1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Just-In-Time compiler for eBPF filters on IA32 (32bit x86)
4 *
5 * Author: Wang YanQing (udknight@gmail.com)
6 * The code based on code and ideas from:
7 * Eric Dumazet (eric.dumazet@gmail.com)
8 * and from:
9 * Shubham Bansal <illusionist.neo@gmail.com>
10 */
11
12 #include <linux/netdevice.h>
13 #include <linux/filter.h>
14 #include <linux/if_vlan.h>
15 #include <asm/cacheflush.h>
16 #include <asm/set_memory.h>
17 #include <asm/nospec-branch.h>
18 #include <linux/bpf.h>
19
20 /*
21 * eBPF prog stack layout:
22 *
23 * high
24 * original ESP => +-----+
25 * | | callee saved registers
26 * +-----+
27 * | ... | eBPF JIT scratch space
28 * BPF_FP,IA32_EBP => +-----+
29 * | ... | eBPF prog stack
30 * +-----+
31 * |RSVD | JIT scratchpad
32 * current ESP => +-----+
33 * | |
34 * | ... | Function call stack
35 * | |
36 * +-----+
37 * low
38 *
39 * The callee saved registers:
40 *
41 * high
42 * original ESP => +------------------+ \
43 * | ebp | |
44 * current EBP => +------------------+ } callee saved registers
45 * | ebx,esi,edi | |
46 * +------------------+ /
47 * low
48 */
49
emit_code(u8 * ptr,u32 bytes,unsigned int len)50 static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
51 {
52 if (len == 1)
53 *ptr = bytes;
54 else if (len == 2)
55 *(u16 *)ptr = bytes;
56 else {
57 *(u32 *)ptr = bytes;
58 barrier();
59 }
60 return ptr + len;
61 }
62
63 #define EMIT(bytes, len) \
64 do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
65
66 #define EMIT1(b1) EMIT(b1, 1)
67 #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
68 #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
69 #define EMIT4(b1, b2, b3, b4) \
70 EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
71
72 #define EMIT1_off32(b1, off) \
73 do { EMIT1(b1); EMIT(off, 4); } while (0)
74 #define EMIT2_off32(b1, b2, off) \
75 do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
76 #define EMIT3_off32(b1, b2, b3, off) \
77 do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
78 #define EMIT4_off32(b1, b2, b3, b4, off) \
79 do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
80
81 #define jmp_label(label, jmp_insn_len) (label - cnt - jmp_insn_len)
82
is_imm8(int value)83 static bool is_imm8(int value)
84 {
85 return value <= 127 && value >= -128;
86 }
87
is_simm32(s64 value)88 static bool is_simm32(s64 value)
89 {
90 return value == (s64) (s32) value;
91 }
92
93 #define STACK_OFFSET(k) (k)
94 #define TCALL_CNT (MAX_BPF_JIT_REG + 0) /* Tail Call Count */
95
96 #define IA32_EAX (0x0)
97 #define IA32_EBX (0x3)
98 #define IA32_ECX (0x1)
99 #define IA32_EDX (0x2)
100 #define IA32_ESI (0x6)
101 #define IA32_EDI (0x7)
102 #define IA32_EBP (0x5)
103 #define IA32_ESP (0x4)
104
105 /*
106 * List of x86 cond jumps opcodes (. + s8)
107 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
108 */
109 #define IA32_JB 0x72
110 #define IA32_JAE 0x73
111 #define IA32_JE 0x74
112 #define IA32_JNE 0x75
113 #define IA32_JBE 0x76
114 #define IA32_JA 0x77
115 #define IA32_JL 0x7C
116 #define IA32_JGE 0x7D
117 #define IA32_JLE 0x7E
118 #define IA32_JG 0x7F
119
120 #define COND_JMP_OPCODE_INVALID (0xFF)
121
122 /*
123 * Map eBPF registers to IA32 32bit registers or stack scratch space.
124 *
125 * 1. All the registers, R0-R10, are mapped to scratch space on stack.
126 * 2. We need two 64 bit temp registers to do complex operations on eBPF
127 * registers.
128 * 3. For performance reason, the BPF_REG_AX for blinding constant, is
129 * mapped to real hardware register pair, IA32_ESI and IA32_EDI.
130 *
131 * As the eBPF registers are all 64 bit registers and IA32 has only 32 bit
132 * registers, we have to map each eBPF registers with two IA32 32 bit regs
133 * or scratch memory space and we have to build eBPF 64 bit register from those.
134 *
135 * We use IA32_EAX, IA32_EDX, IA32_ECX, IA32_EBX as temporary registers.
136 */
137 static const u8 bpf2ia32[][2] = {
138 /* Return value from in-kernel function, and exit value from eBPF */
139 [BPF_REG_0] = {STACK_OFFSET(0), STACK_OFFSET(4)},
140
141 /* The arguments from eBPF program to in-kernel function */
142 /* Stored on stack scratch space */
143 [BPF_REG_1] = {STACK_OFFSET(8), STACK_OFFSET(12)},
144 [BPF_REG_2] = {STACK_OFFSET(16), STACK_OFFSET(20)},
145 [BPF_REG_3] = {STACK_OFFSET(24), STACK_OFFSET(28)},
146 [BPF_REG_4] = {STACK_OFFSET(32), STACK_OFFSET(36)},
147 [BPF_REG_5] = {STACK_OFFSET(40), STACK_OFFSET(44)},
148
149 /* Callee saved registers that in-kernel function will preserve */
150 /* Stored on stack scratch space */
151 [BPF_REG_6] = {STACK_OFFSET(48), STACK_OFFSET(52)},
152 [BPF_REG_7] = {STACK_OFFSET(56), STACK_OFFSET(60)},
153 [BPF_REG_8] = {STACK_OFFSET(64), STACK_OFFSET(68)},
154 [BPF_REG_9] = {STACK_OFFSET(72), STACK_OFFSET(76)},
155
156 /* Read only Frame Pointer to access Stack */
157 [BPF_REG_FP] = {STACK_OFFSET(80), STACK_OFFSET(84)},
158
159 /* Temporary register for blinding constants. */
160 [BPF_REG_AX] = {IA32_ESI, IA32_EDI},
161
162 /* Tail call count. Stored on stack scratch space. */
163 [TCALL_CNT] = {STACK_OFFSET(88), STACK_OFFSET(92)},
164 };
165
166 #define dst_lo dst[0]
167 #define dst_hi dst[1]
168 #define src_lo src[0]
169 #define src_hi src[1]
170
171 #define STACK_ALIGNMENT 8
172 /*
173 * Stack space for BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4,
174 * BPF_REG_5, BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9,
175 * BPF_REG_FP, BPF_REG_AX and Tail call counts.
176 */
177 #define SCRATCH_SIZE 96
178
179 /* Total stack size used in JITed code */
180 #define _STACK_SIZE (stack_depth + SCRATCH_SIZE)
181
182 #define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT)
183
184 /* Get the offset of eBPF REGISTERs stored on scratch space. */
185 #define STACK_VAR(off) (off)
186
187 /* Encode 'dst_reg' register into IA32 opcode 'byte' */
add_1reg(u8 byte,u32 dst_reg)188 static u8 add_1reg(u8 byte, u32 dst_reg)
189 {
190 return byte + dst_reg;
191 }
192
193 /* Encode 'dst_reg' and 'src_reg' registers into IA32 opcode 'byte' */
add_2reg(u8 byte,u32 dst_reg,u32 src_reg)194 static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
195 {
196 return byte + dst_reg + (src_reg << 3);
197 }
198
jit_fill_hole(void * area,unsigned int size)199 static void jit_fill_hole(void *area, unsigned int size)
200 {
201 /* Fill whole space with int3 instructions */
202 memset(area, 0xcc, size);
203 }
204
emit_ia32_mov_i(const u8 dst,const u32 val,bool dstk,u8 ** pprog)205 static inline void emit_ia32_mov_i(const u8 dst, const u32 val, bool dstk,
206 u8 **pprog)
207 {
208 u8 *prog = *pprog;
209 int cnt = 0;
210
211 if (dstk) {
212 if (val == 0) {
213 /* xor eax,eax */
214 EMIT2(0x33, add_2reg(0xC0, IA32_EAX, IA32_EAX));
215 /* mov dword ptr [ebp+off],eax */
216 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
217 STACK_VAR(dst));
218 } else {
219 EMIT3_off32(0xC7, add_1reg(0x40, IA32_EBP),
220 STACK_VAR(dst), val);
221 }
222 } else {
223 if (val == 0)
224 EMIT2(0x33, add_2reg(0xC0, dst, dst));
225 else
226 EMIT2_off32(0xC7, add_1reg(0xC0, dst),
227 val);
228 }
229 *pprog = prog;
230 }
231
232 /* dst = imm (4 bytes)*/
emit_ia32_mov_r(const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)233 static inline void emit_ia32_mov_r(const u8 dst, const u8 src, bool dstk,
234 bool sstk, u8 **pprog)
235 {
236 u8 *prog = *pprog;
237 int cnt = 0;
238 u8 sreg = sstk ? IA32_EAX : src;
239
240 if (sstk)
241 /* mov eax,dword ptr [ebp+off] */
242 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(src));
243 if (dstk)
244 /* mov dword ptr [ebp+off],eax */
245 EMIT3(0x89, add_2reg(0x40, IA32_EBP, sreg), STACK_VAR(dst));
246 else
247 /* mov dst,sreg */
248 EMIT2(0x89, add_2reg(0xC0, dst, sreg));
249
250 *pprog = prog;
251 }
252
253 /* dst = src */
emit_ia32_mov_r64(const bool is64,const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog,const struct bpf_prog_aux * aux)254 static inline void emit_ia32_mov_r64(const bool is64, const u8 dst[],
255 const u8 src[], bool dstk,
256 bool sstk, u8 **pprog,
257 const struct bpf_prog_aux *aux)
258 {
259 emit_ia32_mov_r(dst_lo, src_lo, dstk, sstk, pprog);
260 if (is64)
261 /* complete 8 byte move */
262 emit_ia32_mov_r(dst_hi, src_hi, dstk, sstk, pprog);
263 else if (!aux->verifier_zext)
264 /* zero out high 4 bytes */
265 emit_ia32_mov_i(dst_hi, 0, dstk, pprog);
266 }
267
268 /* Sign extended move */
emit_ia32_mov_i64(const bool is64,const u8 dst[],const u32 val,bool dstk,u8 ** pprog)269 static inline void emit_ia32_mov_i64(const bool is64, const u8 dst[],
270 const u32 val, bool dstk, u8 **pprog)
271 {
272 u32 hi = 0;
273
274 if (is64 && (val & (1<<31)))
275 hi = (u32)~0;
276 emit_ia32_mov_i(dst_lo, val, dstk, pprog);
277 emit_ia32_mov_i(dst_hi, hi, dstk, pprog);
278 }
279
280 /*
281 * ALU operation (32 bit)
282 * dst = dst * src
283 */
emit_ia32_mul_r(const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)284 static inline void emit_ia32_mul_r(const u8 dst, const u8 src, bool dstk,
285 bool sstk, u8 **pprog)
286 {
287 u8 *prog = *pprog;
288 int cnt = 0;
289 u8 sreg = sstk ? IA32_ECX : src;
290
291 if (sstk)
