_offset -= sizeof(long);
386 }
387 if (ctx->flags & EBPF_SAVE_S3) {
388 emit_instr_long(ctx, ld, lw,
389 MIPS_R_S3, store_offset, MIPS_R_SP);
390 store_offset -= sizeof(long);
391 }
392 if (ctx->flags & EBPF_SAVE_S4) {
393 emit_instr_long(ctx, ld, lw,
394 MIPS_R_S4, store_offset, MIPS_R_SP);
395 store_offset -= sizeof(long);
396 }
397 emit_instr(ctx, jr, dest_reg);
398
399 if (stack_adjust)
400 emit_instr_long(ctx, daddiu, addiu,
401 MIPS_R_SP, MIPS_R_SP, stack_adjust);
402 else
403 emit_instr(ctx, nop);
404
405 return 0;
406}
407
408static void gen_imm_to_reg(const struct bpf_insn *insn, int reg,
409 struct jit_ctx *ctx)
410{
411 if (insn->imm >= S16_MIN && insn->imm <= S16_MAX) {
412 emit_instr(ctx, addiu, reg, MIPS_R_ZERO, insn->imm);
413 } else {
414 int lower = (s16)(insn->imm & 0xffff);
415 int upper = insn->imm - lower;
416
417 emit_instr(ctx, lui, reg, upper >> 16);
418 emit_instr(ctx, addiu, reg, reg, lower);
419 }
420}
421
422static int gen_imm_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
423 int idx)
424{
425 int upper_bound, lower_bound;
426 int dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
427
428 if (dst < 0)
429 return dst;
430
431 switch (BPF_OP(insn->code)) {
432 case BPF_MOV:
433 case BPF_ADD:
434 upper_bound = S16_MAX;
435 lower_bound = S16_MIN;
436 break;
437 case BPF_SUB:
438 upper_bound = -(int)S16_MIN;
439 lower_bound = -(int)S16_MAX;
440 break;
441 case BPF_AND:
442 case BPF_OR:
443 case BPF_XOR:
444 upper_bound = 0xffff;
445 lower_bound = 0;
446 break;
447 case BPF_RSH:
448 case BPF_LSH:
449 case BPF_ARSH:
450 /* Shift amounts are truncated, no need for bounds */
451 upper_bound = S32_MAX;
452 lower_bound = S32_MIN;
453 break;
454 default:
455 return -EINVAL;
456 }
457
458 /*
459 * Immediate move clobbers the register, so no sign/zero
460 * extension needed.
461 */
462 if (BPF_CLASS(insn->code) == BPF_ALU64 &&
463 BPF_OP(insn->code) != BPF_MOV &&
464 get_reg_val_type(ctx, idx, insn->dst_reg) == REG_32BIT)
465 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
466 /* BPF_ALU | BPF_LSH doesn't need separate sign extension */
467 if (BPF_CLASS(insn->code) == BPF_ALU &&
468 BPF_OP(insn->code) != BPF_LSH &&
469 BPF_OP(insn->code) != BPF_MOV &&
470 get_reg_val_type(ctx, idx, insn->dst_reg) != REG_32BIT)
471 emit_instr(ctx, sll, dst, dst, 0);
472
473 if (insn->imm >= lower_bound && insn->imm <= upper_bound) {
474 /* single insn immediate case */
475 switch (BPF_OP(insn->code) | BPF_CLASS(insn->code)) {
476 case BPF_ALU64 | BPF_MOV:
477 emit_instr(ctx, daddiu, dst, MIPS_R_ZERO, insn->imm);
478 break;
479 case BPF_ALU64 | BPF_AND:
480 case BPF_ALU | BPF_AND:
481 emit_instr(ctx, andi, dst, dst, insn->imm);
482 break;
483 case BPF_ALU64 | BPF_OR:
484 case BPF_ALU | BPF_OR:
485 emit_instr(ctx, ori, dst, dst, insn->imm);
486 break;
487 case BPF_ALU64 | BPF_XOR:
488 case BPF_ALU | BPF_XOR:
489 emit_instr(ctx, xori, dst, dst, insn->imm);
490 break;
491 case BPF_ALU64 | BPF_ADD:
492 emit_instr(ctx, daddiu, dst, dst, insn->imm);
493 break;
494 case BPF_ALU64 | BPF_SUB:
495 emit_instr(ctx, daddiu, dst, dst, -insn->imm);
496 break;
497 case BPF_ALU64 | BPF_RSH:
498 emit_instr(ctx, dsrl_safe, dst, dst, insn->imm & 0x3f);
499 break;
500 case BPF_ALU | BPF_RSH:
501 emit_instr(ctx, srl, dst, dst, insn->imm & 0x1f);
502 break;
503 case BPF_ALU64 | BPF_LSH:
504 emit_instr(ctx, dsll_safe, dst, dst, insn->imm & 0x3f);
505 break;
506 case BPF_ALU | BPF_LSH:
507 emit_instr(ctx, sll, dst, dst, insn->imm & 0x1f);
508 break;
509 case BPF_ALU64 | BPF_ARSH:
510 emit_instr(ctx, dsra_safe, dst, dst, insn->imm & 0x3f);
511 break;
512 case BPF_ALU | BPF_ARSH:
513 emit_instr(ctx, sra, dst, dst, insn->imm & 0x1f);
514 break;
515 case BPF_ALU | BPF_MOV:
516 emit_instr(ctx, addiu, dst, MIPS_R_ZERO, insn->imm);
517 break;
518 case BPF_ALU | BPF_ADD:
519 emit_instr(ctx, addiu, dst, dst, insn->imm);
520 break;
521 case BPF_ALU | BPF_SUB:
522 emit_instr(ctx, addiu, dst, dst, -insn->imm);
523 break;
524 default:
525 return -EINVAL;
526 }
527 } else {
528 /* multi insn immediate case */
529 if (BPF_OP(insn->code) == BPF_MOV) {
530 gen_imm_to_reg(insn, dst, ctx);
531 } else {
532 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
533 switch (BPF_OP(insn->code) | BPF_CLASS(insn->code)) {
534 case BPF_ALU64 | BPF_AND:
535 case BPF_ALU | BPF_AND:
536 emit_instr(ctx, and, dst, dst, MIPS_R_AT);
537 break;
538 case BPF_ALU64 | BPF_OR:
539 case BPF_ALU | BPF_OR:
540 emit_instr(ctx, or, dst, dst, MIPS_R_AT);
541 break;
542 case BPF_ALU64 | BPF_XOR:
543 case BPF_ALU | BPF_XOR:
544 emit_instr(ctx, xor, dst, dst, MIPS_R_AT);
545 break;
546 case BPF_ALU64 | BPF_ADD:
547 emit_instr(ctx, daddu, dst, dst, MIPS_R_AT);
548 break;
549 case BPF_ALU64 | BPF_SUB:
550 emit_instr(ctx, dsubu, dst, dst, MIPS_R_AT);
551 break;
552 case BPF_ALU | BPF_ADD:
553 emit_instr(ctx, addu, dst, dst, MIPS_R_AT);
554 break;
555 case BPF_ALU | BPF_SUB:
556 emit_instr(ctx, subu, dst, dst, MIPS_R_AT);
557 break;
558 default:
559 return -EINVAL;
560 }
561 }
562 }
563
564 return 0;
565}
566
567static void emit_const_to_reg(struct jit_ctx *ctx, int dst, u64 value)
568{
569 if (value >= 0xffffffffffff8000ull || value < 0x8000ull) {
570 emit_instr(ctx, daddiu, dst, MIPS_R_ZERO, (int)value);
571 } else if (value >= 0xffffffff80000000ull ||
572 (value < 0x80000000 && value > 0xffff)) {
573 emit_instr(ctx, lui, dst, (s32)(s16)(value >> 16));
574 emit_instr(ctx, ori, dst, dst, (unsigned int)(value & 0xffff));
575 } else {
576 int i;
577 bool seen_part = false;
578 int needed_shift = 0;
579
