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

     /*      $NetBSD: uvm_glue.c,v 1.181 2020/06/14 21:41:42 ad 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.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.181 2020/06/14 21:41:42 ad Exp $");
    
    #include "opt_kgdb.h"
    #include "opt_kstack.h"
    #include "opt_uvmhist.h"
    
    /*
     * uvm_glue.c: glue functions
     */
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/resourcevar.h>
    #include <sys/buf.h>
    #include <sys/syncobj.h>
    #include <sys/cpu.h>
    #include <sys/atomic.h>
    #include <sys/lwp.h>
    #include <sys/asan.h>
    
    #include <uvm/uvm.h>
    #include <uvm/uvm_pdpolicy.h>
    #include <uvm/uvm_pgflcache.h>
    
    /*
     * uvm_kernacc: test if kernel can access a memory region.
     *
     * => Currently used only by /dev/kmem driver (dev/mm.c).
     */
    bool
    uvm_kernacc(void *addr, size_t len, vm_prot_t prot)
    {
           vaddr_t saddr = trunc_page((vaddr_t)addr);
           vaddr_t eaddr = round_page(saddr + len);
           bool rv;
   
           vm_map_lock_read(kernel_map);
           rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot);
           vm_map_unlock_read(kernel_map);
   
           return rv;
   }
   
   #ifdef KGDB
   /*
    * Change protections on kernel pages from addr to addr+len
    * (presumably so debugger can plant a breakpoint).
    *
    * We force the protection change at the pmap level.  If we were
    * to use vm_map_protect a change to allow writing would be lazily-
    * applied meaning we would still take a protection fault, something
    * we really don't want to do.  It would also fragment the kernel
    * map unnecessarily.  We cannot use pmap_protect since it also won't
    * enforce a write-enable request.  Using pmap_enter is the only way
    * we can ensure the change takes place properly.
    */
   void
   uvm_chgkprot(void *addr, size_t len, int rw)
   {
           vm_prot_t prot;
           paddr_t pa;
           vaddr_t sva, eva;
   
           prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
           eva = round_page((vaddr_t)addr + len);
           for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) {
                   /*
                    * Extract physical address for the page.
                    */
                   if (pmap_extract(pmap_kernel(), sva, &pa) == false)
                           panic("%s: invalid page", __func__);
                   pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED);
           }
           pmap_update(pmap_kernel());
   }
   #endif
   
   /*
    * uvm_vslock: wire user memory for I/O
    *
    * - called from physio and sys___sysctl
    * - XXXCDC: consider nuking this (or making it a macro?)
    */
   
   int
   uvm_vslock(struct vmspace *vs, void *addr, size_t len, vm_prot_t access_type)
   {
           struct vm_map *map;
           vaddr_t start, end;
           int error;
   
           map = &vs->vm_map;
           start = trunc_page((vaddr_t)addr);
           end = round_page((vaddr_t)addr + len);
           error = uvm_fault_wire(map, start, end, access_type, 0);
           return error;
   }
   
   /*
    * uvm_vsunlock: unwire user memory wired by uvm_vslock()
    *
    * - called from physio and sys___sysctl
    * - XXXCDC: consider nuking this (or making it a macro?)
    */
   
   void
   uvm_vsunlock(struct vmspace *vs, void *addr, size_t len)
   {
           uvm_fault_unwire(&vs->vm_map, trunc_page((vaddr_t)addr),
                   round_page((vaddr_t)addr + len));
   }
   
   /*
    * uvm_proc_fork: fork a virtual address space
    *
    * - the address space is copied as per parent map's inherit values
    */
   void
   uvm_proc_fork(struct proc *p1, struct proc *p2, bool shared)
   {
   
           if (shared == true) {
                   p2->p_vmspace = NULL;
                   uvmspace_share(p1, p2);
           } else {
                   p2->p_vmspace = uvmspace_fork(p1->p_vmspace);
           }
   
           cpu_proc_fork(p1, p2);
   }
   
   /*
    * uvm_lwp_fork: fork a thread
    *
    * - a new PCB structure is allocated for the child process,
    *      and filled in by MD layer
    * - if specified, the child gets a new user stack described by
    *      stack and stacksize
    * - NOTE: the kernel stack may be at a different location in the child
    *      process, and thus addresses of automatic variables may be invalid
    *      after cpu_lwp_fork returns in the child process.  We do nothing here
    *      after cpu_lwp_fork returns.
    */
   void
   uvm_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
       void (*func)(void *), void *arg)
   {
   
           /* Fill stack with magic number. */
           kstack_setup_magic(l2);
   
