[S390] Fix build errors (fallout from system.h disintegration)
[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                 u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
155                 /* no prologue/epilogue for trivial filters (RET something) */
156                 proglen = 0;
157                 prog = temp;
158
159                 if (seen_or_pass0) {
160                         EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
161                         EMIT4(0x48, 0x83, 0xec, 96);    /* subq  $96,%rsp       */
162                         /* note : must save %rbx in case bpf_error is hit */
163                         if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
164                                 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
165                         if (seen_or_pass0 & SEEN_XREG)
166                                 CLEAR_X(); /* make sure we dont leek kernel memory */
167
168                         /*
169                          * If this filter needs to access skb data,
170                          * loads r9 and r8 with :
171                          *  r9 = skb->len - skb->data_len
172                          *  r8 = skb->data
173                          */
174                         if (seen_or_pass0 & SEEN_DATAREF) {
175                                 if (offsetof(struct sk_buff, len) <= 127)
176                                         /* mov    off8(%rdi),%r9d */
177                                         EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
178                                 else {
179                                         /* mov    off32(%rdi),%r9d */
180                                         EMIT3(0x44, 0x8b, 0x8f);
181                                         EMIT(offsetof(struct sk_buff, len), 4);
182                                 }
183                                 if (is_imm8(offsetof(struct sk_buff, data_len)))
184                                         /* sub    off8(%rdi),%r9d */
185                                         EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
186                                 else {
187                                         EMIT3(0x44, 0x2b, 0x8f);
188                                         EMIT(offsetof(struct sk_buff, data_len), 4);
189                                 }
190
191                                 if (is_imm8(offsetof(struct sk_buff, data)))
192                                         /* mov off8(%rdi),%r8 */
193                                         EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
194                                 else {
195                                         /* mov off32(%rdi),%r8 */
196                                         EMIT3(0x4c, 0x8b, 0x87);
197                                         EMIT(offsetof(struct sk_buff, data), 4);
198                                 }
199                         }
200                 }
201
202                 switch (filter[0].code) {
203                 case BPF_S_RET_K:
204                 case BPF_S_LD_W_LEN:
205                 case BPF_S_ANC_PROTOCOL:
206                 case BPF_S_ANC_IFINDEX:
207                 case BPF_S_ANC_MARK:
208                 case BPF_S_ANC_RXHASH:
209                 case BPF_S_ANC_CPU:
210                 case BPF_S_ANC_QUEUE:
211                 case BPF_S_LD_W_ABS:
212                 case BPF_S_LD_H_ABS:
213                 case BPF_S_LD_B_ABS:
214                         /* first instruction sets A register (or is RET 'constant') */
215                         break;
216                 default:
217                         /* make sure we dont leak kernel information to user */
218                         CLEAR_A(); /* A = 0 */
219                 }
220
221                 for (i = 0; i < flen; i++) {
222                         unsigned int K = filter[i].k;
223
224                         switch (filter[i].code) {
225                         case BPF_S_ALU_ADD_X: /* A += X; */
226                                 seen |= SEEN_XREG;
227                                 EMIT2(0x01, 0xd8);              /* add %ebx,%eax */
228                                 break;
229                         case BPF_S_ALU_ADD_K: /* A += K; */
230                                 if (!K)
231                                         break;
232                                 if (is_imm8(K))
233                                         EMIT3(0x83, 0xc0, K);   /* add imm8,%eax */
234                                 else
235                                         EMIT1_off32(0x05, K);   /* add imm32,%eax */
236                                 break;
237                         case BPF_S_ALU_SUB_X: /* A -= X; */
238                                 seen |= SEEN_XREG;
239                                 EMIT2(0x29, 0xd8);              /* sub    %ebx,%eax */
240                                 break;
241                         case BPF_S_ALU_SUB_K: /* A -= K */
242                                 if (!K)
243                                         break;
244                                 if (is_imm8(K))
245                                         EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
246                                 else
247                                         EMIT1_off32(0x2d, K); /* sub imm32,%eax */
248                                 break;
249                         case BPF_S_ALU_MUL_X: /* A *= X; */
250                                 seen |= SEEN_XREG;
251                                 EMIT3(0x0f, 0xaf, 0xc3);        /* imul %ebx,%eax */
252                                 break;
253                         case BPF_S_ALU_MUL_K: /* A *= K */
254                                 if (is_imm8(K))
255                                         EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
256                                 else {
