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 } 97