10a14842fSEric Dumazet /* bpf_jit_comp.c : BPF JIT compiler 20a14842fSEric Dumazet * 30a14842fSEric Dumazet * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com) 40a14842fSEric Dumazet * 50a14842fSEric Dumazet * This program is free software; you can redistribute it and/or 60a14842fSEric Dumazet * modify it under the terms of the GNU General Public License 70a14842fSEric Dumazet * as published by the Free Software Foundation; version 2 80a14842fSEric Dumazet * of the License. 90a14842fSEric Dumazet */ 100a14842fSEric Dumazet #include <linux/moduleloader.h> 110a14842fSEric Dumazet #include <asm/cacheflush.h> 120a14842fSEric Dumazet #include <linux/netdevice.h> 130a14842fSEric Dumazet #include <linux/filter.h> 140a14842fSEric Dumazet 150a14842fSEric Dumazet /* 160a14842fSEric Dumazet * Conventions : 170a14842fSEric Dumazet * EAX : BPF A accumulator 180a14842fSEric Dumazet * EBX : BPF X accumulator 190a14842fSEric Dumazet * RDI : pointer to skb (first argument given to JIT function) 200a14842fSEric Dumazet * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n) 210a14842fSEric Dumazet * ECX,EDX,ESI : scratch registers 220a14842fSEric Dumazet * r9d : skb->len - skb->data_len (headlen) 230a14842fSEric Dumazet * r8 : skb->data 240a14842fSEric Dumazet * -8(RBP) : saved RBX value 250a14842fSEric Dumazet * -16(RBP)..-80(RBP) : BPF_MEMWORDS values 260a14842fSEric Dumazet */ 270a14842fSEric Dumazet int bpf_jit_enable __read_mostly; 280a14842fSEric Dumazet 290a14842fSEric Dumazet /* 300a14842fSEric Dumazet * assembly code in arch/x86/net/bpf_jit.S 310a14842fSEric Dumazet */ 320a14842fSEric Dumazet extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[]; 330a14842fSEric Dumazet extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[]; 340a14842fSEric Dumazet 350a14842fSEric Dumazet static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) 360a14842fSEric Dumazet { 370a14842fSEric Dumazet if (len == 1) 380a14842fSEric Dumazet *ptr = bytes; 390a14842fSEric Dumazet else if (len == 2) 400a14842fSEric Dumazet *(u16 *)ptr = bytes; 410a14842fSEric Dumazet else { 420a14842fSEric Dumazet *(u32 *)ptr = bytes; 430a14842fSEric Dumazet barrier(); 440a14842fSEric Dumazet } 450a14842fSEric Dumazet return ptr + len; 460a14842fSEric Dumazet } 470a14842fSEric Dumazet 480a14842fSEric Dumazet #define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0) 490a14842fSEric Dumazet 500a14842fSEric Dumazet #define EMIT1(b1) EMIT(b1, 1) 510a14842fSEric Dumazet #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2) 520a14842fSEric Dumazet #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3) 530a14842fSEric Dumazet #define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4) 540a14842fSEric Dumazet #define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0) 550a14842fSEric Dumazet 560a14842fSEric Dumazet #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */ 570a14842fSEric Dumazet #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */ 580a14842fSEric Dumazet 590a14842fSEric Dumazet static inline bool is_imm8(int value) 600a14842fSEric Dumazet { 610a14842fSEric Dumazet return value <= 127 && value >= -128; 620a14842fSEric Dumazet } 630a14842fSEric Dumazet 640a14842fSEric Dumazet static inline bool is_near(int offset) 650a14842fSEric Dumazet { 660a14842fSEric Dumazet return offset <= 127 && offset >= -128; 670a14842fSEric Dumazet } 680a14842fSEric Dumazet 690a14842fSEric Dumazet #define EMIT_JMP(offset) \ 700a14842fSEric Dumazet do { \ 710a14842fSEric Dumazet if (offset) { \ 720a14842fSEric Dumazet if (is_near(offset)) \ 730a14842fSEric Dumazet EMIT2(0xeb, offset); /* jmp .+off8 */ \ 740a14842fSEric Dumazet else \ 750a14842fSEric Dumazet EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \ 760a14842fSEric Dumazet } \ 770a14842fSEric Dumazet } while (0) 780a14842fSEric Dumazet 790a14842fSEric Dumazet /* list of x86 cond jumps opcodes (. + s8) 800a14842fSEric Dumazet * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32) 810a14842fSEric Dumazet */ 820a14842fSEric Dumazet #define X86_JB 0x72 830a14842fSEric Dumazet #define X86_JAE 0x73 840a14842fSEric Dumazet #define X86_JE 0x74 850a14842fSEric Dumazet #define X86_JNE 0x75 860a14842fSEric Dumazet #define X86_JBE 0x76 870a14842fSEric Dumazet #define X86_JA 0x77 880a14842fSEric Dumazet 890a14842fSEric Dumazet #define EMIT_COND_JMP(op, offset) \ 900a14842fSEric Dumazet do { \ 910a14842fSEric Dumazet if (is_near(offset)) \ 920a14842fSEric Dumazet EMIT2(op, offset); /* jxx .