xref: /freebsd/sys/amd64/amd64/fpu.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
1 /*-
2  * Copyright (c) 1990 William Jolitz.
3  * Copyright (c) 1991 The Regents of the University of California.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 4. Neither the name of the University nor the names of its contributors
15  *    may be used to endorse or promote products derived from this software
16  *    without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  *	from: @(#)npx.c	7.2 (Berkeley) 5/12/91
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/bus.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/mutex.h>
45 #include <sys/proc.h>
46 #include <sys/sysctl.h>
47 #include <machine/bus.h>
48 #include <sys/rman.h>
49 #include <sys/signalvar.h>
50 #include <sys/user.h>
51 
52 #include <machine/cputypes.h>
53 #include <machine/frame.h>
54 #include <machine/intr_machdep.h>
55 #include <machine/md_var.h>
56 #include <machine/pcb.h>
57 #include <machine/psl.h>
58 #include <machine/resource.h>
59 #include <machine/specialreg.h>
60 #include <machine/segments.h>
61 #include <machine/ucontext.h>
62 
63 /*
64  * Floating point support.
65  */
66 
67 #if defined(__GNUC__) && !defined(lint)
68 
69 #define	fldcw(addr)		__asm("fldcw %0" : : "m" (*(addr)))
70 #define	fnclex()		__asm("fnclex")
71 #define	fninit()		__asm("fninit")
72 #define	fnstcw(addr)		__asm __volatile("fnstcw %0" : "=m" (*(addr)))
73 #define	fnstsw(addr)		__asm __volatile("fnstsw %0" : "=m" (*(addr)))
74 #define	fxrstor(addr)		__asm("fxrstor %0" : : "m" (*(addr)))
75 #define	fxsave(addr)		__asm __volatile("fxsave %0" : "=m" (*(addr)))
76 #define	start_emulating()	__asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
77 				      : : "n" (CR0_TS) : "ax")
78 #define	stop_emulating()	__asm("clts")
79 
80 #else	/* not __GNUC__ */
81 
82 void	fldcw(caddr_t addr);
83 void	fnclex(void);
84 void	fninit(void);
85 void	fnstcw(caddr_t addr);
86 void	fnstsw(caddr_t addr);
87 void	fxsave(caddr_t addr);
88 void	fxrstor(caddr_t addr);
89 void	start_emulating(void);
90 void	stop_emulating(void);
91 
92 #endif	/* __GNUC__ */
93 
94 #define GET_FPU_CW(thread) ((thread)->td_pcb->pcb_save.sv_env.en_cw)
95 #define GET_FPU_SW(thread) ((thread)->td_pcb->pcb_save.sv_env.en_sw)
96 
97 typedef u_char bool_t;
98 
99 int	hw_float = 1;
100 SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
101 	CTLFLAG_RD, &hw_float, 0,
102 	"Floatingpoint instructions executed in hardware");
103 
104 static	struct savefpu		fpu_cleanstate;
105 static	bool_t			fpu_cleanstate_ready;
106 
107 /*
108  * Initialize floating point unit.
109  */
110 void
111 fpuinit(void)
112 {
113 	register_t savecrit;
114 	u_short control;
115 
116 	savecrit = intr_disable();
117 	PCPU_SET(fpcurthread, 0);
118 	stop_emulating();
119 	fninit();
120 	control = __INITIAL_FPUCW__;
121 	fldcw(&control);
122 	fxsave(&fpu_cleanstate);
123 	start_emulating();
124 	fpu_cleanstate_ready = 1;
125 	intr_restore(savecrit);
126 }
127 
128 /*
129  * Free coprocessor (if we have it).
130  */
131 void
132 fpuexit(struct thread *td)
133 {
134 	register_t savecrit;
135 
136 	savecrit = intr_disable();
137 	if (curthread == PCPU_GET(fpcurthread)) {
138 		stop_emulating();
139 		fxsave(&PCPU_GET(curpcb)->pcb_save);
140 		start_emulating();
141 		PCPU_SET(fpcurthread, 0);
142 	}
143 	intr_restore(savecrit);
144 }
145 
146 int
147 fpuformat()
148 {
149 
150 	return (_MC_FPFMT_XMM);
151 }
152 
153 /*
154  * The following mechanism is used to ensure that the FPE_... value
155  * that is passed as a trapcode to the signal handler of the user
156  * process does not have more than one bit set.
