mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 16:38:12 +00:00
52fa82c21f
Add a helper to decode kernel instructions; there's no point in endlessly repeating those last two arguments. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210326151259.379242587@infradead.org
276 lines
7.7 KiB
C
276 lines
7.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
#ifndef _ASM_X86_INSN_H
|
|
#define _ASM_X86_INSN_H
|
|
/*
|
|
* x86 instruction analysis
|
|
*
|
|
* Copyright (C) IBM Corporation, 2009
|
|
*/
|
|
|
|
#include <asm/byteorder.h>
|
|
/* insn_attr_t is defined in inat.h */
|
|
#include <asm/inat.h> /* __ignore_sync_check__ */
|
|
|
|
#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
|
|
|
|
struct insn_field {
|
|
union {
|
|
insn_value_t value;
|
|
insn_byte_t bytes[4];
|
|
};
|
|
/* !0 if we've run insn_get_xxx() for this field */
|
|
unsigned char got;
|
|
unsigned char nbytes;
|
|
};
|
|
|
|
static inline void insn_field_set(struct insn_field *p, insn_value_t v,
|
|
unsigned char n)
|
|
{
|
|
p->value = v;
|
|
p->nbytes = n;
|
|
}
|
|
|
|
static inline void insn_set_byte(struct insn_field *p, unsigned char n,
|
|
insn_byte_t v)
|
|
{
|
|
p->bytes[n] = v;
|
|
}
|
|
|
|
#else
|
|
|
|
struct insn_field {
|
|
insn_value_t value;
|
|
union {
|
|
insn_value_t little;
|
|
insn_byte_t bytes[4];
|
|
};
|
|
/* !0 if we've run insn_get_xxx() for this field */
|
|
unsigned char got;
|
|
unsigned char nbytes;
|
|
};
|
|
|
|
static inline void insn_field_set(struct insn_field *p, insn_value_t v,
|
|
unsigned char n)
|
|
{
|
|
p->value = v;
|
|
p->little = __cpu_to_le32(v);
|
|
p->nbytes = n;
|
|
}
|
|
|
|
static inline void insn_set_byte(struct insn_field *p, unsigned char n,
|
|
insn_byte_t v)
|
|
{
|
|
p->bytes[n] = v;
|
|
p->value = __le32_to_cpu(p->little);
|
|
}
|
|
#endif
|
|
|
|
struct insn {
|
|
struct insn_field prefixes; /*
|
|
* Prefixes
|
|
* prefixes.bytes[3]: last prefix
|
|
*/
|
|
struct insn_field rex_prefix; /* REX prefix */
|
|
struct insn_field vex_prefix; /* VEX prefix */
|
|
struct insn_field opcode; /*
|
|
* opcode.bytes[0]: opcode1
|
|
* opcode.bytes[1]: opcode2
|
|
* opcode.bytes[2]: opcode3
|
|
*/
|
|
struct insn_field modrm;
|
|
struct insn_field sib;
|
|
struct insn_field displacement;
|
|
union {
|
|
struct insn_field immediate;
|
|
struct insn_field moffset1; /* for 64bit MOV */
|
|
struct insn_field immediate1; /* for 64bit imm or off16/32 */
|
|
};
|
|
union {
|
|
struct insn_field moffset2; /* for 64bit MOV */
|
|
struct insn_field immediate2; /* for 64bit imm or seg16 */
|
|
};
|
|
|
|
int emulate_prefix_size;
|
|
insn_attr_t attr;
|
|
unsigned char opnd_bytes;
|
|
unsigned char addr_bytes;
|
|
unsigned char length;
|
|
unsigned char x86_64;
|
|
|
|
const insn_byte_t *kaddr; /* kernel address of insn to analyze */
|
|
const insn_byte_t *end_kaddr; /* kernel address of last insn in buffer */
|
|
const insn_byte_t *next_byte;
|
|
};
|
|
|
|
#define MAX_INSN_SIZE 15
|
|
|
|
