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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / arch / arm64 / net / bpf_jit_comp.c
bloba93350451e8ece754a2f565764d47505e48b85ef
1 /*
2 * BPF JIT compiler for ARM64
3 *
4 * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #define pr_fmt(fmt) "bpf_jit: " fmt
20
21 #include <linux/bpf.h>
22 #include <linux/filter.h>
23 #include <linux/printk.h>
24 #include <linux/skbuff.h>
25 #include <linux/slab.h>
26
27 #include <asm/byteorder.h>
28 #include <asm/cacheflush.h>
29 #include <asm/debug-monitors.h>
30 #include <asm/set_memory.h>
31
32 #include "bpf_jit.h"
33
34 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
35 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
36 #define TCALL_CNT (MAX_BPF_JIT_REG + 2)
37 #define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
38
39 /* Map BPF registers to A64 registers */
40 static const int bpf2a64[] = {
41 /* return value from in-kernel function, and exit value from eBPF */
42 [BPF_REG_0] = A64_R(7),
43 /* arguments from eBPF program to in-kernel function */
44 [BPF_REG_1] = A64_R(0),
45 [BPF_REG_2] = A64_R(1),
46 [BPF_REG_3] = A64_R(2),
47 [BPF_REG_4] = A64_R(3),
48 [BPF_REG_5] = A64_R(4),
49 /* callee saved registers that in-kernel function will preserve */
50 [BPF_REG_6] = A64_R(19),
51 [BPF_REG_7] = A64_R(20),
52 [BPF_REG_8] = A64_R(21),
53 [BPF_REG_9] = A64_R(22),
54 /* read-only frame pointer to access stack */
55 [BPF_REG_FP] = A64_R(25),
56 /* temporary registers for internal BPF JIT */
57 [TMP_REG_1] = A64_R(10),
58 [TMP_REG_2] = A64_R(11),
59 [TMP_REG_3] = A64_R(12),
60 /* tail_call_cnt */
61 [TCALL_CNT] = A64_R(26),
62 /* temporary register for blinding constants */
63 [BPF_REG_AX] = A64_R(9),
64 };
65
66 struct jit_ctx {
67 const struct bpf_prog *prog;
68 int idx;
69 int epilogue_offset;
70 int *offset;
71 __le32 *image;
72 u32 stack_size;
73 };
74
75 static inline void emit(const u32 insn, struct jit_ctx *ctx)
76 {
77 if (ctx->image != NULL)
78 ctx->image[ctx->idx] = cpu_to_le32(insn);
79
80 ctx->idx++;
81 }
82
83 static inline void emit_a64_mov_i64(const int reg, const u64 val,
84 struct jit_ctx *ctx)
85 {
86 u64 tmp = val;
87 int shift = 0;
88
89 emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
90 tmp >>= 16;
91 shift += 16;
92 while (tmp) {
93 if (tmp & 0xffff)
94 emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
95 tmp >>= 16;
96 shift += 16;
97 }
98 }
99
100 static inline void emit_addr_mov_i64(const int reg, const u64 val,
101 struct jit_ctx *ctx)
102 {
103 u64 tmp = val;
104 int shift = 0;
105
106 emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
107 for (;shift < 48;) {
108 tmp >>= 16;
109 shift += 16;
110 emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
111 }
112 }
113
114 static inline void emit_a64_mov_i(const int is64, const int reg,
115 const s32 val, struct jit_ctx *ctx)
116 {
117 u16 hi = val >> 16;
118 u16 lo = val & 0xffff;
119
120 if (hi & 0x8000) {
121 if (hi == 0xffff) {
122 emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
123 } else {
124 emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
125 emit(A64_MOVK(is64, reg, lo, 0), ctx);
126 }
127 } else {
128 emit(A64_MOVZ(is64, reg, lo, 0), ctx);
129 if (hi)
130 emit(A64_MOVK(is64, reg, hi, 16), ctx);
131 }
132 }
133
134 static inline int bpf2a64_offset(int bpf_to, int bpf_from,
135 const struct jit_ctx *ctx)
136 {
137 int to = ctx->offset[bpf_to];
