2 * Copyright (c) 1982, 1986 The Regents of the University of California.
3 * Copyright (c) 1989, 1990 William Jolitz
4 * Copyright (c) 1994 John Dyson
7 * This code is derived from software contributed to Berkeley by
8 * the Systems Programming Group of the University of Utah Computer
9 * Science Department, and William Jolitz.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
40 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
48 #include "opt_reset.h"
52 #include <sys/param.h>
53 #include <sys/systm.h>
56 #include <sys/kernel.h>
59 #include <sys/malloc.h>
61 #include <sys/mutex.h>
62 #include <sys/pioctl.h>
64 #include <sys/sysent.h>
65 #include <sys/sf_buf.h>
67 #include <sys/sched.h>
68 #include <sys/sysctl.h>
69 #include <sys/unistd.h>
70 #include <sys/vnode.h>
71 #include <sys/vmmeter.h>
73 #include <machine/cpu.h>
74 #include <machine/cputypes.h>
75 #include <machine/md_var.h>
76 #include <machine/pcb.h>
77 #include <machine/pcb_ext.h>
78 #include <machine/smp.h>
79 #include <machine/vm86.h>
82 #include <machine/elan_mmcr.h>
86 #include <vm/vm_extern.h>
87 #include <vm/vm_kern.h>
88 #include <vm/vm_page.h>
89 #include <vm/vm_map.h>
90 #include <vm/vm_param.h>
93 #include <xen/hypervisor.h>
96 #include <pc98/cbus/cbus.h>
98 #include <x86/isa/isa.h>
102 #include <machine/xbox.h>
106 #define NSFBUFS (512 + maxusers * 16)
109 _Static_assert(OFFSETOF_CURTHREAD == offsetof(struct pcpu, pc_curthread),
110 "OFFSETOF_CURTHREAD does not correspond with offset of pc_curthread.");
111 _Static_assert(OFFSETOF_CURPCB == offsetof(struct pcpu, pc_curpcb),
112 "OFFSETOF_CURPCB does not correspond with offset of pc_curpcb.");
114 static void cpu_reset_real(void);
116 static void cpu_reset_proxy(void);
117 static u_int cpu_reset_proxyid;
118 static volatile u_int cpu_reset_proxy_active;
122 static int nsfbufspeak;
123 static int nsfbufsused;
125 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RDTUN, &nsfbufs, 0,
126 "Maximum number of sendfile(2) sf_bufs available");
127 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufspeak, CTLFLAG_RD, &nsfbufspeak, 0,
128 "Number of sendfile(2) sf_bufs at peak usage");
129 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufsused, CTLFLAG_RD, &nsfbufsused, 0,
130 "Number of sendfile(2) sf_bufs in use");
132 static void sf_buf_init(void *arg);
133 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
135 LIST_HEAD(sf_head, sf_buf);
138 * A hash table of active sendfile(2) buffers
140 static struct sf_head *sf_buf_active;
141 static u_long sf_buf_hashmask;
143 #define SF_BUF_HASH(m) (((m) - vm_page_array) & sf_buf_hashmask)
145 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
146 static u_int sf_buf_alloc_want;
149 * A lock used to synchronize access to the hash table and free list
151 static struct mtx sf_buf_lock;
153 extern int _ucodesel, _udatasel;
156 * Finish a fork operation, with process p2 nearly set up.
157 * Copy and update the pcb, set up the stack so that the child
158 * ready to run and return to user mode.
