npx.c revision 27555
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 *	$Id: npx.c,v 1.47 1997/07/17 02:09:25 peter Exp $
36 */
37
38#include "npx.h"
39#if NNPX > 0
40
41#include "opt_cpu.h"
42#include "opt_math_emulate.h"
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/kernel.h>
47#include <sys/sysctl.h>
48#include <sys/conf.h>
49#include <sys/proc.h>
50#ifdef NPX_DEBUG
51#include <sys/syslog.h>
52#endif
53#include <sys/signalvar.h>
54
55#include <machine/asmacros.h>
56#include <machine/cpu.h>
57#include <machine/ipl.h>
58#include <machine/md_var.h>
59#include <machine/pcb.h>
60#include <machine/clock.h>
61#include <machine/specialreg.h>
62#if defined(APIC_IO)
63#include <machine/smp.h>
64#include <machine/apic.h>
65#include <machine/mpapic.h>
66#endif /* APIC_IO */
67
68#include <i386/isa/icu.h>
69#include <i386/isa/isa_device.h>
70#include <i386/isa/intr_machdep.h>
71#include <i386/isa/isa.h>
72
73/*
74 * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
75 */
76
77/* Configuration flags. */
78#define	NPX_DISABLE_I586_OPTIMIZED_BCOPY	(1 << 0)
79#define	NPX_DISABLE_I586_OPTIMIZED_BZERO	(1 << 1)
80#define	NPX_DISABLE_I586_OPTIMIZED_COPYIO	(1 << 2)
81
82/* XXX - should be in header file. */
83extern void (*bcopy_vector) __P((const void *from, void *to, size_t len));
84extern void (*ovbcopy_vector) __P((const void *from, void *to, size_t len));
85extern int (*copyin_vector) __P((const void *udaddr, void *kaddr, size_t len));
86extern int (*copyout_vector) __P((const void *kaddr, void *udaddr, size_t len));
87
88void	i586_bcopy __P((const void *from, void *to, size_t len));
89void	i586_bzero __P((void *buf, size_t len));
90int	i586_copyin __P((const void *udaddr, void *kaddr, size_t len));
91int	i586_copyout __P((const void *kaddr, void *udaddr, size_t len));
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	fnop()			__asm("fnop")
99#define	fnsave(addr)		__asm("fnsave %0" : "=m" (*(addr)))
100#define	fnstcw(addr)		__asm("fnstcw %0" : "=m" (*(addr)))
101#define	fnstsw(addr)		__asm("fnstsw %0" : "=m" (*(addr)))
102#define	fp_divide_by_0()	__asm("fldz; fld1; fdiv %st,%st(1); fnop")
103#define	frstor(addr)		__asm("frstor %0" : : "m" (*(addr)))
104#define	start_emulating()	__asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
105				      : : "n" (CR0_TS) : "ax")
106#define	stop_emulating()	__asm("clts")
107
108#else	/* not __GNUC__ */
109
110void	fldcw		__P((caddr_t addr));
111void	fnclex		__P((void));
112void	fninit		__P((void));
113void	fnop		__P((void));
114void	fnsave		__P((caddr_t addr));
115void	fnstcw		__P((caddr_t addr));
116void	fnstsw		__P((caddr_t addr));
117void	fp_divide_by_0	__P((void));
118void	frstor		__P((caddr_t addr));
119void	start_emulating	__P((void));
120void	stop_emulating	__P((void));
121
122#endif	/* __GNUC__ */
123
124typedef u_char bool_t;
125
126static	int	npxattach	__P((struct isa_device *dvp));
127static	int	npxprobe	__P((struct isa_device *dvp));
128static	int	npxprobe1	__P((struct isa_device *dvp));
129
130struct	isa_driver npxdriver = {
131	npxprobe, npxattach, "npx",
132};
133
134int	hw_float;		/* XXX currently just alias for npx_exists */
135
136SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
137	CTLFLAG_RD, &hw_float, 0,
138	"Floatingpoint instructions executed in hardware");
139
140static u_int	npx0_imask = SWI_CLOCK_MASK;
141
142#ifndef SMP	/* XXX per-cpu on smp */
143struct proc	*npxproc;
144#endif
145
146static	bool_t			npx_ex16;
147static	bool_t			npx_exists;
148static	struct gate_descriptor	npx_idt_probeintr;
149static	int			npx_intrno;
150static	volatile u_int		npx_intrs_while_probing;
151static	bool_t			npx_irq13;
152static	volatile u_int		npx_traps_while_probing;
153
154/*
155 * Special interrupt handlers.  Someday intr0-intr15 will be used to count
156 * interrupts.  We'll still need a special exception 16 handler.  The busy
157 * latch stuff in probeintr() can be moved to npxprobe().
