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08e2be29 MW |
1 | /* -*-c-*- |
2 | * | |
3 | * CPU-specific dispatch | |
4 | * | |
5 | * (c) 2015 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
16 | * | |
17 | * Catacomb is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU Library General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU Library General Public | |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
28 | /*----- Header files ------------------------------------------------------*/ | |
29 | ||
30 | #include "config.h" | |
31 | ||
32 | #include <ctype.h> | |
fac645f7 MW |
33 | #include <stdarg.h> |
34 | #include <stdio.h> | |
08e2be29 MW |
35 | #include <stdlib.h> |
36 | #include <string.h> | |
37 | ||
38 | #include <mLib/macros.h> | |
39 | ||
40 | #include "dispatch.h" | |
41 | ||
d26ad211 | 42 | /*----- Intel x86/AMD64 feature probing -----------------------------------*/ |
08e2be29 | 43 | |
0f23f75f | 44 | #if CPUFAM_X86 || CPUFAM_AMD64 |
08e2be29 | 45 | |
7680f863 MW |
46 | # define EFLAGS_ID (1u << 21) |
47 | # define CPUID1D_SSE2 (1u << 26) | |
48 | # define CPUID1D_FXSR (1u << 24) | |
9e6a4409 MW |
49 | # define CPUID1C_PCLMUL (1u << 1) |
50 | # define CPUID1C_SSSE3 (1u << 9) | |
7680f863 | 51 | # define CPUID1C_AESNI (1u << 25) |
b9b279b4 | 52 | # define CPUID1C_AVX (1u << 28) |
d25653be | 53 | # define CPUID1C_RDRAND (1u << 30) |
08e2be29 MW |
54 | |
55 | struct cpuid { unsigned a, b, c, d; }; | |
56 | ||
57 | /* --- @cpuid@ --- * | |
58 | * | |
59 | * Arguments: @struct cpuid *cc@ = where to write the result | |
60 | * @unsigned a, c@ = EAX and ECX registers to set | |
61 | * | |
62 | * Returns: --- | |
63 | * | |
64 | * Use: Minimal C wrapper around the x86 `CPUID' instruction. Checks | |
65 | * that the instruction is actually available before invoking | |
66 | * it; fills the output structure with zero if it's not going to | |
67 | * work. | |
68 | */ | |
69 | ||
70 | #ifdef __GNUC__ | |
0f23f75f | 71 | # if CPUFAM_X86 |
08e2be29 MW |
72 | static __inline__ unsigned getflags(void) |
73 | { unsigned f; __asm__ ("pushf; popl %0" : "=g" (f)); return (f); } | |
74 | static __inline__ unsigned setflags(unsigned f) | |
75 | { | |
76 | unsigned ff; | |
77 | __asm__ ("pushf; pushl %1; popf; pushf; popl %0; popf" | |
25eccdf7 MW |
78 | : "=r" (ff) |
79 | : "r" (f)); | |
08e2be29 MW |
80 | return (ff); |
81 | } | |
0f23f75f MW |
82 | # else |
83 | static __inline__ unsigned long getflags(void) | |
84 | { unsigned long f; __asm__ ("pushf; popq %0" : "=g" (f)); return (f); } | |
85 | static __inline__ unsigned long long setflags(unsigned long f) | |
86 | { | |
87 | unsigned long ff; | |
88 | __asm__ ("pushf; pushq %1; popf; pushf; popq %0; popf" | |
25eccdf7 MW |
89 | : "=r" (ff) |
90 | : "r" (f)); | |
0f23f75f MW |
91 | return (ff); |
92 | } | |
93 | # endif | |