580 for (i = 0; i < 4; i++) {
581 u64 part = (value >> (16 * (3 - i))) & 0xffff;
582
583 if (seen_part && needed_shift > 0 && (part || i == 3)) {
584 emit_instr(ctx, dsll_safe, dst, dst, needed_shift);
585 needed_shift = 0;
586 }
587 if (part) {
588 if (i == 0 || (!seen_part && i < 3 && part < 0x8000)) {
589 emit_instr(ctx, lui, dst, (s32)(s16)part);
590 needed_shift = -16;
591 } else {
592 emit_instr(ctx, ori, dst,
593 seen_part ? dst : MIPS_R_ZERO,
594 (unsigned int)part);
595 }
596 seen_part = true;
597 }
598 if (seen_part)
599 needed_shift += 16;
600 }
601 }
602}
603
604static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx)
605{
606 int off, b_off;
607 int tcc_reg;
608
609 ctx->flags |= EBPF_SEEN_TC;
610 /*
611 * if (index >= array->map.max_entries)
612 * goto out;
613 */
614 off = offsetof(struct bpf_array, map.max_entries);
615 emit_instr(ctx, lwu, MIPS_R_T5, off, MIPS_R_A1);
616 emit_instr(ctx, sltu, MIPS_R_AT, MIPS_R_T5, MIPS_R_A2);
617 b_off = b_imm(this_idx + 1, ctx);
618 emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off);
619 /*
620 * if (TCC-- < 0)
621 * goto out;
622 */
623 /* Delay slot */
624 tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4;
625 emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1);
626 b_off = b_imm(this_idx + 1, ctx);
627 emit_instr(ctx, bltz, tcc_reg, b_off);
628 /*
629 * prog = array->ptrs[index];
630 * if (prog == NULL)
631 * goto out;
632 */
633 /* Delay slot */
634 emit_instr(ctx, dsll, MIPS_R_T8, MIPS_R_A2, 3);
635 emit_instr(ctx, daddu, MIPS_R_T8, MIPS_R_T8, MIPS_R_A1);
636 off = offsetof(struct bpf_array, ptrs);
637 emit_instr(ctx, ld, MIPS_R_AT, off, MIPS_R_T8);
638 b_off = b_imm(this_idx + 1, ctx);
639 emit_instr(ctx, beq, MIPS_R_AT, MIPS_R_ZERO, b_off);
640 /* Delay slot */
641 emit_instr(ctx, nop);
642
643 /* goto *(prog->bpf_func + 4); */
644 off = offsetof(struct bpf_prog, bpf_func);
645 emit_instr(ctx, ld, MIPS_R_T9, off, MIPS_R_AT);
646 /* All systems are go... propagate TCC */
647 emit_instr(ctx, daddu, MIPS_R_V1, MIPS_R_T5, MIPS_R_ZERO);
648 /* Skip first instruction (TCC initialization) */
649 emit_instr(ctx, daddiu, MIPS_R_T9, MIPS_R_T9, 4);
650 return build_int_epilogue(ctx, MIPS_R_T9);
651}
652
653static bool is_bad_offset(int b_off)
654{
655 return b_off > 0x1ffff || b_off < -0x20000;
656}
657
658/* Returns the number of insn slots consumed. */
659static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
660 int this_idx, int exit_idx)
661{
662 int src, dst, r, td, ts, mem_off, b_off;
663 bool need_swap, did_move, cmp_eq;
664 unsigned int target = 0;
665 u64 t64;
666 s64 t64s;
667 int bpf_op = BPF_OP(insn->code);
668
669 if (IS_ENABLED(CONFIG_32BIT) && ((BPF_CLASS(insn->code) == BPF_ALU64)
670 || (bpf_op == BPF_DW)))
671 return -EINVAL;
672
673 switch (insn->code) {
674 case BPF_ALU64 | BPF_ADD | BPF_K: /* ALU64_IMM */
675 case BPF_ALU64 | BPF_SUB | BPF_K: /* ALU64_IMM */
676 case BPF_ALU64 | BPF_OR | BPF_K: /* ALU64_IMM */
677 case BPF_ALU64 | BPF_AND | BPF_K: /* ALU64_IMM */
678 case BPF_ALU64 | BPF_LSH | BPF_K: /* ALU64_IMM */
679 case BPF_ALU64 | BPF_RSH | BPF_K: /* ALU64_IMM */
680 case BPF_ALU64 | BPF_XOR | BPF_K: /* ALU64_IMM */
681 case BPF_ALU64 | BPF_ARSH | BPF_K: /* ALU64_IMM */
682 case BPF_ALU64 | BPF_MOV | BPF_K: /* ALU64_IMM */
683 case BPF_ALU | BPF_MOV | BPF_K: /* ALU32_IMM */
684 case BPF_ALU | BPF_ADD | BPF_K: /* ALU32_IMM */
685 case BPF_ALU | BPF_SUB | BPF_K: /* ALU32_IMM */
686 case BPF_ALU | BPF_OR | BPF_K: /* ALU64_IMM */
687 case BPF_ALU | BPF_AND | BPF_K: /* ALU64_IMM */
688 case BPF_ALU | BPF_LSH | BPF_K: /* ALU64_IMM */
689 case BPF_ALU | BPF_RSH | BPF_K: /* ALU64_IMM */
690 case BPF_ALU | BPF_XOR | BPF_K: /* ALU64_IMM */
691 case BPF_ALU | BPF_ARSH | BPF_K: /* ALU64_IMM */
692 r = gen_imm_insn(insn, ctx, this_idx);
693 if (r < 0)
694 return r;
695 break;
696 case BPF_ALU64 | BPF_MUL | BPF_K: /* ALU64_IMM */
697 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
698 if (dst < 0)
699 return dst;
700 if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT)
701 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
702 if (insn->imm == 1) /* Mult by 1 is a nop */
703 break;
704 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
705 if (MIPS_ISA_REV >= 6) {
706 emit_instr(ctx, dmulu, dst, dst, MIPS_R_AT);
707 } else {
708 emit_instr(ctx, dmultu, MIPS_R_AT, dst);
709 emit_instr(ctx, mflo, dst);
710 }
711 break;
712 case BPF_ALU64 | BPF_NEG | BPF_K: /* ALU64_IMM */
713 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
714 if (dst < 0)
715 return dst;
716 if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT)
717 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
718 emit_instr(ctx, dsubu, dst, MIPS_R_ZERO, dst);
719 break;
720 case BPF_ALU | BPF_MUL | BPF_K: /* ALU_IMM */
721 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
722 if (dst < 0)
723 return dst;
724 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
725 if (td == REG_64BIT) {
726 /* sign extend */
727 emit_instr(ctx, sll, dst, dst, 0);
728 }
729 if (insn->imm == 1) /* Mult by 1 is a nop */
730 break;
731 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
732 if (MIPS_ISA_REV >= 6) {
733 emit_instr(ctx, mulu, dst, dst, MIPS_R_AT);
734 } else {
735 emit_instr(ctx, multu, dst, MIPS_R_AT);
736 emit_instr(ctx, mflo, dst);
737 }
738 break;
739 case BPF_ALU | BPF_NEG | BPF_K: /* ALU_IMM */
740 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
741 if (dst < 0)
742 return dst;
743 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
744 if (td == REG_64BIT) {
