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

     /*      $NetBSD: uvm_km.c,v 1.162 2022/08/06 05:55:37 chs 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_kern.c   8.3 (Berkeley) 1/12/94
     * from: Id: uvm_km.c,v 1.1.2.14 1998/02/06 05:19:27 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_km.c: handle kernel memory allocation and management
     */
    
    /*
     * overview of kernel memory management:
     *
     * the kernel virtual address space is mapped by "kernel_map."   kernel_map
     * starts at VM_MIN_KERNEL_ADDRESS and goes to VM_MAX_KERNEL_ADDRESS.
     * note that VM_MIN_KERNEL_ADDRESS is equal to vm_map_min(kernel_map).
     *
     * the kernel_map has several "submaps."   submaps can only appear in
     * the kernel_map (user processes can't use them).   submaps "take over"
     * the management of a sub-range of the kernel's address space.  submaps
     * are typically allocated at boot time and are never released.   kernel
     * virtual address space that is mapped by a submap is locked by the
     * submap's lock -- not the kernel_map's lock.
     *
     * thus, the useful feature of submaps is that they allow us to break
     * up the locking and protection of the kernel address space into smaller
     * chunks.
     *
     * the vm system has several standard kernel submaps/arenas, including:
     *   kmem_arena => used for kmem/pool (memoryallocators(9))
     *   pager_map => used to map "buf" structures into kernel space
     *   exec_map => used during exec to handle exec args
     *   etc...
     *
     * The kmem_arena is a "special submap", as it lives in a fixed map entry
     * within the kernel_map and is controlled by vmem(9).
     *
     * the kernel allocates its private memory out of special uvm_objects whose
     * reference count is set to UVM_OBJ_KERN (thus indicating that the objects
     * are "special" and never die).   all kernel objects should be thought of
     * as large, fixed-sized, sparsely populated uvm_objects.   each kernel
     * object is equal to the size of kernel virtual address space (i.e. the
    * value "VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS").
    *
    * note that just because a kernel object spans the entire kernel virtual
    * address space doesn't mean that it has to be mapped into the entire space.
    * large chunks of a kernel object's space go unused either because
    * that area of kernel VM is unmapped, or there is some other type of
    * object mapped into that range (e.g. a vnode).    for submap's kernel
    * objects, the only part of the object that can ever be populated is the
    * offsets that are managed by the submap.
    *
    * note that the "offset" in a kernel object is always the kernel virtual
    * address minus the VM_MIN_KERNEL_ADDRESS (aka vm_map_min(kernel_map)).
    * example:
    *   suppose VM_MIN_KERNEL_ADDRESS is 0xf8000000 and the kernel does a
    *   uvm_km_alloc(kernel_map, PAGE_SIZE) [allocate 1 wired down page in the
    *   kernel map].    if uvm_km_alloc returns virtual address 0xf8235000,
    *   then that means that the page at offset 0x235000 in kernel_object is
    *   mapped at 0xf8235000.
    *
    * kernel object have one other special property: when the kernel virtual
    * memory mapping them is unmapped, the backing memory in the object is
    * freed right away.   this is done with the uvm_km_pgremove() function.
    * this has to be done because there is no backing store for kernel pages
    * and no need to save them after they are no longer referenced.
    *
    * Generic arenas:
    *
    * kmem_arena:
    *      Main arena controlling the kernel KVA used by other arenas.
    *
    * kmem_va_arena:
    *      Implements quantum caching in order to speedup allocations and
    *      reduce fragmentation.  The pool(9), unless created with a custom
    *      meta-data allocator, and kmem(9) subsystems use this arena.
    *
    * Arenas for meta-data allocations are used by vmem(9) and pool(9).
    * These arenas cannot use quantum cache.  However, kmem_va_meta_arena
    * compensates this by importing larger chunks from kmem_arena.
    *
    * kmem_va_meta_arena:
    *      Space for meta-data.
    *
    * kmem_meta_arena:
    *      Imports from kmem_va_meta_arena.  Allocations from this arena are
    *      backed with the pages.
    *
    * Arena stacking:
    *
    *      kmem_arena
    *              kmem_va_arena
    *              kmem_va_meta_arena
    *                      kmem_meta_arena
    */
   
