1/*
2 * bpf_jit_comp.c: BPF JIT compiler
3 *
4 * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
5 * Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; version 2
10 * of the License.
11 */
12#include <linux/netdevice.h>
13#include <linux/filter.h>
14#include <linux/if_vlan.h>
15#include <linux/bpf.h>
16
17#include <asm/set_memory.h>
18#include <asm/nospec-branch.h>
19
20static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
21{
22 if (len == 1)
23 *ptr = bytes;
24 else if (len == 2)
25 *(u16 *)ptr = bytes;
26 else {
27 *(u32 *)ptr = bytes;
28 barrier();
29 }
30 return ptr + len;
31}
32
33#define EMIT(bytes, len) \
34 do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
35
36#define EMIT1(b1) EMIT(b1, 1)
37#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
38#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
39#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
40
41#define EMIT1_off32(b1, off) \
42 do { EMIT1(b1); EMIT(off, 4); } while (0)
43#define EMIT2_off32(b1, b2, off) \
44 do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
45#define EMIT3_off32(b1, b2, b3, off) \
46 do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
47#define EMIT4_off32(b1, b2, b3, b4, off) \
48 do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
49
50static bool is_imm8(int value)
51{
52 return value <= 127 && value >= -128;
53}
54
55static bool is_simm32(s64 value)
56{
57 return value == (s64)(s32)value;
58}
59
60static bool is_uimm32(u64 value)
61{
62 return value == (u64)(u32)value;
63}
64
65/* mov dst, src */
66#define EMIT_mov(DST, SRC) \
67 do { \
68 if (DST != SRC) \
69 EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
70 } while (0)
71
72static int bpf_size_to_x86_bytes(int bpf_size)
73{
74 if (bpf_size == BPF_W)
75 return 4;
76 else if (bpf_size == BPF_H)
77 return 2;
78 else if (bpf_size == BPF_B)
79 return 1;
80 else if (bpf_size == BPF_DW)
81 return 4; /* imm32 */
82 else
83 return 0;
84}
85
86/*
87 * List of x86 cond jumps opcodes (. + s8)
88 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
89 */
90#define X86_JB 0x72
91#define X86_JAE 0x73
92#define X86_JE 0x74
93#define X86_JNE 0x75
94#define X86_JBE 0x76
95#define X86_JA 0x77
96#define X86_JL 0x7C
97#define X86_JGE 0x7D
98#define X86_JLE 0x7E
99#define X86_JG 0x7F
100
101/* Pick a register outside of BPF range for JIT internal work */
102#define AUX_REG (MAX_BPF_JIT_REG + 1)
103
104/*
105 * The following table maps BPF registers to x86-64 registers.
106 *
107 * x86-64 register R12 is unused, since if used as base address
108 * register in load/store instructions, it always needs an
109 * extra byte of encoding and is callee saved.
110 *
111 * Also x86-64 register R9 is unused. x86-64 register R10 is
112 * used for blinding (if enabled).
113 */
114static const int reg2hex[] = {
115 [BPF_REG_0] = 0, /* RAX */
116 [BPF_REG_1] = 7, /* RDI */
117 [BPF_REG_2] = 6, /* RSI */
118 [BPF_REG_3] = 2, /* RDX */
119 [BPF_REG_4] = 1, /* RCX */
120 [BPF_REG_5] = 0, /* R8 */
121 [BPF_REG_6] = 3, /* RBX callee saved */
122 [BPF_REG_7] = 5, /* R13 callee saved */
123 [BPF_REG_8] = 6, /* R14 callee saved */
124 [BPF_REG_9] = 7, /* R15 callee saved */
125 [BPF_REG_FP] = 5, /* RBP readonly */
126 [BPF_REG_AX] = 2, /* R10 temp register */
127 [AUX_REG] = 3, /* R11 temp register */
128};
129
130/*
131 * is_ereg() == true if BPF register 'reg' maps to x86-64 r8..r15
132 * which need extra byte of encoding.
133 * rax,rcx,...,rbp have simpler encoding
134 */
135static bool is_ereg(u32 reg)
136{
137 return (1 << reg) & (BIT(BPF_REG_5) |
138 BIT(AUX_REG) |
139 BIT(BPF_REG_7) |
140 BIT(BPF_REG_8) |
141 BIT(BPF_REG_9) |
142 BIT(BPF_REG_AX));
143}
144
145static bool is_axreg(u32 reg)
146{
147 return reg == BPF_REG_0;
148}
149
150/* Add modifiers if 'reg' maps to x86-64 registers R8..R15 */
151static u8 add_1mod(u8 byte, u32 reg)
152{
153 if (is_ereg(reg))
154 byte |= 1;
155 return byte;
156}
157
158static u8 add_2mod(u8 byte, u32 r1, u32 r2)
159{
160 if (is_ereg(r1))
161 byte |= 1;
162 if (is_ereg(r2))
163 byte |= 4;
164 return byte;
165}
166
167/* Encode 'dst_reg' register into x86-64 opcode 'byte' */
168static u8 add_1reg(u8 byte, u32 dst_reg)
169{
170 return byte + reg2hex[dst_reg];
171}
172
173/* Encode 'dst_reg' and 'src_reg' registers into x86-64 opcode 'byte' */
174static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
175{
176 return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
177}
178
179static void jit_fill_hole(void *area, unsigned int size)
180{
181 /* Fill whole space with INT3 instructions */
182 memset(area, 0xcc, size);
183}
184
185struct jit_context {
186 int cleanup_addr; /* Epilogue code offset */
187};
188
189/* Maximum number of bytes emitted while JITing one eBPF insn */
190#define BPF_MAX_INSN_SIZE 128
191#define BPF_INSN_SAFETY 64
192
193#define AUX_STACK_SPACE 40 /* Space for RBX, R13, R14, R15, tailcnt */
194
195#define PROLOGUE_SIZE 37
196
197/*
198 * Emit x86-64 prologue code for BPF program and check its size.
