drivers/gpu/drm/amd/amdkfd/kfd_pasid.c

   1 /*
   2  * Copyright 2014 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  */
  22
  23 #include <linux/slab.h>
  24 #include <linux/types.h>
  25 #include "kfd_priv.h"
  26
  27 static unsigned long *pasid_bitmap;
  28 static unsigned int pasid_limit;
  29 static DEFINE_MUTEX(pasid_mutex);
  30
  31 int kfd_pasid_init(void)
  32 {
  33         pasid_limit = KFD_MAX_NUM_OF_PROCESSES;
  34
  35         pasid_bitmap = kcalloc(BITS_TO_LONGS(pasid_limit), sizeof(long), GFP_KERNEL);
  36         if (!pasid_bitmap)
  37                 return -ENOMEM;
  38
  39         set_bit(0, pasid_bitmap); /* PASID 0 is reserved. */
  40
  41         return 0;
  42 }
  43
  44 void kfd_pasid_exit(void)
  45 {
  46         kfree(pasid_bitmap);
  47 }
  48
  49 bool kfd_set_pasid_limit(unsigned int new_limit)
  50 {
  51         if (new_limit < pasid_limit) {
  52                 bool ok;
  53
  54                 mutex_lock(&pasid_mutex);
  55
  56                 /* ensure that no pasids >= new_limit are in-use */
  57                 ok = (find_next_bit(pasid_bitmap, pasid_limit, new_limit) ==
  58                                                                 pasid_limit);
  59                 if (ok)
  60                         pasid_limit = new_limit;
  61
  62                 mutex_unlock(&pasid_mutex);
  63
  64                 return ok;
  65         }
  66
  67         return true;
  68 }
  69
  70 inline unsigned int kfd_get_pasid_limit(void)
  71 {
  72         return pasid_limit;
  73 }
  74
  75 unsigned int kfd_pasid_alloc(void)
  76 {
  77         unsigned int found;
  78
  79         mutex_lock(&pasid_mutex);
  80
  81         found = find_first_zero_bit(pasid_bitmap, pasid_limit);
  82         if (found == pasid_limit)
  83                 found = 0;
  84         else
  85                 set_bit(found, pasid_bitmap);
  86
  87         mutex_unlock(&pasid_mutex);
  88
  89         return found;
  90 }
  91
  92 void kfd_pasid_free(unsigned int pasid)
  93 {
  94         BUG_ON(pasid == 0 || pasid >= pasid_limit);
  95         clear_bit(pasid, pasid_bitmap);
  96 }