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TOMOYO Linux Cross Reference
Linux/arch/mips/net/bpf_jit.c

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Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  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/moduleloader.h>
 18 #include <linux/netdevice.h>
 19 #include <linux/string.h>
 20 #include <linux/slab.h>
 21 #include <linux/types.h>
 22 #include <asm/asm.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  * r_skb_hl     SKB header length
 32  * r_data       SKB data pointer
 33  * r_off        Offset
 34  * r_A          BPF register A
 35  * r_X          BPF register X
 36  * r_skb        *skb
 37  * r_M          *scratch memory
 38  * r_skb_len    SKB length
 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 ptr typeof(unsigned long)
 67 
 68 #define SCRATCH_OFF(k)          (4 * (k))
 69 
 70 /* JIT flags */
 71 #define SEEN_CALL               (1 << BPF_MEMWORDS)
 72 #define SEEN_SREG_SFT           (BPF_MEMWORDS + 1)
 73 #define SEEN_SREG_BASE          (1 << SEEN_SREG_SFT)
 74 #define SEEN_SREG(x)            (SEEN_SREG_BASE << (x))
 75 #define SEEN_OFF                SEEN_SREG(2)
 76 #define SEEN_A                  SEEN_SREG(3)
 77 #define SEEN_X                  SEEN_SREG(4)
 78 #define SEEN_SKB                SEEN_SREG(5)
 79 #define SEEN_MEM                SEEN_SREG(6)
 80 /* SEEN_SK_DATA also implies skb_hl an skb_len */
 81 #define SEEN_SKB_DATA           (SEEN_SREG(7) | SEEN_SREG(1) | SEEN_SREG(0))
 82 
 83 /* Arguments used by JIT */
 84 #define ARGS_USED_BY_JIT        2 /* only applicable to 64-bit */
 85 
 86 #define SBIT(x)                 (1 << (x)) /* Signed version of BIT() */
 87 
 88 /**
 89  * struct jit_ctx - JIT context
 90  * @skf:                The sk_filter
 91  * @prologue_bytes:     Number of bytes for prologue
 92  * @idx:                Instruction index
 93  * @flags:              JIT flags
 94  * @offsets:            Instruction offsets
 95  * @target:             Memory location for the compiled filter
 96  */
 97 struct jit_ctx {
 98         const struct bpf_prog *skf;
 99         unsigned int prologue_bytes;
100         u32 idx;
101         u32 flags;
102         u32 *offsets;
103         u32 *target;
104 };
105 
106 
107 static inline int optimize_div(u32 *k)
108 {
109         /* power of 2 divides can be implemented with right shift */
110         if (!(*k & (*k-1))) {
111                 *k = ilog2(*k);
112                 return 1;
113         }
114 
115         return 0;
116 }
117 
118 static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx);
119 
120 /* Simply emit the instruction if the JIT memory space has been allocated */
121 #define emit_instr(ctx, func, ...)                      \
122 do {                                                    \
123         if ((ctx)->target != NULL) {                    \
124                 u32 *p = &(ctx)->target[ctx->idx];      \
125                 uasm_i_##func(&p, ##__VA_ARGS__);       \
126         }                                               \
127         (ctx)->idx++;                                   \
128 } while (0)
129 
130 /*
131  * Similar to emit_instr but it must be used when we need to emit
132  * 32-bit or 64-bit instructions
133  */
134 #define emit_long_instr(ctx, func, ...)                 \
135 do {                                                    \
136         if ((ctx)->target != NULL) {                    \
137                 u32 *p = &(ctx)->target[ctx->idx];      \
138                 UASM_i_##func(&p, ##__VA_ARGS__);       \
139         }                                               \
140         (ctx)->idx++;                                   \
141 } while (0)
142 
143 /* Determine if immediate is within the 16-bit signed range */
144 static inline bool is_range16(s32 imm)
145 {
146         return !(imm >= SBIT(15) || imm < -SBIT(15));
147 }
148 
149 static inline void emit_addu(unsigned int dst, unsigned int src1,
150                              unsigned int src2, struct jit_ctx *ctx)
151 {
152         emit_instr(ctx, addu, dst, src1, src2);
153 }
154 
155 static inline void emit_nop(struct jit_ctx *ctx)
156 {
157         emit_instr(ctx, nop);
158 }
159 
160 /* Load a u32 immediate to a register */
161 static inline void emit_load_imm(unsigned int dst, u32 imm, struct jit_ctx *ctx)
162 {
163         if (ctx->target != NULL) {
164                 /* addiu can only handle s16 */
165                 if (!is_range16(imm)) {
166                         u32 *p = &ctx->target[ctx->idx];
167                         uasm_i_lui(&p, r_tmp_imm, (s32)imm >> 16);
168                         p = &ctx->target[ctx->idx + 1];
169                         uasm_i_ori(&p, dst, r_tmp_imm, imm & 0xffff);
170                 } else {
171                         u32 *p = &ctx->target[ctx->idx];
172                         uasm_i_addiu(&p, dst, r_zero, imm);
173                 }
174         }
175         ctx->idx++;
176 
177         if (!is_range16(imm))
178                 ctx->idx++;
179 }
180 
181 static inline void emit_or(unsigned int dst, unsigned int src1,
182                            unsigned int src2, struct jit_ctx *ctx)
183 {
184         emit_instr(ctx, or, dst, src1, src2);
185 }
186 
187 static inline void emit_ori(unsigned int dst, unsigned src, u32 imm,
188                             struct jit_ctx *ctx)
189 {
190         if (imm >= BIT(16)) {
191                 emit_load_imm(r_tmp, imm, ctx);
192                 emit_or(dst, src, r_tmp, ctx);
193         } else {
194                 emit_instr(ctx, ori, dst, src, imm);
195         }
196 }
197 
198 static inline void emit_daddiu(unsigned int dst, unsigned int src,
199                                int imm, struct jit_ctx *ctx)
200 {
201         /*
202          * Only used for stack, so the imm is relatively small
203          * and it fits in 15-bits
204          */
205         emit_instr(ctx, daddiu, dst, src, imm);
206 }
207 
208 static inline void emit_addiu(unsigned int dst, unsigned int src,
209                               u32 imm, struct jit_ctx *ctx)
210 {
211         if (!is_range16(imm)) {
212                 emit_load_imm(r_tmp, imm, ctx);
213                 emit_addu(dst, r_tmp, src, ctx);
214         } else {
215                 emit_instr(ctx, addiu, dst, src, imm);
216         }
217 }
218 
219 static inline void emit_and(unsigned int dst, unsigned int src1,
220                             unsigned int src2, struct jit_ctx *ctx)
221 {
222         emit_instr(ctx, and, dst, src1, src2);
223 }
224 
225 static inline void emit_andi(unsigned int dst, unsigned int src,
226                              u32 imm, struct jit_ctx *ctx)
227 {
