Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
[linux-2.6.git] / arch / x86 / net / bpf_jit_comp.c
1 /* bpf_jit_comp.c : BPF JIT compiler
2  *
3  * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com)
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License
7  * as published by the Free Software Foundation; version 2
8  * of the License.
9  */
10 #include <linux/moduleloader.h>
11 #include <asm/cacheflush.h>
12 #include <linux/netdevice.h>
13 #include <linux/filter.h>
14
15 /*
16  * Conventions :
17  *  EAX : BPF A accumulator
18  *  EBX : BPF X accumulator
19  *  RDI : pointer to skb   (first argument given to JIT function)
20  *  RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
21  *  ECX,EDX,ESI : scratch registers
22  *  r9d : skb->len - skb->data_len (headlen)
23  *  r8  : skb->data
24  * -8(RBP) : saved RBX value
25  * -16(RBP)..-80(RBP) : BPF_MEMWORDS values
26  */
27 int bpf_jit_enable __read_mostly;
28
29 /*
30  * assembly code in arch/x86/net/bpf_jit.S
31  */
32 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
33 extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
34
35 static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
36 {
37         if (len == 1)
38                 *ptr = bytes;
39         else if (len == 2)
40                 *(u16 *)ptr = bytes;
41         else {
42                 *(u32 *)ptr = bytes;
43                 barrier();
44         }
45         return ptr + len;
46 }
47
48 #define EMIT(bytes, len)        do { prog = emit_code(prog, bytes, len); } while (0)
49
50 #define EMIT1(b1)               EMIT(b1, 1)
51 #define EMIT2(b1, b2)           EMIT((b1) + ((b2) << 8), 2)
52 #define EMIT3(b1, b2, b3)       EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
53 #define EMIT4(b1, b2, b3, b4)   EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
54 #define EMIT1_off32(b1, off)    do { EMIT1(b1); EMIT(off, 4);} while (0)
55
56 #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
57 #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
58
59 static inline bool is_imm8(int value)
60 {
61         return value <= 127 && value >= -128;
62 }
63
64 static inline bool is_near(int offset)
65 {
66         return offset <= 127 && offset >= -128;
67 }
68
69 #define EMIT_JMP(offset)                                                \
70 do {                                                                    \
71         if (offset) {                                                   \
72                 if (is_near(offset))                                    \
73                         EMIT2(0xeb, offset); /* jmp .+off8 */           \
74                 else                                                    \
75                         EMIT1_off32(0xe9, offset); /* jmp .+off32 */    \
76         }                                                               \
77 } while (0)
78
79 /* list of x86 cond jumps opcodes (. + s8)
80  * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
81  */
82 #define X86_JB  0x72
83 #define X86_JAE 0x73
84 #define X86_JE  0x74
85 #define X86_JNE 0x75
86 #define X86_JBE 0x76
87 #define X86_JA  0x77
88
89 #define EMIT_COND_JMP(op, offset)                               \
90 do {                                                            \
91         if (is_near(offset))                                    \
92                 EMIT2(op, offset); /* jxx .+off8 */             \
93         else {                                                  \
94                 EMIT2(0x0f, op + 0x10);                         \
95                 EMIT(offset, 4); /* jxx .+off32 */              \
96         }                                                       \
97 } while (0)
98
99 #define COND_SEL(CODE, TOP, FOP)        \
100         case CODE:                      \
101                 t_op = TOP;             \
102                 f_op = FOP;             \
103                 goto cond_branch
104
105
106 #define SEEN_DATAREF 1 /* might call external helpers */
107 #define SEEN_XREG    2 /* ebx is used */
108 #define SEEN_MEM     4 /* use mem[] for temporary storage */
109
110 static inline void bpf_flush_icache(void *start, void *end)
111 {
112         mm_segment_t old_fs = get_fs();
113
114         set_fs(KERNEL_DS);
115         smp_wmb();
116         flush_icache_range((unsigned long)start, (unsigned long)end);
117         set_fs(old_fs);
118 }
119
120
121 void bpf_jit_compile(struct sk_filter *fp)
122 {
123         u8 temp[64];
124         u8 *prog;
125         unsigned int proglen, oldproglen = 0;
126         int ilen, i;
127         int t_offset, f_offset;
128         u8 t_op, f_op, seen = 0, pass;
129         u8 *image = NULL;
130         u8 *func;
131         int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
132         unsigned int cleanup_addr; /* epilogue code offset */
133         unsigned int *addrs;
134         const struct sock_filter *filter = fp->insns;
135         int flen = fp->len;
136
137         if (!bpf_jit_enable)
138                 return;
139
140         addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
141         if (addrs == NULL)
142                 return;
143
144         /* Before first pass, make a rough estimation of addrs[]
145          * each bpf instruction is translated to less than 64 bytes
146          */
147         for (proglen = 0, i = 0; i < flen; i++) {
148                 proglen += 64;
149                 addrs[i] = proglen;
150         }
151         cleanup_addr = proglen; /* epilogue address */
152
153         for (pass = 0; pass < 10; pass++) {
154                 /* no prologue/epilogue for trivial filters (RET something) */
155                 proglen = 0;
156                 prog = temp;
157
158                 if (seen) {
