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1/*
2 * Just-In-Time compiler for BPF filters on 32bit ARM
3 *
4 * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; version 2 of the License.
9 */
10
11#include <linux/bitops.h>
12#include <linux/compiler.h>
13#include <linux/errno.h>
14#include <linux/filter.h>
15#include <linux/netdevice.h>
16#include <linux/string.h>
17#include <linux/slab.h>
18#include <linux/if_vlan.h>
19
20#include <asm/cacheflush.h>
21#include <asm/hwcap.h>
22#include <asm/opcodes.h>
23
24#include "bpf_jit_32.h"
25
26/*
27 * ABI:
28 *
29 * r0 scratch register
30 * r4 BPF register A
31 * r5 BPF register X
32 * r6 pointer to the skb
33 * r7 skb->data
34 * r8 skb_headlen(skb)
35 */
36
37#define r_scratch ARM_R0
38/* r1-r3 are (also) used for the unaligned loads on the non-ARMv7 slowpath */
39#define r_off ARM_R1
40#define r_A ARM_R4
41#define r_X ARM_R5
42#define r_skb ARM_R6
43#define r_skb_data ARM_R7
44#define r_skb_hl ARM_R8
45
46#define SCRATCH_SP_OFFSET 0
47#define SCRATCH_OFF(k) (SCRATCH_SP_OFFSET + 4 * (k))
48
49#define SEEN_MEM ((1 << BPF_MEMWORDS) - 1)
50#define SEEN_MEM_WORD(k) (1 << (k))
51#define SEEN_X (1 << BPF_MEMWORDS)
52#define SEEN_CALL (1 << (BPF_MEMWORDS + 1))
53#define SEEN_SKB (1 << (BPF_MEMWORDS + 2))
54#define SEEN_DATA (1 << (BPF_MEMWORDS + 3))
55
56#define FLAG_NEED_X_RESET (1 << 0)
57#define FLAG_IMM_OVERFLOW (1 << 1)
58
59struct jit_ctx {
60 const struct bpf_prog *skf;
61 unsigned idx;
62 unsigned prologue_bytes;
63 int ret0_fp_idx;
64 u32 seen;
65 u32 flags;
66 u32 *offsets;
67 u32 *target;
68#if __LINUX_ARM_ARCH__ < 7
69 u16 epilogue_bytes;
70 u16 imm_count;
71 u32 *imms;
72#endif
73};
74
75int bpf_jit_enable __read_mostly;
76
77static inline int call_neg_helper(struct sk_buff *skb, int offset, void *ret,
78 unsigned int size)
79{
80 void *ptr = bpf_internal_load_pointer_neg_helper(skb, offset, size);
81
82 if (!ptr)
83 return -EFAULT;
84 memcpy(ret, ptr, size);
85 return 0;
86}
87
88static u64 jit_get_skb_b(struct sk_buff *skb, int offset)
89{
90 u8 ret;
91 int err;
92
93 if (offset < 0)
94 err = call_neg_helper(skb, offset, &ret, 1);
95 else
96 err = skb_copy_bits(skb, offset, &ret, 1);
97
98 return (u64)err << 32 | ret;
99}
100
101static u64 jit_get_skb_h(struct sk_buff *skb, int offset)
102{
103 u16 ret;
104 int err;
105
106 if (offset < 0)
107 err = call_neg_helper(skb, offset, &ret, 2);
108 else
109 err = skb_copy_bits(skb, offset, &ret, 2);
110
111 return (u64)err << 32 | ntohs(ret);
112}
113
114static u64 jit_get_skb_w(struct sk_buff *skb, int offset)
115{
116 u32 ret;
117 int err;
118
119 if (offset < 0)
120 err = call_neg_helper(skb, offset, &ret, 4);
121 else
122 err = skb_copy_bits(skb, offset, &ret, 4);
123
124 return (u64)err << 32 | ntohl(ret);
125}
126
127/*
128 * Wrappers which handle both OABI and EABI and assures Thumb2 interworking
129 * (where the assembly routines like __aeabi_uidiv could cause problems).
130 */
131static u32 jit_udiv(u32 dividend, u32 divisor)
132{
133 return dividend / divisor;
134}
135
136static u32 jit_mod(u32 dividend, u32 divisor)
137{
138 return dividend % divisor;
139}
140
141static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx)
142{
143 inst |= (cond << 28);
144 inst = __opcode_to_mem_arm(inst);
145
146 if (ctx->target != NULL)
147 ctx->target[ctx->idx] = inst;
148
149 ctx->idx++;
150}
151
152/*
153 * Emit an instruction that will be executed unconditionally.
154 */
155static inline void emit(u32 inst, struct jit_ctx *ctx)
156{
157 _emit(ARM_COND_AL, inst, ctx);
158}
159
160static u16 saved_regs(struct jit_ctx *ctx)
161{
162 u16 ret = 0;
163
164 if ((ctx->skf->len > 1) ||
165 (ctx->skf->insns[0].code == (BPF_RET | BPF_A)))
166 ret |= 1 << r_A;
167
168#ifdef CONFIG_FRAME_POINTER
169 ret |= (1 << ARM_FP) | (1 << ARM_IP) | (1 << ARM_LR) | (1 << ARM_PC);
170#else
171 if (ctx->seen & SEEN_CALL)
172 ret |= 1 << ARM_LR;
173#endif
174 if (ctx->seen & (SEEN_DATA | SEEN_SKB))
175 ret |= 1 << r_skb;
176 if (ctx->seen & SEEN_DATA)
177 ret |= (1 << r_skb_data) | (1 << r_skb_hl);
178 if (ctx->seen & SEEN_X)
179 ret |= 1 << r_X;
180
181 return ret;
182}
183
184static inline int mem_words_used(struct jit_ctx *ctx)
185{
186 /* yes, we do waste some stack space IF there are "holes" in the set" */
187 return fls(ctx->seen & SEEN_MEM);
188}
189
190static void jit_fill_hole(void *area, unsigned int size)
191{
192 u32 *ptr;
193 /* We are guaranteed to have aligned memory. */
194 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
195 *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF);
196}
197
198static void build_prologue(struct jit_ctx *ctx)
199{
200 u16 reg_set = saved_regs(ctx);
201 u16 off;
202
203#ifdef CONFIG_FRAME_POINTER
204 emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx);
205 emit(ARM_PUSH(reg_set), ctx);
206 emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx);
207#else
208 if (reg_set)
209 emit(ARM_PUSH(reg_set), ctx);
210#endif
211
212 if (ctx->seen & (SEEN_DATA | SEEN_SKB))
213 emit(ARM_MOV_R(r_skb, ARM_R0), ctx);
214
215 if (ctx->seen & SEEN_DATA) {
216 off = offsetof(struct sk_buff, data);
217 emit(ARM_LDR_I(r_skb_data, r_skb, off), ctx);
218 /* headlen = len - data_len */
219 off = offsetof(struct sk_buff, len);
220 emit(ARM_LDR_I(r_skb_hl, r_skb, off), ctx);
221 off = offsetof(struct sk_buff, data_len);
222 emit(ARM_LDR_I(r_scratch, r_skb, off), ctx);
223 emit(ARM_SUB_R(r_skb_hl, r_skb_hl, r_scratch), ctx);
224 }
225
226 if (ctx->flags & FLAG_NEED_X_RESET)
227 emit(ARM_MOV_I(r_X, 0), ctx);
228
229 /* do not leak kernel data to userspace */
230 if (bpf_needs_clear_a(&ctx->skf->insns[0]))
231 emit(ARM_MOV_I(r_A, 0), ctx);
232
233 /* stack space for the BPF_MEM words */
234 if (ctx->seen & SEEN_MEM)
235 emit(ARM_SUB_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx);
236}
237
238static void build_epilogue(struct jit_ctx *ctx)
239{
240 u16 reg_set = saved_regs(ctx);
241
242 if (ctx->seen & SEEN_MEM)
243 emit(ARM_ADD_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx);
244
245 reg_set &= ~(1 << ARM_LR);
246
247#ifdef CONFIG_FRAME_POINTER
248 /* the first instruction of the prologue was: mov ip, sp */
249 reg_set &= ~(1 << ARM_IP);
250 reg_set |= (1 << ARM_SP);
251 emit(ARM_LDM(ARM_SP, reg_set), ctx);
252#else
253 if (reg_set) {
254 if (ctx->seen & SEEN_CALL)
255 reg_set |= 1 << ARM_PC;
256 emit(ARM_POP(reg_set), ctx);
257 }
258
259 if (!(ctx->seen & SEEN_CALL))
260 emit(ARM_BX(ARM_LR), ctx);
261#endif
262}
263
264static int16_t imm8m(u32 x)
265{
266 u32 rot;
267
268 for (rot = 0; rot < 16; rot++)
269 if ((x & ~ror32(0xff, 2 * rot)) == 0)
270 return rol32(x, 2 * rot) | (rot << 8);
271
272 return -1;
273}
274
275#if __LINUX_ARM_ARCH__ < 7
276
277static u16 imm_offset(u32 k, struct jit_ctx *ctx)
278{
279 unsigned i = 0, offset;
280 u16 imm;
281
282 /* on the "fake" run we just count them (duplicates included) */
283 if (ctx->target == NULL) {
284 ctx->imm_count++;
285 return 0;
286 }
287
288 while ((i < ctx->imm_count) && ctx->imms[i]) {
289 if (ctx->imms[i] == k)
290 break;
291 i++;
292 }
293
294 if (ctx->imms[i] == 0)
295 ctx->imms[i] = k;
296
297 /* constants go just after the epilogue */
298 offset = ctx->offsets[ctx->skf->len];
299 offset += ctx->prologue_bytes;
300 offset += ctx->epilogue_bytes;
301 offset += i * 4;
302
303 ctx->target[offset / 4] = k;
304
305 /* PC in ARM mode == address of the instruction + 8 */
306 imm = offset - (8 + ctx->idx * 4);
307
308 if (imm & ~0xfff) {
309 /*
310 * literal pool is too far, signal it into flags. we
311 * can only detect it on the second pass unfortunately.
312 */
313 ctx->flags |= FLAG_IMM_OVERFLOW;
314 return 0;
315 }
316
317 return imm;
318}
319
320#endif /* __LINUX_ARM_ARCH__ */
321
322/*
323 * Move an immediate that's not an imm8m to a core register.
324 */
325static inline void emit_mov_i_no8m(int rd, u32 val, struct jit_ctx *ctx)
326{
327#if __LINUX_ARM_ARCH__ < 7
328 emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx);
329#else
330 emit(ARM_MOVW(rd, val & 0xffff), ctx);
331 if (val > 0xffff)
332 emit(ARM_MOVT(rd, val >> 16), ctx);
333#endif
334}
335
336static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx)
337{
338 int imm12 = imm8m(val);
339
340 if (imm12 >= 0)
341 emit(ARM_MOV_I(rd, imm12), ctx);
342 else
343 emit_mov_i_no8m(rd, val, ctx);
344}
345
346#if __LINUX_ARM_ARCH__ < 6
347
348static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
349{
350 _emit(cond, ARM_LDRB_I(ARM_R3, r_addr, 1), ctx);
351 _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx);
352 _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 3), ctx);
353 _emit(cond, ARM_LSL_I(ARM_R3, ARM_R3, 16), ctx);
354 _emit(cond, ARM_LDRB_I(ARM_R0, r_addr, 2), ctx);
355 _emit(cond, ARM_ORR_S(ARM_R3, ARM_R3, ARM_R1, SRTYPE_LSL, 24), ctx);
356 _emit(cond, ARM_ORR_R(ARM_R3, ARM_R3, ARM_R2), ctx);
357 _emit(cond, ARM_ORR_S(r_res, ARM_R3, ARM_R0, SRTYPE_LSL, 8), ctx);
358}
359
360static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
361{
362 _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx);
363 _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 1), ctx);
364 _emit(cond, ARM_ORR_S(r_res, ARM_R2, ARM_R1, SRTYPE_LSL, 8), ctx);
365}
366
367static inline void emit_swap16(u8 r_dst, u8 r_src, struct jit_ctx *ctx)
368{
369 /* r_dst = (r_src << 8) | (r_src >> 8) */
370 emit(ARM_LSL_I(ARM_R1, r_src, 8), ctx);
371 emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSR, 8), ctx);
372
373 /*
374 * we need to mask out the bits set in r_dst[23:16] due to
375 * the first shift instruction.
376 *
377 * note that 0x8ff is the encoded immediate 0x00ff0000.
378 */
379 emit(ARM_BIC_I(r_dst, r_dst, 0x8ff), ctx);
380}
381
382#else /* ARMv6+ */
383
384static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
385{
386 _emit(cond, ARM_LDR_I(r_res, r_addr, 0), ctx);
387#ifdef __LITTLE_ENDIAN
388 _emit(cond, ARM_REV(r_res, r_res), ctx);
389#endif
390}
391
392static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
393{
394 _emit(cond, ARM_LDRH_I(r_res, r_addr, 0), ctx);
395#ifdef __LITTLE_ENDIAN
396 _emit(cond, ARM_REV16(r_res, r_res), ctx);
397#endif
398}
399
400static inline void emit_swap16(u8 r_dst __maybe_unused,
401 u8 r_src __maybe_unused,
402 struct jit_ctx *ctx __maybe_unused)
403{
404#ifdef __LITTLE_ENDIAN
405 emit(ARM_REV16(r_dst, r_src), ctx);
406#endif
407}
408
409#endif /* __LINUX_ARM_ARCH__ < 6 */
410
411
412/* Compute the immediate value for a PC-relative branch. */
413static inline u32 b_imm(unsigned tgt, struct jit_ctx *ctx)
414{
415 u32 imm;
416
417 if (ctx->target == NULL)
418 return 0;
419 /*
420 * BPF allows only forward jumps and the offset of the target is
421 * still the one computed during the first pass.
