xref: /freebsd/sys/amd64/amd64/fpu.c (revision ce4946daa5ce852d28008dac492029500ab2ee95)
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/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 
60 #ifndef SMP
61 #include <machine/asmacros.h>
62 #endif
63 #include <machine/cputypes.h>
64 #include <machine/frame.h>
65 #include <machine/md_var.h>
66 #include <machine/pcb.h>
67 #include <machine/psl.h>
68 #ifndef SMP
69 #include <machine/clock.h>
70 #endif
71 #include <machine/resource.h>
72 #include <machine/specialreg.h>
73 #include <machine/segments.h>
74 
75 #ifndef SMP
76 #include <i386/isa/icu.h>
77 #include <i386/isa/intr_machdep.h>
78 #include <i386/isa/isa.h>
79 #endif
80 #include <isa/isavar.h>
81 
82 /*
83  * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
84  */
85 
86 /* Configuration flags. */
87 #define	NPX_DISABLE_I586_OPTIMIZED_BCOPY	(1 << 0)
88 #define	NPX_DISABLE_I586_OPTIMIZED_BZERO	(1 << 1)
89 #define	NPX_DISABLE_I586_OPTIMIZED_COPYIO	(1 << 2)
90 #define	NPX_PREFER_EMULATOR			(1 << 3)
91 
92 #ifdef	__GNUC__
93 
94 #define	fldcw(addr)		__asm("fldcw %0" : : "m" (*(addr)))
95 #define	fnclex()		__asm("fnclex")
96 #define	fninit()		__asm("fninit")
97 #define	fnop()			__asm("fnop")
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 #define	start_emulating()	__asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
104 				      : : "n" (CR0_TS) : "ax")
105 #define	stop_emulating()	__asm("clts")
106 
107 #else	/* not __GNUC__ */
108 
109 void	fldcw		__P((caddr_t addr));
110 void	fnclex		__P((void));
111 void	fninit		__P((void));
112 void	fnop		__P((void));
113 void	fnsave		__P((caddr_t addr));
114 void	fnstcw		__P((caddr_t addr));
115 void	fnstsw		__P((caddr_t addr));
116 void	fp_divide_by_0	__P((void));
117 void	frstor		__P((caddr_t addr));
118 void	start_emulating	__P((void));
119 void	stop_emulating	__P((void));
120 
121 #endif	/* __GNUC__ */
122 
123 typedef u_char bool_t;
124 
125 static	int	npx_attach	__P((device_t dev));
126 	void	npx_intr	__P((void *));
127 static	void	npx_identify	__P((driver_t *driver, device_t parent));
128 static	int	npx_probe	__P((device_t dev));
129 static	int	npx_probe1	__P((device_t dev));
130 #ifdef I586_CPU
131 static	long	timezero	__P((const char *funcname,
132 				     void (*func)(void *buf, size_t len)));
133 #endif /* I586_CPU */
134 
135 int	hw_float;		/* XXX currently just alias for npx_exists */
136 
137 SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
138 	CTLFLAG_RD, &hw_float, 0,
139 	"Floatingpoint instructions executed in hardware");
140 
141 #ifndef SMP
142 static	u_int			npx0_imask = 0;
143 static	struct gate_descriptor	npx_idt_probeintr;
144 static	int			npx_intrno;
145 static	volatile u_int		npx_intrs_while_probing;
146 static	volatile u_int		npx_traps_while_probing;
147 #endif
148 
149 static	bool_t			npx_ex16;
150 static	bool_t			npx_exists;
151 static	bool_t			npx_irq13;
152 static	int			npx_irq;	/* irq number */
153 
154 #ifndef SMP
155 /*
156  * Special interrupt handlers.  Someday intr0-intr15 will be used to count
157  * interrupts.  We'll still need a special exception 16 handler.  The busy
158  * latch stuff in probeintr() can be moved to npxprobe().
159  */
160 inthand_t probeintr;
161 __asm("								\n\
162 	.text							\n\
163 	.p2align 2,0x90						\n\
164 	.type	" __XSTRING(CNAME(probeintr)) ",@function	\n\
165 " __XSTRING(CNAME(probeintr)) ":				\n\
166 	ss							\n\
167 	incl	" __XSTRING(CNAME(npx_intrs_while_probing)) "	\n\
168 	pushl	%eax						\n\
169 	movb	$0x20,%al	# EOI (asm in strings loses cpp features) \n\
170 	outb	%al,$0xa0	# IO_ICU2			\n\
171 	outb	%al,$0x20	# IO_ICU1			\n\
172 	movb	$0,%al						\n\
173 	outb	%al,$0xf0	# clear BUSY# latch		\n\
174 	popl	%eax						\n\
175 	iret							\n\
176 ");
177 
178 inthand_t probetrap;
179 __asm("								\n\
180 	.text							\n\
181 	.p2align 2,0x90						\n\
182 	.type	" __XSTRING(CNAME(probetrap)) ",@function	\n\
183 " __XSTRING(CNAME(probetrap)) ":				\n\
184 	ss							\n\
185 	incl	" __XSTRING(CNAME(npx_traps_while_probing)) "	\n\
186 	fnclex							\n\
187 	iret							\n\
188 ");
189 #endif /* SMP */
190 
191 /*
192  * Identify routine.  Create a connection point on our parent for probing.