159                         EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
160                         EMIT4(0x48, 0x83, 0xec, 96);    /* subq  $96,%rsp       */
161                         /* note : must save %rbx in case bpf_error is hit */
162                         if (seen & (SEEN_XREG | SEEN_DATAREF))
163                                 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
164                         if (seen & SEEN_XREG)
165                                 CLEAR_X(); /* make sure we dont leek kernel memory */
166
167                         /*
168                          * If this filter needs to access skb data,
169                          * loads r9 and r8 with :
170                          *  r9 = skb->len - skb->data_len
171                          *  r8 = skb->data
172                          */
173                         if (seen & SEEN_DATAREF) {
174                                 if (offsetof(struct sk_buff, len) <= 127)
175                                         /* mov    off8(%rdi),%r9d */
176                                         EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
177                                 else {
178                                         /* mov    off32(%rdi),%r9d */
179                                         EMIT3(0x44, 0x8b, 0x8f);
180                                         EMIT(offsetof(struct sk_buff, len), 4);
181                                 }
182                                 if (is_imm8(offsetof(struct sk_buff, data_len)))
183                                         /* sub    off8(%rdi),%r9d */
184                                         EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
185                                 else {
186                                         EMIT3(0x44, 0x2b, 0x8f);
187                                         EMIT(offsetof(struct sk_buff, data_len), 4);
188                                 }
189
190                                 if (is_imm8(offsetof(struct sk_buff, data)))
191                                         /* mov off8(%rdi),%r8 */
192                                         EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
193                                 else {
194                                         /* mov off32(%rdi),%r8 */
195                                         EMIT3(0x4c, 0x8b, 0x87);
196                                         EMIT(offsetof(struct sk_buff, data), 4);
197                                 }
198                         }
199                 }
200
201                 switch (filter[0].code) {
202                 case BPF_S_RET_K:
203                 case BPF_S_LD_W_LEN:
204                 case BPF_S_ANC_PROTOCOL:
205                 case BPF_S_ANC_IFINDEX:
206                 case BPF_S_ANC_MARK:
207                 case BPF_S_ANC_RXHASH:
208                 case BPF_S_ANC_CPU:
209                 case BPF_S_ANC_QUEUE:
210                 case BPF_S_LD_W_ABS:
211                 case BPF_S_LD_H_ABS:
212                 case BPF_S_LD_B_ABS:
213                         /* first instruction sets A register (or is RET 'constant') */
214                         break;
215                 default:
216                         /* make sure we dont leak kernel information to user */
217                         CLEAR_A(); /* A = 0 */
218                 }
219
220                 for (i = 0; i < flen; i++) {
221                         unsigned int K = filter[i].k;
222
223                         switch (filter[i].code) {
224                         case BPF_S_ALU_ADD_X: /* A += X; */
225                                 seen |= SEEN_XREG;
226                                 EMIT2(0x01, 0xd8);              /* add %ebx,%eax */
227                                 break;
228                         case BPF_S_ALU_ADD_K: /* A += K; */
229                                 if (!K)
230                                         break;
231                                 if (is_imm8(K))
232                                         EMIT3(0x83, 0xc0, K);   /* add imm8,%eax */
233                                 else
234                                         EMIT1_off32(0x05, K);   /* add imm32,%eax */
235                                 break;
236                         case BPF_S_ALU_SUB_X: /* A -= X; */
237                                 seen |= SEEN_XREG;
238                                 EMIT2(0x29, 0xd8);              /* sub    %ebx,%eax */
239                                 break;
240                         case BPF_S_ALU_SUB_K: /* A -= K */
241                                 if (!K)
242                                         break;
243                                 if (is_imm8(K))
244                                         EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
245                                 else
246                                         EMIT1_off32(0x2d, K); /* sub imm32,%eax */
247                                 break;
248                         case BPF_S_ALU_MUL_X: /* A *= X; */
249                                 seen |= SEEN_XREG;
250                                 EMIT3(0x0f, 0xaf, 0xc3);        /* imul %ebx,%eax */
251                                 break;
252                         case BPF_S_ALU_MUL_K: /* A *= K */
253                                 if (is_imm8(K))
254                                         EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
255                                 else {
256                                         EMIT2(0x69, 0xc0);              /* imul imm32,%eax */
257                                         EMIT(K, 4);
258                                 }
259                                 break;