           /*
            * cpu_lwp_fork() copy and update the pcb, and make the child ready
            * to run.  If this is a normal user fork, the child will exit
            * directly to user mode via child_return() on its first time
            * slice and will not return here.  If this is a kernel thread,
            * the specified entry point will be executed.
            */
           cpu_lwp_fork(l1, l2, stack, stacksize, func, arg);
   }
   
   #ifndef USPACE_ALIGN
   #define USPACE_ALIGN    0
   #endif
   
   static pool_cache_t uvm_uarea_cache;
   #if defined(__HAVE_CPU_UAREA_ROUTINES)
   static pool_cache_t uvm_uarea_system_cache;
   #else
   #define uvm_uarea_system_cache uvm_uarea_cache
   #endif
   
   static void *
   uarea_poolpage_alloc(struct pool *pp, int flags)
   {
   
           KASSERT((flags & PR_WAITOK) != 0);
   
   #if defined(PMAP_MAP_POOLPAGE)
           while (USPACE == PAGE_SIZE &&
               (USPACE_ALIGN == 0 || USPACE_ALIGN == PAGE_SIZE)) {
                   struct vm_page *pg;
                   vaddr_t va;
   #if defined(PMAP_ALLOC_POOLPAGE)
                   pg = PMAP_ALLOC_POOLPAGE(0);
   #else
                   pg = uvm_pagealloc(NULL, 0, NULL, 0);
   #endif
                   if (pg == NULL) {
                           uvm_wait("uarea");
                           continue;
                   }
                   va = PMAP_MAP_POOLPAGE(VM_PAGE_TO_PHYS(pg));
                   KASSERT(va != 0);
                   return (void *)va;
           }
   #endif
   #if defined(__HAVE_CPU_UAREA_ROUTINES)
           void *va = cpu_uarea_alloc(false);
           if (va)
                   return (void *)va;
   #endif
           return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz,
               USPACE_ALIGN, UVM_KMF_WIRED | UVM_KMF_WAITVA);
   }
   
   static void
   uarea_poolpage_free(struct pool *pp, void *addr)
   {
   #if defined(PMAP_MAP_POOLPAGE)
           if (USPACE == PAGE_SIZE &&
               (USPACE_ALIGN == 0 || USPACE_ALIGN == PAGE_SIZE)) {
                   paddr_t pa;
   
                   pa = PMAP_UNMAP_POOLPAGE((vaddr_t) addr);
                   KASSERT(pa != 0);
                   uvm_pagefree(PHYS_TO_VM_PAGE(pa));
                   return;
           }
   #endif
   #if defined(__HAVE_CPU_UAREA_ROUTINES)
           if (cpu_uarea_free(addr))
                   return;
   #endif
           uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz,
               UVM_KMF_WIRED);
   }
   
   static struct pool_allocator uvm_uarea_allocator = {
           .pa_alloc = uarea_poolpage_alloc,
           .pa_free = uarea_poolpage_free,
           .pa_pagesz = USPACE,
   };
   
   #if defined(__HAVE_CPU_UAREA_ROUTINES)
   static void *
   uarea_system_poolpage_alloc(struct pool *pp, int flags)
   {
           void * const va = cpu_uarea_alloc(true);
           if (va != NULL)
                   return va;
   
           return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz,
               USPACE_ALIGN, UVM_KMF_WIRED |
               ((flags & PR_WAITOK) ? UVM_KMF_WAITVA :
               (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK)));
   }
   
   static void
   uarea_system_poolpage_free(struct pool *pp, void *addr)
   {
           if (cpu_uarea_free(addr))
                   return;
   
           uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz,
               UVM_KMF_WIRED);
   }
   
   static struct pool_allocator uvm_uarea_system_allocator = {
           .pa_alloc = uarea_system_poolpage_alloc,
           .pa_free = uarea_system_poolpage_free,
           .pa_pagesz = USPACE,
   };
   #endif /* __HAVE_CPU_UAREA_ROUTINES */
   
   void
   uvm_uarea_init(void)
   {
           int flags = PR_NOTOUCH;
   
           /*
            * specify PR_NOALIGN unless the alignment provided by
            * the backend (USPACE_ALIGN) is sufficient to provide
            * pool page size (UPSACE) alignment.
            */
   
           if ((USPACE_ALIGN == 0 && USPACE != PAGE_SIZE) ||
               (USPACE_ALIGN % USPACE) != 0) {
                   flags |= PR_NOALIGN;
           }
   
           uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0, flags,
               "uarea", &uvm_uarea_allocator, IPL_NONE, NULL, NULL, NULL);
   #if defined(__HAVE_CPU_UAREA_ROUTINES)
           uvm_uarea_system_cache = pool_cache_init(USPACE, USPACE_ALIGN,
               0, flags, "uareasys", &uvm_uarea_system_allocator,
               IPL_NONE, NULL, NULL, NULL);
   #endif
   }
   
