fpu.c revision 122849
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 *	@(#)npx.c	7.2 (Berkeley) 5/12/91
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/sys/amd64/amd64/fpu.c 122849 2003-11-17 08:58:16Z peter $");
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/bus.h>
43#include <sys/kernel.h>
44#include <sys/lock.h>
45#include <sys/malloc.h>
46#include <sys/module.h>
47#include <sys/mutex.h>
48#include <sys/mutex.h>
49#include <sys/proc.h>
50#include <sys/sysctl.h>
51#include <machine/bus.h>
52#include <sys/rman.h>
53#include <sys/signalvar.h>
54#include <sys/user.h>
55
56#include <machine/cputypes.h>
57#include <machine/frame.h>
58#include <machine/intr_machdep.h>
59#include <machine/md_var.h>
60#include <machine/pcb.h>
61#include <machine/psl.h>
62#include <machine/resource.h>
63#include <machine/specialreg.h>
64#include <machine/segments.h>
65#include <machine/ucontext.h>
66
67/*
68 * Floating point support.
69 */
70
71#if defined(__GNUC__) && !defined(lint)
72
73#define	fldcw(addr)		__asm("fldcw %0" : : "m" (*(addr)))
74#define	fnclex()		__asm("fnclex")
75#define	fninit()		__asm("fninit")
76#define	fnstcw(addr)		__asm __volatile("fnstcw %0" : "=m" (*(addr)))
77#define	fnstsw(addr)		__asm __volatile("fnstsw %0" : "=m" (*(addr)))
78#define	fxrstor(addr)		__asm("fxrstor %0" : : "m" (*(addr)))
79#define	fxsave(addr)		__asm __volatile("fxsave %0" : "=m" (*(addr)))
80#define	start_emulating()	__asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
81				      : : "n" (CR0_TS) : "ax")
82#define	stop_emulating()	__asm("clts")
83
84#else	/* not __GNUC__ */
85
86void	fldcw(caddr_t addr);
87void	fnclex(void);
88void	fninit(void);
89void	fnstcw(caddr_t addr);
90void	fnstsw(caddr_t addr);
91void	fxsave(caddr_t addr);
92void	fxrstor(caddr_t addr);
93void	start_emulating(void);
94void	stop_emulating(void);
95
96#endif	/* __GNUC__ */
97
98#define GET_FPU_CW(thread) ((thread)->td_pcb->pcb_save.sv_env.en_cw)
99#define GET_FPU_SW(thread) ((thread)->td_pcb->pcb_save.sv_env.en_sw)
100
101typedef u_char bool_t;
102
103int	hw_float = 1;
104SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
105	CTLFLAG_RD, &hw_float, 0,
106	"Floatingpoint instructions executed in hardware");
107
108static	struct savefpu		fpu_cleanstate;
109static	bool_t			fpu_cleanstate_ready;
110
111/*
112 * Initialize floating point unit.
113 */
114void
115fpuinit()
116{
117	register_t savecrit;
118	u_short control;
119
120	/*
121	 * fpusave() initializes the fpu and sets fpcurthread = NULL
122	 */
123	savecrit = intr_disable();
124	fpusave(&fpu_cleanstate);	/* XXX borrow for now */
125	stop_emulating();
126	/* XXX fpusave() doesn't actually initialize the fpu in the SSE case. */
127	fninit();
128	control = __INITIAL_FPUCW__;
129	fldcw(&control);
130	start_emulating();
131	intr_restore(savecrit);
132
133	savecrit = intr_disable();
134	stop_emulating();
135	fxsave(&fpu_cleanstate);
136	start_emulating();
137	fpu_cleanstate_ready = 1;
138	intr_restore(savecrit);
139}
140
141/*
142 * Free coprocessor (if we have it).
143 */
144void
145fpuexit(struct thread *td)
146{
147	register_t savecrit;
148
149	savecrit = intr_disable();
150	if (curthread == PCPU_GET(fpcurthread))
151		fpusave(&PCPU_GET(curpcb)->pcb_save);
152	intr_restore(savecrit);
153}
154
155int
156fpuformat()
157{
158
159	return (_MC_FPFMT_XMM);
160}
161
162/*
163 * The following mechanism is used to ensure that the FPE_... value
164 * that is passed as a trapcode to the signal handler of the user
165 * process does not have more than one bit set.
