linux-stable/arch/x86/include/asm/inat.h
Ricardo Neri 32d0b95300 x86/insn-eval: Add utility functions to get segment selector
When computing a linear address and segmentation is used, we need to know
the base address of the segment involved in the computation. In most of
the cases, the segment base address will be zero as in USER_DS/USER32_DS.
However, it may be possible that a user space program defines its own
segments via a local descriptor table. In such a case, the segment base
address may not be zero. Thus, the segment base address is needed to
calculate correctly the linear address.

If running in protected mode, the segment selector to be used when
computing a linear address is determined by either any of segment override
prefixes in the instruction or inferred from the registers involved in the
computation of the effective address; in that order. Also, there are cases
when the segment override prefixes shall be ignored (i.e., code segments
are always selected by the CS segment register; string instructions always
use the ES segment register when using rDI register as operand). In long
mode, segment registers are ignored, except for FS and GS. In these two
cases, base addresses are obtained from the respective MSRs.

For clarity, this process can be split into four steps (and an equal
number of functions): determine if segment prefixes overrides can be used;
parse the segment override prefixes, and use them if found; if not found
or cannot be used, use the default segment registers associated with the
operand registers. Once the segment register to use has been identified,
read its value to obtain the segment selector.

The method to obtain the segment selector depends on several factors. In
32-bit builds, segment selectors are saved into a pt_regs structure
when switching to kernel mode. The same is also true for virtual-8086
mode. In 64-bit builds, segmentation is mostly ignored, except when
running a program in 32-bit legacy mode. In this case, CS and SS can be
obtained from pt_regs. DS, ES, FS and GS can be read directly from
the respective segment registers.

In order to identify the segment registers, a new set of #defines is
introduced. It also includes two special identifiers. One of them
indicates when the default segment register associated with instruction
operands shall be used. Another one indicates that the contents of the
segment register shall be ignored; this identifier is used when in long
mode.

Improvements-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: ricardo.neri@intel.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Garnier <thgarnie@google.com>
Link: https://lkml.kernel.org/r/1509135945-13762-14-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-11-01 21:50:11 +01:00

