The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/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: src/sys/amd64/amd64/vm_machdep.c,v 1.237.2.2 2005/02/28 07:54:17 obrien Exp $");
   45 
   46 #include "opt_isa.h"
   47 #include "opt_cpu.h"
   48 
   49 #include <sys/param.h>
   50 #include <sys/systm.h>
   51 #include <sys/bio.h>
   52 #include <sys/buf.h>
   53 #include <sys/kse.h>
   54 #include <sys/kernel.h>
   55 #include <sys/ktr.h>
   56 #include <sys/lock.h>
   57 #include <sys/malloc.h>
   58 #include <sys/mbuf.h>
   59 #include <sys/mutex.h>
   60 #include <sys/pioctl.h>
   61 #include <sys/proc.h>
   62 #include <sys/sf_buf.h>
   63 #include <sys/smp.h>
   64 #include <sys/sysctl.h>
   65 #include <sys/unistd.h>
   66 #include <sys/vnode.h>
   67 #include <sys/vmmeter.h>
   68 
   69 #include <machine/cpu.h>
   70 #include <machine/md_var.h>
   71 #include <machine/pcb.h>
   72 
   73 #include <vm/vm.h>
   74 #include <vm/vm_extern.h>
   75 #include <vm/vm_kern.h>
   76 #include <vm/vm_page.h>
   77 #include <vm/vm_map.h>
   78 #include <vm/vm_param.h>
   79 
   80 #include <amd64/isa/isa.h>
   81 
   82 static void     cpu_reset_real(void);
   83 #ifdef SMP
   84 static void     cpu_reset_proxy(void);
   85 static u_int    cpu_reset_proxyid;
   86 static volatile u_int   cpu_reset_proxy_active;
   87 #endif
   88 
   89 /*
   90  * Finish a fork operation, with process p2 nearly set up.
   91  * Copy and update the pcb, set up the stack so that the child
   92  * ready to run and return to user mode.
   93  */
   94 void
   95 cpu_fork(td1, p2, td2, flags)
   96         register struct thread *td1;
   97         register struct proc *p2;
   98         struct thread *td2;
   99         int flags;
  100 {
  101         register struct proc *p1;
  102         struct pcb *pcb2;
  103         struct mdproc *mdp2;
  104 
  105         p1 = td1->td_proc;
  106         if ((flags & RFPROC) == 0)
  107                 return;
  108 
  109         /* Ensure that p1's pcb is up to date. */
  110         fpuexit(td1);
  111 
  112         /* Point the pcb to the top of the stack */
  113         pcb2 = (struct pcb *)(td2->td_kstack +
  114             td2->td_kstack_pages * PAGE_SIZE) - 1;
  115         td2->td_pcb = pcb2;
  116 
  117         /* Copy p1's pcb */
  118         bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
  119 
  120         /* Point mdproc and then copy over td1's contents */
  121         mdp2 = &p2->p_md;
  122         bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
  123 
  124         /*
  125          * Create a new fresh stack for the new process.
  126          * Copy the trap frame for the return to user mode as if from a
  127          * syscall.  This copies most of the user mode register values.
  128          */
  129         td2->td_frame = (struct trapframe *)td2->td_pcb - 1;
  130         bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
  131 
  132         td2->td_frame->tf_rax = 0;              /* Child returns zero */
  133         td2->td_frame->tf_rflags &= ~PSL_C;     /* success */
  134         td2->td_frame->tf_rdx = 1;
  135 
  136         /*
  137          * If the parent process has the trap bit set (i.e. a debugger had
  138          * single stepped the process to the system call), we need to clear
  139          * the trap flag from the new frame unless the debugger had set PF_FORK
  140          * on the parent.  Otherwise, the child will receive a (likely
  141          * unexpected) SIGTRAP when it executes the first instruction after
  142          * returning  to userland.
  143          */
  144         if ((p1->p_pfsflags & PF_FORK) == 0)
  145                 td2->td_frame->tf_rflags &= ~PSL_T;
  146 
  147         /*
  148          * Set registers for trampoline to user mode.  Leave space for the
  149          * return address on stack.  These are the kernel mode register values.
  150          */
  151         pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pml4);
  152         pcb2->pcb_r12 = (register_t)fork_return;        /* fork_trampoline argument */
  153         pcb2->pcb_rbp = 0;
  154         pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *);
  155         pcb2->pcb_rbx = (register_t)td2;                /* fork_trampoline argument */
  156         pcb2->pcb_rip = (register_t)fork_trampoline;
  157         pcb2->pcb_rflags = td2->td_frame->tf_rflags & ~PSL_I; /* ints disabled */
  158         /*-
  159          * pcb2->pcb_dr*:       cloned above.
  160          * pcb2->pcb_savefpu:   cloned above.
  161          * pcb2->pcb_flags:     cloned above.
  162          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  163          * pcb2->pcb_[fg]sbase: cloned above
  164          */
  165 
  166         /*
  167          * Now, cpu_switch() can schedule the new process.
  168          * pcb_rsp is loaded pointing to the cpu_switch() stack frame
  169          * containing the return address when exiting cpu_switch.