08e2be29 MW |
94 | #endif |
95 | ||
96 | static void cpuid(struct cpuid *cc, unsigned a, unsigned c) | |
97 | { | |
98 | #ifdef __GNUC__ | |
99 | unsigned f; | |
100 | #endif | |
101 | ||
102 | cc->a = cc->b = cc->c = cc->d = 0; | |
103 | ||
104 | #ifdef __GNUC__ | |
105 | /* Stupid dance to detect whether the CPUID instruction is available. */ | |
106 | f = getflags(); | |
fac645f7 MW |
107 | if (!(setflags(f | EFLAGS_ID) & EFLAGS_ID) || |
108 | setflags(f & ~EFLAGS_ID) & EFLAGS_ID) { | |
109 | dispatch_debug("CPUID instruction not available"); | |
110 | return; | |
111 | } | |
08e2be29 MW |
112 | setflags(f); |
113 | ||
114 | /* Alas, EBX is magical in PIC code, so abuse ESI instead. This isn't | |
115 | * pretty, but it works. | |
116 | */ | |
0f23f75f | 117 | # if CPUFAM_X86 |
08e2be29 MW |
118 | __asm__ ("pushl %%ebx; cpuid; movl %%ebx, %%esi; popl %%ebx" |
119 | : "=a" (cc->a), "=S" (cc->b), "=c" (cc->c), "=d" (cc->d) | |
120 | : "a" (a) , "c" (c)); | |
0f23f75f MW |
121 | # elif CPUFAM_AMD64 |
122 | __asm__ ("pushq %%rbx; cpuid; movl %%ebx, %%esi; popq %%rbx" | |
123 | : "=a" (cc->a), "=S" (cc->b), "=c" (cc->c), "=d" (cc->d) | |
124 | : "a" (a) , "c" (c)); | |
125 | # else | |
126 | # error "I'm confused." | |
127 | # endif | |
128 | dispatch_debug("CPUID(%08x, %08x) -> %08x, %08x, %08x, %08x", | |
129 | a, c, cc->a, cc->b, cc->c, cc->d); | |
fac645f7 MW |
130 | #else |
131 | dispatch_debug("GNU inline assembler not available; can't CPUID"); | |
08e2be29 MW |
132 | #endif |
133 | } | |
134 | ||
135 | static unsigned cpuid_maxleaf(void) | |
136 | { struct cpuid c; cpuid(&c, 0, 0); return (c.a); } | |
137 | ||
11b17977 MW |
138 | /* --- @cpuid_features_p@ --- * |
139 | * | |
140 | * Arguments: @unsigned dbits@ = bits to check in EDX | |
141 | * @unsigned cbits@ = bits to check in ECX | |
142 | * | |
143 | * Returns: Nonzero if all the requested bits are set in the CPUID result | |
144 | * on leaf 1. | |
145 | */ | |
146 | ||
08e2be29 MW |
147 | static int cpuid_features_p(unsigned dbits, unsigned cbits) |
148 | { | |
149 | struct cpuid c; | |
150 | if (cpuid_maxleaf() < 1) return (0); | |
151 | cpuid(&c, 1, 0); | |
152 | return ((c.d & dbits) == dbits && (c.c & cbits) == cbits); | |
153 | } | |
154 | ||
11b17977 MW |
155 | /* --- @xmm_registers_available_p@ --- * |
156 | * | |
157 | * Arguments: --- | |
158 | * | |
159 | * Returns: Nonzero if the operating system has made the XMM registers | |
160 | * available for use. | |
161 | */ | |
162 | ||
acbe16df MW |
163 | static int xmm_registers_available_p(void) |
164 | { | |
165 | #ifdef __GNUC__ | |
166 | unsigned f; | |
167 | /* This hack is by Agner Fog. Use FXSAVE/FXRSTOR to figure out whether the | |
168 | * XMM registers are actually alive. | |
169 | */ | |
170 | if (!cpuid_features_p(CPUID1D_FXSR, 0)) return (0); | |
