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/10.3/sys/i386/i386/vm_machdep.c 296945 2016-03-16 17:01:24Z kib $");
   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/kernel.h>
   57 #include <sys/ktr.h>
   58 #include <sys/lock.h>
   59 #include <sys/malloc.h>
   60 #include <sys/mbuf.h>
   61 #include <sys/mutex.h>
   62 #include <sys/pioctl.h>
   63 #include <sys/proc.h>
   64 #include <sys/sysent.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 XEN
   93 #include <xen/hypervisor.h>
   94 #endif
   95 #ifdef PC98
   96 #include <pc98/cbus/cbus.h>
   97 #else
   98 #include <x86/isa/isa.h>
   99 #endif
  100 
  101 #ifdef XBOX
  102 #include <machine/xbox.h>
  103 #endif
  104 
  105 #ifndef NSFBUFS
  106 #define NSFBUFS         (512 + maxusers * 16)
  107 #endif
  108 
  109 #if !defined(CPU_DISABLE_SSE) && defined(I686_CPU)
  110 #define CPU_ENABLE_SSE
  111 #endif
  112 
  113 _Static_assert(OFFSETOF_CURTHREAD == offsetof(struct pcpu, pc_curthread),
  114     "OFFSETOF_CURTHREAD does not correspond with offset of pc_curthread.");
  115 _Static_assert(OFFSETOF_CURPCB == offsetof(struct pcpu, pc_curpcb),
  116     "OFFSETOF_CURPCB does not correspond with offset of pc_curpcb.");
  117 
  118 static void     cpu_reset_real(void);
  119 #ifdef SMP
  120 static void     cpu_reset_proxy(void);
  121 static u_int    cpu_reset_proxyid;
  122 static volatile u_int   cpu_reset_proxy_active;
  123 #endif
  124 
  125 static int nsfbufs;
  126 static int nsfbufspeak;
  127 static int nsfbufsused;
  128 
  129 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RDTUN, &nsfbufs, 0,
  130     "Maximum number of sendfile(2) sf_bufs available");
  131 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufspeak, CTLFLAG_RD, &nsfbufspeak, 0,
  132     "Number of sendfile(2) sf_bufs at peak usage");
  133 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufsused, CTLFLAG_RD, &nsfbufsused, 0,
  134     "Number of sendfile(2) sf_bufs in use");
  135 
  136 static void     sf_buf_init(void *arg);
  137 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
  138 
  139 LIST_HEAD(sf_head, sf_buf);
  140 
  141 /*
  142  * A hash table of active sendfile(2) buffers
  143  */
  144 static struct sf_head *sf_buf_active;
  145 static u_long sf_buf_hashmask;
  146 
  147 #define SF_BUF_HASH(m)  (((m) - vm_page_array) & sf_buf_hashmask)
  148 
  149 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
  150 static u_int    sf_buf_alloc_want;
  151 
  152 /*
  153  * A lock used to synchronize access to the hash table and free list
  154  */
  155 static struct mtx sf_buf_lock;
  156 
  157 union savefpu *
  158 get_pcb_user_save_td(struct thread *td)
  159 {
  160         vm_offset_t p;
  161         p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
  162             roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
  163         KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
  164         return ((union savefpu *)p);
  165 }
  166 
  167 union savefpu *
  168 get_pcb_user_save_pcb(struct pcb *pcb)
  169 {
  170         vm_offset_t p;
  171 
  172         p = (vm_offset_t)(pcb + 1);
  173         return ((union savefpu *)p);
  174 }
  175 
  176 struct pcb *
  177 get_pcb_td(struct thread *td)
  178 {
  179         vm_offset_t p;
  180 
  181         p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
  182             roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
  183             sizeof(struct pcb);
  184         return ((struct pcb *)p);
  185 }
  186 
  187 void *
  188 alloc_fpusave(int flags)
  189 {
  190         void *res;
  191 #ifdef CPU_ENABLE_SSE
  192         struct savefpu_ymm *sf;
  193 #endif
  194 
  195         res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags);
  196 #ifdef CPU_ENABLE_SSE
  197         if (use_xsave) {
  198                 sf = (struct savefpu_ymm *)res;
  199                 bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd));
  200                 sf->sv_xstate.sx_hd.xstate_bv = xsave_mask;
  201         }
  202 #endif
  203         return (res);
  204 }
  205 
  206 /*
  207  * Finish a fork operation, with process p2 nearly set up.
