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Markos Chandrasc6610de2014-04-08 12:47:14 +01001/*
2 * Just-In-Time compiler for BPF filters on MIPS
3 *
4 * Copyright (c) 2014 Imagination Technologies Ltd.
5 * Author: Markos Chandras <markos.chandras@imgtec.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; version 2 of the License.
10 */
11
12#include <linux/bitops.h>
13#include <linux/compiler.h>
14#include <linux/errno.h>
15#include <linux/filter.h>
16#include <linux/if_vlan.h>
17#include <linux/kconfig.h>
18#include <linux/moduleloader.h>
19#include <linux/netdevice.h>
20#include <linux/string.h>
21#include <linux/slab.h>
22#include <linux/types.h>
23#include <asm/bitops.h>
24#include <asm/cacheflush.h>
25#include <asm/cpu-features.h>
26#include <asm/uasm.h>
27
28#include "bpf_jit.h"
29
30/* ABI
31 *
32 * s0 1st scratch register
33 * s1 2nd scratch register
34 * s2 offset register
35 * s3 BPF register A
36 * s4 BPF register X
37 * s5 *skb
38 * s6 *scratch memory
39 *
40 * On entry (*bpf_func)(*skb, *filter)
41 * a0 = MIPS_R_A0 = skb;
42 * a1 = MIPS_R_A1 = filter;
43 *
44 * Stack
45 * ...
46 * M[15]
47 * M[14]
48 * M[13]
49 * ...
50 * M[0] <-- r_M
51 * saved reg k-1
52 * saved reg k-2
53 * ...
54 * saved reg 0 <-- r_sp
55 * <no argument area>
56 *
57 * Packet layout
58 *
59 * <--------------------- len ------------------------>
60 * <--skb-len(r_skb_hl)-->< ----- skb->data_len ------>
61 * ----------------------------------------------------
62 * | skb->data |
63 * ----------------------------------------------------
64 */
65
66#define RSIZE (sizeof(unsigned long))
67#define ptr typeof(unsigned long)
68
69/* ABI specific return values */
70#ifdef CONFIG_32BIT /* O32 */
71#ifdef CONFIG_CPU_LITTLE_ENDIAN
72#define r_err MIPS_R_V1
73#define r_val MIPS_R_V0
74#else /* CONFIG_CPU_LITTLE_ENDIAN */
75#define r_err MIPS_R_V0
76#define r_val MIPS_R_V1
77#endif
78#else /* N64 */
79#define r_err MIPS_R_V0
80#define r_val MIPS_R_V0
81#endif
82
83#define r_ret MIPS_R_V0
84
85/*
86 * Use 2 scratch registers to avoid pipeline interlocks.
87 * There is no overhead during epilogue and prologue since
88 * any of the $s0-$s6 registers will only be preserved if
89 * they are going to actually be used.
90 */
91#define r_s0 MIPS_R_S0 /* scratch reg 1 */
92#define r_s1 MIPS_R_S1 /* scratch reg 2 */
93#define r_off MIPS_R_S2
94#define r_A MIPS_R_S3
95#define r_X MIPS_R_S4
96#define r_skb MIPS_R_S5
97#define r_M MIPS_R_S6
98#define r_tmp_imm MIPS_R_T6 /* No need to preserve this */
99#define r_tmp MIPS_R_T7 /* No need to preserve this */
100#define r_zero MIPS_R_ZERO
101#define r_sp MIPS_R_SP
102#define r_ra MIPS_R_RA
103
104#define SCRATCH_OFF(k) (4 * (k))
105
106/* JIT flags */
107#define SEEN_CALL (1 << BPF_MEMWORDS)
108#define SEEN_SREG_SFT (BPF_MEMWORDS + 1)
109#define SEEN_SREG_BASE (1 << SEEN_SREG_SFT)
110#define SEEN_SREG(x) (SEEN_SREG_BASE << (x))
111#define SEEN_S0 SEEN_SREG(0)
112#define SEEN_S1 SEEN_SREG(1)
113#define SEEN_OFF SEEN_SREG(2)
114#define SEEN_A SEEN_SREG(3)
115#define SEEN_X SEEN_SREG(4)
116#define SEEN_SKB SEEN_SREG(5)
117#define SEEN_MEM SEEN_SREG(6)
118
119/* Arguments used by JIT */
120#define ARGS_USED_BY_JIT 2 /* only applicable to 64-bit */
121
Markos Chandrasc6610de2014-04-08 12:47:14 +0100122#define SBIT(x) (1 << (x)) /* Signed version of BIT() */
123
124/**
125 * struct jit_ctx - JIT context
126 * @skf: The sk_filter
127 * @prologue_bytes: Number of bytes for prologue
128 * @idx: Instruction index
129 * @flags: JIT flags
130 * @offsets: Instruction offsets
131 * @target: Memory location for the compiled filter
132 */
133struct jit_ctx {
134 const struct sk_filter *skf;
135 unsigned int prologue_bytes;
136 u32 idx;
137 u32 flags;
138 u32 *offsets;
139 u32 *target;
140};
141
142
143static inline int optimize_div(u32 *k)
144{
145 /* power of 2 divides can be implemented with right shift */
146 if (!(*k & (*k-1))) {
147 *k = ilog2(*k);
148 return 1;
149 }
150
151 return 0;
152}
153
Markos Chandras95782bf2014-06-25 09:37:21 +0100154static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx);
155
Markos Chandrasc6610de2014-04-08 12:47:14 +0100156/* Simply emit the instruction if the JIT memory space has been allocated */
157#define emit_instr(ctx, func, ...) \
158do { \
159 if ((ctx)->target != NULL) { \
160 u32 *p = &(ctx)->target[ctx->idx]; \
161 uasm_i_##func(&p, ##__VA_ARGS__); \
162 } \
163 (ctx)->idx++; \
164} while (0)
165
166/* Determine if immediate is within the 16-bit signed range */
167static inline bool is_range16(s32 imm)
168{
Markos Chandras10c4d612014-06-23 10:38:55 +0100169 return !(imm >= SBIT(15) || imm < -SBIT(15));
Markos Chandrasc6610de2014-04-08 12:47:14 +0100170}
171
172static inline void emit_addu(unsigned int dst, unsigned int src1,
173 unsigned int src2, struct jit_ctx *ctx)
174{
175 emit_instr(ctx, addu, dst, src1, src2);
176}
177
178static inline void emit_nop(struct jit_ctx *ctx)
179{
180 emit_instr(ctx, nop);
181}
182
183/* Load a u32 immediate to a register */
184static inline void emit_load_imm(unsigned int dst, u32 imm, struct jit_ctx *ctx)
185{
186 if (ctx->target != NULL) {
187 /* addiu can only handle s16 */
Markos Chandras10c4d612014-06-23 10:38:55 +0100188 if (!is_range16(imm)) {
Markos Chandrasc6610de2014-04-08 12:47:14 +0100189 u32 *p = &ctx->target[ctx->idx];
190 uasm_i_lui(&p, r_tmp_imm, (s32)imm >> 16);
191 p = &ctx->target[ctx->idx + 1];
192 uasm_i_ori(&p, dst, r_tmp_imm, imm & 0xffff);
193 } else {
194 u32 *p = &ctx->target[ctx->idx];
195 uasm_i_addiu(&p, dst, r_zero, imm);
196 }
197 }
198 ctx->idx++;
199
Markos Chandras10c4d612014-06-23 10:38:55 +0100200 if (!is_range16(imm))
Markos Chandrasc6610de2014-04-08 12:47:14 +0100201 ctx->idx++;
202}
203
204static inline void emit_or(unsigned int dst, unsigned int src1,
205 unsigned int src2, struct jit_ctx *ctx)
206{
207 emit_instr(ctx, or, dst, src1, src2);
208}
209
210static inline void emit_ori(unsigned int dst, unsigned src, u32 imm,
211 struct jit_ctx *ctx)
212{
213 if (imm >= BIT(16)) {
214 emit_load_imm(r_tmp, imm, ctx);
215 emit_or(dst, src, r_tmp, ctx);
216 } else {
217 emit_instr(ctx, ori, dst, src, imm);
218 }
219}
220
221
