1 /* -*- mode: C; c-basic-offset: 3; -*- */
2
3 #include <setjmp.h>
4 #include <signal.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <assert.h>
9 #include <ctype.h> // isspace
10 #include <fcntl.h> // open
11 #include <unistd.h> // lseek
12 #include <sys/stat.h> // S_IRUSR
13
14 // This file determines s390x features a processor supports.
15 //
16 // We return:
17 // - 0 if the machine provides the asked-for feature and the cpu
18 // model, if specified, matches the machine
19 // - 1 the machine does not provide the asked-for feature or the
20 // cpu model, if specified, does not match the machine
21 // - 1 for an unknown cpu model in /proc/cpu_info
22 // - 2 if the asked-for feature isn't recognised (this will be the case for
23 // any feature if run on a non-s390x machine).
24 // - 3 if there was a usage error (it also prints an error message).
25 //
26 // USAGE:
27 //
28 // s390x_features <feature> [<machine-model>]
29 //
30 // The machine_model is optional and it can be something like:
31 //
32 // z9 -- Host needs to be a z9 (and nothing else)
33 // z9: -- Host needs to be a z9 or any later model
34 // :z9 -- Host needs to be a model up to and including z9
35 // z900:z9 -- Host needs to be at least a z900 and at most a z9.
36 // Any model in between is OK, too.
37
38 jmp_buf env;
39
40 #if defined(VGA_s390x)
41
handle_sigill(int signum)42 void handle_sigill(int signum)
43 {
44 longjmp(env, 1);
45 }
46
stfle(void)47 unsigned long long stfle(void)
48 {
49
50 unsigned long long ret;
51
52 signal(SIGILL, handle_sigill);
53 if (setjmp(env)) {
54 /* stfle not available: assume no facilities */
55 return 0;
56 } else {
57 asm volatile("lghi 0, 0\n"
58 ".insn s,0xb2b00000,%0\n" /* stfle */
59 : "=Q" (ret)::"0", "cc");
60 return ret;
61 }
62 }
63
64
65 /* Read /proc/cpuinfo. Look for lines like these
66
67 processor 0: version = FF, identification = 0117C9, machine = 2064
68
69 and return the machine model or NULL on error.
70 Adapted from function VG_(get_machine_model) in coregrind/m_machine.c */
71
72 typedef struct {
73 const char *cpuinfo_name;
74 const char *real_name;
75 } model_info;
76
77 /* Array needs to be sorted chronologically. Oldest to newest */
78 model_info models[] = {
79 { "2064", "z900" },
80 { "2066", "z800" },
81 { "2084", "z990" },
82 { "2086", "z890" },
83 { "2094", "z9-EC" },
84 { "2096", "z9-BC" },
85 { "2097", "z10-EC" },
86 { "2098", "z10-BC" },
87 { "2817", "z196" },
88 { "2818", "z114" },
89 { "2827", "zEC12" },
90 { "2828", "zBC12" },
91 { "2964", "z13" },
92 };
93
94
95 /* Locate a machine model by name. Name can be either the cpuinfo
96 name or the external name. */
locate_model(const char * name)97 static model_info *locate_model(const char *name)
98 {
99 model_info *p;
100
101 /* Try cpuinfo name first */
102 for (p = models; p != models + sizeof models / sizeof models[0]; ++p) {
103 if (strcmp(p->cpuinfo_name, name) == 0) return p; // found it
104 }
105
106 /* Now try external name */
107 for (p = models; p != models + sizeof models / sizeof models[0]; ++p) {
108 if (strcmp(p->real_name, name) == 0) return p; // found it
109 }
110
111 return NULL;
112 }
113
114
get_host(void)115 static model_info *get_host(void)
116 {
117 int n, fh;
118 size_t num_bytes, file_buf_size;
119 char *p, *m, *model_name, *file_buf;
120 model_info *model;
121
122 /* Slurp contents of /proc/cpuinfo into FILE_BUF */
123 fh = open("/proc/cpuinfo", O_RDONLY, S_IRUSR);
124 if (fh < 0) return NULL;
125
126 /* Determine the size of /proc/cpuinfo.