  208  * Copy and update the pcb, set up the stack so that the child
  209  * ready to run and return to user mode.
  210  */
  211 void
  212 cpu_fork(td1, p2, td2, flags)
  213         register struct thread *td1;
  214         register struct proc *p2;
  215         struct thread *td2;
  216         int flags;
  217 {
  218         register struct proc *p1;
  219         struct pcb *pcb2;
  220         struct mdproc *mdp2;
  221 
  222         p1 = td1->td_proc;
  223         if ((flags & RFPROC) == 0) {
  224                 if ((flags & RFMEM) == 0) {
  225                         /* unshare user LDT */
  226                         struct mdproc *mdp1 = &p1->p_md;
  227                         struct proc_ldt *pldt, *pldt1;
  228 
  229                         mtx_lock_spin(&dt_lock);
  230                         if ((pldt1 = mdp1->md_ldt) != NULL &&
  231                             pldt1->ldt_refcnt > 1) {
  232                                 pldt = user_ldt_alloc(mdp1, pldt1->ldt_len);
  233                                 if (pldt == NULL)
  234                                         panic("could not copy LDT");
  235                                 mdp1->md_ldt = pldt;
  236                                 set_user_ldt(mdp1);
  237                                 user_ldt_deref(pldt1);
  238                         } else
  239                                 mtx_unlock_spin(&dt_lock);
  240                 }
  241                 return;
  242         }
  243 
  244         /* Ensure that td1's pcb is up to date. */
  245         if (td1 == curthread)
  246                 td1->td_pcb->pcb_gs = rgs();
  247 #ifdef DEV_NPX
  248         critical_enter();
  249         if (PCPU_GET(fpcurthread) == td1)
  250                 npxsave(td1->td_pcb->pcb_save);
  251         critical_exit();
  252 #endif
  253 
  254         /* Point the pcb to the top of the stack */
  255         pcb2 = get_pcb_td(td2);
  256         td2->td_pcb = pcb2;
  257 
  258         /* Copy td1's pcb */
  259         bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
  260 
  261         /* Properly initialize pcb_save */
  262         pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
  263         bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2),
  264             cpu_max_ext_state_size);
  265 
  266         /* Point mdproc and then copy over td1's contents */
  267         mdp2 = &p2->p_md;
  268         bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
  269 
  270         /*
  271          * Create a new fresh stack for the new process.
  272          * Copy the trap frame for the return to user mode as if from a
  273          * syscall.  This copies most of the user mode register values.
  274          * The -16 is so we can expand the trapframe if we go to vm86.
  275          */
  276         td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
  277         bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
  278 
  279         td2->td_frame->tf_eax = 0;              /* Child returns zero */
  280         td2->td_frame->tf_eflags &= ~PSL_C;     /* success */
  281         td2->td_frame->tf_edx = 1;
  282 
  283         /*
  284          * If the parent process has the trap bit set (i.e. a debugger had
  285          * single stepped the process to the system call), we need to clear
  286          * the trap flag from the new frame unless the debugger had set PF_FORK
  287          * on the parent.  Otherwise, the child will receive a (likely
  288          * unexpected) SIGTRAP when it executes the first instruction after
  289          * returning  to userland.
  290          */
  291         if ((p1->p_pfsflags & PF_FORK) == 0)
  292                 td2->td_frame->tf_eflags &= ~PSL_T;
  293 
  294         /*
  295          * Set registers for trampoline to user mode.  Leave space for the
  296          * return address on stack.  These are the kernel mode register values.
  297          */
  298 #if defined(PAE) || defined(PAE_TABLES)
  299         pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
  300 #else
  301         pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
  302 #endif
  303         pcb2->pcb_edi = 0;
  304         pcb2->pcb_esi = (int)fork_return;       /* fork_trampoline argument */
  305         pcb2->pcb_ebp = 0;
  306         pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
  307         pcb2->pcb_ebx = (int)td2;               /* fork_trampoline argument */
  308         pcb2->pcb_eip = (int)fork_trampoline;
  309         pcb2->pcb_psl = PSL_KERNEL;             /* ints disabled */
  310         /*-
  311          * pcb2->pcb_dr*:       cloned above.
  312          * pcb2->pcb_savefpu:   cloned above.
  313          * pcb2->pcb_flags:     cloned above.
  314          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  315          * pcb2->pcb_gs:        cloned above.
