+ }
+}
+
+static boolean_t
+ztPresent(const void * address, size_t size)
+{
+ vm_map_offset_t addr = (vm_map_offset_t) address;
+ vm_map_offset_t page, end;
+ boolean_t result;
+
+ page = trunc_page(addr);
+ end = round_page(addr + size);
+ for (result = TRUE; (page < end); page += page_size) {
+ result = pmap_find_phys(kernel_pmap, page);
+ if (!result) {
+ break;
+ }
+ }
+ return result;
+}
+
+
+void __unused
+ztDump(boolean_t sanity);
+void __unused
+ztDump(boolean_t sanity)
+{
+ uint32_t q, cq, p;
+
+ for (q = 0; q <= ztFreeIndexMax; q++) {
+ p = q;
+ do{
+ if (sanity) {
+ cq = ztLog2down(ztBlocks[p].size);
+ if (cq > ztFreeIndexMax) {
+ cq = ztFreeIndexMax;
+ }
+ if (!ztBlocks[p].free
+ || ((p != q) && (q != cq))
+ || (ztBlocks[ztBlocks[p].next].prev != p)
+ || (ztBlocks[ztBlocks[p].prev].next != p)) {
+ kprintf("zterror at %d", p);
+ ztDump(FALSE);
+ kprintf("zterror at %d", p);
+ assert(FALSE);
+ }
+ continue;
+ }
+ kprintf("zt[%03d]%c %d, %d, %d\n",
+ p, ztBlocks[p].free ? 'F' : 'A',
+ ztBlocks[p].next, ztBlocks[p].prev,
+ ztBlocks[p].size);
+ p = ztBlocks[p].next;
+ if (p == q) {
+ break;
+ }
+ }while (p != q);
+ if (!sanity) {
+ printf("\n");
+ }
+ }
+ if (!sanity) {
+ printf("-----------------------\n");
+ }
+}
+
+
+
+#define ZTBDEQ(idx) \
+ ztBlocks[ztBlocks[(idx)].prev].next = ztBlocks[(idx)].next; \
+ ztBlocks[ztBlocks[(idx)].next].prev = ztBlocks[(idx)].prev;
+
+static void
+ztFree(zone_t zone __unused, uint32_t index, uint32_t count)
+{
+ uint32_t q, w, p, size, merge;
+
+ assert(count);
+ ztBlocksFree += count;
+
+ // merge with preceding
+ merge = (index + count);
+ if ((merge < ztBlocksCount)
+ && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
+ && ztBlocks[merge].free) {
+ ZTBDEQ(merge);
+ count += ztBlocks[merge].size;
+ }
+
+ // merge with following
+ merge = (index - 1);
+ if ((merge > ztFreeIndexMax)
+ && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
+ && ztBlocks[merge].free) {
+ size = ztBlocks[merge].size;
+ count += size;
+ index -= size;
+ ZTBDEQ(index);
+ }
+
+ q = ztLog2down(count);
+ if (q > ztFreeIndexMax) {
+ q = ztFreeIndexMax;
+ }
+ w = q;
+ // queue in order of size
+ while (TRUE) {
+ p = ztBlocks[w].next;
+ if (p == q) {
+ break;
+ }
+ if (ztBlocks[p].size >= count) {
+ break;
+ }
+ w = p;
+ }
+ ztBlocks[p].prev = index;
+ ztBlocks[w].next = index;
+
+ // fault in first
+ ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
+
+ // mark first & last with free flag and size
+ ztBlocks[index].free = TRUE;
+ ztBlocks[index].size = count;
+ ztBlocks[index].prev = w;
+ ztBlocks[index].next = p;
+ if (count > 1) {
+ index += (count - 1);
+ // fault in last
+ ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
+ ztBlocks[index].free = TRUE;
+ ztBlocks[index].size = count;
+ }
+}
+
+static uint32_t
+ztAlloc(zone_t zone, uint32_t count)
+{
+ uint32_t q, w, p, leftover;
+
+ assert(count);
+
+ q = ztLog2up(count);
+ if (q > ztFreeIndexMax) {
+ q = ztFreeIndexMax;
+ }
+ do{
+ w = q;
+ while (TRUE) {
+ p = ztBlocks[w].next;
+ if (p == q) {
+ break;
+ }
+ if (ztBlocks[p].size >= count) {
+ // dequeue, mark both ends allocated
+ ztBlocks[w].next = ztBlocks[p].next;
+ ztBlocks[ztBlocks[p].next].prev = w;
+ ztBlocks[p].free = FALSE;
+ ztBlocksFree -= ztBlocks[p].size;
+ if (ztBlocks[p].size > 1) {
+ ztBlocks[p + ztBlocks[p].size - 1].free = FALSE;
+ }
+
+ // fault all the allocation
+ ztFault(zone_tags_map, &ztBlocks[p], count * sizeof(ztBlocks[p]), 0);
+ // mark last as allocated
+ if (count > 1) {
+ ztBlocks[p + count - 1].free = FALSE;
+ }
+ // free remainder
+ leftover = ztBlocks[p].size - count;
+ if (leftover) {
+ ztFree(zone, p + ztBlocks[p].size - leftover, leftover);
+ }
+
+ return p;
+ }
+ w = p;
+ }
+ q++;
+ }while (q <= ztFreeIndexMax);
+
+ return -1U;
+}
+
+static void
+ztInit(vm_size_t max_zonemap_size, lck_grp_t * group)
+{
+ kern_return_t ret;
+ vm_map_kernel_flags_t vmk_flags;
+ uint32_t idx;
+
+ lck_mtx_init(&ztLock, group, LCK_ATTR_NULL);
+
+ // allocate submaps VM_KERN_MEMORY_DIAG
+
+ zone_tagbase_map_size = atop(max_zonemap_size) * sizeof(uint32_t);
+ vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+ vmk_flags.vmkf_permanent = TRUE;
+ ret = kmem_suballoc(kernel_map, &zone_tagbase_min, zone_tagbase_map_size,
+ FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
+ &zone_tagbase_map);
+
+ if (ret != KERN_SUCCESS) {
+ panic("zone_init: kmem_suballoc failed");
+ }
+ zone_tagbase_max = zone_tagbase_min + round_page(zone_tagbase_map_size);
+
+ zone_tags_map_size = 2048 * 1024 * sizeof(vm_tag_t);
+ vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+ vmk_flags.vmkf_permanent = TRUE;
+ ret = kmem_suballoc(kernel_map, &zone_tags_min, zone_tags_map_size,
+ FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
+ &zone_tags_map);
+
+ if (ret != KERN_SUCCESS) {
+ panic("zone_init: kmem_suballoc failed");
+ }
+ zone_tags_max = zone_tags_min + round_page(zone_tags_map_size);
+
+ ztBlocks = (ztBlock *) zone_tags_min;
+ ztBlocksCount = (uint32_t)(zone_tags_map_size / sizeof(ztBlock));
+
+ // initialize the qheads
+ lck_mtx_lock(&ztLock);
+
+ ztFault(zone_tags_map, &ztBlocks[0], sizeof(ztBlocks[0]), 0);
+ for (idx = 0; idx < ztFreeIndexCount; idx++) {
+ ztBlocks[idx].free = TRUE;
+ ztBlocks[idx].next = idx;
+ ztBlocks[idx].prev = idx;
+ ztBlocks[idx].size = 0;
+ }
+ // free remaining space
+ ztFree(NULL, ztFreeIndexCount, ztBlocksCount - ztFreeIndexCount);
+
+ lck_mtx_unlock(&ztLock);
+}
+
+static void
+ztMemoryAdd(zone_t zone, vm_offset_t mem, vm_size_t size)
+{
+ uint32_t * tagbase;
+ uint32_t count, block, blocks, idx;
+ size_t pages;
+
+ pages = atop(size);
+ tagbase = ZTAGBASE(zone, mem);
+
+ lck_mtx_lock(&ztLock);
+
+ // fault tagbase
+ ztFault(zone_tagbase_map, tagbase, pages * sizeof(uint32_t), 0);
+
+ if (!zone->tags_inline) {
+ // allocate tags
+ count = (uint32_t)(size / zone->elem_size);
+ blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
+ block = ztAlloc(zone, blocks);
+ if (-1U == block) {
+ ztDump(false);
+ }
+ assert(-1U != block);
+ }
+
+ lck_mtx_unlock(&ztLock);
+
+ if (!zone->tags_inline) {
+ // set tag base for each page
+ block *= ztTagsPerBlock;
+ for (idx = 0; idx < pages; idx++) {
+ tagbase[idx] = block + (uint32_t)((ptoa(idx) + (zone->elem_size - 1)) / zone->elem_size);
+ }
+ }
+}
+
+static void
+ztMemoryRemove(zone_t zone, vm_offset_t mem, vm_size_t size)
+{
+ uint32_t * tagbase;
+ uint32_t count, block, blocks, idx;
+ size_t pages;
+
+ // set tag base for each page
+ pages = atop(size);
+ tagbase = ZTAGBASE(zone, mem);
+ block = tagbase[0];
+ for (idx = 0; idx < pages; idx++) {
+ tagbase[idx] = 0xFFFFFFFF;
+ }
+
+ lck_mtx_lock(&ztLock);
+ if (!zone->tags_inline) {
+ count = (uint32_t)(size / zone->elem_size);
+ blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
+ assert(block != 0xFFFFFFFF);
+ block /= ztTagsPerBlock;
+ ztFree(NULL /* zone is unlocked */, block, blocks);
+ }
+
+ lck_mtx_unlock(&ztLock);
+}
+
+uint32_t
+zone_index_from_tag_index(uint32_t tag_zone_index, vm_size_t * elem_size)
+{
+ zone_t z;
+ uint32_t idx;
+
+ simple_lock(&all_zones_lock, &zone_locks_grp);
+
+ for (idx = 0; idx < num_zones; idx++) {
+ z = &(zone_array[idx]);
+ if (!z->tags) {
+ continue;
+ }
+ if (tag_zone_index != z->tag_zone_index) {
+ continue;
+ }
+ *elem_size = z->elem_size;
+ break;
+ }
+
+ simple_unlock(&all_zones_lock);
+
+ if (idx == num_zones) {
+ idx = -1U;
+ }
+
+ return idx;
+}
+
+#endif /* VM_MAX_TAG_ZONES */
+
+/* Routine to get the size of a zone allocated address. If the address doesnt belong to the
+ * zone_map, returns 0.
+ */
+vm_size_t
+zone_element_size(void *addr, zone_t *z)
+{
+ struct zone *src_zone;
+ if (from_zone_map(addr, sizeof(void *))) {
+ struct zone_page_metadata *page_meta = get_zone_page_metadata((struct zone_free_element *)addr, FALSE);
+ src_zone = PAGE_METADATA_GET_ZONE(page_meta);
+ if (z) {
+ *z = src_zone;
+ }
+ return src_zone->elem_size;
+ } else {
+#if CONFIG_GZALLOC
+ vm_size_t gzsize;
+ if (gzalloc_element_size(addr, z, &gzsize)) {
+ return gzsize;
+ }
+#endif /* CONFIG_GZALLOC */
+
+ return 0;
+ }
+}
+
+#if DEBUG || DEVELOPMENT
+
+vm_size_t
+zone_element_info(void *addr, vm_tag_t * ptag)
+{
+ vm_size_t size = 0;
+ vm_tag_t tag = VM_KERN_MEMORY_NONE;
+ struct zone * src_zone;
+
+ if (from_zone_map(addr, sizeof(void *))) {
+ struct zone_page_metadata *page_meta = get_zone_page_metadata((struct zone_free_element *)addr, FALSE);
+ src_zone = PAGE_METADATA_GET_ZONE(page_meta);
+#if VM_MAX_TAG_ZONES
+ if (__improbable(src_zone->tags)) {
+ tag = (ZTAG(src_zone, (vm_offset_t) addr)[0] >> 1);
+ }
+#endif /* VM_MAX_TAG_ZONES */
+ size = src_zone->elem_size;
+ } else {
+#if CONFIG_GZALLOC
+ gzalloc_element_size(addr, NULL, &size);
+#endif /* CONFIG_GZALLOC */
+ }
+ *ptag = tag;
+ return size;
+}
+
+#endif /* DEBUG || DEVELOPMENT */
+
+/*
+ * Zone checking helper function.
