FreeBSD/Linux Kernel Cross Reference
sys/uvm/uvm_glue.c

     /*      $OpenBSD: uvm_glue.c,v 1.84 2022/09/10 20:35:29 miod Exp $      */
     /*      $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $        */
     
     /* 
      * Copyright (c) 1997 Charles D. Cranor and Washington University.
      * Copyright (c) 1991, 1993, The Regents of the University of California.  
      *
      * All rights reserved.
      *
     * This code is derived from software contributed to Berkeley by
     * The Mach Operating System project at Carnegie-Mellon University.
     *
     * 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. 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.
     *
     *      @(#)vm_glue.c   8.6 (Berkeley) 1/5/94
     * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp
     *
     *
     * Copyright (c) 1987, 1990 Carnegie-Mellon University.
     * All rights reserved.
     * 
     * Permission to use, copy, modify and distribute this software and
     * its documentation is hereby granted, provided that both the copyright
     * notice and this permission notice appear in all copies of the
     * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
     * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     *
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     *
     * any improvements or extensions that they make and grant Carnegie the
     * rights to redistribute these changes.
     */
    
    /*
     * uvm_glue.c: glue functions
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/resourcevar.h>
    #include <sys/buf.h>
    #include <sys/user.h>
    #ifdef SYSVSHM
    #include <sys/shm.h>
    #endif
    #include <sys/sched.h>
    
    #include <uvm/uvm.h>
    
    /*
     * uvm_kernacc: can the kernel access a region of memory
     *
     * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c)
     */
    boolean_t
    uvm_kernacc(caddr_t addr, size_t len, int rw)
    {
            boolean_t rv;
            vaddr_t saddr, eaddr;
            vm_prot_t prot = rw == B_READ ? PROT_READ : PROT_WRITE;
    
            saddr = trunc_page((vaddr_t)addr);
            eaddr = round_page((vaddr_t)addr + len);
            vm_map_lock_read(kernel_map);
            rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot);
            vm_map_unlock_read(kernel_map);
    
           return rv;
   }
   
   /*
    * uvm_vslock: wire user memory for I/O
    *
    * - called from sys_sysctl
    */
   int
   uvm_vslock(struct proc *p, caddr_t addr, size_t len, vm_prot_t access_type)
   {
           struct vm_map *map = &p->p_vmspace->vm_map;
           vaddr_t start, end;
   
           start = trunc_page((vaddr_t)addr);
           end = round_page((vaddr_t)addr + len);
           if (end <= start)
                   return (EINVAL);
   
           return uvm_fault_wire(map, start, end, access_type);
   }
   
   /*
    * uvm_vsunlock: unwire user memory wired by uvm_vslock()
    *
    * - called from sys_sysctl
    */
   void
   uvm_vsunlock(struct proc *p, caddr_t addr, size_t len)
   {
           vaddr_t start, end;
   
           start = trunc_page((vaddr_t)addr);
           end = round_page((vaddr_t)addr + len);
           KASSERT(end > start);
   
           uvm_fault_unwire(&p->p_vmspace->vm_map, start, end);
   }
   
   /*
    * uvm_vslock_device: wire user memory, make sure it's device reachable
    *  and bounce if necessary.
    *
    * - called from physio
    */
   int
   uvm_vslock_device(struct proc *p, void *addr, size_t len,
       vm_prot_t access_type, void **retp)
   {
           struct vm_map *map = &p->p_vmspace->vm_map;
           struct vm_page *pg;
           struct pglist pgl;
           int npages;
           vaddr_t start, end, off;
           vaddr_t sva, va;
           vsize_t sz;
           int error, mapv, i;
   
           start = trunc_page((vaddr_t)addr);
           end = round_page((vaddr_t)addr + len);
           sz = end - start;
           off = (vaddr_t)addr - start;
           if (end <= start)
                   return (EINVAL);
   
           vm_map_lock_read(map);
   retry:
           mapv = map->timestamp;
           vm_map_unlock_read(map);
   
           if ((error = uvm_fault_wire(map, start, end, access_type)))
                   return (error);
   
           vm_map_lock_read(map);
           if (mapv != map->timestamp)
                   goto retry;
   
           npages = atop(sz);
           for (i = 0; i < npages; i++) {
                   paddr_t pa;
   
                   if (!pmap_extract(map->pmap, start + ptoa(i), &pa)) {
                           error = EFAULT;
                           goto out_unwire;
                   }
                   if (!PADDR_IS_DMA_REACHABLE(pa))
                           break;
           }
           if (i == npages) {
                   *retp = NULL;
                   return (0);
           }
   
           va = (vaddr_t)km_alloc(sz, &kv_any, &kp_none, &kd_nowait);
           if (va == 0) {
                   error = ENOMEM;
                   goto out_unwire;
           }
           sva = va;
   