161 cpu_fork(td1, p2, td2, flags)
162 register struct thread *td1;
163 register struct proc *p2;
167 register struct proc *p1;
172 if ((flags & RFPROC) == 0) {
173 if ((flags & RFMEM) == 0) {
174 /* unshare user LDT */
175 struct mdproc *mdp1 = &p1->p_md;
176 struct proc_ldt *pldt, *pldt1;
178 mtx_lock_spin(&dt_lock);
179 if ((pldt1 = mdp1->md_ldt) != NULL &&
180 pldt1->ldt_refcnt > 1) {
181 pldt = user_ldt_alloc(mdp1, pldt1->ldt_len);
183 panic("could not copy LDT");
186 user_ldt_deref(pldt1);
188 mtx_unlock_spin(&dt_lock);
193 /* Ensure that td1's pcb is up to date. */
194 if (td1 == curthread)
195 td1->td_pcb->pcb_gs = rgs();
198 if (PCPU_GET(fpcurthread) == td1)
199 npxsave(td1->td_pcb->pcb_save);
203 /* Point the pcb to the top of the stack */
204 pcb2 = (struct pcb *)(td2->td_kstack +
205 td2->td_kstack_pages * PAGE_SIZE) - 1;
209 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
211 /* Properly initialize pcb_save */
212 pcb2->pcb_save = &pcb2->pcb_user_save;
214 /* Point mdproc and then copy over td1's contents */
216 bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
219 * Create a new fresh stack for the new process.
220 * Copy the trap frame for the return to user mode as if from a
221 * syscall. This copies most of the user mode register values.
222 * The -16 is so we can expand the trapframe if we go to vm86.
224 td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
225 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
227 td2->td_frame->tf_eax = 0; /* Child returns zero */
228 td2->td_frame->tf_eflags &= ~PSL_C; /* success */
229 td2->td_frame->tf_edx = 1;
232 * If the parent process has the trap bit set (i.e. a debugger had
233 * single stepped the process to the system call), we need to clear
234 * the trap flag from the new frame unless the debugger had set PF_FORK
235 * on the parent. Otherwise, the child will receive a (likely
236 * unexpected) SIGTRAP when it executes the first instruction after
237 * returning to userland.
239 if ((p1->p_pfsflags & PF_FORK) == 0)
240 td2->td_frame->tf_eflags &= ~PSL_T;
243 * Set registers for trampoline to user mode. Leave space for the
244 * return address on stack. These are the kernel mode register values.
247 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
249 pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
252 pcb2->pcb_esi = (int)fork_return; /* fork_trampoline argument */
254 pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
255 pcb2->pcb_ebx = (int)td2; /* fork_trampoline argument */
256 pcb2->pcb_eip = (int)fork_trampoline;
257 pcb2->pcb_psl = PSL_KERNEL; /* ints disabled */
259 * pcb2->pcb_dr*: cloned above.
260 * pcb2->pcb_savefpu: cloned above.
261 * pcb2->pcb_flags: cloned above.
262 * pcb2->pcb_onfault: cloned above (always NULL here?).
263 * pcb2->pcb_gs: cloned above.
264 * pcb2->pcb_ext: cleared below.
268 * XXX don't copy the i/o pages. this should probably be fixed.
272 /* Copy the LDT, if necessary. */
273 mtx_lock_spin(&dt_lock);
274 if (mdp2->md_ldt != NULL) {
276 mdp2->md_ldt->ldt_refcnt++;
278 mdp2->md_ldt = user_ldt_alloc(mdp2,
279 mdp2->md_ldt->ldt_len);
280 if (mdp2->md_ldt == NULL)
281 panic("could not copy LDT");
284 mtx_unlock_spin(&dt_lock);
286 /* Setup to release spin count in fork_exit(). */
287 td2->td_md.md_spinlock_count = 1;
289 * XXX XEN need to check on PSL_USER is handled
291 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
293 * Now, cpu_switch() can schedule the new process.
294 * pcb_esp is loaded pointing to the cpu_switch() stack frame
295 * containing the return address when exiting cpu_switch.
296 * This will normally be to fork_trampoline(), which will have
297 * %ebx loaded with the new proc's pointer. fork_trampoline()
298 * will set up a stack to call fork_return(p, frame); to complete
299 * the return to user-mode.
