/* $NetBSD: uvm_io.c,v 1.30 2024/05/03 07:09:20 skrll Exp $ */ /* * Copyright (c) 1997 Charles D. Cranor and Washington University. * 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 ``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 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. * * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp */ /* * uvm_io.c: uvm i/o ops */ #include __KERNEL_RCSID(0, "$NetBSD: uvm_io.c,v 1.30 2024/05/03 07:09:20 skrll Exp $"); #include #include #include #include #include /* * functions */ /* * uvm_io: perform I/O on a map * * => caller must have a reference to "map" so that it doesn't go away * while we are working. */ int uvm_io(struct vm_map *map, struct uio *uio, int flags) { vaddr_t baseva, endva, pageoffset, kva; vsize_t chunksz, togo, sz; struct vm_map_entry *dead_entries; int error; /* * step 0: sanity checks and set up for copy loop. start with a * large chunk size. if we have trouble finding vm space we will * reduce it. */ if (uio->uio_resid == 0) return 0; togo = uio->uio_resid; baseva = (vaddr_t) uio->uio_offset; endva = baseva + (togo - 1); if (endva < baseva) /* wrap around? */ return EIO; if (baseva >= VM_MAXUSER_ADDRESS) return 0; if (endva >= VM_MAXUSER_ADDRESS) /* EOF truncate */ togo = togo - (endva - VM_MAXUSER_ADDRESS + 1); pageoffset = baseva & PAGE_MASK; baseva = trunc_page(baseva); chunksz = MIN(round_page(togo + pageoffset), trunc_page(MAXPHYS)); error = 0; flags |= UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | UVM_EXTRACT_FIXPROT; /* XXX cannot use QREF with without AMAP_REFALL, and REFALL is unsafe */ flags &= ~UVM_EXTRACT_QREF; /* * step 1: main loop... while we've got data to move */ for (/*null*/; togo > 0 ; pageoffset = 0) { /* * step 2: extract mappings from the map into kernel_map */ error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, flags); if (error) { /* retry with a smaller chunk... */ if (error == ENOMEM && chunksz > PAGE_SIZE) { chunksz = trunc_page(chunksz / 2); if (chunksz < PAGE_SIZE) chunksz = PAGE_SIZE; continue; } break; } /* * step 3: move a chunk of data */ sz = chunksz - pageoffset; if (sz > togo) sz = togo; error = uiomove((void *) (kva + pageoffset), sz, uio); togo -= sz; baseva += chunksz; /* * step 4: unmap the area of kernel memory */ vm_map_lock(kernel_map); uvm_unmap_remove(kernel_map, kva, kva + chunksz, &dead_entries, 0); vm_map_unlock(kernel_map); if (dead_entries != NULL) uvm_unmap_detach(dead_entries, AMAP_REFALL); if (error) break; } return error; }