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 <asm/asm-prototypes.h>
19 #include <linux/bpf.h>
20
21 /*
22 * eBPF prog stack layout:
23 *
24 * high
25 * original ESP => +-----+
26 * | | callee saved registers
27 * +-----+
28 * | ... | eBPF JIT scratch space
29 * BPF_FP,IA32_EBP => +-----+
30 * | ... | eBPF prog stack
31 * +-----+
32 * |RSVD | JIT scratchpad
33 * current ESP => +-----+
34 * | |
35 * | ... | Function call stack
36 * | |
37 * +-----+
38 * low
39 *
40 * The callee saved registers:
41 *
42 * high
43 * original ESP => +------------------+ \
44 * | ebp | |
45 * current EBP => +------------------+ } callee saved registers
46 * | ebx,esi,edi | |
47 * +------------------+ /
48 * low
49 */
50
emit_code(u8 * ptr,u32 bytes,unsigned int len)51 static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
52 {
53 if (len == 1)
54 *ptr = bytes;
55 else if (len == 2)
56 *(u16 *)ptr = bytes;
57 else {
58 *(u32 *)ptr = bytes;
59 barrier();
60 }
61 return ptr + len;
62 }
63
64 #define EMIT(bytes, len) \
65 do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
66
67 #define EMIT1(b1) EMIT(b1, 1)
68 #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
69 #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
70 #define EMIT4(b1, b2, b3, b4) \
71 EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
72
73 #define EMIT1_off32(b1, off) \
74 do { EMIT1(b1); EMIT(off, 4); } while (0)
75 #define EMIT2_off32(b1, b2, off) \
76 do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
77 #define EMIT3_off32(b1, b2, b3, off) \
78 do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
79 #define EMIT4_off32(b1, b2, b3, b4, off) \
80 do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
81
82 #define jmp_label(label, jmp_insn_len) (label - cnt - jmp_insn_len)
83
is_imm8(int value)84 static bool is_imm8(int value)
85 {
86 return value <= 127 && value >= -128;
87 }
88
is_simm32(s64 value)89 static bool is_simm32(s64 value)
90 {
91 return value == (s64) (s32) value;
92 }
93
94 #define STACK_OFFSET(k) (k)
95 #define TCALL_CNT (MAX_BPF_JIT_REG + 0) /* Tail Call Count */
96
97 #define IA32_EAX (0x0)
98 #define IA32_EBX (0x3)
99 #define IA32_ECX (0x1)
100 #define IA32_EDX (0x2)
101 #define IA32_ESI (0x6)
102 #define IA32_EDI (0x7)
103 #define IA32_EBP (0x5)
104 #define IA32_ESP (0x4)
105
106 /*
107 * List of x86 cond jumps opcodes (. + s8)
108 * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
109 */
110 #define IA32_JB 0x72
111 #define IA32_JAE 0x73
112 #define IA32_JE 0x74
113 #define IA32_JNE 0x75
114 #define IA32_JBE 0x76
115 #define IA32_JA 0x77
116 #define IA32_JL 0x7C
117 #define IA32_JGE 0x7D
118 #define IA32_JLE 0x7E
119 #define IA32_JG 0x7F
120
121 #define COND_JMP_OPCODE_INVALID (0xFF)
122
123 /*
124 * Map eBPF registers to IA32 32bit registers or stack scratch space.
125 *
126 * 1. All the registers, R0-R10, are mapped to scratch space on stack.
127 * 2. We need two 64 bit temp registers to do complex operations on eBPF
128 * registers.
129 * 3. For performance reason, the BPF_REG_AX for blinding constant, is
130 * mapped to real hardware register pair, IA32_ESI and IA32_EDI.
131 *
132 * As the eBPF registers are all 64 bit registers and IA32 has only 32 bit
133 * registers, we have to map each eBPF registers with two IA32 32 bit regs
134 * or scratch memory space and we have to build eBPF 64 bit register from those.
135 *
136 * We use IA32_EAX, IA32_EDX, IA32_ECX, IA32_EBX as temporary registers.
137 */
138 static const u8 bpf2ia32[][2] = {
139 /* Return value from in-kernel function, and exit value from eBPF */
140 [BPF_REG_0] = {STACK_OFFSET(0), STACK_OFFSET(4)},
141
142 /* The arguments from eBPF program to in-kernel function */
143 /* Stored on stack scratch space */
144 [BPF_REG_1] = {STACK_OFFSET(8), STACK_OFFSET(12)},
145 [BPF_REG_2] = {STACK_OFFSET(16), STACK_OFFSET(20)},
146 [BPF_REG_3] = {STACK_OFFSET(24), STACK_OFFSET(28)},
147 [BPF_REG_4] = {STACK_OFFSET(32), STACK_OFFSET(36)},
148 [BPF_REG_5] = {STACK_OFFSET(40), STACK_OFFSET(44)},
149
150 /* Callee saved registers that in-kernel function will preserve */
151 /* Stored on stack scratch space */
152 [BPF_REG_6] = {STACK_OFFSET(48), STACK_OFFSET(52)},
153 [BPF_REG_7] = {STACK_OFFSET(56), STACK_OFFSET(60)},
154 [BPF_REG_8] = {STACK_OFFSET(64), STACK_OFFSET(68)},
155 [BPF_REG_9] = {STACK_OFFSET(72), STACK_OFFSET(76)},
156
157 /* Read only Frame Pointer to access Stack */
158 [BPF_REG_FP] = {STACK_OFFSET(80), STACK_OFFSET(84)},
159
160 /* Temporary register for blinding constants. */
161 [BPF_REG_AX] = {IA32_ESI, IA32_EDI},
162
163 /* Tail call count. Stored on stack scratch space. */
164 [TCALL_CNT] = {STACK_OFFSET(88), STACK_OFFSET(92)},
165 };
166
167 #define dst_lo dst[0]
168 #define dst_hi dst[1]
169 #define src_lo src[0]
170 #define src_hi src[1]
171
172 #define STACK_ALIGNMENT 8
173 /*
174 * Stack space for BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4,
175 * BPF_REG_5, BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9,
176 * BPF_REG_FP, BPF_REG_AX and Tail call counts.
177 */
178 #define SCRATCH_SIZE 96
179
180 /* Total stack size used in JITed code */
181 #define _STACK_SIZE (stack_depth + SCRATCH_SIZE)
182
183 #define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT)
184
185 /* Get the offset of eBPF REGISTERs stored on scratch space. */
186 #define STACK_VAR(off) (off)
187
188 /* Encode 'dst_reg' register into IA32 opcode 'byte' */
add_1reg(u8 byte,u32 dst_reg)189 static u8 add_1reg(u8 byte, u32 dst_reg)
190 {
191 return byte + dst_reg;
192 }
193
194 /* Encode 'dst_reg' and 'src_reg' registers into IA32 opcode 'byte' */
add_2reg(u8 byte,u32 dst_reg,u32 src_reg)195 static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
196 {
197 return byte + dst_reg + (src_reg << 3);
198 }
199
jit_fill_hole(void * area,unsigned int size)200 static void jit_fill_hole(void *area, unsigned int size)
201 {
202 /* Fill whole space with int3 instructions */
203 memset(area, 0xcc, size);
204 }
205
emit_ia32_mov_i(const u8 dst,const u32 val,bool dstk,u8 ** pprog)206 static inline void emit_ia32_mov_i(const u8 dst, const u32 val, bool dstk,
207 u8 **pprog)
208 {
209 u8 *prog = *pprog;
210 int cnt = 0;
211
212 if (dstk) {
213 if (val == 0) {
214 /* xor eax,eax */
215 EMIT2(0x33, add_2reg(0xC0, IA32_EAX, IA32_EAX));
216 /* mov dword ptr [ebp+off],eax */
217 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
218 STACK_VAR(dst));
219 } else {
220 EMIT3_off32(0xC7, add_1reg(0x40, IA32_EBP),
221 STACK_VAR(dst), val);
222 }
223 } else {
224 if (val == 0)
225 EMIT2(0x33, add_2reg(0xC0, dst, dst));
226 else
227 EMIT2_off32(0xC7, add_1reg(0xC0, dst),
228 val);
229 }
230 *pprog = prog;
231 }
232
233 /* dst = imm (4 bytes)*/
emit_ia32_mov_r(const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)234 static inline void emit_ia32_mov_r(const u8 dst, const u8 src, bool dstk,
235 bool sstk, u8 **pprog)
236 {
237 u8 *prog = *pprog;
238 int cnt = 0;
239 u8 sreg = sstk ? IA32_EAX : src;
240
241 if (sstk)
242 /* mov eax,dword ptr [ebp+off] */
243 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(src));
244 if (dstk)
245 /* mov dword ptr [ebp+off],eax */
246 EMIT3(0x89, add_2reg(0x40, IA32_EBP, sreg), STACK_VAR(dst));
247 else
248 /* mov dst,sreg */
249 EMIT2(0x89, add_2reg(0xC0, dst, sreg));
250
251 *pprog = prog;
252 }
253
254 /* 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)255 static inline void emit_ia32_mov_r64(const bool is64, const u8 dst[],
256 const u8 src[], bool dstk,
257 bool sstk, u8 **pprog,
258 const struct bpf_prog_aux *aux)
259 {
260 emit_ia32_mov_r(dst_lo, src_lo, dstk, sstk, pprog);
261 if (is64)
262 /* complete 8 byte move */
263 emit_ia32_mov_r(dst_hi, src_hi, dstk, sstk, pprog);
264 else if (!aux->verifier_zext)
265 /* zero out high 4 bytes */
266 emit_ia32_mov_i(dst_hi, 0, dstk, pprog);
267 }
268
269 /* Sign extended move */
emit_ia32_mov_i64(const bool is64,const u8 dst[],const u32 val,bool dstk,u8 ** pprog)270 static inline void emit_ia32_mov_i64(const bool is64, const u8 dst[],
271 const u32 val, bool dstk, u8 **pprog)
272 {
273 u32 hi = 0;
274
275 if (is64 && (val & (1<<31)))
276 hi = (u32)~0;
277 emit_ia32_mov_i(dst_lo, val, dstk, pprog);
278 emit_ia32_mov_i(dst_hi, hi, dstk, pprog);
279 }
280
281 /*
282 * ALU operation (32 bit)
283 * dst = dst * src
284 */
emit_ia32_mul_r(const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)285 static inline void emit_ia32_mul_r(const u8 dst, const u8 src, bool dstk,
286 bool sstk, u8 **pprog)
287 {
288 u8 *prog = *pprog;
289 int cnt = 0;
290 u8 sreg = sstk ? IA32_ECX : src;
291
292 if (sstk)
293 /* mov ecx,dword ptr [ebp+off] */
294 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src));
295
296 if (dstk)
297 /* mov eax,dword ptr [ebp+off] */
298 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
299 else
300 /* mov eax,dst */
301 EMIT2(0x8B, add_2reg(0xC0, dst, IA32_EAX));
302
303
304 EMIT2(0xF7, add_1reg(0xE0, sreg));
305
306 if (dstk)
307 /* mov dword ptr [ebp+off],eax */
308 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
309 STACK_VAR(dst));
310 else
311 /* mov dst,eax */
312 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EAX));
313
314 *pprog = prog;
315 }
316
emit_ia32_to_le_r64(const u8 dst[],s32 val,bool dstk,u8 ** pprog,const struct bpf_prog_aux * aux)317 static inline void emit_ia32_to_le_r64(const u8 dst[], s32 val,
318 bool dstk, u8 **pprog,
319 const struct bpf_prog_aux *aux)
320 {
321 u8 *prog = *pprog;
322 int cnt = 0;
323 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
324 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
325
326 if (dstk && val != 64) {
327 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
328 STACK_VAR(dst_lo));
329 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
330 STACK_VAR(dst_hi));
331 }
332 switch (val) {
333 case 16:
334 /*
335 * Emit 'movzwl eax,ax' to zero extend 16-bit
336 * into 64 bit
337 */
338 EMIT2(0x0F, 0xB7);
339 EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
340 if (!aux->verifier_zext)
341 /* xor dreg_hi,dreg_hi */
342 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
343 break;
344 case 32:
345 if (!aux->verifier_zext)
346 /* xor dreg_hi,dreg_hi */
347 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
348 break;
349 case 64:
350 /* nop */
351 break;
352 }
353
354 if (dstk && val != 64) {
355 /* mov dword ptr [ebp+off],dreg_lo */
356 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
357 STACK_VAR(dst_lo));
358 /* mov dword ptr [ebp+off],dreg_hi */
359 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
360 STACK_VAR(dst_hi));
361 }
362 *pprog = prog;
363 }
364
emit_ia32_to_be_r64(const u8 dst[],s32 val,bool dstk,u8 ** pprog,const struct bpf_prog_aux * aux)365 static inline void emit_ia32_to_be_r64(const u8 dst[], s32 val,
366 bool dstk, u8 **pprog,
367 const struct bpf_prog_aux *aux)
368 {
369 u8 *prog = *pprog;
370 int cnt = 0;
371 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
372 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
373
374 if (dstk) {
375 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
376 STACK_VAR(dst_lo));
377 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