292 /* mov ecx,dword ptr [ebp+off] */
293 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src));
294
295 if (dstk)
296 /* mov eax,dword ptr [ebp+off] */
297 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
298 else
299 /* mov eax,dst */
300 EMIT2(0x8B, add_2reg(0xC0, dst, IA32_EAX));
301
302
303 EMIT2(0xF7, add_1reg(0xE0, sreg));
304
305 if (dstk)
306 /* mov dword ptr [ebp+off],eax */
307 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
308 STACK_VAR(dst));
309 else
310 /* mov dst,eax */
311 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EAX));
312
313 *pprog = prog;
314 }
315
emit_ia32_to_le_r64(const u8 dst[],s32 val,bool dstk,u8 ** pprog,const struct bpf_prog_aux * aux)316 static inline void emit_ia32_to_le_r64(const u8 dst[], s32 val,
317 bool dstk, u8 **pprog,
318 const struct bpf_prog_aux *aux)
319 {
320 u8 *prog = *pprog;
321 int cnt = 0;
322 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
323 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
324
325 if (dstk && val != 64) {
326 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
327 STACK_VAR(dst_lo));
328 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
329 STACK_VAR(dst_hi));
330 }
331 switch (val) {
332 case 16:
333 /*
334 * Emit 'movzwl eax,ax' to zero extend 16-bit
335 * into 64 bit
336 */
337 EMIT2(0x0F, 0xB7);
338 EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
339 if (!aux->verifier_zext)
340 /* xor dreg_hi,dreg_hi */
341 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
342 break;
343 case 32:
344 if (!aux->verifier_zext)
345 /* xor dreg_hi,dreg_hi */
346 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
347 break;
348 case 64:
349 /* nop */
350 break;
351 }
352
353 if (dstk && val != 64) {
354 /* mov dword ptr [ebp+off],dreg_lo */
355 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
356 STACK_VAR(dst_lo));
357 /* mov dword ptr [ebp+off],dreg_hi */
358 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
359 STACK_VAR(dst_hi));
360 }
361 *pprog = prog;
362 }
363
emit_ia32_to_be_r64(const u8 dst[],s32 val,bool dstk,u8 ** pprog,const struct bpf_prog_aux * aux)364 static inline void emit_ia32_to_be_r64(const u8 dst[], s32 val,
365 bool dstk, u8 **pprog,
366 const struct bpf_prog_aux *aux)
367 {
368 u8 *prog = *pprog;
369 int cnt = 0;
370 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
371 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
372
373 if (dstk) {
374 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
375 STACK_VAR(dst_lo));
376 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
377 STACK_VAR(dst_hi));
378 }
379 switch (val) {
380 case 16:
381 /* Emit 'ror %ax, 8' to swap lower 2 bytes */
382 EMIT1(0x66);
383 EMIT3(0xC1, add_1reg(0xC8, dreg_lo), 8);
384
385 EMIT2(0x0F, 0xB7);
386 EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
387
388 if (!aux->verifier_zext)
389 /* xor dreg_hi,dreg_hi */
390 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
391 break;
392 case 32:
393 /* Emit 'bswap eax' to swap lower 4 bytes */
394 EMIT1(0x0F);
395 EMIT1(add_1reg(0xC8, dreg_lo));
396
397 if (!aux->verifier_zext)
398 /* xor dreg_hi,dreg_hi */
399 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
400 break;
401 case 64:
402 /* Emit 'bswap eax' to swap lower 4 bytes */
403 EMIT1(0x0F);
404 EMIT1(add_1reg(0xC8, dreg_lo));
405
406 /* Emit 'bswap edx' to swap lower 4 bytes */
407 EMIT1(0x0F);
408 EMIT1(add_1reg(0xC8, dreg_hi));
409
410 /* mov ecx,dreg_hi */
411 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, dreg_hi));
412 /* mov dreg_hi,dreg_lo */
413 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
414 /* mov dreg_lo,ecx */
415 EMIT2(0x89, add_2reg(0xC0, dreg_lo, IA32_ECX));
416
417 break;
418 }
419 if (dstk) {
420 /* mov dword ptr [ebp+off],dreg_lo */
421 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
422 STACK_VAR(dst_lo));
423 /* mov dword ptr [ebp+off],dreg_hi */
424 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
425 STACK_VAR(dst_hi));
426 }
427 *pprog = prog;
428 }
429
430 /*
431 * ALU operation (32 bit)
432 * dst = dst (div|mod) src
433 */
emit_ia32_div_mod_r(const u8 op,const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)434 static inline void emit_ia32_div_mod_r(const u8 op, const u8 dst, const u8 src,
435 bool dstk, bool sstk, u8 **pprog)
436 {
437 u8 *prog = *pprog;
438 int cnt = 0;
439
440 if (sstk)
441 /* mov ecx,dword ptr [ebp+off] */
442 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
443 STACK_VAR(src));
444 else if (src != IA32_ECX)
445 /* mov ecx,src */
446 EMIT2(0x8B, add_2reg(0xC0, src, IA32_ECX));
447
448 if (dstk)
449 /* mov eax,dword ptr [ebp+off] */
450 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
451 STACK_VAR(dst));
452 else
453 /* mov eax,dst */
454 EMIT2(0x8B, add_2reg(0xC0, dst, IA32_EAX));
455
456 /* xor edx,edx */
457 EMIT2(0x31, add_2reg(0xC0, IA32_EDX, IA32_EDX));
458 /* div ecx */
459 EMIT2(0xF7, add_1reg(0xF0, IA32_ECX));
460
461 if (op == BPF_MOD) {
462 if (dstk)
463 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
464 STACK_VAR(dst));
465 else
466 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EDX));
467 } else {
468 if (dstk)
469 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
470 STACK_VAR(dst));
471 else
472 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EAX));
473 }
474 *pprog = prog;
475 }
476
477 /*
478 * ALU operation (32 bit)
479 * dst = dst (shift) src
480 */
emit_ia32_shift_r(const u8 op,const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)481 static inline void emit_ia32_shift_r(const u8 op, const u8 dst, const u8 src,
482 bool dstk, bool sstk, u8 **pprog)
483 {
484 u8 *prog = *pprog;
485 int cnt = 0;
486 u8 dreg = dstk ? IA32_EAX : dst;
487 u8 b2;
488
489 if (dstk)
490 /* mov eax,dword ptr [ebp+off] */
491 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
492
493 if (sstk)
494 /* mov ecx,dword ptr [ebp+off] */
495 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src));
496 else if (src != IA32_ECX)
497 /* mov ecx,src */
498 EMIT2(0x8B, add_2reg(0xC0, src, IA32_ECX));
499
500 switch (op) {
501 case BPF_LSH:
502 b2 = 0xE0; break;
503 case BPF_RSH:
504 b2 = 0xE8; break;
505 case BPF_ARSH:
506 b2 = 0xF8; break;
507 default:
508 return;
509 }
510 EMIT2(0xD3, add_1reg(b2, dreg));
511
512 if (dstk)
513 /* mov dword ptr [ebp+off],dreg */
514 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg), STACK_VAR(dst));
515 *pprog = prog;
516 }
517
518 /*
519 * ALU operation (32 bit)
520 * dst = dst (op) src
521 */
emit_ia32_alu_r(const bool is64,const bool hi,const u8 op,const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)522 static inline void emit_ia32_alu_r(const bool is64, const bool hi, const u8 op,
523 const u8 dst, const u8 src, bool dstk,
524 bool sstk, u8 **pprog)
525 {
526 u8 *prog = *pprog;
527 int cnt = 0;
528 u8 sreg = sstk ? IA32_EAX : src;
529 u8 dreg = dstk ? IA32_EDX : dst;
530
531 if (sstk)
532 /* mov eax,dword ptr [ebp+off] */
533 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(src));
534
535 if (dstk)
536 /* mov eax,dword ptr [ebp+off] */
537 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(dst));
538
539 switch (BPF_OP(op)) {
540 /* dst = dst + src */
541 case BPF_ADD:
542 if (hi && is64)
543 EMIT2(0x11, add_2reg(0xC0, dreg, sreg));
544 else
545 EMIT2(0x01, add_2reg(0xC0, dreg, sreg));
546 break;
547 /* dst = dst - src */
548 case BPF_SUB:
549 if (hi && is64)
550 EMIT2(0x19, add_2reg(0xC0, dreg, sreg));
551 else
552 EMIT2(0x29, add_2reg(0xC0, dreg, sreg));
553 break;
554 /* dst = dst | src */
555 case BPF_OR:
556 EMIT2(0x09, add_2reg(0xC0, dreg, sreg));
557 break;
558 /* dst = dst & src */
559 case BPF_AND:
560 EMIT2(0x21, add_2reg(0xC0, dreg, sreg));
561 break;
562 /* dst = dst ^ src */
563 case BPF_XOR:
564 EMIT2(0x31, add_2reg(0xC0, dreg, sreg));
565 break;
566 }
567
568 if (dstk)
569 /* mov dword ptr [ebp+off],dreg */
570 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg),
571 STACK_VAR(dst));
572 *pprog = prog;
573 }
574
575 /* ALU operation (64 bit) */
emit_ia32_alu_r64(const bool is64,const u8 op,const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog,const struct bpf_prog_aux * aux)576 static inline void emit_ia32_alu_r64(const bool is64, const u8 op,
577 const u8 dst[], const u8 src[],
578 bool dstk, bool sstk,
579 u8 **pprog, const struct bpf_prog_aux *aux)
580 {
581 u8 *prog = *pprog;
582
583 emit_ia32_alu_r(is64, false, op, dst_lo, src_lo, dstk, sstk, &prog);
584 if (is64)
585 emit_ia32_alu_r(is64, true, op, dst_hi, src_hi, dstk, sstk,
586 &prog);
587 else if (!aux->verifier_zext)
588 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
589 *pprog = prog;
590 }
591
592 /*
593 * ALU operation (32 bit)
594 * dst = dst (op) val
595 */
emit_ia32_alu_i(const bool is64,const bool hi,const u8 op,const u8 dst,const s32 val,bool dstk,u8 ** pprog)596 static inline void emit_ia32_alu_i(const bool is64, const bool hi, const u8 op,
597 const u8 dst, const s32 val, bool dstk,
598 u8 **pprog)
599 {
600 u8 *prog = *pprog;
601 int cnt = 0;
602 u8 dreg = dstk ? IA32_EAX : dst;
603 u8 sreg = IA32_EDX;
604
605 if (dstk)
606 /* mov eax,dword ptr [ebp+off] */