244 lines
6.6 KiB
C

#ifndef _ASM_X86_INAT_H
#define _ASM_X86_INAT_H
/*
* x86 instruction attributes
*
* Written by Masami Hiramatsu <mhiramat@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <asm/inat_types.h>
/*
* Internal bits. Don't use bitmasks directly, because these bits are
* unstable. You should use checking functions.
*/
#define INAT_OPCODE_TABLE_SIZE 256
#define INAT_GROUP_TABLE_SIZE 8
/* Legacy last prefixes */
#define INAT_PFX_OPNDSZ 1 /* 0x66 */ /* LPFX1 */
#define INAT_PFX_REPE 2 /* 0xF3 */ /* LPFX2 */
#define INAT_PFX_REPNE 3 /* 0xF2 */ /* LPFX3 */
/* Other Legacy prefixes */
#define INAT_PFX_LOCK 4 /* 0xF0 */
#define INAT_PFX_CS 5 /* 0x2E */
#define INAT_PFX_DS 6 /* 0x3E */
#define INAT_PFX_ES 7 /* 0x26 */
#define INAT_PFX_FS 8 /* 0x64 */
#define INAT_PFX_GS 9 /* 0x65 */
#define INAT_PFX_SS 10 /* 0x36 */
#define INAT_PFX_ADDRSZ 11 /* 0x67 */
/* x86-64 REX prefix */
#define INAT_PFX_REX 12 /* 0x4X */
/* AVX VEX prefixes */
#define INAT_PFX_VEX2 13 /* 2-bytes VEX prefix */
#define INAT_PFX_VEX3 14 /* 3-bytes VEX prefix */
#define INAT_PFX_EVEX 15 /* EVEX prefix */
#define INAT_LSTPFX_MAX 3
#define INAT_LGCPFX_MAX 11
/* Immediate size */
#define INAT_IMM_BYTE 1
#define INAT_IMM_WORD 2
#define INAT_IMM_DWORD 3
#define INAT_IMM_QWORD 4
#define INAT_IMM_PTR 5
#define INAT_IMM_VWORD32 6
#define INAT_IMM_VWORD 7
/* Legacy prefix */
#define INAT_PFX_OFFS 0
#define INAT_PFX_BITS 4
#define INAT_PFX_MAX ((1 << INAT_PFX_BITS) - 1)
#define INAT_PFX_MASK (INAT_PFX_MAX << INAT_PFX_OFFS)
/* Escape opcodes */
#define INAT_ESC_OFFS (INAT_PFX_OFFS + INAT_PFX_BITS)
#define INAT_ESC_BITS 2
#define INAT_ESC_MAX ((1 << INAT_ESC_BITS) - 1)
#define INAT_ESC_MASK (INAT_ESC_MAX << INAT_ESC_OFFS)
/* Group opcodes (1-16) */
#define INAT_GRP_OFFS (INAT_ESC_OFFS + INAT_ESC_BITS)
#define INAT_GRP_BITS 5
#define INAT_GRP_MAX ((1 << INAT_GRP_BITS) - 1)
#define INAT_GRP_MASK (INAT_GRP_MAX << INAT_GRP_OFFS)
/* Immediates */
#define INAT_IMM_OFFS (INAT_GRP_OFFS + INAT_GRP_BITS)
#define INAT_IMM_BITS 3
#define INAT_IMM_MASK (((1 << INAT_IMM_BITS) - 1) << INAT_IMM_OFFS)
/* Flags */
#define INAT_FLAG_OFFS (INAT_IMM_OFFS + INAT_IMM_BITS)
#define INAT_MODRM (1 << (INAT_FLAG_OFFS))
#define INAT_FORCE64 (1 << (INAT_FLAG_OFFS + 1))
#define INAT_SCNDIMM (1 << (INAT_FLAG_OFFS + 2))
#define INAT_MOFFSET (1 << (INAT_FLAG_OFFS + 3))
#define INAT_VARIANT (1 << (INAT_FLAG_OFFS + 4))
#define INAT_VEXOK (1 << (INAT_FLAG_OFFS + 5))
#define INAT_VEXONLY (1 << (INAT_FLAG_OFFS + 6))
#define INAT_EVEXONLY (1 << (INAT_FLAG_OFFS + 7))
/* Attribute making macros for attribute tables */
#define INAT_MAKE_PREFIX(pfx) (pfx << INAT_PFX_OFFS)
#define INAT_MAKE_ESCAPE(esc) (esc << INAT_ESC_OFFS)
#define INAT_MAKE_GROUP(grp) ((grp << INAT_GRP_OFFS) | INAT_MODRM)
#define INAT_MAKE_IMM(imm) (imm << INAT_IMM_OFFS)
/* Identifiers for segment registers */
#define INAT_SEG_REG_IGNORE 0
#define INAT_SEG_REG_DEFAULT 1
#define INAT_SEG_REG_CS 2
#define INAT_SEG_REG_SS 3
#define INAT_SEG_REG_DS 4
#define INAT_SEG_REG_ES 5
#define INAT_SEG_REG_FS 6
#define INAT_SEG_REG_GS 7
/* Attribute search APIs */
extern insn_attr_t inat_get_opcode_attribute(insn_byte_t opcode);
extern int inat_get_last_prefix_id(insn_byte_t last_pfx);
extern insn_attr_t inat_get_escape_attribute(insn_byte_t opcode,
int lpfx_id,
insn_attr_t esc_attr);
extern insn_attr_t inat_get_group_attribute(insn_byte_t modrm,
int lpfx_id,
insn_attr_t esc_attr);
extern insn_attr_t inat_get_avx_attribute(insn_byte_t opcode,
insn_byte_t vex_m,
insn_byte_t vex_pp);
/* Attribute checking functions */
static inline int inat_is_legacy_prefix(insn_attr_t attr)
{
attr &= INAT_PFX_MASK;
return attr && attr <= INAT_LGCPFX_MAX;
}
static inline int inat_is_address_size_prefix(insn_attr_t attr)
{
return (attr & INAT_PFX_MASK) == INAT_PFX_ADDRSZ;
}
static inline int inat_is_operand_size_prefix(insn_attr_t attr)
{
return (attr & INAT_PFX_MASK) == INAT_PFX_OPNDSZ;
}
static inline int inat_is_rex_prefix(insn_attr_t attr)
{
return (attr & INAT_PFX_MASK) == INAT_PFX_REX;
}
static inline int inat_last_prefix_id(insn_attr_t attr)
{
if ((attr & INAT_PFX_MASK) > INAT_LSTPFX_MAX)
return 0;
else
return attr & INAT_PFX_MASK;
}
static inline int inat_is_vex_prefix(insn_attr_t attr)
{
attr &= INAT_PFX_MASK;
return attr == INAT_PFX_VEX2 || attr == INAT_PFX_VEX3 ||
attr == INAT_PFX_EVEX;
}
static inline int inat_is_evex_prefix(insn_attr_t attr)
{
return (attr & INAT_PFX_MASK) == INAT_PFX_EVEX;
}
static inline int inat_is_vex3_prefix(insn_attr_t attr)
{
return (attr & INAT_PFX_MASK) == INAT_PFX_VEX3;
}
static inline int inat_is_escape(insn_attr_t attr)
{
return attr & INAT_ESC_MASK;
}
static inline int inat_escape_id(insn_attr_t attr)
{
return (attr & INAT_ESC_MASK) >> INAT_ESC_OFFS;
}
static inline int inat_is_group(insn_attr_t attr)
{
return attr & INAT_GRP_MASK;
}
static inline int inat_group_id(insn_attr_t attr)
{
return (attr & INAT_GRP_MASK) >> INAT_GRP_OFFS;
}
static inline int inat_group_common_attribute(insn_attr_t attr)
{
return attr & ~INAT_GRP_MASK;
}
static inline int inat_has_immediate(insn_attr_t attr)
{
return attr & INAT_IMM_MASK;
}
static inline int inat_immediate_size(insn_attr_t attr)
{
return (attr & INAT_IMM_MASK) >> INAT_IMM_OFFS;
}
static inline int inat_has_modrm(insn_attr_t attr)
{
return attr & INAT_MODRM;
}
static inline int inat_is_force64(insn_attr_t attr)
{
return attr & INAT_FORCE64;
}
static inline int inat_has_second_immediate(insn_attr_t attr)
{
return attr & INAT_SCNDIMM;
}
static inline int inat_has_moffset(insn_attr_t attr)
{
return attr & INAT_MOFFSET;
}
static inline int inat_has_variant(insn_attr_t attr)
{
return attr & INAT_VARIANT;
}
static inline int inat_accept_vex(insn_attr_t attr)
{
return attr & INAT_VEXOK;
}
static inline int inat_must_vex(insn_attr_t attr)
{
return attr & (INAT_VEXONLY | INAT_EVEXONLY);
}
static inline int inat_must_evex(insn_attr_t attr)
{
return attr & INAT_EVEXONLY;
}
#endif