304 * Intercept the return address from a freshly forked process that has NOT
305 * been scheduled yet.
307 * This is needed to make kernel threads stay in kernel mode.
310 cpu_set_fork_handler(td, func, arg)
312 void (*func)(void *);
316 * Note that the trap frame follows the args, so the function
317 * is really called like this: func(arg, frame);
319 td->td_pcb->pcb_esi = (int) func; /* function */
320 td->td_pcb->pcb_ebx = (int) arg; /* first arg */
324 cpu_exit(struct thread *td)
328 * If this process has a custom LDT, release it. Reset pc->pcb_gs
329 * and %gs before we free it in case they refer to an LDT entry.
331 mtx_lock_spin(&dt_lock);
332 if (td->td_proc->p_md.md_ldt) {
333 td->td_pcb->pcb_gs = _udatasel;
337 mtx_unlock_spin(&dt_lock);
341 cpu_thread_exit(struct thread *td)
346 if (td == PCPU_GET(fpcurthread))
351 /* Disable any hardware breakpoints. */
352 if (td->td_pcb->pcb_flags & PCB_DBREGS) {
354 td->td_pcb->pcb_flags &= ~PCB_DBREGS;
359 cpu_thread_clean(struct thread *td)
364 if (pcb->pcb_ext != NULL) {
365 /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
367 * XXX do we need to move the TSS off the allocated pages
368 * before freeing them? (not done here)
370 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_ext,
377 cpu_thread_swapin(struct thread *td)
382 cpu_thread_swapout(struct thread *td)
387 cpu_thread_alloc(struct thread *td)
390 td->td_pcb = (struct pcb *)(td->td_kstack +
391 td->td_kstack_pages * PAGE_SIZE) - 1;
392 td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1;
393 td->td_pcb->pcb_ext = NULL;
394 td->td_pcb->pcb_save = &td->td_pcb->pcb_user_save;
398 cpu_thread_free(struct thread *td)
401 cpu_thread_clean(td);
405 cpu_set_syscall_retval(struct thread *td, int error)
410 td->td_frame->tf_eax = td->td_retval[0];
411 td->td_frame->tf_edx = td->td_retval[1];
412 td->td_frame->tf_eflags &= ~PSL_C;
417 * Reconstruct pc, assuming lcall $X,y is 7 bytes, int
418 * 0x80 is 2 bytes. We saved this in tf_err.
420 td->td_frame->tf_eip -= td->td_frame->tf_err;
427 if (td->td_proc->p_sysent->sv_errsize) {
428 if (error >= td->td_proc->p_sysent->sv_errsize)
429 error = -1; /* XXX */
431 error = td->td_proc->p_sysent->sv_errtbl[error];
433 td->td_frame->tf_eax = error;
434 td->td_frame->tf_eflags |= PSL_C;
440 * Initialize machine state (pcb and trap frame) for a new thread about to
441 * upcall. Put enough state in the new thread's PCB to get it to go back
442 * userret(), where we can intercept it again to set the return (upcall)
443 * Address and stack, along with those from upcals that are from other sources
444 * such as those generated in thread_userret() itself.
447 cpu_set_upcall(struct thread *td, struct thread *td0)
451 /* Point the pcb to the top of the stack. */
455 * Copy the upcall pcb. This loads kernel regs.
456 * Those not loaded individually below get their default
459 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
460 pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE);
461 pcb2->pcb_save = &pcb2->pcb_user_save;
464 * Create a new fresh stack for the new thread.
466 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
468 /* If the current thread has the trap bit set (i.e. a debugger had
469 * single stepped the process to the system call), we need to clear
470 * the trap flag from the new frame. Otherwise, the new thread will
471 * receive a (likely unexpected) SIGTRAP when it executes the first
472 * instruction after returning to userland.
474 td->td_frame->tf_eflags &= ~PSL_T;
477 * Set registers for trampoline to user mode. Leave space for the
478 * return address on stack. These are the kernel mode register values.