228         /* If imm does not fit in u16 then load it to register */
229         if (imm >= BIT(16)) {
230                 emit_load_imm(r_tmp, imm, ctx);
231                 emit_and(dst, src, r_tmp, ctx);
232         } else {
233                 emit_instr(ctx, andi, dst, src, imm);
234         }
235 }
236 
237 static inline void emit_xor(unsigned int dst, unsigned int src1,
238                             unsigned int src2, struct jit_ctx *ctx)
239 {
240         emit_instr(ctx, xor, dst, src1, src2);
241 }
242 
243 static inline void emit_xori(ptr dst, ptr src, u32 imm, struct jit_ctx *ctx)
244 {
245         /* If imm does not fit in u16 then load it to register */
246         if (imm >= BIT(16)) {
247                 emit_load_imm(r_tmp, imm, ctx);
248                 emit_xor(dst, src, r_tmp, ctx);
249         } else {
250                 emit_instr(ctx, xori, dst, src, imm);
251         }
252 }
253 
254 static inline void emit_stack_offset(int offset, struct jit_ctx *ctx)
255 {
256         emit_long_instr(ctx, ADDIU, r_sp, r_sp, offset);
257 }
258 
259 static inline void emit_subu(unsigned int dst, unsigned int src1,
260                              unsigned int src2, struct jit_ctx *ctx)
261 {
262         emit_instr(ctx, subu, dst, src1, src2);
263 }
264 
265 static inline void emit_neg(unsigned int reg, struct jit_ctx *ctx)
266 {
267         emit_subu(reg, r_zero, reg, ctx);
268 }
269 
270 static inline void emit_sllv(unsigned int dst, unsigned int src,
271                              unsigned int sa, struct jit_ctx *ctx)
272 {
273         emit_instr(ctx, sllv, dst, src, sa);
274 }
275 
276 static inline void emit_sll(unsigned int dst, unsigned int src,
277                             unsigned int sa, struct jit_ctx *ctx)
278 {
279         /* sa is 5-bits long */
280         if (sa >= BIT(5))
281                 /* Shifting >= 32 results in zero */
282                 emit_jit_reg_move(dst, r_zero, ctx);
283         else
284                 emit_instr(ctx, sll, dst, src, sa);
285 }
286 
287 static inline void emit_srlv(unsigned int dst, unsigned int src,
288                              unsigned int sa, struct jit_ctx *ctx)
289 {
290         emit_instr(ctx, srlv, dst, src, sa);
291 }
292 
293 static inline void emit_srl(unsigned int dst, unsigned int src,
294                             unsigned int sa, struct jit_ctx *ctx)
295 {
296         /* sa is 5-bits long */
297         if (sa >= BIT(5))
298                 /* Shifting >= 32 results in zero */
299                 emit_jit_reg_move(dst, r_zero, ctx);
300         else
301                 emit_instr(ctx, srl, dst, src, sa);
302 }
303 
304 static inline void emit_slt(unsigned int dst, unsigned int src1,
305                             unsigned int src2, struct jit_ctx *ctx)
306 {
307         emit_instr(ctx, slt, dst, src1, src2);
308 }
309 
310 static inline void emit_sltu(unsigned int dst, unsigned int src1,
311                              unsigned int src2, struct jit_ctx *ctx)
312 {
313         emit_instr(ctx, sltu, dst, src1, src2);
314 }
315 
316 static inline void emit_sltiu(unsigned dst, unsigned int src,
317                               unsigned int imm, struct jit_ctx *ctx)
318 {
319         /* 16 bit immediate */
320         if (!is_range16((s32)imm)) {
321                 emit_load_imm(r_tmp, imm, ctx);
322                 emit_sltu(dst, src, r_tmp, ctx);
323         } else {
324                 emit_instr(ctx, sltiu, dst, src, imm);
325         }
326 
327 }
328 
329 /* Store register on the stack */
330 static inline void emit_store_stack_reg(ptr reg, ptr base,
331                                         unsigned int offset,
332                                         struct jit_ctx *ctx)
333 {
334         emit_long_instr(ctx, SW, reg, offset, base);
335 }
336 
337 static inline void emit_store(ptr reg, ptr base, unsigned int offset,
338                               struct jit_ctx *ctx)
339 {
340         emit_instr(ctx, sw, reg, offset, base);
341 }
342 
343 static inline void emit_load_stack_reg(ptr reg, ptr base,
344                                        unsigned int offset,
345                                        struct jit_ctx *ctx)
346 {
347         emit_long_instr(ctx, LW, reg, offset, base);
348 }
349 
350 static inline void emit_load(unsigned int reg, unsigned int base,
351                              unsigned int offset, struct jit_ctx *ctx)
352 {
353         emit_instr(ctx, lw, reg, offset, base);
354 }
355 
356 static inline void emit_load_byte(unsigned int reg, unsigned int base,
357                                   unsigned int offset, struct jit_ctx *ctx)
358 {
359         emit_instr(ctx, lb, reg, offset, base);
360 }
361 
362 static inline void emit_half_load(unsigned int reg, unsigned int base,
363                                   unsigned int offset, struct jit_ctx *ctx)
364 {
365         emit_instr(ctx, lh, reg, offset, base);
366 }
367 
368 static inline void emit_half_load_unsigned(unsigned int reg, unsigned int base,
369                                            unsigned int offset, struct jit_ctx *ctx)
370 {
371         emit_instr(ctx, lhu, reg, offset, base);
372 }
373 
374 static inline void emit_mul(unsigned int dst, unsigned int src1,
375                             unsigned int src2, struct jit_ctx *ctx)
376 {
377         emit_instr(ctx, mul, dst, src1, src2);
378 }
379 
380 static inline void emit_div(unsigned int dst, unsigned int src,
381                             struct jit_ctx *ctx)
382 {
383         if (ctx->target != NULL) {
384                 u32 *p = &ctx->target[ctx->idx];
385                 uasm_i_divu(&p, dst, src);
386                 p = &ctx->target[ctx->idx + 1];
387                 uasm_i_mflo(&p, dst);
388         }
389         ctx->idx += 2; /* 2 insts */
390 }
391 
392 static inline void emit_mod(unsigned int dst, unsigned int src,
393                             struct jit_ctx *ctx)
394 {
395         if (ctx->target != NULL) {
396                 u32 *p = &ctx->target[ctx->idx];
397                 uasm_i_divu(&p, dst, src);
398                 p = &ctx->target[ctx->idx + 1];
399                 uasm_i_mfhi(&p, dst);
400         }
401         ctx->idx += 2; /* 2 insts */
402 }
403 
404 static inline void emit_dsll(unsigned int dst, unsigned int src,
405                              unsigned int sa, struct jit_ctx *ctx)
406 {
407         emit_instr(ctx, dsll, dst, src, sa);
408 }
409 
410 static inline void emit_dsrl32(unsigned int dst, unsigned int src,
411                                unsigned int sa, struct jit_ctx *ctx)
412 {
413         emit_instr(ctx, dsrl32, dst, src, sa);
414 }
415 
416 static inline void emit_wsbh(unsigned int dst, unsigned int src,