422 */
423 imm = ctx->offsets[tgt] + ctx->prologue_bytes - (ctx->idx * 4 + 8);
424
425 return imm >> 2;
426}
427
428#define OP_IMM3(op, r1, r2, imm_val, ctx) \
429 do { \
430 imm12 = imm8m(imm_val); \
431 if (imm12 < 0) { \
432 emit_mov_i_no8m(r_scratch, imm_val, ctx); \
433 emit(op ## _R((r1), (r2), r_scratch), ctx); \
434 } else { \
435 emit(op ## _I((r1), (r2), imm12), ctx); \
436 } \
437 } while (0)
438
439static inline void emit_err_ret(u8 cond, struct jit_ctx *ctx)
440{
441 if (ctx->ret0_fp_idx >= 0) {
442 _emit(cond, ARM_B(b_imm(ctx->ret0_fp_idx, ctx)), ctx);
443 /* NOP to keep the size constant between passes */
444 emit(ARM_MOV_R(ARM_R0, ARM_R0), ctx);
445 } else {
446 _emit(cond, ARM_MOV_I(ARM_R0, 0), ctx);
447 _emit(cond, ARM_B(b_imm(ctx->skf->len, ctx)), ctx);
448 }
449}
450
451static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
452{
453#if __LINUX_ARM_ARCH__ < 5
454 emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx);
455
456 if (elf_hwcap & HWCAP_THUMB)
457 emit(ARM_BX(tgt_reg), ctx);
458 else
459 emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx);
460#else
461 emit(ARM_BLX_R(tgt_reg), ctx);
462#endif
463}
464
465static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx,
466 int bpf_op)
467{
468#if __LINUX_ARM_ARCH__ == 7
469 if (elf_hwcap & HWCAP_IDIVA) {
470 if (bpf_op == BPF_DIV)
471 emit(ARM_UDIV(rd, rm, rn), ctx);
472 else {
473 emit(ARM_UDIV(ARM_R3, rm, rn), ctx);
474 emit(ARM_MLS(rd, rn, ARM_R3, rm), ctx);
475 }
476 return;
477 }
478#endif
479
480 /*
481 * For BPF_ALU | BPF_DIV | BPF_K instructions, rm is ARM_R4
482 * (r_A) and rn is ARM_R0 (r_scratch) so load rn first into
483 * ARM_R1 to avoid accidentally overwriting ARM_R0 with rm
484 * before using it as a source for ARM_R1.
485 *
486 * For BPF_ALU | BPF_DIV | BPF_X rm is ARM_R4 (r_A) and rn is
487 * ARM_R5 (r_X) so there is no particular register overlap
488 * issues.
489 */
490 if (rn != ARM_R1)
491 emit(ARM_MOV_R(ARM_R1, rn), ctx);
492 if (rm != ARM_R0)
493 emit(ARM_MOV_R(ARM_R0, rm), ctx);
494
495 ctx->seen |= SEEN_CALL;
496 emit_mov_i(ARM_R3, bpf_op == BPF_DIV ? (u32)jit_udiv : (u32)jit_mod,
497 ctx);
498 emit_blx_r(ARM_R3, ctx);
499
500 if (rd != ARM_R0)
501 emit(ARM_MOV_R(rd, ARM_R0), ctx);
502}
503
504static inline void update_on_xread(struct jit_ctx *ctx)
505{
506 if (!(ctx->seen & SEEN_X))
507 ctx->flags |= FLAG_NEED_X_RESET;
508
509 ctx->seen |= SEEN_X;
510}
511
512static int build_body(struct jit_ctx *ctx)
513{
514 void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
515 const struct bpf_prog *prog = ctx->skf;
516 const struct sock_filter *inst;
517 unsigned i, load_order, off, condt;
518 int imm12;
519 u32 k;
520
521 for (i = 0; i < prog->len; i++) {
522 u16 code;
523
524 inst = &(prog->insns[i]);
525 /* K as an immediate value operand */
526 k = inst->k;
527 code = bpf_anc_helper(inst);
528
529 /* compute offsets only in the fake pass */
530 if (ctx->target == NULL)
531 ctx->offsets[i] = ctx->idx * 4;
532
533 switch (code) {
534 case BPF_LD | BPF_IMM:
535 emit_mov_i(r_A, k, ctx);
536 break;
537 case BPF_LD | BPF_W | BPF_LEN:
538 ctx->seen |= SEEN_SKB;
539 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
540 emit(ARM_LDR_I(r_A, r_skb,
541 offsetof(struct sk_buff, len)), ctx);
542 break;
543 case BPF_LD | BPF_MEM:
544 /* A = scratch[k] */
545 ctx->seen |= SEEN_MEM_WORD(k);
546 emit(ARM_LDR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx);
547 break;
548 case BPF_LD | BPF_W | BPF_ABS:
549 load_order = 2;
550 goto load;
551 case BPF_LD | BPF_H | BPF_ABS:
552 load_order = 1;
553 goto load;
554 case BPF_LD | BPF_B | BPF_ABS:
555 load_order = 0;
556load:
557 emit_mov_i(r_off, k, ctx);
558load_common:
559 ctx->seen |= SEEN_DATA | SEEN_CALL;
560
561 if (load_order > 0) {
562 emit(ARM_SUB_I(r_scratch, r_skb_hl,
563 1 << load_order), ctx);
564 emit(ARM_CMP_R(r_scratch, r_off), ctx);
565 condt = ARM_COND_GE;
566 } else {
567 emit(ARM_CMP_R(r_skb_hl, r_off), ctx);
568 condt = ARM_COND_HI;
569 }
570
571 /*
572 * test for negative offset, only if we are
573 * currently scheduled to take the fast
574 * path. this will update the flags so that
575 * the slowpath instruction are ignored if the
576 * offset is negative.
577 *
578 * for loard_order == 0 the HI condition will
579 * make loads at offset 0 take the slow path too.
580 */
581 _emit(condt, ARM_CMP_I(r_off, 0), ctx);
582
583 _emit(condt, ARM_ADD_R(r_scratch, r_off, r_skb_data),
584 ctx);
585
586 if (load_order == 0)
587 _emit(condt, ARM_LDRB_I(r_A, r_scratch, 0),
588 ctx);
589 else if (load_order == 1)
590 emit_load_be16(condt, r_A, r_scratch, ctx);
591 else if (load_order == 2)
592 emit_load_be32(condt, r_A, r_scratch, ctx);
593
594 _emit(condt, ARM_B(b_imm(i + 1, ctx)), ctx);
595
596 /* the slowpath */
597 emit_mov_i(ARM_R3, (u32)load_func[load_order], ctx);
598 emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
599 /* the offset is already in R1 */
600 emit_blx_r(ARM_R3, ctx);
601 /* check the result of skb_copy_bits */
602 emit(ARM_CMP_I(ARM_R1, 0), ctx);
603 emit_err_ret(ARM_COND_NE, ctx);
604 emit(ARM_MOV_R(r_A, ARM_R0), ctx);
605 break;
606 case BPF_LD | BPF_W | BPF_IND:
607 load_order = 2;
608 goto load_ind;
609 case BPF_LD | BPF_H | BPF_IND:
610 load_order = 1;
611 goto load_ind;
612 case BPF_LD | BPF_B | BPF_IND:
613 load_order = 0;
614load_ind:
615 update_on_xread(ctx);
616 OP_IMM3(ARM_ADD, r_off, r_X, k, ctx);
617 goto load_common;
618 case BPF_LDX | BPF_IMM:
619 ctx->seen |= SEEN_X;
620 emit_mov_i(r_X, k, ctx);
621 break;
622 case BPF_LDX | BPF_W | BPF_LEN:
623 ctx->seen |= SEEN_X | SEEN_SKB;
624 emit(ARM_LDR_I(r_X, r_skb,
625 offsetof(struct sk_buff, len)), ctx);
626 break;
627 case BPF_LDX | BPF_MEM:
628 ctx->seen |= SEEN_X | SEEN_MEM_WORD(k);
629 emit(ARM_LDR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx);
630 break;
631 case BPF_LDX | BPF_B | BPF_MSH:
632 /* x = ((*(frame + k)) & 0xf) << 2; */
633 ctx->seen |= SEEN_X | SEEN_DATA | SEEN_CALL;
634 /* the interpreter should deal with the negative K */
635 if ((int)k < 0)
636 return -1;
637 /* offset in r1: we might have to take the slow path */
638 emit_mov_i(r_off, k, ctx);
639 emit(ARM_CMP_R(r_skb_hl, r_off), ctx);
640
641 /* load in r0: common with the slowpath */
642 _emit(ARM_COND_HI, ARM_LDRB_R(ARM_R0, r_skb_data,
643 ARM_R1), ctx);
644 /*
645 * emit_mov_i() might generate one or two instructions,
646 * the same holds for emit_blx_r()
647 */
648 _emit(ARM_COND_HI, ARM_B(b_imm(i + 1, ctx) - 2), ctx);
649
650 emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
651 /* r_off is r1 */
652 emit_mov_i(ARM_R3, (u32)jit_get_skb_b, ctx);
653 emit_blx_r(ARM_R3, ctx);
654 /* check the return value of skb_copy_bits */
655 emit(ARM_CMP_I(ARM_R1, 0), ctx);
656 emit_err_ret(ARM_COND_NE, ctx);
657
658 emit(ARM_AND_I(r_X, ARM_R0, 0x00f), ctx);
659 emit(ARM_LSL_I(r_X, r_X, 2), ctx);
660 break;
661 case BPF_ST:
662 ctx->seen |= SEEN_MEM_WORD(k);
663 emit(ARM_STR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx);
664 break;
665 case BPF_STX:
666 update_on_xread(ctx);
667 ctx->seen |= SEEN_MEM_WORD(k);
668 emit(ARM_STR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx);
669 break;
670 case BPF_ALU | BPF_ADD | BPF_K:
671 /* A += K */
672 OP_IMM3(ARM_ADD, r_A, r_A, k, ctx);
673 break;
674 case BPF_ALU | BPF_ADD | BPF_X:
675 update_on_xread(ctx);
676 emit(ARM_ADD_R(r_A, r_A, r_X), ctx);
677 break;
678 case BPF_ALU | BPF_SUB | BPF_K:
679 /* A -= K */
680 OP_IMM3(ARM_SUB, r_A, r_A, k, ctx);
681 break;
682 case BPF_ALU | BPF_SUB | BPF_X:
683 update_on_xread(ctx);
684 emit(ARM_SUB_R(r_A, r_A, r_X), ctx);
685 break;
686 case BPF_ALU | BPF_MUL | BPF_K:
687 /* A *= K */
688 emit_mov_i(r_scratch, k, ctx);
689 emit(ARM_MUL(r_A, r_A, r_scratch), ctx);
690 break;
691 case BPF_ALU | BPF_MUL | BPF_X:
692 update_on_xread(ctx);
693 emit(ARM_MUL(r_A, r_A, r_X), ctx);
694 break;
695 case BPF_ALU | BPF_DIV | BPF_K:
696 if (k == 1)
697 break;
698 emit_mov_i(r_scratch, k, ctx);
699 emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_DIV);
700 break;
701 case BPF_ALU | BPF_DIV | BPF_X:
702 update_on_xread(ctx);
703 emit(ARM_CMP_I(r_X, 0), ctx);
704 emit_err_ret(ARM_COND_EQ, ctx);
705 emit_udivmod(r_A, r_A, r_X, ctx, BPF_DIV);
706 break;
707 case BPF_ALU | BPF_MOD | BPF_K:
708 if (k == 1) {
709 emit_mov_i(r_A, 0, ctx);
710 break;
711 }
712 emit_mov_i(r_scratch, k, ctx);
713 emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_MOD);
714 break;
715 case BPF_ALU | BPF_MOD | BPF_X:
716 update_on_xread(ctx);
717 emit(ARM_CMP_I(r_X, 0), ctx);
718 emit_err_ret(ARM_COND_EQ, ctx);
719 emit_udivmod(r_A, r_A, r_X, ctx, BPF_MOD);
720 break;
721 case BPF_ALU | BPF_OR | BPF_K:
722 /* A |= K */
723 OP_IMM3(ARM_ORR, r_A, r_A, k, ctx);
724 break;
725 case BPF_ALU | BPF_OR | BPF_X:
726 update_on_xread(ctx);
727 emit(ARM_ORR_R(r_A, r_A, r_X), ctx);
728 break;
729 case BPF_ALU | BPF_XOR | BPF_K:
730 /* A ^= K; */
731 OP_IMM3(ARM_EOR, r_A, r_A, k, ctx);
732 break;
733 case BPF_ANC | SKF_AD_ALU_XOR_X:
734 case BPF_ALU | BPF_XOR | BPF_X:
735 /* A ^= X */
736 update_on_xread(ctx);
737 emit(ARM_EOR_R(r_A, r_A, r_X), ctx);
738 break;
739 case BPF_ALU | BPF_AND | BPF_K:
740 /* A &= K */
741 OP_IMM3(ARM_AND, r_A, r_A, k, ctx);
742 break;
743 case BPF_ALU | BPF_AND | BPF_X:
744 update_on_xread(ctx);
745 emit(ARM_AND_R(r_A, r_A, r_X), ctx);
746 break;
747 case BPF_ALU | BPF_LSH | BPF_K:
748 if (unlikely(k > 31))
749 return -1;
750 emit(ARM_LSL_I(r_A, r_A, k), ctx);
751 break;
752 case BPF_ALU | BPF_LSH | BPF_X:
753 update_on_xread(ctx);
754 emit(ARM_LSL_R(r_A, r_A, r_X), ctx);
755 break;
756 case BPF_ALU | BPF_RSH | BPF_K:
757 if (unlikely(k > 31))
758 return -1;
759 if (k)
760 emit(ARM_LSR_I(r_A, r_A, k), ctx);
761 break;
762 case BPF_ALU | BPF_RSH | BPF_X:
763 update_on_xread(ctx);
764 emit(ARM_LSR_R(r_A, r_A, r_X), ctx);
765 break;
766 case BPF_ALU | BPF_NEG:
767 /* A = -A */
768 emit(ARM_RSB_I(r_A, r_A, 0), ctx);
769 break;
770 case BPF_JMP | BPF_JA:
771 /* pc += K */
772 emit(ARM_B(b_imm(i + k + 1, ctx)), ctx);
773 break;
774 case BPF_JMP | BPF_JEQ | BPF_K:
775 /* pc += (A == K) ? pc->jt : pc->jf */
776 condt = ARM_COND_EQ;
777 goto cmp_imm;
778 case BPF_JMP | BPF_JGT | BPF_K:
779 /* pc += (A > K) ? pc->jt : pc->jf */
780 condt = ARM_COND_HI;
781 goto cmp_imm;
782 case BPF_JMP | BPF_JGE | BPF_K:
783 /* pc += (A >= K) ? pc->jt : pc->jf */
784 condt = ARM_COND_HS;
785cmp_imm:
786 imm12 = imm8m(k);
787 if (imm12 < 0) {
788 emit_mov_i_no8m(r_scratch, k, ctx);
789 emit(ARM_CMP_R(r_A, r_scratch), ctx);
790 } else {
791 emit(ARM_CMP_I(r_A, imm12), ctx);
792 }
793cond_jump:
794 if (inst->jt)
795 _emit(condt, ARM_B(b_imm(i + inst->jt + 1,
796 ctx)), ctx);
797 if (inst->jf)
798 _emit(condt ^ 1, ARM_B(b_imm(i + inst->jf + 1,
799 ctx)), ctx);
800 break;
801 case BPF_JMP | BPF_JEQ | BPF_X:
802 /* pc += (A == X) ? pc->jt : pc->jf */
803 condt = ARM_COND_EQ;
804 goto cmp_x;
805 case BPF_JMP | BPF_JGT | BPF_X:
806 /* pc += (A > X) ? pc->jt : pc->jf */
807 condt = ARM_COND_HI;
808 goto cmp_x;
809 case BPF_JMP | BPF_JGE | BPF_X:
810 /* pc += (A >= X) ? pc->jt : pc->jf */
811 condt = ARM_COND_CS;
812cmp_x:
813 update_on_xread(ctx);
814 emit(ARM_CMP_R(r_A, r_X), ctx);
815 goto cond_jump;
816 case BPF_JMP | BPF_JSET | BPF_K:
817 /* pc += (A & K) ? pc->jt : pc->jf */
818 condt = ARM_COND_NE;
819 /* not set iff all zeroes iff Z==1 iff EQ */
820
821 imm12 = imm8m(k);
822 if (imm12 < 0) {
823 emit_mov_i_no8m(r_scratch, k, ctx);
824 emit(ARM_TST_R(r_A, r_scratch), ctx);
