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("$FreeBSD$");
   45 
   46 #include "opt_isa.h"
   47 #include "opt_cpu.h"
   48 #include "opt_compat.h"
   49 
   50 #include <sys/param.h>
   51 #include <sys/systm.h>
   52 #include <sys/bio.h>
   53 #include <sys/buf.h>
   54 #include <sys/kse.h>
   55 #include <sys/kernel.h>
   56 #include <sys/ktr.h>
   57 #include <sys/lock.h>
   58 #include <sys/malloc.h>
   59 #include <sys/mbuf.h>
   60 #include <sys/mutex.h>
   61 #include <sys/pioctl.h>
   62 #include <sys/proc.h>
   63 #include <sys/sf_buf.h>
   64 #include <sys/smp.h>
   65 #include <sys/sysctl.h>
   66 #include <sys/unistd.h>
   67 #include <sys/vnode.h>
   68 #include <sys/vmmeter.h>
   69 
   70 #include <machine/cpu.h>
   71 #include <machine/md_var.h>
   72 #include <machine/pcb.h>
   73 #include <machine/specialreg.h>
   74 
   75 #include <vm/vm.h>
   76 #include <vm/vm_extern.h>
   77 #include <vm/vm_kern.h>
   78 #include <vm/vm_page.h>
   79 #include <vm/vm_map.h>
   80 #include <vm/vm_param.h>
   81 
   82 #include <amd64/isa/isa.h>
   83 
   84 #ifdef COMPAT_IA32
   85 
   86 extern struct sysentvec ia32_freebsd_sysvec;
   87 
   88 #endif
   89 
   90 static void     cpu_reset_real(void);
   91 #ifdef SMP
   92 static void     cpu_reset_proxy(void);
   93 static u_int    cpu_reset_proxyid;
   94 static volatile u_int   cpu_reset_proxy_active;
   95 #endif
   96 
   97 /*
   98  * Finish a fork operation, with process p2 nearly set up.
   99  * Copy and update the pcb, set up the stack so that the child
  100  * ready to run and return to user mode.
  101  */
  102 void
  103 cpu_fork(td1, p2, td2, flags)
  104         register struct thread *td1;
  105         register struct proc *p2;
  106         struct thread *td2;
  107         int flags;
  108 {
  109         register struct proc *p1;
  110         struct pcb *pcb2;
  111         struct mdproc *mdp2;
  112         pmap_t pmap2;
  113 
  114         p1 = td1->td_proc;
  115         if ((flags & RFPROC) == 0)
  116                 return;
  117 
  118         /* Ensure that p1's pcb is up to date. */
  119         fpuexit(td1);
  120 
  121         /* Point the pcb to the top of the stack */
  122         pcb2 = (struct pcb *)(td2->td_kstack +
  123             td2->td_kstack_pages * PAGE_SIZE) - 1;
  124         td2->td_pcb = pcb2;
  125 
  126         /* Copy p1's pcb */
  127         bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
  128 
  129         /* Point mdproc and then copy over td1's contents */
  130         mdp2 = &p2->p_md;
  131         bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
  132 
  133         /*
  134          * Create a new fresh stack for the new process.
  135          * Copy the trap frame for the return to user mode as if from a
  136          * syscall.  This copies most of the user mode register values.
  137          */
  138         td2->td_frame = (struct trapframe *)td2->td_pcb - 1;
  139         bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
  140 
  141         td2->td_frame->tf_rax = 0;              /* Child returns zero */
  142         td2->td_frame->tf_rflags &= ~PSL_C;     /* success */
  143         td2->td_frame->tf_rdx = 1;
  144 
  145         /*
  146          * If the parent process has the trap bit set (i.e. a debugger had
  147          * single stepped the process to the system call), we need to clear
  148          * the trap flag from the new frame unless the debugger had set PF_FORK
  149          * on the parent.  Otherwise, the child will receive a (likely
  150          * unexpected) SIGTRAP when it executes the first instruction after
  151          * returning  to userland.
  152          */
  153         if ((p1->p_pfsflags & PF_FORK) == 0)
  154                 td2->td_frame->tf_rflags &= ~PSL_T;
  155 
  156         /*
  157          * Set registers for trampoline to user mode.  Leave space for the
  158          * return address on stack.  These are the kernel mode register values.
  159          */
  160         pmap2 = vmspace_pmap(p2->p_vmspace);
  161         pcb2->pcb_cr3 = DMAP_TO_PHYS((vm_offset_t)pmap2->pm_pml4);
  162         pcb2->pcb_r12 = (register_t)fork_return;        /* fork_trampoline argument */
  163         pcb2->pcb_rbp = 0;
  164         pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *);
  165         pcb2->pcb_rbx = (register_t)td2;                /* fork_trampoline argument */
  166         pcb2->pcb_rip = (register_t)fork_trampoline;
  167         /*-
  168          * pcb2->pcb_dr*:       cloned above.