  316          * pcb2->pcb_ext:       cleared below.
  317          */
  318 
  319         /*
  320          * XXX don't copy the i/o pages.  this should probably be fixed.
  321          */
  322         pcb2->pcb_ext = 0;
  323 
  324         /* Copy the LDT, if necessary. */
  325         mtx_lock_spin(&dt_lock);
  326         if (mdp2->md_ldt != NULL) {
  327                 if (flags & RFMEM) {
  328                         mdp2->md_ldt->ldt_refcnt++;
  329                 } else {
  330                         mdp2->md_ldt = user_ldt_alloc(mdp2,
  331                             mdp2->md_ldt->ldt_len);
  332                         if (mdp2->md_ldt == NULL)
  333                                 panic("could not copy LDT");
  334                 }
  335         }
  336         mtx_unlock_spin(&dt_lock);
  337 
  338         /* Setup to release spin count in fork_exit(). */
  339         td2->td_md.md_spinlock_count = 1;
  340         /*
  341          * XXX XEN need to check on PSL_USER is handled
  342          */
  343         td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  344         /*
  345          * Now, cpu_switch() can schedule the new process.
  346          * pcb_esp is loaded pointing to the cpu_switch() stack frame
  347          * containing the return address when exiting cpu_switch.
  348          * This will normally be to fork_trampoline(), which will have
  349          * %ebx loaded with the new proc's pointer.  fork_trampoline()
  350          * will set up a stack to call fork_return(p, frame); to complete
  351          * the return to user-mode.
  352          */
  353 }
  354 
  355 /*
  356  * Intercept the return address from a freshly forked process that has NOT
  357  * been scheduled yet.
  358  *
  359  * This is needed to make kernel threads stay in kernel mode.
  360  */
  361 void
  362 cpu_set_fork_handler(td, func, arg)
  363         struct thread *td;
  364         void (*func)(void *);
  365         void *arg;
  366 {
  367         /*
  368          * Note that the trap frame follows the args, so the function
  369          * is really called like this:  func(arg, frame);
  370          */
  371         td->td_pcb->pcb_esi = (int) func;       /* function */
  372         td->td_pcb->pcb_ebx = (int) arg;        /* first arg */
  373 }
  374 
  375 void
  376 cpu_exit(struct thread *td)
  377 {
  378 
  379         /*
  380          * If this process has a custom LDT, release it.  Reset pc->pcb_gs
  381          * and %gs before we free it in case they refer to an LDT entry.
  382          */
  383         mtx_lock_spin(&dt_lock);
  384         if (td->td_proc->p_md.md_ldt) {
  385                 td->td_pcb->pcb_gs = _udatasel;
  386                 load_gs(_udatasel);
  387                 user_ldt_free(td);
  388         } else
  389                 mtx_unlock_spin(&dt_lock);
  390 }
  391 
  392 void
  393 cpu_thread_exit(struct thread *td)
  394 {
  395 
  396 #ifdef DEV_NPX
  397         critical_enter();
  398         if (td == PCPU_GET(fpcurthread))
  399                 npxdrop();
  400         critical_exit();
  401 #endif
  402 
  403         /* Disable any hardware breakpoints. */
  404         if (td->td_pcb->pcb_flags & PCB_DBREGS) {
  405                 reset_dbregs();
  406                 td->td_pcb->pcb_flags &= ~PCB_DBREGS;
  407         }
  408 }
  409 
  410 void
  411 cpu_thread_clean(struct thread *td)
  412 {
  413         struct pcb *pcb;
  414 
  415         pcb = td->td_pcb; 
  416         if (pcb->pcb_ext != NULL) {
  417                 /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
  418                 /*
  419                  * XXX do we need to move the TSS off the allocated pages
  420                  * before freeing them?  (not done here)
  421                  */
  422                 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_ext,
  423                     ctob(IOPAGES + 1));
  424                 pcb->pcb_ext = NULL;
  425         }
  426 }
  427 
  428 void
  429 cpu_thread_swapin(struct thread *td)
  430 {
  431 }
  432 
  433 void
  434 cpu_thread_swapout(struct thread *td)
  435 {
  436 }
  437 
  438 void
  439 cpu_thread_alloc(struct thread *td)
  440 {
  441         struct pcb *pcb;
  442 #ifdef CPU_ENABLE_SSE
  443         struct xstate_hdr *xhdr;
  444 #endif
  445 
  446         td->td_pcb = pcb = get_pcb_td(td);
  447         td->td_frame = (struct trapframe *)((caddr_t)pcb - 16) - 1;
  448         pcb->pcb_ext = NULL; 