481 pcb2->pcb_esi = (int)fork_return; /* trampoline arg */
483 pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
484 pcb2->pcb_ebx = (int)td; /* trampoline arg */
485 pcb2->pcb_eip = (int)fork_trampoline;
486 pcb2->pcb_psl &= ~(PSL_I); /* interrupts must be disabled */
487 pcb2->pcb_gs = rgs();
489 * If we didn't copy the pcb, we'd need to do the following registers:
490 * pcb2->pcb_cr3: cloned above.
491 * pcb2->pcb_dr*: cloned above.
492 * pcb2->pcb_savefpu: cloned above.
493 * pcb2->pcb_flags: cloned above.
494 * pcb2->pcb_onfault: cloned above (always NULL here?).
495 * pcb2->pcb_gs: cloned above.
496 * pcb2->pcb_ext: cleared below.
498 pcb2->pcb_ext = NULL;
500 /* Setup to release spin count in fork_exit(). */
501 td->td_md.md_spinlock_count = 1;
502 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
506 * Set that machine state for performing an upcall that has to
507 * be done in thread_userret() so that those upcalls generated
508 * in thread_userret() itself can be done as well.
511 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
516 * Do any extra cleaning that needs to be done.
517 * The thread may have optional components
518 * that are not present in a fresh thread.
519 * This may be a recycled thread so make it look
520 * as though it's newly allocated.
522 cpu_thread_clean(td);
525 * Set the trap frame to point at the beginning of the uts
528 td->td_frame->tf_ebp = 0;
529 td->td_frame->tf_esp =
530 (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
531 td->td_frame->tf_eip = (int)entry;
534 * Pass the address of the mailbox for this kse to the uts
535 * function as a parameter on the stack.
537 suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
542 cpu_set_user_tls(struct thread *td, void *tls_base)
544 struct segment_descriptor sd;
548 * Construct a descriptor and store it in the pcb for
549 * the next context switch. Also store it in the gdt
550 * so that the load of tf_fs into %fs will activate it
551 * at return to userland.
553 base = (uint32_t)tls_base;
554 sd.sd_lobase = base & 0xffffff;
555 sd.sd_hibase = (base >> 24) & 0xff;
556 sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */
558 sd.sd_type = SDT_MEMRWA;
566 td->td_pcb->pcb_gsd = sd;
567 if (td == curthread) {
568 PCPU_GET(fsgs_gdt)[1] = sd;
569 load_gs(GSEL(GUGS_SEL, SEL_UPL));
576 * Convert kernel VA to physical address
583 pa = pmap_kextract((vm_offset_t)addr);
585 panic("kvtop: zero page frame");
595 cpu_reset_proxy_active = 1;
596 while (cpu_reset_proxy_active == 1)
597 ; /* Wait for other cpu to see that we've started */
598 CPU_SETOF(cpu_reset_proxyid, &tcrp);
600 printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
610 if (arch_i386_is_xbox) {
611 /* Kick the PIC16L, it can reboot the box */
623 CPU_CLR(PCPU_GET(cpuid), &map);
624 CPU_NAND(&map, &stopped_cpus);
625 if (!CPU_EMPTY(&map)) {
626 printf("cpu_reset: Stopping other CPUs\n");
630 if (PCPU_GET(cpuid) != 0) {
631 cpu_reset_proxyid = PCPU_GET(cpuid);
632 cpustop_restartfunc = cpu_reset_proxy;
633 cpu_reset_proxy_active = 0;
634 printf("cpu_reset: Restarting BSP\n");
636 /* Restart CPU #0. */
637 /* XXX: restart_cpus(1 << 0); */
638 CPU_SETOF(0, &started_cpus);
642 while (cpu_reset_proxy_active == 0 && cnt < 10000000)
643 cnt++; /* Wait for BSP to announce restart */
644 if (cpu_reset_proxy_active == 0)
645 printf("cpu_reset: Failed to restart BSP\n");
647 cpu_reset_proxy_active = 2;
663 struct region_descriptor null_idt;
670 if (smp_processor_id() == 0)
671 HYPERVISOR_shutdown(SHUTDOWN_reboot);
673 HYPERVISOR_shutdown(SHUTDOWN_poweroff);
676 if (elan_mmcr != NULL)
677 elan_mmcr->RESCFG = 1;
680 if (cpu == CPU_GEODE1100) {
681 /* Attempt Geode's own reset */
682 outl(0xcf8, 0x80009044ul);
688 * Attempt to do a CPU reset via CPU reset port.
