The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/vm_machdep.c

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    1 /*-
    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
    5  * All rights reserved.
    6  *
    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.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   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.
   26  *
   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
   37  * SUCH DAMAGE.
   38  *
   39  *      from: @(#)vm_machdep.c  7.3 (Berkeley) 5/13/91
   40  *      Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
   41  */
   42 
   43 #include <sys/cdefs.h>
   44 __FBSDID("$FreeBSD: releng/7.3/sys/i386/i386/vm_machdep.c 203047 2010-01-26 20:58:09Z jhb $");
   45 
   46 #include "opt_isa.h"
   47 #include "opt_npx.h"
   48 #include "opt_reset.h"
   49 #include "opt_cpu.h"
   50 #include "opt_xbox.h"
   51 
   52 #include <sys/param.h>
   53 #include <sys/systm.h>
   54 #include <sys/bio.h>
   55 #include <sys/buf.h>
   56 #include <sys/kse.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/sf_buf.h>
   66 #include <sys/smp.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>
   72 
   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>
   80 
   81 #ifdef CPU_ELAN
   82 #include <machine/elan_mmcr.h>
   83 #endif
   84 
   85 #include <vm/vm.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>
   91 
   92 #ifdef PC98
   93 #include <pc98/cbus/cbus.h>
   94 #else
   95 #include <i386/isa/isa.h>
   96 #endif
   97 
   98 #ifdef XBOX
   99 #include <machine/xbox.h>
  100 #endif
  101 
  102 #ifndef NSFBUFS
  103 #define NSFBUFS         (512 + maxusers * 16)
  104 #endif
  105 
  106 static void     cpu_reset_real(void);
  107 #ifdef SMP
  108 static void     cpu_reset_proxy(void);
  109 static u_int    cpu_reset_proxyid;
  110 static volatile u_int   cpu_reset_proxy_active;
  111 #endif
  112 static void     sf_buf_init(void *arg);
  113 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
  114 
  115 LIST_HEAD(sf_head, sf_buf);
  116 
  117 /*
  118  * A hash table of active sendfile(2) buffers
  119  */
  120 static struct sf_head *sf_buf_active;
  121 static u_long sf_buf_hashmask;
  122 
  123 #define SF_BUF_HASH(m)  (((m) - vm_page_array) & sf_buf_hashmask)
  124 
  125 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
  126 static u_int    sf_buf_alloc_want;
  127 
  128 /*
  129  * A lock used to synchronize access to the hash table and free list
  130  */
  131 static struct mtx sf_buf_lock;
  132 
  133 extern int      _ucodesel, _udatasel;
  134 
  135 /*
  136  * Finish a fork operation, with process p2 nearly set up.
  137  * Copy and update the pcb, set up the stack so that the child
  138  * ready to run and return to user mode.
  139  */
  140 void
  141 cpu_fork(td1, p2, td2, flags)
  142         register struct thread *td1;
  143         register struct proc *p2;
  144         struct thread *td2;
  145         int flags;
  146 {
  147         register struct proc *p1;
  148         struct pcb *pcb2;
  149         struct mdproc *mdp2;
  150 #ifdef DEV_NPX
  151         register_t savecrit;
  152 #endif
  153 
  154         p1 = td1->td_proc;
  155         if ((flags & RFPROC) == 0) {
  156                 if ((flags & RFMEM) == 0) {
  157                         /* unshare user LDT */
  158                         struct mdproc *mdp1 = &p1->p_md;
  159                         struct proc_ldt *pldt, *pldt1;
  160 
  161                         mtx_lock_spin(&dt_lock);
  162                         if ((pldt1 = mdp1->md_ldt) != NULL &&
  163                             pldt1->ldt_refcnt > 1) {
  164                                 pldt = user_ldt_alloc(mdp1, pldt1->ldt_len);
  165                                 if (pldt == NULL)
  166                                         panic("could not copy LDT");
  167                                 mdp1->md_ldt = pldt;
  168                                 set_user_ldt(mdp1);
  169                                 user_ldt_deref(pldt1);
  170                         } else
  171                                 mtx_unlock_spin(&dt_lock);
  172                 }
  173                 return;
  174         }
  175 
  176         /* Ensure that p1's pcb is up to date. */
  177         if (td1 == curthread)
  178                 td1->td_pcb->pcb_gs = rgs();
  179 #ifdef DEV_NPX
  180         savecrit = intr_disable();
  181         if (PCPU_GET(fpcurthread) == td1)
  182                 npxsave(&td1->td_pcb->pcb_save);
  183         intr_restore(savecrit);
  184 #endif
  185 
  186         /* Point the pcb to the top of the stack */
  187         pcb2 = (struct pcb *)(td2->td_kstack +
  188             td2->td_kstack_pages * PAGE_SIZE) - 1;
  189         td2->td_pcb = pcb2;
  190 
  191         /* Copy p1's pcb */
  192         bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
  193 
  194         /* Point mdproc and then copy over td1's contents */
  195         mdp2 = &p2->p_md;
  196         bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
  197 
  198         /*
  199          * Create a new fresh stack for the new process.