   #include <sys/cdefs.h>
   __KERNEL_RCSID(0, "$NetBSD: uvm_km.c,v 1.162 2022/08/06 05:55:37 chs Exp $");
   
   #include "opt_uvmhist.h"
   
   #include "opt_kmempages.h"
   
   #ifndef NKMEMPAGES
   #define NKMEMPAGES 0
   #endif
   
   /*
    * Defaults for lower and upper-bounds for the kmem_arena page count.
    * Can be overridden by kernel config options.
    */
   #ifndef NKMEMPAGES_MIN
   #define NKMEMPAGES_MIN NKMEMPAGES_MIN_DEFAULT
   #endif
   
   #ifndef NKMEMPAGES_MAX
   #define NKMEMPAGES_MAX NKMEMPAGES_MAX_DEFAULT
   #endif
   
   
   #include <sys/param.h>
   #include <sys/systm.h>
   #include <sys/atomic.h>
   #include <sys/proc.h>
   #include <sys/pool.h>
   #include <sys/vmem.h>
   #include <sys/vmem_impl.h>
   #include <sys/kmem.h>
   #include <sys/msan.h>
   
   #include <uvm/uvm.h>
   
   /*
    * global data structures
    */
   
   struct vm_map *kernel_map = NULL;
   
   /*
    * local data structues
    */
   
   static struct vm_map            kernel_map_store;
   static struct vm_map_entry      kernel_image_mapent_store;
   static struct vm_map_entry      kernel_kmem_mapent_store;
   
   int nkmempages = 0;
   vaddr_t kmembase;
   vsize_t kmemsize;
   
   static struct vmem kmem_arena_store;
   vmem_t *kmem_arena = NULL;
   static struct vmem kmem_va_arena_store;
   vmem_t *kmem_va_arena;
   
   /*
    * kmeminit_nkmempages: calculate the size of kmem_arena.
    */
   void
   kmeminit_nkmempages(void)
   {
           int npages;
   
           if (nkmempages != 0) {
                   /*
                    * It's already been set (by us being here before)
                    * bail out now;
                    */
                   return;
           }
   
   #if defined(NKMEMPAGES_MAX_UNLIMITED) && !defined(KMSAN)
           npages = physmem;
   #else
   
   #if defined(KMSAN)
           npages = (physmem / 4);
   #elif defined(PMAP_MAP_POOLPAGE)
           npages = (physmem / 4);
   #else
           npages = (physmem / 3) * 2;
   #endif /* defined(PMAP_MAP_POOLPAGE) */
   
   #if !defined(NKMEMPAGES_MAX_UNLIMITED)
           if (npages > NKMEMPAGES_MAX)
                   npages = NKMEMPAGES_MAX;
   #endif
   
   #endif
   
           if (npages < NKMEMPAGES_MIN)
                   npages = NKMEMPAGES_MIN;
   
           nkmempages = npages;
   }
   
   /*
    * uvm_km_bootstrap: init kernel maps and objects to reflect reality (i.e.
    * KVM already allocated for text, data, bss, and static data structures).
    *
    * => KVM is defined by VM_MIN_KERNEL_ADDRESS/VM_MAX_KERNEL_ADDRESS.
    *    we assume that [vmin -> start] has already been allocated and that
    *    "end" is the end.
    */
   
   void
   uvm_km_bootstrap(vaddr_t start, vaddr_t end)
   {
           bool kmem_arena_small;
           vaddr_t base = VM_MIN_KERNEL_ADDRESS;
           struct uvm_map_args args;
           int error;
   
