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0a14842f ED |
1 | /* bpf_jit_comp.c : BPF JIT compiler |
2 | * | |
3b58908a | 3 | * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com) |
62258278 | 4 | * Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
0a14842f ED |
5 | * |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; version 2 | |
9 | * of the License. | |
10 | */ | |
0a14842f ED |
11 | #include <linux/netdevice.h> |
12 | #include <linux/filter.h> | |
855ddb56 | 13 | #include <linux/if_vlan.h> |
738cbe72 | 14 | #include <asm/cacheflush.h> |
b52f00e6 | 15 | #include <linux/bpf.h> |
0a14842f | 16 | |
0a14842f ED |
17 | int bpf_jit_enable __read_mostly; |
18 | ||
19 | /* | |
20 | * assembly code in arch/x86/net/bpf_jit.S | |
21 | */ | |
62258278 | 22 | extern u8 sk_load_word[], sk_load_half[], sk_load_byte[]; |
a998d434 | 23 | extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[]; |
62258278 | 24 | extern u8 sk_load_byte_positive_offset[]; |
a998d434 | 25 | extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[]; |
62258278 | 26 | extern u8 sk_load_byte_negative_offset[]; |
0a14842f | 27 | |
5cccc702 | 28 | static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) |
0a14842f ED |
29 | { |
30 | if (len == 1) | |
31 | *ptr = bytes; | |
32 | else if (len == 2) | |
33 | *(u16 *)ptr = bytes; | |
34 | else { | |
35 | *(u32 *)ptr = bytes; | |
36 | barrier(); | |
37 | } | |
38 | return ptr + len; | |
39 | } | |
40 | ||
b52f00e6 AS |
41 | #define EMIT(bytes, len) \ |
42 | do { prog = emit_code(prog, bytes, len); cnt += len; } while (0) | |
0a14842f ED |
43 | |
44 | #define EMIT1(b1) EMIT(b1, 1) | |
45 | #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2) | |
46 | #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3) | |
47 | #define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4) | |
62258278 AS |
48 | #define EMIT1_off32(b1, off) \ |
49 | do {EMIT1(b1); EMIT(off, 4); } while (0) | |
50 | #define EMIT2_off32(b1, b2, off) \ | |
51 | do {EMIT2(b1, b2); EMIT(off, 4); } while (0) | |
52 | #define EMIT3_off32(b1, b2, b3, off) \ | |
53 | do {EMIT3(b1, b2, b3); EMIT(off, 4); } while (0) | |
54 | #define EMIT4_off32(b1, b2, b3, b4, off) \ | |
55 | do {EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0) | |
0a14842f | 56 | |
5cccc702 | 57 | static bool is_imm8(int value) |
0a14842f ED |
58 | { |
59 | return value <= 127 && value >= -128; | |
60 | } | |
61 | ||
5cccc702 | 62 | static bool is_simm32(s64 value) |
0a14842f | 63 | { |
62258278 | 64 | return value == (s64) (s32) value; |
0a14842f ED |
65 | } |
66 | ||
e430f34e AS |
67 | /* mov dst, src */ |
68 | #define EMIT_mov(DST, SRC) \ | |
69 | do {if (DST != SRC) \ | |
70 | EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \ | |
62258278 AS |
71 | } while (0) |
72 | ||
73 | static int bpf_size_to_x86_bytes(int bpf_size) | |
74 | { | |
75 | if (bpf_size == BPF_W) | |
76 | return 4; | |
77 | else if (bpf_size == BPF_H) | |
78 | return 2; | |
79 | else if (bpf_size == BPF_B) | |
80 | return 1; | |
81 | else if (bpf_size == BPF_DW) | |
82 | return 4; /* imm32 */ | |
83 | else | |
84 | return 0; | |
85 | } | |
0a14842f ED |
86 | |
87 | /* list of x86 cond jumps opcodes (. + s8) | |
88 | * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32) | |
89 | */ | |
90 | #define X86_JB 0x72 | |
91 | #define X86_JAE 0x73 | |
92 | #define X86_JE 0x74 | |
93 | #define X86_JNE 0x75 | |
94 | #define X86_JBE 0x76 | |
95 | #define X86_JA 0x77 | |
62258278 AS |
96 | #define X86_JGE 0x7D |
97 | #define X86_JG 0x7F | |
0a14842f | 98 | |
5cccc702 | 99 | static void bpf_flush_icache(void *start, void *end) |
0a14842f ED |
100 | { |
101 | mm_segment_t old_fs = get_fs(); | |
102 | ||
103 | set_fs(KERNEL_DS); | |
104 | smp_wmb(); | |
105 | flush_icache_range((unsigned long)start, (unsigned long)end); | |
106 | set_fs(old_fs); | |
107 | } | |
108 | ||
a998d434 JS |
109 | #define CHOOSE_LOAD_FUNC(K, func) \ |
110 | ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset) | |
0a14842f | 111 | |
62258278 AS |
112 | /* pick a register outside of BPF range for JIT internal work */ |
113 | #define AUX_REG (MAX_BPF_REG + 1) | |
114 | ||
115 | /* the following table maps BPF registers to x64 registers. | |
116 | * x64 register r12 is unused, since if used as base address register | |
117 | * in load/store instructions, it always needs an extra byte of encoding | |
118 | */ | |
119 | static const int reg2hex[] = { | |
120 | [BPF_REG_0] = 0, /* rax */ | |
121 | [BPF_REG_1] = 7, /* rdi */ | |
122 | [BPF_REG_2] = 6, /* rsi */ | |
123 | [BPF_REG_3] = 2, /* rdx */ | |
124 | [BPF_REG_4] = 1, /* rcx */ | |
125 | [BPF_REG_5] = 0, /* r8 */ | |
126 | [BPF_REG_6] = 3, /* rbx callee saved */ | |
127 | [BPF_REG_7] = 5, /* r13 callee saved */ | |
128 | [BPF_REG_8] = 6, /* r14 callee saved */ | |
129 | [BPF_REG_9] = 7, /* r15 callee saved */ | |
130 | [BPF_REG_FP] = 5, /* rbp readonly */ | |
131 | [AUX_REG] = 3, /* r11 temp register */ | |
132 | }; | |
133 | ||
134 | /* is_ereg() == true if BPF register 'reg' maps to x64 r8..r15 | |
135 | * which need extra byte of encoding. | |
136 | * rax,rcx,...,rbp have simpler encoding | |
137 | */ | |
5cccc702 | 138 | static bool is_ereg(u32 reg) |
62258278 | 139 | { |
d148134b JP |
140 | return (1 << reg) & (BIT(BPF_REG_5) | |