157  *
158  * Multiple bits may be set if the user process modifies the control
159  * word while a status word bit is already set.  While this is a sign
160  * of bad coding, we have no choise than to narrow them down to one
161  * bit, since we must not send a trapcode that is not exactly one of
162  * the FPE_ macros.
163  *
164  * The mechanism has a static table with 127 entries.  Each combination
165  * of the 7 FPU status word exception bits directly translates to a
166  * position in this table, where a single FPE_... value is stored.
167  * This FPE_... value stored there is considered the "most important"
168  * of the exception bits and will be sent as the signal code.  The
169  * precedence of the bits is based upon Intel Document "Numerical
170  * Applications", Chapter "Special Computational Situations".
171  *
172  * The macro to choose one of these values does these steps: 1) Throw
173  * away status word bits that cannot be masked.  2) Throw away the bits
174  * currently masked in the control word, assuming the user isn't
175  * interested in them anymore.  3) Reinsert status word bit 7 (stack
176  * fault) if it is set, which cannot be masked but must be presered.
177  * 4) Use the remaining bits to point into the trapcode table.
178  *
179  * The 6 maskable bits in order of their preference, as stated in the
180  * above referenced Intel manual:
181  * 1  Invalid operation (FP_X_INV)
182  * 1a   Stack underflow
183  * 1b   Stack overflow
184  * 1c   Operand of unsupported format
185  * 1d   SNaN operand.
186  * 2  QNaN operand (not an exception, irrelavant here)
187  * 3  Any other invalid-operation not mentioned above or zero divide
188  *      (FP_X_INV, FP_X_DZ)
189  * 4  Denormal operand (FP_X_DNML)
190  * 5  Numeric over/underflow (FP_X_OFL, FP_X_UFL)
191  * 6  Inexact result (FP_X_IMP)
192  */
193 static char fpetable[128] = {
194 	0,
195 	FPE_FLTINV,	/*  1 - INV */
196 	FPE_FLTUND,	/*  2 - DNML */
197 	FPE_FLTINV,	/*  3 - INV | DNML */
198 	FPE_FLTDIV,	/*  4 - DZ */
199 	FPE_FLTINV,	/*  5 - INV | DZ */
200 	FPE_FLTDIV,	/*  6 - DNML | DZ */
201 	FPE_FLTINV,	/*  7 - INV | DNML | DZ */
202 	FPE_FLTOVF,	/*  8 - OFL */
203 	FPE_FLTINV,	/*  9 - INV | OFL */
204 	FPE_FLTUND,	/*  A - DNML | OFL */
205 	FPE_FLTINV,	/*  B - INV | DNML | OFL */
206 	FPE_FLTDIV,	/*  C - DZ | OFL */
207 	FPE_FLTINV,	/*  D - INV | DZ | OFL */
208 	FPE_FLTDIV,	/*  E - DNML | DZ | OFL */
209 	FPE_FLTINV,	/*  F - INV | DNML | DZ | OFL */
210 	FPE_FLTUND,	/* 10 - UFL */
211 	FPE_FLTINV,	/* 11 - INV | UFL */
212 	FPE_FLTUND,	/* 12 - DNML | UFL */
213 	FPE_FLTINV,	/* 13 - INV | DNML | UFL */
214 	FPE_FLTDIV,	/* 14 - DZ | UFL */
215 	FPE_FLTINV,	/* 15 - INV | DZ | UFL */