  200          * Copy the trap frame for the return to user mode as if from a
  201          * syscall.  This copies most of the user mode register values.
  202          * The -16 is so we can expand the trapframe if we go to vm86.
  203          */
  204         td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
  205         bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
  206 
  207         td2->td_frame->tf_eax = 0;              /* Child returns zero */
  208         td2->td_frame->tf_eflags &= ~PSL_C;     /* success */
  209         td2->td_frame->tf_edx = 1;
  210 
  211         /*
  212          * If the parent process has the trap bit set (i.e. a debugger had
  213          * single stepped the process to the system call), we need to clear
  214          * the trap flag from the new frame unless the debugger had set PF_FORK
  215          * on the parent.  Otherwise, the child will receive a (likely
  216          * unexpected) SIGTRAP when it executes the first instruction after
  217          * returning  to userland.
  218          */
  219         if ((p1->p_pfsflags & PF_FORK) == 0)
  220                 td2->td_frame->tf_eflags &= ~PSL_T;
  221 
  222         /*
  223          * Set registers for trampoline to user mode.  Leave space for the
  224          * return address on stack.  These are the kernel mode register values.
  225          */
  226 #ifdef PAE
  227         pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
  228 #else
  229         pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
  230 #endif
  231         pcb2->pcb_edi = 0;
  232         pcb2->pcb_esi = (int)fork_return;       /* fork_trampoline argument */
  233         pcb2->pcb_ebp = 0;
  234         pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
  235         pcb2->pcb_ebx = (int)td2;               /* fork_trampoline argument */
  236         pcb2->pcb_eip = (int)fork_trampoline;
  237         pcb2->pcb_psl = PSL_KERNEL;             /* ints disabled */
  238         /*-
  239          * pcb2->pcb_dr*:       cloned above.
  240          * pcb2->pcb_savefpu:   cloned above.
  241          * pcb2->pcb_flags:     cloned above.
  242          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  243          * pcb2->pcb_gs:        cloned above.
  244          * pcb2->pcb_ext:       cleared below.
  245          */
  246 
  247         /*
  248          * XXX don't copy the i/o pages.  this should probably be fixed.
  249          */
  250         pcb2->pcb_ext = 0;
  251 
  252         /* Copy the LDT, if necessary. */
  253         mtx_lock_spin(&dt_lock);
  254         if (mdp2->md_ldt != NULL) {
  255                 if (flags & RFMEM) {
  256                         mdp2->md_ldt->ldt_refcnt++;
  257                 } else {
  258                         mdp2->md_ldt = user_ldt_alloc(mdp2,
  259                             mdp2->md_ldt->ldt_len);
  260                         if (mdp2->md_ldt == NULL)
  261                                 panic("could not copy LDT");
  262                 }
  263         }
  264         mtx_unlock_spin(&dt_lock);
  265 
  266         /* Setup to release spin count in fork_exit(). */
  267         td2->td_md.md_spinlock_count = 1;
  268         td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  269 
  270         /*
  271          * Now, cpu_switch() can schedule the new process.
  272          * pcb_esp is loaded pointing to the cpu_switch() stack frame
  273          * containing the return address when exiting cpu_switch.
  274          * This will normally be to fork_trampoline(), which will have
  275          * %ebx loaded with the new proc's pointer.  fork_trampoline()
  276          * will set up a stack to call fork_return(p, frame); to complete
  277          * the return to user-mode.
  278          */
  279 }
  280 
  281 /*
  282  * Intercept the return address from a freshly forked process that has NOT
  283  * been scheduled yet.
