fpu.c revision 335090
1/*- 2 * Copyright (c) 1990 William Jolitz. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 4. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * from: @(#)npx.c 7.2 (Berkeley) 5/12/91 31 */ 32 33#include <sys/cdefs.h> 34__FBSDID("$FreeBSD: stable/11/sys/amd64/amd64/fpu.c 335090 2018-06-13 21:10:33Z kib $"); 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/bus.h> 39#include <sys/kernel.h> 40#include <sys/lock.h> 41#include <sys/malloc.h> 42#include <sys/module.h> 43#include <sys/mutex.h> 44#include <sys/mutex.h> 45#include <sys/proc.h> 46#include <sys/sysctl.h> 47#include <machine/bus.h> 48#include <sys/rman.h> 49#include <sys/signalvar.h> 50#include <vm/uma.h> 51 52#include <machine/cputypes.h> 53#include <machine/frame.h> 54#include <machine/intr_machdep.h> 55#include <machine/md_var.h> 56#include <machine/pcb.h> 57#include <machine/psl.h> 58#include <machine/resource.h> 59#include <machine/specialreg.h> 60#include <machine/segments.h> 61#include <machine/ucontext.h> 62 63/* 64 * Floating point support. 65 */ 66 67#if defined(__GNUCLIKE_ASM) && !defined(lint) 68 69#define fldcw(cw) __asm __volatile("fldcw %0" : : "m" (cw)) 70#define fnclex() __asm __volatile("fnclex") 71#define fninit() __asm __volatile("fninit") 72#define fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 73#define fnstsw(addr) __asm __volatile("fnstsw %0" : "=am" (*(addr))) 74#define fxrstor(addr) __asm __volatile("fxrstor %0" : : "m" (*(addr))) 75#define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr))) 76#define ldmxcsr(csr) __asm __volatile("ldmxcsr %0" : : "m" (csr)) 77#define stmxcsr(addr) __asm __volatile("stmxcsr %0" : : "m" (*(addr))) 78 79static __inline void 80xrstor(char *addr, uint64_t mask) 81{ 82 uint32_t low, hi; 83 84 low = mask; 85 hi = mask >> 32; 86 __asm __volatile("xrstor %0" : : "m" (*addr), "a" (low), "d" (hi)); 87} 88 89static __inline void 90xsave(char *addr, uint64_t mask) 91{ 92 uint32_t low, hi; 93 94 low = mask; 95 hi = mask >> 32; 96 __asm __volatile("xsave %0" : "=m" (*addr) : "a" (low), "d" (hi) : 97 "memory"); 98} 99 100#else /* !(__GNUCLIKE_ASM && !lint) */ 101 102void fldcw(u_short cw); 103void fnclex(void); 104void fninit(void); 105void fnstcw(caddr_t addr); 106void fnstsw(caddr_t addr); 107void fxsave(caddr_t addr); 108void fxrstor(caddr_t addr); 109void ldmxcsr(u_int csr); 110void stmxcsr(u_int *csr); 111void xrstor(char *addr, uint64_t mask); 112void xsave(char *addr, uint64_t mask); 113 114#endif /* __GNUCLIKE_ASM && !lint */ 115 116#define start_emulating() load_cr0(rcr0() | CR0_TS) 117#define stop_emulating() clts() 118 119CTASSERT(sizeof(struct savefpu) == 512); 120CTASSERT(sizeof(struct xstate_hdr) == 64); 121CTASSERT(sizeof(struct savefpu_ymm) == 832); 122 123/* 124 * This requirement is to make it easier for asm code to calculate 125 * offset of the fpu save area from the pcb address. FPU save area 126 * must be 64-byte aligned. 127 */ 128CTASSERT(sizeof(struct pcb) % XSAVE_AREA_ALIGN == 0); 129 130/* 131 * Ensure the copy of XCR0 saved in a core is contained in the padding 132 * area. 133 */ 134CTASSERT(X86_XSTATE_XCR0_OFFSET >= offsetof(struct savefpu, sv_pad) && 135 X86_XSTATE_XCR0_OFFSET + sizeof(uint64_t) <= sizeof(struct savefpu)); 136 137static void fpu_clean_state(void); 138 139SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD, 140 SYSCTL_NULL_INT_PTR, 1, "Floating point instructions executed in hardware"); 141 142int lazy_fpu_switch = 0; 143SYSCTL_INT(_hw, OID_AUTO, lazy_fpu_switch, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, 144 &lazy_fpu_switch, 0, 145 "Lazily load FPU context after context switch"); 146 147int use_xsave; /* non-static for cpu_switch.S */ 148uint64_t xsave_mask; /* the same */ 149static uma_zone_t fpu_save_area_zone; 150static struct savefpu *fpu_initialstate; 151 152struct xsave_area_elm_descr { 153 u_int offset; 154 u_int size; 155} *xsave_area_desc; 156 157void 158fpusave(void *addr) 159{ 160 161 if (use_xsave) 162 xsave((char *)addr, xsave_mask); 163 else 164 fxsave((char *)addr); 165} 166 167void 168fpurestore(void *addr) 169{ 170 171 if (use_xsave) 172 xrstor((char *)addr, xsave_mask); 