  170          * This will normally be to fork_trampoline(), which will have
  171          * %ebx loaded with the new proc's pointer.  fork_trampoline()
  172          * will set up a stack to call fork_return(p, frame); to complete
  173          * the return to user-mode.
  174          */
  175 }
  176 
  177 /*
  178  * Intercept the return address from a freshly forked process that has NOT
  179  * been scheduled yet.
  180  *
  181  * This is needed to make kernel threads stay in kernel mode.
  182  */
  183 void
  184 cpu_set_fork_handler(td, func, arg)
  185         struct thread *td;
  186         void (*func)(void *);
  187         void *arg;
  188 {
  189         /*
  190          * Note that the trap frame follows the args, so the function
  191          * is really called like this:  func(arg, frame);
  192          */
  193         td->td_pcb->pcb_r12 = (long) func;      /* function */
  194         td->td_pcb->pcb_rbx = (long) arg;       /* first arg */
  195 }
  196 
  197 void
  198 cpu_exit(struct thread *td)
  199 {
  200 }
  201 
  202 void
  203 cpu_thread_exit(struct thread *td)
  204 {
  205         struct pcb *pcb = td->td_pcb;
  206 
  207         if (td == PCPU_GET(fpcurthread))
  208                 fpudrop();
  209         if (pcb->pcb_flags & PCB_DBREGS) {
  210                 /* disable all hardware breakpoints */
  211                 reset_dbregs();
  212                 pcb->pcb_flags &= ~PCB_DBREGS;
  213         }
  214 }
  215 
  216 void
  217 cpu_thread_clean(struct thread *td)
  218 {
  219 }
  220 
  221 void
  222 cpu_thread_swapin(struct thread *td)
  223 {
  224 }
  225 
  226 void
  227 cpu_thread_swapout(struct thread *td)
  228 {
  229 }
  230 
  231 void
  232 cpu_thread_setup(struct thread *td)
  233 {
  234 
  235         td->td_pcb = (struct pcb *)(td->td_kstack +
  236             td->td_kstack_pages * PAGE_SIZE) - 1;
  237         td->td_frame = (struct trapframe *)td->td_pcb - 1;
  238 }
  239 
  240 /*
  241  * Initialize machine state (pcb and trap frame) for a new thread about to
  242  * upcall. Put enough state in the new thread's PCB to get it to go back 
  243  * userret(), where we can intercept it again to set the return (upcall)
  244  * Address and stack, along with those from upcals that are from other sources
  245  * such as those generated in thread_userret() itself.
  246  */
  247 void
  248 cpu_set_upcall(struct thread *td, struct thread *td0)
  249 {
  250         struct pcb *pcb2;
  251 
  252         /* Point the pcb to the top of the stack. */
  253         pcb2 = td->td_pcb;
  254 
  255         /*
  256          * Copy the upcall pcb.  This loads kernel regs.
  257          * Those not loaded individually below get their default
  258          * values here.
  259          *
  260          * XXXKSE It might be a good idea to simply skip this as
  261          * the values of the other registers may be unimportant.
  262          * This would remove any requirement for knowing the KSE
  263          * at this time (see the matching comment below for
  264          * more analysis) (need a good safe default).
  265          */
  266         bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
  267         pcb2->pcb_flags &= ~PCB_FPUINITDONE;
  268 
  269         /*
  270          * Create a new fresh stack for the new thread.
  271          * Don't forget to set this stack value into whatever supplies
  272          * the address for the fault handlers.
  273          * The contexts are filled in at the time we actually DO the
  274          * upcall as only then do we know which KSE we got.
  275          */
  276         bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
  277 
  278         /*
  279          * Set registers for trampoline to user mode.  Leave space for the
  280          * return address on stack.  These are the kernel mode register values.
  281          */
  282         pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pml4);
  283         pcb2->pcb_r12 = (register_t)fork_return;            /* trampoline arg */
  284         pcb2->pcb_rbp = 0;
  285         pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *);      /* trampoline arg */
  286         pcb2->pcb_rbx = (register_t)td;                     /* trampoline arg */
  287         pcb2->pcb_rip = (register_t)fork_trampoline;
  288         pcb2->pcb_rflags = PSL_KERNEL; /* ints disabled */
  289         /*
  290          * If we didn't copy the pcb, we'd need to do the following registers:
  291          * pcb2->pcb_dr*:       cloned above.
  292          * pcb2->pcb_savefpu:   cloned above.
  293          * pcb2->pcb_rflags:    cloned above.
  294          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  295          * pcb2->pcb_[fg]sbase: cloned above
  296          */
  297 }
  298 
  299 /*
  300  * Set that machine state for performing an upcall that has to
  301  * be done in thread_userret() so that those upcalls generated
  302  * in thread_userret() itself can be done as well.
  303  */
  304 void
  305 cpu_set_upcall_kse(struct thread *td, struct kse_upcall *ku)
  306 {
  307 
  308         /* 
  309          * Do any extra cleaning that needs to be done.
  310          * The thread may have optional components
  311          * that are not present in a fresh thread.
  312          * This may be a recycled thread so make it look
  313          * as though it's newly allocated.
