fpu.c revision 83640
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 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)npx.c 7.2 (Berkeley) 5/12/91 35 * $FreeBSD: head/sys/amd64/amd64/fpu.c 83640 2001-09-18 21:05:04Z jhb $ 36 */ 37 38#include "opt_cpu.h" 39#include "opt_debug_npx.h" 40#include "opt_math_emulate.h" 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/bus.h> 45#include <sys/kernel.h> 46#include <sys/lock.h> 47#include <sys/malloc.h> 48#include <sys/module.h> 49#include <sys/mutex.h> 50#include <sys/mutex.h> 51#include <sys/proc.h> 52#include <sys/sysctl.h> 53#include <machine/bus.h> 54#include <sys/rman.h> 55#ifdef NPX_DEBUG 56#include <sys/syslog.h> 57#endif 58#include <sys/signalvar.h> 59#include <sys/user.h> 60 61#ifndef SMP 62#include <machine/asmacros.h> 63#endif 64#include <machine/cputypes.h> 65#include <machine/frame.h> 66#include <machine/md_var.h> 67#include <machine/pcb.h> 68#include <machine/psl.h> 69#ifndef SMP 70#include <machine/clock.h> 71#endif 72#include <machine/resource.h> 73#include <machine/specialreg.h> 74#include <machine/segments.h> 75 76#ifndef SMP 77#include <i386/isa/icu.h> 78#include <i386/isa/intr_machdep.h> 79#include <i386/isa/isa.h> 80#endif 81#include <isa/isavar.h> 82 83/* 84 * 387 and 287 Numeric Coprocessor Extension (NPX) Driver. 85 */ 86 87/* Configuration flags. */ 88#define NPX_DISABLE_I586_OPTIMIZED_BCOPY (1 << 0) 89#define NPX_DISABLE_I586_OPTIMIZED_BZERO (1 << 1) 90#define NPX_DISABLE_I586_OPTIMIZED_COPYIO (1 << 2) 91#define NPX_PREFER_EMULATOR (1 << 3) 92 93#ifdef __GNUC__ 94 95#define fldcw(addr) __asm("fldcw %0" : : "m" (*(addr))) 96#define fnclex() __asm("fnclex") 97#define fninit() __asm("fninit") 98#define fnsave(addr) __asm __volatile("fnsave %0" : "=m" (*(addr))) 99#define fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 100#define fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 101#define fp_divide_by_0() __asm("fldz; fld1; fdiv %st,%st(1); fnop") 102#define frstor(addr) __asm("frstor %0" : : "m" (*(addr))) 103#ifdef CPU_ENABLE_SSE 104#define fxrstor(addr) __asm("fxrstor %0" : : "m" (*(addr))) 105#define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr))) 106#endif 107#define start_emulating() __asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \ 108 : : "n" (CR0_TS) : "ax") 109#define stop_emulating() __asm("clts") 110 111#else /* not __GNUC__ */ 112 113void fldcw __P((caddr_t addr)); 114void fnclex __P((void)); 115void fninit __P((void)); 116void fnsave __P((caddr_t addr)); 117void fnstcw __P((caddr_t addr)); 118void fnstsw __P((caddr_t addr)); 119void fp_divide_by_0 __P((void)); 120void frstor __P((caddr_t addr)); 121#ifdef CPU_ENABLE_SSE 122void fxsave __P((caddr_t addr)); 123void fxrstor __P((caddr_t addr)); 124#endif 125void start_emulating __P((void)); 126void stop_emulating __P((void)); 127 128#endif /* __GNUC__ */ 129 130#ifdef CPU_ENABLE_SSE 131#define GET_FPU_CW(thread) \ 132 (cpu_fxsr ? \ 133 (thread)->td_pcb->pcb_save.sv_xmm.sv_env.en_cw : \ 134 (thread)->td_pcb->pcb_save.sv_87.sv_env.en_cw) 135#define GET_FPU_SW(thread) \ 136 (cpu_fxsr ? \ 137 (thread)->td_pcb->pcb_save.sv_xmm.sv_env.en_sw : \ 138 (thread)->td_pcb->pcb_save.sv_87.sv_env.en_sw) 139#define GET_FPU_EXSW_PTR(pcb) \ 140 (cpu_fxsr ? \ 141 &(pcb)->pcb_save.sv_xmm.sv_ex_sw : \ 142 &(pcb)->pcb_save.sv_87.sv_ex_sw) 143#else /* CPU_ENABLE_SSE */ 144#define GET_FPU_CW(thread) \ 145 (thread->td_pcb->pcb_save.sv_87.sv_env.en_cw) 146#define GET_FPU_SW(thread) \ 147 (thread->td_pcb->pcb_save.sv_87.sv_env.en_sw) 148#define GET_FPU_EXSW_PTR(pcb) \ 149 (&(pcb)->pcb_save.sv_87.sv_ex_sw) 150#endif /* CPU_ENABLE_SSE */ 151 152typedef u_char bool_t; 153 154static int npx_attach __P((device_t dev)); 155static void npx_identify __P((driver_t *driver, device_t parent)); 156#ifndef SMP 157static void npx_intr __P((void *)); 158#endif 159static int npx_probe __P((device_t dev)); 160static int npx_probe1 __P((device_t dev)); 161static void fpusave __P((union savefpu *)); 162static void fpurstor __P((union savefpu *)); 163#ifdef I586_CPU_XXX 164static long timezero __P((const