745 /* sign extend */
746 emit_instr(ctx, sll, dst, dst, 0);
747 }
748 emit_instr(ctx, subu, dst, MIPS_R_ZERO, dst);
749 break;
750 case BPF_ALU | BPF_DIV | BPF_K: /* ALU_IMM */
751 case BPF_ALU | BPF_MOD | BPF_K: /* ALU_IMM */
752 if (insn->imm == 0)
753 return -EINVAL;
754 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
755 if (dst < 0)
756 return dst;
757 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
758 if (td == REG_64BIT)
759 /* sign extend */
760 emit_instr(ctx, sll, dst, dst, 0);
761 if (insn->imm == 1) {
762 /* div by 1 is a nop, mod by 1 is zero */
763 if (bpf_op == BPF_MOD)
764 emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO);
765 break;
766 }
767 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
768 if (MIPS_ISA_REV >= 6) {
769 if (bpf_op == BPF_DIV)
770 emit_instr(ctx, divu_r6, dst, dst, MIPS_R_AT);
771 else
772 emit_instr(ctx, modu, dst, dst, MIPS_R_AT);
773 break;
774 }
775 emit_instr(ctx, divu, dst, MIPS_R_AT);
776 if (bpf_op == BPF_DIV)
777 emit_instr(ctx, mflo, dst);
778 else
779 emit_instr(ctx, mfhi, dst);
780 break;
781 case BPF_ALU64 | BPF_DIV | BPF_K: /* ALU_IMM */
782 case BPF_ALU64 | BPF_MOD | BPF_K: /* ALU_IMM */
783 if (insn->imm == 0)
784 return -EINVAL;
785 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
786 if (dst < 0)
787 return dst;
788 if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT)
789 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
790 if (insn->imm == 1) {
791 /* div by 1 is a nop, mod by 1 is zero */
792 if (bpf_op == BPF_MOD)
793 emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO);
794 break;
795 }
796 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
797 if (MIPS_ISA_REV >= 6) {
798 if (bpf_op == BPF_DIV)
799 emit_instr(ctx, ddivu_r6, dst, dst, MIPS_R_AT);
800 else
801 emit_instr(ctx, modu, dst, dst, MIPS_R_AT);
802 break;
803 }
804 emit_instr(ctx, ddivu, dst, MIPS_R_AT);
805 if (bpf_op == BPF_DIV)
806 emit_instr(ctx, mflo, dst);
807 else
808 emit_instr(ctx, mfhi, dst);
809 break;
810 case BPF_ALU64 | BPF_MOV | BPF_X: /* ALU64_REG */
811 case BPF_ALU64 | BPF_ADD | BPF_X: /* ALU64_REG */
812 case BPF_ALU64 | BPF_SUB | BPF_X: /* ALU64_REG */
813 case BPF_ALU64 | BPF_XOR | BPF_X: /* ALU64_REG */
814 case BPF_ALU64 | BPF_OR | BPF_X: /* ALU64_REG */
815 case BPF_ALU64 | BPF_AND | BPF_X: /* ALU64_REG */
816 case BPF_ALU64 | BPF_MUL | BPF_X: /* ALU64_REG */
817 case BPF_ALU64 | BPF_DIV | BPF_X: /* ALU64_REG */
818 case BPF_ALU64 | BPF_MOD | BPF_X: /* ALU64_REG */
819 case BPF_ALU64 | BPF_LSH | BPF_X: /* ALU64_REG */
820 case BPF_ALU64 | BPF_RSH | BPF_X: /* ALU64_REG */
821 case BPF_ALU64 | BPF_ARSH | BPF_X: /* ALU64_REG */
822 src = ebpf_to_mips_reg(ctx, insn, src_reg);
823 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
824 if (src < 0 || dst < 0)
825 return -EINVAL;
826 if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT)
827 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
828 did_move = false;
829 if (insn->src_reg == BPF_REG_10) {
830 if (bpf_op == BPF_MOV) {
831 emit_instr(ctx, daddiu, dst, MIPS_R_SP, MAX_BPF_STACK);
832 did_move = true;
833 } else {
834 emit_instr(ctx, daddiu, MIPS_R_AT, MIPS_R_SP, MAX_BPF_STACK);
835 src = MIPS_R_AT;
836 }
837 } else if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) {
838 int tmp_reg = MIPS_R_AT;
839
840 if (bpf_op == BPF_MOV) {
841 tmp_reg = dst;
842 did_move = true;
843 }
844 emit_instr(ctx, daddu, tmp_reg, src, MIPS_R_ZERO);
845 emit_instr(ctx, dinsu, tmp_reg, MIPS_R_ZERO, 32, 32);
846 src = MIPS_R_AT;
847 }
848 switch (bpf_op) {
849 case BPF_MOV:
850 if (!did_move)
851 emit_instr(ctx, daddu, dst, src, MIPS_R_ZERO);
852 break;
853 case BPF_ADD:
854 emit_instr(ctx, daddu, dst, dst, src);
855 break;
856 case BPF_SUB:
857 emit_instr(ctx, dsubu, dst, dst, src);
858 break;
859 case BPF_XOR:
860 emit_instr(ctx, xor, dst, dst, src);
861 break;
862 case BPF_OR:
863 emit_instr(ctx, or, dst, dst, src);
864 break;
865 case BPF_AND:
866 emit_instr(ctx, and, dst, dst, src);
867 break;
868 case BPF_MUL:
869 if (MIPS_ISA_REV >= 6) {
870 emit_instr(ctx, dmulu, dst, dst, src);
871 } else {
872 emit_instr(ctx, dmultu, dst, src);
873 emit_instr(ctx, mflo, dst);
874 }
875 break;
876 case BPF_DIV:
877 case BPF_MOD:
878 if (MIPS_ISA_REV >= 6) {
879 if (bpf_op == BPF_DIV)
880 emit_instr(ctx, ddivu_r6,
881 dst, dst, src);
882 else
883 emit_instr(ctx, modu, dst, dst, src);
884 break;
885 }
886 emit_instr(ctx, ddivu, dst, src);
887 if (bpf_op == BPF_DIV)
888 emit_instr(ctx, mflo, dst);
889 else
890 emit_instr(ctx, mfhi, dst);
891 break;
892 case BPF_LSH:
893 emit_instr(ctx, dsllv, dst, dst, src);
894 break;
895 case BPF_RSH:
896 emit_instr(ctx, dsrlv, dst, dst, src);
897 break;
898 case BPF_ARSH:
899 emit_instr(ctx, dsrav, dst, dst, src);
900 break;
901 default:
902 pr_err("ALU64_REG NOT HANDLED\n");
903 return -EINVAL;
904 }
905 break;
906 case BPF_ALU | BPF_MOV | BPF_X: /* ALU_REG */
907 case BPF_ALU | BPF_ADD | BPF_X: /* ALU_REG */
908 case BPF_ALU | BPF_SUB | BPF_X: /* ALU_REG */
909 case BPF_ALU | BPF_XOR | BPF_X: /* ALU_REG */
910 case BPF_ALU | BPF_OR | BPF_X: /* ALU_REG */
911 case BPF_ALU | BPF_AND | BPF_X: /* ALU_REG */
912 case BPF_ALU | BPF_MUL | BPF_X: /* ALU_REG */
913 case BPF_ALU | BPF_DIV | BPF_X: /* ALU_REG */
914 case BPF_ALU | BPF_MOD | BPF_X: /* ALU_REG */
915 case BPF_ALU | BPF_LSH | BPF_X: /* ALU_REG */
916 case BPF_ALU | BPF_RSH | BPF_X: /* ALU_REG */
917 case BPF_ALU | BPF_ARSH | BPF_X: /* ALU_REG */
918 src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp);