+off8 */ \ 930a14842fSEric Dumazet else { \ 940a14842fSEric Dumazet EMIT2(0x0f, op + 0x10); \ 950a14842fSEric Dumazet EMIT(offset, 4); /* jxx .+off32 */ \ 960a14842fSEric Dumazet } \ 970a14842fSEric Dumazet } while (0) 980a14842fSEric Dumazet 990a14842fSEric Dumazet #define COND_SEL(CODE, TOP, FOP) \ 1000a14842fSEric Dumazet case CODE: \ 1010a14842fSEric Dumazet t_op = TOP; \ 1020a14842fSEric Dumazet f_op = FOP; \ 1030a14842fSEric Dumazet goto cond_branch 1040a14842fSEric Dumazet 1050a14842fSEric Dumazet 1060a14842fSEric Dumazet #define SEEN_DATAREF 1 /* might call external helpers */ 1070a14842fSEric Dumazet #define SEEN_XREG 2 /* ebx is used */ 1080a14842fSEric Dumazet #define SEEN_MEM 4 /* use mem[] for temporary storage */ 1090a14842fSEric Dumazet 1100a14842fSEric Dumazet static inline void bpf_flush_icache(void *start, void *end) 1110a14842fSEric Dumazet { 1120a14842fSEric Dumazet mm_segment_t old_fs = get_fs(); 1130a14842fSEric Dumazet 1140a14842fSEric Dumazet set_fs(KERNEL_DS); 1150a14842fSEric Dumazet smp_wmb(); 1160a14842fSEric Dumazet flush_icache_range((unsigned long)start, (unsigned long)end); 1170a14842fSEric Dumazet set_fs(old_fs); 1180a14842fSEric Dumazet } 1190a14842fSEric Dumazet 1200a14842fSEric Dumazet 1210a14842fSEric Dumazet void bpf_jit_compile(struct sk_filter *fp) 1220a14842fSEric Dumazet { 1230a14842fSEric Dumazet u8 temp[64]; 1240a14842fSEric Dumazet u8 *prog; 1250a14842fSEric Dumazet unsigned int proglen, oldproglen = 0; 1260a14842fSEric Dumazet int ilen, i; 1270a14842fSEric Dumazet int t_offset, f_offset; 1280a14842fSEric Dumazet u8 t_op, f_op, seen = 0, pass; 1290a14842fSEric Dumazet u8 *image = NULL; 1300a14842fSEric Dumazet u8 *func; 1310a14842fSEric Dumazet int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */ 1320a14842fSEric Dumazet unsigned int cleanup_addr; /* epilogue code offset */ 1330a14842fSEric Dumazet unsigned int *addrs; 1340a14842fSEric Dumazet const struct sock_filter *filter = fp->insns; 1350a14842fSEric Dumazet int flen = fp->len; 1360a14842fSEric Dumazet 1370a14842fSEric Dumazet if (!bpf_jit_enable) 1380a14842fSEric Dumazet return; 1390a14842fSEric Dumazet 1400a14842fSEric Dumazet addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL); 1410a14842fSEric Dumazet if (addrs == NULL) 1420a14842fSEric Dumazet return; 1430a14842fSEric Dumazet 1440a14842fSEric Dumazet /* Before first pass, make a rough estimation of addrs[] 1450a14842fSEric Dumazet * each bpf instruction is translated to less than 64 bytes 1460a14842fSEric Dumazet */ 1470a14842fSEric Dumazet for (proglen = 0, i = 0; i < flen; i++) { 1480a14842fSEric Dumazet proglen += 64; 1490a14842fSEric Dumazet addrs[i] = proglen; 1500a14842fSEric Dumazet } 1510a14842fSEric Dumazet cleanup_addr = proglen; /* epilogue address */ 1520a14842fSEric Dumazet 1530a14842fSEric Dumazet for (pass = 0; pass < 10; pass++) { 154d00a9dd2SEric Dumazet u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen; 1550a14842fSEric Dumazet /* no prologue/epilogue for trivial filters (RET something) */ 1560a14842fSEric Dumazet proglen = 0; 1570a14842fSEric Dumazet prog = temp; 1580a14842fSEric Dumazet 159d00a9dd2SEric Dumazet if (seen_or_pass0) { 1600a14842fSEric Dumazet EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */ 1610a14842fSEric Dumazet EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */ 1620a14842fSEric Dumazet /* note : must save %rbx in case bpf_error is hit */ 163d00a9dd2SEric Dumazet if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF)) 1640a14842fSEric Dumazet EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */ 165d00a9dd2SEric Dumazet if (seen_or_pass0 & SEEN_XREG) 1660a14842fSEric Dumazet CLEAR_X(); /* make sure we dont leek kernel memory */ 1670a14842fSEric