166 *
167 * Multiple bits may be set if the user process modifies the control
168 * word while a status word bit is already set.  While this is a sign
169 * of bad coding, we have no choise than to narrow them down to one
170 * bit, since we must not send a trapcode that is not exactly one of
171 * the FPE_ macros.
172 *
173 * The mechanism has a static table with 127 entries.  Each combination
174 * of the 7 FPU status word exception bits directly translates to a
175 * position in this table, where a single FPE_... value is stored.
176 * This FPE_... value stored there is considered the "most important"
177 * of the exception bits and will be sent as the signal code.  The
178 * precedence of the bits is based upon Intel Document "Numerical
179 * Applications", Chapter "Special Computational Situations".
180 *
181 * The macro to choose one of these values does these steps: 1) Throw
182 * away status word bits that cannot be masked.  2) Throw away the bits
183 * currently masked in the control word, assuming the user isn't
184 * interested in them anymore.  3) Reinsert status word bit 7 (stack
185 * fault) if it is set, which cannot be masked but must be presered.
186 * 4) Use the remaining bits to point into the trapcode table.
187 *
188 * The 6 maskable bits in order of their preference, as stated in the
189 * above referenced Intel manual:
190 * 1  Invalid operation (FP_X_INV)
191 * 1a   Stack underflow
192 * 1b   Stack overflow
193 * 1c   Operand of unsupported format
194 * 1d   SNaN operand.
195 * 2  QNaN operand (not an exception, irrelavant here)
196 * 3  Any other invalid-operation not mentioned above or zero divide
197 *      (FP_X_INV, FP_X_DZ)
198 * 4  Denormal operand (FP_X_DNML)
199 * 5  Numeric over/underflow (FP_X_OFL, FP_X_UFL)
200 * 6  Inexact result (FP_X_IMP)
201 */
202static char fpetable[128] = {
203	0,
204	FPE_FLTINV,	/*  1 - INV */
205	FPE_FLTUND,	/*  2 - DNML */
206	FPE_FLTINV,	/*  3 - INV | DNML */
207	FPE_FLTDIV,	/*  4 - DZ */
208	FPE_FLTINV,	/*  5 - INV | DZ */
209	FPE_FLTDIV,	/*  6 - DNML | DZ */
210	FPE_FLTINV,	/*  7 - INV | DNML | DZ */
211	FPE_FLTOVF,	/*  8 - OFL */
212	FPE_FLTINV,	/*  9 - INV | OFL */
213	FPE_FLTUND,	/*  A - DNML | OFL */
214	FPE_FLTINV,	/*  B - INV | DNML | OFL */
215	FPE_FLTDIV,	/*  C - DZ | OFL */
216	FPE_FLTINV,	/*  D - INV | DZ | OFL */
217	FPE_FLTDIV,	/*  E - DNML | DZ | OFL */
218	FPE_FLTINV,	/*  F - INV | DNML | DZ | OFL */
219	FPE_FLTUND,	/* 10 - UFL */
220	FPE_FLTINV,	/* 11 - INV | UFL */
221	FPE_FLTUND,	/* 12 - DNML | UFL */
222	FPE_FLTINV,	/* 13 - INV | DNML | UFL */
223	FPE_FLTDIV,	/* 14 - DZ | UFL */
224	FPE_FLTINV,	/* 15 - INV | DZ | UFL */
225	FPE_FLTDIV,	/* 16 - DNML | DZ | UFL */