  284  *
  285  * This is needed to make kernel threads stay in kernel mode.
  286  */
  287 void
  288 cpu_set_fork_handler(td, func, arg)
  289         struct thread *td;
  290         void (*func)(void *);
  291         void *arg;
  292 {
  293         /*
  294          * Note that the trap frame follows the args, so the function
  295          * is really called like this:  func(arg, frame);
  296          */
  297         td->td_pcb->pcb_esi = (int) func;       /* function */
  298         td->td_pcb->pcb_ebx = (int) arg;        /* first arg */
  299 }
  300 
  301 void
  302 cpu_exit(struct thread *td)
  303 {
  304 
  305         /*
  306          * If this process has a custom LDT, release it.  Reset pc->pcb_gs
  307          * and %gs before we free it in case they refer to an LDT entry.
  308          */
  309         mtx_lock_spin(&dt_lock);
  310         if (td->td_proc->p_md.md_ldt) {
  311                 td->td_pcb->pcb_gs = _udatasel;
  312                 load_gs(_udatasel);
  313                 user_ldt_free(td);
  314         } else
  315                 mtx_unlock_spin(&dt_lock);
  316 }
  317 
  318 void
  319 cpu_thread_exit(struct thread *td)
  320 {
  321 
  322 #ifdef DEV_NPX
  323         if (td == PCPU_GET(fpcurthread))
  324                 npxdrop();
  325 #endif
  326 
  327         /* Disable any hardware breakpoints. */
  328         if (td->td_pcb->pcb_flags & PCB_DBREGS) {
  329                 reset_dbregs();
  330                 td->td_pcb->pcb_flags &= ~PCB_DBREGS;
  331         }
  332 }
  333 
  334 void
  335 cpu_thread_clean(struct thread *td)
  336 {
  337         struct pcb *pcb;
  338 
  339         pcb = td->td_pcb; 
  340         if (pcb->pcb_ext != NULL) {
  341                 /* XXXKSE  XXXSMP  not SMP SAFE.. what locks do we have? */
  342                 /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
  343                 /*
  344                  * XXX do we need to move the TSS off the allocated pages
  345                  * before freeing them?  (not done here)
  346                  */
  347                 kmem_free(kernel_map, (vm_offset_t)pcb->pcb_ext,
  348                     ctob(IOPAGES + 1));
  349                 pcb->pcb_ext = NULL;
  350         }
  351 }
  352 
  353 void
  354 cpu_thread_swapin(struct thread *td)
  355 {
  356 }
  357 
  358 void
  359 cpu_thread_swapout(struct thread *td)
  360 {
  361 }
  362 
  363 void
  364 cpu_thread_alloc(struct thread *td)
  365 {
  366 
  367         td->td_pcb = (struct pcb *)(td->td_kstack +
  368             td->td_kstack_pages * PAGE_SIZE) - 1;
  369         td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1;
  370         td->td_pcb->pcb_ext = NULL; 
  371 }
  372 
  373 void
  374 cpu_thread_free(struct thread *td)
  375 {
  376 
  377         cpu_thread_clean(td);
  378 }
  379 
  380 /*
  381  * Initialize machine state (pcb and trap frame) for a new thread about to
  382  * upcall. Put enough state in the new thread's PCB to get it to go back 
  383  * userret(), where we can intercept it again to set the return (upcall)
  384  * Address and stack, along with those from upcals that are from other sources
  385  * such as those generated in thread_userret() itself.
  386  */
  387 void
  388 cpu_set_upcall(struct thread *td, struct thread *td0)
  389 {
  390         struct pcb *pcb2;
  391 
  392         /* Point the pcb to the top of the stack. */
  393         pcb2 = td->td_pcb;
  394 
  395         /*
  396          * Copy the upcall pcb.  This loads kernel regs.
  397          * Those not loaded individually below get their default
  398          * values here.
  399          *
  400          * XXXKSE It might be a good idea to simply skip this as
  401          * the values of the other registers may be unimportant.
  402          * This would remove any requirement for knowing the KSE
  403          * at this time (see the matching comment below for
  404          * more analysis) (need a good safe default).
  405          */
  406         bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
  407         pcb2->pcb_flags &= ~(PCB_NPXTRAP|PCB_NPXINITDONE);
  408 
  409         /*
  410          * Create a new fresh stack for the new thread.
  411          * The -16 is so we can expand the trapframe if we go to vm86.