           UVMHIST_FUNC(__func__);
           UVMHIST_CALLARGS(maphist, "start=%#jx end=%#jx", start, end, 0,0);
   
           kmeminit_nkmempages();
           kmemsize = (vsize_t)nkmempages * PAGE_SIZE;
           kmem_arena_small = kmemsize < 64 * 1024 * 1024;
   
           UVMHIST_LOG(maphist, "kmemsize=%#jx", kmemsize, 0,0,0);
   
           /*
            * next, init kernel memory objects.
            */
   
           /* kernel_object: for pageable anonymous kernel memory */
           uvm_kernel_object = uao_create(VM_MAX_KERNEL_ADDRESS -
                                   VM_MIN_KERNEL_ADDRESS, UAO_FLAG_KERNOBJ);
   
           /*
            * init the map and reserve any space that might already
            * have been allocated kernel space before installing.
            */
   
           uvm_map_setup(&kernel_map_store, base, end, VM_MAP_PAGEABLE);
           kernel_map_store.pmap = pmap_kernel();
           if (start != base) {
                   error = uvm_map_prepare(&kernel_map_store,
                       base, start - base,
                       NULL, UVM_UNKNOWN_OFFSET, 0,
                       UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
                                   UVM_ADV_RANDOM, UVM_FLAG_FIXED), &args);
                   if (!error) {
                           kernel_image_mapent_store.flags =
                               UVM_MAP_KERNEL | UVM_MAP_STATIC | UVM_MAP_NOMERGE;
                           error = uvm_map_enter(&kernel_map_store, &args,
                               &kernel_image_mapent_store);
                   }
   
                   if (error)
                           panic(
                               "uvm_km_bootstrap: could not reserve space for kernel");
   
                   kmembase = args.uma_start + args.uma_size;
           } else {
                   kmembase = base;
           }
   
           error = uvm_map_prepare(&kernel_map_store,
               kmembase, kmemsize,
               NULL, UVM_UNKNOWN_OFFSET, 0,
               UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
                           UVM_ADV_RANDOM, UVM_FLAG_FIXED), &args);
           if (!error) {
                   kernel_kmem_mapent_store.flags =
                       UVM_MAP_KERNEL | UVM_MAP_STATIC | UVM_MAP_NOMERGE;
                   error = uvm_map_enter(&kernel_map_store, &args,
                       &kernel_kmem_mapent_store);
           }
   
           if (error)
                   panic("uvm_km_bootstrap: could not reserve kernel kmem");
   
           /*
            * install!
            */
   
           kernel_map = &kernel_map_store;
   
           pool_subsystem_init();
   
           kmem_arena = vmem_init(&kmem_arena_store, "kmem",
               kmembase, kmemsize, PAGE_SIZE, NULL, NULL, NULL,
               0, VM_NOSLEEP | VM_BOOTSTRAP, IPL_VM);
   #ifdef PMAP_GROWKERNEL
           /*
            * kmem_arena VA allocations happen independently of uvm_map.
            * grow kernel to accommodate the kmem_arena.
            */
           if (uvm_maxkaddr < kmembase + kmemsize) {
                   uvm_maxkaddr = pmap_growkernel(kmembase + kmemsize);
                   KASSERTMSG(uvm_maxkaddr >= kmembase + kmemsize,
                       "%#"PRIxVADDR" %#"PRIxVADDR" %#"PRIxVSIZE,
                       uvm_maxkaddr, kmembase, kmemsize);
           }
   #endif
   
           vmem_subsystem_init(kmem_arena);
   
           UVMHIST_LOG(maphist, "kmem vmem created (base=%#jx, size=%#jx",
               kmembase, kmemsize, 0,0);
   
           kmem_va_arena = vmem_init(&kmem_va_arena_store, "kva",
               0, 0, PAGE_SIZE, vmem_alloc, vmem_free, kmem_arena,
               (kmem_arena_small ? 4 : VMEM_QCACHE_IDX_MAX) * PAGE_SIZE,
               VM_NOSLEEP, IPL_VM);
   
