xref: /freebsd/sys/amd64/amd64/fpu.c (revision 77a0943ded95b9e6438f7db70c4a28e4d93946d4)
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  * $FreeBSD$
36  */
37 
38 #include "opt_debug_npx.h"
39 #include "opt_math_emulate.h"
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/bus.h>
44 #include <sys/ipl.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/module.h>
48 #include <sys/sysctl.h>
49 #include <sys/proc.h>
50 #include <machine/bus.h>
51 #include <sys/rman.h>
52 #ifdef NPX_DEBUG
53 #include <sys/syslog.h>
54 #endif
55 #include <sys/signalvar.h>
56 
57 #ifndef SMP
58 #include <machine/asmacros.h>
59 #endif
60 #include <machine/cputypes.h>
61 #include <machine/frame.h>
62 #include <machine/md_var.h>
63 #include <machine/pcb.h>
64 #include <machine/psl.h>
65 #ifndef SMP
66 #include <machine/clock.h>
67 #endif
68 #include <machine/resource.h>
69 #include <machine/specialreg.h>
70 #include <machine/segments.h>
71 
72 #ifndef SMP
73 #include <i386/isa/icu.h>
74 #include <i386/isa/intr_machdep.h>
75 #include <i386/isa/isa.h>
76 #endif
77 #include <isa/isavar.h>
78 
79 /*
80  * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
81  */
82 
83 /* Configuration flags. */
84 #define	NPX_DISABLE_I586_OPTIMIZED_BCOPY	(1 << 0)
85 #define	NPX_DISABLE_I586_OPTIMIZED_BZERO	(1 << 1)
86 #define	NPX_DISABLE_I586_OPTIMIZED_COPYIO	(1 << 2)
87 #define	NPX_PREFER_EMULATOR			(1 << 3)
88 
89 #ifdef	__GNUC__
90 
91 #define	fldcw(addr)		__asm("fldcw %0" : : "m" (*(addr)))
92 #define	fnclex()		__asm("fnclex")
93 #define	fninit()		__asm("fninit")
94 #define	fnop()			__asm("fnop")
95 #define	fnsave(addr)		__asm __volatile("fnsave %0" : "=m" (*(addr)))
96 #define	fnstcw(addr)		__asm __volatile("fnstcw %0" : "=m" (*(addr)))
97 #define	fnstsw(addr)		__asm __volatile("fnstsw %0" : "=m" (*(addr)))
98 #define	fp_divide_by_0()	__asm("fldz; fld1; fdiv %st,%st(1); fnop")
99 #define	frstor(addr)		__asm("frstor %0" : : "m" (*(addr)))
100 #define	start_emulating()	__asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
101 				      : : "n" (CR0_TS) : "ax")
102 #define	stop_emulating()	__asm("clts")
103 
104 #else	/* not __GNUC__ */
105 
106 void	fldcw		__P((caddr_t addr));
107 void	fnclex		__P((void));
108 void	fninit		__P((void));
109 void	fnop		__P((void));
110 void	fnsave		__P((caddr_t addr));
111 void	fnstcw		__P((caddr_t addr));
112 void	fnstsw		__P((caddr_t addr));
113 void	fp_divide_by_0	__P((void));
114 void	frstor		__P((caddr_t addr));
115 void	start_emulating	__P((void));
116 void	stop_emulating	__P((void));
117 
118 #endif	/* __GNUC__ */
119 
120 typedef u_char bool_t;
121 
122 static	int	npx_attach	__P((device_t dev));
123 	void	npx_intr	__P((void *));
124 static	void	npx_identify	__P((driver_t *driver, device_t parent));
125 static	int	npx_probe	__P((device_t dev));
126 static	int	npx_probe1	__P((device_t dev));
127 #ifdef I586_CPU
128 static	long	timezero	__P((const char *funcname,
129 				     void (*func)(void *buf, size_t len)));
130 #endif /* I586_CPU */
131 
132 int	hw_float;		/* XXX currently just alias for npx_exists */
133 
134 SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
135 	CTLFLAG_RD, &hw_float, 0,
136 	"Floatingpoint instructions executed in hardware");
137 
138 #ifndef SMP
139 static	u_int			npx0_imask = 0;
140 static	struct gate_descriptor	npx_idt_probeintr;
141 static	int			npx_intrno;
142 static	volatile u_int		npx_intrs_while_probing;
143 static	volatile u_int		npx_traps_while_probing;
144 #endif
145 
146 static	bool_t			npx_ex16;
147 static	bool_t			npx_exists;
148 static	bool_t			npx_irq13;
149 static	int			npx_irq;	/* irq number */
150 
151 #ifndef SMP
152 /*
153  * Special interrupt handlers.  Someday intr0-intr15 will be used to count
154  * interrupts.  We'll still need a special exception 16 handler.  The busy
155  * latch stuff in probeintr() can be moved to npxprobe().