378 STACK_VAR(dst_hi));
379 }
380 switch (val) {
381 case 16:
382 /* Emit 'ror %ax, 8' to swap lower 2 bytes */
383 EMIT1(0x66);
384 EMIT3(0xC1, add_1reg(0xC8, dreg_lo), 8);
385
386 EMIT2(0x0F, 0xB7);
387 EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
388
389 if (!aux->verifier_zext)
390 /* xor dreg_hi,dreg_hi */
391 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
392 break;
393 case 32:
394 /* Emit 'bswap eax' to swap lower 4 bytes */
395 EMIT1(0x0F);
396 EMIT1(add_1reg(0xC8, dreg_lo));
397
398 if (!aux->verifier_zext)
399 /* xor dreg_hi,dreg_hi */
400 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
401 break;
402 case 64:
403 /* Emit 'bswap eax' to swap lower 4 bytes */
404 EMIT1(0x0F);
405 EMIT1(add_1reg(0xC8, dreg_lo));
406
407 /* Emit 'bswap edx' to swap lower 4 bytes */
408 EMIT1(0x0F);
409 EMIT1(add_1reg(0xC8, dreg_hi));
410
411 /* mov ecx,dreg_hi */
412 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, dreg_hi));
413 /* mov dreg_hi,dreg_lo */
414 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
415 /* mov dreg_lo,ecx */
416 EMIT2(0x89, add_2reg(0xC0, dreg_lo, IA32_ECX));
417
418 break;
419 }
420 if (dstk) {
421 /* mov dword ptr [ebp+off],dreg_lo */
422 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
423 STACK_VAR(dst_lo));
424 /* mov dword ptr [ebp+off],dreg_hi */
425 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
426 STACK_VAR(dst_hi));
427 }
428 *pprog = prog;
429 }
430
431 /*
432 * ALU operation (32 bit)
433 * dst = dst (div|mod) src
434 */
emit_ia32_div_mod_r(const u8 op,const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)435 static inline void emit_ia32_div_mod_r(const u8 op, const u8 dst, const u8 src,
436 bool dstk, bool sstk, u8 **pprog)
437 {
438 u8 *prog = *pprog;
439 int cnt = 0;
440
441 if (sstk)
442 /* mov ecx,dword ptr [ebp+off] */
443 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
444 STACK_VAR(src));
445 else if (src != IA32_ECX)
446 /* mov ecx,src */
447 EMIT2(0x8B, add_2reg(0xC0, src, IA32_ECX));
448
449 if (dstk)
450 /* mov eax,dword ptr [ebp+off] */
451 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
452 STACK_VAR(dst));
453 else
454 /* mov eax,dst */
455 EMIT2(0x8B, add_2reg(0xC0, dst, IA32_EAX));
456
457 /* xor edx,edx */
458 EMIT2(0x31, add_2reg(0xC0, IA32_EDX, IA32_EDX));
459 /* div ecx */
460 EMIT2(0xF7, add_1reg(0xF0, IA32_ECX));
461
462 if (op == BPF_MOD) {
463 if (dstk)
464 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
465 STACK_VAR(dst));
466 else
467 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EDX));
468 } else {
469 if (dstk)
470 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
471 STACK_VAR(dst));
472 else
473 EMIT2(0x89, add_2reg(0xC0, dst, IA32_EAX));
474 }
475 *pprog = prog;
476 }
477
478 /*
479 * ALU operation (32 bit)
480 * dst = dst (shift) src
481 */
emit_ia32_shift_r(const u8 op,const u8 dst,const u8 src,bool dstk,bool sstk,u8 ** pprog)482 static inline void emit_ia32_shift_r(const u8 op, const u8 dst, const u8 src,
483 bool dstk, bool sstk, u8 **pprog)
484 {
485 u8 *prog = *pprog;
486 int cnt = 0;
487 u8 dreg = dstk ? IA32_EAX : dst;
488 u8 b2;
489
490 if (dstk)
491 /* mov eax,dword ptr [ebp+off] */
492 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
493
494 if (sstk)
495 /* mov ecx,dword ptr [ebp+off] */
496 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src));
497 else if (src != IA32_ECX)
498 /* mov ecx,src */
499 EMIT2(0x8B, add_2reg(0xC0, src, IA32_ECX));
500
501 switch (op) {
502 case BPF_LSH:
503 b2 = 0xE0; break;
504 case BPF_RSH:
505 b2 = 0xE8; break;
506 case BPF_ARSH:
507 b2 = 0xF8; break;
508 default:
509 return;
510 }
511 EMIT2(0xD3, add_1reg(b2, dreg));
512
513 if (dstk)
514 /* mov dword ptr [ebp+off],dreg */
515 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg), STACK_VAR(dst));
516 *pprog = prog;
517 }
518
519 /*
520 * ALU operation (32 bit)
521 * dst = dst (op) src
522 */
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)523 static inline void emit_ia32_alu_r(const bool is64, const bool hi, const u8 op,
524 const u8 dst, const u8 src, bool dstk,
525 bool sstk, u8 **pprog)
526 {
527 u8 *prog = *pprog;
528 int cnt = 0;
529 u8 sreg = sstk ? IA32_EAX : src;
530 u8 dreg = dstk ? IA32_EDX : dst;
531
532 if (sstk)
533 /* mov eax,dword ptr [ebp+off] */
534 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(src));
535
536 if (dstk)
537 /* mov eax,dword ptr [ebp+off] */
538 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(dst));
539
540 switch (BPF_OP(op)) {
541 /* dst = dst + src */
542 case BPF_ADD:
543 if (hi && is64)
544 EMIT2(0x11, add_2reg(0xC0, dreg, sreg));
545 else
546 EMIT2(0x01, add_2reg(0xC0, dreg, sreg));
547 break;
548 /* dst = dst - src */
549 case BPF_SUB:
550 if (hi && is64)
551 EMIT2(0x19, add_2reg(0xC0, dreg, sreg));
552 else
553 EMIT2(0x29, add_2reg(0xC0, dreg, sreg));
554 break;
555 /* dst = dst | src */
556 case BPF_OR:
557 EMIT2(0x09, add_2reg(0xC0, dreg, sreg));
558 break;
559 /* dst = dst & src */
560 case BPF_AND:
561 EMIT2(0x21, add_2reg(0xC0, dreg, sreg));
562 break;
563 /* dst = dst ^ src */
564 case BPF_XOR:
565 EMIT2(0x31, add_2reg(0xC0, dreg, sreg));
566 break;
567 }
568
569 if (dstk)
570 /* mov dword ptr [ebp+off],dreg */
571 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg),
572 STACK_VAR(dst));
573 *pprog = prog;
574 }
575
576 /* 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)577 static inline void emit_ia32_alu_r64(const bool is64, const u8 op,
578 const u8 dst[], const u8 src[],
579 bool dstk, bool sstk,
580 u8 **pprog, const struct bpf_prog_aux *aux)
581 {
582 u8 *prog = *pprog;
583
584 emit_ia32_alu_r(is64, false, op, dst_lo, src_lo, dstk, sstk, &prog);
585 if (is64)
586 emit_ia32_alu_r(is64, true, op, dst_hi, src_hi, dstk, sstk,
587 &prog);
588 else if (!aux->verifier_zext)
589 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
590 *pprog = prog;
591 }
592
593 /*
594 * ALU operation (32 bit)
595 * dst = dst (op) val
596 */
emit_ia32_alu_i(const bool is64,const bool hi,const u8 op,const u8 dst,const s32 val,bool dstk,u8 ** pprog)597 static inline void emit_ia32_alu_i(const bool is64, const bool hi, const u8 op,
598 const u8 dst, const s32 val, bool dstk,
599 u8 **pprog)
600 {
601 u8 *prog = *pprog;
602 int cnt = 0;
603 u8 dreg = dstk ? IA32_EAX : dst;
604 u8 sreg = IA32_EDX;
605
606 if (dstk)
607 /* mov eax,dword ptr [ebp+off] */
608 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(dst));
609
610 if (!is_imm8(val))
611 /* mov edx,imm32*/
612 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EDX), val);
613
614 switch (op) {
615 /* dst = dst + val */
616 case BPF_ADD:
617 if (hi && is64) {
618 if (is_imm8(val))
619 EMIT3(0x83, add_1reg(0xD0, dreg), val);
620 else
621 EMIT2(0x11, add_2reg(0xC0, dreg, sreg));
622 } else {
623 if (is_imm8(val))
624 EMIT3(0x83, add_1reg(0xC0, dreg), val);
625 else
626 EMIT2(0x01, add_2reg(0xC0, dreg, sreg));
627 }
628 break;
629 /* dst = dst - val */
630 case BPF_SUB:
631 if (hi && is64) {
632 if (is_imm8(val))
633 EMIT3(0x83, add_1reg(0xD8, dreg), val);
634 else
635 EMIT2(0x19, add_2reg(0xC0, dreg, sreg));
636 } else {
637 if (is_imm8(val))
638 EMIT3(0x83, add_1reg(0xE8, dreg), val);
639 else
640 EMIT2(0x29, add_2reg(0xC0, dreg, sreg));
641 }
642 break;
643 /* dst = dst | val */
644 case BPF_OR:
645 if (is_imm8(val))
646 EMIT3(0x83, add_1reg(0xC8, dreg), val);
647 else
648 EMIT2(0x09, add_2reg(0xC0, dreg, sreg));
649 break;
650 /* dst = dst & val */
651 case BPF_AND:
652 if (is_imm8(val))
653 EMIT3(0x83, add_1reg(0xE0, dreg), val);
654 else
655 EMIT2(0x21, add_2reg(0xC0, dreg, sreg));
656 break;
657 /* dst = dst ^ val */
658 case BPF_XOR:
659 if (is_imm8(val))
660 EMIT3(0x83, add_1reg(0xF0, dreg), val);
661 else
662 EMIT2(0x31, add_2reg(0xC0, dreg, sreg));
663 break;
664 case BPF_NEG:
665 EMIT2(0xF7, add_1reg(0xD8, dreg));
666 break;
667 }
668
669 if (dstk)
670 /* mov dword ptr [ebp+off],dreg */
671 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg),
672 STACK_VAR(dst));
673 *pprog = prog;
674 }
675
676 /* 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)677 static inline void emit_ia32_alu_i64(const bool is64, const u8 op,
678 const u8 dst[], const u32 val,
679 bool dstk, u8 **pprog,
680 const struct bpf_prog_aux *aux)
681 {
682 u8 *prog = *pprog;
683 u32 hi = 0;
684
685 if (is64 && (val & (1<<31)))
686 hi = (u32)~0;
687
688 emit_ia32_alu_i(is64, false, op, dst_lo, val, dstk, &prog);
689 if (is64)
690 emit_ia32_alu_i(is64, true, op, dst_hi, hi, dstk, &prog);
691 else if (!aux->verifier_zext)
692 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
693
694 *pprog = prog;
695 }
696
697 /* dst = ~dst (64 bit) */
emit_ia32_neg64(const u8 dst[],bool dstk,u8 ** pprog)698 static inline void emit_ia32_neg64(const u8 dst[], bool dstk, u8 **pprog)
699 {
700 u8 *prog = *pprog;
701 int cnt = 0;
702 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
703 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
704
705 if (dstk) {
706 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
707 STACK_VAR(dst_lo));
708 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
709 STACK_VAR(dst_hi));
710 }
711
712 /* neg dreg_lo */
713 EMIT2(0xF7, add_1reg(0xD8, dreg_lo));
714 /* adc dreg_hi,0x0 */
715 EMIT3(0x83, add_1reg(0xD0, dreg_hi), 0x00);
716 /* neg dreg_hi */
717 EMIT2(0xF7, add_1reg(0xD8, dreg_hi));
718
719 if (dstk) {
720 /* mov dword ptr [ebp+off],dreg_lo */
721 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
722 STACK_VAR(dst_lo));
723 /* mov dword ptr [ebp+off],dreg_hi */
724 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
725 STACK_VAR(dst_hi));
726 }
727 *pprog = prog;
728 }
729
730 /* dst = dst << src */
emit_ia32_lsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)731 static inline void emit_ia32_lsh_r64(const u8 dst[], const u8 src[],
732 bool dstk, bool sstk, u8 **pprog)
733 {
734 u8 *prog = *pprog;
735 int cnt = 0;
736 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
737 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
738
739 if (dstk) {
740 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
741 STACK_VAR(dst_lo));
742 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
743 STACK_VAR(dst_hi));
744 }
745
746 if (sstk)
747 /* mov ecx,dword ptr [ebp+off] */
748 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
749 STACK_VAR(src_lo));
750 else
751 /* mov ecx,src_lo */
752 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
753
754 /* shld dreg_hi,dreg_lo,cl */
755 EMIT3(0x0F, 0xA5, add_2reg(0xC0, dreg_hi, dreg_lo));
756 /* shl dreg_lo,cl */
757 EMIT2(0xD3, add_1reg(0xE0, dreg_lo));
758
759 /* if ecx >= 32, mov dreg_lo into dreg_hi and clear dreg_lo */
760
761 /* cmp ecx,32 */
762 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
763 /* skip the next two instructions (4 bytes) when < 32 */
764 EMIT2(IA32_JB, 4);
765
766 /* mov dreg_hi,dreg_lo */
767 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
768 /* xor dreg_lo,dreg_lo */
769 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
770
771 if (dstk) {
772 /* mov dword ptr [ebp+off],dreg_lo */
773 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
774 STACK_VAR(dst_lo));