216 	FPE_FLTDIV,	/* 16 - DNML | DZ | UFL */
217 	FPE_FLTINV,	/* 17 - INV | DNML | DZ | UFL */
218 	FPE_FLTOVF,	/* 18 - OFL | UFL */
219 	FPE_FLTINV,	/* 19 - INV | OFL | UFL */
220 	FPE_FLTUND,	/* 1A - DNML | OFL | UFL */
221 	FPE_FLTINV,	/* 1B - INV | DNML | OFL | UFL */
222 	FPE_FLTDIV,	/* 1C - DZ | OFL | UFL */
223 	FPE_FLTINV,	/* 1D - INV | DZ | OFL | UFL */
224 	FPE_FLTDIV,	/* 1E - DNML | DZ | OFL | UFL */
225 	FPE_FLTINV,	/* 1F - INV | DNML | DZ | OFL | UFL */
226 	FPE_FLTRES,	/* 20 - IMP */
227 	FPE_FLTINV,	/* 21 - INV | IMP */
228 	FPE_FLTUND,	/* 22 - DNML | IMP */
229 	FPE_FLTINV,	/* 23 - INV | DNML | IMP */
230 	FPE_FLTDIV,	/* 24 - DZ | IMP */
231 	FPE_FLTINV,	/* 25 - INV | DZ | IMP */
232 	FPE_FLTDIV,	/* 26 - DNML | DZ | IMP */
233 	FPE_FLTINV,	/* 27 - INV | DNML | DZ | IMP */
234 	FPE_FLTOVF,	/* 28 - OFL | IMP */
235 	FPE_FLTINV,	/* 29 - INV | OFL | IMP */
236 	FPE_FLTUND,	/* 2A - DNML | OFL | IMP */
237 	FPE_FLTINV,	/* 2B - INV | DNML | OFL | IMP */
238 	FPE_FLTDIV,	/* 2C - DZ | OFL | IMP */
239 	FPE_FLTINV,	/* 2D - INV | DZ | OFL | IMP */
240 	FPE_FLTDIV,	/* 2E - DNML | DZ | OFL | IMP */
241 	FPE_FLTINV,	/* 2F - INV | DNML | DZ | OFL | IMP */
242 	FPE_FLTUND,	/* 30 - UFL | IMP */
243 	FPE_FLTINV,	/* 31 - INV | UFL | IMP */
244 	FPE_FLTUND,	/* 32 - DNML | UFL | IMP */
245 	FPE_FLTINV,	/* 33 - INV | DNML | UFL | IMP */
246 	FPE_FLTDIV,	/* 34 - DZ | UFL | IMP */
247 	FPE_FLTINV,	/* 35 - INV | DZ | UFL | IMP */
248 	FPE_FLTDIV,	/* 36 - DNML | DZ | UFL | IMP */
249 	FPE_FLTINV,	/* 37 - INV | DNML | DZ | UFL | IMP */
250 	FPE_FLTOVF,	/* 38 - OFL | UFL | IMP */
251 	FPE_FLTINV,	/* 39 - INV | OFL | UFL | IMP */
252 	FPE_FLTUND,	/* 3A - DNML | OFL | UFL | IMP */
253 	FPE_FLTINV,	/* 3B - INV | DNML | OFL | UFL | IMP */
254 	FPE_FLTDIV,	/* 3C - DZ | OFL | UFL | IMP */
255 	FPE_FLTINV,	/* 3D - INV | DZ | OFL | UFL | IMP */
256 	FPE_FLTDIV,	/* 3E - DNML | DZ | OFL | UFL | IMP */
257 	FPE_FLTINV,	/* 3F - INV | DNML | DZ | OFL | UFL | IMP */
258 	FPE_FLTSUB,	/* 40 - STK */
259 	FPE_FLTSUB,	/* 41 - INV | STK */
260 	FPE_FLTUND,	/* 42 - DNML | STK */
261 	FPE_FLTSUB,	/* 43 - INV | DNML | STK */
262 	FPE_FLTDIV,	/* 44 - DZ | STK */
263 	FPE_FLTSUB,	/* 45 - INV | DZ | STK */
264 	FPE_FLTDIV,	/* 46 - DNML | DZ | STK */
265 	FPE_FLTSUB,	/* 47 - INV | DNML | DZ | STK */
266 	FPE_FLTOVF,	/* 48 - OFL | STK */
267 	FPE_FLTSUB,	/* 49 - INV | OFL | STK */
268 	FPE_FLTUND,	/* 4A - DNML | OFL | STK */
269 	FPE_FLTSUB,	/* 4B - INV | DNML | OFL | STK */
270 	FPE_FLTDIV,	/* 4C - DZ | OFL | STK */
271 	FPE_FLTSUB,	/* 4D - INV | DZ | OFL | STK */
272 	FPE_FLTDIV,	/* 4E - DNML | DZ | OFL | STK */
273 	FPE_FLTSUB,	/* 4F - INV | DNML | DZ | OFL | STK */
274 	FPE_FLTUND,	/* 50 - UFL | STK */
275 	FPE_FLTSUB,	/* 51 - INV | UFL | STK */