199 * bpf_tail_call helper will skip it while jumping into another program
200 */
201static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf)
202{
203 u8 *prog = *pprog;
204 int cnt = 0;
205
206 /* push rbp */
207 EMIT1(0x55);
208
209 /* mov rbp,rsp */
210 EMIT3(0x48, 0x89, 0xE5);
211
212 /* sub rsp, rounded_stack_depth + AUX_STACK_SPACE */
213 EMIT3_off32(0x48, 0x81, 0xEC,
214 round_up(stack_depth, 8) + AUX_STACK_SPACE);
215
216 /* sub rbp, AUX_STACK_SPACE */
217 EMIT4(0x48, 0x83, 0xED, AUX_STACK_SPACE);
218
219 /* mov qword ptr [rbp+0],rbx */
220 EMIT4(0x48, 0x89, 0x5D, 0);
221 /* mov qword ptr [rbp+8],r13 */
222 EMIT4(0x4C, 0x89, 0x6D, 8);
223 /* mov qword ptr [rbp+16],r14 */
224 EMIT4(0x4C, 0x89, 0x75, 16);
225 /* mov qword ptr [rbp+24],r15 */
226 EMIT4(0x4C, 0x89, 0x7D, 24);
227
228 if (!ebpf_from_cbpf) {
229 /*
230 * Clear the tail call counter (tail_call_cnt): for eBPF tail
231 * calls we need to reset the counter to 0. It's done in two
232 * instructions, resetting RAX register to 0, and moving it
233 * to the counter location.
234 */
235
236 /* xor eax, eax */
237 EMIT2(0x31, 0xc0);
238 /* mov qword ptr [rbp+32], rax */
239 EMIT4(0x48, 0x89, 0x45, 32);
240
241 BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
242 }
243
244 *pprog = prog;
245}
246
247/*
248 * Generate the following code:
249 *
250 * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
251 * if (index >= array->map.max_entries)
252 * goto out;
253 * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
254 * goto out;
255 * prog = array->ptrs[index];
256 * if (prog == NULL)
257 * goto out;
258 * goto *(prog->bpf_func + prologue_size);
259 * out:
260 */
261static void emit_bpf_tail_call(u8 **pprog)
262{
263 u8 *prog = *pprog;
264 int label1, label2, label3;
265 int cnt = 0;
266
267 /*
268 * rdi - pointer to ctx
269 * rsi - pointer to bpf_array
270 * rdx - index in bpf_array
271 */
272
273 /*
274 * if (index >= array->map.max_entries)
275 * goto out;
276 */
277 EMIT2(0x89, 0xD2); /* mov edx, edx */
278 EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
279 offsetof(struct bpf_array, map.max_entries));
280#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* Number of bytes to jump */
281 EMIT2(X86_JBE, OFFSET1); /* jbe out */
282 label1 = cnt;
283
284 /*
285 * if (tail_call_cnt > MAX_TAIL_CALL_CNT)
286 * goto out;
287 */
288 EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */
289 EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
290#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
291 EMIT2(X86_JA, OFFSET2); /* ja out */
292 label2 = cnt;
293 EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
294 EMIT2_off32(0x89, 0x85, 36); /* mov dword ptr [rbp + 36], eax */
295
296 /* prog = array->ptrs[index]; */
297 EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */
298 offsetof(struct bpf_array, ptrs));
299
300 /*
301 * if (prog == NULL)
302 * goto out;
303 */
304 EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
305#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
306 EMIT2(X86_JE, OFFSET3); /* je out */
307 label3 = cnt;
308
309 /* goto *(prog->bpf_func + prologue_size); */
310 EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
311 offsetof(struct bpf_prog, bpf_func));
312 EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
313
314 /*
315 * Wow we're ready to jump into next BPF program
316 * rdi == ctx (1st arg)
317 * rax == prog->bpf_func + prologue_size
318 */
319 RETPOLINE_RAX_BPF_JIT();
320
321 /* out: */
322 BUILD_BUG_ON(cnt - label1 != OFFSET1);
323 BUILD_BUG_ON(cnt - label2 != OFFSET2);
324 BUILD_BUG_ON(cnt - label3 != OFFSET3);
325 *pprog = prog;
326}
327
328static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
329 u32 dst_reg, const u32 imm32)
330{
331 u8 *prog = *pprog;
332 u8 b1, b2, b3;
333 int cnt = 0;
334
335 /*
336 * Optimization: if imm32 is positive, use 'mov %eax, imm32'
337 * (which zero-extends imm32) to save 2 bytes.
338 */
339 if (sign_propagate && (s32)imm32 < 0) {
340 /* 'mov %rax, imm32' sign extends imm32 */
341 b1 = add_1mod(0x48, dst_reg);
342 b2 = 0xC7;
343 b3 = 0xC0;
344 EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32);
345 goto done;
346 }
347
348 /*
349 * Optimization: if imm32 is zero, use 'xor %eax, %eax'
350 * to save 3 bytes.