775 /* mov dword ptr [ebp+off],dreg_hi */
776 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
777 STACK_VAR(dst_hi));
778 }
779 /* out: */
780 *pprog = prog;
781 }
782
783 /* dst = dst >> src (signed)*/
emit_ia32_arsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)784 static inline void emit_ia32_arsh_r64(const u8 dst[], const u8 src[],
785 bool dstk, bool sstk, u8 **pprog)
786 {
787 u8 *prog = *pprog;
788 int cnt = 0;
789 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
790 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
791
792 if (dstk) {
793 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
794 STACK_VAR(dst_lo));
795 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
796 STACK_VAR(dst_hi));
797 }
798
799 if (sstk)
800 /* mov ecx,dword ptr [ebp+off] */
801 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
802 STACK_VAR(src_lo));
803 else
804 /* mov ecx,src_lo */
805 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
806
807 /* shrd dreg_lo,dreg_hi,cl */
808 EMIT3(0x0F, 0xAD, add_2reg(0xC0, dreg_lo, dreg_hi));
809 /* sar dreg_hi,cl */
810 EMIT2(0xD3, add_1reg(0xF8, dreg_hi));
811
812 /* if ecx >= 32, mov dreg_hi to dreg_lo and set/clear dreg_hi depending on sign */
813
814 /* cmp ecx,32 */
815 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
816 /* skip the next two instructions (5 bytes) when < 32 */
817 EMIT2(IA32_JB, 5);
818
819 /* mov dreg_lo,dreg_hi */
820 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
821 /* sar dreg_hi,31 */
822 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
823
824 if (dstk) {
825 /* mov dword ptr [ebp+off],dreg_lo */
826 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
827 STACK_VAR(dst_lo));
828 /* mov dword ptr [ebp+off],dreg_hi */
829 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
830 STACK_VAR(dst_hi));
831 }
832 /* out: */
833 *pprog = prog;
834 }
835
836 /* dst = dst >> src */
emit_ia32_rsh_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)837 static inline void emit_ia32_rsh_r64(const u8 dst[], const u8 src[], bool dstk,
838 bool sstk, u8 **pprog)
839 {
840 u8 *prog = *pprog;
841 int cnt = 0;
842 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
843 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
844
845 if (dstk) {
846 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
847 STACK_VAR(dst_lo));
848 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
849 STACK_VAR(dst_hi));
850 }
851
852 if (sstk)
853 /* mov ecx,dword ptr [ebp+off] */
854 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
855 STACK_VAR(src_lo));
856 else
857 /* mov ecx,src_lo */
858 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_ECX));
859
860 /* shrd dreg_lo,dreg_hi,cl */
861 EMIT3(0x0F, 0xAD, add_2reg(0xC0, dreg_lo, dreg_hi));
862 /* shr dreg_hi,cl */
863 EMIT2(0xD3, add_1reg(0xE8, dreg_hi));
864
865 /* if ecx >= 32, mov dreg_hi to dreg_lo and clear dreg_hi */
866
867 /* cmp ecx,32 */
868 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), 32);
869 /* skip the next two instructions (4 bytes) when < 32 */
870 EMIT2(IA32_JB, 4);
871
872 /* mov dreg_lo,dreg_hi */
873 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
874 /* xor dreg_hi,dreg_hi */
875 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
876
877 if (dstk) {
878 /* mov dword ptr [ebp+off],dreg_lo */
879 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
880 STACK_VAR(dst_lo));
881 /* mov dword ptr [ebp+off],dreg_hi */
882 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
883 STACK_VAR(dst_hi));
884 }
885 /* out: */
886 *pprog = prog;
887 }
888
889 /* dst = dst << val */
emit_ia32_lsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)890 static inline void emit_ia32_lsh_i64(const u8 dst[], const u32 val,
891 bool dstk, u8 **pprog)
892 {
893 u8 *prog = *pprog;
894 int cnt = 0;
895 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
896 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
897
898 if (dstk) {
899 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
900 STACK_VAR(dst_lo));
901 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
902 STACK_VAR(dst_hi));
903 }
904 /* Do LSH operation */
905 if (val < 32) {
906 /* shld dreg_hi,dreg_lo,imm8 */
907 EMIT4(0x0F, 0xA4, add_2reg(0xC0, dreg_hi, dreg_lo), val);
908 /* shl dreg_lo,imm8 */
909 EMIT3(0xC1, add_1reg(0xE0, dreg_lo), val);
910 } else if (val >= 32 && val < 64) {
911 u32 value = val - 32;
912
913 /* shl dreg_lo,imm8 */
914 EMIT3(0xC1, add_1reg(0xE0, dreg_lo), value);
915 /* mov dreg_hi,dreg_lo */
916 EMIT2(0x89, add_2reg(0xC0, dreg_hi, dreg_lo));
917 /* xor dreg_lo,dreg_lo */
918 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
919 } else {
920 /* xor dreg_lo,dreg_lo */
921 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
922 /* xor dreg_hi,dreg_hi */
923 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
924 }
925
926 if (dstk) {
927 /* mov dword ptr [ebp+off],dreg_lo */
928 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
929 STACK_VAR(dst_lo));
930 /* mov dword ptr [ebp+off],dreg_hi */
931 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
932 STACK_VAR(dst_hi));
933 }
934 *pprog = prog;
935 }
936
937 /* dst = dst >> val */
emit_ia32_rsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)938 static inline void emit_ia32_rsh_i64(const u8 dst[], const u32 val,
939 bool dstk, u8 **pprog)
940 {
941 u8 *prog = *pprog;
942 int cnt = 0;
943 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
944 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
945
946 if (dstk) {
947 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
948 STACK_VAR(dst_lo));
949 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
950 STACK_VAR(dst_hi));
951 }
952
953 /* Do RSH operation */
954 if (val < 32) {
955 /* shrd dreg_lo,dreg_hi,imm8 */
956 EMIT4(0x0F, 0xAC, add_2reg(0xC0, dreg_lo, dreg_hi), val);
957 /* shr dreg_hi,imm8 */
958 EMIT3(0xC1, add_1reg(0xE8, dreg_hi), val);
959 } else if (val >= 32 && val < 64) {
960 u32 value = val - 32;
961
962 /* shr dreg_hi,imm8 */
963 EMIT3(0xC1, add_1reg(0xE8, dreg_hi), value);
964 /* mov dreg_lo,dreg_hi */
965 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
966 /* xor dreg_hi,dreg_hi */
967 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
968 } else {
969 /* xor dreg_lo,dreg_lo */
970 EMIT2(0x33, add_2reg(0xC0, dreg_lo, dreg_lo));
971 /* xor dreg_hi,dreg_hi */
972 EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
973 }
974
975 if (dstk) {
976 /* mov dword ptr [ebp+off],dreg_lo */
977 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
978 STACK_VAR(dst_lo));
979 /* mov dword ptr [ebp+off],dreg_hi */
980 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
981 STACK_VAR(dst_hi));
982 }
983 *pprog = prog;
984 }
985
986 /* dst = dst >> val (signed) */
emit_ia32_arsh_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)987 static inline void emit_ia32_arsh_i64(const u8 dst[], const u32 val,
988 bool dstk, u8 **pprog)
989 {
990 u8 *prog = *pprog;
991 int cnt = 0;
992 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
993 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
994
995 if (dstk) {
996 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
997 STACK_VAR(dst_lo));
998 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
999 STACK_VAR(dst_hi));
1000 }
1001 /* Do RSH operation */
1002 if (val < 32) {
1003 /* shrd dreg_lo,dreg_hi,imm8 */
1004 EMIT4(0x0F, 0xAC, add_2reg(0xC0, dreg_lo, dreg_hi), val);
1005 /* ashr dreg_hi,imm8 */
1006 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), val);
1007 } else if (val >= 32 && val < 64) {
1008 u32 value = val - 32;
1009
1010 /* ashr dreg_hi,imm8 */
1011 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), value);
1012 /* mov dreg_lo,dreg_hi */
1013 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
1014
1015 /* ashr dreg_hi,imm8 */
1016 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
1017 } else {
1018 /* ashr dreg_hi,imm8 */
1019 EMIT3(0xC1, add_1reg(0xF8, dreg_hi), 31);
1020 /* mov dreg_lo,dreg_hi */
1021 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dreg_hi));
1022 }
1023
1024 if (dstk) {
1025 /* mov dword ptr [ebp+off],dreg_lo */
1026 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_lo),
1027 STACK_VAR(dst_lo));
1028 /* mov dword ptr [ebp+off],dreg_hi */
1029 EMIT3(0x89, add_2reg(0x40, IA32_EBP, dreg_hi),
1030 STACK_VAR(dst_hi));
1031 }
1032 *pprog = prog;
1033 }
1034
emit_ia32_mul_r64(const u8 dst[],const u8 src[],bool dstk,bool sstk,u8 ** pprog)1035 static inline void emit_ia32_mul_r64(const u8 dst[], const u8 src[], bool dstk,
1036 bool sstk, u8 **pprog)
1037 {
1038 u8 *prog = *pprog;
1039 int cnt = 0;
1040
1041 if (dstk)
1042 /* mov eax,dword ptr [ebp+off] */
1043 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1044 STACK_VAR(dst_hi));
1045 else
1046 /* mov eax,dst_hi */
1047 EMIT2(0x8B, add_2reg(0xC0, dst_hi, IA32_EAX));
1048
1049 if (sstk)
1050 /* mul dword ptr [ebp+off] */
1051 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_lo));
1052 else
1053 /* mul src_lo */
1054 EMIT2(0xF7, add_1reg(0xE0, src_lo));
1055
1056 /* mov ecx,eax */
1057 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1058
1059 if (dstk)
1060 /* mov eax,dword ptr [ebp+off] */
1061 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1062 STACK_VAR(dst_lo));
1063 else
1064 /* mov eax,dst_lo */
1065 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1066
1067 if (sstk)
1068 /* mul dword ptr [ebp+off] */
1069 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_hi));
1070 else
1071 /* mul src_hi */
1072 EMIT2(0xF7, add_1reg(0xE0, src_hi));
1073
1074 /* add eax,eax */
1075 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1076
1077 if (dstk)
1078 /* mov eax,dword ptr [ebp+off] */
1079 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1080 STACK_VAR(dst_lo));
1081 else
1082 /* mov eax,dst_lo */
1083 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1084
1085 if (sstk)
1086 /* mul dword ptr [ebp+off] */
1087 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(src_lo));
1088 else
1089 /* mul src_lo */
1090 EMIT2(0xF7, add_1reg(0xE0, src_lo));
1091
1092 /* add ecx,edx */
1093 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EDX));
1094
1095 if (dstk) {
1096 /* mov dword ptr [ebp+off],eax */
1097 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1098 STACK_VAR(dst_lo));
1099 /* mov dword ptr [ebp+off],ecx */
1100 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX),
1101 STACK_VAR(dst_hi));
1102 } else {
1103 /* mov dst_lo,eax */
1104 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EAX));
1105 /* mov dst_hi,ecx */
1106 EMIT2(0x89, add_2reg(0xC0, dst_hi, IA32_ECX));
1107 }
1108
1109 *pprog = prog;
1110 }
1111
emit_ia32_mul_i64(const u8 dst[],const u32 val,bool dstk,u8 ** pprog)1112 static inline void emit_ia32_mul_i64(const u8 dst[], const u32 val,
1113 bool dstk, u8 **pprog)
1114 {
1115 u8 *prog = *pprog;
1116 int cnt = 0;
1117 u32 hi;
1118
1119 hi = val & (1<<31) ? (u32)~0 : 0;
1120 /* movl eax,imm32 */
1121 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), val);
1122 if (dstk)
1123 /* mul dword ptr [ebp+off] */
1124 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_hi));