0f23f75f | 171 | # if CPUFAM_X86 |
acbe16df MW |
172 | __asm__ ("movl %%esp, %%edx; subl $512, %%esp; andl $~15, %%esp\n" |
173 | "fxsave (%%esp)\n" | |
174 | "movl 160(%%esp), %%eax; xorl $0xaaaa5555, 160(%%esp)\n" | |
175 | "fxrstor (%%esp); fxsave (%%esp)\n" | |
176 | "movl 160(%%esp), %%ecx; movl %%eax, 160(%%esp)\n" | |
177 | "fxrstor (%%esp); movl %%edx, %%esp\n" | |
178 | "xorl %%ecx, %%eax" | |
179 | : "=a" (f) | |
180 | : /* no inputs */ | |
181 | : "%ecx", "%edx"); | |
0f23f75f MW |
182 | # elif CPUFAM_AMD64 |
183 | __asm__ ("movq %%rsp, %%rdx; subq $512, %%rsp; andq $~15, %%rsp\n" | |
184 | "fxsave (%%rsp)\n" | |
185 | "movl 160(%%rsp), %%eax; xorl $0xaaaa5555, 160(%%rsp)\n" | |
186 | "fxrstor (%%rsp); fxsave (%%rsp)\n" | |
187 | "movl 160(%%rsp), %%ecx; movl %%eax, 160(%%rsp)\n" | |
188 | "fxrstor (%%rsp); movq %%rdx, %%rsp\n" | |
189 | "xorl %%ecx, %%eax" | |
190 | : "=a" (f) | |
191 | : /* no inputs */ | |
192 | : "%ecx", "%rdx"); | |
193 | # else | |
194 | # error "I'm confused." | |
195 | # endif | |
196 | dispatch_debug("XMM registers %savailable", f ? "" : "not "); | |
acbe16df MW |
197 | return (f); |
198 | #else | |
fac645f7 | 199 | dispatch_debug("GNU inline assembler not available; can't check for XMM"); |
acbe16df MW |
200 | return (0); |
201 | #endif | |
202 | } | |
203 | ||
35b1eba8 MW |
204 | /* --- @rdrand_works_p@ --- * |
205 | * | |
206 | * | |
207 | * Arguments: --- | |
208 | * | |
209 | * Returns: Nonzero if the `rdrand' instruction actually works. Assumes | |
210 | * that it's already been verified to be safe to issue. | |
211 | */ | |
212 | ||
213 | #ifdef __GNUC__ | |
214 | static int rdrand(unsigned *x) | |
215 | { | |
216 | int i, rc; | |
217 | unsigned _t; | |
218 | ||
219 | i = 16; | |
220 | __asm__ ("" : "=g" (_t)); | |
221 | __asm__ ("0: rdrand %2; jc 1f; decl %1; jnz 0b\n" | |
222 | "mov $-1, %0; jmp 9f\n" | |
223 | "1: movl %2, (%3); xorl %0, %0\n" | |
224 | "9:" | |
225 | : "=r" (rc), "+r" (i), "+r" (_t) | |
226 | : "r" (x) | |
227 | : "cc"); | |
228 | return (rc); | |
229 | } | |
230 | #endif | |
231 | ||
232 | static int rdrand_works_p(void) | |
233 | { | |
234 | unsigned ref, x, i; | |
235 | ||
236 | /* Check that it doesn't always give the same answer. Try four times: this | |
237 | * will fail with probability %$2^{-128}$% with a truly random generator, | |
238 | * which seems fair enough. | |
239 | */ | |
240 | if (rdrand(&ref)) goto fail; | |
241 | for (i = 0; i < 4; i++) { | |
242 | if (rdrand(&x)) goto fail; | |
243 | if (x != ref) goto not_stuck; | |
244 | } | |
245 | dispatch_debug("RDRAND always returns 0x%08x!", ref); | |
246 | return (0); | |
247 | ||
248 | not_stuck: | |
249 | dispatch_debug("RDRAND instruction looks plausible"); | |
250 | return (1); | |
251 | ||
252 | fail: | |
253 | dispatch_debug("RDRAND instruction fails too often"); | |