           UVMHIST_LOG(maphist, "<- done", 0,0,0,0);
   }
   
   /*
    * uvm_km_init: init the kernel maps virtual memory caches
    * and start the pool/kmem allocator.
    */
   void
   uvm_km_init(void)
   {
           kmem_init();
   }
   
   /*
    * uvm_km_suballoc: allocate a submap in the kernel map.   once a submap
    * is allocated all references to that area of VM must go through it.  this
    * allows the locking of VAs in kernel_map to be broken up into regions.
    *
    * => if `fixed' is true, *vmin specifies where the region described
    *   pager_map => used to map "buf" structures into kernel space
    *      by the submap must start
    * => if submap is non NULL we use that as the submap, otherwise we
    *      alloc a new map
    */
   
   struct vm_map *
   uvm_km_suballoc(struct vm_map *map, vaddr_t *vmin /* IN/OUT */,
       vaddr_t *vmax /* OUT */, vsize_t size, int flags, bool fixed,
       struct vm_map *submap)
   {
           int mapflags = UVM_FLAG_NOMERGE | (fixed ? UVM_FLAG_FIXED : 0);
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KASSERT(vm_map_pmap(map) == pmap_kernel());
   
           size = round_page(size);        /* round up to pagesize */
   
           /*
            * first allocate a blank spot in the parent map
            */
   
           if (uvm_map(map, vmin, size, NULL, UVM_UNKNOWN_OFFSET, 0,
               UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
               UVM_ADV_RANDOM, mapflags)) != 0) {
                   panic("%s: unable to allocate space in parent map", __func__);
           }
   
           /*
            * set VM bounds (vmin is filled in by uvm_map)
            */
   
           *vmax = *vmin + size;
   
           /*
            * add references to pmap and create or init the submap
            */
   
           pmap_reference(vm_map_pmap(map));
           if (submap == NULL) {
                   submap = kmem_alloc(sizeof(*submap), KM_SLEEP);
           }
           uvm_map_setup(submap, *vmin, *vmax, flags);
           submap->pmap = vm_map_pmap(map);
   
           /*
            * now let uvm_map_submap plug in it...
            */
   
           if (uvm_map_submap(map, *vmin, *vmax, submap) != 0)
                   panic("uvm_km_suballoc: submap allocation failed");
   
           return(submap);
   }
   
   /*
    * uvm_km_pgremove: remove pages from a kernel uvm_object and KVA.
    */
   
   void
   uvm_km_pgremove(vaddr_t startva, vaddr_t endva)
   {
           struct uvm_object * const uobj = uvm_kernel_object;
           const voff_t start = startva - vm_map_min(kernel_map);
           const voff_t end = endva - vm_map_min(kernel_map);
           struct vm_page *pg;
           voff_t curoff, nextoff;
           int swpgonlydelta = 0;
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KASSERT(VM_MIN_KERNEL_ADDRESS <= startva);
           KASSERT(startva < endva);
           KASSERT(endva <= VM_MAX_KERNEL_ADDRESS);
   
           rw_enter(uobj->vmobjlock, RW_WRITER);
           pmap_remove(pmap_kernel(), startva, endva);
           for (curoff = start; curoff < end; curoff = nextoff) {
                   nextoff = curoff + PAGE_SIZE;
                   pg = uvm_pagelookup(uobj, curoff);
                   if (pg != NULL && pg->flags & PG_BUSY) {
                           uvm_pagewait(pg, uobj->vmobjlock, "km_pgrm");
                           rw_enter(uobj->vmobjlock, RW_WRITER);
                           nextoff = curoff;
                           continue;
                   }
   
                   /*
                    * free the swap slot, then the page.
                    */
   
                   if (pg == NULL &&
                       uao_find_swslot(uobj, curoff >> PAGE_SHIFT) > 0) {
                           swpgonlydelta++;
                   }
                   uao_dropswap(uobj, curoff >> PAGE_SHIFT);
                   if (pg != NULL) {
                           uvm_pagefree(pg);
                   }
           }
           rw_exit(uobj->vmobjlock);
   
           if (swpgonlydelta > 0) {
                   KASSERT(uvmexp.swpgonly >= swpgonlydelta);
                   atomic_add_int(&uvmexp.swpgonly, -swpgonlydelta);
           }
   }
   