825 } else {
826 emit(ARM_TST_I(r_A, imm12), ctx);
827 }
828 goto cond_jump;
829 case BPF_JMP | BPF_JSET | BPF_X:
830 /* pc += (A & X) ? pc->jt : pc->jf */
831 update_on_xread(ctx);
832 condt = ARM_COND_NE;
833 emit(ARM_TST_R(r_A, r_X), ctx);
834 goto cond_jump;
835 case BPF_RET | BPF_A:
836 emit(ARM_MOV_R(ARM_R0, r_A), ctx);
837 goto b_epilogue;
838 case BPF_RET | BPF_K:
839 if ((k == 0) && (ctx->ret0_fp_idx < 0))
840 ctx->ret0_fp_idx = i;
841 emit_mov_i(ARM_R0, k, ctx);
842b_epilogue:
843 if (i != ctx->skf->len - 1)
844 emit(ARM_B(b_imm(prog->len, ctx)), ctx);
845 break;
846 case BPF_MISC | BPF_TAX:
847 /* X = A */
848 ctx->seen |= SEEN_X;
849 emit(ARM_MOV_R(r_X, r_A), ctx);
850 break;
851 case BPF_MISC | BPF_TXA:
852 /* A = X */
853 update_on_xread(ctx);
854 emit(ARM_MOV_R(r_A, r_X), ctx);
855 break;
856 case BPF_ANC | SKF_AD_PROTOCOL:
857 /* A = ntohs(skb->protocol) */
858 ctx->seen |= SEEN_SKB;
859 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
860 protocol) != 2);
861 off = offsetof(struct sk_buff, protocol);
862 emit(ARM_LDRH_I(r_scratch, r_skb, off), ctx);
863 emit_swap16(r_A, r_scratch, ctx);
864 break;
865 case BPF_ANC | SKF_AD_CPU:
866 /* r_scratch = current_thread_info() */
867 OP_IMM3(ARM_BIC, r_scratch, ARM_SP, THREAD_SIZE - 1, ctx);
868 /* A = current_thread_info()->cpu */
869 BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4);
870 off = offsetof(struct thread_info, cpu);
871 emit(ARM_LDR_I(r_A, r_scratch, off), ctx);
872 break;
873 case BPF_ANC | SKF_AD_IFINDEX:
874 case BPF_ANC | SKF_AD_HATYPE:
875 /* A = skb->dev->ifindex */
876 /* A = skb->dev->type */
877 ctx->seen |= SEEN_SKB;
878 off = offsetof(struct sk_buff, dev);
879 emit(ARM_LDR_I(r_scratch, r_skb, off), ctx);
880
881 emit(ARM_CMP_I(r_scratch, 0), ctx);
882 emit_err_ret(ARM_COND_EQ, ctx);
883
884 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
885 ifindex) != 4);
886 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
887 type) != 2);
888
889 if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
890 off = offsetof(struct net_device, ifindex);
891 emit(ARM_LDR_I(r_A, r_scratch, off), ctx);
892 } else {
893 /*
894 * offset of field "type" in "struct
895 * net_device" is above what can be
896 * used in the ldrh rd, [rn, #imm]
897 * instruction, so load the offset in
898 * a register and use ldrh rd, [rn, rm]
899 */
900 off = offsetof(struct net_device, type);
901 emit_mov_i(ARM_R3, off, ctx);
902 emit(ARM_LDRH_R(r_A, r_scratch, ARM_R3), ctx);
903 }
904 break;
905 case BPF_ANC | SKF_AD_MARK:
906 ctx->seen |= SEEN_SKB;
907 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
908 off = offsetof(struct sk_buff, mark);
909 emit(ARM_LDR_I(r_A, r_skb, off), ctx);
910 break;
911 case BPF_ANC | SKF_AD_RXHASH:
912 ctx->seen |= SEEN_SKB;
913 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
914 off = offsetof(struct sk_buff, hash);
915 emit(ARM_LDR_I(r_A, r_skb, off), ctx);
916 break;
917 case BPF_ANC | SKF_AD_VLAN_TAG:
918 case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
919 ctx->seen |= SEEN_SKB;
920 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
921 off = offsetof(struct sk_buff, vlan_tci);
922 emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
923 if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
924 OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx);
925 else {
926 OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx);
927 OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx);
928 }
929 break;
930 case BPF_ANC | SKF_AD_PKTTYPE:
931 ctx->seen |= SEEN_SKB;
932 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
933 __pkt_type_offset[0]) != 1);
934 off = PKT_TYPE_OFFSET();
935 emit(ARM_LDRB_I(r_A, r_skb, off), ctx);
936 emit(ARM_AND_I(r_A, r_A, PKT_TYPE_MAX), ctx);
937#ifdef __BIG_ENDIAN_BITFIELD
938 emit(ARM_LSR_I(r_A, r_A, 5), ctx);
939#endif
940 break;
941 case BPF_ANC | SKF_AD_QUEUE:
942 ctx->seen |= SEEN_SKB;
943 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
944 queue_mapping) != 2);
945 BUILD_BUG_ON(offsetof(struct sk_buff,
946 queue_mapping) > 0xff);
947 off = offsetof(struct sk_buff, queue_mapping);
948 emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
949 break;
950 case BPF_ANC | SKF_AD_PAY_OFFSET:
951 ctx->seen |= SEEN_SKB | SEEN_CALL;
952
953 emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
954 emit_mov_i(ARM_R3, (unsigned int)skb_get_poff, ctx);
955 emit_blx_r(ARM_R3, ctx);
956 emit(ARM_MOV_R(r_A, ARM_R0), ctx);
957 break;
958 case BPF_LDX | BPF_W | BPF_ABS:
959 /*
960 * load a 32bit word from struct seccomp_data.
961 * seccomp_check_filter() will already have checked
962 * that k is 32bit aligned and lies within the
963 * struct seccomp_data.
964 */
965 ctx->seen |= SEEN_SKB;
966 emit(ARM_LDR_I(r_A, r_skb, k), ctx);
967 break;
968 default:
969 return -1;
970 }
971
972 if (ctx->flags & FLAG_IMM_OVERFLOW)
973 /*
974 * this instruction generated an overflow when
975 * trying to access the literal pool, so
976 * delegate this filter to the kernel interpreter.
977 */
978 return -1;
979 }
980
981 /* compute offsets only during the first pass */
982 if (ctx->target == NULL)
983 ctx->offsets[i] = ctx->idx * 4;
984
985 return 0;
986}
987
988
989void bpf_jit_compile(struct bpf_prog *fp)
990{
991 struct bpf_binary_header *header;
992 struct jit_ctx ctx;
993 unsigned tmp_idx;
994 unsigned alloc_size;
995 u8 *target_ptr;
996
997 if (!bpf_jit_enable)
998 return;
999
1000 memset(&ctx, 0, sizeof(ctx));
1001 ctx.skf = fp;
1002 ctx.ret0_fp_idx = -1;
1003
1004 ctx.offsets = kzalloc(4 * (ctx.skf->len + 1), GFP_KERNEL);
1005 if (ctx.offsets == NULL)
1006 return;
1007
1008 /* fake pass to fill in the ctx->seen */
1009 if (unlikely(build_body(&ctx)))
1010 goto out;
1011
1012 tmp_idx = ctx.idx;
1013 build_prologue(&ctx);
1014 ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
1015
1016#if __LINUX_ARM_ARCH__ < 7
1017 tmp_idx = ctx.idx;
1018 build_epilogue(&ctx);
1019 ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4;
1020
1021 ctx.idx += ctx.imm_count;
1022 if (ctx.imm_count) {
1023 ctx.imms = kzalloc(4 * ctx.imm_count, GFP_KERNEL);
1024 if (ctx.imms == NULL)
1025 goto out;
1026 }
1027#else
1028 /* there's nothing after the epilogue on ARMv7 */
1029 build_epilogue(&ctx);
1030#endif
1031 alloc_size = 4 * ctx.idx;
1032 header = bpf_jit_binary_alloc(alloc_size, &target_ptr,
1033 4, jit_fill_hole);
1034 if (header == NULL)
1035 goto out;
1036
1037 ctx.target = (u32 *) target_ptr;
1038 ctx.idx = 0;
1039
1040 build_prologue(&ctx);
1041 if (build_body(&ctx) < 0) {
1042#if __LINUX_ARM_ARCH__ < 7
1043 if (ctx.imm_count)
1044 kfree(ctx.imms);
1045#endif
1046 bpf_jit_binary_free(header);
1047 goto out;
1048 }
1049 build_epilogue(&ctx);
1050
1051 flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
1052
1053#if __LINUX_ARM_ARCH__ < 7
1054 if (ctx.imm_count)
1055 kfree(ctx.imms);
1056#endif
1057
1058 if (bpf_jit_enable > 1)
1059 /* there are 2 passes here */
1060 bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
1061
1062 set_memory_ro((unsigned long)header, header->pages);
1063 fp->bpf_func = (void *)ctx.target;
1064 fp->jited = 1;
1065out:
1066 kfree(ctx.offsets);
1067 return;
1068}
1069
1070void bpf_jit_free(struct bpf_prog *fp)
1071{
1072 unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
1073 struct bpf_binary_header *header = (void *)addr;
1074
1075 if (!fp->jited)
1076 goto free_filter;
1077
1078 set_memory_rw(addr, header->pages);
1079 bpf_jit_binary_free(header);
1080
1081free_filter:
1082 bpf_prog_unlock_free(fp);
1083}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Just-In-Time compiler for eBPF filters on 32bit ARM
4 *
5 * Copyright (c) 2017 Shubham Bansal <illusionist.neo@gmail.com>
6 * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com>
7 */
8
9#include <linux/bpf.h>
10#include <linux/bitops.h>
11#include <linux/compiler.h>
12#include <linux/errno.h>
13#include <linux/filter.h>
14#include <linux/netdevice.h>
15#include <linux/string.h>
16#include <linux/slab.h>
17#include <linux/if_vlan.h>
18
19#include <asm/cacheflush.h>
20#include <asm/hwcap.h>
21#include <asm/opcodes.h>
22#include <asm/system_info.h>
23
24#include "bpf_jit_32.h"
25
26/*
27 * eBPF prog stack layout:
28 *
29 * high
30 * original ARM_SP => +-----+
31 * | | callee saved registers
32 * +-----+ <= (BPF_FP + SCRATCH_SIZE)
33 * | ... | eBPF JIT scratch space
34 * eBPF fp register => +-----+
35 * (BPF_FP) | ... | eBPF prog stack
36 * +-----+
37 * |RSVD | JIT scratchpad
38 * current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE + SCRATCH_SIZE)
39 * | |
40 * | ... | Function call stack
41 * | |
42 * +-----+
43 * low
44 *
45 * The callee saved registers depends on whether frame pointers are enabled.
46 * With frame pointers (to be compliant with the ABI):
47 *
48 * high
49 * original ARM_SP => +--------------+ \
50 * | pc | |
51 * current ARM_FP => +--------------+ } callee saved registers
52 * |r4-r9,fp,ip,lr| |
53 * +--------------+ /
54 * low
55 *
56 * Without frame pointers:
57 *
58 * high
59 * original ARM_SP => +--------------+
60 * | r4-r9,fp,lr | callee saved registers
61 * current ARM_FP => +--------------+
62 * low
63 *
64 * When popping registers off the stack at the end of a BPF function, we
65 * reference them via the current ARM_FP register.
66 */
67#define CALLEE_MASK (1 << ARM_R4 | 1 << ARM_R5 | 1 << ARM_R6 | \
68 1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R9 | \
69 1 << ARM_FP)
70#define CALLEE_PUSH_MASK (CALLEE_MASK | 1 << ARM_LR)
71#define CALLEE_POP_MASK (CALLEE_MASK | 1 << ARM_PC)
72
73enum {
74 /* Stack layout - these are offsets from (top of stack - 4) */
75 BPF_R2_HI,
76 BPF_R2_LO,
77 BPF_R3_HI,
78 BPF_R3_LO,
79 BPF_R4_HI,
80 BPF_R4_LO,
81 BPF_R5_HI,
82 BPF_R5_LO,
83 BPF_R7_HI,
84 BPF_R7_LO,
85 BPF_R8_HI,
86 BPF_R8_LO,
87 BPF_R9_HI,
88 BPF_R9_LO,
89 BPF_FP_HI,
90 BPF_FP_LO,
91 BPF_TC_HI,
92 BPF_TC_LO,
93 BPF_AX_HI,
94 BPF_AX_LO,
95 /* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4,
96 * BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9,
97 * BPF_REG_FP and Tail call counts.
98 */
99 BPF_JIT_SCRATCH_REGS,
100};
101
102/*
103 * Negative "register" values indicate the register is stored on the stack
104 * and are the offset from the top of the eBPF JIT scratch space.
105 */
106#define STACK_OFFSET(k) (-4 - (k) * 4)
107#define SCRATCH_SIZE (BPF_JIT_SCRATCH_REGS * 4)
108
109#ifdef CONFIG_FRAME_POINTER
110#define EBPF_SCRATCH_TO_ARM_FP(x) ((x) - 4 * hweight16(CALLEE_PUSH_MASK) - 4)
111#else
112#define EBPF_SCRATCH_TO_ARM_FP(x) (x)
113#endif
114
115#define TMP_REG_1 (MAX_BPF_JIT_REG + 0) /* TEMP Register 1 */
116#define TMP_REG_2 (MAX_BPF_JIT_REG + 1) /* TEMP Register 2 */
117#define TCALL_CNT (MAX_BPF_JIT_REG + 2) /* Tail Call Count */
118
119#define FLAG_IMM_OVERFLOW (1 << 0)
120
121/*
122 * Map eBPF registers to ARM 32bit registers or stack scratch space.
123 *
124 * 1. First argument is passed using the arm 32bit registers and rest of the
125 * arguments are passed on stack scratch space.
126 * 2. First callee-saved argument is mapped to arm 32 bit registers and rest
127 * arguments are mapped to scratch space on stack.
128 * 3. We need two 64 bit temp registers to do complex operations on eBPF
129 * registers.
130 *
131 * As the eBPF registers are all 64 bit registers and arm has only 32 bit
132 * registers, we have to map each eBPF registers with two arm 32 bit regs or
133 * scratch memory space and we have to build eBPF 64 bit register from those.