141 | BIT(AUX_REG) | | |
142 | BIT(BPF_REG_7) | | |
143 | BIT(BPF_REG_8) | | |
144 | BIT(BPF_REG_9)); | |
62258278 AS |
145 | } |
146 | ||
147 | /* add modifiers if 'reg' maps to x64 registers r8..r15 */ | |
5cccc702 | 148 | static u8 add_1mod(u8 byte, u32 reg) |
62258278 AS |
149 | { |
150 | if (is_ereg(reg)) | |
151 | byte |= 1; | |
152 | return byte; | |
153 | } | |
154 | ||
5cccc702 | 155 | static u8 add_2mod(u8 byte, u32 r1, u32 r2) |
62258278 AS |
156 | { |
157 | if (is_ereg(r1)) | |
158 | byte |= 1; | |
159 | if (is_ereg(r2)) | |
160 | byte |= 4; | |
161 | return byte; | |
162 | } | |
163 | ||
e430f34e | 164 | /* encode 'dst_reg' register into x64 opcode 'byte' */ |
5cccc702 | 165 | static u8 add_1reg(u8 byte, u32 dst_reg) |
62258278 | 166 | { |
e430f34e | 167 | return byte + reg2hex[dst_reg]; |
62258278 AS |
168 | } |
169 | ||
e430f34e | 170 | /* encode 'dst_reg' and 'src_reg' registers into x64 opcode 'byte' */ |
5cccc702 | 171 | static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg) |
62258278 | 172 | { |
e430f34e | 173 | return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3); |
62258278 AS |
174 | } |
175 | ||
738cbe72 DB |
176 | static void jit_fill_hole(void *area, unsigned int size) |
177 | { | |
178 | /* fill whole space with int3 instructions */ | |
179 | memset(area, 0xcc, size); | |
180 | } | |
181 | ||
f3c2af7b | 182 | struct jit_context { |
769e0de6 | 183 | int cleanup_addr; /* epilogue code offset */ |
62258278 | 184 | bool seen_ld_abs; |
f3c2af7b AS |
185 | }; |
186 | ||
e0ee9c12 AS |
187 | /* maximum number of bytes emitted while JITing one eBPF insn */ |
188 | #define BPF_MAX_INSN_SIZE 128 | |
189 | #define BPF_INSN_SAFETY 64 | |
190 | ||
b52f00e6 AS |
191 | #define STACKSIZE \ |
192 | (MAX_BPF_STACK + \ | |
193 | 32 /* space for rbx, r13, r14, r15 */ + \ | |
194 | 8 /* space for skb_copy_bits() buffer */) | |
195 | ||
196 | #define PROLOGUE_SIZE 51 | |
197 | ||
198 | /* emit x64 prologue code for BPF program and check it's size. | |
199 | * bpf_tail_call helper will skip it while jumping into another program | |
200 | */ | |
201 | static void emit_prologue(u8 **pprog) | |
0a14842f | 202 | { |
b52f00e6 AS |
203 | u8 *prog = *pprog; |
204 | int cnt = 0; | |
0a14842f | 205 | |
62258278 AS |
206 | EMIT1(0x55); /* push rbp */ |
207 | EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */ | |
0a14842f | 208 | |
b52f00e6 AS |
209 | /* sub rsp, STACKSIZE */ |
210 | EMIT3_off32(0x48, 0x81, 0xEC, STACKSIZE); | |
62258278 AS |
211 | |
212 | /* all classic BPF filters use R6(rbx) save it */ | |
213 | ||
214 | /* mov qword ptr [rbp-X],rbx */ | |
b52f00e6 | 215 | EMIT3_off32(0x48, 0x89, 0x9D, -STACKSIZE); |
62258278 | 216 | |
8fb575ca | 217 | /* bpf_convert_filter() maps classic BPF register X to R7 and uses R8 |
62258278 AS |
218 | * as temporary, so all tcpdump filters need to spill/fill R7(r13) and |
219 | * R8(r14). R9(r15) spill could be made conditional, but there is only | |
220 | * one 'bpf_error' return path out of helper functions inside bpf_jit.S | |
221 | * The overhead of extra spill is negligible for any filter other | |
222 | * than synthetic ones. Therefore not worth adding complexity. | |
223 | */ | |
224 | ||
225 | /* mov qword ptr [rbp-X],r13 */ | |
b52f00e6 | 226 | EMIT3_off32(0x4C, 0x89, 0xAD, -STACKSIZE + 8); |
62258278 | 227 | /* mov qword ptr [rbp-X],r14 */ |
b52f00e6 | 228 | EMIT3_off32(0x4C, 0x89, 0xB5, -STACKSIZE + 16); |
62258278 | 229 | /* mov qword ptr [rbp-X],r15 */ |
b52f00e6 | 230 | EMIT3_off32(0x4C, 0x89, 0xBD, -STACKSIZE + 24); |
62258278 AS |
231 | |
232 | /* clear A and X registers */ | |
233 | EMIT2(0x31, 0xc0); /* xor eax, eax */ | |
234 | EMIT3(0x4D, 0x31, 0xED); /* xor r13, r13 */ | |
235 | ||
b52f00e6 AS |
236 | /* clear tail_cnt: mov qword ptr [rbp-X], rax */ |
237 | EMIT3_off32(0x48, 0x89, 0x85, -STACKSIZE + 32); | |
238 | ||
239 | BUILD_BUG_ON(cnt != PROLOGUE_SIZE); | |
240 | *pprog = prog; | |
241 | } | |
242 | ||
243 | /* generate the following code: | |
244 | * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ... | |
245 | * if (index >= array->map.max_entries) | |
246 | * goto out; | |
247 | * if (++tail_call_cnt > MAX_TAIL_CALL_CNT) | |
248 | * goto out; | |
2a36f0b9 | 249 | * prog = array->ptrs[index]; |
b52f00e6 AS |
250 | * if (prog == NULL) |
251 | * goto out; | |
252 | * goto *(prog->bpf_func + prologue_size); | |
253 | * out: | |
254 | */ | |
255 | static void emit_bpf_tail_call(u8 **pprog) | |
256 | { | |
257 | u8 *prog = *pprog; | |
258 | int label1, label2, label3; | |
259 | int cnt = 0; | |
260 | ||
261 | /* rdi - pointer to ctx | |
262 | * rsi - pointer to bpf_array | |
263 | * rdx - index in bpf_array | |
264 | */ | |
265 | ||
266 | /* if (index >= array->map.max_entries) | |
267 | * goto out; | |
268 | */ | |
269 | EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */ | |
270 | offsetof(struct bpf_array, map.max_entries)); | |
271 | EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */ | |
2482abb9 | 272 | #define OFFSET1 47 /* number of bytes to jump */ |
b52f00e6 AS |
273 | EMIT2(X86_JBE, OFFSET1); /* jbe out */ |
274 | label1 = cnt; | |
275 | ||
276 | /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) | |
277 | * goto out; | |
278 | */ | |