   
   /*
    * uvm_km_pgremove_intrsafe: like uvm_km_pgremove(), but for non object backed
    *    regions.
    *
    * => when you unmap a part of anonymous kernel memory you want to toss
    *    the pages right away.    (this is called from uvm_unmap_...).
    * => none of the pages will ever be busy, and none of them will ever
    *    be on the active or inactive queues (because they have no object).
    */
   
   void
   uvm_km_pgremove_intrsafe(struct vm_map *map, vaddr_t start, vaddr_t end)
   {
   #define __PGRM_BATCH 16
           struct vm_page *pg;
           paddr_t pa[__PGRM_BATCH];
           int npgrm, i;
           vaddr_t va, batch_vastart;
   
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KASSERT(VM_MAP_IS_KERNEL(map));
           KASSERTMSG(vm_map_min(map) <= start,
               "vm_map_min(map) [%#"PRIxVADDR"] <= start [%#"PRIxVADDR"]"
               " (size=%#"PRIxVSIZE")",
               vm_map_min(map), start, end - start);
           KASSERT(start < end);
           KASSERT(end <= vm_map_max(map));
   
           for (va = start; va < end;) {
                   batch_vastart = va;
                   /* create a batch of at most __PGRM_BATCH pages to free */
                   for (i = 0;
                        i < __PGRM_BATCH && va < end;
                        va += PAGE_SIZE) {
                           if (!pmap_extract(pmap_kernel(), va, &pa[i])) {
                                   continue;
                           }
                           i++;
                   }
                   npgrm = i;
                   /* now remove the mappings */
                   pmap_kremove(batch_vastart, va - batch_vastart);
                   /* and free the pages */
                   for (i = 0; i < npgrm; i++) {
                           pg = PHYS_TO_VM_PAGE(pa[i]);
                           KASSERT(pg);
                           KASSERT(pg->uobject == NULL && pg->uanon == NULL);
                           KASSERT((pg->flags & PG_BUSY) == 0);
                           uvm_pagefree(pg);
                   }
           }
   #undef __PGRM_BATCH
   }
   
   #if defined(DEBUG)
   void
   uvm_km_check_empty(struct vm_map *map, vaddr_t start, vaddr_t end)
   {
           vaddr_t va;
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KDASSERT(VM_MAP_IS_KERNEL(map));
           KDASSERT(vm_map_min(map) <= start);
           KDASSERT(start < end);
           KDASSERT(end <= vm_map_max(map));
   
           for (va = start; va < end; va += PAGE_SIZE) {
                   paddr_t pa;
   
                   if (pmap_extract(pmap_kernel(), va, &pa)) {
                           panic("uvm_km_check_empty: va %p has pa %#llx",
                               (void *)va, (long long)pa);
                   }
                   /*
                    * kernel_object should not have pages for the corresponding
                    * region.  check it.
                    *
                    * why trylock?  because:
                    * - caller might not want to block.
                    * - we can recurse when allocating radix_node for
                    *   kernel_object.
                    */
                   if (rw_tryenter(uvm_kernel_object->vmobjlock, RW_READER)) {
                           struct vm_page *pg;
   
                           pg = uvm_pagelookup(uvm_kernel_object,
                               va - vm_map_min(kernel_map));
                           rw_exit(uvm_kernel_object->vmobjlock);
                           if (pg) {
                                   panic("uvm_km_check_empty: "
                                       "has page hashed at %p",
                                       (const void *)va);
                           }
                   }
           }
   }
   #endif /* defined(DEBUG) */
   