1125 else
1126 /* mul dst_hi */
1127 EMIT2(0xF7, add_1reg(0xE0, dst_hi));
1128
1129 /* mov ecx,eax */
1130 EMIT2(0x89, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1131
1132 /* movl eax,imm32 */
1133 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), hi);
1134 if (dstk)
1135 /* mul dword ptr [ebp+off] */
1136 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_lo));
1137 else
1138 /* mul dst_lo */
1139 EMIT2(0xF7, add_1reg(0xE0, dst_lo));
1140 /* add ecx,eax */
1141 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EAX));
1142
1143 /* movl eax,imm32 */
1144 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EAX), val);
1145 if (dstk)
1146 /* mul dword ptr [ebp+off] */
1147 EMIT3(0xF7, add_1reg(0x60, IA32_EBP), STACK_VAR(dst_lo));
1148 else
1149 /* mul dst_lo */
1150 EMIT2(0xF7, add_1reg(0xE0, dst_lo));
1151
1152 /* add ecx,edx */
1153 EMIT2(0x01, add_2reg(0xC0, IA32_ECX, IA32_EDX));
1154
1155 if (dstk) {
1156 /* mov dword ptr [ebp+off],eax */
1157 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1158 STACK_VAR(dst_lo));
1159 /* mov dword ptr [ebp+off],ecx */
1160 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX),
1161 STACK_VAR(dst_hi));
1162 } else {
1163 /* mov dword ptr [ebp+off],eax */
1164 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EAX));
1165 /* mov dword ptr [ebp+off],ecx */
1166 EMIT2(0x89, add_2reg(0xC0, dst_hi, IA32_ECX));
1167 }
1168
1169 *pprog = prog;
1170 }
1171
bpf_size_to_x86_bytes(int bpf_size)1172 static int bpf_size_to_x86_bytes(int bpf_size)
1173 {
1174 if (bpf_size == BPF_W)
1175 return 4;
1176 else if (bpf_size == BPF_H)
1177 return 2;
1178 else if (bpf_size == BPF_B)
1179 return 1;
1180 else if (bpf_size == BPF_DW)
1181 return 4; /* imm32 */
1182 else
1183 return 0;
1184 }
1185
1186 struct jit_context {
1187 int cleanup_addr; /* Epilogue code offset */
1188 };
1189
1190 /* Maximum number of bytes emitted while JITing one eBPF insn */
1191 #define BPF_MAX_INSN_SIZE 128
1192 #define BPF_INSN_SAFETY 64
1193
1194 #define PROLOGUE_SIZE 35
1195
1196 /*
1197 * Emit prologue code for BPF program and check its size.
1198 * bpf_tail_call helper will skip it while jumping into another program.
1199 */
emit_prologue(u8 ** pprog,u32 stack_depth)1200 static void emit_prologue(u8 **pprog, u32 stack_depth)
1201 {
1202 u8 *prog = *pprog;
1203 int cnt = 0;
1204 const u8 *r1 = bpf2ia32[BPF_REG_1];
1205 const u8 fplo = bpf2ia32[BPF_REG_FP][0];
1206 const u8 fphi = bpf2ia32[BPF_REG_FP][1];
1207 const u8 *tcc = bpf2ia32[TCALL_CNT];
1208
1209 /* push ebp */
1210 EMIT1(0x55);
1211 /* mov ebp,esp */
1212 EMIT2(0x89, 0xE5);
1213 /* push edi */
1214 EMIT1(0x57);
1215 /* push esi */
1216 EMIT1(0x56);
1217 /* push ebx */
1218 EMIT1(0x53);
1219
1220 /* sub esp,STACK_SIZE */
1221 EMIT2_off32(0x81, 0xEC, STACK_SIZE);
1222 /* sub ebp,SCRATCH_SIZE+12*/
1223 EMIT3(0x83, add_1reg(0xE8, IA32_EBP), SCRATCH_SIZE + 12);
1224 /* xor ebx,ebx */
1225 EMIT2(0x31, add_2reg(0xC0, IA32_EBX, IA32_EBX));
1226
1227 /* Set up BPF prog stack base register */
1228 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBP), STACK_VAR(fplo));
1229 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(fphi));
1230
1231 /* Move BPF_CTX (EAX) to BPF_REG_R1 */
1232 /* mov dword ptr [ebp+off],eax */
1233 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r1[0]));
1234 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(r1[1]));
1235
1236 /* Initialize Tail Count */
1237 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[0]));
1238 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1239
1240 BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
1241 *pprog = prog;
1242 }
1243
1244 /* Emit epilogue code for BPF program */
emit_epilogue(u8 ** pprog,u32 stack_depth)1245 static void emit_epilogue(u8 **pprog, u32 stack_depth)
1246 {
1247 u8 *prog = *pprog;
1248 const u8 *r0 = bpf2ia32[BPF_REG_0];
1249 int cnt = 0;
1250
1251 /* mov eax,dword ptr [ebp+off]*/
1252 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r0[0]));
1253 /* mov edx,dword ptr [ebp+off]*/
1254 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(r0[1]));
1255
1256 /* add ebp,SCRATCH_SIZE+12*/
1257 EMIT3(0x83, add_1reg(0xC0, IA32_EBP), SCRATCH_SIZE + 12);
1258
1259 /* mov ebx,dword ptr [ebp-12]*/
1260 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EBX), -12);
1261 /* mov esi,dword ptr [ebp-8]*/
1262 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ESI), -8);
1263 /* mov edi,dword ptr [ebp-4]*/
1264 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDI), -4);
1265
1266 EMIT1(0xC9); /* leave */
1267 EMIT1(0xC3); /* ret */
1268 *pprog = prog;
1269 }
1270
emit_jmp_edx(u8 ** pprog,u8 * ip)1271 static int emit_jmp_edx(u8 **pprog, u8 *ip)
1272 {
1273 u8 *prog = *pprog;
1274 int cnt = 0;
1275
1276 #ifdef CONFIG_MITIGATION_RETPOLINE
1277 EMIT1_off32(0xE9, (u8 *)__x86_indirect_thunk_edx - (ip + 5));
1278 #else
1279 EMIT2(0xFF, 0xE2);
1280 #endif
1281 *pprog = prog;
1282
1283 return cnt;
1284 }
1285
1286 /*
1287 * Generate the following code:
1288 * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
1289 * if (index >= array->map.max_entries)
1290 * goto out;
1291 * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
1292 * goto out;
1293 * prog = array->ptrs[index];
1294 * if (prog == NULL)
1295 * goto out;
1296 * goto *(prog->bpf_func + prologue_size);
1297 * out:
1298 */
emit_bpf_tail_call(u8 ** pprog,u8 * ip)1299 static void emit_bpf_tail_call(u8 **pprog, u8 *ip)
1300 {
1301 u8 *prog = *pprog;
1302 int cnt = 0;
1303 const u8 *r1 = bpf2ia32[BPF_REG_1];
1304 const u8 *r2 = bpf2ia32[BPF_REG_2];
1305 const u8 *r3 = bpf2ia32[BPF_REG_3];
1306 const u8 *tcc = bpf2ia32[TCALL_CNT];
1307 u32 lo, hi;
1308 static int jmp_label1 = -1;
1309
1310 /*
1311 * if (index >= array->map.max_entries)
1312 * goto out;
1313 */
1314 /* mov eax,dword ptr [ebp+off] */
1315 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r2[0]));
1316 /* mov edx,dword ptr [ebp+off] */
1317 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX), STACK_VAR(r3[0]));
1318
1319 /* cmp dword ptr [eax+off],edx */
1320 EMIT3(0x39, add_2reg(0x40, IA32_EAX, IA32_EDX),
1321 offsetof(struct bpf_array, map.max_entries));
1322 /* jbe out */
1323 EMIT2(IA32_JBE, jmp_label(jmp_label1, 2));
1324
1325 /*
1326 * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
1327 * goto out;
1328 */
1329 lo = (u32)MAX_TAIL_CALL_CNT;
1330 hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32);
1331 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(tcc[0]));
1332 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1333
1334 /* cmp edx,hi */
1335 EMIT3(0x83, add_1reg(0xF8, IA32_EBX), hi);
1336 EMIT2(IA32_JNE, 3);
1337 /* cmp ecx,lo */
1338 EMIT3(0x83, add_1reg(0xF8, IA32_ECX), lo);
1339
1340 /* jae out */
1341 EMIT2(IA32_JAE, jmp_label(jmp_label1, 2));
1342
1343 /* add eax,0x1 */
1344 EMIT3(0x83, add_1reg(0xC0, IA32_ECX), 0x01);
1345 /* adc ebx,0x0 */
1346 EMIT3(0x83, add_1reg(0xD0, IA32_EBX), 0x00);
1347
1348 /* mov dword ptr [ebp+off],eax */
1349 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(tcc[0]));
1350 /* mov dword ptr [ebp+off],edx */
1351 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EBX), STACK_VAR(tcc[1]));
1352
1353 /* prog = array->ptrs[index]; */
1354 /* mov edx, [eax + edx * 4 + offsetof(...)] */
1355 EMIT3_off32(0x8B, 0x94, 0x90, offsetof(struct bpf_array, ptrs));
1356
1357 /*
1358 * if (prog == NULL)
1359 * goto out;
1360 */
1361 /* test edx,edx */
1362 EMIT2(0x85, add_2reg(0xC0, IA32_EDX, IA32_EDX));
1363 /* je out */
1364 EMIT2(IA32_JE, jmp_label(jmp_label1, 2));
1365
1366 /* goto *(prog->bpf_func + prologue_size); */
1367 /* mov edx, dword ptr [edx + 32] */
1368 EMIT3(0x8B, add_2reg(0x40, IA32_EDX, IA32_EDX),
1369 offsetof(struct bpf_prog, bpf_func));
1370 /* add edx,prologue_size */
1371 EMIT3(0x83, add_1reg(0xC0, IA32_EDX), PROLOGUE_SIZE);
1372
1373 /* mov eax,dword ptr [ebp+off] */
1374 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX), STACK_VAR(r1[0]));
1375
1376 /*
1377 * Now we're ready to jump into next BPF program:
1378 * eax == ctx (1st arg)
1379 * edx == prog->bpf_func + prologue_size
1380 */
1381 cnt += emit_jmp_edx(&prog, ip + cnt);
1382
1383 if (jmp_label1 == -1)
1384 jmp_label1 = cnt;
1385
1386 /* out: */
1387 *pprog = prog;
1388 }
1389
1390 /* Push the scratch stack register on top of the stack. */
emit_push_r64(const u8 src[],u8 ** pprog)1391 static inline void emit_push_r64(const u8 src[], u8 **pprog)
1392 {
1393 u8 *prog = *pprog;
1394 int cnt = 0;
1395
1396 /* mov ecx,dword ptr [ebp+off] */
1397 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src_hi));
1398 /* push ecx */
1399 EMIT1(0x51);
1400
1401 /* mov ecx,dword ptr [ebp+off] */
1402 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src_lo));
1403 /* push ecx */
1404 EMIT1(0x51);
1405
1406 *pprog = prog;
1407 }
1408
emit_push_r32(const u8 src[],u8 ** pprog)1409 static void emit_push_r32(const u8 src[], u8 **pprog)
1410 {
1411 u8 *prog = *pprog;
1412 int cnt = 0;
1413
1414 /* mov ecx,dword ptr [ebp+off] */
1415 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX), STACK_VAR(src_lo));
1416 /* push ecx */
1417 EMIT1(0x51);
1418
1419 *pprog = prog;
1420 }
1421
get_cond_jmp_opcode(const u8 op,bool is_cmp_lo)1422 static u8 get_cond_jmp_opcode(const u8 op, bool is_cmp_lo)
1423 {
1424 u8 jmp_cond;
1425
1426 /* Convert BPF opcode to x86 */
1427 switch (op) {
1428 case BPF_JEQ:
1429 jmp_cond = IA32_JE;
1430 break;
1431 case BPF_JSET:
1432 case BPF_JNE:
1433 jmp_cond = IA32_JNE;
1434 break;
1435 case BPF_JGT:
1436 /* GT is unsigned '>', JA in x86 */
1437 jmp_cond = IA32_JA;
1438 break;
1439 case BPF_JLT:
1440 /* LT is unsigned '<', JB in x86 */
1441 jmp_cond = IA32_JB;
1442 break;
1443 case BPF_JGE:
1444 /* GE is unsigned '>=', JAE in x86 */
1445 jmp_cond = IA32_JAE;
1446 break;
1447 case BPF_JLE:
1448 /* LE is unsigned '<=', JBE in x86 */
1449 jmp_cond = IA32_JBE;
1450 break;
1451 case BPF_JSGT:
1452 if (!is_cmp_lo)
1453 /* Signed '>', GT in x86 */
1454 jmp_cond = IA32_JG;
1455 else
1456 /* GT is unsigned '>', JA in x86 */
1457 jmp_cond = IA32_JA;
1458 break;
1459 case BPF_JSLT:
1460 if (!is_cmp_lo)
1461 /* Signed '<', LT in x86 */
1462 jmp_cond = IA32_JL;
1463 else
1464 /* LT is unsigned '<', JB in x86 */
1465 jmp_cond = IA32_JB;
1466 break;
1467 case BPF_JSGE:
1468 if (!is_cmp_lo)
1469 /* Signed '>=', GE in x86 */
1470 jmp_cond = IA32_JGE;
1471 else
1472 /* GE is unsigned '>=', JAE in x86 */
1473 jmp_cond = IA32_JAE;
1474 break;
1475 case BPF_JSLE:
1476 if (!is_cmp_lo)
1477 /* Signed '<=', LE in x86 */
1478 jmp_cond = IA32_JLE;
1479 else
1480 /* LE is unsigned '<=', JBE in x86 */
1481 jmp_cond = IA32_JBE;
1482 break;
1483 default: /* to silence GCC warning */
1484 jmp_cond = COND_JMP_OPCODE_INVALID;
1485 break;
1486 }
1487
1488 return jmp_cond;
1489 }
1490
1491 /* i386 kernel compiles with "-mregparm=3". From gcc document:
1492 *
1493 * ==== snippet ====
1494 * regparm (number)
1495 * On x86-32 targets, the regparm attribute causes the compiler
1496 * to pass arguments number one to (number) if they are of integral
1497 * type in registers EAX, EDX, and ECX instead of on the stack.
