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![Eric Dumazet](/assets/img/avatar_default.png)
Saves 4 bytes replacing following instructions : lea rax, [rsi + rdx * 8 + offsetof(...)] mov rax, qword ptr [rax] cmp rax, 0 by : mov rax, [rsi + rdx * 8 + offsetof(...)] test rax, rax Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
1207 lines
31 KiB
C
1207 lines
31 KiB
C
/* bpf_jit_comp.c : BPF JIT compiler
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*
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* Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
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* Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.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/netdevice.h>
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#include <linux/filter.h>
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#include <linux/if_vlan.h>
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#include <asm/cacheflush.h>
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#include <asm/set_memory.h>
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#include <linux/bpf.h>
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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[];
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extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
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extern u8 sk_load_byte_positive_offset[];
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extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
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extern u8 sk_load_byte_negative_offset[];
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static 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) \
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do { prog = emit_code(prog, bytes, len); cnt += 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) \
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do {EMIT1(b1); EMIT(off, 4); } while (0)
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#define EMIT2_off32(b1, b2, off) \
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do {EMIT2(b1, b2); EMIT(off, 4); } while (0)
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#define EMIT3_off32(b1, b2, b3, off) \
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do {EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
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#define EMIT4_off32(b1, b2, b3, b4, off) \
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do {EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
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static 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 bool is_simm32(s64 value)
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{
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return value == (s64) (s32) value;
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}
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/* mov dst, src */
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#define EMIT_mov(DST, SRC) \
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do {if (DST != SRC) \
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EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
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} while (0)
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static int bpf_size_to_x86_bytes(int bpf_size)
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{
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if (bpf_size == BPF_W)
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return 4;
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else if (bpf_size == BPF_H)
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return 2;
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else if (bpf_size == BPF_B)
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return 1;
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else if (bpf_size == BPF_DW)
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return 4; /* imm32 */
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else
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return 0;
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}
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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 X86_JL 0x7C
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#define X86_JGE 0x7D
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#define X86_JLE 0x7E
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#define X86_JG 0x7F
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static 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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#define CHOOSE_LOAD_FUNC(K, func) \
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((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
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/* pick a register outside of BPF range for JIT internal work */
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#define AUX_REG (MAX_BPF_JIT_REG + 1)
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/* The following table maps BPF registers to x64 registers.
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*
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* x64 register r12 is unused, since if used as base address
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* register in load/store instructions, it always needs an
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* extra byte of encoding and is callee saved.
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*
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* r9 caches skb->len - skb->data_len
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* r10 caches skb->data, and used for blinding (if enabled)
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*/
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static const int reg2hex[] = {
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[BPF_REG_0] = 0, /* rax */
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[BPF_REG_1] = 7, /* rdi */
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[BPF_REG_2] = 6, /* rsi */
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[BPF_REG_3] = 2, /* rdx */
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[BPF_REG_4] = 1, /* rcx */
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[BPF_REG_5] = 0, /* r8 */
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[BPF_REG_6] = 3, /* rbx callee saved */
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[BPF_REG_7] = 5, /* r13 callee saved */
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[BPF_REG_8] = 6, /* r14 callee saved */
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[BPF_REG_9] = 7, /* r15 callee saved */
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[BPF_REG_FP] = 5, /* rbp readonly */
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[BPF_REG_AX] = 2, /* r10 temp register */
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[AUX_REG] = 3, /* r11 temp register */
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};
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/* is_ereg() == true if BPF register 'reg' maps to x64 r8..r15
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* which need extra byte of encoding.
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* rax,rcx,...,rbp have simpler encoding
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*/
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static bool is_ereg(u32 reg)
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{
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return (1 << reg) & (BIT(BPF_REG_5) |
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BIT(AUX_REG) |
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BIT(BPF_REG_7) |
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BIT(BPF_REG_8) |
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BIT(BPF_REG_9) |
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BIT(BPF_REG_AX));
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}
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/* add modifiers if 'reg' maps to x64 registers r8..r15 */
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static u8 add_1mod(u8 byte, u32 reg)
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{
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if (is_ereg(reg))
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byte |= 1;
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return byte;
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}
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static u8 add_2mod(u8 byte, u32 r1, u32 r2)
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{
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if (is_ereg(r1))
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byte |= 1;
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if (is_ereg(r2))
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byte |= 4;
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return byte;
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}
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/* encode 'dst_reg' register into x64 opcode 'byte' */
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static u8 add_1reg(u8 byte, u32 dst_reg)
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{
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return byte + reg2hex[dst_reg];
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}
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/* encode 'dst_reg' and 'src_reg' registers into x64 opcode 'byte' */
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static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
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{
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return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
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}
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static void jit_fill_hole(void *area, unsigned int size)
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{
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/* fill whole space with int3 instructions */
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memset(area, 0xcc, size);
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}
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struct jit_context {
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int cleanup_addr; /* epilogue code offset */
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bool seen_ld_abs;
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bool seen_ax_reg;
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};
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/* maximum number of bytes emitted while JITing one eBPF insn */
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#define BPF_MAX_INSN_SIZE 128
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#define BPF_INSN_SAFETY 64
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#define AUX_STACK_SPACE \
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(32 /* space for rbx, r13, r14, r15 */ + \
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8 /* space for skb_copy_bits() buffer */)
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#define PROLOGUE_SIZE 37
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/* emit x64 prologue code for BPF program and check it's size.
