1 // SPDX-License-Identifier: GPL-2.0
2 #include <sys/types.h>
3 #include <errno.h>
4 #include <unistd.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <regex.h>
9 
10 #include "../../../util/debug.h"
11 #include "../../../util/header.h"
12 #include "cpuid.h"
13 
get_cpuid_0(char * vendor,unsigned int * lvl)14 void get_cpuid_0(char *vendor, unsigned int *lvl)
15 {
16 	unsigned int b, c, d;
17 
18 	cpuid(0, 0, lvl, &b, &c, &d);
19 	strncpy(&vendor[0], (char *)(&b), 4);
20 	strncpy(&vendor[4], (char *)(&d), 4);
21 	strncpy(&vendor[8], (char *)(&c), 4);
22 	vendor[12] = '\0';
23 }
24 
25 static int
__get_cpuid(char * buffer,size_t sz,const char * fmt)26 __get_cpuid(char *buffer, size_t sz, const char *fmt)
27 {
28 	unsigned int a, b, c, d, lvl;
29 	int family = -1, model = -1, step = -1;
30 	int nb;
31 	char vendor[16];
32 
33 	get_cpuid_0(vendor, &lvl);
34 
35 	if (lvl >= 1) {
36 		cpuid(1, 0, &a, &b, &c, &d);
37 
38 		family = (a >> 8) & 0xf;  /* bits 11 - 8 */
39 		model  = (a >> 4) & 0xf;  /* Bits  7 - 4 */
40 		step   = a & 0xf;
41 
42 		/* extended family */
43 		if (family == 0xf)
44 			family += (a >> 20) & 0xff;
45 
46 		/* extended model */
47 		if (family >= 0x6)
48 			model += ((a >> 16) & 0xf) << 4;
49 	}
50 	nb = scnprintf(buffer, sz, fmt, vendor, family, model, step);
51 
52 	/* look for end marker to ensure the entire data fit */
53 	if (strchr(buffer, '$')) {
54 		buffer[nb-1] = '\0';
55 		return 0;
56 	}
57 	return ENOBUFS;
58 }
59 
60 int
get_cpuid(char * buffer,size_t sz)61 get_cpuid(char *buffer, size_t sz)
62 {
63 	return __get_cpuid(buffer, sz, "%s,%u,%u,%u$");
64 }
65 
66 char *
get_cpuid_str(struct perf_pmu * pmu __maybe_unused)67 get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
68 {
69 	char *buf = malloc(128);
70 
71 	if (buf && __get_cpuid(buf, 128, "%s-%u-%X-%X$") < 0) {
72 		free(buf);
73 		return NULL;
74 	}
75 	return buf;
76 }
77 
78 /* Full CPUID format for x86 is vendor-family-model-stepping */
is_full_cpuid(const char * id)79 static bool is_full_cpuid(const char *id)
80 {
81 	const char *tmp = id;
82 	int count = 0;
83 
84 	while ((tmp = strchr(tmp, '-')) != NULL) {
85 		count++;
86 		tmp++;
87 	}
88 
89 	if (count == 3)
90 		return true;
91 
92 	return false;
93 }
94 
strcmp_cpuid_str(const char * mapcpuid,const char * id)95 int strcmp_cpuid_str(const char *mapcpuid, const char *id)
96 {
97 	regex_t re;
98 	regmatch_t pmatch[1];
99 	int match;
100 	bool full_mapcpuid = is_full_cpuid(mapcpuid);
101 	bool full_cpuid = is_full_cpuid(id);
102 
103 	/*
104 	 * Full CPUID format is required to identify a platform.
105 	 * Error out if the cpuid string is incomplete.
106 	 */
107 	if (full_mapcpuid && !full_cpuid) {
108 		pr_info("Invalid CPUID %s. Full CPUID is required, "
109 			"vendor-family-model-stepping\n", id);
110 		return 1;
111 	}
112 
113 	if (regcomp(&re, mapcpuid, REG_EXTENDED) != 0) {
114 		/* Warn unable to generate match particular string. */
115 		pr_info("Invalid regular expression %s\n", mapcpuid);
116 		return 1;
117 	}
118 
119 	match = !regexec(&re, id, 1, pmatch, 0);
120 	regfree(&re);
121 	if (match) {
122 		size_t match_len = (pmatch[0].rm_eo - pmatch[0].rm_so);
123 		size_t cpuid_len;
124 
125 		/* If the full CPUID format isn't required,
126 		 * ignoring the stepping.
127 		 */
128 		if (!full_mapcpuid && full_cpuid)
129 			cpuid_len = strrchr(id, '-') - id;
130 		else
131 			cpuid_len = strlen(id);
132 
133 		/* Verify the entire string matched. */
134 		if (match_len == cpuid_len)
135 			return 0;
136 	}
137 
138 	return 1;
139 }
140