158 */
159inthand_t probeintr;
160
161#if defined(APIC_IO)
162
163asm
164("
165	.text
166	.p2align 2,0x90
167" __XSTRING(CNAME(probeintr)) ":
168	ss
169	incl	" __XSTRING(CNAME(npx_intrs_while_probing)) "
170	pushl	%eax
171	movl	$lapic_eoi,%eax		# EOI to local APIC
172	movl	$0,(%eax)		# movl $0, APIC_EOI(%eax)
173	movb	$0,%al
174	outb	%al,$0xf0		# clear BUSY# latch
175	popl	%eax
176	iret
177");
178
179#else
180
181asm
182("
183	.text
184	.p2align 2,0x90
185" __XSTRING(CNAME(probeintr)) ":
186	ss
187	incl	" __XSTRING(CNAME(npx_intrs_while_probing)) "
188	pushl	%eax
189	movb	$0x20,%al	# EOI (asm in strings loses cpp features)
190	outb	%al,$0xa0	# IO_ICU2
191	outb	%al,$0x20	# IO_ICU1
192	movb	$0,%al
193	outb	%al,$0xf0	# clear BUSY# latch
194	popl	%eax
195	iret
196");
197
198#endif /* APIC_IO */
199
200inthand_t probetrap;
201asm
202("
203	.text
204	.p2align 2,0x90
205" __XSTRING(CNAME(probetrap)) ":
206	ss
207	incl	" __XSTRING(CNAME(npx_traps_while_probing)) "
208	fnclex
209	iret
210");
211
212/*
213 * Probe routine.  Initialize cr0 to give correct behaviour for [f]wait
214 * whether the device exists or not (XXX should be elsewhere).  Set flags
215 * to tell npxattach() what to do.  Modify device struct if npx doesn't
216 * need to use interrupts.  Return 1 if device exists.
217 */
218static int
219npxprobe(dvp)
220	struct isa_device *dvp;
221{
222	int	result;
223	u_long	save_eflags;
224#if defined(APIC_IO)
225	u_int	save_apic_mask;
226#else
227	u_char	save_icu1_mask;
228	u_char	save_icu2_mask;
229#endif /* APIC_IO */
230	struct	gate_descriptor save_idt_npxintr;
231	struct	gate_descriptor save_idt_npxtrap;
232	/*
233	 * This routine is now just a wrapper for npxprobe1(), to install
234	 * special npx interrupt and trap handlers, to enable npx interrupts
235	 * and to disable other interrupts.  Someday isa_configure() will
236	 * install suitable handlers and run with interrupts enabled so we
237	 * won't need to do so much here.