156  */
157 inthand_t probeintr;
158 __asm("								\n\
159 	.text							\n\
160 	.p2align 2,0x90						\n\
161 	.type	" __XSTRING(CNAME(probeintr)) ",@function	\n\
162 " __XSTRING(CNAME(probeintr)) ":				\n\
163 	ss							\n\
164 	incl	" __XSTRING(CNAME(npx_intrs_while_probing)) "	\n\
165 	pushl	%eax						\n\
166 	movb	$0x20,%al	# EOI (asm in strings loses cpp features) \n\
167 	outb	%al,$0xa0	# IO_ICU2			\n\
168 	outb	%al,$0x20	# IO_ICU1			\n\
169 	movb	$0,%al						\n\
170 	outb	%al,$0xf0	# clear BUSY# latch		\n\
171 	popl	%eax						\n\
172 	iret							\n\
173 ");
174 
175 inthand_t probetrap;
176 __asm("								\n\
177 	.text							\n\
178 	.p2align 2,0x90						\n\
179 	.type	" __XSTRING(CNAME(probetrap)) ",@function	\n\
180 " __XSTRING(CNAME(probetrap)) ":				\n\
181 	ss							\n\
182 	incl	" __XSTRING(CNAME(npx_traps_while_probing)) "	\n\
183 	fnclex							\n\
184 	iret							\n\
185 ");
186 #endif /* SMP */
187 
188 /*
189  * Identify routine.  Create a connection point on our parent for probing.
190  */
191 static void
192 npx_identify(driver, parent)
193 	driver_t *driver;
194 	device_t parent;
195 {
196 	device_t child;
197 
198 	child = BUS_ADD_CHILD(parent, 0, "npx", 0);
199 	if (child == NULL)
200 		panic("npx_identify");
201 }
202 
203 /*
204  * Probe routine.  Initialize cr0 to give correct behaviour for [f]wait
205  * whether the device exists or not (XXX should be elsewhere).  Set flags
206  * to tell npxattach() what to do.  Modify device struct if npx doesn't
207  * need to use interrupts.  Return 1 if device exists.
208  */
209 static int
210 npx_probe(dev)
211 	device_t dev;
212 {
213 #ifdef SMP
214 
215 	if (resource_int_value("npx", 0, "irq", &npx_irq) != 0)
216 		npx_irq = 13;
217 	return npx_probe1(dev);
218 
219 #else /* SMP */
220 
221 	int	result;
222 	u_long	save_eflags;
223 	u_char	save_icu1_mask;
224 	u_char	save_icu2_mask;
225 	struct	gate_descriptor save_idt_npxintr;
226 	struct	gate_descriptor save_idt_npxtrap;
227 	/*
228 	 * This routine is now just a wrapper for npxprobe1(), to install
229 	 * special npx interrupt and trap handlers, to enable npx interrupts
230 	 * and to disable other interrupts.  Someday isa_configure() will
231 	 * install suitable handlers and run with interrupts enabled so we
232 	 * won't need to do so much here.
233 	 */
234 	if (resource_int_value("npx", 0, "irq", &npx_irq) != 0)
235 		npx_irq = 13;
236 	npx_intrno = NRSVIDT + npx_irq;
237 	save_eflags = read_eflags();
238 	disable_intr();
239 	save_icu1_mask = inb(IO_ICU1 + 1);
240 	save_icu2_mask = inb(IO_ICU2 + 1);
241 	save_idt_npxintr = idt[npx_intrno];
242 	save_idt_npxtrap = idt[16];
243 	outb(IO_ICU1 + 1, ~IRQ_SLAVE);
244 	outb(IO_ICU2 + 1, ~(1 << (npx_irq - 8)));
245 	setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
246 	setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
247 	npx_idt_probeintr = idt[npx_intrno];
248 
249 	/*
250 	 * XXX This looks highly bogus, but it appears that npc_probe1
251 	 * needs interrupts enabled.  Does this make any difference
252 	 * here?
253 	 */
254 	enable_intr();
255 	result = npx_probe1(dev);
256 	disable_intr();
257 	outb(IO_ICU1 + 1, save_icu1_mask);
258 	outb(IO_ICU2 + 1, save_icu2_mask);
259 	idt[npx_intrno] = save_idt_npxintr;
260 	idt[16] = save_idt_npxtrap;
261 	write_eflags(save_eflags);
262 	return (result);
263 
264 #endif /* SMP */
265 }
266 
267 static int
268 npx_probe1(dev)
269 	device_t dev;
270 {
271 #ifndef SMP
272 	u_short control;
273 	u_short status;
274 #endif
275 
276 	/*
277 	 * Partially reset the coprocessor, if any.  Some BIOS's don't reset
278 	 * it after a warm boot.
279 	 */
280 	outb(0xf1, 0);		/* full reset on some systems, NOP on others */
281 	outb(0xf0, 0);		/* clear BUSY# latch */
282 	/*
283 	 * Prepare to trap all ESC (i.e., NPX) instructions and all WAIT
284 	 * instructions.  We must set the CR0_MP bit and use the CR0_TS
285 	 * bit to control the trap, because setting the CR0_EM bit does
286 	 * not cause WAIT instructions to trap.  It's important to trap
287 	 * WAIT instructions - otherwise the "wait" variants of no-wait
288 	 * control instructions would degenerate to the "no-wait" variants
289 	 * after FP context switches but work correctly otherwise.  It's
290 	 * particularly important to trap WAITs when there is no NPX -
291 	 * otherwise the "wait" variants would always degenerate.
292 	 *
293 	 * Try setting CR0_NE to get correct error reporting on 486DX's.
294 	 * Setting it should fail or do nothing on lesser processors.