351 */
352 if (imm32 == 0) {
353 if (is_ereg(dst_reg))
354 EMIT1(add_2mod(0x40, dst_reg, dst_reg));
355 b2 = 0x31; /* xor */
356 b3 = 0xC0;
357 EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
358 goto done;
359 }
360
361 /* mov %eax, imm32 */
362 if (is_ereg(dst_reg))
363 EMIT1(add_1mod(0x40, dst_reg));
364 EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
365done:
366 *pprog = prog;
367}
368
369static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
370 const u32 imm32_hi, const u32 imm32_lo)
371{
372 u8 *prog = *pprog;
373 int cnt = 0;
374
375 if (is_uimm32(((u64)imm32_hi << 32) | (u32)imm32_lo)) {
376 /*
377 * For emitting plain u32, where sign bit must not be
378 * propagated LLVM tends to load imm64 over mov32
379 * directly, so save couple of bytes by just doing
380 * 'mov %eax, imm32' instead.
381 */
382 emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
383 } else {
384 /* movabsq %rax, imm64 */
385 EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
386 EMIT(imm32_lo, 4);
387 EMIT(imm32_hi, 4);
388 }
389
390 *pprog = prog;
391}
392
393static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg)
394{
395 u8 *prog = *pprog;
396 int cnt = 0;
397
398 if (is64) {
399 /* mov dst, src */
400 EMIT_mov(dst_reg, src_reg);
401 } else {
402 /* mov32 dst, src */
403 if (is_ereg(dst_reg) || is_ereg(src_reg))
404 EMIT1(add_2mod(0x40, dst_reg, src_reg));
405 EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
406 }
407
408 *pprog = prog;
409}
410
411static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
412 int oldproglen, struct jit_context *ctx)
413{
414 struct bpf_insn *insn = bpf_prog->insnsi;
415 int insn_cnt = bpf_prog->len;
416 bool seen_exit = false;
417 u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
418 int i, cnt = 0;
419 int proglen = 0;
420 u8 *prog = temp;
421
422 emit_prologue(&prog, bpf_prog->aux->stack_depth,
423 bpf_prog_was_classic(bpf_prog));
424
425 for (i = 0; i < insn_cnt; i++, insn++) {
426 const s32 imm32 = insn->imm;
427 u32 dst_reg = insn->dst_reg;
428 u32 src_reg = insn->src_reg;
429 u8 b2 = 0, b3 = 0;
430 s64 jmp_offset;
431 u8 jmp_cond;
432 int ilen;
433 u8 *func;
434
435 switch (insn->code) {
436 /* ALU */
437 case BPF_ALU | BPF_ADD | BPF_X:
438 case BPF_ALU | BPF_SUB | BPF_X:
439 case BPF_ALU | BPF_AND | BPF_X:
440 case BPF_ALU | BPF_OR | BPF_X:
441 case BPF_ALU | BPF_XOR | BPF_X:
442 case BPF_ALU64 | BPF_ADD | BPF_X:
443 case BPF_ALU64 | BPF_SUB | BPF_X:
444 case BPF_ALU64 | BPF_AND | BPF_X:
445 case BPF_ALU64 | BPF_OR | BPF_X:
446 case BPF_ALU64 | BPF_XOR | BPF_X:
447 switch (BPF_OP(insn->code)) {
448 case BPF_ADD: b2 = 0x01; break;
449 case BPF_SUB: b2 = 0x29; break;
450 case BPF_AND: b2 = 0x21; break;
451 case BPF_OR: b2 = 0x09; break;
452 case BPF_XOR: b2 = 0x31; break;
453 }
454 if (BPF_CLASS(insn->code) == BPF_ALU64)
455 EMIT1(add_2mod(0x48, dst_reg, src_reg));
456 else if (is_ereg(dst_reg) || is_ereg(src_reg))
457 EMIT1(add_2mod(0x40, dst_reg, src_reg));
458 EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
459 break;
460
461 case BPF_ALU64 | BPF_MOV | BPF_X:
462 case BPF_ALU | BPF_MOV | BPF_X:
463 emit_mov_reg(&prog,
464 BPF_CLASS(insn->code) == BPF_ALU64,
465 dst_reg, src_reg);
466 break;
467
468 /* neg dst */
469 case BPF_ALU | BPF_NEG:
470 case BPF_ALU64 | BPF_NEG:
471 if (BPF_CLASS(insn->code) == BPF_ALU64)
472 EMIT1(add_1mod(0x48, dst_reg));
473 else if (is_ereg(dst_reg))
474 EMIT1(add_1mod(0x40, dst_reg));
475 EMIT2(0xF7, add_1reg(0xD8, dst_reg));
476 break;
477
478 case BPF_ALU | BPF_ADD | BPF_K:
479 case BPF_ALU | BPF_SUB | BPF_K:
480 case BPF_ALU | BPF_AND | BPF_K:
481 case BPF_ALU | BPF_OR | BPF_K:
482 case BPF_ALU | BPF_XOR | BPF_K:
483 case BPF_ALU64 | BPF_ADD | BPF_K:
484 case BPF_ALU64 | BPF_SUB | BPF_K:
485 case BPF_ALU64 | BPF_AND | BPF_K:
486 case BPF_ALU64 | BPF_OR | BPF_K:
487 case BPF_ALU64 | BPF_XOR | BPF_K:
488 if (BPF_CLASS(insn->code) == BPF_ALU64)
489 EMIT1(add_1mod(0x48, dst_reg));
490 else if (is_ereg(dst_reg))
491 EMIT1(add_1mod(0x40, dst_reg));
492
493 /*
494 * b3 holds 'normal' opcode, b2 short form only valid
495 * in case dst is eax/rax.