+ * A pointer that satisfies these conditions is OK to be a freelist next pointer
+ * A pointer that doesn't satisfy these conditions indicates corruption
+ */
+static inline boolean_t
+is_sane_zone_ptr(zone_t zone,
+ vm_offset_t addr,
+ size_t obj_size)
+{
+ /* Must be aligned to pointer boundary */
+ if (__improbable((addr & (sizeof(vm_offset_t) - 1)) != 0)) {
+ return FALSE;
+ }
+
+ /* Must be a kernel address */
+ if (__improbable(!pmap_kernel_va(addr))) {
+ return FALSE;
+ }
+
+ /* Must be from zone map if the zone only uses memory from the zone_map */
+ /*
+ * TODO: Remove the zone->collectable check when every
+ * zone using foreign memory is properly tagged with allows_foreign
+ */
+ if (zone->collectable && !zone->allows_foreign) {
+ /* check if addr is from zone map */
+ if (addr >= zone_map_min_address &&
+ (addr + obj_size - 1) < zone_map_max_address) {
+ return TRUE;
+ }
+
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+static inline boolean_t
+is_sane_zone_page_metadata(zone_t zone,
+ vm_offset_t page_meta)
+{
+ /* NULL page metadata structures are invalid */
+ if (page_meta == 0) {
+ return FALSE;
+ }
+ return is_sane_zone_ptr(zone, page_meta, sizeof(struct zone_page_metadata));
+}
+
+static inline boolean_t
+is_sane_zone_element(zone_t zone,
+ vm_offset_t addr)
+{
+ /* NULL is OK because it indicates the tail of the list */
+ if (addr == 0) {
+ return TRUE;
+ }
+ return is_sane_zone_ptr(zone, addr, zone->elem_size);
+}
+
+/* Someone wrote to freed memory. */
+__dead2
+static inline void
+zone_element_was_modified_panic(zone_t zone,
+ vm_offset_t element,
+ vm_offset_t found,
+ vm_offset_t expected,
+ vm_offset_t offset)
+{
+ panic("a freed zone element has been modified in zone %s: expected %p but found %p, bits changed %p, at offset %d of %d in element %p, cookies %p %p",
+ zone->zone_name,
+ (void *) expected,
+ (void *) found,
+ (void *) (expected ^ found),
+ (uint32_t) offset,
+ (uint32_t) zone->elem_size,
+ (void *) element,
+ (void *) zp_nopoison_cookie,
+ (void *) zp_poisoned_cookie);
+}
+
+/*
+ * The primary and backup pointers don't match.
+ * Determine which one was likely the corrupted pointer, find out what it
+ * probably should have been, and panic.
+ */
+__dead2
+static void
+backup_ptr_mismatch_panic(zone_t zone,
+ vm_offset_t element,
+ vm_offset_t primary,
+ vm_offset_t backup)
+{
+ vm_offset_t likely_backup;
+ vm_offset_t likely_primary;
+
+ likely_primary = primary ^ zp_nopoison_cookie;
+ boolean_t sane_backup;
+ boolean_t sane_primary = is_sane_zone_element(zone, likely_primary);
+ boolean_t element_was_poisoned = (backup & 0x1) ? TRUE : FALSE;
+
+#if defined(__LP64__)
+ /* We can inspect the tag in the upper bits for additional confirmation */
+ if ((backup & 0xFFFFFF0000000000) == 0xFACADE0000000000) {
+ element_was_poisoned = TRUE;
+ } else if ((backup & 0xFFFFFF0000000000) == 0xC0FFEE0000000000) {
+ element_was_poisoned = FALSE;
+ }
+#endif
+
+ if (element_was_poisoned) {
+ likely_backup = backup ^ zp_poisoned_cookie;
+ sane_backup = is_sane_zone_element(zone, likely_backup);
+ } else {
+ likely_backup = backup ^ zp_nopoison_cookie;
+ sane_backup = is_sane_zone_element(zone, likely_backup);
+ }
+
+ /* The primary is definitely the corrupted one */
+ if (!sane_primary && sane_backup) {
+ zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
+ }
+
+ /* The backup is definitely the corrupted one */
+ if (sane_primary && !sane_backup) {
+ zone_element_was_modified_panic(zone, element, backup,
+ (likely_primary ^ (element_was_poisoned ? zp_poisoned_cookie : zp_nopoison_cookie)),
+ zone->elem_size - sizeof(vm_offset_t));
+ }
+
+ /*
+ * Not sure which is the corrupted one.
+ * It's less likely that the backup pointer was overwritten with
+ * ( (sane address) ^ (valid cookie) ), so we'll guess that the
+ * primary pointer has been overwritten with a sane but incorrect address.
+ */
+ if (sane_primary && sane_backup) {
+ zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
+ }
+
+ /* Neither are sane, so just guess. */
+ zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
+}
+
+/*
+ * Adds the element to the head of the zone's free list
+ * Keeps a backup next-pointer at the end of the element
+ */
+static inline void
+free_to_zone(zone_t zone,
+ vm_offset_t element,
+ boolean_t poison)
+{
+ vm_offset_t old_head;
+ struct zone_page_metadata *page_meta;
+
+ vm_offset_t *primary = (vm_offset_t *) element;
+ vm_offset_t *backup = get_backup_ptr(zone->elem_size, primary);
+
+ page_meta = get_zone_page_metadata((struct zone_free_element *)element, FALSE);
+ assert(PAGE_METADATA_GET_ZONE(page_meta) == zone);
+ old_head = (vm_offset_t)page_metadata_get_freelist(page_meta);
+
+ if (__improbable(!is_sane_zone_element(zone, old_head))) {
+ panic("zfree: invalid head pointer %p for freelist of zone %s\n",
+ (void *) old_head, zone->zone_name);
+ }
+
+ if (__improbable(!is_sane_zone_element(zone, element))) {
+ panic("zfree: freeing invalid pointer %p to zone %s\n",
+ (void *) element, zone->zone_name);
+ }
+
+ if (__improbable(old_head == element)) {
+ panic("zfree: double free of %p to zone %s\n",
+ (void *) element, zone->zone_name);
+ }
+ /*
+ * Always write a redundant next pointer
+ * So that it is more difficult to forge, xor it with a random cookie
+ * A poisoned element is indicated by using zp_poisoned_cookie
+ * instead of zp_nopoison_cookie
+ */
+
+ *backup = old_head ^ (poison ? zp_poisoned_cookie : zp_nopoison_cookie);
+
+ /*
+ * Insert this element at the head of the free list. We also xor the
+ * primary pointer with the zp_nopoison_cookie to make sure a free
+ * element does not provide the location of the next free element directly.
+ */
+ *primary = old_head ^ zp_nopoison_cookie;
+ page_metadata_set_freelist(page_meta, (struct zone_free_element *)element);
+ page_meta->free_count++;
+ if (zone->allows_foreign && !from_zone_map(element, zone->elem_size)) {
+ if (page_meta->free_count == 1) {
+ /* first foreign element freed on page, move from all_used */
+ re_queue_tail(&zone->pages.any_free_foreign, &(page_meta->pages));
+ } else {
+ /* no other list transitions */
+ }
+ } else if (page_meta->free_count == get_metadata_alloc_count(page_meta)) {
+ /* whether the page was on the intermediate or all_used, queue, move it to free */
+ re_queue_tail(&zone->pages.all_free, &(page_meta->pages));
+ zone->count_all_free_pages += page_meta->page_count;
+ } else if (page_meta->free_count == 1) {
+ /* first free element on page, move from all_used */
+ re_queue_tail(&zone->pages.intermediate, &(page_meta->pages));
+ }
+ zone->count--;
+ zone->countfree++;
+
+#if KASAN_ZALLOC
+ kasan_poison_range(element, zone->elem_size, ASAN_HEAP_FREED);
+#endif
+}
+
+
+/*
+ * Removes an element from the zone's free list, returning 0 if the free list is empty.
+ * Verifies that the next-pointer and backup next-pointer are intact,
+ * and verifies that a poisoned element hasn't been modified.
+ */
+static inline vm_offset_t
+try_alloc_from_zone(zone_t zone,
+ vm_tag_t tag __unused,
+ boolean_t* check_poison)
+{
+ vm_offset_t element;
+ struct zone_page_metadata *page_meta;
+
+ *check_poison = FALSE;
+
+ /* if zone is empty, bail */
+ if (zone->allows_foreign && !queue_empty(&zone->pages.any_free_foreign)) {
+ page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.any_free_foreign);
+ } else if (!queue_empty(&zone->pages.intermediate)) {
+ page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.intermediate);
+ } else if (!queue_empty(&zone->pages.all_free)) {
+ page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.all_free);
+ assert(zone->count_all_free_pages >= page_meta->page_count);
+ zone->count_all_free_pages -= page_meta->page_count;
+ } else {
+ return 0;
+ }
+ /* Check if page_meta passes is_sane_zone_element */
+ if (__improbable(!is_sane_zone_page_metadata(zone, (vm_offset_t)page_meta))) {
+ panic("zalloc: invalid metadata structure %p for freelist of zone %s\n",
+ (void *) page_meta, zone->zone_name);
+ }
+ assert(PAGE_METADATA_GET_ZONE(page_meta) == zone);
+ element = (vm_offset_t)page_metadata_get_freelist(page_meta);
+
+ if (__improbable(!is_sane_zone_ptr(zone, element, zone->elem_size))) {
+ panic("zfree: invalid head pointer %p for freelist of zone %s\n",
+ (void *) element, zone->zone_name);
+ }
+
+ vm_offset_t *primary = (vm_offset_t *) element;
+ vm_offset_t *backup = get_backup_ptr(zone->elem_size, primary);
+
+ /*
+ * Since the primary next pointer is xor'ed with zp_nopoison_cookie
+ * for obfuscation, retrieve the original value back
+ */
+ vm_offset_t next_element = *primary ^ zp_nopoison_cookie;
+ vm_offset_t next_element_primary = *primary;
+ vm_offset_t next_element_backup = *backup;
+
+ /*
+ * backup_ptr_mismatch_panic will determine what next_element
+ * should have been, and print it appropriately
+ */
+ if (__improbable(!is_sane_zone_element(zone, next_element))) {
+ backup_ptr_mismatch_panic(zone, element, next_element_primary, next_element_backup);
+ }
+
+ /* Check the backup pointer for the regular cookie */
+ if (__improbable(next_element != (next_element_backup ^ zp_nopoison_cookie))) {
+ /* Check for the poisoned cookie instead */
+ if (__improbable(next_element != (next_element_backup ^ zp_poisoned_cookie))) {
+ /* Neither cookie is valid, corruption has occurred */
+ backup_ptr_mismatch_panic(zone, element, next_element_primary, next_element_backup);
+ }
+
+ /*
+ * Element was marked as poisoned, so check its integrity before using it.