Dumazet 1680a14842fSEric Dumazet /* 1690a14842fSEric Dumazet * If this filter needs to access skb data, 1700a14842fSEric Dumazet * loads r9 and r8 with : 1710a14842fSEric Dumazet * r9 = skb->len - skb->data_len 1720a14842fSEric Dumazet * r8 = skb->data 1730a14842fSEric Dumazet */ 174d00a9dd2SEric Dumazet if (seen_or_pass0 & SEEN_DATAREF) { 1750a14842fSEric Dumazet if (offsetof(struct sk_buff, len) <= 127) 1760a14842fSEric Dumazet /* mov off8(%rdi),%r9d */ 1770a14842fSEric Dumazet EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len)); 1780a14842fSEric Dumazet else { 1790a14842fSEric Dumazet /* mov off32(%rdi),%r9d */ 1800a14842fSEric Dumazet EMIT3(0x44, 0x8b, 0x8f); 1810a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, len), 4); 1820a14842fSEric Dumazet } 1830a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, data_len))) 1840a14842fSEric Dumazet /* sub off8(%rdi),%r9d */ 1850a14842fSEric Dumazet EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len)); 1860a14842fSEric Dumazet else { 1870a14842fSEric Dumazet EMIT3(0x44, 0x2b, 0x8f); 1880a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, data_len), 4); 1890a14842fSEric Dumazet } 1900a14842fSEric Dumazet 1910a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, data))) 1920a14842fSEric Dumazet /* mov off8(%rdi),%r8 */ 1930a14842fSEric Dumazet EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data)); 1940a14842fSEric Dumazet else { 1950a14842fSEric Dumazet /* mov off32(%rdi),%r8 */ 1960a14842fSEric Dumazet EMIT3(0x4c, 0x8b, 0x87); 1970a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, data), 4); 1980a14842fSEric Dumazet } 1990a14842fSEric Dumazet } 2000a14842fSEric Dumazet } 2010a14842fSEric Dumazet 2020a14842fSEric Dumazet switch (filter[0].code) { 2030a14842fSEric Dumazet case BPF_S_RET_K: 2040a14842fSEric Dumazet case BPF_S_LD_W_LEN: 2050a14842fSEric Dumazet case BPF_S_ANC_PROTOCOL: 2060a14842fSEric Dumazet case BPF_S_ANC_IFINDEX: 2070a14842fSEric Dumazet case BPF_S_ANC_MARK: 2080a14842fSEric Dumazet case BPF_S_ANC_RXHASH: 2090a14842fSEric Dumazet case BPF_S_ANC_CPU: 2100a14842fSEric Dumazet case BPF_S_ANC_QUEUE: 2110a14842fSEric Dumazet case BPF_S_LD_W_ABS: 2120a14842fSEric Dumazet case BPF_S_LD_H_ABS: 2130a14842fSEric Dumazet case BPF_S_LD_B_ABS: 2140a14842fSEric Dumazet /* first instruction sets A register (or is RET 'constant') */ 2150a14842fSEric Dumazet break; 2160a14842fSEric Dumazet default: 2170a14842fSEric Dumazet /* make sure we dont leak kernel information to user */ 2180a14842fSEric Dumazet CLEAR_A(); /* A = 0 */ 2190a14842fSEric Dumazet } 2200a14842fSEric Dumazet 2210a14842fSEric Dumazet for (i = 0; i < flen; i++) { 2220a14842fSEric Dumazet unsigned int K = filter[i].k; 2230a14842fSEric Dumazet 2240a14842fSEric Dumazet switch (filter[i].code) { 2250a14842fSEric Dumazet case BPF_S_ALU_ADD_X: /* A += X; */ 2260a14842fSEric Dumazet seen |= SEEN_XREG; 2270a14842fSEric Dumazet EMIT2(0x01, 0xd8); /* add %ebx,%eax */ 2280a14842fSEric Dumazet break; 2290a14842fSEric Dumazet case BPF_S_ALU_ADD_K: /* A += K; */ 2300a14842fSEric Dumazet if (!K) 2310a14842fSEric Dumazet break; 2320a14842fSEric Dumazet if (is_imm8(K)) 2330a14842fSEric Dumazet EMIT3(0x83, 0xc0, K); /* add imm8,%eax */ 2340a14842fSEric Dumazet else 2350a14842fSEric Dumazet EMIT1_off32(0x05, K); /* add imm32,%eax */ 2360a14842fSEric Dumazet break; 2370a14842fSEric Dumazet case BPF_S_ALU_SUB_X: /* A -= X; */ 2380a14842fSEric Dumazet seen |= SEEN_XREG; 2390a14842fSEric Dumazet EMIT2(0x29, 0xd8); /* sub %ebx,%eax */ 2400a14842fSEric Dumazet break; 2410a14842fSEric Dumazet case BPF_S_ALU_SUB_K: /* A -= K */ 2420a14842fSEric Dumazet if (!K) 2430a14842fSEric Dumazet break; 2440a14842fSEric Dumazet if (is_imm8(K)) 2450a14842fSEric Dumazet EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */ 2460a14842fSEric Dumazet else 2470a14842fSEric Dumazet EMIT1_off32(0x2d, K); /* sub imm32,%eax */ 2480a14842fSEric Dumazet break; 2490a14842fSEric Dumazet case BPF_S_ALU_MUL_X: /* A *= X; */ 2500a14842fSEric Dumazet seen |= SEEN_XREG; 2510a14842fSEric Dumazet EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */ 2520a14842fSEric Dumazet break; 2530a14842fSEric Dumazet case BPF_S_ALU_MUL_K: /* A *= K */ 2540a14842fSEric Dumazet if (is_imm8(K)) 2550a14842fSEric Dumazet EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */ 2560a14842fSEric Dumazet else { 2570a14842fSEric Dumazet EMIT2(0x69, 0xc0); /* imul imm32,%eax */ 2580a14842fSEric Dumazet EMIT(K, 4); 2590a14842fSEric Dumazet } 2600a14842fSEric Dumazet break; 2610a14842fSEric Dumazet case BPF_S_ALU_DIV_X: /* A /= X; */ 2620a14842fSEric Dumazet seen |= SEEN_XREG; 2630a14842fSEric Dumazet EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ 264d00a9dd2SEric Dumazet if (pc_ret0 > 0) { 265d00a9dd2SEric Dumazet /* addrs[pc_ret0 - 1] is start address of target 266d00a9dd2SEric Dumazet * (addrs[i] - 4) is the address following this jmp 267d00a9dd2SEric Dumazet * ("xor %edx,%edx; div %ebx" being 4 bytes long) 268d00a9dd2SEric Dumazet */ 269d00a9dd2SEric Dumazet EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] - 270d00a9dd2SEric Dumazet (addrs[i] - 4)); 271d00a9dd2SEric Dumazet } else { 2720a14842fSEric Dumazet EMIT_COND_JMP(X86_JNE, 2 + 5); 2730a14842fSEric Dumazet CLEAR_A(); 2740a14842fSEric Dumazet EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */ 2750a14842fSEric Dumazet } 2760a14842fSEric Dumazet EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */ 2770a14842fSEric Dumazet break; 2780a14842fSEric Dumazet case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */ 2790a14842fSEric Dumazet EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */ 2800a14842fSEric Dumazet EMIT(K, 4); 2810a14842fSEric Dumazet EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */ 2820a14842fSEric Dumazet break; 2830a14842fSEric Dumazet case BPF_S_ALU_AND_X: 2840a14842fSEric Dumazet seen |= SEEN_XREG; 2850a14842fSEric Dumazet EMIT2(0x21, 0xd8); /* and %ebx,%eax */ 2860a14842fSEric Dumazet break; 2870a14842fSEric Dumazet case BPF_S_ALU_AND_K: 2880a14842fSEric Dumazet if (K >= 0xFFFFFF00) { 2890a14842fSEric Dumazet EMIT2(0x24, K & 0xFF); /* and imm8,%al */ 2900a14842fSEric Dumazet } else if (K >= 0xFFFF0000) { 2910a14842fSEric Dumazet EMIT2(0x66, 0x25); /* and imm16,%ax */ 2920a14842fSEric Dumazet EMIT2(K, 2); 2930a14842fSEric Dumazet } else { 2940a14842fSEric Dumazet EMIT1_off32(0x25, K); /* and imm32,%eax */ 2950a14842fSEric Dumazet } 2960a14842fSEric Dumazet break; 2970a14842fSEric Dumazet case BPF_S_ALU_OR_X: 2980a14842fSEric Dumazet seen |= SEEN_XREG; 2990a14842fSEric Dumazet EMIT2(0x09, 0xd8); /* or %ebx,%eax */ 3000a14842fSEric Dumazet break; 3010a14842fSEric Dumazet case BPF_S_ALU_OR_K: 3020a14842fSEric Dumazet if (is_imm8(K)) 3030a14842fSEric Dumazet EMIT3(0x83, 0xc8, K); /* or imm8,%eax */ 3040a14842fSEric Dumazet else 3050a14842fSEric Dumazet EMIT1_off32(0x0d, K); /* or imm32,%eax */ 3060a14842fSEric Dumazet break; 3070a14842fSEric Dumazet case BPF_S_ALU_LSH_X: /* A <<= X; */ 3080a14842fSEric Dumazet seen |= SEEN_XREG; 3090a14842fSEric Dumazet EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */ 3100a14842fSEric Dumazet break; 3110a14842fSEric Dumazet case BPF_S_ALU_LSH_K: 3120a14842fSEric Dumazet if (K == 0) 3130a14842fSEric Dumazet break; 3140a14842fSEric Dumazet else if (K == 1) 3150a14842fSEric Dumazet EMIT2(0xd1, 0xe0); /* shl %eax */ 3160a14842fSEric Dumazet else 3170a14842fSEric Dumazet EMIT3(0xc1, 0xe0, K); 3180a14842fSEric Dumazet break; 3190a14842fSEric Dumazet case BPF_S_ALU_RSH_X: /* A >>= X; */ 3200a14842fSEric Dumazet seen |= SEEN_XREG; 3210a14842fSEric Dumazet EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */ 3220a14842fSEric Dumazet break; 3230a14842fSEric Dumazet case BPF_S_ALU_RSH_K: /* A >>= K; */ 3240a14842fSEric Dumazet if (K == 0) 3250a14842fSEric Dumazet break; 3260a14842fSEric Dumazet else if (K == 1) 3270a14842fSEric Dumazet EMIT2(0xd1, 0xe8); /* shr %eax */ 3280a14842fSEric Dumazet else 3290a14842fSEric Dumazet EMIT3(0xc1, 0xe8, K); 3300a14842fSEric Dumazet break; 3310a14842fSEric Dumazet case BPF_S_ALU_NEG: 3320a14842fSEric Dumazet EMIT2(0xf7, 0xd8); /* neg %eax */ 3330a14842fSEric Dumazet break; 3340a14842fSEric Dumazet case BPF_S_RET_K: 