  412          * Don't forget to set this stack value into whatever supplies
  413          * the address for the fault handlers.
  414          * The contexts are filled in at the time we actually DO the
  415          * upcall as only then do we know which KSE we got.
  416          */
  417         bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
  418 
  419         /*
  420          * Set registers for trampoline to user mode.  Leave space for the
  421          * return address on stack.  These are the kernel mode register values.
  422          */
  423 #ifdef PAE
  424         pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdpt);
  425 #else
  426         pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdir);
  427 #endif
  428         pcb2->pcb_edi = 0;
  429         pcb2->pcb_esi = (int)fork_return;                   /* trampoline arg */
  430         pcb2->pcb_ebp = 0;
  431         pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
  432         pcb2->pcb_ebx = (int)td;                            /* trampoline arg */
  433         pcb2->pcb_eip = (int)fork_trampoline;
  434         pcb2->pcb_psl &= ~(PSL_I);      /* interrupts must be disabled */
  435         pcb2->pcb_gs = rgs();
  436         /*
  437          * If we didn't copy the pcb, we'd need to do the following registers:
  438          * pcb2->pcb_dr*:       cloned above.
  439          * pcb2->pcb_savefpu:   cloned above.
  440          * pcb2->pcb_flags:     cloned above.
  441          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  442          * pcb2->pcb_gs:        cloned above.  XXXKSE ???
  443          * pcb2->pcb_ext:       cleared below.
  444          */
  445         pcb2->pcb_ext = NULL;
  446 
  447         /* Setup to release spin count in fork_exit(). */
  448         td->td_md.md_spinlock_count = 1;
  449         td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  450 }
  451 
  452 /*
  453  * Set that machine state for performing an upcall that has to
  454  * be done in thread_userret() so that those upcalls generated
  455  * in thread_userret() itself can be done as well.
  456  */
  457 void
  458 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
  459         stack_t *stack)
  460 {
  461 
  462         /* 
  463          * Do any extra cleaning that needs to be done.
  464          * The thread may have optional components
  465          * that are not present in a fresh thread.
  466          * This may be a recycled thread so make it look
  467          * as though it's newly allocated.
  468          */
  469         cpu_thread_clean(td);
  470 
  471         /*
  472          * Set the trap frame to point at the beginning of the uts
  473          * function.
  474          */
  475         td->td_frame->tf_ebp = 0; 
  476         td->td_frame->tf_esp =
  477             (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
  478         td->td_frame->tf_eip = (int)entry;
  479 
  480         /*
  481          * Pass the address of the mailbox for this kse to the uts
  482          * function as a parameter on the stack.
  483          */
  484         suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
  485             (int)arg);
  486 }
  487 
  488 int
  489 cpu_set_user_tls(struct thread *td, void *tls_base)
  490 {
  491         struct segment_descriptor sd;
  492         uint32_t base;
  493 
  494         /*
  495          * Construct a descriptor and store it in the pcb for
  496          * the next context switch.  Also store it in the gdt
  497          * so that the load of tf_fs into %fs will activate it
  498          * at return to userland.