1498 * Functions that take a variable number of arguments continue
1499 * to be passed all of their arguments on the stack.
1500 * ==== snippet ====
1501 *
1502 * The first three args of a function will be considered for
1503 * putting into the 32bit register EAX, EDX, and ECX.
1504 *
1505 * Two 32bit registers are used to pass a 64bit arg.
1506 *
1507 * For example,
1508 * void foo(u32 a, u32 b, u32 c, u32 d):
1509 * u32 a: EAX
1510 * u32 b: EDX
1511 * u32 c: ECX
1512 * u32 d: stack
1513 *
1514 * void foo(u64 a, u32 b, u32 c):
1515 * u64 a: EAX (lo32) EDX (hi32)
1516 * u32 b: ECX
1517 * u32 c: stack
1518 *
1519 * void foo(u32 a, u64 b, u32 c):
1520 * u32 a: EAX
1521 * u64 b: EDX (lo32) ECX (hi32)
1522 * u32 c: stack
1523 *
1524 * void foo(u32 a, u32 b, u64 c):
1525 * u32 a: EAX
1526 * u32 b: EDX
1527 * u64 c: stack
1528 *
1529 * The return value will be stored in the EAX (and EDX for 64bit value).
1530 *
1531 * For example,
1532 * u32 foo(u32 a, u32 b, u32 c):
1533 * return value: EAX
1534 *
1535 * u64 foo(u32 a, u32 b, u32 c):
1536 * return value: EAX (lo32) EDX (hi32)
1537 *
1538 * Notes:
1539 * The verifier only accepts function having integer and pointers
1540 * as its args and return value, so it does not have
1541 * struct-by-value.
1542 *
1543 * emit_kfunc_call() finds out the btf_func_model by calling
1544 * bpf_jit_find_kfunc_model(). A btf_func_model
1545 * has the details about the number of args, size of each arg,
1546 * and the size of the return value.
1547 *
1548 * It first decides how many args can be passed by EAX, EDX, and ECX.
1549 * That will decide what args should be pushed to the stack:
1550 * [first_stack_regno, last_stack_regno] are the bpf regnos
1551 * that should be pushed to the stack.
1552 *
1553 * It will first push all args to the stack because the push
1554 * will need to use ECX. Then, it moves
1555 * [BPF_REG_1, first_stack_regno) to EAX, EDX, and ECX.
1556 *
1557 * When emitting a call (0xE8), it needs to figure out
1558 * the jmp_offset relative to the jit-insn address immediately
1559 * following the call (0xE8) instruction. At this point, it knows
1560 * the end of the jit-insn address after completely translated the
1561 * current (BPF_JMP | BPF_CALL) bpf-insn. It is passed as "end_addr"
1562 * to the emit_kfunc_call(). Thus, it can learn the "immediate-follow-call"
1563 * address by figuring out how many jit-insn is generated between
1564 * the call (0xE8) and the end_addr:
1565 * - 0-1 jit-insn (3 bytes each) to restore the esp pointer if there
1566 * is arg pushed to the stack.
1567 * - 0-2 jit-insns (3 bytes each) to handle the return value.
1568 */
emit_kfunc_call(const struct bpf_prog * bpf_prog,u8 * end_addr,const struct bpf_insn * insn,u8 ** pprog)1569 static int emit_kfunc_call(const struct bpf_prog *bpf_prog, u8 *end_addr,
1570 const struct bpf_insn *insn, u8 **pprog)
1571 {
1572 const u8 arg_regs[] = { IA32_EAX, IA32_EDX, IA32_ECX };
1573 int i, cnt = 0, first_stack_regno, last_stack_regno;
1574 int free_arg_regs = ARRAY_SIZE(arg_regs);
1575 const struct btf_func_model *fm;
1576 int bytes_in_stack = 0;
1577 const u8 *cur_arg_reg;
1578 u8 *prog = *pprog;
1579 s64 jmp_offset;
1580
1581 fm = bpf_jit_find_kfunc_model(bpf_prog, insn);
1582 if (!fm)
1583 return -EINVAL;
1584
1585 first_stack_regno = BPF_REG_1;
1586 for (i = 0; i < fm->nr_args; i++) {
1587 int regs_needed = fm->arg_size[i] > sizeof(u32) ? 2 : 1;
1588
1589 if (regs_needed > free_arg_regs)
1590 break;
1591
1592 free_arg_regs -= regs_needed;
1593 first_stack_regno++;
1594 }
1595
1596 /* Push the args to the stack */
1597 last_stack_regno = BPF_REG_0 + fm->nr_args;
1598 for (i = last_stack_regno; i >= first_stack_regno; i--) {
1599 if (fm->arg_size[i - 1] > sizeof(u32)) {
1600 emit_push_r64(bpf2ia32[i], &prog);
1601 bytes_in_stack += 8;
1602 } else {
1603 emit_push_r32(bpf2ia32[i], &prog);
1604 bytes_in_stack += 4;
1605 }
1606 }
1607
1608 cur_arg_reg = &arg_regs[0];
1609 for (i = BPF_REG_1; i < first_stack_regno; i++) {
1610 /* mov e[adc]x,dword ptr [ebp+off] */
1611 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, *cur_arg_reg++),
1612 STACK_VAR(bpf2ia32[i][0]));
1613 if (fm->arg_size[i - 1] > sizeof(u32))
1614 /* mov e[adc]x,dword ptr [ebp+off] */
1615 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, *cur_arg_reg++),
1616 STACK_VAR(bpf2ia32[i][1]));
1617 }
1618
1619 if (bytes_in_stack)
1620 /* add esp,"bytes_in_stack" */
1621 end_addr -= 3;
1622
1623 /* mov dword ptr [ebp+off],edx */
1624 if (fm->ret_size > sizeof(u32))
1625 end_addr -= 3;
1626
1627 /* mov dword ptr [ebp+off],eax */
1628 if (fm->ret_size)
1629 end_addr -= 3;
1630
1631 jmp_offset = (u8 *)__bpf_call_base + insn->imm - end_addr;
1632 if (!is_simm32(jmp_offset)) {
1633 pr_err("unsupported BPF kernel function jmp_offset:%lld\n",
1634 jmp_offset);
1635 return -EINVAL;
1636 }
1637
1638 EMIT1_off32(0xE8, jmp_offset);
1639
1640 if (fm->ret_size)
1641 /* mov dword ptr [ebp+off],eax */
1642 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
1643 STACK_VAR(bpf2ia32[BPF_REG_0][0]));
1644
1645 if (fm->ret_size > sizeof(u32))
1646 /* mov dword ptr [ebp+off],edx */
1647 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
1648 STACK_VAR(bpf2ia32[BPF_REG_0][1]));
1649
1650 if (bytes_in_stack)
1651 /* add esp,"bytes_in_stack" */
1652 EMIT3(0x83, add_1reg(0xC0, IA32_ESP), bytes_in_stack);
1653
1654 *pprog = prog;
1655
1656 return 0;
1657 }
1658
do_jit(struct bpf_prog * bpf_prog,int * addrs,u8 * image,int oldproglen,struct jit_context * ctx)1659 static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
1660 int oldproglen, struct jit_context *ctx)
1661 {
1662 struct bpf_insn *insn = bpf_prog->insnsi;
1663 int insn_cnt = bpf_prog->len;
1664 bool seen_exit = false;
1665 u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
1666 int i, cnt = 0;
1667 int proglen = 0;
1668 u8 *prog = temp;
1669
1670 emit_prologue(&prog, bpf_prog->aux->stack_depth);
1671
1672 for (i = 0; i < insn_cnt; i++, insn++) {
1673 const s32 imm32 = insn->imm;
1674 const bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
1675 const bool dstk = insn->dst_reg != BPF_REG_AX;
1676 const bool sstk = insn->src_reg != BPF_REG_AX;
1677 const u8 code = insn->code;
1678 const u8 *dst = bpf2ia32[insn->dst_reg];
1679 const u8 *src = bpf2ia32[insn->src_reg];
1680 const u8 *r0 = bpf2ia32[BPF_REG_0];
1681 s64 jmp_offset;
1682 u8 jmp_cond;
1683 int ilen;
1684 u8 *func;
1685
1686 switch (code) {
1687 /* ALU operations */
1688 /* dst = src */
1689 case BPF_ALU | BPF_MOV | BPF_K:
1690 case BPF_ALU | BPF_MOV | BPF_X:
1691 case BPF_ALU64 | BPF_MOV | BPF_K:
1692 case BPF_ALU64 | BPF_MOV | BPF_X:
1693 switch (BPF_SRC(code)) {
1694 case BPF_X:
1695 if (imm32 == 1) {
1696 /* Special mov32 for zext. */
1697 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1698 break;
1699 }
1700 emit_ia32_mov_r64(is64, dst, src, dstk, sstk,
1701 &prog, bpf_prog->aux);
1702 break;
1703 case BPF_K:
1704 /* Sign-extend immediate value to dst reg */
1705 emit_ia32_mov_i64(is64, dst, imm32,
1706 dstk, &prog);
1707 break;
1708 }
1709 break;
1710 /* dst = dst + src/imm */
1711 /* dst = dst - src/imm */
1712 /* dst = dst | src/imm */
1713 /* dst = dst & src/imm */
1714 /* dst = dst ^ src/imm */
1715 /* dst = dst * src/imm */
1716 /* dst = dst << src */
1717 /* dst = dst >> src */
1718 case BPF_ALU | BPF_ADD | BPF_K:
1719 case BPF_ALU | BPF_ADD | BPF_X:
1720 case BPF_ALU | BPF_SUB | BPF_K:
1721 case BPF_ALU | BPF_SUB | BPF_X:
1722 case BPF_ALU | BPF_OR | BPF_K:
1723 case BPF_ALU | BPF_OR | BPF_X:
1724 case BPF_ALU | BPF_AND | BPF_K:
1725 case BPF_ALU | BPF_AND | BPF_X:
1726 case BPF_ALU | BPF_XOR | BPF_K:
1727 case BPF_ALU | BPF_XOR | BPF_X:
1728 case BPF_ALU64 | BPF_ADD | BPF_K:
1729 case BPF_ALU64 | BPF_ADD | BPF_X:
1730 case BPF_ALU64 | BPF_SUB | BPF_K:
1731 case BPF_ALU64 | BPF_SUB | BPF_X:
1732 case BPF_ALU64 | BPF_OR | BPF_K:
1733 case BPF_ALU64 | BPF_OR | BPF_X:
1734 case BPF_ALU64 | BPF_AND | BPF_K:
1735 case BPF_ALU64 | BPF_AND | BPF_X:
1736 case BPF_ALU64 | BPF_XOR | BPF_K:
1737 case BPF_ALU64 | BPF_XOR | BPF_X:
1738 switch (BPF_SRC(code)) {
1739 case BPF_X:
1740 emit_ia32_alu_r64(is64, BPF_OP(code), dst,
1741 src, dstk, sstk, &prog,
1742 bpf_prog->aux);
1743 break;
1744 case BPF_K:
1745 emit_ia32_alu_i64(is64, BPF_OP(code), dst,