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* bpf_tail_call helper will skip it while jumping into another program
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*/
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static void emit_prologue(u8 **pprog, u32 stack_depth)
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{
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u8 *prog = *pprog;
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int cnt = 0;
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EMIT1(0x55); /* push rbp */
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EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
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/* sub rsp, rounded_stack_depth + AUX_STACK_SPACE */
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EMIT3_off32(0x48, 0x81, 0xEC,
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round_up(stack_depth, 8) + AUX_STACK_SPACE);
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/* sub rbp, AUX_STACK_SPACE */
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EMIT4(0x48, 0x83, 0xED, AUX_STACK_SPACE);
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/* all classic BPF filters use R6(rbx) save it */
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/* mov qword ptr [rbp+0],rbx */
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EMIT4(0x48, 0x89, 0x5D, 0);
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/* bpf_convert_filter() maps classic BPF register X to R7 and uses R8
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* as temporary, so all tcpdump filters need to spill/fill R7(r13) and
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* R8(r14). R9(r15) spill could be made conditional, but there is only
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* one 'bpf_error' return path out of helper functions inside bpf_jit.S
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* The overhead of extra spill is negligible for any filter other
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* than synthetic ones. Therefore not worth adding complexity.
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*/
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/* mov qword ptr [rbp+8],r13 */
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EMIT4(0x4C, 0x89, 0x6D, 8);
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/* mov qword ptr [rbp+16],r14 */
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EMIT4(0x4C, 0x89, 0x75, 16);
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/* mov qword ptr [rbp+24],r15 */
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EMIT4(0x4C, 0x89, 0x7D, 24);
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/* Clear the tail call counter (tail_call_cnt): for eBPF tail calls
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* we need to reset the counter to 0. It's done in two instructions,
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* resetting rax register to 0 (xor on eax gets 0 extended), and
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* moving it to the counter location.
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*/
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/* xor eax, eax */
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EMIT2(0x31, 0xc0);
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/* mov qword ptr [rbp+32], rax */
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EMIT4(0x48, 0x89, 0x45, 32);
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BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
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*pprog = prog;
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}
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/* generate the following code:
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* ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
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* if (index >= array->map.max_entries)
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* goto out;
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* if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
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* goto out;
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* prog = array->ptrs[index];
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* if (prog == NULL)
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* goto out;
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* goto *(prog->bpf_func + prologue_size);
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* out:
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*/
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static void emit_bpf_tail_call(u8 **pprog)
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{
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u8 *prog = *pprog;
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int label1, label2, label3;
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int cnt = 0;
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/* rdi - pointer to ctx
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* rsi - pointer to bpf_array
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* rdx - index in bpf_array
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*/
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/* if (index >= array->map.max_entries)
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* goto out;
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*/
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EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */
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offsetof(struct bpf_array, map.max_entries));
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EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */
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#define OFFSET1 43 /* number of bytes to jump */
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EMIT2(X86_JBE, OFFSET1); /* jbe out */
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label1 = cnt;
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/* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
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* goto out;
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*/
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EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */
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EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
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#define OFFSET2 32
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EMIT2(X86_JA, OFFSET2); /* ja out */
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label2 = cnt;
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EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
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EMIT2_off32(0x89, 0x85, 36); /* mov dword ptr [rbp + 36], eax */
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/* prog = array->ptrs[index]; */
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EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */
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offsetof(struct bpf_array, ptrs));
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/* if (prog == NULL)
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* goto out;
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*/
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EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
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#define OFFSET3 10
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EMIT2(X86_JE, OFFSET3); /* je out */
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label3 = cnt;
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/* goto *(prog->bpf_func + prologue_size); */
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EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
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offsetof(struct bpf_prog, bpf_func));
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EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
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/* now we're ready to jump into next BPF program
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* rdi == ctx (1st arg)
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* rax == prog->bpf_func + prologue_size
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*/
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EMIT2(0xFF, 0xE0); /* jmp rax */
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/* out: */
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BUILD_BUG_ON(cnt - label1 != OFFSET1);
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BUILD_BUG_ON(cnt - label2 != OFFSET2);