193  */
194 static void
195 npx_identify(driver, parent)
196 	driver_t *driver;
197 	device_t parent;
198 {
199 	device_t child;
200 
201 	child = BUS_ADD_CHILD(parent, 0, "npx", 0);
202 	if (child == NULL)
203 		panic("npx_identify");
204 }
205 
206 /*
207  * Probe routine.  Initialize cr0 to give correct behaviour for [f]wait
208  * whether the device exists or not (XXX should be elsewhere).  Set flags
209  * to tell npxattach() what to do.  Modify device struct if npx doesn't
210  * need to use interrupts.  Return 1 if device exists.
211  */
212 static int
213 npx_probe(dev)
214 	device_t dev;
215 {
216 #ifdef SMP
217 
218 	if (resource_int_value("npx", 0, "irq", &npx_irq) != 0)
219 		npx_irq = 13;
220 	return npx_probe1(dev);
221 
222 #else /* SMP */
223 
224 	int	result;
225 	critical_t	savecrit;
226 	u_char	save_icu1_mask;
227 	u_char	save_icu2_mask;
228 	struct	gate_descriptor save_idt_npxintr;
229 	struct	gate_descriptor save_idt_npxtrap;
230 	/*
231 	 * This routine is now just a wrapper for npxprobe1(), to install
232 	 * special npx interrupt and trap handlers, to enable npx interrupts
233 	 * and to disable other interrupts.  Someday isa_configure() will
234 	 * install suitable handlers and run with interrupts enabled so we
235 	 * won't need to do so much here.
236 	 */
237 	if (resource_int_value("npx", 0, "irq", &npx_irq) != 0)
238 		npx_irq = 13;
239 	npx_intrno = NRSVIDT + npx_irq;
240 	savecrit = critical_enter();
241 	save_icu1_mask = inb(IO_ICU1 + 1);
242 	save_icu2_mask = inb(IO_ICU2 + 1);
243 	save_idt_npxintr = idt[npx_intrno];
244 	save_idt_npxtrap = idt[16];
245 	outb(IO_ICU1 + 1, ~IRQ_SLAVE);
246 	outb(IO_ICU2 + 1, ~(1 << (npx_irq - 8)));
247 	setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
248 	setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
249 	npx_idt_probeintr = idt[npx_intrno];
250 
251 	/*
252 	 * XXX This looks highly bogus, but it appears that npc_probe1
253 	 * needs interrupts enabled.  Does this make any difference
254 	 * here?
255 	 */
256 	critical_exit(savecrit);
257 	result = npx_probe1(dev);
258 	savecrit = critical_enter();
259 	outb(IO_ICU1 + 1, save_icu1_mask);
260 	outb(IO_ICU2 + 1, save_icu2_mask);
261 	idt[npx_intrno] = save_idt_npxintr;
262 	idt[16] = save_idt_npxtrap;
263 	critical_exit(savecrit);
264 	return (result);
265 
266 #endif /* SMP */
267 }
268 
269 static int
270 npx_probe1(dev)
271 	device_t dev;
272 {
273 #ifndef SMP
274 	u_short control;
275 	u_short status;
276 #endif
277 
278 	/*
279 	 * Partially reset the coprocessor, if any.  Some BIOS's don't reset
280 	 * it after a warm boot.
281 	 */
282 	outb(0xf1, 0);		/* full reset on some systems, NOP on others */
283 	outb(0xf0, 0);		/* clear BUSY# latch */
284 	/*
285 	 * Prepare to trap all ESC (i.e., NPX) instructions and all WAIT
286 	 * instructions.  We must set the CR0_MP bit and use the CR0_TS
287 	 * bit to control the trap, because setting the CR0_EM bit does
288 	 * not cause WAIT instructions to trap.  It's important to trap
289 	 * WAIT instructions - otherwise the "wait" variants of no-wait
290 	 * control instructions would degenerate to the "no-wait" variants
291 	 * after FP context switches but work correctly otherwise.  It's
292 	 * particularly important to trap WAITs when there is no NPX -
293 	 * otherwise the "wait" variants would always degenerate.
294 	 *
295 	 * Try setting CR0_NE to get correct error reporting on 486DX's.
296 	 * Setting it should fail or do nothing on lesser processors.
297 	 */
298 	load_cr0(rcr0() | CR0_MP | CR0_NE);
299 	/*
300 	 * But don't trap while we're probing.
301 	 */
302 	stop_emulating();
303 	/*
304 	 * Finish resetting the coprocessor, if any.  If there is an error
305 	 * pending, then we may get a bogus IRQ13, but probeintr() will handle
306 	 * it OK.  Bogus halts have never been observed, but we enabled
307 	 * IRQ13 and cleared the BUSY# latch early to handle them anyway.
308 	 */
309 	fninit();
310 
311 #ifdef SMP
312 	/*
313 	 * Exception 16 MUST work for SMP.
314 	 */
315 	npx_irq13 = 0;
316 	npx_ex16 = hw_float = npx_exists = 1;
317 	device_set_desc(dev, "math processor");
318 	return (0);
319 
320 #else /* !SMP */
321 	device_set_desc(dev, "math processor");
322 
323 	/*
324 	 * Don't use fwait here because it might hang.
325 	 * Don't use fnop here because it usually hangs if there is no FPU.