295 	 */
296 	load_cr0(rcr0() | CR0_MP | CR0_NE);
297 	/*
298 	 * But don't trap while we're probing.
299 	 */
300 	stop_emulating();
301 	/*
302 	 * Finish resetting the coprocessor, if any.  If there is an error
303 	 * pending, then we may get a bogus IRQ13, but probeintr() will handle
304 	 * it OK.  Bogus halts have never been observed, but we enabled
305 	 * IRQ13 and cleared the BUSY# latch early to handle them anyway.
306 	 */
307 	fninit();
308 
309 #ifdef SMP
310 	/*
311 	 * Exception 16 MUST work for SMP.
312 	 */
313 	npx_irq13 = 0;
314 	npx_ex16 = hw_float = npx_exists = 1;
315 	device_set_desc(dev, "math processor");
316 	return (0);
317 
318 #else /* !SMP */
319 	device_set_desc(dev, "math processor");
320 
321 	/*
322 	 * Don't use fwait here because it might hang.
323 	 * Don't use fnop here because it usually hangs if there is no FPU.
324 	 */
325 	DELAY(1000);		/* wait for any IRQ13 */
326 #ifdef DIAGNOSTIC
327 	if (npx_intrs_while_probing != 0)
328 		printf("fninit caused %u bogus npx interrupt(s)\n",
329 		       npx_intrs_while_probing);
330 	if (npx_traps_while_probing != 0)
331 		printf("fninit caused %u bogus npx trap(s)\n",
332 		       npx_traps_while_probing);
333 #endif
334 	/*
335 	 * Check for a status of mostly zero.
336 	 */
337 	status = 0x5a5a;
338 	fnstsw(&status);
339 	if ((status & 0xb8ff) == 0) {
340 		/*
341 		 * Good, now check for a proper control word.
342 		 */
343 		control = 0x5a5a;
344 		fnstcw(&control);
345 		if ((control & 0x1f3f) == 0x033f) {
346 			hw_float = npx_exists = 1;
347 			/*
348 			 * We have an npx, now divide by 0 to see if exception
349 			 * 16 works.
350 			 */
351 			control &= ~(1 << 2);	/* enable divide by 0 trap */
352 			fldcw(&control);
353 			npx_traps_while_probing = npx_intrs_while_probing = 0;
354 			fp_divide_by_0();
355 			if (npx_traps_while_probing != 0) {
356 				/*
357 				 * Good, exception 16 works.
358 				 */
359 				npx_ex16 = 1;
360 				return (0);
361 			}
362 			if (npx_intrs_while_probing != 0) {
363 				int	rid;
364 				struct	resource *r;
365 				void	*intr;
366 				/*
367 				 * Bad, we are stuck with IRQ13.
368 				 */
369 				npx_irq13 = 1;
370 				/*
371 				 * npxattach would be too late to set npx0_imask
372 				 */
373 				npx0_imask |= (1 << npx_irq);
374 
375 				/*
376 				 * We allocate these resources permanently,
377 				 * so there is no need to keep track of them.
378 				 */
379 				rid = 0;
380 				r = bus_alloc_resource(dev, SYS_RES_IOPORT,
381 						       &rid, IO_NPX, IO_NPX,
382 						       IO_NPXSIZE, RF_ACTIVE);
383 				if (r == 0)
384 					panic("npx: can't get ports");
385 				rid = 0;
386 				r = bus_alloc_resource(dev, SYS_RES_IRQ,
387 						       &rid, npx_irq, npx_irq,
388 						       1, RF_ACTIVE);
389 				if (r == 0)
390 					panic("npx: can't get IRQ");
391 				BUS_SETUP_INTR(device_get_parent(dev),
392 					       dev, r, INTR_TYPE_MISC,
393 					       npx_intr, 0, &intr);
394 				if (intr == 0)
395 					panic("npx: can't create intr");
396 
397 				return (0);
398 			}
399 			/*
400 			 * Worse, even IRQ13 is broken.  Use emulator.
401 			 */
402 		}
403 	}
404 	/*
405 	 * Probe failed, but we want to get to npxattach to initialize the
406 	 * emulator and say that it has been installed.  XXX handle devices
407 	 * that aren't really devices better.