919 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
920 if (src < 0 || dst < 0)
921 return -EINVAL;
922 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
923 if (td == REG_64BIT) {
924 /* sign extend */
925 emit_instr(ctx, sll, dst, dst, 0);
926 }
927 did_move = false;
928 ts = get_reg_val_type(ctx, this_idx, insn->src_reg);
929 if (ts == REG_64BIT) {
930 int tmp_reg = MIPS_R_AT;
931
932 if (bpf_op == BPF_MOV) {
933 tmp_reg = dst;
934 did_move = true;
935 }
936 /* sign extend */
937 emit_instr(ctx, sll, tmp_reg, src, 0);
938 src = MIPS_R_AT;
939 }
940 switch (bpf_op) {
941 case BPF_MOV:
942 if (!did_move)
943 emit_instr(ctx, addu, dst, src, MIPS_R_ZERO);
944 break;
945 case BPF_ADD:
946 emit_instr(ctx, addu, dst, dst, src);
947 break;
948 case BPF_SUB:
949 emit_instr(ctx, subu, dst, dst, src);
950 break;
951 case BPF_XOR:
952 emit_instr(ctx, xor, dst, dst, src);
953 break;
954 case BPF_OR:
955 emit_instr(ctx, or, dst, dst, src);
956 break;
957 case BPF_AND:
958 emit_instr(ctx, and, dst, dst, src);
959 break;
960 case BPF_MUL:
961 emit_instr(ctx, mul, dst, dst, src);
962 break;
963 case BPF_DIV:
964 case BPF_MOD:
965 if (MIPS_ISA_REV >= 6) {
966 if (bpf_op == BPF_DIV)
967 emit_instr(ctx, divu_r6, dst, dst, src);
968 else
969 emit_instr(ctx, modu, dst, dst, src);
970 break;
971 }
972 emit_instr(ctx, divu, dst, src);
973 if (bpf_op == BPF_DIV)
974 emit_instr(ctx, mflo, dst);
975 else
976 emit_instr(ctx, mfhi, dst);
977 break;
978 case BPF_LSH:
979 emit_instr(ctx, sllv, dst, dst, src);
980 break;
981 case BPF_RSH:
982 emit_instr(ctx, srlv, dst, dst, src);
983 break;
984 case BPF_ARSH:
985 emit_instr(ctx, srav, dst, dst, src);
986 break;
987 default:
988 pr_err("ALU_REG NOT HANDLED\n");
989 return -EINVAL;
990 }
991 break;
992 case BPF_JMP | BPF_EXIT:
993 if (this_idx + 1 < exit_idx) {
994 b_off = b_imm(exit_idx, ctx);
995 if (is_bad_offset(b_off))
996 return -E2BIG;
997 emit_instr(ctx, beq, MIPS_R_ZERO, MIPS_R_ZERO, b_off);
998 emit_instr(ctx, nop);
999 }
1000 break;
1001 case BPF_JMP | BPF_JEQ | BPF_K: /* JMP_IMM */
1002 case BPF_JMP | BPF_JNE | BPF_K: /* JMP_IMM */
1003 cmp_eq = (bpf_op == BPF_JEQ);
1004 dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
1005 if (dst < 0)
1006 return dst;
1007 if (insn->imm == 0) {
1008 src = MIPS_R_ZERO;
1009 } else {
1010 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
1011 src = MIPS_R_AT;
1012 }
1013 goto jeq_common;
1014 case BPF_JMP | BPF_JEQ | BPF_X: /* JMP_REG */
1015 case BPF_JMP | BPF_JNE | BPF_X:
1016 case BPF_JMP | BPF_JSLT | BPF_X:
1017 case BPF_JMP | BPF_JSLE | BPF_X:
1018 case BPF_JMP | BPF_JSGT | BPF_X:
1019 case BPF_JMP | BPF_JSGE | BPF_X:
1020 case BPF_JMP | BPF_JLT | BPF_X:
1021 case BPF_JMP | BPF_JLE | BPF_X:
1022 case BPF_JMP | BPF_JGT | BPF_X:
1023 case BPF_JMP | BPF_JGE | BPF_X:
1024 case BPF_JMP | BPF_JSET | BPF_X:
1025 src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp);
1026 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1027 if (src < 0 || dst < 0)
1028 return -EINVAL;
1029 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
1030 ts = get_reg_val_type(ctx, this_idx, insn->src_reg);
1031 if (td == REG_32BIT && ts != REG_32BIT) {
1032 emit_instr(ctx, sll, MIPS_R_AT, src, 0);
1033 src = MIPS_R_AT;
1034 } else if (ts == REG_32BIT && td != REG_32BIT) {
1035 emit_instr(ctx, sll, MIPS_R_AT, dst, 0);
1036 dst = MIPS_R_AT;
1037 }
1038 if (bpf_op == BPF_JSET) {
1039 emit_instr(ctx, and, MIPS_R_AT, dst, src);
1040 cmp_eq = false;
1041 dst = MIPS_R_AT;
1042 src = MIPS_R_ZERO;
1043 } else if (bpf_op == BPF_JSGT || bpf_op == BPF_JSLE) {
1044 emit_instr(ctx, dsubu, MIPS_R_AT, dst, src);
1045 if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {
1046 b_off = b_imm(exit_idx, ctx);
1047 if (is_bad_offset(b_off))
1048 return -E2BIG;
1049 if (bpf_op == BPF_JSGT)
1050 emit_instr(ctx, blez, MIPS_R_AT, b_off);
1051 else
1052 emit_instr(ctx, bgtz, MIPS_R_AT, b_off);
1053 emit_instr(ctx, nop);
1054 return 2; /* We consumed the exit. */
1055 }
1056 b_off = b_imm(this_idx + insn->off + 1, ctx);
1057 if (is_bad_offset(b_off))
1058 return -E2BIG;
1059 if (bpf_op == BPF_JSGT)
1060 emit_instr(ctx, bgtz, MIPS_R_AT, b_off);
1061 else
1062 emit_instr(ctx, blez, MIPS_R_AT, b_off);
1063 emit_instr(ctx, nop);
1064 break;
1065 } else if (bpf_op == BPF_JSGE || bpf_op == BPF_JSLT) {
1066 emit_instr(ctx, slt, MIPS_R_AT, dst, src);
1067 cmp_eq = bpf_op == BPF_JSGE;
1068 dst = MIPS_R_AT;
1069 src = MIPS_R_ZERO;
1070 } else if (bpf_op == BPF_JGT || bpf_op == BPF_JLE) {
1071 /* dst or src could be AT */
1072 emit_instr(ctx, dsubu, MIPS_R_T8, dst, src);
1073 emit_instr(ctx, sltu, MIPS_R_AT, dst, src);
1074 /* SP known to be non-zero, movz becomes boolean not */
1075 if (MIPS_ISA_REV >= 6) {
1076 emit_instr(ctx, seleqz, MIPS_R_T9,
1077 MIPS_R_SP, MIPS_R_T8);
1078 } else {
1079 emit_instr(ctx, movz, MIPS_R_T9,
1080 MIPS_R_SP, MIPS_R_T8);
1081 emit_instr(ctx, movn, MIPS_R_T9,
1082 MIPS_R_ZERO, MIPS_R_T8);
1083 }
1084 emit_instr(ctx, or, MIPS_R_AT, MIPS_R_T9, MIPS_R_AT);
1085 cmp_eq = bpf_op == BPF_JGT;
1086 dst = MIPS_R_AT;
1087 src = MIPS_R_ZERO;
1088 } else if (bpf_op == BPF_JGE || bpf_op == BPF_JLT) {
1089 emit_instr(ctx, sltu, MIPS_R_AT, dst, src);
1090 cmp_eq = bpf_op == BPF_JGE;
1091 dst = MIPS_R_AT;
1092 src = MIPS_R_ZERO;
1093 } else { /* JNE/JEQ case */
1094 cmp_eq = (bpf_op == BPF_JEQ);
1095 }
1096jeq_common:
1097 /*
1098 * If the next insn is EXIT and we are jumping arround
1099 * only it, invert the sense of the compare and
1100 * conditionally jump to the exit. Poor man's branch
1101 * chaining.