+ */
+ *check_poison = TRUE;
+ }
+
+ /* Make sure the page_meta is at the correct offset from the start of page */
+ if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)element, FALSE))) {
+ panic("zalloc: Incorrect metadata %p found in zone %s page queue. Expected metadata: %p\n",
+ page_meta, zone->zone_name, get_zone_page_metadata((struct zone_free_element *)element, FALSE));
+ }
+
+ /* Make sure next_element belongs to the same page as page_meta */
+ if (next_element) {
+ if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)next_element, FALSE))) {
+ panic("zalloc: next element pointer %p for element %p points to invalid element for zone %s\n",
+ (void *)next_element, (void *)element, zone->zone_name);
+ }
+ }
+
+ /* Remove this element from the free list */
+ page_metadata_set_freelist(page_meta, (struct zone_free_element *)next_element);
+ page_meta->free_count--;
+
+ if (page_meta->free_count == 0) {
+ /* move to all used */
+ re_queue_tail(&zone->pages.all_used, &(page_meta->pages));
+ } else {
+ if (!zone->allows_foreign || from_zone_map(element, zone->elem_size)) {
+ if (get_metadata_alloc_count(page_meta) == page_meta->free_count + 1) {
+ /* remove from free, move to intermediate */
+ re_queue_tail(&zone->pages.intermediate, &(page_meta->pages));
+ }
+ }
+ }
+ zone->countfree--;
+ zone->count++;
+ zone->sum_count++;
+
+#if VM_MAX_TAG_ZONES
+ if (__improbable(zone->tags)) {
+ // set the tag with b0 clear so the block remains inuse
+ ZTAG(zone, element)[0] = (tag << 1);
+ }
+#endif /* VM_MAX_TAG_ZONES */
+
+
+#if KASAN_ZALLOC
+ kasan_poison_range(element, zone->elem_size, ASAN_VALID);
+#endif
+
+ return element;
+}
+
+/*
+ * End of zone poisoning
+ */
+
+/*
+ * Zone info options
+ */
+#define ZINFO_SLOTS MAX_ZONES /* for now */
+
+zone_t zone_find_largest(void);
+
+/*
+ * Async allocation of zones
+ * This mechanism allows for bootstrapping an empty zone which is setup with
+ * non-blocking flags. The first call to zalloc_noblock() will kick off a thread_call
+ * to zalloc_async. We perform a zalloc() (which may block) and then an immediate free.
+ * This will prime the zone for the next use.
+ *
+ * Currently the thread_callout function (zalloc_async) will loop through all zones
+ * looking for any zone with async_pending set and do the work for it.
+ *
+ * NOTE: If the calling thread for zalloc_noblock is lower priority than thread_call,
+ * then zalloc_noblock to an empty zone may succeed.
+ */
+void zalloc_async(
+ thread_call_param_t p0,
+ thread_call_param_t p1);
+
+static thread_call_data_t call_async_alloc;
+
+/*
+ * Align elements that use the zone page list to 32 byte boundaries.
+ */
+#define ZONE_ELEMENT_ALIGNMENT 32
+
+#define zone_wakeup(zone) thread_wakeup((event_t)(zone))
+#define zone_sleep(zone) \
+ (void) lck_mtx_sleep(&(zone)->lock, LCK_SLEEP_SPIN_ALWAYS, (event_t)(zone), THREAD_UNINT);
+
+
+#define lock_zone_init(zone) \
+MACRO_BEGIN \
+ lck_attr_setdefault(&(zone)->lock_attr); \
+ lck_mtx_init_ext(&(zone)->lock, &(zone)->lock_ext, \
+ &zone_locks_grp, &(zone)->lock_attr); \
+MACRO_END
+
+#define lock_try_zone(zone) lck_mtx_try_lock_spin(&zone->lock)
+
+/*
+ * Exclude more than one concurrent garbage collection
+ */
+decl_lck_mtx_data(, zone_gc_lock);
+
+lck_attr_t zone_gc_lck_attr;
+lck_grp_t zone_gc_lck_grp;
+lck_grp_attr_t zone_gc_lck_grp_attr;
+lck_mtx_ext_t zone_gc_lck_ext;
+
+boolean_t zone_gc_allowed = TRUE;
+boolean_t panic_include_zprint = FALSE;
+
+mach_memory_info_t *panic_kext_memory_info = NULL;
+vm_size_t panic_kext_memory_size = 0;
+
+#define ZALLOC_DEBUG_ZONEGC 0x00000001
+#define ZALLOC_DEBUG_ZCRAM 0x00000002
+
+#if DEBUG || DEVELOPMENT
+static uint32_t zalloc_debug = 0;
+#endif
+
+/*
+ * Zone leak debugging code
+ *
+ * When enabled, this code keeps a log to track allocations to a particular zone that have not
+ * yet been freed. Examining this log will reveal the source of a zone leak. The log is allocated
+ * only when logging is enabled, so there is no effect on the system when it's turned off. Logging is
+ * off by default.
+ *
+ * Enable the logging via the boot-args. Add the parameter "zlog=<zone>" to boot-args where <zone>
+ * is the name of the zone you wish to log.
+ *
+ * This code only tracks one zone, so you need to identify which one is leaking first.
+ * Generally, you'll know you have a leak when you get a "zalloc retry failed 3" panic from the zone
+ * garbage collector. Note that the zone name printed in the panic message is not necessarily the one
+ * containing the leak. So do a zprint from gdb and locate the zone with the bloated size. This
+ * is most likely the problem zone, so set zlog in boot-args to this zone name, reboot and re-run the test. The
+ * next time it panics with this message, examine the log using the kgmacros zstack, findoldest and countpcs.
+ * See the help in the kgmacros for usage info.
+ *
+ *
+ * Zone corruption logging
+ *
+ * Logging can also be used to help identify the source of a zone corruption. First, identify the zone
+ * that is being corrupted, then add "-zc zlog=<zone name>" to the boot-args. When -zc is used in conjunction
+ * with zlog, it changes the logging style to track both allocations and frees to the zone. So when the
+ * corruption is detected, examining the log will show you the stack traces of the callers who last allocated
+ * and freed any particular element in the zone. Use the findelem kgmacro with the address of the element that's been
+ * corrupted to examine its history. This should lead to the source of the corruption.
+ */
+
+static boolean_t log_records_init = FALSE;
+static int log_records; /* size of the log, expressed in number of records */
+
+#define MAX_NUM_ZONES_ALLOWED_LOGGING 10 /* Maximum 10 zones can be logged at once */
+
+static int max_num_zones_to_log = MAX_NUM_ZONES_ALLOWED_LOGGING;
+static int num_zones_logged = 0;
+
+static char zone_name_to_log[MAX_ZONE_NAME] = ""; /* the zone name we're logging, if any */
+
+/* Log allocations and frees to help debug a zone element corruption */
+boolean_t corruption_debug_flag = DEBUG; /* enabled by "-zc" boot-arg */
+/* Making pointer scanning leaks detection possible for all zones */
+
+#if DEBUG || DEVELOPMENT
+boolean_t leak_scan_debug_flag = FALSE; /* enabled by "-zl" boot-arg */
+#endif /* DEBUG || DEVELOPMENT */
+
+
+/*
+ * The number of records in the log is configurable via the zrecs parameter in boot-args. Set this to
+ * the number of records you want in the log. For example, "zrecs=10" sets it to 10 records. Since this
+ * is the number of stacks suspected of leaking, we don't need many records.
+ */
+
+#if defined(__LP64__)
+#define ZRECORDS_MAX 2560 /* Max records allowed in the log */
+#else
+#define ZRECORDS_MAX 1536 /* Max records allowed in the log */
+#endif
+#define ZRECORDS_DEFAULT 1024 /* default records in log if zrecs is not specificed in boot-args */
+
+/*
+ * Each record in the log contains a pointer to the zone element it refers to,
+ * and a small array to hold the pc's from the stack trace. A
+ * record is added to the log each time a zalloc() is done in the zone_of_interest. For leak debugging,
+ * the record is cleared when a zfree() is done. For corruption debugging, the log tracks both allocs and frees.
+ * If the log fills, old records are replaced as if it were a circular buffer.
+ */
+
+
+/*
+ * Decide if we want to log this zone by doing a string compare between a zone name and the name
+ * of the zone to log. Return true if the strings are equal, false otherwise. Because it's not
+ * possible to include spaces in strings passed in via the boot-args, a period in the logname will
+ * match a space in the zone name.
+ */
+
+int
+track_this_zone(const char *zonename, const char *logname)
+{
+ unsigned int len;
+ const char *zc = zonename;
+ const char *lc = logname;
+
+ /*
+ * Compare the strings. We bound the compare by MAX_ZONE_NAME.
+ */
+
+ for (len = 1; len <= MAX_ZONE_NAME; zc++, lc++, len++) {
+ /*
+ * If the current characters don't match, check for a space in
+ * in the zone name and a corresponding period in the log name.
+ * If that's not there, then the strings don't match.
+ */
+
+ if (*zc != *lc && !(*zc == ' ' && *lc == '.')) {
+ break;
+ }
+
+ /*
+ * The strings are equal so far. If we're at the end, then it's a match.
+ */
+
+ if (*zc == '\0') {
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+
+/*
+ * Test if we want to log this zalloc/zfree event. We log if this is the zone we're interested in and
+ * the buffer for the records has been allocated.
+ */
+
+#define DO_LOGGING(z) (z->zone_logging == TRUE && z->zlog_btlog)
+
+extern boolean_t kmem_alloc_ready;
+
+#if CONFIG_ZLEAKS
+#pragma mark -
+#pragma mark Zone Leak Detection
+
+/*
+ * The zone leak detector, abbreviated 'zleak', keeps track of a subset of the currently outstanding
+ * allocations made by the zone allocator. Every zleak_sample_factor allocations in each zone, we capture a
+ * backtrace. Every free, we examine the table and determine if the allocation was being tracked,
+ * and stop tracking it if it was being tracked.
+ *
+ * We track the allocations in the zallocations hash table, which stores the address that was returned from
+ * the zone allocator. Each stored entry in the zallocations table points to an entry in the ztraces table, which
+ * stores the backtrace associated with that allocation. This provides uniquing for the relatively large
+ * backtraces - we don't store them more than once.
+ *
+ * Data collection begins when the zone map is 50% full, and only occurs for zones that are taking up
+ * a large amount of virtual space.
+ */
+#define ZLEAK_STATE_ENABLED 0x01 /* Zone leak monitoring should be turned on if zone_map fills up. */
+#define ZLEAK_STATE_ACTIVE 0x02 /* We are actively collecting traces. */
+#define ZLEAK_STATE_ACTIVATING 0x04 /* Some thread is doing setup; others should move along. */
+#define ZLEAK_STATE_FAILED 0x08 /* Attempt to allocate tables failed. We will not try again. */
+uint32_t zleak_state = 0; /* State of collection, as above */
+
+boolean_t panic_include_ztrace = FALSE; /* Enable zleak logging on panic */
+vm_size_t zleak_global_tracking_threshold; /* Size of zone map at which to start collecting data */
+vm_size_t zleak_per_zone_tracking_threshold; /* Size a zone will have before we will collect data on it */
+unsigned int zleak_sample_factor = 1000; /* Allocations per sample attempt */
+
+/*
+ * Counters for allocation statistics.
