1 /* $NetBSD: linux_kmap.c,v 1.11 2014/11/04 11:27:31 jmcneill 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 1.11 2014/11/04 11:27:31 jmcneill Exp $"); 34 35 #include <sys/types.h> 36 #include <sys/kmem.h> 37 #include <sys/mutex.h> 38 #include <sys/rbtree.h> 39 40 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 41 #include <dev/mm.h> 42 #endif 43 44 #include <uvm/uvm_extern.h> 45 46 #include <linux/highmem.h> 47 48 /* 49 * XXX Kludgerific implementation of Linux kmap_atomic, which is 50 * required not to fail. To accomodate this, we reserve one page of 51 * kva at boot (or load) and limit the system to at most kmap_atomic in 52 * use at a time. 53 */ 54 55 static kmutex_t linux_kmap_atomic_lock; 56 static vaddr_t linux_kmap_atomic_vaddr; 57 58 static kmutex_t linux_kmap_lock; 59 static rb_tree_t linux_kmap_entries; 60 61 struct linux_kmap_entry { 62 paddr_t lke_paddr; 63 vaddr_t lke_vaddr; 64 unsigned int lke_refcnt; 65 rb_node_t lke_node; 66 }; 67 68 static int 69 lke_compare_nodes(void *ctx __unused, const void *an, const void *bn) 70 { 71 const struct linux_kmap_entry *const a = an; 72 const struct linux_kmap_entry *const b = bn; 73 74 if (a->lke_paddr < b->lke_paddr) 75 return -1; 76 else if (a->lke_paddr > b->lke_paddr) 77 return +1; 78 else 79 return 0; 80 } 81 82 static int 83 lke_compare_key(void *ctx __unused, const void *node, const void *key) 84 { 85 const struct linux_kmap_entry *const lke = node; 86 const paddr_t *const paddrp = key; 87 88 if (lke->lke_paddr < *paddrp) 89 return -1; 90 else if (lke->lke_paddr > *paddrp) 91 return +1; 92 else 93 return 0; 94 } 95 96 static const rb_tree_ops_t linux_kmap_entry_ops = { 97 .rbto_compare_nodes = &lke_compare_nodes, 98 .rbto_compare_key = &lke_compare_key, 99 .rbto_node_offset = offsetof(struct linux_kmap_entry, lke_node), 100 .rbto_context = NULL, 101 }; 102 103 int 104 linux_kmap_init(void) 105 { 106 107 /* IPL_SCHED since interrupt handlers use kmap_atomic. */ 108 mutex_init(&linux_kmap_atomic_lock, MUTEX_DEFAULT, IPL_SCHED); 109 110 linux_kmap_atomic_vaddr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 111 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 112 113 KASSERT(linux_kmap_atomic_vaddr != 0); 114 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 115 116 mutex_init(&linux_kmap_lock, MUTEX_DEFAULT, IPL_NONE); 117 rb_tree_init(&linux_kmap_entries, &linux_kmap_entry_ops); 118 119 return 0; 120 } 121 122 void 123 linux_kmap_fini(void) 124 { 125 126 KASSERT(RB_TREE_MIN(&linux_kmap_entries) == NULL); 127 #if 0 /* XXX no rb_tree_destroy */ 128 rb_tree_destroy(&linux_kmap_entries); 129 #endif 130 mutex_destroy(&linux_kmap_lock); 131 132 KASSERT(linux_kmap_atomic_vaddr != 0); 133 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 134 135 uvm_km_free(kernel_map, linux_kmap_atomic_vaddr, PAGE_SIZE, 136 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 137 138 mutex_destroy(&linux_kmap_atomic_lock); 139 } 140 141 void * 142 kmap_atomic(struct page *page) 143 { 144 const paddr_t paddr = uvm_vm_page_to_phys(&page->p_vmp); 145 vaddr_t vaddr; 146 147 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 148 if (mm_md_direct_mapped_phys(paddr, &vaddr)) 149 return (void *)vaddr; 150 #endif 151 152 mutex_spin_enter(&linux_kmap_atomic_lock); 153 KASSERT(linux_kmap_atomic_vaddr != 0); 154 KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL)); 155 vaddr = linux_kmap_atomic_vaddr; 156 pmap_kenter_pa(vaddr, paddr, (VM_PROT_READ | VM_PROT_WRITE), 0); 157 pmap_update(pmap_kernel()); 158 159 return (void *)vaddr; 160 } 161 162 void 163 kunmap_atomic(void *addr) 164 { 165 const vaddr_t vaddr = (vaddr_t)addr; 166 167 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 168 { 169 paddr_t paddr; 170 vaddr_t vaddr1; 171 bool ok __diagused; 172 173 ok = pmap_extract(pmap_kernel(), vaddr, &paddr); 174 KASSERT(ok); 175 if (mm_md_direct_mapped_phys(paddr, &vaddr1) && vaddr1 == vaddr) 176 return; 177 } 178 #endif 179 180 KASSERT(mutex_owned(&linux_kmap_atomic_lock)); 181 KASSERT(linux_kmap_atomic_vaddr == vaddr); 182 KASSERT(pmap_extract(pmap_kernel(), vaddr, NULL)); 183 184 pmap_kremove(vaddr, PAGE_SIZE); 185 pmap_update(pmap_kernel()); 186 187 mutex_spin_exit(&linux_kmap_atomic_lock); 188 } 189 190 void * 191 kmap(struct page *page) 192 { 193 const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp); 194 vaddr_t vaddr; 195 196 ASSERT_SLEEPABLE(); 197 198 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 199 if (mm_md_direct_mapped_phys(paddr, &vaddr)) 200 return (void *)vaddr; 201 #endif 202 203 vaddr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 204 (UVM_KMF_VAONLY | UVM_KMF_WAITVA)); 205 KASSERT(vaddr != 0); 206 207 struct linux_kmap_entry *const lke = kmem_alloc(sizeof(*lke), 208 KM_SLEEP); 209 lke->lke_paddr = paddr; 210 lke->lke_vaddr = vaddr; 211 212 mutex_enter(&linux_kmap_lock); 213 struct linux_kmap_entry *const collision __diagused = 214 rb_tree_insert_node(&linux_kmap_entries, lke); 215 KASSERT(collision == lke); 216 mutex_exit(&linux_kmap_lock); 217 218 KASSERT(!pmap_extract(pmap_kernel(), vaddr, NULL)); 219 pmap_kenter_pa(vaddr, paddr, (VM_PROT_READ | VM_PROT_WRITE), 0); 220 pmap_update(pmap_kernel()); 221 222 return (void *)vaddr; 223 } 224 225 void 226 kunmap(struct page *page) 227 { 228 const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp); 229 230 ASSERT_SLEEPABLE(); 231 232 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 233 { 234 vaddr_t vaddr1; 235 236 if (mm_md_direct_mapped_phys(paddr, &vaddr1)) 237 return; 238 } 239 #endif 240 241 mutex_enter(&linux_kmap_lock); 242 struct linux_kmap_entry *const lke = 243 rb_tree_find_node(&linux_kmap_entries, &paddr); 244 KASSERT(lke != NULL); 245 rb_tree_remove_node(&linux_kmap_entries, lke); 246 mutex_exit(&linux_kmap_lock); 247 248 const vaddr_t vaddr = lke->lke_vaddr; 249 kmem_free(lke, sizeof(*lke)); 250 251 KASSERT(pmap_extract(pmap_kernel(), vaddr, NULL)); 252 253 pmap_kremove(vaddr, PAGE_SIZE); 254 pmap_update(pmap_kernel()); 255 256 uvm_km_free(kernel_map, vaddr, PAGE_SIZE, UVM_KMF_VAONLY); 257 } 258