xref: /linux/tools/perf/arch/x86/util/header.c (revision 96ac6d435100450f0565708d9b885ea2a7400e0a)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <sys/types.h>
3 #include <unistd.h>
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <string.h>
7 #include <regex.h>
8 
9 #include "../../util/header.h"
10 
11 static inline void
12 cpuid(unsigned int op, unsigned int *a, unsigned int *b, unsigned int *c,
13       unsigned int *d)
14 {
15 	__asm__ __volatile__ (".byte 0x53\n\tcpuid\n\t"
16 			      "movl %%ebx, %%esi\n\t.byte 0x5b"
17 			: "=a" (*a),
18 			"=S" (*b),
19 			"=c" (*c),
20 			"=d" (*d)
21 			: "a" (op));
22 }
23 
24 static int
25 __get_cpuid(char *buffer, size_t sz, const char *fmt)
26 {
27 	unsigned int a, b, c, d, lvl;
28 	int family = -1, model = -1, step = -1;
29 	int nb;
30 	char vendor[16];
31 
32 	cpuid(0, &lvl, &b, &c, &d);
33 	strncpy(&vendor[0], (char *)(&b), 4);
34 	strncpy(&vendor[4], (char *)(&d), 4);
35 	strncpy(&vendor[8], (char *)(&c), 4);
36 	vendor[12] = '\0';
37 
38 	if (lvl >= 1) {
39 		cpuid(1, &a, &b, &c, &d);
40 
41 		family = (a >> 8) & 0xf;  /* bits 11 - 8 */
42 		model  = (a >> 4) & 0xf;  /* Bits  7 - 4 */
43 		step   = a & 0xf;
44 
45 		/* extended family */
46 		if (family == 0xf)
47 			family += (a >> 20) & 0xff;
48 
49 		/* extended model */
50 		if (family >= 0x6)
51 			model += ((a >> 16) & 0xf) << 4;
52 	}
53 	nb = scnprintf(buffer, sz, fmt, vendor, family, model, step);
54 
55 	/* look for end marker to ensure the entire data fit */
56 	if (strchr(buffer, '$')) {
57 		buffer[nb-1] = '\0';
58 		return 0;
59 	}
60 	return -1;
61 }
62 
63 int
64 get_cpuid(char *buffer, size_t sz)
65 {
66 	return __get_cpuid(buffer, sz, "%s,%u,%u,%u$");
67 }
68 
69 char *
70 get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
71 {
72 	char *buf = malloc(128);
73 
74 	if (buf && __get_cpuid(buf, 128, "%s-%u-%X-%X$") < 0) {
75 		free(buf);
76 		return NULL;
77 	}
78 	return buf;
79 }
80 
81 /* Full CPUID format for x86 is vendor-family-model-stepping */
82 static bool is_full_cpuid(const char *id)
83 {
84 	const char *tmp = id;
85 	int count = 0;
86 
87 	while ((tmp = strchr(tmp, '-')) != NULL) {
88 		count++;
89 		tmp++;
90 	}
91 
92 	if (count == 3)
93 		return true;
94 
95 	return false;
96 }
97 
98 int strcmp_cpuid_str(const char *mapcpuid, const char *id)
99 {
100 	regex_t re;
101 	regmatch_t pmatch[1];
102 	int match;
103 	bool full_mapcpuid = is_full_cpuid(mapcpuid);
104 	bool full_cpuid = is_full_cpuid(id);
105 
106 	/*
107 	 * Full CPUID format is required to identify a platform.
108 	 * Error out if the cpuid string is incomplete.
109 	 */
110 	if (full_mapcpuid && !full_cpuid) {
111 		pr_info("Invalid CPUID %s. Full CPUID is required, "
112 			"vendor-family-model-stepping\n", id);
113 		return 1;
114 	}
115 
116 	if (regcomp(&re, mapcpuid, REG_EXTENDED) != 0) {
117 		/* Warn unable to generate match particular string. */
118 		pr_info("Invalid regular expression %s\n", mapcpuid);
119 		return 1;
120 	}
121 
122 	match = !regexec(&re, id, 1, pmatch, 0);
123 	regfree(&re);
124 	if (match) {
125 		size_t match_len = (pmatch[0].rm_eo - pmatch[0].rm_so);
126 		size_t cpuid_len;
127 
128 		/* If the full CPUID format isn't required,
129 		 * ignoring the stepping.
130 		 */
131 		if (!full_mapcpuid && full_cpuid)
132 			cpuid_len = strrchr(id, '-') - id;
133 		else
134 			cpuid_len = strlen(id);
135 
136 		/* Verify the entire string matched. */
137 		if (match_len == cpuid_len)
138 			return 0;
139 	}
140 
141 	return 1;
142 }
143