417                              struct jit_ctx *ctx)
418 {
419         emit_instr(ctx, wsbh, dst, src);
420 }
421 
422 /* load pointer to register */
423 static inline void emit_load_ptr(unsigned int dst, unsigned int src,
424                                      int imm, struct jit_ctx *ctx)
425 {
426         /* src contains the base addr of the 32/64-pointer */
427         emit_long_instr(ctx, LW, dst, imm, src);
428 }
429 
430 /* load a function pointer to register */
431 static inline void emit_load_func(unsigned int reg, ptr imm,
432                                   struct jit_ctx *ctx)
433 {
434         if (IS_ENABLED(CONFIG_64BIT)) {
435                 /* At this point imm is always 64-bit */
436                 emit_load_imm(r_tmp, (u64)imm >> 32, ctx);
437                 emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */
438                 emit_ori(r_tmp, r_tmp_imm, (imm >> 16) & 0xffff, ctx);
439                 emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */
440                 emit_ori(reg, r_tmp_imm, imm & 0xffff, ctx);
441         } else {
442                 emit_load_imm(reg, imm, ctx);
443         }
444 }
445 
446 /* Move to real MIPS register */
447 static inline void emit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx)
448 {
449         emit_long_instr(ctx, ADDU, dst, src, r_zero);
450 }
451 
452 /* Move to JIT (32-bit) register */
453 static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx)
454 {
455         emit_addu(dst, src, r_zero, ctx);
456 }
457 
458 /* Compute the immediate value for PC-relative branches. */
459 static inline u32 b_imm(unsigned int tgt, struct jit_ctx *ctx)
460 {
461         if (ctx->target == NULL)
462                 return 0;
463 
464         /*
465          * We want a pc-relative branch. We only do forward branches
466          * so tgt is always after pc. tgt is the instruction offset
467          * we want to jump to.
468 
469          * Branch on MIPS:
470          * I: target_offset <- sign_extend(offset)
471          * I+1: PC += target_offset (delay slot)
472          *
473          * ctx->idx currently points to the branch instruction
474          * but the offset is added to the delay slot so we need
475          * to subtract 4.
476          */
477         return ctx->offsets[tgt] -
478                 (ctx->idx * 4 - ctx->prologue_bytes) - 4;
479 }
480 
481 static inline void emit_bcond(int cond, unsigned int reg1, unsigned int reg2,
482                              unsigned int imm, struct jit_ctx *ctx)
483 {
484         if (ctx->target != NULL) {
485                 u32 *p = &ctx->target[ctx->idx];
486 
487                 switch (cond) {
488                 case MIPS_COND_EQ:
489                         uasm_i_beq(&p, reg1, reg2, imm);
490                         break;
491                 case MIPS_COND_NE:
492                         uasm_i_bne(&p, reg1, reg2, imm);
493                         break;
494                 case MIPS_COND_ALL:
495                         uasm_i_b(&p, imm);
496                         break;
497                 default:
498                         pr_warn("%s: Unhandled branch conditional: %d\n",
499                                 __func__, cond);
500                 }
501         }
502         ctx->idx++;
503 }
504 
505 static inline void emit_b(unsigned int imm, struct jit_ctx *ctx)
506 {
507         emit_bcond(MIPS_COND_ALL, r_zero, r_zero, imm, ctx);
508 }
509 
510 static inline void emit_jalr(unsigned int link, unsigned int reg,
511                              struct jit_ctx *ctx)
512 {
513         emit_instr(ctx, jalr, link, reg);
514 }
515 
516 static inline void emit_jr(unsigned int reg, struct jit_ctx *ctx)
517 {
518         emit_instr(ctx, jr, reg);
519 }
520 
521 static inline u16 align_sp(unsigned int num)
522 {
523         /* Double word alignment for 32-bit, quadword for 64-bit */
524         unsigned int align = IS_ENABLED(CONFIG_64BIT) ? 16 : 8;
525         num = (num + (align - 1)) & -align;
526         return num;
527 }
528 
529 static void save_bpf_jit_regs(struct jit_ctx *ctx, unsigned offset)
530 {
531         int i = 0, real_off = 0;
532         u32 sflags, tmp_flags;
533 
534         /* Adjust the stack pointer */
535         if (offset)
536                 emit_stack_offset(-align_sp(offset), ctx);
537 
538         tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT;
539         /* sflags is essentially a bitmap */
540         while (tmp_flags) {
541                 if ((sflags >> i) & 0x1) {
542                         emit_store_stack_reg(MIPS_R_S0 + i, r_sp, real_off,
543                                              ctx);
544                         real_off += SZREG;
545                 }
546                 i++;
547                 tmp_flags >>= 1;
548         }
549 
550         /* save return address */
551         if (ctx->flags & SEEN_CALL) {
552                 emit_store_stack_reg(r_ra, r_sp, real_off, ctx);
553                 real_off += SZREG;
554         }
555 
556         /* Setup r_M leaving the alignment gap if necessary */
557         if (ctx->flags & SEEN_MEM) {
558                 if (real_off % (SZREG * 2))
559                         real_off += SZREG;
560                 emit_long_instr(ctx, ADDIU, r_M, r_sp, real_off);
561         }
562 }
563 
564 static void restore_bpf_jit_regs(struct jit_ctx *ctx,
565                                  unsigned int offset)
566 {
567         int i, real_off = 0;
568         u32 sflags, tmp_flags;
569 
570         tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT;
571         /* sflags is a bitmap */
572         i = 0;
573         while (tmp_flags) {
574                 if ((sflags >> i) & 0x1) {
575                         emit_load_stack_reg(MIPS_R_S0 + i, r_sp, real_off,
576                                             ctx);
577                         real_off += SZREG;
578                 }
579                 i++;
580                 tmp_flags >>= 1;
581         }
582 
583         /* restore return address */
584         if (ctx->flags & SEEN_CALL)
585                 emit_load_stack_reg(r_ra, r_sp, real_off, ctx);
586 
587         /* Restore the sp and discard the scrach memory */
588         if (offset)
589                 emit_stack_offset(align_sp(offset), ctx);
590 }
591 
592 static unsigned int get_stack_depth(struct jit_ctx *ctx)
593 {
594         int sp_off = 0;
595 
596 
597         /* How may s* regs do we need to preserved? */
598         sp_off += hweight32(ctx->flags >> SEEN_SREG_SFT) * SZREG;
599 
600         if (ctx->flags & SEEN_MEM)
601                 sp_off += 4 * BPF_MEMWORDS; /* BPF_MEMWORDS are 32-bit */
602 
603         if (ctx->flags & SEEN_CALL)
604                 sp_off += SZREG; /* Space for our ra register */