496 */
497 switch (BPF_OP(insn->code)) {
498 case BPF_ADD:
499 b3 = 0xC0;
500 b2 = 0x05;
501 break;
502 case BPF_SUB:
503 b3 = 0xE8;
504 b2 = 0x2D;
505 break;
506 case BPF_AND:
507 b3 = 0xE0;
508 b2 = 0x25;
509 break;
510 case BPF_OR:
511 b3 = 0xC8;
512 b2 = 0x0D;
513 break;
514 case BPF_XOR:
515 b3 = 0xF0;
516 b2 = 0x35;
517 break;
518 }
519
520 if (is_imm8(imm32))
521 EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
522 else if (is_axreg(dst_reg))
523 EMIT1_off32(b2, imm32);
524 else
525 EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
526 break;
527
528 case BPF_ALU64 | BPF_MOV | BPF_K:
529 case BPF_ALU | BPF_MOV | BPF_K:
530 emit_mov_imm32(&prog, BPF_CLASS(insn->code) == BPF_ALU64,
531 dst_reg, imm32);
532 break;
533
534 case BPF_LD | BPF_IMM | BPF_DW:
535 emit_mov_imm64(&prog, dst_reg, insn[1].imm, insn[0].imm);
536 insn++;
537 i++;
538 break;
539
540 /* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
541 case BPF_ALU | BPF_MOD | BPF_X:
542 case BPF_ALU | BPF_DIV | BPF_X:
543 case BPF_ALU | BPF_MOD | BPF_K:
544 case BPF_ALU | BPF_DIV | BPF_K:
545 case BPF_ALU64 | BPF_MOD | BPF_X:
546 case BPF_ALU64 | BPF_DIV | BPF_X:
547 case BPF_ALU64 | BPF_MOD | BPF_K:
548 case BPF_ALU64 | BPF_DIV | BPF_K:
549 EMIT1(0x50); /* push rax */
550 EMIT1(0x52); /* push rdx */
551
552 if (BPF_SRC(insn->code) == BPF_X)
553 /* mov r11, src_reg */
554 EMIT_mov(AUX_REG, src_reg);
555 else
556 /* mov r11, imm32 */
557 EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
558
559 /* mov rax, dst_reg */
560 EMIT_mov(BPF_REG_0, dst_reg);
561
562 /*
563 * xor edx, edx
564 * equivalent to 'xor rdx, rdx', but one byte less
565 */
566 EMIT2(0x31, 0xd2);
567
568 if (BPF_CLASS(insn->code) == BPF_ALU64)
569 /* div r11 */
570 EMIT3(0x49, 0xF7, 0xF3);
571 else
572 /* div r11d */
573 EMIT3(0x41, 0xF7, 0xF3);
574
575 if (BPF_OP(insn->code) == BPF_MOD)
576 /* mov r11, rdx */
577 EMIT3(0x49, 0x89, 0xD3);
578 else
579 /* mov r11, rax */
580 EMIT3(0x49, 0x89, 0xC3);
581
582 EMIT1(0x5A); /* pop rdx */
583 EMIT1(0x58); /* pop rax */
584
585 /* mov dst_reg, r11 */
586 EMIT_mov(dst_reg, AUX_REG);
587 break;
588
589 case BPF_ALU | BPF_MUL | BPF_K:
590 case BPF_ALU | BPF_MUL | BPF_X:
591 case BPF_ALU64 | BPF_MUL | BPF_K:
592 case BPF_ALU64 | BPF_MUL | BPF_X:
593 {
594 bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
595
596 if (dst_reg != BPF_REG_0)
597 EMIT1(0x50); /* push rax */
598 if (dst_reg != BPF_REG_3)
599 EMIT1(0x52); /* push rdx */
600
601 /* mov r11, dst_reg */
602 EMIT_mov(AUX_REG, dst_reg);
603
604 if (BPF_SRC(insn->code) == BPF_X)
605 emit_mov_reg(&prog, is64, BPF_REG_0, src_reg);
606 else
607 emit_mov_imm32(&prog, is64, BPF_REG_0, imm32);
608
609 if (is64)
610 EMIT1(add_1mod(0x48, AUX_REG));
611 else if (is_ereg(AUX_REG))
612 EMIT1(add_1mod(0x40, AUX_REG));
613 /* mul(q) r11 */
614 EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
615
616 if (dst_reg != BPF_REG_3)
617 EMIT1(0x5A); /* pop rdx */
618 if (dst_reg != BPF_REG_0) {
619 /* mov dst_reg, rax */
620 EMIT_mov(dst_reg, BPF_REG_0);
621 EMIT1(0x58); /* pop rax */
622 }
623 break;
624 }
625 /* Shifts */
626 case BPF_ALU | BPF_LSH | BPF_K:
627 case BPF_ALU | BPF_RSH | BPF_K:
628 case BPF_ALU | BPF_ARSH | BPF_K:
629 case BPF_ALU64 | BPF_LSH | BPF_K:
630 case BPF_ALU64 | BPF_RSH | BPF_K:
631 case BPF_ALU64 | BPF_ARSH | BPF_K:
632 if (BPF_CLASS(insn->code) == BPF_ALU64)
633 EMIT1(add_1mod(0x48, dst_reg));
634 else if (is_ereg(dst_reg))
635 EMIT1(add_1mod(0x40, dst_reg));
636
637 switch (BPF_OP(insn->code)) {
638 case BPF_LSH: b3 = 0xE0; break;
639 case BPF_RSH: b3 = 0xE8; break;
640 case BPF_ARSH: b3 = 0xF8; break;
641 }
642
643 if (imm32 == 1)
644 EMIT2(0xD1, add_1reg(b3, dst_reg));
645 else
646 EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
647 break;
648
649 case BPF_ALU | BPF_LSH | BPF_X:
650 case BPF_ALU | BPF_RSH | BPF_X:
651 case BPF_ALU | BPF_ARSH | BPF_X:
652 case BPF_ALU64 | BPF_LSH | BPF_X:
653 case BPF_ALU64 | BPF_RSH | BPF_X:
654 case BPF_ALU64 | BPF_ARSH | BPF_X:
655
656 /* Check for bad case when dst_reg == rcx */
657 if (dst_reg == BPF_REG_4) {
658 /* mov r11, dst_reg */
659 EMIT_mov(AUX_REG, dst_reg);
660 dst_reg = AUX_REG;
661 }
662
663 if (src_reg != BPF_REG_4) { /* common case */
664 EMIT1(0x51); /* push rcx */
665
666 /* mov rcx, src_reg */
667 EMIT_mov(BPF_REG_4, src_reg);
668 }
669
670 /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
671 if (BPF_CLASS(insn->code) == BPF_ALU64)
672 EMIT1(add_1mod(0x48, dst_reg));
673 else if (is_ereg(dst_reg))
674 EMIT1(add_1mod(0x40, dst_reg));
675
676 switch (BPF_OP(insn->code)) {
677 case BPF_LSH: b3 = 0xE0; break;
678 case BPF_RSH: b3 = 0xE8; break;
679 case BPF_ARSH: b3 = 0xF8; break;
680 }
681 EMIT2(0xD3, add_1reg(b3, dst_reg));
682
683 if (src_reg != BPF_REG_4)
684 EMIT1(0x59); /* pop rcx */
685
686 if (insn->dst_reg == BPF_REG_4)
687 /* mov dst_reg, r11 */
688 EMIT_mov(insn->dst_reg, AUX_REG);
689 break;
690
691 case BPF_ALU | BPF_END | BPF_FROM_BE:
692 switch (imm32) {
693 case 16:
694 /* Emit 'ror %ax, 8' to swap lower 2 bytes */
695 EMIT1(0x66);
696 if (is_ereg(dst_reg))
697 EMIT1(0x41);
698 EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
699
700 /* Emit 'movzwl eax, ax' */
701 if (is_ereg(dst_reg))
702 EMIT3(0x45, 0x0F, 0xB7);
703 else
704 EMIT2(0x0F, 0xB7);
705 EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
706 break;
707 case 32:
708 /* Emit 'bswap eax' to swap lower 4 bytes */
709 if (is_ereg(dst_reg))
710 EMIT2(0x41, 0x0F);
711 else
712 EMIT1(0x0F);
713 EMIT1(add_1reg(0xC8, dst_reg));
714 break;
715 case 64:
716 /* Emit 'bswap rax' to swap 8 bytes */
717 EMIT3(add_1mod(0x48, dst_reg), 0x0F,
718 add_1reg(0xC8, dst_reg));
719 break;
720 }
721 break;
722
723 case BPF_ALU | BPF_END | BPF_FROM_LE:
724 switch (imm32) {
725 case 16:
726 /*
727 * Emit 'movzwl eax, ax' to zero extend 16-bit
728 * into 64 bit
729 */
730 if (is_ereg(dst_reg))
731 EMIT3(0x45, 0x0F, 0xB7);
732 else
733 EMIT2(0x0F, 0xB7);
734 EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
735 break;
736 case 32:
737 /* Emit 'mov eax, eax' to clear upper 32-bits */
738 if (is_ereg(dst_reg))
739 EMIT1(0x45);
740 EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
741 break;
742 case 64:
743 /* nop */
744 break;
745 }
746 break;
747
748 /* ST: *(u8*)(dst_reg + off) = imm */
749 case BPF_ST | BPF_MEM | BPF_B:
750 if (is_ereg(dst_reg))
751 EMIT2(0x41, 0xC6);
752 else
753 EMIT1(0xC6);
754 goto st;
755 case BPF_ST | BPF_MEM | BPF_H:
756 if (is_ereg(dst_reg))
757 EMIT3(0x66, 0x41, 0xC7);
758 else
759 EMIT2(0x66, 0xC7);
760 goto st;
761 case BPF_ST | BPF_MEM | BPF_W:
762 if (is_ereg(dst_reg))
763 EMIT2(0x41, 0xC7);
764 else
765 EMIT1(0xC7);
766 goto st;
767 case BPF_ST | BPF_MEM | BPF_DW:
768 EMIT2(add_1mod(0x48, dst_reg), 0xC7);
769
770st: if (is_imm8(insn->off))
771 EMIT2(add_1reg(0x40, dst_reg), insn->off);
772 else
773 EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);
774
775 EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
776 break;
777
778 /* STX: *(u8*)(dst_reg + off) = src_reg */
779 case BPF_STX | BPF_MEM | BPF_B:
780 /* Emit 'mov byte ptr [rax + off], al' */
781 if (is_ereg(dst_reg) || is_ereg(src_reg) ||
782 /* We have to add extra byte for x86 SIL, DIL regs */
783 src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
784 EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
785 else
786 EMIT1(0x88);
787 goto stx;
788 case BPF_STX | BPF_MEM | BPF_H:
789 if (is_ereg(dst_reg) || is_ereg(src_reg))
790 EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
791 else
792 EMIT2(0x66, 0x89);
793 goto stx;
794 case BPF_STX | BPF_MEM | BPF_W:
795 if (is_ereg(dst_reg) || is_ereg(src_reg))
796 EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
797 else
798 EMIT1(0x89);
799 goto stx;
800 case BPF_STX | BPF_MEM | BPF_DW:
801 EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
802stx: if (is_imm8(insn->off))