  169          * pcb2->pcb_savefpu:   cloned above.
  170          * pcb2->pcb_flags:     cloned above.
  171          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  172          * pcb2->pcb_[fg]sbase: cloned above
  173          */
  174 
  175         /* Setup to release spin count in fork_exit(). */
  176         td2->td_md.md_spinlock_count = 1;
  177         td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  178 
  179         /*
  180          * Now, cpu_switch() can schedule the new process.
  181          * pcb_rsp is loaded pointing to the cpu_switch() stack frame
  182          * containing the return address when exiting cpu_switch.
  183          * This will normally be to fork_trampoline(), which will have
  184          * %ebx loaded with the new proc's pointer.  fork_trampoline()
  185          * will set up a stack to call fork_return(p, frame); to complete
  186          * the return to user-mode.
  187          */
  188 }
  189 
  190 /*
  191  * Intercept the return address from a freshly forked process that has NOT
  192  * been scheduled yet.
  193  *
  194  * This is needed to make kernel threads stay in kernel mode.
  195  */
  196 void
  197 cpu_set_fork_handler(td, func, arg)
  198         struct thread *td;
  199         void (*func)(void *);
  200         void *arg;
  201 {
  202         /*
  203          * Note that the trap frame follows the args, so the function
  204          * is really called like this:  func(arg, frame);
  205          */
  206         td->td_pcb->pcb_r12 = (long) func;      /* function */
  207         td->td_pcb->pcb_rbx = (long) arg;       /* first arg */
  208 }
  209 
  210 void
  211 cpu_exit(struct thread *td)
  212 {
  213 }
  214 
  215 void
  216 cpu_thread_exit(struct thread *td)
  217 {
  218 
  219         if (td == PCPU_GET(fpcurthread))
  220                 fpudrop();
  221 
  222         /* Disable any hardware breakpoints. */
  223         if (td->td_pcb->pcb_flags & PCB_DBREGS) {
  224                 reset_dbregs();
  225                 td->td_pcb->pcb_flags &= ~PCB_DBREGS;
  226         }
  227 }
  228 
  229 void
  230 cpu_thread_clean(struct thread *td)
  231 {
  232 }
  233 
  234 void
  235 cpu_thread_swapin(struct thread *td)
  236 {
  237 }
  238 
  239 void
  240 cpu_thread_swapout(struct thread *td)
  241 {
  242 }
  243 
  244 void
  245 cpu_thread_alloc(struct thread *td)
  246 {
  247 
  248         td->td_pcb = (struct pcb *)(td->td_kstack +
  249             td->td_kstack_pages * PAGE_SIZE) - 1;
  250         td->td_frame = (struct trapframe *)td->td_pcb - 1;
  251 }
  252 
  253 void
  254 cpu_thread_free(struct thread *td)
  255 {
  256 }
  257 
  258 /*
  259  * Initialize machine state (pcb and trap frame) for a new thread about to
  260  * upcall. Put enough state in the new thread's PCB to get it to go back 
  261  * userret(), where we can intercept it again to set the return (upcall)
  262  * Address and stack, along with those from upcals that are from other sources
  263  * such as those generated in thread_userret() itself.
  264  */
  265 void
  266 cpu_set_upcall(struct thread *td, struct thread *td0)
  267 {
  268         struct pcb *pcb2;
  269 
  270         /* Point the pcb to the top of the stack. */
  271         pcb2 = td->td_pcb;
  272 
  273         /*
  274          * Copy the upcall pcb.  This loads kernel regs.
  275          * Those not loaded individually below get their default
  276          * values here.
  277          *
  278          * XXXKSE It might be a good idea to simply skip this as
  279          * the values of the other registers may be unimportant.
  280          * This would remove any requirement for knowing the KSE
  281          * at this time (see the matching comment below for
  282          * more analysis) (need a good safe default).
  283          */
  284         bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
  285         pcb2->pcb_flags &= ~PCB_FPUINITDONE;
  286 
  287         /*
  288          * Create a new fresh stack for the new thread.
  289          * Don't forget to set this stack value into whatever supplies
  290          * the address for the fault handlers.
  291          * The contexts are filled in at the time we actually DO the
  292          * upcall as only then do we know which KSE we got.
  293          */
  294         bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
  295 
  296         /*
  297          * Set registers for trampoline to user mode.  Leave space for the
  298          * return address on stack.  These are the kernel mode register values.
  299          */
  300         pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pml4);
  301         pcb2->pcb_r12 = (register_t)fork_return;            /* trampoline arg */
  302         pcb2->pcb_rbp = 0;
  303         pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *);      /* trampoline arg */
  304         pcb2->pcb_rbx = (register_t)td;                     /* trampoline arg */
  305         pcb2->pcb_rip = (register_t)fork_trampoline;
  306         /*
  307          * If we didn't copy the pcb, we'd need to do the following registers:
  308          * pcb2->pcb_dr*:       cloned above.