173 else 174 fxrstor((char *)addr); 175} 176 177void 178fpususpend(void *addr) 179{ 180 u_long cr0; 181 182 cr0 = rcr0(); 183 stop_emulating(); 184 fpusave(addr); 185 load_cr0(cr0); 186} 187 188void 189fpuresume(void *addr) 190{ 191 u_long cr0; 192 193 cr0 = rcr0(); 194 stop_emulating(); 195 fninit(); 196 if (use_xsave) 197 load_xcr(XCR0, xsave_mask); 198 fpurestore(addr); 199 load_cr0(cr0); 200} 201 202/* 203 * Enable XSAVE if supported and allowed by user. 204 * Calculate the xsave_mask. 205 */ 206static void 207fpuinit_bsp1(void) 208{ 209 u_int cp[4]; 210 uint64_t xsave_mask_user; 211 212 TUNABLE_INT_FETCH("hw.lazy_fpu_switch", &lazy_fpu_switch); 213 if ((cpu_feature2 & CPUID2_XSAVE) != 0) { 214 use_xsave = 1; 215 TUNABLE_INT_FETCH("hw.use_xsave", &use_xsave); 216 } 217 if (!use_xsave) 218 return; 219 220 cpuid_count(0xd, 0x0, cp); 221 xsave_mask = XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE; 222 if ((cp[0] & xsave_mask) != xsave_mask) 223 panic("CPU0 does not support X87 or SSE: %x", cp[0]); 224 xsave_mask = ((uint64_t)cp[3] << 32) | cp[0]; 225 xsave_mask_user = xsave_mask; 226 TUNABLE_ULONG_FETCH("hw.xsave_mask", &xsave_mask_user); 227 xsave_mask_user |= XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE; 228 xsave_mask &= xsave_mask_user; 229 if ((xsave_mask & XFEATURE_AVX512) != XFEATURE_AVX512) 230 xsave_mask &= ~XFEATURE_AVX512; 231 if ((xsave_mask & XFEATURE_MPX) != XFEATURE_MPX) 232 xsave_mask &= ~XFEATURE_MPX; 233 234 cpuid_count(0xd, 0x1, cp); 235 if ((cp[0] & CPUID_EXTSTATE_XSAVEOPT) != 0) { 236 /* 237 * Patch the XSAVE instruction in the cpu_switch code 238 * to XSAVEOPT. We assume that XSAVE encoding used 239 * REX byte, and set the bit 4 of the r/m byte. 240 */ 241 ctx_switch_xsave[3] |= 0x10; 242 } 243} 244 245/* 246 * Calculate the fpu save area size. 247 */ 248static void 249fpuinit_bsp2(void) 250{ 251 u_int cp[4]; 252 253 if (use_xsave) { 254 cpuid_count(0xd, 0x0, cp); 255 cpu_max_ext_state_size = cp[1]; 256 257 /* 258 * Reload the cpu_feature2, since we enabled OSXSAVE. 259 */ 260 do_cpuid(1, cp); 261 cpu_feature2 = cp[2]; 262 } else 263 cpu_max_ext_state_size = sizeof(struct savefpu); 264} 265 266/* 267 * Initialize the floating point unit. 268 */ 269void 270fpuinit(void) 271{ 272 register_t saveintr; 273 u_int mxcsr; 274 u_short control; 275 276 if (IS_BSP()) 277 fpuinit_bsp1(); 278 279 if (use_xsave) { 280 load_cr4(rcr4() | CR4_XSAVE); 281 load_xcr(XCR0, xsave_mask); 282 } 283 284 /* 285 * XCR0 shall be set up before CPU can report the save area size. 286 */ 287 if (IS_BSP()) 288 fpuinit_bsp2(); 289 290 /* 291 * It is too early for critical_enter() to work on AP. 292 */ 293 saveintr = intr_disable(); 294 stop_emulating(); 295 fninit(); 296 control = __INITIAL_FPUCW__; 297 fldcw(control); 298 mxcsr = __INITIAL_MXCSR__; 299 ldmxcsr(mxcsr); 300 start_emulating(); 301 intr_restore(saveintr); 302} 303 304/* 305 * On the boot CPU we generate a clean state that is used to 306 * initialize the floating point unit when it is first used by a 307 * process. 308 */ 309static void 310fpuinitstate(void *arg __unused) 311{ 312 register_t saveintr; 313 int cp[4], i, max_ext_n; 314 315 fpu_initialstate = malloc(cpu_max_ext_state_size, M_DEVBUF, 316 M_WAITOK | M_ZERO); 317 saveintr = intr_disable(); 318 stop_emulating(); 319 320 fpusave(fpu_initialstate); 321 if (fpu_initialstate->sv_env.en_mxcsr_mask) 322 cpu_mxcsr_mask = fpu_initialstate->sv_env.en_mxcsr_mask; 323 else 324 cpu_mxcsr_mask = 0xFFBF; 325 326 /* 327 * The fninit instruction does not modify XMM registers or x87 328 * registers (MM/ST). The fpusave call dumped the garbage 329 * contained in the registers after reset to the initial state 330 * saved. Clear XMM and x87 registers file image to make the 331 * startup program state and signal handler XMM/x87 register 332 * content predictable. 