xref: /freebsd/sys/i386/i386/vm_machdep.c (revision 037479ff5ee18977b1c48e1e59770aad2f200a5a)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1982, 1986 The Regents of the University of California.
5  * Copyright (c) 1989, 1990 William Jolitz
6  * Copyright (c) 1994 John Dyson
7  * All rights reserved.
8  *
9  * This code is derived from software contributed to Berkeley by
10  * the Systems Programming Group of the University of Utah Computer
11  * Science Department, and William Jolitz.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by the University of
24  *	California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	from: @(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
42  *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
43  */
44 
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include "opt_isa.h"
49 #include "opt_npx.h"
50 #include "opt_reset.h"
51 #include "opt_cpu.h"
52 
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/bio.h>
56 #include <sys/buf.h>
57 #include <sys/kernel.h>
58 #include <sys/ktr.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mbuf.h>
62 #include <sys/mutex.h>
63 #include <sys/pioctl.h>
64 #include <sys/proc.h>
65 #include <sys/sysent.h>
66 #include <sys/sf_buf.h>
67 #include <sys/smp.h>
68 #include <sys/sched.h>
69 #include <sys/sysctl.h>
70 #include <sys/unistd.h>
71 #include <sys/vnode.h>
72 #include <sys/vmmeter.h>
73 
74 #include <machine/cpu.h>
75 #include <machine/cputypes.h>
76 #include <machine/md_var.h>
77 #include <machine/pcb.h>
78 #include <machine/pcb_ext.h>
79 #include <machine/smp.h>
80 #include <machine/vm86.h>
81 
82 #include <vm/vm.h>
83 #include <vm/vm_extern.h>
84 #include <vm/vm_kern.h>
85 #include <vm/vm_page.h>
86 #include <vm/vm_map.h>
87 #include <vm/vm_param.h>
88 
89 #ifndef NSFBUFS
90 #define	NSFBUFS		(512 + maxusers * 16)
91 #endif
92 
93 _Static_assert(OFFSETOF_CURTHREAD == offsetof(struct pcpu, pc_curthread),
94     "OFFSETOF_CURTHREAD does not correspond with offset of pc_curthread.");
95 _Static_assert(OFFSETOF_CURPCB == offsetof(struct pcpu, pc_curpcb),
96     "OFFSETOF_CURPCB does not correspond with offset of pc_curpcb.");
97 _Static_assert(__OFFSETOF_MONITORBUF == offsetof(struct pcpu, pc_monitorbuf),
98     "__OFFSETOF_MONINORBUF does not correspond with offset of pc_monitorbuf.");
99 
100 union savefpu *
101 get_pcb_user_save_td(struct thread *td)
102 {
103 	vm_offset_t p;
104 
105 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
106 	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
107 	KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
108 	return ((union savefpu *)p);
109 }
110 
111 union savefpu *
112 get_pcb_user_save_pcb(struct pcb *pcb)
113 {
114 	vm_offset_t p;
115 
116 	p = (vm_offset_t)(pcb + 1);
117 	return ((union savefpu *)p);
118 }
119 
120 struct pcb *
121 get_pcb_td(struct thread *td)
122 {
123 	vm_offset_t p;
124 
125 	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
126 	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
127 	    sizeof(struct pcb);
128 	return ((struct pcb *)p);
129 }
130 
131 void *
132 alloc_fpusave(int flags)
133 {
134 	void *res;
135 	struct savefpu_ymm *sf;
136 
137 	res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags);
138 	if (use_xsave) {
139 		sf = (struct savefpu_ymm *)res;
140 		bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd));
141 		sf->sv_xstate.sx_hd.xstate_bv = xsave_mask;
142 	}
143 	return (res);
144 }
145 /*
146  * Finish a fork operation, with process p2 nearly set up.
147  * Copy and update the pcb, set up the stack so that the child
148  * ready to run and return to user mode.