803 EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
804 else
805 EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
806 insn->off);
807 break;
808
809 /* LDX: dst_reg = *(u8*)(src_reg + off) */
810 case BPF_LDX | BPF_MEM | BPF_B:
811 /* Emit 'movzx rax, byte ptr [rax + off]' */
812 EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
813 goto ldx;
814 case BPF_LDX | BPF_MEM | BPF_H:
815 /* Emit 'movzx rax, word ptr [rax + off]' */
816 EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
817 goto ldx;
818 case BPF_LDX | BPF_MEM | BPF_W:
819 /* Emit 'mov eax, dword ptr [rax+0x14]' */
820 if (is_ereg(dst_reg) || is_ereg(src_reg))
821 EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
822 else
823 EMIT1(0x8B);
824 goto ldx;
825 case BPF_LDX | BPF_MEM | BPF_DW:
826 /* Emit 'mov rax, qword ptr [rax+0x14]' */
827 EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
828ldx: /*
829 * If insn->off == 0 we can save one extra byte, but
830 * special case of x86 R13 which always needs an offset
831 * is not worth the hassle
832 */
833 if (is_imm8(insn->off))
834 EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off);
835 else
836 EMIT1_off32(add_2reg(0x80, src_reg, dst_reg),
837 insn->off);
838 break;
839
840 /* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */
841 case BPF_STX | BPF_XADD | BPF_W:
842 /* Emit 'lock add dword ptr [rax + off], eax' */
843 if (is_ereg(dst_reg) || is_ereg(src_reg))
844 EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01);
845 else
846 EMIT2(0xF0, 0x01);
847 goto xadd;
848 case BPF_STX | BPF_XADD | BPF_DW:
849 EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01);
850xadd: if (is_imm8(insn->off))
851 EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
852 else
853 EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
854 insn->off);
855 break;
856
857 /* call */
858 case BPF_JMP | BPF_CALL:
859 func = (u8 *) __bpf_call_base + imm32;
860 jmp_offset = func - (image + addrs[i]);
861 if (!imm32 || !is_simm32(jmp_offset)) {
862 pr_err("unsupported BPF func %d addr %p image %p\n",
863 imm32, func, image);
864 return -EINVAL;
865 }
866 EMIT1_off32(0xE8, jmp_offset);
867 break;
868
869 case BPF_JMP | BPF_TAIL_CALL:
870 emit_bpf_tail_call(&prog);
871 break;
872
873 /* cond jump */
874 case BPF_JMP | BPF_JEQ | BPF_X:
875 case BPF_JMP | BPF_JNE | BPF_X:
876 case BPF_JMP | BPF_JGT | BPF_X:
877 case BPF_JMP | BPF_JLT | BPF_X:
878 case BPF_JMP | BPF_JGE | BPF_X:
879 case BPF_JMP | BPF_JLE | BPF_X:
880 case BPF_JMP | BPF_JSGT | BPF_X:
881 case BPF_JMP | BPF_JSLT | BPF_X:
882 case BPF_JMP | BPF_JSGE | BPF_X:
883 case BPF_JMP | BPF_JSLE | BPF_X:
884 case BPF_JMP32 | BPF_JEQ | BPF_X:
885 case BPF_JMP32 | BPF_JNE | BPF_X:
886 case BPF_JMP32 | BPF_JGT | BPF_X:
887 case BPF_JMP32 | BPF_JLT | BPF_X:
888 case BPF_JMP32 | BPF_JGE | BPF_X:
889 case BPF_JMP32 | BPF_JLE | BPF_X:
890 case BPF_JMP32 | BPF_JSGT | BPF_X:
891 case BPF_JMP32 | BPF_JSLT | BPF_X:
892 case BPF_JMP32 | BPF_JSGE | BPF_X:
893 case BPF_JMP32 | BPF_JSLE | BPF_X:
894 /* cmp dst_reg, src_reg */
895 if (BPF_CLASS(insn->code) == BPF_JMP)
896 EMIT1(add_2mod(0x48, dst_reg, src_reg));
897 else if (is_ereg(dst_reg) || is_ereg(src_reg))
898 EMIT1(add_2mod(0x40, dst_reg, src_reg));
899 EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg));
900 goto emit_cond_jmp;
901
902 case BPF_JMP | BPF_JSET | BPF_X:
903 case BPF_JMP32 | BPF_JSET | BPF_X:
904 /* test dst_reg, src_reg */
905 if (BPF_CLASS(insn->code) == BPF_JMP)
906 EMIT1(add_2mod(0x48, dst_reg, src_reg));
907 else if (is_ereg(dst_reg) || is_ereg(src_reg))
908 EMIT1(add_2mod(0x40, dst_reg, src_reg));
909 EMIT2(0x85, add_2reg(0xC0, dst_reg, src_reg));
910 goto emit_cond_jmp;
911
912 case BPF_JMP | BPF_JSET | BPF_K:
913 case BPF_JMP32 | BPF_JSET | BPF_K:
914 /* test dst_reg, imm32 */
915 if (BPF_CLASS(insn->code) == BPF_JMP)
916 EMIT1(add_1mod(0x48, dst_reg));
917 else if (is_ereg(dst_reg))
918 EMIT1(add_1mod(0x40, dst_reg));
