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 1.9 2005/03/02 18:42:08 hmp 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 #include <sys/sfbuf.h> 58 59 #include <vm/vm.h> 60 #include <vm/vm_param.h> 61 #include <sys/lock.h> 62 #include <vm/vm_kern.h> 63 #include <vm/pmap.h> 64 #include <vm/vm_map.h> 65 #include <vm/vm_object.h> 66 #include <vm/vm_page.h> 67 #include <vm/vm_pageout.h> 68 #include <vm/vm_pager.h> 69 #include <vm/vm_extern.h> 70 #include <vm/vm_page2.h> 71 72 /* 73 * Just do basic initialization of an empty XIO 74 */ 75 void 76 xio_init(xio_t xio) 77 { 78 xio->xio_flags = 0; 79 xio->xio_bytes = 0; 80 xio->xio_error = 0; 81 xio->xio_offset = 0; 82 xio->xio_npages = 0; 83 xio->xio_pages = xio->xio_internal_pages; 84 } 85 86 /* 87 * Initialize an XIO given a userspace buffer. 0 is returned on success, 88 * an error code on failure. The actual number of bytes that could be 89 * accomodated in the XIO will be stored in xio_bytes and the page offset 90 * will be stored in xio_offset. 91 */ 92 int 93 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags) 94 { 95 vm_offset_t addr; 96 vm_paddr_t paddr; 97 vm_page_t m; 98 int i; 99 int n; 100 int s; 101 int vmprot; 102 103 addr = trunc_page((vm_offset_t)ubase); 104 xio->xio_flags = flags; 105 xio->xio_bytes = 0; 106 xio->xio_error = 0; 107 if (ubytes == 0) { 108 xio->xio_offset = 0; 109 xio->xio_npages = 0; 110 } else { 111 vmprot = (flags & XIOF_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 112 xio->xio_offset = (vm_offset_t)ubase & PAGE_MASK; 113 xio->xio_pages = xio->xio_internal_pages; 114 if ((n = PAGE_SIZE - xio->xio_offset) > ubytes) 115 n = ubytes; 116 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) { 117 if (vm_fault_quick((caddr_t)addr, vmprot) < 0) 118 break; 119 if ((paddr = pmap_kextract(addr)) == 0) 120 break; 121 s = splvm(); 122 m = PHYS_TO_VM_PAGE(paddr); 123 vm_page_hold(m); 124 splx(s); 125 xio->xio_pages[i] = m; 126 ubytes -= n; 127 xio->xio_bytes += n; 128 if ((n = ubytes) > PAGE_SIZE) 129 n = PAGE_SIZE; 130 addr += PAGE_SIZE; 131 } 132 xio->xio_npages = i; 133 134 /* 135 * If a failure occured clean out what we loaded and return EFAULT. 136 * Return 0 on success. 137 */ 138 if (i < XIO_INTERNAL_PAGES && n) { 139 xio_release(xio); 140 xio->xio_error = EFAULT; 141 } 142 } 143 return(xio->xio_error); 144 } 145 146 /* 147 * Initialize an XIO given a kernelspace buffer. 0 is returned on success, 148 * an error code on failure. The actual number of bytes that could be 149 * accomodated in the XIO will be stored in xio_bytes and the page offset 150 * will be stored in xio_offset. 151 */ 152 int 153 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes) 154 { 155 vm_offset_t addr; 156 vm_paddr_t paddr; 157 vm_page_t m; 158 int i; 159 int n; 160 int s; 161 162 addr = trunc_page((vm_offset_t)kbase); 163 xio->xio_flags = 0; 164 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK; 165 xio->xio_bytes = 0; 166 xio->xio_pages = xio->xio_internal_pages; 167 xio->xio_error = 0; 168 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes) 169 n = kbytes; 170 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) { 171 if ((paddr = pmap_kextract(addr)) == 0) 172 break; 173 s = splvm(); 174 m = PHYS_TO_VM_PAGE(paddr); 175 vm_page_hold(m); 176 splx(s); 177 xio->xio_pages[i] = m; 178 kbytes -= n; 179 xio->xio_bytes += n; 180 if ((n = kbytes) > PAGE_SIZE) 181 n = PAGE_SIZE; 182 addr += PAGE_SIZE; 183 } 184 xio->xio_npages = i; 185 186 /* 187 * If a failure occured clean out what we loaded and return EFAULT. 188 * Return 0 on success. 