326 	 */
327 	DELAY(1000);		/* wait for any IRQ13 */
328 #ifdef DIAGNOSTIC
329 	if (npx_intrs_while_probing != 0)
330 		printf("fninit caused %u bogus npx interrupt(s)\n",
331 		       npx_intrs_while_probing);
332 	if (npx_traps_while_probing != 0)
333 		printf("fninit caused %u bogus npx trap(s)\n",
334 		       npx_traps_while_probing);
335 #endif
336 	/*
337 	 * Check for a status of mostly zero.
338 	 */
339 	status = 0x5a5a;
340 	fnstsw(&status);
341 	if ((status & 0xb8ff) == 0) {
342 		/*
343 		 * Good, now check for a proper control word.
344 		 */
345 		control = 0x5a5a;
346 		fnstcw(&control);
347 		if ((control & 0x1f3f) == 0x033f) {
348 			hw_float = npx_exists = 1;
349 			/*
350 			 * We have an npx, now divide by 0 to see if exception
351 			 * 16 works.
352 			 */
353 			control &= ~(1 << 2);	/* enable divide by 0 trap */
354 			fldcw(&control);
355 			npx_traps_while_probing = npx_intrs_while_probing = 0;
356 			fp_divide_by_0();
357 			if (npx_traps_while_probing != 0) {
358 				/*
359 				 * Good, exception 16 works.
360 				 */
361 				npx_ex16 = 1;
362 				return (0);
363 			}
364 			if (npx_intrs_while_probing != 0) {
365 				int	rid;
366 				struct	resource *r;
367 				void	*intr;
368 				/*
369 				 * Bad, we are stuck with IRQ13.
370 				 */
371 				npx_irq13 = 1;
372 				/*
373 				 * npxattach would be too late to set npx0_imask
374 				 */
375 				npx0_imask |= (1 << npx_irq);
376 
377 				/*
378 				 * We allocate these resources permanently,
379 				 * so there is no need to keep track of them.
380 				 */
381 				rid = 0;
382 				r = bus_alloc_resource(dev, SYS_RES_IOPORT,
383 						       &rid, IO_NPX, IO_NPX,
384 						       IO_NPXSIZE, RF_ACTIVE);
385 				if (r == 0)
386 					panic("npx: can't get ports");
387 				rid = 0;
388 				r = bus_alloc_resource(dev, SYS_RES_IRQ,
389 						       &rid, npx_irq, npx_irq,
390 						       1, RF_ACTIVE);
391 				if (r == 0)
392 					panic("npx: can't get IRQ");
393 				BUS_SETUP_INTR(device_get_parent(dev),
394 					       dev, r,
395 					       INTR_TYPE_MISC | INTR_MPSAFE,
396 					       npx_intr, 0, &intr);
397 				if (intr == 0)
398 					panic("npx: can't create intr");
399 
400 				return (0);
401 			}
402 			/*
403 			 * Worse, even IRQ13 is broken.  Use emulator.
404 			 */
405 		}
406 	}
407 	/*
408 	 * Probe failed, but we want to get to npxattach to initialize the
409 	 * emulator and say that it has been installed.  XXX handle devices
410 	 * that aren't really devices better.
411 	 */
412 	return (0);
413 #endif /* SMP */
414 }
415 
416 /*
417  * Attach routine - announce which it is, and wire into system
418  */
419 int
420 npx_attach(dev)
421 	device_t dev;
422 {
423 	int flags;
424 
425 	if (resource_int_value("npx", 0, "flags", &flags) != 0)
426 		flags = 0;
427 
428 	if (flags)
429 		device_printf(dev, "flags 0x%x ", flags);
430 	if (npx_irq13) {
431 		device_printf(dev, "using IRQ 13 interface\n");
432 	} else {
433 #if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE)
434 		if (npx_ex16) {
435 			if (!(flags & NPX_PREFER_EMULATOR))
436 				device_printf(dev, "INT 16 interface\n");
437 			else {
438 				device_printf(dev, "FPU exists, but flags request "
439 				    "emulator\n");
440 				hw_float = npx_exists = 0;
441 			}
442 		} else if (npx_exists) {
443 			device_printf(dev, "error reporting broken; using 387 emulator\n");
444 			hw_float = npx_exists = 0;
445 		} else
446 			device_printf(dev, "387 emulator\n");
447 #else
448 		if (npx_ex16) {
449 			device_printf(dev, "INT 16 interface\n");
450 			if (flags & NPX_PREFER_EMULATOR) {
451 				device_printf(dev, "emulator requested, but none compiled "
452 				    "into kernel, using FPU\n");
453 			}
454 		} else
455 			device_printf(dev, "no 387 emulator in kernel and no FPU!\n");
456 #endif
457 	}
458 	npxinit(__INITIAL_NPXCW__);
459 
460 #ifdef I586_CPU_XXX
461 	if (cpu_class == CPUCLASS_586 && npx_ex16 && npx_exists &&
462 	    timezero("i586_bzero()", i586_bzero) <
463 	    timezero("bzero()", bzero) * 4 / 5) {
464 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) {
465 			bcopy_vector = i586_bcopy;
466 			ovbcopy_vector = i586_bcopy;
467 		}
468 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_BZERO))
469 			bzero = i586_bzero;
470 		if (!(flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) {
471 			copyin_vector = i586_copyin;
472 			copyout_vector = i586_copyout;
473 		}
474 	}
475 #endif
476 
477 	return (0);		/* XXX unused */
478 }
479 
480 /*
481  * Initialize floating point unit.