276 	FPE_FLTUND,	/* 52 - DNML | UFL | STK */
277 	FPE_FLTSUB,	/* 53 - INV | DNML | UFL | STK */
278 	FPE_FLTDIV,	/* 54 - DZ | UFL | STK */
279 	FPE_FLTSUB,	/* 55 - INV | DZ | UFL | STK */
280 	FPE_FLTDIV,	/* 56 - DNML | DZ | UFL | STK */
281 	FPE_FLTSUB,	/* 57 - INV | DNML | DZ | UFL | STK */
282 	FPE_FLTOVF,	/* 58 - OFL | UFL | STK */
283 	FPE_FLTSUB,	/* 59 - INV | OFL | UFL | STK */
284 	FPE_FLTUND,	/* 5A - DNML | OFL | UFL | STK */
285 	FPE_FLTSUB,	/* 5B - INV | DNML | OFL | UFL | STK */
286 	FPE_FLTDIV,	/* 5C - DZ | OFL | UFL | STK */
287 	FPE_FLTSUB,	/* 5D - INV | DZ | OFL | UFL | STK */
288 	FPE_FLTDIV,	/* 5E - DNML | DZ | OFL | UFL | STK */
289 	FPE_FLTSUB,	/* 5F - INV | DNML | DZ | OFL | UFL | STK */
290 	FPE_FLTRES,	/* 60 - IMP | STK */
291 	FPE_FLTSUB,	/* 61 - INV | IMP | STK */
292 	FPE_FLTUND,	/* 62 - DNML | IMP | STK */
293 	FPE_FLTSUB,	/* 63 - INV | DNML | IMP | STK */
294 	FPE_FLTDIV,	/* 64 - DZ | IMP | STK */
295 	FPE_FLTSUB,	/* 65 - INV | DZ | IMP | STK */
296 	FPE_FLTDIV,	/* 66 - DNML | DZ | IMP | STK */
297 	FPE_FLTSUB,	/* 67 - INV | DNML | DZ | IMP | STK */
298 	FPE_FLTOVF,	/* 68 - OFL | IMP | STK */
299 	FPE_FLTSUB,	/* 69 - INV | OFL | IMP | STK */
300 	FPE_FLTUND,	/* 6A - DNML | OFL | IMP | STK */
301 	FPE_FLTSUB,	/* 6B - INV | DNML | OFL | IMP | STK */
302 	FPE_FLTDIV,	/* 6C - DZ | OFL | IMP | STK */
303 	FPE_FLTSUB,	/* 6D - INV | DZ | OFL | IMP | STK */
304 	FPE_FLTDIV,	/* 6E - DNML | DZ | OFL | IMP | STK */
305 	FPE_FLTSUB,	/* 6F - INV | DNML | DZ | OFL | IMP | STK */
306 	FPE_FLTUND,	/* 70 - UFL | IMP | STK */
307 	FPE_FLTSUB,	/* 71 - INV | UFL | IMP | STK */
308 	FPE_FLTUND,	/* 72 - DNML | UFL | IMP | STK */
309 	FPE_FLTSUB,	/* 73 - INV | DNML | UFL | IMP | STK */
310 	FPE_FLTDIV,	/* 74 - DZ | UFL | IMP | STK */
311 	FPE_FLTSUB,	/* 75 - INV | DZ | UFL | IMP | STK */
312 	FPE_FLTDIV,	/* 76 - DNML | DZ | UFL | IMP | STK */
313 	FPE_FLTSUB,	/* 77 - INV | DNML | DZ | UFL | IMP | STK */
314 	FPE_FLTOVF,	/* 78 - OFL | UFL | IMP | STK */
315 	FPE_FLTSUB,	/* 79 - INV | OFL | UFL | IMP | STK */
316 	FPE_FLTUND,	/* 7A - DNML | OFL | UFL | IMP | STK */
317 	FPE_FLTSUB,	/* 7B - INV | DNML | OFL | UFL | IMP | STK */
318 	FPE_FLTDIV,	/* 7C - DZ | OFL | UFL | IMP | STK */
319 	FPE_FLTSUB,	/* 7D - INV | DZ | OFL | UFL | IMP | STK */
320 	FPE_FLTDIV,	/* 7E - DNML | DZ | OFL | UFL | IMP | STK */
321 	FPE_FLTSUB,	/* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */
322 };
323 
324 /*
325  * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
326  *
327  * Clearing exceptions is necessary mainly to avoid IRQ13 bugs.  We now
328  * depend on longjmp() restoring a usable state.  Restoring the state
329  * or examining it might fail if we didn't clear exceptions.