           TAILQ_INIT(&pgl);
           error = uvm_pglistalloc(npages * PAGE_SIZE, dma_constraint.ucr_low,
               dma_constraint.ucr_high, 0, 0, &pgl, npages, UVM_PLA_WAITOK);
           if (error)
                   goto out_unmap;
   
           while ((pg = TAILQ_FIRST(&pgl)) != NULL) {
                   TAILQ_REMOVE(&pgl, pg, pageq);
                   pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg), PROT_READ | PROT_WRITE);
                   va += PAGE_SIZE;
           }
           pmap_update(pmap_kernel());
           KASSERT(va == sva + sz);
           *retp = (void *)(sva + off);
   
           if ((error = copyin(addr, *retp, len)) == 0)
                   return 0;
   
           uvm_km_pgremove_intrsafe(sva, sva + sz);
           pmap_kremove(sva, sz);
           pmap_update(pmap_kernel());
   out_unmap:
           km_free((void *)sva, sz, &kv_any, &kp_none);
   out_unwire:
           uvm_fault_unwire_locked(map, start, end);
           vm_map_unlock_read(map);
           return (error);
   }
   
   /*
    * uvm_vsunlock_device: unwire user memory wired by uvm_vslock_device()
    *
    * - called from physio
    */
   void
   uvm_vsunlock_device(struct proc *p, void *addr, size_t len, void *map)
   {
           vaddr_t start, end;
           vaddr_t kva;
           vsize_t sz;
   
           start = trunc_page((vaddr_t)addr);
           end = round_page((vaddr_t)addr + len);
           KASSERT(end > start);
           sz = end - start;
   
           if (map)
                   copyout(map, addr, len);
   
           uvm_fault_unwire_locked(&p->p_vmspace->vm_map, start, end);
           vm_map_unlock_read(&p->p_vmspace->vm_map);
   
           if (!map)
                   return;
   
           kva = trunc_page((vaddr_t)map);
           uvm_km_pgremove_intrsafe(kva, kva + sz);
           pmap_kremove(kva, sz);
           pmap_update(pmap_kernel());
           uvm_km_free(kernel_map, kva, sz);
   }
   
   /*
    * uvm_uarea_alloc: allocate the u-area for a new thread
    */
   vaddr_t
   uvm_uarea_alloc(void)
   {
           vaddr_t uaddr;
   
           uaddr = uvm_km_kmemalloc_pla(kernel_map, uvm.kernel_object, USPACE,
               USPACE_ALIGN, UVM_KMF_ZERO,
               no_constraint.ucr_low, no_constraint.ucr_high,
               0, 0, USPACE/PAGE_SIZE);
   
           return (uaddr);
   }
   
   /*
    * uvm_uarea_free: free a dead thread's stack
    *
    * - the thread passed to us is a dead thread; we
    *   are running on a different context now (the reaper).
    */
   void
   uvm_uarea_free(struct proc *p)
   {
           uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE);
           p->p_addr = NULL;
   }
   
   /*
    * uvm_exit: exit a virtual address space
    */
   void
   uvm_exit(struct process *pr)
   {
           struct vmspace *vm = pr->ps_vmspace;
   
           pr->ps_vmspace = NULL;
           uvmspace_free(vm);
   }
   
   /*
    * uvm_init_limit: init per-process VM limits
    *
    * - called for process 0 and then inherited by all others.
    */
   void
   uvm_init_limits(struct plimit *limit0)
   {
           /*
            * Set up the initial limits on process VM.  Set the maximum
            * resident set size to be all of (reasonably) available memory.
            * This causes any single, large process to start random page
            * replacement once it fills memory.
            */
           limit0->pl_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
           limit0->pl_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ;
           limit0->pl_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
           limit0->pl_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ;
           limit0->pl_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free);
   }
   