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BUILD_BUG_ON(cnt - label3 != OFFSET3);
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*pprog = prog;
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}
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static void emit_load_skb_data_hlen(u8 **pprog)
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{
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u8 *prog = *pprog;
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int cnt = 0;
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/* r9d = skb->len - skb->data_len (headlen)
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* r10 = skb->data
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*/
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/* mov %r9d, off32(%rdi) */
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EMIT3_off32(0x44, 0x8b, 0x8f, offsetof(struct sk_buff, len));
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/* sub %r9d, off32(%rdi) */
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EMIT3_off32(0x44, 0x2b, 0x8f, offsetof(struct sk_buff, data_len));
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/* mov %r10, off32(%rdi) */
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EMIT3_off32(0x4c, 0x8b, 0x97, offsetof(struct sk_buff, data));
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*pprog = prog;
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}
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static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
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int oldproglen, struct jit_context *ctx)
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{
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struct bpf_insn *insn = bpf_prog->insnsi;
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int insn_cnt = bpf_prog->len;
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bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0);
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bool seen_ax_reg = ctx->seen_ax_reg | (oldproglen == 0);
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bool seen_exit = false;
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u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
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int i, cnt = 0;
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int proglen = 0;
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u8 *prog = temp;
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emit_prologue(&prog, bpf_prog->aux->stack_depth);
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if (seen_ld_abs)
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emit_load_skb_data_hlen(&prog);
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for (i = 0; i < insn_cnt; i++, insn++) {
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const s32 imm32 = insn->imm;
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u32 dst_reg = insn->dst_reg;
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u32 src_reg = insn->src_reg;
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u8 b1 = 0, b2 = 0, b3 = 0;
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s64 jmp_offset;
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u8 jmp_cond;
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bool reload_skb_data;
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int ilen;
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u8 *func;
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if (dst_reg == BPF_REG_AX || src_reg == BPF_REG_AX)
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ctx->seen_ax_reg = seen_ax_reg = true;
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switch (insn->code) {
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/* ALU */
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case BPF_ALU | BPF_ADD | BPF_X:
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case BPF_ALU | BPF_SUB | BPF_X:
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case BPF_ALU | BPF_AND | BPF_X:
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case BPF_ALU | BPF_OR | BPF_X:
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case BPF_ALU | BPF_XOR | BPF_X:
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case BPF_ALU64 | BPF_ADD | BPF_X:
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case BPF_ALU64 | BPF_SUB | BPF_X:
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case BPF_ALU64 | BPF_AND | BPF_X:
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case BPF_ALU64 | BPF_OR | BPF_X:
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case BPF_ALU64 | BPF_XOR | BPF_X:
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switch (BPF_OP(insn->code)) {
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case BPF_ADD: b2 = 0x01; break;
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case BPF_SUB: b2 = 0x29; break;
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case BPF_AND: b2 = 0x21; break;
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case BPF_OR: b2 = 0x09; break;
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case BPF_XOR: b2 = 0x31; break;
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}
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if (BPF_CLASS(insn->code) == BPF_ALU64)
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EMIT1(add_2mod(0x48, dst_reg, src_reg));
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else if (is_ereg(dst_reg) || is_ereg(src_reg))
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EMIT1(add_2mod(0x40, dst_reg, src_reg));
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EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
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break;
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/* mov dst, src */
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case BPF_ALU64 | BPF_MOV | BPF_X:
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EMIT_mov(dst_reg, src_reg);
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break;
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/* mov32 dst, src */
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case BPF_ALU | BPF_MOV | BPF_X:
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if (is_ereg(dst_reg) || is_ereg(src_reg))
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EMIT1(add_2mod(0x40, dst_reg, src_reg));
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EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
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break;
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/* neg dst */
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case BPF_ALU | BPF_NEG:
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case BPF_ALU64 | BPF_NEG:
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if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
else if (is_ereg(dst_reg))
|
|
EMIT1(add_1mod(0x40, dst_reg));
|
|
EMIT2(0xF7, add_1reg(0xD8, dst_reg));
|
|
break;
|
|
|
|
case BPF_ALU | BPF_ADD | BPF_K:
|
|
case BPF_ALU | BPF_SUB | BPF_K:
|
|
case BPF_ALU | BPF_AND | BPF_K:
|
|
case BPF_ALU | BPF_OR | BPF_K:
|
|
case BPF_ALU | BPF_XOR | BPF_K:
|
|
case BPF_ALU64 | BPF_ADD | BPF_K:
|
|
case BPF_ALU64 | BPF_SUB | BPF_K:
|
|
case BPF_ALU64 | BPF_AND | BPF_K:
|
|
case BPF_ALU64 | BPF_OR | BPF_K:
|
|
case BPF_ALU64 | BPF_XOR | BPF_K:
|
|
if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
else if (is_ereg(dst_reg))
|
|
EMIT1(add_1mod(0x40, dst_reg));
|
|
|
|
switch (BPF_OP(insn->code)) {
|
|
case BPF_ADD: b3 = 0xC0; break;
|
|
case BPF_SUB: b3 = 0xE8; break;
|
|
case BPF_AND: b3 = 0xE0; break;
|
|
case BPF_OR: b3 = 0xC8; break;
|
|
case BPF_XOR: b3 = 0xF0; break;
|
|
}
|
|
|
|
if (is_imm8(imm32))
|
|
EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
|
|
else
|
|
EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
|
|
break;
|
|
|
|
case BPF_ALU64 | BPF_MOV | BPF_K:
|
|
/* optimization: if imm32 is positive,
|
|
* use 'mov eax, imm32' (which zero-extends imm32)
|
|
* to save 2 bytes
|
|
*/
|
|
if (imm32 < 0) {
|
|
/* 'mov rax, imm32' sign extends imm32 */
|
|
b1 = add_1mod(0x48, dst_reg);
|
|
b2 = 0xC7;
|
|
b3 = 0xC0;
|
|
EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32);
|
|
break;
|
|
}
|
|
|
|
case BPF_ALU | BPF_MOV | BPF_K:
|
|
/* optimization: if imm32 is zero, use 'xor <dst>,<dst>'
|
|
* to save 3 bytes.
|
|
*/
|
|
if (imm32 == 0) {
|
|
if (is_ereg(dst_reg))
|
|
EMIT1(add_2mod(0x40, dst_reg, dst_reg));
|
|
b2 = 0x31; /* xor */
|
|
b3 = 0xC0;
|
|
EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
|
|
break;
|
|
}
|
|
|
|
/* mov %eax, imm32 */
|
|
if (is_ereg(dst_reg))
|
|
EMIT1(add_1mod(0x40, dst_reg));
|
|
EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
|
|
break;
|
|
|
|
case BPF_LD | BPF_IMM | BPF_DW:
|
|
/* optimization: if imm64 is zero, use 'xor <dst>,<dst>'
|
|
* to save 7 bytes.