238	 */
239	npx_intrno = NRSVIDT + ffs(dvp->id_irq) - 1;
240	save_eflags = read_eflags();
241	disable_intr();
242#if defined(APIC_IO)
243	save_apic_mask = INTRGET();
244#else
245	save_icu1_mask = inb(IO_ICU1 + 1);
246	save_icu2_mask = inb(IO_ICU2 + 1);
247#endif /* APIC_IO */
248	save_idt_npxintr = idt[npx_intrno];
249	save_idt_npxtrap = idt[16];
250#if defined(APIC_IO)
251	INTRSET( ~dvp->id_irq );
252#else
253	outb(IO_ICU1 + 1, ~(IRQ_SLAVE | dvp->id_irq));
254	outb(IO_ICU2 + 1, ~(dvp->id_irq >> 8));
255#endif /* APIC_IO */
256	setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
257	setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
258	npx_idt_probeintr = idt[npx_intrno];
259	enable_intr();
260	result = npxprobe1(dvp);
261	disable_intr();
262#if defined(APIC_IO)
263	INTRSET( save_apic_mask );
264#else
265	outb(IO_ICU1 + 1, save_icu1_mask);
266	outb(IO_ICU2 + 1, save_icu2_mask);
267#endif /* APIC_IO */
268	idt[npx_intrno] = save_idt_npxintr;
269	idt[16] = save_idt_npxtrap;
270	write_eflags(save_eflags);
271	return (result);
272}
273
274static int
275npxprobe1(dvp)
276	struct isa_device *dvp;
277{
278	u_short control;
279	u_short status;
280
281	/*
282	 * Partially reset the coprocessor, if any.  Some BIOS's don't reset
283	 * it after a warm boot.
284	 */
285	outb(0xf1, 0);		/* full reset on some systems, NOP on others */
286	outb(0xf0, 0);		/* clear BUSY# latch */
287	/*
288	 * Prepare to trap all ESC (i.e., NPX) instructions and all WAIT
289	 * instructions.  We must set the CR0_MP bit and use the CR0_TS
290	 * bit to control the trap, because setting the CR0_EM bit does
291	 * not cause WAIT instructions to trap.  It's important to trap
292	 * WAIT instructions - otherwise the "wait" variants of no-wait
293	 * control instructions would degenerate to the "no-wait" variants
294	 * after FP context switches but work correctly otherwise.  It's
295	 * particularly important to trap WAITs when there is no NPX -
296	 * otherwise the "wait" variants would always degenerate.
297	 *
298	 * Try setting CR0_NE to get correct error reporting on 486DX's.
299	 * Setting it should fail or do nothing on lesser processors.
300	 */
301	load_cr0(rcr0() | CR0_MP | CR0_NE);
302	/*
303	 * But don't trap while we're probing.
304	 */
305	stop_emulating();
306	/*
307	 * Finish resetting the coprocessor, if any.  If there is an error
308	 * pending, then we may get a bogus IRQ13, but probeintr() will handle
309	 * it OK.  Bogus halts have never been observed, but we enabled
310	 * IRQ13 and cleared the BUSY# latch early to handle them anyway.
311	 */
312	fninit();
313	/*
314	 * Don't use fwait here because it might hang.
315	 * Don't use fnop here because it usually hangs if there is no FPU.
316	 */
317	DELAY(1000);		/* wait for any IRQ13 */
318#ifdef DIAGNOSTIC
319	if (npx_intrs_while_probing != 0)
320		printf("fninit caused %u bogus npx interrupt(s)\n",
321		       npx_intrs_while_probing);
322	if (npx_traps_while_probing != 0)
323		printf("fninit caused %u bogus npx trap(s)\n",
324		       npx_traps_while_probing);
325#endif
326	/*
327	 * Check for a status of mostly zero.
328	 */
329	status = 0x5a5a;
330	fnstsw(&status);
331	if ((status & 0xb8ff) == 0) {
332		/*
333		 * Good, now check for a proper control word.
334		 */
335		control = 0x5a5a;
336		fnstcw(&control);
337		if ((control & 0x1f3f) == 0x033f) {
338			hw_float = npx_exists = 1;
339			/*
340			 * We have an npx, now divide by 0 to see if exception
341			 * 16 works.
