uvm_km.c

基于组件方式开发操作系统的OSKIT源代码

		}

		UVMHIST_LOG(maphist,"  page 0x%x, busy=%d", pp,
		    pp->flags & PG_BUSY, 0, 0);
		KASSERT((pp->flags & PG_BUSY) == 0);
		KASSERT((pp->pqflags & PQ_ACTIVE) == 0);
		KASSERT((pp->pqflags & PQ_INACTIVE) == 0);
		uvm_pagefree(pp);
	}
	simple_unlock(&uobj->vmobjlock);
}


/*
 * uvm_km_kmemalloc: lower level kernel memory allocator for malloc()
 *
 * => we map wired memory into the specified map using the obj passed in
 * => NOTE: we can return NULL even if we can wait if there is not enough
 *	free VM space in the map... caller should be prepared to handle
 *	this case.
 * => we return KVA of memory allocated
 * => flags: NOWAIT, VALLOC - just allocate VA, TRYLOCK - fail if we can't
 *	lock the map
 */

vaddr_t
uvm_km_kmemalloc(map, obj, size, flags)
	vm_map_t map;
	struct uvm_object *obj;
	vsize_t size;
	int flags;
{
	vaddr_t kva, loopva;
	vaddr_t offset;
	struct vm_page *pg;
	UVMHIST_FUNC("uvm_km_kmemalloc"); UVMHIST_CALLED(maphist);

	UVMHIST_LOG(maphist,"  (map=0x%x, obj=0x%x, size=0x%x, flags=%d)",
		    map, obj, size, flags);
	KASSERT(vm_map_pmap(map) == pmap_kernel());

	/*
	 * setup for call
	 */

	size = round_page(size);
	kva = vm_map_min(map);	/* hint */

	/*
	 * allocate some virtual space
	 */

	if (__predict_false(uvm_map(map, &kva, size, obj, UVM_UNKNOWN_OFFSET,
	      0, UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
			  UVM_ADV_RANDOM, (flags & UVM_KMF_TRYLOCK))) 
			!= KERN_SUCCESS)) {
		UVMHIST_LOG(maphist, "<- done (no VM)",0,0,0,0);
		return(0);
	}

	/*
	 * if all we wanted was VA, return now
	 */

	if (flags & UVM_KMF_VALLOC) {
		UVMHIST_LOG(maphist,"<- done valloc (kva=0x%x)", kva,0,0,0);
		return(kva);
	}

	/*
	 * recover object offset from virtual address
	 */

	offset = kva - vm_map_min(kernel_map);
	UVMHIST_LOG(maphist, "  kva=0x%x, offset=0x%x", kva, offset,0,0);

	/*
	 * now allocate and map in the memory... note that we are the only ones
	 * whom should ever get a handle on this area of VM.
	 */

	loopva = kva;
	while (size) {
		simple_lock(&obj->vmobjlock);
		pg = uvm_pagealloc(obj, offset, NULL, 0);
		if (pg) {
			pg->flags &= ~PG_BUSY;	/* new page */
			UVM_PAGE_OWN(pg, NULL);
		}
		simple_unlock(&obj->vmobjlock);
		
		/*
		 * out of memory?
		 */

		if (__predict_false(pg == NULL)) {
			if (flags & UVM_KMF_NOWAIT) {
				/* free everything! */
				uvm_unmap(map, kva, kva + size);
				return(0);
			} else {
				uvm_wait("km_getwait2");	/* sleep here */
				continue;
			}
		}
		
		/*
		 * map it in: note that we call pmap_enter with the map and
		 * object unlocked in case we are kmem_map/kmem_object
		 * (because if pmap_enter wants to allocate out of kmem_object
		 * it will need to lock it itself!)
		 */

		if (UVM_OBJ_IS_INTRSAFE_OBJECT(obj)) {
			pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg),
			    VM_PROT_ALL);
		} else {
			pmap_enter(map->pmap, loopva, VM_PAGE_TO_PHYS(pg),
			    UVM_PROT_ALL,
			    PMAP_WIRED | VM_PROT_READ | VM_PROT_WRITE);
		}
		loopva += PAGE_SIZE;
		offset += PAGE_SIZE;
		size -= PAGE_SIZE;
	}
	UVMHIST_LOG(maphist,"<- done (kva=0x%x)", kva,0,0,0);
	return(kva);
}

/*
 * uvm_km_free: free an area of kernel memory
 */

void
uvm_km_free(map, addr, size)
	vm_map_t map;
	vaddr_t addr;
	vsize_t size;
{
	uvm_unmap(map, trunc_page(addr), round_page(addr+size));
}