  499          */
  500         base = (uint32_t)tls_base;
  501         sd.sd_lobase = base & 0xffffff;
  502         sd.sd_hibase = (base >> 24) & 0xff;
  503         sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */
  504         sd.sd_hilimit = 0xf;
  505         sd.sd_type  = SDT_MEMRWA;
  506         sd.sd_dpl   = SEL_UPL;
  507         sd.sd_p     = 1;
  508         sd.sd_xx    = 0;
  509         sd.sd_def32 = 1;
  510         sd.sd_gran  = 1;
  511         critical_enter();
  512         /* set %gs */
  513         td->td_pcb->pcb_gsd = sd;
  514         if (td == curthread) {
  515                 PCPU_GET(fsgs_gdt)[1] = sd;
  516                 load_gs(GSEL(GUGS_SEL, SEL_UPL));
  517         }
  518         critical_exit();
  519         return (0);
  520 }
  521 
  522 /*
  523  * Convert kernel VA to physical address
  524  */
  525 vm_paddr_t
  526 kvtop(void *addr)
  527 {
  528         vm_paddr_t pa;
  529 
  530         pa = pmap_kextract((vm_offset_t)addr);
  531         if (pa == 0)
  532                 panic("kvtop: zero page frame");
  533         return (pa);
  534 }
  535 
  536 #ifdef SMP
  537 static void
  538 cpu_reset_proxy()
  539 {
  540 
  541         cpu_reset_proxy_active = 1;
  542         while (cpu_reset_proxy_active == 1)
  543                 ;       /* Wait for other cpu to see that we've started */
  544         stop_cpus((1<<cpu_reset_proxyid));
  545         printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
  546         DELAY(1000000);
  547         cpu_reset_real();
  548 }
  549 #endif
  550 
  551 void
  552 cpu_reset()
  553 {
  554 #ifdef XBOX
  555         if (arch_i386_is_xbox) {
  556                 /* Kick the PIC16L, it can reboot the box */
  557                 pic16l_reboot();
  558                 for (;;);
  559         }
  560 #endif
  561 
  562 #ifdef SMP
  563         u_int cnt, map;
  564 
  565         if (smp_active) {
  566                 map = PCPU_GET(other_cpus) & ~stopped_cpus;
  567                 if (map != 0) {
  568                         printf("cpu_reset: Stopping other CPUs\n");
  569                         stop_cpus(map);
  570                 }
  571 
  572                 if (PCPU_GET(cpuid) != 0) {
  573                         cpu_reset_proxyid = PCPU_GET(cpuid);
  574                         cpustop_restartfunc = cpu_reset_proxy;
  575                         cpu_reset_proxy_active = 0;
  576                         printf("cpu_reset: Restarting BSP\n");
  577 
  578                         /* Restart CPU #0. */
  579                         /* XXX: restart_cpus(1 << 0); */
  580                         atomic_store_rel_int(&started_cpus, (1 << 0));
  581 
  582                         cnt = 0;
  583                         while (cpu_reset_proxy_active == 0 && cnt < 10000000)
  584                                 cnt++;  /* Wait for BSP to announce restart */
  585                         if (cpu_reset_proxy_active == 0)
  586                                 printf("cpu_reset: Failed to restart BSP\n");
  587                         enable_intr();
  588                         cpu_reset_proxy_active = 2;
  589 
  590                         while (1);
  591                         /* NOTREACHED */
  592                 }
  593 
  594                 DELAY(1000000);
  595         }
  596 #endif
  597         cpu_reset_real();
  598         /* NOTREACHED */
  599 }
  600 
  601 static void
  602 cpu_reset_real()
  603 {
  604         struct region_descriptor null_idt;
  605 #ifndef PC98
  606         int b;
  607 #endif
  608 
  609         disable_intr();
  610 #ifdef CPU_ELAN
  611         if (elan_mmcr != NULL)
  612                 elan_mmcr->RESCFG = 1;
  613 #endif
  614 
  615         if (cpu == CPU_GEODE1100) {
  616                 /* Attempt Geode's own reset */
  617                 outl(0xcf8, 0x80009044ul);
  618                 outl(0xcfc, 0xf);
  619         }
  620 
  621 #ifdef PC98
  622         /*
  623          * Attempt to do a CPU reset via CPU reset port.
  624          */
  625         if ((inb(0x35) & 0xa0) != 0xa0) {
  626                 outb(0x37, 0x0f);               /* SHUT0 = 0. */
  627                 outb(0x37, 0x0b);               /* SHUT1 = 0. */
  628         }
  629         outb(0xf0, 0x00);               /* Reset. */
  630 #else
  631 #if !defined(BROKEN_KEYBOARD_RESET)
  632         /*
  633          * Attempt to do a CPU reset via the keyboard controller,
  634          * do not turn off GateA20, as any machine that fails
  635          * to do the reset here would then end up in no man's land.
  636          */
  637         outb(IO_KBD + 4, 0xFE);
  638         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  639 #endif
  640 
  641         /*
  642          * Attempt to force a reset via the Reset Control register at
  643          * I/O port 0xcf9.  Bit 2 forces a system reset when it
  644          * transitions from 0 to 1.  Bit 1 selects the type of reset
  645          * to attempt: 0 selects a "soft" reset, and 1 selects a
  646          * "hard" reset.  We try a "hard" reset.  The first write sets
  647          * bit 1 to select a "hard" reset and clears bit 2.  The
  648          * second write forces a 0 -> 1 transition in bit 2 to trigger
  649          * a reset.
