FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/vm_machdep.c

     /*-
      * Copyright (c) 1982, 1986 The Regents of the University of California.
      * Copyright (c) 1989, 1990 William Jolitz
      * Copyright (c) 1994 John Dyson
      * All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * the Systems Programming Group of the University of Utah Computer
      * Science Department, and William Jolitz.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      from: @(#)vm_machdep.c  7.3 (Berkeley) 5/13/91
     *      Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
     * $FreeBSD: releng/5.0/sys/i386/i386/vm_machdep.c 107719 2002-12-10 02:33:45Z julian $
     */
    
    #include "opt_npx.h"
    #ifdef PC98
    #include "opt_pc98.h"
    #endif
    #include "opt_reset.h"
    #include "opt_isa.h"
    #include "opt_kstack_pages.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/malloc.h>
    #include <sys/proc.h>
    #include <sys/kse.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/vnode.h>
    #include <sys/vmmeter.h>
    #include <sys/kernel.h>
    #include <sys/ktr.h>
    #include <sys/mutex.h>
    #include <sys/smp.h>
    #include <sys/sysctl.h>
    #include <sys/unistd.h>
    
    #include <machine/cpu.h>
    #include <machine/md_var.h>
    #include <machine/pcb.h>
    #include <machine/pcb_ext.h>
    #include <machine/vm86.h>
    
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <sys/lock.h>
    #include <vm/vm_kern.h>
    #include <vm/vm_page.h>
    #include <vm/vm_map.h>
    #include <vm/vm_extern.h>
    
    #include <sys/user.h>
    
    #ifdef PC98
    #include <pc98/pc98/pc98.h>
    #else
    #include <i386/isa/isa.h>
    #endif
    
    static void     cpu_reset_real(void);
    #ifdef SMP
    static void     cpu_reset_proxy(void);
    static u_int    cpu_reset_proxyid;
    static volatile u_int   cpu_reset_proxy_active;
    #endif
    extern int      _ucodesel, _udatasel;
    
    /*
     * quick version of vm_fault
    */
   int
   vm_fault_quick(v, prot)
           caddr_t v;
           int prot;
   {
           int r;
   
           if (prot & VM_PROT_WRITE)
                   r = subyte(v, fubyte(v));
           else
                   r = fubyte(v);
           return(r);
   }
   
   /*
    * Finish a fork operation, with process p2 nearly set up.
    * Copy and update the pcb, set up the stack so that the child
    * ready to run and return to user mode.
    */
   void
   cpu_fork(td1, p2, td2, flags)
           register struct thread *td1;
           register struct proc *p2;
           struct thread *td2;
           int flags;
   {
           register struct proc *p1;
           struct pcb *pcb2;
           struct mdproc *mdp2;
   #ifdef DEV_NPX
           register_t savecrit;
   #endif
   
           p1 = td1->td_proc;
           if ((flags & RFPROC) == 0) {
                   if ((flags & RFMEM) == 0) {
                           /* unshare user LDT */
                           struct mdproc *mdp1 = &p1->p_md;
                           struct proc_ldt *pldt = mdp1->md_ldt;
                           if (pldt && pldt->ldt_refcnt > 1) {
                                   pldt = user_ldt_alloc(mdp1, pldt->ldt_len);
                                   if (pldt == NULL)
                                           panic("could not copy LDT");
                                   mdp1->md_ldt = pldt;
                                   set_user_ldt(mdp1);
                                   user_ldt_free(td1);
                           }
                   }
                   return;
           }
   
           /* Ensure that p1's pcb is up to date. */
   #ifdef DEV_NPX
           if (td1 == curthread)
                   td1->td_pcb->pcb_gs = rgs();
           savecrit = intr_disable();
           if (PCPU_GET(fpcurthread) == td1)
                   npxsave(&td1->td_pcb->pcb_save);
           intr_restore(savecrit);
   #endif
   