char *funcname, 165 void (*func)(void *buf, size_t len))); 166#endif /* I586_CPU */ 167 168int hw_float; /* XXX currently just alias for npx_exists */ 169 170SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint, 171 CTLFLAG_RD, &hw_float, 0, 172 "Floatingpoint instructions executed in hardware"); 173 174#ifndef SMP 175static volatile u_int npx_intrs_while_probing; 176static volatile u_int npx_traps_while_probing; 177#endif 178 179static bool_t npx_ex16; 180static bool_t npx_exists; 181static bool_t npx_irq13; 182static int npx_irq; /* irq number */ 183 184#ifndef SMP 185/* 186 * Special interrupt handlers. Someday intr0-intr15 will be used to count 187 * interrupts. We'll still need a special exception 16 handler. The busy 188 * latch stuff in probeintr() can be moved to npxprobe(). 189 */ 190inthand_t probeintr; 191__asm(" \n\ 192 .text \n\ 193 .p2align 2,0x90 \n\ 194 .type " __XSTRING(CNAME(probeintr)) ",@function \n\ 195" __XSTRING(CNAME(probeintr)) ": \n\ 196 ss \n\ 197 incl " __XSTRING(CNAME(npx_intrs_while_probing)) " \n\ 198 pushl %eax \n\ 199 movb $0x20,%al # EOI (asm in strings loses cpp features) \n\ 200 outb %al,$0xa0 # IO_ICU2 \n\ 201 outb %al,$0x20 # IO_ICU1 \n\ 202 movb $0,%al \n\ 203 outb %al,$0xf0 # clear BUSY# latch \n\ 204 popl %eax \n\ 205 iret \n\ 206"); 207 208inthand_t probetrap; 209__asm(" \n\ 210 .text \n\ 211 .p2align 2,0x90 \n\ 212 .type " __XSTRING(CNAME(probetrap)) ",@function \n\ 213" __XSTRING(CNAME(probetrap)) ": \n\ 214 ss \n\ 215 incl " __XSTRING(CNAME(npx_traps_while_probing)) " \n\ 216 fnclex \n\ 217 iret \n\ 218"); 219#endif /* SMP */ 220 221/* 222 * Identify routine. Create a connection point on our parent for probing. 223 */ 224static void 225npx_identify(driver, parent) 226 driver_t *driver; 227 device_t parent; 228{ 229 device_t child; 230 231 child = BUS_ADD_CHILD(parent, 0, "npx", 0); 232 if (child == NULL) 233 panic("npx_identify"); 234} 235 236#ifndef SMP 237/* 238 * Do minimal handling of npx interrupts to convert them to traps. 239 */ 240static void 241npx_intr(dummy) 242 void *dummy; 243{ 244 struct thread *td; 245 246 /* 247 * The BUSY# latch must be cleared in all cases so that the next 248 * unmasked npx exception causes an interrupt. 249 */ 250 outb(0xf0, 0); 251 252 /* 253 * npxthread is normally non-null here. In that case, schedule an 254 * AST to finish the exception handling in the correct context 255 * (this interrupt may occur after the thread has entered the 256 * kernel via a syscall or an interrupt). Otherwise, the npx 257 * state of the thread that caused this interrupt must have been 258 * pushed to the thread's pcb, and clearing of the busy latch 259 * above has finished the (essentially null) handling of this 260 * interrupt. Control will eventually return to the instruction 261 * that caused it and it will repeat. We will eventually (usually 262 * soon) win the race to handle the interrupt properly. 263 */ 264 td = PCPU_GET(npxthread); 265 if (td != NULL) { 266 td->td_pcb->pcb_flags |= PCB_NPXTRAP; 267 mtx_lock_spin(&sched_lock); 268 td->td_kse->ke_flags |= KEF_ASTPENDING; 269 mtx_unlock_spin(&sched_lock); 270 } 271} 272 273/* 274 * XXX these "local" variables of npx_probe() are non-local so that 275 * npxprobe1() can abuse them. 276 */ 277static int npx_intrno; 278static struct gate_descriptor save_idt_npxintr; 279#endif /* !SMP */ 280 281/* 282 * Probe routine. Initialize cr0 to give correct behaviour for [f]wait 283 * whether the device exists or not (XXX should be elsewhere). Set flags 284 * to tell npxattach() what to do. Modify device struct if npx doesn't 285 * need to use interrupts. Return 1 if device exists. 