1746 imm32, dstk, &prog,
1747 bpf_prog->aux);
1748 break;
1749 }
1750 break;
1751 case BPF_ALU | BPF_MUL | BPF_K:
1752 case BPF_ALU | BPF_MUL | BPF_X:
1753 switch (BPF_SRC(code)) {
1754 case BPF_X:
1755 emit_ia32_mul_r(dst_lo, src_lo, dstk,
1756 sstk, &prog);
1757 break;
1758 case BPF_K:
1759 /* mov ecx,imm32*/
1760 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1761 imm32);
1762 emit_ia32_mul_r(dst_lo, IA32_ECX, dstk,
1763 false, &prog);
1764 break;
1765 }
1766 if (!bpf_prog->aux->verifier_zext)
1767 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1768 break;
1769 case BPF_ALU | BPF_LSH | BPF_X:
1770 case BPF_ALU | BPF_RSH | BPF_X:
1771 case BPF_ALU | BPF_ARSH | BPF_K:
1772 case BPF_ALU | BPF_ARSH | BPF_X:
1773 switch (BPF_SRC(code)) {
1774 case BPF_X:
1775 emit_ia32_shift_r(BPF_OP(code), dst_lo, src_lo,
1776 dstk, sstk, &prog);
1777 break;
1778 case BPF_K:
1779 /* mov ecx,imm32*/
1780 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1781 imm32);
1782 emit_ia32_shift_r(BPF_OP(code), dst_lo,
1783 IA32_ECX, dstk, false,
1784 &prog);
1785 break;
1786 }
1787 if (!bpf_prog->aux->verifier_zext)
1788 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1789 break;
1790 /* dst = dst / src(imm) */
1791 /* dst = dst % src(imm) */
1792 case BPF_ALU | BPF_DIV | BPF_K:
1793 case BPF_ALU | BPF_DIV | BPF_X:
1794 case BPF_ALU | BPF_MOD | BPF_K:
1795 case BPF_ALU | BPF_MOD | BPF_X:
1796 switch (BPF_SRC(code)) {
1797 case BPF_X:
1798 emit_ia32_div_mod_r(BPF_OP(code), dst_lo,
1799 src_lo, dstk, sstk, &prog);
1800 break;
1801 case BPF_K:
1802 /* mov ecx,imm32*/
1803 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX),
1804 imm32);
1805 emit_ia32_div_mod_r(BPF_OP(code), dst_lo,
1806 IA32_ECX, dstk, false,
1807 &prog);
1808 break;
1809 }
1810 if (!bpf_prog->aux->verifier_zext)
1811 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1812 break;
1813 case BPF_ALU64 | BPF_DIV | BPF_K:
1814 case BPF_ALU64 | BPF_DIV | BPF_X:
1815 case BPF_ALU64 | BPF_MOD | BPF_K:
1816 case BPF_ALU64 | BPF_MOD | BPF_X:
1817 goto notyet;
1818 /* dst = dst >> imm */
1819 /* dst = dst << imm */
1820 case BPF_ALU | BPF_RSH | BPF_K:
1821 case BPF_ALU | BPF_LSH | BPF_K:
1822 if (unlikely(imm32 > 31))
1823 return -EINVAL;
1824 /* mov ecx,imm32*/
1825 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
1826 emit_ia32_shift_r(BPF_OP(code), dst_lo, IA32_ECX, dstk,
1827 false, &prog);
1828 if (!bpf_prog->aux->verifier_zext)
1829 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1830 break;
1831 /* dst = dst << imm */
1832 case BPF_ALU64 | BPF_LSH | BPF_K:
1833 if (unlikely(imm32 > 63))
1834 return -EINVAL;
1835 emit_ia32_lsh_i64(dst, imm32, dstk, &prog);
1836 break;
1837 /* dst = dst >> imm */
1838 case BPF_ALU64 | BPF_RSH | BPF_K:
1839 if (unlikely(imm32 > 63))
1840 return -EINVAL;
1841 emit_ia32_rsh_i64(dst, imm32, dstk, &prog);
1842 break;
1843 /* dst = dst << src */
1844 case BPF_ALU64 | BPF_LSH | BPF_X:
1845 emit_ia32_lsh_r64(dst, src, dstk, sstk, &prog);
1846 break;
1847 /* dst = dst >> src */
1848 case BPF_ALU64 | BPF_RSH | BPF_X:
1849 emit_ia32_rsh_r64(dst, src, dstk, sstk, &prog);
1850 break;
1851 /* dst = dst >> src (signed) */
1852 case BPF_ALU64 | BPF_ARSH | BPF_X:
1853 emit_ia32_arsh_r64(dst, src, dstk, sstk, &prog);
1854 break;
1855 /* dst = dst >> imm (signed) */
1856 case BPF_ALU64 | BPF_ARSH | BPF_K:
1857 if (unlikely(imm32 > 63))
1858 return -EINVAL;
1859 emit_ia32_arsh_i64(dst, imm32, dstk, &prog);
1860 break;
1861 /* dst = ~dst */
1862 case BPF_ALU | BPF_NEG:
1863 emit_ia32_alu_i(is64, false, BPF_OP(code),
1864 dst_lo, 0, dstk, &prog);
1865 if (!bpf_prog->aux->verifier_zext)
1866 emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
1867 break;
1868 /* dst = ~dst (64 bit) */
1869 case BPF_ALU64 | BPF_NEG:
1870 emit_ia32_neg64(dst, dstk, &prog);
1871 break;
1872 /* dst = dst * src/imm */
1873 case BPF_ALU64 | BPF_MUL | BPF_X:
1874 case BPF_ALU64 | BPF_MUL | BPF_K:
1875 switch (BPF_SRC(code)) {
1876 case BPF_X:
1877 emit_ia32_mul_r64(dst, src, dstk, sstk, &prog);
1878 break;
1879 case BPF_K:
1880 emit_ia32_mul_i64(dst, imm32, dstk, &prog);
1881 break;
1882 }
1883 break;
1884 /* dst = htole(dst) */
1885 case BPF_ALU | BPF_END | BPF_FROM_LE:
1886 emit_ia32_to_le_r64(dst, imm32, dstk, &prog,
1887 bpf_prog->aux);
1888 break;
1889 /* dst = htobe(dst) */
1890 case BPF_ALU | BPF_END | BPF_FROM_BE:
1891 emit_ia32_to_be_r64(dst, imm32, dstk, &prog,
1892 bpf_prog->aux);
1893 break;
1894 /* dst = imm64 */
1895 case BPF_LD | BPF_IMM | BPF_DW: {
1896 s32 hi, lo = imm32;
1897
1898 hi = insn[1].imm;
1899 emit_ia32_mov_i(dst_lo, lo, dstk, &prog);
1900 emit_ia32_mov_i(dst_hi, hi, dstk, &prog);
1901 insn++;
1902 i++;
1903 break;
1904 }
1905 /* speculation barrier */
1906 case BPF_ST | BPF_NOSPEC:
1907 if (boot_cpu_has(X86_FEATURE_XMM2))
1908 /* Emit 'lfence' */
1909 EMIT3(0x0F, 0xAE, 0xE8);
1910 break;
1911 /* ST: *(u8*)(dst_reg + off) = imm */
1912 case BPF_ST | BPF_MEM | BPF_H:
1913 case BPF_ST | BPF_MEM | BPF_B:
1914 case BPF_ST | BPF_MEM | BPF_W:
1915 case BPF_ST | BPF_MEM | BPF_DW:
1916 if (dstk)
1917 /* mov eax,dword ptr [ebp+off] */
1918 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1919 STACK_VAR(dst_lo));
1920 else
1921 /* mov eax,dst_lo */
1922 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1923
1924 switch (BPF_SIZE(code)) {
1925 case BPF_B:
1926 EMIT(0xC6, 1); break;
1927 case BPF_H:
1928 EMIT2(0x66, 0xC7); break;
1929 case BPF_W:
1930 case BPF_DW:
1931 EMIT(0xC7, 1); break;
1932 }
1933
1934 if (is_imm8(insn->off))
1935 EMIT2(add_1reg(0x40, IA32_EAX), insn->off);
1936 else
1937 EMIT1_off32(add_1reg(0x80, IA32_EAX),
1938 insn->off);
1939 EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(code)));
1940
1941 if (BPF_SIZE(code) == BPF_DW) {
1942 u32 hi;
1943
1944 hi = imm32 & (1<<31) ? (u32)~0 : 0;
1945 EMIT2_off32(0xC7, add_1reg(0x80, IA32_EAX),
1946 insn->off + 4);
1947 EMIT(hi, 4);
1948 }
1949 break;
1950
1951 /* STX: *(u8*)(dst_reg + off) = src_reg */
1952 case BPF_STX | BPF_MEM | BPF_B:
1953 case BPF_STX | BPF_MEM | BPF_H:
1954 case BPF_STX | BPF_MEM | BPF_W:
1955 case BPF_STX | BPF_MEM | BPF_DW:
1956 if (dstk)
1957 /* mov eax,dword ptr [ebp+off] */
1958 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
1959 STACK_VAR(dst_lo));
1960 else
1961 /* mov eax,dst_lo */
1962 EMIT2(0x8B, add_2reg(0xC0, dst_lo, IA32_EAX));
1963
1964 if (sstk)
1965 /* mov edx,dword ptr [ebp+off] */
1966 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
1967 STACK_VAR(src_lo));
1968 else
1969 /* mov edx,src_lo */
1970 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_EDX));
1971
1972 switch (BPF_SIZE(code)) {
1973 case BPF_B:
1974 EMIT(0x88, 1); break;
1975 case BPF_H:
1976 EMIT2(0x66, 0x89); break;
1977 case BPF_W:
1978 case BPF_DW:
1979 EMIT(0x89, 1); break;
1980 }
1981
1982 if (is_imm8(insn->off))
1983 EMIT2(add_2reg(0x40, IA32_EAX, IA32_EDX),
1984 insn->off);
1985 else
1986 EMIT1_off32(add_2reg(0x80, IA32_EAX, IA32_EDX),
1987 insn->off);
1988
1989 if (BPF_SIZE(code) == BPF_DW) {
1990 if (sstk)
1991 /* mov edi,dword ptr [ebp+off] */
1992 EMIT3(0x8B, add_2reg(0x40, IA32_EBP,
1993 IA32_EDX),
1994 STACK_VAR(src_hi));
1995 else
1996 /* mov edi,src_hi */
1997 EMIT2(0x8B, add_2reg(0xC0, src_hi,
1998 IA32_EDX));
1999 EMIT1(0x89);
2000 if (is_imm8(insn->off + 4)) {
2001 EMIT2(add_2reg(0x40, IA32_EAX,
2002 IA32_EDX),
2003 insn->off + 4);
2004 } else {
2005 EMIT1(add_2reg(0x80, IA32_EAX,
2006 IA32_EDX));
2007 EMIT(insn->off + 4, 4);
2008 }
2009 }
2010 break;
2011
2012 /* LDX: dst_reg = *(u8*)(src_reg + off) */
2013 case BPF_LDX | BPF_MEM | BPF_B:
2014 case BPF_LDX | BPF_MEM | BPF_H:
2015 case BPF_LDX | BPF_MEM | BPF_W:
2016 case BPF_LDX | BPF_MEM | BPF_DW:
2017 if (sstk)
2018 /* mov eax,dword ptr [ebp+off] */
2019 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2020 STACK_VAR(src_lo));
2021 else
2022 /* mov eax,dword ptr [ebp+off] */
2023 EMIT2(0x8B, add_2reg(0xC0, src_lo, IA32_EAX));
2024
2025 switch (BPF_SIZE(code)) {
2026 case BPF_B:
2027 EMIT2(0x0F, 0xB6); break;
2028 case BPF_H:
2029 EMIT2(0x0F, 0xB7); break;
2030 case BPF_W:
2031 case BPF_DW:
2032 EMIT(0x8B, 1); break;
2033 }
2034
2035 if (is_imm8(insn->off))
2036 EMIT2(add_2reg(0x40, IA32_EAX, IA32_EDX),
2037 insn->off);
2038 else
2039 EMIT1_off32(add_2reg(0x80, IA32_EAX, IA32_EDX),
2040 insn->off);
2041
2042 if (dstk)
