1 /* $NetBSD: pmap_pvt.c,v 1.11 2021/07/21 06:35:45 skrll Exp $ */ 2 3 /*- 4 * Copyright (c) 2014, 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __RCSID("$NetBSD: pmap_pvt.c,v 1.11 2021/07/21 06:35:45 skrll Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/atomic.h> 37 #include <sys/kmem.h> 38 #include <sys/pserialize.h> 39 40 #include <uvm/uvm.h> 41 #include <uvm/pmap/pmap_pvt.h> 42 43 /* 44 * unmanaged pv-tracked ranges 45 * 46 * This is a linear list for now because the only user are the DRM 47 * graphics drivers, with a single tracked range per device, for the 48 * graphics aperture, so there are expected to be few of them. 49 * 50 * This is used only after the VM system is initialized well enough 51 * that we can use kmem_alloc. 52 */ 53 54 struct pv_track { 55 paddr_t pvt_start; 56 psize_t pvt_size; 57 struct pv_track *pvt_next; 58 struct pmap_page pvt_pages[]; 59 }; 60 61 static struct { 62 kmutex_t lock; 63 pserialize_t psz; 64 struct pv_track *list; 65 } pv_unmanaged __cacheline_aligned; 66 67 void 68 pmap_pv_init(void) 69 { 70 71 mutex_init(&pv_unmanaged.lock, MUTEX_DEFAULT, IPL_NONE); 72 pv_unmanaged.psz = pserialize_create(); 73 pv_unmanaged.list = NULL; 74 } 75 76 void 77 pmap_pv_track(paddr_t start, psize_t size) 78 { 79 struct pv_track *pvt; 80 size_t npages; 81 82 KASSERT(start == trunc_page(start)); 83 KASSERT(size == trunc_page(size)); 84 85 /* We may sleep for allocation. */ 86 ASSERT_SLEEPABLE(); 87 88 npages = size >> PAGE_SHIFT; 89 pvt = kmem_zalloc(offsetof(struct pv_track, pvt_pages[npages]), 90 KM_SLEEP); 91 pvt->pvt_start = start; 92 pvt->pvt_size = size; 93 94 #ifdef PMAP_PAGE_INIT 95 for (size_t i = 0; i < npages; i++) 96 PMAP_PAGE_INIT(&pvt->pvt_pages[i]); 97 #endif 98 99 mutex_enter(&pv_unmanaged.lock); 100 pvt->pvt_next = pv_unmanaged.list; 101 atomic_store_release(&pv_unmanaged.list, pvt); 102 mutex_exit(&pv_unmanaged.lock); 103 } 104 105 void 106 pmap_pv_untrack(paddr_t start, psize_t size) 107 { 108 struct pv_track **pvtp, *pvt; 109 size_t npages; 110 111 KASSERT(start == trunc_page(start)); 112 KASSERT(size == trunc_page(size)); 113 114 /* We may sleep for pserialize_perform. */ 115 ASSERT_SLEEPABLE(); 116 117 mutex_enter(&pv_unmanaged.lock); 118 for (pvtp = &pv_unmanaged.list; 119 (pvt = *pvtp) != NULL; 120 pvtp = &pvt->pvt_next) { 121 if (pvt->pvt_start != start) 122 continue; 123 if (pvt->pvt_size != size) 124 panic("pmap_pv_untrack: pv-tracking at 0x%"PRIxPADDR 125 ": 0x%"PRIxPSIZE" bytes, not 0x%"PRIxPSIZE" bytes", 126 pvt->pvt_start, pvt->pvt_size, size); 127 128 /* 129 * Remove from list. Readers can safely see the old 130 * and new states of the list. 131 */ 132 atomic_store_relaxed(pvtp, pvt->pvt_next); 133 134 /* Wait for readers who can see the old state to finish. */ 135 pserialize_perform(pv_unmanaged.psz); 136 137 /* 138 * We now have exclusive access to pvt and can destroy 139 * it. Poison it to catch bugs. 140 */ 141 explicit_memset(&pvt->pvt_next, 0x1a, sizeof pvt->pvt_next); 142 goto out; 143 } 144 panic("pmap_pv_untrack: pages not pv-tracked at 0x%"PRIxPADDR 145 " (0x%"PRIxPSIZE" bytes)", 146 start, size); 147 out: mutex_exit(&pv_unmanaged.lock); 148 149 npages = size >> PAGE_SHIFT; 150 kmem_free(pvt, offsetof(struct pv_track, pvt_pages[npages])); 151 } 152 153 struct pmap_page * 154 pmap_pv_tracked(paddr_t pa) 155 { 156 struct pv_track *pvt; 157 size_t pgno; 158 int s; 159 160 KASSERT(pa == trunc_page(pa)); 161 162 s = pserialize_read_enter(); 163 for (pvt = atomic_load_consume(&pv_unmanaged.list); 164 pvt != NULL; 165 pvt = pvt->pvt_next) { 166 if ((pvt->pvt_start <= pa) && 167 ((pa - pvt->pvt_start) < pvt->pvt_size)) 168 break; 169 } 170 pserialize_read_exit(s); 171 172 if (pvt == NULL) 173 return NULL; 174 KASSERT(pvt->pvt_start <= pa); 175 KASSERT((pa - pvt->pvt_start) < pvt->pvt_size); 176 pgno = (pa - pvt->pvt_start) >> PAGE_SHIFT; 177 return &pvt->pvt_pages[pgno]; 178 } 179 180