279 | EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */ | |
280 | EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */ | |
2482abb9 | 281 | #define OFFSET2 36 |
b52f00e6 AS |
282 | EMIT2(X86_JA, OFFSET2); /* ja out */ |
283 | label2 = cnt; | |
284 | EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */ | |
285 | EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */ | |
286 | ||
2a36f0b9 | 287 | /* prog = array->ptrs[index]; */ |
2482abb9 | 288 | EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */ |
2a36f0b9 | 289 | offsetof(struct bpf_array, ptrs)); |
b52f00e6 AS |
290 | EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */ |
291 | ||
292 | /* if (prog == NULL) | |
293 | * goto out; | |
294 | */ | |
295 | EMIT4(0x48, 0x83, 0xF8, 0x00); /* cmp rax, 0 */ | |
296 | #define OFFSET3 10 | |
297 | EMIT2(X86_JE, OFFSET3); /* je out */ | |
298 | label3 = cnt; | |
299 | ||
300 | /* goto *(prog->bpf_func + prologue_size); */ | |
301 | EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */ | |
302 | offsetof(struct bpf_prog, bpf_func)); | |
303 | EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */ | |
304 | ||
305 | /* now we're ready to jump into next BPF program | |
306 | * rdi == ctx (1st arg) | |
307 | * rax == prog->bpf_func + prologue_size | |
308 | */ | |
309 | EMIT2(0xFF, 0xE0); /* jmp rax */ | |
310 | ||
311 | /* out: */ | |
312 | BUILD_BUG_ON(cnt - label1 != OFFSET1); | |
313 | BUILD_BUG_ON(cnt - label2 != OFFSET2); | |
314 | BUILD_BUG_ON(cnt - label3 != OFFSET3); | |
315 | *pprog = prog; | |
316 | } | |
317 | ||
4e10df9a AS |
318 | |
319 | static void emit_load_skb_data_hlen(u8 **pprog) | |
320 | { | |
321 | u8 *prog = *pprog; | |
322 | int cnt = 0; | |
323 | ||
324 | /* r9d = skb->len - skb->data_len (headlen) | |
325 | * r10 = skb->data | |
326 | */ | |
327 | /* mov %r9d, off32(%rdi) */ | |
328 | EMIT3_off32(0x44, 0x8b, 0x8f, offsetof(struct sk_buff, len)); | |
329 | ||
330 | /* sub %r9d, off32(%rdi) */ | |
331 | EMIT3_off32(0x44, 0x2b, 0x8f, offsetof(struct sk_buff, data_len)); | |
332 | ||
333 | /* mov %r10, off32(%rdi) */ | |
334 | EMIT3_off32(0x4c, 0x8b, 0x97, offsetof(struct sk_buff, data)); | |
335 | *pprog = prog; | |
336 | } | |
337 | ||
b52f00e6 AS |
338 | static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, |
339 | int oldproglen, struct jit_context *ctx) | |
340 | { | |
341 | struct bpf_insn *insn = bpf_prog->insnsi; | |
342 | int insn_cnt = bpf_prog->len; | |
343 | bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0); | |
344 | bool seen_exit = false; | |
345 | u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY]; | |
346 | int i, cnt = 0; | |
347 | int proglen = 0; | |
348 | u8 *prog = temp; | |
349 | ||
350 | emit_prologue(&prog); | |
351 | ||
4e10df9a AS |
352 | if (seen_ld_abs) |
353 | emit_load_skb_data_hlen(&prog); | |
62258278 AS |
354 | |
355 | for (i = 0; i < insn_cnt; i++, insn++) { | |
e430f34e AS |
356 | const s32 imm32 = insn->imm; |
357 | u32 dst_reg = insn->dst_reg; | |
358 | u32 src_reg = insn->src_reg; | |
62258278 AS |
359 | u8 b1 = 0, b2 = 0, b3 = 0; |
360 | s64 jmp_offset; | |
361 | u8 jmp_cond; | |
4e10df9a | 362 | bool reload_skb_data; |
62258278 AS |
363 | int ilen; |
364 | u8 *func; | |
365 | ||
366 | switch (insn->code) { | |
367 | /* ALU */ | |
368 | case BPF_ALU | BPF_ADD | BPF_X: | |
369 | case BPF_ALU | BPF_SUB | BPF_X: | |
370 | case BPF_ALU | BPF_AND | BPF_X: | |
371 | case BPF_ALU | BPF_OR | BPF_X: | |
372 | case BPF_ALU | BPF_XOR | BPF_X: | |
373 | case BPF_ALU64 | BPF_ADD | BPF_X: | |
374 | case BPF_ALU64 | BPF_SUB | BPF_X: | |
375 | case BPF_ALU64 | BPF_AND | BPF_X: | |
376 | case BPF_ALU64 | BPF_OR | BPF_X: | |
377 | case BPF_ALU64 | BPF_XOR | BPF_X: | |
378 | switch (BPF_OP(insn->code)) { | |
379 | case BPF_ADD: b2 = 0x01; break; | |
380 | case BPF_SUB: b2 = 0x29; break; | |
381 | case BPF_AND: b2 = 0x21; break; | |
382 | case BPF_OR: b2 = 0x09; break; | |
383 | case BPF_XOR: b2 = 0x31; break; | |
0a14842f | 384 | } |
62258278 | 385 | if (BPF_CLASS(insn->code) == BPF_ALU64) |
e430f34e AS |
386 | EMIT1(add_2mod(0x48, dst_reg, src_reg)); |
387 | else if (is_ereg(dst_reg) || is_ereg(src_reg)) | |
388 | EMIT1(add_2mod(0x40, dst_reg, src_reg)); | |
389 | EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg)); | |
62258278 | 390 | break; |
0a14842f | 391 | |
e430f34e | 392 | /* mov dst, src */ |
62258278 | 393 | case BPF_ALU64 | BPF_MOV | BPF_X: |
e430f34e | 394 | EMIT_mov(dst_reg, src_reg); |
0a14842f | 395 | break; |
0a14842f | 396 | |
e430f34e | 397 | /* mov32 dst, src */ |
62258278 | 398 | case BPF_ALU | BPF_MOV | BPF_X: |
e430f34e AS |
399 | if (is_ereg(dst_reg) || is_ereg(src_reg)) |
400 | EMIT1(add_2mod(0x40, dst_reg, src_reg)); | |
401 | EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg)); | |
62258278 | 402 | break; |
0a14842f | 403 | |
e430f34e | 404 | /* neg dst */ |
62258278 AS |
405 | case BPF_ALU | BPF_NEG: |
406 | case BPF_ALU64 | BPF_NEG: | |
407 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
e430f34e AS |
408 | EMIT1(add_1mod(0x48, dst_reg)); |
409 | else if (is_ereg(dst_reg)) | |
410 | EMIT1(add_1mod(0x40, dst_reg)); | |
411 | EMIT2(0xF7, add_1reg(0xD8, dst_reg)); | |
62258278 AS |
412 | break; |
413 | ||
414 | case BPF_ALU | BPF_ADD | BPF_K: | |
415 | case BPF_ALU | BPF_SUB | BPF_K: | |