134 *
135 */
136static const s8 bpf2a32[][2] = {
137 /* return value from in-kernel function, and exit value from eBPF */
138 [BPF_REG_0] = {ARM_R1, ARM_R0},
139 /* arguments from eBPF program to in-kernel function */
140 [BPF_REG_1] = {ARM_R3, ARM_R2},
141 /* Stored on stack scratch space */
142 [BPF_REG_2] = {STACK_OFFSET(BPF_R2_HI), STACK_OFFSET(BPF_R2_LO)},
143 [BPF_REG_3] = {STACK_OFFSET(BPF_R3_HI), STACK_OFFSET(BPF_R3_LO)},
144 [BPF_REG_4] = {STACK_OFFSET(BPF_R4_HI), STACK_OFFSET(BPF_R4_LO)},
145 [BPF_REG_5] = {STACK_OFFSET(BPF_R5_HI), STACK_OFFSET(BPF_R5_LO)},
146 /* callee saved registers that in-kernel function will preserve */
147 [BPF_REG_6] = {ARM_R5, ARM_R4},
148 /* Stored on stack scratch space */
149 [BPF_REG_7] = {STACK_OFFSET(BPF_R7_HI), STACK_OFFSET(BPF_R7_LO)},
150 [BPF_REG_8] = {STACK_OFFSET(BPF_R8_HI), STACK_OFFSET(BPF_R8_LO)},
151 [BPF_REG_9] = {STACK_OFFSET(BPF_R9_HI), STACK_OFFSET(BPF_R9_LO)},
152 /* Read only Frame Pointer to access Stack */
153 [BPF_REG_FP] = {STACK_OFFSET(BPF_FP_HI), STACK_OFFSET(BPF_FP_LO)},
154 /* Temporary Register for internal BPF JIT, can be used
155 * for constant blindings and others.
156 */
157 [TMP_REG_1] = {ARM_R7, ARM_R6},
158 [TMP_REG_2] = {ARM_R9, ARM_R8},
159 /* Tail call count. Stored on stack scratch space. */
160 [TCALL_CNT] = {STACK_OFFSET(BPF_TC_HI), STACK_OFFSET(BPF_TC_LO)},
161 /* temporary register for blinding constants.
162 * Stored on stack scratch space.
163 */
164 [BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)},
165};
166
167#define dst_lo dst[1]
168#define dst_hi dst[0]
169#define src_lo src[1]
170#define src_hi src[0]
171
172/*
173 * JIT Context:
174 *
175 * prog : bpf_prog
176 * idx : index of current last JITed instruction.
177 * prologue_bytes : bytes used in prologue.
178 * epilogue_offset : offset of epilogue starting.
179 * offsets : array of eBPF instruction offsets in
180 * JITed code.
181 * target : final JITed code.
182 * epilogue_bytes : no of bytes used in epilogue.
183 * imm_count : no of immediate counts used for global
184 * variables.
185 * imms : array of global variable addresses.
186 */
187
188struct jit_ctx {
189 const struct bpf_prog *prog;
190 unsigned int idx;
191 unsigned int prologue_bytes;
192 unsigned int epilogue_offset;
193 unsigned int cpu_architecture;
194 u32 flags;
195 u32 *offsets;
196 u32 *target;
197 u32 stack_size;
198#if __LINUX_ARM_ARCH__ < 7
199 u16 epilogue_bytes;
200 u16 imm_count;
201 u32 *imms;
202#endif
203};
204
205/*
206 * Wrappers which handle both OABI and EABI and assures Thumb2 interworking
207 * (where the assembly routines like __aeabi_uidiv could cause problems).
208 */
209static u32 jit_udiv32(u32 dividend, u32 divisor)
210{
211 return dividend / divisor;
212}
213
214static u32 jit_mod32(u32 dividend, u32 divisor)
215{
216 return dividend % divisor;
217}
218
219static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx)
220{
221 inst |= (cond << 28);
222 inst = __opcode_to_mem_arm(inst);
223
224 if (ctx->target != NULL)
225 ctx->target[ctx->idx] = inst;
226
227 ctx->idx++;
228}
229
230/*
231 * Emit an instruction that will be executed unconditionally.
232 */
233static inline void emit(u32 inst, struct jit_ctx *ctx)
234{
235 _emit(ARM_COND_AL, inst, ctx);
236}
237
238/*
239 * This is rather horrid, but necessary to convert an integer constant
240 * to an immediate operand for the opcodes, and be able to detect at
241 * build time whether the constant can't be converted (iow, usable in
242 * BUILD_BUG_ON()).
243 */
244#define imm12val(v, s) (rol32(v, (s)) | (s) << 7)
245#define const_imm8m(x) \
246 ({ int r; \
247 u32 v = (x); \
248 if (!(v & ~0x000000ff)) \
249 r = imm12val(v, 0); \
250 else if (!(v & ~0xc000003f)) \
251 r = imm12val(v, 2); \
252 else if (!(v & ~0xf000000f)) \
253 r = imm12val(v, 4); \
254 else if (!(v & ~0xfc000003)) \
255 r = imm12val(v, 6); \
256 else if (!(v & ~0xff000000)) \
257 r = imm12val(v, 8); \
258 else if (!(v & ~0x3fc00000)) \
259 r = imm12val(v, 10); \
260 else if (!(v & ~0x0ff00000)) \
261 r = imm12val(v, 12); \
262 else if (!(v & ~0x03fc0000)) \
263 r = imm12val(v, 14); \
264 else if (!(v & ~0x00ff0000)) \
265 r = imm12val(v, 16); \
266 else if (!(v & ~0x003fc000)) \
267 r = imm12val(v, 18); \
268 else if (!(v & ~0x000ff000)) \
269 r = imm12val(v, 20); \
270 else if (!(v & ~0x0003fc00)) \
271 r = imm12val(v, 22); \
272 else if (!(v & ~0x0000ff00)) \
273 r = imm12val(v, 24); \
274 else if (!(v & ~0x00003fc0)) \
275 r = imm12val(v, 26); \
276 else if (!(v & ~0x00000ff0)) \
277 r = imm12val(v, 28); \
278 else if (!(v & ~0x000003fc)) \
279 r = imm12val(v, 30); \
280 else \
281 r = -1; \
282 r; })
283
284/*
285 * Checks if immediate value can be converted to imm12(12 bits) value.
286 */
287static int imm8m(u32 x)
288{
289 u32 rot;
290
291 for (rot = 0; rot < 16; rot++)
292 if ((x & ~ror32(0xff, 2 * rot)) == 0)
293 return rol32(x, 2 * rot) | (rot << 8);
294 return -1;
295}
296
297#define imm8m(x) (__builtin_constant_p(x) ? const_imm8m(x) : imm8m(x))
298
299static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12)
300{
301 op |= rt << 12 | rn << 16;
302 if (imm12 >= 0)
303 op |= ARM_INST_LDST__U;
304 else
305 imm12 = -imm12;
306 return op | (imm12 & ARM_INST_LDST__IMM12);
307}
308
309static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8)
310{
311 op |= rt << 12 | rn << 16;
312 if (imm8 >= 0)
313 op |= ARM_INST_LDST__U;
314 else
315 imm8 = -imm8;
316 return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f);
317}
318
319#define ARM_LDR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off)
320#define ARM_LDRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off)
321#define ARM_LDRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRD_I, rt, rn, off)
322#define ARM_LDRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off)
323
324#define ARM_STR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off)
325#define ARM_STRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off)
326#define ARM_STRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRD_I, rt, rn, off)
327#define ARM_STRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off)
328
329/*
330 * Initializes the JIT space with undefined instructions.
331 */
332static void jit_fill_hole(void *area, unsigned int size)
333{
334 u32 *ptr;
335 /* We are guaranteed to have aligned memory. */
336 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
337 *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF);
338}
339
340#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
341/* EABI requires the stack to be aligned to 64-bit boundaries */
342#define STACK_ALIGNMENT 8
343#else
344/* Stack must be aligned to 32-bit boundaries */
345#define STACK_ALIGNMENT 4
346#endif
347
348/* total stack size used in JITed code */
349#define _STACK_SIZE (ctx->prog->aux->stack_depth + SCRATCH_SIZE)
350#define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT)
351
352#if __LINUX_ARM_ARCH__ < 7
353
354static u16 imm_offset(u32 k, struct jit_ctx *ctx)
355{
356 unsigned int i = 0, offset;
357 u16 imm;
358
359 /* on the "fake" run we just count them (duplicates included) */
360 if (ctx->target == NULL) {
361 ctx->imm_count++;
362 return 0;
363 }
364
365 while ((i < ctx->imm_count) && ctx->imms[i]) {
366 if (ctx->imms[i] == k)
367 break;
368 i++;
369 }
370
371 if (ctx->imms[i] == 0)
372 ctx->imms[i] = k;
373
374 /* constants go just after the epilogue */
375 offset = ctx->offsets[ctx->prog->len - 1] * 4;
376 offset += ctx->prologue_bytes;
377 offset += ctx->epilogue_bytes;
378 offset += i * 4;
379
380 ctx->target[offset / 4] = k;
381
382 /* PC in ARM mode == address of the instruction + 8 */
383 imm = offset - (8 + ctx->idx * 4);
384
385 if (imm & ~0xfff) {
386 /*
387 * literal pool is too far, signal it into flags. we
388 * can only detect it on the second pass unfortunately.
389 */
390 ctx->flags |= FLAG_IMM_OVERFLOW;
391 return 0;
392 }
393
394 return imm;
395}
396
397#endif /* __LINUX_ARM_ARCH__ */
398
399static inline int bpf2a32_offset(int bpf_to, int bpf_from,
400 const struct jit_ctx *ctx) {
401 int to, from;
402
403 if (ctx->target == NULL)
404 return 0;
405 to = ctx->offsets[bpf_to];
406 from = ctx->offsets[bpf_from];
407
408 return to - from - 1;
409}
410
411/*
412 * Move an immediate that's not an imm8m to a core register.
413 */
414static inline void emit_mov_i_no8m(const u8 rd, u32 val, struct jit_ctx *ctx)
415{
416#if __LINUX_ARM_ARCH__ < 7
417 emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx);
418#else
419 emit(ARM_MOVW(rd, val & 0xffff), ctx);
420 if (val > 0xffff)
421 emit(ARM_MOVT(rd, val >> 16), ctx);
422#endif
423}
424
425static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx)
426{
427 int imm12 = imm8m(val);
428
429 if (imm12 >= 0)
430 emit(ARM_MOV_I(rd, imm12), ctx);
431 else
432 emit_mov_i_no8m(rd, val, ctx);
433}
434
435static void emit_bx_r(u8 tgt_reg, struct jit_ctx *ctx)
436{
437 if (elf_hwcap & HWCAP_THUMB)
438 emit(ARM_BX(tgt_reg), ctx);
439 else
440 emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx);
441}
442
443static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
444{
445#if __LINUX_ARM_ARCH__ < 5
446 emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx);
447 emit_bx_r(tgt_reg, ctx);
448#else
449 emit(ARM_BLX_R(tgt_reg), ctx);
450#endif
451}
452
453static inline int epilogue_offset(const struct jit_ctx *ctx)
454{
455 int to, from;
456 /* No need for 1st dummy run */
457 if (ctx->target == NULL)
458 return 0;
459 to = ctx->epilogue_offset;
460 from = ctx->idx;
461
462 return to - from - 2;
463}
464
465static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op)
466{
467 const s8 *tmp = bpf2a32[TMP_REG_1];
468
469#if __LINUX_ARM_ARCH__ == 7
470 if (elf_hwcap & HWCAP_IDIVA) {
471 if (op == BPF_DIV)
472 emit(ARM_UDIV(rd, rm, rn), ctx);
473 else {
474 emit(ARM_UDIV(ARM_IP, rm, rn), ctx);
475 emit(ARM_MLS(rd, rn, ARM_IP, rm), ctx);
476 }
477 return;
478 }
479#endif
480
481 /*
482 * For BPF_ALU | BPF_DIV | BPF_K instructions
483 * As ARM_R1 and ARM_R0 contains 1st argument of bpf
484 * function, we need to save it on caller side to save
485 * it from getting destroyed within callee.
486 * After the return from the callee, we restore ARM_R0
487 * ARM_R1.
488 */
489 if (rn != ARM_R1) {
490 emit(ARM_MOV_R(tmp[0], ARM_R1), ctx);
491 emit(ARM_MOV_R(ARM_R1, rn), ctx);
492 }
493 if (rm != ARM_R0) {
494 emit(ARM_MOV_R(tmp[1], ARM_R0), ctx);
495 emit(ARM_MOV_R(ARM_R0, rm), ctx);
496 }
497
498 /* Call appropriate function */
499 emit_mov_i(ARM_IP, op == BPF_DIV ?
500 (u32)jit_udiv32 : (u32)jit_mod32, ctx);
501 emit_blx_r(ARM_IP, ctx);
502
503 /* Save return value */
504 if (rd != ARM_R0)
505 emit(ARM_MOV_R(rd, ARM_R0), ctx);
506
507 /* Restore ARM_R0 and ARM_R1 */
508 if (rn != ARM_R1)
509 emit(ARM_MOV_R(ARM_R1, tmp[0]), ctx);
510 if (rm != ARM_R0)
511 emit(ARM_MOV_R(ARM_R0, tmp[1]), ctx);
512}
513
514/* Is the translated BPF register on stack? */
515static bool is_stacked(s8 reg)
516{
517 return reg < 0;
518}
519
520/* If a BPF register is on the stack (stk is true), load it to the
521 * supplied temporary register and return the temporary register
522 * for subsequent operations, otherwise just use the CPU register.
523 */
524static s8 arm_bpf_get_reg32(s8 reg, s8 tmp, struct jit_ctx *ctx)
525{
526 if (is_stacked(reg)) {
527 emit(ARM_LDR_I(tmp, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx);
528 reg = tmp;
529 }
530 return reg;
531}
532
533static const s8 *arm_bpf_get_reg64(const s8 *reg, const s8 *tmp,
534 struct jit_ctx *ctx)
535{
536 if (is_stacked(reg[1])) {
537 if (__LINUX_ARM_ARCH__ >= 6 ||
538 ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {
539 emit(ARM_LDRD_I(tmp[1], ARM_FP,
540 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
541 } else {
542 emit(ARM_LDR_I(tmp[1], ARM_FP,
543 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
544 emit(ARM_LDR_I(tmp[0], ARM_FP,
545 EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);
546 }
547 reg = tmp;
548 }
549 return reg;
550}
551
552/* If a BPF register is on the stack (stk is true), save the register
553 * back to the stack. If the source register is not the same, then
554 * move it into the correct register.