482  */
483 void
484 npxinit(control)
485 	u_short control;
486 {
487 	struct save87 dummy;
488 
489 	if (!npx_exists)
490 		return;
491 	/*
492 	 * fninit has the same h/w bugs as fnsave.  Use the detoxified
493 	 * fnsave to throw away any junk in the fpu.  npxsave() initializes
494 	 * the fpu and sets npxproc = NULL as important side effects.
495 	 */
496 	npxsave(&dummy);
497 	stop_emulating();
498 	fldcw(&control);
499 	if (PCPU_GET(curpcb) != NULL)
500 		fnsave(&PCPU_GET(curpcb)->pcb_savefpu);
501 	start_emulating();
502 }
503 
504 /*
505  * Free coprocessor (if we have it).
506  */
507 void
508 npxexit(p)
509 	struct proc *p;
510 {
511 
512 	if (p == PCPU_GET(npxproc))
513 		npxsave(&PCPU_GET(curpcb)->pcb_savefpu);
514 #ifdef NPX_DEBUG
515 	if (npx_exists) {
516 		u_int	masked_exceptions;
517 
518 		masked_exceptions = PCPU_GET(curpcb)->pcb_savefpu.sv_env.en_cw
519 		    & PCPU_GET(curpcb)->pcb_savefpu.sv_env.en_sw & 0x7f;
520 		/*
521 		 * Log exceptions that would have trapped with the old
522 		 * control word (overflow, divide by 0, and invalid operand).
523 		 */
524 		if (masked_exceptions & 0x0d)
525 			log(LOG_ERR,
526 	"pid %d (%s) exited with masked floating point exceptions 0x%02x\n",
527 			    p->p_pid, p->p_comm, masked_exceptions);
528 	}
529 #endif
530 }
531 
532 /*
533  * The following mechanism is used to ensure that the FPE_... value
534  * that is passed as a trapcode to the signal handler of the user
535  * process does not have more than one bit set.
536  *
537  * Multiple bits may be set if the user process modifies the control
538  * word while a status word bit is already set.  While this is a sign
539  * of bad coding, we have no choise than to narrow them down to one
540  * bit, since we must not send a trapcode that is not exactly one of
541  * the FPE_ macros.
542  *
543  * The mechanism has a static table with 127 entries.  Each combination
544  * of the 7 FPU status word exception bits directly translates to a
545  * position in this table, where a single FPE_... value is stored.
546  * This FPE_... value stored there is considered the "most important"
547  * of the exception bits and will be sent as the signal code.  The
548  * precedence of the bits is based upon Intel Document "Numerical
549  * Applications", Chapter "Special Computational Situations".
550  *
551  * The macro to choose one of these values does these steps: 1) Throw
552  * away status word bits that cannot be masked.  2) Throw away the bits
553  * currently masked in the control word, assuming the user isn't
554  * interested in them anymore.  3) Reinsert status word bit 7 (stack
555  * fault) if it is set, which cannot be masked but must be presered.
556  * 4) Use the remaining bits to point into the trapcode table.
557  *
558  * The 6 maskable bits in order of their preference, as stated in the
559  * above referenced Intel manual:
560  * 1  Invalid operation (FP_X_INV)
561  * 1a   Stack underflow
562  * 1b   Stack overflow
563  * 1c   Operand of unsupported format
564  * 1d   SNaN operand.
565  * 2  QNaN operand (not an exception, irrelavant here)
566  * 3  Any other invalid-operation not mentioned above or zero divide
567  *      (FP_X_INV, FP_X_DZ)
568  * 4  Denormal operand (FP_X_DNML)
569  * 5  Numeric over/underflow (FP_X_OFL, FP_X_UFL)
570  * 6  Inexact result (FP_X_IMP)
571  */
572 static char fpetable[128] = {
573 	0,
574 	FPE_FLTINV,	/*  1 - INV */
