1 /* $NetBSD: linux_kmap.c,v 1.16 2018/08/27 15:28:53 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 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 __KERNEL_RCSID(0, "$NetBSD: linux_kmap.c,v 1.16 2018/08/27 15:28:53 riastradh Exp $"); 34 35 #include <sys/types.h> 36 #include <sys/kmem.h> 37 #include <sys/mutex.h> 38 #include <sys/rbtree.h> 39 #include <sys/sdt.h> 40 41 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 42 #include <dev/mm.h> 43 #endif 44 45 #include <uvm/uvm_extern.h> 46 47 #include <linux/highmem.h> 48 49 SDT_PROBE_DEFINE2(sdt, linux, kmap, map, 50 "paddr_t"/*paddr*/, "vaddr_t"/*vaddr*/); 51 SDT_PROBE_DEFINE2(sdt, linux, kmap, unmap, 52 "paddr_t"/*paddr*/, "vaddr_t"/*vaddr*/); 53 SDT_PROBE_DEFINE2(sdt, linux, kmap, map__atomic, 54 "paddr_t"/*paddr*/, "vaddr_t"/*vaddr*/); 55 SDT_PROBE_DEFINE2(sdt, linux, kmap, unmap__atomic, 56 "paddr_t"/*paddr*/, "vaddr_t"/*vaddr*/); 57 58 /* 59 * XXX Kludgerific implementation of Linux kmap_atomic, which is 60 * required not to fail. To accomodate this, we reserve one page of 61 * kva at boot (or load) and limit the system to at most kmap_atomic in 62 * use at a time. 63 */ 64 65 static kmutex_t linux_kmap_atomic_lock; 66 static vaddr_t linux_kmap_atomic_vaddr; 67 68 static kmutex_t linux_kmap_lock; 69 static rb_tree_t linux_kmap_entries; 70 71 struct linux_kmap_entry { 72 paddr_t lke_paddr; 73 vaddr_t lke_vaddr; 74 unsigned int lke_refcnt; 75 rb_node_t lke_node; 76 }; 77 78 static int 79 lke_compare_nodes(void *ctx __unused, const void *an, const void *bn) 80 { 81 const struct linux_kmap_entry *const a = an; 82 const struct linux_kmap_entry *const b = bn; 83 84 if (a->lke_paddr < b->lke_paddr) 85 return -1; 86 else if (a->lke_paddr > b->lke_paddr) 87 return +1; 88 else 89 return 0; 90 } 91 92 static int 93 lke_compare_key(void *ctx __unused, const void *node, const void *key) 94 { 95 const struct linux_kmap_entry *const lke = node; 96 const paddr_t *const paddrp = key; 97 98 if (lke->lke_paddr < *paddrp) 99 return -1; 100 else if (lke->lke_paddr > *paddrp) 101 return +1; 102 else 103 return 0; 104 } 105 106 static const rb_tree_ops_t linux_kmap_entry_ops = { 107 .rbto_compare_nodes = &lke_compare_nodes, 108 .rbto_compare_key = &lke_compare_key, 109 .rbto_node_offset = offsetof(struct linux_kmap_entry, lke_node), 110 .rbto_context = NULL, 111 }; 112 113 int 114 linux_kmap_init(void) 115 { 116 117 /* IPL_VM since interrupt handlers use kmap_atomic. */ 118 mutex_init(&linux_kmap_atomic_lock, MUTEX_DEFAULT, IPL_VM); 119 120 linux_kmap_atomic_vaddr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 121 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 122 123 KASSERT(linux_kmap_atomic_vaddr != 0); 124 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 125 126 mutex_init(&linux_kmap_lock, MUTEX_DEFAULT, IPL_NONE); 127 rb_tree_init(&linux_kmap_entries, &linux_kmap_entry_ops); 128 129 return 0; 130 } 131 132 void 133 linux_kmap_fini(void) 134 { 135 136 KASSERT(RB_TREE_MIN(&linux_kmap_entries) == NULL); 137 #if 0 /* XXX no rb_tree_destroy */ 138 rb_tree_destroy(&linux_kmap_entries); 139 #endif 140 mutex_destroy(&linux_kmap_lock); 141 142 KASSERT(linux_kmap_atomic_vaddr != 0); 143 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 144 145 uvm_km_free(kernel_map, linux_kmap_atomic_vaddr, PAGE_SIZE, 146 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 147 148 mutex_destroy(&linux_kmap_atomic_lock); 149 } 150 151 void * 152 kmap_atomic(struct page *page) 153 { 