sys/dev/drm/linux_vmalloc.c

   1 /*
   2  * Copyright (c) 2017-2018 François Tigeot <ftigeot@wolfpond.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/_null.h>
  28 #include <sys/queue.h>
  29 #include <vm/vm_extern.h>
  30
  31 #include <linux/vmalloc.h>
  32 #include <linux/slab.h>
  33 #include <linux/mm.h>
  34
  35 struct vmap {
  36         void *addr;
  37         int npages;
  38         SLIST_ENTRY(vmap) vm_vmaps;
  39 };
  40
  41 SLIST_HEAD(vmap_list_head, vmap) vmap_list = SLIST_HEAD_INITIALIZER(vmap_list);
  42
  43 /* vmap: map an array of pages into virtually contiguous space */
  44 void *
  45 vmap(struct page **pages, unsigned int count,
  46         unsigned long flags, unsigned long prot)
  47 {
  48         struct vmap *vmp;
  49         vm_offset_t off;
  50         size_t size;
  51
  52         vmp = kmalloc(sizeof(struct vmap), M_DRM, M_WAITOK | M_ZERO);
  53
  54         size = count * PAGE_SIZE;
  55         off = kmem_alloc_nofault(&kernel_map, size,
  56                                  VM_SUBSYS_DRM_VMAP, PAGE_SIZE);
  57         if (off == 0)
  58                 return (NULL);
  59
  60         vmp->addr = (void *)off;
  61         vmp->npages = count;
  62         pmap_qenter(off, (struct vm_page **)pages, count);
  63         SLIST_INSERT_HEAD(&vmap_list, vmp, vm_vmaps);
  64
  65         return (void *)off;
  66 }
  67
  68 void
  69 vunmap(const void *addr)
  70 {
  71         struct vmap *vmp, *tmp_vmp;
  72         size_t size;
  73
  74         SLIST_FOREACH_MUTABLE(vmp, &vmap_list, vm_vmaps, tmp_vmp) {
  75                 if (vmp->addr == addr) {
  76                         size = vmp->npages * PAGE_SIZE;
  77
  78                         pmap_qremove((vm_offset_t)addr, vmp->npages);
  79                         kmem_free(&kernel_map, (vm_offset_t)addr, size);
  80                         goto found;
  81                 }
  82         }
  83
  84 found:
  85         SLIST_REMOVE(&vmap_list, vmp, vmap, vm_vmaps);
  86         kfree(vmp);
  87 }
  88
  89 int
  90 is_vmalloc_addr(const void *x)
  91 {
  92         struct vmap *vmp, *tmp_vmp;
  93
  94         SLIST_FOREACH_MUTABLE(vmp, &vmap_list, vm_vmaps, tmp_vmp) {
  95                 if (vmp->addr == x)
  96                         return 1;
  97         }
  98
  99         return false;
 100 }
 101
 102 /* allocate zeroed virtually contiguous memory for userspace */
 103 void *
 104 vmalloc_user(unsigned long size)
 105 {
 106         return kmalloc(size, M_DRM, M_WAITOK | M_ZERO);
 107 }
 108
 109 void
 110 vfree(const void *addr)
 111 {
 112         void *nc_addr;
 113
 114         memcpy(&nc_addr, &addr, sizeof(void *));
 115         kfree(nc_addr);
 116 }