2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990 William Jolitz.
5 * Copyright (c) 1991 The Regents of the University of California.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * from: @(#)npx.c 7.2 (Berkeley) 5/12/91
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include <sys/param.h>
39 #include <sys/systm.h>
41 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/mutex.h>
46 #include <sys/mutex.h>
48 #include <sys/sysctl.h>
49 #include <machine/bus.h>
51 #include <sys/signalvar.h>
54 #include <machine/cputypes.h>
55 #include <machine/frame.h>
56 #include <machine/intr_machdep.h>
57 #include <machine/md_var.h>
58 #include <machine/pcb.h>
59 #include <machine/psl.h>
60 #include <machine/resource.h>
61 #include <machine/specialreg.h>
62 #include <machine/segments.h>
63 #include <machine/ucontext.h>
64 #include <x86/ifunc.h>
67 * Floating point support.
70 #if defined(__GNUCLIKE_ASM) && !defined(lint)
72 #define fldcw(cw) __asm __volatile("fldcw %0" : : "m" (cw))
73 #define fnclex() __asm __volatile("fnclex")
74 #define fninit() __asm __volatile("fninit")
75 #define fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
76 #define fnstsw(addr) __asm __volatile("fnstsw %0" : "=am" (*(addr)))
77 #define fxrstor(addr) __asm __volatile("fxrstor %0" : : "m" (*(addr)))
78 #define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr)))
79 #define ldmxcsr(csr) __asm __volatile("ldmxcsr %0" : : "m" (csr))
80 #define stmxcsr(addr) __asm __volatile("stmxcsr %0" : : "m" (*(addr)))
83 xrstor(char *addr, uint64_t mask)
89 __asm __volatile("xrstor %0" : : "m" (*addr), "a" (low), "d" (hi));
93 xsave(char *addr, uint64_t mask)
99 __asm __volatile("xsave %0" : "=m" (*addr) : "a" (low), "d" (hi) :
104 xsaveopt(char *addr, uint64_t mask)
110 __asm __volatile("xsaveopt %0" : "=m" (*addr) : "a" (low), "d" (hi) :
114 #else /* !(__GNUCLIKE_ASM && !lint) */
116 void fldcw(u_short cw);
119 void fnstcw(caddr_t addr);
120 void fnstsw(caddr_t addr);
121 void fxsave(caddr_t addr);
122 void fxrstor(caddr_t addr);
123 void ldmxcsr(u_int csr);
124 void stmxcsr(u_int *csr);
125 void xrstor(char *addr, uint64_t mask);
126 void xsave(char *addr, uint64_t mask);
127 void xsaveopt(char *addr, uint64_t mask);
129 #endif /* __GNUCLIKE_ASM && !lint */
131 #define start_emulating() load_cr0(rcr0() | CR0_TS)
132 #define stop_emulating() clts()
134 CTASSERT(sizeof(struct savefpu) == 512);
135 CTASSERT(sizeof(struct xstate_hdr) == 64);
136 CTASSERT(sizeof(struct savefpu_ymm) == 832);
139 * This requirement is to make it easier for asm code to calculate
140 * offset of the fpu save area from the pcb address. FPU save area
141 * must be 64-byte aligned.
143 CTASSERT(sizeof(struct pcb) % XSAVE_AREA_ALIGN == 0);
146 * Ensure the copy of XCR0 saved in a core is contained in the padding
149 CTASSERT(X86_XSTATE_XCR0_OFFSET >= offsetof(struct savefpu, sv_pad) &&
150 X86_XSTATE_XCR0_OFFSET + sizeof(uint64_t) <= sizeof(struct savefpu));
152 static void fpu_clean_state(void);
154 SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD,
155 SYSCTL_NULL_INT_PTR, 1, "Floating point instructions executed in hardware");
157 int use_xsave; /* non-static for cpu_switch.S */
158 uint64_t xsave_mask; /* the same */
159 static uma_zone_t fpu_save_area_zone;
160 static struct savefpu *fpu_initialstate;
162 static struct xsave_area_elm_descr {
168 fpusave_xsaveopt(void *addr)
171 xsaveopt((char *)addr, xsave_mask);
175 fpusave_xsave(void *addr)
178 xsave((char *)addr, xsave_mask);
182 fpurestore_xrstor(void *addr)
185 xrstor((char *)addr, xsave_mask);
189 fpusave_fxsave(void *addr)
192 fxsave((char *)addr);
196 fpurestore_fxrstor(void *addr)
199 fxrstor((char *)addr);
208 if ((cpu_feature2 & CPUID2_XSAVE) == 0)
211 TUNABLE_INT_FETCH("hw.use_xsave", &use_xsave);
214 DEFINE_IFUNC(, void, fpusave, (void *))
219 return ((cpu_stdext_feature & CPUID_EXTSTATE_XSAVEOPT) != 0 ?