416 | case BPF_ALU | BPF_AND | BPF_K: | |
417 | case BPF_ALU | BPF_OR | BPF_K: | |
418 | case BPF_ALU | BPF_XOR | BPF_K: | |
419 | case BPF_ALU64 | BPF_ADD | BPF_K: | |
420 | case BPF_ALU64 | BPF_SUB | BPF_K: | |
421 | case BPF_ALU64 | BPF_AND | BPF_K: | |
422 | case BPF_ALU64 | BPF_OR | BPF_K: | |
423 | case BPF_ALU64 | BPF_XOR | BPF_K: | |
424 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
e430f34e AS |
425 | EMIT1(add_1mod(0x48, dst_reg)); |
426 | else if (is_ereg(dst_reg)) | |
427 | EMIT1(add_1mod(0x40, dst_reg)); | |
62258278 AS |
428 | |
429 | switch (BPF_OP(insn->code)) { | |
430 | case BPF_ADD: b3 = 0xC0; break; | |
431 | case BPF_SUB: b3 = 0xE8; break; | |
432 | case BPF_AND: b3 = 0xE0; break; | |
433 | case BPF_OR: b3 = 0xC8; break; | |
434 | case BPF_XOR: b3 = 0xF0; break; | |
435 | } | |
436 | ||
e430f34e AS |
437 | if (is_imm8(imm32)) |
438 | EMIT3(0x83, add_1reg(b3, dst_reg), imm32); | |
62258278 | 439 | else |
e430f34e | 440 | EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32); |
62258278 AS |
441 | break; |
442 | ||
443 | case BPF_ALU64 | BPF_MOV | BPF_K: | |
444 | /* optimization: if imm32 is positive, | |
445 | * use 'mov eax, imm32' (which zero-extends imm32) | |
446 | * to save 2 bytes | |
447 | */ | |
e430f34e | 448 | if (imm32 < 0) { |
62258278 | 449 | /* 'mov rax, imm32' sign extends imm32 */ |
e430f34e | 450 | b1 = add_1mod(0x48, dst_reg); |
62258278 AS |
451 | b2 = 0xC7; |
452 | b3 = 0xC0; | |
e430f34e | 453 | EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32); |
0a14842f | 454 | break; |
62258278 AS |
455 | } |
456 | ||
457 | case BPF_ALU | BPF_MOV | BPF_K: | |
458 | /* mov %eax, imm32 */ | |
e430f34e AS |
459 | if (is_ereg(dst_reg)) |
460 | EMIT1(add_1mod(0x40, dst_reg)); | |
461 | EMIT1_off32(add_1reg(0xB8, dst_reg), imm32); | |
62258278 AS |
462 | break; |
463 | ||
02ab695b AS |
464 | case BPF_LD | BPF_IMM | BPF_DW: |
465 | if (insn[1].code != 0 || insn[1].src_reg != 0 || | |
466 | insn[1].dst_reg != 0 || insn[1].off != 0) { | |
467 | /* verifier must catch invalid insns */ | |
468 | pr_err("invalid BPF_LD_IMM64 insn\n"); | |
469 | return -EINVAL; | |
470 | } | |
471 | ||
472 | /* movabsq %rax, imm64 */ | |
473 | EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg)); | |
474 | EMIT(insn[0].imm, 4); | |
475 | EMIT(insn[1].imm, 4); | |
476 | ||
477 | insn++; | |
478 | i++; | |
479 | break; | |
480 | ||
e430f34e | 481 | /* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */ |
62258278 AS |
482 | case BPF_ALU | BPF_MOD | BPF_X: |
483 | case BPF_ALU | BPF_DIV | BPF_X: | |
484 | case BPF_ALU | BPF_MOD | BPF_K: | |
485 | case BPF_ALU | BPF_DIV | BPF_K: | |
486 | case BPF_ALU64 | BPF_MOD | BPF_X: | |
487 | case BPF_ALU64 | BPF_DIV | BPF_X: | |
488 | case BPF_ALU64 | BPF_MOD | BPF_K: | |
489 | case BPF_ALU64 | BPF_DIV | BPF_K: | |
490 | EMIT1(0x50); /* push rax */ | |
491 | EMIT1(0x52); /* push rdx */ | |
492 | ||
493 | if (BPF_SRC(insn->code) == BPF_X) | |
e430f34e AS |
494 | /* mov r11, src_reg */ |
495 | EMIT_mov(AUX_REG, src_reg); | |
62258278 | 496 | else |
e430f34e AS |
497 | /* mov r11, imm32 */ |
498 | EMIT3_off32(0x49, 0xC7, 0xC3, imm32); | |
62258278 | 499 | |
e430f34e AS |
500 | /* mov rax, dst_reg */ |
501 | EMIT_mov(BPF_REG_0, dst_reg); | |
62258278 AS |
502 | |
503 | /* xor edx, edx | |
504 | * equivalent to 'xor rdx, rdx', but one byte less | |
505 | */ | |
506 | EMIT2(0x31, 0xd2); | |
507 | ||
508 | if (BPF_SRC(insn->code) == BPF_X) { | |
e430f34e | 509 | /* if (src_reg == 0) return 0 */ |
62258278 AS |
510 | |
511 | /* cmp r11, 0 */ | |
512 | EMIT4(0x49, 0x83, 0xFB, 0x00); | |
513 | ||
514 | /* jne .+9 (skip over pop, pop, xor and jmp) */ | |
515 | EMIT2(X86_JNE, 1 + 1 + 2 + 5); | |
516 | EMIT1(0x5A); /* pop rdx */ | |
517 | EMIT1(0x58); /* pop rax */ | |
518 | EMIT2(0x31, 0xc0); /* xor eax, eax */ | |
519 | ||
520 | /* jmp cleanup_addr | |
521 | * addrs[i] - 11, because there are 11 bytes | |
522 | * after this insn: div, mov, pop, pop, mov | |
523 | */ | |
524 | jmp_offset = ctx->cleanup_addr - (addrs[i] - 11); | |
525 | EMIT1_off32(0xE9, jmp_offset); | |
526 | } | |
527 | ||
528 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
529 | /* div r11 */ | |
530 | EMIT3(0x49, 0xF7, 0xF3); | |
531 | else | |
532 | /* div r11d */ | |
533 | EMIT3(0x41, 0xF7, 0xF3); | |
534 | ||
535 | if (BPF_OP(insn->code) == BPF_MOD) | |
536 | /* mov r11, rdx */ | |
537 | EMIT3(0x49, 0x89, 0xD3); | |
538 | else | |
539 | /* mov r11, rax */ | |
540 | EMIT3(0x49, 0x89, 0xC3); | |
541 | ||
542 | EMIT1(0x5A); /* pop rdx */ | |
543 | EMIT1(0x58); /* pop rax */ | |
544 | ||
e430f34e AS |
545 | /* mov dst_reg, r11 */ |
546 | EMIT_mov(dst_reg, AUX_REG); | |
62258278 AS |
547 | break; |
548 | ||
549 | case BPF_ALU | BPF_MUL | BPF_K: | |
550 | case BPF_ALU | BPF_MUL | BPF_X: | |
551 | case BPF_ALU64 | BPF_MUL | BPF_K: | |
552 | case BPF_ALU64 | BPF_MUL | BPF_X: | |
553 | EMIT1(0x50); /* push rax */ | |
554 | EMIT1(0x52); /* push rdx */ | |
555 | ||
e430f34e AS |
556 | /* mov r11, dst_reg */ |
557 | EMIT_mov(AUX_REG, dst_reg); | |
62258278 AS |
558 | |
559 | if (BPF_SRC(insn->code) == BPF_X) | |
e430f34e AS |
560 | /* mov rax, src_reg */ |
561 | EMIT_mov(BPF_REG_0, src_reg); | |
62258278 | 562 | else |
e430f34e AS |
563 | /* mov rax, imm32 */ |