286 */ 287static int 288npx_probe(dev) 289 device_t dev; 290{ 291#ifdef SMP 292 293 if (resource_int_value("npx", 0, "irq", &npx_irq) != 0) 294 npx_irq = 13; 295 return npx_probe1(dev); 296 297#else /* SMP */ 298 299 int result; 300 critical_t savecrit; 301 u_char save_icu1_mask; 302 u_char save_icu2_mask; 303 struct gate_descriptor save_idt_npxtrap; 304 /* 305 * This routine is now just a wrapper for npxprobe1(), to install 306 * special npx interrupt and trap handlers, to enable npx interrupts 307 * and to disable other interrupts. Someday isa_configure() will 308 * install suitable handlers and run with interrupts enabled so we 309 * won't need to do so much here. 310 */ 311 if (resource_int_value("npx", 0, "irq", &npx_irq) != 0) 312 npx_irq = 13; 313 npx_intrno = NRSVIDT + npx_irq; 314 savecrit = critical_enter(); 315 save_icu1_mask = inb(IO_ICU1 + 1); 316 save_icu2_mask = inb(IO_ICU2 + 1); 317 save_idt_npxintr = idt[npx_intrno]; 318 save_idt_npxtrap = idt[16]; 319 outb(IO_ICU1 + 1, ~IRQ_SLAVE); 320 outb(IO_ICU2 + 1, ~(1 << (npx_irq - 8))); 321 setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL)); 322 setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL)); 323 324 /* 325 * XXX This looks highly bogus, but it appears that npc_probe1 326 * needs interrupts enabled. Does this make any difference 327 * here? 328 */ 329 critical_exit(savecrit); 330 result = npx_probe1(dev); 331 savecrit = critical_enter(); 332 outb(IO_ICU1 + 1, save_icu1_mask); 333 outb(IO_ICU2 + 1, save_icu2_mask); 334 idt[npx_intrno] = save_idt_npxintr; 335 idt[16] = save_idt_npxtrap; 336 critical_exit(savecrit); 337 return (result); 338 339#endif /* SMP */ 340} 341 342static int 343npx_probe1(dev) 344 device_t dev; 345{ 346#ifndef SMP 347 u_short control; 348 u_short status; 349#endif 350 351 /* 352 * Partially reset the coprocessor, if any. Some BIOS's don't reset 353 * it after a warm boot. 354 */ 355 outb(0xf1, 0); /* full reset on some systems, NOP on others */ 356 outb(0xf0, 0); /* clear BUSY# latch */ 357 /* 358 * Prepare to trap all ESC (i.e., NPX) instructions and all WAIT 359 * instructions. We must set the CR0_MP bit and use the CR0_TS 360 * bit to control the trap, because setting the CR0_EM bit does 361 * not cause WAIT instructions to trap. It's important to trap 362 * WAIT instructions - otherwise the "wait" variants of no-wait 363 * control instructions would degenerate to the "no-wait" variants 364 * after FP context switches but work correctly otherwise. It's 365 * particularly important to trap WAITs when there is no NPX - 366 * otherwise the "wait" variants would always degenerate. 367 * 368 * Try setting CR0_NE to get correct error reporting on 486DX's. 369 * Setting it should fail or do nothing on lesser processors. 370 */ 371 load_cr0(rcr0() | CR0_MP | CR0_NE); 372 /* 373 * But don't trap while we're probing. 374 */ 375 stop_emulating(); 376 /* 377 * Finish resetting the coprocessor, if any. If there is an error 378 * pending, then we may get a bogus IRQ13, but probeintr() will handle 379 * it OK. Bogus halts have never been observed, but we enabled 380 * IRQ13 and cleared the BUSY# latch early to handle them anyway. 381 */ 382 fninit(); 383 384#ifdef SMP 385 /* 386 * Exception 16 MUST work for SMP. 387 */ 388 npx_irq13 = 0; 389 npx_ex16 = hw_float = npx_exists = 1; 390 device_set_desc(dev, "math processor"); 391 return (0); 392 393#else /* !SMP */ 394 device_set_desc(dev, "math processor"); 395 396 /* 397 * Don't use fwait here because it might hang. 398 * Don't use fnop here because it usually hangs if there is no FPU. 399 */ 400 DELAY(1000); /* wait for any IRQ13 */ 401#ifdef DIAGNOSTIC 402 if (npx_intrs_while_probing != 0) 403 printf("fninit caused %u bogus npx interrupt(s)\n", 404 npx_intrs_while_probing); 405 if (npx_traps_while_probing != 0) 406 printf("fninit caused %u bogus npx trap(s)\n", 407 npx_traps_while_probing); 408#endif 409 /* 410 * Check for a status of mostly zero. 411 */ 412 status = 0x5a5a; 413 fnstsw(&status); 414 if ((status & 0xb8ff) == 0) { 415 /* 416 * Good, now check for a proper control word. 417 */ 418 control = 0x5a5a; 419 fnstcw(&control); 420 if ((control & 0x1f3f) == 0x033f) { 421 hw_float = npx_exists = 1; 422 /* 423 * We have an npx, now divide by 0 to see if exception 424 * 16 works. 425 */ 426 control &= ~(1 << 2); /* enable divide by 0 trap */ 427 fldcw(&control); 428 npx_traps_while_probing = npx_intrs_while_probing = 0; 429 fp_divide_by_0(); 430 if (npx_traps_while_probing != 0) { 431 /* 432 * Good, exception 16 works. 