605 
606         return sp_off;
607 }
608 
609 static void build_prologue(struct jit_ctx *ctx)
610 {
611         int sp_off;
612 
613         /* Calculate the total offset for the stack pointer */
614         sp_off = get_stack_depth(ctx);
615         save_bpf_jit_regs(ctx, sp_off);
616 
617         if (ctx->flags & SEEN_SKB)
618                 emit_reg_move(r_skb, MIPS_R_A0, ctx);
619 
620         if (ctx->flags & SEEN_SKB_DATA) {
621                 /* Load packet length */
622                 emit_load(r_skb_len, r_skb, offsetof(struct sk_buff, len),
623                           ctx);
624                 emit_load(r_tmp, r_skb, offsetof(struct sk_buff, data_len),
625                           ctx);
626                 /* Load the data pointer */
627                 emit_load_ptr(r_skb_data, r_skb,
628                               offsetof(struct sk_buff, data), ctx);
629                 /* Load the header length */
630                 emit_subu(r_skb_hl, r_skb_len, r_tmp, ctx);
631         }
632 
633         if (ctx->flags & SEEN_X)
634                 emit_jit_reg_move(r_X, r_zero, ctx);
635 
636         /*
637          * Do not leak kernel data to userspace, we only need to clear
638          * r_A if it is ever used.  In fact if it is never used, we
639          * will not save/restore it, so clearing it in this case would
640          * corrupt the state of the caller.
641          */
642         if (bpf_needs_clear_a(&ctx->skf->insns[0]) &&
643             (ctx->flags & SEEN_A))
644                 emit_jit_reg_move(r_A, r_zero, ctx);
645 }
646 
647 static void build_epilogue(struct jit_ctx *ctx)
648 {
649         unsigned int sp_off;
650 
651         /* Calculate the total offset for the stack pointer */
652 
653         sp_off = get_stack_depth(ctx);
654         restore_bpf_jit_regs(ctx, sp_off);
655 
656         /* Return */
657         emit_jr(r_ra, ctx);
658         emit_nop(ctx);
659 }
660 
661 #define CHOOSE_LOAD_FUNC(K, func) \
662         ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative : func) : \
663          func##_positive)
664 
665 static int build_body(struct jit_ctx *ctx)
666 {
667         const struct bpf_prog *prog = ctx->skf;
668         const struct sock_filter *inst;
669         unsigned int i, off, condt;
670         u32 k, b_off __maybe_unused;
671         u8 (*sk_load_func)(unsigned long *skb, int offset);
672 
673         for (i = 0; i < prog->len; i++) {
674                 u16 code;
675 
676                 inst = &(prog->insns[i]);
677                 pr_debug("%s: code->0x%02x, jt->0x%x, jf->0x%x, k->0x%x\n",
678                          __func__, inst->code, inst->jt, inst->jf, inst->k);
679                 k = inst->k;
680                 code = bpf_anc_helper(inst);
681 
682                 if (ctx->target == NULL)
683                         ctx->offsets[i] = ctx->idx * 4;
684 
685                 switch (code) {
686                 case BPF_LD | BPF_IMM:
687                         /* A <- k ==> li r_A, k */
688                         ctx->flags |= SEEN_A;
689                         emit_load_imm(r_A, k, ctx);
690                         break;
691                 case BPF_LD | BPF_W | BPF_LEN:
692                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
693                         /* A <- len ==> lw r_A, offset(skb) */
694                         ctx->flags |= SEEN_SKB | SEEN_A;
695                         off = offsetof(struct sk_buff, len);
696                         emit_load(r_A, r_skb, off, ctx);
697                         break;
698                 case BPF_LD | BPF_MEM:
699                         /* A <- M[k] ==> lw r_A, offset(M) */
700                         ctx->flags |= SEEN_MEM | SEEN_A;
701                         emit_load(r_A, r_M, SCRATCH_OFF(k), ctx);
702                         break;
703                 case BPF_LD | BPF_W | BPF_ABS:
704                         /* A <- P[k:4] */
705                         sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_word);
706                         goto load;
707                 case BPF_LD | BPF_H | BPF_ABS:
708                         /* A <- P[k:2] */
709                         sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_half);
710                         goto load;
711                 case BPF_LD | BPF_B | BPF_ABS:
712                         /* A <- P[k:1] */
713                         sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_byte);
714 load:
715                         emit_load_imm(r_off, k, ctx);
716 load_common:
717                         ctx->flags |= SEEN_CALL | SEEN_OFF |
718                                 SEEN_SKB | SEEN_A | SEEN_SKB_DATA;
719 
720                         emit_load_func(r_s0, (ptr)sk_load_func, ctx);
721                         emit_reg_move(MIPS_R_A0, r_skb, ctx);
722                         emit_jalr(MIPS_R_RA, r_s0, ctx);
723                         /* Load second argument to delay slot */
724                         emit_reg_move(MIPS_R_A1, r_off, ctx);
725                         /* Check the error value */
726                         emit_bcond(MIPS_COND_EQ, r_ret, 0, b_imm(i + 1, ctx),
727                                    ctx);
728                         /* Load return register on DS for failures */
729                         emit_reg_move(r_ret, r_zero, ctx);
730                         /* Return with error */
731                         emit_b(b_imm(prog->len, ctx), ctx);
732                         emit_nop(ctx);
733                         break;
734                 case BPF_LD | BPF_W | BPF_IND:
735                         /* A <- P[X + k:4] */
736                         sk_load_func = sk_load_word;
737                         goto load_ind;
738                 case BPF_LD | BPF_H | BPF_IND:
739                         /* A <- P[X + k:2] */
740                         sk_load_func = sk_load_half;
741                         goto load_ind;
742                 case BPF_LD | BPF_B | BPF_IND:
743                         /* A <- P[X + k:1] */
744                         sk_load_func = sk_load_byte;
745 load_ind:
746                         ctx->flags |= SEEN_OFF | SEEN_X;
747                         emit_addiu(r_off, r_X, k, ctx);
748                         goto load_common;
749                 case BPF_LDX | BPF_IMM:
750                         /* X <- k */
751                         ctx->flags |= SEEN_X;
752                         emit_load_imm(r_X, k, ctx);
753                         break;
754                 case BPF_LDX | BPF_MEM:
755                         /* X <- M[k] */
756                         ctx->flags |= SEEN_X | SEEN_MEM;