   /*
    * uvm_km_alloc: allocate an area of kernel memory.
    *
    * => NOTE: we can return 0 even if we can wait if there is not enough
    *      free VM space in the map... caller should be prepared to handle
    *      this case.
    * => we return KVA of memory allocated
    */
   
   vaddr_t
   uvm_km_alloc(struct vm_map *map, vsize_t size, vsize_t align, uvm_flag_t flags)
   {
           vaddr_t kva, loopva;
           vaddr_t offset;
           vsize_t loopsize;
           struct vm_page *pg;
           struct uvm_object *obj;
           int pgaflags;
           vm_prot_t prot, vaprot;
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KASSERT(vm_map_pmap(map) == pmap_kernel());
           KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED ||
                   (flags & UVM_KMF_TYPEMASK) == UVM_KMF_PAGEABLE ||
                   (flags & UVM_KMF_TYPEMASK) == UVM_KMF_VAONLY);
           KASSERT((flags & UVM_KMF_VAONLY) != 0 || (flags & UVM_KMF_COLORMATCH) == 0);
           KASSERT((flags & UVM_KMF_COLORMATCH) == 0 || (flags & UVM_KMF_VAONLY) != 0);
   
           /*
            * setup for call
            */
   
           kva = vm_map_min(map);  /* hint */
           size = round_page(size);
           obj = (flags & UVM_KMF_PAGEABLE) ? uvm_kernel_object : NULL;
           UVMHIST_LOG(maphist,"  (map=%#jx, obj=%#jx, size=%#jx, flags=%#jx)",
               (uintptr_t)map, (uintptr_t)obj, size, flags);
   
           /*
            * allocate some virtual space
            */
   
           vaprot = (flags & UVM_KMF_EXEC) ? UVM_PROT_ALL : UVM_PROT_RW;
           if (__predict_false(uvm_map(map, &kva, size, obj, UVM_UNKNOWN_OFFSET,
               align, UVM_MAPFLAG(vaprot, UVM_PROT_ALL, UVM_INH_NONE,
               UVM_ADV_RANDOM,
               (flags & (UVM_KMF_TRYLOCK | UVM_KMF_NOWAIT | UVM_KMF_WAITVA
                | UVM_KMF_COLORMATCH)))) != 0)) {
                   UVMHIST_LOG(maphist, "<- done (no VM)",0,0,0,0);
                   return(0);
           }
   
           /*
            * if all we wanted was VA, return now
            */
   
           if (flags & (UVM_KMF_VAONLY | UVM_KMF_PAGEABLE)) {
                   UVMHIST_LOG(maphist,"<- done valloc (kva=%#jx)", kva,0,0,0);
                   return(kva);
           }
   
           /*
            * recover object offset from virtual address
            */
   
           offset = kva - vm_map_min(kernel_map);
           UVMHIST_LOG(maphist, "  kva=%#jx, offset=%#jx", kva, offset,0,0);
   
           /*
            * now allocate and map in the memory... note that we are the only ones
            * whom should ever get a handle on this area of VM.
            */
   
           loopva = kva;
           loopsize = size;
   
           pgaflags = UVM_FLAG_COLORMATCH;
           if (flags & UVM_KMF_NOWAIT)
                   pgaflags |= UVM_PGA_USERESERVE;
           if (flags & UVM_KMF_ZERO)
                   pgaflags |= UVM_PGA_ZERO;
           prot = VM_PROT_READ | VM_PROT_WRITE;
           if (flags & UVM_KMF_EXEC)
                   prot |= VM_PROT_EXECUTE;
           while (loopsize) {
                   KASSERTMSG(!pmap_extract(pmap_kernel(), loopva, NULL),
                       "loopva=%#"PRIxVADDR, loopva);
   
                   pg = uvm_pagealloc_strat(NULL, offset, NULL, pgaflags,
   #ifdef UVM_KM_VMFREELIST
                      UVM_PGA_STRAT_ONLY, UVM_KM_VMFREELIST
   #else
                      UVM_PGA_STRAT_NORMAL, 0
   #endif
                      );
   