575 	FPE_FLTUND,	/*  2 - DNML */
576 	FPE_FLTINV,	/*  3 - INV | DNML */
577 	FPE_FLTDIV,	/*  4 - DZ */
578 	FPE_FLTINV,	/*  5 - INV | DZ */
579 	FPE_FLTDIV,	/*  6 - DNML | DZ */
580 	FPE_FLTINV,	/*  7 - INV | DNML | DZ */
581 	FPE_FLTOVF,	/*  8 - OFL */
582 	FPE_FLTINV,	/*  9 - INV | OFL */
583 	FPE_FLTUND,	/*  A - DNML | OFL */
584 	FPE_FLTINV,	/*  B - INV | DNML | OFL */
585 	FPE_FLTDIV,	/*  C - DZ | OFL */
586 	FPE_FLTINV,	/*  D - INV | DZ | OFL */
587 	FPE_FLTDIV,	/*  E - DNML | DZ | OFL */
588 	FPE_FLTINV,	/*  F - INV | DNML | DZ | OFL */
589 	FPE_FLTUND,	/* 10 - UFL */
590 	FPE_FLTINV,	/* 11 - INV | UFL */
591 	FPE_FLTUND,	/* 12 - DNML | UFL */
592 	FPE_FLTINV,	/* 13 - INV | DNML | UFL */
593 	FPE_FLTDIV,	/* 14 - DZ | UFL */
594 	FPE_FLTINV,	/* 15 - INV | DZ | UFL */
595 	FPE_FLTDIV,	/* 16 - DNML | DZ | UFL */
596 	FPE_FLTINV,	/* 17 - INV | DNML | DZ | UFL */
597 	FPE_FLTOVF,	/* 18 - OFL | UFL */
598 	FPE_FLTINV,	/* 19 - INV | OFL | UFL */
599 	FPE_FLTUND,	/* 1A - DNML | OFL | UFL */
600 	FPE_FLTINV,	/* 1B - INV | DNML | OFL | UFL */
601 	FPE_FLTDIV,	/* 1C - DZ | OFL | UFL */
602 	FPE_FLTINV,	/* 1D - INV | DZ | OFL | UFL */
603 	FPE_FLTDIV,	/* 1E - DNML | DZ | OFL | UFL */
604 	FPE_FLTINV,	/* 1F - INV | DNML | DZ | OFL | UFL */
605 	FPE_FLTRES,	/* 20 - IMP */
606 	FPE_FLTINV,	/* 21 - INV | IMP */
607 	FPE_FLTUND,	/* 22 - DNML | IMP */
608 	FPE_FLTINV,	/* 23 - INV | DNML | IMP */
609 	FPE_FLTDIV,	/* 24 - DZ | IMP */
610 	FPE_FLTINV,	/* 25 - INV | DZ | IMP */
611 	FPE_FLTDIV,	/* 26 - DNML | DZ | IMP */
612 	FPE_FLTINV,	/* 27 - INV | DNML | DZ | IMP */
613 	FPE_FLTOVF,	/* 28 - OFL | IMP */
614 	FPE_FLTINV,	/* 29 - INV | OFL | IMP */
615 	FPE_FLTUND,	/* 2A - DNML | OFL | IMP */
616 	FPE_FLTINV,	/* 2B - INV | DNML | OFL | IMP */
617 	FPE_FLTDIV,	/* 2C - DZ | OFL | IMP */
618 	FPE_FLTINV,	/* 2D - INV | DZ | OFL | IMP */
619 	FPE_FLTDIV,	/* 2E - DNML | DZ | OFL | IMP */
620 	FPE_FLTINV,	/* 2F - INV | DNML | DZ | OFL | IMP */
621 	FPE_FLTUND,	/* 30 - UFL | IMP */
622 	FPE_FLTINV,	/* 31 - INV | UFL | IMP */
623 	FPE_FLTUND,	/* 32 - DNML | UFL | IMP */
624 	FPE_FLTINV,	/* 33 - INV | DNML | UFL | IMP */
625 	FPE_FLTDIV,	/* 34 - DZ | UFL | IMP */
626 	FPE_FLTINV,	/* 35 - INV | DZ | UFL | IMP */
627 	FPE_FLTDIV,	/* 36 - DNML | DZ | UFL | IMP */
628 	FPE_FLTINV,	/* 37 - INV | DNML | DZ | UFL | IMP */
629 	FPE_FLTOVF,	/* 38 - OFL | UFL | IMP */
630 	FPE_FLTINV,	/* 39 - INV | OFL | UFL | IMP */
631 	FPE_FLTUND,	/* 3A - DNML | OFL | UFL | IMP */
632 	FPE_FLTINV,	/* 3B - INV | DNML | OFL | UFL | IMP */
633 	FPE_FLTDIV,	/* 3C - DZ | OFL | UFL | IMP */
634 	FPE_FLTINV,	/* 3D - INV | DZ | OFL | UFL | IMP */
635 	FPE_FLTDIV,	/* 3E - DNML | DZ | OFL | UFL | IMP */
636 	FPE_FLTINV,	/* 3F - INV | DNML | DZ | OFL | UFL | IMP */
637 	FPE_FLTSUB,	/* 40 - STK */
638 	FPE_FLTSUB,	/* 41 - INV | STK */
639 	FPE_FLTUND,	/* 42 - DNML | STK */
640 	FPE_FLTSUB,	/* 43 - INV | DNML | STK */
641 	FPE_FLTDIV,	/* 44 - DZ | STK */
642 	FPE_FLTSUB,	/* 45 - INV | DZ | STK */
643 	FPE_FLTDIV,	/* 46 - DNML | DZ | STK */
644 	FPE_FLTSUB,	/* 47 - INV | DNML | DZ | STK */
645 	FPE_FLTOVF,	/* 48 - OFL | STK */
646 	FPE_FLTSUB,	/* 49 - INV | OFL | STK */
647 	FPE_FLTUND,	/* 4A - DNML | OFL | STK */
648 	FPE_FLTSUB,	/* 4B - INV | DNML | OFL | STK */
649 	FPE_FLTDIV,	/* 4C - DZ | OFL | STK */
650 	FPE_FLTSUB,	/* 4D - INV | DZ | OFL | STK */
651 	FPE_FLTDIV,	/* 4E - DNML | DZ | OFL | STK */