1102 */
1103 if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {
1104 b_off = b_imm(exit_idx, ctx);
1105 if (is_bad_offset(b_off)) {
1106 target = j_target(ctx, exit_idx);
1107 if (target == (unsigned int)-1)
1108 return -E2BIG;
1109 cmp_eq = !cmp_eq;
1110 b_off = 4 * 3;
1111 if (!(ctx->offsets[this_idx] & OFFSETS_B_CONV)) {
1112 ctx->offsets[this_idx] |= OFFSETS_B_CONV;
1113 ctx->long_b_conversion = 1;
1114 }
1115 }
1116
1117 if (cmp_eq)
1118 emit_instr(ctx, bne, dst, src, b_off);
1119 else
1120 emit_instr(ctx, beq, dst, src, b_off);
1121 emit_instr(ctx, nop);
1122 if (ctx->offsets[this_idx] & OFFSETS_B_CONV) {
1123 emit_instr(ctx, j, target);
1124 emit_instr(ctx, nop);
1125 }
1126 return 2; /* We consumed the exit. */
1127 }
1128 b_off = b_imm(this_idx + insn->off + 1, ctx);
1129 if (is_bad_offset(b_off)) {
1130 target = j_target(ctx, this_idx + insn->off + 1);
1131 if (target == (unsigned int)-1)
1132 return -E2BIG;
1133 cmp_eq = !cmp_eq;
1134 b_off = 4 * 3;
1135 if (!(ctx->offsets[this_idx] & OFFSETS_B_CONV)) {
1136 ctx->offsets[this_idx] |= OFFSETS_B_CONV;
1137 ctx->long_b_conversion = 1;
1138 }
1139 }
1140
1141 if (cmp_eq)
1142 emit_instr(ctx, beq, dst, src, b_off);
1143 else
1144 emit_instr(ctx, bne, dst, src, b_off);
1145 emit_instr(ctx, nop);
1146 if (ctx->offsets[this_idx] & OFFSETS_B_CONV) {
1147 emit_instr(ctx, j, target);
1148 emit_instr(ctx, nop);
1149 }
1150 break;
1151 case BPF_JMP | BPF_JSGT | BPF_K: /* JMP_IMM */
1152 case BPF_JMP | BPF_JSGE | BPF_K: /* JMP_IMM */
1153 case BPF_JMP | BPF_JSLT | BPF_K: /* JMP_IMM */
1154 case BPF_JMP | BPF_JSLE | BPF_K: /* JMP_IMM */
1155 cmp_eq = (bpf_op == BPF_JSGE);
1156 dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
1157 if (dst < 0)
1158 return dst;
1159
1160 if (insn->imm == 0) {
1161 if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {
1162 b_off = b_imm(exit_idx, ctx);
1163 if (is_bad_offset(b_off))
1164 return -E2BIG;
1165 switch (bpf_op) {
1166 case BPF_JSGT:
1167 emit_instr(ctx, blez, dst, b_off);
1168 break;
1169 case BPF_JSGE:
1170 emit_instr(ctx, bltz, dst, b_off);
1171 break;
1172 case BPF_JSLT:
1173 emit_instr(ctx, bgez, dst, b_off);
1174 break;
1175 case BPF_JSLE:
1176 emit_instr(ctx, bgtz, dst, b_off);
1177 break;
1178 }
1179 emit_instr(ctx, nop);
1180 return 2; /* We consumed the exit. */
1181 }
1182 b_off = b_imm(this_idx + insn->off + 1, ctx);
1183 if (is_bad_offset(b_off))
1184 return -E2BIG;
1185 switch (bpf_op) {
1186 case BPF_JSGT:
1187 emit_instr(ctx, bgtz, dst, b_off);
1188 break;
1189 case BPF_JSGE:
1190 emit_instr(ctx, bgez, dst, b_off);
1191 break;
1192 case BPF_JSLT:
1193 emit_instr(ctx, bltz, dst, b_off);
1194 break;
1195 case BPF_JSLE:
1196 emit_instr(ctx, blez, dst, b_off);
1197 break;
1198 }
1199 emit_instr(ctx, nop);
1200 break;
1201 }
1202 /*
1203 * only "LT" compare available, so we must use imm + 1
1204 * to generate "GT" and imm -1 to generate LE
1205 */
1206 if (bpf_op == BPF_JSGT)
1207 t64s = insn->imm + 1;
1208 else if (bpf_op == BPF_JSLE)
1209 t64s = insn->imm + 1;
1210 else
1211 t64s = insn->imm;
1212
1213 cmp_eq = bpf_op == BPF_JSGT || bpf_op == BPF_JSGE;
1214 if (t64s >= S16_MIN && t64s <= S16_MAX) {
1215 emit_instr(ctx, slti, MIPS_R_AT, dst, (int)t64s);
1216 src = MIPS_R_AT;
1217 dst = MIPS_R_ZERO;
1218 goto jeq_common;
1219 }
1220 emit_const_to_reg(ctx, MIPS_R_AT, (u64)t64s);
1221 emit_instr(ctx, slt, MIPS_R_AT, dst, MIPS_R_AT);
1222 src = MIPS_R_AT;
1223 dst = MIPS_R_ZERO;
1224 goto jeq_common;
1225
1226 case BPF_JMP | BPF_JGT | BPF_K:
1227 case BPF_JMP | BPF_JGE | BPF_K:
1228 case BPF_JMP | BPF_JLT | BPF_K:
1229 case BPF_JMP | BPF_JLE | BPF_K:
1230 cmp_eq = (bpf_op == BPF_JGE);
1231 dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
1232 if (dst < 0)
1233 return dst;
1234 /*
1235 * only "LT" compare available, so we must use imm + 1
1236 * to generate "GT" and imm -1 to generate LE
1237 */
1238 if (bpf_op == BPF_JGT)
1239 t64s = (u64)(u32)(insn->imm) + 1;
1240 else if (bpf_op == BPF_JLE)
1241 t64s = (u64)(u32)(insn->imm) + 1;
1242 else
1243 t64s = (u64)(u32)(insn->imm);
1244
1245 cmp_eq = bpf_op == BPF_JGT || bpf_op == BPF_JGE;
1246
1247 emit_const_to_reg(ctx, MIPS_R_AT, (u64)t64s);
1248 emit_instr(ctx, sltu, MIPS_R_AT, dst, MIPS_R_AT);
1249 src = MIPS_R_AT;
1250 dst = MIPS_R_ZERO;
1251 goto jeq_common;
1252
1253 case BPF_JMP | BPF_JSET | BPF_K: /* JMP_IMM */
1254 dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
1255 if (dst < 0)
1256 return dst;
1257
1258 if (ctx->use_bbit_insns && hweight32((u32)insn->imm) == 1) {
1259 if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {
1260 b_off = b_imm(exit_idx, ctx);
1261 if (is_bad_offset(b_off))
1262 return -E2BIG;
1263 emit_instr(ctx, bbit0, dst, ffs((u32)insn->imm) - 1, b_off);
1264 emit_instr(ctx, nop);
1265 return 2; /* We consumed the exit. */
1266 }
1267 b_off = b_imm(this_idx + insn->off + 1, ctx);
1268 if (is_bad_offset(b_off))
1269 return -E2BIG;
1270 emit_instr(ctx, bbit1, dst, ffs((u32)insn->imm) - 1, b_off);
1271 emit_instr(ctx, nop);
1272 break;
1273 }
1274 t64 = (u32)insn->imm;
1275 emit_const_to_reg(ctx, MIPS_R_AT, t64);
1276 emit_instr(ctx, and, MIPS_R_AT, dst, MIPS_R_AT);
1277 src = MIPS_R_AT;
1278 dst = MIPS_R_ZERO;
1279 cmp_eq = false;
1280 goto jeq_common;
1281
1282 case BPF_JMP | BPF_JA:
1283 /*
1284 * Prefer relative branch for easier debugging, but
1285 * fall back if needed.