330  *
331  * The error code chosen will be one of the FPE_... macros. It will be
332  * sent as the second argument to old BSD-style signal handlers and as
333  * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers.
334  *
335  * XXX the FP state is not preserved across signal handlers.  So signal
336  * handlers cannot afford to do FP unless they preserve the state or
337  * longjmp() out.  Both preserving the state and longjmp()ing may be
338  * destroyed by IRQ13 bugs.  Clearing FP exceptions is not an acceptable
339  * solution for signals other than SIGFPE.
340  */
341 int
342 fputrap()
343 {
344 	register_t savecrit;
345 	u_short control, status;
346 
347 	savecrit = intr_disable();
348 
349 	/*
350 	 * Interrupt handling (for another interrupt) may have pushed the
351 	 * state to memory.  Fetch the relevant parts of the state from
352 	 * wherever they are.
353 	 */
354 	if (PCPU_GET(fpcurthread) != curthread) {
355 		control = GET_FPU_CW(curthread);
356 		status = GET_FPU_SW(curthread);
357 	} else {
358 		fnstcw(&control);
359 		fnstsw(&status);
360 	}
361 
362 	if (PCPU_GET(fpcurthread) == curthread)
363 		fnclex();
364 	intr_restore(savecrit);
365 	return (fpetable[status & ((~control & 0x3f) | 0x40)]);
366 }
367 
368 /*
369  * Implement device not available (DNA) exception
370  *
371  * It would be better to switch FP context here (if curthread != fpcurthread)
372  * and not necessarily for every context switch, but it is too hard to
373  * access foreign pcb's.
374  */
375 
376 static int err_count = 0;
377 
378 int
379 fpudna()
380 {
381 	struct pcb *pcb;
382 	register_t s;
383 	u_short control;
384 
385 	if (PCPU_GET(fpcurthread) == curthread) {
386 		printf("fpudna: fpcurthread == curthread %d times\n",
387 		    ++err_count);
388 		stop_emulating();
389 		return (1);
390 	}
391 	if (PCPU_GET(fpcurthread) != NULL) {
392 		printf("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
393 		       PCPU_GET(fpcurthread),
394 		       PCPU_GET(fpcurthread)->td_proc->p_pid,
395 		       curthread, curthread->td_proc->p_pid);
396 		panic("fpudna");
397 	}
398 	s = intr_disable();
399 	stop_emulating();
400 	/*
401 	 * Record new context early in case frstor causes a trap.
402 	 */
403 	PCPU_SET(fpcurthread, curthread);
404 	pcb = PCPU_GET(curpcb);
405 
406 	if ((pcb->pcb_flags & PCB_FPUINITDONE) == 0) {
407 		/*
408 		 * This is the first time this thread has used the FPU or
409 		 * the PCB doesn't contain a clean FPU state.  Explicitly
410 		 * initialize the FPU and load the default control word.
