2011-04-20 17:27:32 +08:00
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/* bpf_jit_comp.c : BPF JIT compiler
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*
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* Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/moduleloader.h>
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#include <asm/cacheflush.h>
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#include <linux/netdevice.h>
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#include <linux/filter.h>
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/*
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* Conventions :
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* EAX : BPF A accumulator
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* EBX : BPF X accumulator
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* RDI : pointer to skb (first argument given to JIT function)
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* RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
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* ECX,EDX,ESI : scratch registers
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* r9d : skb->len - skb->data_len (headlen)
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* r8 : skb->data
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* -8(RBP) : saved RBX value
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* -16(RBP)..-80(RBP) : BPF_MEMWORDS values
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*/
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int bpf_jit_enable __read_mostly;
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/*
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* assembly code in arch/x86/net/bpf_jit.S
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*/
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extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
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extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
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static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
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{
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if (len == 1)
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*ptr = bytes;
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else if (len == 2)
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*(u16 *)ptr = bytes;
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else {
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*(u32 *)ptr = bytes;
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barrier();
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}
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return ptr + len;
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}
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#define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0)
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#define EMIT1(b1) EMIT(b1, 1)
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#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
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#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
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#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
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#define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0)
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#define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
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#define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
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static inline bool is_imm8(int value)
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{
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return value <= 127 && value >= -128;
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}
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static inline bool is_near(int offset)
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{
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return offset <= 127 && offset >= -128;
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}
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#define EMIT_JMP(offset) \
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do { \
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if (offset) { \
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if (is_near(offset)) \
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EMIT2(0xeb, offset); /* jmp .+off8 */ \
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else \
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EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \
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} \
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} while (0)
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/* list of x86 cond jumps opcodes (. + s8)
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* Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
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*/
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#define X86_JB 0x72
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#define X86_JAE 0x73
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#define X86_JE 0x74
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#define X86_JNE 0x75
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#define X86_JBE 0x76
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#define X86_JA 0x77
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#define EMIT_COND_JMP(op, offset) \
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do { \
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if (is_near(offset)) \
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EMIT2(op, offset); /* jxx .+off8 */ \
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else { \
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EMIT2(0x0f, op + 0x10); \
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EMIT(offset, 4); /* jxx .+off32 */ \
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} \
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} while (0)
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#define COND_SEL(CODE, TOP, FOP) \
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case CODE: \
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t_op = TOP; \
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f_op = FOP; \
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goto cond_branch
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#define SEEN_DATAREF 1 /* might call external helpers */
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#define SEEN_XREG 2 /* ebx is used */
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#define SEEN_MEM 4 /* use mem[] for temporary storage */
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static inline void bpf_flush_icache(void *start, void *end)
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{
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mm_segment_t old_fs = get_fs();
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set_fs(KERNEL_DS);
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smp_wmb();
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flush_icache_range((unsigned long)start, (unsigned long)end);
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set_fs(old_fs);
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}
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void bpf_jit_compile(struct sk_filter *fp)
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{
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u8 temp[64];
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u8 *prog;
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unsigned int proglen, oldproglen = 0;
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int ilen, i;
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int t_offset, f_offset;
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u8 t_op, f_op, seen = 0, pass;
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u8 *image = NULL;
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u8 *func;
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int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
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unsigned int cleanup_addr; /* epilogue code offset */
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unsigned int *addrs;
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const struct sock_filter *filter = fp->insns;
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int flen = fp->len;
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if (!bpf_jit_enable)
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return;
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addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
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if (addrs == NULL)
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return;
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/* Before first pass, make a rough estimation of addrs[]
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* each bpf instruction is translated to less than 64 bytes
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*/
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for (proglen = 0, i = 0; i < flen; i++) {
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proglen += 64;
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addrs[i] = proglen;
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}
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cleanup_addr = proglen; /* epilogue address */
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for (pass = 0; pass < 10; pass++) {
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/* no prologue/epilogue for trivial filters (RET something) */
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proglen = 0;
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prog = temp;
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if (seen) {
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EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
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EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */
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/* note : must save %rbx in case bpf_error is hit */
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if (seen & (SEEN_XREG | SEEN_DATAREF))