/*
 * uvm_km_free_wakeup: free an area of kernel memory and wake up
 * anyone waiting for vm space.
 *
 * => XXX: "wanted" bit + unlock&wait on other end?
 */

void
uvm_km_free_wakeup(map, addr, size)
	vm_map_t map;
	vaddr_t addr;
	vsize_t size;
{
	vm_map_entry_t dead_entries;

	vm_map_lock(map);
	(void)uvm_unmap_remove(map, trunc_page(addr), round_page(addr+size), 
			 &dead_entries);
	wakeup(map);
	vm_map_unlock(map);

	if (dead_entries != NULL)
		uvm_unmap_detach(dead_entries, 0);
}

/*
 * uvm_km_alloc1: allocate wired down memory in the kernel map.
 *
 * => we can sleep if needed
 */

vaddr_t
uvm_km_alloc1(map, size, zeroit)
	vm_map_t map;
	vsize_t size;
	boolean_t zeroit;
{
	vaddr_t kva, loopva, offset;
	struct vm_page *pg;
	UVMHIST_FUNC("uvm_km_alloc1"); UVMHIST_CALLED(maphist);

	UVMHIST_LOG(maphist,"(map=0x%x, size=0x%x)", map, size,0,0);
	KASSERT(vm_map_pmap(map) == pmap_kernel());

	size = round_page(size);
	kva = vm_map_min(map);		/* hint */

	/*
	 * allocate some virtual space
	 */

	if (__predict_false(uvm_map(map, &kva, size, uvm.kernel_object,
	      UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL,
					      UVM_INH_NONE, UVM_ADV_RANDOM,
					      0)) != KERN_SUCCESS)) {
		UVMHIST_LOG(maphist,"<- done (no VM)",0,0,0,0);
		return(0);
	}

	/*
	 * recover object offset from virtual address
	 */

	offset = kva - vm_map_min(kernel_map);
	UVMHIST_LOG(maphist,"  kva=0x%x, offset=0x%x", kva, offset,0,0);

	/*
	 * now allocate the memory.  we must be careful about released pages.
	 */

	loopva = kva;
	while (size) {
		simple_lock(&uvm.kernel_object->vmobjlock);
		pg = uvm_pagelookup(uvm.kernel_object, offset);

		/*
		 * if we found a page in an unallocated region, it must be
		 * released
		 */
		if (pg) {
			if ((pg->flags & PG_RELEASED) == 0)
				panic("uvm_km_alloc1: non-released page");
			pg->flags |= PG_WANTED;
			UVM_UNLOCK_AND_WAIT(pg, &uvm.kernel_object->vmobjlock,
			    FALSE, "km_alloc", 0);
			continue;   /* retry */
		}
		
		/* allocate ram */
		pg = uvm_pagealloc(uvm.kernel_object, offset, NULL, 0);
		if (pg) {
			pg->flags &= ~PG_BUSY;	/* new page */
			UVM_PAGE_OWN(pg, NULL);
		}
		simple_unlock(&uvm.kernel_object->vmobjlock);
		if (__predict_false(pg == NULL)) {
			uvm_wait("km_alloc1w");	/* wait for memory */
			continue;
		}
		
		/*
		 * map it in; note we're never called with an intrsafe
		 * object, so we always use regular old pmap_enter().
		 */
		pmap_enter(map->pmap, loopva, VM_PAGE_TO_PHYS(pg),
		    UVM_PROT_ALL, PMAP_WIRED | VM_PROT_READ | VM_PROT_WRITE);

		loopva += PAGE_SIZE;
		offset += PAGE_SIZE;
		size -= PAGE_SIZE;
	}
	
	/*
	 * zero on request (note that "size" is now zero due to the above loop
	 * so we need to subtract kva from loopva to reconstruct the size).
	 */

	if (zeroit)
		memset((caddr_t)kva, 0, loopva - kva);

	UVMHIST_LOG(maphist,"<- done (kva=0x%x)", kva,0,0,0);
	return(kva);
}

/*
 * uvm_km_valloc: allocate zero-fill memory in the kernel's address space
 *
 * => memory is not allocated until fault time
 */

vaddr_t
uvm_km_valloc(map, size)
	vm_map_t map;
	vsize_t size;
{
	return(uvm_km_valloc_align(map, size, 0));
}

vaddr_t
uvm_km_valloc_align(map, size, align)
	vm_map_t map;
	vsize_t size;
	vsize_t align;
{
	vaddr_t kva;
	UVMHIST_FUNC("uvm_km_valloc"); UVMHIST_CALLED(maphist);

	UVMHIST_LOG(maphist, "(map=0x%x, size=0x%x)", map, size, 0,0);
	KASSERT(vm_map_pmap(map) == pmap_kernel());

	size = round_page(size);
	kva = vm_map_min(map);		/* hint */

	/*
	 * allocate some virtual space.  will be demand filled by kernel_object.
	 */

	if (__predict_false(uvm_map(map, &kva, size, uvm.kernel_object,
	    UVM_UNKNOWN_OFFSET, align, UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL,
					    UVM_INH_NONE, UVM_ADV_RANDOM,
					    0)) != KERN_SUCCESS)) {
		UVMHIST_LOG(maphist, "<- done (no VM)", 0,0,0,0);
		return(0);
	}