+ */
+
+/* Times two active records want to occupy the same spot */
+unsigned int z_alloc_collisions = 0;
+unsigned int z_trace_collisions = 0;
+
+/* Times a new record lands on a spot previously occupied by a freed allocation */
+unsigned int z_alloc_overwrites = 0;
+unsigned int z_trace_overwrites = 0;
+
+/* Times a new alloc or trace is put into the hash table */
+unsigned int z_alloc_recorded = 0;
+unsigned int z_trace_recorded = 0;
+
+/* Times zleak_log returned false due to not being able to acquire the lock */
+unsigned int z_total_conflicts = 0;
+
+
+#pragma mark struct zallocation
+/*
+ * Structure for keeping track of an allocation
+ * An allocation bucket is in use if its element is not NULL
+ */
+struct zallocation {
+ uintptr_t za_element; /* the element that was zalloc'ed or zfree'ed, NULL if bucket unused */
+ vm_size_t za_size; /* how much memory did this allocation take up? */
+ uint32_t za_trace_index; /* index into ztraces for backtrace associated with allocation */
+ /* TODO: #if this out */
+ uint32_t za_hit_count; /* for determining effectiveness of hash function */
+};
+
+/* Size must be a power of two for the zhash to be able to just mask off bits instead of mod */
+uint32_t zleak_alloc_buckets = CONFIG_ZLEAK_ALLOCATION_MAP_NUM;
+uint32_t zleak_trace_buckets = CONFIG_ZLEAK_TRACE_MAP_NUM;
+
+vm_size_t zleak_max_zonemap_size;
+
+/* Hashmaps of allocations and their corresponding traces */
+static struct zallocation* zallocations;
+static struct ztrace* ztraces;
+
+/* not static so that panic can see this, see kern/debug.c */
+struct ztrace* top_ztrace;
+
+/* Lock to protect zallocations, ztraces, and top_ztrace from concurrent modification. */
+static lck_spin_t zleak_lock;
+static lck_attr_t zleak_lock_attr;
+static lck_grp_t zleak_lock_grp;
+static lck_grp_attr_t zleak_lock_grp_attr;
+
+/*
+ * Initializes the zone leak monitor. Called from zone_init()
+ */
+static void
+zleak_init(vm_size_t max_zonemap_size)
+{
+ char scratch_buf[16];
+ boolean_t zleak_enable_flag = FALSE;
+
+ zleak_max_zonemap_size = max_zonemap_size;
+ zleak_global_tracking_threshold = max_zonemap_size / 2;
+ zleak_per_zone_tracking_threshold = zleak_global_tracking_threshold / 8;
+
+#if CONFIG_EMBEDDED
+ if (PE_parse_boot_argn("-zleakon", scratch_buf, sizeof(scratch_buf))) {
+ zleak_enable_flag = TRUE;
+ printf("zone leak detection enabled\n");
+ } else {
+ zleak_enable_flag = FALSE;
+ printf("zone leak detection disabled\n");
+ }
+#else /* CONFIG_EMBEDDED */
+ /* -zleakoff (flag to disable zone leak monitor) */
+ if (PE_parse_boot_argn("-zleakoff", scratch_buf, sizeof(scratch_buf))) {
+ zleak_enable_flag = FALSE;
+ printf("zone leak detection disabled\n");
+ } else {
+ zleak_enable_flag = TRUE;
+ printf("zone leak detection enabled\n");
+ }
+#endif /* CONFIG_EMBEDDED */
+
+ /* zfactor=XXXX (override how often to sample the zone allocator) */
+ if (PE_parse_boot_argn("zfactor", &zleak_sample_factor, sizeof(zleak_sample_factor))) {
+ printf("Zone leak factor override: %u\n", zleak_sample_factor);
+ }
+
+ /* zleak-allocs=XXXX (override number of buckets in zallocations) */
+ if (PE_parse_boot_argn("zleak-allocs", &zleak_alloc_buckets, sizeof(zleak_alloc_buckets))) {
+ printf("Zone leak alloc buckets override: %u\n", zleak_alloc_buckets);
+ /* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
+ if (zleak_alloc_buckets == 0 || (zleak_alloc_buckets & (zleak_alloc_buckets - 1))) {
+ printf("Override isn't a power of two, bad things might happen!\n");
+ }
+ }
+
+ /* zleak-traces=XXXX (override number of buckets in ztraces) */
+ if (PE_parse_boot_argn("zleak-traces", &zleak_trace_buckets, sizeof(zleak_trace_buckets))) {
+ printf("Zone leak trace buckets override: %u\n", zleak_trace_buckets);
+ /* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
+ if (zleak_trace_buckets == 0 || (zleak_trace_buckets & (zleak_trace_buckets - 1))) {
+ printf("Override isn't a power of two, bad things might happen!\n");
+ }
+ }
+
+ /* allocate the zleak_lock */
+ lck_grp_attr_setdefault(&zleak_lock_grp_attr);
+ lck_grp_init(&zleak_lock_grp, "zleak_lock", &zleak_lock_grp_attr);
+ lck_attr_setdefault(&zleak_lock_attr);
+ lck_spin_init(&zleak_lock, &zleak_lock_grp, &zleak_lock_attr);
+
+ if (zleak_enable_flag) {
+ zleak_state = ZLEAK_STATE_ENABLED;
+ }
+}
+
+#if CONFIG_ZLEAKS
+
+/*
+ * Support for kern.zleak.active sysctl - a simplified
+ * version of the zleak_state variable.
+ */
+int
+get_zleak_state(void)
+{
+ if (zleak_state & ZLEAK_STATE_FAILED) {
+ return -1;
+ }
+ if (zleak_state & ZLEAK_STATE_ACTIVE) {
+ return 1;
+ }
+ return 0;
+}
+
+#endif
+
+
+kern_return_t
+zleak_activate(void)
+{
+ kern_return_t retval;
+ vm_size_t z_alloc_size = zleak_alloc_buckets * sizeof(struct zallocation);
+ vm_size_t z_trace_size = zleak_trace_buckets * sizeof(struct ztrace);
+ void *allocations_ptr = NULL;
+ void *traces_ptr = NULL;
+
+ /* Only one thread attempts to activate at a time */
+ if (zleak_state & (ZLEAK_STATE_ACTIVE | ZLEAK_STATE_ACTIVATING | ZLEAK_STATE_FAILED)) {
+ return KERN_SUCCESS;
+ }
+
+ /* Indicate that we're doing the setup */
+ lck_spin_lock(&zleak_lock);
+ if (zleak_state & (ZLEAK_STATE_ACTIVE | ZLEAK_STATE_ACTIVATING | ZLEAK_STATE_FAILED)) {
+ lck_spin_unlock(&zleak_lock);
+ return KERN_SUCCESS;
+ }
+
+ zleak_state |= ZLEAK_STATE_ACTIVATING;
+ lck_spin_unlock(&zleak_lock);
+
+ /* Allocate and zero tables */
+ retval = kmem_alloc_kobject(kernel_map, (vm_offset_t*)&allocations_ptr, z_alloc_size, VM_KERN_MEMORY_OSFMK);
+ if (retval != KERN_SUCCESS) {
+ goto fail;
+ }
+
+ retval = kmem_alloc_kobject(kernel_map, (vm_offset_t*)&traces_ptr, z_trace_size, VM_KERN_MEMORY_OSFMK);
+ if (retval != KERN_SUCCESS) {
+ goto fail;
+ }
+
+ bzero(allocations_ptr, z_alloc_size);
+ bzero(traces_ptr, z_trace_size);
+
+ /* Everything's set. Install tables, mark active. */
+ zallocations = allocations_ptr;
+ ztraces = traces_ptr;
+
+ /*
+ * Initialize the top_ztrace to the first entry in ztraces,
+ * so we don't have to check for null in zleak_log
+ */
+ top_ztrace = &ztraces[0];
+
+ /*
+ * Note that we do need a barrier between installing
+ * the tables and setting the active flag, because the zfree()
+ * path accesses the table without a lock if we're active.
+ */
+ lck_spin_lock(&zleak_lock);
+ zleak_state |= ZLEAK_STATE_ACTIVE;
+ zleak_state &= ~ZLEAK_STATE_ACTIVATING;
+ lck_spin_unlock(&zleak_lock);
+
+ return 0;
+
+fail:
+ /*
+ * If we fail to allocate memory, don't further tax
+ * the system by trying again.
+ */
+ lck_spin_lock(&zleak_lock);
+ zleak_state |= ZLEAK_STATE_FAILED;
+ zleak_state &= ~ZLEAK_STATE_ACTIVATING;
+ lck_spin_unlock(&zleak_lock);
+
+ if (allocations_ptr != NULL) {
+ kmem_free(kernel_map, (vm_offset_t)allocations_ptr, z_alloc_size);
+ }
+
+ if (traces_ptr != NULL) {
+ kmem_free(kernel_map, (vm_offset_t)traces_ptr, z_trace_size);
+ }
+
+ return retval;
+}
+
+/*
+ * TODO: What about allocations that never get deallocated,
+ * especially ones with unique backtraces? Should we wait to record
+ * until after boot has completed?
+ * (How many persistent zallocs are there?)
+ */
+
+/*
+ * This function records the allocation in the allocations table,
+ * and stores the associated backtrace in the traces table
+ * (or just increments the refcount if the trace is already recorded)
+ * If the allocation slot is in use, the old allocation is replaced with the new allocation, and
+ * the associated trace's refcount is decremented.
+ * If the trace slot is in use, it returns.
+ * The refcount is incremented by the amount of memory the allocation consumes.
+ * The return value indicates whether to try again next time.
+ */
+static boolean_t
+zleak_log(uintptr_t* bt,
+ uintptr_t addr,
+ uint32_t depth,
+ vm_size_t allocation_size)
+{
+ /* Quit if there's someone else modifying the hash tables */
+ if (!lck_spin_try_lock(&zleak_lock)) {
+ z_total_conflicts++;
+ return FALSE;
+ }
+
+ struct zallocation* allocation = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
+
+ uint32_t trace_index = hashbacktrace(bt, depth, zleak_trace_buckets);
+ struct ztrace* trace = &ztraces[trace_index];
+
+ allocation->za_hit_count++;
+ trace->zt_hit_count++;
+
+ /*
+ * If the allocation bucket we want to be in is occupied, and if the occupier
+ * has the same trace as us, just bail.
+ */
+ if (allocation->za_element != (uintptr_t) 0 && trace_index == allocation->za_trace_index) {
+ z_alloc_collisions++;
+
+ lck_spin_unlock(&zleak_lock);
+ return TRUE;
+ }
+
+ /* STEP 1: Store the backtrace in the traces array. */
+ /* A size of zero indicates that the trace bucket is free. */
+
+ if (trace->zt_size > 0 && bcmp(trace->zt_stack, bt, (depth * sizeof(uintptr_t))) != 0) {
+ /*
+ * Different unique trace with same hash!
+ * Just bail - if we're trying to record the leaker, hopefully the other trace will be deallocated
+ * and get out of the way for later chances
+ */
+ trace->zt_collisions++;
+ z_trace_collisions++;
+
+ lck_spin_unlock(&zleak_lock);
+ return TRUE;
+ } else if (trace->zt_size > 0) {
+ /* Same trace, already added, so increment refcount */
+ trace->zt_size += allocation_size;
+ } else {
+ /* Found an unused trace bucket, record the trace here! */
+ if (trace->zt_depth != 0) { /* if this slot was previously used but not currently in use */
+ z_trace_overwrites++;
+ }
+
+ z_trace_recorded++;
+ trace->zt_size = allocation_size;
+ memcpy(trace->zt_stack, bt, (depth * sizeof(uintptr_t)));
+
+ trace->zt_depth = depth;
+ trace->zt_collisions = 0;
+ }
+
+ /* STEP 2: Store the allocation record in the allocations array. */
+
+ if (allocation->za_element != (uintptr_t) 0) {
+ /*
+ * Straight up replace any allocation record that was there. We don't want to do the work
+ * to preserve the allocation entries that were there, because we only record a subset of the
+ * allocations anyways.