652 	FPE_FLTSUB,	/* 4F - INV | DNML | DZ | OFL | STK */
653 	FPE_FLTUND,	/* 50 - UFL | STK */
654 	FPE_FLTSUB,	/* 51 - INV | UFL | STK */
655 	FPE_FLTUND,	/* 52 - DNML | UFL | STK */
656 	FPE_FLTSUB,	/* 53 - INV | DNML | UFL | STK */
657 	FPE_FLTDIV,	/* 54 - DZ | UFL | STK */
658 	FPE_FLTSUB,	/* 55 - INV | DZ | UFL | STK */
659 	FPE_FLTDIV,	/* 56 - DNML | DZ | UFL | STK */
660 	FPE_FLTSUB,	/* 57 - INV | DNML | DZ | UFL | STK */
661 	FPE_FLTOVF,	/* 58 - OFL | UFL | STK */
662 	FPE_FLTSUB,	/* 59 - INV | OFL | UFL | STK */
663 	FPE_FLTUND,	/* 5A - DNML | OFL | UFL | STK */
664 	FPE_FLTSUB,	/* 5B - INV | DNML | OFL | UFL | STK */
665 	FPE_FLTDIV,	/* 5C - DZ | OFL | UFL | STK */
666 	FPE_FLTSUB,	/* 5D - INV | DZ | OFL | UFL | STK */
667 	FPE_FLTDIV,	/* 5E - DNML | DZ | OFL | UFL | STK */
668 	FPE_FLTSUB,	/* 5F - INV | DNML | DZ | OFL | UFL | STK */
669 	FPE_FLTRES,	/* 60 - IMP | STK */
670 	FPE_FLTSUB,	/* 61 - INV | IMP | STK */
671 	FPE_FLTUND,	/* 62 - DNML | IMP | STK */
672 	FPE_FLTSUB,	/* 63 - INV | DNML | IMP | STK */
673 	FPE_FLTDIV,	/* 64 - DZ | IMP | STK */
674 	FPE_FLTSUB,	/* 65 - INV | DZ | IMP | STK */
675 	FPE_FLTDIV,	/* 66 - DNML | DZ | IMP | STK */
676 	FPE_FLTSUB,	/* 67 - INV | DNML | DZ | IMP | STK */
677 	FPE_FLTOVF,	/* 68 - OFL | IMP | STK */
678 	FPE_FLTSUB,	/* 69 - INV | OFL | IMP | STK */
679 	FPE_FLTUND,	/* 6A - DNML | OFL | IMP | STK */
680 	FPE_FLTSUB,	/* 6B - INV | DNML | OFL | IMP | STK */
681 	FPE_FLTDIV,	/* 6C - DZ | OFL | IMP | STK */
682 	FPE_FLTSUB,	/* 6D - INV | DZ | OFL | IMP | STK */
683 	FPE_FLTDIV,	/* 6E - DNML | DZ | OFL | IMP | STK */
684 	FPE_FLTSUB,	/* 6F - INV | DNML | DZ | OFL | IMP | STK */
685 	FPE_FLTUND,	/* 70 - UFL | IMP | STK */
686 	FPE_FLTSUB,	/* 71 - INV | UFL | IMP | STK */
687 	FPE_FLTUND,	/* 72 - DNML | UFL | IMP | STK */
688 	FPE_FLTSUB,	/* 73 - INV | DNML | UFL | IMP | STK */
689 	FPE_FLTDIV,	/* 74 - DZ | UFL | IMP | STK */
690 	FPE_FLTSUB,	/* 75 - INV | DZ | UFL | IMP | STK */
691 	FPE_FLTDIV,	/* 76 - DNML | DZ | UFL | IMP | STK */
692 	FPE_FLTSUB,	/* 77 - INV | DNML | DZ | UFL | IMP | STK */
693 	FPE_FLTOVF,	/* 78 - OFL | UFL | IMP | STK */
694 	FPE_FLTSUB,	/* 79 - INV | OFL | UFL | IMP | STK */
695 	FPE_FLTUND,	/* 7A - DNML | OFL | UFL | IMP | STK */
696 	FPE_FLTSUB,	/* 7B - INV | DNML | OFL | UFL | IMP | STK */
697 	FPE_FLTDIV,	/* 7C - DZ | OFL | UFL | IMP | STK */
698 	FPE_FLTSUB,	/* 7D - INV | DZ | OFL | UFL | IMP | STK */
699 	FPE_FLTDIV,	/* 7E - DNML | DZ | OFL | UFL | IMP | STK */
700 	FPE_FLTSUB,	/* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */
701 };
702 
703 /*
704  * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
705  *
706  * Clearing exceptions is necessary mainly to avoid IRQ13 bugs.  We now
707  * depend on longjmp() restoring a usable state.  Restoring the state
708  * or examining it might fail if we didn't clear exceptions.
709  *
710  * The error code chosen will be one of the FPE_... macros. It will be
711  * sent as the second argument to old BSD-style signal handlers and as
712  * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers.
713  *
714  * XXX the FP state is not preserved across signal handlers.  So signal
715  * handlers cannot afford to do FP unless they preserve the state or
716  * longjmp() out.  Both preserving the state and longjmp()ing may be
717  * destroyed by IRQ13 bugs.  Clearing FP exceptions is not an acceptable
718  * solution for signals other than SIGFPE.