138 /* -1 to account for the Branch instruction */
139 int from = ctx->offset[bpf_from] - 1;
140
141 return to - from;
142 }
143
144 static void jit_fill_hole(void *area, unsigned int size)
145 {
146 __le32 *ptr;
147 /* We are guaranteed to have aligned memory. */
148 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
149 *ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT);
150 }
151
152 static inline int epilogue_offset(const struct jit_ctx *ctx)
153 {
154 int to = ctx->epilogue_offset;
155 int from = ctx->idx;
156
157 return to - from;
158 }
159
160 /* Stack must be multiples of 16B */
161 #define STACK_ALIGN(sz) (((sz) + 15) & ~15)
162
163 /* Tail call offset to jump into */
164 #define PROLOGUE_OFFSET 7
165
166 static int build_prologue(struct jit_ctx *ctx)
167 {
168 const struct bpf_prog *prog = ctx->prog;
169 const u8 r6 = bpf2a64[BPF_REG_6];
170 const u8 r7 = bpf2a64[BPF_REG_7];
171 const u8 r8 = bpf2a64[BPF_REG_8];
172 const u8 r9 = bpf2a64[BPF_REG_9];
173 const u8 fp = bpf2a64[BPF_REG_FP];
174 const u8 tcc = bpf2a64[TCALL_CNT];
175 const int idx0 = ctx->idx;
176 int cur_offset;
177
178 /*
179 * BPF prog stack layout
180 *
181 * high
182 * original A64_SP => 0:+-----+ BPF prologue
183 * |FP/LR|
184 * current A64_FP => -16:+-----+
185 * | ... | callee saved registers
186 * BPF fp register => -64:+-----+ <= (BPF_FP)
187 * | |
188 * | ... | BPF prog stack
189 * | |
190 * +-----+ <= (BPF_FP - prog->aux->stack_depth)
191 * |RSVD | JIT scratchpad
192 * current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size)
193 * | |
194 * | ... | Function call stack
195 * | |
196 * +-----+
197 * low
198 *
199 */
200
201 /* Save FP and LR registers to stay align with ARM64 AAPCS */
202 emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
203 emit(A64_MOV(1, A64_FP, A64_SP), ctx);
204
205 /* Save callee-saved registers */
206 emit(A64_PUSH(r6, r7, A64_SP), ctx);
207 emit(A64_PUSH(r8, r9, A64_SP), ctx);
208 emit(A64_PUSH(fp, tcc, A64_SP), ctx);
209
210 /* Set up BPF prog stack base register */
211 emit(A64_MOV(1, fp, A64_SP), ctx);
212
213 /* Initialize tail_call_cnt */
214 emit(A64_MOVZ(1, tcc, 0, 0), ctx);
215
216 cur_offset = ctx->idx - idx0;
217 if (cur_offset != PROLOGUE_OFFSET) {
218 pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
219 cur_offset, PROLOGUE_OFFSET);
220 return -1;
221 }
222
223 /* 4 byte extra for skb_copy_bits buffer */
224 ctx->stack_size = prog->aux->stack_depth + 4;
225 ctx->stack_size = STACK_ALIGN(ctx->stack_size);
226
227 /* Set up function call stack */
228 emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
229 return 0;
230 }
231
232 static int out_offset = -1; /* initialized on the first pass of build_body() */
233 static int emit_bpf_tail_call(struct jit_ctx *ctx)
234 {
235 /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
236 const u8 r2 = bpf2a64[BPF_REG_2];
237 const u8 r3 = bpf2a64[BPF_REG_3];
238
239 const u8 tmp = bpf2a64[TMP_REG_1];
240 const u8 prg = bpf2a64[TMP_REG_2];
241 const u8 tcc = bpf2a64[TCALL_CNT];
242 const int idx0 = ctx->idx;
243 #define cur_offset (ctx->idx - idx0)
244 #define jmp_offset (out_offset - (cur_offset))
245 size_t off;
246
247 /* if (index >= array->map.max_entries)
248 * goto out;
249 */
250 off = offsetof(struct bpf_array, map.max_entries);
251 emit_a64_mov_i64(tmp, off, ctx);
252 emit(A64_LDR32(tmp, r2, tmp), ctx);
253 emit(A64_MOV(0, r3, r3), ctx);
254 emit(A64_CMP(0, r3, tmp), ctx);