333 */ 334 bzero(fpu_initialstate->sv_fp, sizeof(fpu_initialstate->sv_fp)); 335 bzero(fpu_initialstate->sv_xmm, sizeof(fpu_initialstate->sv_xmm)); 336 337 /* 338 * Create a table describing the layout of the CPU Extended 339 * Save Area. 340 */ 341 if (use_xsave) { 342 max_ext_n = flsl(xsave_mask); 343 xsave_area_desc = malloc(max_ext_n * sizeof(struct 344 xsave_area_elm_descr), M_DEVBUF, M_WAITOK | M_ZERO); 345 /* x87 state */ 346 xsave_area_desc[0].offset = 0; 347 xsave_area_desc[0].size = 160; 348 /* XMM */ 349 xsave_area_desc[1].offset = 160; 350 xsave_area_desc[1].size = 288 - 160; 351 352 for (i = 2; i < max_ext_n; i++) { 353 cpuid_count(0xd, i, cp); 354 xsave_area_desc[i].offset = cp[1]; 355 xsave_area_desc[i].size = cp[0]; 356 } 357 } 358 359 fpu_save_area_zone = uma_zcreate("FPU_save_area", 360 cpu_max_ext_state_size, NULL, NULL, NULL, NULL, 361 XSAVE_AREA_ALIGN - 1, 0); 362 363 start_emulating(); 364 intr_restore(saveintr); 365} 366/* EFIRT needs this to be initialized before we can enter our EFI environment */ 367SYSINIT(fpuinitstate, SI_SUB_DRIVERS, SI_ORDER_FIRST, fpuinitstate, NULL); 368 369/* 370 * Free coprocessor (if we have it). 371 */ 372void 373fpuexit(struct thread *td) 374{ 375 376 critical_enter(); 377 if (curthread == PCPU_GET(fpcurthread)) { 378 stop_emulating(); 379 fpusave(curpcb->pcb_save); 380 start_emulating(); 381 PCPU_SET(fpcurthread, NULL); 382 } 383 critical_exit(); 384} 385 386int 387fpuformat(void) 388{ 389 390 return (_MC_FPFMT_XMM); 391} 392 393/* 394 * The following mechanism is used to ensure that the FPE_... value 395 * that is passed as a trapcode to the signal handler of the user 396 * process does not have more than one bit set. 397 * 398 * Multiple bits may be set if the user process modifies the control 399 * word while a status word bit is already set. While this is a sign 400 * of bad coding, we have no choise than to narrow them down to one 401 * bit, since we must not send a trapcode that is not exactly one of 402 * the FPE_ macros. 403 * 404 * The mechanism has a static table with 127 entries. Each combination 405 * of the 7 FPU status word exception bits directly translates to a 406 * position in this table, where a single FPE_... value is stored. 407 * This FPE_... value stored there is considered the "most important" 408 * of the exception bits and will be sent as the signal code. The 409 * precedence of the bits is based upon Intel Document "Numerical 410 * Applications", Chapter "Special Computational Situations". 411 * 412 * The macro to choose one of these values does these steps: 1) Throw 413 * away status word bits that cannot be masked. 2) Throw away the bits 414 * currently masked in the control word, assuming the user isn't 415 * interested in them anymore. 3) Reinsert status word bit 7 (stack 416 * fault) if it is set, which cannot be masked but must be presered. 417 * 4) Use the remaining bits to point into the trapcode table. 418 * 419 * The 6 maskable bits in order of their preference, as stated in the 420 * above referenced Intel manual: 421 * 1 Invalid operation (FP_X_INV) 422 * 1a Stack underflow 423 * 1b Stack overflow 424 * 1c Operand of unsupported format 425 * 1d SNaN operand. 426 * 2 QNaN operand (not an exception, irrelavant here) 427 * 3 Any other invalid-operation not mentioned above or zero divide 428 * (FP_X_INV, FP_X_DZ) 429 * 4 Denormal operand (FP_X_DNML) 430 * 5 Numeric over/underflow (FP_X_OFL, FP_X_UFL) 431 * 6 Inexact result (FP_X_IMP) 432 */ 433static char fpetable[128] = { 434 0, 435 FPE_FLTINV, /* 1 - INV */ 436 FPE_FLTUND, /* 2 - DNML */ 437 FPE_FLTINV, /* 3 - INV | DNML */ 438 FPE_FLTDIV, /* 4 - DZ */ 439 FPE_FLTINV, /* 5 - INV | DZ */ 440 FPE_FLTDIV, /* 6 - DNML | DZ */ 441 FPE_FLTINV, /* 7 - INV | DNML | DZ */ 442 FPE_FLTOVF, /* 8 - OFL */ 443 FPE_FLTINV, /* 9 - INV | OFL */ 444 FPE_FLTUND, /* A - DNML | OFL */ 445 FPE_FLTINV, /* B - INV | DNML | OFL */ 446 FPE_FLTDIV, /* C - DZ | OFL */ 447 FPE_FLTINV, /* D - INV | DZ | OFL */ 448 FPE_FLTDIV, /* E - DNML | DZ | OFL */ 449 FPE_FLTINV, /* F - INV | DNML | DZ | OFL */ 450 FPE_FLTUND, /* 10 - UFL */ 451 FPE_FLTINV, /* 11 - INV | UFL */ 452 FPE_FLTUND, /* 12 - DNML | UFL */ 453 FPE_FLTINV, /* 13 - INV | DNML | UFL */ 454 FPE_FLTDIV, /* 14 - DZ | UFL */ 455 FPE_FLTINV, /* 15 - INV | DZ | UFL */ 456 FPE_FLTDIV, /* 16 - DNML | DZ | UFL */ 457 FPE_FLTINV, /* 17 - INV | DNML | DZ | UFL */ 458 FPE_FLTOVF, /* 18 - OFL | UFL */ 459 FPE_FLTINV, /* 19 - INV | OFL | UFL */ 