719  */
720 void
721 npx_intr(dummy)
722 	void *dummy;
723 {
724 	int code;
725 	u_short control;
726 	struct intrframe *frame;
727 
728 	if (!npx_exists) {
729 		printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
730 		       PCPU_GET(npxproc), curproc, npx_exists);
731 		panic("npxintr from nowhere");
732 	}
733 	outb(0xf0, 0);
734 	mtx_lock_spin(&sched_lock);
735 	if (PCPU_GET(npxproc) != curproc) {
736 		/*
737 		 * Interrupt handling (for this or another interrupt) has
738 		 * switched npxproc from underneath us before we managed
739 		 * to handle this interrupt.  Just ignore this interrupt.
740 		 * Control will eventually return to the instruction that
741 		 * caused it and it will repeat.  In the npx_ex16 case,
742 		 * then we will eventually (usually soon) win the race.
743 		 * In the npx_irq13 case, we will always lose the race
744 		 * because we have switched to the IRQ13 thread.  This will
745 		 * be fixed later.
746 		 */
747 		mtx_unlock_spin(&sched_lock);
748 		return;
749 	}
750 	fnstsw(&PCPU_GET(curpcb)->pcb_savefpu.sv_ex_sw);
751 	fnstcw(&control);
752 	fnclex();
753 	mtx_unlock_spin(&sched_lock);
754 
755 	/*
756 	 * Pass exception to process.
757 	 */
758 	mtx_lock(&Giant);
759 	frame = (struct intrframe *)&dummy;	/* XXX */
760 	if ((ISPL(frame->if_cs) == SEL_UPL) || (frame->if_eflags & PSL_VM)) {
761 		/*
762 		 * Interrupt is essentially a trap, so we can afford to call
763 		 * the SIGFPE handler (if any) as soon as the interrupt
764 		 * returns.
765 		 *
766 		 * XXX little or nothing is gained from this, and plenty is
767 		 * lost - the interrupt frame has to contain the trap frame
768 		 * (this is otherwise only necessary for the rescheduling trap
769 		 * in doreti, and the frame for that could easily be set up
770 		 * just before it is used).
771 		 */
772 		curproc->p_md.md_regs = INTR_TO_TRAPFRAME(frame);
773 		/*
774 		 * Encode the appropriate code for detailed information on
775 		 * this exception.
776 		 */
777 		code =
778 		    fpetable[(PCPU_GET(curpcb)->pcb_savefpu.sv_ex_sw & ~control & 0x3f) |
779 			(PCPU_GET(curpcb)->pcb_savefpu.sv_ex_sw & 0x40)];
780 		trapsignal(curproc, SIGFPE, code);
781 	} else {
782 		/*
783 		 * Nested interrupt.  These losers occur when:
784 		 *	o an IRQ13 is bogusly generated at a bogus time, e.g.:
785 		 *		o immediately after an fnsave or frstor of an
786 		 *		  error state.
787 		 *		o a couple of 386 instructions after
788 		 *		  "fstpl _memvar" causes a stack overflow.
789 		 *	  These are especially nasty when combined with a
790 		 *	  trace trap.
791 		 *	o an IRQ13 occurs at the same time as another higher-
792 		 *	  priority interrupt.
793 		 *
794 		 * Treat them like a true async interrupt.
795 		 */
796 		PROC_LOCK(curproc);
797 		psignal(curproc, SIGFPE);
798 		PROC_UNLOCK(curproc);
799 	}
800 	mtx_unlock(&Giant);
801 }
802 
803 /*
804  * Implement device not available (DNA) exception
805  *
806  * It would be better to switch FP context here (if curproc != npxproc)
807  * and not necessarily for every context switch, but it is too hard to
808  * access foreign pcb's.
809  */
810 int
811 npxdna()
812 {
813 	critical_t s;
814 
815 	if (!npx_exists)
816 		return (0);
817 	if (PCPU_GET(npxproc) != NULL) {
818 		printf("npxdna: npxproc = %p, curproc = %p\n",
819 		       PCPU_GET(npxproc), curproc);
820 		panic("npxdna");
821 	}
822 	s = critical_enter();
823 	stop_emulating();
824 	/*
825 	 * Record new context early in case frstor causes an IRQ13.
826 	 */
827 	PCPU_SET(npxproc, CURPROC);
828 	PCPU_GET(curpcb)->pcb_savefpu.sv_ex_sw = 0;
829 	/*
830 	 * The following frstor may cause an IRQ13 when the state being
831 	 * restored has a pending error.  The error will appear to have been
832 	 * triggered by the current (npx) user instruction even when that
833 	 * instruction is a no-wait instruction that should not trigger an
834 	 * error (e.g., fnclex).  On at least one 486 system all of the
835 	 * no-wait instructions are broken the same as frstor, so our
836 	 * treatment does not amplify the breakage.  On at least one
837 	 * 386/Cyrix 387 system, fnclex works correctly while frstor and
838 	 * fnsave are broken, so our treatment breaks fnclex if it is the
839 	 * first FPU instruction after a context switch.
840 	 */
841 	frstor(&PCPU_GET(curpcb)->pcb_savefpu);
842 	critical_exit(s);
843 
844 	return (1);
845 }
846 
847 /*
848  * Wrapper for fnsave instruction to handle h/w bugs.  If there is an error
849  * pending, then fnsave generates a bogus IRQ13 on some systems.  Force
850  * any IRQ13 to be handled immediately, and then ignore it.  This routine is
851  * often called at splhigh so it must not use many system services.  In
852  * particular, it's much easier to install a special handler than to
853  * guarantee that it's safe to use npxintr() and its supporting code.