607 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
608
609 if (!is_imm8(val))
610 /* mov edx,imm32*/
611 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EDX), val);
612
613 switch (op) {
614 /* dst = dst + val */
615 case BPF_ADD:
616 if (hi && is64) {
617 if (is_imm8(val))
618 EMIT3(0x83, add_1reg(0xD0, dreg), val);
619 else
620 EMIT2(0x11, add_2reg(0xC0, dreg, sreg));
621 } else {
622 if (is_imm8(val))
623 EMIT3(0x83, add_1reg(0xC0, dreg), val);
624 else
625 EMIT2(0x01, add_2reg(0xC0, dreg, sreg));
626 }
627 break;
628 /* dst = dst - val */
629 case BPF_SUB:
630 if (hi && is64) {
631 if (is_imm8(val))
632 EMIT3(0x83, add_1reg(0xD8, dreg), val);
633 else
634 EMIT2(0x19, add_2reg(0xC0, dreg, sreg));
635 } else {
636 if (is_imm8(val))
637 EMIT3(0x83, add_1reg(0xE8, dreg), val);
638 else
639 EMIT2(0x29, add_2reg(0xC0, dreg, sreg));
640 }
641 break;
642 /* dst = dst | val */
643 case BPF_OR:
644 if (is_imm8(val))
645 EMIT3(0x83, add_1reg(0xC8, dreg), val);
646 else
647 EMIT2(0x09, add_2reg(0xC0, dreg, sreg));
648 break;
649 /* dst = dst & val */
650 case BPF_AND:
651 if (is_imm8(val))
652 EMIT3(0x83, add_1reg(0xE0, dreg), val);
653 else
654 EMIT2(0x21, add_2reg(0xC0, dreg, sreg));
655 break;
656 /* dst = dst ^ val */
657 case BPF_XOR:
658 if (is_imm8(val))
659 EMIT3(0x83, add_1reg(0xF0, dreg), val);
660 else
661 EMIT2(0x31, add_2reg(0xC0, dreg, sreg));
662 break;
663 case BPF_NEG:
664 EMIT2(0xF7, add_1reg(0xD8, dreg));
665 break;
666 }
667
668 if (dstk)
669 /* mov dword ptr [ebp+off],dreg */
670 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg),
671 STACK_VAR(dst));
672 *pprog = prog;
673 }
674
675 /* ALU operation (64 bit) */
emit_ia32_alu_i64(const bool is64,const u8 op,const u8 dst[],const u32 val,bool dstk,u8 ** pprog,const struct bpf_prog_aux * aux)676 static inline void emit_ia32_alu_i64(const bool is64, const u8 op,
677 const u8 dst[], const u32 val,
678 bool dstk, u8 **pprog,
679 const struct bpf_prog_aux *aux)
680 {
681 u8 *prog = *pprog;
682 u32 hi = 0;
683
684 if (is64 && (val & (1<<31)))
685 hi = (u32)~0;
686
687 emit_ia32_alu_i(is64, false, op, dst_lo, val, dstk, &prog);
688 if (is64)
689 emit_ia32_alu_i(is64, true, op, dst_hi, hi, dstk, &prog);
690 else if (!aux->verifier_zext)
691 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
692
693 *pprog = prog;
694 }
695
696 /* dst = ~dst (64 bit) */
emit_ia32_neg64(const u8 dst[],bool dstk,u8 ** pprog)697 static inline void emit_ia32_neg64(const u8 dst[], bool dstk, u8 **pprog)
698 {
699 u8 *prog = *pprog;
700 int cnt = 0;
701 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
702 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
703
704 if (dstk) {
705 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
706 STACK_VAR(dst_lo));
707 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
708 STACK_VAR(dst_hi));
709 }
710
711 /* neg dreg_lo */
712 EMIT2(0xF7, add_1reg(0xD8, dreg_lo));
713 /* adc dreg_hi,0x0 */
714 EMIT3(0x83, add_1reg(0xD0, dreg_hi), 0x00);
715 /* neg dreg_hi */
716 EMIT2(0xF7, add_1reg(0xD8, dreg_hi));
717
718 if (dstk) {
719 /* mov dword ptr [ebp+off],dreg_lo */
720 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
721 STACK_VAR(dst_lo));
722 /* mov dword ptr [ebp+off],dreg_hi */
723 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
724 STACK_VAR(dst_hi));
725 }
726 *pprog = prog;
727 }
728
729 /* dst = dst << src */
emit_ia32_lsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)730 static inline void emit_ia32_lsh_r64(const u8 dst[], const u8 src[],
731 bool dstk, bool sstk, u8 **pprog)
732 {
733 u8 *prog = *pprog;
734 int cnt = 0;
735 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
736 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
737
738 if (dstk) {
739 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
740 STACK_VAR(dst_lo));
741 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
742 STACK_VAR(dst_hi));
743 }
744
745 if (sstk)
746 /* mov ecx,dword ptr [ebp+off] */
747 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
748 STACK_VAR(src_lo));
749 else
750 /* mov ecx,src_lo */
751 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
752
753 /* shld dreg_hi,dreg_lo,cl */
754 EMIT3(0x0F, 0xA5, add_2reg(0xC0, dreg_hi, dreg_lo));
755 /* shl dreg_lo,cl */
756 EMIT2(0xD3, add_1reg(0xE0, dreg_lo));
757
758 /* if ecx >= 32, mov dreg_lo into dreg_hi and clear dreg_lo */
759
760 /* cmp ecx,32 */
761 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
762 /* skip the next two instructions (4 bytes) when < 32 */
763 EMIT2(IA32_JB, 4);
764
765 /* mov dreg_hi,dreg_lo */
766 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
767 /* xor dreg_lo,dreg_lo */
768 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
769
770 if (dstk) {
771 /* mov dword ptr [ebp+off],dreg_lo */
772 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
773 STACK_VAR(dst_lo));
774 /* mov dword ptr [ebp+off],dreg_hi */
775 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
776 STACK_VAR(dst_hi));
777 }
778 /* out: */
779 *pprog = prog;
780 }
781
782 /* dst = dst >> src (signed)*/
emit_ia32_arsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)783 static inline void emit_ia32_arsh_r64(const u8 dst[], const u8 src[],
784 bool dstk, bool sstk, u8 **pprog)
785 {
786 u8 *prog = *pprog;
787 int cnt = 0;
788 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
789 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
790
791 if (dstk) {
792 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
793 STACK_VAR(dst_lo));
794 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
795 STACK_VAR(dst_hi));
796 }
797
798 if (sstk)
799 /* mov ecx,dword ptr [ebp+off] */
800 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
801 STACK_VAR(src_lo));
802 else
803 /* mov ecx,src_lo */
804 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
805
806 /* shrd dreg_lo,dreg_hi,cl */
807 EMIT3(0x0F, 0xAD, add_2reg(0xC0, dreg_lo, dreg_hi));
808 /* sar dreg_hi,cl */
809 EMIT2(0xD3, add_1reg(0xF8, dreg_hi));
810
811 /* if ecx >= 32, mov dreg_hi to dreg_lo and set/clear dreg_hi depending on sign */
812
813 /* cmp ecx,32 */
814 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
815 /* skip the next two instructions (5 bytes) when < 32 */
816 EMIT2(IA32_JB, 5);
817
818 /* mov dreg_lo,dreg_hi */
819 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
820 /* sar dreg_hi,31 */
821 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
822
823 if (dstk) {
824 /* mov dword ptr [ebp+off],dreg_lo */
825 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
826 STACK_VAR(dst_lo));
827 /* mov dword ptr [ebp+off],dreg_hi */
828 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
829 STACK_VAR(dst_hi));
830 }
831 /* out: */
832 *pprog = prog;
833 }
834
835 /* dst = dst >> src */
emit_ia32_rsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)836 static inline void emit_ia32_rsh_r64(const u8 dst[], const u8 src[], bool dstk,
837 bool sstk, u8 **pprog)
838 {
839 u8 *prog = *pprog;
840 int cnt = 0;
841 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
842 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
843
844 if (dstk) {
845 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
846 STACK_VAR(dst_lo));
847 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
848 STACK_VAR(dst_hi));
849 }
850
851 if (sstk)
852 /* mov ecx,dword ptr [ebp+off] */
853 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
854 STACK_VAR(src_lo));
855 else
856 /* mov ecx,src_lo */
857 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
858
859 /* shrd dreg_lo,dreg_hi,cl */
860 EMIT3(0x0F, 0xAD, add_2reg(0xC0, dreg_lo, dreg_hi));
861 /* shr dreg_hi,cl */
862 EMIT2(0xD3, add_1reg(0xE8, dreg_hi));
863
864 /* if ecx >= 32, mov dreg_hi to dreg_lo and clear dreg_hi */
865
866 /* cmp ecx,32 */
867 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
868 /* skip the next two instructions (4 bytes) when < 32 */
869 EMIT2(IA32_JB, 4);
870
871 /* mov dreg_lo,dreg_hi */
872 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
873 /* xor dreg_hi,dreg_hi */
874 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
875
876 if (dstk) {
877 /* mov dword ptr [ebp+off],dreg_lo */
878 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
879 STACK_VAR(dst_lo));
880 /* mov dword ptr [ebp+off],dreg_hi */
881 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
882 STACK_VAR(dst_hi));
883 }
884 /* out: */
885 *pprog = prog;
886 }
887
888 /* dst = dst << val */
emit_ia32_lsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)889 static inline void emit_ia32_lsh_i64(const u8 dst[], const u32 val,
890 bool dstk, u8 **pprog)
891 {
892 u8 *prog = *pprog;
893 int cnt = 0;
894 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
895 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
896
897 if (dstk) {
898 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
899 STACK_VAR(dst_lo));
900 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
901 STACK_VAR(dst_hi));
902 }
903 /* Do LSH operation */
904 if (val < 32) {
905 /* shld dreg_hi,dreg_lo,imm8 */
906 EMIT4(0x0F, 0xA4, add_2reg(0xC0, dreg_hi, dreg_lo), val);