222static inline void emit_daddu(unsigned int dst, unsigned int src1,
223 unsigned int src2, struct jit_ctx *ctx)
224{
225 emit_instr(ctx, daddu, dst, src1, src2);
226}
227
228static inline void emit_daddiu(unsigned int dst, unsigned int src,
229 int imm, struct jit_ctx *ctx)
230{
231 /*
232 * Only used for stack, so the imm is relatively small
233 * and it fits in 15-bits
234 */
235 emit_instr(ctx, daddiu, dst, src, imm);
236}
237
238static inline void emit_addiu(unsigned int dst, unsigned int src,
239 u32 imm, struct jit_ctx *ctx)
240{
Markos Chandras10c4d612014-06-23 10:38:55 +0100241 if (!is_range16(imm)) {
Markos Chandrasc6610de2014-04-08 12:47:14 +0100242 emit_load_imm(r_tmp, imm, ctx);
243 emit_addu(dst, r_tmp, src, ctx);
244 } else {
245 emit_instr(ctx, addiu, dst, src, imm);
246 }
247}
248
249static inline void emit_and(unsigned int dst, unsigned int src1,
250 unsigned int src2, struct jit_ctx *ctx)
251{
252 emit_instr(ctx, and, dst, src1, src2);
253}
254
255static inline void emit_andi(unsigned int dst, unsigned int src,
256 u32 imm, struct jit_ctx *ctx)
257{
258 /* If imm does not fit in u16 then load it to register */
259 if (imm >= BIT(16)) {
260 emit_load_imm(r_tmp, imm, ctx);
261 emit_and(dst, src, r_tmp, ctx);
262 } else {
263 emit_instr(ctx, andi, dst, src, imm);
264 }
265}
266
267static inline void emit_xor(unsigned int dst, unsigned int src1,
268 unsigned int src2, struct jit_ctx *ctx)
269{
270 emit_instr(ctx, xor, dst, src1, src2);
271}
272
273static inline void emit_xori(ptr dst, ptr src, u32 imm, struct jit_ctx *ctx)
274{
275 /* If imm does not fit in u16 then load it to register */
276 if (imm >= BIT(16)) {
277 emit_load_imm(r_tmp, imm, ctx);
278 emit_xor(dst, src, r_tmp, ctx);
279 } else {
280 emit_instr(ctx, xori, dst, src, imm);
281 }
282}
283
284static inline void emit_stack_offset(int offset, struct jit_ctx *ctx)
285{
286 if (config_enabled(CONFIG_64BIT))
287 emit_instr(ctx, daddiu, r_sp, r_sp, offset);
288 else
289 emit_instr(ctx, addiu, r_sp, r_sp, offset);
290
291}
292
293static inline void emit_subu(unsigned int dst, unsigned int src1,
294 unsigned int src2, struct jit_ctx *ctx)
295{
296 emit_instr(ctx, subu, dst, src1, src2);
297}
298
299static inline void emit_neg(unsigned int reg, struct jit_ctx *ctx)
300{
301 emit_subu(reg, r_zero, reg, ctx);
302}
303
304static inline void emit_sllv(unsigned int dst, unsigned int src,
305 unsigned int sa, struct jit_ctx *ctx)
306{
307 emit_instr(ctx, sllv, dst, src, sa);
308}
309
310static inline void emit_sll(unsigned int dst, unsigned int src,
311 unsigned int sa, struct jit_ctx *ctx)
312{
313 /* sa is 5-bits long */
Markos Chandras95782bf2014-06-25 09:37:21 +0100314 if (sa >= BIT(5))
315 /* Shifting >= 32 results in zero */
316 emit_jit_reg_move(dst, r_zero, ctx);
317 else
318 emit_instr(ctx, sll, dst, src, sa);
Markos Chandrasc6610de2014-04-08 12:47:14 +0100319}
320
321static inline void emit_srlv(unsigned int dst, unsigned int src,
322 unsigned int sa, struct jit_ctx *ctx)
323{
324 emit_instr(ctx, srlv, dst, src, sa);
325}
326
327static inline void emit_srl(unsigned int dst, unsigned int src,
328 unsigned int sa, struct jit_ctx *ctx)
329{
330 /* sa is 5-bits long */
Markos Chandras95782bf2014-06-25 09:37:21 +0100331 if (sa >= BIT(5))
332 /* Shifting >= 32 results in zero */
333 emit_jit_reg_move(dst, r_zero, ctx);
334 else
335 emit_instr(ctx, srl, dst, src, sa);
Markos Chandrasc6610de2014-04-08 12:47:14 +0100336}
337
Markos Chandras55393ee2014-06-23 10:38:48 +0100338static inline void emit_slt(unsigned int dst, unsigned int src1,
339 unsigned int src2, struct jit_ctx *ctx)
340{
341 emit_instr(ctx, slt, dst, src1, src2);
342}
343
Markos Chandrasc6610de2014-04-08 12:47:14 +0100344static inline void emit_sltu(unsigned int dst, unsigned int src1,
345 unsigned int src2, struct jit_ctx *ctx)
346{
347 emit_instr(ctx, sltu, dst, src1, src2);
348}
349
350static inline void emit_sltiu(unsigned dst, unsigned int src,
351 unsigned int imm, struct jit_ctx *ctx)
352{
353 /* 16 bit immediate */
Markos Chandras10c4d612014-06-23 10:38:55 +0100354 if (!is_range16((s32)imm)) {
Markos Chandrasc6610de2014-04-08 12:47:14 +0100355 emit_load_imm(r_tmp, imm, ctx);
356 emit_sltu(dst, src, r_tmp, ctx);
357 } else {
358 emit_instr(ctx, sltiu, dst, src, imm);
359 }
360
361}
362
363/* Store register on the stack */
364static inline void emit_store_stack_reg(ptr reg, ptr base,
365 unsigned int offset,
366 struct jit_ctx *ctx)
367{
368 if (config_enabled(CONFIG_64BIT))
369 emit_instr(ctx, sd, reg, offset, base);
370 else
371 emit_instr(ctx, sw, reg, offset, base);
372}
373
374static inline void emit_store(ptr reg, ptr base, unsigned int offset,
375 struct jit_ctx *ctx)
376{
377 emit_instr(ctx, sw, reg, offset, base);
378}
379
380static inline void emit_load_stack_reg(ptr reg, ptr base,
381 unsigned int offset,
382 struct jit_ctx *ctx)
383{
384 if (config_enabled(CONFIG_64BIT))
385 emit_instr(ctx, ld, reg, offset, base);
386 else
387 emit_instr(ctx, lw, reg, offset, base);
388}
389
390static inline void emit_load(unsigned int reg, unsigned int base,
391 unsigned int offset, struct jit_ctx *ctx)
392{
393 emit_instr(ctx, lw, reg, offset, base);
394}
395
396static inline void emit_load_byte(unsigned int reg, unsigned int base,
397 unsigned int offset, struct jit_ctx *ctx)
398{
399 emit_instr(ctx, lb, reg, offset, base);
400}
401
402static inline void emit_half_load(unsigned int reg, unsigned int base,
403 unsigned int offset, struct jit_ctx *ctx)
404{
405 emit_instr(ctx, lh, reg, offset, base);
406}
407
408static inline void emit_mul(unsigned int dst, unsigned int src1,
409 unsigned int src2, struct jit_ctx *ctx)
410{
411 emit_instr(ctx, mul, dst, src1, src2);
412}
413
414static inline void emit_div(unsigned int dst, unsigned int src,
415 struct jit_ctx *ctx)
416{
417 if (ctx->target != NULL) {
418 u32 *p = &ctx->target[ctx->idx];
419 uasm_i_divu(&p, dst, src);
420 p = &ctx->target[ctx->idx + 1];
Markos Chandras35a8e162014-06-23 10:38:47 +0100421 uasm_i_mflo(&p, dst);
Markos Chandrasc6610de2014-04-08 12:47:14 +0100422 }
423 ctx->idx += 2; /* 2 insts */
424}
425
426static inline void emit_mod(unsigned int dst, unsigned int src,
427 struct jit_ctx *ctx)