433 */ 434 npx_ex16 = 1; 435 return (0); 436 } 437 if (npx_intrs_while_probing != 0) { 438 int rid; 439 struct resource *r; 440 void *intr; 441 /* 442 * Bad, we are stuck with IRQ13. 443 */ 444 npx_irq13 = 1; 445 446 /* 447 * We allocate these resources permanently, 448 * so there is no need to keep track of them. 449 */ 450 rid = 0; 451 r = bus_alloc_resource(dev, SYS_RES_IOPORT, 452 &rid, IO_NPX, IO_NPX, 453 IO_NPXSIZE, RF_ACTIVE); 454 if (r == 0) 455 panic("npx: can't get ports"); 456 rid = 0; 457 r = bus_alloc_resource(dev, SYS_RES_IRQ, 458 &rid, npx_irq, npx_irq, 459 1, RF_ACTIVE); 460 if (r == 0) 461 panic("npx: can't get IRQ"); 462 BUS_SETUP_INTR(device_get_parent(dev), 463 dev, r, 464 INTR_TYPE_MISC | INTR_FAST, 465 npx_intr, 0, &intr); 466 if (intr == 0) 467 panic("npx: can't create intr"); 468 469 /* 470 * XXX BUS_SETUP_INTR() has changed 471 * idt[npx_intrno] to point to Xfastintr0 472 * instead of Xfastintr0. Adjust 473 * save_idt_npxintr so that npxprobe() 474 * doesn't undo this. 475 */ 476 save_idt_npxintr = idt[npx_intrno]; 477 478 return (0); 479 } 480 /* 481 * Worse, even IRQ13 is broken. Use emulator. 482 */ 483 } 484 } 485 /* 486 * Probe failed, but we want to get to npxattach to initialize the 487 * emulator and say that it has been installed. XXX handle devices 488 * that aren't really devices better. 489 */ 490 return (0); 491#endif /* SMP */ 492} 493 494/* 495 * Attach routine - announce which it is, and wire into system 496 */ 497int 498npx_attach(dev) 499 device_t dev; 500{ 501 int flags; 502 503 if (resource_int_value("npx", 0, "flags", &flags) != 0) 504 flags = 0; 505 506 if (flags) 507 device_printf(dev, "flags 0x%x ", flags); 508 if (npx_irq13) { 509 device_printf(dev, "using IRQ 13 interface\n"); 510 } else { 511#if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE) 512 if (npx_ex16) { 513 if (!(flags & NPX_PREFER_EMULATOR)) 514 device_printf(dev, "INT 16 interface\n"); 515 else { 516 device_printf(dev, "FPU exists, but flags request " 517 "emulator\n"); 518 hw_float = npx_exists = 0; 519 } 520 } else if (npx_exists) { 521 device_printf(dev, "error reporting broken; using 387 emulator\n"); 522 hw_float = npx_exists = 0; 523 } else 524 device_printf(dev, "387 emulator\n"); 525#else 526 if (npx_ex16) { 527 device_printf(dev, "INT 16 interface\n"); 528 if (flags & NPX_PREFER_EMULATOR) { 529 device_printf(dev, "emulator requested, but none compiled " 530 "into kernel, using FPU\n"); 531 } 532 } else 533 device_printf(dev, "no 387 emulator in kernel and no FPU!\n"); 534#endif 535 } 536 npxinit(__INITIAL_NPXCW__); 537 538#ifdef I586_CPU_XXX 539 if (cpu_class == CPUCLASS_586 && npx_ex16 && npx_exists && 540 timezero("i586_bzero()", i586_bzero) < 541 timezero("bzero()", bzero) * 4 / 5) { 542 if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) { 543 bcopy_vector = i586_bcopy; 544 ovbcopy_vector = i586_bcopy; 545 } 546 if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BZERO)) 547 bzero = i586_bzero; 548 if (!(flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) { 549 copyin_vector = i586_copyin; 550 copyout_vector = i586_copyout; 551 } 552 } 553#endif 554 555 return (0); /* XXX unused */ 556} 557 558/* 559 * Initialize floating point unit. 560 */ 561void 562npxinit(control) 563 u_short control; 564{ 565 static union savefpu dummy; 566 critical_t savecrit; 567 568 if (!npx_exists) 569 return; 570 /* 571 * fninit has the same h/w bugs as fnsave. Use the detoxified 572 * fnsave to throw away any junk in the fpu. npxsave() initializes 573 * the fpu and sets npxthread = NULL as important side effects. 574 */ 575 savecrit = critical_enter(); 576 npxsave(&dummy); 577 stop_emulating(); 578 fldcw(&control); 579 if (PCPU_GET(curpcb) != NULL) 580 fpusave(&PCPU_GET(curpcb)->pcb_save); 581 start_emulating(); 582 critical_exit(savecrit); 583} 584 585/* 586 * Free coprocessor (if we have it). 