907 /* shl dreg_lo,imm8 */
908 EMIT3(0xC1, add_1reg(0xE0, dreg_lo), val);
909 } else if (val >= 32 && val < 64) {
910 u32 value = val - 32;
911
912 /* shl dreg_lo,imm8 */
913 EMIT3(0xC1, add_1reg(0xE0, dreg_lo), value);
914 /* mov dreg_hi,dreg_lo */
915 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
916 /* xor dreg_lo,dreg_lo */
917 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
918 } else {
919 /* xor dreg_lo,dreg_lo */
920 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
921 /* xor dreg_hi,dreg_hi */
922 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
923 }
924
925 if (dstk) {
926 /* mov dword ptr [ebp+off],dreg_lo */
927 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
928 STACK_VAR(dst_lo));
929 /* mov dword ptr [ebp+off],dreg_hi */
930 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
931 STACK_VAR(dst_hi));
932 }
933 *pprog = prog;
934 }
935
936 /* dst = dst >> val */
emit_ia32_rsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)937 static inline void emit_ia32_rsh_i64(const u8 dst[], const u32 val,
938 bool dstk, u8 **pprog)
939 {
940 u8 *prog = *pprog;
941 int cnt = 0;
942 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
943 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
944
945 if (dstk) {
946 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
947 STACK_VAR(dst_lo));
948 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
949 STACK_VAR(dst_hi));
950 }
951
952 /* Do RSH operation */
953 if (val < 32) {
954 /* shrd dreg_lo,dreg_hi,imm8 */
955 EMIT4(0x0F, 0xAC, add_2reg(0xC0, dreg_lo, dreg_hi), val);
956 /* shr dreg_hi,imm8 */
957 EMIT3(0xC1, add_1reg(0xE8, dreg_hi), val);
958 } else if (val >= 32 && val < 64) {
959 u32 value = val - 32;
960
961 /* shr dreg_hi,imm8 */
962 EMIT3(0xC1, add_1reg(0xE8, dreg_hi), value);
963 /* mov dreg_lo,dreg_hi */
964 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
965 /* xor dreg_hi,dreg_hi */
966 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
967 } else {
968 /* xor dreg_lo,dreg_lo */
969 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
970 /* xor dreg_hi,dreg_hi */
971 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
972 }
973
974 if (dstk) {
975 /* mov dword ptr [ebp+off],dreg_lo */
976 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
977 STACK_VAR(dst_lo));
978 /* mov dword ptr [ebp+off],dreg_hi */
979 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
980 STACK_VAR(dst_hi));
981 }
982 *pprog = prog;
983 }
984
985 /* dst = dst >> val (signed) */
emit_ia32_arsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)986 static inline void emit_ia32_arsh_i64(const u8 dst[], const u32 val,
987 bool dstk, u8 **pprog)
988 {
989 u8 *prog = *pprog;
990 int cnt = 0;
991 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
992 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
993
994 if (dstk) {
995 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
996 STACK_VAR(dst_lo));
997 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
998 STACK_VAR(dst_hi));
999 }
1000 /* Do RSH operation */
1001 if (val < 32) {
1002 /* shrd dreg_lo,dreg_hi,imm8 */
1003 EMIT4(0x0F, 0xAC, add_2reg(0xC0, dreg_lo, dreg_hi), val);
1004 /* ashr dreg_hi,imm8 */
1005 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), val);
1006 } else if (val >= 32 && val < 64) {
1007 u32 value = val - 32;
1008
1009 /* ashr dreg_hi,imm8 */
1010 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), value);
1011 /* mov dreg_lo,dreg_hi */
1012 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
1013
1014 /* ashr dreg_hi,imm8 */
1015 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
1016 } else {
1017 /* ashr dreg_hi,imm8 */
1018 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
1019 /* mov dreg_lo,dreg_hi */
1020 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
1021 }
1022
1023 if (dstk) {
1024 /* mov dword ptr [ebp+off],dreg_lo */
1025 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
1026 STACK_VAR(dst_lo));
1027 /* mov dword ptr [ebp+off],dreg_hi */
1028 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
1029 STACK_VAR(dst_hi));
1030 }
1031 *pprog = prog;
1032 }
1033
emit_ia32_mul_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)1034 static inline void emit_ia32_mul_r64(const u8 dst[], const u8 src[], bool dstk,
1035 bool sstk, u8 **pprog)
1036 {
1037 u8 *prog = *pprog;
1038 int cnt = 0;
1039
1040 if (dstk)
1041 /* mov eax,dword ptr [ebp+off] */
1042 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1043 STACK_VAR(dst_hi));
1044 else
1045 /* mov eax,dst_hi */
1046 EMIT2(0x8B, add_2reg(0xC0, dst_hi, IA32_EAX));
1047
1048 if (sstk)
1049 /* mul dword ptr [ebp+off] */
1050 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_lo));
1051 else
1052 /* mul src_lo */
1053 EMIT2(0xF7, add_1reg(0xE0, src_lo));
1054
1055 /* mov ecx,eax */
1056 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1057
1058 if (dstk)
1059 /* mov eax,dword ptr [ebp+off] */
1060 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1061 STACK_VAR(dst_lo));
1062 else
1063 /* mov eax,dst_lo */
1064 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1065
1066 if (sstk)
1067 /* mul dword ptr [ebp+off] */
1068 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_hi));
1069 else
1070 /* mul src_hi */
1071 EMIT2(0xF7, add_1reg(0xE0, src_hi));
1072
1073 /* add eax,eax */
1074 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1075
1076 if (dstk)
1077 /* mov eax,dword ptr [ebp+off] */
1078 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1079 STACK_VAR(dst_lo));
1080 else
1081 /* mov eax,dst_lo */
1082 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1083
1084 if (sstk)
1085 /* mul dword ptr [ebp+off] */
1086 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_lo));
1087 else
1088 /* mul src_lo */
1089 EMIT2(0xF7, add_1reg(0xE0, src_lo));
1090
1091 /* add ecx,edx */
1092 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EDX));
1093
1094 if (dstk) {
1095 /* mov dword ptr [ebp+off],eax */
1096 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1097 STACK_VAR(dst_lo));
1098 /* mov dword ptr [ebp+off],ecx */
1099 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX),
1100 STACK_VAR(dst_hi));
1101 } else {
1102 /* mov dst_lo,eax */
1103 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EAX));
1104 /* mov dst_hi,ecx */
1105 EMIT2(0x89, add_2reg(0xC0, dst_hi, IA32_ECX));
1106 }
1107
1108 *pprog = prog;
1109 }
1110
emit_ia32_mul_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)1111 static inline void emit_ia32_mul_i64(const u8 dst[], const u32 val,
1112 bool dstk, u8 **pprog)
1113 {
1114 u8 *prog = *pprog;
1115 int cnt = 0;
1116 u32 hi;
1117
1118 hi = val & (1<<31) ? (u32)~0 : 0;
1119 /* movl eax,imm32 */
1120 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), val);
1121 if (dstk)
1122 /* mul dword ptr [ebp+off] */
1123 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_hi));
1124 else
1125 /* mul dst_hi */
1126 EMIT2(0xF7, add_1reg(0xE0, dst_hi));
1127
1128 /* mov ecx,eax */
1129 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1130
1131 /* movl eax,imm32 */
1132 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), hi);
1133 if (dstk)
1134 /* mul dword ptr [ebp+off] */
1135 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_lo));
1136 else
1137 /* mul dst_lo */
1138 EMIT2(0xF7, add_1reg(0xE0, dst_lo));
1139 /* add ecx,eax */
1140 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1141
1142 /* movl eax,imm32 */
1143 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), val);
1144 if (dstk)
1145 /* mul dword ptr [ebp+off] */
1146 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_lo));
1147 else
1148 /* mul dst_lo */
1149 EMIT2(0xF7, add_1reg(0xE0, dst_lo));
1150
1151 /* add ecx,edx */
1152 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EDX));
1153
1154 if (dstk) {
1155 /* mov dword ptr [ebp+off],eax */
1156 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1157 STACK_VAR(dst_lo));
1158 /* mov dword ptr [ebp+off],ecx */
1159 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX),
1160 STACK_VAR(dst_hi));
1161 } else {
1162 /* mov dword ptr [ebp+off],eax */
1163 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EAX));
1164 /* mov dword ptr [ebp+off],ecx */
1165 EMIT2(0x89, add_2reg(0xC0, dst_hi, IA32_ECX));
1166 }
1167
1168 *pprog = prog;
1169 }
1170
bpf_size_to_x86_bytes(int bpf_size)1171 static int bpf_size_to_x86_bytes(int bpf_size)
1172 {
1173 if (bpf_size == BPF_W)
1174 return 4;
1175 else if (bpf_size == BPF_H)
1176 return 2;
1177 else if (bpf_size == BPF_B)
1178 return 1;
1179 else if (bpf_size == BPF_DW)
1180 return 4; /* imm32 */
1181 else
1182 return 0;
1183 }
1184
1185 struct jit_context {
1186 int cleanup_addr; /* Epilogue code offset */
1187 };
1188
1189 /* Maximum number of bytes emitted while JITing one eBPF insn */
1190 #define BPF_MAX_INSN_SIZE 128
1191 #define BPF_INSN_SAFETY 64
1192
1193 #define PROLOGUE_SIZE 35
1194
1195 /*
1196 * Emit prologue code for BPF program and check it's size.
1197 * bpf_tail_call helper will skip it while jumping into another program.