260                         case BPF_S_ALU_DIV_X: /* A /= X; */
261                                 seen |= SEEN_XREG;
262                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
263                                 if (pc_ret0 != -1)
264                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0] - (addrs[i] - 4));
265                                 else {
266                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
267                                         CLEAR_A();
268                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
269                                 }
270                                 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
271                                 break;
272                         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
273                                 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
274                                 EMIT(K, 4);
275                                 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
276                                 break;
277                         case BPF_S_ALU_AND_X:
278                                 seen |= SEEN_XREG;
279                                 EMIT2(0x21, 0xd8);              /* and %ebx,%eax */
280                                 break;
281                         case BPF_S_ALU_AND_K:
282                                 if (K >= 0xFFFFFF00) {
283                                         EMIT2(0x24, K & 0xFF); /* and imm8,%al */
284                                 } else if (K >= 0xFFFF0000) {
285                                         EMIT2(0x66, 0x25);      /* and imm16,%ax */
286                                         EMIT2(K, 2);
287                                 } else {
288                                         EMIT1_off32(0x25, K);   /* and imm32,%eax */
289                                 }
290                                 break;
291                         case BPF_S_ALU_OR_X:
292                                 seen |= SEEN_XREG;
293                                 EMIT2(0x09, 0xd8);              /* or %ebx,%eax */
294                                 break;
295                         case BPF_S_ALU_OR_K:
296                                 if (is_imm8(K))
297                                         EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
298                                 else
299                                         EMIT1_off32(0x0d, K);   /* or imm32,%eax */
300                                 break;
301                         case BPF_S_ALU_LSH_X: /* A <<= X; */
302                                 seen |= SEEN_XREG;
303                                 EMIT4(0x89, 0xd9, 0xd3, 0xe0);  /* mov %ebx,%ecx; shl %cl,%eax */
304                                 break;
305                         case BPF_S_ALU_LSH_K:
306                                 if (K == 0)
307                                         break;
308                                 else if (K == 1)
309                                         EMIT2(0xd1, 0xe0); /* shl %eax */
310                                 else
311                                         EMIT3(0xc1, 0xe0, K);
312                                 break;
313                         case BPF_S_ALU_RSH_X: /* A >>= X; */
314                                 seen |= SEEN_XREG;
315                                 EMIT4(0x89, 0xd9, 0xd3, 0xe8);  /* mov %ebx,%ecx; shr %cl,%eax */
316                                 break;
317                         case BPF_S_ALU_RSH_K: /* A >>= K; */
318                                 if (K == 0)
319                                         break;
320                                 else if (K == 1)
321                                         EMIT2(0xd1, 0xe8); /* shr %eax */
322                                 else
323                                         EMIT3(0xc1, 0xe8, K);
324                                 break;
325                         case BPF_S_ALU_NEG:
326                                 EMIT2(0xf7, 0xd8);              /* neg %eax */
327                                 break;
328                         case BPF_S_RET_K:
329                                 if (!K) {
330                                         if (pc_ret0 == -1)
331                                                 pc_ret0 = i;
332                                         CLEAR_A();
333                                 } else {
334                                         EMIT1_off32(0xb8, K);   /* mov $imm32,%eax */
335                                 }
336                                 /* fallinto */
337                         case BPF_S_RET_A:
338                                 if (seen) {
339                                         if (i != flen - 1) {
340                                                 EMIT_JMP(cleanup_addr - addrs[i]);
341                                                 break;
342                                         }
343                                         if (seen & SEEN_XREG)
344                                                 EMIT4(0x48, 0x8b, 0x5d, 0xf8);  /* mov  -8(%rbp),%rbx */
345                                         EMIT1(0xc9);            /* leaveq */
346                                 }
347                                 EMIT1(0xc3);            /* ret */
348                                 break;
349                         case BPF_S_MISC_TAX: /* X = A */
350                                 seen |= SEEN_XREG;
351                                 EMIT2(0x89, 0xc3);      /* mov    %eax,%ebx */
352                                 break;
353                         case BPF_S_MISC_TXA: /* A = X */
354                                 seen |= SEEN_XREG;