411 		 */
412 		fninit();
413 		control = __INITIAL_FPUCW__;
414 		fldcw(&control);
415 		pcb->pcb_flags |= PCB_FPUINITDONE;
416 	} else
417 		fxrstor(&pcb->pcb_save);
418 	intr_restore(s);
419 
420 	return (1);
421 }
422 
423 /*
424  * This should be called with interrupts disabled and only when the owning
425  * FPU thread is non-null.
426  */
427 void
428 fpudrop()
429 {
430 	struct thread *td;
431 
432 	td = PCPU_GET(fpcurthread);
433 	PCPU_SET(fpcurthread, NULL);
434 	td->td_pcb->pcb_flags &= ~PCB_FPUINITDONE;
435 	start_emulating();
436 }
437 
438 /*
439  * Get the state of the FPU without dropping ownership (if possible).
440  * It returns the FPU ownership status.
441  */
442 int
443 fpugetregs(struct thread *td, struct savefpu *addr)
444 {
445 	register_t s;
446 
447 	if ((td->td_pcb->pcb_flags & PCB_FPUINITDONE) == 0) {
448 		if (fpu_cleanstate_ready)
449 			bcopy(&fpu_cleanstate, addr, sizeof(fpu_cleanstate));
450 		else
451 			bzero(addr, sizeof(*addr));
452 		return (_MC_FPOWNED_NONE);
453 	}
454 	s = intr_disable();
455 	if (td == PCPU_GET(fpcurthread)) {
456 		fxsave(addr);
457 		intr_restore(s);
458 		return (_MC_FPOWNED_FPU);
459 	} else {
460 		intr_restore(s);
461 		bcopy(&td->td_pcb->pcb_save, addr, sizeof(*addr));
462 		return (_MC_FPOWNED_PCB);
463 	}
464 }
465 
466 /*
467  * Set the state of the FPU.
468  */
469 void
470 fpusetregs(struct thread *td, struct savefpu *addr)
471 {
472 	register_t s;
473 
474 	s = intr_disable();
475 	if (td == PCPU_GET(fpcurthread)) {
476 		fxrstor(addr);
477 		intr_restore(s);
478 	} else {
479 		intr_restore(s);
480 		bcopy(addr, &td->td_pcb->pcb_save, sizeof(*addr));
481 	}
482 	curthread->td_pcb->pcb_flags |= PCB_FPUINITDONE;
483 }
484 
485 /*
486  * This really sucks.  We want the acpi version only, but it requires
487  * the isa_if.h file in order to get the definitions.
488  */
489 #include "opt_isa.h"
490 #ifdef DEV_ISA
491 #include <isa/isavar.h>
492 /*
493  * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI.
494  */
495 static struct isa_pnp_id fpupnp_ids[] = {
496 	{ 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
497 	{ 0 }
498 };
499 
500 static int
501 fpupnp_probe(device_t dev)
502 {
503 	int result;
504 
505 	result = ISA_PNP_PROBE(device_get_parent(dev), dev, fpupnp_ids);
506 	if (result <= 0)
507 		device_quiet(dev);
508 	return (result);
509 }
510 
511 static int
512 fpupnp_attach(device_t dev)
513 {
514 
515 	return (0);
516 }
517 
518 static device_method_t fpupnp_methods[] = {
519 	/* Device interface */
520 	DEVMETHOD(device_probe,		fpupnp_probe),
521 	DEVMETHOD(device_attach,	fpupnp_attach),
522 	DEVMETHOD(device_detach,	bus_generic_detach),
523 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
524 	DEVMETHOD(device_suspend,	bus_generic_suspend),
525 	DEVMETHOD(device_resume,	bus_generic_resume),
526 
527 	{ 0, 0 }
528 };
529 
530 static driver_t fpupnp_driver = {
531 	"fpupnp",
532 	fpupnp_methods,
533 	1,			/* no softc */
534 };
535 
536 static devclass_t fpupnp_devclass;
537 
538 DRIVER_MODULE(fpupnp, acpi, fpupnp_driver, fpupnp_devclass, 0, 0);
539 #endif	/* DEV_ISA */
540