1 /* 2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/kern/kern_xio.c,v 1.16 2008/05/09 07:24:45 dillon Exp $ 35 */ 36 /* 37 * Kernel XIO interface. An initialized XIO is basically a collection of 38 * appropriately held vm_page_t's. XIO buffers are vmspace agnostic and 39 * can represent userspace or kernelspace buffers, and can be passed to 40 * foreign threads outside of the originating vmspace. XIO buffers are 41 * not mapped into KVM and thus can be manipulated and passed around with 42 * very low overheads. 43 * 44 * The intent is for XIO to be used in the I/O path, VFS, CAPS, and other 45 * places that need to pass (possibly userspace) data between threads. 46 * 47 * TODO: check for busy page when modifying, check writeable. 48 */ 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/malloc.h> 53 #include <sys/proc.h> 54 #include <sys/vmmeter.h> 55 #include <sys/vnode.h> 56 #include <sys/xio.h> 57 58 #include <cpu/lwbuf.h> 59 60 #include <vm/vm.h> 61 #include <vm/vm_param.h> 62 #include <sys/lock.h> 63 #include <vm/vm_kern.h> 64 #include <vm/pmap.h> 65 #include <vm/vm_map.h> 66 #include <vm/vm_object.h> 67 #include <vm/vm_page.h> 68 #include <vm/vm_pageout.h> 69 #include <vm/vm_pager.h> 70 #include <vm/vm_extern.h> 71 #include <vm/vm_page2.h> 72 73 /* 74 * Just do basic initialization of an empty XIO 75 */ 76 void 77 xio_init(xio_t xio) 78 { 79 xio->xio_flags = 0; 80 xio->xio_bytes = 0; 81 xio->xio_error = 0; 82 xio->xio_offset = 0; 83 xio->xio_npages = 0; 84 xio->xio_pages = xio->xio_internal_pages; 85 } 86 87 /* 88 * Initialize an XIO given a userspace buffer. 0 is returned on success, 89 * an error code on failure. The actual number of bytes that could be 90 * accomodated in the XIO will be stored in xio_bytes and the page offset 91 * will be stored in xio_offset. 92 */ 93 int 94 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags) 95 { 96 vm_offset_t addr; 97 vm_page_t m; 98 vm_page_t m0; 99 int error; 100 int i; 101 int n; 102 int vmprot; 103 104 addr = trunc_page((vm_offset_t)ubase); 105 xio->xio_flags = flags; 106 xio->xio_bytes = 0; 107 xio->xio_error = 0; 108 if (ubytes == 0) { 109 xio->xio_offset = 0; 110 xio->xio_npages = 0; 111 } else { 112 vmprot = (flags & XIOF_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 113 xio->xio_offset = (vm_offset_t)ubase & PAGE_MASK; 114 xio->xio_pages = xio->xio_internal_pages; 115 if ((n = PAGE_SIZE - xio->xio_offset) > ubytes) 116 n = ubytes; 117 m0 = NULL; 118 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) { 119 m = vm_fault_page_quick(addr, vmprot, &error); 120 if (m == NULL) 121 break; 122 xio->xio_pages[i] = m; 123 ubytes -= n; 124 xio->xio_bytes += n; 125 if ((n = ubytes) > PAGE_SIZE) 126 n = PAGE_SIZE; 127 addr += PAGE_SIZE; 128 129 /* 130 * Check linearity, used by syslink to memory map DMA buffers. 131 */ 132 if (flags & XIOF_VMLINEAR) { 133 if (i == 0) { 134 m0 = m; 135 } else 136 if (m->object != m0->object || m->pindex != m0->pindex + i) { 137 error = EINVAL; 138 break; 139 } 140 } 141 } 142 xio->xio_npages = i; 143 144 /* 145 * If a failure occured clean out what we loaded and return EFAULT. 146 * Return 0 on success. Do not dirty the pages. 147 */ 148 if (i < XIO_INTERNAL_PAGES && n) { 149 xio->xio_flags &= ~XIOF_WRITE; 150 xio_release(xio); 151 xio->xio_error = EFAULT; 152 } 153 } 154 return(xio->xio_error); 155 } 156 157 /* 158 * Initialize an XIO given a kernelspace buffer. 0 is returned on success, 159 * an error code on failure. The actual number of bytes that could be 160 * accomodated in the XIO will be stored in xio_bytes and the page offset 161 * will be stored in xio_offset. 