/* $NetBSD: uvm_device.c,v 1.48 2006/09/03 21:37:22 christos 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Charles D. Cranor and * Washington University. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * 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_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp */ /* * uvm_device.c: the device pager. */ #include __KERNEL_RCSID(0, "$NetBSD: uvm_device.c,v 1.48 2006/09/03 21:37:22 christos Exp $"); #include "opt_uvmhist.h" #include #include #include #include #include #include #include #include /* * private global data structure * * we keep a list of active device objects in the system. */ LIST_HEAD(udv_list_struct, uvm_device); static struct udv_list_struct udv_list; static struct simplelock udv_lock; /* * functions */ static void udv_init(void); static void udv_reference(struct uvm_object *); static void udv_detach(struct uvm_object *); static int udv_fault(struct uvm_faultinfo *, vaddr_t, struct vm_page **, int, int, vm_prot_t, int); /* * master pager structure */ struct uvm_pagerops uvm_deviceops = { .pgo_init = udv_init, .pgo_reference = udv_reference, .pgo_detach = udv_detach, .pgo_fault = udv_fault, }; /* * the ops! */ /* * udv_init * * init pager private data structures. */ static void udv_init(void) { LIST_INIT(&udv_list); simple_lock_init(&udv_lock); } /* * udv_attach * * get a VM object that is associated with a device. allocate a new * one if needed. * * => caller must _not_ already be holding the lock on the uvm_object. * => in fact, nothing should be locked so that we can sleep here. */ struct uvm_object * udv_attach(void *arg, vm_prot_t accessprot, voff_t off, /* used only for access check */ vsize_t size /* used only for access check */) { dev_t device = *((dev_t *)arg); struct uvm_device *udv, *lcv; const struct cdevsw *cdev; dev_type_mmap((*mapfn)); UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); /* * before we do anything, ensure this device supports mmap */ cdev = cdevsw_lookup(device); if (cdev == NULL) return (NULL); mapfn = cdev->d_mmap; if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) return(NULL); /* * Negative offsets on the object are not allowed. */ if (off < 0) return(NULL); /* * Check that the specified range of the device allows the * desired protection. * * XXX assumes VM_PROT_* == PROT_* * XXX clobbers off and size, but nothing else here needs them. */ while (size != 0) { if ((*mapfn)(device, off, accessprot) == -1) return (NULL); off += PAGE_SIZE; size -= PAGE_SIZE; } /* * keep looping until we get it */ for (;;) { /* * first, attempt to find it on the main list */ simple_lock(&udv_lock); LIST_FOREACH(lcv, &udv_list, u_list) { if (device == lcv->u_device) break; } /* * got it on main list. put a hold on it and unlock udv_lock. */ if (lcv) { /* * if someone else has a hold on it, sleep and start * over again. */ if (lcv->u_flags & UVM_DEVICE_HOLD) { lcv->u_flags |= UVM_DEVICE_WANTED; UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, "udv_attach",0); continue; } /* we are now holding it */ lcv->u_flags |= UVM_DEVICE_HOLD; simple_unlock(&udv_lock); /* * bump reference count, unhold, return. */ simple_lock(&lcv->u_obj.vmobjlock); lcv->u_obj.uo_refs++; simple_unlock(&lcv->u_obj.vmobjlock); simple_lock(&udv_lock); if (lcv->u_flags & UVM_DEVICE_WANTED) wakeup(lcv); lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); simple_unlock(&udv_lock); return(&lcv->u_obj); } /* * did not find it on main list. need to malloc a new one. */ simple_unlock(&udv_lock); /* NOTE: we could sleep in the following malloc() */ MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, M_WAITOK); simple_lock(&udv_lock); /* * now we have to double check to make sure no one added it * to the list while we were sleeping... */ LIST_FOREACH(lcv, &udv_list, u_list) { if (device == lcv->u_device) break; } /* * did we lose a race to someone else? * free our memory and retry. */ if (lcv) { simple_unlock(&udv_lock); FREE(udv, M_TEMP); continue; } /* * we have it! init the data structures, add to list * and return. */ UVM_OBJ_INIT(&udv->u_obj, &uvm_deviceops, 1); udv->u_flags = 0; udv->u_device = device; LIST_INSERT_HEAD(&udv_list, udv, u_list); simple_unlock(&udv_lock); return(&udv->u_obj); } /*NOTREACHED*/ } /* * udv_reference * * add a reference to a VM object. Note that the reference count must * already be one (the passed in reference) so there is no chance of the * udv being released or locked out here. * * => caller