428{
429 if (ctx->target != NULL) {
430 u32 *p = &ctx->target[ctx->idx];
431 uasm_i_divu(&p, dst, src);
432 p = &ctx->target[ctx->idx + 1];
433 uasm_i_mflo(&p, dst);
434 }
435 ctx->idx += 2; /* 2 insts */
436}
437
438static inline void emit_dsll(unsigned int dst, unsigned int src,
439 unsigned int sa, struct jit_ctx *ctx)
440{
441 emit_instr(ctx, dsll, dst, src, sa);
442}
443
444static inline void emit_dsrl32(unsigned int dst, unsigned int src,
445 unsigned int sa, struct jit_ctx *ctx)
446{
447 emit_instr(ctx, dsrl32, dst, src, sa);
448}
449
450static inline void emit_wsbh(unsigned int dst, unsigned int src,
451 struct jit_ctx *ctx)
452{
453 emit_instr(ctx, wsbh, dst, src);
454}
455
456/* load a function pointer to register */
457static inline void emit_load_func(unsigned int reg, ptr imm,
458 struct jit_ctx *ctx)
459{
460 if (config_enabled(CONFIG_64BIT)) {
461 /* At this point imm is always 64-bit */
462 emit_load_imm(r_tmp, (u64)imm >> 32, ctx);
463 emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */
464 emit_ori(r_tmp, r_tmp_imm, (imm >> 16) & 0xffff, ctx);
465 emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */
466 emit_ori(reg, r_tmp_imm, imm & 0xffff, ctx);
467 } else {
468 emit_load_imm(reg, imm, ctx);
469 }
470}
471
472/* Move to real MIPS register */
473static inline void emit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx)
474{
475 if (config_enabled(CONFIG_64BIT))
476 emit_daddu(dst, src, r_zero, ctx);
477 else
478 emit_addu(dst, src, r_zero, ctx);
479}
480
481/* Move to JIT (32-bit) register */
482static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx)
483{
484 emit_addu(dst, src, r_zero, ctx);
485}
486
487/* Compute the immediate value for PC-relative branches. */
488static inline u32 b_imm(unsigned int tgt, struct jit_ctx *ctx)
489{
490 if (ctx->target == NULL)
491 return 0;
492
493 /*
494 * We want a pc-relative branch. We only do forward branches
495 * so tgt is always after pc. tgt is the instruction offset
496 * we want to jump to.
497
498 * Branch on MIPS:
499 * I: target_offset <- sign_extend(offset)
500 * I+1: PC += target_offset (delay slot)
501 *
502 * ctx->idx currently points to the branch instruction
503 * but the offset is added to the delay slot so we need
504 * to subtract 4.
505 */
506 return ctx->offsets[tgt] -
507 (ctx->idx * 4 - ctx->prologue_bytes) - 4;
508}
509
510static inline void emit_bcond(int cond, unsigned int reg1, unsigned int reg2,
511 unsigned int imm, struct jit_ctx *ctx)
512{
513 if (ctx->target != NULL) {
514 u32 *p = &ctx->target[ctx->idx];
515
516 switch (cond) {
517 case MIPS_COND_EQ:
518 uasm_i_beq(&p, reg1, reg2, imm);
519 break;
520 case MIPS_COND_NE:
521 uasm_i_bne(&p, reg1, reg2, imm);
522 break;
523 case MIPS_COND_ALL:
524 uasm_i_b(&p, imm);
525 break;
526 default:
527 pr_warn("%s: Unhandled branch conditional: %d\n",
528 __func__, cond);
529 }
530 }
531 ctx->idx++;
532}
533
534static inline void emit_b(unsigned int imm, struct jit_ctx *ctx)
535{
536 emit_bcond(MIPS_COND_ALL, r_zero, r_zero, imm, ctx);
537}
538
539static inline void emit_jalr(unsigned int link, unsigned int reg,
540 struct jit_ctx *ctx)
541{
542 emit_instr(ctx, jalr, link, reg);
543}
544
545static inline void emit_jr(unsigned int reg, struct jit_ctx *ctx)
546{
547 emit_instr(ctx, jr, reg);
548}
549
550static inline u16 align_sp(unsigned int num)
551{
552 /* Double word alignment for 32-bit, quadword for 64-bit */
553 unsigned int align = config_enabled(CONFIG_64BIT) ? 16 : 8;
554 num = (num + (align - 1)) & -align;
555 return num;
556}
557
Markos Chandrasc6610de2014-04-08 12:47:14 +0100558static bool is_load_to_a(u16 inst)
559{
560 switch (inst) {
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200561 case BPF_LD | BPF_W | BPF_LEN:
562 case BPF_LD | BPF_W | BPF_ABS:
563 case BPF_LD | BPF_H | BPF_ABS:
564 case BPF_LD | BPF_B | BPF_ABS:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100565 return true;
566 default:
567 return false;
568 }
569}
570
571static void save_bpf_jit_regs(struct jit_ctx *ctx, unsigned offset)
572{
573 int i = 0, real_off = 0;
574 u32 sflags, tmp_flags;
575
576 /* Adjust the stack pointer */
577 emit_stack_offset(-align_sp(offset), ctx);
578
579 if (ctx->flags & SEEN_CALL) {
580 /* Argument save area */
581 if (config_enabled(CONFIG_64BIT))
582 /* Bottom of current frame */
583 real_off = align_sp(offset) - RSIZE;
584 else
585 /* Top of previous frame */
586 real_off = align_sp(offset) + RSIZE;
587 emit_store_stack_reg(MIPS_R_A0, r_sp, real_off, ctx);
588 emit_store_stack_reg(MIPS_R_A1, r_sp, real_off + RSIZE, ctx);
589
590 real_off = 0;
591 }
592
593 tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT;
594 /* sflags is essentially a bitmap */
595 while (tmp_flags) {
596 if ((sflags >> i) & 0x1) {
597 emit_store_stack_reg(MIPS_R_S0 + i, r_sp, real_off,
598 ctx);
599 real_off += RSIZE;
600 }
601 i++;
602 tmp_flags >>= 1;
603 }
604
605 /* save return address */
606 if (ctx->flags & SEEN_CALL) {
607 emit_store_stack_reg(r_ra, r_sp, real_off, ctx);
608 real_off += RSIZE;
609 }
610
611 /* Setup r_M leaving the alignment gap if necessary */
612 if (ctx->flags & SEEN_MEM) {
613 if (real_off % (RSIZE * 2))
614 real_off += RSIZE;
615 emit_addiu(r_M, r_sp, real_off, ctx);
616 }
617}
618
619static void restore_bpf_jit_regs(struct jit_ctx *ctx,
620 unsigned int offset)
621{
622 int i, real_off = 0;
623 u32 sflags, tmp_flags;
624
625 if (ctx->flags & SEEN_CALL) {
626 if (config_enabled(CONFIG_64BIT))
627 /* Bottom of current frame */
628 real_off = align_sp(offset) - RSIZE;
629 else
630 /* Top of previous frame */
631 real_off = align_sp(offset) + RSIZE;
632 emit_load_stack_reg(MIPS_R_A0, r_sp, real_off, ctx);
633 emit_load_stack_reg(MIPS_R_A1, r_sp, real_off + RSIZE, ctx);
634
635 real_off = 0;
636 }
637
638 tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT;
639 /* sflags is a bitmap */
640 i = 0;
641 while (tmp_flags) {
642 if ((sflags >> i) & 0x1) {
643 emit_load_stack_reg(MIPS_R_S0 + i, r_sp, real_off,
644 ctx);
645 real_off += RSIZE;
646 }
647 i++;
648 tmp_flags >>= 1;
649 }
650
651 /* restore return address */
652 if (ctx->flags & SEEN_CALL)