564 | EMIT3_off32(0x48, 0xC7, 0xC0, imm32); | |
62258278 AS |
565 | |
566 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
567 | EMIT1(add_1mod(0x48, AUX_REG)); | |
568 | else if (is_ereg(AUX_REG)) | |
569 | EMIT1(add_1mod(0x40, AUX_REG)); | |
570 | /* mul(q) r11 */ | |
571 | EMIT2(0xF7, add_1reg(0xE0, AUX_REG)); | |
572 | ||
573 | /* mov r11, rax */ | |
574 | EMIT_mov(AUX_REG, BPF_REG_0); | |
575 | ||
576 | EMIT1(0x5A); /* pop rdx */ | |
577 | EMIT1(0x58); /* pop rax */ | |
578 | ||
e430f34e AS |
579 | /* mov dst_reg, r11 */ |
580 | EMIT_mov(dst_reg, AUX_REG); | |
62258278 AS |
581 | break; |
582 | ||
583 | /* shifts */ | |
584 | case BPF_ALU | BPF_LSH | BPF_K: | |
585 | case BPF_ALU | BPF_RSH | BPF_K: | |
586 | case BPF_ALU | BPF_ARSH | BPF_K: | |
587 | case BPF_ALU64 | BPF_LSH | BPF_K: | |
588 | case BPF_ALU64 | BPF_RSH | BPF_K: | |
589 | case BPF_ALU64 | BPF_ARSH | BPF_K: | |
590 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
e430f34e AS |
591 | EMIT1(add_1mod(0x48, dst_reg)); |
592 | else if (is_ereg(dst_reg)) | |
593 | EMIT1(add_1mod(0x40, dst_reg)); | |
62258278 AS |
594 | |
595 | switch (BPF_OP(insn->code)) { | |
596 | case BPF_LSH: b3 = 0xE0; break; | |
597 | case BPF_RSH: b3 = 0xE8; break; | |
598 | case BPF_ARSH: b3 = 0xF8; break; | |
599 | } | |
e430f34e | 600 | EMIT3(0xC1, add_1reg(b3, dst_reg), imm32); |
62258278 AS |
601 | break; |
602 | ||
72b603ee AS |
603 | case BPF_ALU | BPF_LSH | BPF_X: |
604 | case BPF_ALU | BPF_RSH | BPF_X: | |
605 | case BPF_ALU | BPF_ARSH | BPF_X: | |
606 | case BPF_ALU64 | BPF_LSH | BPF_X: | |
607 | case BPF_ALU64 | BPF_RSH | BPF_X: | |
608 | case BPF_ALU64 | BPF_ARSH | BPF_X: | |
609 | ||
610 | /* check for bad case when dst_reg == rcx */ | |
611 | if (dst_reg == BPF_REG_4) { | |
612 | /* mov r11, dst_reg */ | |
613 | EMIT_mov(AUX_REG, dst_reg); | |
614 | dst_reg = AUX_REG; | |
615 | } | |
616 | ||
617 | if (src_reg != BPF_REG_4) { /* common case */ | |
618 | EMIT1(0x51); /* push rcx */ | |
619 | ||
620 | /* mov rcx, src_reg */ | |
621 | EMIT_mov(BPF_REG_4, src_reg); | |
622 | } | |
623 | ||
624 | /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */ | |
625 | if (BPF_CLASS(insn->code) == BPF_ALU64) | |
626 | EMIT1(add_1mod(0x48, dst_reg)); | |
627 | else if (is_ereg(dst_reg)) | |
628 | EMIT1(add_1mod(0x40, dst_reg)); | |
629 | ||
630 | switch (BPF_OP(insn->code)) { | |
631 | case BPF_LSH: b3 = 0xE0; break; | |
632 | case BPF_RSH: b3 = 0xE8; break; | |
633 | case BPF_ARSH: b3 = 0xF8; break; | |
634 | } | |
635 | EMIT2(0xD3, add_1reg(b3, dst_reg)); | |
636 | ||
637 | if (src_reg != BPF_REG_4) | |
638 | EMIT1(0x59); /* pop rcx */ | |
639 | ||
640 | if (insn->dst_reg == BPF_REG_4) | |
641 | /* mov dst_reg, r11 */ | |
642 | EMIT_mov(insn->dst_reg, AUX_REG); | |
643 | break; | |
644 | ||
62258278 | 645 | case BPF_ALU | BPF_END | BPF_FROM_BE: |
e430f34e | 646 | switch (imm32) { |
62258278 AS |
647 | case 16: |
648 | /* emit 'ror %ax, 8' to swap lower 2 bytes */ | |
649 | EMIT1(0x66); | |
e430f34e | 650 | if (is_ereg(dst_reg)) |
62258278 | 651 | EMIT1(0x41); |
e430f34e | 652 | EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8); |
343f845b AS |
653 | |
654 | /* emit 'movzwl eax, ax' */ | |
655 | if (is_ereg(dst_reg)) | |
656 | EMIT3(0x45, 0x0F, 0xB7); | |
657 | else | |
658 | EMIT2(0x0F, 0xB7); | |
659 | EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); | |
62258278 AS |
660 | break; |
661 | case 32: | |
662 | /* emit 'bswap eax' to swap lower 4 bytes */ | |
e430f34e | 663 | if (is_ereg(dst_reg)) |
62258278 | 664 | EMIT2(0x41, 0x0F); |
0a14842f | 665 | else |
62258278 | 666 | EMIT1(0x0F); |
e430f34e | 667 | EMIT1(add_1reg(0xC8, dst_reg)); |
0a14842f | 668 | break; |
62258278 AS |
669 | case 64: |
670 | /* emit 'bswap rax' to swap 8 bytes */ | |
e430f34e AS |
671 | EMIT3(add_1mod(0x48, dst_reg), 0x0F, |
672 | add_1reg(0xC8, dst_reg)); | |
3b58908a ED |
673 | break; |
674 | } | |
62258278 AS |
675 | break; |
676 | ||
677 | case BPF_ALU | BPF_END | BPF_FROM_LE: | |
343f845b AS |
678 | switch (imm32) { |
679 | case 16: | |
680 | /* emit 'movzwl eax, ax' to zero extend 16-bit | |
681 | * into 64 bit | |
682 | */ | |
683 | if (is_ereg(dst_reg)) | |
684 | EMIT3(0x45, 0x0F, 0xB7); | |
685 | else | |
686 | EMIT2(0x0F, 0xB7); | |
687 | EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); | |
688 | break; | |
689 | case 32: | |
690 | /* emit 'mov eax, eax' to clear upper 32-bits */ | |
691 | if (is_ereg(dst_reg)) | |
692 | EMIT1(0x45); | |
693 | EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg)); | |
694 | break; | |
695 | case 64: | |
696 | /* nop */ | |
697 | break; | |
698 | } | |
62258278 AS |
699 | break; |
700 | ||
e430f34e | 701 | /* ST: *(u8*)(dst_reg + off) = imm */ |
62258278 | 702 | case BPF_ST | BPF_MEM | BPF_B: |
e430f34e | 703 | if (is_ereg(dst_reg)) |
62258278 AS |
704 | EMIT2(0x41, 0xC6); |
705 | else | |
706 | EMIT1(0xC6); | |
707 | goto st; | |
708 | case BPF_ST | BPF_MEM | BPF_H: | |
e430f34e | 709 | if (is_ereg(dst_reg)) |
62258278 AS |
710 | EMIT3(0x66, 0x41, 0xC7); |
711 | else | |
712 | EMIT2(0x66, 0xC7); | |
713 | goto st; | |
714 | case BPF_ST | BPF_MEM | BPF_W: | |
e430f34e | 715 | if (is_ereg(dst_reg)) |
62258278 AS |
716 | EMIT2(0x41, 0xC7); |
717 | else | |
718 | EMIT1(0xC7); | |
719 | goto st; | |