2043 /* mov dword ptr [ebp+off],edx */
2044 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
2045 STACK_VAR(dst_lo));
2046 else
2047 /* mov dst_lo,edx */
2048 EMIT2(0x89, add_2reg(0xC0, dst_lo, IA32_EDX));
2049 switch (BPF_SIZE(code)) {
2050 case BPF_B:
2051 case BPF_H:
2052 case BPF_W:
2053 if (bpf_prog->aux->verifier_zext)
2054 break;
2055 if (dstk) {
2056 EMIT3(0xC7, add_1reg(0x40, IA32_EBP),
2057 STACK_VAR(dst_hi));
2058 EMIT(0x0, 4);
2059 } else {
2060 /* xor dst_hi,dst_hi */
2061 EMIT2(0x33,
2062 add_2reg(0xC0, dst_hi, dst_hi));
2063 }
2064 break;
2065 case BPF_DW:
2066 EMIT2_off32(0x8B,
2067 add_2reg(0x80, IA32_EAX, IA32_EDX),
2068 insn->off + 4);
2069 if (dstk)
2070 EMIT3(0x89,
2071 add_2reg(0x40, IA32_EBP,
2072 IA32_EDX),
2073 STACK_VAR(dst_hi));
2074 else
2075 EMIT2(0x89,
2076 add_2reg(0xC0, dst_hi, IA32_EDX));
2077 break;
2078 default:
2079 break;
2080 }
2081 break;
2082 /* call */
2083 case BPF_JMP | BPF_CALL:
2084 {
2085 const u8 *r1 = bpf2ia32[BPF_REG_1];
2086 const u8 *r2 = bpf2ia32[BPF_REG_2];
2087 const u8 *r3 = bpf2ia32[BPF_REG_3];
2088 const u8 *r4 = bpf2ia32[BPF_REG_4];
2089 const u8 *r5 = bpf2ia32[BPF_REG_5];
2090
2091 if (insn->src_reg == BPF_PSEUDO_CALL)
2092 goto notyet;
2093
2094 if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
2095 int err;
2096
2097 err = emit_kfunc_call(bpf_prog,
2098 image + addrs[i],
2099 insn, &prog);
2100
2101 if (err)
2102 return err;
2103 break;
2104 }
2105
2106 func = (u8 *) __bpf_call_base + imm32;
2107 jmp_offset = func - (image + addrs[i]);
2108
2109 if (!imm32 || !is_simm32(jmp_offset)) {
2110 pr_err("unsupported BPF func %d addr %p image %p\n",
2111 imm32, func, image);
2112 return -EINVAL;
2113 }
2114
2115 /* mov eax,dword ptr [ebp+off] */
2116 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2117 STACK_VAR(r1[0]));
2118 /* mov edx,dword ptr [ebp+off] */
2119 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EDX),
2120 STACK_VAR(r1[1]));
2121
2122 emit_push_r64(r5, &prog);
2123 emit_push_r64(r4, &prog);
2124 emit_push_r64(r3, &prog);
2125 emit_push_r64(r2, &prog);
2126
2127 EMIT1_off32(0xE8, jmp_offset + 9);
2128
2129 /* mov dword ptr [ebp+off],eax */
2130 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EAX),
2131 STACK_VAR(r0[0]));
2132 /* mov dword ptr [ebp+off],edx */
2133 EMIT3(0x89, add_2reg(0x40, IA32_EBP, IA32_EDX),
2134 STACK_VAR(r0[1]));
2135
2136 /* add esp,32 */
2137 EMIT3(0x83, add_1reg(0xC0, IA32_ESP), 32);
2138 break;
2139 }
2140 case BPF_JMP | BPF_TAIL_CALL:
2141 emit_bpf_tail_call(&prog, image + addrs[i - 1]);
2142 break;
2143
2144 /* cond jump */
2145 case BPF_JMP | BPF_JEQ | BPF_X:
2146 case BPF_JMP | BPF_JNE | BPF_X:
2147 case BPF_JMP | BPF_JGT | BPF_X:
2148 case BPF_JMP | BPF_JLT | BPF_X:
2149 case BPF_JMP | BPF_JGE | BPF_X:
2150 case BPF_JMP | BPF_JLE | BPF_X:
2151 case BPF_JMP32 | BPF_JEQ | BPF_X:
2152 case BPF_JMP32 | BPF_JNE | BPF_X:
2153 case BPF_JMP32 | BPF_JGT | BPF_X:
2154 case BPF_JMP32 | BPF_JLT | BPF_X:
2155 case BPF_JMP32 | BPF_JGE | BPF_X:
2156 case BPF_JMP32 | BPF_JLE | BPF_X:
2157 case BPF_JMP32 | BPF_JSGT | BPF_X:
2158 case BPF_JMP32 | BPF_JSLE | BPF_X:
2159 case BPF_JMP32 | BPF_JSLT | BPF_X:
2160 case BPF_JMP32 | BPF_JSGE | BPF_X: {
2161 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2162 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2163 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2164 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
2165 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
2166
2167 if (dstk) {
2168 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2169 STACK_VAR(dst_lo));
2170 if (is_jmp64)
2171 EMIT3(0x8B,
2172 add_2reg(0x40, IA32_EBP,
2173 IA32_EDX),
2174 STACK_VAR(dst_hi));
2175 }
2176
2177 if (sstk) {
2178 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
2179 STACK_VAR(src_lo));
2180 if (is_jmp64)
2181 EMIT3(0x8B,
2182 add_2reg(0x40, IA32_EBP,
2183 IA32_EBX),
2184 STACK_VAR(src_hi));
2185 }
2186
2187 if (is_jmp64) {
2188 /* cmp dreg_hi,sreg_hi */
2189 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2190 EMIT2(IA32_JNE, 2);
2191 }
2192 /* cmp dreg_lo,sreg_lo */
2193 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2194 goto emit_cond_jmp;
2195 }
2196 case BPF_JMP | BPF_JSGT | BPF_X:
2197 case BPF_JMP | BPF_JSLE | BPF_X:
2198 case BPF_JMP | BPF_JSLT | BPF_X:
2199 case BPF_JMP | BPF_JSGE | BPF_X: {
2200 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2201 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2202 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
2203 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
2204
2205 if (dstk) {
2206 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2207 STACK_VAR(dst_lo));
2208 EMIT3(0x8B,
2209 add_2reg(0x40, IA32_EBP,
2210 IA32_EDX),
2211 STACK_VAR(dst_hi));
2212 }
2213
2214 if (sstk) {
2215 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
2216 STACK_VAR(src_lo));
2217 EMIT3(0x8B,
2218 add_2reg(0x40, IA32_EBP,
2219 IA32_EBX),
2220 STACK_VAR(src_hi));
2221 }
2222
2223 /* cmp dreg_hi,sreg_hi */
2224 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2225 EMIT2(IA32_JNE, 10);
2226 /* cmp dreg_lo,sreg_lo */
2227 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2228 goto emit_cond_jmp_signed;
2229 }
2230 case BPF_JMP | BPF_JSET | BPF_X:
2231 case BPF_JMP32 | BPF_JSET | BPF_X: {
2232 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2233 u8 dreg_lo = IA32_EAX;
2234 u8 dreg_hi = IA32_EDX;
2235 u8 sreg_lo = sstk ? IA32_ECX : src_lo;
2236 u8 sreg_hi = sstk ? IA32_EBX : src_hi;
2237
2238 if (dstk) {
2239 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2240 STACK_VAR(dst_lo));
2241 if (is_jmp64)
2242 EMIT3(0x8B,
2243 add_2reg(0x40, IA32_EBP,
2244 IA32_EDX),
2245 STACK_VAR(dst_hi));
2246 } else {
2247 /* mov dreg_lo,dst_lo */
2248 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dst_lo));
2249 if (is_jmp64)
2250 /* mov dreg_hi,dst_hi */
2251 EMIT2(0x89,
2252 add_2reg(0xC0, dreg_hi, dst_hi));
2253 }
2254
2255 if (sstk) {
2256 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_ECX),
2257 STACK_VAR(src_lo));
2258 if (is_jmp64)
2259 EMIT3(0x8B,
2260 add_2reg(0x40, IA32_EBP,
2261 IA32_EBX),
2262 STACK_VAR(src_hi));
2263 }
2264 /* and dreg_lo,sreg_lo */
2265 EMIT2(0x23, add_2reg(0xC0, sreg_lo, dreg_lo));
2266 if (is_jmp64) {
2267 /* and dreg_hi,sreg_hi */
2268 EMIT2(0x23, add_2reg(0xC0, sreg_hi, dreg_hi));
2269 /* or dreg_lo,dreg_hi */
2270 EMIT2(0x09, add_2reg(0xC0, dreg_lo, dreg_hi));
2271 }
2272 goto emit_cond_jmp;
2273 }
2274 case BPF_JMP | BPF_JSET | BPF_K:
2275 case BPF_JMP32 | BPF_JSET | BPF_K: {
2276 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2277 u8 dreg_lo = IA32_EAX;
2278 u8 dreg_hi = IA32_EDX;
2279 u8 sreg_lo = IA32_ECX;
2280 u8 sreg_hi = IA32_EBX;
2281 u32 hi;
2282
2283 if (dstk) {
2284 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2285 STACK_VAR(dst_lo));
2286 if (is_jmp64)
2287 EMIT3(0x8B,
2288 add_2reg(0x40, IA32_EBP,
2289 IA32_EDX),
2290 STACK_VAR(dst_hi));
2291 } else {
2292 /* mov dreg_lo,dst_lo */
2293 EMIT2(0x89, add_2reg(0xC0, dreg_lo, dst_lo));
2294 if (is_jmp64)
2295 /* mov dreg_hi,dst_hi */
2296 EMIT2(0x89,
2297 add_2reg(0xC0, dreg_hi, dst_hi));
2298 }
2299
2300 /* mov ecx,imm32 */
2301 EMIT2_off32(0xC7, add_1reg(0xC0, sreg_lo), imm32);
2302
2303 /* and dreg_lo,sreg_lo */
2304 EMIT2(0x23, add_2reg(0xC0, sreg_lo, dreg_lo));
2305 if (is_jmp64) {
2306 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2307 /* mov ebx,imm32 */
2308 EMIT2_off32(0xC7, add_1reg(0xC0, sreg_hi), hi);
2309 /* and dreg_hi,sreg_hi */
2310 EMIT2(0x23, add_2reg(0xC0, sreg_hi, dreg_hi));
2311 /* or dreg_lo,dreg_hi */
2312 EMIT2(0x09, add_2reg(0xC0, dreg_lo, dreg_hi));
2313 }
2314 goto emit_cond_jmp;
2315 }
2316 case BPF_JMP | BPF_JEQ | BPF_K:
2317 case BPF_JMP | BPF_JNE | BPF_K:
2318 case BPF_JMP | BPF_JGT | BPF_K:
2319 case BPF_JMP | BPF_JLT | BPF_K:
2320 case BPF_JMP | BPF_JGE | BPF_K:
2321 case BPF_JMP | BPF_JLE | BPF_K:
2322 case BPF_JMP32 | BPF_JEQ | BPF_K:
2323 case BPF_JMP32 | BPF_JNE | BPF_K:
2324 case BPF_JMP32 | BPF_JGT | BPF_K:
2325 case BPF_JMP32 | BPF_JLT | BPF_K:
2326 case BPF_JMP32 | BPF_JGE | BPF_K:
2327 case BPF_JMP32 | BPF_JLE | BPF_K:
2328 case BPF_JMP32 | BPF_JSGT | BPF_K:
2329 case BPF_JMP32 | BPF_JSLE | BPF_K:
2330 case BPF_JMP32 | BPF_JSLT | BPF_K:
2331 case BPF_JMP32 | BPF_JSGE | BPF_K: {
2332 bool is_jmp64 = BPF_CLASS(insn->code) == BPF_JMP;
2333 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2334 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2335 u8 sreg_lo = IA32_ECX;
2336 u8 sreg_hi = IA32_EBX;
2337 u32 hi;
2338
2339 if (dstk) {
2340 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2341 STACK_VAR(dst_lo));
2342 if (is_jmp64)
2343 EMIT3(0x8B,
2344 add_2reg(0x40, IA32_EBP,
2345 IA32_EDX),
2346 STACK_VAR(dst_hi));
2347 }
2348
2349 /* mov ecx,imm32 */
2350 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
2351 if (is_jmp64) {
2352 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2353 /* mov ebx,imm32 */
2354 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EBX), hi);
2355 /* cmp dreg_hi,sreg_hi */
2356 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2357 EMIT2(IA32_JNE, 2);
2358 }
2359 /* cmp dreg_lo,sreg_lo */
2360 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2361
2362 emit_cond_jmp: jmp_cond = get_cond_jmp_opcode(BPF_OP(code), false);
2363 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2364 return -EFAULT;
2365 jmp_offset = addrs[i + insn->off] - addrs[i];
2366 if (is_imm8(jmp_offset)) {
2367 EMIT2(jmp_cond, jmp_offset);
2368 } else if (is_simm32(jmp_offset)) {
2369 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2370 } else {
2371 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2372 return -EFAULT;
2373 }
2374 break;
2375 }
2376 case BPF_JMP | BPF_JSGT | BPF_K:
2377 case BPF_JMP | BPF_JSLE | BPF_K:
2378 case BPF_JMP | BPF_JSLT | BPF_K:
2379 case BPF_JMP | BPF_JSGE | BPF_K: {
2380 u8 dreg_lo = dstk ? IA32_EAX : dst_lo;
2381 u8 dreg_hi = dstk ? IA32_EDX : dst_hi;
2382 u8 sreg_lo = IA32_ECX;
2383 u8 sreg_hi = IA32_EBX;
2384 u32 hi;
2385
2386 if (dstk) {
2387 EMIT3(0x8B, add_2reg(0x40, IA32_EBP, IA32_EAX),
2388 STACK_VAR(dst_lo));
2389 EMIT3(0x8B,
2390 add_2reg(0x40, IA32_EBP,
2391 IA32_EDX),
2392 STACK_VAR(dst_hi));
2393 }
2394
2395 /* mov ecx,imm32 */
2396 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
2397 hi = imm32 & (1 << 31) ? (u32)~0 : 0;
2398 /* mov ebx,imm32 */
2399 EMIT2_off32(0xC7, add_1reg(0xC0, IA32_EBX), hi);
2400 /* cmp dreg_hi,sreg_hi */
2401 EMIT2(0x39, add_2reg(0xC0, dreg_hi, sreg_hi));
2402 EMIT2(IA32_JNE, 10);
2403 /* cmp dreg_lo,sreg_lo */
2404 EMIT2(0x39, add_2reg(0xC0, dreg_lo, sreg_lo));
2405
2406 /*
2407 * For simplicity of branch offset computation,
2408 * let's use fixed jump coding here.
2409 */
2410 emit_cond_jmp_signed: /* Check the condition for low 32-bit comparison */
2411 jmp_cond = get_cond_jmp_opcode(BPF_OP(code), true);
2412 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2413 return -EFAULT;
2414 jmp_offset = addrs[i + insn->off] - addrs[i] + 8;
2415 if (is_simm32(jmp_offset)) {
2416 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2417 } else {
2418 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2419 return -EFAULT;
2420 }
2421 EMIT2(0xEB, 6);
2422
2423 /* Check the condition for high 32-bit comparison */
2424 jmp_cond = get_cond_jmp_opcode(BPF_OP(code), false);
2425 if (jmp_cond == COND_JMP_OPCODE_INVALID)
2426 return -EFAULT;
2427 jmp_offset = addrs[i + insn->off] - addrs[i];
2428 if (is_simm32(jmp_offset)) {
2429 EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
2430 } else {
2431 pr_err("cond_jmp gen bug %llx\n", jmp_offset);
2432 return -EFAULT;
2433 }
2434 break;
2435 }
2436 case BPF_JMP | BPF_JA:
2437 if (insn->off == -1)
2438 /* -1 jmp instructions will always jump
2439 * backwards two bytes. Explicitly handling
2440 * this case avoids wasting too many passes
2441 * when there are long sequences of replaced
2442 * dead code.
2443 */
2444 jmp_offset = -2;
2445 else
2446 jmp_offset = addrs[i + insn->off] - addrs[i];
2447
2448 if (!jmp_offset)
2449 /* Optimize out nop jumps */
2450 break;
2451 emit_jmp:
2452 if (is_imm8(jmp_offset)) {
2453 EMIT2(0xEB, jmp_offset);
2454 } else if (is_simm32(jmp_offset)) {
2455 EMIT1_off32(0xE9, jmp_offset);
2456 } else {
2457 pr_err("jmp gen bug %llx\n", jmp_offset);
2458 return -EFAULT;
2459 }
2460 break;
2461 case BPF_STX | BPF_ATOMIC | BPF_W:
2462 case BPF_STX | BPF_ATOMIC | BPF_DW:
2463 goto notyet;
2464 case BPF_JMP | BPF_EXIT:
2465 if (seen_exit) {
2466 jmp_offset = ctx->cleanup_addr - addrs[i];
2467 goto emit_jmp;
2468 }
2469 seen_exit = true;
2470 /* Update cleanup_addr */
2471 ctx->cleanup_addr = proglen;
2472 emit_epilogue(&prog, bpf_prog->aux->stack_depth);
2473 break;
2474 notyet:
2475 pr_info_once("*** NOT YET: opcode %02x ***\n", code);
2476 return -EFAULT;
2477 default:
2478 /*
2479 * This error will be seen if new instruction was added
2480 * to interpreter, but not to JIT or if there is junk in
2481 * bpf_prog
2482 */
2483 pr_err("bpf_jit: unknown opcode %02x\n", code);
2484 return -EINVAL;
2485 }
2486
2487 ilen = prog - temp;
2488 if (ilen > BPF_MAX_INSN_SIZE) {
2489 pr_err("bpf_jit: fatal insn size error\n");
2490 return -EFAULT;
2491 }
2492
2493 if (image) {
2494 /*
2495 * When populating the image, assert that:
2496 *
2497 * i) We do not write beyond the allocated space, and
2498 * ii) addrs[i] did not change from the prior run, in order
2499 * to validate assumptions made for computing branch
2500 * displacements.
2501 */
2502 if (unlikely(proglen + ilen > oldproglen ||
2503 proglen + ilen != addrs[i])) {
2504 pr_err("bpf_jit: fatal error\n");
2505 return -EFAULT;
2506 }
2507 memcpy(image + proglen, temp, ilen);
2508 }
2509 proglen += ilen;
2510 addrs[i] = proglen;
2511 prog = temp;
2512 }
2513 return proglen;
2514 }
2515
bpf_jit_needs_zext(void)2516 bool bpf_jit_needs_zext(void)
2517 {
2518 return true;
2519 }
2520
bpf_int_jit_compile(struct bpf_prog * prog)2521 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
2522 {
2523 struct bpf_binary_header *header = NULL;
2524 struct bpf_prog *tmp, *orig_prog = prog;
2525 int proglen, oldproglen = 0;
2526 struct jit_context ctx = {};
2527 bool tmp_blinded = false;
2528 u8 *image = NULL;
2529 int *addrs;
2530 int pass;
2531 int i;
2532
2533 if (!prog->jit_requested)
2534 return orig_prog;
2535
2536 tmp = bpf_jit_blind_constants(prog);
2537 /*
2538 * If blinding was requested and we failed during blinding,
2539 * we must fall back to the interpreter.
2540 */
2541 if (IS_ERR(tmp))
2542 return orig_prog;
2543 if (tmp != prog) {
2544 tmp_blinded = true;
2545 prog = tmp;
2546 }
2547
2548 addrs = kmalloc_array(prog->len, sizeof(*addrs), GFP_KERNEL);
2549 if (!addrs) {
2550 prog = orig_prog;
2551 goto out;
2552 }
2553
2554 /*
2555 * Before first pass, make a rough estimation of addrs[]
2556 * each BPF instruction is translated to less than 64 bytes
2557 */
2558 for (proglen = 0, i = 0; i < prog->len; i++) {
2559 proglen += 64;
2560 addrs[i] = proglen;
2561 }
2562 ctx.cleanup_addr = proglen;
2563
2564 /*
2565 * JITed image shrinks with every pass and the loop iterates
2566 * until the image stops shrinking. Very large BPF programs
2567 * may converge on the last pass. In such case do one more
2568 * pass to emit the final image.
2569 */
2570 for (pass = 0; pass < 20 || image; pass++) {
2571 proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
2572 if (proglen <= 0) {
2573 out_image:
2574 image = NULL;
2575 if (header)
2576 bpf_jit_binary_free(header);
2577 prog = orig_prog;
2578 goto out_addrs;
2579 }
2580 if (image) {
2581 if (proglen != oldproglen) {
2582 pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
2583 proglen, oldproglen);
2584 goto out_image;
2585 }
2586 break;
2587 }
2588 if (proglen == oldproglen) {
2589 header = bpf_jit_binary_alloc(proglen, &image,
2590 1, jit_fill_hole);
2591 if (!header) {
2592 prog = orig_prog;
2593 goto out_addrs;
2594 }
2595 }
2596 oldproglen = proglen;
2597 cond_resched();
2598 }
2599
2600 if (bpf_jit_enable > 1)
2601 bpf_jit_dump(prog->len, proglen, pass + 1, image);
2602
2603 if (image && !bpf_jit_binary_lock_ro(header)) {
2604 prog->bpf_func = (void *)image;
2605 prog->jited = 1;
2606 prog->jited_len = proglen;
2607 } else {
2608 prog = orig_prog;
2609 }
2610
2611 out_addrs:
2612 kfree(addrs);
2613 out:
2614 if (tmp_blinded)
2615 bpf_jit_prog_release_other(prog, prog == orig_prog ?
2616 tmp : orig_prog);
2617 return prog;
2618 }
2619
bpf_jit_supports_kfunc_call(void)2620 bool bpf_jit_supports_kfunc_call(void)
2621 {
2622 return true;
2623 }
2624