|
|
*/
|
|
if (insn[0].imm == 0 && insn[1].imm == 0) {
|
|
b1 = add_2mod(0x48, dst_reg, dst_reg);
|
|
b2 = 0x31; /* xor */
|
|
b3 = 0xC0;
|
|
EMIT3(b1, b2, add_2reg(b3, dst_reg, dst_reg));
|
|
|
|
insn++;
|
|
i++;
|
|
break;
|
|
}
|
|
|
|
/* movabsq %rax, imm64 */
|
|
EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
|
|
EMIT(insn[0].imm, 4);
|
|
EMIT(insn[1].imm, 4);
|
|
|
|
insn++;
|
|
i++;
|
|
break;
|
|
|
|
/* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
|
|
case BPF_ALU | BPF_MOD | BPF_X:
|
|
case BPF_ALU | BPF_DIV | BPF_X:
|
|
case BPF_ALU | BPF_MOD | BPF_K:
|
|
case BPF_ALU | BPF_DIV | BPF_K:
|
|
case BPF_ALU64 | BPF_MOD | BPF_X:
|
|
case BPF_ALU64 | BPF_DIV | BPF_X:
|
|
case BPF_ALU64 | BPF_MOD | BPF_K:
|
|
case BPF_ALU64 | BPF_DIV | BPF_K:
|
|
EMIT1(0x50); /* push rax */
|
|
EMIT1(0x52); /* push rdx */
|
|
|
|
if (BPF_SRC(insn->code) == BPF_X)
|
|
/* mov r11, src_reg */
|
|
EMIT_mov(AUX_REG, src_reg);
|
|
else
|
|
/* mov r11, imm32 */
|
|
EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
|
|
|
|
/* mov rax, dst_reg */
|
|
EMIT_mov(BPF_REG_0, dst_reg);
|
|
|
|
/* xor edx, edx
|
|
* equivalent to 'xor rdx, rdx', but one byte less
|
|
*/
|
|
EMIT2(0x31, 0xd2);
|
|
|
|
if (BPF_SRC(insn->code) == BPF_X) {
|
|
/* if (src_reg == 0) return 0 */
|
|
|
|
/* cmp r11, 0 */
|
|
EMIT4(0x49, 0x83, 0xFB, 0x00);
|
|
|
|
/* jne .+9 (skip over pop, pop, xor and jmp) */
|
|
EMIT2(X86_JNE, 1 + 1 + 2 + 5);
|
|
EMIT1(0x5A); /* pop rdx */
|
|
EMIT1(0x58); /* pop rax */
|
|
EMIT2(0x31, 0xc0); /* xor eax, eax */
|
|
|
|
/* jmp cleanup_addr
|
|
* addrs[i] - 11, because there are 11 bytes
|
|
* after this insn: div, mov, pop, pop, mov
|
|
*/
|
|
jmp_offset = ctx->cleanup_addr - (addrs[i] - 11);
|
|
EMIT1_off32(0xE9, jmp_offset);
|
|
}
|
|
|
|
if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
/* div r11 */
|
|
EMIT3(0x49, 0xF7, 0xF3);
|
|
else
|
|
/* div r11d */
|
|
EMIT3(0x41, 0xF7, 0xF3);
|
|
|
|
if (BPF_OP(insn->code) == BPF_MOD)
|
|
/* mov r11, rdx */
|
|
EMIT3(0x49, 0x89, 0xD3);
|
|
else
|
|
/* mov r11, rax */
|
|
EMIT3(0x49, 0x89, 0xC3);
|
|
|
|
EMIT1(0x5A); /* pop rdx */
|
|
EMIT1(0x58); /* pop rax */
|
|
|
|
/* mov dst_reg, r11 */
|
|
EMIT_mov(dst_reg, AUX_REG);
|
|
break;
|
|
|
|
case BPF_ALU | BPF_MUL | BPF_K:
|
|
case BPF_ALU | BPF_MUL | BPF_X:
|
|
case BPF_ALU64 | BPF_MUL | BPF_K:
|
|
case BPF_ALU64 | BPF_MUL | BPF_X:
|
|
EMIT1(0x50); /* push rax */
|
|
EMIT1(0x52); /* push rdx */
|
|
|
|
/* mov r11, dst_reg */
|
|
EMIT_mov(AUX_REG, dst_reg);
|
|
|
|
if (BPF_SRC(insn->code) == BPF_X)
|
|
/* mov rax, src_reg */
|
|
EMIT_mov(BPF_REG_0, src_reg);
|
|
else
|
|
/* mov rax, imm32 */
|
|
EMIT3_off32(0x48, 0xC7, 0xC0, imm32);
|
|
|
|
if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
EMIT1(add_1mod(0x48, AUX_REG));
|
|
else if (is_ereg(AUX_REG))
|
|
EMIT1(add_1mod(0x40, AUX_REG));
|
|
/* mul(q) r11 */
|
|
EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
|
|
|
|
/* mov r11, rax */
|
|
EMIT_mov(AUX_REG, BPF_REG_0);
|
|
|
|
EMIT1(0x5A); /* pop rdx */
|
|
EMIT1(0x58); /* pop rax */
|
|
|
|
/* mov dst_reg, r11 */
|
|
EMIT_mov(dst_reg, AUX_REG);
|
|
break;
|
|
|
|
/* shifts */
|
|
case BPF_ALU | BPF_LSH | BPF_K:
|
|
case BPF_ALU | BPF_RSH | BPF_K:
|
|
case BPF_ALU | BPF_ARSH | BPF_K:
|
|
case BPF_ALU64 | BPF_LSH | BPF_K:
|
|
case BPF_ALU64 | BPF_RSH | BPF_K:
|
|
case BPF_ALU64 | BPF_ARSH | BPF_K:
|
|
if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
else if (is_ereg(dst_reg))
|
|
EMIT1(add_1mod(0x40, dst_reg));
|
|
|
|
switch (BPF_OP(insn->code)) {
|
|
case BPF_LSH: b3 = 0xE0; break;
|
|
case BPF_RSH: b3 = 0xE8; break;
|
|
case BPF_ARSH: b3 = 0xF8; break;
|
|
}
|
|
EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