757                         emit_load(r_X, r_M, SCRATCH_OFF(k), ctx);
758                         break;
759                 case BPF_LDX | BPF_W | BPF_LEN:
760                         /* X <- len */
761                         ctx->flags |= SEEN_X | SEEN_SKB;
762                         off = offsetof(struct sk_buff, len);
763                         emit_load(r_X, r_skb, off, ctx);
764                         break;
765                 case BPF_LDX | BPF_B | BPF_MSH:
766                         /* X <- 4 * (P[k:1] & 0xf) */
767                         ctx->flags |= SEEN_X | SEEN_CALL | SEEN_SKB;
768                         /* Load offset to a1 */
769                         emit_load_func(r_s0, (ptr)sk_load_byte, ctx);
770                         /*
771                          * This may emit two instructions so it may not fit
772                          * in the delay slot. So use a0 in the delay slot.
773                          */
774                         emit_load_imm(MIPS_R_A1, k, ctx);
775                         emit_jalr(MIPS_R_RA, r_s0, ctx);
776                         emit_reg_move(MIPS_R_A0, r_skb, ctx); /* delay slot */
777                         /* Check the error value */
778                         emit_bcond(MIPS_COND_NE, r_ret, 0,
779                                    b_imm(prog->len, ctx), ctx);
780                         emit_reg_move(r_ret, r_zero, ctx);
781                         /* We are good */
782                         /* X <- P[1:K] & 0xf */
783                         emit_andi(r_X, r_A, 0xf, ctx);
784                         /* X << 2 */
785                         emit_b(b_imm(i + 1, ctx), ctx);
786                         emit_sll(r_X, r_X, 2, ctx); /* delay slot */
787                         break;
788                 case BPF_ST:
789                         /* M[k] <- A */
790                         ctx->flags |= SEEN_MEM | SEEN_A;
791                         emit_store(r_A, r_M, SCRATCH_OFF(k), ctx);
792                         break;
793                 case BPF_STX:
794                         /* M[k] <- X */
795                         ctx->flags |= SEEN_MEM | SEEN_X;
796                         emit_store(r_X, r_M, SCRATCH_OFF(k), ctx);
797                         break;
798                 case BPF_ALU | BPF_ADD | BPF_K:
799                         /* A += K */
800                         ctx->flags |= SEEN_A;
801                         emit_addiu(r_A, r_A, k, ctx);
802                         break;
803                 case BPF_ALU | BPF_ADD | BPF_X:
804                         /* A += X */
805                         ctx->flags |= SEEN_A | SEEN_X;
806                         emit_addu(r_A, r_A, r_X, ctx);
807                         break;
808                 case BPF_ALU | BPF_SUB | BPF_K:
809                         /* A -= K */
810                         ctx->flags |= SEEN_A;
811                         emit_addiu(r_A, r_A, -k, ctx);
812                         break;
813                 case BPF_ALU | BPF_SUB | BPF_X:
814                         /* A -= X */
815                         ctx->flags |= SEEN_A | SEEN_X;
816                         emit_subu(r_A, r_A, r_X, ctx);
817                         break;
818                 case BPF_ALU | BPF_MUL | BPF_K:
819                         /* A *= K */
820                         /* Load K to scratch register before MUL */
821                         ctx->flags |= SEEN_A;
822                         emit_load_imm(r_s0, k, ctx);
823                         emit_mul(r_A, r_A, r_s0, ctx);
824                         break;
825                 case BPF_ALU | BPF_MUL | BPF_X:
826                         /* A *= X */
827                         ctx->flags |= SEEN_A | SEEN_X;
828                         emit_mul(r_A, r_A, r_X, ctx);
829                         break;
830                 case BPF_ALU | BPF_DIV | BPF_K:
831                         /* A /= k */
832                         if (k == 1)
833                                 break;
834                         if (optimize_div(&k)) {
835                                 ctx->flags |= SEEN_A;
836                                 emit_srl(r_A, r_A, k, ctx);
837                                 break;
838                         }
839                         ctx->flags |= SEEN_A;
840                         emit_load_imm(r_s0, k, ctx);
841                         emit_div(r_A, r_s0, ctx);
842                         break;
843                 case BPF_ALU | BPF_MOD | BPF_K:
844                         /* A %= k */
845                         if (k == 1) {
846                                 ctx->flags |= SEEN_A;
847                                 emit_jit_reg_move(r_A, r_zero, ctx);
848                         } else {
849                                 ctx->flags |= SEEN_A;
850                                 emit_load_imm(r_s0, k, ctx);
851                                 emit_mod(r_A, r_s0, ctx);
852                         }
853                         break;
854                 case BPF_ALU | BPF_DIV | BPF_X:
855                         /* A /= X */
856                         ctx->flags |= SEEN_X | SEEN_A;
857                         /* Check if r_X is zero */
858                         emit_bcond(MIPS_COND_EQ, r_X, r_zero,
859                                    b_imm(prog->len, ctx), ctx);
860                         emit_load_imm(r_ret, 0, ctx); /* delay slot */
861                         emit_div(r_A, r_X, ctx);
862                         break;
863                 case BPF_ALU | BPF_MOD | BPF_X:
864                         /* A %= X */
865                         ctx->flags |= SEEN_X | SEEN_A;
866                         /* Check if r_X is zero */
867                         emit_bcond(MIPS_COND_EQ, r_X, r_zero,
868                                    b_imm(prog->len, ctx), ctx);
869                         emit_load_imm(r_ret, 0, ctx); /* delay slot */
870                         emit_mod(r_A, r_X, ctx);
871                         break;
872                 case BPF_ALU | BPF_OR | BPF_K:
873                         /* A |= K */
874                         ctx->flags |= SEEN_A;
875                         emit_ori(r_A, r_A, k, ctx);
876                         break;
877                 case BPF_ALU | BPF_OR | BPF_X:
878                         /* A |= X */
879                         ctx->flags |= SEEN_A;
880                         emit_ori(r_A, r_A, r_X, ctx);
881                         break;
882                 case BPF_ALU | BPF_XOR | BPF_K:
883                         /* A ^= k */
884                         ctx->flags |= SEEN_A;
885                         emit_xori(r_A, r_A, k, ctx);
886                         break;
887                 case BPF_ANC | SKF_AD_ALU_XOR_X:
888                 case BPF_ALU | BPF_XOR | BPF_X:
889                         /* A ^= X */
890                         ctx->flags |= SEEN_A;
891                         emit_xor(r_A, r_A, r_X, ctx);
892                         break;
893                 case BPF_ALU | BPF_AND | BPF_K:
894                         /* A &= K */
895                         ctx->flags |= SEEN_A;
896                         emit_andi(r_A, r_A, k, ctx);
897                         break;
898                 case BPF_ALU | BPF_AND | BPF_X:
899                         /* A &= X */
900                         ctx->flags |= SEEN_A | SEEN_X;
901                         emit_and(r_A, r_A, r_X, ctx);
902                         break;
903                 case BPF_ALU | BPF_LSH | BPF_K:
904                         /* A <<= K */
905                         ctx->flags |= SEEN_A;
906                         emit_sll(r_A, r_A, k, ctx);
907                         break;
908                 case BPF_ALU | BPF_LSH | BPF_X:
909                         /* A <<= X */
910                         ctx->flags |= SEEN_A | SEEN_X;
911                         emit_sllv(r_A, r_A, r_X, ctx);
912                         break;
913                 case BPF_ALU | BPF_RSH | BPF_K:
914                         /* A >>= K */
915                         ctx->flags |= SEEN_A;
916                         emit_srl(r_A, r_A, k, ctx);
917                         break;
918                 case BPF_ALU | BPF_RSH | BPF_X:
919                         ctx->flags |= SEEN_A | SEEN_X;
920                         emit_srlv(r_A, r_A, r_X, ctx);
921                         break;
922                 case BPF_ALU | BPF_NEG:
923                         /* A = -A */
924                         ctx->flags |= SEEN_A;
925                         emit_neg(r_A, ctx);
926                         break;
927                 case BPF_JMP | BPF_JA:
928                         /* pc += K */
929                         emit_b(b_imm(i + k + 1, ctx), ctx);
930                         emit_nop(ctx);
931                         break;
932                 case BPF_JMP | BPF_JEQ | BPF_K:
933                         /* pc += ( A == K ) ? pc->jt : pc->jf */
934                         condt = MIPS_COND_EQ | MIPS_COND_K;
935                         goto jmp_cmp;
936                 case BPF_JMP | BPF_JEQ | BPF_X:
937                         ctx->flags |= SEEN_X;
938                         /* pc += ( A == X ) ? pc->jt : pc->jf */
939                         condt = MIPS_COND_EQ | MIPS_COND_X;
940                         goto jmp_cmp;
941                 case BPF_JMP | BPF_JGE | BPF_K:
942                         /* pc += ( A >= K ) ? pc->jt : pc->jf */
943                         condt = MIPS_COND_GE | MIPS_COND_K;
944                         goto jmp_cmp;
945                 case BPF_JMP | BPF_JGE | BPF_X:
946                         ctx->flags |= SEEN_X;
947                         /* pc += ( A >= X ) ? pc->jt : pc->jf */
948                         condt = MIPS_COND_GE | MIPS_COND_X;
949                         goto jmp_cmp;
950                 case BPF_JMP | BPF_JGT | BPF_K:
951                         /* pc += ( A > K ) ? pc->jt : pc->jf */
952                         condt = MIPS_COND_GT | MIPS_COND_K;
953                         goto jmp_cmp;
954                 case BPF_JMP | BPF_JGT | BPF_X:
955                         ctx->flags |= SEEN_X;
956                         /* pc += ( A > X ) ? pc->jt : pc->jf */
957                         condt = MIPS_COND_GT | MIPS_COND_X;
958 jmp_cmp:
959                         /* Greater or Equal */
960                         if ((condt & MIPS_COND_GE) ||
961                             (condt & MIPS_COND_GT)) {
962                                 if (condt & MIPS_COND_K) { /* K */
963                                         ctx->flags |= SEEN_A;
964                                         emit_sltiu(r_s0, r_A, k, ctx);
965                                 } else { /* X */
966                                         ctx->flags |= SEEN_A |
967                                                 SEEN_X;
968                                         emit_sltu(r_s0, r_A, r_X, ctx);
969                                 }
970                                 /* A < (K|X) ? r_scrach = 1 */
971                                 b_off = b_imm(i + inst->jf + 1, ctx);
972                                 emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off,
973                                            ctx);
974                                 emit_nop(ctx);
975                                 /* A > (K|X) ? scratch = 0 */
976                                 if (condt & MIPS_COND_GT) {
977                                         /* Checking for equality */
978                                         ctx->flags |= SEEN_A | SEEN_X;
979                                         if (condt & MIPS_COND_K)
980                                                 emit_load_imm(r_s0, k, ctx);
981                                         else
982                                                 emit_jit_reg_move(r_s0, r_X,
983                                                                   ctx);
984                                         b_off = b_imm(i + inst->jf + 1, ctx);
985                                         emit_bcond(MIPS_COND_EQ, r_A, r_s0,
986                                                    b_off, ctx);
987                                         emit_nop(ctx);
988                                         /* Finally, A > K|X */
989                                         b_off = b_imm(i + inst->jt + 1, ctx);
990                                         emit_b(b_off, ctx);
991                                         emit_nop(ctx);
992                                 } else {
993                                         /* A >= (K|X) so jump */
994                                         b_off = b_imm(i + inst->jt + 1, ctx);
995                                         emit_b(b_off, ctx);
996                                         emit_nop(ctx);
997                                 }
998                         } else {
999                                 /* A == K|X */
1000                                 if (condt & MIPS_COND_K) { /* K */
1001                                         ctx->flags |= SEEN_A;
1002                                         emit_load_imm(r_s0, k, ctx);
1003                                         /* jump true */
1004                                         b_off = b_imm(i + inst->jt + 1, ctx);
1005                                         emit_bcond(MIPS_COND_EQ, r_A, r_s0,
1006                                                    b_off, ctx);