555 */
556static void arm_bpf_put_reg32(s8 reg, s8 src, struct jit_ctx *ctx)
557{
558 if (is_stacked(reg))
559 emit(ARM_STR_I(src, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx);
560 else if (reg != src)
561 emit(ARM_MOV_R(reg, src), ctx);
562}
563
564static void arm_bpf_put_reg64(const s8 *reg, const s8 *src,
565 struct jit_ctx *ctx)
566{
567 if (is_stacked(reg[1])) {
568 if (__LINUX_ARM_ARCH__ >= 6 ||
569 ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {
570 emit(ARM_STRD_I(src[1], ARM_FP,
571 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
572 } else {
573 emit(ARM_STR_I(src[1], ARM_FP,
574 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
575 emit(ARM_STR_I(src[0], ARM_FP,
576 EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);
577 }
578 } else {
579 if (reg[1] != src[1])
580 emit(ARM_MOV_R(reg[1], src[1]), ctx);
581 if (reg[0] != src[0])
582 emit(ARM_MOV_R(reg[0], src[0]), ctx);
583 }
584}
585
586static inline void emit_a32_mov_i(const s8 dst, const u32 val,
587 struct jit_ctx *ctx)
588{
589 const s8 *tmp = bpf2a32[TMP_REG_1];
590
591 if (is_stacked(dst)) {
592 emit_mov_i(tmp[1], val, ctx);
593 arm_bpf_put_reg32(dst, tmp[1], ctx);
594 } else {
595 emit_mov_i(dst, val, ctx);
596 }
597}
598
599static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx)
600{
601 const s8 *tmp = bpf2a32[TMP_REG_1];
602 const s8 *rd = is_stacked(dst_lo) ? tmp : dst;
603
604 emit_mov_i(rd[1], (u32)val, ctx);
605 emit_mov_i(rd[0], val >> 32, ctx);
606
607 arm_bpf_put_reg64(dst, rd, ctx);
608}
609
610/* Sign extended move */
611static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[],
612 const u32 val, struct jit_ctx *ctx) {
613 u64 val64 = val;
614
615 if (is64 && (val & (1<<31)))
616 val64 |= 0xffffffff00000000ULL;
617 emit_a32_mov_i64(dst, val64, ctx);
618}
619
620static inline void emit_a32_add_r(const u8 dst, const u8 src,
621 const bool is64, const bool hi,
622 struct jit_ctx *ctx) {
623 /* 64 bit :
624 * adds dst_lo, dst_lo, src_lo
625 * adc dst_hi, dst_hi, src_hi
626 * 32 bit :
627 * add dst_lo, dst_lo, src_lo
628 */
629 if (!hi && is64)
630 emit(ARM_ADDS_R(dst, dst, src), ctx);
631 else if (hi && is64)
632 emit(ARM_ADC_R(dst, dst, src), ctx);
633 else
634 emit(ARM_ADD_R(dst, dst, src), ctx);
635}
636
637static inline void emit_a32_sub_r(const u8 dst, const u8 src,
638 const bool is64, const bool hi,
639 struct jit_ctx *ctx) {
640 /* 64 bit :
641 * subs dst_lo, dst_lo, src_lo
642 * sbc dst_hi, dst_hi, src_hi
643 * 32 bit :
644 * sub dst_lo, dst_lo, src_lo
645 */
646 if (!hi && is64)
647 emit(ARM_SUBS_R(dst, dst, src), ctx);
648 else if (hi && is64)
649 emit(ARM_SBC_R(dst, dst, src), ctx);
650 else
651 emit(ARM_SUB_R(dst, dst, src), ctx);
652}
653
654static inline void emit_alu_r(const u8 dst, const u8 src, const bool is64,
655 const bool hi, const u8 op, struct jit_ctx *ctx){
656 switch (BPF_OP(op)) {
657 /* dst = dst + src */
658 case BPF_ADD:
659 emit_a32_add_r(dst, src, is64, hi, ctx);
660 break;
661 /* dst = dst - src */
662 case BPF_SUB:
663 emit_a32_sub_r(dst, src, is64, hi, ctx);
664 break;
665 /* dst = dst | src */
666 case BPF_OR:
667 emit(ARM_ORR_R(dst, dst, src), ctx);
668 break;
669 /* dst = dst & src */
670 case BPF_AND:
671 emit(ARM_AND_R(dst, dst, src), ctx);
672 break;
673 /* dst = dst ^ src */
674 case BPF_XOR:
675 emit(ARM_EOR_R(dst, dst, src), ctx);
676 break;
677 /* dst = dst * src */
678 case BPF_MUL:
679 emit(ARM_MUL(dst, dst, src), ctx);
680 break;
681 /* dst = dst << src */
682 case BPF_LSH:
683 emit(ARM_LSL_R(dst, dst, src), ctx);
684 break;
685 /* dst = dst >> src */
686 case BPF_RSH:
687 emit(ARM_LSR_R(dst, dst, src), ctx);
688 break;
689 /* dst = dst >> src (signed)*/
690 case BPF_ARSH:
691 emit(ARM_MOV_SR(dst, dst, SRTYPE_ASR, src), ctx);
692 break;
693 }
694}
695
696/* ALU operation (32 bit)
697 * dst = dst (op) src
698 */
699static inline void emit_a32_alu_r(const s8 dst, const s8 src,
700 struct jit_ctx *ctx, const bool is64,
701 const bool hi, const u8 op) {
702 const s8 *tmp = bpf2a32[TMP_REG_1];
703 s8 rn, rd;
704
705 rn = arm_bpf_get_reg32(src, tmp[1], ctx);
706 rd = arm_bpf_get_reg32(dst, tmp[0], ctx);
707 /* ALU operation */
708 emit_alu_r(rd, rn, is64, hi, op, ctx);
709 arm_bpf_put_reg32(dst, rd, ctx);
710}
711
712/* ALU operation (64 bit) */
713static inline void emit_a32_alu_r64(const bool is64, const s8 dst[],
714 const s8 src[], struct jit_ctx *ctx,
715 const u8 op) {
716 const s8 *tmp = bpf2a32[TMP_REG_1];
717 const s8 *tmp2 = bpf2a32[TMP_REG_2];
718 const s8 *rd;
719
720 rd = arm_bpf_get_reg64(dst, tmp, ctx);
721 if (is64) {
722 const s8 *rs;
723
724 rs = arm_bpf_get_reg64(src, tmp2, ctx);
725
726 /* ALU operation */
727 emit_alu_r(rd[1], rs[1], true, false, op, ctx);
728 emit_alu_r(rd[0], rs[0], true, true, op, ctx);
729 } else {
730 s8 rs;
731
732 rs = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
733
734 /* ALU operation */
735 emit_alu_r(rd[1], rs, true, false, op, ctx);
736 if (!ctx->prog->aux->verifier_zext)
737 emit_a32_mov_i(rd[0], 0, ctx);
738 }
739
740 arm_bpf_put_reg64(dst, rd, ctx);
741}
742
743/* dst = src (4 bytes)*/
744static inline void emit_a32_mov_r(const s8 dst, const s8 src,
745 struct jit_ctx *ctx) {
746 const s8 *tmp = bpf2a32[TMP_REG_1];
747 s8 rt;
748
749 rt = arm_bpf_get_reg32(src, tmp[0], ctx);
750 arm_bpf_put_reg32(dst, rt, ctx);
751}
752
753/* dst = src */
754static inline void emit_a32_mov_r64(const bool is64, const s8 dst[],
755 const s8 src[],
756 struct jit_ctx *ctx) {
757 if (!is64) {
758 emit_a32_mov_r(dst_lo, src_lo, ctx);
759 if (!ctx->prog->aux->verifier_zext)
760 /* Zero out high 4 bytes */
761 emit_a32_mov_i(dst_hi, 0, ctx);
762 } else if (__LINUX_ARM_ARCH__ < 6 &&
763 ctx->cpu_architecture < CPU_ARCH_ARMv5TE) {
764 /* complete 8 byte move */
765 emit_a32_mov_r(dst_lo, src_lo, ctx);
766 emit_a32_mov_r(dst_hi, src_hi, ctx);
767 } else if (is_stacked(src_lo) && is_stacked(dst_lo)) {
768 const u8 *tmp = bpf2a32[TMP_REG_1];
769
770 emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);
771 emit(ARM_STRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);
772 } else if (is_stacked(src_lo)) {
773 emit(ARM_LDRD_I(dst[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);
774 } else if (is_stacked(dst_lo)) {
775 emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);
776 } else {
777 emit(ARM_MOV_R(dst[0], src[0]), ctx);
778 emit(ARM_MOV_R(dst[1], src[1]), ctx);
779 }
780}
781
782/* Shift operations */
783static inline void emit_a32_alu_i(const s8 dst, const u32 val,
784 struct jit_ctx *ctx, const u8 op) {
785 const s8 *tmp = bpf2a32[TMP_REG_1];
786 s8 rd;
787
788 rd = arm_bpf_get_reg32(dst, tmp[0], ctx);
789
790 /* Do shift operation */
791 switch (op) {
792 case BPF_LSH:
793 emit(ARM_LSL_I(rd, rd, val), ctx);
794 break;
795 case BPF_RSH:
796 emit(ARM_LSR_I(rd, rd, val), ctx);
797 break;
798 case BPF_ARSH:
799 emit(ARM_ASR_I(rd, rd, val), ctx);
800 break;
801 case BPF_NEG:
802 emit(ARM_RSB_I(rd, rd, val), ctx);
803 break;
804 }
805
806 arm_bpf_put_reg32(dst, rd, ctx);
807}
808
809/* dst = ~dst (64 bit) */
810static inline void emit_a32_neg64(const s8 dst[],
811 struct jit_ctx *ctx){
812 const s8 *tmp = bpf2a32[TMP_REG_1];
813 const s8 *rd;
814
815 /* Setup Operand */
816 rd = arm_bpf_get_reg64(dst, tmp, ctx);
817
818 /* Do Negate Operation */
819 emit(ARM_RSBS_I(rd[1], rd[1], 0), ctx);
820 emit(ARM_RSC_I(rd[0], rd[0], 0), ctx);
821
822 arm_bpf_put_reg64(dst, rd, ctx);
823}
824
825/* dst = dst << src */
826static inline void emit_a32_lsh_r64(const s8 dst[], const s8 src[],
827 struct jit_ctx *ctx) {
828 const s8 *tmp = bpf2a32[TMP_REG_1];
829 const s8 *tmp2 = bpf2a32[TMP_REG_2];
830 const s8 *rd;
831 s8 rt;
832
833 /* Setup Operands */
834 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
835 rd = arm_bpf_get_reg64(dst, tmp, ctx);
836
837 /* Do LSH operation */
838 emit(ARM_SUB_I(ARM_IP, rt, 32), ctx);
839 emit(ARM_RSB_I(tmp2[0], rt, 32), ctx);
840 emit(ARM_MOV_SR(ARM_LR, rd[0], SRTYPE_ASL, rt), ctx);
841 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[1], SRTYPE_ASL, ARM_IP), ctx);
842 emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd[1], SRTYPE_LSR, tmp2[0]), ctx);
843 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_ASL, rt), ctx);
844
845 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
846 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
847}
848
849/* dst = dst >> src (signed)*/
850static inline void emit_a32_arsh_r64(const s8 dst[], const s8 src[],
851 struct jit_ctx *ctx) {
852 const s8 *tmp = bpf2a32[TMP_REG_1];
853 const s8 *tmp2 = bpf2a32[TMP_REG_2];
854 const s8 *rd;
855 s8 rt;
856
857 /* Setup Operands */
858 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
859 rd = arm_bpf_get_reg64(dst, tmp, ctx);
860
861 /* Do the ARSH operation */
862 emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
863 emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
864 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx);
865 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx);
866 _emit(ARM_COND_PL,
867 ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx);
868 emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_ASR, rt), ctx);
869
870 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
871 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
872}
873
874/* dst = dst >> src */
875static inline void emit_a32_rsh_r64(const s8 dst[], const s8 src[],
876 struct jit_ctx *ctx) {
877 const s8 *tmp = bpf2a32[TMP_REG_1];
878 const s8 *tmp2 = bpf2a32[TMP_REG_2];
879 const s8 *rd;
880 s8 rt;
881
882 /* Setup Operands */
883 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
884 rd = arm_bpf_get_reg64(dst, tmp, ctx);
885
886 /* Do RSH operation */
887 emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
888 emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
889 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx);
890 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx);
891 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_LSR, tmp2[0]), ctx);
892 emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_LSR, rt), ctx);
893
894 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
895 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
896}
897
898/* dst = dst << val */
899static inline void emit_a32_lsh_i64(const s8 dst[],
900 const u32 val, struct jit_ctx *ctx){
901 const s8 *tmp = bpf2a32[TMP_REG_1];
902 const s8 *tmp2 = bpf2a32[TMP_REG_2];
903 const s8 *rd;
904
905 /* Setup operands */
906 rd = arm_bpf_get_reg64(dst, tmp, ctx);
907
908 /* Do LSH operation */
909 if (val < 32) {
910 emit(ARM_MOV_SI(tmp2[0], rd[0], SRTYPE_ASL, val), ctx);
911 emit(ARM_ORR_SI(rd[0], tmp2[0], rd[1], SRTYPE_LSR, 32 - val), ctx);
912 emit(ARM_MOV_SI(rd[1], rd[1], SRTYPE_ASL, val), ctx);
913 } else {
914 if (val == 32)
915 emit(ARM_MOV_R(rd[0], rd[1]), ctx);
916 else
917 emit(ARM_MOV_SI(rd[0], rd[1], SRTYPE_ASL, val - 32), ctx);
918 emit(ARM_EOR_R(rd[1], rd[1], rd[1]), ctx);
919 }
920
921 arm_bpf_put_reg64(dst, rd, ctx);
922}
923
924/* dst = dst >> val */
925static inline void emit_a32_rsh_i64(const s8 dst[],
926 const u32 val, struct jit_ctx *ctx) {
927 const s8 *tmp = bpf2a32[TMP_REG_1];
928 const s8 *tmp2 = bpf2a32[TMP_REG_2];
929 const s8 *rd;
930
931 /* Setup operands */
932 rd = arm_bpf_get_reg64(dst, tmp, ctx);
933
934 /* Do LSR operation */
935 if (val == 0) {
936 /* An immediate value of 0 encodes a shift amount of 32
937 * for LSR. To shift by 0, don't do anything.
938 */
939 } else if (val < 32) {
940 emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx);
941 emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx);
942 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_LSR, val), ctx);
943 } else if (val == 32) {
944 emit(ARM_MOV_R(rd[1], rd[0]), ctx);
945 emit(ARM_MOV_I(rd[0], 0), ctx);
946 } else {
947 emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_LSR, val - 32), ctx);
948 emit(ARM_MOV_I(rd[0], 0), ctx);
949 }
950
951 arm_bpf_put_reg64(dst, rd, ctx);
952}
953
954/* dst = dst >> val (signed) */
955static inline void emit_a32_arsh_i64(const s8 dst[],
956 const u32 val, struct jit_ctx *ctx){
957 const s8 *tmp = bpf2a32[TMP_REG_1];
958 const s8 *tmp2 = bpf2a32[TMP_REG_2];
959 const s8 *rd;
960
961 /* Setup operands */
962 rd = arm_bpf_get_reg64(dst, tmp, ctx);
963
964 /* Do ARSH operation */
965 if (val == 0) {
966 /* An immediate value of 0 encodes a shift amount of 32
967 * for ASR. To shift by 0, don't do anything.