720 | case BPF_ST | BPF_MEM | BPF_DW: | |
e430f34e | 721 | EMIT2(add_1mod(0x48, dst_reg), 0xC7); |
62258278 AS |
722 | |
723 | st: if (is_imm8(insn->off)) | |
e430f34e | 724 | EMIT2(add_1reg(0x40, dst_reg), insn->off); |
62258278 | 725 | else |
e430f34e | 726 | EMIT1_off32(add_1reg(0x80, dst_reg), insn->off); |
62258278 | 727 | |
e430f34e | 728 | EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code))); |
62258278 AS |
729 | break; |
730 | ||
e430f34e | 731 | /* STX: *(u8*)(dst_reg + off) = src_reg */ |
62258278 AS |
732 | case BPF_STX | BPF_MEM | BPF_B: |
733 | /* emit 'mov byte ptr [rax + off], al' */ | |
e430f34e | 734 | if (is_ereg(dst_reg) || is_ereg(src_reg) || |
62258278 | 735 | /* have to add extra byte for x86 SIL, DIL regs */ |
e430f34e AS |
736 | src_reg == BPF_REG_1 || src_reg == BPF_REG_2) |
737 | EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88); | |
62258278 AS |
738 | else |
739 | EMIT1(0x88); | |
740 | goto stx; | |
741 | case BPF_STX | BPF_MEM | BPF_H: | |
e430f34e AS |
742 | if (is_ereg(dst_reg) || is_ereg(src_reg)) |
743 | EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89); | |
62258278 AS |
744 | else |
745 | EMIT2(0x66, 0x89); | |
746 | goto stx; | |
747 | case BPF_STX | BPF_MEM | BPF_W: | |
e430f34e AS |
748 | if (is_ereg(dst_reg) || is_ereg(src_reg)) |
749 | EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89); | |
62258278 AS |
750 | else |
751 | EMIT1(0x89); | |
752 | goto stx; | |
753 | case BPF_STX | BPF_MEM | BPF_DW: | |
e430f34e | 754 | EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89); |
62258278 | 755 | stx: if (is_imm8(insn->off)) |
e430f34e | 756 | EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off); |
62258278 | 757 | else |
e430f34e | 758 | EMIT1_off32(add_2reg(0x80, dst_reg, src_reg), |
62258278 AS |
759 | insn->off); |
760 | break; | |
761 | ||
e430f34e | 762 | /* LDX: dst_reg = *(u8*)(src_reg + off) */ |
62258278 AS |
763 | case BPF_LDX | BPF_MEM | BPF_B: |
764 | /* emit 'movzx rax, byte ptr [rax + off]' */ | |
e430f34e | 765 | EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6); |
62258278 AS |
766 | goto ldx; |
767 | case BPF_LDX | BPF_MEM | BPF_H: | |
768 | /* emit 'movzx rax, word ptr [rax + off]' */ | |
e430f34e | 769 | EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7); |
62258278 AS |
770 | goto ldx; |
771 | case BPF_LDX | BPF_MEM | BPF_W: | |
772 | /* emit 'mov eax, dword ptr [rax+0x14]' */ | |
e430f34e AS |
773 | if (is_ereg(dst_reg) || is_ereg(src_reg)) |
774 | EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B); | |
62258278 AS |
775 | else |
776 | EMIT1(0x8B); | |
777 | goto ldx; | |
778 | case BPF_LDX | BPF_MEM | BPF_DW: | |
779 | /* emit 'mov rax, qword ptr [rax+0x14]' */ | |
e430f34e | 780 | EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B); |
62258278 AS |
781 | ldx: /* if insn->off == 0 we can save one extra byte, but |
782 | * special case of x86 r13 which always needs an offset | |
783 | * is not worth the hassle | |
784 | */ | |
785 | if (is_imm8(insn->off)) | |
e430f34e | 786 | EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off); |
62258278 | 787 | else |
e430f34e | 788 | EMIT1_off32(add_2reg(0x80, src_reg, dst_reg), |
62258278 AS |
789 | insn->off); |
790 | break; | |
791 | ||
e430f34e | 792 | /* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */ |
62258278 AS |
793 | case BPF_STX | BPF_XADD | BPF_W: |
794 | /* emit 'lock add dword ptr [rax + off], eax' */ | |
e430f34e AS |
795 | if (is_ereg(dst_reg) || is_ereg(src_reg)) |
796 | EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01); | |
62258278 AS |
797 | else |
798 | EMIT2(0xF0, 0x01); | |
799 | goto xadd; | |
800 | case BPF_STX | BPF_XADD | BPF_DW: | |
e430f34e | 801 | EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01); |
62258278 | 802 | xadd: if (is_imm8(insn->off)) |
e430f34e | 803 | EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off); |
62258278 | 804 | else |
e430f34e | 805 | EMIT1_off32(add_2reg(0x80, dst_reg, src_reg), |
62258278 AS |
806 | insn->off); |
807 | break; | |
808 | ||
809 | /* call */ | |
810 | case BPF_JMP | BPF_CALL: | |
e430f34e | 811 | func = (u8 *) __bpf_call_base + imm32; |
62258278 | 812 | jmp_offset = func - (image + addrs[i]); |
e0ee9c12 | 813 | if (seen_ld_abs) { |
4e10df9a AS |
814 | reload_skb_data = bpf_helper_changes_skb_data(func); |
815 | if (reload_skb_data) { | |
816 | EMIT1(0x57); /* push %rdi */ | |
817 | jmp_offset += 22; /* pop, mov, sub, mov */ | |
818 | } else { | |
819 | EMIT2(0x41, 0x52); /* push %r10 */ | |
820 | EMIT2(0x41, 0x51); /* push %r9 */ | |
821 | /* need to adjust jmp offset, since | |
822 | * pop %r9, pop %r10 take 4 bytes after call insn | |
823 | */ | |
824 | jmp_offset += 4; | |
825 | } | |
62258278 | 826 | } |
e430f34e | 827 | if (!imm32 || !is_simm32(jmp_offset)) { |
62258278 | 828 | pr_err("unsupported bpf func %d addr %p image %p\n", |
e430f34e | 829 | imm32, func, image); |
62258278 AS |
830 | return -EINVAL; |
831 | } | |
832 | EMIT1_off32(0xE8, jmp_offset); | |
e0ee9c12 | 833 | if (seen_ld_abs) { |
4e10df9a AS |
834 | if (reload_skb_data) { |
835 | EMIT1(0x5F); /* pop %rdi */ | |
836 | emit_load_skb_data_hlen(&prog); | |
837 | } else { | |
838 | EMIT2(0x41, 0x59); /* pop %r9 */ | |
839 | EMIT2(0x41, 0x5A); /* pop %r10 */ | |
840 | } | |