|
|
break;
|
|
|
|
case BPF_ALU | BPF_LSH | BPF_X:
|
|
case BPF_ALU | BPF_RSH | BPF_X:
|
|
case BPF_ALU | BPF_ARSH | BPF_X:
|
|
case BPF_ALU64 | BPF_LSH | BPF_X:
|
|
case BPF_ALU64 | BPF_RSH | BPF_X:
|
|
case BPF_ALU64 | BPF_ARSH | BPF_X:
|
|
|
|
/* check for bad case when dst_reg == rcx */
|
|
if (dst_reg == BPF_REG_4) {
|
|
/* mov r11, dst_reg */
|
|
EMIT_mov(AUX_REG, dst_reg);
|
|
dst_reg = AUX_REG;
|
|
}
|
|
|
|
if (src_reg != BPF_REG_4) { /* common case */
|
|
EMIT1(0x51); /* push rcx */
|
|
|
|
/* mov rcx, src_reg */
|
|
EMIT_mov(BPF_REG_4, src_reg);
|
|
}
|
|
|
|
/* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
|
|
if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
else if (is_ereg(dst_reg))
|
|
EMIT1(add_1mod(0x40, dst_reg));
|
|
|
|
switch (BPF_OP(insn->code)) {
|
|
case BPF_LSH: b3 = 0xE0; break;
|
|
case BPF_RSH: b3 = 0xE8; break;
|
|
case BPF_ARSH: b3 = 0xF8; break;
|
|
}
|
|
EMIT2(0xD3, add_1reg(b3, dst_reg));
|
|
|
|
if (src_reg != BPF_REG_4)
|
|
EMIT1(0x59); /* pop rcx */
|
|
|
|
if (insn->dst_reg == BPF_REG_4)
|
|
/* mov dst_reg, r11 */
|
|
EMIT_mov(insn->dst_reg, AUX_REG);
|
|
break;
|
|
|
|
case BPF_ALU | BPF_END | BPF_FROM_BE:
|
|
switch (imm32) {
|
|
case 16:
|
|
/* emit 'ror %ax, 8' to swap lower 2 bytes */
|
|
EMIT1(0x66);
|
|
if (is_ereg(dst_reg))
|
|
EMIT1(0x41);
|
|
EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
|
|
|
|
/* emit 'movzwl eax, ax' */
|
|
if (is_ereg(dst_reg))
|
|
EMIT3(0x45, 0x0F, 0xB7);
|
|
else
|
|
EMIT2(0x0F, 0xB7);
|
|
EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
|
|
break;
|
|
case 32:
|
|
/* emit 'bswap eax' to swap lower 4 bytes */
|
|
if (is_ereg(dst_reg))
|
|
EMIT2(0x41, 0x0F);
|
|
else
|
|
EMIT1(0x0F);
|
|
EMIT1(add_1reg(0xC8, dst_reg));
|
|
break;
|
|
case 64:
|
|
/* emit 'bswap rax' to swap 8 bytes */
|
|
EMIT3(add_1mod(0x48, dst_reg), 0x0F,
|
|
add_1reg(0xC8, dst_reg));
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case BPF_ALU | BPF_END | BPF_FROM_LE:
|
|
switch (imm32) {
|
|
case 16:
|
|
/* emit 'movzwl eax, ax' to zero extend 16-bit
|
|
* into 64 bit
|
|
*/
|
|
if (is_ereg(dst_reg))
|
|
EMIT3(0x45, 0x0F, 0xB7);
|
|
else
|
|
EMIT2(0x0F, 0xB7);
|
|
EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
|
|
break;
|
|
case 32:
|
|
/* emit 'mov eax, eax' to clear upper 32-bits */
|
|
if (is_ereg(dst_reg))
|
|
EMIT1(0x45);
|
|
EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
|
|
break;
|
|
case 64:
|
|
/* nop */
|
|
break;
|
|
}
|
|
break;
|
|
|
|
/* ST: *(u8*)(dst_reg + off) = imm */
|
|
case BPF_ST | BPF_MEM | BPF_B:
|
|
if (is_ereg(dst_reg))
|
|
EMIT2(0x41, 0xC6);
|
|
else
|
|
EMIT1(0xC6);
|
|
goto st;
|
|
case BPF_ST | BPF_MEM | BPF_H:
|
|
if (is_ereg(dst_reg))
|
|
EMIT3(0x66, 0x41, 0xC7);
|
|
else
|
|
EMIT2(0x66, 0xC7);
|
|
goto st;
|
|
case BPF_ST | BPF_MEM | BPF_W:
|
|
if (is_ereg(dst_reg))
|
|
EMIT2(0x41, 0xC7);
|
|
else
|
|
EMIT1(0xC7);
|
|
goto st;
|
|
case BPF_ST | BPF_MEM | BPF_DW:
|
|
EMIT2(add_1mod(0x48, dst_reg), 0xC7);
|
|
|
|
st: if (is_imm8(insn->off))
|
|
EMIT2(add_1reg(0x40, dst_reg), insn->off);
|
|
else
|
|
EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);
|
|
|
|
EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
|
|
break;
|
|
|
|
/* STX: *(u8*)(dst_reg + off) = src_reg */
|
|
case BPF_STX | BPF_MEM | BPF_B:
|
|
/* emit 'mov byte ptr [rax + off], al' */
|
|
if (is_ereg(dst_reg) || is_ereg(src_reg) ||
|
|
/* have to add extra byte for x86 SIL, DIL regs */
|
|
src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
|
|
EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
|
|
else
|
|
EMIT1(0x88);
|
|
goto stx;
|
|
case BPF_STX | BPF_MEM | BPF_H:
|
|
if (is_ereg(dst_reg) || is_ereg(src_reg))
|
|
EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
|
|
else
|
|
EMIT2(0x66, 0x89);
|
|
goto stx;
|
|
case BPF_STX | BPF_MEM | BPF_W:
|
|
if (is_ereg(dst_reg) || is_ereg(src_reg))
|
|
EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
|
|
else
|
|
EMIT1(0x89);
|
|
goto stx;
|
|
case BPF_STX | BPF_MEM | BPF_DW:
|
|
EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
|
|
stx: if (is_imm8(insn->off))
|
|
EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
|
|
else
|
|
EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
|
|
insn->off);
|
|
break;
|
|
|
|
/* LDX: dst_reg = *(u8*)(src_reg + off) */
|
|
case BPF_LDX | BPF_MEM | BPF_B:
|
|
/* emit 'movzx rax, byte ptr [rax + off]' */
|
|
EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
|
|
goto ldx;
|
|
case BPF_LDX | BPF_MEM | BPF_H:
|
|
/* emit 'movzx rax, word ptr [rax + off]' */
|
|
EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
|
|
goto ldx;
|
|
case BPF_LDX | BPF_MEM | BPF_W:
|
|
/* emit 'mov eax, dword ptr [rax+0x14]' */
|
|
if (is_ereg(dst_reg) || is_ereg(src_reg))
|
|
EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
|
|
else
|
|
EMIT1(0x8B);
|
|
goto ldx;
|
|
case BPF_LDX | BPF_MEM | BPF_DW:
|
|
/* emit 'mov rax, qword ptr [rax+0x14]' */
|
|
EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
|
|
ldx: /* if insn->off == 0 we can save one extra byte, but
|
|
* special case of x86 r13 which always needs an offset
|
|
* is not worth the hassle
|
|
*/
|
|
if (is_imm8(insn->off))
|
|
EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off);
|
|
else
|
|
EMIT1_off32(add_2reg(0x80, src_reg, dst_reg),
|
|
insn->off);
|
|
break;
|
|
|
|
/* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */
|
|
case BPF_STX | BPF_XADD | BPF_W:
|
|
/* emit 'lock add dword ptr [rax + off], eax' */
|
|
if (is_ereg(dst_reg) || is_ereg(src_reg))
|
|
EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01);
|
|
else
|
|
EMIT2(0xF0, 0x01);
|
|
goto xadd;
|
|
case BPF_STX | BPF_XADD | BPF_DW:
|
|
EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01);
|
|
xadd: if (is_imm8(insn->off))
|
|
EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
|
|
else
|
|
EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
|
|
insn->off);
|
|
break;
|
|
|
|
/* call */
|
|
case BPF_JMP | BPF_CALL:
|
|
func = (u8 *) __bpf_call_base + imm32;
|
|
jmp_offset = func - (image + addrs[i]);
|
|
if (seen_ld_abs) {
|
|
reload_skb_data = bpf_helper_changes_pkt_data(func);
|
|
if (reload_skb_data) {
|
|
EMIT1(0x57); /* push %rdi */
|
|
jmp_offset += 22; /* pop, mov, sub, mov */
|
|
} else {
|
|
EMIT2(0x41, 0x52); /* push %r10 */
|
|
EMIT2(0x41, 0x51); /* push %r9 */
|
|
/* need to adjust jmp offset, since
|
|
* pop %r9, pop %r10 take 4 bytes after call insn
|
|
*/
|
|
jmp_offset += 4;
|
|
}
|
|
}
|
|
if (!imm32 || !is_simm32(jmp_offset)) {
|
|
pr_err("unsupported bpf func %d addr %p image %p\n",
|
|
imm32, func, image);
|
|
return -EINVAL;
|
|
}
|
|
EMIT1_off32(0xE8, jmp_offset);
|
|
if (seen_ld_abs) {
|
|
if (reload_skb_data) {
|
|
EMIT1(0x5F); /* pop %rdi */
|
|
emit_load_skb_data_hlen(&prog);
|
|
} else {
|
|
EMIT2(0x41, 0x59); /* pop %r9 */
|
|
EMIT2(0x41, 0x5A); /* pop %r10 */
|
|
}
|
|
}
|
|
break;
|
|
|
|
case BPF_JMP | BPF_TAIL_CALL:
|
|
emit_bpf_tail_call(&prog);
|
|
break;
|
|
|
|
/* cond jump */
|
|
case BPF_JMP | BPF_JEQ | BPF_X:
|
|
case BPF_JMP | BPF_JNE | BPF_X:
|
|
case BPF_JMP | BPF_JGT | BPF_X:
|
|
case BPF_JMP | BPF_JLT | BPF_X:
|
|
case BPF_JMP | BPF_JGE | BPF_X:
|
|
case BPF_JMP | BPF_JLE | BPF_X:
|
|
case BPF_JMP | BPF_JSGT | BPF_X:
|
|
case BPF_JMP | BPF_JSLT | BPF_X:
|
|
case BPF_JMP | BPF_JSGE | BPF_X:
|
|
case BPF_JMP | BPF_JSLE | BPF_X:
|
|
/* cmp dst_reg, src_reg */
|
|
EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x39,
|
|
add_2reg(0xC0, dst_reg, src_reg));
|
|
goto emit_cond_jmp;
|
|
|
|
case BPF_JMP | BPF_JSET | BPF_X:
|
|
/* test dst_reg, src_reg */
|
|
EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x85,
|
|
add_2reg(0xC0, dst_reg, src_reg));
|
|
goto emit_cond_jmp;
|
|
|
|
case BPF_JMP | BPF_JSET | BPF_K:
|
|
/* test dst_reg, imm32 */
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
|
|
goto emit_cond_jmp;
|
|
|
|
case BPF_JMP | BPF_JEQ | BPF_K:
|
|
case BPF_JMP | BPF_JNE | BPF_K:
|
|
case BPF_JMP | BPF_JGT | BPF_K:
|
|
case BPF_JMP | BPF_JLT | BPF_K:
|
|
case BPF_JMP | BPF_JGE | BPF_K:
|
|
case BPF_JMP | BPF_JLE | BPF_K:
|
|
case BPF_JMP | BPF_JSGT | BPF_K:
|
|
case BPF_JMP | BPF_JSLT | BPF_K:
|
|
case BPF_JMP | BPF_JSGE | BPF_K:
|
|
case BPF_JMP | BPF_JSLE | BPF_K:
|
|
/* cmp dst_reg, imm8/32 */
|
|
EMIT1(add_1mod(0x48, dst_reg));
|
|
|
|
if (is_imm8(imm32))
|
|
EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
|
|
else
|
|
EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);
|
|
|
|
emit_cond_jmp: /* convert BPF opcode to x86 */
|
|
switch (BPF_OP(insn->code)) {
|
|
case BPF_JEQ:
|
|
jmp_cond = X86_JE;
|
|
break;
|
|
case BPF_JSET:
|
|
case BPF_JNE:
|
|
jmp_cond = X86_JNE;
|
|
break;
|
|
case BPF_JGT:
|
|
/* GT is unsigned '>', JA in x86 */
|
|
jmp_cond = X86_JA;
|
|
break;
|
|
case BPF_JLT:
|
|
/* LT is unsigned '<', JB in x86 */
|
|
jmp_cond = X86_JB;
|
|
break;
|
|
case BPF_JGE:
|
|
/* GE is unsigned '>=', JAE in x86 */
|
|
jmp_cond = X86_JAE;
|
|
break;
|
|
case BPF_JLE:
|
|
/* LE is unsigned '<=', JBE in x86 */
|
|
jmp_cond = X86_JBE;
|
|
break;
|
|
case BPF_JSGT:
|
|
/* signed '>', GT in x86 */
|
|
jmp_cond = X86_JG;
|
|
break;
|
|
case BPF_JSLT:
|
|
/* signed '<', LT in x86 */
|
|
jmp_cond = X86_JL;
|
|
break;
|
|
case BPF_JSGE:
|
|
/* signed '>=', GE in x86 */
|
|
jmp_cond = X86_JGE;
|
|
break;
|
|
case BPF_JSLE:
|
|
/* signed '<=', LE in x86 */
|
|
jmp_cond = X86_JLE;
|
|
break;
|
|
default: /* to silence gcc warning */
|
|
return -EFAULT;
|
|
}
|
|
jmp_offset = addrs[i + insn->off] - addrs[i];
|
|
if (is_imm8(jmp_offset)) {
|
|
EMIT2(jmp_cond, jmp_offset);
|
|
} else if (is_simm32(jmp_offset)) {
|
|
EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
|
|
} else {
|
|
pr_err("cond_jmp gen bug %llx\n", jmp_offset);
|
|
return -EFAULT;
|
|
}
|
|
|
|
break;
|
|
|
|
case BPF_JMP | BPF_JA:
|
|
jmp_offset = addrs[i + insn->off] - addrs[i];
|
|
if (!jmp_offset)
|
|
/* optimize out nop jumps */
|
|
break;
|
|
emit_jmp:
|
|
if (is_imm8(jmp_offset)) {
|
|
EMIT2(0xEB, jmp_offset);
|
|
} else if (is_simm32(jmp_offset)) {
|
|
EMIT1_off32(0xE9, jmp_offset);
|
|
} else {
|
|
pr_err("jmp gen bug %llx\n", jmp_offset);
|
|
return -EFAULT;
|
|
}
|
|
break;
|
|
|
|
case BPF_LD | BPF_IND | BPF_W:
|
|
func = sk_load_word;
|
|
goto common_load;
|
|
case BPF_LD | BPF_ABS | BPF_W:
|
|
func = CHOOSE_LOAD_FUNC(imm32, sk_load_word);
|
|
common_load:
|
|
ctx->seen_ld_abs = seen_ld_abs = true;
|
|
jmp_offset = func - (image + addrs[i]);
|
|
if (!func || !is_simm32(jmp_offset)) {
|
|
pr_err("unsupported bpf func %d addr %p image %p\n",
|
|
imm32, func, image);
|
|
return -EINVAL;
|
|
}
|
|
if (BPF_MODE(insn->code) == BPF_ABS) {
|
|
/* mov %esi, imm32 */
|
|
EMIT1_off32(0xBE, imm32);
|
|
} else {
|
|
/* mov %rsi, src_reg */
|
|
EMIT_mov(BPF_REG_2, src_reg);
|
|
if (imm32) {
|
|
if (is_imm8(imm32))
|
|
/* add %esi, imm8 */
|
|
EMIT3(0x83, 0xC6, imm32);
|
|
else
|
|
/* add %esi, imm32 */
|
|
EMIT2_off32(0x81, 0xC6, imm32);
|
|
}
|
|
}
|
|
/* skb pointer is in R6 (%rbx), it will be copied into
|
|
* %rdi if skb_copy_bits() call is necessary.
|
|
* sk_load_* helpers also use %r10 and %r9d.