460 FPE_FLTUND, /* 1A - DNML | OFL | UFL */ 461 FPE_FLTINV, /* 1B - INV | DNML | OFL | UFL */ 462 FPE_FLTDIV, /* 1C - DZ | OFL | UFL */ 463 FPE_FLTINV, /* 1D - INV | DZ | OFL | UFL */ 464 FPE_FLTDIV, /* 1E - DNML | DZ | OFL | UFL */ 465 FPE_FLTINV, /* 1F - INV | DNML | DZ | OFL | UFL */ 466 FPE_FLTRES, /* 20 - IMP */ 467 FPE_FLTINV, /* 21 - INV | IMP */ 468 FPE_FLTUND, /* 22 - DNML | IMP */ 469 FPE_FLTINV, /* 23 - INV | DNML | IMP */ 470 FPE_FLTDIV, /* 24 - DZ | IMP */ 471 FPE_FLTINV, /* 25 - INV | DZ | IMP */ 472 FPE_FLTDIV, /* 26 - DNML | DZ | IMP */ 473 FPE_FLTINV, /* 27 - INV | DNML | DZ | IMP */ 474 FPE_FLTOVF, /* 28 - OFL | IMP */ 475 FPE_FLTINV, /* 29 - INV | OFL | IMP */ 476 FPE_FLTUND, /* 2A - DNML | OFL | IMP */ 477 FPE_FLTINV, /* 2B - INV | DNML | OFL | IMP */ 478 FPE_FLTDIV, /* 2C - DZ | OFL | IMP */ 479 FPE_FLTINV, /* 2D - INV | DZ | OFL | IMP */ 480 FPE_FLTDIV, /* 2E - DNML | DZ | OFL | IMP */ 481 FPE_FLTINV, /* 2F - INV | DNML | DZ | OFL | IMP */ 482 FPE_FLTUND, /* 30 - UFL | IMP */ 483 FPE_FLTINV, /* 31 - INV | UFL | IMP */ 484 FPE_FLTUND, /* 32 - DNML | UFL | IMP */ 485 FPE_FLTINV, /* 33 - INV | DNML | UFL | IMP */ 486 FPE_FLTDIV, /* 34 - DZ | UFL | IMP */ 487 FPE_FLTINV, /* 35 - INV | DZ | UFL | IMP */ 488 FPE_FLTDIV, /* 36 - DNML | DZ | UFL | IMP */ 489 FPE_FLTINV, /* 37 - INV | DNML | DZ | UFL | IMP */ 490 FPE_FLTOVF, /* 38 - OFL | UFL | IMP */ 491 FPE_FLTINV, /* 39 - INV | OFL | UFL | IMP */ 492 FPE_FLTUND, /* 3A - DNML | OFL | UFL | IMP */ 493 FPE_FLTINV, /* 3B - INV | DNML | OFL | UFL | IMP */ 494 FPE_FLTDIV, /* 3C - DZ | OFL | UFL | IMP */ 495 FPE_FLTINV, /* 3D - INV | DZ | OFL | UFL | IMP */ 496 FPE_FLTDIV, /* 3E - DNML | DZ | OFL | UFL | IMP */ 497 FPE_FLTINV, /* 3F - INV | DNML | DZ | OFL | UFL | IMP */ 498 FPE_FLTSUB, /* 40 - STK */ 499 FPE_FLTSUB, /* 41 - INV | STK */ 500 FPE_FLTUND, /* 42 - DNML | STK */ 501 FPE_FLTSUB, /* 43 - INV | DNML | STK */ 502 FPE_FLTDIV, /* 44 - DZ | STK */ 503 FPE_FLTSUB, /* 45 - INV | DZ | STK */ 504 FPE_FLTDIV, /* 46 - DNML | DZ | STK */ 505 FPE_FLTSUB, /* 47 - INV | DNML | DZ | STK */ 506 FPE_FLTOVF, /* 48 - OFL | STK */ 507 FPE_FLTSUB, /* 49 - INV | OFL | STK */ 508 FPE_FLTUND, /* 4A - DNML | OFL | STK */ 509 FPE_FLTSUB, /* 4B - INV | DNML | OFL | STK */ 510 FPE_FLTDIV, /* 4C - DZ | OFL | STK */ 511 FPE_FLTSUB, /* 4D - INV | DZ | OFL | STK */ 512 FPE_FLTDIV, /* 4E - DNML | DZ | OFL | STK */ 513 FPE_FLTSUB, /* 4F - INV | DNML | DZ | OFL | STK */ 514 FPE_FLTUND, /* 50 - UFL | STK */ 515 FPE_FLTSUB, /* 51 - INV | UFL | STK */ 516 FPE_FLTUND, /* 52 - DNML | UFL | STK */ 517 FPE_FLTSUB, /* 53 - INV | DNML | UFL | STK */ 518 FPE_FLTDIV, /* 54 - DZ | UFL | STK */ 519 FPE_FLTSUB, /* 55 - INV | DZ | UFL | STK */ 520 FPE_FLTDIV, /* 56 - DNML | DZ | UFL | STK */ 521 FPE_FLTSUB, /* 57 - INV | DNML | DZ | UFL | STK */ 522 FPE_FLTOVF, /* 58 - OFL | UFL | STK */ 523 FPE_FLTSUB, /* 59 - INV | OFL | UFL | STK */ 524 FPE_FLTUND, /* 5A - DNML | OFL | UFL | STK */ 525 FPE_FLTSUB, /* 5B - INV | DNML | OFL | UFL | STK */ 526 FPE_FLTDIV, /* 5C - DZ | OFL | UFL | STK */ 527 FPE_FLTSUB, /* 5D - INV | DZ | OFL | UFL | STK */ 528 FPE_FLTDIV, /* 5E - DNML | DZ | OFL | UFL | STK */ 529 FPE_FLTSUB, /* 5F - INV | DNML | DZ | OFL | UFL | STK */ 530 FPE_FLTRES, /* 60 - IMP | STK */ 531 FPE_FLTSUB, /* 61 - INV | IMP | STK */ 532 FPE_FLTUND, /* 62 - DNML | IMP | STK */ 533 FPE_FLTSUB, /* 63 - INV | DNML | IMP | STK */ 534 FPE_FLTDIV, /* 64 - DZ | IMP | STK */ 535 FPE_FLTSUB, /* 65 - INV | DZ | IMP | STK */ 536 FPE_FLTDIV, /* 66 - DNML | DZ | IMP | STK */ 537 FPE_FLTSUB, /* 67 - INV | DNML | DZ | IMP | STK */ 538 FPE_FLTOVF, /* 68 - OFL | IMP | STK */ 539 FPE_FLTSUB, /* 69 - INV | OFL | IMP | STK */ 540 FPE_FLTUND, /* 6A - DNML | OFL | IMP | STK */ 541 FPE_FLTSUB, /* 6B - INV | DNML | OFL | IMP | STK */ 542 FPE_FLTDIV, /* 6C - DZ | OFL | IMP | STK */ 543 FPE_FLTSUB, /* 6D - INV | DZ | OFL | IMP | STK */ 544 FPE_FLTDIV, /* 6E - DNML | DZ | OFL | IMP | STK */ 545 FPE_FLTSUB, /* 6F - INV | DNML | DZ | OFL | IMP | STK */ 546 FPE_FLTUND, /* 70 - UFL | IMP | STK */ 547 FPE_FLTSUB, /* 71 - INV | UFL | IMP | STK */ 548 FPE_FLTUND, /* 72 - DNML | UFL | IMP | STK */ 549 