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; 312 313 if (uoffset + bytes > xio->xio_bytes) 314 return(EFAULT); 315 316 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 317 if ((n = PAGE_SIZE - offset) > bytes) 318 n = bytes; 319 320 error = 0; 321 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 322 i < xio->xio_npages; 323 ++i 324 ) { 325 m = xio->xio_pages[i]; 326 lwb = lwbuf_alloc(m); 327 error = copyout((char *)lwbuf_kva(lwb) + offset, uptr, n); 328 lwbuf_free(lwb); 329 if (error) 330 break; 331 bytes -= n; 332 uptr = (char *)uptr + n; 333 if (bytes == 0) 334 break; 335 if ((n = bytes) > PAGE_SIZE) 336 n = PAGE_SIZE; 337 offset = 0; 338 } 339 return(error); 340 } 341 342 /* 343 * Copy the specified number of bytes from the xio to a kernel 344 * buffer. Return an error code or 0 on success. 345 * 346 * uoffset is the abstracted starting offset in the XIO, not the actual 347 * offset, and usually starts at 0. 348 * 349 * The XIO is not modified. 350 */ 351 int 352 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes) 353 { 354 int i; 355 int n; 356 int error; 357 int offset; 358 vm_page_t m; 359 struct lwbuf *lwb; 360 361 if (bytes + uoffset > xio->xio_bytes) 362 return(EFAULT); 363 364 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 365 if ((n = PAGE_SIZE - offset) > bytes) 366 n = bytes; 367 368 error = 0; 369 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 370 i < xio->xio_npages; 371 ++i 372 ) { 373 m = xio->xio_pages[i]; 374 lwb = lwbuf_alloc(m); 375 bcopy((char *)lwbuf_kva(lwb) + offset, kptr, n); 376 lwbuf_free(lwb); 377 bytes -= n; 378 kptr = (char *)kptr + n; 379 if (bytes == 0) 380 break; 381 if ((n = bytes) > PAGE_SIZE) 382 n = PAGE_SIZE; 383 offset = 0; 384 } 385 return(error); 386 } 387 388 /* 389 * Copy the specified number of bytes from userland to the xio. 390 * Return an error code or 0 on success. 391 * 392 * uoffset is the abstracted starting offset in the XIO, not the actual 393 * offset, and usually starts at 0. 394 * 395 * Data in pages backing the XIO will be modified. 396 */ 397 int 398 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes) 399 { 400 int i; 401 int n; 402 int error; 403 int offset; 404 vm_page_t m; 405 struct lwbuf *lwb; 406 407 if (uoffset + bytes > xio->xio_bytes) 408 return(EFAULT); 409 410 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 411 if ((n = PAGE_SIZE - offset) > bytes) 412 n = bytes; 413 414 error = 0; 415 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 416 i < xio->xio_npages; 417 ++i 418 ) { 419 m = xio->xio_pages[i]; 420 lwb = lwbuf_alloc(m); 421 error = copyin(uptr, (char *)lwbuf_kva(lwb) + offset, n); 422 lwbuf_free(lwb); 423 if (error) 424 break; 425 bytes -= n; 426 uptr = (const char *)uptr + n; 427 if (bytes == 0) 428 break; 429 if ((n = bytes) > PAGE_SIZE) 430 n = PAGE_SIZE; 431 offset = 0; 432 } 433 return(error); 434 } 435 436 /* 437 * Copy the specified number of bytes from the kernel to the xio. 438 * Return an error code or 0 on success. 439 * 440 * uoffset is the abstracted starting offset in the XIO, not the actual 441 * offset, and usually starts at 0. 442 * 443 * Data in pages backing the XIO will be modified. 444 */ 445 int 446 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes) 447 { 448 int i; 449 int n; 450 int error; 451 int offset; 452 vm_page_t m; 453 struct lwbuf *lwb; 454 455 if (uoffset + bytes > xio->xio_bytes) 456 return(EFAULT); 457 458 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 459 if ((n = PAGE_SIZE - offset) > bytes) 460 n = bytes; 461 462 error = 0; 463 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 464 i < xio->xio_npages; 465 ++i 466 ) { 467 m = xio->xio_pages[i]; 468 lwb = lwbuf_alloc(m); 469 bcopy(kptr, (char *)lwbuf_kva(lwb) + offset, n); 470 lwbuf_free(lwb); 471 bytes -= n; 472 kptr = (const char *)kptr + n; 473 if (bytes == 0) 474 break; 475 if ((n = bytes) > PAGE_SIZE) 476 n = PAGE_SIZE; 477 offset = 0; 478 } 479 return(error); 480 } 481