587 */ 588void 589npxexit(td) 590 struct thread *td; 591{ 592 critical_t savecrit; 593 594 savecrit = critical_enter(); 595 if (td == PCPU_GET(npxthread)) 596 npxsave(&PCPU_GET(curpcb)->pcb_save); 597 critical_exit(savecrit); 598#ifdef NPX_DEBUG 599 if (npx_exists) { 600 u_int masked_exceptions; 601 602 masked_exceptions = PCPU_GET(curpcb)->pcb_save.sv_87.sv_env.en_cw 603 & PCPU_GET(curpcb)->pcb_save.sv_87.sv_env.en_sw & 0x7f; 604 /* 605 * Log exceptions that would have trapped with the old 606 * control word (overflow, divide by 0, and invalid operand). 607 */ 608 if (masked_exceptions & 0x0d) 609 log(LOG_ERR, 610 "pid %d (%s) exited with masked floating point exceptions 0x%02x\n", 611 td->td_proc->p_pid, td->td_proc->p_comm, 612 masked_exceptions); 613 } 614#endif 615} 616 617/* 618 * The following mechanism is used to ensure that the FPE_... value 619 * that is passed as a trapcode to the signal handler of the user 620 * process does not have more than one bit set. 621 * 622 * Multiple bits may be set if the user process modifies the control 623 * word while a status word bit is already set. While this is a sign 624 * of bad coding, we have no choise than to narrow them down to one 625 * bit, since we must not send a trapcode that is not exactly one of 626 * the FPE_ macros. 627 * 628 * The mechanism has a static table with 127 entries. Each combination 629 * of the 7 FPU status word exception bits directly translates to a 630 * position in this table, where a single FPE_... value is stored. 631 * This FPE_... value stored there is considered the "most important" 632 * of the exception bits and will be sent as the signal code. The 633 * precedence of the bits is based upon Intel Document "Numerical 634 * Applications", Chapter "Special Computational Situations". 635 * 636 * The macro to choose one of these values does these steps: 1) Throw 637 * away status word bits that cannot be masked. 2) Throw away the bits 638 * currently masked in the control word, assuming the user isn't 639 * interested in them anymore. 3) Reinsert status word bit 7 (stack 640 * fault) if it is set, which cannot be masked but must be presered. 641 * 4) Use the remaining bits to point into the trapcode table. 642 * 643 * The 6 maskable bits in order of their preference, as stated in the 644 * above referenced Intel manual: 645 * 1 Invalid operation (FP_X_INV) 646 * 1a Stack underflow 647 * 1b Stack overflow 648 * 1c Operand of unsupported format 649 * 1d SNaN operand. 650 * 2 QNaN operand (not an exception, irrelavant here) 651 * 3 Any other invalid-operation not mentioned above or zero divide 652 * (FP_X_INV, FP_X_DZ) 653 * 4 Denormal operand (FP_X_DNML) 654 * 5 Numeric over/underflow (FP_X_OFL, FP_X_UFL) 655 * 6 Inexact result (FP_X_IMP) 656 */ 657static char fpetable[128] = { 658 0, 659 FPE_FLTINV, /* 1 - INV */ 660 FPE_FLTUND, /* 2 - DNML */ 661 FPE_FLTINV, /* 3 - INV | DNML */ 662 FPE_FLTDIV, /* 4 - DZ */ 663 FPE_FLTINV, /* 5 - INV | DZ */ 664 FPE_FLTDIV, /* 6 - DNML | DZ */ 665 FPE_FLTINV, /* 7 - INV | DNML | DZ */ 666 FPE_FLTOVF, /* 8 - OFL */ 667 FPE_FLTINV, /* 9 - INV | OFL */ 668 FPE_FLTUND, /* A - DNML | OFL */ 669 FPE_FLTINV, /* B - INV | DNML | OFL */ 670 FPE_FLTDIV, /* C - DZ | OFL */ 671 FPE_FLTINV, /* D - INV | DZ | OFL */ 672 FPE_FLTDIV, /* E - DNML | DZ | OFL */ 673 FPE_FLTINV, /* F - INV | DNML | DZ | OFL */ 674 FPE_FLTUND, /* 10 - UFL */ 675 FPE_FLTINV, /* 11 - INV | UFL */ 676 FPE_FLTUND, /* 12 - DNML | UFL */ 677 FPE_FLTINV, /* 13 - INV | DNML | UFL */ 678 FPE_FLTDIV, /* 14 - DZ | UFL */ 679 FPE_FLTINV, /* 15 - INV | DZ | UFL */ 680 FPE_FLTDIV, /* 16 - DNML | DZ | UFL */ 681 FPE_FLTINV, /* 17 - INV | DNML | DZ | UFL */ 682 FPE_FLTOVF, /* 18 - OFL | UFL */ 683 FPE_FLTINV, /* 19 - INV | OFL | UFL */ 684 FPE_FLTUND, /* 1A - DNML | OFL | UFL */ 685 FPE_FLTINV, /* 1B - INV | DNML | OFL | UFL */ 686 FPE_FLTDIV, /* 1C - DZ | OFL | UFL */ 687 FPE_FLTINV, /* 1D - INV | DZ | OFL | UFL */ 688 FPE_FLTDIV, /* 1E - DNML | DZ | OFL | UFL */ 689 FPE_FLTINV, /* 1F - INV | DNML | DZ | OFL | UFL */ 690 FPE_FLTRES, /* 20 - IMP */ 691 FPE_FLTINV, /* 21 - INV | IMP */ 692 FPE_FLTUND, /* 22 - DNML | IMP */ 693 FPE_FLTINV, /* 23 - INV | DNML | IMP */ 694 FPE_FLTDIV, /* 24 - DZ | IMP */ 695 FPE_FLTINV, /* 25 - INV | DZ | IMP */ 696 FPE_FLTDIV, /* 26 - DNML | DZ | IMP */ 697 