FPE_FLTSUB, /* 73 - INV | DNML | UFL | IMP | STK */ 550 FPE_FLTDIV, /* 74 - DZ | UFL | IMP | STK */ 551 FPE_FLTSUB, /* 75 - INV | DZ | UFL | IMP | STK */ 552 FPE_FLTDIV, /* 76 - DNML | DZ | UFL | IMP | STK */ 553 FPE_FLTSUB, /* 77 - INV | DNML | DZ | UFL | IMP | STK */ 554 FPE_FLTOVF, /* 78 - OFL | UFL | IMP | STK */ 555 FPE_FLTSUB, /* 79 - INV | OFL | UFL | IMP | STK */ 556 FPE_FLTUND, /* 7A - DNML | OFL | UFL | IMP | STK */ 557 FPE_FLTSUB, /* 7B - INV | DNML | OFL | UFL | IMP | STK */ 558 FPE_FLTDIV, /* 7C - DZ | OFL | UFL | IMP | STK */ 559 FPE_FLTSUB, /* 7D - INV | DZ | OFL | UFL | IMP | STK */ 560 FPE_FLTDIV, /* 7E - DNML | DZ | OFL | UFL | IMP | STK */ 561 FPE_FLTSUB, /* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */ 562}; 563 564/* 565 * Read the FP status and control words, then generate si_code value 566 * for SIGFPE. The error code chosen will be one of the 567 * FPE_... macros. It will be sent as the second argument to old 568 * BSD-style signal handlers and as "siginfo_t->si_code" (second 569 * argument) to SA_SIGINFO signal handlers. 570 * 571 * Some time ago, we cleared the x87 exceptions with FNCLEX there. 572 * Clearing exceptions was necessary mainly to avoid IRQ13 bugs. The 573 * usermode code which understands the FPU hardware enough to enable 574 * the exceptions, can also handle clearing the exception state in the 575 * handler. The only consequence of not clearing the exception is the 576 * rethrow of the SIGFPE on return from the signal handler and 577 * reexecution of the corresponding instruction. 578 * 579 * For XMM traps, the exceptions were never cleared. 580 */ 581int 582fputrap_x87(void) 583{ 584 struct savefpu *pcb_save; 585 u_short control, status; 586 587 critical_enter(); 588 589 /* 590 * Interrupt handling (for another interrupt) may have pushed the 591 * state to memory. Fetch the relevant parts of the state from 592 * wherever they are. 593 */ 594 if (PCPU_GET(fpcurthread) != curthread) { 595 pcb_save = curpcb->pcb_save; 596 control = pcb_save->sv_env.en_cw; 597 status = pcb_save->sv_env.en_sw; 598 } else { 599 fnstcw(&control); 600 fnstsw(&status); 601 } 602 603 critical_exit(); 604 return (fpetable[status & ((~control & 0x3f) | 0x40)]); 605} 606 607int 608fputrap_sse(void) 609{ 610 u_int mxcsr; 611 612 critical_enter(); 613 if (PCPU_GET(fpcurthread) != curthread) 614 mxcsr = curpcb->pcb_save->sv_env.en_mxcsr; 615 else 616 stmxcsr(&mxcsr); 617 critical_exit(); 618 return (fpetable[(mxcsr & (~mxcsr >> 7)) & 0x3f]); 619} 620 621static void 622restore_fpu_curthread(struct thread *td) 623{ 624 struct pcb *pcb; 625 626 /* 627 * Record new context early in case frstor causes a trap. 628 */ 629 PCPU_SET(fpcurthread, td); 630 631 stop_emulating(); 632 fpu_clean_state(); 633 pcb = td->td_pcb; 634 635 if ((pcb->pcb_flags & PCB_FPUINITDONE) == 0) { 636 /* 637 * This is the first time this thread has used the FPU or 638 * the PCB doesn't contain a clean FPU state. Explicitly 639 * load an initial state. 640 * 641 * We prefer to restore the state from the actual save 642 * area in PCB instead of directly loading from 643 * fpu_initialstate, to ignite the XSAVEOPT 644 * tracking engine. 645 */ 646 bcopy(fpu_initialstate, pcb->pcb_save, 647 cpu_max_ext_state_size); 648 fpurestore(pcb->pcb_save); 649 if (pcb->pcb_initial_fpucw != __INITIAL_FPUCW__) 650 fldcw(pcb->pcb_initial_fpucw); 651 if (PCB_USER_FPU(pcb)) 652 set_pcb_flags(pcb, PCB_FPUINITDONE | 653 PCB_USERFPUINITDONE); 654 else 655 set_pcb_flags(pcb, PCB_FPUINITDONE); 656 } else 657 fpurestore(pcb->pcb_save); 658} 659 660/* 661 * Device Not Available (DNA, #NM) exception handler. 