           /* Point the pcb to the top of the stack */
           pcb2 = (struct pcb *)(td2->td_kstack + KSTACK_PAGES * PAGE_SIZE) - 1;
           td2->td_pcb = pcb2;
   
           /* Copy p1's pcb */
           bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
   
           /* Point mdproc and then copy over td1's contents */
           mdp2 = &p2->p_md;
           bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
   
           /*
            * Create a new fresh stack for the new process.
            * Copy the trap frame for the return to user mode as if from a
            * syscall.  This copies most of the user mode register values.
            * The -16 is so we can expand the trapframe if we go to vm86.
            */
           td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
           bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
   
           td2->td_frame->tf_eax = 0;              /* Child returns zero */
           td2->td_frame->tf_eflags &= ~PSL_C;     /* success */
           td2->td_frame->tf_edx = 1;
   
           /*
            * Set registers for trampoline to user mode.  Leave space for the
            * return address on stack.  These are the kernel mode register values.
            */
           pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
           pcb2->pcb_edi = 0;
           pcb2->pcb_esi = (int)fork_return;       /* fork_trampoline argument */
           pcb2->pcb_ebp = 0;
           pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
           pcb2->pcb_ebx = (int)td2;               /* fork_trampoline argument */
           pcb2->pcb_eip = (int)fork_trampoline;
           pcb2->pcb_psl = td2->td_frame->tf_eflags & ~PSL_I; /* ints disabled */
           /*-
            * pcb2->pcb_dr*:       cloned above.
            * pcb2->pcb_savefpu:   cloned above.
            * pcb2->pcb_flags:     cloned above.
            * pcb2->pcb_onfault:   cloned above (always NULL here?).
            * pcb2->pcb_gs:        cloned above.
            * pcb2->pcb_ext:       cleared below.
            */
   
           /*
            * XXX don't copy the i/o pages.  this should probably be fixed.
            */
           pcb2->pcb_ext = 0;
   
           /* Copy the LDT, if necessary. */
           mtx_lock_spin(&sched_lock);
           if (mdp2->md_ldt != 0) {
                   if (flags & RFMEM) {
                           mdp2->md_ldt->ldt_refcnt++;
                   } else {
                           mdp2->md_ldt = user_ldt_alloc(mdp2,
                               mdp2->md_ldt->ldt_len);
                           if (mdp2->md_ldt == NULL)
                                   panic("could not copy LDT");
                   }
           }
           mtx_unlock_spin(&sched_lock);
   
           /*
            * Now, cpu_switch() can schedule the new process.
            * pcb_esp is loaded pointing to the cpu_switch() stack frame
            * containing the return address when exiting cpu_switch.
            * This will normally be to fork_trampoline(), which will have
            * %ebx loaded with the new proc's pointer.  fork_trampoline()
            * will set up a stack to call fork_return(p, frame); to complete
            * the return to user-mode.
            */
   }
   
   /*
    * Intercept the return address from a freshly forked process that has NOT
    * been scheduled yet.
    *
    * This is needed to make kernel threads stay in kernel mode.
    */
   void
   cpu_set_fork_handler(td, func, arg)
           struct thread *td;
           void (*func)(void *);
           void *arg;
   {
           /*
            * Note that the trap frame follows the args, so the function
            * is really called like this:  func(arg, frame);
            */
           td->td_pcb->pcb_esi = (int) func;       /* function */
           td->td_pcb->pcb_ebx = (int) arg;        /* first arg */
   }
   
   void
   cpu_exit(struct thread *td)
   {
           struct mdproc *mdp;
   
           mdp = &td->td_proc->p_md;
           if (mdp->md_ldt)
                   user_ldt_free(td);
           reset_dbregs();
   }
   
   void
   cpu_thread_exit(struct thread *td)
   {
           struct pcb *pcb = td->td_pcb; 
   #ifdef DEV_NPX
           npxexit(td);
   #endif
           if (pcb->pcb_flags & PCB_DBREGS) {
                   /*
                    * disable all hardware breakpoints
                    */
                   reset_dbregs();
                   pcb->pcb_flags &= ~PCB_DBREGS;
           }
   }
   