653 emit_load_stack_reg(r_ra, r_sp, real_off, ctx);
654
655 /* Restore the sp and discard the scrach memory */
656 emit_stack_offset(align_sp(offset), ctx);
657}
658
659static unsigned int get_stack_depth(struct jit_ctx *ctx)
660{
661 int sp_off = 0;
662
663
664 /* How may s* regs do we need to preserved? */
665 sp_off += hweight32(ctx->flags >> SEEN_SREG_SFT) * RSIZE;
666
667 if (ctx->flags & SEEN_MEM)
668 sp_off += 4 * BPF_MEMWORDS; /* BPF_MEMWORDS are 32-bit */
669
670 if (ctx->flags & SEEN_CALL)
671 /*
672 * The JIT code make calls to external functions using 2
673 * arguments. Therefore, for o32 we don't need to allocate
674 * space because we don't care if the argumetns are lost
675 * across calls. We do need however to preserve incoming
676 * arguments but the space is already allocated for us by
677 * the caller. On the other hand, for n64, we need to allocate
678 * this space ourselves. We need to preserve $ra as well.
679 */
680 sp_off += config_enabled(CONFIG_64BIT) ?
681 (ARGS_USED_BY_JIT + 1) * RSIZE : RSIZE;
682
683 /*
684 * Subtract the bytes for the last registers since we only care about
685 * the location on the stack pointer.
686 */
687 return sp_off - RSIZE;
688}
689
690static void build_prologue(struct jit_ctx *ctx)
691{
692 u16 first_inst = ctx->skf->insns[0].code;
693 int sp_off;
694
695 /* Calculate the total offset for the stack pointer */
696 sp_off = get_stack_depth(ctx);
697 save_bpf_jit_regs(ctx, sp_off);
698
699 if (ctx->flags & SEEN_SKB)
700 emit_reg_move(r_skb, MIPS_R_A0, ctx);
701
Markos Chandrase5bb48b2014-06-23 10:38:56 +0100702 if (ctx->flags & SEEN_X)
Markos Chandrasc6610de2014-04-08 12:47:14 +0100703 emit_jit_reg_move(r_X, r_zero, ctx);
704
705 /* Do not leak kernel data to userspace */
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200706 if ((first_inst != (BPF_RET | BPF_K)) && !(is_load_to_a(first_inst)))
Markos Chandrasc6610de2014-04-08 12:47:14 +0100707 emit_jit_reg_move(r_A, r_zero, ctx);
708}
709
710static void build_epilogue(struct jit_ctx *ctx)
711{
712 unsigned int sp_off;
713
714 /* Calculate the total offset for the stack pointer */
715
716 sp_off = get_stack_depth(ctx);
717 restore_bpf_jit_regs(ctx, sp_off);
718
719 /* Return */
720 emit_jr(r_ra, ctx);
721 emit_nop(ctx);
722}
723
724static u64 jit_get_skb_b(struct sk_buff *skb, unsigned offset)
725{
726 u8 ret;
727 int err;
728
729 err = skb_copy_bits(skb, offset, &ret, 1);
730
731 return (u64)err << 32 | ret;
732}
733
734static u64 jit_get_skb_h(struct sk_buff *skb, unsigned offset)
735{
736 u16 ret;
737 int err;
738
739 err = skb_copy_bits(skb, offset, &ret, 2);
740
741 return (u64)err << 32 | ntohs(ret);
742}
743
744static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset)
745{
746 u32 ret;
747 int err;
748
749 err = skb_copy_bits(skb, offset, &ret, 4);
750
751 return (u64)err << 32 | ntohl(ret);
752}
753
Markos Chandrasb4fe0ec2014-06-23 10:38:58 +0100754#ifdef __BIG_ENDIAN_BITFIELD
755#define PKT_TYPE_MAX (7 << 5)
756#else
757#define PKT_TYPE_MAX 7
758#endif
Markos Chandrasc6610de2014-04-08 12:47:14 +0100759static int pkt_type_offset(void)
760{
761 struct sk_buff skb_probe = {
762 .pkt_type = ~0,
763 };
Markos Chandrasb4fe0ec2014-06-23 10:38:58 +0100764 u8 *ct = (u8 *)&skb_probe;
Markos Chandrasc6610de2014-04-08 12:47:14 +0100765 unsigned int off;
766
767 for (off = 0; off < sizeof(struct sk_buff); off++) {
768 if (ct[off] == PKT_TYPE_MAX)
769 return off;
770 }
771 pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
772 return -1;
773}
774
775static int build_body(struct jit_ctx *ctx)
776{
777 void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
778 const struct sk_filter *prog = ctx->skf;
779 const struct sock_filter *inst;
780 unsigned int i, off, load_order, condt;
781 u32 k, b_off __maybe_unused;
782
783 for (i = 0; i < prog->len; i++) {
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200784 u16 code;
785
Markos Chandrasc6610de2014-04-08 12:47:14 +0100786 inst = &(prog->insns[i]);
787 pr_debug("%s: code->0x%02x, jt->0x%x, jf->0x%x, k->0x%x\n",
788 __func__, inst->code, inst->jt, inst->jf, inst->k);
789 k = inst->k;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200790 code = bpf_anc_helper(inst);
Markos Chandrasc6610de2014-04-08 12:47:14 +0100791
792 if (ctx->target == NULL)
793 ctx->offsets[i] = ctx->idx * 4;
794
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200795 switch (code) {
796 case BPF_LD | BPF_IMM:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100797 /* A <- k ==> li r_A, k */
798 ctx->flags |= SEEN_A;
799 emit_load_imm(r_A, k, ctx);
800 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200801 case BPF_LD | BPF_W | BPF_LEN:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100802 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
803 /* A <- len ==> lw r_A, offset(skb) */
804 ctx->flags |= SEEN_SKB | SEEN_A;
805 off = offsetof(struct sk_buff, len);
806 emit_load(r_A, r_skb, off, ctx);
807 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200808 case BPF_LD | BPF_MEM:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100809 /* A <- M[k] ==> lw r_A, offset(M) */
810 ctx->flags |= SEEN_MEM | SEEN_A;
811 emit_load(r_A, r_M, SCRATCH_OFF(k), ctx);
812 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200813 case BPF_LD | BPF_W | BPF_ABS:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100814 /* A <- P[k:4] */
815 load_order = 2;
816 goto load;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200817 case BPF_LD | BPF_H | BPF_ABS:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100818 /* A <- P[k:2] */
819 load_order = 1;
820 goto load;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200821 case BPF_LD | BPF_B | BPF_ABS:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100822 /* A <- P[k:1] */
823 load_order = 0;
824load:
Markos Chandras55393ee2014-06-23 10:38:48 +0100825 /* the interpreter will deal with the negative K */
826 if ((int)k < 0)
827 return -ENOTSUPP;
828
Markos Chandrasc6610de2014-04-08 12:47:14 +0100829 emit_load_imm(r_off, k, ctx);
830load_common:
Markos Chandras55393ee2014-06-23 10:38:48 +0100831 /*
832 * We may got here from the indirect loads so
833 * return if offset is negative.
