diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kbuild | 1 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/net/Makefile | 4 | ||||
| -rw-r--r-- | arch/x86/net/bpf_jit.S | 140 | ||||
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 654 |
5 files changed, 800 insertions, 0 deletions
diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild index 0e10323..0e9dec6 100644 --- a/arch/x86/Kbuild +++ b/arch/x86/Kbuild @@ -15,3 +15,4 @@ obj-y += vdso/ obj-$(CONFIG_IA32_EMULATION) += ia32/ obj-y += platform/ +obj-y += net/ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cc6c53a..855a1bd 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -72,6 +72,7 @@ config X86 select IRQ_FORCED_THREADING select USE_GENERIC_SMP_HELPERS if SMP select ARCH_NO_SYSDEV_OPS + select HAVE_BPF_JIT if X86_64 config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS) diff --git a/arch/x86/net/Makefile b/arch/x86/net/Makefile new file mode 100644 index 0000000..90568c3 --- /dev/null +++ b/arch/x86/net/Makefile @@ -0,0 +1,4 @@ +# +# Arch-specific network modules +# +obj-$(CONFIG_BPF_JIT) += bpf_jit.o bpf_jit_comp.o diff --git a/arch/x86/net/bpf_jit.S b/arch/x86/net/bpf_jit.S new file mode 100644 index 0000000..6687022 --- /dev/null +++ b/arch/x86/net/bpf_jit.S @@ -0,0 +1,140 @@ +/* bpf_jit.S : BPF JIT helper functions + * + * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#include <linux/linkage.h> +#include <asm/dwarf2.h> + +/* + * Calling convention : + * rdi : skb pointer + * esi : offset of byte(s) to fetch in skb (can be scratched) + * r8 : copy of skb->data + * r9d : hlen = skb->len - skb->data_len + */ +#define SKBDATA %r8 + +sk_load_word_ind: + .globl sk_load_word_ind + + add %ebx,%esi /* offset += X */ +# test %esi,%esi /* if (offset < 0) goto bpf_error; */ + js bpf_error + +sk_load_word: + .globl sk_load_word + + mov %r9d,%eax # hlen + sub %esi,%eax # hlen - offset + cmp $3,%eax + jle bpf_slow_path_word + mov (SKBDATA,%rsi),%eax + bswap %eax /* ntohl() */ + ret + + +sk_load_half_ind: + .globl sk_load_half_ind + + add %ebx,%esi /* offset += X */ + js bpf_error + +sk_load_half: + .globl sk_load_half + + mov %r9d,%eax + sub %esi,%eax # hlen - offset + cmp $1,%eax + jle bpf_slow_path_half + movzwl (SKBDATA,%rsi),%eax + rol $8,%ax # ntohs() + ret + +sk_load_byte_ind: + .globl sk_load_byte_ind + add %ebx,%esi /* offset += X */ + js bpf_error + +sk_load_byte: + .globl sk_load_byte + + cmp %esi,%r9d /* if (offset >= hlen) goto bpf_slow_path_byte */ + jle bpf_slow_path_byte + movzbl (SKBDATA,%rsi),%eax + ret + +/** + * sk_load_byte_msh - BPF_S_LDX_B_MSH helper + * + * Implements BPF_S_LDX_B_MSH : ldxb 4*([offset]&0xf) + * Must preserve A accumulator (%eax) + * Inputs : %esi is the offset value, already known positive + */ +ENTRY(sk_load_byte_msh) + CFI_STARTPROC + cmp %esi,%r9d /* if (offset >= hlen) goto bpf_slow_path_byte_msh */ + jle bpf_slow_path_byte_msh + movzbl (SKBDATA,%rsi),%ebx + and $15,%bl + shl $2,%bl + ret + CFI_ENDPROC +ENDPROC(sk_load_byte_msh) + +bpf_error: +# force a return 0 from jit handler + xor %eax,%eax + mov -8(%rbp),%rbx + leaveq + ret + +/* rsi contains offset and can be scratched */ +#define bpf_slow_path_common(LEN) \ + push %rdi; /* save skb */ \ + push %r9; \ + push SKBDATA; \ +/* rsi already has offset */ \ + mov $LEN,%ecx; /* len */ \ + lea -12(%rbp),%rdx; \ + call skb_copy_bits; \ + test %eax,%eax; \ + pop SKBDATA; \ + pop %r9; \ + pop %rdi + + +bpf_slow_path_word: + bpf_slow_path_common(4) + js bpf_error + mov -12(%rbp),%eax + bswap %eax + ret + +bpf_slow_path_half: + bpf_slow_path_common(2) + js bpf_error + mov -12(%rbp),%ax + rol $8,%ax + movzwl %ax,%eax + ret + +bpf_slow_path_byte: + bpf_slow_path_common(1) + js bpf_error + movzbl -12(%rbp),%eax + ret + +bpf_slow_path_byte_msh: + xchg %eax,%ebx /* dont lose A , X is about to be scratched */ + bpf_slow_path_common(1) + js bpf_error + movzbl -12(%rbp),%eax + and $15,%al + shl $2,%al + xchg %eax,%ebx + ret diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c new file mode 100644 index 0000000..bfab3fa --- /dev/null +++ b/arch/x86/net/bpf_jit_comp.c @@ -0,0 +1,654 @@ +/* bpf_jit_comp.c : BPF JIT compiler + * + * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#include <linux/moduleloader.h> +#include <asm/cacheflush.h> +#include <linux/netdevice.h> +#include <linux/filter.h> + +/* + * Conventions : + * EAX : BPF A accumulator + * EBX : BPF X accumulator + * RDI : pointer to skb (first argument given to JIT function) + * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n) + * ECX,EDX,ESI : scratch registers + * r9d : skb->len - skb->data_len (headlen) + * r8 : skb->data + * -8(RBP) : saved RBX value + * -16(RBP)..-80(RBP) : BPF_MEMWORDS values + */ +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[]; + +static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) +{ + if (len == 1) + *ptr = bytes; + else if (len == 2) + *(u16 *)ptr = bytes; + else { + *(u32 *)ptr = bytes; + barrier(); + } + return ptr + len; +} + +#define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0) + +#define EMIT1(b1) EMIT(b1, 1) +#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2) +#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3) +#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4) +#define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0) + +#define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */ +#define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */ + +static inline bool is_imm8(int value) +{ + return value <= 127 && value >= -128; +} + +static inline bool is_near(int offset) +{ + return offset <= 127 && offset >= -128; +} + +#define EMIT_JMP(offset) \ +do { \ + if (offset) { \ + if (is_near(offset)) \ + EMIT2(0xeb, offset); /* jmp .+off8 */ \ + else \ + EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \ + } \ +} while (0) + +/* list of x86 cond jumps opcodes (. + s8) + * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32) + */ +#define X86_JB 0x72 +#define X86_JAE 0x73 +#define X86_JE 0x74 +#define X86_JNE 0x75 +#define X86_JBE 0x76 +#define X86_JA 0x77 + +#define EMIT_COND_JMP(op, offset) \ +do { \ + if (is_near(offset)) \ + EMIT2(op, offset); /* jxx .+off8 */ \ + else { \ + EMIT2(0x0f, op + 0x10); \ + EMIT(offset, 4); /* jxx .+off32 */ \ + } \ +} while (0) + +#define COND_SEL(CODE, TOP, FOP) \ + case CODE: \ + t_op = TOP; \ + f_op = FOP; \ + goto cond_branch + + +#define SEEN_DATAREF 1 /* might call external helpers */ +#define SEEN_XREG 2 /* ebx is used */ +#define SEEN_MEM 4 /* use mem[] for temporary storage */ + +static inline void bpf_flush_icache(void *start, void *end) +{ + mm_segment_t old_fs = get_fs(); + + set_fs(KERNEL_DS); + smp_wmb(); + flush_icache_range((unsigned long)start, (unsigned long)end); + set_fs(old_fs); +} + + +void bpf_jit_compile(struct sk_filter *fp) +{ + u8 temp[64]; + u8 *prog; + unsigned int proglen, oldproglen = 0; + int ilen, i; + int t_offset, f_offset; + u8 t_op, f_op, seen = 0, pass; + u8 *image = NULL; + u8 *func; + int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */ + unsigned int cleanup_addr; /* epilogue code offset */ + unsigned int *addrs; + const struct sock_filter *filter = fp->insns; + int flen = fp->len; + + if (!bpf_jit_enable) + return; + + addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL); + if (addrs == NULL) + return; + + /* Before first pass, make a rough estimation of addrs[] + * each bpf instruction is translated to less than 64 bytes + */ + for (proglen = 0, i = 0; i < flen; i++) { + proglen += 64; + addrs[i] = proglen; + } + cleanup_addr = proglen; /* epilogue address */ + + for (pass = 0; pass < 10; pass++) { + /* no prologue/epilogue for trivial filters (RET something) */ + proglen = 0; + prog = temp; + + if (seen) { + EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */ + EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */ + /* note : must save %rbx in case bpf_error is hit */ + if (seen & (SEEN_XREG | SEEN_DATAREF)) + EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */ + if (seen & SEEN_XREG) + CLEAR_X(); /* make sure we dont leek kernel memory */ + + /* + * If this filter needs to access skb data, + * loads r9 and r8 with : + * r9 = skb->len - skb->data_len + * r8 = skb->data + */ + if (seen & SEEN_DATAREF) { + if (offsetof(struct sk_buff, len) <= 127) + /* mov off8(%rdi),%r9d */ + EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len)); + else { + /* mov off32(%rdi),%r9d */ + EMIT3(0x44, 0x8b, 0x8f); + EMIT(offsetof(struct sk_buff, len), 4); + } + if (is_imm8(offsetof(struct sk_buff, data_len))) + /* sub off8(%rdi),%r9d */ + EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len)); + else { + EMIT3(0x44, 0x2b, 0x8f); + EMIT(offsetof(struct sk_buff, data_len), 4); + } + + if (is_imm8(offsetof(struct sk_buff, data))) + /* mov off8(%rdi),%r8 */ + EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data)); + else { + /* mov off32(%rdi),%r8 */ + EMIT3(0x4c, 0x8b, 0x87); + EMIT(offsetof(struct sk_buff, data), 4); + } + } + } + + switch (filter[0].code) { + case BPF_S_RET_K: + case BPF_S_LD_W_LEN: + case BPF_S_ANC_PROTOCOL: + case BPF_S_ANC_IFINDEX: + case BPF_S_ANC_MARK: + case BPF_S_ANC_RXHASH: + case BPF_S_ANC_CPU: + case BPF_S_ANC_QUEUE: + case BPF_S_LD_W_ABS: + case BPF_S_LD_H_ABS: + case BPF_S_LD_B_ABS: + /* first instruction sets A register (or is RET 'constant') */ + break; + default: + /* make sure we dont leak kernel information to user */ + CLEAR_A(); /* A = 0 */ + } + + for (i = 0; i < flen; i++) { + unsigned int K = filter[i].k; + + switch (filter[i].code) { + case BPF_S_ALU_ADD_X: /* A += X; */ + seen |= SEEN_XREG; + EMIT2(0x01, 0xd8); /* add %ebx,%eax */ + break; + case BPF_S_ALU_ADD_K: /* A += K; */ + if (!K) + break; + if (is_imm8(K)) + EMIT3(0x83, 0xc0, K); /* add imm8,%eax */ + else + EMIT1_off32(0x05, K); /* add imm32,%eax */ + break; + case BPF_S_ALU_SUB_X: /* A -= X; */ + seen |= SEEN_XREG; + EMIT2(0x29, 0xd8); /* sub %ebx,%eax */ + break; + case BPF_S_ALU_SUB_K: /* A -= K */ + if (!K) + break; + if (is_imm8(K)) + EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */ + else + EMIT1_off32(0x2d, K); /* sub imm32,%eax */ + break; + case BPF_S_ALU_MUL_X: /* A *= X; */ + seen |= SEEN_XREG; + EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */ + break; + case BPF_S_ALU_MUL_K: /* A *= K */ + if (is_imm8(K)) + EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */ + else { + EMIT2(0x69, 0xc0); /* imul imm32,%eax */ + EMIT(K, 4); + } + break; + case BPF_S_ALU_DIV_X: /* A /= X; */ + seen |= SEEN_XREG; + EMIT2(0x85, 0xdb); /* test %ebx,%ebx */ + if (pc_ret0 != -1) + EMIT_COND_JMP(X86_JE, addrs[pc_ret0] - (addrs[i] - 4)); + else { + EMIT_COND_JMP(X86_JNE, 2 + 5); + CLEAR_A(); + EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */ + } + EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */ + break; + case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */ + EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */ + EMIT(K, 4); + EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */ + break; + case BPF_S_ALU_AND_X: + seen |= SEEN_XREG; + EMIT2(0x21, 0xd8); /* and %ebx,%eax */ + break; + case BPF_S_ALU_AND_K: + if (K >= 0xFFFFFF00) { + EMIT2(0x24, K & 0xFF); /* and imm8,%al */ + } else if (K >= 0xFFFF0000) { + EMIT2(0x66, 0x25); /* and imm16,%ax */ + EMIT2(K, 2); + } else { + EMIT1_off32(0x25, K); /* and imm32,%eax */ + } + break; + case BPF_S_ALU_OR_X: + seen |= SEEN_XREG; + EMIT2(0x09, 0xd8); /* or %ebx,%eax */ + break; + case BPF_S_ALU_OR_K: + if (is_imm8(K)) + EMIT3(0x83, 0xc8, K); /* or imm8,%eax */ + else + EMIT1_off32(0x0d, K); /* or imm32,%eax */ + break; + case BPF_S_ALU_LSH_X: /* A <<= X; */ + seen |= SEEN_XREG; + EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */ + break; + case BPF_S_ALU_LSH_K: + if (K == 0) + break; + else if (K == 1) + EMIT2(0xd1, 0xe0); /* shl %eax */ + else + EMIT3(0xc1, 0xe0, K); + break; + case BPF_S_ALU_RSH_X: /* A >>= X; */ + seen |= SEEN_XREG; + EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */ + break; + case BPF_S_ALU_RSH_K: /* A >>= K; */ + if (K == 0) + break; + else if (K == 1) + EMIT2(0xd1, 0xe8); /* shr %eax */ + else + EMIT3(0xc1, 0xe8, K); + break; + case BPF_S_ALU_NEG: + EMIT2(0xf7, 0xd8); /* neg %eax */ + break; + case BPF_S_RET_K: + if (!K) { + if (pc_ret0 == -1) + pc_ret0 = i; + CLEAR_A(); + } else { + EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ + } + /* fallinto */ + case BPF_S_RET_A: + if (seen) { + if (i != flen - 1) { + EMIT_JMP(cleanup_addr - addrs[i]); + break; + } + if (seen & SEEN_XREG) + EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */ + EMIT1(0xc9); /* leaveq */ + } + EMIT1(0xc3); /* ret */ + break; + case BPF_S_MISC_TAX: /* X = A */ + seen |= SEEN_XREG; + EMIT2(0x89, 0xc3); /* mov %eax,%ebx */ + break; + case BPF_S_MISC_TXA: /* A = X */ + seen |= SEEN_XREG; + EMIT2(0x89, 0xd8); /* mov %ebx,%eax */ + break; + case BPF_S_LD_IMM: /* A = K */ + if (!K) + CLEAR_A(); + else + EMIT1_off32(0xb8, K); /* mov $imm32,%eax */ + break; + case BPF_S_LDX_IMM: /* X = K */ + seen |= SEEN_XREG; + if (!K) + CLEAR_X(); + else + EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */ + break; + case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */ + seen |= SEEN_MEM; + EMIT3(0x8b, 0x45, 0xf0 - K*4); + break; + case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */ + seen |= SEEN_XREG | SEEN_MEM; + EMIT3(0x8b, 0x5d, 0xf0 - K*4); + break; + case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */ + seen |= SEEN_MEM; + EMIT3(0x89, 0x45, 0xf0 - K*4); + break; + case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */ + seen |= SEEN_XREG | SEEN_MEM; + EMIT3(0x89, 0x5d, 0xf0 - K*4); + break; + case BPF_S_LD_W_LEN: /* A = skb->len; */ + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); + if (is_imm8(offsetof(struct sk_buff, len))) + /* mov off8(%rdi),%eax */ + EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len)); + else { + EMIT2(0x8b, 0x87); + EMIT(offsetof(struct sk_buff, len), 4); + } + break; + case BPF_S_LDX_W_LEN: /* X = skb->len; */ + seen |= SEEN_XREG; + if (is_imm8(offsetof(struct sk_buff, len))) + /* mov off8(%rdi),%ebx */ + EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len)); + else { + EMIT2(0x8b, 0x9f); + EMIT(offsetof(struct sk_buff, len), 4); + } + break; + case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */ + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); + if (is_imm8(offsetof(struct sk_buff, protocol))) { + /* movzwl off8(%rdi),%eax */ + EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol)); + } else { + EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ + EMIT(offsetof(struct sk_buff, protocol), 4); + } + EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */ + break; + case BPF_S_ANC_IFINDEX: + if (is_imm8(offsetof(struct sk_buff, dev))) { + /* movq off8(%rdi),%rax */ + EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev)); + } else { + EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */ + EMIT(offsetof(struct sk_buff, dev), 4); + } + EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */ + EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6)); + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); + EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */ + EMIT(offsetof(struct net_device, ifindex), 4); + break; + case BPF_S_ANC_MARK: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); + if (is_imm8(offsetof(struct sk_buff, mark))) { + /* mov off8(%rdi),%eax */ + EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark)); + } else { + EMIT2(0x8b, 0x87); + EMIT(offsetof(struct sk_buff, mark), 4); + } + break; + case BPF_S_ANC_RXHASH: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4); + if (is_imm8(offsetof(struct sk_buff, rxhash))) { + /* mov off8(%rdi),%eax */ + EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash)); + } else { + EMIT2(0x8b, 0x87); + EMIT(offsetof(struct sk_buff, rxhash), 4); + } + break; + case BPF_S_ANC_QUEUE: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); + if (is_imm8(offsetof(struct sk_buff, queue_mapping))) { + /* movzwl off8(%rdi),%eax */ + EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping)); + } else { + EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */ + EMIT(offsetof(struct sk_buff, queue_mapping), 4); + } + break; + case BPF_S_ANC_CPU: +#ifdef CONFIG_SMP + EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */ + EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */ +#else + CLEAR_A(); +#endif + break; + case BPF_S_LD_W_ABS: + func = sk_load_word; +common_load: seen |= SEEN_DATAREF; + if ((int)K < 0) + goto out; + t_offset = func - (image + addrs[i]); + EMIT1_off32(0xbe, K); /* mov imm32,%esi */ + EMIT1_off32(0xe8, t_offset); /* call */ + break; + case BPF_S_LD_H_ABS: + func = sk_load_half; + goto common_load; + case BPF_S_LD_B_ABS: + func = sk_load_byte; + goto common_load; + case BPF_S_LDX_B_MSH: + if ((int)K < 0) { + if (pc_ret0 != -1) { + EMIT_JMP(addrs[pc_ret0] - addrs[i]); + break; + } + CLEAR_A(); + EMIT_JMP(cleanup_addr - addrs[i]); + break; + } + seen |= SEEN_DATAREF | SEEN_XREG; + t_offset = sk_load_byte_msh - (image + addrs[i]); + EMIT1_off32(0xbe, K); /* mov imm32,%esi */ + EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */ + break; + case BPF_S_LD_W_IND: + func = sk_load_word_ind; +common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG; + t_offset = func - (image + addrs[i]); + EMIT1_off32(0xbe, K); /* mov imm32,%esi */ + EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */ + break; + case BPF_S_LD_H_IND: + func = sk_load_half_ind; + goto common_load_ind; + case BPF_S_LD_B_IND: + func = sk_load_byte_ind; + goto common_load_ind; + case BPF_S_JMP_JA: + t_offset = addrs[i + K] - addrs[i]; + EMIT_JMP(t_offset); + break; + COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE); + COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB); + COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE); + COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE); + COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE); + COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB); + COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE); + COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE); + +cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i]; + t_offset = addrs[i + filter[i].jt] - addrs[i]; + + /* same targets, can avoid doing the test :) */ + if (filter[i].jt == filter[i].jf) { + EMIT_JMP(t_offset); + break; + } + + switch (filter[i].code) { + case BPF_S_JMP_JGT_X: + case BPF_S_JMP_JGE_X: + case BPF_S_JMP_JEQ_X: + seen |= SEEN_XREG; + EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */ + break; + case BPF_S_JMP_JSET_X: + seen |= SEEN_XREG; + EMIT2(0x85, 0xd8); /* test %ebx,%eax */ + break; + case BPF_S_JMP_JEQ_K: + if (K == 0) { + EMIT2(0x85, 0xc0); /* test %eax,%eax */ + break; + } + case BPF_S_JMP_JGT_K: + case BPF_S_JMP_JGE_K: + if (K <= 127) + EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */ + else + EMIT1_off32(0x3d, K); /* cmp imm32,%eax */ + break; + case BPF_S_JMP_JSET_K: + if (K <= 0xFF) + EMIT2(0xa8, K); /* test imm8,%al */ + else if (!(K & 0xFFFF00FF)) + EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */ + else if (K <= 0xFFFF) { + EMIT2(0x66, 0xa9); /* test imm16,%ax */ + EMIT(K, 2); + } else { + EMIT1_off32(0xa9, K); /* test imm32,%eax */ + } + break; + } + if (filter[i].jt != 0) { + if (filter[i].jf) + t_offset += is_near(f_offset) ? 2 : 6; + EMIT_COND_JMP(t_op, t_offset); + if (filter[i].jf) + EMIT_JMP(f_offset); + break; + } + EMIT_COND_JMP(f_op, f_offset); + break; + default: + /* hmm, too complex filter, give up with jit compiler */ + goto out; + } + ilen = prog - temp; + if (image) { + if (unlikely(proglen + ilen > oldproglen)) { + pr_err("bpb_jit_compile fatal error\n"); + kfree(addrs); + module_free(NULL, image); + return; + } + memcpy(image + proglen, temp, ilen); + } + proglen += ilen; + addrs[i] = proglen; + prog = temp; + } + /* last bpf instruction is always a RET : + * use it to give the cleanup instruction(s) addr + */ + cleanup_addr = proglen - 1; /* ret */ + if (seen) + cleanup_addr -= 1; /* leaveq */ + if (seen & SEEN_XREG) + cleanup_addr -= 4; /* mov -8(%rbp),%rbx */ + + if (image) { + WARN_ON(proglen != oldproglen); + break; + } + if (proglen == oldproglen) { + image = module_alloc(max_t(unsigned int, + proglen, + sizeof(struct work_struct))); + if (!image) + goto out; + } + oldproglen = proglen; + } + if (bpf_jit_enable > 1) + pr_err("flen=%d proglen=%u pass=%d image=%p\n", + flen, proglen, pass, image); + + if (image) { + if (bpf_jit_enable > 1) + print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS, + 16, 1, image, proglen, false); + + bpf_flush_icache(image, image + proglen); + + fp->bpf_func = (void *)image; + } +out: + kfree(addrs); + return; +} + +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) +{ + if (fp->bpf_func != sk_run_filter) { + struct work_struct *work = (struct work_struct *)fp->bpf_func; + + INIT_WORK(work, jit_free_defer); + schedule_work(work); + } +} |
