linux/arch/x86/lib/insn.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * x86 instruction analysis
 *
 * Copyright (C) IBM Corporation, 2002, 2004, 2009
 */

#include <linux/kernel.h>
#ifdef __KERNEL__
#include <linux/string.h>
#else
#include <string.h>
#endif
#include <asm/inat.h> /*__ignore_sync_check__ */
#include <asm/insn.h> /* __ignore_sync_check__ */
#include <asm/unaligned.h> /* __ignore_sync_check__ */

#include <linux/errno.h>
#include <linux/kconfig.h>

#include <asm/emulate_prefix.h> /* __ignore_sync_check__ */

#define leXX_to_cpu(t, r) …

/* Verify next sizeof(t) bytes can be on the same instruction */
#define validate_next(t, insn, n) …

#define __get_next(t, insn) …

#define __peek_nbyte_next(t, insn, n) …

#define get_next(t, insn) …

#define peek_nbyte_next(t, insn, n) …

#define peek_next(t, insn) …

/**
 * insn_init() - initialize struct insn
 * @insn:	&struct insn to be initialized
 * @kaddr:	address (in kernel memory) of instruction (or copy thereof)
 * @buf_len:	length of the insn buffer at @kaddr
 * @x86_64:	!0 for 64-bit kernel or 64-bit app
 */
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64)
{ … }

static const insn_byte_t xen_prefix[] = …;
static const insn_byte_t kvm_prefix[] = …;

static int __insn_get_emulate_prefix(struct insn *insn,
				     const insn_byte_t *prefix, size_t len)
{ … }

static void insn_get_emulate_prefix(struct insn *insn)
{ … }

/**
 * insn_get_prefixes - scan x86 instruction prefix bytes
 * @insn:	&struct insn containing instruction
 *
 * Populates the @insn->prefixes bitmap, and updates @insn->next_byte
 * to point to the (first) opcode.  No effect if @insn->prefixes.got
 * is already set.
 *
 * * Returns:
 * 0:  on success
 * < 0: on error
 */
int insn_get_prefixes(struct insn *insn)
{ … }

/**
 * insn_get_opcode - collect opcode(s)
 * @insn:	&struct insn containing instruction
 *
 * Populates @insn->opcode, updates @insn->next_byte to point past the
 * opcode byte(s), and set @insn->attr (except for groups).
 * If necessary, first collects any preceding (prefix) bytes.
 * Sets @insn->opcode.value = opcode1.  No effect if @insn->opcode.got
 * is already 1.
 *
 * Returns:
 * 0:  on success
 * < 0: on error
 */
int insn_get_opcode(struct insn *insn)
{ … }

/**
 * insn_get_modrm - collect ModRM byte, if any
 * @insn:	&struct insn containing instruction
 *
 * Populates @insn->modrm and updates @insn->next_byte to point past the
 * ModRM byte, if any.  If necessary, first collects the preceding bytes
 * (prefixes and opcode(s)).  No effect if @insn->modrm.got is already 1.
 *
 * Returns:
 * 0:  on success
 * < 0: on error
 */
int insn_get_modrm(struct insn *insn)
{ … }


/**
 * insn_rip_relative() - Does instruction use RIP-relative addressing mode?
 * @insn:	&struct insn containing instruction
 *
 * If necessary, first collects the instruction up to and including the
 * ModRM byte.  No effect if @insn->x86_64 is 0.
 */
int insn_rip_relative(struct insn *insn)
{ … }

/**
 * insn_get_sib() - Get the SIB byte of instruction
 * @insn:	&struct insn containing instruction
 *
 * If necessary, first collects the instruction up to and including the
 * ModRM byte.
 *
 * Returns:
 * 0: if decoding succeeded
 * < 0: otherwise.
 */
int insn_get_sib(struct insn *insn)
{ … }


/**
 * insn_get_displacement() - Get the displacement of instruction
 * @insn:	&struct insn containing instruction
 *
 * If necessary, first collects the instruction up to and including the
 * SIB byte.
 * Displacement value is sign-expanded.
 *
 * * Returns:
 * 0: if decoding succeeded
 * < 0: otherwise.
 */
int insn_get_displacement(struct insn *insn)
{ … }

/* Decode moffset16/32/64. Return 0 if failed */
static int __get_moffset(struct insn *insn)
{ … }

/* Decode imm v32(Iz). Return 0 if failed */
static int __get_immv32(struct insn *insn)
{ … }

/* Decode imm v64(Iv/Ov), Return 0 if failed */
static int __get_immv(struct insn *insn)
{ … }

/* Decode ptr16:16/32(Ap) */
static int __get_immptr(struct insn *insn)
{ … }

/**
 * insn_get_immediate() - Get the immediate in an instruction
 * @insn:	&struct insn containing instruction
 *
 * If necessary, first collects the instruction up to and including the
 * displacement bytes.
 * Basically, most of immediates are sign-expanded. Unsigned-value can be
 * computed by bit masking with ((1 << (nbytes * 8)) - 1)
 *
 * Returns:
 * 0:  on success
 * < 0: on error
 */
int insn_get_immediate(struct insn *insn)
{ … }

/**
 * insn_get_length() - Get the length of instruction
 * @insn:	&struct insn containing instruction
 *
 * If necessary, first collects the instruction up to and including the
 * immediates bytes.
 *
 * Returns:
 *  - 0 on success
 *  - < 0 on error
*/
int insn_get_length(struct insn *insn)
{ … }

/* Ensure this instruction is decoded completely */
static inline int insn_complete(struct insn *insn)
{ … }

/**
 * insn_decode() - Decode an x86 instruction
 * @insn:	&struct insn to be initialized
 * @kaddr:	address (in kernel memory) of instruction (or copy thereof)
 * @buf_len:	length of the insn buffer at @kaddr
 * @m:		insn mode, see enum insn_mode
 *
 * Returns:
 * 0: if decoding succeeded
 * < 0: otherwise.
 */
int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m)
{ … }