834 */
835 emit_slt(r_s0, r_off, r_zero, ctx);
836 emit_bcond(MIPS_COND_NE, r_s0, r_zero,
837 b_imm(prog->len, ctx), ctx);
838 emit_reg_move(r_ret, r_zero, ctx);
839
Markos Chandrasc6610de2014-04-08 12:47:14 +0100840 ctx->flags |= SEEN_CALL | SEEN_OFF | SEEN_S0 |
841 SEEN_SKB | SEEN_A;
842
843 emit_load_func(r_s0, (ptr)load_func[load_order],
844 ctx);
845 emit_reg_move(MIPS_R_A0, r_skb, ctx);
846 emit_jalr(MIPS_R_RA, r_s0, ctx);
847 /* Load second argument to delay slot */
848 emit_reg_move(MIPS_R_A1, r_off, ctx);
849 /* Check the error value */
850 if (config_enabled(CONFIG_64BIT)) {
851 /* Get error code from the top 32-bits */
852 emit_dsrl32(r_s0, r_val, 0, ctx);
853 /* Branch to 3 instructions ahead */
854 emit_bcond(MIPS_COND_NE, r_s0, r_zero, 3 << 2,
855 ctx);
856 } else {
857 /* Branch to 3 instructions ahead */
858 emit_bcond(MIPS_COND_NE, r_err, r_zero, 3 << 2,
859 ctx);
860 }
861 emit_nop(ctx);
862 /* We are good */
863 emit_b(b_imm(i + 1, ctx), ctx);
864 emit_jit_reg_move(r_A, r_val, ctx);
865 /* Return with error */
866 emit_b(b_imm(prog->len, ctx), ctx);
867 emit_reg_move(r_ret, r_zero, ctx);
868 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200869 case BPF_LD | BPF_W | BPF_IND:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100870 /* A <- P[X + k:4] */
871 load_order = 2;
872 goto load_ind;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200873 case BPF_LD | BPF_H | BPF_IND:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100874 /* A <- P[X + k:2] */
875 load_order = 1;
876 goto load_ind;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200877 case BPF_LD | BPF_B | BPF_IND:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100878 /* A <- P[X + k:1] */
879 load_order = 0;
880load_ind:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100881 ctx->flags |= SEEN_OFF | SEEN_X;
882 emit_addiu(r_off, r_X, k, ctx);
883 goto load_common;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200884 case BPF_LDX | BPF_IMM:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100885 /* X <- k */
886 ctx->flags |= SEEN_X;
887 emit_load_imm(r_X, k, ctx);
888 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200889 case BPF_LDX | BPF_MEM:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100890 /* X <- M[k] */
891 ctx->flags |= SEEN_X | SEEN_MEM;
892 emit_load(r_X, r_M, SCRATCH_OFF(k), ctx);
893 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200894 case BPF_LDX | BPF_W | BPF_LEN:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100895 /* X <- len */
896 ctx->flags |= SEEN_X | SEEN_SKB;
897 off = offsetof(struct sk_buff, len);
898 emit_load(r_X, r_skb, off, ctx);
899 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200900 case BPF_LDX | BPF_B | BPF_MSH:
Markos Chandras55393ee2014-06-23 10:38:48 +0100901 /* the interpreter will deal with the negative K */
902 if ((int)k < 0)
903 return -ENOTSUPP;
904
Markos Chandrasc6610de2014-04-08 12:47:14 +0100905 /* X <- 4 * (P[k:1] & 0xf) */
906 ctx->flags |= SEEN_X | SEEN_CALL | SEEN_S0 | SEEN_SKB;
907 /* Load offset to a1 */
908 emit_load_func(r_s0, (ptr)jit_get_skb_b, ctx);
909 /*
910 * This may emit two instructions so it may not fit
911 * in the delay slot. So use a0 in the delay slot.
