x86: Instruction decoder API

Add x86 instruction decoder to arch-specific libraries. This decoder
can decode x86 instructions used in kernel into prefix, opcode, modrm,
sib, displacement and immediates. This can also show the length of
instructions.

This version introduces instruction attributes for decoding
instructions.
The instruction attribute tables are generated from the opcode map file
(x86-opcode-map.txt) by the generator script(gen-insn-attr-x86.awk).

Currently, the opcode maps are based on opcode maps in Intel(R) 64 and
IA-32 Architectures Software Developers Manual Vol.2: Appendix.A,
and consist of below two types of opcode tables.

1-byte/2-bytes/3-bytes opcodes, which has 256 elements, are
written as below;

 Table: table-name
 Referrer: escaped-name
 opcode: mnemonic|GrpXXX [operand1[,operand2...]] [(extra1)[,(extra2)...] [| 2nd-mnemonic ...]
  (or)
 opcode: escape # escaped-name
 EndTable

Group opcodes, which has 8 elements, are written as below;

 GrpTable: GrpXXX
 reg:  mnemonic [operand1[,operand2...]] [(extra1)[,(extra2)...] [| 2nd-mnemonic ...]
 EndTable

These opcode maps include a few SSE and FP opcodes (for setup), because
those opcodes are used in the kernel.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203413.31965.49709.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 143 insertions, 0 deletions

diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h
new file mode 100644
index 000000000000..12b4e3751d3f
--- /dev/null
+++ b/arch/x86/include/asm/insn.h
@@ -0,0 +1,143 @@
+#ifndef _ASM_X86_INSN_H
+#define _ASM_X86_INSN_H
+/*
+ * x86 instruction analysis
+ *
+ * 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.
+ *
+ * Copyright (C) IBM Corporation, 2009
+ */
+
+/* insn_attr_t is defined in inat.h */
+#include <asm/inat.h>
+
+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;
+};
+
+struct insn {
+        struct insn_field prefixes;     /*
+                                         * Prefixes
+                                         * prefixes.bytes[3]: last prefix
+                                         */
+        struct insn_field rex_prefix;   /* REX 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 */
+        };
+
+        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 *next_byte;
+};
+
+#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)
+
+/* The last prefix is needed for two-byte and three-byte opcodes */
+static inline insn_byte_t insn_last_prefix(struct insn *insn)
+{
+        return insn->prefixes.bytes[3];
+}
+
+extern void insn_init(struct insn *insn, const void *kaddr, int x86_64);
+extern void insn_get_prefixes(struct insn *insn);
+extern void insn_get_opcode(struct insn *insn);
+extern void insn_get_modrm(struct insn *insn);
+extern void insn_get_sib(struct insn *insn);
+extern void insn_get_displacement(struct insn *insn);
+extern void insn_get_immediate(struct insn *insn);
+extern void insn_get_length(struct insn *insn);
+
+/* 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);
+
+/* Init insn for kernel text */
+static inline void kernel_insn_init(struct insn *insn, const void *kaddr)
+{
+#ifdef CONFIG_X86_64
+        insn_init(insn, kaddr, 1);
+#else /* CONFIG_X86_32 */
+        insn_init(insn, kaddr, 0);
+#endif
+}
+
+/* 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_opcode(struct insn *insn)
+{
+        return insn_offset_rex_prefix(insn) + insn->rex_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;
+}
+
+#endif /* _ASM_X86_INSN_H */