1007                                         emit_nop(ctx);
1008                                         /* jump false */
1009                                         b_off = b_imm(i + inst->jf + 1,
1010                                                       ctx);
1011                                         emit_bcond(MIPS_COND_NE, r_A, r_s0,
1012                                                    b_off, ctx);
1013                                         emit_nop(ctx);
1014                                 } else { /* X */
1015                                         /* jump true */
1016                                         ctx->flags |= SEEN_A | SEEN_X;
1017                                         b_off = b_imm(i + inst->jt + 1,
1018                                                       ctx);
1019                                         emit_bcond(MIPS_COND_EQ, r_A, r_X,
1020                                                    b_off, ctx);
1021                                         emit_nop(ctx);
1022                                         /* jump false */
1023                                         b_off = b_imm(i + inst->jf + 1, ctx);
1024                                         emit_bcond(MIPS_COND_NE, r_A, r_X,
1025                                                    b_off, ctx);
1026                                         emit_nop(ctx);
1027                                 }
1028                         }
1029                         break;
1030                 case BPF_JMP | BPF_JSET | BPF_K:
1031                         ctx->flags |= SEEN_A;
1032                         /* pc += (A & K) ? pc -> jt : pc -> jf */
1033                         emit_load_imm(r_s1, k, ctx);
1034                         emit_and(r_s0, r_A, r_s1, ctx);
1035                         /* jump true */
1036                         b_off = b_imm(i + inst->jt + 1, ctx);
1037                         emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx);
1038                         emit_nop(ctx);
1039                         /* jump false */
1040                         b_off = b_imm(i + inst->jf + 1, ctx);
1041                         emit_b(b_off, ctx);
1042                         emit_nop(ctx);
1043                         break;
1044                 case BPF_JMP | BPF_JSET | BPF_X:
1045                         ctx->flags |= SEEN_X | SEEN_A;
1046                         /* pc += (A & X) ? pc -> jt : pc -> jf */
1047                         emit_and(r_s0, r_A, r_X, ctx);
1048                         /* jump true */
1049                         b_off = b_imm(i + inst->jt + 1, ctx);
1050                         emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx);
1051                         emit_nop(ctx);
1052                         /* jump false */
1053                         b_off = b_imm(i + inst->jf + 1, ctx);
1054                         emit_b(b_off, ctx);
1055                         emit_nop(ctx);
1056                         break;
1057                 case BPF_RET | BPF_A:
1058                         ctx->flags |= SEEN_A;
1059                         if (i != prog->len - 1)
1060                                 /*
1061                                  * If this is not the last instruction
1062                                  * then jump to the epilogue
1063                                  */
1064                                 emit_b(b_imm(prog->len, ctx), ctx);
1065                         emit_reg_move(r_ret, r_A, ctx); /* delay slot */
1066                         break;
1067                 case BPF_RET | BPF_K:
1068                         /*
1069                          * It can emit two instructions so it does not fit on
1070                          * the delay slot.
1071                          */
1072                         emit_load_imm(r_ret, k, ctx);
1073                         if (i != prog->len - 1) {
1074                                 /*
1075                                  * If this is not the last instruction
1076                                  * then jump to the epilogue
1077                                  */
1078                                 emit_b(b_imm(prog->len, ctx), ctx);
1079                                 emit_nop(ctx);
1080                         }
1081                         break;
1082                 case BPF_MISC | BPF_TAX:
1083                         /* X = A */
1084                         ctx->flags |= SEEN_X | SEEN_A;
1085                         emit_jit_reg_move(r_X, r_A, ctx);
1086                         break;
1087                 case BPF_MISC | BPF_TXA:
1088                         /* A = X */
1089                         ctx->flags |= SEEN_A | SEEN_X;
1090                         emit_jit_reg_move(r_A, r_X, ctx);
1091                         break;
1092                 /* AUX */
1093                 case BPF_ANC | SKF_AD_PROTOCOL:
1094                         /* A = ntohs(skb->protocol */
1095                         ctx->flags |= SEEN_SKB | SEEN_OFF | SEEN_A;
1096                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1097                                                   protocol) != 2);
1098                         off = offsetof(struct sk_buff, protocol);
1099                         emit_half_load(r_A, r_skb, off, ctx);
1100 #ifdef CONFIG_CPU_LITTLE_ENDIAN
1101                         /* This needs little endian fixup */
1102                         if (cpu_has_wsbh) {
1103                                 /* R2 and later have the wsbh instruction */
1104                                 emit_wsbh(r_A, r_A, ctx);
1105                         } else {
1106                                 /* Get first byte */
1107                                 emit_andi(r_tmp_imm, r_A, 0xff, ctx);
1108                                 /* Shift it */
1109                                 emit_sll(r_tmp, r_tmp_imm, 8, ctx);
1110                                 /* Get second byte */
1111                                 emit_srl(r_tmp_imm, r_A, 8, ctx);
1112                                 emit_andi(r_tmp_imm, r_tmp_imm, 0xff, ctx);
1113                                 /* Put everyting together in r_A */
1114                                 emit_or(r_A, r_tmp, r_tmp_imm, ctx);
1115                         }
1116 #endif
1117                         break;
1118                 case BPF_ANC | SKF_AD_CPU:
1119                         ctx->flags |= SEEN_A | SEEN_OFF;
1120                         /* A = current_thread_info()->cpu */
1121                         BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info,
1122                                                   cpu) != 4);
1123                         off = offsetof(struct thread_info, cpu);