220 fpusave_xsaveopt : fpusave_xsave);
221 return (fpusave_fxsave);
224 DEFINE_IFUNC(, void, fpurestore, (void *))
228 return (use_xsave ? fpurestore_xrstor : fpurestore_fxrstor);
232 fpususpend(void *addr)
243 fpuresume(void *addr)
251 load_xcr(XCR0, xsave_mask);
257 * Enable XSAVE if supported and allowed by user.
258 * Calculate the xsave_mask.
264 uint64_t xsave_mask_user;
269 cpuid_count(0xd, 0x0, cp);
270 xsave_mask = XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
271 if ((cp[0] & xsave_mask) != xsave_mask)
272 panic("CPU0 does not support X87 or SSE: %x", cp[0]);
273 xsave_mask = ((uint64_t)cp[3] << 32) | cp[0];
274 xsave_mask_user = xsave_mask;
275 TUNABLE_ULONG_FETCH("hw.xsave_mask", &xsave_mask_user);
276 xsave_mask_user |= XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
277 xsave_mask &= xsave_mask_user;
278 if ((xsave_mask & XFEATURE_AVX512) != XFEATURE_AVX512)
279 xsave_mask &= ~XFEATURE_AVX512;
280 if ((xsave_mask & XFEATURE_MPX) != XFEATURE_MPX)
281 xsave_mask &= ~XFEATURE_MPX;
283 cpuid_count(0xd, 0x1, cp);
284 if ((cp[0] & CPUID_EXTSTATE_XSAVEOPT) != 0) {
286 * Patch the XSAVE instruction in the cpu_switch code
287 * to XSAVEOPT. We assume that XSAVE encoding used
288 * REX byte, and set the bit 4 of the r/m byte.
290 * It seems that some BIOSes give control to the OS
291 * with CR0.WP already set, making the kernel text
292 * read-only before cpu_startup().
294 old_wp = disable_wp();
295 ctx_switch_xsave[3] |= 0x10;
301 * Calculate the fpu save area size.
309 cpuid_count(0xd, 0x0, cp);
310 cpu_max_ext_state_size = cp[1];
313 * Reload the cpu_feature2, since we enabled OSXSAVE.
316 cpu_feature2 = cp[2];
318 cpu_max_ext_state_size = sizeof(struct savefpu);
322 * Initialize the floating point unit.
335 load_cr4(rcr4() | CR4_XSAVE);
336 load_xcr(XCR0, xsave_mask);
340 * XCR0 shall be set up before CPU can report the save area size.
346 * It is too early for critical_enter() to work on AP.
348 saveintr = intr_disable();
351 control = __INITIAL_FPUCW__;
353 mxcsr = __INITIAL_MXCSR__;
356 intr_restore(saveintr);
360 * On the boot CPU we generate a clean state that is used to
361 * initialize the floating point unit when it is first used by a
365 fpuinitstate(void *arg __unused)
369 int cp[4], i, max_ext_n;
371 /* Do potentially blocking operations before disabling interrupts. */
372 fpu_save_area_zone = uma_zcreate("FPU_save_area",
373 cpu_max_ext_state_size, NULL, NULL, NULL, NULL,
374 XSAVE_AREA_ALIGN - 1, 0);
375 fpu_initialstate = uma_zalloc(fpu_save_area_zone, M_WAITOK | M_ZERO);
377 max_ext_n = flsl(xsave_mask);
378 xsave_area_desc = malloc(max_ext_n * sizeof(struct
379 xsave_area_elm_descr), M_DEVBUF, M_WAITOK | M_ZERO);
382 saveintr = intr_disable();
385 fpusave_fxsave(fpu_initialstate);
386 if (fpu_initialstate->sv_env.en_mxcsr_mask)
387 cpu_mxcsr_mask = fpu_initialstate->sv_env.en_mxcsr_mask;
389 cpu_mxcsr_mask = 0xFFBF;
392 * The fninit instruction does not modify XMM registers or x87
393 * registers (MM/ST). The fpusave call dumped the garbage
394 * contained in the registers after reset to the initial state
395 * saved. Clear XMM and x87 registers file image to make the
396 * startup program state and signal handler XMM/x87 register
397 * content predictable.
399 bzero(fpu_initialstate->sv_fp, sizeof(fpu_initialstate->sv_fp));
400 bzero(fpu_initialstate->sv_xmm, sizeof(fpu_initialstate->sv_xmm));
403 * Create a table describing the layout of the CPU Extended
407 xstate_bv = (uint64_t *)((char *)(fpu_initialstate + 1) +
408 offsetof(struct xstate_hdr, xstate_bv));
409 *xstate_bv = XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
412 xsave_area_desc[0].offset = 0;
413 xsave_area_desc[0].size = 160;
415 xsave_area_desc[1].offset = 160;
416 xsave_area_desc[1].size = 288 - 160;
418 for (i = 2; i < max_ext_n; i++) {
419 cpuid_count(0xd, i, cp);
420 xsave_area_desc[i].offset = cp[1];
421 xsave_area_desc[i].size = cp[0];
426 intr_restore(saveintr);
428 /* EFIRT needs this to be initialized before we can enter our EFI environment */
429 SYSINIT(fpuinitstate, SI_SUB_DRIVERS, SI_ORDER_FIRST, fpuinitstate, NULL);
432 * Free coprocessor (if we have it).