255 emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
256
257 /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
258 * goto out;
259 * tail_call_cnt++;
260 */
261 emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
262 emit(A64_CMP(1, tcc, tmp), ctx);
263 emit(A64_B_(A64_COND_HI, jmp_offset), ctx);
264 emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
265
266 /* prog = array->ptrs[index];
267 * if (prog == NULL)
268 * goto out;
269 */
270 off = offsetof(struct bpf_array, ptrs);
271 emit_a64_mov_i64(tmp, off, ctx);
272 emit(A64_ADD(1, tmp, r2, tmp), ctx);
273 emit(A64_LSL(1, prg, r3, 3), ctx);
274 emit(A64_LDR64(prg, tmp, prg), ctx);
275 emit(A64_CBZ(1, prg, jmp_offset), ctx);
276
277 /* goto *(prog->bpf_func + prologue_offset); */
278 off = offsetof(struct bpf_prog, bpf_func);
279 emit_a64_mov_i64(tmp, off, ctx);
280 emit(A64_LDR64(tmp, prg, tmp), ctx);
281 emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
282 emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
283 emit(A64_BR(tmp), ctx);
284
285 /* out: */
286 if (out_offset == -1)
287 out_offset = cur_offset;
288 if (cur_offset != out_offset) {
289 pr_err_once("tail_call out_offset = %d, expected %d!\n",
290 cur_offset, out_offset);
291 return -1;
292 }
293 return 0;
294 #undef cur_offset
295 #undef jmp_offset
296 }
297
298 static void build_epilogue(struct jit_ctx *ctx)
299 {
300 const u8 r0 = bpf2a64[BPF_REG_0];
301 const u8 r6 = bpf2a64[BPF_REG_6];
302 const u8 r7 = bpf2a64[BPF_REG_7];
303 const u8 r8 = bpf2a64[BPF_REG_8];
304 const u8 r9 = bpf2a64[BPF_REG_9];
305 const u8 fp = bpf2a64[BPF_REG_FP];
306
307 /* We're done with BPF stack */
308 emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
309
310 /* Restore fs (x25) and x26 */
311 emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
312
313 /* Restore callee-saved register */
314 emit(A64_POP(r8, r9, A64_SP), ctx);
315 emit(A64_POP(r6, r7, A64_SP), ctx);
316
317 /* Restore FP/LR registers */
318 emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
319
320 /* Set return value */
321 emit(A64_MOV(1, A64_R(0), r0), ctx);
322
323 emit(A64_RET(A64_LR), ctx);
324 }
325
326 /* JITs an eBPF instruction.
327 * Returns:
328 * 0 - successfully JITed an 8-byte eBPF instruction.
329 * >0 - successfully JITed a 16-byte eBPF instruction.
330 * <0 - failed to JIT.
331 */
332 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
333 {
334 const u8 code = insn->code;
335 const u8 dst = bpf2a64[insn->dst_reg];
336 const u8 src = bpf2a64[insn->src_reg];
337 const u8 tmp = bpf2a64[TMP_REG_1];
338 const u8 tmp2 = bpf2a64[TMP_REG_2];
339 const u8 tmp3 = bpf2a64[TMP_REG_3];
340 const s16 off = insn->off;
341 const s32 imm = insn->imm;
342 const int i = insn - ctx->prog->insnsi;
343 const bool is64 = BPF_CLASS(code) == BPF_ALU64;
344 const bool isdw = BPF_SIZE(code) == BPF_DW;
345 u8 jmp_cond;
346 s32 jmp_offset;
347
348 #define check_imm(bits, imm) do { \
349 if ((((imm) > 0) && ((imm) >> (bits))) || \
350 (((imm) < 0) && (~(imm) >> (bits)))) { \
351 pr_info("[%2d] imm=%d(0x%x) out of range\n", \
352 i, imm, imm); \
353 return -EINVAL; \
354 } \
355 } while (0)
356 #define check_imm19(imm) check_imm(19, imm)
357 #define check_imm26(imm) check_imm(26, imm)
358
359 switch (code) {
360 /* dst = src */
361 case BPF_ALU | BPF_MOV | BPF_X:
362 case BPF_ALU64 | BPF_MOV | BPF_X:
363 emit(A64_MOV(is64, dst, src), ctx);
364 break;
365 /* dst = dst OP src */
366 case BPF_ALU | BPF_ADD | BPF_X:
367 case BPF_ALU64 | BPF_ADD | BPF_X:
368 emit(A64_ADD(is64, dst, dst, src), ctx);
369 break;
370 case BPF_ALU | BPF_SUB | BPF_X:
371 case BPF_ALU64 | BPF_SUB | BPF_X:
372 emit(A64_SUB(is64, dst, dst, src), ctx);
373 break;
374 case BPF_ALU | BPF_AND | BPF_X:
375 case BPF_ALU64 | BPF_AND | BPF_X:
376 emit(A64_AND(is64, dst, dst, src), ctx);
377 break;
378 case BPF_ALU | BPF_OR | BPF_X:
379 case BPF_ALU64 | BPF_OR | BPF_X:
380 emit(A64_ORR(is64, dst, dst, src), ctx);
381 break;
382 case BPF_ALU | BPF_XOR | BPF_X:
383 case BPF_ALU64 | BPF_XOR | BPF_X:
384 emit(A64_EOR(is64, dst, dst, src), ctx);
385 break;
386 case BPF_ALU | BPF_MUL | BPF_X:
387 case BPF_ALU64 | BPF_MUL | BPF_X:
388 emit(A64_MUL(is64, dst, dst, src), ctx);
389 break;
390 case BPF_ALU | BPF_DIV | BPF_X:
391 case BPF_ALU64 | BPF_DIV | BPF_X:
392 case BPF_ALU | BPF_MOD | BPF_X:
393 case BPF_ALU64 | BPF_MOD | BPF_X:
394 switch (BPF_OP(code)) {
395 case BPF_DIV:
396 emit(A64_UDIV(is64, dst, dst, src), ctx);
397 break;
398 case BPF_MOD:
399 emit(A64_UDIV(is64, tmp, dst, src), ctx);
400 emit(A64_MUL(is64, tmp, tmp, src), ctx);
401 emit(A64_SUB(is64, dst, dst, tmp), ctx);
402 break;
403 }
404 break;
405 case BPF_ALU | BPF_LSH | BPF_X:
406 case BPF_ALU64 | BPF_LSH | BPF_X:
407 emit(A64_LSLV(is64, dst, dst, src), ctx);
408 break;
409 case BPF_ALU | BPF_RSH | BPF_X:
410 case BPF_ALU64 | BPF_RSH | BPF_X:
411 emit(A64_LSRV(is64, dst, dst, src), ctx);
412 break;
413 case BPF_ALU | BPF_ARSH | BPF_X:
414 case BPF_ALU64 | BPF_ARSH | BPF_X:
415 emit(A64_ASRV(is64, dst, dst, src), ctx);
416 break;
417 /* dst = -dst */
418 case BPF_ALU | BPF_NEG:
419 case BPF_ALU64 | BPF_NEG:
420 emit(A64_NEG(is64, dst, dst), ctx);
421 break;
422 /* dst = BSWAP##imm(dst) */
423 case BPF_ALU | BPF_END | BPF_FROM_LE:
424 case BPF_ALU | BPF_END | BPF_FROM_BE:
425 #ifdef CONFIG_CPU_BIG_ENDIAN
426 if (BPF_SRC(code) == BPF_FROM_BE)
427 goto emit_bswap_uxt;
428 #else /* !CONFIG_CPU_BIG_ENDIAN */
429 if (BPF_SRC(code) == BPF_FROM_LE)
430 goto emit_bswap_uxt;
431 #endif
432 switch (imm) {
433 case 16:
434 emit(A64_REV16(is64, dst, dst), ctx);
435 /* zero-extend 16 bits into 64 bits */
436 emit(A64_UXTH(is64, dst, dst), ctx);
437 break;
438 case 32:
439 emit(A64_REV32(is64, dst, dst), ctx);
440 /* upper 32 bits already cleared */
441 break;
442 case 64:
443 emit(A64_REV64(dst, dst), ctx);
444 break;
445 }
446 break;
447 emit_bswap_uxt:
448 switch (imm) {
449 case 16:
450 /* zero-extend 16 bits into 64 bits */
451 emit(A64_UXTH(is64, dst, dst), ctx);
452 break;
453 case 32:
454 /* zero-extend 32 bits into 64 bits */
455 emit(A64_UXTW(is64, dst, dst), ctx);
456 break;
457 case 64:
458 /* nop */
459 break;
460 }
461 break;
462 /* dst = imm */
463 case BPF_ALU | BPF_MOV | BPF_K:
464 case BPF_ALU64 | BPF_MOV | BPF_K:
465 emit_a64_mov_i(is64, dst, imm, ctx);
466 break;
467 /* dst = dst OP imm */
468 case BPF_ALU | BPF_ADD | BPF_K:
469 case BPF_ALU64 | BPF_ADD | BPF_K:
470 emit_a64_mov_i(is64, tmp, imm, ctx);
471 emit(A64_ADD(is64, dst, dst, tmp), ctx);
472 break;
473 case BPF_ALU | BPF_SUB | BPF_K:
474 case BPF_ALU64 | BPF_SUB | BPF_K:
475 emit_a64_mov_i(is64, tmp, imm, ctx);
476 emit(A64_SUB(is64, dst, dst, tmp), ctx);
477 break;
478 case BPF_ALU | BPF_AND | BPF_K:
479 case BPF_ALU64 | BPF_AND | BPF_K:
480 emit_a64_mov_i(is64, tmp, imm, ctx);
481 emit(A64_AND(is64, dst, dst, tmp), ctx);
482 break;
483 case BPF_ALU | BPF_OR | BPF_K:
484 case BPF_ALU64 | BPF_OR | BPF_K:
485 emit_a64_mov_i(is64, tmp, imm, ctx);
486 emit(A64_ORR(is64, dst, dst, tmp), ctx);
487 break;
488 case BPF_ALU | BPF_XOR | BPF_K:
489 case BPF_ALU64 | BPF_XOR | BPF_K:
490 emit_a64_mov_i(is64, tmp, imm, ctx);
491 emit(A64_EOR(is64, dst, dst, tmp), ctx);
492 break;
493 case BPF_ALU | BPF_MUL | BPF_K:
494 case BPF_ALU64 | BPF_MUL | BPF_K:
495 emit_a64_mov_i(is64, tmp, imm, ctx);
496 emit(A64_MUL(is64, dst, dst, tmp), ctx);
497 break;
498 case BPF_ALU | BPF_DIV | BPF_K:
499 case BPF_ALU64 | BPF_DIV | BPF_K:
500 emit_a64_mov_i(is64, tmp, imm, ctx);
501 emit(A64_UDIV(is64, dst, dst, tmp), ctx);
502 break;
503 case BPF_ALU | BPF_MOD | BPF_K:
504 case BPF_ALU64 | BPF_MOD | BPF_K:
505 emit_a64_mov_i(is64, tmp2, imm, ctx);
506 emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
507 emit(A64_MUL(is64, tmp, tmp, tmp2), ctx);
508 emit(A64_SUB(is64, dst, dst, tmp), ctx);
509 break;
510 case BPF_ALU | BPF_LSH | BPF_K:
511 case BPF_ALU64 | BPF_LSH | BPF_K:
512 emit(A64_LSL(is64, dst, dst, imm), ctx);
513 break;
514 case BPF_ALU | BPF_RSH | BPF_K:
515 case BPF_ALU64 | BPF_RSH | BPF_K:
516 emit(A64_LSR(is64, dst, dst, imm), ctx);
517 break;
518 case BPF_ALU | BPF_ARSH | BPF_K:
519 case BPF_ALU64 | BPF_ARSH | BPF_K:
520 emit(A64_ASR(is64, dst, dst, imm), ctx);
521 break;
522
523 /* JUMP off */
524 case BPF_JMP | BPF_JA:
525 jmp_offset = bpf2a64_offset(i + off, i, ctx);
526 check_imm26(jmp_offset);
527 emit(A64_B(jmp_offset), ctx);
528 break;
529 /* IF (dst COND src) JUMP off */
530 case BPF_JMP | BPF_JEQ | BPF_X:
531 case BPF_JMP | BPF_JGT | BPF_X:
532 case BPF_JMP | BPF_JLT | BPF_X:
533 case BPF_JMP | BPF_JGE | BPF_X:
534 case BPF_JMP | BPF_JLE | BPF_X:
535 case BPF_JMP | BPF_JNE | BPF_X:
536 case BPF_JMP | BPF_JSGT | BPF_X:
537 case BPF_JMP | BPF_JSLT | BPF_X:
538 case BPF_JMP | BPF_JSGE | BPF_X:
539 case BPF_JMP | BPF_JSLE | BPF_X:
540 emit(A64_CMP(1, dst, src), ctx);
541 emit_cond_jmp:
542 jmp_offset = bpf2a64_offset(i + off, i, ctx);
543 check_imm19(jmp_offset);
544 switch (BPF_OP(code)) {
545 case BPF_JEQ:
546 jmp_cond = A64_COND_EQ;
547 break;
548 case BPF_JGT:
549 jmp_cond = A64_COND_HI;
550 break;
551 case BPF_JLT:
552 jmp_cond = A64_COND_CC;
553 break;
554 case BPF_JGE:
555 jmp_cond = A64_COND_CS;
556 break;
557 case BPF_JLE:
558 jmp_cond = A64_COND_LS;
559 break;
560 case BPF_JSET:
561 case BPF_JNE:
562 jmp_cond = A64_COND_NE;
563 break;
564 case BPF_JSGT:
565 jmp_cond = A64_COND_GT;
566 break;
567 case BPF_JSLT:
568 jmp_cond = A64_COND_LT;
569 break;
570 case BPF_JSGE:
571 jmp_cond = A64_COND_GE;
572 break;
573 case BPF_JSLE:
574 jmp_cond = A64_COND_LE;
575 break;
576 default:
577 return -EFAULT;
578 }
579 emit(A64_B_(jmp_cond, jmp_offset), ctx);
580 break;
581 case BPF_JMP | BPF_JSET | BPF_X:
582 emit(A64_TST(1, dst, src), ctx);
583 goto emit_cond_jmp;
584 /* IF (dst COND imm) JUMP off */
585 case BPF_JMP | BPF_JEQ | BPF_K:
586 case BPF_JMP | BPF_JGT | BPF_K:
587 case BPF_JMP | BPF_JLT | BPF_K:
588 case BPF_JMP | BPF_JGE | BPF_K:
589 case BPF_JMP | BPF_JLE | BPF_K:
590 case BPF_JMP | BPF_JNE | BPF_K:
591 case BPF_JMP | BPF_JSGT | BPF_K:
592 case BPF_JMP | BPF_JSLT | BPF_K:
593 case BPF_JMP | BPF_JSGE | BPF_K:
594 case BPF_JMP | BPF_JSLE | BPF_K:
595 emit_a64_mov_i(1, tmp, imm, ctx);
596 emit(A64_CMP(1, dst, tmp), ctx);
597 goto emit_cond_jmp;
598 case BPF_JMP | BPF_JSET | BPF_K:
599 emit_a64_mov_i(1, tmp, imm, ctx);
600 emit(A64_TST(1, dst, tmp), ctx);
601 goto emit_cond_jmp;
602 /* function call */