149  */
150 void
151 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
152 {
153 	struct proc *p1;
154 	struct pcb *pcb2;
155 	struct mdproc *mdp2;
156 
157 	p1 = td1->td_proc;
158 	if ((flags & RFPROC) == 0) {
159 		if ((flags & RFMEM) == 0) {
160 			/* unshare user LDT */
161 			struct mdproc *mdp1 = &p1->p_md;
162 			struct proc_ldt *pldt, *pldt1;
163 
164 			mtx_lock_spin(&dt_lock);
165 			if ((pldt1 = mdp1->md_ldt) != NULL &&
166 			    pldt1->ldt_refcnt > 1) {
167 				pldt = user_ldt_alloc(mdp1, pldt1->ldt_len);
168 				if (pldt == NULL)
169 					panic("could not copy LDT");
170 				mdp1->md_ldt = pldt;
171 				set_user_ldt(mdp1);
172 				user_ldt_deref(pldt1);
173 			} else
174 				mtx_unlock_spin(&dt_lock);
175 		}
176 		return;
177 	}
178 
179 	/* Ensure that td1's pcb is up to date. */
180 	if (td1 == curthread)
181 		td1->td_pcb->pcb_gs = rgs();
182 	critical_enter();
183 	if (PCPU_GET(fpcurthread) == td1)
184 		npxsave(td1->td_pcb->pcb_save);
185 	critical_exit();
186 
187 	/* Point the pcb to the top of the stack */
188 	pcb2 = get_pcb_td(td2);
189 	td2->td_pcb = pcb2;
190 
191 	/* Copy td1's pcb */
192 	bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
193 
194 	/* Properly initialize pcb_save */
195 	pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
196 	bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2),
197 	    cpu_max_ext_state_size);
198 
199 	/* Point mdproc and then copy over td1's contents */
200 	mdp2 = &p2->p_md;
201 	bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
202 
203 	/*
204 	 * Create a new fresh stack for the new process.
205 	 * Copy the trap frame for the return to user mode as if from a
206 	 * syscall.  This copies most of the user mode register values.
207 	 * The -VM86_STACK_SPACE (-16) is so we can expand the trapframe
208 	 * if we go to vm86.
209 	 */
210 	td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb -
211 	    VM86_STACK_SPACE) - 1;
212 	bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
213 
214 	td2->td_frame->tf_eax = 0;		/* Child returns zero */
215 	td2->td_frame->tf_eflags &= ~PSL_C;	/* success */
216 	td2->td_frame->tf_edx = 1;
217 
218 	/*
219 	 * If the parent process has the trap bit set (i.e. a debugger had
220 	 * single stepped the process to the system call), we need to clear
221 	 * the trap flag from the new frame unless the debugger had set PF_FORK
222 	 * on the parent.  Otherwise, the child will receive a (likely
223 	 * unexpected) SIGTRAP when it executes the first instruction after
224 	 * returning  to userland.
225 	 */
226 	if ((p1->p_pfsflags & PF_FORK) == 0)
227 		td2->td_frame->tf_eflags &= ~PSL_T;
228 
229 	/*
230 	 * Set registers for trampoline to user mode.  Leave space for the
231 	 * return address on stack.  These are the kernel mode register values.
232 	 */
233 #if defined(PAE) || defined(PAE_TABLES)
234 	pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
235 #else
236 	pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
237 #endif
238 	pcb2->pcb_edi = 0;
239 	pcb2->pcb_esi = (int)fork_return;	/* fork_trampoline argument */
240 	pcb2->pcb_ebp = 0;
241 	pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
242 	pcb2->pcb_ebx = (int)td2;		/* fork_trampoline argument */
243 	pcb2->pcb_eip = (int)fork_trampoline + setidt_disp;
244 	/*-
245 	 * pcb2->pcb_dr*:	cloned above.
246 	 * pcb2->pcb_savefpu:	cloned above.
247 	 * pcb2->pcb_flags:	cloned above.