1286 */
1287 b_off = b_imm(this_idx + insn->off + 1, ctx);
1288 if (is_bad_offset(b_off)) {
1289 target = j_target(ctx, this_idx + insn->off + 1);
1290 if (target == (unsigned int)-1)
1291 return -E2BIG;
1292 emit_instr(ctx, j, target);
1293 } else {
1294 emit_instr(ctx, b, b_off);
1295 }
1296 emit_instr(ctx, nop);
1297 break;
1298 case BPF_LD | BPF_DW | BPF_IMM:
1299 if (insn->src_reg != 0)
1300 return -EINVAL;
1301 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1302 if (dst < 0)
1303 return dst;
1304 t64 = ((u64)(u32)insn->imm) | ((u64)(insn + 1)->imm << 32);
1305 emit_const_to_reg(ctx, dst, t64);
1306 return 2; /* Double slot insn */
1307
1308 case BPF_JMP | BPF_CALL:
1309 ctx->flags |= EBPF_SAVE_RA;
1310 t64s = (s64)insn->imm + (long)__bpf_call_base;
1311 emit_const_to_reg(ctx, MIPS_R_T9, (u64)t64s);
1312 emit_instr(ctx, jalr, MIPS_R_RA, MIPS_R_T9);
1313 /* delay slot */
1314 emit_instr(ctx, nop);
1315 break;
1316
1317 case BPF_JMP | BPF_TAIL_CALL:
1318 if (emit_bpf_tail_call(ctx, this_idx))
1319 return -EINVAL;
1320 break;
1321
1322 case BPF_ALU | BPF_END | BPF_FROM_BE:
1323 case BPF_ALU | BPF_END | BPF_FROM_LE:
1324 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1325 if (dst < 0)
1326 return dst;
1327 td = get_reg_val_type(ctx, this_idx, insn->dst_reg);
1328 if (insn->imm == 64 && td == REG_32BIT)
1329 emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
1330
1331 if (insn->imm != 64 && td == REG_64BIT) {
1332 /* sign extend */
1333 emit_instr(ctx, sll, dst, dst, 0);
1334 }
1335
1336#ifdef __BIG_ENDIAN
1337 need_swap = (BPF_SRC(insn->code) == BPF_FROM_LE);
1338#else
1339 need_swap = (BPF_SRC(insn->code) == BPF_FROM_BE);
1340#endif
1341 if (insn->imm == 16) {
1342 if (need_swap)
1343 emit_instr(ctx, wsbh, dst, dst);
1344 emit_instr(ctx, andi, dst, dst, 0xffff);
1345 } else if (insn->imm == 32) {
1346 if (need_swap) {
1347 emit_instr(ctx, wsbh, dst, dst);
1348 emit_instr(ctx, rotr, dst, dst, 16);
1349 }
1350 } else { /* 64-bit*/
1351 if (need_swap) {
1352 emit_instr(ctx, dsbh, dst, dst);
1353 emit_instr(ctx, dshd, dst, dst);
1354 }
1355 }
1356 break;
1357
1358 case BPF_ST | BPF_B | BPF_MEM:
1359 case BPF_ST | BPF_H | BPF_MEM:
1360 case BPF_ST | BPF_W | BPF_MEM:
1361 case BPF_ST | BPF_DW | BPF_MEM:
1362 if (insn->dst_reg == BPF_REG_10) {
1363 ctx->flags |= EBPF_SEEN_FP;
1364 dst = MIPS_R_SP;
1365 mem_off = insn->off + MAX_BPF_STACK;
1366 } else {
1367 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1368 if (dst < 0)
1369 return dst;
1370 mem_off = insn->off;
1371 }
1372 gen_imm_to_reg(insn, MIPS_R_AT, ctx);
1373 switch (BPF_SIZE(insn->code)) {
1374 case BPF_B:
1375 emit_instr(ctx, sb, MIPS_R_AT, mem_off, dst);
1376 break;
1377 case BPF_H:
1378 emit_instr(ctx, sh, MIPS_R_AT, mem_off, dst);
1379 break;
1380 case BPF_W:
1381 emit_instr(ctx, sw, MIPS_R_AT, mem_off, dst);
1382 break;
1383 case BPF_DW:
1384 emit_instr(ctx, sd, MIPS_R_AT, mem_off, dst);
1385 break;
1386 }
1387 break;
1388
1389 case BPF_LDX | BPF_B | BPF_MEM:
1390 case BPF_LDX | BPF_H | BPF_MEM:
1391 case BPF_LDX | BPF_W | BPF_MEM:
1392 case BPF_LDX | BPF_DW | BPF_MEM:
1393 if (insn->src_reg == BPF_REG_10) {
1394 ctx->flags |= EBPF_SEEN_FP;
1395 src = MIPS_R_SP;
1396 mem_off = insn->off + MAX_BPF_STACK;
1397 } else {
1398 src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp);
1399 if (src < 0)
1400 return src;
1401 mem_off = insn->off;
1402 }
1403 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1404 if (dst < 0)
1405 return dst;
1406 switch (BPF_SIZE(insn->code)) {
1407 case BPF_B:
1408 emit_instr(ctx, lbu, dst, mem_off, src);
1409 break;
1410 case BPF_H:
1411 emit_instr(ctx, lhu, dst, mem_off, src);
1412 break;
1413 case BPF_W:
1414 emit_instr(ctx, lw, dst, mem_off, src);
1415 break;
1416 case BPF_DW:
1417 emit_instr(ctx, ld, dst, mem_off, src);
1418 break;
1419 }
1420 break;
1421
1422 case BPF_STX | BPF_B | BPF_MEM:
1423 case BPF_STX | BPF_H | BPF_MEM:
1424 case BPF_STX | BPF_W | BPF_MEM:
1425 case BPF_STX | BPF_DW | BPF_MEM:
1426 case BPF_STX | BPF_W | BPF_XADD:
1427 case BPF_STX | BPF_DW | BPF_XADD:
1428 if (insn->dst_reg == BPF_REG_10) {
1429 ctx->flags |= EBPF_SEEN_FP;
1430 dst = MIPS_R_SP;
1431 mem_off = insn->off + MAX_BPF_STACK;
1432 } else {
1433 dst = ebpf_to_mips_reg(ctx, insn, dst_reg);
1434 if (dst < 0)
1435 return dst;
1436 mem_off = insn->off;
1437 }
1438 src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp);
1439 if (src < 0)
1440 return src;
1441 if (BPF_MODE(insn->code) == BPF_XADD) {
1442 /*
1443 * If mem_off does not fit within the 9 bit ll/sc
1444 * instruction immediate field, use a temp reg.