257                                         EMIT2(0x69, 0xc0);              /* imul imm32,%eax */
258                                         EMIT(K, 4);
259                                 }
260                                 break;
261                         case BPF_S_ALU_DIV_X: /* A /= X; */
262                                 seen |= SEEN_XREG;
263                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
264                                 if (pc_ret0 > 0) {
265                                         /* addrs[pc_ret0 - 1] is start address of target
266                                          * (addrs[i] - 4) is the address following this jmp
267                                          * ("xor %edx,%edx; div %ebx" being 4 bytes long)
268                                          */
269                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
270                                                                 (addrs[i] - 4));
271                                 } else {
272                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
273                                         CLEAR_A();
274                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
275                                 }
276                                 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
277                                 break;
278                         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
279                                 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
280                                 EMIT(K, 4);
281                                 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
282                                 break;
283                         case BPF_S_ALU_AND_X:
284                                 seen |= SEEN_XREG;
285                                 EMIT2(0x21, 0xd8);              /* and %ebx,%eax */
286                                 break;
287                         case BPF_S_ALU_AND_K:
288                                 if (K >= 0xFFFFFF00) {
289                                         EMIT2(0x24, K & 0xFF); /* and imm8,%al */
290                                 } else if (K >= 0xFFFF0000) {
291                                         EMIT2(0x66, 0x25);      /* and imm16,%ax */
292                                         EMIT2(K, 2);
293                                 } else {
294                                         EMIT1_off32(0x25, K);   /* and imm32,%eax */
295                                 }
296                                 break;
297                         case BPF_S_ALU_OR_X:
298                                 seen |= SEEN_XREG;
299                                 EMIT2(0x09, 0xd8);              /* or %ebx,%eax */
300                                 break;
301                         case BPF_S_ALU_OR_K:
302                                 if (is_imm8(K))
303                                         EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
304                                 else
305                                         EMIT1_off32(0x0d, K);   /* or imm32,%eax */
306                                 break;
307                         case BPF_S_ALU_LSH_X: /* A <<= X; */
308                                 seen |= SEEN_XREG;
309                                 EMIT4(0x89, 0xd9, 0xd3, 0xe0);  /* mov %ebx,%ecx; shl %cl,%eax */
310                                 break;
311                         case BPF_S_ALU_LSH_K:
312                                 if (K == 0)
313                                         break;
314                                 else if (K == 1)
315                                         EMIT2(0xd1, 0xe0); /* shl %eax */
316                                 else
317                                         EMIT3(0xc1, 0xe0, K);
318                                 break;
319                         case BPF_S_ALU_RSH_X: /* A >>= X; */
320                                 seen |= SEEN_XREG;
321                                 EMIT4(0x89, 0xd9, 0xd3, 0xe8);  /* mov %ebx,%ecx; shr %cl,%eax */
322                                 break;
323                         case BPF_S_ALU_RSH_K: /* A >>= K; */
324                                 if (K == 0)
325                                         break;
326                                 else if (K == 1)
327                                         EMIT2(0xd1, 0xe8); /* shr %eax */
328                                 else
329                                         EMIT3(0xc1, 0xe8, K);
330                                 break;
331                         case BPF_S_ALU_NEG:
332                                 EMIT2(0xf7, 0xd8);              /* neg %eax */
333                                 break;
334                         case BPF_S_RET_K:
335                                 if (!K) {
336                                         if (pc_ret0 == -1)
337                                                 pc_ret0 = i;
338                                         CLEAR_A();
339                                 } else {
340                                         EMIT1_off32(0xb8, K);   /* mov $imm32,%eax */
341                                 }
342                                 /* fallinto */
343                         case BPF_S_RET_A:
344                                 if (seen_or_pass0) {
345                                         if (i != flen - 1) {
346                                                 EMIT_JMP(cleanup_addr - addrs[i]);
347                                                 break;
348                                         }
349                                         if (seen_or_pass0 & SEEN_XREG)
350                                                 EMIT4(0x48, 0x8b, 0x5d, 0xf8);  /* mov  -8(%rbp),%rbx */
351                                         EMIT1(0xc9);            /* leaveq */