254 | return (0); | |
255 | } | |
256 | ||
08e2be29 MW |
257 | #endif |
258 | ||
a02a22d4 MW |
259 | /*----- General feature probing using auxiliary vectors -------------------*/ |
260 | ||
261 | /* Try to find the system's definitions for auxiliary vector entries. */ | |
262 | #ifdef HAVE_SYS_AUXV_H | |
263 | # include <sys/auxv.h> | |
a0e9bb8a MW |
264 | #endif |
265 | #ifdef HAVE_LINUX_AUXVEC_H | |
266 | # include <linux/auxvec.h> | |
267 | #endif | |
268 | #ifdef HAVE_ASM_HWCAP_H | |
269 | # include <asm/hwcap.h> | |
a02a22d4 MW |
270 | #endif |
271 | ||
272 | /* The type of entries in the auxiliary vector. I'm assuming that `unsigned | |
273 | * long' matches each platform's word length; if this is false then we'll | |
274 | * need some host-specific tweaking here. | |
275 | */ | |
276 | union auxval { long i; unsigned long u; const void *p; }; | |
277 | struct auxentry { unsigned long type; union auxval value; }; | |
278 | ||
279 | /* Register each CPU family's interest in the auxiliary vector. Make sure | |
280 | * that the necessary entry types are defined. This is primarily ordered by | |
281 | * entry type to minimize duplication. | |
282 | */ | |
61bd904b MW |
283 | #if defined(AT_HWCAP) && CPUFAM_ARMEL |
284 | # define WANT_ANY 1 | |
285 | # define WANT_AT_HWCAP(_) _(AT_HWCAP, u, hwcap) | |
286 | #endif | |
a02a22d4 | 287 | |
e492db88 MW |
288 | #if defined(AT_HWCAP) && CPUFAM_ARM64 |
289 | # define WANT_ANY 1 | |
290 | # define WANT_AT_HWCAP(_) _(AT_HWCAP, u, hwcap) | |
291 | #endif | |
292 | ||
26e182fc MW |
293 | #if defined(AT_HWCAP2) && CPUFAM_ARMEL |
294 | # define WANT_ANY 1 | |
295 | # define WANT_AT_HWCAP2(_) _(AT_HWCAP2, u, hwcap2) | |
296 | #endif | |
297 | ||
a02a22d4 MW |
298 | /* If we couldn't find any interesting entries then we can switch all of this |
299 | * machinery off. Also do that if we have no means for atomic updates. | |
300 | */ | |
301 | #if WANT_ANY && CPU_DISPATCH_P | |
302 | ||
303 | /* The main output of this section is a bitmask of detected features. The | |
304 | * least significant bit will be set if we've tried to probe. Always access | |
305 | * this using `DISPATCH_LOAD' and `DISPATCH_STORE'. | |
306 | */ | |
307 | static unsigned hwcaps = 0; | |
308 | ||
309 | /* For each potentially interesting type which turned out not to exist or be | |
310 | * wanted, define a dummy macro for the sake of the next step. | |
311 | */ | |
312 | #ifndef WANT_AT_HWCAP | |
313 | # define WANT_AT_HWCAP(_) | |
314 | #endif | |
f013a4f2 MW |
315 | #ifndef WANT_AT_HWCAP2 |
316 | # define WANT_AT_HWCAP2(_) | |
317 | #endif | |
a02a22d4 MW |
318 | |
319 | /* For each CPU family, define two lists. | |
320 | * | |
321 | * * `WANTAUX' is a list of the `WANT_AT_MUMBLE' macros which the CPU | |
322 | * family tried to register interest in above. Each entry contains the | |