690 if ((inb(0x35) & 0xa0) != 0xa0) {
691 outb(0x37, 0x0f); /* SHUT0 = 0. */
692 outb(0x37, 0x0b); /* SHUT1 = 0. */
694 outb(0xf0, 0x00); /* Reset. */
696 #if !defined(BROKEN_KEYBOARD_RESET)
698 * Attempt to do a CPU reset via the keyboard controller,
699 * do not turn off GateA20, as any machine that fails
700 * to do the reset here would then end up in no man's land.
702 outb(IO_KBD + 4, 0xFE);
703 DELAY(500000); /* wait 0.5 sec to see if that did it */
707 * Attempt to force a reset via the Reset Control register at
708 * I/O port 0xcf9. Bit 2 forces a system reset when it
709 * transitions from 0 to 1. Bit 1 selects the type of reset
710 * to attempt: 0 selects a "soft" reset, and 1 selects a
711 * "hard" reset. We try a "hard" reset. The first write sets
712 * bit 1 to select a "hard" reset and clears bit 2. The
713 * second write forces a 0 -> 1 transition in bit 2 to trigger
718 DELAY(500000); /* wait 0.5 sec to see if that did it */
721 * Attempt to force a reset via the Fast A20 and Init register
722 * at I/O port 0x92. Bit 1 serves as an alternate A20 gate.
723 * Bit 0 asserts INIT# when set to 1. We are careful to only
724 * preserve bit 1 while setting bit 0. We also must clear bit
725 * 0 before setting it if it isn't already clear.
730 outb(0x92, b & 0xfe);
732 DELAY(500000); /* wait 0.5 sec to see if that did it */
736 printf("No known reset method worked, attempting CPU shutdown\n");
737 DELAY(1000000); /* wait 1 sec for printf to complete */
740 null_idt.rd_limit = 0;
741 null_idt.rd_base = 0;
744 /* "good night, sweet prince .... <THUNK!>" */
752 * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
755 sf_buf_init(void *arg)
757 struct sf_buf *sf_bufs;
762 TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
764 sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
765 TAILQ_INIT(&sf_buf_freelist);
766 sf_base = kva_alloc(nsfbufs * PAGE_SIZE);
767 sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
769 for (i = 0; i < nsfbufs; i++) {
770 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
771 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
773 sf_buf_alloc_want = 0;
774 mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
778 * Invalidate the cache lines that may belong to the page, if
779 * (possibly old) mapping of the page by sf buffer exists. Returns
780 * TRUE when mapping was found and cache invalidated.
783 sf_buf_invalidate_cache(vm_page_t m)
785 struct sf_head *hash_list;
789 hash_list = &sf_buf_active[SF_BUF_HASH(m)];
791 mtx_lock(&sf_buf_lock);
792 LIST_FOREACH(sf, hash_list, list_entry) {
795 * Use pmap_qenter to update the pte for
796 * existing mapping, in particular, the PAT
797 * settings are recalculated.
799 pmap_qenter(sf->kva, &m, 1);
800 pmap_invalidate_cache_range(sf->kva, sf->kva +
806 mtx_unlock(&sf_buf_lock);
811 * Get an sf_buf from the freelist. May block if none are available.