919 EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
920 goto emit_cond_jmp;
921
922 case BPF_JMP | BPF_JEQ | BPF_K:
923 case BPF_JMP | BPF_JNE | BPF_K:
924 case BPF_JMP | BPF_JGT | BPF_K:
925 case BPF_JMP | BPF_JLT | BPF_K:
926 case BPF_JMP | BPF_JGE | BPF_K:
927 case BPF_JMP | BPF_JLE | BPF_K:
928 case BPF_JMP | BPF_JSGT | BPF_K:
929 case BPF_JMP | BPF_JSLT | BPF_K:
930 case BPF_JMP | BPF_JSGE | BPF_K:
931 case BPF_JMP | BPF_JSLE | BPF_K:
932 case BPF_JMP32 | BPF_JEQ | BPF_K:
933 case BPF_JMP32 | BPF_JNE | BPF_K:
934 case BPF_JMP32 | BPF_JGT | BPF_K:
935 case BPF_JMP32 | BPF_JLT | BPF_K:
936 case BPF_JMP32 | BPF_JGE | BPF_K:
937 case BPF_JMP32 | BPF_JLE | BPF_K:
938 case BPF_JMP32 | BPF_JSGT | BPF_K:
939 case BPF_JMP32 | BPF_JSLT | BPF_K:
940 case BPF_JMP32 | BPF_JSGE | BPF_K:
941 case BPF_JMP32 | BPF_JSLE | BPF_K:
942 /* cmp dst_reg, imm8/32 */
943 if (BPF_CLASS(insn->code) == BPF_JMP)
944 EMIT1(add_1mod(0x48, dst_reg));
945 else if (is_ereg(dst_reg))
946 EMIT1(add_1mod(0x40, dst_reg));
947
948 if (is_imm8(imm32))
949 EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
950 else
951 EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);
952
953emit_cond_jmp: /* Convert BPF opcode to x86 */
954 switch (BPF_OP(insn->code)) {
955 case BPF_JEQ:
956 jmp_cond = X86_JE;
957 break;
958 case BPF_JSET:
959 case BPF_JNE:
960 jmp_cond = X86_JNE;
961 break;
962 case BPF_JGT:
963 /* GT is unsigned '>', JA in x86 */
964 jmp_cond = X86_JA;
965 break;
966 case BPF_JLT:
967 /* LT is unsigned '<', JB in x86 */
968 jmp_cond = X86_JB;
969 break;
970 case BPF_JGE:
971 /* GE is unsigned '>=', JAE in x86 */
972 jmp_cond = X86_JAE;
973 break;
974 case BPF_JLE:
975 /* LE is unsigned '<=', JBE in x86 */
976 jmp_cond = X86_JBE;
977 break;
978 case BPF_JSGT:
979 /* Signed '>', GT in x86 */
980 jmp_cond = X86_JG;
981 break;
982 case BPF_JSLT:
983 /* Signed '<', LT in x86 */
984 jmp_cond = X86_JL;
985 break;
986 case BPF_JSGE:
987 /* Signed '>=', GE in x86 */
988 jmp_cond = X86_JGE;
989 break;
990 case BPF_JSLE:
991 /* Signed '<=', LE in x86 */
992 jmp_cond = X86_JLE;
993 break;
994 default: /* to silence GCC warning */
995 return -EFAULT;
996 }
997 jmp_offset = addrs[i + insn->off] - addrs[i];
998 if (is_imm8(jmp_offset)) {
999 EMIT2(jmp_cond, jmp_offset);
1000 } else if (is_simm32(jmp_offset)) {
1001 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
1002 } else {
1003 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
1004 return -EFAULT;
1005 }
1006
1007 break;
1008
1009 case BPF_JMP | BPF_JA:
1010 if (insn->off == -1)
1011 /* -1 jmp instructions will always jump
1012 * backwards two bytes. Explicitly handling
1013 * this case avoids wasting too many passes
1014 * when there are long sequences of replaced
1015 * dead code.
1016 */
1017 jmp_offset = -2;
1018 else
1019 jmp_offset = addrs[i + insn->off] - addrs[i];
1020
1021 if (!jmp_offset)
1022 /* Optimize out nop jumps */
1023 break;
1024emit_jmp:
1025 if (is_imm8(jmp_offset)) {
1026 EMIT2(0xEB, jmp_offset);
1027 } else if (is_simm32(jmp_offset)) {
1028 EMIT1_off32(0xE9, jmp_offset);
1029 } else {
1030 pr_err("jmp gen bug %llx\n", jmp_offset);
1031 return -EFAULT;
1032 }
1033 break;
1034
1035 case BPF_JMP | BPF_EXIT:
1036 if (seen_exit) {
1037 jmp_offset = ctx->cleanup_addr - addrs[i];
1038 goto emit_jmp;
1039 }
1040 seen_exit = true;
1041 /* Update cleanup_addr */
1042 ctx->cleanup_addr = proglen;
1043 /* mov rbx, qword ptr [rbp+0] */
1044 EMIT4(0x48, 0x8B, 0x5D, 0);
1045 /* mov r13, qword ptr [rbp+8] */
1046 EMIT4(0x4C, 0x8B, 0x6D, 8);
1047 /* mov r14, qword ptr [rbp+16] */
1048 EMIT4(0x4C, 0x8B, 0x75, 16);
1049 /* mov r15, qword ptr [rbp+24] */
1050 EMIT4(0x4C, 0x8B, 0x7D, 24);
1051
1052 /* add rbp, AUX_STACK_SPACE */
1053 EMIT4(0x48, 0x83, 0xC5, AUX_STACK_SPACE);
1054 EMIT1(0xC9); /* leave */
1055 EMIT1(0xC3); /* ret */
1056 break;
1057
1058 default:
1059 /*
1060 * By design x86-64 JIT should support all BPF instructions.