226	FPE_FLTINV,	/* 17 - INV | DNML | DZ | UFL */
227	FPE_FLTOVF,	/* 18 - OFL | UFL */
228	FPE_FLTINV,	/* 19 - INV | OFL | UFL */
229	FPE_FLTUND,	/* 1A - DNML | OFL | UFL */
230	FPE_FLTINV,	/* 1B - INV | DNML | OFL | UFL */
231	FPE_FLTDIV,	/* 1C - DZ | OFL | UFL */
232	FPE_FLTINV,	/* 1D - INV | DZ | OFL | UFL */
233	FPE_FLTDIV,	/* 1E - DNML | DZ | OFL | UFL */
234	FPE_FLTINV,	/* 1F - INV | DNML | DZ | OFL | UFL */
235	FPE_FLTRES,	/* 20 - IMP */
236	FPE_FLTINV,	/* 21 - INV | IMP */
237	FPE_FLTUND,	/* 22 - DNML | IMP */
238	FPE_FLTINV,	/* 23 - INV | DNML | IMP */
239	FPE_FLTDIV,	/* 24 - DZ | IMP */
240	FPE_FLTINV,	/* 25 - INV | DZ | IMP */
241	FPE_FLTDIV,	/* 26 - DNML | DZ | IMP */
242	FPE_FLTINV,	/* 27 - INV | DNML | DZ | IMP */
243	FPE_FLTOVF,	/* 28 - OFL | IMP */
244	FPE_FLTINV,	/* 29 - INV | OFL | IMP */
245	FPE_FLTUND,	/* 2A - DNML | OFL | IMP */
246	FPE_FLTINV,	/* 2B - INV | DNML | OFL | IMP */
247	FPE_FLTDIV,	/* 2C - DZ | OFL | IMP */
248	FPE_FLTINV,	/* 2D - INV | DZ | OFL | IMP */
249	FPE_FLTDIV,	/* 2E - DNML | DZ | OFL | IMP */
250	FPE_FLTINV,	/* 2F - INV | DNML | DZ | OFL | IMP */
251	FPE_FLTUND,	/* 30 - UFL | IMP */
252	FPE_FLTINV,	/* 31 - INV | UFL | IMP */
253	FPE_FLTUND,	/* 32 - DNML | UFL | IMP */
254	FPE_FLTINV,	/* 33 - INV | DNML | UFL | IMP */
255	FPE_FLTDIV,	/* 34 - DZ | UFL | IMP */
256	FPE_FLTINV,	/* 35 - INV | DZ | UFL | IMP */
257	FPE_FLTDIV,	/* 36 - DNML | DZ | UFL | IMP */
258	FPE_FLTINV,	/* 37 - INV | DNML | DZ | UFL | IMP */
259	FPE_FLTOVF,	/* 38 - OFL | UFL | IMP */
260	FPE_FLTINV,	/* 39 - INV | OFL | UFL | IMP */
261	FPE_FLTUND,	/* 3A - DNML | OFL | UFL | IMP */
262	FPE_FLTINV,	/* 3B - INV | DNML | OFL | UFL | IMP */
263	FPE_FLTDIV,	/* 3C - DZ | OFL | UFL | IMP */
264	FPE_FLTINV,	/* 3D - INV | DZ | OFL | UFL | IMP */
265	FPE_FLTDIV,	/* 3E - DNML | DZ | OFL | UFL | IMP */
266	FPE_FLTINV,	/* 3F - INV | DNML | DZ | OFL | UFL | IMP */
267	FPE_FLTSUB,	/* 40 - STK */
268	FPE_FLTSUB,	/* 41 - INV | STK */
269	FPE_FLTUND,	/* 42 - DNML | STK */
270	FPE_FLTSUB,	/* 43 - INV | DNML | STK */
271	FPE_FLTDIV,	/* 44 - DZ | STK */
272	FPE_FLTSUB,	/* 45 - INV | DZ | STK */
273	FPE_FLTDIV,	/* 46 - DNML | DZ | STK */
274	FPE_FLTSUB,	/* 47 - INV | DNML | DZ | STK */
275	FPE_FLTOVF,	/* 48 - OFL | STK */
276	FPE_FLTSUB,	/* 49 - INV | OFL | STK */
277	FPE_FLTUND,	/* 4A - DNML | OFL | STK */
278	FPE_FLTSUB,	/* 4B - INV | DNML | OFL | STK */
279	FPE_FLTDIV,	/* 4C - DZ | OFL | STK */
280	FPE_FLTSUB,	/* 4D - INV | DZ | OFL | STK */
281	FPE_FLTDIV,	/* 4E - DNML | DZ | OFL | STK */
282	FPE_FLTSUB,	/* 4F - INV | DNML | DZ | OFL | STK */
283	FPE_FLTUND,	/* 50 - UFL | STK */
284	FPE_FLTSUB,	/* 51 - INV | UFL | STK */