662 * 663 * It would be better to switch FP context here (if curthread != 664 * fpcurthread) and not necessarily for every context switch, but it 665 * is too hard to access foreign pcb's. 666 */ 667void 668fpudna(void) 669{ 670 struct thread *td; 671 672 td = curthread; 673 /* 674 * This handler is entered with interrupts enabled, so context 675 * switches may occur before critical_enter() is executed. If 676 * a context switch occurs, then when we regain control, our 677 * state will have been completely restored. The CPU may 678 * change underneath us, but the only part of our context that 679 * lives in the CPU is CR0.TS and that will be "restored" by 680 * setting it on the new CPU. 681 */ 682 critical_enter(); 683 684 KASSERT((curpcb->pcb_flags & PCB_FPUNOSAVE) == 0, 685 ("fpudna while in fpu_kern_enter(FPU_KERN_NOCTX)")); 686 if (PCPU_GET(fpcurthread) == td) { 687 printf("fpudna: fpcurthread == curthread\n"); 688 stop_emulating(); 689 critical_exit(); 690 return; 691 } 692 if (PCPU_GET(fpcurthread) != NULL) { 693 panic("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n", 694 PCPU_GET(fpcurthread), PCPU_GET(fpcurthread)->td_tid, 695 td, td->td_tid); 696 } 697 restore_fpu_curthread(td); 698 critical_exit(); 699} 700 701void fpu_activate_sw(struct thread *td); /* Called from the context switch */ 702void 703fpu_activate_sw(struct thread *td) 704{ 705 706 if (lazy_fpu_switch || (td->td_pflags & TDP_KTHREAD) != 0 || 707 !PCB_USER_FPU(td->td_pcb)) { 708 PCPU_SET(fpcurthread, NULL); 709 start_emulating(); 710 } else if (PCPU_GET(fpcurthread) != td) { 711 restore_fpu_curthread(td); 712 } 713} 714 715void 716fpudrop(void) 717{ 718 struct thread *td; 719 720 td = PCPU_GET(fpcurthread); 721 KASSERT(td == curthread, ("fpudrop: fpcurthread != curthread")); 722 CRITICAL_ASSERT(td); 723 PCPU_SET(fpcurthread, NULL); 724 clear_pcb_flags(td->td_pcb, PCB_FPUINITDONE); 725 start_emulating(); 726} 727 728/* 729 * Get the user state of the FPU into pcb->pcb_user_save without 730 * dropping ownership (if possible). It returns the FPU ownership 731 * status. 732 */ 733int 734fpugetregs(struct thread *td) 735{ 736 struct pcb *pcb; 737 uint64_t *xstate_bv, bit; 738 char *sa; 739 int max_ext_n, i, owned; 740 741 pcb = td->td_pcb; 742 if ((pcb->pcb_flags & PCB_USERFPUINITDONE) == 0) { 743 bcopy(fpu_initialstate, get_pcb_user_save_pcb(pcb), 744 cpu_max_ext_state_size); 745 get_pcb_user_save_pcb(pcb)->sv_env.en_cw = 746 pcb->pcb_initial_fpucw; 747 fpuuserinited(td); 748 return (_MC_FPOWNED_PCB); 749 } 750 critical_enter(); 751 if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) { 752 fpusave(get_pcb_user_save_pcb(pcb)); 753 owned = _MC_FPOWNED_FPU; 754 } else { 755 owned = _MC_FPOWNED_PCB; 756 } 757 critical_exit(); 758 if (use_xsave) { 759 /* 760 * Handle partially saved state. 761 */ 762 sa = (char *)get_pcb_user_save_pcb(pcb); 763 xstate_bv = (uint64_t *)(sa + sizeof(struct savefpu) + 764 offsetof(struct xstate_hdr, xstate_bv)); 765 max_ext_n = flsl(xsave_mask); 766 for (i = 0; i < max_ext_n; i++) { 767 bit = 1ULL << i; 768 if ((xsave_mask & bit) == 0 || (*xstate_bv & bit) != 0) 769 continue; 770 bcopy((char *)fpu_initialstate + 771 xsave_area_desc[i].offset, 772 sa + xsave_area_desc[i].offset, 773 xsave_area_desc[i].size); 774 *xstate_bv |= bit; 775 } 776 } 777 return (owned); 778} 779 780void 781fpuuserinited(struct thread *td) 782{ 783 struct pcb *pcb; 784 785 pcb = td->td_pcb; 786 if (PCB_USER_FPU(pcb)) 787 set_pcb_flags(pcb, 788 PCB_FPUINITDONE | PCB_USERFPUINITDONE); 789 else 790 set_pcb_flags(pcb, PCB_FPUINITDONE); 791} 792 793int 794fpusetxstate(struct thread *td, char *xfpustate, size_t xfpustate_size) 795{ 796 struct xstate_hdr *hdr, *ehdr; 797 size_t len, max_len; 798 uint64_t bv; 799 800 /* XXXKIB should we clear all extended state in xstate_bv instead ? */ 801 if (xfpustate == NULL) 802 return (0); 803 if (!use_xsave) 804 return (EOPNOTSUPP); 805 806 len = xfpustate_size; 807 if (len < sizeof(struct xstate_hdr)) 808 return (EINVAL); 809 max_len = cpu_max_ext_state_size - sizeof(struct savefpu); 810 if (len > max_len) 811 return (EINVAL); 812 813 ehdr = (struct xstate_hdr *)xfpustate; 814 bv = ehdr->xstate_bv; 815 816 /* 817 * Avoid #gp. 818 */ 819 if (bv & ~xsave_mask) 820 return (EINVAL); 821 822 hdr = (struct xstate_hdr *)(get_pcb_user_save_td(td) + 1); 823 824 hdr->xstate_bv = bv; 825 bcopy(xfpustate + sizeof(struct xstate_hdr), 826 (char *)(hdr + 1), len - sizeof(struct xstate_hdr)); 827 828 return (0); 829} 830 831/* 832 * Set the state of the FPU. 833 */ 834int 835fpusetregs(struct thread *td, struct savefpu *addr, char *xfpustate, 836 size_t xfpustate_size) 837{ 838 struct pcb *pcb; 839 int error; 840 841 