must call with object unlocked. */ static void udv_reference(struct uvm_object *uobj) { UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); simple_lock(&uobj->vmobjlock); uobj->uo_refs++; UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", uobj, uobj->uo_refs,0,0); simple_unlock(&uobj->vmobjlock); } /* * udv_detach * * remove a reference to a VM object. * * => caller must call with object unlocked and map locked. */ static void udv_detach(struct uvm_object *uobj) { struct uvm_device *udv = (struct uvm_device *)uobj; UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); /* * loop until done */ again: simple_lock(&uobj->vmobjlock); if (uobj->uo_refs > 1) { uobj->uo_refs--; simple_unlock(&uobj->vmobjlock); UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", uobj,uobj->uo_refs,0,0); return; } /* * is it being held? if so, wait until others are done. */ simple_lock(&udv_lock); if (udv->u_flags & UVM_DEVICE_HOLD) { udv->u_flags |= UVM_DEVICE_WANTED; simple_unlock(&uobj->vmobjlock); UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); goto again; } /* * got it! nuke it now. */ LIST_REMOVE(udv, u_list); if (udv->u_flags & UVM_DEVICE_WANTED) wakeup(udv); simple_unlock(&udv_lock); simple_unlock(&uobj->vmobjlock); FREE(udv, M_TEMP); UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); } /* * udv_fault: non-standard fault routine for device "pages" * * => rather than having a "get" function, we have a fault routine * since we don't return vm_pages we need full control over the * pmap_enter map in * => all the usual fault data structured are locked by the caller * (i.e. maps(read), amap (if any), uobj) * => on return, we unlock all fault data structures * => flags: PGO_ALLPAGES: get all of the pages * PGO_LOCKED: fault data structures are locked * XXX: currently PGO_LOCKED is always required ... consider removing * it as a flag * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] */ static int udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps, int npages, int centeridx, vm_prot_t access_type, int flags) { struct vm_map_entry *entry = ufi->entry; struct uvm_object *uobj = entry->object.uvm_obj; struct uvm_device *udv = (struct uvm_device *)uobj; const struct cdevsw *cdev; vaddr_t curr_va; off_t curr_offset; paddr_t paddr, mdpgno; int lcv, retval; dev_t device; paddr_t (*mapfn)(dev_t, off_t, int); vm_prot_t mapprot; UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); /* * we do not allow device mappings to be mapped copy-on-write * so we kill any attempt to do so here. */ if (UVM_ET_ISCOPYONWRITE(entry)) { UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", entry->etype, 0,0,0); uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); return(EIO); } /* * get device map function. */ device = udv->u_device; cdev = cdevsw_lookup(device); if (cdev == NULL) { uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); return (EIO); } mapfn = cdev->d_mmap; /* * now we must determine the offset in udv to use and the VA to * use for pmap_enter. note that we always use orig_map's pmap * for pmap_enter (even if we have a submap). since virtual * addresses in a submap must match the main map, this is ok. */ /* udv offset = (offset from start of entry) + entry's offset */ curr_offset = entry->offset + (vaddr - entry->start); /* pmap va = vaddr (virtual address of pps[0]) */ curr_va = vaddr; /* * loop over the page range entering in as needed */ retval = 0; for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, curr_va += PAGE_SIZE) { if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) continue; if (pps[lcv] == PGO_DONTCARE) continue; mdpgno = (*mapfn)(device, curr_offset, access_type); if (mdpgno == -1) { retval = EIO; break; } paddr = pmap_phys_address(mdpgno); mapprot = ufi->entry->protection; UVMHIST_LOG(maphist, " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", ufi->orig_map->pmap, curr_va, paddr, mapprot); if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, mapprot, PMAP_CANFAIL | mapprot) != 0) { /* * pmap_enter() didn't have the resource to * enter this mapping. Unlock everything, * wait for the pagedaemon to free up some * pages, and then tell uvm_fault() to start * the fault again. * * XXX Needs some rethinking for the PGO_ALLPAGES * XXX case. */ uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ uvm_wait("udv_fault"); return (ERESTART); } } uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); pmap_update(ufi->orig_map->pmap); return (retval); }