154 const paddr_t paddr = uvm_vm_page_to_phys(&page->p_vmp); 155 vaddr_t vaddr; 156 157 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 158 if (mm_md_direct_mapped_phys(paddr, &vaddr)) 159 goto out; 160 #endif 161 162 mutex_spin_enter(&linux_kmap_atomic_lock); 163 KASSERT(linux_kmap_atomic_vaddr != 0); 164 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 165 vaddr = linux_kmap_atomic_vaddr; 166 pmap_kenter_pa(vaddr, paddr, (VM_PROT_READ | VM_PROT_WRITE), 0); 167 pmap_update(pmap_kernel()); 168 169 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 170 out: 171 #endif 172 SDT_PROBE2(sdt, linux, kmap, map__atomic, paddr, vaddr); 173 return (void *)vaddr; 174 } 175 176 void 177 kunmap_atomic(void *addr) 178 { 179 const vaddr_t vaddr = (vaddr_t)addr; 180 paddr_t paddr; 181 bool ok __diagused; 182 183 ok = pmap_extract(pmap_kernel(), vaddr, &paddr); 184 KASSERT(ok); 185 186 SDT_PROBE2(sdt, linux, kmap, unmap__atomic, paddr, vaddr); 187 188 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 189 { 190 vaddr_t vaddr1; 191 if (mm_md_direct_mapped_phys(paddr, &vaddr1) && vaddr1 == vaddr) 192 return; 193 } 194 #endif 195 196 KASSERT(mutex_owned(&linux_kmap_atomic_lock)); 197 KASSERT(linux_kmap_atomic_vaddr == vaddr); 198 199 pmap_kremove(vaddr, PAGE_SIZE); 200 pmap_update(pmap_kernel()); 201 202 mutex_spin_exit(&linux_kmap_atomic_lock); 203 } 204 205 void * 206 kmap(struct page *page) 207 { 208 const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp); 209 vaddr_t vaddr; 210 211 ASSERT_SLEEPABLE(); 212 213 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 214 if (mm_md_direct_mapped_phys(paddr, &vaddr)) 215 goto out; 216 #endif 217 218 vaddr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 219 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 220 KASSERT(vaddr != 0); 221 222 struct linux_kmap_entry *const lke = kmem_alloc(sizeof(*lke), 223 KM_SLEEP); 224 lke->lke_paddr = paddr; 225 lke->lke_vaddr = vaddr; 226 227 mutex_enter(&linux_kmap_lock); 228 struct linux_kmap_entry *const collision __diagused = 229 rb_tree_insert_node(&linux_kmap_entries, lke); 230 KASSERT(collision == lke); 231 mutex_exit(&linux_kmap_lock); 232 233 KASSERT(!pmap_extract(pmap_kernel(), vaddr, NULL)); 234 pmap_kenter_pa(vaddr, paddr, (VM_PROT_READ | VM_PROT_WRITE), 0); 235 pmap_update(pmap_kernel()); 236 237 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 238 out: 239 #endif 240 SDT_PROBE2(sdt, linux, kmap, map, paddr, vaddr); 241 return (void *)vaddr; 242 } 243 244 void 245 kunmap(struct page *page) 246 { 247 const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp); 248 vaddr_t vaddr; 249 250 ASSERT_SLEEPABLE(); 251 252 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 253 if (mm_md_direct_mapped_phys(paddr, &vaddr)) 254 goto out; 255 #endif 256 257 mutex_enter(&linux_kmap_lock); 258 struct linux_kmap_entry *const lke = 259 rb_tree_find_node(&linux_kmap_entries, &paddr); 260 KASSERT(lke != NULL); 261 rb_tree_remove_node(&linux_kmap_entries, lke); 262 mutex_exit(&linux_kmap_lock); 263 264 vaddr = lke->lke_vaddr; 265 kmem_free(lke, sizeof(*lke)); 266 267 KASSERT(pmap_extract(pmap_kernel(), vaddr, NULL)); 268 269 pmap_kremove(vaddr, PAGE_SIZE); 270 pmap_update(pmap_kernel()); 271 272 uvm_km_free(kernel_map, vaddr, PAGE_SIZE, UVM_KMF_VAONLY); 273 274 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 275 out: 276 #endif 277 SDT_PROBE2(sdt, linux, kmap, unmap, paddr, vaddr); 278 } 279
Indexes created Sun Sep 21 15:09:59 GMT 2025