insn_decoder_test.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *
  4 * Copyright (C) IBM Corporation, 2009
  5 */
  6
  7#include <stdlib.h>
  8#include <stdio.h>
  9#include <string.h>
 10#include <assert.h>
 11#include <unistd.h>
 12#include <stdarg.h>
 13#include <linux/kallsyms.h>
 14
 15#include <asm/insn.h>
 16#include <inat.c>
 17#include <insn.c>
 18
 19/*
 20 * Test of instruction analysis in general and insn_get_length() in
 21 * particular.  See if insn_get_length() and the disassembler agree
 22 * on the length of each instruction in an elf disassembly.
 23 *
 24 * Usage: objdump -d a.out | awk -f objdump_reformat.awk | ./insn_decoder_test
 25 */
 26
 27const char *prog;
 28static int verbose;
 29static int x86_64;
 30
 31static void usage(void)
 32{
 33	fprintf(stderr, "Usage: objdump -d a.out | awk -f objdump_reformat.awk"
 34		" | %s [-y|-n] [-v]\n", prog);
 35	fprintf(stderr, "\t-y	64bit mode\n");
 36	fprintf(stderr, "\t-n	32bit mode\n");
 37	fprintf(stderr, "\t-v	verbose mode\n");
 38	exit(1);
 39}
 40
 41static void malformed_line(const char *line, int line_nr)
 42{
 43	fprintf(stderr, "%s: error: malformed line %d:\n%s",
 44		prog, line_nr, line);
 45	exit(3);
 46}
 47
 48static void pr_warn(const char *fmt, ...)
 49{
 50	va_list ap;
 51
 52	fprintf(stderr, "%s: warning: ", prog);
 53	va_start(ap, fmt);
 54	vfprintf(stderr, fmt, ap);
 55	va_end(ap);
 56}
 57
 58static void dump_field(FILE *fp, const char *name, const char *indent,
 59		       struct insn_field *field)
 60{
 61	fprintf(fp, "%s.%s = {\n", indent, name);
 62	fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
 63		indent, field->value, field->bytes[0], field->bytes[1],
 64		field->bytes[2], field->bytes[3]);
 65	fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
 66		field->got, field->nbytes);
 67}
 68
 69static void dump_insn(FILE *fp, struct insn *insn)
 70{
 71	fprintf(fp, "Instruction = {\n");
 72	dump_field(fp, "prefixes", "\t",	&insn->prefixes);
 73	dump_field(fp, "rex_prefix", "\t",	&insn->rex_prefix);
 74	dump_field(fp, "vex_prefix", "\t",	&insn->vex_prefix);
 75	dump_field(fp, "opcode", "\t",		&insn->opcode);
 76	dump_field(fp, "modrm", "\t",		&insn->modrm);
 77	dump_field(fp, "sib", "\t",		&insn->sib);
 78	dump_field(fp, "displacement", "\t",	&insn->displacement);
 79	dump_field(fp, "immediate1", "\t",	&insn->immediate1);
 80	dump_field(fp, "immediate2", "\t",	&insn->immediate2);
 81	fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
 82		insn->attr, insn->opnd_bytes, insn->addr_bytes);
 83	fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
 84		insn->length, insn->x86_64, insn->kaddr);
 85}
 86
 87static void parse_args(int argc, char **argv)
 88{
 89	int c;
 90	prog = argv[0];
 91	while ((c = getopt(argc, argv, "ynv")) != -1) {
 92		switch (c) {
 93		case 'y':
 94			x86_64 = 1;
 95			break;
 96		case 'n':
 97			x86_64 = 0;
 98			break;
 99		case 'v':
100			verbose = 1;
101			break;
102		default:
103			usage();
104		}
105	}
106}
107
108#define BUFSIZE (256 + KSYM_NAME_LEN)
109
110int main(int argc, char **argv)
111{
112	char line[BUFSIZE], sym[BUFSIZE] = "<unknown>";
113	unsigned char insn_buff[16];
114	struct insn insn;
115	int insns = 0;
116	int warnings = 0;
117
118	parse_args(argc, argv);
119
120	while (fgets(line, BUFSIZE, stdin)) {
121		char copy[BUFSIZE], *s, *tab1, *tab2;
122		int nb = 0, ret;
123		unsigned int b;
124
125		if (line[0] == '<') {
126			/* Symbol line */
127			strcpy(sym, line);
128			continue;
129		}
130
131		insns++;
132		memset(insn_buff, 0, 16);
133		strcpy(copy, line);
134		tab1 = strchr(copy, '\t');
135		if (!tab1)
136			malformed_line(line, insns);
137		s = tab1 + 1;
138		s += strspn(s, " ");
139		tab2 = strchr(s, '\t');
140		if (!tab2)
141			malformed_line(line, insns);
142		*tab2 = '\0';	/* Characters beyond tab2 aren't examined */
143		while (s < tab2) {
144			if (sscanf(s, "%x", &b) == 1) {
145				insn_buff[nb++] = (unsigned char) b;
146				s += 3;
147			} else
148				break;
149		}
150
151		/* Decode an instruction */
152		ret = insn_decode(&insn, insn_buff, sizeof(insn_buff),
153				  x86_64 ? INSN_MODE_64 : INSN_MODE_32);
154
155		if (ret < 0 || insn.length != nb) {
156			warnings++;
157			pr_warn("Found an x86 instruction decoder bug, "
158				"please report this.\n", sym);
159			pr_warn("%s", line);
160			pr_warn("objdump says %d bytes, but insn_get_length() "
161				"says %d\n", nb, insn.length);
162			if (verbose)
163				dump_insn(stderr, &insn);
164		}
165	}
166	if (warnings)
167		pr_warn("Decoded and checked %d instructions with %d "
168			"failures\n", insns, warnings);
169	else
170		fprintf(stdout, "  %s: success: Decoded and checked %d"
171			" instructions\n", prog, insns);
172	return 0;
173}