  309          * pcb2->pcb_savefpu:   cloned above.
  310          * pcb2->pcb_onfault:   cloned above (always NULL here?).
  311          * pcb2->pcb_[fg]sbase: cloned above
  312          */
  313 
  314         /* Setup to release spin count in fork_exit(). */
  315         td->td_md.md_spinlock_count = 1;
  316         td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
  317 }
  318 
  319 /*
  320  * Set that machine state for performing an upcall that has to
  321  * be done in thread_userret() so that those upcalls generated
  322  * in thread_userret() itself can be done as well.
  323  */
  324 void
  325 cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
  326         stack_t *stack)
  327 {
  328 
  329         /* 
  330          * Do any extra cleaning that needs to be done.
  331          * The thread may have optional components
  332          * that are not present in a fresh thread.
  333          * This may be a recycled thread so make it look
  334          * as though it's newly allocated.
  335          */
  336         cpu_thread_clean(td);
  337 
  338 #ifdef COMPAT_IA32
  339         if (td->td_proc->p_sysent == &ia32_freebsd_sysvec) {
  340                 /*
  341                  * Set the trap frame to point at the beginning of the uts
  342                  * function.
  343                  */
  344                 td->td_frame->tf_rbp = 0;
  345                 td->td_frame->tf_rsp =
  346                    (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
  347                 td->td_frame->tf_rip = (uintptr_t)entry;
  348 
  349                 /*
  350                  * Pass the address of the mailbox for this kse to the uts
  351                  * function as a parameter on the stack.
  352                  */
  353                 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)),
  354                     (uint32_t)(uintptr_t)arg);
  355 
  356                 return;
  357         }
  358 #endif
  359 
  360         /*
  361          * Set the trap frame to point at the beginning of the uts
  362          * function.
  363          */
  364         td->td_frame->tf_rbp = 0;
  365         td->td_frame->tf_rsp =
  366             ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f;
  367         td->td_frame->tf_rsp -= 8;
  368         td->td_frame->tf_rip = (register_t)entry;
  369 
  370         /*
  371          * Pass the address of the mailbox for this kse to the uts
  372          * function as a parameter on the stack.
  373          */
  374         td->td_frame->tf_rdi = (register_t)arg;
  375 }
  376 
  377 int
  378 cpu_set_user_tls(struct thread *td, void *tls_base)
  379 {
  380 
  381         if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS)
  382                 return (EINVAL);
  383 
  384 #ifdef COMPAT_IA32
  385         if (td->td_proc->p_sysent == &ia32_freebsd_sysvec) {
  386                 if (td == curthread) {
  387                         critical_enter();
  388                         td->td_pcb->pcb_gsbase = (register_t)tls_base;
  389                         wrmsr(MSR_KGSBASE, td->td_pcb->pcb_gsbase);
  390                         critical_exit();
  391                 } else {
  392                         td->td_pcb->pcb_gsbase = (register_t)tls_base;
  393                 }
  394                 return (0);
  395         }
  396 #endif
  397         if (td == curthread) {
  398                 critical_enter();
  399                 td->td_pcb->pcb_fsbase = (register_t)tls_base;
  400                 wrmsr(MSR_FSBASE, td->td_pcb->pcb_fsbase);
  401                 critical_exit();
  402         } else {
  403                 td->td_pcb->pcb_fsbase = (register_t)tls_base;
  404         }
  405         return (0);
  406 }
  407 
  408 #ifdef SMP
  409 static void
  410 cpu_reset_proxy()
  411 {
  412 
  413         cpu_reset_proxy_active = 1;
  414         while (cpu_reset_proxy_active == 1)
  415                 ;       /* Wait for other cpu to see that we've started */
  416         stop_cpus((1<<cpu_reset_proxyid));
  417         printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
  418         DELAY(1000000);
  419         cpu_reset_real();
  420 }
  421 #endif
  422 
  423 void
  424 cpu_reset()
  425 {
  426 #ifdef SMP
  427         u_int cnt, map;
  428 
  429         if (smp_active) {
  430                 map = PCPU_GET(other_cpus) & ~stopped_cpus;
  431                 if (map != 0) {
  432                         printf("cpu_reset: Stopping other CPUs\n");
  433                         stop_cpus(map);
  434                 }
  435 
  436                 if (PCPU_GET(cpuid) != 0) {
  437                         cpu_reset_proxyid = PCPU_GET(cpuid);
  438                         cpustop_restartfunc = cpu_reset_proxy;
  439                         cpu_reset_proxy_active = 0;
  440                         printf("cpu_reset: Restarting BSP\n");
  441 
  442                         /* Restart CPU #0. */
  443                         atomic_store_rel_int(&started_cpus, 1 << 0);
  444 
  445                         cnt = 0;
  446                         while (cpu_reset_proxy_active == 0 && cnt < 10000000)
  447                                 cnt++;  /* Wait for BSP to announce restart */
  448                         if (cpu_reset_proxy_active == 0)
  449                                 printf("cpu_reset: Failed to restart BSP\n");
  450                         enable_intr();
  451                         cpu_reset_proxy_active = 2;
  452 
  453                         while (1);
  454                         /* NOTREACHED */
  455                 }
  456 
  457                 DELAY(1000000);
  458         }
  459 #endif
  460         cpu_reset_real();
  461         /* NOTREACHED */
  462 }
  463 
  464 static void
  465 cpu_reset_real()
  466 {
  467         struct region_descriptor null_idt;
  468         int b;
  469 
  470         disable_intr();
  471 
  472         /*
  473          * Attempt to do a CPU reset via the keyboard controller,
  474          * do not turn off GateA20, as any machine that fails
  475          * to do the reset here would then end up in no man's land.