   void
   cpu_thread_clean(struct thread *td)
   {
           struct pcb *pcb;
   
           pcb = td->td_pcb; 
           if (pcb->pcb_ext != 0) {
                   /* XXXKSE  XXXSMP  not SMP SAFE.. what locks do we have? */
                   /* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
                   /*
                    * XXX do we need to move the TSS off the allocated pages
                    * before freeing them?  (not done here)
                    */
                   mtx_lock(&Giant);
                   kmem_free(kernel_map, (vm_offset_t)pcb->pcb_ext,
                       ctob(IOPAGES + 1));
                   mtx_unlock(&Giant);
                   pcb->pcb_ext = 0;
           }
   }
   
   void
   cpu_sched_exit(td)
           register struct thread *td;
   {
   }
   
   void
   cpu_thread_setup(struct thread *td)
   {
   
           td->td_pcb =
                (struct pcb *)(td->td_kstack + KSTACK_PAGES * PAGE_SIZE) - 1;
           td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1;
   }
   
   /*
    * Initialize machine state (pcb and trap frame) for a new thread about to
    * upcall. Pu t enough state in the new thread's PCB to get it to go back 
    * userret(), where we can intercept it again to set the return (upcall)
    * Address and stack, along with those from upcals that are from other sources
    * such as those generated in thread_userret() itself.
    */
   void
   cpu_set_upcall(struct thread *td, void *pcb)
   {
           struct pcb *pcb2;
   
           td->td_flags |= TDF_UPCALLING;
   
           /* Point the pcb to the top of the stack. */
           pcb2 = td->td_pcb;
   
           /*
            * Copy the upcall pcb.  This loads kernel regs.
            * Those not loaded individually below get their default
            * values here.
            *
            * XXXKSE It might be a good idea to simply skip this as
            * the values of the other registers may be unimportant.
            * This would remove any requirement for knowing the KSE
            * at this time (see the matching comment below for
            * more analysis) (need a good safe default).
            */
           bcopy(pcb, pcb2, sizeof(*pcb2));
   
           /*
            * Create a new fresh stack for the new thread.
            * The -16 is so we can expand the trapframe if we go to vm86.
            * Don't forget to set this stack value into whatever supplies
            * the address for the fault handlers.
            * The contexts are filled in at the time we actually DO the
            * upcall as only then do we know which KSE we got.
            */
           td->td_frame = (struct trapframe *)((caddr_t)pcb2 - 16) - 1;
   
           /*
            * Set registers for trampoline to user mode.  Leave space for the
            * return address on stack.  These are the kernel mode register values.
            */
           pcb2->pcb_cr3 = vtophys(vmspace_pmap(td->td_proc->p_vmspace)->pm_pdir);
           pcb2->pcb_edi = 0;
           pcb2->pcb_esi = (int)fork_return;                   /* trampoline arg */
           pcb2->pcb_ebp = 0;
           pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
           pcb2->pcb_ebx = (int)td;                            /* trampoline arg */
           pcb2->pcb_eip = (int)fork_trampoline;
           pcb2->pcb_psl &= ~(PSL_I);      /* interrupts must be disabled */
           /*
            * If we didn't copy the pcb, we'd need to do the following registers:
            * pcb2->pcb_dr*:       cloned above.
            * pcb2->pcb_savefpu:   cloned above.
            * pcb2->pcb_flags:     cloned above.
            * pcb2->pcb_onfault:   cloned above (always NULL here?).
            * pcb2->pcb_gs:        cloned above.  XXXKSE ???
            * pcb2->pcb_ext:       cleared below.
            */
            pcb2->pcb_ext = NULL;
   }
   
   /*
    * Set that machine state for performing an upcall that has to
    * be done in thread_userret() so that those upcalls generated
    * in thread_userret() itself can be done as well.
    */
   void
   cpu_set_upcall_kse(struct thread *td, struct kse *ke)
   {
   
