// SPDX-License-Identifier: GPL-2.0-only
/*
* bpf_jit_comp.c: BPF JIT compiler
*
* Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
* Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*/
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <linux/bpf.h>
#include <asm/set_memory.h>
#include <asm/nospec-branch.h>
static 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); cnt += 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 EMIT2_off32(b1, b2, off) \
do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
#define EMIT3_off32(b1, b2, b3, off) \
do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
#define EMIT4_off32(b1, b2, b3, b4, off) \
do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
static bool is_imm8(int value)
{
return value <= 127 && value >= -128;
}
static bool is_simm32(s64 value)
{
return value == (s64)(s32)value;
}
static bool is_uimm32(u64 value)
{
return value == (u64)(u32)value;
}
/* mov dst, src */
#define EMIT_mov(DST, SRC) \
do { \
if (DST != SRC) \
EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
} while (0)
static int bpf_size_to_x86_bytes(int bpf_size)
{
if (bpf_size == BPF_W)
return 4;
else if (bpf_size == BPF_H)
return 2;
else if (bpf_size == BPF_B)
return 1;
else if (bpf_size == BPF_DW)
return 4; /* imm32 */
else
return 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 X86_JL 0x7C
#define X86_JGE 0x7D
#define X86_JLE 0x7E
#define X86_JG 0x7F
/* Pick a register outside of BPF range for JIT internal work */
#define AUX_REG (MAX_BPF_JIT_REG + 1)
/*
* The following table maps BPF registers to x86-64 registers.
*
* x86-64 register R12 is unused, since if used as base address
* register in load/store instructions, it always needs an
* extra byte of encoding and is callee saved.
*
* Also x86-64 register R9 is unused. x86-64 register R10 is
* used for blinding (if enabled).
*/
static const int reg2hex[] = {
[BPF_REG_0] = 0, /* RAX */
[BPF_REG_1] = 7, /* RDI */
[BPF_REG_2] = 6, /* RSI */
[BPF_REG_3] = 2, /* RDX */
[BPF_REG_4] = 1, /* RCX */
[BPF_REG_5] = 0, /* R8 */
[BPF_REG_6] = 3, /* RBX callee saved */
[BPF_REG_7] = 5, /* R13 callee saved */
[BPF_REG_8] = 6, /* R14 callee saved */
[BPF_REG_9] = 7, /* R15 callee saved */
[BPF_REG_FP] = 5, /* RBP readonly */
[BPF_REG_AX] = 2, /* R10 temp register */
[AUX_REG] = 3, /* R11 temp register */
};
/*
* is_ereg() == true if BPF register 'reg' maps to x86-64 r8..r15
* which need extra byte of encoding.
* rax,rcx,...,rbp have simpler encoding
*/
static bool is_ereg(u32 reg)
{
return (1 << reg) & (BIT