968 */
969 } else if (val < 32) {
970 emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx);
971 emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx);
972 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, val), ctx);
973 } else if (val == 32) {
974 emit(ARM_MOV_R(rd[1], rd[0]), ctx);
975 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx);
976 } else {
977 emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_ASR, val - 32), ctx);
978 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx);
979 }
980
981 arm_bpf_put_reg64(dst, rd, ctx);
982}
983
984static inline void emit_a32_mul_r64(const s8 dst[], const s8 src[],
985 struct jit_ctx *ctx) {
986 const s8 *tmp = bpf2a32[TMP_REG_1];
987 const s8 *tmp2 = bpf2a32[TMP_REG_2];
988 const s8 *rd, *rt;
989
990 /* Setup operands for multiplication */
991 rd = arm_bpf_get_reg64(dst, tmp, ctx);
992 rt = arm_bpf_get_reg64(src, tmp2, ctx);
993
994 /* Do Multiplication */
995 emit(ARM_MUL(ARM_IP, rd[1], rt[0]), ctx);
996 emit(ARM_MUL(ARM_LR, rd[0], rt[1]), ctx);
997 emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx);
998
999 emit(ARM_UMULL(ARM_IP, rd[0], rd[1], rt[1]), ctx);
1000 emit(ARM_ADD_R(rd[0], ARM_LR, rd[0]), ctx);
1001
1002 arm_bpf_put_reg32(dst_lo, ARM_IP, ctx);
1003 arm_bpf_put_reg32(dst_hi, rd[0], ctx);
1004}
1005
1006static bool is_ldst_imm(s16 off, const u8 size)
1007{
1008 s16 off_max = 0;
1009
1010 switch (size) {
1011 case BPF_B:
1012 case BPF_W:
1013 off_max = 0xfff;
1014 break;
1015 case BPF_H:
1016 off_max = 0xff;
1017 break;
1018 case BPF_DW:
1019 /* Need to make sure off+4 does not overflow. */
1020 off_max = 0xfff - 4;
1021 break;
1022 }
1023 return -off_max <= off && off <= off_max;
1024}
1025
1026/* *(size *)(dst + off) = src */
1027static inline void emit_str_r(const s8 dst, const s8 src[],
1028 s16 off, struct jit_ctx *ctx, const u8 sz){
1029 const s8 *tmp = bpf2a32[TMP_REG_1];
1030 s8 rd;
1031
1032 rd = arm_bpf_get_reg32(dst, tmp[1], ctx);
1033
1034 if (!is_ldst_imm(off, sz)) {
1035 emit_a32_mov_i(tmp[0], off, ctx);
1036 emit(ARM_ADD_R(tmp[0], tmp[0], rd), ctx);
1037 rd = tmp[0];
1038 off = 0;
1039 }
1040 switch (sz) {
1041 case BPF_B:
1042 /* Store a Byte */
1043 emit(ARM_STRB_I(src_lo, rd, off), ctx);
1044 break;
1045 case BPF_H:
1046 /* Store a HalfWord */
1047 emit(ARM_STRH_I(src_lo, rd, off), ctx);
1048 break;
1049 case BPF_W:
1050 /* Store a Word */
1051 emit(ARM_STR_I(src_lo, rd, off), ctx);
1052 break;
1053 case BPF_DW:
1054 /* Store a Double Word */
1055 emit(ARM_STR_I(src_lo, rd, off), ctx);
1056 emit(ARM_STR_I(src_hi, rd, off + 4), ctx);
1057 break;
1058 }
1059}
1060
1061/* dst = *(size*)(src + off) */
1062static inline void emit_ldx_r(const s8 dst[], const s8 src,
1063 s16 off, struct jit_ctx *ctx, const u8 sz){
1064 const s8 *tmp = bpf2a32[TMP_REG_1];
1065 const s8 *rd = is_stacked(dst_lo) ? tmp : dst;
1066 s8 rm = src;
1067
1068 if (!is_ldst_imm(off, sz)) {
1069 emit_a32_mov_i(tmp[0], off, ctx);
1070 emit(ARM_ADD_R(tmp[0], tmp[0], src), ctx);
1071 rm = tmp[0];
1072 off = 0;
1073 } else if (rd[1] == rm) {
1074 emit(ARM_MOV_R(tmp[0], rm), ctx);
1075 rm = tmp[0];
1076 }
1077 switch (sz) {
1078 case BPF_B:
1079 /* Load a Byte */
1080 emit(ARM_LDRB_I(rd[1], rm, off), ctx);
1081 if (!ctx->prog->aux->verifier_zext)
1082 emit_a32_mov_i(rd[0], 0, ctx);
1083 break;
1084 case BPF_H:
1085 /* Load a HalfWord */
1086 emit(ARM_LDRH_I(rd[1], rm, off), ctx);
1087 if (!ctx->prog->aux->verifier_zext)
1088 emit_a32_mov_i(rd[0], 0, ctx);
1089 break;
1090 case BPF_W:
1091 /* Load a Word */
1092 emit(ARM_LDR_I(rd[1], rm, off), ctx);
1093 if (!ctx->prog->aux->verifier_zext)
1094 emit_a32_mov_i(rd[0], 0, ctx);
1095 break;
1096 case BPF_DW:
1097 /* Load a Double Word */
1098 emit(ARM_LDR_I(rd[1], rm, off), ctx);
1099 emit(ARM_LDR_I(rd[0], rm, off + 4), ctx);
1100 break;
1101 }
1102 arm_bpf_put_reg64(dst, rd, ctx);
1103}
1104
1105/* Arithmatic Operation */
1106static inline void emit_ar_r(const u8 rd, const u8 rt, const u8 rm,
1107 const u8 rn, struct jit_ctx *ctx, u8 op,
1108 bool is_jmp64) {
1109 switch (op) {
1110 case BPF_JSET:
1111 if (is_jmp64) {
1112 emit(ARM_AND_R(ARM_IP, rt, rn), ctx);
1113 emit(ARM_AND_R(ARM_LR, rd, rm), ctx);
1114 emit(ARM_ORRS_R(ARM_IP, ARM_LR, ARM_IP), ctx);
1115 } else {
1116 emit(ARM_ANDS_R(ARM_IP, rt, rn), ctx);
1117 }
1118 break;
1119 case BPF_JEQ:
1120 case BPF_JNE:
1121 case BPF_JGT:
1122 case BPF_JGE:
1123 case BPF_JLE:
1124 case BPF_JLT:
1125 if (is_jmp64) {
1126 emit(ARM_CMP_R(rd, rm), ctx);
1127 /* Only compare low halve if high halve are equal. */
1128 _emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx);
1129 } else {
1130 emit(ARM_CMP_R(rt, rn), ctx);
1131 }
1132 break;
1133 case BPF_JSLE:
1134 case BPF_JSGT:
1135 emit(ARM_CMP_R(rn, rt), ctx);
1136 if (is_jmp64)
1137 emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx);
1138 break;
1139 case BPF_JSLT:
1140 case BPF_JSGE:
1141 emit(ARM_CMP_R(rt, rn), ctx);
1142 if (is_jmp64)
1143 emit(ARM_SBCS_R(ARM_IP, rd, rm), ctx);
1144 break;
1145 }
1146}
1147
1148static int out_offset = -1; /* initialized on the first pass of build_body() */
1149static int emit_bpf_tail_call(struct jit_ctx *ctx)
1150{
1151
1152 /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
1153 const s8 *r2 = bpf2a32[BPF_REG_2];
1154 const s8 *r3 = bpf2a32[BPF_REG_3];
1155 const s8 *tmp = bpf2a32[TMP_REG_1];
1156 const s8 *tmp2 = bpf2a32[TMP_REG_2];
1157 const s8 *tcc = bpf2a32[TCALL_CNT];
1158 const s8 *tc;
1159 const int idx0 = ctx->idx;
1160#define cur_offset (ctx->idx - idx0)
1161#define jmp_offset (out_offset - (cur_offset) - 2)
1162 u32 lo, hi;
1163 s8 r_array, r_index;
1164 int off;
1165
1166 /* if (index >= array->map.max_entries)
1167 * goto out;
1168 */
1169 BUILD_BUG_ON(offsetof(struct bpf_array, map.max_entries) >
1170 ARM_INST_LDST__IMM12);
1171 off = offsetof(struct bpf_array, map.max_entries);
1172 r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx);
1173 /* index is 32-bit for arrays */
1174 r_index = arm_bpf_get_reg32(r3[1], tmp2[1], ctx);
1175 /* array->map.max_entries */
1176 emit(ARM_LDR_I(tmp[1], r_array, off), ctx);
1177 /* index >= array->map.max_entries */
1178 emit(ARM_CMP_R(r_index, tmp[1]), ctx);
1179 _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
1180
1181 /* tmp2[0] = array, tmp2[1] = index */
1182
1183 /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
1184 * goto out;
1185 * tail_call_cnt++;
1186 */
1187 lo = (u32)MAX_TAIL_CALL_CNT;
1188 hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32);
1189 tc = arm_bpf_get_reg64(tcc, tmp, ctx);
1190 emit(ARM_CMP_I(tc[0], hi), ctx);
1191 _emit(ARM_COND_EQ, ARM_CMP_I(tc[1], lo), ctx);
1192 _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx);
1193 emit(ARM_ADDS_I(tc[1], tc[1], 1), ctx);
1194 emit(ARM_ADC_I(tc[0], tc[0], 0), ctx);
1195 arm_bpf_put_reg64(tcc, tmp, ctx);
1196
1197 /* prog = array->ptrs[index]
1198 * if (prog == NULL)
1199 * goto out;
1200 */
1201 BUILD_BUG_ON(imm8m(offsetof(struct bpf_array, ptrs)) < 0);
1202 off = imm8m(offsetof(struct bpf_array, ptrs));
1203 emit(ARM_ADD_I(tmp[1], r_array, off), ctx);
1204 emit(ARM_LDR_R_SI(tmp[1], tmp[1], r_index, SRTYPE_ASL, 2), ctx);
1205 emit(ARM_CMP_I(tmp[1], 0), ctx);
1206 _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
1207
1208 /* goto *(prog->bpf_func + prologue_size); */
1209 BUILD_BUG_ON(offsetof(struct bpf_prog, bpf_func) >
1210 ARM_INST_LDST__IMM12);
1211 off = offsetof(struct bpf_prog, bpf_func);
1212 emit(ARM_LDR_I(tmp[1], tmp[1], off), ctx);
1213 emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx);
1214 emit_bx_r(tmp[1], ctx);
1215
1216 /* out: */
1217 if (out_offset == -1)
1218 out_offset = cur_offset;
1219 if (cur_offset != out_offset) {
1220 pr_err_once("tail_call out_offset = %d, expected %d!\n",
1221 cur_offset, out_offset);
1222 return -1;
1223 }
1224 return 0;
1225#undef cur_offset
1226#undef jmp_offset
1227}
1228
1229/* 0xabcd => 0xcdab */
1230static inline void emit_rev16(const u8 rd, const u8 rn, struct jit_ctx *ctx)
1231{
1232#if __LINUX_ARM_ARCH__ < 6
1233 const s8 *tmp2 = bpf2a32[TMP_REG_2];
1234
1235 emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
1236 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 8), ctx);
1237 emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
1238 emit(ARM_ORR_SI(rd, tmp2[0], tmp2[1], SRTYPE_LSL, 8), ctx);
1239#else /* ARMv6+ */
1240 emit(ARM_REV16(rd, rn), ctx);
1241#endif
1242}
1243
1244/* 0xabcdefgh => 0xghefcdab */
1245static inline void emit_rev32(const u8 rd, const u8 rn, struct jit_ctx *ctx)
1246{
1247#if __LINUX_ARM_ARCH__ < 6
1248 const s8 *tmp2 = bpf2a32[TMP_REG_2];
1249
1250 emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
1251 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 24), ctx);
1252 emit(ARM_ORR_SI(ARM_IP, tmp2[0], tmp2[1], SRTYPE_LSL, 24), ctx);
1253
1254 emit(ARM_MOV_SI(tmp2[1], rn, SRTYPE_LSR, 8), ctx);
1255 emit(ARM_AND_I(tmp2[1], tmp2[1], 0xff), ctx);
1256 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 16), ctx);
1257 emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
1258 emit(ARM_MOV_SI(tmp2[0], tmp2[0], SRTYPE_LSL, 8), ctx);
1259 emit(ARM_ORR_SI(tmp2[0], tmp2[0], tmp2[1], SRTYPE_LSL, 16), ctx);
1260 emit(ARM_ORR_R(rd, ARM_IP, tmp2[0]), ctx);
1261
1262#else /* ARMv6+ */
1263 emit(ARM_REV(rd, rn), ctx);
1264#endif
1265}
1266
1267// push the scratch stack register on top of the stack
1268static inline void emit_push_r64(const s8 src[], struct jit_ctx *ctx)
1269{
1270 const s8 *tmp2 = bpf2a32[TMP_REG_2];
1271 const s8 *rt;
1272 u16 reg_set = 0;
1273
1274 rt = arm_bpf_get_reg64(src, tmp2, ctx);
1275
1276 reg_set = (1 << rt[1]) | (1 << rt[0]);
1277 emit(ARM_PUSH(reg_set), ctx);
1278}
1279
1280static void build_prologue(struct jit_ctx *ctx)
1281{
1282 const s8 arm_r0 = bpf2a32[BPF_REG_0][1];
1283 const s8 *bpf_r1 = bpf2a32[BPF_REG_1];
1284 const s8 *bpf_fp = bpf2a32[BPF_REG_FP];
1285 const s8 *tcc = bpf2a32[TCALL_CNT];
1286
1287 /* Save callee saved registers. */
1288#ifdef CONFIG_FRAME_POINTER
1289 u16 reg_set = CALLEE_PUSH_MASK | 1 << ARM_IP | 1 << ARM_PC;
1290 emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx);
1291 emit(ARM_PUSH(reg_set), ctx);
1292 emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx);
1293#else
1294 emit(ARM_PUSH(CALLEE_PUSH_MASK), ctx);
1295 emit(ARM_MOV_R(ARM_FP, ARM_SP), ctx);
1296#endif
1297 /* mov r3, #0 */
1298 /* sub r2, sp, #SCRATCH_SIZE */
1299 emit(ARM_MOV_I(bpf_r1[0], 0), ctx);
1300 emit(ARM_SUB_I(bpf_r1[1], ARM_SP, SCRATCH_SIZE), ctx);
1301
1302 ctx->stack_size = imm8m(STACK_SIZE);
1303
1304 /* Set up function call stack */
1305 emit(ARM_SUB_I(ARM_SP, ARM_SP, ctx->stack_size), ctx);
1306
1307 /* Set up BPF prog stack base register */
1308 emit_a32_mov_r64(true, bpf_fp, bpf_r1, ctx);
1309
1310 /* Initialize Tail Count */
1311 emit(ARM_MOV_I(bpf_r1[1], 0), ctx);
1312 emit_a32_mov_r64(true, tcc, bpf_r1, ctx);
1313
1314 /* Move BPF_CTX to BPF_R1 */
1315 emit(ARM_MOV_R(bpf_r1[1], arm_r0), ctx);
1316
1317 /* end of prologue */
1318}
1319
1320/* restore callee saved registers. */
1321static void build_epilogue(struct jit_ctx *ctx)
1322{
1323#ifdef CONFIG_FRAME_POINTER
1324 /* When using frame pointers, some additional registers need to
1325 * be loaded. */
1326 u16 reg_set = CALLEE_POP_MASK | 1 << ARM_SP;
1327 emit(ARM_SUB_I(ARM_SP, ARM_FP, hweight16(reg_set) * 4), ctx);
1328 emit(ARM_LDM(ARM_SP, reg_set), ctx);
1329#else
1330 /* Restore callee saved registers. */
1331 emit(ARM_MOV_R(ARM_SP, ARM_FP), ctx);
1332 emit(ARM_POP(CALLEE_POP_MASK), ctx);
1333#endif
1334}
1335
1336/*
1337 * Convert an eBPF instruction to native instruction, i.e
1338 * JITs an eBPF instruction.