435 fpuexit(struct thread *td)
439 if (curthread == PCPU_GET(fpcurthread)) {
441 fpusave(curpcb->pcb_save);
443 PCPU_SET(fpcurthread, NULL);
452 return (_MC_FPFMT_XMM);
456 * The following mechanism is used to ensure that the FPE_... value
457 * that is passed as a trapcode to the signal handler of the user
458 * process does not have more than one bit set.
460 * Multiple bits may be set if the user process modifies the control
461 * word while a status word bit is already set. While this is a sign
462 * of bad coding, we have no choise than to narrow them down to one
463 * bit, since we must not send a trapcode that is not exactly one of
466 * The mechanism has a static table with 127 entries. Each combination
467 * of the 7 FPU status word exception bits directly translates to a
468 * position in this table, where a single FPE_... value is stored.
469 * This FPE_... value stored there is considered the "most important"
470 * of the exception bits and will be sent as the signal code. The
471 * precedence of the bits is based upon Intel Document "Numerical
472 * Applications", Chapter "Special Computational Situations".
474 * The macro to choose one of these values does these steps: 1) Throw
475 * away status word bits that cannot be masked. 2) Throw away the bits
476 * currently masked in the control word, assuming the user isn't
477 * interested in them anymore. 3) Reinsert status word bit 7 (stack
478 * fault) if it is set, which cannot be masked but must be presered.
479 * 4) Use the remaining bits to point into the trapcode table.
481 * The 6 maskable bits in order of their preference, as stated in the
482 * above referenced Intel manual:
483 * 1 Invalid operation (FP_X_INV)
486 * 1c Operand of unsupported format
488 * 2 QNaN operand (not an exception, irrelavant here)
489 * 3 Any other invalid-operation not mentioned above or zero divide
490 * (FP_X_INV, FP_X_DZ)
491 * 4 Denormal operand (FP_X_DNML)
492 * 5 Numeric over/underflow (FP_X_OFL, FP_X_UFL)
493 * 6 Inexact result (FP_X_IMP)
495 static char fpetable[128] = {
497 FPE_FLTINV, /* 1 - INV */
498 FPE_FLTUND, /* 2 - DNML */
499 FPE_FLTINV, /* 3 - INV | DNML */
500 FPE_FLTDIV, /* 4 - DZ */
501 FPE_FLTINV, /* 5 - INV | DZ */
502 FPE_FLTDIV, /* 6 - DNML | DZ */
503 FPE_FLTINV, /* 7 - INV | DNML | DZ */
504 FPE_FLTOVF, /* 8 - OFL */
505 FPE_FLTINV, /* 9 - INV | OFL */
506 FPE_FLTUND, /* A - DNML | OFL */
507 FPE_FLTINV, /* B - INV | DNML | OFL */
508 FPE_FLTDIV, /* C - DZ | OFL */
509 FPE_FLTINV, /* D - INV | DZ | OFL */
510 FPE_FLTDIV, /* E - DNML | DZ | OFL */
511 FPE_FLTINV, /* F - INV | DNML | DZ | OFL */
512 FPE_FLTUND, /* 10 - UFL */
513 FPE_FLTINV, /* 11 - INV | UFL */
514 FPE_FLTUND, /* 12 - DNML | UFL */
515 FPE_FLTINV, /* 13 - INV | DNML | UFL */
516 FPE_FLTDIV, /* 14 - DZ | UFL */
517 FPE_FLTINV, /* 15 - INV | DZ | UFL */
518 FPE_FLTDIV, /* 16 - DNML | DZ | UFL */
519 FPE_FLTINV, /* 17 - INV | DNML | DZ | UFL */
520 FPE_FLTOVF, /* 18 - OFL | UFL */
521 FPE_FLTINV, /* 19 - INV | OFL | UFL */
522 FPE_FLTUND, /* 1A - DNML | OFL | UFL */
523 FPE_FLTINV, /* 1B - INV | DNML | OFL | UFL */
524 FPE_FLTDIV, /* 1C - DZ | OFL | UFL */