   /*
    * uvm_uarea_alloc: allocate a u-area
    */
   
   vaddr_t
   uvm_uarea_alloc(void)
   {
   
           return (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK);
   }
   
   vaddr_t
   uvm_uarea_system_alloc(struct cpu_info *ci)
   {
   #ifdef __HAVE_CPU_UAREA_ALLOC_IDLELWP
           if (__predict_false(ci != NULL))
                   return cpu_uarea_alloc_idlelwp(ci);
   #endif
   
           return (vaddr_t)pool_cache_get(uvm_uarea_system_cache, PR_WAITOK);
   }
   
   /*
    * uvm_uarea_free: free a u-area
    */
   
   void
   uvm_uarea_free(vaddr_t uaddr)
   {
   
           kasan_mark((void *)uaddr, USPACE, USPACE, 0);
           pool_cache_put(uvm_uarea_cache, (void *)uaddr);
   }
   
   void
   uvm_uarea_system_free(vaddr_t uaddr)
   {
   
           kasan_mark((void *)uaddr, USPACE, USPACE, 0);
           pool_cache_put(uvm_uarea_system_cache, (void *)uaddr);
   }
   
   vaddr_t
   uvm_lwp_getuarea(lwp_t *l)
   {
   
           return (vaddr_t)l->l_addr - UAREA_PCB_OFFSET;
   }
   
   void
   uvm_lwp_setuarea(lwp_t *l, vaddr_t addr)
   {
   
           l->l_addr = (void *)(addr + UAREA_PCB_OFFSET);
   }
   
   /*
    * uvm_proc_exit: exit a virtual address space
    *
    * - borrow proc0's address space because freeing the vmspace
    *   of the dead process may block.
    */
   
   void
   uvm_proc_exit(struct proc *p)
   {
           struct lwp *l = curlwp; /* XXX */
           struct vmspace *ovm;
   
           KASSERT(p == l->l_proc);
           ovm = p->p_vmspace;
           KASSERT(ovm != NULL);
   
           if (__predict_false(ovm == proc0.p_vmspace))
                   return;
   
           /*
            * borrow proc0's address space.
            */
           kpreempt_disable();
           pmap_deactivate(l);
           p->p_vmspace = proc0.p_vmspace;
           pmap_activate(l);
           kpreempt_enable();
   
           uvmspace_free(ovm);
   }
   
   void
   uvm_lwp_exit(struct lwp *l)
   {
           vaddr_t va = uvm_lwp_getuarea(l);
           bool system = (l->l_flag & LW_SYSTEM) != 0;
   
           if (system)
                   uvm_uarea_system_free(va);
           else
                   uvm_uarea_free(va);
   #ifdef DIAGNOSTIC
           uvm_lwp_setuarea(l, (vaddr_t)NULL);
   #endif
   }
   
   /*
    * uvm_init_limit: init per-process VM limits
    *
    * - called for process 0 and then inherited by all others.
    */
   
   void
   uvm_init_limits(struct proc *p)
   {
   
           /*
            * 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.
            */
   
           p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
           p->p_rlimit[RLIMIT_STACK].rlim_max = maxsmap;
           p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
           p->p_rlimit[RLIMIT_DATA].rlim_max = maxdmap;
           p->p_rlimit[RLIMIT_AS].rlim_cur = RLIM_INFINITY;
           p->p_rlimit[RLIMIT_AS].rlim_max = RLIM_INFINITY;
           p->p_rlimit[RLIMIT_RSS].rlim_cur = MIN(VM_MAXUSER_ADDRESS,
               ctob((rlim_t)uvm_availmem(false)));
   }
   
   /*
    * uvm_scheduler: process zero main loop.
    */
   
   extern struct loadavg averunnable;
   
   void
   uvm_scheduler(void)
   {
           lwp_t *l = curlwp;
   
           lwp_lock(l);
           l->l_class = SCHED_FIFO;
           lwp_changepri(l, PRI_VM);
           lwp_unlock(l);
   
           /* Start the freelist cache. */
           uvm_pgflcache_start();
   
           for (;;) {
                   /* Update legacy stats for post-mortem debugging. */
                   uvm_update_uvmexp();
   
                   /* See if the pagedaemon needs to generate some free pages. */
                   uvm_kick_pdaemon();
   
                   /* Calculate process statistics. */
                   sched_pstats();
                   (void)kpause("uvm", false, hz, NULL);
           }
   }
   
   /*
    * uvm_idle: called from the idle loop.
    */
   
   void
   uvm_idle(void)
   {
           struct cpu_info *ci = curcpu();
           struct uvm_cpu *ucpu = ci->ci_data.cpu_uvm;
   
           KASSERT(kpreempt_disabled());
   
           if (!ci->ci_want_resched)
                   uvmpdpol_idle(ucpu);
   }

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