355                                 EMIT2(0x89, 0xd8);      /* mov    %ebx,%eax */
356                                 break;
357                         case BPF_S_LD_IMM: /* A = K */
358                                 if (!K)
359                                         CLEAR_A();
360                                 else
361                                         EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
362                                 break;
363                         case BPF_S_LDX_IMM: /* X = K */
364                                 seen |= SEEN_XREG;
365                                 if (!K)
366                                         CLEAR_X();
367                                 else
368                                         EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
369                                 break;
370                         case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
371                                 seen |= SEEN_MEM;
372                                 EMIT3(0x8b, 0x45, 0xf0 - K*4);
373                                 break;
374                         case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
375                                 seen |= SEEN_XREG | SEEN_MEM;
376                                 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
377                                 break;
378                         case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
379                                 seen |= SEEN_MEM;
380                                 EMIT3(0x89, 0x45, 0xf0 - K*4);
381                                 break;
382                         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
383                                 seen |= SEEN_XREG | SEEN_MEM;
384                                 EMIT3(0x89, 0x5d, 0xf0 - K*4);
385                                 break;
386                         case BPF_S_LD_W_LEN: /* A = skb->len; */
387                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
388                                 if (is_imm8(offsetof(struct sk_buff, len)))
389                                         /* mov    off8(%rdi),%eax */
390                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
391                                 else {
392                                         EMIT2(0x8b, 0x87);
393                                         EMIT(offsetof(struct sk_buff, len), 4);
394                                 }
395                                 break;
396                         case BPF_S_LDX_W_LEN: /* X = skb->len; */
397                                 seen |= SEEN_XREG;
398                                 if (is_imm8(offsetof(struct sk_buff, len)))
399                                         /* mov off8(%rdi),%ebx */
400                                         EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
401                                 else {
402                                         EMIT2(0x8b, 0x9f);
403                                         EMIT(offsetof(struct sk_buff, len), 4);
404                                 }
405                                 break;
406                         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
407                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
408                                 if (is_imm8(offsetof(struct sk_buff, protocol))) {
409                                         /* movzwl off8(%rdi),%eax */
410                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
411                                 } else {
412                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
413                                         EMIT(offsetof(struct sk_buff, protocol), 4);
414                                 }
415                                 EMIT2(0x86, 0xc4); /* ntohs() : xchg   %al,%ah */
416                                 break;
417                         case BPF_S_ANC_IFINDEX:
418                                 if (is_imm8(offsetof(struct sk_buff, dev))) {
419                                         /* movq off8(%rdi),%rax */
420                                         EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
421                                 } else {
422                                         EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
423                                         EMIT(offsetof(struct sk_buff, dev), 4);
424                                 }
425                                 EMIT3(0x48, 0x85, 0xc0);        /* test %rax,%rax */
426                                 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
427                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
428                                 EMIT2(0x8b, 0x80);      /* mov off32(%rax),%eax */
429                                 EMIT(offsetof(struct net_device, ifindex), 4);
430                                 break;
431                         case BPF_S_ANC_MARK:
432                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
433                                 if (is_imm8(offsetof(struct sk_buff, mark))) {
434                                         /* mov off8(%rdi),%eax */
435                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
436                                 } else {
437                                         EMIT2(0x8b, 0x87);
438                                         EMIT(offsetof(struct sk_buff, mark), 4);
439                                 }
440                                 break;
441                         case BPF_S_ANC_RXHASH:
442                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
443                                 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