408 	 */
409 	return (0);
410 #endif /* SMP */
411 }
412 
413 /*
414  * Attach routine - announce which it is, and wire into system
415  */
416 int
417 npx_attach(dev)
418 	device_t dev;
419 {
420 	int flags;
421 
422 	if (resource_int_value("npx", 0, "flags", &flags) != 0)
423 		flags = 0;
424 
425 	if (flags)
426 		device_printf(dev, "flags 0x%x ", flags);
427 	if (npx_irq13) {
428 		device_printf(dev, "using IRQ 13 interface\n");
429 	} else {
430 #if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE)
431 		if (npx_ex16) {
432 			if (!(flags & NPX_PREFER_EMULATOR))
433 				device_printf(dev, "INT 16 interface\n");
434 			else {
435 				device_printf(dev, "FPU exists, but flags request "
436 				    "emulator\n");
437 				hw_float = npx_exists = 0;
438 			}
439 		} else if (npx_exists) {
440 			device_printf(dev, "error reporting broken; using 387 emulator\n");
441 			hw_float = npx_exists = 0;
442 		} else
443 			device_printf(dev, "387 emulator\n");
444 #else
445 		if (npx_ex16) {
446 			device_printf(dev, "INT 16 interface\n");
447 			if (flags & NPX_PREFER_EMULATOR) {
448 				device_printf(dev, "emulator requested, but none compiled "
449 				    "into kernel, using FPU\n");
450 			}
451 		} else
452 			device_printf(dev, "no 387 emulator in kernel and no FPU!\n");
453 #endif
454 	}
455 	npxinit(__INITIAL_NPXCW__);
456 
457 #ifdef I586_CPU
458 	if (cpu_class == CPUCLASS_586 && npx_ex16 && npx_exists &&
459 	    timezero("i586_bzero()", i586_bzero) <
460 	    timezero("bzero()", bzero) * 4 / 5) {
461 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) {
462 			bcopy_vector = i586_bcopy;
463 			ovbcopy_vector = i586_bcopy;
464 		}
465 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BZERO))
466 			bzero = i586_bzero;
467 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) {
468 			copyin_vector = i586_copyin;
469 			copyout_vector = i586_copyout;
470 		}
471 	}
472 #endif
473 
474 	return (0);		/* XXX unused */
475 }
476 
477 /*
478  * Initialize floating point unit.
479  */
480 void
481 npxinit(control)
482 	u_short control;
483 {
484 	struct save87 dummy;
485 
486 	if (!npx_exists)
487 		return;
488 	/*
489 	 * fninit has the same h/w bugs as fnsave.  Use the detoxified
490 	 * fnsave to throw away any junk in the fpu.  npxsave() initializes
491 	 * the fpu and sets npxproc = NULL as important side effects.
492 	 */
493 	npxsave(&dummy);
494 	stop_emulating();
495 	fldcw(&control);
496 	if (curpcb != NULL)
497 		fnsave(&curpcb->pcb_savefpu);
498 	start_emulating();
499 }
500 
501 /*
502  * Free coprocessor (if we have it).
503  */
504 void
505 npxexit(p)
506 	struct proc *p;
507 {
508 
509 	if (p == npxproc)
510 		npxsave(&curpcb->pcb_savefpu);
511 #ifdef NPX_DEBUG
512 	if (npx_exists) {
513 		u_int	masked_exceptions;
514 
515 		masked_exceptions = curpcb->pcb_savefpu.sv_env.en_cw
516 				    & curpcb->pcb_savefpu.sv_env.en_sw & 0x7f;
517 		/*
518 		 * Log exceptions that would have trapped with the old
519 		 * control word (overflow, divide by 0, and invalid operand).
520 		 */
521 		if (masked_exceptions & 0x0d)
522 			log(LOG_ERR,
523 	"pid %d (%s) exited with masked floating point exceptions 0x%02x\n",
524 			    p->p_pid, p->p_comm, masked_exceptions);
525 	}
526 #endif
527 }
528 
529 /*
530  * The following mechanism is used to ensure that the FPE_... value
531  * that is passed as a trapcode to the signal handler of the user
532  * process does not have more than one bit set.
533  *
534  * Multiple bits may be set if the user process modifies the control
535  * word while a status word bit is already set.  While this is a sign
536  * of bad coding, we have no choise than to narrow them down to one
537  * bit, since we must not send a trapcode that is not exactly one of
538  * the FPE_ macros.
539  *
540  * The mechanism has a static table with 127 entries.  Each combination
541  * of the 7 FPU status word exception bits directly translates to a
542  * position in this table, where a single FPE_... value is stored.
543  * This FPE_... value stored there is considered the "most important"
544  * of the exception bits and will be sent as the signal code.  The
545  * precedence of the bits is based upon Intel Document "Numerical
546  * Applications", Chapter "Special Computational Situations".
547  *
548  * The macro to choose one of these values does these steps: 1) Throw
549  * away status word bits that cannot be masked.  2) Throw away the bits
550  * currently masked in the control word, assuming the user isn't
551  * interested in them anymore.  3) Reinsert status word bit 7 (stack
552  * fault) if it is set, which cannot be masked but must be presered.
553  * 4) Use the remaining bits to point into the trapcode table.
554  *
555  * The 6 maskable bits in order of their preference, as stated in the
556  * above referenced Intel manual:
557  * 1  Invalid operation (FP_X_INV)
558  * 1a   Stack underflow
559  * 1b   Stack overflow
560  * 1c   Operand of unsupported format
561  * 1d   SNaN operand.