FPE_FLTINV, /* 27 - INV | DNML | DZ | IMP */ 698 FPE_FLTOVF, /* 28 - OFL | IMP */ 699 FPE_FLTINV, /* 29 - INV | OFL | IMP */ 700 FPE_FLTUND, /* 2A - DNML | OFL | IMP */ 701 FPE_FLTINV, /* 2B - INV | DNML | OFL | IMP */ 702 FPE_FLTDIV, /* 2C - DZ | OFL | IMP */ 703 FPE_FLTINV, /* 2D - INV | DZ | OFL | IMP */ 704 FPE_FLTDIV, /* 2E - DNML | DZ | OFL | IMP */ 705 FPE_FLTINV, /* 2F - INV | DNML | DZ | OFL | IMP */ 706 FPE_FLTUND, /* 30 - UFL | IMP */ 707 FPE_FLTINV, /* 31 - INV | UFL | IMP */ 708 FPE_FLTUND, /* 32 - DNML | UFL | IMP */ 709 FPE_FLTINV, /* 33 - INV | DNML | UFL | IMP */ 710 FPE_FLTDIV, /* 34 - DZ | UFL | IMP */ 711 FPE_FLTINV, /* 35 - INV | DZ | UFL | IMP */ 712 FPE_FLTDIV, /* 36 - DNML | DZ | UFL | IMP */ 713 FPE_FLTINV, /* 37 - INV | DNML | DZ | UFL | IMP */ 714 FPE_FLTOVF, /* 38 - OFL | UFL | IMP */ 715 FPE_FLTINV, /* 39 - INV | OFL | UFL | IMP */ 716 FPE_FLTUND, /* 3A - DNML | OFL | UFL | IMP */ 717 FPE_FLTINV, /* 3B - INV | DNML | OFL | UFL | IMP */ 718 FPE_FLTDIV, /* 3C - DZ | OFL | UFL | IMP */ 719 FPE_FLTINV, /* 3D - INV | DZ | OFL | UFL | IMP */ 720 FPE_FLTDIV, /* 3E - DNML | DZ | OFL | UFL | IMP */ 721 FPE_FLTINV, /* 3F - INV | DNML | DZ | OFL | UFL | IMP */ 722 FPE_FLTSUB, /* 40 - STK */ 723 FPE_FLTSUB, /* 41 - INV | STK */ 724 FPE_FLTUND, /* 42 - DNML | STK */ 725 FPE_FLTSUB, /* 43 - INV | DNML | STK */ 726 FPE_FLTDIV, /* 44 - DZ | STK */ 727 FPE_FLTSUB, /* 45 - INV | DZ | STK */ 728 FPE_FLTDIV, /* 46 - DNML | DZ | STK */ 729 FPE_FLTSUB, /* 47 - INV | DNML | DZ | STK */ 730 FPE_FLTOVF, /* 48 - OFL | STK */ 731 FPE_FLTSUB, /* 49 - INV | OFL | STK */ 732 FPE_FLTUND, /* 4A - DNML | OFL | STK */ 733 FPE_FLTSUB, /* 4B - INV | DNML | OFL | STK */ 734 FPE_FLTDIV, /* 4C - DZ | OFL | STK */ 735 FPE_FLTSUB, /* 4D - INV | DZ | OFL | STK */ 736 FPE_FLTDIV, /* 4E - DNML | DZ | OFL | STK */ 737 FPE_FLTSUB, /* 4F - INV | DNML | DZ | OFL | STK */ 738 FPE_FLTUND, /* 50 - UFL | STK */ 739 FPE_FLTSUB, /* 51 - INV | UFL | STK */ 740 FPE_FLTUND, /* 52 - DNML | UFL | STK */ 741 FPE_FLTSUB, /* 53 - INV | DNML | UFL | STK */ 742 FPE_FLTDIV, /* 54 - DZ | UFL | STK */ 743 FPE_FLTSUB, /* 55 - INV | DZ | UFL | STK */ 744 FPE_FLTDIV, /* 56 - DNML | DZ | UFL | STK */ 745 FPE_FLTSUB, /* 57 - INV | DNML | DZ | UFL | STK */ 746 FPE_FLTOVF, /* 58 - OFL | UFL | STK */ 747 FPE_FLTSUB, /* 59 - INV | OFL | UFL | STK */ 748 FPE_FLTUND, /* 5A - DNML | OFL | UFL | STK */ 749 FPE_FLTSUB, /* 5B - INV | DNML | OFL | UFL | STK */ 750 FPE_FLTDIV, /* 5C - DZ | OFL | UFL | STK */ 751 FPE_FLTSUB, /* 5D - INV | DZ | OFL | UFL | STK */ 752 FPE_FLTDIV, /* 5E - DNML | DZ | OFL | UFL | STK */ 753 FPE_FLTSUB, /* 5F - INV | DNML | DZ | OFL | UFL | STK */ 754 FPE_FLTRES, /* 60 - IMP | STK */ 755 FPE_FLTSUB, /* 61 - INV | IMP | STK */ 756 FPE_FLTUND, /* 62 - DNML | IMP | STK */ 757 FPE_FLTSUB, /* 63 - INV | DNML | IMP | STK */ 758 FPE_FLTDIV, /* 64 - DZ | IMP | STK */ 759 FPE_FLTSUB, /* 65 - INV | DZ | IMP | STK */ 760 FPE_FLTDIV, /* 66 - DNML | DZ | IMP | STK */ 761 FPE_FLTSUB, /* 67 - INV | DNML | DZ | IMP | STK */ 762 FPE_FLTOVF, /* 68 - OFL | IMP | STK */ 763 FPE_FLTSUB, /* 69 - INV | OFL | IMP | STK */ 764 FPE_FLTUND, /* 6A - DNML | OFL | IMP | STK */ 765 FPE_FLTSUB, /* 6B - INV | DNML | OFL | IMP | STK */ 766 FPE_FLTDIV, /* 6C - DZ | OFL | IMP | STK */ 767 FPE_FLTSUB, /* 6D - INV | DZ | OFL | IMP | STK */ 768 FPE_FLTDIV, /* 6E - DNML | DZ | OFL | IMP | STK */ 769 FPE_FLTSUB, /* 6F - INV | DNML | DZ | OFL | IMP | STK */ 770 FPE_FLTUND, /* 70 - UFL | IMP | STK */ 771 FPE_FLTSUB, /* 71 - INV | UFL | IMP | STK */ 772 FPE_FLTUND, /* 72 - DNML | UFL | IMP | STK */ 773 FPE_FLTSUB, /* 73 - INV | DNML | UFL | IMP | STK */ 774 FPE_FLTDIV, /* 74 - DZ | UFL | IMP | STK */ 775 FPE_FLTSUB, /* 75 - INV | DZ | UFL | IMP | STK */ 776 FPE_FLTDIV, /* 76 - DNML | DZ | UFL | IMP | STK */ 777 FPE_FLTSUB, /* 77 - INV | DNML | DZ | UFL | IMP | STK */ 778 FPE_FLTOVF, /* 78 - OFL | UFL | IMP | STK */ 779 FPE_FLTSUB, /* 79 - INV | OFL | UFL | IMP | STK */ 780 FPE_FLTUND, /* 7A - DNML | OFL | UFL | IMP | STK */ 781 FPE_FLTSUB, /* 7B - INV | DNML | OFL | UFL | IMP | STK */ 782 FPE_FLTDIV, /* 7C - DZ | OFL | UFL | IMP | STK */ 783 FPE_FLTSUB, /* 7D - INV | DZ | OFL | UFL | IMP | STK */ 784 FPE_FLTDIV, /* 7E - DNML | DZ | OFL | UFL | IMP | STK */ 785 FPE_FLTSUB, /* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */ 786}; 787 788/* 789 * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE. 790 * 791 * Clearing exceptions is necessary mainly to avoid IRQ13 bugs. We now 792 * depend on longjmp() restoring a usable state. Restoring the state 793 * or examining it might fail if we didn't clear exceptions. 