285	FPE_FLTUND,	/* 52 - DNML | UFL | STK */
286	FPE_FLTSUB,	/* 53 - INV | DNML | UFL | STK */
287	FPE_FLTDIV,	/* 54 - DZ | UFL | STK */
288	FPE_FLTSUB,	/* 55 - INV | DZ | UFL | STK */
289	FPE_FLTDIV,	/* 56 - DNML | DZ | UFL | STK */
290	FPE_FLTSUB,	/* 57 - INV | DNML | DZ | UFL | STK */
291	FPE_FLTOVF,	/* 58 - OFL | UFL | STK */
292	FPE_FLTSUB,	/* 59 - INV | OFL | UFL | STK */
293	FPE_FLTUND,	/* 5A - DNML | OFL | UFL | STK */
294	FPE_FLTSUB,	/* 5B - INV | DNML | OFL | UFL | STK */
295	FPE_FLTDIV,	/* 5C - DZ | OFL | UFL | STK */
296	FPE_FLTSUB,	/* 5D - INV | DZ | OFL | UFL | STK */
297	FPE_FLTDIV,	/* 5E - DNML | DZ | OFL | UFL | STK */
298	FPE_FLTSUB,	/* 5F - INV | DNML | DZ | OFL | UFL | STK */
299	FPE_FLTRES,	/* 60 - IMP | STK */
300	FPE_FLTSUB,	/* 61 - INV | IMP | STK */
301	FPE_FLTUND,	/* 62 - DNML | IMP | STK */
302	FPE_FLTSUB,	/* 63 - INV | DNML | IMP | STK */
303	FPE_FLTDIV,	/* 64 - DZ | IMP | STK */
304	FPE_FLTSUB,	/* 65 - INV | DZ | IMP | STK */
305	FPE_FLTDIV,	/* 66 - DNML | DZ | IMP | STK */
306	FPE_FLTSUB,	/* 67 - INV | DNML | DZ | IMP | STK */
307	FPE_FLTOVF,	/* 68 - OFL | IMP | STK */
308	FPE_FLTSUB,	/* 69 - INV | OFL | IMP | STK */
309	FPE_FLTUND,	/* 6A - DNML | OFL | IMP | STK */
310	FPE_FLTSUB,	/* 6B - INV | DNML | OFL | IMP | STK */
311	FPE_FLTDIV,	/* 6C - DZ | OFL | IMP | STK */
312	FPE_FLTSUB,	/* 6D - INV | DZ | OFL | IMP | STK */
313	FPE_FLTDIV,	/* 6E - DNML | DZ | OFL | IMP | STK */
314	FPE_FLTSUB,	/* 6F - INV | DNML | DZ | OFL | IMP | STK */
315	FPE_FLTUND,	/* 70 - UFL | IMP | STK */
316	FPE_FLTSUB,	/* 71 - INV | UFL | IMP | STK */
317	FPE_FLTUND,	/* 72 - DNML | UFL | IMP | STK */
318	FPE_FLTSUB,	/* 73 - INV | DNML | UFL | IMP | STK */
319	FPE_FLTDIV,	/* 74 - DZ | UFL | IMP | STK */
320	FPE_FLTSUB,	/* 75 - INV | DZ | UFL | IMP | STK */
321	FPE_FLTDIV,	/* 76 - DNML | DZ | UFL | IMP | STK */
322	FPE_FLTSUB,	/* 77 - INV | DNML | DZ | UFL | IMP | STK */
323	FPE_FLTOVF,	/* 78 - OFL | UFL | IMP | STK */
324	FPE_FLTSUB,	/* 79 - INV | OFL | UFL | IMP | STK */
325	FPE_FLTUND,	/* 7A - DNML | OFL | UFL | IMP | STK */
326	FPE_FLTSUB,	/* 7B - INV | DNML | OFL | UFL | IMP | STK */
327	FPE_FLTDIV,	/* 7C - DZ | OFL | UFL | IMP | STK */
328	FPE_FLTSUB,	/* 7D - INV | DZ | OFL | UFL | IMP | STK */
329	FPE_FLTDIV,	/* 7E - DNML | DZ | OFL | UFL | IMP | STK */
330	FPE_FLTSUB,	/* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */
331};
332
333/*
334 * Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
335 *
336 * Clearing exceptions is necessary mainly to avoid IRQ13 bugs.  We now
337 * depend on longjmp() restoring a usable state.  Restoring the state
338 * or examining it might fail if we didn't clear exceptions.