addr->sv_env.en_mxcsr &= cpu_mxcsr_mask; 842 pcb = td->td_pcb; 843 critical_enter(); 844 if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) { 845 error = fpusetxstate(td, xfpustate, xfpustate_size); 846 if (error != 0) { 847 critical_exit(); 848 return (error); 849 } 850 bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr)); 851 fpurestore(get_pcb_user_save_td(td)); 852 critical_exit(); 853 set_pcb_flags(pcb, PCB_FPUINITDONE | PCB_USERFPUINITDONE); 854 } else { 855 critical_exit(); 856 error = fpusetxstate(td, xfpustate, xfpustate_size); 857 if (error != 0) 858 return (error); 859 bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr)); 860 fpuuserinited(td); 861 } 862 return (0); 863} 864 865/* 866 * On AuthenticAMD processors, the fxrstor instruction does not restore 867 * the x87's stored last instruction pointer, last data pointer, and last 868 * opcode values, except in the rare case in which the exception summary 869 * (ES) bit in the x87 status word is set to 1. 870 * 871 * In order to avoid leaking this information across processes, we clean 872 * these values by performing a dummy load before executing fxrstor(). 873 */ 874static void 875fpu_clean_state(void) 876{ 877 static float dummy_variable = 0.0; 878 u_short status; 879 880 /* 881 * Clear the ES bit in the x87 status word if it is currently 882 * set, in order to avoid causing a fault in the upcoming load. 883 */ 884 fnstsw(&status); 885 if (status & 0x80) 886 fnclex(); 887 888 /* 889 * Load the dummy variable into the x87 stack. This mangles 890 * the x87 stack, but we don't care since we're about to call 891 * fxrstor() anyway. 892 */ 893 __asm __volatile("ffree %%st(7); flds %0" : : "m" (dummy_variable)); 894} 895 896/* 897 * This really sucks. We want the acpi version only, but it requires 898 * the isa_if.h file in order to get the definitions. 899 */ 900#include "opt_isa.h" 901#ifdef DEV_ISA 902#include <isa/isavar.h> 903/* 904 * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI. 905 */ 906static struct isa_pnp_id fpupnp_ids[] = { 907 { 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */ 908 { 0 } 909}; 910 911static int 912fpupnp_probe(device_t dev) 913{ 914 int result; 915 916 result = ISA_PNP_PROBE(device_get_parent(dev), dev, fpupnp_ids); 917 if (result <= 0) 918 device_quiet(dev); 919 return (result); 920} 921 922static int 923fpupnp_attach(device_t dev) 924{ 925 926 return (0); 927} 928 929static device_method_t fpupnp_methods[] = { 930 /* Device interface */ 931 DEVMETHOD(device_probe, fpupnp_probe), 932 DEVMETHOD(device_attach, fpupnp_attach), 933 DEVMETHOD(device_detach, bus_generic_detach), 934 DEVMETHOD(device_shutdown, bus_generic_shutdown), 935 DEVMETHOD(device_suspend, bus_generic_suspend), 936 DEVMETHOD(device_resume, bus_generic_resume), 937 938 { 0, 0 } 939}; 940 941static driver_t fpupnp_driver = { 942 "fpupnp", 943 fpupnp_methods, 944 1, /* no softc */ 945}; 946 947static devclass_t fpupnp_devclass; 948 949DRIVER_MODULE(fpupnp, acpi, fpupnp_driver, fpupnp_devclass, 0, 0); 950#endif /* DEV_ISA */ 951 952static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx", 953 "Kernel contexts for FPU state"); 954 955#define FPU_KERN_CTX_FPUINITDONE 0x01 956#define FPU_KERN_CTX_DUMMY 0x02 /* avoided save for the kern thread */ 957#define FPU_KERN_CTX_INUSE 0x04 958 959struct fpu_kern_ctx { 960 struct savefpu *prev; 961 uint32_t flags; 962 char hwstate1[]; 963}; 964 965struct fpu_kern_ctx * 966fpu_kern_alloc_ctx(u_int flags) 967{ 968 struct fpu_kern_ctx *res; 969 size_t sz; 970 971 sz = sizeof(struct fpu_kern_ctx) + XSAVE_AREA_ALIGN + 972 cpu_max_ext_state_size; 973 res = malloc(sz, M_FPUKERN_CTX, ((flags & FPU_KERN_NOWAIT) ? 