1445 */
1446 if (MIPS_ISA_REV >= 6 &&
1447 (mem_off >= BIT(8) || mem_off < -BIT(8))) {
1448 emit_instr(ctx, daddiu, MIPS_R_T6,
1449 dst, mem_off);
1450 mem_off = 0;
1451 dst = MIPS_R_T6;
1452 }
1453 switch (BPF_SIZE(insn->code)) {
1454 case BPF_W:
1455 if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) {
1456 emit_instr(ctx, sll, MIPS_R_AT, src, 0);
1457 src = MIPS_R_AT;
1458 }
1459 emit_instr(ctx, ll, MIPS_R_T8, mem_off, dst);
1460 emit_instr(ctx, addu, MIPS_R_T8, MIPS_R_T8, src);
1461 emit_instr(ctx, sc, MIPS_R_T8, mem_off, dst);
1462 /*
1463 * On failure back up to LL (-4
1464 * instructions of 4 bytes each
1465 */
1466 emit_instr(ctx, beq, MIPS_R_T8, MIPS_R_ZERO, -4 * 4);
1467 emit_instr(ctx, nop);
1468 break;
1469 case BPF_DW:
1470 if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) {
1471 emit_instr(ctx, daddu, MIPS_R_AT, src, MIPS_R_ZERO);
1472 emit_instr(ctx, dinsu, MIPS_R_AT, MIPS_R_ZERO, 32, 32);
1473 src = MIPS_R_AT;
1474 }
1475 emit_instr(ctx, lld, MIPS_R_T8, mem_off, dst);
1476 emit_instr(ctx, daddu, MIPS_R_T8, MIPS_R_T8, src);
1477 emit_instr(ctx, scd, MIPS_R_T8, mem_off, dst);
1478 emit_instr(ctx, beq, MIPS_R_T8, MIPS_R_ZERO, -4 * 4);
1479 emit_instr(ctx, nop);
1480 break;
1481 }
1482 } else { /* BPF_MEM */
1483 switch (BPF_SIZE(insn->code)) {
1484 case BPF_B:
1485 emit_instr(ctx, sb, src, mem_off, dst);
1486 break;
1487 case BPF_H:
1488 emit_instr(ctx, sh, src, mem_off, dst);
1489 break;
1490 case BPF_W:
1491 emit_instr(ctx, sw, src, mem_off, dst);
1492 break;
1493 case BPF_DW:
1494 if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) {
1495 emit_instr(ctx, daddu, MIPS_R_AT, src, MIPS_R_ZERO);
1496 emit_instr(ctx, dinsu, MIPS_R_AT, MIPS_R_ZERO, 32, 32);
1497 src = MIPS_R_AT;
1498 }
1499 emit_instr(ctx, sd, src, mem_off, dst);
1500 break;
1501 }
1502 }
1503 break;
1504
1505 default:
1506 pr_err("NOT HANDLED %d - (%02x)\n",
1507 this_idx, (unsigned int)insn->code);
1508 return -EINVAL;
1509 }
1510 return 1;
1511}
1512
1513#define RVT_VISITED_MASK 0xc000000000000000ull
1514#define RVT_FALL_THROUGH 0x4000000000000000ull
1515#define RVT_BRANCH_TAKEN 0x8000000000000000ull
1516#define RVT_DONE (RVT_FALL_THROUGH | RVT_BRANCH_TAKEN)
1517
1518static int build_int_body(struct jit_ctx *ctx)
1519{
1520 const struct bpf_prog *prog = ctx->skf;
1521 const struct bpf_insn *insn;
1522 int i, r;
1523
1524 for (i = 0; i < prog->len; ) {
1525 insn = prog->insnsi + i;
1526 if ((ctx->reg_val_types[i] & RVT_VISITED_MASK) == 0) {
1527 /* dead instruction, don't emit it. */
1528 i++;
1529 continue;
1530 }
1531
1532 if (ctx->target == NULL)
1533 ctx->offsets[i] = (ctx->offsets[i] & OFFSETS_B_CONV) | (ctx->idx * 4);
1534
1535 r = build_one_insn(insn, ctx, i, prog->len);
1536 if (r < 0)
1537 return r;
1538 i += r;
1539 }
1540 /* epilogue offset */
1541 if (ctx->target == NULL)
1542 ctx->offsets[i] = ctx->idx * 4;
1543
1544 /*
1545 * All exits have an offset of the epilogue, some offsets may
1546 * not have been set due to banch-around threading, so set
1547 * them now.
1548 */
1549 if (ctx->target == NULL)
1550 for (i = 0; i < prog->len; i++) {
1551 insn = prog->insnsi + i;
1552 if (insn->code == (BPF_JMP | BPF_EXIT))
1553 ctx->offsets[i] = ctx->idx * 4;
1554 }
1555 return 0;
1556}
1557
1558/* return the last idx processed, or negative for error */
1559static int reg_val_propagate_range(struct jit_ctx *ctx, u64 initial_rvt,
1560 int start_idx, bool follow_taken)
1561{
1562 const struct bpf_prog *prog = ctx->skf;
1563 const struct bpf_insn *insn;
1564 u64 exit_rvt = initial_rvt;
1565 u64 *rvt = ctx->reg_val_types;
1566 int idx;
1567 int reg;
1568
1569 for (idx = start_idx; idx < prog->len; idx++) {
1570 rvt[idx] = (rvt[idx] & RVT_VISITED_MASK) | exit_rvt;
1571 insn = prog->insnsi + idx;
1572 switch (BPF_CLASS(insn->code)) {
1573 case BPF_ALU:
1574 switch (BPF_OP(insn->code)) {
1575 case BPF_ADD:
1576 case BPF_SUB:
1577 case BPF_MUL:
1578 case BPF_DIV:
1579 case BPF_OR:
1580 case BPF_AND:
1581 case BPF_LSH:
1582 case BPF_RSH:
1583 case BPF_NEG:
1584 case BPF_MOD:
1585 case BPF_XOR:
1586 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1587 break;
1588 case BPF_MOV:
1589 if (BPF_SRC(insn->code)) {
1590 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1591 } else {
1592 /* IMM to REG move*/
1593 if (insn->imm >= 0)
1594 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1595 else
1596 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1597 }
1598 break;
1599 case BPF_END:
1600 if (insn->imm == 64)
1601 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1602 else if (insn->imm == 32)
1603 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1604 else /* insn->imm == 16 */
1605 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1606 break;
1607 }
1608 rvt[idx] |= RVT_DONE;
1609 break;
1610 case BPF_ALU64:
1611 switch (BPF_OP(insn->code)) {
1612 case BPF_MOV:
1613 if (BPF_SRC(insn->code)) {
1614 /* REG to REG move*/
1615 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1616 } else {
1617 /* IMM to REG move*/
1618 if (insn->imm >= 0)
1619 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1620 else
1621 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT_32BIT);
1622 }
1623 break;
1624 default:
1625 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1626 }
1627 rvt[idx] |= RVT_DONE;
1628 break;
1629 case BPF_LD:
1630 switch (BPF_SIZE(insn->code)) {
1631 case BPF_DW:
1632 if (BPF_MODE(insn->code) == BPF_IMM) {
1633 s64 val;
1634
1635 val = (s64)((u32)insn->imm | ((u64)(insn + 1)->imm << 32));
1636 if (val > 0 && val <= S32_MAX)
1637 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1638 else if (val >= S32_MIN && val <= S32_MAX)
1639 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT_32BIT);
1640 else
1641 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1642 rvt[idx] |= RVT_DONE;
1643 idx++;
1644 } else {
1645 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1646 }
1647 break;
1648 case BPF_B:
1649 case BPF_H:
1650 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1651 break;
1652 case BPF_W:
1653 if (BPF_MODE(insn->code) == BPF_IMM)
1654 set_reg_val_type(&exit_rvt, insn->dst_reg,
1655 insn->imm >= 0 ? REG_32BIT_POS : REG_32BIT);
1656 else
1657 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1658 break;
1659 }
1660 rvt[idx] |= RVT_DONE;
1661 break;
1662 case BPF_LDX:
1663 switch (BPF_SIZE(insn->code)) {
1664 case BPF_DW:
1665 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT);
1666 break;
1667 case BPF_B:
1668 case BPF_H:
1669 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS);
1670 break;
1671 case BPF_W:
1672 set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT);
1673 break;
1674 }
1675 rvt[idx] |= RVT_DONE;
1676 break;
1677 case BPF_JMP:
1678 switch (BPF_OP(insn->code)) {
1679 case BPF_EXIT:
1680 rvt[idx] = RVT_DONE | exit_rvt;
1681 rvt[prog->len] = exit_rvt;
1682 return idx;
1683 case BPF_JA:
1684 rvt[idx] |= RVT_DONE;
1685 idx += insn->off;
1686 break;
1687 case BPF_JEQ:
1688 case BPF_JGT:
1689 case BPF_JGE:
1690 case BPF_JLT:
1691 case BPF_JLE:
1692 case BPF_JSET:
1693 case BPF_JNE:
1694 case BPF_JSGT:
1695 case BPF_JSGE:
1696 case BPF_JSLT:
1697 case BPF_JSLE:
1698 if (follow_taken) {
1699 rvt[idx] |= RVT_BRANCH_TAKEN;
1700 idx += insn->off;
1701 follow_taken = false;
1702 } else {
1703 rvt[idx] |= RVT_FALL_THROUGH;
1704 }
1705 break;
1706 case BPF_CALL:
1707 set_reg_val_type(&exit_rvt, BPF_REG_0, REG_64BIT);
1708 /* Upon call return, argument registers are clobbered. */
1709 for (reg = BPF_REG_0; reg <= BPF_REG_5; reg++)
1710 set_reg_val_type(&exit_rvt, reg, REG_64BIT);
1711
1712 rvt[idx] |= RVT_DONE;
1713 break;
1714 default:
1715 WARN(1, "Unhandled BPF_JMP case.\n");
1716 rvt[idx] |= RVT_DONE;
1717 break;
1718 }
1719 break;
1720 default:
1721 rvt[idx] |= RVT_DONE;
1722 break;
1723 }
1724 }
1725 return idx;
1726}
1727
1728/*
1729 * Track the value range (i.e. 32-bit vs. 64-bit) of each register at
1730 * each eBPF insn. This allows unneeded sign and zero extension
1731 * operations to be omitted.