248 	 * pcb2->pcb_onfault:	cloned above (always NULL here?).
249 	 * pcb2->pcb_gs:	cloned above.
250 	 * pcb2->pcb_ext:	cleared below.
251 	 */
252 
253 	/*
254 	 * XXX don't copy the i/o pages.  this should probably be fixed.
255 	 */
256 	pcb2->pcb_ext = 0;
257 
258 	/* Copy the LDT, if necessary. */
259 	mtx_lock_spin(&dt_lock);
260 	if (mdp2->md_ldt != NULL) {
261 		if (flags & RFMEM) {
262 			mdp2->md_ldt->ldt_refcnt++;
263 		} else {
264 			mdp2->md_ldt = user_ldt_alloc(mdp2,
265 			    mdp2->md_ldt->ldt_len);
266 			if (mdp2->md_ldt == NULL)
267 				panic("could not copy LDT");
268 		}
269 	}
270 	mtx_unlock_spin(&dt_lock);
271 
272 	/* Setup to release spin count in fork_exit(). */
273 	td2->td_md.md_spinlock_count = 1;
274 	td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
275 
276 	/*
277 	 * Now, cpu_switch() can schedule the new process.
278 	 * pcb_esp is loaded pointing to the cpu_switch() stack frame
279 	 * containing the return address when exiting cpu_switch.
280 	 * This will normally be to fork_trampoline(), which will have
281 	 * %ebx loaded with the new proc's pointer.  fork_trampoline()
282 	 * will set up a stack to call fork_return(p, frame); to complete
283 	 * the return to user-mode.
284 	 */
285 }
286 
287 /*
288  * Intercept the return address from a freshly forked process that has NOT
289  * been scheduled yet.
290  *
291  * This is needed to make kernel threads stay in kernel mode.
292  */
293 void
294 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg)
295 {
296 	/*
297 	 * Note that the trap frame follows the args, so the function
298 	 * is really called like this:  func(arg, frame);
299 	 */
300 	td->td_pcb->pcb_esi = (int) func;	/* function */
301 	td->td_pcb->pcb_ebx = (int) arg;	/* first arg */
302 }
303 
304 void
305 cpu_exit(struct thread *td)
306 {
307 
308 	/*
309 	 * If this process has a custom LDT, release it.  Reset pc->pcb_gs
310 	 * and %gs before we free it in case they refer to an LDT entry.
311 	 */
312 	mtx_lock_spin(&dt_lock);
313 	if (td->td_proc->p_md.md_ldt) {
314 		td->td_pcb->pcb_gs = _udatasel;
315 		load_gs(_udatasel);
316 		user_ldt_free(td);
317 	} else
318 		mtx_unlock_spin(&dt_lock);
319 }
320 
321 void
322 cpu_thread_exit(struct thread *td)
323 {
324 
325 	critical_enter();
326 	if (td == PCPU_GET(fpcurthread))
327 		npxdrop();
328 	critical_exit();
329 
330 	/* Disable any hardware breakpoints. */
331 	if (td->td_pcb->pcb_flags & PCB_DBREGS) {
332 		reset_dbregs();
333 		td->td_pcb->pcb_flags &= ~PCB_DBREGS;
334 	}
335 }
336 
337 void
338 cpu_thread_clean(struct thread *td)
339 {
340 	struct pcb *pcb;
341 
342 	pcb = td->td_pcb;
343 	if (pcb->pcb_ext != NULL) {
344 		/* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
345 		/*
346 		 * XXX do we need to move the TSS off the allocated pages
347 		 * before freeing them?  (not done here)
348 		 */
349 		pmap_trm_free(pcb->pcb_ext, ctob(IOPAGES + 1));
350 		pcb->pcb_ext = NULL;
351 	}
352 }
353 
354 void
355 cpu_thread_swapin(struct thread *td)
356 {
357 }
358 
359 void
360 cpu_thread_swapout(struct thread *td)
361 {
362 }
363 
364 void
365 cpu_thread_alloc(struct thread *td)
366 {
367 	struct pcb *pcb;
368 	struct xstate_hdr *xhdr;
369 
370 	td->td_pcb = pcb = get_pcb_td(td);