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EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
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if (seen & SEEN_XREG)
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CLEAR_X(); /* make sure we dont leek kernel memory */
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/*
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* If this filter needs to access skb data,
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* loads r9 and r8 with :
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* r9 = skb->len - skb->data_len
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* r8 = skb->data
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*/
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if (seen & SEEN_DATAREF) {
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if (offsetof(struct sk_buff, len) <= 127)
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/* mov off8(%rdi),%r9d */
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EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
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else {
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/* mov off32(%rdi),%r9d */
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EMIT3(0x44, 0x8b, 0x8f);
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EMIT(offsetof(struct sk_buff, len), 4);
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}
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if (is_imm8(offsetof(struct sk_buff, data_len)))
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/* sub off8(%rdi),%r9d */
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EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
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else {
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EMIT3(0x44, 0x2b, 0x8f);
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EMIT(offsetof(struct sk_buff, data_len), 4);
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}
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if (is_imm8(offsetof(struct sk_buff, data)))
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/* mov off8(%rdi),%r8 */
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EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
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else {
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/* mov off32(%rdi),%r8 */
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EMIT3(0x4c, 0x8b, 0x87);
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EMIT(offsetof(struct sk_buff, data), 4);
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}
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}
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}
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switch (filter[0].code) {
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case BPF_S_RET_K:
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case BPF_S_LD_W_LEN:
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case BPF_S_ANC_PROTOCOL:
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case BPF_S_ANC_IFINDEX:
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case BPF_S_ANC_MARK:
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case BPF_S_ANC_RXHASH:
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case BPF_S_ANC_CPU:
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case BPF_S_ANC_QUEUE:
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case BPF_S_LD_W_ABS:
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case BPF_S_LD_H_ABS:
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case BPF_S_LD_B_ABS:
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/* first instruction sets A register (or is RET 'constant') */
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break;
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default:
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/* make sure we dont leak kernel information to user */
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CLEAR_A(); /* A = 0 */
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}
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for (i = 0; i < flen; i++) {
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unsigned int K = filter[i].k;
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switch (filter[i].code) {
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case BPF_S_ALU_ADD_X: /* A += X; */
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seen |= SEEN_XREG;
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EMIT2(0x01, 0xd8); /* add %ebx,%eax */
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break;
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case BPF_S_ALU_ADD_K: /* A += K; */
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if (!K)
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break;
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if (is_imm8(K))
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EMIT3(0x83, 0xc0, K); /* add imm8,%eax */
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else
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EMIT1_off32(0x05, K); /* add imm32,%eax */
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break;
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case BPF_S_ALU_SUB_X: /* A -= X; */
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seen |= SEEN_XREG;
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EMIT2(0x29, 0xd8); /* sub %ebx,%eax */
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break;
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case BPF_S_ALU_SUB_K: /* A -= K */
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if (!K)
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break;
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if (is_imm8(K))
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EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
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else
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EMIT1_off32(0x2d, K); /* sub imm32,%eax */
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break;
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case BPF_S_ALU_MUL_X: /* A *= X; */
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seen |= SEEN_XREG;
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EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */
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break;
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case BPF_S_ALU_MUL_K: /* A *= K */
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if (is_imm8(K))
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EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
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else {
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EMIT2(0x69, 0xc0); /* imul imm32,%eax */
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EMIT(K, 4);
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}
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break;
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case BPF_S_ALU_DIV_X: /* A /= X; */
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seen |= SEEN_XREG;
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EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
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if (pc_ret0 != -1)
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EMIT_COND_JMP(X86_JE, addrs[pc_ret0] - (addrs[i] - 4));
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else {
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EMIT_COND_JMP(X86_JNE, 2 + 5);
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CLEAR_A();
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EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
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}
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EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
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break;
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case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
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EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
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EMIT(K, 4);
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EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
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break;
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case BPF_S_ALU_AND_X:
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seen |= SEEN_XREG;
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EMIT2(0x21, 0xd8); /* and %ebx,%eax */
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break;
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case BPF_S_ALU_AND_K:
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if (K >= 0xFFFFFF00) {
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EMIT2(0x24, K & 0xFF); /* and imm8,%al */
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} else if (K >= 0xFFFF0000) {
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EMIT2(0x66, 0x25); /* and imm16,%ax */
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EMIT2(K, 2);
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} else {
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EMIT1_off32(0x25, K); /* and imm32,%eax */
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}
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break;
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case BPF_S_ALU_OR_X:
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seen |= SEEN_XREG;
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EMIT2(0x09, 0xd8); /* or %ebx,%eax */
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break;
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case BPF_S_ALU_OR_K:
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if (is_imm8(K))
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EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
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else
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EMIT1_off32(0x0d, K); /* or imm32,%eax */
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break;
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|
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) {
|
2011-12-17 19:39:08 +08:00
|
|
|
if (filter[i].jf && f_offset)
|
|
|
|
|
t_offset += is_near(f_offset) ? 2 : 5;
|
2011-04-20 17:27:32 +08:00
|
|
|
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);
|
|
|
|
|
}
|
|
|
|
|
}
|