1198 */
emit_prologue(u8 ** pprog,u32 stack_depth)1199 static void emit_prologue(u8 **pprog, u32 stack_depth)
1200 {
1201 u8 *prog = *pprog;
1202 int cnt = 0;
1203 const u8 *r1 = bpf2ia32[BPF_REG_1];
1204 const u8 fplo = bpf2ia32[BPF_REG_FP][0];
1205 const u8 fphi = bpf2ia32[BPF_REG_FP][1];
1206 const u8 *tcc = bpf2ia32[TCALL_CNT];
1207
1208 /* push ebp */
1209 EMIT1(0x55);
1210 /* mov ebp,esp */
1211 EMIT2(0x89, 0xE5);
1212 /* push edi */
1213 EMIT1(0x57);
1214 /* push esi */
1215 EMIT1(0x56);
1216 /* push ebx */
1217 EMIT1(0x53);
1218
1219 /* sub esp,STACK_SIZE */
1220 EMIT2_off32(0x81, 0xEC, STACK_SIZE);
1221 /* sub ebp,SCRATCH_SIZE+12*/
1222 EMIT3(0x83, add_1reg(0xE8, IA32_EBP), SCRATCH_SIZE + 12);
1223 /* xor ebx,ebx */
1224 EMIT2(0x31, add_2reg(0xC0, IA32_EBX, IA32_EBX));
1225
1226 /* Set up BPF prog stack base register */
1227 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBP), STACK_VAR(fplo));
1228 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(fphi));
1229
1230 /* Move BPF_CTX (EAX) to BPF_REG_R1 */
1231 /* mov dword ptr [ebp+off],eax */
1232 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r1[0]));
1233 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(r1[1]));
1234
1235 /* Initialize Tail Count */
1236 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[0]));
1237 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1238
1239 BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
1240 *pprog = prog;
1241 }
1242
1243 /* Emit epilogue code for BPF program */
emit_epilogue(u8 ** pprog,u32 stack_depth)1244 static void emit_epilogue(u8 **pprog, u32 stack_depth)
1245 {
1246 u8 *prog = *pprog;
1247 const u8 *r0 = bpf2ia32[BPF_REG_0];
1248 int cnt = 0;
1249
1250 /* mov eax,dword ptr [ebp+off]*/
1251 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r0[0]));
1252 /* mov edx,dword ptr [ebp+off]*/
1253 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(r0[1]));
1254
1255 /* add ebp,SCRATCH_SIZE+12*/
1256 EMIT3(0x83, add_1reg(0xC0, IA32_EBP), SCRATCH_SIZE + 12);
1257
1258 /* mov ebx,dword ptr [ebp-12]*/
1259 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EBX), -12);
1260 /* mov esi,dword ptr [ebp-8]*/
1261 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ESI), -8);
1262 /* mov edi,dword ptr [ebp-4]*/
1263 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDI), -4);
1264
1265 EMIT1(0xC9); /* leave */
1266 EMIT1(0xC3); /* ret */
1267 *pprog = prog;
1268 }
1269
1270 /*
1271 * Generate the following code:
1272 * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
1273 * if (index >= array->map.max_entries)
1274 * goto out;
1275 * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
1276 * goto out;
1277 * prog = array->ptrs[index];
1278 * if (prog == NULL)
1279 * goto out;
1280 * goto *(prog->bpf_func + prologue_size);
1281 * out:
1282 */
emit_bpf_tail_call(u8 ** pprog)1283 static void emit_bpf_tail_call(u8 **pprog)
1284 {
1285 u8 *prog = *pprog;
1286 int cnt = 0;
1287 const u8 *r1 = bpf2ia32[BPF_REG_1];
1288 const u8 *r2 = bpf2ia32[BPF_REG_2];
1289 const u8 *r3 = bpf2ia32[BPF_REG_3];
1290 const u8 *tcc = bpf2ia32[TCALL_CNT];
1291 u32 lo, hi;
1292 static int jmp_label1 = -1;
1293
1294 /*
1295 * if (index >= array->map.max_entries)
1296 * goto out;
1297 */
1298 /* mov eax,dword ptr [ebp+off] */
1299 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r2[0]));
1300 /* mov edx,dword ptr [ebp+off] */
1301 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(r3[0]));
1302
1303 /* cmp dword ptr [eax+off],edx */
1304 EMIT3(0x39, add_2reg(0x40, IA32_EAX, IA32_EDX),
1305 offsetof(struct bpf_array, map.max_entries));
1306 /* jbe out */
1307 EMIT2(IA32_JBE, jmp_label(jmp_label1, 2));
1308
1309 /*
1310 * if (tail_call_cnt > MAX_TAIL_CALL_CNT)
1311 * goto out;
1312 */
1313 lo = (u32)MAX_TAIL_CALL_CNT;
1314 hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32);
1315 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(tcc[0]));
1316 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1317
1318 /* cmp edx,hi */
1319 EMIT3(0x83, add_1reg(0xF8, IA32_EBX), hi);
1320 EMIT2(IA32_JNE, 3);
1321 /* cmp ecx,lo */
1322 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), lo);
1323
1324 /* ja out */
1325 EMIT2(IA32_JAE, jmp_label(jmp_label1, 2));
1326
1327 /* add eax,0x1 */
1328 EMIT3(0x83, add_1reg(0xC0, IA32_ECX), 0x01);
1329 /* adc ebx,0x0 */
1330 EMIT3(0x83, add_1reg(0xD0, IA32_EBX), 0x00);
1331
1332 /* mov dword ptr [ebp+off],eax */
1333 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(tcc[0]));
1334 /* mov dword ptr [ebp+off],edx */
1335 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1336
1337 /* prog = array->ptrs[index]; */
1338 /* mov edx, [eax + edx * 4 + offsetof(...)] */
1339 EMIT3_off32(0x8B, 0x94, 0x90, offsetof(struct bpf_array, ptrs));
1340
1341 /*
1342 * if (prog == NULL)
1343 * goto out;
1344 */
1345 /* test edx,edx */
1346 EMIT2(0x85, add_2reg(0xC0, IA32_EDX, IA32_EDX));
1347 /* je out */
1348 EMIT2(IA32_JE, jmp_label(jmp_label1, 2));
1349
1350 /* goto *(prog->bpf_func + prologue_size); */
1351 /* mov edx, dword ptr [edx + 32] */
1352 EMIT3(0x8B, add_2reg(0x40, IA32_EDX, IA32_EDX),
1353 offsetof(struct bpf_prog, bpf_func));
1354 /* add edx,prologue_size */
1355 EMIT3(0x83, add_1reg(0xC0, IA32_EDX), PROLOGUE_SIZE);
1356
1357 /* mov eax,dword ptr [ebp+off] */
1358 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r1[0]));
1359
1360 /*
1361 * Now we're ready to jump into next BPF program:
1362 * eax == ctx (1st arg)
1363 * edx == prog->bpf_func + prologue_size
1364 */
1365 RETPOLINE_EDX_BPF_JIT();
1366
1367 if (jmp_label1 == -1)
1368 jmp_label1 = cnt;
1369
1370 /* out: */
1371 *pprog = prog;
1372 }
1373
1374 /* Push the scratch stack register on top of the stack. */
emit_push_r64(const u8 src[],u8 ** pprog)1375 static inline void emit_push_r64(const u8 src[], u8 **pprog)
1376 {
1377 u8 *prog = *pprog;
1378 int cnt = 0;
1379
1380 /* mov ecx,dword ptr [ebp+off] */
1381 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src_hi));
1382 /* push ecx */
1383 EMIT1(0x51);
1384
1385 /* mov ecx,dword ptr [ebp+off] */
1386 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src_lo));
1387 /* push ecx */
1388 EMIT1(0x51);
1389
1390 *pprog = prog;
1391 }
1392
get_cond_jmp_opcode(const u8 op,bool is_cmp_lo)1393 static u8 get_cond_jmp_opcode(const u8 op, bool is_cmp_lo)
1394 {
1395 u8 jmp_cond;
1396
1397 /* Convert BPF opcode to x86 */
1398 switch (op) {
1399 case BPF_JEQ:
1400 jmp_cond = IA32_JE;
1401 break;
1402 case BPF_JSET:
1403 case BPF_JNE:
1404 jmp_cond = IA32_JNE;
1405 break;
1406 case BPF_JGT:
1407 /* GT is unsigned '>', JA in x86 */
1408 jmp_cond = IA32_JA;
1409 break;
1410 case BPF_JLT:
1411 /* LT is unsigned '<', JB in x86 */
1412 jmp_cond = IA32_JB;
1413 break;
1414 case BPF_JGE:
1415 /* GE is unsigned '>=', JAE in x86 */
1416 jmp_cond = IA32_JAE;
1417 break;
1418 case BPF_JLE:
1419 /* LE is unsigned '<=', JBE in x86 */
1420 jmp_cond = IA32_JBE;
1421 break;
1422 case BPF_JSGT:
1423 if (!is_cmp_lo)
1424 /* Signed '>', GT in x86 */
1425 jmp_cond = IA32_JG;
1426 else
1427 /* GT is unsigned '>', JA in x86 */
1428 jmp_cond = IA32_JA;
1429 break;
1430 case BPF_JSLT:
1431 if (!is_cmp_lo)
1432 /* Signed '<', LT in x86 */
1433 jmp_cond = IA32_JL;
1434 else
1435 /* LT is unsigned '<', JB in x86 */
1436 jmp_cond = IA32_JB;
1437 break;
1438 case BPF_JSGE:
1439 if (!is_cmp_lo)
1440 /* Signed '>=', GE in x86 */
1441 jmp_cond = IA32_JGE;
1442 else
1443 /* GE is unsigned '>=', JAE in x86 */
1444 jmp_cond = IA32_JAE;
1445 break;
1446 case BPF_JSLE:
1447 if (!is_cmp_lo)
1448 /* Signed '<=', LE in x86 */
1449 jmp_cond = IA32_JLE;
1450 else
1451 /* LE is unsigned '<=', JBE in x86 */
1452 jmp_cond = IA32_JBE;
1453 break;
1454 default: /* to silence GCC warning */
1455 jmp_cond = COND_JMP_OPCODE_INVALID;
1456 break;
1457 }
1458
1459 return jmp_cond;
1460 }
1461
do_jit(struct bpf_prog * bpf_prog,int * addrs,u8 * image,int oldproglen,struct jit_context * ctx)1462 static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
1463 int oldproglen, struct jit_context *ctx)
1464 {
1465 struct bpf_insn *insn = bpf_prog->insnsi;
1466 int insn_cnt = bpf_prog->len;
1467 bool seen_exit = false;
1468 u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
1469 int i, cnt = 0;
1470 int proglen = 0;
1471 u8 *prog = temp;
1472
1473 emit_prologue(&prog, bpf_prog->aux->stack_depth);
1474
1475 for (i = 0; i < insn_cnt; i++, insn++) {
1476 const s32 imm32 = insn->imm;
1477 const bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
1478 const bool dstk = insn->dst_reg == BPF_REG_AX ? false : true;
1479 const bool sstk = insn->src_reg == BPF_REG_AX ? false : true;
1480 const u8 code = insn->code;
1481 const u8 *dst = bpf2ia32[insn->dst_reg];
1482 const u8 *src = bpf2ia32[insn->src_reg];
1483 const u8 *r0 = bpf2ia32[BPF_REG_0];
1484 s64 jmp_offset;
1485 u8 jmp_cond;
1486 int ilen;
1487 u8 *func;
1488
1489 switch (code) {
