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 
27 const char *prog;
28 static int verbose;
29 static int x86_64;
30 
usage(void)31 static 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 
malformed_line(const char * line,int line_nr)41 static 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 
pr_warn(const char * fmt,...)48 static 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 
dump_field(FILE * fp,const char * name,const char * indent,struct insn_field * field)58 static 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 
dump_insn(FILE * fp,struct insn * insn)69 static 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 
parse_args(int argc,char ** argv)87 static 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 
main(int argc,char ** argv)110 int 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 }
174