525 FPE_FLTINV, /* 1D - INV | DZ | OFL | UFL */
526 FPE_FLTDIV, /* 1E - DNML | DZ | OFL | UFL */
527 FPE_FLTINV, /* 1F - INV | DNML | DZ | OFL | UFL */
528 FPE_FLTRES, /* 20 - IMP */
529 FPE_FLTINV, /* 21 - INV | IMP */
530 FPE_FLTUND, /* 22 - DNML | IMP */
531 FPE_FLTINV, /* 23 - INV | DNML | IMP */
532 FPE_FLTDIV, /* 24 - DZ | IMP */
533 FPE_FLTINV, /* 25 - INV | DZ | IMP */
534 FPE_FLTDIV, /* 26 - DNML | DZ | IMP */
535 FPE_FLTINV, /* 27 - INV | DNML | DZ | IMP */
536 FPE_FLTOVF, /* 28 - OFL | IMP */
537 FPE_FLTINV, /* 29 - INV | OFL | IMP */
538 FPE_FLTUND, /* 2A - DNML | OFL | IMP */
539 FPE_FLTINV, /* 2B - INV | DNML | OFL | IMP */
540 FPE_FLTDIV, /* 2C - DZ | OFL | IMP */
541 FPE_FLTINV, /* 2D - INV | DZ | OFL | IMP */
542 FPE_FLTDIV, /* 2E - DNML | DZ | OFL | IMP */
543 FPE_FLTINV, /* 2F - INV | DNML | DZ | OFL | IMP */
544 FPE_FLTUND, /* 30 - UFL | IMP */
545 FPE_FLTINV, /* 31 - INV | UFL | IMP */
546 FPE_FLTUND, /* 32 - DNML | UFL | IMP */
547 FPE_FLTINV, /* 33 - INV | DNML | UFL | IMP */
548 FPE_FLTDIV, /* 34 - DZ | UFL | IMP */
549 FPE_FLTINV, /* 35 - INV | DZ | UFL | IMP */
550 FPE_FLTDIV, /* 36 - DNML | DZ | UFL | IMP */
551 FPE_FLTINV, /* 37 - INV | DNML | DZ | UFL | IMP */
552 FPE_FLTOVF, /* 38 - OFL | UFL | IMP */
553 FPE_FLTINV, /* 39 - INV | OFL | UFL | IMP */
554 FPE_FLTUND, /* 3A - DNML | OFL | UFL | IMP */
555 FPE_FLTINV, /* 3B - INV | DNML | OFL | UFL | IMP */
556 FPE_FLTDIV, /* 3C - DZ | OFL | UFL | IMP */
557 FPE_FLTINV, /* 3D - INV | DZ | OFL | UFL | IMP */
558 FPE_FLTDIV, /* 3E - DNML | DZ | OFL | UFL | IMP */
559 FPE_FLTINV, /* 3F - INV | DNML | DZ | OFL | UFL | IMP */
560 FPE_FLTSUB, /* 40 - STK */
561 FPE_FLTSUB, /* 41 - INV | STK */
562 FPE_FLTUND, /* 42 - DNML | STK */
563 FPE_FLTSUB, /* 43 - INV | DNML | STK */
564 FPE_FLTDIV, /* 44 - DZ | STK */
565 FPE_FLTSUB, /* 45 - INV | DZ | STK */
566 FPE_FLTDIV, /* 46 - DNML | DZ | STK */
567 FPE_FLTSUB, /* 47 - INV | DNML | DZ | STK */
568 FPE_FLTOVF, /* 48 - OFL | STK */
569 FPE_FLTSUB, /* 49 - INV | OFL | STK */
570 FPE_FLTUND, /* 4A - DNML | OFL | STK */
571 FPE_FLTSUB, /* 4B - INV | DNML | OFL | STK */
572 FPE_FLTDIV, /* 4C - DZ | OFL | STK */
573 FPE_FLTSUB, /* 4D - INV | DZ | OFL | STK */
574 FPE_FLTDIV, /* 4E - DNML | DZ | OFL | STK */
575 FPE_FLTSUB, /* 4F - INV | DNML | DZ | OFL | STK */
576 FPE_FLTUND, /* 50 - UFL | STK */
577 FPE_FLTSUB, /* 51 - INV | UFL | STK */
578 FPE_FLTUND, /* 52 - DNML | UFL | STK */
579 FPE_FLTSUB, /* 53 - INV | DNML | UFL | STK */
580 FPE_FLTDIV, /* 54 - DZ | UFL | STK */
581 FPE_FLTSUB, /* 55 - INV | DZ | UFL | STK */
582 FPE_FLTDIV, /* 56 - DNML | DZ | UFL | STK */
583 FPE_FLTSUB, /* 57 - INV | DNML | DZ | UFL | STK */
584 FPE_FLTOVF, /* 58 - OFL | UFL | STK */
585 FPE_FLTSUB, /* 59 - INV | OFL | UFL | STK */
586 FPE_FLTUND, /* 5A - DNML | OFL | UFL | STK */
587 FPE_FLTSUB, /* 5B - INV | DNML | OFL | UFL | STK */
588 FPE_FLTDIV, /* 5C - DZ | OFL | UFL | STK */
589 FPE_FLTSUB, /* 5D - INV | DZ | OFL | UFL | STK */
590 FPE_FLTDIV, /* 5E - DNML | DZ | OFL | UFL | STK */
591 FPE_FLTSUB, /* 5F - INV | DNML | DZ | OFL | UFL | STK */
592 FPE_FLTRES, /* 60 - IMP | STK */