912 */
913 emit_load_imm(MIPS_R_A1, k, ctx);
914 emit_jalr(MIPS_R_RA, r_s0, ctx);
915 emit_reg_move(MIPS_R_A0, r_skb, ctx); /* delay slot */
916 /* Check the error value */
917 if (config_enabled(CONFIG_64BIT)) {
918 /* Top 32-bits of $v0 on 64-bit */
919 emit_dsrl32(r_s0, r_val, 0, ctx);
920 emit_bcond(MIPS_COND_NE, r_s0, r_zero,
921 3 << 2, ctx);
922 } else {
923 emit_bcond(MIPS_COND_NE, r_err, r_zero,
924 3 << 2, ctx);
925 }
926 /* No need for delay slot */
927 /* We are good */
928 /* X <- P[1:K] & 0xf */
929 emit_andi(r_X, r_val, 0xf, ctx);
930 /* X << 2 */
931 emit_b(b_imm(i + 1, ctx), ctx);
932 emit_sll(r_X, r_X, 2, ctx); /* delay slot */
933 /* Return with error */
934 emit_b(b_imm(prog->len, ctx), ctx);
935 emit_load_imm(r_ret, 0, ctx); /* delay slot */
936 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200937 case BPF_ST:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100938 /* M[k] <- A */
939 ctx->flags |= SEEN_MEM | SEEN_A;
940 emit_store(r_A, r_M, SCRATCH_OFF(k), ctx);
941 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200942 case BPF_STX:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100943 /* M[k] <- X */
944 ctx->flags |= SEEN_MEM | SEEN_X;
945 emit_store(r_X, r_M, SCRATCH_OFF(k), ctx);
946 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200947 case BPF_ALU | BPF_ADD | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100948 /* A += K */
949 ctx->flags |= SEEN_A;
950 emit_addiu(r_A, r_A, k, ctx);
951 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200952 case BPF_ALU | BPF_ADD | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100953 /* A += X */
954 ctx->flags |= SEEN_A | SEEN_X;
955 emit_addu(r_A, r_A, r_X, ctx);
956 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200957 case BPF_ALU | BPF_SUB | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100958 /* A -= K */
959 ctx->flags |= SEEN_A;
960 emit_addiu(r_A, r_A, -k, ctx);
961 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200962 case BPF_ALU | BPF_SUB | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100963 /* A -= X */
964 ctx->flags |= SEEN_A | SEEN_X;
965 emit_subu(r_A, r_A, r_X, ctx);
966 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200967 case BPF_ALU | BPF_MUL | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100968 /* A *= K */
969 /* Load K to scratch register before MUL */
970 ctx->flags |= SEEN_A | SEEN_S0;
971 emit_load_imm(r_s0, k, ctx);
972 emit_mul(r_A, r_A, r_s0, ctx);
973 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200974 case BPF_ALU | BPF_MUL | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100975 /* A *= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +0100976 ctx->flags |= SEEN_A | SEEN_X;
977 emit_mul(r_A, r_A, r_X, ctx);
978 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200979 case BPF_ALU | BPF_DIV | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100980 /* A /= k */
981 if (k == 1)
982 break;
983 if (optimize_div(&k)) {
984 ctx->flags |= SEEN_A;
985 emit_srl(r_A, r_A, k, ctx);
986 break;
987 }
988 ctx->flags |= SEEN_A | SEEN_S0;
989 emit_load_imm(r_s0, k, ctx);
990 emit_div(r_A, r_s0, ctx);
991 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +0200992 case BPF_ALU | BPF_MOD | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +0100993 /* A %= k */
994 if (k == 1 || optimize_div(&k)) {
995 ctx->flags |= SEEN_A;
996 emit_jit_reg_move(r_A, r_zero, ctx);
997 } else {
998 ctx->flags |= SEEN_A | SEEN_S0;
999 emit_load_imm(r_s0, k, ctx);
1000 emit_mod(r_A, r_s0, ctx);
1001 }
1002 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001003 case BPF_ALU | BPF_DIV | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001004 /* A /= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +01001005 ctx->flags |= SEEN_X | SEEN_A;
1006 /* Check if r_X is zero */
1007 emit_bcond(MIPS_COND_EQ, r_X, r_zero,
1008 b_imm(prog->len, ctx), ctx);
1009 emit_load_imm(r_val, 0, ctx); /* delay slot */
1010 emit_div(r_A, r_X, ctx);
1011 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001012 case BPF_ALU | BPF_MOD | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001013 /* A %= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +01001014 ctx->flags |= SEEN_X | SEEN_A;
1015 /* Check if r_X is zero */
1016 emit_bcond(MIPS_COND_EQ, r_X, r_zero,
1017 b_imm(prog->len, ctx), ctx);
1018 emit_load_imm(r_val, 0, ctx); /* delay slot */
1019 emit_mod(r_A, r_X, ctx);
1020 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001021 case BPF_ALU | BPF_OR | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001022 /* A |= K */
1023 ctx->flags |= SEEN_A;
1024 emit_ori(r_A, r_A, k, ctx);
1025 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001026 case BPF_ALU | BPF_OR | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001027 /* A |= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +01001028 ctx->flags |= SEEN_A;
1029 emit_ori(r_A, r_A, r_X, ctx);
1030 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001031 case BPF_ALU | BPF_XOR | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001032 /* A ^= k */
1033 ctx->flags |= SEEN_A;
1034 emit_xori(r_A, r_A, k, ctx);
1035 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001036 case BPF_ANC | SKF_AD_ALU_XOR_X:
1037 case BPF_ALU | BPF_XOR | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001038 /* A ^= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +01001039 ctx->flags |= SEEN_A;
1040 emit_xor(r_A, r_A, r_X, ctx);
1041 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001042 case BPF_ALU | BPF_AND | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001043 /* A &= K */
1044 ctx->flags |= SEEN_A;
1045 emit_andi(r_A, r_A, k, ctx);
1046 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001047 case BPF_ALU | BPF_AND | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001048 /* A &= X */
Markos Chandrasc6610de2014-04-08 12:47:14 +01001049 ctx->flags |= SEEN_A | SEEN_X;
1050 emit_and(r_A, r_A, r_X, ctx);
1051 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001052 case BPF_ALU | BPF_LSH | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001053 /* A <<= K */
1054 ctx->flags |= SEEN_A;
1055 emit_sll(r_A, r_A, k, ctx);
1056 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001057 case BPF_ALU | BPF_LSH | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001058 /* A <<= X */