1061 * This error will be seen if new instruction was added
1062 * to the interpreter, but not to the JIT, or if there is
1063 * junk in bpf_prog.
1064 */
1065 pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
1066 return -EINVAL;
1067 }
1068
1069 ilen = prog - temp;
1070 if (ilen > BPF_MAX_INSN_SIZE) {
1071 pr_err("bpf_jit: fatal insn size error\n");
1072 return -EFAULT;
1073 }
1074
1075 if (image) {
1076 if (unlikely(proglen + ilen > oldproglen)) {
1077 pr_err("bpf_jit: fatal error\n");
1078 return -EFAULT;
1079 }
1080 memcpy(image + proglen, temp, ilen);
1081 }
1082 proglen += ilen;
1083 addrs[i] = proglen;
1084 prog = temp;
1085 }
1086 return proglen;
1087}
1088
1089struct x64_jit_data {
1090 struct bpf_binary_header *header;
1091 int *addrs;
1092 u8 *image;
1093 int proglen;
1094 struct jit_context ctx;
1095};
1096
1097struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
1098{
1099 struct bpf_binary_header *header = NULL;
1100 struct bpf_prog *tmp, *orig_prog = prog;
1101 struct x64_jit_data *jit_data;
1102 int proglen, oldproglen = 0;
1103 struct jit_context ctx = {};
1104 bool tmp_blinded = false;
1105 bool extra_pass = false;
1106 u8 *image = NULL;
1107 int *addrs;
1108 int pass;
1109 int i;
1110
1111 if (!prog->jit_requested)
1112 return orig_prog;
1113
1114 tmp = bpf_jit_blind_constants(prog);
1115 /*
1116 * If blinding was requested and we failed during blinding,
1117 * we must fall back to the interpreter.
1118 */
1119 if (IS_ERR(tmp))
1120 return orig_prog;
1121 if (tmp != prog) {
1122 tmp_blinded = true;
1123 prog = tmp;
1124 }
1125
1126 jit_data = prog->aux->jit_data;
1127 if (!jit_data) {
1128 jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
1129 if (!jit_data) {
1130 prog = orig_prog;
1131 goto out;
1132 }
1133 prog->aux->jit_data = jit_data;
1134 }
1135 addrs = jit_data->addrs;
1136 if (addrs) {
1137 ctx = jit_data->ctx;
1138 oldproglen = jit_data->proglen;
1139 image = jit_data->image;
1140 header = jit_data->header;
1141 extra_pass = true;
1142 goto skip_init_addrs;
1143 }
1144 addrs = kmalloc_array(prog->len, sizeof(*addrs), GFP_KERNEL);
1145 if (!addrs) {
1146 prog = orig_prog;
1147 goto out_addrs;
1148 }
1149
1150 /*
1151 * Before first pass, make a rough estimation of addrs[]
1152 * each BPF instruction is translated to less than 64 bytes
1153 */
1154 for (proglen = 0, i = 0; i < prog->len; i++) {
1155 proglen += 64;
1156 addrs[i] = proglen;
1157 }
1158 ctx.cleanup_addr = proglen;
1159skip_init_addrs:
1160
1161 /*
1162 * JITed image shrinks with every pass and the loop iterates
1163 * until the image stops shrinking. Very large BPF programs
1164 * may converge on the last pass. In such case do one more
1165 * pass to emit the final image.
1166 */
1167 for (pass = 0; pass < 20 || image; pass++) {
1168 proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
1169 if (proglen <= 0) {
1170out_image:
1171 image = NULL;
1172 if (header)
1173 bpf_jit_binary_free(header);
1174 prog = orig_prog;
1175 goto out_addrs;
1176 }
1177 if (image) {
1178 if (proglen != oldproglen) {
1179 pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
1180 proglen, oldproglen);
1181 goto out_image;
1182 }
1183 break;
1184 }
1185 if (proglen == oldproglen) {
1186 header = bpf_jit_binary_alloc(proglen, &image,
1187 1, jit_fill_hole);
1188 if (!header) {
1189 prog = orig_prog;
1190 goto out_addrs;
1191 }
1192 }
1193 oldproglen = proglen;
1194 cond_resched();
1195 }
1196
1197 if (bpf_jit_enable > 1)
1198 bpf_jit_dump(prog->len, proglen, pass + 1, image);
1199
1200 if (image) {
1201 if (!prog->is_func || extra_pass) {
1202 bpf_jit_binary_lock_ro(header);
1203 } else {
1204 jit_data->addrs = addrs;
1205 jit_data->ctx = ctx;
1206 jit_data->proglen = proglen;
1207 jit_data->image = image;
1208 jit_data->header = header;
1209 }
1210 prog->bpf_func = (void *)image;
1211 prog->jited = 1;
1212 prog->jited_len = proglen;
1213 } else {
1214 prog = orig_prog;
1215 }
1216
1217 if (!image || !prog->is_func || extra_pass) {
1218 if (image)
1219 bpf_prog_fill_jited_linfo(prog, addrs);
1220out_addrs:
1221 kfree(addrs);
1222 kfree(jit_data);
1223 prog->aux->jit_data = NULL;
1224 }
1225out:
1226 if (tmp_blinded)
1227 bpf_jit_prog_release_other(prog, prog == orig_prog ?
1228 tmp : orig_prog);
1229 return prog;
1230}
1231