1490 /* ALU operations */
1491 /* dst = src */
1492 case BPF_ALU | BPF_MOV | BPF_K:
1493 case BPF_ALU | BPF_MOV | BPF_X:
1494 case BPF_ALU64 | BPF_MOV | BPF_K:
1495 case BPF_ALU64 | BPF_MOV | BPF_X:
1496 switch (BPF_SRC(code)) {
1497 case BPF_X:
1498 if (imm32 == 1) {
1499 /* Special mov32 for zext. */
1500 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1501 break;
1502 }
1503 emit_ia32_mov_r64(is64, dst, src, dstk, sstk,
1504 &prog, bpf_prog->aux);
1505 break;
1506 case BPF_K:
1507 /* Sign-extend immediate value to dst reg */
1508 emit_ia32_mov_i64(is64, dst, imm32,
1509 dstk, &prog);
1510 break;
1511 }
1512 break;
1513 /* dst = dst + src/imm */
1514 /* dst = dst - src/imm */
1515 /* dst = dst | src/imm */
1516 /* dst = dst & src/imm */
1517 /* dst = dst ^ src/imm */
1518 /* dst = dst * src/imm */
1519 /* dst = dst << src */
1520 /* dst = dst >> src */
1521 case BPF_ALU | BPF_ADD | BPF_K:
1522 case BPF_ALU | BPF_ADD | BPF_X:
1523 case BPF_ALU | BPF_SUB | BPF_K:
1524 case BPF_ALU | BPF_SUB | BPF_X:
1525 case BPF_ALU | BPF_OR | BPF_K:
1526 case BPF_ALU | BPF_OR | BPF_X:
1527 case BPF_ALU | BPF_AND | BPF_K:
1528 case BPF_ALU | BPF_AND | BPF_X:
1529 case BPF_ALU | BPF_XOR | BPF_K:
1530 case BPF_ALU | BPF_XOR | BPF_X:
1531 case BPF_ALU64 | BPF_ADD | BPF_K:
1532 case BPF_ALU64 | BPF_ADD | BPF_X:
1533 case BPF_ALU64 | BPF_SUB | BPF_K:
1534 case BPF_ALU64 | BPF_SUB | BPF_X:
1535 case BPF_ALU64 | BPF_OR | BPF_K:
1536 case BPF_ALU64 | BPF_OR | BPF_X:
1537 case BPF_ALU64 | BPF_AND | BPF_K:
1538 case BPF_ALU64 | BPF_AND | BPF_X:
1539 case BPF_ALU64 | BPF_XOR | BPF_K:
1540 case BPF_ALU64 | BPF_XOR | BPF_X:
1541 switch (BPF_SRC(code)) {
1542 case BPF_X:
1543 emit_ia32_alu_r64(is64, BPF_OP(code), dst,
1544 src, dstk, sstk, &prog,
1545 bpf_prog->aux);
1546 break;
1547 case BPF_K:
1548 emit_ia32_alu_i64(is64, BPF_OP(code), dst,
1549 imm32, dstk, &prog,
1550 bpf_prog->aux);
1551 break;
1552 }
1553 break;
1554 case BPF_ALU | BPF_MUL | BPF_K:
1555 case BPF_ALU | BPF_MUL | BPF_X:
1556 switch (BPF_SRC(code)) {
1557 case BPF_X:
1558 emit_ia32_mul_r(dst_lo, src_lo, dstk,
1559 sstk, &prog);
1560 break;
1561 case BPF_K:
1562 /* mov ecx,imm32*/
1563 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1564 imm32);
1565 emit_ia32_mul_r(dst_lo, IA32_ECX, dstk,
1566 false, &prog);
1567 break;
1568 }
1569 if (!bpf_prog->aux->verifier_zext)
1570 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1571 break;
1572 case BPF_ALU | BPF_LSH | BPF_X:
1573 case BPF_ALU | BPF_RSH | BPF_X:
1574 case BPF_ALU | BPF_ARSH | BPF_K:
1575 case BPF_ALU | BPF_ARSH | BPF_X:
1576 switch (BPF_SRC(code)) {
1577 case BPF_X:
1578 emit_ia32_shift_r(BPF_OP(code), dst_lo, src_lo,
1579 dstk, sstk, &prog);
1580 break;
1581 case BPF_K:
1582 /* mov ecx,imm32*/
1583 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1584 imm32);
1585 emit_ia32_shift_r(BPF_OP(code), dst_lo,
1586 IA32_ECX, dstk, false,
1587 &prog);
1588 break;
1589 }
1590 if (!bpf_prog->aux->verifier_zext)
1591 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1592 break;
1593 /* dst = dst / src(imm) */
1594 /* dst = dst % src(imm) */
1595 case BPF_ALU | BPF_DIV | BPF_K:
1596 case BPF_ALU | BPF_DIV | BPF_X:
1597 case BPF_ALU | BPF_MOD | BPF_K:
1598 case BPF_ALU | BPF_MOD | BPF_X:
1599 switch (BPF_SRC(code)) {
1600 case BPF_X:
1601 emit_ia32_div_mod_r(BPF_OP(code), dst_lo,
1602 src_lo, dstk, sstk, &prog);
1603 break;
1604 case BPF_K:
1605 /* mov ecx,imm32*/
1606 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1607 imm32);
1608 emit_ia32_div_mod_r(BPF_OP(code), dst_lo,
1609 IA32_ECX, dstk, false,
1610 &prog);
1611 break;
1612 }
1613 if (!bpf_prog->aux->verifier_zext)
1614 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1615 break;
1616 case BPF_ALU64 | BPF_DIV | BPF_K:
1617 case BPF_ALU64 | BPF_DIV | BPF_X:
1618 case BPF_ALU64 | BPF_MOD | BPF_K:
1619 case BPF_ALU64 | BPF_MOD | BPF_X:
1620 goto notyet;
1621 /* dst = dst >> imm */
1622 /* dst = dst << imm */
1623 case BPF_ALU | BPF_RSH | BPF_K:
1624 case BPF_ALU | BPF_LSH | BPF_K:
1625 if (unlikely(imm32 > 31))
1626 return -EINVAL;
1627 /* mov ecx,imm32*/
1628 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
1629 emit_ia32_shift_r(BPF_OP(code), dst_lo, IA32_ECX, dstk,
1630 false, &prog);
1631 if (!bpf_prog->aux->verifier_zext)
1632 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1633 break;
1634 /* dst = dst << imm */
1635 case BPF_ALU64 | BPF_LSH | BPF_K:
1636 if (unlikely(imm32 > 63))
1637 return -EINVAL;
1638 emit_ia32_lsh_i64(dst, imm32, dstk, &prog);
1639 break;
1640 /* dst = dst >> imm */
1641 case BPF_ALU64 | BPF_RSH | BPF_K:
1642 if (unlikely(imm32 > 63))
1643 return -EINVAL;
1644 emit_ia32_rsh_i64(dst, imm32, dstk, &prog);
1645 break;
1646 /* dst = dst << src */
1647 case BPF_ALU64 | BPF_LSH | BPF_X:
1648 emit_ia32_lsh_r64(dst, src, dstk, sstk, &prog);
1649 break;
1650 /* dst = dst >> src */
1651 case BPF_ALU64 | BPF_RSH | BPF_X:
1652 emit_ia32_rsh_r64(dst, src, dstk, sstk, &prog);
1653 break;
1654 /* dst = dst >> src (signed) */
1655 case BPF_ALU64 | BPF_ARSH | BPF_X:
1656 emit_ia32_arsh_r64(dst, src, dstk, sstk, &prog);
1657 break;
1658 /* dst = dst >> imm (signed) */
1659 case BPF_ALU64 | BPF_ARSH | BPF_K:
1660 if (unlikely(imm32 > 63))
1661 return -EINVAL;
1662 emit_ia32_arsh_i64(dst, imm32, dstk, &prog);
1663 break;
1664 /* dst = ~dst */
1665 case BPF_ALU | BPF_NEG:
1666 emit_ia32_alu_i(is64, false, BPF_OP(code),
1667 dst_lo, 0, dstk, &prog);
1668 if (!bpf_prog->aux->verifier_zext)
1669 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1670 break;
1671 /* dst = ~dst (64 bit) */
1672 case BPF_ALU64 | BPF_NEG:
1673 emit_ia32_neg64(dst, dstk, &prog);
1674 break;
1675 /* dst = dst * src/imm */
1676 case BPF_ALU64 | BPF_MUL | BPF_X:
1677 case BPF_ALU64 | BPF_MUL | BPF_K:
1678 switch (BPF_SRC(code)) {
1679 case BPF_X:
1680 emit_ia32_mul_r64(dst, src, dstk, sstk, &prog);
1681 break;
1682 case BPF_K:
1683 emit_ia32_mul_i64(dst, imm32, dstk, &prog);
1684 break;
1685 }
1686 break;
1687 /* dst = htole(dst) */
1688 case BPF_ALU | BPF_END | BPF_FROM_LE:
1689 emit_ia32_to_le_r64(dst, imm32, dstk, &prog,
1690 bpf_prog->aux);
1691 break;
1692 /* dst = htobe(dst) */
1693 case BPF_ALU | BPF_END | BPF_FROM_BE:
1694 emit_ia32_to_be_r64(dst, imm32, dstk, &prog,
1695 bpf_prog->aux);
1696 break;
1697 /* dst = imm64 */
1698 case BPF_LD | BPF_IMM | BPF_DW: {
1699 s32 hi, lo = imm32;
1700
1701 hi = insn[1].imm;
1702 emit_ia32_mov_i(dst_lo, lo, dstk, &prog);
1703 emit_ia32_mov_i(dst_hi, hi, dstk, &prog);
1704 insn++;
1705 i++;
1706 break;
1707 }
1708 /* speculation barrier */
1709 case BPF_ST | BPF_NOSPEC:
1710 if (boot_cpu_has(X86_FEATURE_XMM2))
1711 /* Emit 'lfence' */
1712 EMIT3(0x0F, 0xAE, 0xE8);
1713 break;
1714 /* ST: *(u8*)(dst_reg + off) = imm */
1715 case BPF_ST | BPF_MEM | BPF_H:
1716 case BPF_ST | BPF_MEM | BPF_B:
1717 case BPF_ST | BPF_MEM | BPF_W:
1718 case BPF_ST | BPF_MEM | BPF_DW:
1719 if (dstk)
1720 /* mov eax,dword ptr [ebp+off] */
1721 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1722 STACK_VAR(dst_lo));
1723 else
1724 /* mov eax,dst_lo */
1725 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1726
1727 switch (BPF_SIZE(code)) {
1728 case BPF_B:
1729 EMIT(0xC6, 1); break;
1730 case BPF_H:
1731 EMIT2(0x66, 0xC7); break;
1732 case BPF_W:
1733 case BPF_DW:
1734 EMIT(0xC7, 1); break;
1735 }
1736
1737 if (is_imm8(insn->off))
1738 EMIT2(add_1reg(0x40, IA32_EAX), insn->off);
1739 else
1740 EMIT1_off32(add_1reg(0x80, IA32_EAX),
1741 insn->off);
1742 EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(code)));
1743
1744 if (BPF_SIZE(code) == BPF_DW) {
1745 u32 hi;
1746
1747 hi = imm32 & (1<<31) ? (u32)~0 : 0;
1748 EMIT2_off32(0xC7, add_1reg(0x80, IA32_EAX),
1749 insn->off + 4);
1750 EMIT(hi, 4);
1751 }
1752 break;
1753
1754 /* STX: *(u8*)(dst_reg + off) = src_reg */
1755 case BPF_STX | BPF_MEM | BPF_B:
1756 case BPF_STX | BPF_MEM | BPF_H:
1757 case BPF_STX | BPF_MEM | BPF_W:
1758 case BPF_STX | BPF_MEM | BPF_DW:
1759 if (dstk)
1760 /* mov eax,dword ptr [ebp+off] */
1761 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1762 STACK_VAR(dst_lo));
1763 else
1764 /* mov eax,dst_lo */
1765 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1766
1767 if (sstk)
1768 /* mov edx,dword ptr [ebp+off] */
1769 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
1770 STACK_VAR(src_lo));
1771 else
1772 /* mov edx,src_lo */
1773 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_EDX));
1774
1775 switch (BPF_SIZE(code)) {
1776 case BPF_B:
1777 EMIT(0x88, 1); break;
1778 case BPF_H:
1779 EMIT2(0x66, 0x89); break;
1780 case BPF_W:
1781 case BPF_DW:
1782 EMIT(0x89, 1); break;
1783 }
1784
1785 if (is_imm8(insn->off))
1786 EMIT2(add_2reg(0x40, IA32_EAX, IA32_EDX),
1787 insn->off);
1788 else
1789 EMIT1_off32(add_2reg(0x80, IA32_EAX, IA32_EDX),
1790 insn->off);
1791
1792 if (BPF_SIZE(code) == BPF_DW) {
1793 if (sstk)
1794 /* mov edi,dword ptr [ebp+off] */