1059 ctx->flags |= SEEN_A | SEEN_X;
Markos Chandrasc6610de2014-04-08 12:47:14 +01001060 emit_sllv(r_A, r_A, r_X, ctx);
1061 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001062 case BPF_ALU | BPF_RSH | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001063 /* A >>= K */
1064 ctx->flags |= SEEN_A;
1065 emit_srl(r_A, r_A, k, ctx);
1066 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001067 case BPF_ALU | BPF_RSH | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001068 ctx->flags |= SEEN_A | SEEN_X;
Markos Chandrasc6610de2014-04-08 12:47:14 +01001069 emit_srlv(r_A, r_A, r_X, ctx);
1070 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001071 case BPF_ALU | BPF_NEG:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001072 /* A = -A */
1073 ctx->flags |= SEEN_A;
1074 emit_neg(r_A, ctx);
1075 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001076 case BPF_JMP | BPF_JA:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001077 /* pc += K */
1078 emit_b(b_imm(i + k + 1, ctx), ctx);
1079 emit_nop(ctx);
1080 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001081 case BPF_JMP | BPF_JEQ | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001082 /* pc += ( A == K ) ? pc->jt : pc->jf */
1083 condt = MIPS_COND_EQ | MIPS_COND_K;
1084 goto jmp_cmp;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001085 case BPF_JMP | BPF_JEQ | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001086 ctx->flags |= SEEN_X;
1087 /* pc += ( A == X ) ? pc->jt : pc->jf */
1088 condt = MIPS_COND_EQ | MIPS_COND_X;
1089 goto jmp_cmp;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001090 case BPF_JMP | BPF_JGE | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001091 /* pc += ( A >= K ) ? pc->jt : pc->jf */
1092 condt = MIPS_COND_GE | MIPS_COND_K;
1093 goto jmp_cmp;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001094 case BPF_JMP | BPF_JGE | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001095 ctx->flags |= SEEN_X;
1096 /* pc += ( A >= X ) ? pc->jt : pc->jf */
1097 condt = MIPS_COND_GE | MIPS_COND_X;
1098 goto jmp_cmp;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001099 case BPF_JMP | BPF_JGT | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001100 /* pc += ( A > K ) ? pc->jt : pc->jf */
1101 condt = MIPS_COND_GT | MIPS_COND_K;
1102 goto jmp_cmp;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001103 case BPF_JMP | BPF_JGT | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001104 ctx->flags |= SEEN_X;
1105 /* pc += ( A > X ) ? pc->jt : pc->jf */
1106 condt = MIPS_COND_GT | MIPS_COND_X;
1107jmp_cmp:
1108 /* Greater or Equal */
1109 if ((condt & MIPS_COND_GE) ||
1110 (condt & MIPS_COND_GT)) {
1111 if (condt & MIPS_COND_K) { /* K */
1112 ctx->flags |= SEEN_S0 | SEEN_A;
1113 emit_sltiu(r_s0, r_A, k, ctx);
1114 } else { /* X */
1115 ctx->flags |= SEEN_S0 | SEEN_A |
1116 SEEN_X;
1117 emit_sltu(r_s0, r_A, r_X, ctx);
1118 }
1119 /* A < (K|X) ? r_scrach = 1 */
1120 b_off = b_imm(i + inst->jf + 1, ctx);
Markos Chandras1ab24a42014-06-23 10:38:51 +01001121 emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off,
Markos Chandrasc6610de2014-04-08 12:47:14 +01001122 ctx);
1123 emit_nop(ctx);
1124 /* A > (K|X) ? scratch = 0 */
1125 if (condt & MIPS_COND_GT) {
1126 /* Checking for equality */
1127 ctx->flags |= SEEN_S0 | SEEN_A | SEEN_X;
1128 if (condt & MIPS_COND_K)
1129 emit_load_imm(r_s0, k, ctx);
1130 else
1131 emit_jit_reg_move(r_s0, r_X,
1132 ctx);
1133 b_off = b_imm(i + inst->jf + 1, ctx);
1134 emit_bcond(MIPS_COND_EQ, r_A, r_s0,
1135 b_off, ctx);
1136 emit_nop(ctx);
1137 /* Finally, A > K|X */
1138 b_off = b_imm(i + inst->jt + 1, ctx);
1139 emit_b(b_off, ctx);
1140 emit_nop(ctx);
1141 } else {
1142 /* A >= (K|X) so jump */
1143 b_off = b_imm(i + inst->jt + 1, ctx);
1144 emit_b(b_off, ctx);
1145 emit_nop(ctx);
1146 }
1147 } else {
1148 /* A == K|X */
1149 if (condt & MIPS_COND_K) { /* K */
1150 ctx->flags |= SEEN_S0 | SEEN_A;
1151 emit_load_imm(r_s0, k, ctx);
1152 /* jump true */
1153 b_off = b_imm(i + inst->jt + 1, ctx);
1154 emit_bcond(MIPS_COND_EQ, r_A, r_s0,
1155 b_off, ctx);
1156 emit_nop(ctx);
1157 /* jump false */
1158 b_off = b_imm(i + inst->jf + 1,
1159 ctx);
1160 emit_bcond(MIPS_COND_NE, r_A, r_s0,
1161 b_off, ctx);
1162 emit_nop(ctx);
1163 } else { /* X */
1164 /* jump true */
1165 ctx->flags |= SEEN_A | SEEN_X;
1166 b_off = b_imm(i + inst->jt + 1,
1167 ctx);
1168 emit_bcond(MIPS_COND_EQ, r_A, r_X,
1169 b_off, ctx);
1170 emit_nop(ctx);
1171 /* jump false */
1172 b_off = b_imm(i + inst->jf + 1, ctx);
1173 emit_bcond(MIPS_COND_NE, r_A, r_X,
1174 b_off, ctx);
1175 emit_nop(ctx);
1176 }
1177 }
1178 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001179 case BPF_JMP | BPF_JSET | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001180 ctx->flags |= SEEN_S0 | SEEN_S1 | SEEN_A;
1181 /* pc += (A & K) ? pc -> jt : pc -> jf */
1182 emit_load_imm(r_s1, k, ctx);
1183 emit_and(r_s0, r_A, r_s1, ctx);
1184 /* jump true */
1185 b_off = b_imm(i + inst->jt + 1, ctx);
1186 emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx);
1187 emit_nop(ctx);
1188 /* jump false */
1189 b_off = b_imm(i + inst->jf + 1, ctx);
1190 emit_b(b_off, ctx);
1191 emit_nop(ctx);
1192 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001193 case BPF_JMP | BPF_JSET | BPF_X:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001194 ctx->flags |= SEEN_S0 | SEEN_X | SEEN_A;
1195 /* pc += (A & X) ? pc -> jt : pc -> jf */
1196 emit_and(r_s0, r_A, r_X, ctx);
1197 /* jump true */
1198 b_off = b_imm(i + inst->jt + 1, ctx);
1199 emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx);
1200 emit_nop(ctx);
1201 /* jump false */
1202 b_off = b_imm(i + inst->jf + 1, ctx);
1203 emit_b(b_off, ctx);
1204 emit_nop(ctx);
1205 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001206 case BPF_RET | BPF_A:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001207 ctx->flags |= SEEN_A;
1208 if (i != prog->len - 1)
1209 /*
1210 * If this is not the last instruction
1211 * then jump to the epilogue
1212 */
1213 emit_b(b_imm(prog->len, ctx), ctx);
1214 emit_reg_move(r_ret, r_A, ctx); /* delay slot */
1215 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001216 case BPF_RET | BPF_K:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001217 /*
1218 * It can emit two instructions so it does not fit on
1219 * the delay slot.