562  * 2  QNaN operand (not an exception, irrelavant here)
563  * 3  Any other invalid-operation not mentioned above or zero divide
564  *      (FP_X_INV, FP_X_DZ)
565  * 4  Denormal operand (FP_X_DNML)
566  * 5  Numeric over/underflow (FP_X_OFL, FP_X_UFL)
567  * 6  Inexact result (FP_X_IMP)
568  */
569 static char fpetable[128] = {
570 	0,
571 	FPE_FLTINV,	/*  1 - INV */
572 	FPE_FLTUND,	/*  2 - DNML */
573 	FPE_FLTINV,	/*  3 - INV | DNML */
574 	FPE_FLTDIV,	/*  4 - DZ */
575 	FPE_FLTINV,	/*  5 - INV | DZ */
576 	FPE_FLTDIV,	/*  6 - DNML | DZ */
577 	FPE_FLTINV,	/*  7 - INV | DNML | DZ */
578 	FPE_FLTOVF,	/*  8 - OFL */
579 	FPE_FLTINV,	/*  9 - INV | OFL */
580 	FPE_FLTUND,	/*  A - DNML | OFL */
581 	FPE_FLTINV,	/*  B - INV | DNML | OFL */
582 	FPE_FLTDIV,	/*  C - DZ | OFL */
583 	FPE_FLTINV,	/*  D - INV | DZ | OFL */
584 	FPE_FLTDIV,	/*  E - DNML | DZ | OFL */
585 	FPE_FLTINV,	/*  F - INV | DNML | DZ | OFL */
586 	FPE_FLTUND,	/* 10 - UFL */
587 	FPE_FLTINV,	/* 11 - INV | UFL */
588 	FPE_FLTUND,	/* 12 - DNML | UFL */
589 	FPE_FLTINV,	/* 13 - INV | DNML | UFL */
590 	FPE_FLTDIV,	/* 14 - DZ | UFL */
591 	FPE_FLTINV,	/* 15 - INV | DZ | UFL */
592 	FPE_FLTDIV,	/* 16 - DNML | DZ | UFL */
593 	FPE_FLTINV,	/* 17 - INV | DNML | DZ | UFL */
594 	FPE_FLTOVF,	/* 18 - OFL | UFL */
595 	FPE_FLTINV,	/* 19 - INV | OFL | UFL */
596 	FPE_FLTUND,	/* 1A - DNML | OFL | UFL */
597 	FPE_FLTINV,	/* 1B - INV | DNML | OFL | UFL */
598 	FPE_FLTDIV,	/* 1C - DZ | OFL | UFL */
599 	FPE_FLTINV,	/* 1D - INV | DZ | OFL | UFL */
600 	FPE_FLTDIV,	/* 1E - DNML | DZ | OFL | UFL */
601 	FPE_FLTINV,	/* 1F - INV | DNML | DZ | OFL | UFL */
602 	FPE_FLTRES,	/* 20 - IMP */
603 	FPE_FLTINV,	/* 21 - INV | IMP */
604 	FPE_FLTUND,	/* 22 - DNML | IMP */
605 	FPE_FLTINV,	/* 23 - INV | DNML | IMP */
606 	FPE_FLTDIV,	/* 24 - DZ | IMP */
607 	FPE_FLTINV,	/* 25 - INV | DZ | IMP */
608 	FPE_FLTDIV,	/* 26 - DNML | DZ | IMP */
609 	FPE_FLTINV,	/* 27 - INV | DNML | DZ | IMP */
610 	FPE_FLTOVF,	/* 28 - OFL | IMP */
611 	FPE_FLTINV,	/* 29 - INV | OFL | IMP */
612 	FPE_FLTUND,	/* 2A - DNML | OFL | IMP */
613 	FPE_FLTINV,	/* 2B - INV | DNML | OFL | IMP */
614 	FPE_FLTDIV,	/* 2C - DZ | OFL | IMP */
615 	FPE_FLTINV,	/* 2D - INV | DZ | OFL | IMP */
616 	FPE_FLTDIV,	/* 2E - DNML | DZ | OFL | IMP */
617 	FPE_FLTINV,	/* 2F - INV | DNML | DZ | OFL | IMP */
618 	FPE_FLTUND,	/* 30 - UFL | IMP */
619 	FPE_FLTINV,	/* 31 - INV | UFL | IMP */
620 	FPE_FLTUND,	/* 32 - DNML | UFL | IMP */
621 	FPE_FLTINV,	/* 33 - INV | DNML | UFL | IMP */
622 	FPE_FLTDIV,	/* 34 - DZ | UFL | IMP */
623 	FPE_FLTINV,	/* 35 - INV | DZ | UFL | IMP */
624 	FPE_FLTDIV,	/* 36 - DNML | DZ | UFL | IMP */
625 	FPE_FLTINV,	/* 37 - INV | DNML | DZ | UFL | IMP */
626 	FPE_FLTOVF,	/* 38 - OFL | UFL | IMP */
627 	FPE_FLTINV,	/* 39 - INV | OFL | UFL | IMP */
628 	FPE_FLTUND,	/* 3A - DNML | OFL | UFL | IMP */
629 	FPE_FLTINV,	/* 3B - INV | DNML | OFL | UFL | IMP */
630 	FPE_FLTDIV,	/* 3C - DZ | OFL | UFL | IMP */
631 	FPE_FLTINV,	/* 3D - INV | DZ | OFL | UFL | IMP */
632 	FPE_FLTDIV,	/* 3E - DNML | DZ | OFL | UFL | IMP */
633 	FPE_FLTINV,	/* 3F - INV | DNML | DZ | OFL | UFL | IMP */
634 	FPE_FLTSUB,	/* 40 - STK */
635 	FPE_FLTSUB,	/* 41 - INV | STK */
636 	FPE_FLTUND,	/* 42 - DNML | STK */
637 	FPE_FLTSUB,	/* 43 - INV | DNML | STK */
638 	FPE_FLTDIV,	/* 44 - DZ | STK */