  449         pcb->pcb_save = get_pcb_user_save_pcb(pcb);
  450 #ifdef CPU_ENABLE_SSE
  451         if (use_xsave) {
  452                 xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1);
  453                 bzero(xhdr, sizeof(*xhdr));
  454                 xhdr->xstate_bv = xsave_mask;
  455         }
  456 #endif
  457 }
  458 
  459 void
  460 cpu_thread_free(struct thread *td)
  461 {
  462 
  463         cpu_thread_clean(td);
  464 }
  465 
  466 void
  467 cpu_set_syscall_retval(struct thread *td, int error)
  468 {
  469 
  470         switch (error) {
  471         case 0:
  472                 td->td_frame->tf_eax = td->td_retval[0];
  473                 td->td_frame->tf_edx = td->td_retval[1];
  474                 td->td_frame->tf_eflags &= ~PSL_C;
  475                 break;
  476 
  477         case ERESTART:
  478                 /*
  479                  * Reconstruct pc, assuming lcall $X,y is 7 bytes, int
  480                  * 0x80 is 2 bytes. We saved this in tf_err.
  481                  */
  482                 td->td_frame->tf_eip -= td->td_frame->tf_err;
  483                 break;
  484 
  485         case EJUSTRETURN:
  486                 break;
  487 
  488         default:
  489                 if (td->td_proc->p_sysent->sv_errsize) {
  490                         if (error >= td->td_proc->p_sysent->sv_errsize)
  491                                 error = -1;     /* XXX */
  492                         else
  493                                 error = td->td_proc->p_sysent->sv_errtbl[error];
  494                 }
  495                 td->td_frame->tf_eax = error;
  496                 td->td_frame->tf_eflags |= PSL_C;
  497                 break;
  498         }
  499 }
  500 
  501 /*
  502  * Initialize machine state (pcb and trap frame) for a new thread about to
  503  * upcall. Put enough state in the new thread's PCB to get it to go back 
  504  * userret(), where we can intercept it again to set the return (upcall)
  505  * Address and stack, along with those from upcals that are from other sources
  506  * such as those generated in thread_userret() itself.
  507  */
  508 void
  509 cpu_set_upcall(struct thread *td, struct thread *td0)
  510 {
  511         struct pcb *pcb2;
  512 
  513         /* Point the pcb to the top of the stack. */
  514         pcb2 = td->td_pcb;
  515 
  516         /*
  517          * Copy the upcall pcb.  This loads kernel regs.
  518          * Those not loaded individually below get their default
  519          * values here.
  520          */
  521         bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
  522         pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE |
  523             PCB_KERNNPX);
  524         pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
  525         bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save,
  526             cpu_max_ext_state_size);
  527 
  528         /*
  529          * Create a new fresh stack for the new thread.
  530          */
  531         bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
  532 
  533         /* If the current thread has the trap bit set (i.e. a debugger had
  534          * single stepped the process to the system call), we need to clear
  535          * the trap flag from the new frame. Otherwise, the new thread will
  536          * receive a (likely unexpected) SIGTRAP when it executes the first
  537          * instruction after returning to userland.
  538          */
  539         td->td_frame->tf_eflags &= ~PSL_T;
  540 
  541         /*
  542          * Set registers for trampoline to user mode.  Leave space for the
  543          * return address on stack.  These are the kernel mode register values.
  544          */
  545         pcb2->pcb_edi = 0;
  546         pcb2->pcb_esi = (int)fork_return;                   /* trampoline arg */
  547         pcb2->pcb_ebp = 0;
  548         pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
  549         pcb2->pcb_ebx = (int)td;                            /* trampoline arg */
  550         pcb2->pcb_eip = (int)fork_trampoline;
  551         pcb2->pcb_psl &= ~(PSL_I);      /* interrupts must be disabled */
  552         pcb2->pcb_gs = rgs();
  553         /*
  554          * If we didn't copy the pcb, we'd need to do the following registers:
  555          * pcb2->pcb_cr3:       cloned above.
  556          * pcb2->pcb_dr*:       cloned above.
  557          * pcb2->pcb_savefpu:   cloned above.
  558          * pcb2->pcb_flags:     cloned above.