	UVMHIST_LOG(maphist, "<- done (kva=0x%x)", kva,0,0,0);
	return(kva);
}

/*
 * uvm_km_valloc_wait: allocate zero-fill memory in the kernel's address space
 *
 * => memory is not allocated until fault time
 * => if no room in map, wait for space to free, unless requested size
 *    is larger than map (in which case we return 0)
 */

vaddr_t
uvm_km_valloc_prefer_wait(map, size, prefer)
	vm_map_t map;
	vsize_t size;
	voff_t prefer;
{
	vaddr_t kva;
	UVMHIST_FUNC("uvm_km_valloc_prefer_wait"); UVMHIST_CALLED(maphist);

	UVMHIST_LOG(maphist, "(map=0x%x, size=0x%x)", map, size, 0,0);
	KASSERT(vm_map_pmap(map) == pmap_kernel());

	size = round_page(size);
	if (size > vm_map_max(map) - vm_map_min(map))
		return(0);

	while (1) {
		kva = vm_map_min(map);		/* hint */

		/*
		 * allocate some virtual space.   will be demand filled
		 * by kernel_object.
		 */

		if (__predict_true(uvm_map(map, &kva, size, uvm.kernel_object,
		    prefer, 0, UVM_MAPFLAG(UVM_PROT_ALL,
		    UVM_PROT_ALL, UVM_INH_NONE, UVM_ADV_RANDOM, 0))
		    == KERN_SUCCESS)) {
			UVMHIST_LOG(maphist,"<- done (kva=0x%x)", kva,0,0,0);
			return(kva);
		}

		/*
		 * failed.  sleep for a while (on map)
		 */

		UVMHIST_LOG(maphist,"<<<sleeping>>>",0,0,0,0);
		tsleep((caddr_t)map, PVM, "vallocwait", 0);
	}
	/*NOTREACHED*/
}

vaddr_t
uvm_km_valloc_wait(map, size)
	vm_map_t map;
	vsize_t size;
{
	return uvm_km_valloc_prefer_wait(map, size, UVM_UNKNOWN_OFFSET);
}

/* Sanity; must specify both or none. */
#if (defined(PMAP_MAP_POOLPAGE) || defined(PMAP_UNMAP_POOLPAGE)) && \
    (!defined(PMAP_MAP_POOLPAGE) || !defined(PMAP_UNMAP_POOLPAGE))
#error Must specify MAP and UNMAP together.
#endif

/*
 * uvm_km_alloc_poolpage: allocate a page for the pool allocator
 *
 * => if the pmap specifies an alternate mapping method, we use it.
 */

/* ARGSUSED */
vaddr_t
uvm_km_alloc_poolpage1(map, obj, waitok)
	vm_map_t map;
	struct uvm_object *obj;
	boolean_t waitok;
{
#if defined(PMAP_MAP_POOLPAGE)
	struct vm_page *pg;
	vaddr_t va;

 again:
	pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_USERESERVE);
	if (__predict_false(pg == NULL)) {
		if (waitok) {
			uvm_wait("plpg");
			goto again;
		} else
			return (0);
	}
	va = PMAP_MAP_POOLPAGE(VM_PAGE_TO_PHYS(pg));
	if (__predict_false(va == 0))
		uvm_pagefree(pg);
	return (va);
#else
	vaddr_t va;
	int s;

	/*
	 * NOTE: We may be called with a map that doens't require splimp
	 * protection (e.g. kernel_map).  However, it does not hurt to
	 * go to splimp in this case (since unprocted maps will never be
	 * accessed in interrupt context).
	 *
	 * XXX We may want to consider changing the interface to this
	 * XXX function.
	 */

	s = splimp();
	va = uvm_km_kmemalloc(map, obj, PAGE_SIZE, waitok ? 0 : UVM_KMF_NOWAIT);
	splx(s);
	return (va);
#endif /* PMAP_MAP_POOLPAGE */
}

/*
 * uvm_km_free_poolpage: free a previously allocated pool page
 *
 * => if the pmap specifies an alternate unmapping method, we use it.
 */

/* ARGSUSED */
void
uvm_km_free_poolpage1(map, addr)
	vm_map_t map;
	vaddr_t addr;
{
#if defined(PMAP_UNMAP_POOLPAGE)
	paddr_t pa;

	pa = PMAP_UNMAP_POOLPAGE(addr);
	uvm_pagefree(PHYS_TO_VM_PAGE(pa));
#else
	int s;

	/*
	 * NOTE: We may be called with a map that doens't require splimp
	 * protection (e.g. kernel_map).  However, it does not hurt to
	 * go to splimp in this case (since unprocted maps will never be
	 * accessed in interrupt context).
	 *
	 * XXX We may want to consider changing the interface to this
	 * XXX function.
	 */

	s = splimp();
	uvm_km_free(map, addr, PAGE_SIZE);
	splx(s);
#endif /* PMAP_UNMAP_POOLPAGE */
}