|
|
* See bpf_jit.S
|
|
*/
|
|
if (seen_ax_reg)
|
|
/* r10 = skb->data, mov %r10, off32(%rbx) */
|
|
EMIT3_off32(0x4c, 0x8b, 0x93,
|
|
offsetof(struct sk_buff, data));
|
|
EMIT1_off32(0xE8, jmp_offset); /* call */
|
|
break;
|
|
|
|
case BPF_LD | BPF_IND | BPF_H:
|
|
func = sk_load_half;
|
|
goto common_load;
|
|
case BPF_LD | BPF_ABS | BPF_H:
|
|
func = CHOOSE_LOAD_FUNC(imm32, sk_load_half);
|
|
goto common_load;
|
|
case BPF_LD | BPF_IND | BPF_B:
|
|
func = sk_load_byte;
|
|
goto common_load;
|
|
case BPF_LD | BPF_ABS | BPF_B:
|
|
func = CHOOSE_LOAD_FUNC(imm32, sk_load_byte);
|
|
goto common_load;
|
|
|
|
case BPF_JMP | BPF_EXIT:
|
|
if (seen_exit) {
|
|
jmp_offset = ctx->cleanup_addr - addrs[i];
|
|
goto emit_jmp;
|
|
}
|
|
seen_exit = true;
|
|
/* update cleanup_addr */
|
|
ctx->cleanup_addr = proglen;
|
|
/* mov rbx, qword ptr [rbp+0] */
|
|
EMIT4(0x48, 0x8B, 0x5D, 0);
|
|
/* mov r13, qword ptr [rbp+8] */
|
|
EMIT4(0x4C, 0x8B, 0x6D, 8);
|
|
/* mov r14, qword ptr [rbp+16] */
|
|
EMIT4(0x4C, 0x8B, 0x75, 16);
|
|
/* mov r15, qword ptr [rbp+24] */
|
|
EMIT4(0x4C, 0x8B, 0x7D, 24);
|
|
|
|
/* add rbp, AUX_STACK_SPACE */
|
|
EMIT4(0x48, 0x83, 0xC5, AUX_STACK_SPACE);
|
|
EMIT1(0xC9); /* leave */
|
|
EMIT1(0xC3); /* ret */
|
|
break;
|
|
|
|
default:
|
|
/* By design x64 JIT should support all BPF instructions
|
|
* This error will be seen if new instruction was added
|
|
* to interpreter, but not to JIT
|
|
* or if there is junk in bpf_prog
|
|
*/
|
|
pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
|
|
return -EINVAL;
|
|
}
|
|
|
|
ilen = prog - temp;
|
|
if (ilen > BPF_MAX_INSN_SIZE) {
|
|
pr_err("bpf_jit: fatal insn size error\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (image) {
|
|
if (unlikely(proglen + ilen > oldproglen)) {
|
|
pr_err("bpf_jit: fatal error\n");
|
|
return -EFAULT;
|
|
}
|
|
memcpy(image + proglen, temp, ilen);
|
|
}
|
|
proglen += ilen;
|
|
addrs[i] = proglen;
|
|
prog = temp;
|
|
}
|
|
return proglen;
|
|
}
|
|
|
|
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
|
|
{
|
|
struct bpf_binary_header *header = NULL;
|
|
struct bpf_prog *tmp, *orig_prog = prog;
|
|
int proglen, oldproglen = 0;
|
|
struct jit_context ctx = {};
|
|
bool tmp_blinded = false;
|
|
u8 *image = NULL;
|
|
int *addrs;
|
|
int pass;
|
|
int i;
|
|
|
|
if (!bpf_jit_enable)
|
|
return orig_prog;
|
|
|
|
tmp = bpf_jit_blind_constants(prog);
|
|
/* If blinding was requested and we failed during blinding,
|
|
* we must fall back to the interpreter.
|
|
*/
|
|
if (IS_ERR(tmp))
|
|
return orig_prog;
|
|
if (tmp != prog) {
|
|
tmp_blinded = true;
|
|
prog = tmp;
|
|
}
|
|
|
|
addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
|
|
if (!addrs) {
|
|
prog = orig_prog;
|
|
goto out;
|
|
}
|
|
|
|
/* 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 < prog->len; i++) {
|
|
proglen += 64;
|
|
addrs[i] = proglen;
|
|
}
|
|
ctx.cleanup_addr = proglen;
|
|
|
|
/* JITed image shrinks with every pass and the loop iterates
|
|
* until the image stops shrinking. Very large bpf programs
|
|
* may converge on the last pass. In such case do one more
|
|
* pass to emit the final image
|
|
*/
|
|
for (pass = 0; pass < 10 || image; pass++) {
|
|
proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
|
|
if (proglen <= 0) {
|
|
image = NULL;
|
|
if (header)
|
|
bpf_jit_binary_free(header);
|
|
prog = orig_prog;
|
|
goto out_addrs;
|
|
}
|
|
if (image) {
|
|
if (proglen != oldproglen) {
|
|
pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
|
|
proglen, oldproglen);
|
|
prog = orig_prog;
|
|
goto out_addrs;
|
|
}
|
|
break;
|
|
}
|
|
if (proglen == oldproglen) {
|
|
header = bpf_jit_binary_alloc(proglen, &image,
|
|
1, jit_fill_hole);
|
|
if (!header) {
|
|
prog = orig_prog;
|
|
goto out_addrs;
|
|
}
|
|
}
|
|
oldproglen = proglen;
|
|
}
|
|
|
|
if (bpf_jit_enable > 1)
|
|
bpf_jit_dump(prog->len, proglen, pass + 1, image);
|
|
|
|
if (image) {
|
|
bpf_flush_icache(header, image + proglen);
|
|
bpf_jit_binary_lock_ro(header);
|
|
prog->bpf_func = (void *)image;
|
|
prog->jited = 1;
|
|
prog->jited_len = proglen;
|
|
} else {
|
|
prog = orig_prog;
|
|
}
|
|
|
|
out_addrs:
|
|
kfree(addrs);
|
|
out:
|
|
if (tmp_blinded)
|
|
bpf_jit_prog_release_other(prog, prog == orig_prog ?
|
|
tmp : orig_prog);
|
|
return prog;
|
|
}
|