794 * 795 * The error code chosen will be one of the FPE_... macros. It will be 796 * sent as the second argument to old BSD-style signal handlers and as 797 * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers. 798 * 799 * XXX the FP state is not preserved across signal handlers. So signal 800 * handlers cannot afford to do FP unless they preserve the state or 801 * longjmp() out. Both preserving the state and longjmp()ing may be 802 * destroyed by IRQ13 bugs. Clearing FP exceptions is not an acceptable 803 * solution for signals other than SIGFPE. 804 */ 805int 806npxtrap() 807{ 808 critical_t savecrit; 809 u_short control, status; 810 u_long *exstat; 811 812 if (!npx_exists) { 813 printf("npxtrap: npxthread = %p, curthread = %p, npx_exists = %d\n", 814 PCPU_GET(npxthread), curthread, npx_exists); 815 panic("npxtrap from nowhere"); 816 } 817 savecrit = critical_enter(); 818 819 /* 820 * Interrupt handling (for another interrupt) may have pushed the 821 * state to memory. Fetch the relevant parts of the state from 822 * wherever they are. 823 */ 824 if (PCPU_GET(npxthread) != curthread) { 825 control = GET_FPU_CW(curthread); 826 status = GET_FPU_SW(curthread); 827 } else { 828 fnstcw(&control); 829 fnstsw(&status); 830 } 831 832 exstat = GET_FPU_EXSW_PTR(curthread->td_pcb); 833 *exstat = status; 834 if (PCPU_GET(npxthread) != curthread) 835 GET_FPU_SW(curthread) &= ~0x80bf; 836 else 837 fnclex(); 838 critical_exit(savecrit); 839 return (fpetable[status & ((~control & 0x3f) | 0x40)]); 840} 841 842/* 843 * Implement device not available (DNA) exception 844 * 845 * It would be better to switch FP context here (if curthread != npxthread) 846 * and not necessarily for every context switch, but it is too hard to 847 * access foreign pcb's. 848 */ 849int 850npxdna() 851{ 852 u_long *exstat; 853 critical_t s; 854 855 if (!npx_exists) 856 return (0); 857 if (PCPU_GET(npxthread) != NULL) { 858 printf("npxdna: npxthread = %p, curthread = %p\n", 859 PCPU_GET(npxthread), curthread); 860 panic("npxdna"); 861 } 862 s = critical_enter(); 863 stop_emulating(); 864 /* 865 * Record new context early in case frstor causes an IRQ13. 866 */ 867 PCPU_SET(npxthread, curthread); 868 869 exstat = GET_FPU_EXSW_PTR(PCPU_GET(curpcb)); 870 *exstat = 0; 871 /* 872 * The following frstor may cause an IRQ13 when the state being 873 * restored has a pending error. The error will appear to have been 874 * triggered by the current (npx) user instruction even when that 875 * instruction is a no-wait instruction that should not trigger an 876 * error (e.g., fnclex). On at least one 486 system all of the 877 * no-wait instructions are broken the same as frstor, so our 878 * treatment does not amplify the breakage. On at least one 879 * 386/Cyrix 387 system, fnclex works correctly while frstor and 880 * fnsave are broken, so our treatment breaks fnclex if it is the 881 * first FPU instruction after a context switch. 882 */ 883 fpurstor(&PCPU_GET(curpcb)->pcb_save); 884 critical_exit(s); 885 886 return (1); 887} 888 889/* 890 * Wrapper for fnsave instruction, partly to handle hardware bugs. When npx 891 * exceptions are reported via IRQ13, spurious IRQ13's may be triggered by 892 * no-wait npx instructions. See the Intel application note AP-578 for 893 * details. This doesn't cause any additional complications here. IRQ13's 894 * are inherently asynchronous unless the CPU is frozen to deliver them -- 895 * one that started in userland may be delivered many instructions later, 896 * after the process has entered the kernel. It may even be delivered after 897 * the fnsave here completes. A spurious IRQ13 for the fnsave is handled in 898 * the same way as a very-late-arriving non-spurious IRQ13 from user mode: 899 * it is normally ignored at first because we set npxthread to NULL; it is 900 * normally retriggered in npxdna() after return to user mode. 901 * 902 * npxsave() must be called with interrupts disabled, so that it clears 903 * npxthread atomically with saving the state. We require callers to do the 904 * disabling, since most callers need to disable interrupts anyway to call 905 * npxsave() atomically with checking npxthread. 