           /* 
            * Do any extra cleaning that needs to be done.
            * The thread may have optional components
            * that are not present in a fresh thread.
            * This may be a recycled thread so make it look
            * as though it's newly allocated.
            */
           cpu_thread_clean(td);
   
           /*
            * Set the trap frame to point at the beginning of the uts
            * function.
            */
           td->td_frame->tf_esp =
               (int)ke->ke_stack.ss_sp + ke->ke_stack.ss_size - 16;
           td->td_frame->tf_eip = (int)ke->ke_upcall;
   
           /*
            * Pass the address of the mailbox for this kse to the uts
            * function as a parameter on the stack.
            */
           suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
               (int)ke->ke_mailbox);
   }
   
   void
   cpu_wait(p)
           struct proc *p;
   {
   }
   
   /*
    * Convert kernel VA to physical address
    */
   u_long
   kvtop(void *addr)
   {
           vm_offset_t va;
   
           va = pmap_kextract((vm_offset_t)addr);
           if (va == 0)
                   panic("kvtop: zero page frame");
           return((int)va);
   }
   
   /*
    * Map an IO request into kernel virtual address space.
    *
    * All requests are (re)mapped into kernel VA space.
    * Notice that we use b_bufsize for the size of the buffer
    * to be mapped.  b_bcount might be modified by the driver.
    */
   void
   vmapbuf(bp)
           register struct buf *bp;
   {
           register caddr_t addr, kva;
           vm_offset_t pa;
           int pidx;
           struct vm_page *m;
   
           GIANT_REQUIRED;
   
           if ((bp->b_flags & B_PHYS) == 0)
                   panic("vmapbuf");
   
           for (addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data), pidx = 0;
                addr < bp->b_data + bp->b_bufsize;
                addr += PAGE_SIZE, pidx++) {
                   /*
                    * Do the vm_fault if needed; do the copy-on-write thing
                    * when reading stuff off device into memory.
                    */
                   vm_fault_quick((addr >= bp->b_data) ? addr : bp->b_data,
                           (bp->b_iocmd == BIO_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ);
                   pa = trunc_page(pmap_kextract((vm_offset_t) addr));
                   if (pa == 0)
                           panic("vmapbuf: page not present");
                   m = PHYS_TO_VM_PAGE(pa);
                   vm_page_hold(m);
                   bp->b_pages[pidx] = m;
           }
           if (pidx > btoc(MAXPHYS))
                   panic("vmapbuf: mapped more than MAXPHYS");
           pmap_qenter((vm_offset_t)bp->b_saveaddr, bp->b_pages, pidx);
           
           kva = bp->b_saveaddr;
           bp->b_npages = pidx;
           bp->b_saveaddr = bp->b_data;
           bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
   }
   
   /*
    * Free the io map PTEs associated with this IO operation.
    * We also invalidate the TLB entries and restore the original b_addr.
    */
   void
   vunmapbuf(bp)
           register struct buf *bp;
   {
           int pidx;
           int npages;
   
           GIANT_REQUIRED;
   
           if ((bp->b_flags & B_PHYS) == 0)
                   panic("vunmapbuf");
   
           npages = bp->b_npages;
           pmap_qremove(trunc_page((vm_offset_t)bp->b_data),
                        npages);
           vm_page_lock_queues();
           for (pidx = 0; pidx < npages; pidx++)
                   vm_page_unhold(bp->b_pages[pidx]);
           vm_page_unlock_queues();
   
           bp->b_data = bp->b_saveaddr;
   }
   
   /*
    * Force reset the processor by invalidating the entire address space!
    */
   