593 FPE_FLTSUB, /* 61 - INV | IMP | STK */
594 FPE_FLTUND, /* 62 - DNML | IMP | STK */
595 FPE_FLTSUB, /* 63 - INV | DNML | IMP | STK */
596 FPE_FLTDIV, /* 64 - DZ | IMP | STK */
597 FPE_FLTSUB, /* 65 - INV | DZ | IMP | STK */
598 FPE_FLTDIV, /* 66 - DNML | DZ | IMP | STK */
599 FPE_FLTSUB, /* 67 - INV | DNML | DZ | IMP | STK */
600 FPE_FLTOVF, /* 68 - OFL | IMP | STK */
601 FPE_FLTSUB, /* 69 - INV | OFL | IMP | STK */
602 FPE_FLTUND, /* 6A - DNML | OFL | IMP | STK */
603 FPE_FLTSUB, /* 6B - INV | DNML | OFL | IMP | STK */
604 FPE_FLTDIV, /* 6C - DZ | OFL | IMP | STK */
605 FPE_FLTSUB, /* 6D - INV | DZ | OFL | IMP | STK */
606 FPE_FLTDIV, /* 6E - DNML | DZ | OFL | IMP | STK */
607 FPE_FLTSUB, /* 6F - INV | DNML | DZ | OFL | IMP | STK */
608 FPE_FLTUND, /* 70 - UFL | IMP | STK */
609 FPE_FLTSUB, /* 71 - INV | UFL | IMP | STK */
610 FPE_FLTUND, /* 72 - DNML | UFL | IMP | STK */
611 FPE_FLTSUB, /* 73 - INV | DNML | UFL | IMP | STK */
612 FPE_FLTDIV, /* 74 - DZ | UFL | IMP | STK */
613 FPE_FLTSUB, /* 75 - INV | DZ | UFL | IMP | STK */
614 FPE_FLTDIV, /* 76 - DNML | DZ | UFL | IMP | STK */
615 FPE_FLTSUB, /* 77 - INV | DNML | DZ | UFL | IMP | STK */
616 FPE_FLTOVF, /* 78 - OFL | UFL | IMP | STK */
617 FPE_FLTSUB, /* 79 - INV | OFL | UFL | IMP | STK */
618 FPE_FLTUND, /* 7A - DNML | OFL | UFL | IMP | STK */
619 FPE_FLTSUB, /* 7B - INV | DNML | OFL | UFL | IMP | STK */
620 FPE_FLTDIV, /* 7C - DZ | OFL | UFL | IMP | STK */
621 FPE_FLTSUB, /* 7D - INV | DZ | OFL | UFL | IMP | STK */
622 FPE_FLTDIV, /* 7E - DNML | DZ | OFL | UFL | IMP | STK */
623 FPE_FLTSUB, /* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */
627 * Read the FP status and control words, then generate si_code value
628 * for SIGFPE. The error code chosen will be one of the
629 * FPE_... macros. It will be sent as the second argument to old
630 * BSD-style signal handlers and as "siginfo_t->si_code" (second
631 * argument) to SA_SIGINFO signal handlers.
633 * Some time ago, we cleared the x87 exceptions with FNCLEX there.
634 * Clearing exceptions was necessary mainly to avoid IRQ13 bugs. The
635 * usermode code which understands the FPU hardware enough to enable
636 * the exceptions, can also handle clearing the exception state in the
637 * handler. The only consequence of not clearing the exception is the
638 * rethrow of the SIGFPE on return from the signal handler and
639 * reexecution of the corresponding instruction.
641 * For XMM traps, the exceptions were never cleared.
646 struct savefpu *pcb_save;
647 u_short control, status;
652 * Interrupt handling (for another interrupt) may have pushed the
653 * state to memory. Fetch the relevant parts of the state from
656 if (PCPU_GET(fpcurthread) != curthread) {
657 pcb_save = curpcb->pcb_save;
658 control = pcb_save->sv_env.en_cw;
659 status = pcb_save->sv_env.en_sw;
666 return (fpetable[status & ((~control & 0x3f) | 0x40)]);
675 if (PCPU_GET(fpcurthread) != curthread)
676 mxcsr = curpcb->pcb_save->sv_env.en_mxcsr;
680 return (fpetable[(mxcsr & (~mxcsr >> 7)) & 0x3f]);
684 restore_fpu_curthread(struct thread *td)
689 * Record new context early in case frstor causes a trap.