1220 */
1221 emit_load_imm(r_ret, k, ctx);
1222 if (i != prog->len - 1) {
1223 /*
1224 * If this is not the last instruction
1225 * then jump to the epilogue
1226 */
1227 emit_b(b_imm(prog->len, ctx), ctx);
1228 emit_nop(ctx);
1229 }
1230 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001231 case BPF_MISC | BPF_TAX:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001232 /* X = A */
1233 ctx->flags |= SEEN_X | SEEN_A;
1234 emit_jit_reg_move(r_X, r_A, ctx);
1235 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001236 case BPF_MISC | BPF_TXA:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001237 /* A = X */
1238 ctx->flags |= SEEN_A | SEEN_X;
Markos Chandrasc6610de2014-04-08 12:47:14 +01001239 emit_jit_reg_move(r_A, r_X, ctx);
1240 break;
1241 /* AUX */
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001242 case BPF_ANC | SKF_AD_PROTOCOL:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001243 /* A = ntohs(skb->protocol */
1244 ctx->flags |= SEEN_SKB | SEEN_OFF | SEEN_A;
1245 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1246 protocol) != 2);
1247 off = offsetof(struct sk_buff, protocol);
1248 emit_half_load(r_A, r_skb, off, ctx);
1249#ifdef CONFIG_CPU_LITTLE_ENDIAN
1250 /* This needs little endian fixup */
Ralf Baechleb4f16c92014-06-03 13:05:55 +02001251 if (cpu_has_mips_r2) {
1252 /* R2 and later have the wsbh instruction */
1253 emit_wsbh(r_A, r_A, ctx);
1254 } else {
Markos Chandrasc6610de2014-04-08 12:47:14 +01001255 /* Get first byte */
1256 emit_andi(r_tmp_imm, r_A, 0xff, ctx);
1257 /* Shift it */
1258 emit_sll(r_tmp, r_tmp_imm, 8, ctx);
1259 /* Get second byte */
1260 emit_srl(r_tmp_imm, r_A, 8, ctx);
1261 emit_andi(r_tmp_imm, r_tmp_imm, 0xff, ctx);
1262 /* Put everyting together in r_A */
1263 emit_or(r_A, r_tmp, r_tmp_imm, ctx);
Markos Chandrasc6610de2014-04-08 12:47:14 +01001264 }
1265#endif
1266 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001267 case BPF_ANC | SKF_AD_CPU:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001268 ctx->flags |= SEEN_A | SEEN_OFF;
1269 /* A = current_thread_info()->cpu */
1270 BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info,
1271 cpu) != 4);
1272 off = offsetof(struct thread_info, cpu);
1273 /* $28/gp points to the thread_info struct */
1274 emit_load(r_A, 28, off, ctx);
1275 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001276 case BPF_ANC | SKF_AD_IFINDEX:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001277 /* A = skb->dev->ifindex */
1278 ctx->flags |= SEEN_SKB | SEEN_A | SEEN_S0;
1279 off = offsetof(struct sk_buff, dev);
1280 emit_load(r_s0, r_skb, off, ctx);
1281 /* error (0) in the delay slot */
1282 emit_bcond(MIPS_COND_EQ, r_s0, r_zero,
1283 b_imm(prog->len, ctx), ctx);
1284 emit_reg_move(r_ret, r_zero, ctx);
1285 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
1286 ifindex) != 4);
1287 off = offsetof(struct net_device, ifindex);
1288 emit_load(r_A, r_s0, off, ctx);
1289 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001290 case BPF_ANC | SKF_AD_MARK:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001291 ctx->flags |= SEEN_SKB | SEEN_A;
1292 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
1293 off = offsetof(struct sk_buff, mark);
1294 emit_load(r_A, r_skb, off, ctx);
1295 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001296 case BPF_ANC | SKF_AD_RXHASH:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001297 ctx->flags |= SEEN_SKB | SEEN_A;
1298 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
1299 off = offsetof(struct sk_buff, hash);
1300 emit_load(r_A, r_skb, off, ctx);
1301 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001302 case BPF_ANC | SKF_AD_VLAN_TAG:
1303 case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001304 ctx->flags |= SEEN_SKB | SEEN_S0 | SEEN_A;
1305 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1306 vlan_tci) != 2);
1307 off = offsetof(struct sk_buff, vlan_tci);
1308 emit_half_load(r_s0, r_skb, off, ctx);
Markos Chandras91a41d72014-06-23 10:38:53 +01001309 if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
Markos Chandras6e86c592014-06-23 10:38:52 +01001310 emit_andi(r_A, r_s0, (u16)~VLAN_TAG_PRESENT, ctx);
Markos Chandras91a41d72014-06-23 10:38:53 +01001311 } else {
Markos Chandras9ee16062014-06-23 10:38:49 +01001312 emit_andi(r_A, r_s0, VLAN_TAG_PRESENT, ctx);
Markos Chandras91a41d72014-06-23 10:38:53 +01001313 /* return 1 if present */
1314 emit_sltu(r_A, r_zero, r_A, ctx);
1315 }
Markos Chandrasc6610de2014-04-08 12:47:14 +01001316 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001317 case BPF_ANC | SKF_AD_PKTTYPE:
Markos Chandras9eebfe42014-06-23 10:38:50 +01001318 ctx->flags |= SEEN_SKB;
1319
Markos Chandrasc6610de2014-04-08 12:47:14 +01001320 off = pkt_type_offset();
1321
1322 if (off < 0)
1323 return -1;
1324 emit_load_byte(r_tmp, r_skb, off, ctx);
1325 /* Keep only the last 3 bits */
1326 emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
Markos Chandrasb4fe0ec2014-06-23 10:38:58 +01001327#ifdef __BIG_ENDIAN_BITFIELD
1328 /* Get the actual packet type to the lower 3 bits */
1329 emit_srl(r_A, r_A, 5, ctx);
1330#endif
Markos Chandrasc6610de2014-04-08 12:47:14 +01001331 break;
Daniel Borkmanna83d0812014-06-17 12:16:18 +02001332 case BPF_ANC | SKF_AD_QUEUE:
Markos Chandrasc6610de2014-04-08 12:47:14 +01001333 ctx->flags |= SEEN_SKB | SEEN_A;
1334 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1335 queue_mapping) != 2);
1336 BUILD_BUG_ON(offsetof(struct sk_buff,
1337 queue_mapping) > 0xff);
1338 off = offsetof(struct sk_buff, queue_mapping);
1339 emit_half_load(r_A, r_skb, off, ctx);
1340 break;
1341 default:
Markos Chandras78b95b62014-06-23 10:38:54 +01001342 pr_debug("%s: Unhandled opcode: 0x%02x\n", __FILE__,
1343 inst->code);
Markos Chandrasc6610de2014-04-08 12:47:14 +01001344 return -1;
1345 }
1346 }
1347
1348 /* compute offsets only during the first pass */
1349 if (ctx->target == NULL)
1350 ctx->offsets[i] = ctx->idx * 4;
1351
1352 return 0;
1353}
1354
1355int bpf_jit_enable __read_mostly;
1356
1357void bpf_jit_compile(struct sk_filter *fp)
1358{
1359 struct jit_ctx ctx;
1360 unsigned int alloc_size, tmp_idx;
1361
1362 if (!bpf_jit_enable)
1363 return;
1364
1365 memset(&ctx, 0, sizeof(ctx));
1366
1367 ctx.offsets = kcalloc(fp->len, sizeof(*ctx.offsets), GFP_KERNEL);
1368 if (ctx.offsets == NULL)
1369 return;
1370
1371 ctx.skf = fp;
1372
1373 if (build_body(&ctx))
1374 goto out;
1375
1376 tmp_idx = ctx.idx;
1377 build_prologue(&ctx);
1378 ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
1379 /* just to complete the ctx.idx count */
1380 build_epilogue(&ctx);
1381
1382 alloc_size = 4 * ctx.idx;
1383 ctx.target = module_alloc(alloc_size);
1384 if (ctx.target == NULL)
1385 goto out;
1386
1387 /* Clean it */
1388 memset(ctx.target, 0, alloc_size);
1389
1390 ctx.idx = 0;
1391
1392 /* Generate the actual JIT code */
1393 build_prologue(&ctx);
1394 build_body(&ctx);
1395 build_epilogue(&ctx);
1396
1397 /* Update the icache */
1398 flush_icache_range((ptr)ctx.target, (ptr)(ctx.target + ctx.idx));
1399
1400 if (bpf_jit_enable > 1)
1401 /* Dump JIT code */
1402 bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
1403
1404 fp->bpf_func = (void *)ctx.target;
1405 fp->jited = 1;
1406
1407out:
1408 kfree(ctx.offsets);
1409}
1410
1411void bpf_jit_free(struct sk_filter *fp)
1412{
1413 if (fp->jited)
1414 module_free(NULL, fp->bpf_func);
1415 kfree(fp);
1416}