   #ifdef SMP
   static void
   cpu_reset_proxy()
   {
   
           cpu_reset_proxy_active = 1;
           while (cpu_reset_proxy_active == 1)
                   ;        /* Wait for other cpu to see that we've started */
           stop_cpus((1<<cpu_reset_proxyid));
           printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
           DELAY(1000000);
           cpu_reset_real();
   }
   #endif
   
   void
   cpu_reset()
   {
   #ifdef SMP
           if (smp_active == 0) {
                   cpu_reset_real();
                   /* NOTREACHED */
           } else {
   
                   u_int map;
                   int cnt;
                   printf("cpu_reset called on cpu#%d\n", PCPU_GET(cpuid));
   
                   map = PCPU_GET(other_cpus) & ~ stopped_cpus;
   
                   if (map != 0) {
                           printf("cpu_reset: Stopping other CPUs\n");
                           stop_cpus(map);         /* Stop all other CPUs */
                   }
   
                   if (PCPU_GET(cpuid) == 0) {
                           DELAY(1000000);
                           cpu_reset_real();
                           /* NOTREACHED */
                   } else {
                           /* We are not BSP (CPU #0) */
   
                           cpu_reset_proxyid = PCPU_GET(cpuid);
                           cpustop_restartfunc = cpu_reset_proxy;
                           cpu_reset_proxy_active = 0;
                           printf("cpu_reset: Restarting BSP\n");
                           started_cpus = (1<<0);          /* Restart CPU #0 */
   
                           cnt = 0;
                           while (cpu_reset_proxy_active == 0 && cnt < 10000000)
                                   cnt++;  /* Wait for BSP to announce restart */
                           if (cpu_reset_proxy_active == 0)
                                   printf("cpu_reset: Failed to restart BSP\n");
                           enable_intr();
                           cpu_reset_proxy_active = 2;
   
                           while (1);
                           /* NOTREACHED */
                   }
           }
   #else
           cpu_reset_real();
   #endif
   }
   
   static void
   cpu_reset_real()
   {
   
   #ifdef PC98
           /*
            * Attempt to do a CPU reset via CPU reset port.
            */
           disable_intr();
           if ((inb(0x35) & 0xa0) != 0xa0) {
                   outb(0x37, 0x0f);               /* SHUT0 = 0. */
                   outb(0x37, 0x0b);               /* SHUT1 = 0. */
           }
           outb(0xf0, 0x00);               /* Reset. */
   #else
           /*
            * Attempt to do a CPU reset via the keyboard controller,
            * do not turn of the GateA20, as any machine that fails
            * to do the reset here would then end up in no man's land.
            */
   
   #if !defined(BROKEN_KEYBOARD_RESET)
           outb(IO_KBD + 4, 0xFE);
           DELAY(500000);  /* wait 0.5 sec to see if that did it */
           printf("Keyboard reset did not work, attempting CPU shutdown\n");
           DELAY(1000000); /* wait 1 sec for printf to complete */
   #endif
   #endif /* PC98 */
           /* force a shutdown by unmapping entire address space ! */
           bzero((caddr_t) PTD, PAGE_SIZE);
   
           /* "good night, sweet prince .... <THUNK!>" */
           invltlb();
           /* NOTREACHED */
           while(1);
   }
   
   /*
    * Software interrupt handler for queued VM system processing.
    */   
   void  
   swi_vm(void *dummy) 
   {     
           if (busdma_swi_pending != 0)
                   busdma_swi();
   }
   
   /*
    * Tell whether this address is in some physical memory region.
    * Currently used by the kernel coredump code in order to avoid
    * dumping the ``ISA memory hole'' which could cause indefinite hangs,
    * or other unpredictable behaviour.
    */
   
   int
   is_physical_memory(addr)
           vm_offset_t addr;
   {
   
   #ifdef DEV_ISA
           /* The ISA ``memory hole''. */
           if (addr >= 0xa0000 && addr < 0x100000)
                   return 0;
   #endif
   
           /*
            * stuff other tests for known memory-mapped devices (PCI?)
            * here
            */
   
           return 1;
   }

Cache object: 0c2412a15870ae01a65d7f821718861b