static int uvm_loanuobj(struct uvm_faultinfo *ufi, void ***output, int flags, vaddr_t va) { struct vm_amap *amap = ufi->entry->aref.ar_amap; struct uvm_object *uobj = ufi->entry->object.uvm_obj; struct vm_page *pg; struct vm_anon *anon; int error, npages; bool locked; UVMHIST_FUNC(__func__); UVMHIST_CALLED(loanhist); /* * first we must make sure the page is resident. * * XXXCDC: duplicate code with uvm_fault(). */ mutex_enter(&uobj->vmobjlock); if (uobj->pgops->pgo_get) { /* try locked pgo_get */ npages = 1; pg = NULL; error = (*uobj->pgops->pgo_get)(uobj, va - ufi->entry->start + ufi->entry->offset, &pg, &npages, 0, VM_PROT_READ, MADV_NORMAL, PGO_LOCKED); } else { error = EIO; /* must have pgo_get op */ } /* * check the result of the locked pgo_get. if there is a problem, * then we fail the loan. */ if (error && error != EBUSY) { uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); } /* * if we need to unlock for I/O, do so now. */ if (error == EBUSY) { uvmfault_unlockall(ufi, amap, NULL, NULL); /* locked: uobj */ npages = 1; error = (*uobj->pgops->pgo_get)(uobj, va - ufi->entry->start + ufi->entry->offset, &pg, &npages, 0, VM_PROT_READ, MADV_NORMAL, PGO_SYNCIO); /* locked: <nothing> */ if (error) { if (error == EAGAIN) { tsleep(&lbolt, PVM, "fltagain2", 0); return (0); } return (-1); } /* * pgo_get was a success. attempt to relock everything. */ locked = uvmfault_relock(ufi); if (locked && amap) amap_lock(amap); uobj = pg->uobject; mutex_enter(&uobj->vmobjlock); /* * verify that the page has not be released and re-verify * that amap slot is still free. if there is a problem we * drop our lock (thus force a lookup refresh/retry). */ if ((pg->flags & PG_RELEASED) != 0 || (locked && amap && amap_lookup(&ufi->entry->aref, ufi->orig_rvaddr - ufi->entry->start))) { if (locked) uvmfault_unlockall(ufi, amap, NULL, NULL); locked = false; } /* * didn't get the lock? release the page and retry. */ if (locked == false) { if (pg->flags & PG_WANTED) { wakeup(pg); } if (pg->flags & PG_RELEASED) { mutex_enter(&uvm_pageqlock); uvm_pagefree(pg); mutex_exit(&uvm_pageqlock); mutex_exit(&uobj->vmobjlock); return (0); } mutex_enter(&uvm_pageqlock); uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); pg->flags &= ~(PG_BUSY|PG_WANTED); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); return (0); } } KASSERT(uobj == pg->uobject); /* * at this point we have the page we want ("pg") marked PG_BUSY for us * and we have all data structures locked. do the loanout. page can * not be PG_RELEASED (we caught this above). */ if ((flags & UVM_LOAN_TOANON) == 0) { if (uvm_loanpage(&pg, 1)) { uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); } mutex_exit(&uobj->vmobjlock); **output = pg; (*output)++; return (1); } /* * must be a loan to an anon. check to see if there is already * an anon associated with this page. if so, then just return * a reference to this object. the page should already be * mapped read-only because it is already on loan. */ if (pg->uanon) { anon = pg->uanon; mutex_enter(&anon->an_lock); anon->an_ref++; mutex_exit(&anon->an_lock); if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); **output = anon; (*output)++; return (1); } /* * need to allocate a new anon */ anon = uvm_analloc(); if (anon == NULL) { goto fail; } anon->an_page = pg; pg->uanon = anon; mutex_enter(&uvm_pageqlock); if (pg->wire_count > 0) { mutex_exit(&uvm_pageqlock); UVMHIST_LOG(loanhist, "wired %p", pg,0,0,0); pg->uanon = NULL; anon->an_page = NULL; anon->an_ref--; mutex_exit(&anon->an_lock); uvm_anfree(anon); goto fail; } if (pg->loan_count == 0) { pmap_page_protect(pg, VM_PROT_READ); } pg->loan_count++; uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); mutex_exit(&anon->an_lock); **output = anon; (*output)++; return (1); fail: UVMHIST_LOG(loanhist, "fail", 0,0,0,0); /* * unlock everything and bail out. */ if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); }