1339 * Returns :
1340 * 0 - Successfully JITed an 8-byte eBPF instruction
1341 * >0 - Successfully JITed a 16-byte eBPF instruction
1342 * <0 - Failed to JIT.
1343 */
1344static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
1345{
1346 const u8 code = insn->code;
1347 const s8 *dst = bpf2a32[insn->dst_reg];
1348 const s8 *src = bpf2a32[insn->src_reg];
1349 const s8 *tmp = bpf2a32[TMP_REG_1];
1350 const s8 *tmp2 = bpf2a32[TMP_REG_2];
1351 const s16 off = insn->off;
1352 const s32 imm = insn->imm;
1353 const int i = insn - ctx->prog->insnsi;
1354 const bool is64 = BPF_CLASS(code) == BPF_ALU64;
1355 const s8 *rd, *rs;
1356 s8 rd_lo, rt, rm, rn;
1357 s32 jmp_offset;
1358
1359#define check_imm(bits, imm) do { \
1360 if ((imm) >= (1 << ((bits) - 1)) || \
1361 (imm) < -(1 << ((bits) - 1))) { \
1362 pr_info("[%2d] imm=%d(0x%x) out of range\n", \
1363 i, imm, imm); \
1364 return -EINVAL; \
1365 } \
1366} while (0)
1367#define check_imm24(imm) check_imm(24, imm)
1368
1369 switch (code) {
1370 /* ALU operations */
1371
1372 /* dst = src */
1373 case BPF_ALU | BPF_MOV | BPF_K:
1374 case BPF_ALU | BPF_MOV | BPF_X:
1375 case BPF_ALU64 | BPF_MOV | BPF_K:
1376 case BPF_ALU64 | BPF_MOV | BPF_X:
1377 switch (BPF_SRC(code)) {
1378 case BPF_X:
1379 if (imm == 1) {
1380 /* Special mov32 for zext */
1381 emit_a32_mov_i(dst_hi, 0, ctx);
1382 break;
1383 }
1384 emit_a32_mov_r64(is64, dst, src, ctx);
1385 break;
1386 case BPF_K:
1387 /* Sign-extend immediate value to destination reg */
1388 emit_a32_mov_se_i64(is64, dst, imm, ctx);
1389 break;
1390 }
1391 break;
1392 /* dst = dst + src/imm */
1393 /* dst = dst - src/imm */
1394 /* dst = dst | src/imm */
1395 /* dst = dst & src/imm */
1396 /* dst = dst ^ src/imm */
1397 /* dst = dst * src/imm */
1398 /* dst = dst << src */
1399 /* dst = dst >> src */
1400 case BPF_ALU | BPF_ADD | BPF_K:
1401 case BPF_ALU | BPF_ADD | BPF_X:
1402 case BPF_ALU | BPF_SUB | BPF_K:
1403 case BPF_ALU | BPF_SUB | BPF_X:
1404 case BPF_ALU | BPF_OR | BPF_K:
1405 case BPF_ALU | BPF_OR | BPF_X:
1406 case BPF_ALU | BPF_AND | BPF_K:
1407 case BPF_ALU | BPF_AND | BPF_X:
1408 case BPF_ALU | BPF_XOR | BPF_K:
1409 case BPF_ALU | BPF_XOR | BPF_X:
1410 case BPF_ALU | BPF_MUL | BPF_K:
1411 case BPF_ALU | BPF_MUL | BPF_X:
1412 case BPF_ALU | BPF_LSH | BPF_X:
1413 case BPF_ALU | BPF_RSH | BPF_X:
1414 case BPF_ALU | BPF_ARSH | BPF_X:
1415 case BPF_ALU64 | BPF_ADD | BPF_K:
1416 case BPF_ALU64 | BPF_ADD | BPF_X:
1417 case BPF_ALU64 | BPF_SUB | BPF_K:
1418 case BPF_ALU64 | BPF_SUB | BPF_X:
1419 case BPF_ALU64 | BPF_OR | BPF_K:
1420 case BPF_ALU64 | BPF_OR | BPF_X:
1421 case BPF_ALU64 | BPF_AND | BPF_K:
1422 case BPF_ALU64 | BPF_AND | BPF_X:
1423 case BPF_ALU64 | BPF_XOR | BPF_K:
1424 case BPF_ALU64 | BPF_XOR | BPF_X:
1425 switch (BPF_SRC(code)) {
1426 case BPF_X:
1427 emit_a32_alu_r64(is64, dst, src, ctx, BPF_OP(code));
1428 break;
1429 case BPF_K:
1430 /* Move immediate value to the temporary register
1431 * and then do the ALU operation on the temporary
1432 * register as this will sign-extend the immediate
1433 * value into temporary reg and then it would be
1434 * safe to do the operation on it.
1435 */
1436 emit_a32_mov_se_i64(is64, tmp2, imm, ctx);
1437 emit_a32_alu_r64(is64, dst, tmp2, ctx, BPF_OP(code));
1438 break;
1439 }
1440 break;
1441 /* dst = dst / src(imm) */
1442 /* dst = dst % src(imm) */
1443 case BPF_ALU | BPF_DIV | BPF_K:
1444 case BPF_ALU | BPF_DIV | BPF_X:
1445 case BPF_ALU | BPF_MOD | BPF_K:
1446 case BPF_ALU | BPF_MOD | BPF_X:
1447 rd_lo = arm_bpf_get_reg32(dst_lo, tmp2[1], ctx);
1448 switch (BPF_SRC(code)) {
1449 case BPF_X:
1450 rt = arm_bpf_get_reg32(src_lo, tmp2[0], ctx);
1451 break;
1452 case BPF_K:
1453 rt = tmp2[0];
1454 emit_a32_mov_i(rt, imm, ctx);
1455 break;
1456 default:
1457 rt = src_lo;
1458 break;
1459 }
1460 emit_udivmod(rd_lo, rd_lo, rt, ctx, BPF_OP(code));
1461 arm_bpf_put_reg32(dst_lo, rd_lo, ctx);
1462 if (!ctx->prog->aux->verifier_zext)
1463 emit_a32_mov_i(dst_hi, 0, ctx);
1464 break;
1465 case BPF_ALU64 | BPF_DIV | BPF_K:
1466 case BPF_ALU64 | BPF_DIV | BPF_X:
1467 case BPF_ALU64 | BPF_MOD | BPF_K:
1468 case BPF_ALU64 | BPF_MOD | BPF_X:
1469 goto notyet;
1470 /* dst = dst << imm */
1471 /* dst = dst >> imm */
1472 /* dst = dst >> imm (signed) */
1473 case BPF_ALU | BPF_LSH | BPF_K:
1474 case BPF_ALU | BPF_RSH | BPF_K:
1475 case BPF_ALU | BPF_ARSH | BPF_K:
1476 if (unlikely(imm > 31))
1477 return -EINVAL;
1478 if (imm)
1479 emit_a32_alu_i(dst_lo, imm, ctx, BPF_OP(code));
1480 if (!ctx->prog->aux->verifier_zext)
1481 emit_a32_mov_i(dst_hi, 0, ctx);
1482 break;
1483 /* dst = dst << imm */
1484 case BPF_ALU64 | BPF_LSH | BPF_K:
1485 if (unlikely(imm > 63))
1486 return -EINVAL;
1487 emit_a32_lsh_i64(dst, imm, ctx);
1488 break;
1489 /* dst = dst >> imm */
1490 case BPF_ALU64 | BPF_RSH | BPF_K:
1491 if (unlikely(imm > 63))
1492 return -EINVAL;
1493 emit_a32_rsh_i64(dst, imm, ctx);
1494 break;
1495 /* dst = dst << src */
1496 case BPF_ALU64 | BPF_LSH | BPF_X:
1497 emit_a32_lsh_r64(dst, src, ctx);
1498 break;
1499 /* dst = dst >> src */
1500 case BPF_ALU64 | BPF_RSH | BPF_X:
1501 emit_a32_rsh_r64(dst, src, ctx);
1502 break;
1503 /* dst = dst >> src (signed) */
1504 case BPF_ALU64 | BPF_ARSH | BPF_X:
1505 emit_a32_arsh_r64(dst, src, ctx);
1506 break;
1507 /* dst = dst >> imm (signed) */
1508 case BPF_ALU64 | BPF_ARSH | BPF_K:
1509 if (unlikely(imm > 63))
1510 return -EINVAL;
1511 emit_a32_arsh_i64(dst, imm, ctx);
1512 break;
1513 /* dst = ~dst */
1514 case BPF_ALU | BPF_NEG:
1515 emit_a32_alu_i(dst_lo, 0, ctx, BPF_OP(code));
1516 if (!ctx->prog->aux->verifier_zext)
1517 emit_a32_mov_i(dst_hi, 0, ctx);
1518 break;
1519 /* dst = ~dst (64 bit) */
1520 case BPF_ALU64 | BPF_NEG:
1521 emit_a32_neg64(dst, ctx);
1522 break;
1523 /* dst = dst * src/imm */
1524 case BPF_ALU64 | BPF_MUL | BPF_X:
1525 case BPF_ALU64 | BPF_MUL | BPF_K:
1526 switch (BPF_SRC(code)) {
1527 case BPF_X:
1528 emit_a32_mul_r64(dst, src, ctx);
1529 break;
1530 case BPF_K:
1531 /* Move immediate value to the temporary register
1532 * and then do the multiplication on it as this
1533 * will sign-extend the immediate value into temp
1534 * reg then it would be safe to do the operation
1535 * on it.