  476          */
  477         outb(IO_KBD + 4, 0xFE);
  478         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  479 
  480         /*
  481          * Attempt to force a reset via the Reset Control register at
  482          * I/O port 0xcf9.  Bit 2 forces a system reset when it
  483          * transitions from 0 to 1.  Bit 1 selects the type of reset
  484          * to attempt: 0 selects a "soft" reset, and 1 selects a
  485          * "hard" reset.  We try a "hard" reset.  The first write sets
  486          * bit 1 to select a "hard" reset and clears bit 2.  The
  487          * second write forces a 0 -> 1 transition in bit 2 to trigger
  488          * a reset.
  489          */
  490         outb(0xcf9, 0x2);
  491         outb(0xcf9, 0x6);
  492         DELAY(500000);  /* wait 0.5 sec to see if that did it */
  493 
  494         /*
  495          * Attempt to force a reset via the Fast A20 and Init register
  496          * at I/O port 0x92.  Bit 1 serves as an alternate A20 gate.
  497          * Bit 0 asserts INIT# when set to 1.  We are careful to only
  498          * preserve bit 1 while setting bit 0.  We also must clear bit
  499          * 0 before setting it if it isn't already clear.
  500          */
  501         b = inb(0x92);
  502         if (b != 0xff) {
  503                 if ((b & 0x1) != 0)
  504                         outb(0x92, b & 0xfe);
  505                 outb(0x92, b | 0x1);
  506                 DELAY(500000);  /* wait 0.5 sec to see if that did it */
  507         }
  508 
  509         printf("No known reset method worked, attempting CPU shutdown\n");
  510         DELAY(1000000); /* wait 1 sec for printf to complete */
  511 
  512         /* Wipe the IDT. */
  513         null_idt.rd_limit = 0;
  514         null_idt.rd_base = 0;
  515         lidt(&null_idt);
  516 
  517         /* "good night, sweet prince .... <THUNK!>" */
  518         breakpoint();
  519 
  520         /* NOTREACHED */
  521         while(1);
  522 }
  523 
  524 /*
  525  * Allocate an sf_buf for the given vm_page.  On this machine, however, there
  526  * is no sf_buf object.  Instead, an opaque pointer to the given vm_page is
  527  * returned.
  528  */
  529 struct sf_buf *
  530 sf_buf_alloc(struct vm_page *m, int pri)
  531 {
  532 
  533         return ((struct sf_buf *)m);
  534 }
  535 
  536 /*
  537  * Free the sf_buf.  In fact, do nothing because there are no resources
  538  * associated with the sf_buf.
  539  */
  540 void
  541 sf_buf_free(struct sf_buf *sf)
  542 {
  543 }
  544 
  545 /*
  546  * Software interrupt handler for queued VM system processing.
  547  */   
  548 void  
  549 swi_vm(void *dummy) 
  550 {     
  551         if (busdma_swi_pending != 0)
  552                 busdma_swi();
  553 }
  554 
  555 /*
  556  * Tell whether this address is in some physical memory region.
  557  * Currently used by the kernel coredump code in order to avoid
  558  * dumping the ``ISA memory hole'' which could cause indefinite hangs,
  559  * or other unpredictable behaviour.
  560  */
  561 
  562 int
  563 is_physical_memory(vm_paddr_t addr)
  564 {
  565 
  566 #ifdef DEV_ISA
  567         /* The ISA ``memory hole''. */
  568         if (addr >= 0xa0000 && addr < 0x100000)
  569                 return 0;
  570 #endif
  571 
  572         /*
  573          * stuff other tests for known memory-mapped devices (PCI?)
  574          * here
  575          */
  576 
  577         return 1;
  578 }

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