603 case BPF_JMP | BPF_CALL:
604 {
605 const u8 r0 = bpf2a64[BPF_REG_0];
606 const u64 func = (u64)__bpf_call_base + imm;
607
608 if (ctx->prog->is_func)
609 emit_addr_mov_i64(tmp, func, ctx);
610 else
611 emit_a64_mov_i64(tmp, func, ctx);
612 emit(A64_BLR(tmp), ctx);
613 emit(A64_MOV(1, r0, A64_R(0)), ctx);
614 break;
615 }
616 /* tail call */
617 case BPF_JMP | BPF_TAIL_CALL:
618 if (emit_bpf_tail_call(ctx))
619 return -EFAULT;
620 break;
621 /* function return */
622 case BPF_JMP | BPF_EXIT:
623 /* Optimization: when last instruction is EXIT,
624 simply fallthrough to epilogue. */
625 if (i == ctx->prog->len - 1)
626 break;
627 jmp_offset = epilogue_offset(ctx);
628 check_imm26(jmp_offset);
629 emit(A64_B(jmp_offset), ctx);
630 break;
631
632 /* dst = imm64 */
633 case BPF_LD | BPF_IMM | BPF_DW:
634 {
635 const struct bpf_insn insn1 = insn[1];
636 u64 imm64;
637
638 imm64 = (u64)insn1.imm << 32 | (u32)imm;
639 emit_a64_mov_i64(dst, imm64, ctx);
640
641 return 1;
642 }
643
644 /* LDX: dst = *(size *)(src + off) */
645 case BPF_LDX | BPF_MEM | BPF_W:
646 case BPF_LDX | BPF_MEM | BPF_H:
647 case BPF_LDX | BPF_MEM | BPF_B:
648 case BPF_LDX | BPF_MEM | BPF_DW:
649 emit_a64_mov_i(1, tmp, off, ctx);
650 switch (BPF_SIZE(code)) {
651 case BPF_W:
652 emit(A64_LDR32(dst, src, tmp), ctx);
653 break;
654 case BPF_H:
655 emit(A64_LDRH(dst, src, tmp), ctx);
656 break;
657 case BPF_B:
658 emit(A64_LDRB(dst, src, tmp), ctx);
659 break;
660 case BPF_DW:
661 emit(A64_LDR64(dst, src, tmp), ctx);
662 break;
663 }
664 break;
665
666 /* ST: *(size *)(dst + off) = imm */
667 case BPF_ST | BPF_MEM | BPF_W:
668 case BPF_ST | BPF_MEM | BPF_H:
669 case BPF_ST | BPF_MEM | BPF_B:
670 case BPF_ST | BPF_MEM | BPF_DW:
671 /* Load imm to a register then store it */
672 emit_a64_mov_i(1, tmp2, off, ctx);
673 emit_a64_mov_i(1, tmp, imm, ctx);
674 switch (BPF_SIZE(code)) {
675 case BPF_W:
676 emit(A64_STR32(tmp, dst, tmp2), ctx);
677 break;
678 case BPF_H:
679 emit(A64_STRH(tmp, dst, tmp2), ctx);
680 break;
681 case BPF_B:
682 emit(A64_STRB(tmp, dst, tmp2), ctx);
683 break;
684 case BPF_DW:
685 emit(A64_STR64(tmp, dst, tmp2), ctx);
686 break;
687 }
688 break;
689
690 /* STX: *(size *)(dst + off) = src */
691 case BPF_STX | BPF_MEM | BPF_W:
692 case BPF_STX | BPF_MEM | BPF_H:
693 case BPF_STX | BPF_MEM | BPF_B:
694 case BPF_STX | BPF_MEM | BPF_DW:
695 emit_a64_mov_i(1, tmp, off, ctx);
696 switch (BPF_SIZE(code)) {
697 case BPF_W:
698 emit(A64_STR32(src, dst, tmp), ctx);
699 break;
700 case BPF_H:
701 emit(A64_STRH(src, dst, tmp), ctx);
702 break;
703 case BPF_B:
704 emit(A64_STRB(src, dst, tmp), ctx);
705 break;
706 case BPF_DW:
707 emit(A64_STR64(src, dst, tmp), ctx);
708 break;
709 }
710 break;
711 /* STX XADD: lock *(u32 *)(dst + off) += src */
712 case BPF_STX | BPF_XADD | BPF_W:
713 /* STX XADD: lock *(u64 *)(dst + off) += src */
714 case BPF_STX | BPF_XADD | BPF_DW:
715 emit_a64_mov_i(1, tmp, off, ctx);
716 emit(A64_ADD(1, tmp, tmp, dst), ctx);
717 emit(A64_PRFM(tmp, PST, L1, STRM), ctx);
718 emit(A64_LDXR(isdw, tmp2, tmp), ctx);
719 emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
720 emit(A64_STXR(isdw, tmp2, tmp, tmp3), ctx);
721 jmp_offset = -3;
722 check_imm19(jmp_offset);
723 emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
724 break;
725
726 /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */
727 case BPF_LD | BPF_ABS | BPF_W:
728 case BPF_LD | BPF_ABS | BPF_H:
729 case BPF_LD | BPF_ABS | BPF_B:
730 /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */
731 case BPF_LD | BPF_IND | BPF_W:
732 case BPF_LD | BPF_IND | BPF_H:
733 case BPF_LD | BPF_IND | BPF_B:
734 {
735 const u8 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */
736 const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */
737 const u8 fp = bpf2a64[BPF_REG_FP];
738 const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */
739 const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */
740 const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */
741 const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */
742 const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */
743 int size;
744
745 emit(A64_MOV(1, r1, r6), ctx);
746 emit_a64_mov_i(0, r2, imm, ctx);
747 if (BPF_MODE(code) == BPF_IND)
748 emit(A64_ADD(0, r2, r2, src), ctx);
749 switch (BPF_SIZE(code)) {
750 case BPF_W:
751 size = 4;
752 break;
753 case BPF_H:
754 size = 2;
755 break;
756 case BPF_B:
757 size = 1;
758 break;
759 default:
760 return -EINVAL;
761 }
762 emit_a64_mov_i64(r3, size, ctx);
763 emit(A64_SUB_I(1, r4, fp, ctx->stack_size), ctx);
764 emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
765 emit(A64_BLR(r5), ctx);
766 emit(A64_MOV(1, r0, A64_R(0)), ctx);
767
768 jmp_offset = epilogue_offset(ctx);
769 check_imm19(jmp_offset);
770 emit(A64_CBZ(1, r0, jmp_offset), ctx);
771 emit(A64_MOV(1, r5, r0), ctx);
772 switch (BPF_SIZE(code)) {
773 case BPF_W:
774 emit(A64_LDR32(r0, r5, A64_ZR), ctx);
775 #ifndef CONFIG_CPU_BIG_ENDIAN
776 emit(A64_REV32(0, r0, r0), ctx);
777 #endif
778 break;
779 case BPF_H:
780 emit(A64_LDRH(r0, r5, A64_ZR), ctx);
781 #ifndef CONFIG_CPU_BIG_ENDIAN
782 emit(A64_REV16(0, r0, r0), ctx);
783 #endif
784 break;
785 case BPF_B:
786 emit(A64_LDRB(r0, r5, A64_ZR), ctx);
787 break;
788 }
789 break;
790 }
791 default:
792 pr_err_once("unknown opcode %02x\n", code);
793 return -EINVAL;
794 }
795
796 return 0;
797 }
798
799 static int build_body(struct jit_ctx *ctx)
800 {
801 const struct bpf_prog *prog = ctx->prog;
802 int i;
803
804 for (i = 0; i < prog->len; i++) {
805 const struct bpf_insn *insn = &prog->insnsi[i];
806 int ret;
807
808 ret = build_insn(insn, ctx);
809 if (ret > 0) {
810 i++;
811 if (ctx->image == NULL)
812 ctx->offset[i] = ctx->idx;
813 continue;
814 }
815 if (ctx->image == NULL)
816 ctx->offset[i] = ctx->idx;
817 if (ret)
818 return ret;
819 }
820
821 return 0;
822 }
823
824 static int validate_code(struct jit_ctx *ctx)
825 {
826 int i;
827
828 for (i = 0; i < ctx->idx; i++) {
829 u32 a64_insn = le32_to_cpu(ctx->image[i]);
830
831 if (a64_insn == AARCH64_BREAK_FAULT)
832 return -1;
833 }
834
835 return 0;
836 }
837
838 static inline void bpf_flush_icache(void *start, void *end)
839 {
840 flush_icache_range((unsigned long)start, (unsigned long)end);
841 }
842
843 struct arm64_jit_data {
844 struct bpf_binary_header *header;
845 u8 *image;
846 struct jit_ctx ctx;
847 };
848
849 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
850 {
851 struct bpf_prog *tmp, *orig_prog = prog;
852 struct bpf_binary_header *header;
853 struct arm64_jit_data *jit_data;
854 bool tmp_blinded = false;
855 bool extra_pass = false;
856 struct jit_ctx ctx;
857 int image_size;
858 u8 *image_ptr;
859
860 if (!prog->jit_requested)
861 return orig_prog;
862
863 tmp = bpf_jit_blind_constants(prog);
864 /* If blinding was requested and we failed during blinding,
865 * we must fall back to the interpreter.