   #ifdef __HAVE_PMAP_COLLECT
   
   #ifdef DEBUG
   int     enableswap = 1;
   int     swapdebug = 0;
   #define SDB_FOLLOW      1
   #define SDB_SWAPIN      2
   #define SDB_SWAPOUT     4
   #endif
   
   
   /*
    * swapout_threads: find threads that can be swapped
    *
    * - called by the pagedaemon
    * - try and swap at least one process
    * - processes that are sleeping or stopped for maxslp or more seconds
    *   are swapped... otherwise the longest-sleeping or stopped process
    *   is swapped, otherwise the longest resident process...
    */
   void
   uvm_swapout_threads(void)
   {
           struct process *pr;
           struct proc *p, *slpp;
           struct process *outpr;
           int outpri;
           int didswap = 0;
           extern int maxslp; 
           /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */
   
   #ifdef DEBUG
           if (!enableswap)
                   return;
   #endif
   
           /*
            * outpr/outpri  : stop/sleep process whose most active thread has
            *      the largest sleeptime < maxslp
            */
           outpr = NULL;
           outpri = 0;
           LIST_FOREACH(pr, &allprocess, ps_list) {
                   if (pr->ps_flags & (PS_SYSTEM | PS_EXITING))
                           continue;
   
                   /*
                    * slpp: the sleeping or stopped thread in pr with
                    * the smallest p_slptime
                    */
                   slpp = NULL;
                   TAILQ_FOREACH(p, &pr->ps_threads, p_thr_link) {
                           switch (p->p_stat) {
                           case SRUN:
                           case SONPROC:
                                   goto next_process;
   
                           case SSLEEP:
                           case SSTOP:
                                   if (slpp == NULL ||
                                       slpp->p_slptime < p->p_slptime)
                                           slpp = p;
                                   continue;
                           }
                   }
   
                   if (slpp != NULL) {
                           if (slpp->p_slptime >= maxslp) {
                                   pmap_collect(pr->ps_vmspace->vm_map.pmap);
                                   didswap++;
                           } else if (slpp->p_slptime > outpri) {
                                   outpr = pr;
                                   outpri = slpp->p_slptime;
                           }
                   }
   next_process:   ;
           }
   
           /*
            * If we didn't get rid of any real duds, toss out the next most
            * likely sleeping/stopped or running candidate.  We only do this
            * if we are real low on memory since we don't gain much by doing
            * it.
            */
           if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE)) &&
               outpr != NULL) {
   #ifdef DEBUG
                   if (swapdebug & SDB_SWAPOUT)
                           printf("swapout_threads: no duds, try procpr %p\n",
                               outpr);
   #endif
                   pmap_collect(outpr->ps_vmspace->vm_map.pmap);
           }
   }
   
   #endif  /* __HAVE_PMAP_COLLECT */
   
   /*
    * uvm_atopg: convert KVAs back to their page structures.
    */
   struct vm_page *
   uvm_atopg(vaddr_t kva)
   {
           struct vm_page *pg;
           paddr_t pa;
           boolean_t rv;
    
           rv = pmap_extract(pmap_kernel(), kva, &pa);
           KASSERT(rv);
           pg = PHYS_TO_VM_PAGE(pa);
           KASSERT(pg != NULL);
           return (pg);
   }
   
   void
   uvm_pause(void)
   {
           static unsigned int toggle;
           if (toggle++ > 128) {
                   toggle = 0;
                   KERNEL_UNLOCK();
                   KERNEL_LOCK();
           }
           sched_pause(preempt);
   }
   
   #ifndef SMALL_KERNEL
   int
   fill_vmmap(struct process *pr, struct kinfo_vmentry *kve,
       size_t *lenp)
   {
           struct vm_map *map;
   
           if (pr != NULL)
                   map = &pr->ps_vmspace->vm_map;
           else
                   map = kernel_map;
           return uvm_map_fill_vmmap(map, kve, lenp);
   }
   #endif

Cache object: 4579393eb1d278f473892c8c6ea7456f