2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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18 * contributors may be used to endorse or promote products derived
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21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_xio.c,v 1.16 2008/05/09 07:24:45 dillon Exp $
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
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.
47 * TODO: check for busy page when modifying, check writeable.
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/malloc.h>
54 #include <sys/vmmeter.h>
55 #include <sys/vnode.h>
58 #include <cpu/lwbuf.h>
61 #include <vm/vm_param.h>
63 #include <vm/vm_kern.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>
74 * Just do basic initialization of an empty XIO
84 xio->xio_pages = xio->xio_internal_pages;
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.
94 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags)
104 addr = trunc_page((vm_offset_t)ubase);
105 xio->xio_flags = flags;
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)
118 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
119 m = vm_fault_page_quick(addr, vmprot, &error);
122 xio->xio_pages[i] = m;
125 if ((n = ubytes) > PAGE_SIZE)
130 * Check linearity, used by syslink to memory map DMA buffers.
132 if (flags & XIOF_VMLINEAR) {
136 if (m->object != m0->object || m->pindex != m0->pindex + i) {
145 * If a failure occured clean out what we loaded and return EFAULT.
146 * Return 0 on success. Do not dirty the pages.
148 if (i < XIO_INTERNAL_PAGES && n) {
149 xio->xio_flags &= ~XIOF_WRITE;
151 xio->xio_error = EFAULT;
154 return(xio->xio_error);
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.
164 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
172 addr = trunc_page((vm_offset_t)kbase);
174 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
176 xio->xio_pages = xio->xio_internal_pages;
178 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
180 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
181 if ((paddr = pmap_kextract(addr)) == 0)
184 m = PHYS_TO_VM_PAGE(paddr);
187 xio->xio_pages[i] = m;
190 if ((n = kbytes) > PAGE_SIZE)
197 * If a failure occured clean out what we loaded and return EFAULT.
198 * Return 0 on success.
200 if (i < XIO_INTERNAL_PAGES && n) {
202 xio->xio_error = EFAULT;
204 return(xio->xio_error);
208 * Initialize an XIO given an array of vm_page pointers. The caller is
209 * responsible for any modified state changes for the pages.
212 xio_init_pages(xio_t xio, struct vm_page **mbase, int npages, int xflags)
216 KKASSERT(npages <= XIO_INTERNAL_PAGES);
218 xio->xio_flags = xflags;
220 xio->xio_bytes = npages * PAGE_SIZE;
221 xio->xio_pages = xio->xio_internal_pages;
222 xio->xio_npages = npages;
225 for (i = 0; i < npages; ++i) {
226 vm_page_hold(mbase[i]);
227 xio->xio_pages[i] = mbase[i];
234 * Cleanup an XIO so it can be destroyed. The pages associated with the
238 xio_release(xio_t xio)
244 for (i = 0; i < xio->xio_npages; ++i) {
245 m = xio->xio_pages[i];
246 if (xio->xio_flags & XIOF_WRITE)
254 xio->xio_error = ENOBUFS;
258 * Copy data between an XIO and a UIO. If the UIO represents userspace it
259 * must be relative to the current context.
261 * uoffset is the abstracted starting offset in the XIO, not the actual
262 * offset, and usually starts at 0.
264 * The XIO is not modified. The UIO is updated to reflect the copy.
266 * UIO_READ xio -> uio
267 * UIO_WRITE uio -> xio
270 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, size_t *sizep)
275 bytes = xio->xio_bytes - uoffset;
276 if (bytes > uio->uio_resid)
277 bytes = uio->uio_resid;
278 KKASSERT(bytes >= 0);
279 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset,
289 * Copy the specified number of bytes from the xio to a userland
290 * buffer. Return an error code or 0 on success.
292 * uoffset is the abstracted starting offset in the XIO, not the actual
293 * offset, and usually starts at 0.
295 * The XIO is not modified.
298 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes)
307 if (uoffset + bytes > xio->xio_bytes)
310 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
311 if ((n = PAGE_SIZE - offset) > bytes)
315 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
319 m = xio->xio_pages[i];
320 lwb = lwbuf_alloc(m);
321 error = copyout((char *)lwbuf_kva(lwb) + offset, uptr, n);
326 uptr = (char *)uptr + n;
329 if ((n = bytes) > PAGE_SIZE)
337 * Copy the specified number of bytes from the xio to a kernel
338 * buffer. Return an error code or 0 on success.
340 * uoffset is the abstracted starting offset in the XIO, not the actual
341 * offset, and usually starts at 0.
343 * The XIO is not modified.
346 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes)
355 if (bytes + uoffset > xio->xio_bytes)
358 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
359 if ((n = PAGE_SIZE - offset) > bytes)
363 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
367 m = xio->xio_pages[i];
368 lwb = lwbuf_alloc(m);
369 bcopy((char *)lwbuf_kva(lwb) + offset, kptr, n);
372 kptr = (char *)kptr + n;
375 if ((n = bytes) > PAGE_SIZE)
383 * Copy the specified number of bytes from userland to the xio.
384 * Return an error code or 0 on success.
386 * uoffset is the abstracted starting offset in the XIO, not the actual
387 * offset, and usually starts at 0.
389 * Data in pages backing the XIO will be modified.
392 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes)
401 if (uoffset + bytes > xio->xio_bytes)
404 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
405 if ((n = PAGE_SIZE - offset) > bytes)
409 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
413 m = xio->xio_pages[i];
414 lwb = lwbuf_alloc(m);
415 error = copyin(uptr, (char *)lwbuf_kva(lwb) + offset, n);
420 uptr = (const char *)uptr + n;
423 if ((n = bytes) > PAGE_SIZE)
431 * Copy the specified number of bytes from the kernel to the xio.
432 * Return an error code or 0 on success.
434 * uoffset is the abstracted starting offset in the XIO, not the actual
435 * offset, and usually starts at 0.
437 * Data in pages backing the XIO will be modified.
440 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes)
449 if (uoffset + bytes > xio->xio_bytes)
452 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
453 if ((n = PAGE_SIZE - offset) > bytes)
457 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
461 m = xio->xio_pages[i];
462 lwb = lwbuf_alloc(m);
463 bcopy(kptr, (char *)lwbuf_kva(lwb) + offset, n);
466 kptr = (const char *)kptr + n;
469 if ((n = bytes) > PAGE_SIZE)