371 	td->td_frame = (struct trapframe *)((caddr_t)pcb -
372 	    VM86_STACK_SPACE) - 1;
373 	pcb->pcb_ext = NULL;
374 	pcb->pcb_save = get_pcb_user_save_pcb(pcb);
375 	if (use_xsave) {
376 		xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1);
377 		bzero(xhdr, sizeof(*xhdr));
378 		xhdr->xstate_bv = xsave_mask;
379 	}
380 }
381 
382 void
383 cpu_thread_free(struct thread *td)
384 {
385 
386 	cpu_thread_clean(td);
387 }
388 
389 void
390 cpu_set_syscall_retval(struct thread *td, int error)
391 {
392 
393 	switch (error) {
394 	case 0:
395 		td->td_frame->tf_eax = td->td_retval[0];
396 		td->td_frame->tf_edx = td->td_retval[1];
397 		td->td_frame->tf_eflags &= ~PSL_C;
398 		break;
399 
400 	case ERESTART:
401 		/*
402 		 * Reconstruct pc, assuming lcall $X,y is 7 bytes, int
403 		 * 0x80 is 2 bytes. We saved this in tf_err.
404 		 */
405 		td->td_frame->tf_eip -= td->td_frame->tf_err;
406 		break;
407 
408 	case EJUSTRETURN:
409 		break;
410 
411 	default:
412 		td->td_frame->tf_eax = SV_ABI_ERRNO(td->td_proc, error);
413 		td->td_frame->tf_eflags |= PSL_C;
414 		break;
415 	}
416 }
417 
418 /*
419  * Initialize machine state, mostly pcb and trap frame for a new
420  * thread, about to return to userspace.  Put enough state in the new
421  * thread's PCB to get it to go back to the fork_return(), which
422  * finalizes the thread state and handles peculiarities of the first
423  * return to userspace for the new thread.
424  */
425 void
426 cpu_copy_thread(struct thread *td, struct thread *td0)
427 {
428 	struct pcb *pcb2;
429 
430 	/* Point the pcb to the top of the stack. */
431 	pcb2 = td->td_pcb;
432 
433 	/*
434 	 * Copy the upcall pcb.  This loads kernel regs.
435 	 * Those not loaded individually below get their default
436 	 * values here.
437 	 */
438 	bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
439 	pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE |
440 	    PCB_KERNNPX);
441 	pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
442 	bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save,
443 	    cpu_max_ext_state_size);
444 
445 	/*
446 	 * Create a new fresh stack for the new thread.
447 	 */
448 	bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
449 
450 	/* If the current thread has the trap bit set (i.e. a debugger had
451 	 * single stepped the process to the system call), we need to clear
452 	 * the trap flag from the new frame. Otherwise, the new thread will
453 	 * receive a (likely unexpected) SIGTRAP when it executes the first
454 	 * instruction after returning to userland.
455 	 */
456 	td->td_frame->tf_eflags &= ~PSL_T;
457 
458 	/*
459 	 * Set registers for trampoline to user mode.  Leave space for the
460 	 * return address on stack.  These are the kernel mode register values.
461 	 */
462 	pcb2->pcb_edi = 0;
463 	pcb2->pcb_esi = (int)fork_return;		    /* trampoline arg */
464 	pcb2->pcb_ebp = 0;
465 	pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
466 	pcb2->pcb_ebx = (int)td;			    /* trampoline arg */
467 	pcb2->pcb_eip = (int)fork_trampoline + setidt_disp;
468 	pcb2->pcb_gs = rgs();
469 	/*
470 	 * If we didn't copy the pcb, we'd need to do the following registers:
471 	 * pcb2->pcb_cr3:	cloned above.