444                                         /* mov off8(%rdi),%eax */
445                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
446                                 } else {
447                                         EMIT2(0x8b, 0x87);
448                                         EMIT(offsetof(struct sk_buff, rxhash), 4);
449                                 }
450                                 break;
451                         case BPF_S_ANC_QUEUE:
452                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
453                                 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
454                                         /* movzwl off8(%rdi),%eax */
455                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
456                                 } else {
457                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
458                                         EMIT(offsetof(struct sk_buff, queue_mapping), 4);
459                                 }
460                                 break;
461                         case BPF_S_ANC_CPU:
462 #ifdef CONFIG_SMP
463                                 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
464                                 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
465 #else
466                                 CLEAR_A();
467 #endif
468                                 break;
469                         case BPF_S_LD_W_ABS:
470                                 func = sk_load_word;
471 common_load:                    seen |= SEEN_DATAREF;
472                                 if ((int)K < 0)
473                                         goto out;
474                                 t_offset = func - (image + addrs[i]);
475                                 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
476                                 EMIT1_off32(0xe8, t_offset); /* call */
477                                 break;
478                         case BPF_S_LD_H_ABS:
479                                 func = sk_load_half;
480                                 goto common_load;
481                         case BPF_S_LD_B_ABS:
482                                 func = sk_load_byte;
483                                 goto common_load;
484                         case BPF_S_LDX_B_MSH:
485                                 if ((int)K < 0) {
486                                         if (pc_ret0 != -1) {
487                                                 EMIT_JMP(addrs[pc_ret0] - addrs[i]);
488                                                 break;
489                                         }
490                                         CLEAR_A();
491                                         EMIT_JMP(cleanup_addr - addrs[i]);
492                                         break;
493                                 }
494                                 seen |= SEEN_DATAREF | SEEN_XREG;
495                                 t_offset = sk_load_byte_msh - (image + addrs[i]);
496                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi */
497                                 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
498                                 break;
499                         case BPF_S_LD_W_IND:
500                                 func = sk_load_word_ind;
501 common_load_ind:                seen |= SEEN_DATAREF | SEEN_XREG;
502                                 t_offset = func - (image + addrs[i]);
503                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi   */
504                                 EMIT1_off32(0xe8, t_offset);    /* call sk_load_xxx_ind */
505                                 break;
506                         case BPF_S_LD_H_IND:
507                                 func = sk_load_half_ind;
508                                 goto common_load_ind;
509                         case BPF_S_LD_B_IND:
510                                 func = sk_load_byte_ind;
511                                 goto common_load_ind;
512                         case BPF_S_JMP_JA:
513                                 t_offset = addrs[i + K] - addrs[i];
514                                 EMIT_JMP(t_offset);
515                                 break;
516                         COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
517                         COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
518                         COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
519                         COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
520                         COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
521                         COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
522                         COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
523                         COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
524
525 cond_branch:                    f_offset = addrs[i + filter[i].jf] - addrs[i];
526                                 t_offset = addrs[i + filter[i].jt] - addrs[i];
527
528                                 /* same targets, can avoid doing the test :) */
529                                 if (filter[i].jt == filter[i].jf) {
530                                         EMIT_JMP(t_offset);
531                                         break;
532                                 }
533
534                                 switch (filter[i].code) {
535                                 case BPF_S_JMP_JGT_X:
536                                 case BPF_S_JMP_JGE_X:
537                                 case BPF_S_JMP_JEQ_X:
538                                         seen |= SEEN_XREG;