1732 *
1733 * Doesn't handle yet confluence of control paths with conflicting
1734 * ranges, but it is good enough for most sane code.
1735 */
1736static int reg_val_propagate(struct jit_ctx *ctx)
1737{
1738 const struct bpf_prog *prog = ctx->skf;
1739 u64 exit_rvt;
1740 int reg;
1741 int i;
1742
1743 /*
1744 * 11 registers * 3 bits/reg leaves top bits free for other
1745 * uses. Bit-62..63 used to see if we have visited an insn.
1746 */
1747 exit_rvt = 0;
1748
1749 /* Upon entry, argument registers are 64-bit. */
1750 for (reg = BPF_REG_1; reg <= BPF_REG_5; reg++)
1751 set_reg_val_type(&exit_rvt, reg, REG_64BIT);
1752
1753 /*
1754 * First follow all conditional branches on the fall-through
1755 * edge of control flow..
1756 */
1757 reg_val_propagate_range(ctx, exit_rvt, 0, false);
1758restart_search:
1759 /*
1760 * Then repeatedly find the first conditional branch where
1761 * both edges of control flow have not been taken, and follow
1762 * the branch taken edge. We will end up restarting the
1763 * search once per conditional branch insn.
1764 */
1765 for (i = 0; i < prog->len; i++) {
1766 u64 rvt = ctx->reg_val_types[i];
1767
1768 if ((rvt & RVT_VISITED_MASK) == RVT_DONE ||
1769 (rvt & RVT_VISITED_MASK) == 0)
1770 continue;
1771 if ((rvt & RVT_VISITED_MASK) == RVT_FALL_THROUGH) {
1772 reg_val_propagate_range(ctx, rvt & ~RVT_VISITED_MASK, i, true);
1773 } else { /* RVT_BRANCH_TAKEN */
1774 WARN(1, "Unexpected RVT_BRANCH_TAKEN case.\n");
1775 reg_val_propagate_range(ctx, rvt & ~RVT_VISITED_MASK, i, false);
1776 }
1777 goto restart_search;
1778 }
1779 /*
1780 * Eventually all conditional branches have been followed on
1781 * both branches and we are done. Any insn that has not been
1782 * visited at this point is dead.
1783 */
1784
1785 return 0;
1786}
1787
1788static void jit_fill_hole(void *area, unsigned int size)
1789{
1790 u32 *p;
1791
1792 /* We are guaranteed to have aligned memory. */
1793 for (p = area; size >= sizeof(u32); size -= sizeof(u32))
1794 uasm_i_break(&p, BRK_BUG); /* Increments p */
1795}
1796
1797struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
1798{
1799 struct bpf_prog *orig_prog = prog;
1800 bool tmp_blinded = false;
1801 struct bpf_prog *tmp;
1802 struct bpf_binary_header *header = NULL;
1803 struct jit_ctx ctx;
1804 unsigned int image_size;
1805 u8 *image_ptr;
1806
1807 if (!prog->jit_requested)
1808 return prog;
1809
1810 tmp = bpf_jit_blind_constants(prog);
1811 /* If blinding was requested and we failed during blinding,
1812 * we must fall back to the interpreter.
1813 */
1814 if (IS_ERR(tmp))
1815 return orig_prog;
1816 if (tmp != prog) {
1817 tmp_blinded = true;
1818 prog = tmp;
1819 }
1820
1821 memset(&ctx, 0, sizeof(ctx));
1822
1823 preempt_disable();
1824 switch (current_cpu_type()) {
1825 case CPU_CAVIUM_OCTEON:
1826 case CPU_CAVIUM_OCTEON_PLUS:
1827 case CPU_CAVIUM_OCTEON2:
1828 case CPU_CAVIUM_OCTEON3:
1829 ctx.use_bbit_insns = 1;
1830 break;
1831 default:
1832 ctx.use_bbit_insns = 0;
1833 }
1834 preempt_enable();
1835
1836 ctx.offsets = kcalloc(prog->len + 1, sizeof(*ctx.offsets), GFP_KERNEL);
1837 if (ctx.offsets == NULL)
1838 goto out_err;
1839
1840 ctx.reg_val_types = kcalloc(prog->len + 1, sizeof(*ctx.reg_val_types), GFP_KERNEL);
1841 if (ctx.reg_val_types == NULL)
1842 goto out_err;
1843
1844 ctx.skf = prog;
1845
1846 if (reg_val_propagate(&ctx))
1847 goto out_err;
1848
1849 /*
1850 * First pass discovers used resources and instruction offsets
1851 * assuming short branches are used.
1852 */
1853 if (build_int_body(&ctx))
1854 goto out_err;
1855
1856 /*
1857 * If no calls are made (EBPF_SAVE_RA), then tail call count
1858 * in $v1, else we must save in n$s4.
1859 */
1860 if (ctx.flags & EBPF_SEEN_TC) {
1861 if (ctx.flags & EBPF_SAVE_RA)
1862 ctx.flags |= EBPF_SAVE_S4;
1863 else
1864 ctx.flags |= EBPF_TCC_IN_V1;
1865 }
1866
1867 /*
1868 * Second pass generates offsets, if any branches are out of
1869 * range a jump-around long sequence is generated, and we have
1870 * to try again from the beginning to generate the new
1871 * offsets. This is done until no additional conversions are
1872 * necessary.
1873 */
1874 do {
1875 ctx.idx = 0;
1876 ctx.gen_b_offsets = 1;
1877 ctx.long_b_conversion = 0;
1878 if (gen_int_prologue(&ctx))
1879 goto out_err;
1880 if (build_int_body(&ctx))
1881 goto out_err;
1882 if (build_int_epilogue(&ctx, MIPS_R_RA))
1883 goto out_err;
1884 } while (ctx.long_b_conversion);
1885
1886 image_size = 4 * ctx.idx;
1887
1888 header = bpf_jit_binary_alloc(image_size, &image_ptr,
1889 sizeof(u32), jit_fill_hole);
1890 if (header == NULL)
1891 goto out_err;
1892
1893 ctx.target = (u32 *)image_ptr;
1894
1895 /* Third pass generates the code */
1896 ctx.idx = 0;
1897 if (gen_int_prologue(&ctx))
1898 goto out_err;
1899 if (build_int_body(&ctx))
1900 goto out_err;
1901 if (build_int_epilogue(&ctx, MIPS_R_RA))
1902 goto out_err;
1903
1904 /* Update the icache */
1905 flush_icache_range((unsigned long)ctx.target,
1906 (unsigned long)&ctx.target[ctx.idx]);
1907
1908 if (bpf_jit_enable > 1)
1909 /* Dump JIT code */
1910 bpf_jit_dump(prog->len, image_size, 2, ctx.target);
1911
1912 bpf_jit_binary_lock_ro(header);
1913 prog->bpf_func = (void *)ctx.target;
1914 prog->jited = 1;
1915 prog->jited_len = image_size;
1916out_normal:
1917 if (tmp_blinded)
1918 bpf_jit_prog_release_other(prog, prog == orig_prog ?
1919 tmp : orig_prog);
1920 kfree(ctx.offsets);
1921 kfree(ctx.reg_val_types);
1922
1923 return prog;
1924
1925out_err:
1926 prog = orig_prog;
1927 if (header)
1928 bpf_jit_binary_free(header);
1929 goto out_normal;
1930}