62258278 AS |
841 | } |
842 | break; | |
843 | ||
b52f00e6 AS |
844 | case BPF_JMP | BPF_CALL | BPF_X: |
845 | emit_bpf_tail_call(&prog); | |
846 | break; | |
847 | ||
62258278 AS |
848 | /* cond jump */ |
849 | case BPF_JMP | BPF_JEQ | BPF_X: | |
850 | case BPF_JMP | BPF_JNE | BPF_X: | |
851 | case BPF_JMP | BPF_JGT | BPF_X: | |
852 | case BPF_JMP | BPF_JGE | BPF_X: | |
853 | case BPF_JMP | BPF_JSGT | BPF_X: | |
854 | case BPF_JMP | BPF_JSGE | BPF_X: | |
e430f34e AS |
855 | /* cmp dst_reg, src_reg */ |
856 | EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x39, | |
857 | add_2reg(0xC0, dst_reg, src_reg)); | |
62258278 AS |
858 | goto emit_cond_jmp; |
859 | ||
860 | case BPF_JMP | BPF_JSET | BPF_X: | |
e430f34e AS |
861 | /* test dst_reg, src_reg */ |
862 | EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x85, | |
863 | add_2reg(0xC0, dst_reg, src_reg)); | |
62258278 AS |
864 | goto emit_cond_jmp; |
865 | ||
866 | case BPF_JMP | BPF_JSET | BPF_K: | |
e430f34e AS |
867 | /* test dst_reg, imm32 */ |
868 | EMIT1(add_1mod(0x48, dst_reg)); | |
869 | EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32); | |
62258278 AS |
870 | goto emit_cond_jmp; |
871 | ||
872 | case BPF_JMP | BPF_JEQ | BPF_K: | |
873 | case BPF_JMP | BPF_JNE | BPF_K: | |
874 | case BPF_JMP | BPF_JGT | BPF_K: | |
875 | case BPF_JMP | BPF_JGE | BPF_K: | |
876 | case BPF_JMP | BPF_JSGT | BPF_K: | |
877 | case BPF_JMP | BPF_JSGE | BPF_K: | |
e430f34e AS |
878 | /* cmp dst_reg, imm8/32 */ |
879 | EMIT1(add_1mod(0x48, dst_reg)); | |
62258278 | 880 | |
e430f34e AS |
881 | if (is_imm8(imm32)) |
882 | EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32); | |
62258278 | 883 | else |
e430f34e | 884 | EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32); |
62258278 AS |
885 | |
886 | emit_cond_jmp: /* convert BPF opcode to x86 */ | |
887 | switch (BPF_OP(insn->code)) { | |
888 | case BPF_JEQ: | |
889 | jmp_cond = X86_JE; | |
890 | break; | |
891 | case BPF_JSET: | |
892 | case BPF_JNE: | |
893 | jmp_cond = X86_JNE; | |
894 | break; | |
895 | case BPF_JGT: | |
896 | /* GT is unsigned '>', JA in x86 */ | |
897 | jmp_cond = X86_JA; | |
898 | break; | |
899 | case BPF_JGE: | |
900 | /* GE is unsigned '>=', JAE in x86 */ | |
901 | jmp_cond = X86_JAE; | |
902 | break; | |
903 | case BPF_JSGT: | |
904 | /* signed '>', GT in x86 */ | |
905 | jmp_cond = X86_JG; | |
906 | break; | |
907 | case BPF_JSGE: | |
908 | /* signed '>=', GE in x86 */ | |
909 | jmp_cond = X86_JGE; | |
910 | break; | |
911 | default: /* to silence gcc warning */ | |
912 | return -EFAULT; | |
913 | } | |
914 | jmp_offset = addrs[i + insn->off] - addrs[i]; | |
915 | if (is_imm8(jmp_offset)) { | |
916 | EMIT2(jmp_cond, jmp_offset); | |
917 | } else if (is_simm32(jmp_offset)) { | |
918 | EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset); | |
919 | } else { | |
920 | pr_err("cond_jmp gen bug %llx\n", jmp_offset); | |
921 | return -EFAULT; | |
922 | } | |
923 | ||
924 | break; | |
0a14842f | 925 | |
62258278 AS |
926 | case BPF_JMP | BPF_JA: |
927 | jmp_offset = addrs[i + insn->off] - addrs[i]; | |
928 | if (!jmp_offset) | |
929 | /* optimize out nop jumps */ | |
930 | break; | |
931 | emit_jmp: | |
932 | if (is_imm8(jmp_offset)) { | |
933 | EMIT2(0xEB, jmp_offset); | |
934 | } else if (is_simm32(jmp_offset)) { | |
935 | EMIT1_off32(0xE9, jmp_offset); | |
936 | } else { | |
937 | pr_err("jmp gen bug %llx\n", jmp_offset); | |
938 | return -EFAULT; | |
939 | } | |
940 | break; | |
941 | ||
942 | case BPF_LD | BPF_IND | BPF_W: | |
943 | func = sk_load_word; | |
944 | goto common_load; | |
945 | case BPF_LD | BPF_ABS | BPF_W: | |
e430f34e | 946 | func = CHOOSE_LOAD_FUNC(imm32, sk_load_word); |
e0ee9c12 AS |
947 | common_load: |
948 | ctx->seen_ld_abs = seen_ld_abs = true; | |
62258278 AS |
949 | jmp_offset = func - (image + addrs[i]); |
950 | if (!func || !is_simm32(jmp_offset)) { | |
951 | pr_err("unsupported bpf func %d addr %p image %p\n", | |
e430f34e | 952 | imm32, func, image); |
62258278 AS |
953 | return -EINVAL; |
954 | } | |
955 | if (BPF_MODE(insn->code) == BPF_ABS) { | |
956 | /* mov %esi, imm32 */ | |
e430f34e | 957 | EMIT1_off32(0xBE, imm32); |
62258278 | 958 | } else { |
e430f34e AS |
959 | /* mov %rsi, src_reg */ |
960 | EMIT_mov(BPF_REG_2, src_reg); | |
961 | if (imm32) { | |
962 | if (is_imm8(imm32)) | |
62258278 | 963 | /* add %esi, imm8 */ |
e430f34e | 964 | EMIT3(0x83, 0xC6, imm32); |
0a14842f | 965 | else |
62258278 | 966 | /* add %esi, imm32 */ |
e430f34e | 967 | EMIT2_off32(0x81, 0xC6, imm32); |
0a14842f | 968 | } |
62258278 AS |
969 | } |
970 | /* skb pointer is in R6 (%rbx), it will be copied into | |
971 | * %rdi if skb_copy_bits() call is necessary. | |
972 | * sk_load_* helpers also use %r10 and %r9d. | |
973 | * See bpf_jit.S | |
974 | */ | |
975 | EMIT1_off32(0xE8, jmp_offset); /* call */ | |
976 | break; | |
977 | ||
978 | case BPF_LD | BPF_IND | BPF_H: | |
979 | func = sk_load_half; | |
980 | goto common_load; | |
981 | case BPF_LD | BPF_ABS | BPF_H: | |
e430f34e | 982 | func = CHOOSE_LOAD_FUNC(imm32, sk_load_half); |
62258278 AS |
983 | goto common_load; |
984 | case BPF_LD | BPF_IND | BPF_B: | |
985 | func = sk_load_byte; | |
986 | goto common_load; | |
987 | case BPF_LD | BPF_ABS | BPF_B: | |
