1 /* $NetBSD: mm.c,v 1.19 2014/07/25 08:10:35 dholland Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2008, 2010 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas, Joerg Sonnenberger and Mindaugas Rasiukevicius. 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 /* 33 * Special /dev/{mem,kmem,zero,null} memory devices. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: mm.c,v 1.19 2014/07/25 08:10:35 dholland Exp $"); 38 39 #include "opt_compat_netbsd.h" 40 41 #include <sys/param.h> 42 #include <sys/conf.h> 43 #include <sys/ioctl.h> 44 #include <sys/mman.h> 45 #include <sys/uio.h> 46 #include <sys/termios.h> 47 48 #include <dev/mm.h> 49 50 #include <uvm/uvm_extern.h> 51 52 static void * dev_zero_page __read_mostly; 53 static kmutex_t dev_mem_lock __cacheline_aligned; 54 static vaddr_t dev_mem_addr __read_mostly; 55 56 static dev_type_read(mm_readwrite); 57 static dev_type_ioctl(mm_ioctl); 58 static dev_type_mmap(mm_mmap); 59 static dev_type_ioctl(mm_ioctl); 60 61 const struct cdevsw mem_cdevsw = { 62 #ifdef __HAVE_MM_MD_OPEN 63 .d_open = mm_md_open, 64 #else 65 .d_open = nullopen, 66 #endif 67 .d_close = nullclose, 68 .d_read = mm_readwrite, 69 .d_write = mm_readwrite, 70 .d_ioctl = mm_ioctl, 71 .d_stop = nostop, 72 .d_tty = notty, 73 .d_poll = nopoll, 74 .d_mmap = mm_mmap, 75 .d_kqfilter = nokqfilter, 76 .d_discard = nodiscard, 77 .d_flag = D_MPSAFE 78 }; 79 80 #ifdef pmax /* XXX */ 81 const struct cdevsw mem_ultrix_cdevsw = { 82 .d_open = nullopen, 83 .d_close = nullclose, 84 .d_read = mm_readwrite, 85 .d_write = mm_readwrite, 86 .d_ioctl = mm_ioctl, 87 .d_stop = nostop, 88 .d_tty = notty, 89 .d_poll = nopoll, 90 .d_mmap = mm_mmap, 91 .d_kqfilter = nokqfilter, 92 .d_discard = nodiscard, 93 .d_flag = D_MPSAFE 94 }; 95 #endif 96 97 /* 98 * mm_init: initialize memory device driver. 99 */ 100 void 101 mm_init(void) 102 { 103 vaddr_t pg; 104 105 mutex_init(&dev_mem_lock, MUTEX_DEFAULT, IPL_NONE); 106 107 /* Read-only zero-page. */ 108 pg = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); 109 KASSERT(pg != 0); 110 pmap_protect(pmap_kernel(), pg, pg + PAGE_SIZE, VM_PROT_READ); 111 pmap_update(pmap_kernel()); 112 dev_zero_page = (void *)pg; 113 114 #ifndef __HAVE_MM_MD_CACHE_ALIASING 115 /* KVA for mappings during I/O. */ 116 dev_mem_addr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 117 UVM_KMF_VAONLY|UVM_KMF_WAITVA); 118 KASSERT(dev_mem_addr != 0); 119 #else 120 dev_mem_addr = 0; 121 #endif 122 } 123 124 125 /* 126 * dev_mem_getva: get a special virtual address. If architecture requires, 127 * allocate VA according to PA, which avoids cache-aliasing issues. Use a 128 * constant, general mapping address otherwise. 129 */ 130 static inline vaddr_t 131 dev_mem_getva(paddr_t pa) 132 { 133 #ifdef __HAVE_MM_MD_CACHE_ALIASING 134 return uvm_km_alloc(kernel_map, PAGE_SIZE, 135 atop(pa) & uvmexp.colormask, 136 UVM_KMF_VAONLY | UVM_KMF_WAITVA | UVM_KMF_COLORMATCH); 137 #else 138 return dev_mem_addr; 139 #endif 140 } 141 142 static inline void 143 dev_mem_relva(paddr_t pa, vaddr_t va) 144 { 145 #ifdef __HAVE_MM_MD_CACHE_ALIASING 146 uvm_km_free(kernel_map, va, PAGE_SIZE, UVM_KMF_VAONLY); 147 #else 148 KASSERT(dev_mem_addr == va); 149 #endif 150 } 151 152 /* 153 * dev_kmem_readwrite: helper for DEV_MEM (/dev/mem) case of R/W. 154 */ 155 static int 156 dev_mem_readwrite(struct uio *uio, struct iovec *iov) 157 { 158 paddr_t paddr; 159 vaddr_t vaddr; 160 vm_prot_t prot; 161 size_t len, offset; 162 bool have_direct; 163 int error; 164 165 /* Check for wrap around. */ 166 if ((intptr_t)uio->uio_offset != uio->uio_offset) { 167 return EFAULT; 168 } 169 paddr = uio->uio_offset & ~PAGE_MASK; 170 prot = (uio->uio_rw == UIO_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 171 error = mm_md_physacc(paddr, prot); 172 if (error) { 173 return error; 174 } 175 offset = uio->uio_offset & PAGE_MASK; 176 len = MIN(uio->uio_resid, PAGE_SIZE - offset); 177 178 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS 179 /* Is physical address directly mapped? Return VA. */ 180 have_direct = mm_md_direct_mapped_phys(paddr, &vaddr); 181 #else 182 vaddr = 0; 183 have_direct = false; 184 #endif 185 if (!have_direct) { 186 /* Get a special virtual address. */ 187 const vaddr_t va = dev_mem_getva(paddr); 188 189 /* Map selected KVA to physical address. */ 190 mutex_enter(&dev_mem_lock); 191 pmap_kenter_pa(va, paddr, prot, 0); 192 pmap_update(pmap_kernel()); 193 194 /* Perform I/O. */ 195 vaddr = va + offset; 196 error = uiomove((void *)vaddr, len, uio); 197 198 /* Unmap, flush before unlock. */ 199 pmap_kremove(va, PAGE_SIZE); 200 pmap_update(pmap_kernel()); 201 mutex_exit(&dev_mem_lock); 202 203 /* "Release" the virtual address. */ 204 dev_mem_relva(paddr, va); 205 } else { 206 /* Direct map, just perform I/O. */ 207 vaddr += offset; 208 error = uiomove((void *)vaddr, len, uio); 209 } 210 return error; 211 } 212 213 /* 214 * dev_kmem_readwrite: helper for DEV_KMEM (/dev/kmem) case of R/W. 215 */ 216 static int 217 dev_kmem_readwrite(struct uio *uio, struct iovec *iov) 218 { 219 void *addr; 220 size_t len, offset; 221 vm_prot_t prot; 222 int error; 223 bool md_kva; 224 225 /* Check for wrap around. */ 226 addr = (void *)(intptr_t)uio->uio_offset; 227 if ((uintptr_t)addr != uio->uio_offset) { 228 return EFAULT; 229 } 230 /* 231 * Handle non-page aligned offset. 232 * Otherwise, we operate in page-by-page basis. 233 */ 234 offset = uio->uio_offset & PAGE_MASK; 235 len = MIN(uio->uio_resid, PAGE_SIZE - offset); 236 prot = (uio->uio_rw == UIO_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 237 238 md_kva = false; 239 240 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_IO 241 paddr_t paddr; 242 /* MD case: is this is a directly mapped address? */ 243 if (mm_md_direct_mapped_io(addr, &paddr)) { 244 /* If so, validate physical address. */ 245 error = mm_md_physacc(paddr, prot); 246 if (error) { 247 return error; 248 } 249 md_kva = true; 250 } 251 #endif 252 if (!md_kva) { 253 bool checked = false; 254 255 #ifdef __HAVE_MM_MD_KERNACC 256 /* MD check for the address. */ 257 error = mm_md_kernacc(addr, prot, &checked); 258 if (error) { 259 return error; 260 } 261 #endif 262 /* UVM check for the address (unless MD indicated to not). */ 263 if (!checked && !uvm_kernacc(addr, len, prot)) { 264 return EFAULT; 265 } 266 } 267 error = uiomove(addr, len, uio); 268 return error; 269 } 270 271 /* 272 * dev_zero_readwrite: helper for DEV_ZERO (/dev/null) case of R/W. 273 */ 274 static inline int 275 dev_zero_readwrite(struct uio *uio, struct iovec *iov) 276 { 277 size_t len; 278 279 /* Nothing to do for the write case. */ 280 if (uio->uio_rw == UIO_WRITE) { 281 uio->uio_resid = 0; 282 return 0; 283 } 284 /* 285 * Read in page-by-page basis, caller will continue. 