  559          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  560          * pcb2->pcb_gs:        cloned above.
  561          * pcb2->pcb_ext:       cleared below.
  562          */
  563         pcb2->pcb_ext = NULL;
  564 
  565         /* Setup to release spin count in fork_exit(). */
  566         td->td_md.md_spinlock_count = 1;
  567         td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  568 }
  569 
  570 /*
  571  * Set that machine state for performing an upcall that has to
  572  * be done in thread_userret() so that those upcalls generated
  573  * in thread_userret() itself can be done as well.
  574  */
  575 void
  576 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
  577         stack_t *stack)
  578 {
  579 
  580         /* 
  581          * Do any extra cleaning that needs to be done.
  582          * The thread may have optional components
  583          * that are not present in a fresh thread.
  584          * This may be a recycled thread so make it look
  585          * as though it's newly allocated.
  586          */
  587         cpu_thread_clean(td);
  588 
  589         /*
  590          * Set the trap frame to point at the beginning of the uts
  591          * function.
  592          */
  593         td->td_frame->tf_ebp = 0; 
  594         td->td_frame->tf_esp =
  595             (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
  596         td->td_frame->tf_eip = (int)entry;
  597 
  598         /*
  599          * Pass the address of the mailbox for this kse to the uts
  600          * function as a parameter on the stack.
  601          */
  602         suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
  603             (int)arg);
  604 }
  605 
  606 int
  607 cpu_set_user_tls(struct thread *td, void *tls_base)
  608 {
  609         struct segment_descriptor sd;
  610         uint32_t base;
  611 
  612         /*
  613          * Construct a descriptor and store it in the pcb for
  614          * the next context switch.  Also store it in the gdt
  615          * so that the load of tf_fs into %fs will activate it
  616          * at return to userland.
  617          */
  618         base = (uint32_t)tls_base;
  619         sd.sd_lobase = base & 0xffffff;
  620         sd.sd_hibase = (base >> 24) & 0xff;
  621         sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */
  622         sd.sd_hilimit = 0xf;
  623         sd.sd_type  = SDT_MEMRWA;
  624         sd.sd_dpl   = SEL_UPL;
  625         sd.sd_p     = 1;
  626         sd.sd_xx    = 0;
  627         sd.sd_def32 = 1;
  628         sd.sd_gran  = 1;
  629         critical_enter();
  630         /* set %gs */
  631         td->td_pcb->pcb_gsd = sd;
  632         if (td == curthread) {
  633                 PCPU_GET(fsgs_gdt)[1] = sd;
  634                 load_gs(GSEL(GUGS_SEL, SEL_UPL));
  635         }
  636         critical_exit();
  637         return (0);
  638 }
  639 
  640 /*
  641  * Convert kernel VA to physical address
  642  */
  643 vm_paddr_t
  644 kvtop(void *addr)
  645 {
  646         vm_paddr_t pa;
  647 
  648         pa = pmap_kextract((vm_offset_t)addr);
  649         if (pa == 0)
  650                 panic("kvtop: zero page frame");
  651         return (pa);
  652 }
  653 
  654 #ifdef SMP
  655 static void
  656 cpu_reset_proxy()
  657 {
  658         cpuset_t tcrp;
  659 
  660         cpu_reset_proxy_active = 1;
  661         while (cpu_reset_proxy_active == 1)
  662                 ;       /* Wait for other cpu to see that we've started */
  663         CPU_SETOF(cpu_reset_proxyid, &tcrp);
  664         stop_cpus(tcrp);
  665         printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
  666         DELAY(1000000);
  667         cpu_reset_real();
  668 }
  669 #endif
  670 
  671 void
  672 cpu_reset()
  673 {
  674 #ifdef XBOX
  675         if (arch_i386_is_xbox) {
  676                 /* Kick the PIC16L, it can reboot the box */
  677                 pic16l_reboot();
  678                 for (;;);
  679         }
  680 #endif
  681 
  682 #ifdef SMP
  683         cpuset_t map;
  684         u_int cnt;
  685 
  686         if (smp_started) {
  687                 map = all_cpus;