static inline int uvm_loanentry(struct uvm_faultinfo *ufi, void ***output, int flags) { vaddr_t curaddr = ufi->orig_rvaddr; vsize_t togo = ufi->size; struct vm_aref *aref = &ufi->entry->aref; struct uvm_object *uobj = ufi->entry->object.uvm_obj; struct vm_anon *anon; int rv, result = 0; UVMHIST_FUNC(__func__); UVMHIST_CALLED(loanhist); /* * lock us the rest of the way down (we unlock before return) */ if (aref->ar_amap) amap_lock(aref->ar_amap); /* * loop until done */ while (togo) { /* * find the page we want. check the anon layer first. */ if (aref->ar_amap) { anon = amap_lookup(aref, curaddr - ufi->entry->start); } else { anon = NULL; } /* locked: map, amap, uobj */ if (anon) { rv = uvm_loananon(ufi, output, flags, anon); } else if (uobj) { rv = uvm_loanuobj(ufi, output, flags, curaddr); } else if (UVM_ET_ISCOPYONWRITE(ufi->entry)) { rv = uvm_loanzero(ufi, output, flags); } else { uvmfault_unlockall(ufi, aref->ar_amap, uobj, NULL); rv = -1; } /* locked: if (rv > 0) => map, amap, uobj [o.w. unlocked] */ KASSERT(rv > 0 || aref->ar_amap == NULL || !mutex_owned(&aref->ar_amap->am_l)); KASSERT(rv > 0 || uobj == NULL || !mutex_owned(&uobj->vmobjlock)); /* total failure */ if (rv < 0) { UVMHIST_LOG(loanhist, "failure %d", rv, 0,0,0); return (-1); } /* relock failed, need to do another lookup */ if (rv == 0) { UVMHIST_LOG(loanhist, "relock failure %d", result ,0,0,0); return (result); } /* * got it... advance to next page */ result++; togo -= PAGE_SIZE; curaddr += PAGE_SIZE; } /* * unlock what we locked, unlock the maps and return */ if (aref->ar_amap) amap_unlock(aref->ar_amap); uvmfault_unlockmaps(ufi, false); UVMHIST_LOG(loanhist, "done %d", result, 0,0,0); return (result); }
/* ARGSUSED */ int sys_mincore(struct lwp *l, const struct sys_mincore_args *uap, register_t *retval) { /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(char *) vec; } */ struct proc *p = l->l_proc; struct vm_page *pg; char *vec, pgi; struct uvm_object *uobj; struct vm_amap *amap; struct vm_anon *anon; struct vm_map_entry *entry; vaddr_t start, end, lim; struct vm_map *map; vsize_t len; int error = 0, npgs; map = &p->p_vmspace->vm_map; start = (vaddr_t)SCARG(uap, addr); len = SCARG(uap, len); vec = SCARG(uap, vec); if (start & PAGE_MASK) return EINVAL; len = round_page(len); end = start + len; if (end <= start) return EINVAL; /* * Lock down vec, so our returned status isn't outdated by * storing the status byte for a page. */ npgs = len >> PAGE_SHIFT; error = uvm_vslock(p->p_vmspace, vec, npgs, VM_PROT_WRITE); if (error) { return error; } vm_map_lock_read(map); if (uvm_map_lookup_entry(map, start, &entry) == false) { error = ENOMEM; goto out; } for (/* nothing */; entry != &map->header && entry->start < end; entry = entry->next) { KASSERT(!UVM_ET_ISSUBMAP(entry)); KASSERT(start >= entry->start); /* Make sure there are no holes. */ if (entry->end < end && (entry->next == &map->header || entry->next->start > entry->end)) { error = ENOMEM; goto out; } lim = end < entry->end ? end : entry->end; /* * Special case for objects with no "real" pages. Those * are always considered resident (mapped devices). */ if (UVM_ET_ISOBJ(entry)) { KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj)); if (UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) { for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) subyte(vec, 1); continue; } } amap = entry->aref.ar_amap; /* upper layer */ uobj = entry->object.uvm_obj; /* lower layer */ if (amap != NULL) amap_lock(amap); if (uobj != NULL) mutex_enter(uobj->vmobjlock); for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) { pgi = 0; if (amap != NULL) { /* Check the upper layer first. */ anon = amap_lookup(&entry->aref, start - entry->start); /* Don't need to lock anon here. */ if (anon != NULL && anon->an_page != NULL) { /* * Anon has the page for this entry * offset. */ pgi = 1; } } if (uobj != NULL && pgi == 0) { /* Check the lower layer. */ pg = uvm_pagelookup(uobj, entry->offset + (start - entry->start)); if (pg != NULL) { /* * Object has the page for this entry * offset. */ pgi = 1; } } (void) subyte(vec, pgi); } if (uobj != NULL) mutex_exit(uobj->vmobjlock); if (amap != NULL) amap_unlock(amap); } out: vm_map_unlock_read(map); uvm_vsunlock(p->p_vmspace, SCARG(uap, vec), npgs); return error; }
int uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap, struct vm_anon *anon) { boolean_t we_own; /* we own anon's page? */ boolean_t locked; /* did we relock? */ struct vm_page *pg; int result; result = 0; /* XXX shut up gcc */ uvmexp.fltanget++; /* bump rusage counters */ if (anon->an_page) curproc->p_ru.ru_minflt++; else curproc->p_ru.ru_majflt++; /* * loop until we get it, or fail. */ while (1) { we_own = FALSE; /* TRUE if we set PG_BUSY on a page */ pg = anon->an_page; /* * if there is a resident page and it is loaned, then anon * may not own it. call out to uvm_anon_lockpage() to ensure * the real owner of the page has been identified and locked. */ if (pg && pg->loan_count) pg = uvm_anon_lockloanpg(anon); /* * page there? make sure it is not busy/released. */ if (pg) { /* * at this point, if the page has a uobject [meaning * we have it on loan], then that uobject is locked * by us! if the page is busy, we drop all the * locks (including uobject) and try again. */ if ((pg->pg_flags & (PG_BUSY|PG_RELEASED)) == 0) { return (VM_PAGER_OK); } atomic_setbits_int(&pg->pg_flags, PG_WANTED); uvmexp.fltpgwait++; /* * the last unlock must be an atomic unlock+wait on * the owner of page */ if (pg->uobject) { /* owner is uobject ? */ uvmfault_unlockall(ufi, amap, NULL, anon); UVM_UNLOCK_AND_WAIT(pg, &pg->uobject->vmobjlock, FALSE, "anonget1",0); } else { /* anon owns page */ uvmfault_unlockall(ufi, amap, NULL, NULL); UVM_UNLOCK_AND_WAIT(pg,&anon->an_lock,0, "anonget2",0); } /* ready to relock and try again */ } else { /* * no page, we must try and bring it in. */ pg = uvm_pagealloc(NULL, 0, anon, 0); if (pg == NULL) { /* out of RAM. */ uvmfault_unlockall(ufi, amap, NULL, anon); uvmexp.fltnoram++; uvm_wait("flt_noram1"); /* ready to relock and try again */ } else { /* we set the PG_BUSY bit */ we_own = TRUE; uvmfault_unlockall(ufi, amap, NULL, anon); /* * we are passing a PG_BUSY+PG_FAKE+PG_CLEAN * page into the uvm_swap_get function with * all data structures unlocked. note that * it is ok to read an_swslot here because * we hold PG_BUSY on the page. */ uvmexp.pageins++; result = uvm_swap_get(pg, anon->an_swslot, PGO_SYNCIO); /* * we clean up after the i/o below in the * "we_own" case */ /* ready to relock and try again */ } } /* * now relock and try again */ locked = uvmfault_relock(ufi); if (locked || we_own) simple_lock(&anon->an_lock); /* * if we own the page (i.e. we set PG_BUSY), then we need * to clean up after the I/O. there are three cases to * consider: * [1] page released during I/O: free anon and ReFault. * [2] I/O not OK. free the page and cause the fault * to fail. * [3] I/O OK! activate the page and sync with the * non-we_own case (i.e. drop anon lock if not locked). */ if (we_own) { if (pg->pg_flags & PG_WANTED) { /* still holding object lock */ wakeup(pg); } /* un-busy! */ atomic_clearbits_int(&pg->pg_flags, PG_WANTED|PG_BUSY|PG_FAKE); UVM_PAGE_OWN(pg, NULL); /* * if we were RELEASED during I/O, then our anon is * no longer part of an amap. we need to free the * anon and try again. */ if (pg->pg_flags & PG_RELEASED) { pmap_page_protect(pg, VM_PROT_NONE); simple_unlock(&anon->an_lock); uvm_anfree(anon); /* frees page for us */ if (locked) uvmfault_unlockall(ufi, amap, NULL, NULL); uvmexp.fltpgrele++; return (VM_PAGER_REFAULT); /* refault! */ } if (result != VM_PAGER_OK) { KASSERT(result != VM_PAGER_PEND); /* remove page from anon */ anon->an_page = NULL; /* * remove the swap slot from the anon * and mark the anon as having no real slot. * don't free the swap slot, thus preventing * it from being used again. */ uvm_swap_markbad(anon->an_swslot, 1); anon->an_swslot = SWSLOT_BAD; /* * note: page was never !PG_BUSY, so it * can't be mapped and thus no need to * pmap_page_protect it... */ uvm_lock_pageq(); uvm_pagefree(pg); uvm_unlock_pageq(); if (locked) uvmfault_unlockall(ufi, amap, NULL, anon); else simple_unlock(&anon->an_lock); return (VM_PAGER_ERROR); } /* * must be OK, clear modify (already PG_CLEAN) * and activate */ pmap_clear_modify(pg); uvm_lock_pageq(); uvm_pageactivate(pg); uvm_unlock_pageq(); if (!locked) simple_unlock(&anon->an_lock); } /* * we were not able to relock. restart fault. */ if (!locked) return (VM_PAGER_REFAULT); /* * verify no one has touched the amap and moved the anon on us. */ if (ufi != NULL && amap_lookup(&ufi->entry->aref, ufi->orig_rvaddr - ufi->entry->start) != anon) { uvmfault_unlockall(ufi, amap, NULL, anon); return (VM_PAGER_REFAULT); } /* * try it again! */ uvmexp.fltanretry++; continue; } /* while (1) */ /*NOTREACHED*/ }
/* ARGSUSED */ int sys_mincore(struct proc *p, void *v, register_t *retval) { struct sys_mincore_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(char *) vec; } */ *uap = v; vm_page_t m; char *vec, pgi; struct uvm_object *uobj; struct vm_amap *amap; struct vm_anon *anon; vm_map_entry_t entry; vaddr_t start, end, lim; vm_map_t map; vsize_t len, npgs; int error = 0; map = &p->p_vmspace->vm_map; start = (vaddr_t)SCARG(uap, addr); len = SCARG(uap, len); vec = SCARG(uap, vec); if (start & PAGE_MASK) return (EINVAL); len = round_page(len); end = start + len; if (end <= start) return (EINVAL); npgs = len >> PAGE_SHIFT; /* * Lock down vec, so our returned status isn't outdated by * storing the status byte for a page. */ if ((error = uvm_vslock(p, vec, npgs, VM_PROT_WRITE)) != 0) return (error); vm_map_lock_read(map); if (uvm_map_lookup_entry(map, start, &entry) == FALSE) { error = ENOMEM; goto out; } for (/* nothing */; entry != &map->header && entry->start < end; entry = entry->next) { KASSERT(!UVM_ET_ISSUBMAP(entry)); KASSERT(start >= entry->start); /* Make sure there are no holes. */ if (entry->end < end && (entry->next == &map->header || entry->next->start > entry->end)) { error = ENOMEM; goto out; } lim = end < entry->end ? end : entry->end; /* * Special case for objects with no "real" pages. Those * are always considered resident (mapped devices). */ if (UVM_ET_ISOBJ(entry)) { KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj)); if (entry->object.uvm_obj->pgops->pgo_releasepg == NULL) { pgi = 1; for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) copyout(&pgi, vec, sizeof(char)); continue; } } amap = entry->aref.ar_amap; /* top layer */ uobj = entry->object.uvm_obj; /* bottom layer */ if (uobj != NULL) simple_lock(&uobj->vmobjlock); for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) { pgi = 0; if (amap != NULL) { /* Check the top layer first. */ anon = amap_lookup(&entry->aref, start - entry->start); /* Don't need to lock anon here. */ if (anon != NULL && anon->an_page != NULL) { /* * Anon has the page for this entry * offset. */ pgi = 1; } } if (uobj != NULL && pgi == 0) { /* Check the bottom layer. */ m = uvm_pagelookup(uobj, entry->offset + (start - entry->start)); if (m != NULL) { /* * Object has the page for this entry * offset. */ pgi = 1; } } copyout(&pgi, vec, sizeof(char)); } if (uobj != NULL) simple_unlock(&uobj->vmobjlock); } out: vm_map_unlock_read(map); uvm_vsunlock(p, SCARG(uap, vec), npgs); return (error); }