342			 */
343			control &= ~(1 << 2);	/* enable divide by 0 trap */
344			fldcw(&control);
345			npx_traps_while_probing = npx_intrs_while_probing = 0;
346			fp_divide_by_0();
347			if (npx_traps_while_probing != 0) {
348				/*
349				 * Good, exception 16 works.
350				 */
351				npx_ex16 = 1;
352				dvp->id_irq = 0;	/* zap the interrupt */
353				/*
354				 * special return value to flag that we do not
355				 * actually use any I/O registers
356				 */
357				return (-1);
358			}
359			if (npx_intrs_while_probing != 0) {
360				/*
361				 * Bad, we are stuck with IRQ13.
362				 */
363				npx_irq13 = 1;
364				/*
365				 * npxattach would be too late to set npx0_imask.
366				 */
367				npx0_imask |= dvp->id_irq;
368				return (IO_NPXSIZE);
369			}
370			/*
371			 * Worse, even IRQ13 is broken.  Use emulator.
372			 */
373		}
374	}
375	/*
376	 * Probe failed, but we want to get to npxattach to initialize the
377	 * emulator and say that it has been installed.  XXX handle devices
378	 * that aren't really devices better.
379	 */
380	dvp->id_irq = 0;
381	/*
382	 * special return value to flag that we do not
383	 * actually use any I/O registers
384	 */
385	return (-1);
386}
387
388/*
389 * Attach routine - announce which it is, and wire into system
390 */
391int
392npxattach(dvp)
393	struct isa_device *dvp;
394{
395	/* The caller has printed "irq 13" for the npx_irq13 case. */
396	if (!npx_irq13) {
397		printf("npx%d: ", dvp->id_unit);
398		if (npx_ex16)
399			printf("INT 16 interface\n");
400#if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE)
401		else if (npx_exists) {
402			printf("error reporting broken; using 387 emulator\n");
403			hw_float = npx_exists = 0;
404		} else
405			printf("387 emulator\n");
406#else
407		else
408			printf("no 387 emulator in kernel!\n");
409#endif
410	}
411	npxinit(__INITIAL_NPXCW__);
412
413#if defined(I586_CPU)
414	if (cpu_class == CPUCLASS_586 && npx_ex16) {
415		if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) {
416			bcopy_vector = i586_bcopy;
417			ovbcopy_vector = i586_bcopy;
418		}
419		if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BZERO))
420			bzero = i586_bzero;
421		if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) {
422			copyin_vector = i586_copyin;
423			copyout_vector = i586_copyout;
424		}
425	}
426#endif
427
428	return (1);		/* XXX unused */
429}
430
431/*
432 * Initialize floating point unit.
433 */
434void
435npxinit(control)
436	u_short control;
437{
438	struct save87 dummy;
439
440	if (!npx_exists)
441		return;
442	/*
443	 * fninit has the same h/w bugs as fnsave.  Use the detoxified
444	 * fnsave to throw away any junk in the fpu.  npxsave() initializes
445	 * the fpu and sets npxproc = NULL as important side effects.
446	 */
447	npxsave(&dummy);
448	stop_emulating();
449	fldcw(&control);
450	if (curpcb != NULL)
451		fnsave(&curpcb->pcb_savefpu);
452	start_emulating();
453}
454
455/*
456 * Free coprocessor (if we have it).
457 */
458void
459npxexit(p)
460	struct proc *p;
461{
462
463	if (p == npxproc)
464		npxsave(&curpcb->pcb_savefpu);
465#ifdef NPX_DEBUG
466	if (npx_exists) {
467		u_int	masked_exceptions;
468
469		masked_exceptions = curpcb->pcb_savefpu.sv_env.en_cw
470				    & curpcb->pcb_savefpu.sv_env.en_sw & 0x7f;
471		/*
472		 * Log exceptions that would have trapped with the old
473		 * control word (overflow, divide by 0, and invalid operand).