  650          */
  651         outb(0xcf9, 0x2);
  652         outb(0xcf9, 0x6);
  653         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  654 
  655         /*
  656          * Attempt to force a reset via the Fast A20 and Init register
  657          * at I/O port 0x92.  Bit 1 serves as an alternate A20 gate.
  658          * Bit 0 asserts INIT# when set to 1.  We are careful to only
  659          * preserve bit 1 while setting bit 0.  We also must clear bit
  660          * 0 before setting it if it isn't already clear.
  661          */
  662         b = inb(0x92);
  663         if (b != 0xff) {
  664                 if ((b & 0x1) != 0)
  665                         outb(0x92, b & 0xfe);
  666                 outb(0x92, b | 0x1);
  667                 DELAY(500000);  /* wait 0.5 sec to see if that did it */
  668         }
  669 #endif /* PC98 */
  670 
  671         printf("No known reset method worked, attempting CPU shutdown\n");
  672         DELAY(1000000); /* wait 1 sec for printf to complete */
  673 
  674         /* Wipe the IDT. */
  675         null_idt.rd_limit = 0;
  676         null_idt.rd_base = 0;
  677         lidt(&null_idt);
  678 
  679         /* "good night, sweet prince .... <THUNK!>" */
  680         breakpoint();
  681 
  682         /* NOTREACHED */
  683         while(1);
  684 }
  685 
  686 /*
  687  * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
  688  */
  689 static void
  690 sf_buf_init(void *arg)
  691 {
  692         struct sf_buf *sf_bufs;
  693         vm_offset_t sf_base;
  694         int i;
  695 
  696         nsfbufs = NSFBUFS;
  697         TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
  698 
  699         sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
  700         TAILQ_INIT(&sf_buf_freelist);
  701         sf_base = kmem_alloc_nofault(kernel_map, nsfbufs * PAGE_SIZE);
  702         sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
  703             M_NOWAIT | M_ZERO);
  704         for (i = 0; i < nsfbufs; i++) {
  705                 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
  706                 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
  707         }
  708         sf_buf_alloc_want = 0;
  709         mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
  710 }
  711 
  712 /*
  713  * Invalidate the cache lines that may belong to the page, if
  714  * (possibly old) mapping of the page by sf buffer exists.  Returns
  715  * TRUE when mapping was found and cache invalidated.
  716  */
  717 boolean_t
  718 sf_buf_invalidate_cache(vm_page_t m)
  719 {
  720         struct sf_head *hash_list;
  721         struct sf_buf *sf;
  722         boolean_t ret;
  723 
  724         hash_list = &sf_buf_active[SF_BUF_HASH(m)];
  725         ret = FALSE;
  726         mtx_lock(&sf_buf_lock);
  727         LIST_FOREACH(sf, hash_list, list_entry) {
  728                 if (sf->m == m) {
  729                         /*
  730                          * Use pmap_qenter to update the pte for
  731                          * existing mapping, in particular, the PAT
  732                          * settings are recalculated.
  733                          */
  734                         pmap_qenter(sf->kva, &m, 1);
  735                         pmap_invalidate_cache_range(sf->kva, sf->kva +
  736                             PAGE_SIZE);
  737                         ret = TRUE;
  738                         break;
  739                 }
  740         }
  741         mtx_unlock(&sf_buf_lock);
  742         return (ret);
  743 }
  744 
  745 /*
  746  * Get an sf_buf from the freelist.  May block if none are available.
  747  */
  748 struct sf_buf *
  749 sf_buf_alloc(struct vm_page *m, int flags)
  750 {
  751         pt_entry_t opte, *ptep;
  752         struct sf_head *hash_list;
  753         struct sf_buf *sf;
  754 #ifdef SMP
  755         cpumask_t cpumask, other_cpus;
  756 #endif
  757         int error;
  758 
  759         KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
  760             ("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
  761         hash_list = &sf_buf_active[SF_BUF_HASH(m)];
  762         mtx_lock(&sf_buf_lock);
  763         LIST_FOREACH(sf, hash_list, list_entry) {
  764                 if (sf->m == m) {
  765                         sf->ref_count++;
  766                         if (sf->ref_count == 1) {
  767                                 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
  768                                 nsfbufsused++;
  769                                 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
  770                         }
  771 #ifdef SMP
  772                         goto shootdown; 
  773 #else
  774                         goto done;
  775 #endif
  776                 }
  777         }
  778         while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
  779                 if (flags & SFB_NOWAIT)
  780                         goto done;
  781                 sf_buf_alloc_want++;
  782                 mbstat.sf_allocwait++;
  783                 error = msleep(&sf_buf_freelist, &sf_buf_lock,
  784                     (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
  785                 sf_buf_alloc_want--;
  786 
  787                 /*
  788                  * If we got a signal, don't risk going back to sleep. 