539                                         EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
540                                         break;
541                                 case BPF_S_JMP_JSET_X:
542                                         seen |= SEEN_XREG;
543                                         EMIT2(0x85, 0xd8); /* test %ebx,%eax */
544                                         break;
545                                 case BPF_S_JMP_JEQ_K:
546                                         if (K == 0) {
547                                                 EMIT2(0x85, 0xc0); /* test   %eax,%eax */
548                                                 break;
549                                         }
550                                 case BPF_S_JMP_JGT_K:
551                                 case BPF_S_JMP_JGE_K:
552                                         if (K <= 127)
553                                                 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
554                                         else
555                                                 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
556                                         break;
557                                 case BPF_S_JMP_JSET_K:
558                                         if (K <= 0xFF)
559                                                 EMIT2(0xa8, K); /* test imm8,%al */
560                                         else if (!(K & 0xFFFF00FF))
561                                                 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
562                                         else if (K <= 0xFFFF) {
563                                                 EMIT2(0x66, 0xa9); /* test imm16,%ax */
564                                                 EMIT(K, 2);
565                                         } else {
566                                                 EMIT1_off32(0xa9, K); /* test imm32,%eax */
567                                         }
568                                         break;
569                                 }
570                                 if (filter[i].jt != 0) {
571                                         if (filter[i].jf && f_offset)
572                                                 t_offset += is_near(f_offset) ? 2 : 5;
573                                         EMIT_COND_JMP(t_op, t_offset);
574                                         if (filter[i].jf)
575                                                 EMIT_JMP(f_offset);
576                                         break;
577                                 }
578                                 EMIT_COND_JMP(f_op, f_offset);
579                                 break;
580                         default:
581                                 /* hmm, too complex filter, give up with jit compiler */
582                                 goto out;
583                         }
584                         ilen = prog - temp;
585                         if (image) {
586                                 if (unlikely(proglen + ilen > oldproglen)) {
587                                         pr_err("bpb_jit_compile fatal error\n");
588                                         kfree(addrs);
589                                         module_free(NULL, image);
590                                         return;
591                                 }
592                                 memcpy(image + proglen, temp, ilen);
593                         }
594                         proglen += ilen;
595                         addrs[i] = proglen;
596                         prog = temp;
597                 }
598                 /* last bpf instruction is always a RET :
599                  * use it to give the cleanup instruction(s) addr
600                  */
601                 cleanup_addr = proglen - 1; /* ret */
602                 if (seen)
603                         cleanup_addr -= 1; /* leaveq */
604                 if (seen & SEEN_XREG)
605                         cleanup_addr -= 4; /* mov  -8(%rbp),%rbx */
606
607                 if (image) {
608                         WARN_ON(proglen != oldproglen);
609                         break;
610                 }
611                 if (proglen == oldproglen) {
612                         image = module_alloc(max_t(unsigned int,
613                                                    proglen,
614                                                    sizeof(struct work_struct)));
615                         if (!image)
616                                 goto out;
617                 }
618                 oldproglen = proglen;
619         }
620         if (bpf_jit_enable > 1)
621                 pr_err("flen=%d proglen=%u pass=%d image=%p\n",
622                        flen, proglen, pass, image);
623
624         if (image) {
625                 if (bpf_jit_enable > 1)
626                         print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS,
627                                        16, 1, image, proglen, false);
628
629                 bpf_flush_icache(image, image + proglen);
630
631                 fp->bpf_func = (void *)image;
632         }
633 out:
634         kfree(addrs);
635         return;
636 }
637
638 static void jit_free_defer(struct work_struct *arg)
639 {
640         module_free(NULL, arg);
641 }
642
643 /* run from softirq, we must use a work_struct to call
644  * module_free() from process context
645  */
646 void bpf_jit_free(struct sk_filter *fp)
647 {
648         if (fp->bpf_func != sk_run_filter) {
649                 struct work_struct *work = (struct work_struct *)fp->bpf_func;
650
651                 INIT_WORK(work, jit_free_defer);
652                 schedule_work(work);
653         }
654 }