474		 */
475		if (masked_exceptions & 0x0d)
476			log(LOG_ERR,
477	"pid %d (%s) exited with masked floating point exceptions 0x%02x\n",
478			    p->p_pid, p->p_comm, masked_exceptions);
479	}
480#endif
481}
482
483/*
484 * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
485 *
486 * Clearing exceptions is necessary mainly to avoid IRQ13 bugs.  We now
487 * depend on longjmp() restoring a usable state.  Restoring the state
488 * or examining it might fail if we didn't clear exceptions.
489 *
490 * XXX there is no standard way to tell SIGFPE handlers about the error
491 * state.  The old interface:
492 *
493 *	void handler(int sig, int code, struct sigcontext *scp);
494 *
495 * is broken because it is non-ANSI and because the FP state is not in
496 * struct sigcontext.
497 *
498 * XXX the FP state is not preserved across signal handlers.  So signal
499 * handlers cannot afford to do FP unless they preserve the state or
500 * longjmp() out.  Both preserving the state and longjmp()ing may be
501 * destroyed by IRQ13 bugs.  Clearing FP exceptions is not an acceptable
502 * solution for signals other than SIGFPE.
503 */
504void
505npxintr(unit)
506	int unit;
507{
508	int code;
509	struct intrframe *frame;
510
511	if (npxproc == NULL || !npx_exists) {
512		printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
513		       npxproc, curproc, npx_exists);
514		panic("npxintr from nowhere");
515	}
516	if (npxproc != curproc) {
517		printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
518		       npxproc, curproc, npx_exists);
519		panic("npxintr from non-current process");
520	}
521
522	outb(0xf0, 0);
523	fnstsw(&curpcb->pcb_savefpu.sv_ex_sw);
524	fnclex();
525	fnop();
526
527	/*
528	 * Pass exception to process.
529	 */
530	frame = (struct intrframe *)&unit;	/* XXX */
531	if (ISPL(frame->if_cs) == SEL_UPL) {
532		/*
533		 * Interrupt is essentially a trap, so we can afford to call
534		 * the SIGFPE handler (if any) as soon as the interrupt
535		 * returns.
536		 *
537		 * XXX little or nothing is gained from this, and plenty is
538		 * lost - the interrupt frame has to contain the trap frame
539		 * (this is otherwise only necessary for the rescheduling trap
540		 * in doreti, and the frame for that could easily be set up
541		 * just before it is used).
542		 */
543		curproc->p_md.md_regs = (struct trapframe *)&frame->if_es;
544#ifdef notyet
545		/*
546		 * Encode the appropriate code for detailed information on
547		 * this exception.
548		 */
549		code = XXX_ENCODE(curpcb->pcb_savefpu.sv_ex_sw);
550#else
551		code = 0;	/* XXX */
552#endif
553		trapsignal(curproc, SIGFPE, code);
554	} else {
555		/*
556		 * Nested interrupt.  These losers occur when:
557		 *	o an IRQ13 is bogusly generated at a bogus time, e.g.:
558		 *		o immediately after an fnsave or frstor of an
559		 *		  error state.
560		 *		o a couple of 386 instructions after
561		 *		  "fstpl _memvar" causes a stack overflow.
562		 *	  These are especially nasty when combined with a
563		 *	  trace trap.
564		 *	o an IRQ13 occurs at the same time as another higher-
565		 *	  priority interrupt.
566		 *
567		 * Treat them like a true async interrupt.
568		 */
569		psignal(curproc, SIGFPE);
570	}
571}
572
573/*
574 * Implement device not available (DNA) exception
575 *
576 * It would be better to switch FP context here (if curproc != npxproc)
577 * and not necessarily for every context switch, but it is too hard to
578 * access foreign pcb's.
579 */
580int
581npxdna()
582{
583	if (!npx_exists)
584		return (0);
585	if (npxproc != NULL) {
586		printf("npxdna: npxproc = %p, curproc = %p\n",
587		       npxproc, curproc);
588		panic("npxdna");
589	}
590	stop_emulating();
591	/*
592	 * Record new context early in case frstor causes an IRQ13.
