/*- * Copyright (c) 2009 Advanced Computing Technologies LLC * Written by: John H. Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); /* * This pager manages OBJT_SG objects. These objects are backed by * a scatter/gather list of physical address ranges. */ #include #include #include #include #include #include #include #include #include #include #include #include static vm_object_t sg_pager_alloc(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t, struct ucred *); static void sg_pager_dealloc(vm_object_t); static int sg_pager_getpages(vm_object_t, vm_page_t *, int, int); static void sg_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); static boolean_t sg_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); struct pagerops sgpagerops = { .pgo_alloc = sg_pager_alloc, .pgo_dealloc = sg_pager_dealloc, .pgo_getpages = sg_pager_getpages, .pgo_putpages = sg_pager_putpages, .pgo_haspage = sg_pager_haspage, }; static vm_object_t sg_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) { struct sglist *sg; vm_object_t object; vm_pindex_t npages, pindex; int i; /* * Offset should be page aligned. */ if (foff & PAGE_MASK) return (NULL); /* * The scatter/gather list must only include page-aligned * ranges. */ npages = 0; sg = handle; for (i = 0; i < sg->sg_nseg; i++) { if ((sg->sg_segs[i].ss_paddr % PAGE_SIZE) != 0 || (sg->sg_segs[i].ss_len % PAGE_SIZE) != 0) return (NULL); npages += sg->sg_segs[i].ss_len / PAGE_SIZE; } /* * The scatter/gather list has a fixed size. Refuse requests * to map beyond that. */ size = round_page(size); pindex = OFF_TO_IDX(foff + size); if (pindex > npages) return (NULL); /* * Allocate a new object and associate it with the * scatter/gather list. It is ok for our purposes to have * multiple VM objects associated with the same scatter/gather * list because scatter/gather lists are static. This is also * simpler than ensuring a unique object per scatter/gather * list. */ object = vm_object_allocate(OBJT_SG, npages); object->handle = sglist_hold(sg); TAILQ_INIT(&object->un_pager.sgp.sgp_pglist); return (object); } static void sg_pager_dealloc(vm_object_t object) { struct sglist *sg; vm_page_t m; /* * Free up our fake pages. */ while ((m = TAILQ_FIRST(&object->un_pager.sgp.sgp_pglist)) != 0) { TAILQ_REMOVE(&object->un_pager.sgp.sgp_pglist, m, plinks.q); vm_page_putfake(m); } sg = object->handle; sglist_free(sg); } static int sg_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) { struct sglist *sg; vm_page_t m_paddr, page; vm_pindex_t offset; vm_paddr_t paddr; vm_memattr_t memattr; size_t space; int i; VM_OBJECT_ASSERT_WLOCKED(object); sg = object->handle; memattr = object->memattr; VM_OBJECT_WUNLOCK(object); offset = m[reqpage]->pindex; /* * Lookup the physical address of the requested page. An initial * value of '1' instead of '0' is used so we can assert that the * page is found since '0' can be a valid page-aligned physical * address. */ space = 0; paddr = 1; for (i = 0; i < sg->sg_nseg; i++) { if (space + sg->sg_segs[i].ss_len <= (offset * PAGE_SIZE)) { space += sg->sg_segs[i].ss_len; continue; } paddr = sg->sg_segs[i].ss_paddr + offset * PAGE_SIZE - space; break; } KASSERT(paddr != 1, ("invalid SG page index")); /* If "paddr" is a real page, perform a sanity check on "memattr". */ if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL && pmap_page_get_memattr(m_paddr) != memattr) { memattr = pmap_page_get_memattr(m_paddr); printf( "WARNING: A device driver has set \"memattr\" inconsistently.\n"); } /* Return a fake page for the requested page. */ KASSERT(!(m[reqpage]->flags & PG_FICTITIOUS), ("backing page for SG is fake")); /* Construct a new fake page. */ page = vm_page_getfake(paddr, memattr); VM_OBJECT_WLOCK(object); TAILQ_INSERT_TAIL(&object->un_pager.sgp.sgp_pglist, page, plinks.q); /* Free the original pages and insert this fake page into the object. */ for (i = 0; i < count; i++) { if (i == reqpage && vm_page_replace(page, object, offset) != m[i]) panic("sg_pager_getpages: invalid place replacement"); vm_page_lock(m[i]); vm_page_free(m[i]); vm_page_unlock(m[i]); } m[reqpage] = page; page->valid = VM_PAGE_BITS_ALL; return (VM_PAGER_OK); } static void sg_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, int *rtvals) { panic("sg_pager_putpage called"); } static boolean_t sg_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after) { if (before != NULL) *before = 0; if (after != NULL) *after = 0; return (TRUE); }