352                                 }
353                                 EMIT1(0xc3);            /* ret */
354                                 break;
355                         case BPF_S_MISC_TAX: /* X = A */
356                                 seen |= SEEN_XREG;
357                                 EMIT2(0x89, 0xc3);      /* mov    %eax,%ebx */
358                                 break;
359                         case BPF_S_MISC_TXA: /* A = X */
360                                 seen |= SEEN_XREG;
361                                 EMIT2(0x89, 0xd8);      /* mov    %ebx,%eax */
362                                 break;
363                         case BPF_S_LD_IMM: /* A = K */
364                                 if (!K)
365                                         CLEAR_A();
366                                 else
367                                         EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
368                                 break;
369                         case BPF_S_LDX_IMM: /* X = K */
370                                 seen |= SEEN_XREG;
371                                 if (!K)
372                                         CLEAR_X();
373                                 else
374                                         EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
375                                 break;
376                         case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
377                                 seen |= SEEN_MEM;
378                                 EMIT3(0x8b, 0x45, 0xf0 - K*4);
379                                 break;
380                         case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
381                                 seen |= SEEN_XREG | SEEN_MEM;
382                                 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
383                                 break;
384                         case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
385                                 seen |= SEEN_MEM;
386                                 EMIT3(0x89, 0x45, 0xf0 - K*4);
387                                 break;
388                         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
389                                 seen |= SEEN_XREG | SEEN_MEM;
390                                 EMIT3(0x89, 0x5d, 0xf0 - K*4);
391                                 break;
392                         case BPF_S_LD_W_LEN: /* A = skb->len; */
393                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
394                                 if (is_imm8(offsetof(struct sk_buff, len)))
395                                         /* mov    off8(%rdi),%eax */
396                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
397                                 else {
398                                         EMIT2(0x8b, 0x87);
399                                         EMIT(offsetof(struct sk_buff, len), 4);
400                                 }
401                                 break;
402                         case BPF_S_LDX_W_LEN: /* X = skb->len; */
403                                 seen |= SEEN_XREG;
404                                 if (is_imm8(offsetof(struct sk_buff, len)))
405                                         /* mov off8(%rdi),%ebx */
406                                         EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
407                                 else {
408                                         EMIT2(0x8b, 0x9f);
409                                         EMIT(offsetof(struct sk_buff, len), 4);
410                                 }
411                                 break;
412                         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
413                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
414                                 if (is_imm8(offsetof(struct sk_buff, protocol))) {
415                                         /* movzwl off8(%rdi),%eax */
416                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
417                                 } else {
418                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
419                                         EMIT(offsetof(struct sk_buff, protocol), 4);
420                                 }
421                                 EMIT2(0x86, 0xc4); /* ntohs() : xchg   %al,%ah */
422                                 break;
423                         case BPF_S_ANC_IFINDEX:
424                                 if (is_imm8(offsetof(struct sk_buff, dev))) {
425                                         /* movq off8(%rdi),%rax */
426                                         EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
427                                 } else {
428                                         EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
429                                         EMIT(offsetof(struct sk_buff, dev), 4);
430                                 }
431                                 EMIT3(0x48, 0x85, 0xc0);        /* test %rax,%rax */
432                                 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
433                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
434                                 EMIT2(0x8b, 0x80);      /* mov off32(%rax),%eax */
435                                 EMIT(offsetof(struct net_device, ifindex), 4);
436                                 break;
437                         case BPF_S_ANC_MARK:
438                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
439                                 if (is_imm8(offsetof(struct sk_buff, mark))) {
440                                         /* mov off8(%rdi),%eax */
441                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
442                                 } else {
443                                         EMIT2(0x8b, 0x87);