  688                 CPU_CLR(PCPU_GET(cpuid), &map);
  689                 CPU_NAND(&map, &stopped_cpus);
  690                 if (!CPU_EMPTY(&map)) {
  691                         printf("cpu_reset: Stopping other CPUs\n");
  692                         stop_cpus(map);
  693                 }
  694 
  695                 if (PCPU_GET(cpuid) != 0) {
  696                         cpu_reset_proxyid = PCPU_GET(cpuid);
  697                         cpustop_restartfunc = cpu_reset_proxy;
  698                         cpu_reset_proxy_active = 0;
  699                         printf("cpu_reset: Restarting BSP\n");
  700 
  701                         /* Restart CPU #0. */
  702                         /* XXX: restart_cpus(1 << 0); */
  703                         CPU_SETOF(0, &started_cpus);
  704                         wmb();
  705 
  706                         cnt = 0;
  707                         while (cpu_reset_proxy_active == 0 && cnt < 10000000)
  708                                 cnt++;  /* Wait for BSP to announce restart */
  709                         if (cpu_reset_proxy_active == 0)
  710                                 printf("cpu_reset: Failed to restart BSP\n");
  711                         enable_intr();
  712                         cpu_reset_proxy_active = 2;
  713 
  714                         while (1);
  715                         /* NOTREACHED */
  716                 }
  717 
  718                 DELAY(1000000);
  719         }
  720 #endif
  721         cpu_reset_real();
  722         /* NOTREACHED */
  723 }
  724 
  725 static void
  726 cpu_reset_real()
  727 {
  728         struct region_descriptor null_idt;
  729 #ifndef PC98
  730         int b;
  731 #endif
  732 
  733         disable_intr();
  734 #ifdef XEN
  735         if (smp_processor_id() == 0)
  736                 HYPERVISOR_shutdown(SHUTDOWN_reboot);
  737         else
  738                 HYPERVISOR_shutdown(SHUTDOWN_poweroff);
  739 #endif 
  740 #ifdef CPU_ELAN
  741         if (elan_mmcr != NULL)
  742                 elan_mmcr->RESCFG = 1;
  743 #endif
  744 
  745         if (cpu == CPU_GEODE1100) {
  746                 /* Attempt Geode's own reset */
  747                 outl(0xcf8, 0x80009044ul);
  748                 outl(0xcfc, 0xf);
  749         }
  750 
  751 #ifdef PC98
  752         /*
  753          * Attempt to do a CPU reset via CPU reset port.
  754          */
  755         if ((inb(0x35) & 0xa0) != 0xa0) {
  756                 outb(0x37, 0x0f);               /* SHUT0 = 0. */
  757                 outb(0x37, 0x0b);               /* SHUT1 = 0. */
  758         }
  759         outb(0xf0, 0x00);               /* Reset. */
  760 #else
  761 #if !defined(BROKEN_KEYBOARD_RESET)
  762         /*
  763          * Attempt to do a CPU reset via the keyboard controller,
  764          * do not turn off GateA20, as any machine that fails
  765          * to do the reset here would then end up in no man's land.
  766          */
  767         outb(IO_KBD + 4, 0xFE);
  768         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  769 #endif
  770 
  771         /*
  772          * Attempt to force a reset via the Reset Control register at
  773          * I/O port 0xcf9.  Bit 2 forces a system reset when it
  774          * transitions from 0 to 1.  Bit 1 selects the type of reset
  775          * to attempt: 0 selects a "soft" reset, and 1 selects a
  776          * "hard" reset.  We try a "hard" reset.  The first write sets
  777          * bit 1 to select a "hard" reset and clears bit 2.  The
  778          * second write forces a 0 -> 1 transition in bit 2 to trigger
  779          * a reset.
  780          */
  781         outb(0xcf9, 0x2);
  782         outb(0xcf9, 0x6);
  783         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  784 
  785         /*
  786          * Attempt to force a reset via the Fast A20 and Init register
  787          * at I/O port 0x92.  Bit 1 serves as an alternate A20 gate.
  788          * Bit 0 asserts INIT# when set to 1.  We are careful to only
  789          * preserve bit 1 while setting bit 0.  We also must clear bit
  790          * 0 before setting it if it isn't already clear.