286 * Cut appropriately for a single/last-iteration cases. 287 */ 288 len = MIN(iov->iov_len, PAGE_SIZE); 289 return uiomove(dev_zero_page, len, uio); 290 } 291 292 /* 293 * mm_readwrite: general memory R/W function. 294 */ 295 static int 296 mm_readwrite(dev_t dev, struct uio *uio, int flags) 297 { 298 struct iovec *iov; 299 int error; 300 301 #ifdef __HAVE_MM_MD_READWRITE 302 /* If defined - there are extra MD cases. */ 303 switch (minor(dev)) { 304 case DEV_MEM: 305 case DEV_KMEM: 306 case DEV_NULL: 307 case DEV_ZERO: 308 #if defined(COMPAT_16) && defined(__arm) 309 case _DEV_ZERO_oARM: 310 #endif 311 break; 312 default: 313 return mm_md_readwrite(dev, uio); 314 } 315 #endif 316 error = 0; 317 while (uio->uio_resid > 0 && error == 0) { 318 iov = uio->uio_iov; 319 if (iov->iov_len == 0) { 320 /* Processed; next I/O vector. */ 321 uio->uio_iov++; 322 uio->uio_iovcnt--; 323 KASSERT(uio->uio_iovcnt >= 0); 324 continue; 325 } 326 /* Helper functions will process in page-by-page basis. */ 327 switch (minor(dev)) { 328 case DEV_MEM: 329 error = dev_mem_readwrite(uio, iov); 330 break; 331 case DEV_KMEM: 332 error = dev_kmem_readwrite(uio, iov); 333 break; 334 case DEV_NULL: 335 if (uio->uio_rw == UIO_WRITE) { 336 uio->uio_resid = 0; 337 } 338 /* Break directly out of the loop. */ 339 return 0; 340 #if defined(COMPAT_16) && defined(__arm) 341 case _DEV_ZERO_oARM: 342 #endif 343 case DEV_ZERO: 344 error = dev_zero_readwrite(uio, iov); 345 break; 346 default: 347 error = ENXIO; 348 break; 349 } 350 } 351 return error; 352 } 353 354 /* 355 * mm_mmap: general mmap() handler. 356 */ 357 static paddr_t 358 mm_mmap(dev_t dev, off_t off, int acc) 359 { 360 vm_prot_t prot; 361 362 #ifdef __HAVE_MM_MD_MMAP 363 /* If defined - there are extra mmap() MD cases. */ 364 switch (minor(dev)) { 365 case DEV_MEM: 366 case DEV_KMEM: 367 case DEV_NULL: 368 #if defined(COMPAT_16) && defined(__arm) 369 case _DEV_ZERO_oARM: 370 #endif 371 case DEV_ZERO: 372 break; 373 default: 374 return mm_md_mmap(dev, off, acc); 375 } 376 #endif 377 /* 378 * /dev/null does not make sense, /dev/kmem is volatile and 379 * /dev/zero is handled in mmap already. 380 */ 381 if (minor(dev) != DEV_MEM) { 382 return -1; 383 } 384 385 prot = 0; 386 if (acc & PROT_EXEC) 387 prot |= VM_PROT_EXECUTE; 388 if (acc & PROT_READ) 389 prot |= VM_PROT_READ; 390 if (acc & PROT_WRITE) 391 prot |= VM_PROT_WRITE; 392 393 /* Validate the physical address. */ 394 if (mm_md_physacc(off, prot) != 0) { 395 return -1; 396 } 397 return off >> PGSHIFT; 398 } 399 400 static int 401 mm_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 402 { 403 404 switch (cmd) { 405 case FIONBIO: 406 /* We never block anyway. */ 407 return 0; 408 409 case FIOSETOWN: 410 case FIOGETOWN: 411 case TIOCGPGRP: 412 case TIOCSPGRP: 413 case TIOCGETA: 414 return ENOTTY; 415 416 case FIOASYNC: 417 if ((*(int *)data) == 0) { 418 return 0; 419 } 420 /* FALLTHROUGH */ 421 default: 422 return EOPNOTSUPP; 423 } 424 } 425