691 PCPU_SET(fpcurthread, td);
697 if ((pcb->pcb_flags & PCB_FPUINITDONE) == 0) {
699 * This is the first time this thread has used the FPU or
700 * the PCB doesn't contain a clean FPU state. Explicitly
701 * load an initial state.
703 * We prefer to restore the state from the actual save
704 * area in PCB instead of directly loading from
705 * fpu_initialstate, to ignite the XSAVEOPT
708 bcopy(fpu_initialstate, pcb->pcb_save,
709 cpu_max_ext_state_size);
710 fpurestore(pcb->pcb_save);
711 if (pcb->pcb_initial_fpucw != __INITIAL_FPUCW__)
712 fldcw(pcb->pcb_initial_fpucw);
713 if (PCB_USER_FPU(pcb))
714 set_pcb_flags(pcb, PCB_FPUINITDONE |
715 PCB_USERFPUINITDONE);
717 set_pcb_flags(pcb, PCB_FPUINITDONE);
719 fpurestore(pcb->pcb_save);
723 * Device Not Available (DNA, #NM) exception handler.
725 * It would be better to switch FP context here (if curthread !=
726 * fpcurthread) and not necessarily for every context switch, but it
727 * is too hard to access foreign pcb's.
736 * This handler is entered with interrupts enabled, so context
737 * switches may occur before critical_enter() is executed. If
738 * a context switch occurs, then when we regain control, our
739 * state will have been completely restored. The CPU may
740 * change underneath us, but the only part of our context that
741 * lives in the CPU is CR0.TS and that will be "restored" by
742 * setting it on the new CPU.
746 KASSERT((curpcb->pcb_flags & PCB_FPUNOSAVE) == 0,
747 ("fpudna while in fpu_kern_enter(FPU_KERN_NOCTX)"));
748 if (__predict_false(PCPU_GET(fpcurthread) == td)) {
750 * Some virtual machines seems to set %cr0.TS at
751 * arbitrary moments. Silently clear the TS bit
752 * regardless of the eager/lazy FPU context switch
757 if (__predict_false(PCPU_GET(fpcurthread) != NULL)) {
759 "fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
760 PCPU_GET(fpcurthread),
761 PCPU_GET(fpcurthread)->td_tid, td, td->td_tid);
763 restore_fpu_curthread(td);
768 void fpu_activate_sw(struct thread *td); /* Called from the context switch */
770 fpu_activate_sw(struct thread *td)
773 if ((td->td_pflags & TDP_KTHREAD) != 0 || !PCB_USER_FPU(td->td_pcb)) {
774 PCPU_SET(fpcurthread, NULL);
776 } else if (PCPU_GET(fpcurthread) != td) {
777 restore_fpu_curthread(td);
786 td = PCPU_GET(fpcurthread);
787 KASSERT(td == curthread, ("fpudrop: fpcurthread != curthread"));
789 PCPU_SET(fpcurthread, NULL);
790 clear_pcb_flags(td->td_pcb, PCB_FPUINITDONE);
795 * Get the user state of the FPU into pcb->pcb_user_save without
796 * dropping ownership (if possible). It returns the FPU ownership
800 fpugetregs(struct thread *td)
803 uint64_t *xstate_bv, bit;
805 int max_ext_n, i, owned;
809 if ((pcb->pcb_flags & PCB_USERFPUINITDONE) == 0) {
810 bcopy(fpu_initialstate, get_pcb_user_save_pcb(pcb),
811 cpu_max_ext_state_size);
812 get_pcb_user_save_pcb(pcb)->sv_env.en_cw =
813 pcb->pcb_initial_fpucw;
816 return (_MC_FPOWNED_PCB);
818 if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
819 fpusave(get_pcb_user_save_pcb(pcb));
820 owned = _MC_FPOWNED_FPU;
822 owned = _MC_FPOWNED_PCB;
826 * Handle partially saved state.
828 sa = (char *)get_pcb_user_save_pcb(pcb);
829 xstate_bv = (uint64_t *)(sa + sizeof(struct savefpu) +
830 offsetof(struct xstate_hdr, xstate_bv));
831 max_ext_n = flsl(xsave_mask);
832 for (i = 0; i < max_ext_n; i++) {
834 if ((xsave_mask & bit) == 0 || (*xstate_bv & bit) != 0)
836 bcopy((char *)fpu_initialstate +
837 xsave_area_desc[i].offset,
838 sa + xsave_area_desc[i].offset,
839 xsave_area_desc[i].size);
848 fpuuserinited(struct thread *td)
854 if (PCB_USER_FPU(pcb))
856 PCB_FPUINITDONE | PCB_USERFPUINITDONE);
858 set_pcb_flags(pcb, PCB_FPUINITDONE);
862 fpusetxstate(struct thread *td, char *xfpustate, size_t xfpustate_size)
864 struct xstate_hdr *hdr, *ehdr;
868 /* XXXKIB should we clear all extended state in xstate_bv instead ? */
869 if (xfpustate == NULL)
874 len = xfpustate_size;
875 if (len < sizeof(struct xstate_hdr))
877 max_len = cpu_max_ext_state_size - sizeof(struct savefpu);
881 ehdr = (struct xstate_hdr *)xfpustate;
882 bv = ehdr->xstate_bv;
887 if (bv & ~xsave_mask)
890 hdr = (struct xstate_hdr *)(get_pcb_user_save_td(td) + 1);
893 bcopy(xfpustate + sizeof(struct xstate_hdr),
894 (char *)(hdr + 1), len - sizeof(struct xstate_hdr));
900 * Set the state of the FPU.