639 	FPE_FLTSUB,	/* 45 - INV | DZ | STK */
640 	FPE_FLTDIV,	/* 46 - DNML | DZ | STK */
641 	FPE_FLTSUB,	/* 47 - INV | DNML | DZ | STK */
642 	FPE_FLTOVF,	/* 48 - OFL | STK */
643 	FPE_FLTSUB,	/* 49 - INV | OFL | STK */
644 	FPE_FLTUND,	/* 4A - DNML | OFL | STK */
645 	FPE_FLTSUB,	/* 4B - INV | DNML | OFL | STK */
646 	FPE_FLTDIV,	/* 4C - DZ | OFL | STK */
647 	FPE_FLTSUB,	/* 4D - INV | DZ | OFL | STK */
648 	FPE_FLTDIV,	/* 4E - DNML | DZ | OFL | STK */
649 	FPE_FLTSUB,	/* 4F - INV | DNML | DZ | OFL | STK */
650 	FPE_FLTUND,	/* 50 - UFL | STK */
651 	FPE_FLTSUB,	/* 51 - INV | UFL | STK */
652 	FPE_FLTUND,	/* 52 - DNML | UFL | STK */
653 	FPE_FLTSUB,	/* 53 - INV | DNML | UFL | STK */
654 	FPE_FLTDIV,	/* 54 - DZ | UFL | STK */
655 	FPE_FLTSUB,	/* 55 - INV | DZ | UFL | STK */
656 	FPE_FLTDIV,	/* 56 - DNML | DZ | UFL | STK */
657 	FPE_FLTSUB,	/* 57 - INV | DNML | DZ | UFL | STK */
658 	FPE_FLTOVF,	/* 58 - OFL | UFL | STK */
659 	FPE_FLTSUB,	/* 59 - INV | OFL | UFL | STK */
660 	FPE_FLTUND,	/* 5A - DNML | OFL | UFL | STK */
661 	FPE_FLTSUB,	/* 5B - INV | DNML | OFL | UFL | STK */
662 	FPE_FLTDIV,	/* 5C - DZ | OFL | UFL | STK */
663 	FPE_FLTSUB,	/* 5D - INV | DZ | OFL | UFL | STK */
664 	FPE_FLTDIV,	/* 5E - DNML | DZ | OFL | UFL | STK */
665 	FPE_FLTSUB,	/* 5F - INV | DNML | DZ | OFL | UFL | STK */
666 	FPE_FLTRES,	/* 60 - IMP | STK */
667 	FPE_FLTSUB,	/* 61 - INV | IMP | STK */
668 	FPE_FLTUND,	/* 62 - DNML | IMP | STK */
669 	FPE_FLTSUB,	/* 63 - INV | DNML | IMP | STK */
670 	FPE_FLTDIV,	/* 64 - DZ | IMP | STK */
671 	FPE_FLTSUB,	/* 65 - INV | DZ | IMP | STK */
672 	FPE_FLTDIV,	/* 66 - DNML | DZ | IMP | STK */
673 	FPE_FLTSUB,	/* 67 - INV | DNML | DZ | IMP | STK */
674 	FPE_FLTOVF,	/* 68 - OFL | IMP | STK */
675 	FPE_FLTSUB,	/* 69 - INV | OFL | IMP | STK */
676 	FPE_FLTUND,	/* 6A - DNML | OFL | IMP | STK */
677 	FPE_FLTSUB,	/* 6B - INV | DNML | OFL | IMP | STK */
678 	FPE_FLTDIV,	/* 6C - DZ | OFL | IMP | STK */
679 	FPE_FLTSUB,	/* 6D - INV | DZ | OFL | IMP | STK */
680 	FPE_FLTDIV,	/* 6E - DNML | DZ | OFL | IMP | STK */
681 	FPE_FLTSUB,	/* 6F - INV | DNML | DZ | OFL | IMP | STK */
682 	FPE_FLTUND,	/* 70 - UFL | IMP | STK */
683 	FPE_FLTSUB,	/* 71 - INV | UFL | IMP | STK */
684 	FPE_FLTUND,	/* 72 - DNML | UFL | IMP | STK */
685 	FPE_FLTSUB,	/* 73 - INV | DNML | UFL | IMP | STK */
686 	FPE_FLTDIV,	/* 74 - DZ | UFL | IMP | STK */
687 	FPE_FLTSUB,	/* 75 - INV | DZ | UFL | IMP | STK */
688 	FPE_FLTDIV,	/* 76 - DNML | DZ | UFL | IMP | STK */
689 	FPE_FLTSUB,	/* 77 - INV | DNML | DZ | UFL | IMP | STK */
690 	FPE_FLTOVF,	/* 78 - OFL | UFL | IMP | STK */
691 	FPE_FLTSUB,	/* 79 - INV | OFL | UFL | IMP | STK */
692 	FPE_FLTUND,	/* 7A - DNML | OFL | UFL | IMP | STK */
693 	FPE_FLTSUB,	/* 7B - INV | DNML | OFL | UFL | IMP | STK */
694 	FPE_FLTDIV,	/* 7C - DZ | OFL | UFL | IMP | STK */
695 	FPE_FLTSUB,	/* 7D - INV | DZ | OFL | UFL | IMP | STK */
696 	FPE_FLTDIV,	/* 7E - DNML | DZ | OFL | UFL | IMP | STK */
697 	FPE_FLTSUB,	/* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */
698 };
699 
700 /*
701  * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
702  *
703  * Clearing exceptions is necessary mainly to avoid IRQ13 bugs.  We now
704  * depend on longjmp() restoring a usable state.  Restoring the state
705  * or examining it might fail if we didn't clear exceptions.