444                                         EMIT(offsetof(struct sk_buff, mark), 4);
445                                 }
446                                 break;
447                         case BPF_S_ANC_RXHASH:
448                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
449                                 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
450                                         /* mov off8(%rdi),%eax */
451                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
452                                 } else {
453                                         EMIT2(0x8b, 0x87);
454                                         EMIT(offsetof(struct sk_buff, rxhash), 4);
455                                 }
456                                 break;
457                         case BPF_S_ANC_QUEUE:
458                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
459                                 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
460                                         /* movzwl off8(%rdi),%eax */
461                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
462                                 } else {
463                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
464                                         EMIT(offsetof(struct sk_buff, queue_mapping), 4);
465                                 }
466                                 break;
467                         case BPF_S_ANC_CPU:
468 #ifdef CONFIG_SMP
469                                 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
470                                 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
471 #else
472                                 CLEAR_A();
473 #endif
474                                 break;
475                         case BPF_S_LD_W_ABS:
476                                 func = sk_load_word;
477 common_load:                    seen |= SEEN_DATAREF;
478                                 if ((int)K < 0) {
479                                         /* Abort the JIT because __load_pointer() is needed. */
480                                         goto out;
481                                 }
482                                 t_offset = func - (image + addrs[i]);
483                                 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
484                                 EMIT1_off32(0xe8, t_offset); /* call */
485                                 break;
486                         case BPF_S_LD_H_ABS:
487                                 func = sk_load_half;
488                                 goto common_load;
489                         case BPF_S_LD_B_ABS:
490                                 func = sk_load_byte;
491                                 goto common_load;
492                         case BPF_S_LDX_B_MSH:
493                                 if ((int)K < 0) {
494                                         /* Abort the JIT because __load_pointer() is needed. */
495                                         goto out;
496                                 }
497                                 seen |= SEEN_DATAREF | SEEN_XREG;
498                                 t_offset = sk_load_byte_msh - (image + addrs[i]);
499                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi */
500                                 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
501                                 break;
502                         case BPF_S_LD_W_IND:
503                                 func = sk_load_word_ind;
504 common_load_ind:                seen |= SEEN_DATAREF | SEEN_XREG;
505                                 t_offset = func - (image + addrs[i]);
506                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi   */
507                                 EMIT1_off32(0xe8, t_offset);    /* call sk_load_xxx_ind */
508                                 break;
509                         case BPF_S_LD_H_IND:
510                                 func = sk_load_half_ind;
511                                 goto common_load_ind;
512                         case BPF_S_LD_B_IND:
513                                 func = sk_load_byte_ind;
514                                 goto common_load_ind;
515                         case BPF_S_JMP_JA:
516                                 t_offset = addrs[i + K] - addrs[i];
517                                 EMIT_JMP(t_offset);
518                                 break;
519                         COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
520                         COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
521                         COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
522                         COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
523                         COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
524                         COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
525                         COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
526                         COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
527
528 cond_branch:                    f_offset = addrs[i + filter[i].jf] - addrs[i];
529                                 t_offset = addrs[i + filter[i].jt] - addrs[i];
530
531                                 /* same targets, can avoid doing the test :) */
532                                 if (filter[i].jt == filter[i].jf) {
533                                         EMIT_JMP(t_offset);
534                                         break;
535                                 }
536
537                                 switch (filter[i].code) {
538                                 case BPF_S_JMP_JGT_X:
539                                 case BPF_S_JMP_JGE_X:
540                                 case BPF_S_JMP_JEQ_X:
541                                         seen |= SEEN_XREG;
542                                         EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
543                                         break;
544                                 case BPF_S_JMP_JSET_X:
545                                         seen |= SEEN_XREG;
546                                         EMIT2(0x85, 0xd8); /* test %ebx,%eax */
547                                         break;
548                                 case BPF_S_JMP_JEQ_K:
549                                         if (K == 0) {
550                                                 EMIT2(0x85, 0xc0); /* test   %eax,%eax */
551                                                 break;
552                                         }
553                                 case BPF_S_JMP_JGT_K:
554                                 case BPF_S_JMP_JGE_K:
555                                         if (K <= 127)
556                                                 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
557                                         else
558                                                 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
559                                         break;
560                                 case BPF_S_JMP_JSET_K:
561                                         if (K <= 0xFF)
562                                                 EMIT2(0xa8, K); /* test imm8,%al */
563                                         else if (!(K & 0xFFFF00FF))
564                                                 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
565                                         else if (K <= 0xFFFF) {
566                                                 EMIT2(0x66, 0xa9); /* test imm16,%ax */
567                                                 EMIT(K, 2);
568                                         } else {
569                                                 EMIT1_off32(0xa9, K); /* test imm32,%eax */
570                                         }
571                                         break;
572                                 }
573                                 if (filter[i].jt != 0) {
574                                         if (filter[i].jf && f_offset)
575                                                 t_offset += is_near(f_offset) ? 2 : 5;
576                                         EMIT_COND_JMP(t_op, t_offset);
577                                         if (filter[i].jf)
578                                                 EMIT_JMP(f_offset);
579                                         break;
580                                 }
581                                 EMIT_COND_JMP(f_op, f_offset);
582                                 break;
583                         default:
584                                 /* hmm, too complex filter, give up with jit compiler */
585                                 goto out;
586                         }
587                         ilen = prog - temp;
588                         if (image) {
589                                 if (unlikely(proglen + ilen > oldproglen)) {
590                                         pr_err("bpb_jit_compile fatal error\n");
591                                         kfree(addrs);
592                                         module_free(NULL, image);
593                                         return;
594                                 }
595                                 memcpy(image + proglen, temp, ilen);
596                         }
597                         proglen += ilen;
598                         addrs[i] = proglen;
599                         prog = temp;
600                 }
601                 /* last bpf instruction is always a RET :
602                  * use it to give the cleanup instruction(s) addr
603                  */
604                 cleanup_addr = proglen - 1; /* ret */
605                 if (seen_or_pass0)
606                         cleanup_addr -= 1; /* leaveq */
607                 if (seen_or_pass0 & SEEN_XREG)
608                         cleanup_addr -= 4; /* mov  -8(%rbp),%rbx */
609
610                 if (image) {
611                         if (proglen != oldproglen)
612                                 pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
613                         break;
614                 }
615                 if (proglen == oldproglen) {
616                         image = module_alloc(max_t(unsigned int,
617                                                    proglen,
618                                                    sizeof(struct work_struct)));
619                         if (!image)
620                                 goto out;
621                 }
622                 oldproglen = proglen;
623         }
624         if (bpf_jit_enable > 1)
625                 pr_err("flen=%d proglen=%u pass=%d image=%p\n",
626                        flen, proglen, pass, image);
627
628         if (image) {
629                 if (bpf_jit_enable > 1)
630                         print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS,
631                                        16, 1, image, proglen, false);
632
633                 bpf_flush_icache(image, image + proglen);
634
635                 fp->bpf_func = (void *)image;
636         }
637 out:
638         kfree(addrs);
639         return;
640 }
641
642 static void jit_free_defer(struct work_struct *arg)
643 {
644         module_free(NULL, arg);
645 }
646
647 /* run from softirq, we must use a work_struct to call
648  * module_free() from process context
649  */
650 void bpf_jit_free(struct sk_filter *fp)
651 {
652         if (fp->bpf_func != sk_run_filter) {
653                 struct work_struct *work = (struct work_struct *)fp->bpf_func;
654
655                 INIT_WORK(work, jit_free_defer);
656                 schedule_work(work);
657         }
658 }