189 */ 190 if (i < XIO_INTERNAL_PAGES && n) { 191 xio_release(xio); 192 xio->xio_error = EFAULT; 193 } 194 return(xio->xio_error); 195 } 196 197 /* 198 * Cleanup an XIO so it can be destroyed. The pages associated with the 199 * XIO are released. 200 */ 201 void 202 xio_release(xio_t xio) 203 { 204 int i; 205 int s; 206 vm_page_t m; 207 208 s = splvm(); 209 for (i = 0; i < xio->xio_npages; ++i) { 210 m = xio->xio_pages[i]; 211 vm_page_unhold(m); 212 } 213 splx(s); 214 xio->xio_offset = 0; 215 xio->xio_npages = 0; 216 xio->xio_bytes = 0; 217 xio->xio_error = ENOBUFS; 218 } 219 220 /* 221 * Copy data between an XIO and a UIO. If the UIO represents userspace it 222 * must be relative to the current context. 223 * 224 * uoffset is the abstracted starting offset in the XIO, not the actual 225 * offset, and usually starts at 0. 226 * 227 * The XIO is not modified. The UIO is updated to reflect the copy. 228 * 229 * UIO_READ xio -> uio 230 * UIO_WRITE uio -> xio 231 */ 232 int 233 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep) 234 { 235 int error; 236 int bytes; 237 238 bytes = xio->xio_bytes - uoffset; 239 if (bytes > uio->uio_resid) 240 bytes = uio->uio_resid; 241 KKASSERT(bytes >= 0); 242 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset, 243 bytes, uio); 244 if (error == 0) 245 *sizep = bytes; 246 else 247 *sizep = 0; 248 return(error); 249 } 250 251 /* 252 * Copy the specified number of bytes from the xio to a userland 253 * buffer. Return an error code or 0 on success. 254 * 255 * uoffset is the abstracted starting offset in the XIO, not the actual 256 * offset, and usually starts at 0. 257 * 258 * The XIO is not modified. 259 */ 260 int 261 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes) 262 { 263 int i; 264 int n; 265 int error; 266 int offset; 267 vm_page_t m; 268 struct sf_buf *sf; 269 270 if (bytes > xio->xio_bytes) 271 return(EFAULT); 272 273 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 274 if ((n = PAGE_SIZE - offset) > bytes) 275 n = bytes; 276 277 error = 0; 278 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 279 i < xio->xio_npages; 280 ++i 281 ) { 282 m = xio->xio_pages[i]; 283 sf = sf_buf_alloc(m, SFB_CPUPRIVATE); 284 error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n); 285 sf_buf_free(sf); 286 if (error) 287 break; 288 bytes -= n; 289 uptr = (char *)uptr + n; 290 if (bytes == 0) 291 break; 292 if ((n = bytes) > PAGE_SIZE) 293 n = PAGE_SIZE; 294 offset = 0; 295 } 296 return(error); 297 } 298 299 /* 300 * Copy the specified number of bytes from the xio to a kernel 301 * buffer. Return an error code or 0 on success. 302 * 303 * uoffset is the abstracted starting offset in the XIO, not the actual 304 * offset, and usually starts at 0. 305 * 306 * The XIO is not modified. 307 */ 308 int 309 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes) 310 { 311 int i; 312 int n; 313 int error; 314 int offset; 315 vm_page_t m; 316 struct sf_buf *sf; 317 318 if (bytes + uoffset > xio->xio_bytes) 319 return(EFAULT); 320 321 offset = (xio->xio_offset + uoffset) & PAGE_MASK; 322 if ((n = PAGE_SIZE - offset) > bytes) 323 n = bytes; 324 325 error = 0; 326 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT; 327 i < xio->xio_npages; 328 ++i 329 ) { 330 m = xio->xio_pages[i]; 331 sf = sf_buf_alloc(m, SFB_CPUPRIVATE); 332 bcopy((char *)sf_buf_kva(sf) + offset, kptr, n); 333 sf_buf_free(sf); 334 bytes -= n; 335 kptr = (char *)kptr + n; 336 if (bytes == 0) 337 break; 338 if ((n = bytes) > PAGE_SIZE) 339 n = PAGE_SIZE; 340 offset = 0; 341 } 342 return(error); 343 } 344 345