854  */
855 void
856 npxsave(addr)
857 	struct save87 *addr;
858 {
859 #ifdef SMP
860 
861 	stop_emulating();
862 	fnsave(addr);
863 	/* fnop(); */
864 	start_emulating();
865 	PCPU_SET(npxproc, NULL);
866 
867 #else /* SMP */
868 
869 	critical_t savecrit;
870 	u_char	icu1_mask;
871 	u_char	icu2_mask;
872 	u_char	old_icu1_mask;
873 	u_char	old_icu2_mask;
874 	struct gate_descriptor	save_idt_npxintr;
875 
876 	savecrit = critical_enter();
877 	old_icu1_mask = inb(IO_ICU1 + 1);
878 	old_icu2_mask = inb(IO_ICU2 + 1);
879 	save_idt_npxintr = idt[npx_intrno];
880 	outb(IO_ICU1 + 1, old_icu1_mask & ~(IRQ_SLAVE | npx0_imask));
881 	outb(IO_ICU2 + 1, old_icu2_mask & ~(npx0_imask >> 8));
882 	idt[npx_intrno] = npx_idt_probeintr;
883 	critical_exit(savecrit);
884 	stop_emulating();
885 	fnsave(addr);
886 	fnop();
887 	start_emulating();
888 	savecrit = critical_enter();
889 	PCPU_SET(npxproc, NULL);
890 	icu1_mask = inb(IO_ICU1 + 1);	/* masks may have changed */
891 	icu2_mask = inb(IO_ICU2 + 1);
892 	outb(IO_ICU1 + 1,
893 	     (icu1_mask & ~npx0_imask) | (old_icu1_mask & npx0_imask));
894 	outb(IO_ICU2 + 1,
895 	     (icu2_mask & ~(npx0_imask >> 8))
896 	     | (old_icu2_mask & (npx0_imask >> 8)));
897 	idt[npx_intrno] = save_idt_npxintr;
898 	critical_exit(savecrit);		/* back to previous state */
899 
900 #endif /* SMP */
901 }
902 
903 #ifdef I586_CPU
904 static long
905 timezero(funcname, func)
906 	const char *funcname;
907 	void (*func) __P((void *buf, size_t len));
908 
909 {
910 	void *buf;
911 #define	BUFSIZE		1048576
912 	long usec;
913 	struct timeval finish, start;
914 
915 	buf = malloc(BUFSIZE, M_TEMP, M_NOWAIT);
916 	if (buf == NULL)
917 		return (BUFSIZE);
918 	microtime(&start);
919 	(*func)(buf, BUFSIZE);
920 	microtime(&finish);
921 	usec = 1000000 * (finish.tv_sec - start.tv_sec) +
922 	    finish.tv_usec - start.tv_usec;
923 	if (usec <= 0)
924 		usec = 1;
925 	if (bootverbose)
926 		printf("%s bandwidth = %lu kBps\n", funcname,
927 		    (u_int32_t)(((BUFSIZE >> 10) * 1000000) / usec));
928 	free(buf, M_TEMP);
929 	return (usec);
930 }
931 #endif /* I586_CPU */
932 
933 static device_method_t npx_methods[] = {
934 	/* Device interface */
935 	DEVMETHOD(device_identify,	npx_identify),
936 	DEVMETHOD(device_probe,		npx_probe),
937 	DEVMETHOD(device_attach,	npx_attach),
938 	DEVMETHOD(device_detach,	bus_generic_detach),
939 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
940 	DEVMETHOD(device_suspend,	bus_generic_suspend),
941 	DEVMETHOD(device_resume,	bus_generic_resume),
942 
943 	{ 0, 0 }
944 };
945 
946 static driver_t npx_driver = {
947 	"npx",
948 	npx_methods,
949 	1,			/* no softc */
950 };
951 
952 static devclass_t npx_devclass;
953 
954 /*
955  * We prefer to attach to the root nexus so that the usual case (exception 16)
956  * doesn't describe the processor as being `on isa'.
957  */
958 DRIVER_MODULE(npx, nexus, npx_driver, npx_devclass, 0, 0);
959 
960 /*
961  * This sucks up the legacy ISA support assignments from PNPBIOS.
962  */
963 static struct isa_pnp_id npxisa_ids[] = {
964 	{ 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
965 	{ 0 }
966 };
967 
968 static int
969 npxisa_probe(device_t dev)
970 {
971 	int result;
972 	if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, npxisa_ids)) <= 0) {
973 		device_quiet(dev);
974 	}
975 	return(result);
976 }
977 
978 static int
979 npxisa_attach(device_t dev)
980 {
981 	return (0);
982 }
983 
984 static device_method_t npxisa_methods[] = {
985 	/* Device interface */
986 	DEVMETHOD(device_probe,		npxisa_probe),
987 	DEVMETHOD(device_attach,	npxisa_attach),
988 	DEVMETHOD(device_detach,	bus_generic_detach),
989 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
990 	DEVMETHOD(device_suspend,	bus_generic_suspend),
991 	DEVMETHOD(device_resume,	bus_generic_resume),
992 
993 	{ 0, 0 }
994 };
995 
996 static driver_t npxisa_driver = {
997 	"npxisa",
998 	npxisa_methods,
999 	1,			/* no softc */
1000 };
1001 
1002 static devclass_t npxisa_devclass;
1003 
1004 DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0);
1005 
1006