+ */
+
+ z_alloc_collisions++;
+
+ struct ztrace* associated_trace = &ztraces[allocation->za_trace_index];
+ /* Knock off old allocation's size, not the new allocation */
+ associated_trace->zt_size -= allocation->za_size;
+ } else if (allocation->za_trace_index != 0) {
+ /* Slot previously used but not currently in use */
+ z_alloc_overwrites++;
+ }
+
+ allocation->za_element = addr;
+ allocation->za_trace_index = trace_index;
+ allocation->za_size = allocation_size;
+
+ z_alloc_recorded++;
+
+ if (top_ztrace->zt_size < trace->zt_size) {
+ top_ztrace = trace;
+ }
+
+ lck_spin_unlock(&zleak_lock);
+ return TRUE;
+}
+
+/*
+ * Free the allocation record and release the stacktrace.
+ * This should be as fast as possible because it will be called for every free.
+ */
+static void
+zleak_free(uintptr_t addr,
+ vm_size_t allocation_size)
+{
+ if (addr == (uintptr_t) 0) {
+ return;
+ }
+
+ struct zallocation* allocation = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
+
+ /* Double-checked locking: check to find out if we're interested, lock, check to make
+ * sure it hasn't changed, then modify it, and release the lock.
+ */
+
+ if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
+ /* if the allocation was the one, grab the lock, check again, then delete it */
+ lck_spin_lock(&zleak_lock);
+
+ if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
+ struct ztrace *trace;
+
+ /* allocation_size had better match what was passed into zleak_log - otherwise someone is freeing into the wrong zone! */
+ if (allocation->za_size != allocation_size) {
+ panic("Freeing as size %lu memory that was allocated with size %lu\n",
+ (uintptr_t)allocation_size, (uintptr_t)allocation->za_size);
+ }
+
+ trace = &ztraces[allocation->za_trace_index];
+
+ /* size of 0 indicates trace bucket is unused */
+ if (trace->zt_size > 0) {
+ trace->zt_size -= allocation_size;
+ }
+
+ /* A NULL element means the allocation bucket is unused */
+ allocation->za_element = 0;
+ }
+ lck_spin_unlock(&zleak_lock);
+ }
+}
+
+#endif /* CONFIG_ZLEAKS */
+
+/* These functions outside of CONFIG_ZLEAKS because they are also used in
+ * mbuf.c for mbuf leak-detection. This is why they lack the z_ prefix.
+ */
+
+/* "Thomas Wang's 32/64 bit mix functions." http://www.concentric.net/~Ttwang/tech/inthash.htm */
+uintptr_t
+hash_mix(uintptr_t x)
+{
+#ifndef __LP64__
+ x += ~(x << 15);
+ x ^= (x >> 10);
+ x += (x << 3);
+ x ^= (x >> 6);
+ x += ~(x << 11);
+ x ^= (x >> 16);
+#else
+ x += ~(x << 32);
+ x ^= (x >> 22);
+ x += ~(x << 13);
+ x ^= (x >> 8);
+ x += (x << 3);
+ x ^= (x >> 15);
+ x += ~(x << 27);
+ x ^= (x >> 31);
+#endif
+ return x;
+}
+
+uint32_t
+hashbacktrace(uintptr_t* bt, uint32_t depth, uint32_t max_size)
+{
+ uintptr_t hash = 0;
+ uintptr_t mask = max_size - 1;
+
+ while (depth) {
+ hash += bt[--depth];
+ }
+
+ hash = hash_mix(hash) & mask;
+
+ assert(hash < max_size);
+
+ return (uint32_t) hash;
+}
+
+/*
+ * TODO: Determine how well distributed this is
+ * max_size must be a power of 2. i.e 0x10000 because 0x10000-1 is 0x0FFFF which is a great bitmask
+ */
+uint32_t
+hashaddr(uintptr_t pt, uint32_t max_size)
+{
+ uintptr_t hash = 0;
+ uintptr_t mask = max_size - 1;
+
+ hash = hash_mix(pt) & mask;
+
+ assert(hash < max_size);
+
+ return (uint32_t) hash;
+}
+
+/* End of all leak-detection code */
+#pragma mark -
+
+#define ZONE_MAX_ALLOC_SIZE (32 * 1024)
+#define ZONE_ALLOC_FRAG_PERCENT(alloc_size, ele_size) (((alloc_size % ele_size) * 100) / alloc_size)
+
+/* Used to manage copying in of new zone names */
+static vm_offset_t zone_names_start;
+static vm_offset_t zone_names_next;
+
+static vm_size_t
+compute_element_size(vm_size_t requested_size)
+{
+ vm_size_t element_size = requested_size;
+
+ /* Zone elements must fit both a next pointer and a backup pointer */
+ vm_size_t minimum_element_size = sizeof(vm_offset_t) * 2;
+ if (element_size < minimum_element_size) {
+ element_size = minimum_element_size;
+ }
+
+ /*
+ * Round element size to a multiple of sizeof(pointer)
+ * This also enforces that allocations will be aligned on pointer boundaries
+ */
+ element_size = ((element_size - 1) + sizeof(vm_offset_t)) -
+ ((element_size - 1) % sizeof(vm_offset_t));
+
+ return element_size;
+}
+
+#if KASAN_ZALLOC
+
+/*
+ * Called from zinit().
+ *
+ * Fixes up the zone's element size to incorporate the redzones.
+ */
+static void
+kasan_update_element_size_for_redzone(
+ zone_t zone, /* the zone that needs to be updated */
+ vm_size_t *size, /* requested zone element size */
+ vm_size_t *max, /* maximum memory to use */
+ const char *name) /* zone name */
+{
+ /* Expand the zone allocation size to include the redzones. For page-multiple
+ * zones add a full guard page because they likely require alignment. kalloc
+ * and fakestack handles its own KASan state, so ignore those zones. */
+ /* XXX: remove this when zinit_with_options() is a thing */
+ const char *kalloc_name = "kalloc.";
+ const char *fakestack_name = "fakestack.";
+ if (strncmp(name, kalloc_name, strlen(kalloc_name)) == 0) {
+ zone->kasan_redzone = 0;
+ } else if (strncmp(name, fakestack_name, strlen(fakestack_name)) == 0) {
+ zone->kasan_redzone = 0;
+ } else {
+ if ((*size % PAGE_SIZE) != 0) {
+ zone->kasan_redzone = KASAN_GUARD_SIZE;
+ } else {
+ zone->kasan_redzone = PAGE_SIZE;
+ }
+ *max = (*max / *size) * (*size + zone->kasan_redzone * 2);
+ *size += zone->kasan_redzone * 2;
+ }
+}
+
+/*
+ * Called from zalloc_internal() to fix up the address of the newly
+ * allocated element.
+ *
+ * Returns the element address skipping over the redzone on the left.
+ */
+static vm_offset_t
+kasan_fixup_allocated_element_address(
+ zone_t zone, /* the zone the element belongs to */
+ vm_offset_t addr) /* address of the element, including the redzone */
+{
+ /* Fixup the return address to skip the redzone */
+ if (zone->kasan_redzone) {
+ addr = kasan_alloc(addr, zone->elem_size,
+ zone->elem_size - 2 * zone->kasan_redzone, zone->kasan_redzone);
+ }
+ return addr;
+}
+
+/*
+ * Called from zfree() to add the element being freed to the KASan quarantine.
+ *
+ * Returns true if the newly-freed element made it into the quarantine without
+ * displacing another, false otherwise. In the latter case, addrp points to the
+ * address of the displaced element, which will be freed by the zone.
+ */
+static bool
+kasan_quarantine_freed_element(
+ zone_t *zonep, /* the zone the element is being freed to */
+ void **addrp) /* address of the element being freed */
+{
+ zone_t zone = *zonep;
+ void *addr = *addrp;
+
+ /*
+ * Resize back to the real allocation size and hand off to the KASan
+ * quarantine. `addr` may then point to a different allocation, if the
+ * current element replaced another in the quarantine. The zone then
+ * takes ownership of the swapped out free element.
+ */
+ vm_size_t usersz = zone->elem_size - 2 * zone->kasan_redzone;
+ vm_size_t sz = usersz;
+
+ if (addr && zone->kasan_redzone) {
+ kasan_check_free((vm_address_t)addr, usersz, KASAN_HEAP_ZALLOC);
+ addr = (void *)kasan_dealloc((vm_address_t)addr, &sz);
+ assert(sz == zone->elem_size);
+ }
+ if (addr && zone->kasan_quarantine) {
+ kasan_free(&addr, &sz, KASAN_HEAP_ZALLOC, zonep, usersz, true);
+ if (!addr) {
+ return TRUE;
+ }
+ }
+ *addrp = addr;
+ return FALSE;
+}
+
+#endif /* KASAN_ZALLOC */
+
+/*
+ * zinit initializes a new zone. The zone data structures themselves
+ * are stored in a zone, which is initially a static structure that
+ * is initialized by zone_init.
+ */
+
+zone_t
+zinit(
+ vm_size_t size, /* the size of an element */
+ vm_size_t max, /* maximum memory to use */
+ vm_size_t alloc, /* allocation size */
+ const char *name) /* a name for the zone */
+{
+ zone_t z;
+
+ size = compute_element_size(size);
+
+ simple_lock(&all_zones_lock, &zone_locks_grp);
+
+ assert(num_zones < MAX_ZONES);
+ assert(num_zones_in_use <= num_zones);
+
+ /* If possible, find a previously zdestroy'ed zone in the zone_array that we can reuse instead of initializing a new zone. */
+ for (int index = bitmap_first(zone_empty_bitmap, MAX_ZONES);
+ index >= 0 && index < (int)num_zones;
+ index = bitmap_next(zone_empty_bitmap, index)) {
+ z = &(zone_array[index]);
+
+ /*
+ * If the zone name and the element size are the same, we can just reuse the old zone struct.
+ * Otherwise hand out a new zone from the zone_array.
+ */
+ if (!strcmp(z->zone_name, name)) {
+ vm_size_t old_size = z->elem_size;
+#if KASAN_ZALLOC
+ old_size -= z->kasan_redzone * 2;
+#endif
+ if (old_size == size) {
+ /* Clear the empty bit for this zone, increment num_zones_in_use, and mark the zone as valid again. */
+ bitmap_clear(zone_empty_bitmap, index);
+ num_zones_in_use++;
+ z->zone_valid = TRUE;
+ z->zone_destruction = FALSE;
+
+ /* All other state is already set up since the zone was previously in use. Return early. */
+ simple_unlock(&all_zones_lock);
+ return z;
+ }
+ }
+ }
+
+ /* If we're here, it means we didn't find a zone above that we could simply reuse. Set up a new zone. */
+
+ /* Clear the empty bit for the new zone */
+ bitmap_clear(zone_empty_bitmap, num_zones);
+
+ z = &(zone_array[num_zones]);
+ z->index = num_zones;
+
+ num_zones++;
+ num_zones_in_use++;
+
+ /*
+ * Initialize the zone lock here before dropping the all_zones_lock. Otherwise we could race with
+ * zalloc_async() and try to grab the zone lock before it has been initialized, causing a panic.