866 */
867 if (IS_ERR(tmp))
868 return orig_prog;
869 if (tmp != prog) {
870 tmp_blinded = true;
871 prog = tmp;
872 }
873
874 jit_data = prog->aux->jit_data;
875 if (!jit_data) {
876 jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
877 if (!jit_data) {
878 prog = orig_prog;
879 goto out;
880 }
881 prog->aux->jit_data = jit_data;
882 }
883 if (jit_data->ctx.offset) {
884 ctx = jit_data->ctx;
885 image_ptr = jit_data->image;
886 header = jit_data->header;
887 extra_pass = true;
888 image_size = sizeof(u32) * ctx.idx;
889 goto skip_init_ctx;
890 }
891 memset(&ctx, 0, sizeof(ctx));
892 ctx.prog = prog;
893
894 ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
895 if (ctx.offset == NULL) {
896 prog = orig_prog;
897 goto out_off;
898 }
899
900 /* 1. Initial fake pass to compute ctx->idx. */
901
902 /* Fake pass to fill in ctx->offset. */
903 if (build_body(&ctx)) {
904 prog = orig_prog;
905 goto out_off;
906 }
907
908 if (build_prologue(&ctx)) {
909 prog = orig_prog;
910 goto out_off;
911 }
912
913 ctx.epilogue_offset = ctx.idx;
914 build_epilogue(&ctx);
915
916 /* Now we know the actual image size. */
917 image_size = sizeof(u32) * ctx.idx;
918 header = bpf_jit_binary_alloc(image_size, &image_ptr,
919 sizeof(u32), jit_fill_hole);
920 if (header == NULL) {
921 prog = orig_prog;
922 goto out_off;
923 }
924
925 /* 2. Now, the actual pass. */
926
927 ctx.image = (__le32 *)image_ptr;
928 skip_init_ctx:
929 ctx.idx = 0;
930
931 build_prologue(&ctx);
932
933 if (build_body(&ctx)) {
934 bpf_jit_binary_free(header);
935 prog = orig_prog;
936 goto out_off;
937 }
938
939 build_epilogue(&ctx);
940
941 /* 3. Extra pass to validate JITed code. */
942 if (validate_code(&ctx)) {
943 bpf_jit_binary_free(header);
944 prog = orig_prog;
945 goto out_off;
946 }
947
948 /* And we're done. */
949 if (bpf_jit_enable > 1)
950 bpf_jit_dump(prog->len, image_size, 2, ctx.image);
951
952 bpf_flush_icache(header, ctx.image + ctx.idx);
953
954 if (!prog->is_func || extra_pass) {
955 if (extra_pass && ctx.idx != jit_data->ctx.idx) {
956 pr_err_once("multi-func JIT bug %d != %d\n",
957 ctx.idx, jit_data->ctx.idx);
958 bpf_jit_binary_free(header);
959 prog->bpf_func = NULL;
960 prog->jited = 0;
961 goto out_off;
962 }
963 bpf_jit_binary_lock_ro(header);
964 } else {
965 jit_data->ctx = ctx;
966 jit_data->image = image_ptr;
967 jit_data->header = header;
968 }
969 prog->bpf_func = (void *)ctx.image;
970 prog->jited = 1;
971 prog->jited_len = image_size;
972
973 if (!prog->is_func || extra_pass) {
974 out_off:
975 kfree(ctx.offset);
976 kfree(jit_data);
977 prog->aux->jit_data = NULL;
978 }
979 out:
980 if (tmp_blinded)
981 bpf_jit_prog_release_other(prog, prog == orig_prog ?
982 tmp : orig_prog);
983 return prog;
984 }
CRIS linux kernel tree