906 * 907 * A previous version of npxsave() went to great lengths to excecute fnsave 908 * with interrupts enabled in case executing it froze the CPU. This case 909 * can't happen, at least for Intel CPU/NPX's. Spurious IRQ13's don't imply 910 * spurious freezes. 911 */ 912void 913npxsave(addr) 914 union savefpu *addr; 915{ 916 917 stop_emulating(); 918 fpusave(addr); 919 920 start_emulating(); 921 PCPU_SET(npxthread, NULL); 922} 923 924static void 925fpusave(addr) 926 union savefpu *addr; 927{ 928 929#ifdef CPU_ENABLE_SSE 930 if (cpu_fxsr) 931 fxsave(addr); 932 else 933#endif 934 fnsave(addr); 935} 936 937static void 938fpurstor(addr) 939 union savefpu *addr; 940{ 941 942#ifdef CPU_ENABLE_SSE 943 if (cpu_fxsr) 944 fxrstor(addr); 945 else 946#endif 947 frstor(addr); 948} 949 950#ifdef I586_CPU_XXX 951static long 952timezero(funcname, func) 953 const char *funcname; 954 void (*func) __P((void *buf, size_t len)); 955 956{ 957 void *buf; 958#define BUFSIZE 1048576 959 long usec; 960 struct timeval finish, start; 961 962 buf = malloc(BUFSIZE, M_TEMP, M_NOWAIT); 963 if (buf == NULL) 964 return (BUFSIZE); 965 microtime(&start); 966 (*func)(buf, BUFSIZE); 967 microtime(&finish); 968 usec = 1000000 * (finish.tv_sec - start.tv_sec) + 969 finish.tv_usec - start.tv_usec; 970 if (usec <= 0) 971 usec = 1; 972 if (bootverbose) 973 printf("%s bandwidth = %u kBps\n", funcname, 974 (u_int32_t)(((BUFSIZE >> 10) * 1000000) / usec)); 975 free(buf, M_TEMP); 976 return (usec); 977} 978#endif /* I586_CPU */ 979 980static device_method_t npx_methods[] = { 981 /* Device interface */ 982 DEVMETHOD(device_identify, npx_identify), 983 DEVMETHOD(device_probe, npx_probe), 984 DEVMETHOD(device_attach, npx_attach), 985 DEVMETHOD(device_detach, bus_generic_detach), 986 DEVMETHOD(device_shutdown, bus_generic_shutdown), 987 DEVMETHOD(device_suspend, bus_generic_suspend), 988 DEVMETHOD(device_resume, bus_generic_resume), 989 990 { 0, 0 } 991}; 992 993static driver_t npx_driver = { 994 "npx", 995 npx_methods, 996 1, /* no softc */ 997}; 998 999static devclass_t npx_devclass; 1000 1001/* 1002 * We prefer to attach to the root nexus so that the usual case (exception 16) 1003 * doesn't describe the processor as being `on isa'. 1004 */ 1005DRIVER_MODULE(npx, nexus, npx_driver, npx_devclass, 0, 0); 1006 1007/* 1008 * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI. 1009 */ 1010static struct isa_pnp_id npxisa_ids[] = { 1011 { 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */ 1012 { 0 } 1013}; 1014 1015static int 1016npxisa_probe(device_t dev) 1017{ 1018 int result; 1019 if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, npxisa_ids)) <= 0) { 1020 device_quiet(dev); 1021 } 1022 return(result); 1023} 1024 1025static int 1026npxisa_attach(device_t dev) 1027{ 1028 return (0); 1029} 1030 1031static device_method_t npxisa_methods[] = { 1032 /* Device interface */ 1033 DEVMETHOD(device_probe, npxisa_probe), 1034 DEVMETHOD(device_attach, npxisa_attach), 1035 DEVMETHOD(device_detach, bus_generic_detach), 1036 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1037 DEVMETHOD(device_suspend, bus_generic_suspend), 1038 DEVMETHOD(device_resume, bus_generic_resume), 1039 1040 { 0, 0 } 1041}; 1042 1043static driver_t npxisa_driver = { 1044 "npxisa", 1045 npxisa_methods, 1046 1, /* no softc */ 1047}; 1048 1049static devclass_t npxisa_devclass; 1050 1051DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0); 1052DRIVER_MODULE(npxisa, acpi, npxisa_driver, npxisa_devclass, 0, 0); 1053 1054