+ */
+ lock_zone_init(z);
+
+ simple_unlock(&all_zones_lock);
+
+#if KASAN_ZALLOC
+ kasan_update_element_size_for_redzone(z, &size, &max, name);
+#endif
+
+ max = round_page(max);
+
+ vm_size_t best_alloc = PAGE_SIZE;
+
+ if ((size % PAGE_SIZE) == 0) {
+ /* zero fragmentation by definition */
+ best_alloc = size;
+ } else {
+ vm_size_t alloc_size;
+ for (alloc_size = (2 * PAGE_SIZE); alloc_size <= ZONE_MAX_ALLOC_SIZE; alloc_size += PAGE_SIZE) {
+ if (ZONE_ALLOC_FRAG_PERCENT(alloc_size, size) < ZONE_ALLOC_FRAG_PERCENT(best_alloc, size)) {
+ best_alloc = alloc_size;
+ }
+ }
+ }
+
+ alloc = best_alloc;
+ if (max && (max < alloc)) {
+ max = alloc;
+ }
+
+ z->free_elements = NULL;
+ queue_init(&z->pages.any_free_foreign);
+ queue_init(&z->pages.all_free);
+ queue_init(&z->pages.intermediate);
+ queue_init(&z->pages.all_used);
+ z->cur_size = 0;
+ z->page_count = 0;
+ z->max_size = max;
+ z->elem_size = size;
+ z->alloc_size = alloc;
+ z->count = 0;
+ z->countfree = 0;
+ z->count_all_free_pages = 0;
+ z->sum_count = 0LL;
+ z->doing_alloc_without_vm_priv = FALSE;
+ z->doing_alloc_with_vm_priv = FALSE;
+ z->exhaustible = FALSE;
+ z->collectable = TRUE;
+ z->allows_foreign = FALSE;
+ z->expandable = TRUE;
+ z->waiting = FALSE;
+ z->async_pending = FALSE;
+ z->caller_acct = TRUE;
+ z->noencrypt = FALSE;
+ z->no_callout = FALSE;
+ z->async_prio_refill = FALSE;
+ z->gzalloc_exempt = FALSE;
+ z->alignment_required = FALSE;
+ z->zone_replenishing = FALSE;
+ z->prio_refill_watermark = 0;
+ z->zone_replenish_thread = NULL;
+ z->zp_count = 0;
+ z->kasan_quarantine = TRUE;
+ z->zone_valid = TRUE;
+ z->zone_destruction = FALSE;
+ z->cpu_cache_enabled = FALSE;
+ z->clear_memory = FALSE;
+
+#if CONFIG_ZLEAKS
+ z->zleak_capture = 0;
+ z->zleak_on = FALSE;
+#endif /* CONFIG_ZLEAKS */
+
+ /*
+ * If the VM is ready to handle kmem_alloc requests, copy the zone name passed in.
+ *
+ * Else simply maintain a pointer to the name string. The only zones we'll actually have
+ * to do this for would be the VM-related zones that are created very early on before any
+ * kexts can be loaded (unloaded). So we should be fine with just a pointer in this case.
+ */
+ if (kmem_alloc_ready) {
+ size_t len = MIN(strlen(name) + 1, MACH_ZONE_NAME_MAX_LEN);
+
+ if (zone_names_start == 0 || ((zone_names_next - zone_names_start) + len) > PAGE_SIZE) {
+ printf("zalloc: allocating memory for zone names buffer\n");
+ kern_return_t retval = kmem_alloc_kobject(kernel_map, &zone_names_start,
+ PAGE_SIZE, VM_KERN_MEMORY_OSFMK);
+ if (retval != KERN_SUCCESS) {
+ panic("zalloc: zone_names memory allocation failed");
+ }
+ bzero((char *)zone_names_start, PAGE_SIZE);
+ zone_names_next = zone_names_start;
+ }
+
+ strlcpy((char *)zone_names_next, name, len);
+ z->zone_name = (char *)zone_names_next;
+ zone_names_next += len;
+ } else {
+ z->zone_name = name;
+ }
+
+ /*
+ * Check for and set up zone leak detection if requested via boot-args. We recognized two
+ * boot-args:
+ *
+ * zlog=<zone_to_log>
+ * zrecs=<num_records_in_log>
+ *
+ * The zlog arg is used to specify the zone name that should be logged, and zrecs is used to
+ * control the size of the log. If zrecs is not specified, a default value is used.
+ */
+
+ if (num_zones_logged < max_num_zones_to_log) {
+ int i = 1; /* zlog0 isn't allowed. */
+ boolean_t zone_logging_enabled = FALSE;
+ char zlog_name[MAX_ZONE_NAME] = ""; /* Temp. buffer to create the strings zlog1, zlog2 etc... */
+
+ while (i <= max_num_zones_to_log) {
+ snprintf(zlog_name, MAX_ZONE_NAME, "zlog%d", i);
+
+ if (PE_parse_boot_argn(zlog_name, zone_name_to_log, sizeof(zone_name_to_log)) == TRUE) {
+ if (track_this_zone(z->zone_name, zone_name_to_log)) {
+ if (z->zone_valid) {
+ z->zone_logging = TRUE;
+ zone_logging_enabled = TRUE;
+ num_zones_logged++;
+ break;
+ }
+ }
+ }
+ i++;
+ }
+
+ if (zone_logging_enabled == FALSE) {
+ /*
+ * Backwards compat. with the old boot-arg used to specify single zone logging i.e. zlog
+ * Needs to happen after the newer zlogn checks because the prefix will match all the zlogn
+ * boot-args.
+ */
+ if (PE_parse_boot_argn("zlog", zone_name_to_log, sizeof(zone_name_to_log)) == TRUE) {
+ if (track_this_zone(z->zone_name, zone_name_to_log)) {
+ if (z->zone_valid) {
+ z->zone_logging = TRUE;
+ zone_logging_enabled = TRUE;
+ num_zones_logged++;
+ }
+ }
+ }
+ }
+
+ if (log_records_init == FALSE && zone_logging_enabled == TRUE) {
+ if (PE_parse_boot_argn("zrecs", &log_records, sizeof(log_records)) == TRUE) {
+ /*
+ * Don't allow more than ZRECORDS_MAX records even if the user asked for more.
+ * This prevents accidentally hogging too much kernel memory and making the system
+ * unusable.
+ */
+
+ log_records = MIN(ZRECORDS_MAX, log_records);
+ log_records_init = TRUE;
+ } else {
+ log_records = ZRECORDS_DEFAULT;
+ log_records_init = TRUE;
+ }
+ }
+
+ /*
+ * If we want to log a zone, see if we need to allocate buffer space for the log. Some vm related zones are
+ * zinit'ed before we can do a kmem_alloc, so we have to defer allocation in that case. kmem_alloc_ready is set to
+ * TRUE once enough of the VM system is up and running to allow a kmem_alloc to work. If we want to log one
+ * of the VM related zones that's set up early on, we will skip allocation of the log until zinit is called again
+ * later on some other zone. So note we may be allocating a buffer to log a zone other than the one being initialized
+ * right now.
+ */
+ if (kmem_alloc_ready) {
+ zone_t curr_zone = NULL;
+ unsigned int max_zones = 0, zone_idx = 0;
+
+ simple_lock(&all_zones_lock, &zone_locks_grp);
+ max_zones = num_zones;
+ simple_unlock(&all_zones_lock);
+
+ for (zone_idx = 0; zone_idx < max_zones; zone_idx++) {
+ curr_zone = &(zone_array[zone_idx]);
+
+ if (!curr_zone->zone_valid) {
+ continue;
+ }
+
+ /*
+ * We work with the zone unlocked here because we could end up needing the zone lock to
+ * enable logging for this zone e.g. need a VM object to allocate memory to enable logging for the
+ * VM objects zone.
+ *
+ * We don't expect these zones to be needed at this early a time in boot and so take this chance.
+ */
+ if (curr_zone->zone_logging && curr_zone->zlog_btlog == NULL) {
+ curr_zone->zlog_btlog = btlog_create(log_records, MAX_ZTRACE_DEPTH, (corruption_debug_flag == FALSE) /* caller_will_remove_entries_for_element? */);
+
+ if (curr_zone->zlog_btlog) {
+ printf("zone: logging started for zone %s\n", curr_zone->zone_name);
+ } else {
+ printf("zone: couldn't allocate memory for zrecords, turning off zleak logging\n");
+ curr_zone->zone_logging = FALSE;
+ }
+ }
+ }
+ }
+ }
+
+#if CONFIG_GZALLOC
+ gzalloc_zone_init(z);
+#endif
+
+#if CONFIG_ZCACHE
+ /* Check if boot-arg specified it should have a cache */
+ if (cache_all_zones || track_this_zone(name, cache_zone_name)) {
+ zone_change(z, Z_CACHING_ENABLED, TRUE);
+ }
+#endif
+
+ return z;
+}
+unsigned zone_replenish_loops, zone_replenish_wakeups, zone_replenish_wakeups_initiated, zone_replenish_throttle_count;
+
+static void zone_replenish_thread(zone_t);
+
+/* High priority VM privileged thread used to asynchronously refill a designated
+ * zone, such as the reserved VM map entry zone.
+ */
+__dead2
+static void
+zone_replenish_thread(zone_t z)
+{
+ vm_size_t free_size;
+ current_thread()->options |= TH_OPT_VMPRIV;
+
+ for (;;) {
+ lock_zone(z);
+ assert(z->zone_valid);
+ z->zone_replenishing = TRUE;
+ assert(z->prio_refill_watermark != 0);
+ while ((free_size = (z->cur_size - (z->count * z->elem_size))) < (z->prio_refill_watermark * z->elem_size)) {
+ assert(z->doing_alloc_without_vm_priv == FALSE);
+ assert(z->doing_alloc_with_vm_priv == FALSE);
+ assert(z->async_prio_refill == TRUE);
+
+ unlock_zone(z);
+ int zflags = KMA_KOBJECT | KMA_NOPAGEWAIT;
+ vm_offset_t space, alloc_size;
+ kern_return_t kr;
+
+ if (vm_pool_low()) {
+ alloc_size = round_page(z->elem_size);
+ } else {
+ alloc_size = z->alloc_size;
+ }
+
+ if (z->noencrypt) {
+ zflags |= KMA_NOENCRYPT;
+ }
+
+ if (z->clear_memory) {
+ zflags |= KMA_ZERO;
+ }
+
+ /* Trigger jetsams via the vm_pageout_garbage_collect thread if we're running out of zone memory */
+ if (is_zone_map_nearing_exhaustion()) {
+ thread_wakeup((event_t) &vm_pageout_garbage_collect);
+ }
+
+ kr = kernel_memory_allocate(zone_map, &space, alloc_size, 0, zflags, VM_KERN_MEMORY_ZONE);
+
+ if (kr == KERN_SUCCESS) {
+ zcram(z, space, alloc_size);
+ } else if (kr == KERN_RESOURCE_SHORTAGE) {
+ VM_PAGE_WAIT();
+ } else if (kr == KERN_NO_SPACE) {
+ kr = kernel_memory_allocate(kernel_map, &space, alloc_size, 0, zflags, VM_KERN_MEMORY_ZONE);
+ if (kr == KERN_SUCCESS) {
+ zcram(z, space, alloc_size);
+ } else {
+ assert_wait_timeout(&z->zone_replenish_thread, THREAD_UNINT, 1, 100 * NSEC_PER_USEC);
+ thread_block(THREAD_CONTINUE_NULL);
+ }
+ }
+
+ lock_zone(z);
+ assert(z->zone_valid);
+ zone_replenish_loops++;
+ }
+
+ z->zone_replenishing = FALSE;
+ /* Signal any potential throttled consumers, terminating
+ * their timer-bounded waits.