323 | * interesting auxiliary vector entry type, the name of the union branch | |
324 | * for its value, and the name of the slot in `struct auxprobe' in which | |
325 | * to store the value. | |
326 | * | |
327 | * * `CAPMAP' is a list describing the output features which the CPU family | |
328 | * intends to satisfy from the auxiliary vector. Each entry contains a | |
329 | * feature name suffix, and the token name (for `check_env'). | |
330 | */ | |
61bd904b MW |
331 | #if CPUFAM_ARMEL |
332 | # define WANTAUX(_) \ | |
26e182fc MW |
333 | WANT_AT_HWCAP(_) \ |
334 | WANT_AT_HWCAP2(_) | |
61bd904b MW |
335 | # define CAPMAP(_) \ |
336 | _(ARM_VFP, "arm:vfp") \ | |
337 | _(ARM_NEON, "arm:neon") \ | |
338 | _(ARM_V4, "arm:v4") \ | |
26e182fc | 339 | _(ARM_D32, "arm:d32") \ |
9e6a4409 MW |
340 | _(ARM_AES, "arm:aes") \ |
341 | _(ARM_PMULL, "arm:pmull") | |
61bd904b | 342 | #endif |
e492db88 MW |
343 | #if CPUFAM_ARM64 |
344 | # define WANTAUX(_) \ | |
345 | WANT_AT_HWCAP(_) | |
346 | # define CAPMAP(_) \ | |
9e6a4409 MW |
347 | _(ARM_AES, "arm:aes") \ |
348 | _(ARM_PMULL, "arm:pmull") | |
e492db88 | 349 | #endif |
a02a22d4 MW |
350 | |
351 | /* Build the bitmask for `hwcaps' from the `CAPMAP' list. */ | |
352 | enum { | |
353 | HFI_PROBED = 0, | |
354 | #define HFI__ENUM(feat, tok) HFI_##feat, | |
355 | CAPMAP(HFI__ENUM) | |
356 | #undef HFI__ENUM | |
357 | HFI__END | |
358 | }; | |
359 | enum { | |
360 | HF_PROBED = 1, | |
361 | #define HF__FLAG(feat, tok) HF_##feat = 1 << HFI_##feat, | |
362 | CAPMAP(HF__FLAG) | |
363 | #undef HF__FLAG | |
364 | HF__END | |
365 | }; | |
366 | ||
367 | /* Build a structure in which we can capture the interesting data from the | |
368 | * auxiliary vector. | |
369 | */ | |
370 | #define AUXUTYPE_i long | |
371 | #define AUXUTYPE_u unsigned long | |
372 | #define AUXUTYPE_p const void * | |
373 | struct auxprobe { | |
374 | #define AUXPROBE__SLOT(type, ubranch, slot) AUXUTYPE_##ubranch slot; | |
375 | WANTAUX(AUXPROBE__SLOT) | |
376 | #undef AUXPROBE_SLOT | |
377 | }; | |
378 | ||
379 | /* --- @probe_hwcaps@ --- * | |
380 | * | |
381 | * Arguments: --- | |
382 | * | |
383 | * Returns: --- | |
384 | * | |
385 | * Use: Attempt to find the auxiliary vector (which is well hidden) | |
386 | * and discover interesting features from it. | |
387 | */ | |
388 | ||
389 | static void probe_hwcaps(void) | |
390 | { | |
391 | unsigned hw = HF_PROBED; | |
392 | struct auxprobe probed = { 0 }; | |
393 | ||
394 | /* Populate `probed' with the information we manage to retrieve from the | |
395 | * auxiliary vector. Slots we couldn't find are left zero-valued. | |
396 | */ | |
397 | #if defined(HAVE_GETAUXVAL) | |
398 | /* Shiny new libc lets us request individual entry types. This is almost | |
399 | * too easy. | |
400 | */ | |
84850eec MW |
401 | # define CAP__GET(type, ubranch, slot) \ |