#define X86_MODRM_MOD(modrm) (((modrm) & 0xc0) >> 6)
|
|
#define X86_MODRM_REG(modrm) (((modrm) & 0x38) >> 3)
|
|
#define X86_MODRM_RM(modrm) ((modrm) & 0x07)
|
|
|
|
#define X86_SIB_SCALE(sib) (((sib) & 0xc0) >> 6)
|
|
#define X86_SIB_INDEX(sib) (((sib) & 0x38) >> 3)
|
|
#define X86_SIB_BASE(sib) ((sib) & 0x07)
|
|
|
|
#define X86_REX_W(rex) ((rex) & 8)
|
|
#define X86_REX_R(rex) ((rex) & 4)
|
|
#define X86_REX_X(rex) ((rex) & 2)
|
|
#define X86_REX_B(rex) ((rex) & 1)
|
|
|
|
/* VEX bit flags */
|
|
#define X86_VEX_W(vex) ((vex) & 0x80) /* VEX3 Byte2 */
|
|
#define X86_VEX_R(vex) ((vex) & 0x80) /* VEX2/3 Byte1 */
|
|
#define X86_VEX_X(vex) ((vex) & 0x40) /* VEX3 Byte1 */
|
|
#define X86_VEX_B(vex) ((vex) & 0x20) /* VEX3 Byte1 */
|
|
#define X86_VEX_L(vex) ((vex) & 0x04) /* VEX3 Byte2, VEX2 Byte1 */
|
|
/* VEX bit fields */
|
|
#define X86_EVEX_M(vex) ((vex) & 0x03) /* EVEX Byte1 */
|
|
#define X86_VEX3_M(vex) ((vex) & 0x1f) /* VEX3 Byte1 */
|
|
#define X86_VEX2_M 1 /* VEX2.M always 1 */
|
|
#define X86_VEX_V(vex) (((vex) & 0x78) >> 3) /* VEX3 Byte2, VEX2 Byte1 */
|
|
#define X86_VEX_P(vex) ((vex) & 0x03) /* VEX3 Byte2, VEX2 Byte1 */
|
|
#define X86_VEX_M_MAX 0x1f /* VEX3.M Maximum value */
|
|
|
|
extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64);
|
|
extern int insn_get_prefixes(struct insn *insn);
|
|
extern int insn_get_opcode(struct insn *insn);
|
|
extern int insn_get_modrm(struct insn *insn);
|
|
extern int insn_get_sib(struct insn *insn);
|
|
extern int insn_get_displacement(struct insn *insn);
|
|
extern int insn_get_immediate(struct insn *insn);
|
|
extern int insn_get_length(struct insn *insn);
|
|
|
|
enum insn_mode {
|
|
INSN_MODE_32,
|
|
INSN_MODE_64,
|
|
/* Mode is determined by the current kernel build. */
|
|
INSN_MODE_KERN,
|
|
INSN_NUM_MODES,
|
|
};
|
|
|
|
extern int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m);
|
|
|
|
#define insn_decode_kernel(_insn, _ptr) insn_decode((_insn), (_ptr), MAX_INSN_SIZE, INSN_MODE_KERN)
|
|
|
|
/* Attribute will be determined after getting ModRM (for opcode groups) */
|
|
static inline void insn_get_attribute(struct insn *insn)
|
|
{
|
|
insn_get_modrm(insn);
|
|
}
|
|
|
|
/* Instruction uses RIP-relative addressing */
|
|
extern int insn_rip_relative(struct insn *insn);
|
|
|
|
static inline int insn_is_avx(struct insn *insn)
|
|
{
|
|
if (!insn->prefixes.got)
|
|
insn_get_prefixes(insn);
|
|
return (insn->vex_prefix.value != 0);
|
|
}
|
|
|
|
static inline int insn_is_evex(struct insn *insn)
|
|
{
|
|
if (!insn->prefixes.got)
|
|
insn_get_prefixes(insn);
|
|
return (insn->vex_prefix.nbytes == 4);
|
|
}
|
|
|
|
static inline int insn_has_emulate_prefix(struct insn *insn)
|
|
{
|
|
return !!insn->emulate_prefix_size;
|
|
}
|
|
|
|
static inline insn_byte_t insn_vex_m_bits(struct insn *insn)
|
|
{
|
|
if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */
|
|
return X86_VEX2_M;
|
|
else if (insn->vex_prefix.nbytes == 3) /* 3 bytes VEX */
|
|