                   /*
                    * out of memory?
                    */
   
                   if (__predict_false(pg == NULL)) {
                           if ((flags & UVM_KMF_NOWAIT) ||
                               ((flags & UVM_KMF_CANFAIL) && !uvm_reclaimable())) {
                                   /* free everything! */
                                   uvm_km_free(map, kva, size,
                                       flags & UVM_KMF_TYPEMASK);
                                   return (0);
                           } else {
                                   uvm_wait("km_getwait2");        /* sleep here */
                                   continue;
                           }
                   }
   
                   pg->flags &= ~PG_BUSY;  /* new page */
                   UVM_PAGE_OWN(pg, NULL);
   
                   /*
                    * map it in
                    */
   
                   pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg),
                       prot, PMAP_KMPAGE);
                   loopva += PAGE_SIZE;
                   offset += PAGE_SIZE;
                   loopsize -= PAGE_SIZE;
           }
   
           pmap_update(pmap_kernel());
   
           if ((flags & UVM_KMF_ZERO) == 0) {
                   kmsan_orig((void *)kva, size, KMSAN_TYPE_UVM, __RET_ADDR);
                   kmsan_mark((void *)kva, size, KMSAN_STATE_UNINIT);
           }
   
           UVMHIST_LOG(maphist,"<- done (kva=%#jx)", kva,0,0,0);
           return(kva);
   }
   
   /*
    * uvm_km_protect: change the protection of an allocated area
    */
   
   int
   uvm_km_protect(struct vm_map *map, vaddr_t addr, vsize_t size, vm_prot_t prot)
   {
           return uvm_map_protect(map, addr, addr + round_page(size), prot, false);
   }
   
   /*
    * uvm_km_free: free an area of kernel memory
    */
   
   void
   uvm_km_free(struct vm_map *map, vaddr_t addr, vsize_t size, uvm_flag_t flags)
   {
           UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
   
           KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED ||
                   (flags & UVM_KMF_TYPEMASK) == UVM_KMF_PAGEABLE ||
                   (flags & UVM_KMF_TYPEMASK) == UVM_KMF_VAONLY);
           KASSERT((addr & PAGE_MASK) == 0);
           KASSERT(vm_map_pmap(map) == pmap_kernel());
   
           size = round_page(size);
   
           if (flags & UVM_KMF_PAGEABLE) {
                   uvm_km_pgremove(addr, addr + size);
           } else if (flags & UVM_KMF_WIRED) {
                   /*
                    * Note: uvm_km_pgremove_intrsafe() extracts mapping, thus
                    * remove it after.  See comment below about KVA visibility.
                    */
                   uvm_km_pgremove_intrsafe(map, addr, addr + size);
           }
   
           /*
            * Note: uvm_unmap_remove() calls pmap_update() for us, before
            * KVA becomes globally available.
            */
   
           uvm_unmap1(map, addr, addr + size, UVM_FLAG_VAONLY);
   }
   
   /* Sanity; must specify both or none. */
   #if (defined(PMAP_MAP_POOLPAGE) || defined(PMAP_UNMAP_POOLPAGE)) && \
       (!defined(PMAP_MAP_POOLPAGE) || !defined(PMAP_UNMAP_POOLPAGE))
   #error Must specify MAP and UNMAP together.
   #endif
   
   #if defined(PMAP_ALLOC_POOLPAGE) && \
       !defined(PMAP_MAP_POOLPAGE) && !defined(PMAP_UNMAP_POOLPAGE)
   #error Must specify ALLOC with MAP and UNMAP
   #endif
   
   int
   uvm_km_kmem_alloc(vmem_t *vm, vmem_size_t size, vm_flag_t flags,
       vmem_addr_t *addr)
   {
           struct vm_page *pg;
           vmem_addr_t va;
           int rc;
           vaddr_t loopva;
           vsize_t loopsize;
   
           size = round_page(size);
   
