/* * BPF Jit compiler for s390. * * Copyright IBM Corp. 2012 * * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> */ #include <linux/moduleloader.h> #include <linux/netdevice.h> #include <linux/if_vlan.h> #include <linux/filter.h> #include <asm/cacheflush.h> #include <asm/processor.h> #include <asm/facility.h> /* * Conventions: * %r2 = skb pointer * %r3 = offset parameter * %r4 = scratch register / length parameter * %r5 = BPF A accumulator * %r8 = return address * %r9 = save register for skb pointer * %r10 = skb->data * %r11 = skb->len - skb->data_len (headlen) * %r12 = BPF X accumulator * %r13 = literal pool pointer * 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS */ int bpf_jit_enable __read_mostly; /* * assembly code in arch/x86/net/bpf_jit.S */ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[]; extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[]; struct bpf_jit { unsigned int seen; u8 *start; u8 *prg; u8 *mid; u8 *lit; u8 *end; u8 *base_ip; u8 *ret0_ip; u8 *exit_ip; unsigned int off_load_word; unsigned int off_load_half; unsigned int off_load_byte; unsigned int off_load_bmsh; unsigned int off_load_iword; unsigned int off_load_ihalf; unsigned int off_load_ibyte; }; #define BPF_SIZE_MAX 4096 /* Max size for program */ #define SEEN_DATAREF 1 /* might call external helpers */ #define SEEN_XREG 2 /* ebx is used */ #define SEEN_MEM 4 /* use mem[] for temporary storage */ #define SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */ #define SEEN_LITERAL 16 /* code uses literals */ #define SEEN_LOAD_WORD 32 /* code uses sk_load_word */ #define SEEN_LOAD_HALF 64 /* code uses sk_load_half */ #define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */ #define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */ #define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */ #define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */ #define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */ #define EMIT2(op) \ ({ \ if (jit->prg + 2 <= jit->mid) \ *(u16 *) jit->prg = op; \ jit->prg += 2; \ }) #define EMIT4(op) \ ({ \ if (jit->prg + 4 <= jit->mid) \ *(u32 *) jit->prg = op; \ jit->prg += 4; \ }) #define EMIT4_DISP(op, disp) \ ({ \ unsigned int __disp = (disp) & 0xfff; \ EMIT4(op | __disp); \ }) #define EMIT4_IMM(op, imm) \ ({ \ unsigned int __imm = (imm) & 0xffff; \ EMIT4(op | __imm); \ }) #define EMIT4_PCREL(op, pcrel) \ ({ \ long __pcrel = ((pcrel) >> 1) & 0xffff; \ EMIT4(op | __pcrel); \ }) #define EMIT6(op1, op2) \ ({ \ if (jit->prg + 6 <= jit->mid) { \ *(u32 *) jit->prg = op1; \ *(u16 *) (jit->prg + 4) = op2; \ } \ jit->prg += 6; \ }) #define EMIT6_DISP(op1, op2, disp) \ ({ \ unsigned int __disp = (disp) & 0xfff; \ EMIT6(op1 | __disp, op2); \ }) #define EMIT6_IMM(op, imm) \ ({ \ unsigned int __imm = (imm); \ EMIT6(op | (__imm >> 16), __imm & 0xffff); \ }) #define EMIT_CONST(val) \ ({ \ unsigned int ret; \ ret = (unsigned int) (jit->lit - jit->base_ip); \ jit->seen |= SEEN_LITERAL; \ if (jit->lit + 4 <= jit->end) \ *(u32 *) jit->lit = val; \ jit->lit += 4; \ ret; \ }) #define EMIT_FN_CONST(bit, fn) \ ({ \ unsigned int ret; \ ret = (unsigned int) (jit->lit - jit->base_ip); \ if (jit->seen & bit) { \ jit->seen |= SEEN_LITERAL; \ if (jit->lit + 8 <= jit->end) \ *(void **) jit->lit = fn; \ jit->lit += 8; \ } \ ret; \ }) static void bpf_jit_prologue(struct bpf_jit *jit) { /* Save registers and create stack frame if necessary */ if (jit->seen & SEEN_DATAREF) { /* stmg %r8,%r15,88(%r15) */ EMIT6(0xeb8ff058, 0x0024); /* lgr %r14,%r15 */ EMIT4(0xb90400ef); /* ahi %r15,<offset> */ EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80); /* stg %r14,152(%r15) */ EMIT6(0xe3e0f098, 0x0024); } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL)) /* stmg %r12,%r13,120(%r15) */ EMIT6(0xebcdf078, 0x0024); else if (jit->seen & SEEN_XREG) /* stg %r12,120(%r15) */ EMIT6(0xe3c0f078, 0x0024); else if (jit->seen & SEEN_LITERAL) /* stg %r13,128(%r15) */ EMIT6(0xe3d0f080, 0x0024); /* Setup literal pool */ if (jit->seen & SEEN_LITERAL) { /* basr %r13,0 */ EMIT2(0x0dd0); jit->base_ip = jit->prg; } jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word); jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half); jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte); jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh); jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind); jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind); jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind); /* Filter needs to access skb data */ if (jit->seen & SEEN_DATAREF) { /* l %r11,<len>(%r2) */ EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len)); /* s %r11,<data_len>(%r2) */ EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len)); /* lg %r10,<data>(%r2) */ EMIT6_DISP(0xe3a02000, 0x0004, offsetof(struct sk_buff, data)); } } static void bpf_jit_epilogue(struct bpf_jit *jit) { /* Return 0 */ if (jit->seen & SEEN_RET0) { jit->ret0_ip = jit->prg; /* lghi %r2,0 */ EMIT4(0xa7290000); } jit->exit_ip = jit->prg; /* Restore registers */ if (jit->seen & SEEN_DATAREF) /* lmg %r8,%r15,<offset>(%r15) */ EMIT6_DISP(0xeb8ff000, 0x0004, (jit->seen & SEEN_MEM) ? 200 : 168); else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL)) /* lmg %r12,%r13,120(%r15) */ EMIT6(0xebcdf078, 0x0004); else if (jit->seen & SEEN_XREG) /* lg %r12,120(%r15) */ EMIT6(0xe3c0f078, 0x0004); else if (jit->seen & SEEN_LITERAL) /* lg %r13,128(%r15) */ EMIT6(0xe3d0f080, 0x0004); /* br %r14 */ EMIT2(0x07fe); } /* * make sure we dont leak kernel information to user */ static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter) { /* Clear temporary memory if (seen & SEEN_MEM) */ if (jit->seen & SEEN_MEM) /* xc 0(64,%r15),0(%r15) */ EMIT6(0xd73ff000, 0xf000); /* Clear X if (seen & SEEN_XREG) */ if (jit->seen & SEEN_XREG) /* lhi %r12,0 */ EMIT4(0xa7c80000); /* Clear A if the first register does not set it. */ switch (filter[0].code) { case BPF_S_LD_W_ABS: case BPF_S_LD_H_ABS: case BPF_S_LD_B_ABS: case BPF_S_LD_W_LEN: case BPF_S_LD_W_IND: case BPF_S_LD_H_IND: case BPF_S_LD_B_IND: case BPF_S_LDX_B_MSH: case BPF_S_LD_IMM: case BPF_S_LD_MEM: case BPF_S_MISC_TXA: case BPF_S_ANC_PROTOCOL: case BPF_S_ANC_PKTTYPE: case BPF_S_ANC_IFINDEX: case BPF_S_ANC_MARK: case BPF_S_ANC_QUEUE: case BPF_S_ANC_HATYPE: case BPF_S_ANC_RXHASH: case BPF_S_ANC_CPU: case BPF_S_ANC_VLAN_TAG: case BPF_S_ANC_VLAN_TAG_PRESENT: case BPF_S_RET_K: /* first instruction sets A register */ break; default: /* A = 0 */ /* lhi %r5,0 */ EMIT4(0xa7580000); } } static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter, unsigned int *addrs, int i, int last) { unsigned int K; int offset; unsigned int mask; K = filter->k; switch (filter->code) { case BPF_S_ALU_ADD_X: /* A += X */ jit->seen |= SEEN_XREG; /* ar %r5,%r12 */ EMIT2(0x1a5c); break; case BPF_S_ALU_ADD_K: /* A += K */ if (!K) break; if (K <= 16383) /* ahi %r5,<K> */ EMIT4_IMM(0xa75a0000, K); else if (test_facility(21)) /* alfi %r5,<K> */ EMIT6_IMM(0xc25b0000, K); else /* a %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5a50d000, EMIT_CONST(K)); break; case BPF_S_ALU_SUB_X: /* A -= X */ jit->seen |= SEEN_XREG; /* sr %r5,%r12 */ EMIT2(0x1b5c); break; case BPF_S_ALU_SUB_K: /* A -= K */ if (!K) break; if (K <= 16384) /* ahi %r5,-K */ EMIT4_IMM(0xa75a0000, -K); else if (test_facility(21)) /* alfi %r5,-K */ EMIT6_IMM(0xc25b0000, -K); else /* s %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5b50d000, EMIT_CONST(K)); break; case BPF_S_ALU_MUL_X: /* A *= X */ jit->seen |= SEEN_XREG; /* msr %r5,%r12 */ EMIT4(0xb252005c); break; case BPF_S_ALU_MUL_K: /* A *= K */ if (K <= 16383) /* mhi %r5,K */ EMIT4_IMM(0xa75c0000, K); else if (test_facility(34)) /* msfi %r5,<K> */ EMIT6_IMM(0xc2510000, K); else /* ms %r5,<d(K)>(%r13) */ EMIT4_DISP(0x7150d000, EMIT_CONST(K)); break; case BPF_S_ALU_DIV_X: /* A /= X */ jit->seen |= SEEN_XREG | SEEN_RET0; /* ltr %r12,%r12 */ EMIT2(0x12cc); /* jz <ret0> */ EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg)); /* lhi %r4,0 */ EMIT4(0xa7480000); /* dr %r4,%r12 */ EMIT2(0x1d4c); break; case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */ /* m %r4,<d(K)>(%r13) */ EMIT4_DISP(0x5c40d000, EMIT_CONST(K)); /* lr %r5,%r4 */ EMIT2(0x1854); break; case BPF_S_ALU_MOD_X: /* A %= X */ jit->seen |= SEEN_XREG | SEEN_RET0; /* ltr %r12,%r12 */ EMIT2(0x12cc); /* jz <ret0> */ EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg)); /* lhi %r4,0 */ EMIT4(0xa7480000); /* dr %r4,%r12 */ EMIT2(0x1d4c); /* lr %r5,%r4 */ EMIT2(0x1854); break; case BPF_S_ALU_MOD_K: /* A %= K */ /* lhi %r4,0 */ EMIT4(0xa7480000); /* d %r4,<d(K)>(%r13) */ EMIT4_DISP(0x5d40d000, EMIT_CONST(K)); /* lr %r5,%r4 */ EMIT2(0x1854); break; case BPF_S_ALU_AND_X: /* A &= X */ jit->seen |= SEEN_XREG; /* nr %r5,%r12 */ EMIT2(0x145c); break; case BPF_S_ALU_AND_K: /* A &= K */ if (test_facility(21)) /* nilf %r5,<K> */ EMIT6_IMM(0xc05b0000, K); else /* n %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5450d000, EMIT_CONST(K)); break; case BPF_S_ALU_OR_X: /* A |= X */ jit->seen |= SEEN_XREG; /* or %r5,%r12 */ EMIT2(0x165c); break; case BPF_S_ALU_OR_K: /* A |= K */ if (test_facility(21)) /* oilf %r5,<K> */ EMIT6_IMM(0xc05d0000, K); else /* o %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5650d000, EMIT_CONST(K)); break; case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */ case BPF_S_ALU_XOR_X: jit->seen |= SEEN_XREG; /* xr %r5,%r12 */ EMIT2(0x175c); break; case BPF_S_ALU_XOR_K: /* A ^= K */ if (!K) break; /* x %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5750d000, EMIT_CONST(K)); break; case BPF_S_ALU_LSH_X: /* A <<= X; */ jit->seen |= SEEN_XREG; /* sll %r5,0(%r12) */ EMIT4(0x8950c000); break; case BPF_S_ALU_LSH_K: /* A <<= K */ if (K == 0) break; /* sll %r5,K */ EMIT4_DISP(0x89500000, K); break; case BPF_S_ALU_RSH_X: /* A >>= X; */ jit->seen |= SEEN_XREG; /* srl %r5,0(%r12) */ EMIT4(0x8850c000); break; case BPF_S_ALU_RSH_K: /* A >>= K; */ if (K == 0) break; /* srl %r5,K */ EMIT4_DISP(0x88500000, K); break; case BPF_S_ALU_NEG: /* A = -A */ /* lnr %r5,%r5 */ EMIT2(0x1155); break; case BPF_S_JMP_JA: /* ip += K */ offset = addrs[i + K] + jit->start - jit->prg; EMIT4_PCREL(0xa7f40000, offset); break; case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */ mask = 0x200000; /* jh */ goto