3350a14842fSEric Dumazet if (!K) { 3360a14842fSEric Dumazet if (pc_ret0 == -1) 3370a14842fSEric Dumazet pc_ret0 = i; 3380a14842fSEric Dumazet CLEAR_A(); 3390a14842fSEric Dumazet } else { 3400a14842fSEric Dumazet EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ 3410a14842fSEric Dumazet } 3420a14842fSEric Dumazet /* fallinto */ 3430a14842fSEric Dumazet case BPF_S_RET_A: 344d00a9dd2SEric Dumazet if (seen_or_pass0) { 3450a14842fSEric Dumazet if (i != flen - 1) { 3460a14842fSEric Dumazet EMIT_JMP(cleanup_addr - addrs[i]); 3470a14842fSEric Dumazet break; 3480a14842fSEric Dumazet } 349d00a9dd2SEric Dumazet if (seen_or_pass0 & SEEN_XREG) 3500a14842fSEric Dumazet EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */ 3510a14842fSEric Dumazet EMIT1(0xc9); /* leaveq */ 3520a14842fSEric Dumazet } 3530a14842fSEric Dumazet EMIT1(0xc3); /* ret */ 3540a14842fSEric Dumazet break; 3550a14842fSEric Dumazet case BPF_S_MISC_TAX: /* X = A */ 3560a14842fSEric Dumazet seen |= SEEN_XREG; 3570a14842fSEric Dumazet EMIT2(0x89, 0xc3); /* mov %eax,%ebx */ 3580a14842fSEric Dumazet break; 3590a14842fSEric Dumazet case BPF_S_MISC_TXA: /* A = X */ 3600a14842fSEric Dumazet seen |= SEEN_XREG; 3610a14842fSEric Dumazet EMIT2(0x89, 0xd8); /* mov %ebx,%eax */ 3620a14842fSEric Dumazet break; 3630a14842fSEric Dumazet case BPF_S_LD_IMM: /* A = K */ 3640a14842fSEric Dumazet if (!K) 3650a14842fSEric Dumazet CLEAR_A(); 3660a14842fSEric Dumazet else 3670a14842fSEric Dumazet EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ 3680a14842fSEric Dumazet break; 3690a14842fSEric Dumazet case BPF_S_LDX_IMM: /* X = K */ 3700a14842fSEric Dumazet seen |= SEEN_XREG; 3710a14842fSEric Dumazet if (!K) 3720a14842fSEric Dumazet CLEAR_X(); 3730a14842fSEric Dumazet else 3740a14842fSEric Dumazet EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */ 3750a14842fSEric Dumazet break; 3760a14842fSEric Dumazet case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */ 3770a14842fSEric Dumazet seen |= SEEN_MEM; 3780a14842fSEric Dumazet EMIT3(0x8b, 0x45, 0xf0 - K*4); 3790a14842fSEric Dumazet break; 3800a14842fSEric Dumazet case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */ 3810a14842fSEric Dumazet seen |= SEEN_XREG | SEEN_MEM; 3820a14842fSEric Dumazet EMIT3(0x8b, 0x5d, 0xf0 - K*4); 3830a14842fSEric Dumazet break; 3840a14842fSEric Dumazet case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */ 3850a14842fSEric Dumazet seen |= SEEN_MEM; 3860a14842fSEric Dumazet EMIT3(0x89, 0x45, 0xf0 - K*4); 3870a14842fSEric Dumazet break; 3880a14842fSEric Dumazet case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */ 3890a14842fSEric Dumazet seen |= SEEN_XREG | SEEN_MEM; 3900a14842fSEric Dumazet EMIT3(0x89, 0x5d, 0xf0 - K*4); 3910a14842fSEric Dumazet break; 3920a14842fSEric Dumazet case BPF_S_LD_W_LEN: /* A = skb->len; */ 3930a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); 3940a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, len))) 3950a14842fSEric Dumazet /* mov off8(%rdi),%eax */ 3960a14842fSEric Dumazet EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len)); 3970a14842fSEric Dumazet else { 3980a14842fSEric Dumazet EMIT2(0x8b, 0x87); 3990a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, len), 4); 4000a14842fSEric Dumazet } 4010a14842fSEric Dumazet break; 4020a14842fSEric Dumazet case BPF_S_LDX_W_LEN: /* X = skb->len; */ 4030a14842fSEric Dumazet seen |= SEEN_XREG; 4040a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, len))) 4050a14842fSEric Dumazet /* mov off8(%rdi),%ebx */ 4060a14842fSEric Dumazet EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len)); 4070a14842fSEric Dumazet else { 4080a14842fSEric Dumazet EMIT2(0x8b, 0x9f); 4090a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, len), 4); 4100a14842fSEric Dumazet } 4110a14842fSEric Dumazet break; 4120a14842fSEric Dumazet case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */ 4130a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); 4140a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, protocol))) { 4150a14842fSEric Dumazet /* movzwl off8(%rdi),%eax */ 4160a14842fSEric Dumazet EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol)); 4170a14842fSEric Dumazet } else { 4180a14842fSEric Dumazet EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ 4190a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, protocol), 4); 4200a14842fSEric Dumazet } 4210a14842fSEric Dumazet EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */ 4220a14842fSEric Dumazet break; 4230a14842fSEric Dumazet case BPF_S_ANC_IFINDEX: 4240a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, dev))) { 4250a14842fSEric Dumazet /* movq off8(%rdi),%rax */ 4260a14842fSEric Dumazet EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev)); 4270a14842fSEric Dumazet } else { 4280a14842fSEric Dumazet EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */ 4290a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, dev), 4); 4300a14842fSEric Dumazet } 4310a14842fSEric Dumazet EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */ 4320a14842fSEric Dumazet EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6)); 4330a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); 4340a14842fSEric Dumazet EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */ 4350a14842fSEric Dumazet EMIT(offsetof(struct net_device, ifindex), 4); 4360a14842fSEric Dumazet break; 4370a14842fSEric Dumazet case BPF_S_ANC_MARK: 4380a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); 4390a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, mark))) { 4400a14842fSEric Dumazet /* mov off8(%rdi),%eax */ 4410a14842fSEric Dumazet EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark)); 4420a14842fSEric Dumazet } else { 4430a14842fSEric Dumazet EMIT2(0x8b, 0x87); 4440a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, mark), 4); 4450a14842fSEric Dumazet } 4460a14842fSEric Dumazet break; 4470a14842fSEric Dumazet case BPF_S_ANC_RXHASH: 4480a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4); 4490a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, rxhash))) { 4500a14842fSEric Dumazet /* mov off8(%rdi),%eax */ 4510a14842fSEric Dumazet EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash)); 4520a14842fSEric Dumazet } else { 4530a14842fSEric Dumazet EMIT2(0x8b, 0x87); 4540a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, rxhash), 4); 4550a14842fSEric Dumazet } 4560a14842fSEric Dumazet break; 4570a14842fSEric Dumazet case BPF_S_ANC_QUEUE: 4580a14842fSEric Dumazet BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); 4590a14842fSEric Dumazet if (is_imm8(offsetof(struct sk_buff, queue_mapping))) { 4600a14842fSEric Dumazet /* movzwl off8(%rdi),%eax */ 4610a14842fSEric Dumazet EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping)); 4620a14842fSEric Dumazet } else { 4630a14842fSEric Dumazet EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ 4640a14842fSEric Dumazet EMIT(offsetof(struct sk_buff, queue_mapping), 4); 4650a14842fSEric Dumazet } 4660a14842fSEric Dumazet break; 4670a14842fSEric Dumazet case BPF_S_ANC_CPU: 4680a14842fSEric Dumazet #ifdef CONFIG_SMP 4690a14842fSEric Dumazet EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */ 4700a14842fSEric Dumazet EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */ 4710a14842fSEric Dumazet #else 4720a14842fSEric Dumazet CLEAR_A(); 4730a14842fSEric Dumazet #endif 4740a14842fSEric Dumazet break; 4750a14842fSEric Dumazet case BPF_S_LD_W_ABS: 4760a14842fSEric Dumazet func = sk_load_word; 4770a14842fSEric Dumazet common_load: seen |= SEEN_DATAREF; 4780a14842fSEric Dumazet if ((int)K < 0) 4790a14842fSEric Dumazet goto out; 4800a14842fSEric Dumazet t_offset = func - (image + addrs[i]); 4810a14842fSEric Dumazet EMIT1_off32(0xbe, K); /* mov imm32,%esi */ 4820a14842fSEric Dumazet EMIT1_off32(0xe8, t_offset); /* call */ 4830a14842fSEric Dumazet break; 4840a14842fSEric Dumazet case BPF_S_LD_H_ABS: 4850a14842fSEric Dumazet func = sk_load_half; 4860a14842fSEric Dumazet goto common_load; 4870a14842fSEric Dumazet case BPF_S_LD_B_ABS: 4880a14842fSEric Dumazet func = sk_load_byte; 4890a14842fSEric Dumazet goto common_load; 4900a14842fSEric Dumazet case BPF_S_LDX_B_MSH: 4910a14842fSEric Dumazet if ((int)K < 0) { 492d00a9dd2SEric