   #if defined(PMAP_MAP_POOLPAGE)
           if (size == PAGE_SIZE) {
   again:
   #ifdef PMAP_ALLOC_POOLPAGE
                   pg = PMAP_ALLOC_POOLPAGE((flags & VM_SLEEP) ?
                      0 : UVM_PGA_USERESERVE);
   #else
                   pg = uvm_pagealloc(NULL, 0, NULL,
                      (flags & VM_SLEEP) ? 0 : UVM_PGA_USERESERVE);
   #endif /* PMAP_ALLOC_POOLPAGE */
                   if (__predict_false(pg == NULL)) {
                           if (flags & VM_SLEEP) {
                                   uvm_wait("plpg");
                                   goto again;
                           }
                           return ENOMEM;
                   }
                   va = PMAP_MAP_POOLPAGE(VM_PAGE_TO_PHYS(pg));
                   KASSERT(va != 0);
                   *addr = va;
                   return 0;
           }
   #endif /* PMAP_MAP_POOLPAGE */
   
           rc = vmem_alloc(vm, size, flags, &va);
           if (rc != 0)
                   return rc;
   
   #ifdef PMAP_GROWKERNEL
           /*
            * These VA allocations happen independently of uvm_map
            * so this allocation must not extend beyond the current limit.
            */
           KASSERTMSG(uvm_maxkaddr >= va + size,
               "%#"PRIxVADDR" %#"PRIxPTR" %#zx",
               uvm_maxkaddr, va, size);
   #endif
   
           loopva = va;
           loopsize = size;
   
           while (loopsize) {
                   paddr_t pa __diagused;
                   KASSERTMSG(!pmap_extract(pmap_kernel(), loopva, &pa),
                       "loopva=%#"PRIxVADDR" loopsize=%#"PRIxVSIZE
                       " pa=%#"PRIxPADDR" vmem=%p",
                       loopva, loopsize, pa, vm);
   
                   pg = uvm_pagealloc(NULL, loopva, NULL,
                       UVM_FLAG_COLORMATCH
                       | ((flags & VM_SLEEP) ? 0 : UVM_PGA_USERESERVE));
                   if (__predict_false(pg == NULL)) {
                           if (flags & VM_SLEEP) {
                                   uvm_wait("plpg");
                                   continue;
                           } else {
                                   uvm_km_pgremove_intrsafe(kernel_map, va,
                                       va + size);
                                   vmem_free(vm, va, size);
                                   return ENOMEM;
                           }
                   }
   
                   pg->flags &= ~PG_BUSY;  /* new page */
                   UVM_PAGE_OWN(pg, NULL);
                   pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg),
                       VM_PROT_READ|VM_PROT_WRITE, PMAP_KMPAGE);
   
                   loopva += PAGE_SIZE;
                   loopsize -= PAGE_SIZE;
           }
           pmap_update(pmap_kernel());
   
           *addr = va;
   
           return 0;
   }
   
   void
   uvm_km_kmem_free(vmem_t *vm, vmem_addr_t addr, size_t size)
   {
   
           size = round_page(size);
   #if defined(PMAP_UNMAP_POOLPAGE)
           if (size == PAGE_SIZE) {
                   paddr_t pa;
   
                   pa = PMAP_UNMAP_POOLPAGE(addr);
                   uvm_pagefree(PHYS_TO_VM_PAGE(pa));
                   return;
           }
   #endif /* PMAP_UNMAP_POOLPAGE */
           uvm_km_pgremove_intrsafe(kernel_map, addr, addr + size);
           pmap_update(pmap_kernel());
   
           vmem_free(vm, addr, size);
   }
   
   bool
   uvm_km_va_starved_p(void)
   {
           vmem_size_t total;
           vmem_size_t free;
   
           if (kmem_arena == NULL)
                   return false;
   
           total = vmem_size(kmem_arena, VMEM_ALLOC|VMEM_FREE);
           free = vmem_size(kmem_arena, VMEM_FREE);
   
           return (free < (total / 10));
   }

Cache object: 01a47146f241b63572a67f888af12397