472 	 * pcb2->pcb_dr*:	cloned above.
473 	 * pcb2->pcb_savefpu:	cloned above.
474 	 * pcb2->pcb_flags:	cloned above.
475 	 * pcb2->pcb_onfault:	cloned above (always NULL here?).
476 	 * pcb2->pcb_gs:	cloned above.
477 	 * pcb2->pcb_ext:	cleared below.
478 	 */
479 	pcb2->pcb_ext = NULL;
480 
481 	/* Setup to release spin count in fork_exit(). */
482 	td->td_md.md_spinlock_count = 1;
483 	td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
484 }
485 
486 /*
487  * Set that machine state for performing an upcall that starts
488  * the entry function with the given argument.
489  */
490 void
491 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg,
492     stack_t *stack)
493 {
494 
495 	/*
496 	 * Do any extra cleaning that needs to be done.
497 	 * The thread may have optional components
498 	 * that are not present in a fresh thread.
499 	 * This may be a recycled thread so make it look
500 	 * as though it's newly allocated.
501 	 */
502 	cpu_thread_clean(td);
503 
504 	/*
505 	 * Set the trap frame to point at the beginning of the entry
506 	 * function.
507 	 */
508 	td->td_frame->tf_ebp = 0;
509 	td->td_frame->tf_esp =
510 	    (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
511 	td->td_frame->tf_eip = (int)entry;
512 
513 	/* Return address sentinel value to stop stack unwinding. */
514 	suword((void *)td->td_frame->tf_esp, 0);
515 
516 	/* Pass the argument to the entry point. */
517 	suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
518 	    (int)arg);
519 }
520 
521 int
522 cpu_set_user_tls(struct thread *td, void *tls_base)
523 {
524 	struct segment_descriptor sd;
525 	uint32_t base;
526 
527 	/*
528 	 * Construct a descriptor and store it in the pcb for
529 	 * the next context switch.  Also store it in the gdt
530 	 * so that the load of tf_fs into %fs will activate it
531 	 * at return to userland.
532 	 */
533 	base = (uint32_t)tls_base;
534 	sd.sd_lobase = base & 0xffffff;
535 	sd.sd_hibase = (base >> 24) & 0xff;
536 	sd.sd_lolimit = 0xffff;	/* 4GB limit, wraps around */
537 	sd.sd_hilimit = 0xf;
538 	sd.sd_type  = SDT_MEMRWA;
539 	sd.sd_dpl   = SEL_UPL;
540 	sd.sd_p     = 1;
541 	sd.sd_xx    = 0;
542 	sd.sd_def32 = 1;
543 	sd.sd_gran  = 1;
544 	critical_enter();
545 	/* set %gs */
546 	td->td_pcb->pcb_gsd = sd;
547 	if (td == curthread) {
548 		PCPU_GET(fsgs_gdt)[1] = sd;
549 		load_gs(GSEL(GUGS_SEL, SEL_UPL));
550 	}
551 	critical_exit();
552 	return (0);
553 }
554 
555 /*
556  * Convert kernel VA to physical address
557  */
558 vm_paddr_t
559 kvtop(void *addr)
560 {
561 	vm_paddr_t pa;
562 
563 	pa = pmap_kextract((vm_offset_t)addr);
564 	if (pa == 0)
565 		panic("kvtop: zero page frame");
566 	return (pa);
567 }
568 
569 /*
570  * Get an sf_buf from the freelist.  May block if none are available.
571  */
572 void
573 sf_buf_map(struct sf_buf *sf, int flags)
574 {
575 	pt_entry_t opte, *ptep;
576 
577 	/*
578 	 * Update the sf_buf's virtual-to-physical mapping, flushing the
579 	 * virtual address from the TLB.  Since the reference count for
580 	 * the sf_buf's old mapping was zero, that mapping is not
581 	 * currently in use.  Consequently, there is no need to exchange
582 	 * the old and new PTEs atomically, even under PAE.