814 sf_buf_alloc(struct vm_page *m, int flags)
816 pt_entry_t opte, *ptep;
817 struct sf_head *hash_list;
825 KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
826 ("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
827 hash_list = &sf_buf_active[SF_BUF_HASH(m)];
828 mtx_lock(&sf_buf_lock);
829 LIST_FOREACH(sf, hash_list, list_entry) {
832 if (sf->ref_count == 1) {
833 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
835 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
844 while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
845 if (flags & SFB_NOWAIT)
848 SFSTAT_INC(sf_allocwait);
849 error = msleep(&sf_buf_freelist, &sf_buf_lock,
850 (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
854 * If we got a signal, don't risk going back to sleep.
859 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
861 LIST_REMOVE(sf, list_entry);
862 LIST_INSERT_HEAD(hash_list, sf, list_entry);
866 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
869 * Update the sf_buf's virtual-to-physical mapping, flushing the
870 * virtual address from the TLB. Since the reference count for
871 * the sf_buf's old mapping was zero, that mapping is not
872 * currently in use. Consequently, there is no need to exchange
873 * the old and new PTEs atomically, even under PAE.
875 ptep = vtopte(sf->kva);
878 PT_SET_MA(sf->kva, xpmap_ptom(VM_PAGE_TO_PHYS(m)) | pgeflag
879 | PG_RW | PG_V | pmap_cache_bits(m->md.pat_mode, 0));
881 *ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V |
882 pmap_cache_bits(m->md.pat_mode, 0);
886 * Avoid unnecessary TLB invalidations: If the sf_buf's old
887 * virtual-to-physical mapping was not used, then any processor
888 * that has invalidated the sf_buf's virtual address from its TLB
889 * since the last used mapping need not invalidate again.
892 if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
893 CPU_ZERO(&sf->cpumask);
896 cpuid = PCPU_GET(cpuid);
897 if (!CPU_ISSET(cpuid, &sf->cpumask)) {
898 CPU_SET(cpuid, &sf->cpumask);
901 if ((flags & SFB_CPUPRIVATE) == 0) {
902 other_cpus = all_cpus;
903 CPU_CLR(cpuid, &other_cpus);
904 CPU_NAND(&other_cpus, &sf->cpumask);
905 if (!CPU_EMPTY(&other_cpus)) {
906 CPU_OR(&sf->cpumask, &other_cpus);
907 smp_masked_invlpg(other_cpus, sf->kva);
912 if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
913 pmap_invalidate_page(kernel_pmap, sf->kva);
916 mtx_unlock(&sf_buf_lock);
921 * Remove a reference from the given sf_buf, adding it to the free
922 * list when its reference count reaches zero. A freed sf_buf still,
923 * however, retains its virtual-to-physical mapping until it is
924 * recycled or reactivated by sf_buf_alloc(9).
927 sf_buf_free(struct sf_buf *sf)
930 mtx_lock(&sf_buf_lock);
932 if (sf->ref_count == 0) {
933 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
937 * Xen doesn't like having dangling R/W mappings
939 pmap_qremove(sf->kva, 1);
941 LIST_REMOVE(sf, list_entry);
943 if (sf_buf_alloc_want > 0)
944 wakeup(&sf_buf_freelist);
946 mtx_unlock(&sf_buf_lock);
950 * Software interrupt handler for queued VM system processing.
955 if (busdma_swi_pending != 0)
960 * Tell whether this address is in some physical memory region.
961 * Currently used by the kernel coredump code in order to avoid
962 * dumping the ``ISA memory hole'' which could cause indefinite hangs,
963 * or other unpredictable behaviour.
967 is_physical_memory(vm_paddr_t addr)
971 /* The ISA ``memory hole''. */
972 if (addr >= 0xa0000 && addr < 0x100000)
977 * stuff other tests for known memory-mapped devices (PCI?)