593	 */
594	npxproc = curproc;
595	curpcb->pcb_savefpu.sv_ex_sw = 0;
596	/*
597	 * The following frstor may cause an IRQ13 when the state being
598	 * restored has a pending error.  The error will appear to have been
599	 * triggered by the current (npx) user instruction even when that
600	 * instruction is a no-wait instruction that should not trigger an
601	 * error (e.g., fnclex).  On at least one 486 system all of the
602	 * no-wait instructions are broken the same as frstor, so our
603	 * treatment does not amplify the breakage.  On at least one
604	 * 386/Cyrix 387 system, fnclex works correctly while frstor and
605	 * fnsave are broken, so our treatment breaks fnclex if it is the
606	 * first FPU instruction after a context switch.
607	 */
608	frstor(&curpcb->pcb_savefpu);
609
610	return (1);
611}
612
613/*
614 * Wrapper for fnsave instruction to handle h/w bugs.  If there is an error
615 * pending, then fnsave generates a bogus IRQ13 on some systems.  Force
616 * any IRQ13 to be handled immediately, and then ignore it.  This routine is
617 * often called at splhigh so it must not use many system services.  In
618 * particular, it's much easier to install a special handler than to
619 * guarantee that it's safe to use npxintr() and its supporting code.
620 */
621void
622npxsave(addr)
623	struct save87 *addr;
624{
625#if defined(APIC_IO)
626	u_int	apic_mask;
627	u_int	old_apic_mask;
628#else
629	u_char	icu1_mask;
630	u_char	icu2_mask;
631	u_char	old_icu1_mask;
632	u_char	old_icu2_mask;
633#endif /* APIC_IO */
634	struct gate_descriptor	save_idt_npxintr;
635
636	disable_intr();
637#if defined(APIC_IO)
638	old_apic_mask = INTRGET();
639#else
640	old_icu1_mask = inb(IO_ICU1 + 1);
641	old_icu2_mask = inb(IO_ICU2 + 1);
642#endif /* APIC_IO */
643	save_idt_npxintr = idt[npx_intrno];
644#if defined(APIC_IO)
645	/** FIXME: try clrIoApicMaskBit( npx0_imask ); */
646	INTRSET( old_apic_mask & ~(npx0_imask & 0xffff) );
647#else
648	outb(IO_ICU1 + 1, old_icu1_mask & ~(IRQ_SLAVE | npx0_imask));
649	outb(IO_ICU2 + 1, old_icu2_mask & ~(npx0_imask >> 8));
650#endif /* APIC_IO */
651	idt[npx_intrno] = npx_idt_probeintr;
652	enable_intr();
653	stop_emulating();
654	fnsave(addr);
655	fnop();
656	start_emulating();
657	npxproc = NULL;
658	disable_intr();
659#if defined(APIC_IO)
660	apic_mask = INTRGET();		/* masks may have changed */
661        INTRSET( (apic_mask & ~(npx0_imask & 0xffff)) |
662		 (old_apic_mask & (npx0_imask & 0xffff)));
663#else
664	icu1_mask = inb(IO_ICU1 + 1);	/* masks may have changed */
665	icu2_mask = inb(IO_ICU2 + 1);
666	outb(IO_ICU1 + 1,
667	     (icu1_mask & ~npx0_imask) | (old_icu1_mask & npx0_imask));
668	outb(IO_ICU2 + 1,
669	     (icu2_mask & ~(npx0_imask >> 8))
670	     | (old_icu2_mask & (npx0_imask >> 8)));
671#endif /* APIC_IO */
672	idt[npx_intrno] = save_idt_npxintr;
673	enable_intr();		/* back to usual state */
674}
675
676#endif /* NNPX > 0 */
677