583 	 */
584 	ptep = vtopte(sf->kva);
585 	opte = *ptep;
586 	*ptep = VM_PAGE_TO_PHYS(sf->m) | PG_RW | PG_V |
587 	    pmap_cache_bits(kernel_pmap, sf->m->md.pat_mode, 0);
588 
589 	/*
590 	 * Avoid unnecessary TLB invalidations: If the sf_buf's old
591 	 * virtual-to-physical mapping was not used, then any processor
592 	 * that has invalidated the sf_buf's virtual address from its TLB
593 	 * since the last used mapping need not invalidate again.
594 	 */
595 #ifdef SMP
596 	if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
597 		CPU_ZERO(&sf->cpumask);
598 
599 	sf_buf_shootdown(sf, flags);
600 #else
601 	if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
602 		pmap_invalidate_page(kernel_pmap, sf->kva);
603 #endif
604 }
605 
606 #ifdef SMP
607 void
608 sf_buf_shootdown(struct sf_buf *sf, int flags)
609 {
610 	cpuset_t other_cpus;
611 	u_int cpuid;
612 
613 	sched_pin();
614 	cpuid = PCPU_GET(cpuid);
615 	if (!CPU_ISSET(cpuid, &sf->cpumask)) {
616 		CPU_SET(cpuid, &sf->cpumask);
617 		invlpg(sf->kva);
618 	}
619 	if ((flags & SFB_CPUPRIVATE) == 0) {
620 		other_cpus = all_cpus;
621 		CPU_CLR(cpuid, &other_cpus);
622 		CPU_NAND(&other_cpus, &sf->cpumask);
623 		if (!CPU_EMPTY(&other_cpus)) {
624 			CPU_OR(&sf->cpumask, &other_cpus);
625 			smp_masked_invlpg(other_cpus, sf->kva, kernel_pmap);
626 		}
627 	}
628 	sched_unpin();
629 }
630 #endif
631 
632 /*
633  * MD part of sf_buf_free().
634  */
635 int
636 sf_buf_unmap(struct sf_buf *sf)
637 {
638 
639 	return (0);
640 }
641 
642 static void
643 sf_buf_invalidate(struct sf_buf *sf)
644 {
645 	vm_page_t m = sf->m;
646 
647 	/*
648 	 * Use pmap_qenter to update the pte for
649 	 * existing mapping, in particular, the PAT
650 	 * settings are recalculated.
651 	 */
652 	pmap_qenter(sf->kva, &m, 1);
653 	pmap_invalidate_cache_range(sf->kva, sf->kva + PAGE_SIZE);
654 }
655 
656 /*
657  * Invalidate the cache lines that may belong to the page, if
658  * (possibly old) mapping of the page by sf buffer exists.  Returns
659  * TRUE when mapping was found and cache invalidated.
660  */
661 boolean_t
662 sf_buf_invalidate_cache(vm_page_t m)
663 {
664 
665 	return (sf_buf_process_page(m, sf_buf_invalidate));
666 }
667 
668 /*
669  * Software interrupt handler for queued VM system processing.
670  */
671 void
672 swi_vm(void *dummy)
673 {
674 	if (busdma_swi_pending != 0)
675 		busdma_swi();
676 }
677 
678 /*
679  * Tell whether this address is in some physical memory region.
680  * Currently used by the kernel coredump code in order to avoid
681  * dumping the ``ISA memory hole'' which could cause indefinite hangs,
682  * or other unpredictable behaviour.
683  */
684 
685 int
686 is_physical_memory(vm_paddr_t addr)
687 {
688 
689 #ifdef DEV_ISA
690 	/* The ISA ``memory hole''. */
691 	if (addr >= 0xa0000 && addr < 0x100000)
692 		return 0;
693 #endif
694 
695 	/*
696 	 * stuff other tests for known memory-mapped devices (PCI?)
697 	 * here
698 	 */
699 
700 	return 1;
701 }
702