kbranch; case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */ mask = 0xa00000; /* jhe */ goto kbranch; case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */ mask = 0x800000; /* je */ kbranch: /* Emit compare if the branch targets are different */ if (filter->jt != filter->jf) { if (K <= 16383) /* chi %r5,<K> */ EMIT4_IMM(0xa75e0000, K); else if (test_facility(21)) /* clfi %r5,<K> */ EMIT6_IMM(0xc25f0000, K); else /* c %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5950d000, EMIT_CONST(K)); } branch: if (filter->jt == filter->jf) { if (filter->jt == 0) break; /* j <jt> */ offset = addrs[i + filter->jt] + jit->start - jit->prg; EMIT4_PCREL(0xa7f40000, offset); break; } if (filter->jt != 0) { /* brc <mask>,<jt> */ offset = addrs[i + filter->jt] + jit->start - jit->prg; EMIT4_PCREL(0xa7040000 | mask, offset); } if (filter->jf != 0) { /* brc <mask^15>,<jf> */ offset = addrs[i + filter->jf] + jit->start - jit->prg; EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset); } break; case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */ mask = 0x700000; /* jnz */ /* Emit test if the branch targets are different */ if (filter->jt != filter->jf) { if (K > 65535) { /* lr %r4,%r5 */ EMIT2(0x1845); /* n %r4,<d(K)>(%r13) */ EMIT4_DISP(0x5440d000, EMIT_CONST(K)); } else /* tmll %r5,K */ EMIT4_IMM(0xa7510000, K); } goto branch; case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */ mask = 0x200000; /* jh */ goto xbranch; case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */ mask = 0xa00000; /* jhe */ goto xbranch; case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */ mask = 0x800000; /* je */ xbranch: /* Emit compare if the branch targets are different */ if (filter->jt != filter->jf) { jit->seen |= SEEN_XREG; /* cr %r5,%r12 */ EMIT2(0x195c); } goto branch; case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */ mask = 0x700000; /* jnz */ /* Emit test if the branch targets are different */ if (filter->jt != filter->jf) { jit->seen |= SEEN_XREG; /* lr %r4,%r5 */ EMIT2(0x1845); /* nr %r4,%r12 */ EMIT2(0x144c); } goto branch; case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD; offset = jit->off_load_word; goto load_abs; case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF; offset = jit->off_load_half; goto load_abs; case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE; offset = jit->off_load_byte; load_abs: if ((int) K < 0) goto out; call_fn: /* lg %r1,<d(function)>(%r13) */ EMIT6_DISP(0xe310d000, 0x0004, offset); /* l %r3,<d(K)>(%r13) */ EMIT4_DISP(0x5830d000, EMIT_CONST(K)); /* basr %r8,%r1 */ EMIT2(0x0d81); /* jnz <ret0> */ EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg)); break; case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD; offset = jit->off_load_iword; goto call_fn; case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF; offset = jit->off_load_ihalf; goto call_fn; case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */ jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE; offset = jit->off_load_ibyte; goto call_fn; case BPF_S_LDX_B_MSH: /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */ jit->seen |= SEEN_RET0; if ((int) K < 0) { /* j <ret0> */ EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg)); break; } jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH; offset = jit->off_load_bmsh; goto call_fn; case BPF_S_LD_W_LEN: /* A = skb->len; */ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); /* l %r5,<d(len)>(%r2) */ EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len)); break; case BPF_S_LDX_W_LEN: /* X = skb->len; */ jit->seen |= SEEN_XREG; /* l %r12,<d(len)>(%r2) */ EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len)); break; case BPF_S_LD_IMM: /* A = K */ if (K <= 16383) /* lhi %r5,K */ EMIT4_IMM(0xa7580000, K); else if (test_facility(21)) /* llilf %r5,<K> */ EMIT6_IMM(0xc05f0000, K); else /* l %r5,<d(K)>(%r13) */ EMIT4_DISP(0x5850d000, EMIT_CONST(K)); break; case BPF_S_LDX_IMM: /* X = K */ jit->seen |= SEEN_XREG; if (K <= 16383) /* lhi %r12,<K> */ EMIT4_IMM(0xa7c80000, K); else if (test_facility(21)) /* llilf %r12,<K> */ EMIT6_IMM(0xc0cf0000, K); else /* l %r12,<d(K)>(%r13) */ EMIT4_DISP(0x58c0d000, EMIT_CONST(K)); break; case BPF_S_LD_MEM: /* A = mem[K] */ jit->seen |= SEEN_MEM; /* l %r5,<K>(%r15) */ EMIT4_DISP(0x5850f000, (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4); break; case BPF_S_LDX_MEM: /* X = mem[K] */ jit->seen |= SEEN_XREG | SEEN_MEM; /* l %r12,<K>(%r15) */ EMIT4_DISP(0x58c0f000, (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4); break; case BPF_S_MISC_TAX: /* X = A */ jit->seen |= SEEN_XREG; /* lr %r12,%r5 */ EMIT2(0x18c5); break; case BPF_S_MISC_TXA: /* A = X */ jit->seen |= SEEN_XREG; /* lr %r5,%r12 */ EMIT2(0x185c); break; case BPF_S_RET_K: if (K == 0) { jit->seen |= SEEN_RET0; if (last) break; /* j <ret0> */ EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg); } else { if (K <= 16383) /* lghi %r2,K */ EMIT4_IMM(0xa7290000, K); else /* llgf %r2,<K>(%r13) */ EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K)); /* j <exit> */ if (last && !(jit->seen & SEEN_RET0)) break; EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg); } break; case BPF_S_RET_A: /* llgfr %r2,%r5 */ EMIT4(0xb9160025); /* j <exit> */ EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg); break; case BPF_S_ST: /* mem[K] = A */ jit->seen |= SEEN_MEM; /* st %r5,<K>(%r15) */ EMIT4_DISP(0x5050f000, (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4); break; case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */ jit->seen |= SEEN_XREG | SEEN_MEM; /* st %r12,<K>(%r15) */ EMIT4_DISP(0x50c0f000, (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4); break; case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); /* lhi %r5,0 */ EMIT4(0xa7580000); /* icm %r5,3,<d(protocol)>(%r2) */ EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol)); break; case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0; * A = skb->dev->ifindex */ BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); jit->seen |= SEEN_RET0; /* lg %r1,<d(dev)>(%r2) */ EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev)); /* ltgr %r1,%r1 */ EMIT4(0xb9020011); /* jz <ret0> */ EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg); /* l %r5,<d(ifindex)>(%r1) */ EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex)); break; case BPF_S_ANC_MARK: /* A = skb->mark */ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); /* l %r5,<d(mark)>(%r2) */ EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark)); break; case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); /* lhi %r5,0 */ EMIT4(0xa7580000); /* icm %r5,3,<d(queue_mapping)>(%r2) */ EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping)); break; case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0; * A = skb->dev->type */ BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2); jit->seen |= SEEN_RET0; /* lg %r1,<d(dev)>(%r2) */ EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev)); /* ltgr %r1,%r1 */ EMIT4(0xb9020011); /* jz <ret0> */ EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg); /* lhi %r5,0 */ EMIT4(0xa7580000); /* icm %r5,3,<d(type)>(%r1) */ EMIT4_DISP(0xbf531000, offsetof(struct net_device, type)); break; case BPF_S_ANC_RXHASH: /* A = skb->rxhash */ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4); /* l %r5,<d(rxhash)>(%r2) */ EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash)); break; case BPF_S_ANC_VLAN_TAG: case BPF_S_ANC_VLAN_TAG_PRESENT: BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); /* lhi %r5,0 */ EMIT4(0xa7580000); /* icm %r5,3,<d(vlan_tci)>(%r2) */ EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci)); if (filter->code == BPF_S_ANC_VLAN_TAG) { /* nill %r5,0xefff */ EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT); } else { /* nill %r5,0x1000 */ EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT); /* srl %r5,12 */ EMIT4_DISP(0x88500000, 12); } break; case BPF_S_ANC_CPU: /* A = smp_processor_id() */ #ifdef CONFIG_SMP /* l %r5,<d(cpu_nr)> */ EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr)); #else /* lhi %r5,0 */ EMIT4(0xa7580000); #endif break; default: /* too complex, give up */ goto out; } addrs[i] = jit->prg - jit->start; return 0; out: return -1; } void bpf_jit_compile(struct sk_filter *fp) { unsigned long size, prg_len, lit_len; struct bpf_jit jit, cjit; unsigned int *addrs; int pass, i; if (!bpf_jit_enable) return; addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL); if (addrs == NULL) return; memset(&jit, 0, sizeof(cjit)); memset(&cjit, 0, sizeof(cjit)); for (pass = 0; pass < 10; pass++) { jit.prg = jit.start; jit.lit = jit.mid; bpf_jit_prologue(&jit); bpf_jit_noleaks(&jit, fp->insns); for (i = 0; i < fp->len; i++) { if (bpf_jit_insn(&jit, fp->insns + i, addrs, i, i == fp->len - 1)) goto out; } bpf_jit_epilogue(&jit); if (jit.start) { WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit); if (memcmp(&jit, &cjit, sizeof(jit)) == 0) break; } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) { prg_len = jit.prg - jit.start; lit_len = jit.lit - jit.mid; size = max_t(unsigned long, prg_len + lit_len, sizeof(struct work_struct)); if (size >= BPF_SIZE_MAX) goto out; jit.start = module_alloc(size); if (!jit.start) goto out; jit.prg = jit.mid = jit.start + prg_len; jit.lit = jit.end = jit.start + prg_len + lit_len; jit.base_ip += (unsigned long) jit.start; jit.exit_ip += (unsigned long) jit.start; jit.ret0_ip += (unsigned long) jit.start; } cjit = jit; } if (bpf_jit_enable > 1) { pr_err("flen=%d proglen=%lu pass=%d image=%p\n", fp->len, jit.end - jit.start, pass, jit.start); if (jit.start) { printk(KERN_ERR "JIT code:\n"); print_fn_code(jit.start, jit.mid - jit.start); print_hex_dump(KERN_ERR, "JIT literals:\n", DUMP_PREFIX_ADDRESS, 16, 1, jit.mid, jit.end - jit.mid, false); } } if (jit.start) fp->bpf_func = (void *) jit.start; out: kfree(addrs); } static void jit_free_defer(struct work_struct *arg) { module_free(NULL, arg); } /* run from softirq, we must use a work_struct to call * module_free() from process context */ void bpf_jit_free(struct sk_filter *fp) { struct work_struct *work; if (fp->bpf_func == sk_run_filter) return; work = (struct work_struct *)fp->bpf_func; INIT_WORK(work, jit_free_defer); schedule_work(work); }