974 M_NOWAIT : M_WAITOK) | M_ZERO); 975 return (res); 976} 977 978void 979fpu_kern_free_ctx(struct fpu_kern_ctx *ctx) 980{ 981 982 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) == 0, ("free'ing inuse ctx")); 983 /* XXXKIB clear the memory ? */ 984 free(ctx, M_FPUKERN_CTX); 985} 986 987static struct savefpu * 988fpu_kern_ctx_savefpu(struct fpu_kern_ctx *ctx) 989{ 990 vm_offset_t p; 991 992 p = (vm_offset_t)&ctx->hwstate1; 993 p = roundup2(p, XSAVE_AREA_ALIGN); 994 return ((struct savefpu *)p); 995} 996 997int 998fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags) 999{ 1000 struct pcb *pcb; 1001 1002 pcb = td->td_pcb; 1003 KASSERT((flags & FPU_KERN_NOCTX) != 0 || ctx != NULL, 1004 ("ctx is required when !FPU_KERN_NOCTX")); 1005 KASSERT(ctx == NULL || (ctx->flags & FPU_KERN_CTX_INUSE) == 0, 1006 ("using inuse ctx")); 1007 KASSERT((pcb->pcb_flags & PCB_FPUNOSAVE) == 0, 1008 ("recursive fpu_kern_enter while in PCB_FPUNOSAVE state")); 1009 1010 if ((flags & FPU_KERN_NOCTX) != 0) { 1011 critical_enter(); 1012 stop_emulating(); 1013 if (curthread == PCPU_GET(fpcurthread)) { 1014 fpusave(curpcb->pcb_save); 1015 PCPU_SET(fpcurthread, NULL); 1016 } else { 1017 KASSERT(PCPU_GET(fpcurthread) == NULL, 1018 ("invalid fpcurthread")); 1019 } 1020 1021 /* 1022 * This breaks XSAVEOPT tracker, but 1023 * PCB_FPUNOSAVE state is supposed to never need to 1024 * save FPU context at all. 1025 */ 1026 fpurestore(fpu_initialstate); 1027 set_pcb_flags(pcb, PCB_KERNFPU | PCB_FPUNOSAVE | 1028 PCB_FPUINITDONE); 1029 return (0); 1030 } 1031 if ((flags & FPU_KERN_KTHR) != 0 && is_fpu_kern_thread(0)) { 1032 ctx->flags = FPU_KERN_CTX_DUMMY | FPU_KERN_CTX_INUSE; 1033 return (0); 1034 } 1035 KASSERT(!PCB_USER_FPU(pcb) || pcb->pcb_save == 1036 get_pcb_user_save_pcb(pcb), ("mangled pcb_save")); 1037 ctx->flags = FPU_KERN_CTX_INUSE; 1038 if ((pcb->pcb_flags & PCB_FPUINITDONE) != 0) 1039 ctx->flags |= FPU_KERN_CTX_FPUINITDONE; 1040 fpuexit(td); 1041 ctx->prev = pcb->pcb_save; 1042 pcb->pcb_save = fpu_kern_ctx_savefpu(ctx); 1043 set_pcb_flags(pcb, PCB_KERNFPU); 1044 clear_pcb_flags(pcb, PCB_FPUINITDONE); 1045 return (0); 1046} 1047 1048int 1049fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx) 1050{ 1051 struct pcb *pcb; 1052 1053 pcb = td->td_pcb; 1054 1055 if ((pcb->pcb_flags & PCB_FPUNOSAVE) != 0) { 1056 KASSERT(ctx == NULL, ("non-null ctx after FPU_KERN_NOCTX")); 1057 KASSERT(PCPU_GET(fpcurthread) == NULL, 1058 ("non-NULL fpcurthread for PCB_FPUNOSAVE")); 1059 CRITICAL_ASSERT(td); 1060 1061 clear_pcb_flags(pcb, PCB_FPUNOSAVE | PCB_FPUINITDONE); 1062 start_emulating(); 1063 critical_exit(); 1064 } else { 1065 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) != 0, 1066 ("leaving not inuse ctx")); 1067 ctx->flags &= ~FPU_KERN_CTX_INUSE; 1068 1069 if (is_fpu_kern_thread(0) && 1070 (ctx->flags & FPU_KERN_CTX_DUMMY) != 0) 1071 return (0); 1072 KASSERT((ctx->flags & FPU_KERN_CTX_DUMMY) == 0, 1073 ("dummy ctx")); 1074 critical_enter(); 1075 if (curthread == PCPU_GET(fpcurthread)) 1076 fpudrop(); 1077 critical_exit(); 1078 pcb->pcb_save = ctx->prev; 1079 } 1080 1081 if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) { 1082 if ((pcb->pcb_flags & PCB_USERFPUINITDONE) != 0) { 1083 set_pcb_flags(pcb, PCB_FPUINITDONE); 1084 clear_pcb_flags(pcb, PCB_KERNFPU); 1085 } else 1086 clear_pcb_flags(pcb, PCB_FPUINITDONE | PCB_KERNFPU); 1087 } else { 1088 if ((ctx->flags & FPU_KERN_CTX_FPUINITDONE) != 0) 1089 set_pcb_flags(pcb, PCB_FPUINITDONE); 1090 else 1091 clear_pcb_flags(pcb, PCB_FPUINITDONE); 1092 KASSERT(!PCB_USER_FPU(pcb), ("unpaired fpu_kern_leave")); 1093 } 1094 return (0); 1095} 1096 1097int 1098fpu_kern_thread(u_int flags) 1099{ 1100 1101 KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0, 1102 ("Only kthread may use fpu_kern_thread")); 1103 KASSERT(curpcb->pcb_save == get_pcb_user_save_pcb(curpcb), 1104 ("mangled pcb_save")); 1105 KASSERT(PCB_USER_FPU(curpcb), ("recursive call")); 1106 1107 set_pcb_flags(curpcb, PCB_KERNFPU); 1108 return (0); 1109} 1110 1111int 1112is_fpu_kern_thread(u_int flags) 1113{ 1114 1115 if ((curthread->td_pflags & TDP_KTHREAD) == 0) 1116 return (0); 1117 return ((curpcb->pcb_flags & PCB_KERNFPU) != 0); 1118} 1119 1120/* 1121 * FPU save area alloc/free/init utility routines 1122 */ 1123struct savefpu * 1124fpu_save_area_alloc(void) 1125{ 1126 1127 return (uma_zalloc(fpu_save_area_zone, 0)); 1128} 1129 1130void 1131fpu_save_area_free(struct savefpu *fsa) 1132{ 1133 1134 uma_zfree(fpu_save_area_zone, fsa); 1135} 1136 1137void 1138fpu_save_area_reset(struct savefpu *fsa) 1139{ 1140 1141 bcopy(fpu_initialstate, fsa, cpu_max_ext_state_size); 1142} 1143