339 *
340 * The error code chosen will be one of the FPE_... macros. It will be
341 * sent as the second argument to old BSD-style signal handlers and as
342 * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers.
343 *
344 * XXX the FP state is not preserved across signal handlers.  So signal
345 * handlers cannot afford to do FP unless they preserve the state or
346 * longjmp() out.  Both preserving the state and longjmp()ing may be
347 * destroyed by IRQ13 bugs.  Clearing FP exceptions is not an acceptable
348 * solution for signals other than SIGFPE.
349 */
350int
351fputrap()
352{
353	register_t savecrit;
354	u_short control, status;
355
356	savecrit = intr_disable();
357
358	/*
359	 * Interrupt handling (for another interrupt) may have pushed the
360	 * state to memory.  Fetch the relevant parts of the state from
361	 * wherever they are.
362	 */
363	if (PCPU_GET(fpcurthread) != curthread) {
364		control = GET_FPU_CW(curthread);
365		status = GET_FPU_SW(curthread);
366	} else {
367		fnstcw(&control);
368		fnstsw(&status);
369	}
370
371	if (PCPU_GET(fpcurthread) == curthread)
372		fnclex();
373	intr_restore(savecrit);
374	return (fpetable[status & ((~control & 0x3f) | 0x40)]);
375}
376
377/*
378 * Implement device not available (DNA) exception
379 *
380 * It would be better to switch FP context here (if curthread != fpcurthread)
381 * and not necessarily for every context switch, but it is too hard to
382 * access foreign pcb's.
383 */
384
385static int err_count = 0;
386
387int
388fpudna()
389{
390	struct pcb *pcb;
391	register_t s;
392	u_short control;
393
394	if (PCPU_GET(fpcurthread) == curthread) {
395		printf("fpudna: fpcurthread == curthread %d times\n",
396		    ++err_count);
397		stop_emulating();
398		return (1);
399	}
400	if (PCPU_GET(fpcurthread) != NULL) {
401		printf("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
402		       PCPU_GET(fpcurthread),
403		       PCPU_GET(fpcurthread)->td_proc->p_pid,
404		       curthread, curthread->td_proc->p_pid);
405		panic("fpudna");
406	}
407	s = intr_disable();
408	stop_emulating();
409	/*
410	 * Record new context early in case frstor causes a trap.
411	 */
412	PCPU_SET(fpcurthread, curthread);
413	pcb = PCPU_GET(curpcb);
414
415	if ((pcb->pcb_flags & PCB_FPUINITDONE) == 0) {
416		/*
417		 * This is the first time this thread has used the FPU or
418		 * the PCB doesn't contain a clean FPU state.  Explicitly
419		 * initialize the FPU and load the default control word.
420		 */
421		fninit();
422		control = __INITIAL_FPUCW__;
423		fldcw(&control);
424		pcb->pcb_flags |= PCB_FPUINITDONE;
425	} else {
426		/*
427		 * The following frstor may cause a trap when the state
428		 * being restored has a pending error.  The error will
429		 * appear to have been triggered by the current (fpu) user
430		 * instruction even when that instruction is a no-wait
431		 * instruction that should not trigger an error (e.g.,
432		 * instructions are broken the same as frstor, so our
433		 * treatment does not amplify the breakage.