return X86_VEX3_M(insn->vex_prefix.bytes[1]);
|
|
else /* EVEX */
|
|
return X86_EVEX_M(insn->vex_prefix.bytes[1]);
|
|
}
|
|
|
|
static inline insn_byte_t insn_vex_p_bits(struct insn *insn)
|
|
{
|
|
if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */
|
|
return X86_VEX_P(insn->vex_prefix.bytes[1]);
|
|
else
|
|
return X86_VEX_P(insn->vex_prefix.bytes[2]);
|
|
}
|
|
|
|
/* Get the last prefix id from last prefix or VEX prefix */
|
|
static inline int insn_last_prefix_id(struct insn *insn)
|
|
{
|
|
if (insn_is_avx(insn))
|
|
return insn_vex_p_bits(insn); /* VEX_p is a SIMD prefix id */
|
|
|
|
if (insn->prefixes.bytes[3])
|
|
return inat_get_last_prefix_id(insn->prefixes.bytes[3]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Offset of each field from kaddr */
|
|
static inline int insn_offset_rex_prefix(struct insn *insn)
|
|
{
|
|
return insn->prefixes.nbytes;
|
|
}
|
|
static inline int insn_offset_vex_prefix(struct insn *insn)
|
|
{
|
|
return insn_offset_rex_prefix(insn) + insn->rex_prefix.nbytes;
|
|
}
|
|
static inline int insn_offset_opcode(struct insn *insn)
|
|
{
|
|
return insn_offset_vex_prefix(insn) + insn->vex_prefix.nbytes;
|
|
}
|
|
static inline int insn_offset_modrm(struct insn *insn)
|
|
{
|
|
return insn_offset_opcode(insn) + insn->opcode.nbytes;
|
|
}
|
|
static inline int insn_offset_sib(struct insn *insn)
|
|
{
|
|
return insn_offset_modrm(insn) + insn->modrm.nbytes;
|
|
}
|
|
static inline int insn_offset_displacement(struct insn *insn)
|
|
{
|
|
return insn_offset_sib(insn) + insn->sib.nbytes;
|
|
}
|
|
static inline int insn_offset_immediate(struct insn *insn)
|
|
{
|
|
return insn_offset_displacement(insn) + insn->displacement.nbytes;
|
|
}
|
|
|
|
/**
|
|
* for_each_insn_prefix() -- Iterate prefixes in the instruction
|
|
* @insn: Pointer to struct insn.
|
|
* @idx: Index storage.
|
|
* @prefix: Prefix byte.
|
|
*
|
|
* Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
|
|
* and the index is stored in @idx (note that this @idx is just for a cursor,
|
|
* do not change it.)
|
|
* Since prefixes.nbytes can be bigger than 4 if some prefixes
|
|
* are repeated, it cannot be used for looping over the prefixes.
|
|
*/
|
|
#define for_each_insn_prefix(insn, idx, prefix) \
|
|
for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++)
|
|
|
|
#define POP_SS_OPCODE 0x1f
|
|
#define MOV_SREG_OPCODE 0x8e
|
|
|
|
/*
|
|
* Intel SDM Vol.3A 6.8.3 states;
|
|
* "Any single-step trap that would be delivered following the MOV to SS
|
|
* instruction or POP to SS instruction (because EFLAGS.TF is 1) is
|
|
* suppressed."
|
|
* This function returns true if @insn is MOV SS or POP SS. On these
|
|
* instructions, single stepping is suppressed.
|
|
*/
|
|
static inline int insn_masking_exception(struct insn *insn)
|
|
{
|
|
return insn->opcode.bytes[0] == POP_SS_OPCODE ||
|
|
(insn->opcode.bytes[0] == MOV_SREG_OPCODE &&
|
|
X86_MODRM_REG(insn->modrm.bytes[0]) == 2);
|
|
}
|
|
|
|
#endif /* _ASM_X86_INSN_H */
|