1 /* $NetBSD: kfd_pasid.c,v 1.2 2018/08/27 04:58:20 riastradh Exp $ */ 2 3 /* 4 * Copyright 2014 Advanced Micro Devices, Inc. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 22 * OTHER DEALINGS IN THE SOFTWARE. 23 */ 24 25 #include <sys/cdefs.h> 26 __KERNEL_RCSID(0, "$NetBSD: kfd_pasid.c,v 1.2 2018/08/27 04:58:20 riastradh Exp $"); 27 28 #include <linux/slab.h> 29 #include <linux/types.h> 30 #include "kfd_priv.h" 31 32 static unsigned long *pasid_bitmap; 33 static unsigned int pasid_limit; 34 static DEFINE_MUTEX(pasid_mutex); 35 36 int kfd_pasid_init(void) 37 { 38 pasid_limit = KFD_MAX_NUM_OF_PROCESSES; 39 40 pasid_bitmap = kcalloc(BITS_TO_LONGS(pasid_limit), sizeof(long), GFP_KERNEL); 41 if (!pasid_bitmap) 42 return -ENOMEM; 43 44 set_bit(0, pasid_bitmap); /* PASID 0 is reserved. */ 45 46 return 0; 47 } 48 49 void kfd_pasid_exit(void) 50 { 51 kfree(pasid_bitmap); 52 } 53 54 bool kfd_set_pasid_limit(unsigned int new_limit) 55 { 56 if (new_limit < pasid_limit) { 57 bool ok; 58 59 mutex_lock(&pasid_mutex); 60 61 /* ensure that no pasids >= new_limit are in-use */ 62 ok = (find_next_bit(pasid_bitmap, pasid_limit, new_limit) == 63 pasid_limit); 64 if (ok) 65 pasid_limit = new_limit; 66 67 mutex_unlock(&pasid_mutex); 68 69 return ok; 70 } 71 72 return true; 73 } 74 75 inline unsigned int kfd_get_pasid_limit(void) 76 { 77 return pasid_limit; 78 } 79 80 unsigned int kfd_pasid_alloc(void) 81 { 82 unsigned int found; 83 84 mutex_lock(&pasid_mutex); 85 86 found = find_first_zero_bit(pasid_bitmap, pasid_limit); 87 if (found == pasid_limit) 88 found = 0; 89 else 90 set_bit(found, pasid_bitmap); 91 92 mutex_unlock(&pasid_mutex); 93 94 return found; 95 } 96 97 void kfd_pasid_free(unsigned int pasid) 98 { 99 BUG_ON(pasid == 0 || pasid >= pasid_limit); 100 clear_bit(pasid, pasid_bitmap); 101 } 102