127 Work around broken-ness in /proc file system implementation.
128 fstat returns a zero size for /proc/cpuinfo although it is
129 claimed to be a regular file. */
130 num_bytes = 0;
131 file_buf_size = 1000;
132 file_buf = malloc(file_buf_size + 1);
133
134 while (42) {
135 n = read(fh, file_buf, file_buf_size);
136 if (n < 0) break;
137
138 num_bytes += n;
139 if (n < file_buf_size) break; /* reached EOF */
140 }
141
142 if (n < 0) num_bytes = 0; /* read error; ignore contents */
143
144 if (num_bytes > file_buf_size) {
145 free(file_buf);
146 lseek(fh, 0, SEEK_SET);
147 file_buf = malloc(num_bytes + 1);
148 n = read(fh, file_buf, num_bytes);
149 if (n < 0) num_bytes = 0;
150 }
151
152 file_buf[num_bytes] = '\0';
153 close(fh);
154
155 /* Parse file */
156 model = models + sizeof models / sizeof models[0];
157 for (p = file_buf; *p; ++p) {
158 /* Beginning of line */
159 if (strncmp(p, "processor", sizeof "processor" - 1 ) != 0) continue;
160
161 m = strstr(p, "machine");
162 if (m == NULL) continue;
163
164 p = m + sizeof "machine" - 1;
165 while (isspace(*p) || *p == '=') {
166 if (*p == '\n') goto next_line;
167 ++p;
168 }
169
170 model_name = p;
171 for (n = 0; n < sizeof models / sizeof models[0]; ++n) {
172 model_info *mm = models + n;
173 size_t len = strlen(mm->cpuinfo_name);
174 if (strncmp(mm->cpuinfo_name, model_name, len) == 0 &&
175 isspace(model_name[len])) {
176 /* In case there are different CPUs in this cluster return the
177 one with the dewest capabilities ("oldest" model). */
178 if (mm < model) model = mm;
179 p = model_name + len;
180 break;
181 }
182 }
183 /* Skip until end-of-line */
184 while (*p != '\n')
185 ++p;
186 next_line: ;
187 }
188
189 free(file_buf);
190
191 if (model == models + sizeof models / sizeof models[0]) return NULL;
192
193 return model;
194 }
195
196
197 /* Convenience macro that maps the facility bit number as given in the
198 Principles of Ops "facility indications" section to a bit mask */
199 #define FAC_BIT(x) (1ULL << (63 - (x)))
200
go(char * feature,char * cpu)201 static int go(char *feature, char *cpu)
202 {
203 unsigned long long facilities;
204 unsigned long long match;
205 model_info *host, *from, *to, *p;
206 char *colon;
207
208 facilities = stfle();
209
210 if (strcmp(feature, "s390x-zarch") == 0 ) {
211 match = (facilities & FAC_BIT(1)) && (facilities & FAC_BIT(2));
212 } else if (strcmp(feature, "s390x-n3") == 0 ) {
213 match = facilities & FAC_BIT(0);
214 } else if (strcmp(feature, "s390x-stfle") == 0 ) {
215 match = facilities & FAC_BIT(7);
216 } else if (strcmp(feature, "s390x-ldisp") == 0 ) {
217 match = (facilities & FAC_BIT(18)) && (facilities & FAC_BIT(19));
218 } else if (strcmp(feature, "s390x-eimm") == 0 ) {
219 match = facilities & FAC_BIT(21);
220 } else if (strcmp(feature, "s390x-stckf") == 0 ) {
221 match = facilities & FAC_BIT(25);
222 } else if (strcmp(feature, "s390x-genins") == 0 ) {
223 match = facilities & FAC_BIT(34);
224 } else if (strcmp(feature, "s390x-exrl") == 0 ) {
225 match = facilities & FAC_BIT(35);
226 } else if (strcmp(feature, "s390x-etf3") == 0 ) {
227 match = facilities & FAC_BIT(30);
228 } else if (strcmp(feature, "s390x-fpext") == 0 ) {
229 match = facilities & FAC_BIT(37);
230 } else if (strcmp(feature, "s390x-dfp") == 0 ) {
231 match = facilities & FAC_BIT(42);
232 } else if (strcmp(feature, "s390x-pfpo") == 0 ) {
233 match = facilities & FAC_BIT(44);
234 } else {
235 return 2; // Unrecognised feature.
236 }
237
238 if (match == 0) return 1; // facility not provided
239
240 /* Host provides facility. If no CPU was specified, we're done. */
241 if (cpu == NULL) return 0;
242
243 host = get_host();
244 if (host == NULL) return 1; // unknown model
245
246 // printf("host = %s (%s)\n", host->cpuinfo_name, host->real_name);
247
248 /* Determine interval of models in which to search for HOST. */
249 from = to = NULL;
250 colon = strchr(cpu, ':');
251
252 if (colon == NULL) {
253 // match exact
254 from = to = locate_model(cpu);
255 } else if (colon == cpu) {
256 // :NAME match machines up to and including CPU
257 from = models;
258 to = locate_model(cpu + 1);
259 } else if (colon[1] == '\0') {
260 // NAME: match machines beginning with CPU or later
261 *colon = '\0';
262 from = locate_model(cpu);
263 to = models + sizeof models / sizeof models[0] - 1;
264 *colon = ':';
265 } else {
266 // NAME:NAME match machines in interval
267 *colon = '\0';
268 from = locate_model(cpu);
269 to = locate_model(colon + 1);
270 *colon = ':';
271 }
272
273 if (from == NULL || to == NULL || from > to) {
274 fprintf(stderr, "invalid cpu specification '%s'\n", cpu);
275 return 3;
276 }
277
278 #if 0
279 printf("from %s (%s) to %s (%s)\n", from->cpuinfo_name, from->real_name,
280 to->cpuinfo_name, to->real_name);
281 #endif
282
283 /* Search for HOST. */
284 for (p = from; p <= to; ++p) {
285 if (p == host) return 0;
286 }
287
288 return 1; // host does not match CPU specification
289 }
290
291 #else
292
go(char * feature,char * cpu)293 static int go(char *feature, char *cpu)
294 {
295 return 2; // Feature not recognised (non-s390x machine!)
296 }
297
298 #endif
299
300
301 //---------------------------------------------------------------------------
302 // main
303 //---------------------------------------------------------------------------
main(int argc,char ** argv)304 int main(int argc, char **argv)
305 {
306 int rc, inverted = 0;
307
308 if (argc < 2 || argc > 3) {
309 fprintf( stderr, "usage: s390x_features <feature> [<machine-model>]\n" );
310 exit(3); // Usage error.
311 }
312
313 if (argv[1][0] == '!') {
314 assert(argv[2] == NULL); // not allowed
315 inverted = 1;
316 ++argv[1];
317 }
318
319 rc = go(argv[1], argv[2]);
320
321 if (inverted) {
322 switch (rc) {
323 case 0: rc = 1; break;
324 case 1: rc = 0; break;
325 case 2: rc = 2; break;
326 }
327 }
328
329 // printf("rc = %d\n", rc);
330
331 return rc;
332 }
333