162 */ 163 int 164 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes) 165 { 166 vm_offset_t addr; 167 vm_paddr_t paddr; 168 vm_page_t m; 169 int i; 170 int n; 171 172 addr = trunc_page((vm_offset_t)kbase); 173 xio->xio_flags = 0; 174 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK; 175 xio->xio_bytes = 0; 176 xio->xio_pages = xio->xio_internal_pages; 177 xio->xio_error = 0; 178 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes) 179 n = kbytes; 180 lwkt_gettoken(&vm_token); 181 crit_enter(); 182 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) { 183 if ((paddr = pmap_kextract(addr)) == 0) 184 break; 185 m = PHYS_TO_VM_PAGE(paddr); 186 vm_page_hold(m); 187 xio->xio_pages[i] = m; 188 kbytes -= n; 189 xio->xio_bytes += n; 190 if ((n = kbytes) > PAGE_SIZE) 191 n = PAGE_SIZE; 192 addr += PAGE_SIZE; 193 } 194 crit_exit(); 195 lwkt_reltoken(&vm_token); 196 xio->xio_npages = i; 197 198 /* 199 * If a failure occured clean out what we loaded and return EFAULT. 200 * Return 0 on success. 201 */ 202 if (i < XIO_INTERNAL_PAGES && n) { 203 xio_release(xio); 204 xio->xio_error = EFAULT; 205 } 206 return(xio->xio_error); 207 } 208 209 /* 210 * Initialize an XIO given an array of vm_page pointers. The caller is 211 * responsible for any modified state changes for the pages. 212 */ 213 int 214 xio_init_pages(xio_t xio, struct vm_page **mbase, int npages, int xflags) 215 { 216 int i; 217 218 KKASSERT(npages <= XIO_INTERNAL_PAGES); 219 220 xio->xio_flags = xflags; 221 xio->xio_offset = 0; 222 xio->xio_bytes = npages * PAGE_SIZE; 223 xio->xio_pages = xio->xio_internal_pages; 224 xio->xio_npages = npages; 225 xio->xio_error = 0; 226 lwkt_gettoken(&vm_token); 227 crit_enter(); 228 for (i = 0; i < npages; ++i) { 229 vm_page_hold(mbase[i]); 230 xio->xio_pages[i] = mbase[i]; 231 } 232 crit_exit(); 233 lwkt_reltoken(&vm_token); 234 return(0); 235 } 236 237 /* 238 * Cleanup an XIO so it can be destroyed. The pages associated with the 239 * XIO are released. 240 */ 241 void 242 xio_release(xio_t xio) 243 { 244 int i; 245 vm_page_t m; 246 247 lwkt_gettoken(&vm_token); 248 crit_enter(); 249 for (i = 0; i < xio->xio_npages; ++i) { 250 m = xio->xio_pages[i]; 251 if (xio->xio_flags & XIOF_WRITE) 252 vm_page_dirty(m); 253 vm_page_unhold(m); 254 } 255 crit_exit(); 256 lwkt_reltoken(&vm_token); 257 xio->xio_offset = 0; 258 xio->xio_npages = 0; 259 xio->xio_bytes = 0; 260 xio->xio_error = ENOBUFS; 261 } 262 263 /* 264 * Copy data between an XIO and a UIO. If the UIO represents userspace it 265 * must be relative to the current context. 266 * 267 * uoffset is the abstracted starting offset in the XIO, not the actual 268 * offset, and usually starts at 0. 269 * 270 * The XIO is not modified. The UIO is updated to reflect the copy. 271 * 272 * UIO_READ xio -> uio 273 * UIO_WRITE uio -> xio 274 */ 275 int 276 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, size_t *sizep) 277 { 278 size_t bytes; 279 int error; 280 281 bytes = xio->xio_bytes - uoffset; 282 if (bytes > uio->uio_resid) 283 bytes = uio->uio_resid; 284 KKASSERT(bytes >= 0); 285 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset, 286 bytes, uio); 287 if (error == 0) 288 *sizep = bytes; 289 else 290 *sizep = 0; 291 return(error); 292 } 293 294 /* 295 * Copy the specified number of bytes from the xio to a userland 296 * buffer. Return an error code or 0 on success. 297 * 298 * uoffset is the abstracted starting offset in the XIO, not the actual 299 * offset, and usually starts at 0. 300 * 301 * The XIO is not modified. 