706  *
707  * The error code chosen will be one of the FPE_... macros. It will be
708  * sent as the second argument to old BSD-style signal handlers and as
709  * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers.
710  *
711  * XXX the FP state is not preserved across signal handlers.  So signal
712  * handlers cannot afford to do FP unless they preserve the state or
713  * longjmp() out.  Both preserving the state and longjmp()ing may be
714  * destroyed by IRQ13 bugs.  Clearing FP exceptions is not an acceptable
715  * solution for signals other than SIGFPE.
716  */
717 void
718 npx_intr(dummy)
719 	void *dummy;
720 {
721 	int code;
722 	u_short control;
723 	struct intrframe *frame;
724 
725 	if (npxproc == NULL || !npx_exists) {
726 		printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
727 		       npxproc, curproc, npx_exists);
728 		panic("npxintr from nowhere");
729 	}
730 	if (npxproc != curproc) {
731 		printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
732 		       npxproc, curproc, npx_exists);
733 		panic("npxintr from non-current process");
734 	}
735 
736 	outb(0xf0, 0);
737 	fnstsw(&curpcb->pcb_savefpu.sv_ex_sw);
738 	fnstcw(&control);
739 	fnclex();
740 
741 	/*
742 	 * Pass exception to process.
743 	 */
744 	frame = (struct intrframe *)&dummy;	/* XXX */
745 	if ((ISPL(frame->if_cs) == SEL_UPL) || (frame->if_eflags & PSL_VM)) {
746 		/*
747 		 * Interrupt is essentially a trap, so we can afford to call
748 		 * the SIGFPE handler (if any) as soon as the interrupt
749 		 * returns.
750 		 *
751 		 * XXX little or nothing is gained from this, and plenty is
752 		 * lost - the interrupt frame has to contain the trap frame
753 		 * (this is otherwise only necessary for the rescheduling trap
754 		 * in doreti, and the frame for that could easily be set up
755 		 * just before it is used).
756 		 */
757 		curproc->p_md.md_regs = INTR_TO_TRAPFRAME(frame);
758 		/*
759 		 * Encode the appropriate code for detailed information on
760 		 * this exception.
761 		 */
762 		code =
763 		    fpetable[(curpcb->pcb_savefpu.sv_ex_sw & ~control & 0x3f) |
764 			(curpcb->pcb_savefpu.sv_ex_sw & 0x40)];
765 		trapsignal(curproc, SIGFPE, code);
766 	} else {
767 		/*
768 		 * Nested interrupt.  These losers occur when:
769 		 *	o an IRQ13 is bogusly generated at a bogus time, e.g.:
770 		 *		o immediately after an fnsave or frstor of an
771 		 *		  error state.
772 		 *		o a couple of 386 instructions after
773 		 *		  "fstpl _memvar" causes a stack overflow.
774 		 *	  These are especially nasty when combined with a
775 		 *	  trace trap.
776 		 *	o an IRQ13 occurs at the same time as another higher-
777 		 *	  priority interrupt.
778 		 *
779 		 * Treat them like a true async interrupt.
780 		 */
781 		psignal(curproc, SIGFPE);
782 	}
783 }
784 
785 /*
786  * Implement device not available (DNA) exception
787  *
788  * It would be better to switch FP context here (if curproc != npxproc)
789  * and not necessarily for every context switch, but it is too hard to
790  * access foreign pcb's.
791  */
792 int
793 npxdna()
794 {
795 	if (!npx_exists)
796 		return (0);
797 	if (npxproc != NULL) {
798 		printf("npxdna: npxproc = %p, curproc = %p\n",
799 		       npxproc, curproc);
800 		panic("npxdna");
801 	}
802 	stop_emulating();
803 	/*
804 	 * Record new context early in case frstor causes an IRQ13.
805 	 */
806 	PCPU_SET(npxproc, CURPROC);
807 	curpcb->pcb_savefpu.sv_ex_sw = 0;
808 	/*
809 	 * The following frstor may cause an IRQ13 when the state being
810 	 * restored has a pending error.  The error will appear to have been
811 	 * triggered by the current (npx) user instruction even when that
812 	 * instruction is a no-wait instruction that should not trigger an
813 	 * error (e.g., fnclex).  On at least one 486 system all of the
814 	 * no-wait instructions are broken the same as frstor, so our
815 	 * treatment does not amplify the breakage.  On at least one
816 	 * 386/Cyrix 387 system, fnclex works correctly while frstor and
817 	 * fnsave are broken, so our treatment breaks fnclex if it is the
818 	 * first FPU instruction after a context switch.
819 	 */
820 	frstor(&curpcb->pcb_savefpu);
821 
822 	return (1);
823 }
824 
825 /*
826  * Wrapper for fnsave instruction to handle h/w bugs.  If there is an error
827  * pending, then fnsave generates a bogus IRQ13 on some systems.  Force
828  * any IRQ13 to be handled immediately, and then ignore it.  This routine is
829  * often called at splhigh so it must not use many system services.  In
830  * particular, it's much easier to install a special handler than to
831  * guarantee that it's safe to use npxintr() and its supporting code.