1795 EMIT3(0x8B, add_2reg(0x40, IA32_EBP,
1796 IA32_EDX),
1797 STACK_VAR(src_hi));
1798 else
1799 /* mov edi,src_hi */
1800 EMIT2(0x8B, add_2reg(0xC0, src_hi,
1801 IA32_EDX));
1802 EMIT1(0x89);
1803 if (is_imm8(insn->off + 4)) {
1804 EMIT2(add_2reg(0x40, IA32_EAX,
1805 IA32_EDX),
1806 insn->off + 4);
1807 } else {
1808 EMIT1(add_2reg(0x80, IA32_EAX,
1809 IA32_EDX));
1810 EMIT(insn->off + 4, 4);
1811 }
1812 }
1813 break;
1814
1815 /* LDX: dst_reg = *(u8*)(src_reg + off) */
1816 case BPF_LDX | BPF_MEM | BPF_B:
1817 case BPF_LDX | BPF_MEM | BPF_H:
1818 case BPF_LDX | BPF_MEM | BPF_W:
1819 case BPF_LDX | BPF_MEM | BPF_DW:
1820 if (sstk)
1821 /* mov eax,dword ptr [ebp+off] */
1822 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1823 STACK_VAR(src_lo));
1824 else
1825 /* mov eax,dword ptr [ebp+off] */
1826 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_EAX));
1827
1828 switch (BPF_SIZE(code)) {
1829 case BPF_B:
1830 EMIT2(0x0F, 0xB6); break;
1831 case BPF_H:
1832 EMIT2(0x0F, 0xB7); break;
1833 case BPF_W:
1834 case BPF_DW:
1835 EMIT(0x8B, 1); break;
1836 }
1837
1838 if (is_imm8(insn->off))
1839 EMIT2(add_2reg(0x40, IA32_EAX, IA32_EDX),
1840 insn->off);
1841 else
1842 EMIT1_off32(add_2reg(0x80, IA32_EAX, IA32_EDX),
1843 insn->off);
1844
1845 if (dstk)
1846 /* mov dword ptr [ebp+off],edx */
1847 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
1848 STACK_VAR(dst_lo));
1849 else
1850 /* mov dst_lo,edx */
1851 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EDX));
1852 switch (BPF_SIZE(code)) {
1853 case BPF_B:
1854 case BPF_H:
1855 case BPF_W:
1856 if (bpf_prog->aux->verifier_zext)
1857 break;
1858 if (dstk) {
1859 EMIT3(0xC7, add_1reg(0x40, IA32_EBP),
1860 STACK_VAR(dst_hi));
1861 EMIT(0x0, 4);
1862 } else {
1863 /* xor dst_hi,dst_hi */
1864 EMIT2(0x33,
1865 add_2reg(0xC0, dst_hi, dst_hi));
1866 }
1867 break;
1868 case BPF_DW:
1869 EMIT2_off32(0x8B,
1870 add_2reg(0x80, IA32_EAX, IA32_EDX),
1871 insn->off + 4);
1872 if (dstk)
1873 EMIT3(0x89,
1874 add_2reg(0x40, IA32_EBP,
1875 IA32_EDX),
1876 STACK_VAR(dst_hi));
1877 else
1878 EMIT2(0x89,
1879 add_2reg(0xC0, dst_hi, IA32_EDX));
1880 break;
1881 default:
1882 break;
1883 }
1884 break;
1885 /* call */
1886 case BPF_JMP | BPF_CALL:
1887 {
1888 const u8 *r1 = bpf2ia32[BPF_REG_1];
1889 const u8 *r2 = bpf2ia32[BPF_REG_2];
1890 const u8 *r3 = bpf2ia32[BPF_REG_3];
1891 const u8 *r4 = bpf2ia32[BPF_REG_4];
1892 const u8 *r5 = bpf2ia32[BPF_REG_5];
1893
1894 if (insn->src_reg == BPF_PSEUDO_CALL)
1895 goto notyet;
1896
1897 func = (u8 *) __bpf_call_base + imm32;
1898 jmp_offset = func - (image + addrs[i]);
1899
1900 if (!imm32 || !is_simm32(jmp_offset)) {
1901 pr_err("unsupported BPF func %d addr %p image %p\n",
1902 imm32, func, image);
1903 return -EINVAL;
1904 }
1905
1906 /* mov eax,dword ptr [ebp+off] */
1907 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1908 STACK_VAR(r1[0]));
1909 /* mov edx,dword ptr [ebp+off] */
1910 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
1911 STACK_VAR(r1[1]));
1912
1913 emit_push_r64(r5, &prog);
1914 emit_push_r64(r4, &prog);
1915 emit_push_r64(r3, &prog);
1916 emit_push_r64(r2, &prog);
1917
1918 EMIT1_off32(0xE8, jmp_offset + 9);
1919
1920 /* mov dword ptr [ebp+off],eax */
1921 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1922 STACK_VAR(r0[0]));
1923 /* mov dword ptr [ebp+off],edx */
1924 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
1925 STACK_VAR(r0[1]));
1926
1927 /* add esp,32 */
1928 EMIT3(0x83, add_1reg(0xC0, IA32_ESP), 32);
1929 break;
1930 }
1931 case BPF_JMP | BPF_TAIL_CALL:
1932 emit_bpf_tail_call(&prog);
1933 break;
1934
1935 /* cond jump */
1936 case BPF_JMP | BPF_JEQ | BPF_X:
1937 case BPF_JMP | BPF_JNE | BPF_X:
1938 case BPF_JMP | BPF_JGT | BPF_X:
1939 case BPF_JMP | BPF_JLT | BPF_X:
1940 case BPF_JMP | BPF_JGE | BPF_X:
1941 case BPF_JMP | BPF_JLE | BPF_X:
1942 case BPF_JMP32 | BPF_JEQ | BPF_X:
1943 case BPF_JMP32 | BPF_JNE | BPF_X:
1944 case BPF_JMP32 | BPF_JGT | BPF_X:
1945 case BPF_JMP32 | BPF_JLT | BPF_X:
1946 case BPF_JMP32 | BPF_JGE | BPF_X:
1947 case BPF_JMP32 | BPF_JLE | BPF_X:
1948 case BPF_JMP32 | BPF_JSGT | BPF_X:
1949 case BPF_JMP32 | BPF_JSLE | BPF_X:
1950 case BPF_JMP32 | BPF_JSLT | BPF_X:
1951 case BPF_JMP32 | BPF_JSGE | BPF_X: {
1952 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
1953 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
1954 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
1955 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
1956 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
1957
1958 if (dstk) {
1959 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1960 STACK_VAR(dst_lo));
1961 if (is_jmp64)
1962 EMIT3(0x8B,
1963 add_2reg(0x40, IA32_EBP,
1964 IA32_EDX),
1965 STACK_VAR(dst_hi));
1966 }
1967
1968 if (sstk) {
1969 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
1970 STACK_VAR(src_lo));
1971 if (is_jmp64)
1972 EMIT3(0x8B,
1973 add_2reg(0x40, IA32_EBP,
1974 IA32_EBX),
1975 STACK_VAR(src_hi));
1976 }
1977
1978 if (is_jmp64) {
1979 /* cmp dreg_hi,sreg_hi */
1980 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
1981 EMIT2(IA32_JNE, 2);
1982 }
1983 /* cmp dreg_lo,sreg_lo */
1984 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
1985 goto emit_cond_jmp;
1986 }
1987 case BPF_JMP | BPF_JSGT | BPF_X:
1988 case BPF_JMP | BPF_JSLE | BPF_X:
1989 case BPF_JMP | BPF_JSLT | BPF_X:
1990 case BPF_JMP | BPF_JSGE | BPF_X: {
1991 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
1992 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
1993 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
1994 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
1995
1996 if (dstk) {
1997 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1998 STACK_VAR(dst_lo));
1999 EMIT3(0x8B,
2000 add_2reg(0x40, IA32_EBP,
2001 IA32_EDX),
2002 STACK_VAR(dst_hi));
2003 }
2004
2005 if (sstk) {
2006 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
2007 STACK_VAR(src_lo));
2008 EMIT3(0x8B,
2009 add_2reg(0x40, IA32_EBP,
2010 IA32_EBX),
2011 STACK_VAR(src_hi));
2012 }
2013
2014 /* cmp dreg_hi,sreg_hi */
2015 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2016 EMIT2(IA32_JNE, 10);
2017 /* cmp dreg_lo,sreg_lo */
2018 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2019 goto emit_cond_jmp_signed;
2020 }
2021 case BPF_JMP | BPF_JSET | BPF_X:
2022 case BPF_JMP32 | BPF_JSET | BPF_X: {
2023 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2024 u8 dreg_lo = IA32_EAX;
2025 u8 dreg_hi = IA32_EDX;
2026 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
2027 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
2028
2029 if (dstk) {
2030 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2031 STACK_VAR(dst_lo));
2032 if (is_jmp64)
2033 EMIT3(0x8B,
2034 add_2reg(0x40, IA32_EBP,
2035 IA32_EDX),
2036 STACK_VAR(dst_hi));
2037 } else {
2038 /* mov dreg_lo,dst_lo */
2039 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dst_lo));
2040 if (is_jmp64)
2041 /* mov dreg_hi,dst_hi */
2042 EMIT2(0x89,
2043 add_2reg(0xC0, dreg_hi, dst_hi));
2044 }
2045
2046 if (sstk) {
2047 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
2048 STACK_VAR(src_lo));
2049 if (is_jmp64)
2050 EMIT3(0x8B,
2051 add_2reg(0x40, IA32_EBP,
2052 IA32_EBX),
2053 STACK_VAR(src_hi));
2054 }
2055 /* and dreg_lo,sreg_lo */
2056 EMIT2(0x23, add_2reg(0xC0, sreg_lo, dreg_lo));
2057 if (is_jmp64) {
2058 /* and dreg_hi,sreg_hi */
2059 EMIT2(0x23, add_2reg(0xC0, sreg_hi, dreg_hi));
2060 /* or dreg_lo,dreg_hi */
2061 EMIT2(0x09, add_2reg(0xC0, dreg_lo, dreg_hi));
2062 }
2063 goto emit_cond_jmp;
2064 }
2065 case BPF_JMP | BPF_JSET | BPF_K:
2066 case BPF_JMP32 | BPF_JSET | BPF_K: {
2067 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2068 u8 dreg_lo = IA32_EAX;
2069 u8 dreg_hi = IA32_EDX;
2070 u8 sreg_lo = IA32_ECX;
2071 u8 sreg_hi = IA32_EBX;
2072 u32 hi;
2073
2074 if (dstk) {
2075 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2076 STACK_VAR(dst_lo));
2077 if (is_jmp64)
2078 EMIT3(0x8B,
2079 add_2reg(0x40, IA32_EBP,
2080 IA32_EDX),
2081 STACK_VAR(dst_hi));
2082 } else {
2083 /* mov dreg_lo,dst_lo */
2084 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dst_lo));
2085 if (is_jmp64)
2086 /* mov dreg_hi,dst_hi */
2087 EMIT2(0x89,
2088 add_2reg(0xC0, dreg_hi, dst_hi));
2089 }
2090
2091 /* mov ecx,imm32 */
2092 EMIT2_off32(0xC7, add_1reg(0xC0, sreg_lo), imm32);
2093
2094 /* and dreg_lo,sreg_lo */
2095 EMIT2(0x23, add_2reg(0xC0, sreg_lo, dreg_lo));
2096 if (is_jmp64) {
2097 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2098 /* mov ebx,imm32 */
2099 EMIT2_off32(0xC7, add_1reg(0xC0, sreg_hi), hi);
2100 /* and dreg_hi,sreg_hi */
2101 EMIT2(0x23, add_2reg(0xC0, sreg_hi, dreg_hi));
2102 /* or dreg_lo,dreg_hi */
2103 EMIT2(0x09, add_2reg(0xC0, dreg_lo, dreg_hi));
2104 }
2105 goto emit_cond_jmp;
2106 }
2107 case BPF_JMP | BPF_JEQ | BPF_K:
2108 case BPF_JMP | BPF_JNE | BPF_K:
2109 case BPF_JMP | BPF_JGT | BPF_K:
2110 case BPF_JMP | BPF_JLT | BPF_K:
2111 case BPF_JMP | BPF_JGE | BPF_K:
2112 case BPF_JMP | BPF_JLE | BPF_K:
2113 case BPF_JMP32 | BPF_JEQ | BPF_K:
2114 case BPF_JMP32 | BPF_JNE | BPF_K:
2115 case BPF_JMP32 | BPF_JGT | BPF_K:
2116 case BPF_JMP32 | BPF_JLT | BPF_K:
2117 case BPF_JMP32 | BPF_JGE | BPF_K:
2118 case BPF_JMP32 | BPF_JLE | BPF_K:
2119 case BPF_JMP32 | BPF_JSGT | BPF_K:
2120 case BPF_JMP32 | BPF_JSLE | BPF_K:
2121 case BPF_JMP32 | BPF_JSLT | BPF_K:
2122 case BPF_JMP32 | BPF_JSGE | BPF_K: {
2123 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2124 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2125 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2126 u8 sreg_lo = IA32_ECX;
2127 u8 sreg_hi = IA32_EBX;
2128 u32 hi;
2129
2130 if (dstk) {
2131 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2132 STACK_VAR(dst_lo));
2133 if (is_jmp64)
2134 EMIT3(0x8B,
2135 add_2reg(0x40, IA32_EBP,
2136 IA32_EDX),
2137 STACK_VAR(dst_hi));
2138 }
2139
2140 /* mov ecx,imm32 */
2141 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
2142 if (is_jmp64) {
2143 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2144 /* mov ebx,imm32 */
2145 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EBX), hi);
2146 /* cmp dreg_hi,sreg_hi */
2147 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2148 EMIT2(IA32_JNE, 2);
2149 }
2150 /* cmp dreg_lo,sreg_lo */
2151 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2152
2153 emit_cond_jmp: jmp_cond = get_cond_jmp_opcode(BPF_OP(code), false);
2154 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2155 return -EFAULT;
2156 jmp_offset = addrs[i + insn->off] - addrs[i];
2157 if (is_imm8(jmp_offset)) {
2158 EMIT2(jmp_cond, jmp_offset);
2159 } else if (is_simm32(jmp_offset)) {
2160 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2161 } else {
2162 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2163 return -EFAULT;
2164 }
2165 break;
2166 }
2167 case BPF_JMP | BPF_JSGT | BPF_K:
2168 case BPF_JMP | BPF_JSLE | BPF_K:
2169 case BPF_JMP | BPF_JSLT | BPF_K:
2170 case BPF_JMP | BPF_JSGE | BPF_K: {
2171 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2172 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2173 u8 sreg_lo = IA32_ECX;
2174 u8 sreg_hi = IA32_EBX;
2175 u32 hi;
2176
2177 if (dstk) {
2178 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2179 STACK_VAR(dst_lo));
2180 EMIT3(0x8B,
2181 add_2reg(0x40, IA32_EBP,
2182 IA32_EDX),
2183 STACK_VAR(dst_hi));
2184 }
2185
2186 /* mov ecx,imm32 */
2187 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
2188 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2189 /* mov ebx,imm32 */
2190 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EBX), hi);
2191 /* cmp dreg_hi,sreg_hi */
2192 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2193 EMIT2(IA32_JNE, 10);
2194 /* cmp dreg_lo,sreg_lo */
2195 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2196
2197 /*
2198 * For simplicity of branch offset computation,
2199 * let's use fixed jump coding here.
2200 */
2201 emit_cond_jmp_signed: /* Check the condition for low 32-bit comparison */
2202 jmp_cond = get_cond_jmp_opcode(BPF_OP(code), true);
2203 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2204 return -EFAULT;
2205 jmp_offset = addrs[i + insn->off] - addrs[i] + 8;
2206 if (is_simm32(jmp_offset)) {
2207 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2208 } else {
2209 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2210 return -EFAULT;
2211 }
2212 EMIT2(0xEB, 6);
2213
2214 /* Check the condition for high 32-bit comparison */
2215 jmp_cond = get_cond_jmp_opcode(BPF_OP(code), false);
2216 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2217 return -EFAULT;
2218 jmp_offset = addrs[i + insn->off] - addrs[i];
2219 if (is_simm32(jmp_offset)) {
2220 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2221 } else {
2222 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2223 return -EFAULT;
2224 }
2225 break;
2226 }
2227 case BPF_JMP | BPF_JA:
2228 if (insn->off == -1)
2229 /* -1 jmp instructions will always jump
2230 * backwards two bytes. Explicitly handling
2231 * this case avoids wasting too many passes
2232 * when there are long sequences of replaced
2233 * dead code.
2234 */
2235 jmp_offset = -2;
2236 else
2237 jmp_offset = addrs[i + insn->off] - addrs[i];
2238
2239 if (!jmp_offset)
2240 /* Optimize out nop jumps */
2241 break;
2242 emit_jmp:
2243 if (is_imm8(jmp_offset)) {
2244 EMIT2(0xEB, jmp_offset);
2245 } else if (is_simm32(jmp_offset)) {
2246 EMIT1_off32(0xE9, jmp_offset);
2247 } else {
2248 pr_err("jmp gen bug %llx\n", jmp_offset);
2249 return -EFAULT;
2250 }
2251 break;
2252 /* STX XADD: lock *(u32 *)(dst + off) += src */
2253 case BPF_STX | BPF_XADD | BPF_W:
2254 /* STX XADD: lock *(u64 *)(dst + off) += src */
2255 case BPF_STX | BPF_XADD | BPF_DW:
2256 goto notyet;
2257 case BPF_JMP | BPF_EXIT:
2258 if (seen_exit) {
2259 jmp_offset = ctx->cleanup_addr - addrs[i];
2260 goto emit_jmp;
2261 }
2262 seen_exit = true;
2263 /* Update cleanup_addr */
2264 ctx->cleanup_addr = proglen;
2265 emit_epilogue(&prog, bpf_prog->aux->stack_depth);
2266 break;
2267 notyet:
2268 pr_info_once("*** NOT YET: opcode %02x ***\n", code);
2269 return -EFAULT;
2270 default:
2271 /*
2272 * This error will be seen if new instruction was added
2273 * to interpreter, but not to JIT or if there is junk in
2274 * bpf_prog
2275 */
2276 pr_err("bpf_jit: unknown opcode %02x\n", code);
2277 return -EINVAL;
2278 }
2279
2280 ilen = prog - temp;
2281 if (ilen > BPF_MAX_INSN_SIZE) {
2282 pr_err("bpf_jit: fatal insn size error\n");
2283 return -EFAULT;
2284 }
2285
2286 if (image) {
2287 /*
2288 * When populating the image, assert that:
2289 *
2290 * i) We do not write beyond the allocated space, and
2291 * ii) addrs[i] did not change from the prior run, in order
2292 * to validate assumptions made for computing branch
2293 * displacements.
2294 */
2295 if (unlikely(proglen + ilen > oldproglen ||
2296 proglen + ilen != addrs[i])) {
2297 pr_err("bpf_jit: fatal error\n");
2298 return -EFAULT;
2299 }
2300 memcpy(image + proglen, temp, ilen);
2301 }
2302 proglen += ilen;
2303 addrs[i] = proglen;
2304 prog = temp;
2305 }
2306 return proglen;
2307 }
2308
bpf_jit_needs_zext(void)2309 bool bpf_jit_needs_zext(void)
2310 {
2311 return true;
2312 }
2313
bpf_int_jit_compile(struct bpf_prog * prog)2314 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
2315 {
2316 struct bpf_binary_header *header = NULL;
2317 struct bpf_prog *tmp, *orig_prog = prog;
2318 int proglen, oldproglen = 0;
2319 struct jit_context ctx = {};
2320 bool tmp_blinded = false;
2321 u8 *image = NULL;
2322 int *addrs;
2323 int pass;
2324 int i;
2325
2326 if (!prog->jit_requested)
2327 return orig_prog;
2328
2329 tmp = bpf_jit_blind_constants(prog);
2330 /*
2331 * If blinding was requested and we failed during blinding,
2332 * we must fall back to the interpreter.
2333 */
2334 if (IS_ERR(tmp))
2335 return orig_prog;
2336 if (tmp != prog) {
2337 tmp_blinded = true;
2338 prog = tmp;
2339 }
2340
2341 addrs = kmalloc_array(prog->len, sizeof(*addrs), GFP_KERNEL);
2342 if (!addrs) {
2343 prog = orig_prog;
2344 goto out;
2345 }
2346
2347 /*
2348 * Before first pass, make a rough estimation of addrs[]
2349 * each BPF instruction is translated to less than 64 bytes
2350 */
2351 for (proglen = 0, i = 0; i < prog->len; i++) {
2352 proglen += 64;
2353 addrs[i] = proglen;
2354 }
2355 ctx.cleanup_addr = proglen;
2356
2357 /*
2358 * JITed image shrinks with every pass and the loop iterates
2359 * until the image stops shrinking. Very large BPF programs
2360 * may converge on the last pass. In such case do one more
2361 * pass to emit the final image.
2362 */
2363 for (pass = 0; pass < 20 || image; pass++) {
2364 proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
2365 if (proglen <= 0) {
2366 out_image:
2367 image = NULL;
2368 if (header)
2369 bpf_jit_binary_free(header);
2370 prog = orig_prog;
2371 goto out_addrs;
2372 }
2373 if (image) {
2374 if (proglen != oldproglen) {
2375 pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
2376 proglen, oldproglen);
2377 goto out_image;
2378 }
2379 break;
2380 }
2381 if (proglen == oldproglen) {
2382 header = bpf_jit_binary_alloc(proglen, &image,
2383 1, jit_fill_hole);
2384 if (!header) {
2385 prog = orig_prog;
2386 goto out_addrs;
2387 }
2388 }
2389 oldproglen = proglen;
2390 cond_resched();
2391 }
2392
2393 if (bpf_jit_enable > 1)
2394 bpf_jit_dump(prog->len, proglen, pass + 1, image);
2395
2396 if (image) {
2397 bpf_jit_binary_lock_ro(header);
2398 prog->bpf_func = (void *)image;
2399 prog->jited = 1;
2400 prog->jited_len = proglen;
2401 } else {
2402 prog = orig_prog;
2403 }
2404
2405 out_addrs:
2406 kfree(addrs);
2407 out:
2408 if (tmp_blinded)
2409 bpf_jit_prog_release_other(prog, prog == orig_prog ?
2410 tmp : orig_prog);
2411 return prog;
2412 }
2413