302 */ 303 int 304 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes) 305 { 306 int i; 307 int n; 308 int error; 309 int offset; 310 vm_page_t m; 311 struct lwbuf *lwb; 312 struct lwbuf lwb_cache; 313 314 if (uoffset + bytes > xio->xio_bytes) 315 return(EFAULT); 316 317 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 318 if ((n = PAGE_SIZE - offset) > bytes) 319 n = bytes; 320 321 error = 0; 322 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 323 i < xio->xio_npages; 324 ++i 325 ) { 326 m = xio->xio_pages[i]; 327 lwb = lwbuf_alloc(m, &lwb_cache); 328 error = copyout((char *)lwbuf_kva(lwb) + offset, uptr, n); 329 lwbuf_free(lwb); 330 if (error) 331 break; 332 bytes -= n; 333 uptr = (char *)uptr + n; 334 if (bytes == 0) 335 break; 336 if ((n = bytes) > PAGE_SIZE) 337 n = PAGE_SIZE; 338 offset = 0; 339 } 340 return(error); 341 } 342 343 /* 344 * Copy the specified number of bytes from the xio to a kernel 345 * buffer. Return an error code or 0 on success. 346 * 347 * uoffset is the abstracted starting offset in the XIO, not the actual 348 * offset, and usually starts at 0. 349 * 350 * The XIO is not modified. 351 */ 352 int 353 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes) 354 { 355 int i; 356 int n; 357 int error; 358 int offset; 359 vm_page_t m; 360 struct lwbuf *lwb; 361 struct lwbuf lwb_cache; 362 363 if (bytes + uoffset > xio->xio_bytes) 364 return(EFAULT); 365 366 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 367 if ((n = PAGE_SIZE - offset) > bytes) 368 n = bytes; 369 370 error = 0; 371 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 372 i < xio->xio_npages; 373 ++i 374 ) { 375 m = xio->xio_pages[i]; 376 lwb = lwbuf_alloc(m, &lwb_cache); 377 bcopy((char *)lwbuf_kva(lwb) + offset, kptr, n); 378 lwbuf_free(lwb); 379 bytes -= n; 380 kptr = (char *)kptr + n; 381 if (bytes == 0) 382 break; 383 if ((n = bytes) > PAGE_SIZE) 384 n = PAGE_SIZE; 385 offset = 0; 386 } 387 return(error); 388 } 389 390 /* 391 * Copy the specified number of bytes from userland to the xio. 392 * Return an error code or 0 on success. 393 * 394 * uoffset is the abstracted starting offset in the XIO, not the actual 395 * offset, and usually starts at 0. 396 * 397 * Data in pages backing the XIO will be modified. 398 */ 399 int 400 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes) 401 { 402 int i; 403 int n; 404 int error; 405 int offset; 406 vm_page_t m; 407 struct lwbuf *lwb; 408 struct lwbuf lwb_cache; 409 410 if (uoffset + bytes > xio->xio_bytes) 411 return(EFAULT); 412 413 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 414 if ((n = PAGE_SIZE - offset) > bytes) 415 n = bytes; 416 417 error = 0; 418 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 419 i < xio->xio_npages; 420 ++i 421 ) { 422 m = xio->xio_pages[i]; 423 lwb = lwbuf_alloc(m, &lwb_cache); 424 error = copyin(uptr, (char *)lwbuf_kva(lwb) + offset, n); 425 lwbuf_free(lwb); 426 if (error) 427 break; 428 bytes -= n; 429 uptr = (const char *)uptr + n; 430 if (bytes == 0) 431 break; 432 if ((n = bytes) > PAGE_SIZE) 433 n = PAGE_SIZE; 434 offset = 0; 435 } 436 return(error); 437 } 438 439 /* 440 * Copy the specified number of bytes from the kernel to the xio. 441 * Return an error code or 0 on success. 442 * 443 * uoffset is the abstracted starting offset in the XIO, not the actual 444 * offset, and usually starts at 0. 445 * 446 * Data in pages backing the XIO will be modified. 447 */ 448 int 449 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes) 450 { 451 int i; 452 int n; 453 int error; 454 int offset; 455 vm_page_t m; 456 struct lwbuf *lwb; 457 struct lwbuf lwb_cache; 458 459 if (uoffset + bytes > xio->xio_bytes) 460 return(EFAULT); 461 462 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 463 if ((n = PAGE_SIZE - offset) > bytes) 464 n = bytes; 465 466 error = 0; 467 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 468 i < xio->xio_npages; 469 ++i 470 ) { 471 m = xio->xio_pages[i]; 472 lwb = lwbuf_alloc(m, &lwb_cache); 473 bcopy(kptr, (char *)lwbuf_kva(lwb) + offset, n); 474 lwbuf_free(lwb); 475 bytes -= n; 476 kptr = (const char *)kptr + n; 477 if (bytes == 0) 478 break; 479 if ((n = bytes) > PAGE_SIZE) 480 n = PAGE_SIZE; 481 offset = 0; 482 } 483 return(error); 484 } 485