1124                         /* $28/gp points to the thread_info struct */
1125                         emit_load(r_A, 28, off, ctx);
1126                         break;
1127                 case BPF_ANC | SKF_AD_IFINDEX:
1128                         /* A = skb->dev->ifindex */
1129                 case BPF_ANC | SKF_AD_HATYPE:
1130                         /* A = skb->dev->type */
1131                         ctx->flags |= SEEN_SKB | SEEN_A;
1132                         off = offsetof(struct sk_buff, dev);
1133                         /* Load *dev pointer */
1134                         emit_load_ptr(r_s0, r_skb, off, ctx);
1135                         /* error (0) in the delay slot */
1136                         emit_bcond(MIPS_COND_EQ, r_s0, r_zero,
1137                                    b_imm(prog->len, ctx), ctx);
1138                         emit_reg_move(r_ret, r_zero, ctx);
1139                         if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
1140                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
1141                                 off = offsetof(struct net_device, ifindex);
1142                                 emit_load(r_A, r_s0, off, ctx);
1143                         } else { /* (code == (BPF_ANC | SKF_AD_HATYPE) */
1144                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
1145                                 off = offsetof(struct net_device, type);
1146                                 emit_half_load_unsigned(r_A, r_s0, off, ctx);
1147                         }
1148                         break;
1149                 case BPF_ANC | SKF_AD_MARK:
1150                         ctx->flags |= SEEN_SKB | SEEN_A;
1151                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
1152                         off = offsetof(struct sk_buff, mark);
1153                         emit_load(r_A, r_skb, off, ctx);
1154                         break;
1155                 case BPF_ANC | SKF_AD_RXHASH:
1156                         ctx->flags |= SEEN_SKB | SEEN_A;
1157                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
1158                         off = offsetof(struct sk_buff, hash);
1159                         emit_load(r_A, r_skb, off, ctx);
1160                         break;
1161                 case BPF_ANC | SKF_AD_VLAN_TAG:
1162                 case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
1163                         ctx->flags |= SEEN_SKB | SEEN_A;
1164                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1165                                                   vlan_tci) != 2);
1166                         off = offsetof(struct sk_buff, vlan_tci);
1167                         emit_half_load_unsigned(r_s0, r_skb, off, ctx);
1168                         if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
1169                                 emit_andi(r_A, r_s0, (u16)~VLAN_TAG_PRESENT, ctx);
1170                         } else {
1171                                 emit_andi(r_A, r_s0, VLAN_TAG_PRESENT, ctx);
1172                                 /* return 1 if present */
1173                                 emit_sltu(r_A, r_zero, r_A, ctx);
1174                         }
1175                         break;
1176                 case BPF_ANC | SKF_AD_PKTTYPE:
1177                         ctx->flags |= SEEN_SKB;
1178 
1179                         emit_load_byte(r_tmp, r_skb, PKT_TYPE_OFFSET(), ctx);
1180                         /* Keep only the last 3 bits */
1181                         emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
1182 #ifdef __BIG_ENDIAN_BITFIELD
1183                         /* Get the actual packet type to the lower 3 bits */
1184                         emit_srl(r_A, r_A, 5, ctx);
1185 #endif
1186                         break;
1187                 case BPF_ANC | SKF_AD_QUEUE:
1188                         ctx->flags |= SEEN_SKB | SEEN_A;
1189                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
1190                                                   queue_mapping) != 2);
1191                         BUILD_BUG_ON(offsetof(struct sk_buff,
1192                                               queue_mapping) > 0xff);
1193                         off = offsetof(struct sk_buff, queue_mapping);
1194                         emit_half_load_unsigned(r_A, r_skb, off, ctx);
1195                         break;
1196                 default:
1197                         pr_debug("%s: Unhandled opcode: 0x%02x\n", __FILE__,
1198                                  inst->code);
1199                         return -1;
1200                 }
1201         }
1202 
1203         /* compute offsets only during the first pass */
1204         if (ctx->target == NULL)
1205                 ctx->offsets[i] = ctx->idx * 4;
1206 
1207         return 0;
1208 }
1209 
1210 void bpf_jit_compile(struct bpf_prog *fp)
1211 {
1212         struct jit_ctx ctx;
1213         unsigned int alloc_size, tmp_idx;
1214 
1215         if (!bpf_jit_enable)
1216                 return;
1217 
1218         memset(&ctx, 0, sizeof(ctx));
1219 
1220         ctx.offsets = kcalloc(fp->len + 1, sizeof(*ctx.offsets), GFP_KERNEL);
1221         if (ctx.offsets == NULL)
1222                 return;
1223 
1224         ctx.skf = fp;
1225 
1226         if (build_body(&ctx))
1227                 goto out;
1228 
1229         tmp_idx = ctx.idx;
1230         build_prologue(&ctx);
1231         ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
1232         /* just to complete the ctx.idx count */
1233         build_epilogue(&ctx);
1234 
1235         alloc_size = 4 * ctx.idx;
1236         ctx.target = module_alloc(alloc_size);
1237         if (ctx.target == NULL)
1238                 goto out;
1239 
1240         /* Clean it */
1241         memset(ctx.target, 0, alloc_size);
1242 
1243         ctx.idx = 0;
1244 
1245         /* Generate the actual JIT code */
1246         build_prologue(&ctx);
1247         build_body(&ctx);
1248         build_epilogue(&ctx);
1249 
1250         /* Update the icache */
1251         flush_icache_range((ptr)ctx.target, (ptr)(ctx.target + ctx.idx));
1252 
1253         if (bpf_jit_enable > 1)
1254                 /* Dump JIT code */
1255                 bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
1256 
1257         fp->bpf_func = (void *)ctx.target;
1258         fp->jited = 1;
1259 
1260 out:
1261         kfree(ctx.offsets);
1262 }
1263 
1264 void bpf_jit_free(struct bpf_prog *fp)
1265 {
1266         if (fp->jited)
1267                 module_memfree(fp->bpf_func);
1268 
1269         bpf_prog_unlock_free(fp);
1270 }
1271 

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