  789                  */
  790                 if (error)
  791                         goto done;
  792         }
  793         TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
  794         if (sf->m != NULL)
  795                 LIST_REMOVE(sf, list_entry);
  796         LIST_INSERT_HEAD(hash_list, sf, list_entry);
  797         sf->ref_count = 1;
  798         sf->m = m;
  799         nsfbufsused++;
  800         nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
  801 
  802         /*
  803          * Update the sf_buf's virtual-to-physical mapping, flushing the
  804          * virtual address from the TLB.  Since the reference count for 
  805          * the sf_buf's old mapping was zero, that mapping is not 
  806          * currently in use.  Consequently, there is no need to exchange 
  807          * the old and new PTEs atomically, even under PAE.
  808          */
  809         ptep = vtopte(sf->kva);
  810         opte = *ptep;
  811         *ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V |
  812             pmap_cache_bits(m->md.pat_mode, 0);
  813 
  814         /*
  815          * Avoid unnecessary TLB invalidations: If the sf_buf's old
  816          * virtual-to-physical mapping was not used, then any processor
  817          * that has invalidated the sf_buf's virtual address from its TLB
  818          * since the last used mapping need not invalidate again.
  819          */
  820 #ifdef SMP
  821         if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
  822                 sf->cpumask = 0;
  823 shootdown:
  824         sched_pin();
  825         cpumask = PCPU_GET(cpumask);
  826         if ((sf->cpumask & cpumask) == 0) {
  827                 sf->cpumask |= cpumask;
  828                 invlpg(sf->kva);
  829         }
  830         if ((flags & SFB_CPUPRIVATE) == 0) {
  831                 other_cpus = PCPU_GET(other_cpus) & ~sf->cpumask;
  832                 if (other_cpus != 0) {
  833                         sf->cpumask |= other_cpus;
  834                         smp_masked_invlpg(other_cpus, sf->kva);
  835                 }
  836         }
  837         sched_unpin();  
  838 #else
  839         if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
  840                 pmap_invalidate_page(kernel_pmap, sf->kva);
  841 #endif
  842 done:
  843         mtx_unlock(&sf_buf_lock);
  844         return (sf);
  845 }
  846 
  847 /*
  848  * Remove a reference from the given sf_buf, adding it to the free
  849  * list when its reference count reaches zero.  A freed sf_buf still,
  850  * however, retains its virtual-to-physical mapping until it is
  851  * recycled or reactivated by sf_buf_alloc(9).
  852  */
  853 void
  854 sf_buf_free(struct sf_buf *sf)
  855 {
  856 
  857         mtx_lock(&sf_buf_lock);
  858         sf->ref_count--;
  859         if (sf->ref_count == 0) {
  860                 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
  861                 nsfbufsused--;
  862                 if (sf_buf_alloc_want > 0)
  863                         wakeup_one(&sf_buf_freelist);
  864         }
  865         mtx_unlock(&sf_buf_lock);
  866 }
  867 
  868 /*
  869  * Software interrupt handler for queued VM system processing.
  870  */   
  871 void  
  872 swi_vm(void *dummy) 
  873 {     
  874         if (busdma_swi_pending != 0)
  875                 busdma_swi();
  876 }
  877 
  878 /*
  879  * Tell whether this address is in some physical memory region.
  880  * Currently used by the kernel coredump code in order to avoid
  881  * dumping the ``ISA memory hole'' which could cause indefinite hangs,
  882  * or other unpredictable behaviour.
  883  */
  884 
  885 int
  886 is_physical_memory(vm_paddr_t addr)
  887 {
  888 
  889 #ifdef DEV_ISA
  890         /* The ISA ``memory hole''. */
  891         if (addr >= 0xa0000 && addr < 0x100000)
  892                 return 0;
  893 #endif
  894 
  895         /*
  896          * stuff other tests for known memory-mapped devices (PCI?)
  897          * here
  898          */
  899 
  900         return 1;
  901 }

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