903 fpusetregs(struct thread *td, struct savefpu *addr, char *xfpustate,
904 size_t xfpustate_size)
909 addr->sv_env.en_mxcsr &= cpu_mxcsr_mask;
913 if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
914 error = fpusetxstate(td, xfpustate, xfpustate_size);
916 bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
917 fpurestore(get_pcb_user_save_td(td));
918 set_pcb_flags(pcb, PCB_FPUINITDONE |
919 PCB_USERFPUINITDONE);
922 error = fpusetxstate(td, xfpustate, xfpustate_size);
924 bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
933 * On AuthenticAMD processors, the fxrstor instruction does not restore
934 * the x87's stored last instruction pointer, last data pointer, and last
935 * opcode values, except in the rare case in which the exception summary
936 * (ES) bit in the x87 status word is set to 1.
938 * In order to avoid leaking this information across processes, we clean
939 * these values by performing a dummy load before executing fxrstor().
942 fpu_clean_state(void)
944 static float dummy_variable = 0.0;
948 * Clear the ES bit in the x87 status word if it is currently
949 * set, in order to avoid causing a fault in the upcoming load.
956 * Load the dummy variable into the x87 stack. This mangles
957 * the x87 stack, but we don't care since we're about to call
960 __asm __volatile("ffree %%st(7); flds %0" : : "m" (dummy_variable));
964 * This really sucks. We want the acpi version only, but it requires
965 * the isa_if.h file in order to get the definitions.
969 #include <isa/isavar.h>
971 * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI.
973 static struct isa_pnp_id fpupnp_ids[] = {
974 { 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
979 fpupnp_probe(device_t dev)
983 result = ISA_PNP_PROBE(device_get_parent(dev), dev, fpupnp_ids);
990 fpupnp_attach(device_t dev)
996 static device_method_t fpupnp_methods[] = {
997 /* Device interface */
998 DEVMETHOD(device_probe, fpupnp_probe),
999 DEVMETHOD(device_attach, fpupnp_attach),
1000 DEVMETHOD(device_detach, bus_generic_detach),
1001 DEVMETHOD(device_shutdown, bus_generic_shutdown),
1002 DEVMETHOD(device_suspend, bus_generic_suspend),
1003 DEVMETHOD(device_resume, bus_generic_resume),
1008 static driver_t fpupnp_driver = {
1014 static devclass_t fpupnp_devclass;
1016 DRIVER_MODULE(fpupnp, acpi, fpupnp_driver, fpupnp_devclass, 0, 0);
1017 ISA_PNP_INFO(fpupnp_ids);
1018 #endif /* DEV_ISA */
1020 static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx",
1021 "Kernel contexts for FPU state");
1023 #define FPU_KERN_CTX_FPUINITDONE 0x01
1024 #define FPU_KERN_CTX_DUMMY 0x02 /* avoided save for the kern thread */
1025 #define FPU_KERN_CTX_INUSE 0x04
1027 struct fpu_kern_ctx {
1028 struct savefpu *prev;
1033 struct fpu_kern_ctx *
1034 fpu_kern_alloc_ctx(u_int flags)
1036 struct fpu_kern_ctx *res;
1039 sz = sizeof(struct fpu_kern_ctx) + XSAVE_AREA_ALIGN +
1040 cpu_max_ext_state_size;
1041 res = malloc(sz, M_FPUKERN_CTX, ((flags & FPU_KERN_NOWAIT) ?