  791          */
  792         b = inb(0x92);
  793         if (b != 0xff) {
  794                 if ((b & 0x1) != 0)
  795                         outb(0x92, b & 0xfe);
  796                 outb(0x92, b | 0x1);
  797                 DELAY(500000);  /* wait 0.5 sec to see if that did it */
  798         }
  799 #endif /* PC98 */
  800 
  801         printf("No known reset method worked, attempting CPU shutdown\n");
  802         DELAY(1000000); /* wait 1 sec for printf to complete */
  803 
  804         /* Wipe the IDT. */
  805         null_idt.rd_limit = 0;
  806         null_idt.rd_base = 0;
  807         lidt(&null_idt);
  808 
  809         /* "good night, sweet prince .... <THUNK!>" */
  810         breakpoint();
  811 
  812         /* NOTREACHED */
  813         while(1);
  814 }
  815 
  816 /*
  817  * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
  818  */
  819 static void
  820 sf_buf_init(void *arg)
  821 {
  822         struct sf_buf *sf_bufs;
  823         vm_offset_t sf_base;
  824         int i;
  825 
  826         nsfbufs = NSFBUFS;
  827         TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
  828 
  829         sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
  830         TAILQ_INIT(&sf_buf_freelist);
  831         sf_base = kva_alloc(nsfbufs * PAGE_SIZE);
  832         sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
  833             M_NOWAIT | M_ZERO);
  834         for (i = 0; i < nsfbufs; i++) {
  835                 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
  836                 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
  837         }
  838         sf_buf_alloc_want = 0;
  839         mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
  840 }
  841 
  842 /*
  843  * Invalidate the cache lines that may belong to the page, if
  844  * (possibly old) mapping of the page by sf buffer exists.  Returns
  845  * TRUE when mapping was found and cache invalidated.
  846  */
  847 boolean_t
  848 sf_buf_invalidate_cache(vm_page_t m)
  849 {
  850         struct sf_head *hash_list;
  851         struct sf_buf *sf;
  852         boolean_t ret;
  853 
  854         hash_list = &sf_buf_active[SF_BUF_HASH(m)];
  855         ret = FALSE;
  856         mtx_lock(&sf_buf_lock);
  857         LIST_FOREACH(sf, hash_list, list_entry) {
  858                 if (sf->m == m) {
  859                         /*
  860                          * Use pmap_qenter to update the pte for
  861                          * existing mapping, in particular, the PAT
  862                          * settings are recalculated.
  863                          */
  864                         pmap_qenter(sf->kva, &m, 1);
  865                         pmap_invalidate_cache_range(sf->kva, sf->kva +
  866                             PAGE_SIZE, FALSE);
  867                         ret = TRUE;
  868                         break;
  869                 }
  870         }
  871         mtx_unlock(&sf_buf_lock);
  872         return (ret);
  873 }
  874 
  875 /*
  876  * Get an sf_buf from the freelist.  May block if none are available.
  877  */
  878 struct sf_buf *
  879 sf_buf_alloc(struct vm_page *m, int flags)
  880 {
  881         pt_entry_t opte, *ptep;
  882         struct sf_head *hash_list;
  883         struct sf_buf *sf;
  884 #ifdef SMP
  885         cpuset_t other_cpus;
  886         u_int cpuid;
  887 #endif
  888         int error;
  889 
  890         KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
  891             ("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
  892         hash_list = &sf_buf_active[SF_BUF_HASH(m)];
  893         mtx_lock(&sf_buf_lock);
  894         LIST_FOREACH(sf, hash_list, list_entry) {
  895                 if (sf->m == m) {
  896                         sf->ref_count++;
  897                         if (sf->ref_count == 1) {
  898                                 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
  899                                 nsfbufsused++;
  900                                 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
  901                         }
  902 #ifdef SMP
  903                         goto shootdown; 
  904 #else
  905                         goto done;
  906 #endif
  907                 }
  908         }
  909         while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
  910                 if (flags & SFB_NOWAIT)
  911                         goto done;
  912                 sf_buf_alloc_want++;
  913                 SFSTAT_INC(sf_allocwait);
  914                 error = msleep(&sf_buf_freelist, &sf_buf_lock,
  915                     (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
  916                 sf_buf_alloc_want--;
  917 
  918                 /*
  919                  * If we got a signal, don't risk going back to sleep. 
  920                  */
  921                 if (error)
  922                         goto done;
  923         }
  924         TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
  925         if (sf->m != NULL)
  926                 LIST_REMOVE(sf, list_entry);
  927         LIST_INSERT_HEAD(hash_list, sf, list_entry);
  928         sf->ref_count = 1;
  929         sf->m = m;
  930         nsfbufsused++;
  931         nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
  932 
  933         /*
  934          * Update the sf_buf's virtual-to-physical mapping, flushing the
  935          * virtual address from the TLB.  Since the reference count for 
  936          * the sf_buf's old mapping was zero, that mapping is not 
  937          * currently in use.  Consequently, there is no need to exchange 
  938          * the old and new PTEs atomically, even under PAE.