832  */
833 void
834 npxsave(addr)
835 	struct save87 *addr;
836 {
837 #ifdef SMP
838 
839 	stop_emulating();
840 	fnsave(addr);
841 	/* fnop(); */
842 	start_emulating();
843 	PCPU_SET(npxproc, NULL);
844 
845 #else /* SMP */
846 
847 	int	intrstate;
848 	u_char	icu1_mask;
849 	u_char	icu2_mask;
850 	u_char	old_icu1_mask;
851 	u_char	old_icu2_mask;
852 	struct gate_descriptor	save_idt_npxintr;
853 
854 	intrstate = save_intr();
855 	disable_intr();
856 	old_icu1_mask = inb(IO_ICU1 + 1);
857 	old_icu2_mask = inb(IO_ICU2 + 1);
858 	save_idt_npxintr = idt[npx_intrno];
859 	outb(IO_ICU1 + 1, old_icu1_mask & ~(IRQ_SLAVE | npx0_imask));
860 	outb(IO_ICU2 + 1, old_icu2_mask & ~(npx0_imask >> 8));
861 	idt[npx_intrno] = npx_idt_probeintr;
862 	write_eflags(intrstate);
863 	stop_emulating();
864 	fnsave(addr);
865 	fnop();
866 	start_emulating();
867 	PCPU_SET(npxproc, NULL);
868 	disable_intr();
869 	icu1_mask = inb(IO_ICU1 + 1);	/* masks may have changed */
870 	icu2_mask = inb(IO_ICU2 + 1);
871 	outb(IO_ICU1 + 1,
872 	     (icu1_mask & ~npx0_imask) | (old_icu1_mask & npx0_imask));
873 	outb(IO_ICU2 + 1,
874 	     (icu2_mask & ~(npx0_imask >> 8))
875 	     | (old_icu2_mask & (npx0_imask >> 8)));
876 	idt[npx_intrno] = save_idt_npxintr;
877 	restore_intr(intrstate);	/* back to previous state */
878 
879 #endif /* SMP */
880 }
881 
882 #ifdef I586_CPU
883 static long
884 timezero(funcname, func)
885 	const char *funcname;
886 	void (*func) __P((void *buf, size_t len));
887 
888 {
889 	void *buf;
890 #define	BUFSIZE		1000000
891 	long usec;
892 	struct timeval finish, start;
893 
894 	buf = malloc(BUFSIZE, M_TEMP, M_NOWAIT);
895 	if (buf == NULL)
896 		return (BUFSIZE);
897 	microtime(&start);
898 	(*func)(buf, BUFSIZE);
899 	microtime(&finish);
900 	usec = 1000000 * (finish.tv_sec - start.tv_sec) +
901 	    finish.tv_usec - start.tv_usec;
902 	if (usec <= 0)
903 		usec = 1;
904 	if (bootverbose)
905 		printf("%s bandwidth = %ld bytes/sec\n",
906 		    funcname, (long)(BUFSIZE * (int64_t)1000000 / usec));
907 	free(buf, M_TEMP);
908 	return (usec);
909 }
910 #endif /* I586_CPU */
911 
912 static device_method_t npx_methods[] = {
913 	/* Device interface */
914 	DEVMETHOD(device_identify,	npx_identify),
915 	DEVMETHOD(device_probe,		npx_probe),
916 	DEVMETHOD(device_attach,	npx_attach),
917 	DEVMETHOD(device_detach,	bus_generic_detach),
918 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
919 	DEVMETHOD(device_suspend,	bus_generic_suspend),
920 	DEVMETHOD(device_resume,	bus_generic_resume),
921 
922 	{ 0, 0 }
923 };
924 
925 static driver_t npx_driver = {
926 	"npx",
927 	npx_methods,
928 	1,			/* no softc */
929 };
930 
931 static devclass_t npx_devclass;
932 
933 /*
934  * We prefer to attach to the root nexus so that the usual case (exception 16)
935  * doesn't describe the processor as being `on isa'.
936  */
937 DRIVER_MODULE(npx, nexus, npx_driver, npx_devclass, 0, 0);
938 
939 /*
940  * This sucks up the legacy ISA support assignments from PNPBIOS.
941  */
942 static struct isa_pnp_id npxisa_ids[] = {
943 	{ 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
944 	{ 0 }
945 };
946 
947 static int
948 npxisa_probe(device_t dev)
949 {
950 	int result;
951 	if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, npxisa_ids)) <= 0) {
952 		device_quiet(dev);
953 	}
954 	return(result);
955 }
956 
957 static int
958 npxisa_attach(device_t dev)
959 {
960 	return (0);
961 }
962 
963 static device_method_t npxisa_methods[] = {
964 	/* Device interface */
965 	DEVMETHOD(device_probe,		npxisa_probe),
966 	DEVMETHOD(device_attach,	npxisa_attach),
967 	DEVMETHOD(device_detach,	bus_generic_detach),
968 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
969 	DEVMETHOD(device_suspend,	bus_generic_suspend),
970 	DEVMETHOD(device_resume,	bus_generic_resume),
971 
972 	{ 0, 0 }
973 };
974 
975 static driver_t npxisa_driver = {
976 	"npxisa",
977 	npxisa_methods,
978 	1,			/* no softc */
979 };
980 
981 static devclass_t npxisa_devclass;
982 
983 DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0);
984 
985