402 | probed.slot = (AUXUTYPE_##ubranch)getauxval(type); | |
a02a22d4 MW |
403 | WANTAUX(CAP__GET) |
404 | #else | |
405 | /* Otherwise we're a bit stuck, really. Modern Linux kernels make a copy | |
406 | * of the vector available in `/procc' so we could try that. | |
407 | * | |
408 | * The usual place is stuck on the end of the environment vector, but that | |
409 | * may well have moved, and we have no way of telling whether it has or | |
410 | * whether there was ever an auxiliary vector there at all; so don't do | |
411 | * that. | |
412 | */ | |
413 | { | |
414 | FILE *fp = 0; | |
415 | unsigned char *p = 0, *q = 0; | |
416 | const struct auxentry *a; | |
417 | size_t sz, off, n; | |
418 | ||
419 | /* Open the file and read it into a memory chunk. */ | |
420 | if ((fp = fopen("/proc/self/auxv", "rb")) == 0) goto clean; | |
421 | sz = 4096; off = 0; | |
422 | if ((p = malloc(sz)) == 0) goto clean; | |
423 | for (;;) { | |
424 | n = fread(p + off, 1, sz - off, fp); | |
425 | off += n; | |
426 | if (off < sz) break; | |
427 | sz *= 2; if ((q = realloc(p, sz)) == 0) break; | |
428 | p = q; | |
429 | } | |
430 | ||
431 | /* Work through the vector (or as much of it as we found) and extract the | |
432 | * types we're interested in. | |
433 | */ | |
434 | for (a = (const struct auxentry *)p, | |
435 | n = sz/sizeof(struct auxentry); | |
436 | n--; a++) { | |
437 | switch (a->type) { | |
438 | #define CAP__SWITCH(type, ubranch, slot) \ | |
439 | case type: probed.slot = a->value.ubranch; break; | |
440 | WANTAUX(CAP__SWITCH) | |
dfcb2a0b | 441 | case AT_NULL: goto clean; |
a02a22d4 MW |
442 | } |
443 | } | |
444 | ||
445 | clean: | |
446 | if (p) free(p); | |
447 | if (fp) fclose(fp); | |
448 | } | |
449 | #endif | |
450 | ||
451 | /* Each CPU family now has to pick through what was found and stashed in | |
452 | * `probed', and set the appropriate flag bits in `hw'. | |
453 | */ | |
61bd904b MW |
454 | #if CPUFAM_ARMEL |
455 | if (probed.hwcap & HWCAP_VFPv3) hw |= HF_ARM_VFP; | |
456 | if (probed.hwcap & HWCAP_NEON) hw |= HF_ARM_NEON; | |
457 | if (probed.hwcap & HWCAP_VFPD32) hw |= HF_ARM_D32; | |
458 | if (probed.hwcap & HWCAP_VFPv4) hw |= HF_ARM_V4; | |
26e182fc MW |
459 | # ifdef HWCAP2_AES |
460 | if (probed.hwcap2 & HWCAP2_AES) hw |= HF_ARM_AES; | |
461 | # endif | |
9e6a4409 MW |
462 | # ifdef HWCAP2_PMULL |
463 | if (probed.hwcap2 & HWCAP2_PMULL) hw |= HF_ARM_PMULL; | |
464 | # endif | |
61bd904b | 465 | #endif |
e492db88 MW |
466 | #if CPUFAM_ARM64 |
467 | if (probed.hwcap & HWCAP_AES) hw |= HF_ARM_AES; | |
9e6a4409 | 468 | if (probed.hwcap & HWCAP_PMULL) hw |= HF_ARM_PMULL; |
e492db88 | 469 | #endif |
a02a22d4 MW |
470 | |
471 | /* Store the bitmask of features we probed for everyone to see. */ | |
472 | DISPATCH_STORE(hwcaps, hw); | |
473 | ||