  939          */
  940         ptep = vtopte(sf->kva);
  941         opte = *ptep;
  942 #ifdef XEN
  943        PT_SET_MA(sf->kva, xpmap_ptom(VM_PAGE_TO_PHYS(m)) | pgeflag
  944            | PG_RW | PG_V | pmap_cache_bits(m->md.pat_mode, 0));
  945 #else
  946         *ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V |
  947             pmap_cache_bits(m->md.pat_mode, 0);
  948 #endif
  949 
  950         /*
  951          * Avoid unnecessary TLB invalidations: If the sf_buf's old
  952          * virtual-to-physical mapping was not used, then any processor
  953          * that has invalidated the sf_buf's virtual address from its TLB
  954          * since the last used mapping need not invalidate again.
  955          */
  956 #ifdef SMP
  957         if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
  958                 CPU_ZERO(&sf->cpumask);
  959 shootdown:
  960         sched_pin();
  961         cpuid = PCPU_GET(cpuid);
  962         if (!CPU_ISSET(cpuid, &sf->cpumask)) {
  963                 CPU_SET(cpuid, &sf->cpumask);
  964                 invlpg(sf->kva);
  965         }
  966         if ((flags & SFB_CPUPRIVATE) == 0) {
  967                 other_cpus = all_cpus;
  968                 CPU_CLR(cpuid, &other_cpus);
  969                 CPU_NAND(&other_cpus, &sf->cpumask);
  970                 if (!CPU_EMPTY(&other_cpus)) {
  971                         CPU_OR(&sf->cpumask, &other_cpus);
  972                         smp_masked_invlpg(other_cpus, sf->kva);
  973                 }
  974         }
  975         sched_unpin();
  976 #else
  977         if ((opte & (PG_V | PG_A)) ==  (PG_V | PG_A))
  978                 pmap_invalidate_page(kernel_pmap, sf->kva);
  979 #endif
  980 done:
  981         mtx_unlock(&sf_buf_lock);
  982         return (sf);
  983 }
  984 
  985 /*
  986  * Remove a reference from the given sf_buf, adding it to the free
  987  * list when its reference count reaches zero.  A freed sf_buf still,
  988  * however, retains its virtual-to-physical mapping until it is
  989  * recycled or reactivated by sf_buf_alloc(9).
  990  */
  991 void
  992 sf_buf_free(struct sf_buf *sf)
  993 {
  994 
  995         mtx_lock(&sf_buf_lock);
  996         sf->ref_count--;
  997         if (sf->ref_count == 0) {
  998                 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
  999                 nsfbufsused--;
 1000 #ifdef XEN
 1001 /*
 1002  * Xen doesn't like having dangling R/W mappings
 1003  */
 1004                 pmap_qremove(sf->kva, 1);
 1005                 sf->m = NULL;
 1006                 LIST_REMOVE(sf, list_entry);
 1007 #endif
 1008                 if (sf_buf_alloc_want > 0)
 1009                         wakeup(&sf_buf_freelist);
 1010         }
 1011         mtx_unlock(&sf_buf_lock);
 1012 }
 1013 
 1014 /*
 1015  * Software interrupt handler for queued VM system processing.
 1016  */   
 1017 void  
 1018 swi_vm(void *dummy) 
 1019 {     
 1020         if (busdma_swi_pending != 0)
 1021                 busdma_swi();
 1022 }
 1023 
 1024 /*
 1025  * Tell whether this address is in some physical memory region.
 1026  * Currently used by the kernel coredump code in order to avoid
 1027  * dumping the ``ISA memory hole'' which could cause indefinite hangs,
 1028  * or other unpredictable behaviour.
 1029  */
 1030 
 1031 int
 1032 is_physical_memory(vm_paddr_t addr)
 1033 {
 1034 
 1035 #ifdef DEV_ISA
 1036         /* The ISA ``memory hole''. */
 1037         if (addr >= 0xa0000 && addr < 0x100000)
 1038                 return 0;
 1039 #endif
 1040 
 1041         /*
 1042          * stuff other tests for known memory-mapped devices (PCI?)
 1043          * here
 1044          */
 1045 
 1046         return 1;
 1047 }

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