  314          */
  315         cpu_thread_clean(td);
  316 
  317         /*
  318          * Set the trap frame to point at the beginning of the uts
  319          * function.
  320          */
  321         td->td_frame->tf_rbp = 0; 
  322         td->td_frame->tf_rsp =
  323             ((register_t)ku->ku_stack.ss_sp + ku->ku_stack.ss_size) & ~0x0f;
  324         td->td_frame->tf_rsp -= 8;
  325         td->td_frame->tf_rbp = 0;
  326         td->td_frame->tf_rip = (register_t)ku->ku_func;
  327 
  328         /*
  329          * Pass the address of the mailbox for this kse to the uts
  330          * function as a parameter on the stack.
  331          */
  332         td->td_frame->tf_rdi = (register_t)ku->ku_mailbox;
  333 }
  334 
  335 #ifdef SMP
  336 static void
  337 cpu_reset_proxy()
  338 {
  339 
  340         cpu_reset_proxy_active = 1;
  341         while (cpu_reset_proxy_active == 1)
  342                 ;       /* Wait for other cpu to see that we've started */
  343         stop_cpus((1<<cpu_reset_proxyid));
  344         printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
  345         DELAY(1000000);
  346         cpu_reset_real();
  347 }
  348 #endif
  349 
  350 void
  351 cpu_reset()
  352 {
  353 #ifdef SMP
  354         u_int cnt, map;
  355 
  356         if (smp_active) {
  357                 map = PCPU_GET(other_cpus) & ~stopped_cpus;
  358                 if (map != 0) {
  359                         printf("cpu_reset: Stopping other CPUs\n");
  360                         stop_cpus(map);
  361                 }
  362 
  363                 if (PCPU_GET(cpuid) != 0) {
  364                         cpu_reset_proxyid = PCPU_GET(cpuid);
  365                         cpustop_restartfunc = cpu_reset_proxy;
  366                         cpu_reset_proxy_active = 0;
  367                         printf("cpu_reset: Restarting BSP\n");
  368                         started_cpus = (1<<0);          /* Restart CPU #0 */
  369 
  370                         cnt = 0;
  371                         while (cpu_reset_proxy_active == 0 && cnt < 10000000)
  372                                 cnt++;  /* Wait for BSP to announce restart */
  373                         if (cpu_reset_proxy_active == 0)
  374                                 printf("cpu_reset: Failed to restart BSP\n");
  375                         enable_intr();
  376                         cpu_reset_proxy_active = 2;
  377 
  378                         while (1);
  379                         /* NOTREACHED */
  380                 }
  381 
  382                 DELAY(1000000);
  383         }
  384 #endif
  385         cpu_reset_real();
  386         /* NOTREACHED */
  387 }
  388 
  389 static void
  390 cpu_reset_real()
  391 {
  392 
  393         /*
  394          * Attempt to do a CPU reset via the keyboard controller,
  395          * do not turn off GateA20, as any machine that fails
  396          * to do the reset here would then end up in no man's land.
  397          */
  398         outb(IO_KBD + 4, 0xFE);
  399         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  400         printf("Keyboard reset did not work, attempting CPU shutdown\n");
  401         DELAY(1000000); /* wait 1 sec for printf to complete */
  402 
  403         /* Force a shutdown by unmapping entire address space. */
  404         bzero((caddr_t)PML4map, PAGE_SIZE);
  405 
  406         /* "good night, sweet prince .... <THUNK!>" */
  407         invltlb();
  408         /* NOTREACHED */
  409         while(1);
  410 }
  411 
  412 /*
  413  * Allocate an sf_buf for the given vm_page.  On this machine, however, there
  414  * is no sf_buf object.  Instead, an opaque pointer to the given vm_page is
  415  * returned.
  416  */
  417 struct sf_buf *
  418 sf_buf_alloc(struct vm_page *m, int pri)
  419 {
  420 
  421         return ((struct sf_buf *)m);
  422 }
  423 
  424 /*
  425  * Free the sf_buf.  In fact, do nothing because there are no resources
  426  * associated with the sf_buf.
  427  */
  428 void
  429 sf_buf_free(struct sf_buf *sf)
  430 {
  431 }
  432 
  433 /*
  434  * Software interrupt handler for queued VM system processing.
  435  */   
  436 void  
  437 swi_vm(void *dummy) 
  438 {     
  439         if (busdma_swi_pending != 0)
  440                 busdma_swi();
  441 }
  442 
  443 /*
  444  * Tell whether this address is in some physical memory region.
  445  * Currently used by the kernel coredump code in order to avoid
  446  * dumping the ``ISA memory hole'' which could cause indefinite hangs,
  447  * or other unpredictable behaviour.
  448  */
  449 
  450 int
  451 is_physical_memory(vm_paddr_t addr)
  452 {
  453 
  454 #ifdef DEV_ISA
  455         /* The ISA ``memory hole''. */
  456         if (addr >= 0xa0000 && addr < 0x100000)
  457                 return 0;
  458 #endif
  459 
  460         /*
  461          * stuff other tests for known memory-mapped devices (PCI?)
  462          * here
  463          */
  464 
  465         return 1;
  466 }

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