474 | /* Finally, make a report about the things we found. (Doing this earlier | |
475 | * will pointlessly widen the window in which multiple threads will do the | |
476 | * above auxiliary-vector probing.) | |
477 | */ | |
478 | #define CAP__DEBUG(feat, tok) \ | |
479 | dispatch_debug("check auxv for feature `%s': %s", tok, \ | |
480 | hw & HF_##feat ? "available" : "absent"); | |
481 | CAPMAP(CAP__DEBUG) | |
482 | #undef CAP__DEBUG | |
483 | } | |
484 | ||
485 | /* --- @get_hwcaps@ --- * | |
486 | * | |
487 | * Arguments: --- | |
488 | * | |
489 | * Returns: A mask of hardware capabilities and other features, as probed | |
490 | * from the auxiliary vector. | |
491 | */ | |
492 | ||
493 | static unsigned get_hwcaps(void) | |
494 | { | |
495 | unsigned hw; | |
496 | ||
497 | DISPATCH_LOAD(hwcaps, hw); | |
498 | if (!(hwcaps & HF_PROBED)) { probe_hwcaps(); DISPATCH_LOAD(hwcaps, hw); } | |
499 | return (hw); | |
500 | } | |
501 | ||
502 | #endif | |
503 | ||
d26ad211 MW |
504 | /*----- External interface ------------------------------------------------*/ |
505 | ||
fac645f7 MW |
506 | /* --- @dispatch_debug@ --- * |
507 | * | |
508 | * Arguments: @const char *fmt@ = a format string | |
509 | * @...@ = additional arguments | |
510 | * | |
511 | * Returns: --- | |
512 | * | |
513 | * Use: Writes a formatted message to standard output if dispatch | |
514 | * debugging is enabled. | |
515 | */ | |
516 | ||
517 | void dispatch_debug(const char *fmt, ...) | |
518 | { | |
519 | va_list ap; | |
520 | const char *e = getenv("CATACOMB_CPUDISPATCH_DEBUG"); | |
521 | ||
522 | if (e && *e != 'n' && *e != '0') { | |
523 | va_start(ap, fmt); | |
524 | fputs("Catacomb CPUDISPATCH: ", stderr); | |
525 | vfprintf(stderr, fmt, ap); | |
526 | fputc('\n', stderr); | |
527 | va_end(ap); | |
528 | } | |
529 | } | |
530 | ||
08e2be29 MW |
531 | /* --- @check_env@ --- * |
532 | * | |
533 | * Arguments: @const char *ftok@ = feature token | |
534 | * | |
535 | * Returns: Zero if the feature is forced off; positive if it's forced | |
536 | * on; negative if the user hasn't decided. | |
537 | * | |
538 | * Use: Checks the environment variable `CATACOMB_CPUFEAT' for the | |
539 | * feature token @ftok@. The variable, if it exists, should be | |
540 | * a space-separated sequence of `+tok' and `-tok' items. These | |
541 | * tokens may end in `*', which matches any suffix. | |
542 | */ | |
543 | ||
544 | static int IGNORABLE check_env(const char *ftok) | |
545 | { | |
546 | const char *p, *q, *pp; | |
547 | int d; | |
548 | ||
549 | p = getenv("CATACOMB_CPUFEAT"); | |
550 | if (!p) return (-1); | |
551 | ||
552 | for (;;) { | |
553 | while (isspace((unsigned char)*p)) p++; | |
554 | if (!*p) return (-1); | |
555 | switch (*p) { | |
556 | case '+': d = +1; p++; break; | |
557 | case '-': d = 0; p++; break; | |
558 | default: d = -1; break; | |
559 | } | |