1536 */
1537 emit_a32_mov_se_i64(is64, tmp2, imm, ctx);
1538 emit_a32_mul_r64(dst, tmp2, ctx);
1539 break;
1540 }
1541 break;
1542 /* dst = htole(dst) */
1543 /* dst = htobe(dst) */
1544 case BPF_ALU | BPF_END | BPF_FROM_LE:
1545 case BPF_ALU | BPF_END | BPF_FROM_BE:
1546 rd = arm_bpf_get_reg64(dst, tmp, ctx);
1547 if (BPF_SRC(code) == BPF_FROM_LE)
1548 goto emit_bswap_uxt;
1549 switch (imm) {
1550 case 16:
1551 emit_rev16(rd[1], rd[1], ctx);
1552 goto emit_bswap_uxt;
1553 case 32:
1554 emit_rev32(rd[1], rd[1], ctx);
1555 goto emit_bswap_uxt;
1556 case 64:
1557 emit_rev32(ARM_LR, rd[1], ctx);
1558 emit_rev32(rd[1], rd[0], ctx);
1559 emit(ARM_MOV_R(rd[0], ARM_LR), ctx);
1560 break;
1561 }
1562 goto exit;
1563emit_bswap_uxt:
1564 switch (imm) {
1565 case 16:
1566 /* zero-extend 16 bits into 64 bits */
1567#if __LINUX_ARM_ARCH__ < 6
1568 emit_a32_mov_i(tmp2[1], 0xffff, ctx);
1569 emit(ARM_AND_R(rd[1], rd[1], tmp2[1]), ctx);
1570#else /* ARMv6+ */
1571 emit(ARM_UXTH(rd[1], rd[1]), ctx);
1572#endif
1573 if (!ctx->prog->aux->verifier_zext)
1574 emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx);
1575 break;
1576 case 32:
1577 /* zero-extend 32 bits into 64 bits */
1578 if (!ctx->prog->aux->verifier_zext)
1579 emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx);
1580 break;
1581 case 64:
1582 /* nop */
1583 break;
1584 }
1585exit:
1586 arm_bpf_put_reg64(dst, rd, ctx);
1587 break;
1588 /* dst = imm64 */
1589 case BPF_LD | BPF_IMM | BPF_DW:
1590 {
1591 u64 val = (u32)imm | (u64)insn[1].imm << 32;
1592
1593 emit_a32_mov_i64(dst, val, ctx);
1594
1595 return 1;
1596 }
1597 /* LDX: dst = *(size *)(src + off) */
1598 case BPF_LDX | BPF_MEM | BPF_W:
1599 case BPF_LDX | BPF_MEM | BPF_H:
1600 case BPF_LDX | BPF_MEM | BPF_B:
1601 case BPF_LDX | BPF_MEM | BPF_DW:
1602 rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
1603 emit_ldx_r(dst, rn, off, ctx, BPF_SIZE(code));
1604 break;
1605 /* ST: *(size *)(dst + off) = imm */
1606 case BPF_ST | BPF_MEM | BPF_W:
1607 case BPF_ST | BPF_MEM | BPF_H:
1608 case BPF_ST | BPF_MEM | BPF_B:
1609 case BPF_ST | BPF_MEM | BPF_DW:
1610 switch (BPF_SIZE(code)) {
1611 case BPF_DW:
1612 /* Sign-extend immediate value into temp reg */
1613 emit_a32_mov_se_i64(true, tmp2, imm, ctx);
1614 break;
1615 case BPF_W:
1616 case BPF_H:
1617 case BPF_B:
1618 emit_a32_mov_i(tmp2[1], imm, ctx);
1619 break;
1620 }
1621 emit_str_r(dst_lo, tmp2, off, ctx, BPF_SIZE(code));
1622 break;
1623 /* STX XADD: lock *(u32 *)(dst + off) += src */
1624 case BPF_STX | BPF_XADD | BPF_W:
1625 /* STX XADD: lock *(u64 *)(dst + off) += src */
1626 case BPF_STX | BPF_XADD | BPF_DW:
1627 goto notyet;
1628 /* STX: *(size *)(dst + off) = src */
1629 case BPF_STX | BPF_MEM | BPF_W:
1630 case BPF_STX | BPF_MEM | BPF_H:
1631 case BPF_STX | BPF_MEM | BPF_B:
1632 case BPF_STX | BPF_MEM | BPF_DW:
1633 rs = arm_bpf_get_reg64(src, tmp2, ctx);
1634 emit_str_r(dst_lo, rs, off, ctx, BPF_SIZE(code));
1635 break;
1636 /* PC += off if dst == src */
1637 /* PC += off if dst > src */
1638 /* PC += off if dst >= src */
1639 /* PC += off if dst < src */
1640 /* PC += off if dst <= src */
1641 /* PC += off if dst != src */
1642 /* PC += off if dst > src (signed) */
1643 /* PC += off if dst >= src (signed) */
1644 /* PC += off if dst < src (signed) */
1645 /* PC += off if dst <= src (signed) */
1646 /* PC += off if dst & src */
1647 case BPF_JMP | BPF_JEQ | BPF_X:
1648 case BPF_JMP | BPF_JGT | BPF_X:
1649 case BPF_JMP | BPF_JGE | BPF_X:
1650 case BPF_JMP | BPF_JNE | BPF_X:
1651 case BPF_JMP | BPF_JSGT | BPF_X:
1652 case BPF_JMP | BPF_JSGE | BPF_X:
1653 case BPF_JMP | BPF_JSET | BPF_X:
1654 case BPF_JMP | BPF_JLE | BPF_X:
1655 case BPF_JMP | BPF_JLT | BPF_X:
1656 case BPF_JMP | BPF_JSLT | BPF_X:
1657 case BPF_JMP | BPF_JSLE | BPF_X:
1658 case BPF_JMP32 | BPF_JEQ | BPF_X:
1659 case BPF_JMP32 | BPF_JGT | BPF_X:
1660 case BPF_JMP32 | BPF_JGE | BPF_X:
1661 case BPF_JMP32 | BPF_JNE | BPF_X:
1662 case BPF_JMP32 | BPF_JSGT | BPF_X:
1663 case BPF_JMP32 | BPF_JSGE | BPF_X:
1664 case BPF_JMP32 | BPF_JSET | BPF_X:
1665 case BPF_JMP32 | BPF_JLE | BPF_X:
1666 case BPF_JMP32 | BPF_JLT | BPF_X:
1667 case BPF_JMP32 | BPF_JSLT | BPF_X:
1668 case BPF_JMP32 | BPF_JSLE | BPF_X:
1669 /* Setup source registers */
1670 rm = arm_bpf_get_reg32(src_hi, tmp2[0], ctx);
1671 rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
1672 goto go_jmp;
1673 /* PC += off if dst == imm */
1674 /* PC += off if dst > imm */
1675 /* PC += off if dst >= imm */
1676 /* PC += off if dst < imm */
1677 /* PC += off if dst <= imm */
1678 /* PC += off if dst != imm */
1679 /* PC += off if dst > imm (signed) */
1680 /* PC += off if dst >= imm (signed) */
1681 /* PC += off if dst < imm (signed) */
1682 /* PC += off if dst <= imm (signed) */
1683 /* PC += off if dst & imm */
1684 case BPF_JMP | BPF_JEQ | BPF_K:
1685 case BPF_JMP | BPF_JGT | BPF_K:
1686 case BPF_JMP | BPF_JGE | BPF_K:
1687 case BPF_JMP | BPF_JNE | BPF_K:
1688 case BPF_JMP | BPF_JSGT | BPF_K:
1689 case BPF_JMP | BPF_JSGE | BPF_K:
1690 case BPF_JMP | BPF_JSET | BPF_K:
1691 case BPF_JMP | BPF_JLT | BPF_K:
1692 case BPF_JMP | BPF_JLE | BPF_K:
1693 case BPF_JMP | BPF_JSLT | BPF_K:
1694 case BPF_JMP | BPF_JSLE | BPF_K:
1695 case BPF_JMP32 | BPF_JEQ | BPF_K:
1696 case BPF_JMP32 | BPF_JGT | BPF_K:
1697 case BPF_JMP32 | BPF_JGE | BPF_K:
1698 case BPF_JMP32 | BPF_JNE | BPF_K:
1699 case BPF_JMP32 | BPF_JSGT | BPF_K:
1700 case BPF_JMP32 | BPF_JSGE | BPF_K:
1701 case BPF_JMP32 | BPF_JSET | BPF_K:
1702 case BPF_JMP32 | BPF_JLT | BPF_K:
1703 case BPF_JMP32 | BPF_JLE | BPF_K:
1704 case BPF_JMP32 | BPF_JSLT | BPF_K:
1705 case BPF_JMP32 | BPF_JSLE | BPF_K:
1706 if (off == 0)
1707 break;
1708 rm = tmp2[0];
1709 rn = tmp2[1];
1710 /* Sign-extend immediate value */
1711 emit_a32_mov_se_i64(true, tmp2, imm, ctx);
1712go_jmp:
1713 /* Setup destination register */
1714 rd = arm_bpf_get_reg64(dst, tmp, ctx);
1715
1716 /* Check for the condition */
1717 emit_ar_r(rd[0], rd[1], rm, rn, ctx, BPF_OP(code),
1718 BPF_CLASS(code) == BPF_JMP);
1719
1720 /* Setup JUMP instruction */
1721 jmp_offset = bpf2a32_offset(i+off, i, ctx);
1722 switch (BPF_OP(code)) {
1723 case BPF_JNE:
1724 case BPF_JSET:
1725 _emit(ARM_COND_NE, ARM_B(jmp_offset), ctx);
1726 break;
1727 case BPF_JEQ:
1728 _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
1729 break;
1730 case BPF_JGT:
1731 _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx);
1732 break;
1733 case BPF_JGE:
1734 _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
1735 break;
1736 case BPF_JSGT:
1737 _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx);
1738 break;
1739 case BPF_JSGE:
1740 _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx);
1741 break;
1742 case BPF_JLE:
1743 _emit(ARM_COND_LS, ARM_B(jmp_offset), ctx);
1744 break;
1745 case BPF_JLT:
1746 _emit(ARM_COND_CC, ARM_B(jmp_offset), ctx);
1747 break;
1748 case BPF_JSLT:
1749 _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx);
1750 break;
1751 case BPF_JSLE:
1752 _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx);
1753 break;
1754 }
1755 break;
1756 /* JMP OFF */
1757 case BPF_JMP | BPF_JA:
1758 {
1759 if (off == 0)
1760 break;
1761 jmp_offset = bpf2a32_offset(i+off, i, ctx);
1762 check_imm24(jmp_offset);
1763 emit(ARM_B(jmp_offset), ctx);
1764 break;
1765 }
1766 /* tail call */
1767 case BPF_JMP | BPF_TAIL_CALL:
1768 if (emit_bpf_tail_call(ctx))
1769 return -EFAULT;
1770 break;
1771 /* function call */
1772 case BPF_JMP | BPF_CALL:
1773 {
1774 const s8 *r0 = bpf2a32[BPF_REG_0];
1775 const s8 *r1 = bpf2a32[BPF_REG_1];
1776 const s8 *r2 = bpf2a32[BPF_REG_2];
1777 const s8 *r3 = bpf2a32[BPF_REG_3];
1778 const s8 *r4 = bpf2a32[BPF_REG_4];
1779 const s8 *r5 = bpf2a32[BPF_REG_5];
1780 const u32 func = (u32)__bpf_call_base + (u32)imm;
1781
1782 emit_a32_mov_r64(true, r0, r1, ctx);
1783 emit_a32_mov_r64(true, r1, r2, ctx);
1784 emit_push_r64(r5, ctx);
1785 emit_push_r64(r4, ctx);
1786 emit_push_r64(r3, ctx);
1787
1788 emit_a32_mov_i(tmp[1], func, ctx);
1789 emit_blx_r(tmp[1], ctx);
1790
1791 emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(24)), ctx); // callee clean
1792 break;
1793 }
1794 /* function return */
1795 case BPF_JMP | BPF_EXIT:
1796 /* Optimization: when last instruction is EXIT
1797 * simply fallthrough to epilogue.
1798 */
1799 if (i == ctx->prog->len - 1)
1800 break;
1801 jmp_offset = epilogue_offset(ctx);
1802 check_imm24(jmp_offset);
1803 emit(ARM_B(jmp_offset), ctx);
1804 break;
1805notyet:
1806 pr_info_once("*** NOT YET: opcode %02x ***\n", code);
1807 return -EFAULT;
1808 default:
1809 pr_err_once("unknown opcode %02x\n", code);
1810 return -EINVAL;
1811 }
1812
1813 if (ctx->flags & FLAG_IMM_OVERFLOW)
1814 /*
1815 * this instruction generated an overflow when
1816 * trying to access the literal pool, so
1817 * delegate this filter to the kernel interpreter.
1818 */
1819 return -1;
1820 return 0;
1821}
1822
1823static int build_body(struct jit_ctx *ctx)
1824{
1825 const struct bpf_prog *prog = ctx->prog;
1826 unsigned int i;
1827
1828 for (i = 0; i < prog->len; i++) {
1829 const struct bpf_insn *insn = &(prog->insnsi[i]);
1830 int ret;
1831
1832 ret = build_insn(insn, ctx);
1833
1834 /* It's used with loading the 64 bit immediate value. */
1835 if (ret > 0) {
1836 i++;
1837 if (ctx->target == NULL)
1838 ctx->offsets[i] = ctx->idx;
1839 continue;
1840 }
1841
1842 if (ctx->target == NULL)
1843 ctx->offsets[i] = ctx->idx;
1844
1845 /* If unsuccesfull, return with error code */
1846 if (ret)
1847 return ret;
1848 }
1849 return 0;
1850}
1851
1852static int validate_code(struct jit_ctx *ctx)
1853{
1854 int i;
1855
1856 for (i = 0; i < ctx->idx; i++) {
1857 if (ctx->target[i] == __opcode_to_mem_arm(ARM_INST_UDF))
1858 return -1;
1859 }
1860
1861 return 0;
1862}
1863
1864void bpf_jit_compile(struct bpf_prog *prog)
1865{
1866 /* Nothing to do here. We support Internal BPF. */
1867}
1868
1869bool bpf_jit_needs_zext(void)
1870{
1871 return true;
1872}
1873
1874struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
1875{
1876 struct bpf_prog *tmp, *orig_prog = prog;
1877 struct bpf_binary_header *header;
1878 bool tmp_blinded = false;
1879 struct jit_ctx ctx;
1880 unsigned int tmp_idx;
1881 unsigned int image_size;
1882 u8 *image_ptr;
1883
1884 /* If BPF JIT was not enabled then we must fall back to
1885 * the interpreter.
1886 */
1887 if (!prog->jit_requested)
1888 return orig_prog;
1889
1890 /* If constant blinding was enabled and we failed during blinding
1891 * then we must fall back to the interpreter. Otherwise, we save
1892 * the new JITed code.
1893 */
1894 tmp = bpf_jit_blind_constants(prog);
1895
1896 if (IS_ERR(tmp))
1897 return orig_prog;
1898 if (tmp != prog) {
1899 tmp_blinded = true;
1900 prog = tmp;
1901 }
1902
1903 memset(&ctx, 0, sizeof(ctx));
1904 ctx.prog = prog;
1905 ctx.cpu_architecture = cpu_architecture();
1906
1907 /* Not able to allocate memory for offsets[] , then
1908 * we must fall back to the interpreter
1909 */
1910 ctx.offsets = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
1911 if (ctx.offsets == NULL) {
1912 prog = orig_prog;
1913 goto out;
1914 }
1915
1916 /* 1) fake pass to find in the length of the JITed code,
1917 * to compute ctx->offsets and other context variables
1918 * needed to compute final JITed code.
1919 * Also, calculate random starting pointer/start of JITed code
1920 * which is prefixed by random number of fault instructions.
1921 *
1922 * If the first pass fails then there is no chance of it
1923 * being successful in the second pass, so just fall back
1924 * to the interpreter.
1925 */
1926 if (build_body(&ctx)) {
1927 prog = orig_prog;
1928 goto out_off;
1929 }
1930
1931 tmp_idx = ctx.idx;
1932 build_prologue(&ctx);
1933 ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
1934
1935 ctx.epilogue_offset = ctx.idx;
1936
1937#if __LINUX_ARM_ARCH__ < 7
1938 tmp_idx = ctx.idx;
1939 build_epilogue(&ctx);
1940 ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4;
1941
1942 ctx.idx += ctx.imm_count;
1943 if (ctx.imm_count) {
1944 ctx.imms = kcalloc(ctx.imm_count, sizeof(u32), GFP_KERNEL);
1945 if (ctx.imms == NULL) {
1946 prog = orig_prog;
1947 goto out_off;
1948 }
1949 }
1950#else
1951 /* there's nothing about the epilogue on ARMv7 */
1952 build_epilogue(&ctx);
1953#endif
1954 /* Now we can get the actual image size of the JITed arm code.
1955 * Currently, we are not considering the THUMB-2 instructions
1956 * for jit, although it can decrease the size of the image.
1957 *
1958 * As each arm instruction is of length 32bit, we are translating
1959 * number of JITed intructions into the size required to store these
1960 * JITed code.
1961 */
1962 image_size = sizeof(u32) * ctx.idx;
1963
1964 /* Now we know the size of the structure to make */
1965 header = bpf_jit_binary_alloc(image_size, &image_ptr,
1966 sizeof(u32), jit_fill_hole);
1967 /* Not able to allocate memory for the structure then
1968 * we must fall back to the interpretation
1969 */
1970 if (header == NULL) {
1971 prog = orig_prog;
1972 goto out_imms;
1973 }
1974
1975 /* 2.) Actual pass to generate final JIT code */
1976 ctx.target = (u32 *) image_ptr;
1977 ctx.idx = 0;
1978
1979 build_prologue(&ctx);
1980
1981 /* If building the body of the JITed code fails somehow,
1982 * we fall back to the interpretation.
1983 */
1984 if (build_body(&ctx) < 0) {
1985 image_ptr = NULL;
1986 bpf_jit_binary_free(header);
1987 prog = orig_prog;
1988 goto out_imms;
1989 }
1990 build_epilogue(&ctx);
1991
1992 /* 3.) Extra pass to validate JITed Code */
1993 if (validate_code(&ctx)) {
1994 image_ptr = NULL;
1995 bpf_jit_binary_free(header);
1996 prog = orig_prog;
1997 goto out_imms;
1998 }
1999 flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
2000
2001 if (bpf_jit_enable > 1)
2002 /* there are 2 passes here */
2003 bpf_jit_dump(prog->len, image_size, 2, ctx.target);
2004
2005 bpf_jit_binary_lock_ro(header);
2006 prog->bpf_func = (void *)ctx.target;
2007 prog->jited = 1;
2008 prog->jited_len = image_size;
2009
2010out_imms:
2011#if __LINUX_ARM_ARCH__ < 7
2012 if (ctx.imm_count)
2013 kfree(ctx.imms);
2014#endif
2015out_off:
2016 kfree(ctx.offsets);
2017out:
2018 if (tmp_blinded)
2019 bpf_jit_prog_release_other(prog, prog == orig_prog ?
2020 tmp : orig_prog);
2021 return prog;
2022}
2023