+ */
+ thread_wakeup(z);
+
+ assert_wait(&z->zone_replenish_thread, THREAD_UNINT);
+ unlock_zone(z);
+ thread_block(THREAD_CONTINUE_NULL);
+ zone_replenish_wakeups++;
+ }
+}
+
+void
+zone_prio_refill_configure(zone_t z, vm_size_t low_water_mark)
+{
+ z->prio_refill_watermark = low_water_mark;
+
+ z->async_prio_refill = TRUE;
+ OSMemoryBarrier();
+ kern_return_t tres = kernel_thread_start_priority((thread_continue_t)zone_replenish_thread, z, MAXPRI_KERNEL, &z->zone_replenish_thread);
+
+ if (tres != KERN_SUCCESS) {
+ panic("zone_prio_refill_configure, thread create: 0x%x", tres);
+ }
+
+ thread_deallocate(z->zone_replenish_thread);
+}
+
+void
+zdestroy(zone_t z)
+{
+ unsigned int zindex;
+
+ assert(z != NULL);
+
+ lock_zone(z);
+ assert(z->zone_valid);
+
+ /* Assert that the zone does not have any allocations in flight */
+ assert(z->doing_alloc_without_vm_priv == FALSE);
+ assert(z->doing_alloc_with_vm_priv == FALSE);
+ assert(z->async_pending == FALSE);
+ assert(z->waiting == FALSE);
+ assert(z->async_prio_refill == FALSE);
+
+#if !KASAN_ZALLOC
+ /*
+ * Unset the valid bit. We'll hit an assert failure on further operations on this zone, until zinit() is called again.
+ * Leave the zone valid for KASan as we will see zfree's on quarantined free elements even after the zone is destroyed.
+ */
+ z->zone_valid = FALSE;
+#endif
+ z->zone_destruction = TRUE;
+ unlock_zone(z);
+
+#if CONFIG_ZCACHE
+ /* Drain the per-cpu caches if caching is enabled for the zone. */
+ if (zone_caching_enabled(z)) {
+ panic("zdestroy: Zone caching enabled for zone %s", z->zone_name);
+ }
+#endif /* CONFIG_ZCACHE */
+
+ /* Dump all the free elements */
+ drop_free_elements(z);
+
+#if CONFIG_GZALLOC
+ /* If the zone is gzalloc managed dump all the elements in the free cache */
+ gzalloc_empty_free_cache(z);
+#endif
+
+ lock_zone(z);
+
+#if !KASAN_ZALLOC
+ /* Assert that all counts are zero */
+ assert(z->count == 0);
+ assert(z->countfree == 0);
+ assert(z->cur_size == 0);
+ assert(z->page_count == 0);
+ assert(z->count_all_free_pages == 0);
+
+ /* Assert that all queues except the foreign queue are empty. The zone allocator doesn't know how to free up foreign memory. */
+ assert(queue_empty(&z->pages.all_used));
+ assert(queue_empty(&z->pages.intermediate));
+ assert(queue_empty(&z->pages.all_free));
+#endif
+
+ zindex = z->index;
+
+ unlock_zone(z);
+
+ simple_lock(&all_zones_lock, &zone_locks_grp);
+
+ assert(!bitmap_test(zone_empty_bitmap, zindex));
+ /* Mark the zone as empty in the bitmap */
+ bitmap_set(zone_empty_bitmap, zindex);
+ num_zones_in_use--;
+ assert(num_zones_in_use > 0);
+
+ simple_unlock(&all_zones_lock);
+}
+
+/* Initialize the metadata for an allocation chunk */
+static inline void
+zcram_metadata_init(vm_offset_t newmem, vm_size_t size, struct zone_page_metadata *chunk_metadata)
+{
+ struct zone_page_metadata *page_metadata;
+
+ /* The first page is the real metadata for this allocation chunk. We mark the others as fake metadata */
+ size -= PAGE_SIZE;
+ newmem += PAGE_SIZE;
+
+ for (; size > 0; newmem += PAGE_SIZE, size -= PAGE_SIZE) {
+ page_metadata = get_zone_page_metadata((struct zone_free_element *)newmem, TRUE);
+ assert(page_metadata != chunk_metadata);
+ PAGE_METADATA_SET_ZINDEX(page_metadata, MULTIPAGE_METADATA_MAGIC);
+ page_metadata_set_realmeta(page_metadata, chunk_metadata);
+ page_metadata->free_count = 0;
+ }
+ return;
+}
+
+
+static void
+random_free_to_zone(
+ zone_t zone,
+ vm_offset_t newmem,
+ vm_offset_t first_element_offset,
+ int element_count,
+ unsigned int *entropy_buffer)
+{
+ vm_offset_t last_element_offset;
+ vm_offset_t element_addr;
+ vm_size_t elem_size;
+ int index;
+
+ assert(element_count && element_count <= ZONE_CHUNK_MAXELEMENTS);
+ elem_size = zone->elem_size;
+ last_element_offset = first_element_offset + ((element_count * elem_size) - elem_size);
+ for (index = 0; index < element_count; index++) {
+ assert(first_element_offset <= last_element_offset);
+ if (
+#if DEBUG || DEVELOPMENT
+ leak_scan_debug_flag || __improbable(zone->tags) ||
+#endif /* DEBUG || DEVELOPMENT */
+ random_bool_gen_bits(&zone_bool_gen, entropy_buffer, MAX_ENTROPY_PER_ZCRAM, 1)) {
+ element_addr = newmem + first_element_offset;
+ first_element_offset += elem_size;
+ } else {
+ element_addr = newmem + last_element_offset;
+ last_element_offset -= elem_size;
+ }
+ if (element_addr != (vm_offset_t)zone) {
+ zone->count++; /* compensate for free_to_zone */
+ free_to_zone(zone, element_addr, FALSE);
+ }
+ zone->cur_size += elem_size;
+ }
+}
+
+/*
+ * Cram the given memory into the specified zone. Update the zone page count accordingly.
+ */
+void
+zcram(
+ zone_t zone,
+ vm_offset_t newmem,
+ vm_size_t size)
+{
+ vm_size_t elem_size;
+ boolean_t from_zm = FALSE;
+ int element_count;
+ unsigned int entropy_buffer[MAX_ENTROPY_PER_ZCRAM] = { 0 };
+
+ /* Basic sanity checks */
+ assert(zone != ZONE_NULL && newmem != (vm_offset_t)0);
+ assert(!zone->collectable || zone->allows_foreign
+ || (from_zone_map(newmem, size)));
+
+ elem_size = zone->elem_size;
+
+ KDBG(MACHDBG_CODE(DBG_MACH_ZALLOC, ZALLOC_ZCRAM) | DBG_FUNC_START, zone->index, size);
+
+ if (from_zone_map(newmem, size)) {
+ from_zm = TRUE;
+ }
+
+ if (!from_zm) {
+ /* We cannot support elements larger than page size for foreign memory because we
+ * put metadata on the page itself for each page of foreign memory. We need to do
+ * this in order to be able to reach the metadata when any element is freed
+ */
+ assert((zone->allows_foreign == TRUE) && (zone->elem_size <= (PAGE_SIZE - sizeof(struct zone_page_metadata))));
+ }
+
+#if DEBUG || DEVELOPMENT
+ if (zalloc_debug & ZALLOC_DEBUG_ZCRAM) {
+ kprintf("zcram(%p[%s], 0x%lx%s, 0x%lx)\n", zone, zone->zone_name,
+ (unsigned long)newmem, from_zm ? "" : "[F]", (unsigned long)size);
+ }
+#endif /* DEBUG || DEVELOPMENT */
+
+ ZONE_PAGE_COUNT_INCR(zone, (size / PAGE_SIZE));
+
+ /*
+ * Initialize the metadata for all pages. We dont need the zone lock
+ * here because we are not manipulating any zone related state yet.
+ */
+
+ struct zone_page_metadata *chunk_metadata;
+ size_t zone_page_metadata_size = sizeof(struct zone_page_metadata);
+
+ assert((newmem & PAGE_MASK) == 0);
+ assert((size & PAGE_MASK) == 0);
+
+ chunk_metadata = get_zone_page_metadata((struct zone_free_element *)newmem, TRUE);
+ chunk_metadata->pages.next = NULL;
+ chunk_metadata->pages.prev = NULL;
+ page_metadata_set_freelist(chunk_metadata, 0);
+ PAGE_METADATA_SET_ZINDEX(chunk_metadata, zone->index);
+ chunk_metadata->free_count = 0;
+ assert((size / PAGE_SIZE) <= ZONE_CHUNK_MAXPAGES);
+ chunk_metadata->page_count = (unsigned)(size / PAGE_SIZE);
+
+ zcram_metadata_init(newmem, size, chunk_metadata);
+
+#if VM_MAX_TAG_ZONES
+ if (__improbable(zone->tags)) {
+ assert(from_zm);
+ ztMemoryAdd(zone, newmem, size);
+ }
+#endif /* VM_MAX_TAG_ZONES */
+
+ lock_zone(zone);
+ assert(zone->zone_valid);
+ enqueue_tail(&zone->pages.all_used, &(chunk_metadata->pages));
+
+ if (!from_zm) {
+ /* We cannot support elements larger than page size for foreign memory because we
+ * put metadata on the page itself for each page of foreign memory. We need to do
+ * this in order to be able to reach the metadata when any element is freed
+ */
+
+ for (; size > 0; newmem += PAGE_SIZE, size -= PAGE_SIZE) {
+ vm_offset_t first_element_offset = 0;
+ if (zone_page_metadata_size % ZONE_ELEMENT_ALIGNMENT == 0) {
+ first_element_offset = zone_page_metadata_size;
+ } else {
+ first_element_offset = zone_page_metadata_size + (ZONE_ELEMENT_ALIGNMENT - (zone_page_metadata_size % ZONE_ELEMENT_ALIGNMENT));
+ }
+ element_count = (unsigned int)((PAGE_SIZE - first_element_offset) / elem_size);
+ random_free_to_zone(zone, newmem, first_element_offset, element_count, entropy_buffer);
+ }
+ } else {
+ element_count = (unsigned int)(size / elem_size);
+ random_free_to_zone(zone, newmem, 0, element_count, entropy_buffer);
+ }
+ unlock_zone(zone);
+
+ KDBG(MACHDBG_CODE(DBG_MACH_ZALLOC, ZALLOC_ZCRAM) | DBG_FUNC_END, zone->index);
+}
+
+/*
+ * Fill a zone with enough memory to contain at least nelem elements.
+ * Return the number of elements actually put into the zone, which may
+ * be more than the caller asked for since the memory allocation is
+ * rounded up to the next zone allocation size.
+ */
+int
+zfill(
+ zone_t zone,
+ int nelem)
+{
+ kern_return_t kr;
+ vm_offset_t memory;
+
+ vm_size_t alloc_size = zone->alloc_size;
+ vm_size_t elem_per_alloc = alloc_size / zone->elem_size;
+ vm_size_t nalloc = (nelem + elem_per_alloc - 1) / elem_per_alloc;
+ int zflags = KMA_KOBJECT;
+
+ if (zone->clear_memory) {
+ zflags |= KMA_ZERO;
+ }
+
+ /* Don't mix-and-match zfill with foreign memory */
+ assert(!zone->allows_foreign);
+
+ /* Trigger jetsams via the vm_pageout_garbage_collect thread if we're running out of zone memory */
+ if (is_zone_map_nearing_exhaustion()) {
+ thread_wakeup((event_t) &vm_pageout_garbage_collect);
+ }
+
+ kr = kernel_memory_allocate(zone_map, &memory, nalloc * alloc_size, 0, zflags, VM_KERN_MEMORY_ZONE);
+ if (kr != KERN_SUCCESS) {
+ printf("%s: kernel_memory_allocate() of %lu bytes failed\n",
+ __func__, (unsigned long)(nalloc * alloc_size));
+ return 0;
+ }
+
+ for (vm_size_t i = 0; i < nalloc; i++) {
+ zcram(zone, memory + i * alloc_size, alloc_size);
+ }
+
+ return (int)(nalloc * elem_per_alloc);
+}
+
+/*
+ * Initialize the "zone of zones" which uses fixed memory allocated
+ * earlier in memory initialization. zone_bootstrap is called
+ * before zone_init.