560 | for (q = p; *q && !isspace((unsigned char)*q); q++); | |
561 | if (d >= 0) { | |
562 | for (pp = ftok; p < q && *pp && *p == *pp; p++, pp++); | |
563 | if ((p == q && !*pp) || (*p == '*' && p + 1 == q)) return (d); | |
564 | } | |
565 | p = q; | |
566 | } | |
567 | return (-1); | |
568 | } | |
569 | ||
570 | /* --- @cpu_feature_p@ --- * | |
571 | * | |
572 | * Arguments: @unsigned feat@ = a @CPUFEAT_...@ code | |
573 | * | |
574 | * Returns: Nonzero if the feature is available. | |
575 | */ | |
576 | ||
577 | #include <stdio.h> | |
578 | ||
fac645f7 MW |
579 | static int IGNORABLE |
580 | feat_debug(const char *ftok, const char *check, int verdict) | |
581 | { | |
582 | if (verdict >= 0) { | |
583 | dispatch_debug("feature `%s': %s -> %s", ftok, check, | |
584 | verdict ? "available" : "absent"); | |
585 | } | |
586 | return (verdict); | |
587 | } | |
588 | ||
08e2be29 MW |
589 | int cpu_feature_p(int feat) |
590 | { | |
591 | int IGNORABLE f; | |
592 | IGNORE(f); | |
fac645f7 MW |
593 | #define CASE_CPUFEAT(feat, ftok, cond) case CPUFEAT_##feat: \ |
594 | if ((f = feat_debug(ftok, "environment override", \ | |
595 | check_env(ftok))) >= 0) \ | |
596 | return (f); \ | |
597 | else \ | |
598 | return (feat_debug(ftok, "runtime probe", cond)); | |
08e2be29 MW |
599 | |
600 | switch (feat) { | |
0f23f75f | 601 | #if CPUFAM_X86 || CPUFAM_AMD64 |
fac645f7 | 602 | CASE_CPUFEAT(X86_SSE2, "x86:sse2", |
4fab22c2 MW |
603 | cpuid_features_p(CPUID1D_SSE2, 0) && |
604 | xmm_registers_available_p()); | |
fac645f7 | 605 | CASE_CPUFEAT(X86_AESNI, "x86:aesni", |
4fab22c2 MW |
606 | cpuid_features_p(CPUID1D_SSE2, CPUID1C_AESNI) && |
607 | xmm_registers_available_p()); | |
d25653be | 608 | CASE_CPUFEAT(X86_RDRAND, "x86:rdrand", |
35b1eba8 | 609 | cpuid_features_p(0, CPUID1C_RDRAND) && rdrand_works_p()); |
b9b279b4 | 610 | CASE_CPUFEAT(X86_AVX, "x86:avx", |
6af2607b MW |
611 | cpuid_features_p(0, CPUID1C_AVX) && |
612 | xmm_registers_available_p()); | |
9e6a4409 | 613 | CASE_CPUFEAT(X86_SSSE3, "x86:ssse3", |
6af2607b MW |
614 | cpuid_features_p(0, CPUID1C_SSSE3) && |
615 | xmm_registers_available_p()); | |
9e6a4409 | 616 | CASE_CPUFEAT(X86_PCLMUL, "x86:pclmul", |
6af2607b MW |
617 | cpuid_features_p(0, CPUID1C_PCLMUL) && |
618 | xmm_registers_available_p()); | |
08e2be29 | 619 | #endif |
a02a22d4 MW |
620 | #ifdef CAPMAP |
621 | # define FEATP__CASE(feat, tok) \ | |
0aec0658 | 622 | CASE_CPUFEAT(feat, tok, get_hwcaps() & HF_##feat) |
a02a22d4 MW |
623 | CAPMAP(FEATP__CASE) |
624 | #undef FEATP__CASE | |
625 | #endif | |
08e2be29 | 626 | default: |
fac645f7 | 627 | dispatch_debug("denying unknown feature %d", feat); |
08e2be29 MW |
628 | return (0); |
629 | } | |
fac645f7 | 630 | #undef CASE_CPUFEAT |
08e2be29 MW |
631 | } |
632 | ||
633 | /*----- That's all, folks -------------------------------------------------*/ |