Dumazet if (pc_ret0 > 0) { 493d00a9dd2SEric Dumazet /* addrs[pc_ret0 - 1] is the start address */ 494d00a9dd2SEric Dumazet EMIT_JMP(addrs[pc_ret0 - 1] - addrs[i]); 4950a14842fSEric Dumazet break; 4960a14842fSEric Dumazet } 4970a14842fSEric Dumazet CLEAR_A(); 4980a14842fSEric Dumazet EMIT_JMP(cleanup_addr - addrs[i]); 4990a14842fSEric Dumazet break; 5000a14842fSEric Dumazet } 5010a14842fSEric Dumazet seen |= SEEN_DATAREF | SEEN_XREG; 5020a14842fSEric Dumazet t_offset = sk_load_byte_msh - (image + addrs[i]); 5030a14842fSEric Dumazet EMIT1_off32(0xbe, K); /* mov imm32,%esi */ 5040a14842fSEric Dumazet EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */ 5050a14842fSEric Dumazet break; 5060a14842fSEric Dumazet case BPF_S_LD_W_IND: 5070a14842fSEric Dumazet func = sk_load_word_ind; 5080a14842fSEric Dumazet common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG; 5090a14842fSEric Dumazet t_offset = func - (image + addrs[i]); 5100a14842fSEric Dumazet EMIT1_off32(0xbe, K); /* mov imm32,%esi */ 5110a14842fSEric Dumazet EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */ 5120a14842fSEric Dumazet break; 5130a14842fSEric Dumazet case BPF_S_LD_H_IND: 5140a14842fSEric Dumazet func = sk_load_half_ind; 5150a14842fSEric Dumazet goto common_load_ind; 5160a14842fSEric Dumazet case BPF_S_LD_B_IND: 5170a14842fSEric Dumazet func = sk_load_byte_ind; 5180a14842fSEric Dumazet goto common_load_ind; 5190a14842fSEric Dumazet case BPF_S_JMP_JA: 5200a14842fSEric Dumazet t_offset = addrs[i + K] - addrs[i]; 5210a14842fSEric Dumazet EMIT_JMP(t_offset); 5220a14842fSEric Dumazet break; 5230a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE); 5240a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB); 5250a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE); 5260a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE); 5270a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE); 5280a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB); 5290a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE); 5300a14842fSEric Dumazet COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE); 5310a14842fSEric Dumazet 5320a14842fSEric Dumazet cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i]; 5330a14842fSEric Dumazet t_offset = addrs[i + filter[i].jt] - addrs[i]; 5340a14842fSEric Dumazet 5350a14842fSEric Dumazet /* same targets, can avoid doing the test :) */ 5360a14842fSEric Dumazet if (filter[i].jt == filter[i].jf) { 5370a14842fSEric Dumazet EMIT_JMP(t_offset); 5380a14842fSEric Dumazet break; 5390a14842fSEric Dumazet } 5400a14842fSEric Dumazet 5410a14842fSEric Dumazet switch (filter[i].code) { 5420a14842fSEric Dumazet case BPF_S_JMP_JGT_X: 5430a14842fSEric Dumazet case BPF_S_JMP_JGE_X: 5440a14842fSEric Dumazet case BPF_S_JMP_JEQ_X: 5450a14842fSEric Dumazet seen |= SEEN_XREG; 5460a14842fSEric Dumazet EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */ 5470a14842fSEric Dumazet break; 5480a14842fSEric Dumazet case BPF_S_JMP_JSET_X: 5490a14842fSEric Dumazet seen |= SEEN_XREG; 5500a14842fSEric Dumazet EMIT2(0x85, 0xd8); /* test %ebx,%eax */ 5510a14842fSEric Dumazet break; 5520a14842fSEric Dumazet case BPF_S_JMP_JEQ_K: 5530a14842fSEric Dumazet if (K == 0) { 5540a14842fSEric Dumazet EMIT2(0x85, 0xc0); /* test %eax,%eax */ 5550a14842fSEric Dumazet break; 5560a14842fSEric Dumazet } 5570a14842fSEric Dumazet case BPF_S_JMP_JGT_K: 5580a14842fSEric Dumazet case BPF_S_JMP_JGE_K: 5590a14842fSEric Dumazet if (K <= 127) 5600a14842fSEric Dumazet EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */ 5610a14842fSEric Dumazet else 5620a14842fSEric Dumazet EMIT1_off32(0x3d, K); /* cmp imm32,%eax */ 5630a14842fSEric Dumazet break; 5640a14842fSEric Dumazet case BPF_S_JMP_JSET_K: 5650a14842fSEric Dumazet if (K <= 0xFF) 5660a14842fSEric Dumazet EMIT2(0xa8, K); /* test imm8,%al */ 5670a14842fSEric Dumazet else if (!