e430f34e | 988 | func = CHOOSE_LOAD_FUNC(imm32, sk_load_byte); |
62258278 AS |
989 | goto common_load; |
990 | ||
991 | case BPF_JMP | BPF_EXIT: | |
769e0de6 | 992 | if (seen_exit) { |
62258278 AS |
993 | jmp_offset = ctx->cleanup_addr - addrs[i]; |
994 | goto emit_jmp; | |
995 | } | |
769e0de6 | 996 | seen_exit = true; |
62258278 AS |
997 | /* update cleanup_addr */ |
998 | ctx->cleanup_addr = proglen; | |
999 | /* mov rbx, qword ptr [rbp-X] */ | |
b52f00e6 | 1000 | EMIT3_off32(0x48, 0x8B, 0x9D, -STACKSIZE); |
62258278 | 1001 | /* mov r13, qword ptr [rbp-X] */ |
b52f00e6 | 1002 | EMIT3_off32(0x4C, 0x8B, 0xAD, -STACKSIZE + 8); |
62258278 | 1003 | /* mov r14, qword ptr [rbp-X] */ |
b52f00e6 | 1004 | EMIT3_off32(0x4C, 0x8B, 0xB5, -STACKSIZE + 16); |
62258278 | 1005 | /* mov r15, qword ptr [rbp-X] */ |
b52f00e6 | 1006 | EMIT3_off32(0x4C, 0x8B, 0xBD, -STACKSIZE + 24); |
62258278 AS |
1007 | |
1008 | EMIT1(0xC9); /* leave */ | |
1009 | EMIT1(0xC3); /* ret */ | |
1010 | break; | |
1011 | ||
f3c2af7b | 1012 | default: |
62258278 AS |
1013 | /* By design x64 JIT should support all BPF instructions |
1014 | * This error will be seen if new instruction was added | |
1015 | * to interpreter, but not to JIT | |
7ae457c1 | 1016 | * or if there is junk in bpf_prog |
62258278 AS |
1017 | */ |
1018 | pr_err("bpf_jit: unknown opcode %02x\n", insn->code); | |
f3c2af7b AS |
1019 | return -EINVAL; |
1020 | } | |
62258278 | 1021 | |
f3c2af7b | 1022 | ilen = prog - temp; |
e0ee9c12 AS |
1023 | if (ilen > BPF_MAX_INSN_SIZE) { |
1024 | pr_err("bpf_jit_compile fatal insn size error\n"); | |
1025 | return -EFAULT; | |
1026 | } | |
1027 | ||
f3c2af7b AS |
1028 | if (image) { |
1029 | if (unlikely(proglen + ilen > oldproglen)) { | |
62258278 | 1030 | pr_err("bpf_jit_compile fatal error\n"); |
f3c2af7b | 1031 | return -EFAULT; |
0a14842f | 1032 | } |
f3c2af7b | 1033 | memcpy(image + proglen, temp, ilen); |
0a14842f | 1034 | } |
f3c2af7b AS |
1035 | proglen += ilen; |
1036 | addrs[i] = proglen; | |
1037 | prog = temp; | |
1038 | } | |
f3c2af7b AS |
1039 | return proglen; |
1040 | } | |
1041 | ||
7ae457c1 | 1042 | void bpf_jit_compile(struct bpf_prog *prog) |
62258278 AS |
1043 | { |
1044 | } | |
1045 | ||
7ae457c1 | 1046 | void bpf_int_jit_compile(struct bpf_prog *prog) |
f3c2af7b AS |
1047 | { |
1048 | struct bpf_binary_header *header = NULL; | |
1049 | int proglen, oldproglen = 0; | |
1050 | struct jit_context ctx = {}; | |
1051 | u8 *image = NULL; | |
1052 | int *addrs; | |
1053 | int pass; | |
1054 | int i; | |
1055 | ||
1056 | if (!bpf_jit_enable) | |
1057 | return; | |
0a14842f | 1058 | |
f3c2af7b AS |
1059 | if (!prog || !prog->len) |
1060 | return; | |
1061 | ||
1062 | addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL); | |
1063 | if (!addrs) | |
1064 | return; | |
1065 | ||
1066 | /* Before first pass, make a rough estimation of addrs[] | |
1067 | * each bpf instruction is translated to less than 64 bytes | |
1068 | */ | |
1069 | for (proglen = 0, i = 0; i < prog->len; i++) { | |
1070 | proglen += 64; | |
1071 | addrs[i] = proglen; | |
1072 | } | |
1073 | ctx.cleanup_addr = proglen; | |
f3c2af7b | 1074 | |
3f7352bf AS |
1075 | /* JITed image shrinks with every pass and the loop iterates |
1076 | * until the image stops shrinking. Very large bpf programs | |
1077 | * may converge on the last pass. In such case do one more | |
1078 | * pass to emit the final image | |
1079 | */ | |
1080 | for (pass = 0; pass < 10 || image; pass++) { | |
f3c2af7b AS |
1081 | proglen = do_jit(prog, addrs, image, oldproglen, &ctx); |
1082 | if (proglen <= 0) { | |
1083 | image = NULL; | |
1084 | if (header) | |
738cbe72 | 1085 | bpf_jit_binary_free(header); |
f3c2af7b AS |
1086 | goto out; |
1087 | } | |
0a14842f | 1088 | if (image) { |
e0ee9c12 | 1089 | if (proglen != oldproglen) { |
f3c2af7b AS |
1090 | pr_err("bpf_jit: proglen=%d != oldproglen=%d\n", |
1091 | proglen, oldproglen); | |
e0ee9c12 AS |
1092 | goto out; |
1093 | } | |
0a14842f ED |
1094 | break; |
1095 | } | |
1096 | if (proglen == oldproglen) { | |
738cbe72 DB |
1097 | header = bpf_jit_binary_alloc(proglen, &image, |
1098 | 1, jit_fill_hole); | |
314beb9b | 1099 | if (!header) |
0a14842f ED |
1100 | goto out; |
1101 | } | |
1102 | oldproglen = proglen; | |
1103 | } | |
79617801 | 1104 | |
0a14842f | 1105 | if (bpf_jit_enable > 1) |
485d6511 | 1106 | bpf_jit_dump(prog->len, proglen, pass + 1, image); |
0a14842f ED |
1107 | |
1108 | if (image) { | |
314beb9b ED |
1109 | bpf_flush_icache(header, image + proglen); |
1110 | set_memory_ro((unsigned long)header, header->pages); | |
f3c2af7b | 1111 | prog->bpf_func = (void *)image; |
286aad3c | 1112 | prog->jited = true; |
0a14842f ED |
1113 | } |
1114 | out: | |
1115 | kfree(addrs); | |
0a14842f ED |
1116 | } |
1117 | ||
60a3b225 | 1118 | void bpf_jit_free(struct bpf_prog *fp) |
d45ed4a4 | 1119 | { |
d45ed4a4 AS |
1120 | unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK; |
1121 | struct bpf_binary_header *header = (void *)addr; | |
1122 | ||
60a3b225 DB |
1123 | if (!fp->jited) |
1124 | goto free_filter; | |
1125 | ||
d45ed4a4 | 1126 | set_memory_rw(addr, header->pages); |
738cbe72 | 1127 | bpf_jit_binary_free(header); |
d45ed4a4 | 1128 | |
60a3b225 DB |
1129 | free_filter: |
1130 | bpf_prog_unlock_free(fp); | |
0a14842f | 1131 | } |