1042 M_NOWAIT : M_WAITOK) | M_ZERO);
1047 fpu_kern_free_ctx(struct fpu_kern_ctx *ctx)
1050 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) == 0, ("free'ing inuse ctx"));
1051 /* XXXKIB clear the memory ? */
1052 free(ctx, M_FPUKERN_CTX);
1055 static struct savefpu *
1056 fpu_kern_ctx_savefpu(struct fpu_kern_ctx *ctx)
1060 p = (vm_offset_t)&ctx->hwstate1;
1061 p = roundup2(p, XSAVE_AREA_ALIGN);
1062 return ((struct savefpu *)p);
1066 fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags)
1071 KASSERT((flags & FPU_KERN_NOCTX) != 0 || ctx != NULL,
1072 ("ctx is required when !FPU_KERN_NOCTX"));
1073 KASSERT(ctx == NULL || (ctx->flags & FPU_KERN_CTX_INUSE) == 0,
1074 ("using inuse ctx"));
1075 KASSERT((pcb->pcb_flags & PCB_FPUNOSAVE) == 0,
1076 ("recursive fpu_kern_enter while in PCB_FPUNOSAVE state"));
1078 if ((flags & FPU_KERN_NOCTX) != 0) {
1081 if (curthread == PCPU_GET(fpcurthread)) {
1082 fpusave(curpcb->pcb_save);
1083 PCPU_SET(fpcurthread, NULL);
1085 KASSERT(PCPU_GET(fpcurthread) == NULL,
1086 ("invalid fpcurthread"));
1090 * This breaks XSAVEOPT tracker, but
1091 * PCB_FPUNOSAVE state is supposed to never need to
1092 * save FPU context at all.
1094 fpurestore(fpu_initialstate);
1095 set_pcb_flags(pcb, PCB_KERNFPU | PCB_FPUNOSAVE |
1099 if ((flags & FPU_KERN_KTHR) != 0 && is_fpu_kern_thread(0)) {
1100 ctx->flags = FPU_KERN_CTX_DUMMY | FPU_KERN_CTX_INUSE;
1104 KASSERT(!PCB_USER_FPU(pcb) || pcb->pcb_save ==
1105 get_pcb_user_save_pcb(pcb), ("mangled pcb_save"));
1106 ctx->flags = FPU_KERN_CTX_INUSE;
1107 if ((pcb->pcb_flags & PCB_FPUINITDONE) != 0)
1108 ctx->flags |= FPU_KERN_CTX_FPUINITDONE;
1110 ctx->prev = pcb->pcb_save;
1111 pcb->pcb_save = fpu_kern_ctx_savefpu(ctx);
1112 set_pcb_flags(pcb, PCB_KERNFPU);
1113 clear_pcb_flags(pcb, PCB_FPUINITDONE);
1118 fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx)
1124 if ((pcb->pcb_flags & PCB_FPUNOSAVE) != 0) {
1125 KASSERT(ctx == NULL, ("non-null ctx after FPU_KERN_NOCTX"));
1126 KASSERT(PCPU_GET(fpcurthread) == NULL,
1127 ("non-NULL fpcurthread for PCB_FPUNOSAVE"));
1128 CRITICAL_ASSERT(td);
1130 clear_pcb_flags(pcb, PCB_FPUNOSAVE | PCB_FPUINITDONE);
1133 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) != 0,
1134 ("leaving not inuse ctx"));
1135 ctx->flags &= ~FPU_KERN_CTX_INUSE;
1137 if (is_fpu_kern_thread(0) &&
1138 (ctx->flags & FPU_KERN_CTX_DUMMY) != 0)
1140 KASSERT((ctx->flags & FPU_KERN_CTX_DUMMY) == 0,
1143 if (curthread == PCPU_GET(fpcurthread))
1145 pcb->pcb_save = ctx->prev;
1148 if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) {
1149 if ((pcb->pcb_flags & PCB_USERFPUINITDONE) != 0) {
1150 set_pcb_flags(pcb, PCB_FPUINITDONE);
1151 clear_pcb_flags(pcb, PCB_KERNFPU);
1153 clear_pcb_flags(pcb, PCB_FPUINITDONE | PCB_KERNFPU);
1155 if ((ctx->flags & FPU_KERN_CTX_FPUINITDONE) != 0)
1156 set_pcb_flags(pcb, PCB_FPUINITDONE);
1158 clear_pcb_flags(pcb, PCB_FPUINITDONE);
1159 KASSERT(!PCB_USER_FPU(pcb), ("unpaired fpu_kern_leave"));
1166 fpu_kern_thread(u_int flags)
1169 KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0,
1170 ("Only kthread may use fpu_kern_thread"));
1171 KASSERT(curpcb->pcb_save == get_pcb_user_save_pcb(curpcb),
1172 ("mangled pcb_save"));
1173 KASSERT(PCB_USER_FPU(curpcb), ("recursive call"));
1175 set_pcb_flags(curpcb, PCB_KERNFPU);
1180 is_fpu_kern_thread(u_int flags)
1183 if ((curthread->td_pflags & TDP_KTHREAD) == 0)
1185 return ((curpcb->pcb_flags & PCB_KERNFPU) != 0);
1189 * FPU save area alloc/free/init utility routines
1192 fpu_save_area_alloc(void)
1195 return (uma_zalloc(fpu_save_area_zone, M_WAITOK));
1199 fpu_save_area_free(struct savefpu *fsa)
1202 uma_zfree(fpu_save_area_zone, fsa);
1206 fpu_save_area_reset(struct savefpu *fsa)
1209 bcopy(fpu_initialstate, fsa, cpu_max_ext_state_size);