(K & 0xFFFF00FF)) 5680a14842fSEric Dumazet EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */ 5690a14842fSEric Dumazet else if (K <= 0xFFFF) { 5700a14842fSEric Dumazet EMIT2(0x66, 0xa9); /* test imm16,%ax */ 5710a14842fSEric Dumazet EMIT(K, 2); 5720a14842fSEric Dumazet } else { 5730a14842fSEric Dumazet EMIT1_off32(0xa9, K); /* test imm32,%eax */ 5740a14842fSEric Dumazet } 5750a14842fSEric Dumazet break; 5760a14842fSEric Dumazet } 5770a14842fSEric Dumazet if (filter[i].jt != 0) { 578a03ffcf8SMarkus Kötter if (filter[i].jf && f_offset) 579a03ffcf8SMarkus Kötter t_offset += is_near(f_offset) ? 2 : 5; 5800a14842fSEric Dumazet EMIT_COND_JMP(t_op, t_offset); 5810a14842fSEric Dumazet if (filter[i].jf) 5820a14842fSEric Dumazet EMIT_JMP(f_offset); 5830a14842fSEric Dumazet break; 5840a14842fSEric Dumazet } 5850a14842fSEric Dumazet EMIT_COND_JMP(f_op, f_offset); 5860a14842fSEric Dumazet break; 5870a14842fSEric Dumazet default: 5880a14842fSEric Dumazet /* hmm, too complex filter, give up with jit compiler */ 5890a14842fSEric Dumazet goto out; 5900a14842fSEric Dumazet } 5910a14842fSEric Dumazet ilen = prog - temp; 5920a14842fSEric Dumazet if (image) { 5930a14842fSEric Dumazet if (unlikely(proglen + ilen > oldproglen)) { 5940a14842fSEric Dumazet pr_err("bpb_jit_compile fatal error\n"); 5950a14842fSEric Dumazet kfree(addrs); 5960a14842fSEric Dumazet module_free(NULL, image); 5970a14842fSEric Dumazet return; 5980a14842fSEric Dumazet } 5990a14842fSEric Dumazet memcpy(image + proglen, temp, ilen); 6000a14842fSEric Dumazet } 6010a14842fSEric Dumazet proglen += ilen; 6020a14842fSEric Dumazet addrs[i] = proglen; 6030a14842fSEric Dumazet prog = temp; 6040a14842fSEric Dumazet } 6050a14842fSEric Dumazet /* last bpf instruction is always a RET : 6060a14842fSEric Dumazet * use it to give the cleanup instruction(s) addr 6070a14842fSEric Dumazet */ 6080a14842fSEric Dumazet cleanup_addr = proglen - 1; /* ret */ 609d00a9dd2SEric Dumazet if (seen_or_pass0) 6100a14842fSEric Dumazet cleanup_addr -= 1; /* leaveq */ 611d00a9dd2SEric Dumazet if (seen_or_pass0 & SEEN_XREG) 6120a14842fSEric Dumazet cleanup_addr -= 4; /* mov -8(%rbp),%rbx */ 6130a14842fSEric Dumazet 6140a14842fSEric Dumazet if (image) { 615d00a9dd2SEric Dumazet if (proglen != oldproglen) 616d00a9dd2SEric Dumazet pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen); 6170a14842fSEric Dumazet break; 6180a14842fSEric Dumazet } 6190a14842fSEric Dumazet if (proglen == oldproglen) { 6200a14842fSEric Dumazet image = module_alloc(max_t(unsigned int, 6210a14842fSEric Dumazet proglen, 6220a14842fSEric Dumazet sizeof(struct work_struct))); 6230a14842fSEric Dumazet if (!image) 6240a14842fSEric Dumazet goto out; 6250a14842fSEric Dumazet } 6260a14842fSEric Dumazet oldproglen = proglen; 6270a14842fSEric Dumazet } 6280a14842fSEric Dumazet if (bpf_jit_enable > 1) 6290a14842fSEric Dumazet pr_err("flen=%d proglen=%u pass=%d image=%p\n", 6300a14842fSEric Dumazet flen, proglen, pass, image); 6310a14842fSEric Dumazet 6320a14842fSEric Dumazet if (image) { 6330a14842fSEric Dumazet if (bpf_jit_enable > 1) 6340a14842fSEric Dumazet print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS, 6350a14842fSEric Dumazet 16, 1, image, proglen, false); 6360a14842fSEric Dumazet 6370a14842fSEric Dumazet bpf_flush_icache(image, image + proglen); 6380a14842fSEric Dumazet 6390a14842fSEric Dumazet fp->bpf_func = (void *)image; 6400a14842fSEric Dumazet } 6410a14842fSEric Dumazet out: 6420a14842fSEric Dumazet kfree(addrs); 6430a14842fSEric Dumazet return; 6440a14842fSEric Dumazet } 6450a14842fSEric Dumazet 6460a14842fSEric Dumazet static void jit_free_defer(struct work_struct *arg) 6470a14842fSEric Dumazet { 6480a14842fSEric Dumazet module_free(NULL, arg); 6490a14842fSEric Dumazet } 6500a14842fSEric Dumazet 6510a14842fSEric Dumazet /* run from softirq, we must use a work_struct to call 6520a14842fSEric Dumazet * module_free() from process context 6530a14842fSEric Dumazet */ 6540a14842fSEric Dumazet void bpf_jit_free(struct sk_filter *fp) 6550a14842fSEric Dumazet { 6560a14842fSEric Dumazet if (fp->bpf_func != sk_run_filter) { 6570a14842fSEric Dumazet struct work_struct *work = (struct work_struct *)fp->bpf_func; 6580a14842fSEric Dumazet 6590a14842fSEric Dumazet INIT_WORK(work, jit_free_defer); 6600a14842fSEric Dumazet schedule_work(work); 6610a14842fSEric Dumazet } 6620a14842fSEric Dumazet } 663