434		 */
435		fxrstor(&pcb->pcb_save);
436	}
437	intr_restore(s);
438
439	return (1);
440}
441
442/*
443 * Wrapper for fnsave instruction.
444 *
445 * fpusave() must be called with interrupts disabled, so that it clears
446 * fpcurthread atomically with saving the state.  We require callers to do the
447 * disabling, since most callers need to disable interrupts anyway to call
448 * fpusave() atomically with checking fpcurthread.
449 */
450void
451fpusave(struct savefpu *addr)
452{
453
454	stop_emulating();
455	fxsave(addr);
456	start_emulating();
457	PCPU_SET(fpcurthread, NULL);
458}
459
460/*
461 * This should be called with interrupts disabled and only when the owning
462 * FPU thread is non-null.
463 */
464void
465fpudrop()
466{
467	struct thread *td;
468
469	td = PCPU_GET(fpcurthread);
470	PCPU_SET(fpcurthread, NULL);
471	td->td_pcb->pcb_flags &= ~PCB_FPUINITDONE;
472	start_emulating();
473}
474
475/*
476 * Get the state of the FPU without dropping ownership (if possible).
477 * It returns the FPU ownership status.
478 */
479int
480fpugetregs(struct thread *td, struct savefpu *addr)
481{
482	register_t s;
483
484	if ((td->td_pcb->pcb_flags & PCB_FPUINITDONE) == 0) {
485		if (fpu_cleanstate_ready)
486			bcopy(&fpu_cleanstate, addr, sizeof(fpu_cleanstate));
487		else
488			bzero(addr, sizeof(*addr));
489		return (_MC_FPOWNED_NONE);
490	}
491	s = intr_disable();
492	if (td == PCPU_GET(fpcurthread)) {
493		fxsave(addr);
494		intr_restore(s);
495		return (_MC_FPOWNED_FPU);
496	} else {
497		intr_restore(s);
498		bcopy(&td->td_pcb->pcb_save, addr, sizeof(*addr));
499		return (_MC_FPOWNED_PCB);
500	}
501}
502
503/*
504 * Set the state of the FPU.
505 */
506void
507fpusetregs(struct thread *td, struct savefpu *addr)
508{
509	register_t s;
510
511	s = intr_disable();
512	if (td == PCPU_GET(fpcurthread)) {
513		fxrstor(addr);
514		intr_restore(s);
515	} else {
516		intr_restore(s);
517		bcopy(addr, &td->td_pcb->pcb_save, sizeof(*addr));
518	}
519	curthread->td_pcb->pcb_flags |= PCB_FPUINITDONE;
520}
521
522/*
523 * This really sucks.  We want the acpi version only, but it requires
524 * the isa_if.h file in order to get the definitions.
525 */
526#include "opt_isa.h"
527#ifdef DEV_ISA
528#include <isa/isavar.h>
529/*
530 * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI.
531 */
532static struct isa_pnp_id fpupnp_ids[] = {
533	{ 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
534	{ 0 }
535};
536
537static int
538fpupnp_probe(device_t dev)
539{
540	int result;
541
542	result = ISA_PNP_PROBE(device_get_parent(dev), dev, fpupnp_ids);
543	if (result <= 0)
544		device_quiet(dev);
545	return (result);
546}
547
548static int
549fpupnp_attach(device_t dev)
550{
551
552	return (0);
553}
554
555static device_method_t fpupnp_methods[] = {
556	/* Device interface */
557	DEVMETHOD(device_probe,		fpupnp_probe),
558	DEVMETHOD(device_attach,	fpupnp_attach),
559	DEVMETHOD(device_detach,	bus_generic_detach),
560	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
561	DEVMETHOD(device_suspend,	bus_generic_suspend),
562	DEVMETHOD(device_resume,	bus_generic_resume),
563
564	{ 0, 0 }
565};
566
567static driver_t fpupnp_driver = {
568	"fpupnp",
569	fpupnp_methods,
570	1,			/* no softc */
571};
572
573static devclass_t fpupnp_devclass;
574
575DRIVER_MODULE(fpupnp, acpi, fpupnp_driver, fpupnp_devclass, 0, 0);
576#endif	/* DEV_ISA */
577