+ */
+void
+zone_bootstrap(void)
+{
+ char temp_buf[16];
+
+#if DEBUG || DEVELOPMENT
+ if (!PE_parse_boot_argn("zalloc_debug", &zalloc_debug, sizeof(zalloc_debug))) {
+ zalloc_debug = 0;
+ }
+#endif /* DEBUG || DEVELOPMENT */
+
+ /* Set up zone element poisoning */
+ zp_init();
+
+ random_bool_init(&zone_bool_gen);
+
+ /* should zlog log to debug zone corruption instead of leaks? */
+ if (PE_parse_boot_argn("-zc", temp_buf, sizeof(temp_buf))) {
+ corruption_debug_flag = TRUE;
+ }
+
+#if DEBUG || DEVELOPMENT
+ /* should perform zone element size checking in copyin/copyout? */
+ if (PE_parse_boot_argn("-no-copyio-zalloc-check", temp_buf, sizeof(temp_buf))) {
+ copyio_zalloc_check = FALSE;
+ }
+#if VM_MAX_TAG_ZONES
+ /* enable tags for zones that ask for */
+ if (PE_parse_boot_argn("-zt", temp_buf, sizeof(temp_buf))) {
+ zone_tagging_on = TRUE;
+ }
+#endif /* VM_MAX_TAG_ZONES */
+ /* disable element location randomization in a page */
+ if (PE_parse_boot_argn("-zl", temp_buf, sizeof(temp_buf))) {
+ leak_scan_debug_flag = TRUE;
+ }
+#endif
+
+ simple_lock_init(&all_zones_lock, 0);
+
+ num_zones_in_use = 0;
+ num_zones = 0;
+ /* Mark all zones as empty */
+ bitmap_full(zone_empty_bitmap, BITMAP_LEN(MAX_ZONES));
+ zone_names_next = zone_names_start = 0;
+
+#if DEBUG || DEVELOPMENT
+ simple_lock_init(&zone_test_lock, 0);
+#endif /* DEBUG || DEVELOPMENT */
+
+ thread_call_setup(&call_async_alloc, zalloc_async, NULL);
+
+ /* initializing global lock group for zones */
+ lck_grp_attr_setdefault(&zone_locks_grp_attr);
+ lck_grp_init(&zone_locks_grp, "zone_locks", &zone_locks_grp_attr);
+
+ lck_attr_setdefault(&zone_metadata_lock_attr);
+ lck_mtx_init_ext(&zone_metadata_region_lck, &zone_metadata_region_lck_ext, &zone_locks_grp, &zone_metadata_lock_attr);
+
+#if CONFIG_ZCACHE
+ /* zcc_enable_for_zone_name=<zone>: enable per-cpu zone caching for <zone>. */
+ if (PE_parse_boot_arg_str("zcc_enable_for_zone_name", cache_zone_name, sizeof(cache_zone_name))) {
+ printf("zcache: caching enabled for zone %s\n", cache_zone_name);
+ }
+
+ /* -zcache_all: enable per-cpu zone caching for all zones, overrides 'zcc_enable_for_zone_name'. */
+ if (PE_parse_boot_argn("-zcache_all", temp_buf, sizeof(temp_buf))) {
+ cache_all_zones = TRUE;
+ printf("zcache: caching enabled for all zones\n");
+ }
+#endif /* CONFIG_ZCACHE */
+}
+
+/*
+ * We're being very conservative here and picking a value of 95%. We might need to lower this if
+ * we find that we're not catching the problem and are still hitting zone map exhaustion panics.
+ */
+#define ZONE_MAP_JETSAM_LIMIT_DEFAULT 95
+
+/*
+ * Trigger zone-map-exhaustion jetsams if the zone map is X% full, where X=zone_map_jetsam_limit.
+ * Can be set via boot-arg "zone_map_jetsam_limit". Set to 95% by default.
+ */
+unsigned int zone_map_jetsam_limit = ZONE_MAP_JETSAM_LIMIT_DEFAULT;
+
+/*
+ * Returns pid of the task with the largest number of VM map entries.
+ */
+extern pid_t find_largest_process_vm_map_entries(void);
+
+/*
+ * Callout to jetsam. If pid is -1, we wake up the memorystatus thread to do asynchronous kills.
+ * For any other pid we try to kill that process synchronously.
+ */
+boolean_t memorystatus_kill_on_zone_map_exhaustion(pid_t pid);
+
+void
+get_zone_map_size(uint64_t *current_size, uint64_t *capacity)
+{
+ *current_size = zone_map->size;
+ *capacity = vm_map_max(zone_map) - vm_map_min(zone_map);
+}
+
+void
+get_largest_zone_info(char *zone_name, size_t zone_name_len, uint64_t *zone_size)
+{
+ zone_t largest_zone = zone_find_largest();
+ strlcpy(zone_name, largest_zone->zone_name, zone_name_len);
+ *zone_size = largest_zone->cur_size;
+}
+
+boolean_t
+is_zone_map_nearing_exhaustion(void)
+{
+ uint64_t size = zone_map->size;
+ uint64_t capacity = vm_map_max(zone_map) - vm_map_min(zone_map);
+ if (size > ((capacity * zone_map_jetsam_limit) / 100)) {
+ return TRUE;
+ }
+ return FALSE;
+}
+
+extern zone_t vm_map_entry_zone;
+extern zone_t vm_object_zone;
+
+#define VMENTRY_TO_VMOBJECT_COMPARISON_RATIO 98
+
+/*
+ * Tries to kill a single process if it can attribute one to the largest zone. If not, wakes up the memorystatus thread
+ * to walk through the jetsam priority bands and kill processes.
+ */
+static void
+kill_process_in_largest_zone(void)
+{
+ pid_t pid = -1;
+ zone_t largest_zone = zone_find_largest();
+
+ printf("zone_map_exhaustion: Zone map size %lld, capacity %lld [jetsam limit %d%%]\n", (uint64_t)zone_map->size,
+ (uint64_t)(vm_map_max(zone_map) - vm_map_min(zone_map)), zone_map_jetsam_limit);
+ printf("zone_map_exhaustion: Largest zone %s, size %lu\n", largest_zone->zone_name, (uintptr_t)largest_zone->cur_size);
+
+ /*
+ * We want to make sure we don't call this function from userspace. Or we could end up trying to synchronously kill the process
+ * whose context we're in, causing the system to hang.
+ */
+ assert(current_task() == kernel_task);
+
+ /*
+ * If vm_object_zone is the largest, check to see if the number of elements in vm_map_entry_zone is comparable. If so, consider
+ * vm_map_entry_zone as the largest. This lets us target a specific process to jetsam to quickly recover from the zone map bloat.
+ */
+ if (largest_zone == vm_object_zone) {
+ unsigned int vm_object_zone_count = vm_object_zone->count;
+ unsigned int vm_map_entry_zone_count = vm_map_entry_zone->count;
+ /* Is the VM map entries zone count >= 98% of the VM objects zone count? */
+ if (vm_map_entry_zone_count >= ((vm_object_zone_count * VMENTRY_TO_VMOBJECT_COMPARISON_RATIO) / 100)) {
+ largest_zone = vm_map_entry_zone;
+ printf("zone_map_exhaustion: Picking VM map entries as the zone to target, size %lu\n", (uintptr_t)largest_zone->cur_size);
+ }
+ }
+
+ /* TODO: Extend this to check for the largest process in other zones as well. */
+ if (largest_zone == vm_map_entry_zone) {
+ pid = find_largest_process_vm_map_entries();
+ } else {
+ printf("zone_map_exhaustion: Nothing to do for the largest zone [%s]. Waking up memorystatus thread.\n", largest_zone->zone_name);
+ }
+ if (!memorystatus_kill_on_zone_map_exhaustion(pid)) {
+ printf("zone_map_exhaustion: Call to memorystatus failed, victim pid: %d\n", pid);
+ }
+}
+
+/* Global initialization of Zone Allocator.
+ * Runs after zone_bootstrap.
+ */
+void
+zone_init(
+ vm_size_t max_zonemap_size)
+{
+ kern_return_t retval;
+ vm_offset_t zone_min;
+ vm_offset_t zone_max;
+ vm_offset_t zone_metadata_space;
+ unsigned int zone_pages;
+ vm_map_kernel_flags_t vmk_flags;
+
+#if VM_MAX_TAG_ZONES
+ if (zone_tagging_on) {
+ ztInit(max_zonemap_size, &zone_locks_grp);
+ }
+#endif
+
+ vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+ vmk_flags.vmkf_permanent = TRUE;
+ retval = kmem_suballoc(kernel_map, &zone_min, max_zonemap_size,
+ FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_ZONE,
+ &zone_map);
+
+ if (retval != KERN_SUCCESS) {
+ panic("zone_init: kmem_suballoc failed");
+ }
+ zone_max = zone_min + round_page(max_zonemap_size);
+
+#if CONFIG_GZALLOC
+ gzalloc_init(max_zonemap_size);
+#endif
+
+ /*
+ * Setup garbage collection information:
+ */
+ zone_map_min_address = zone_min;
+ zone_map_max_address = zone_max;
+
+ zone_pages = (unsigned int)atop_kernel(zone_max - zone_min);
+ zone_metadata_space = round_page(zone_pages * sizeof(struct zone_page_metadata));
+ retval = kernel_memory_allocate(zone_map, &zone_metadata_region_min, zone_metadata_space,
+ 0, KMA_KOBJECT | KMA_VAONLY | KMA_PERMANENT, VM_KERN_MEMORY_OSFMK);
+ if (retval != KERN_SUCCESS) {
+ panic("zone_init: zone_metadata_region initialization failed!");
+ }
+ zone_metadata_region_max = zone_metadata_region_min + zone_metadata_space;
+
+#if defined(__LP64__)
+ /*
+ * ensure that any vm_page_t that gets created from
+ * the vm_page zone can be packed properly (see vm_page.h
+ * for the packing requirements
+ */
+ if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_metadata_region_max))) != (vm_page_t)zone_metadata_region_max) {
+ panic("VM_PAGE_PACK_PTR failed on zone_metadata_region_max - %p", (void *)zone_metadata_region_max);
+ }
+
+ if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_map_max_address))) != (vm_page_t)zone_map_max_address) {
+ panic("VM_PAGE_PACK_PTR failed on zone_map_max_address - %p", (void *)zone_map_max_address);
+ }
+#endif
+
+ lck_grp_attr_setdefault(&zone_gc_lck_grp_attr);
+ lck_grp_init(&zone_gc_lck_grp, "zone_gc", &zone_gc_lck_grp_attr);
+ lck_attr_setdefault(&zone_gc_lck_attr);
+ lck_mtx_init_ext(&zone_gc_lock, &zone_gc_lck_ext, &zone_gc_lck_grp, &zone_gc_lck_attr);
+
+#if CONFIG_ZLEAKS
+ /*
+ * Initialize the zone leak monitor
+ */
+ zleak_init(max_zonemap_size);
+#endif /* CONFIG_ZLEAKS */
+
+#if VM_MAX_TAG_ZONES
+ if (zone_tagging_on) {
+ vm_allocation_zones_init();
+ }
+#endif
+
+ int jetsam_limit_temp = 0;
+ if (PE_parse_boot_argn("zone_map_jetsam_limit", &jetsam_limit_temp, sizeof(jetsam_limit_temp)) &&
+ jetsam_limit_temp > 0 && jetsam_limit_temp <= 100) {
+ zone_map_jetsam_limit = jetsam_limit_temp;
+ }
+}
+
+#pragma mark -
+#pragma mark zalloc_canblock
+
+extern boolean_t early_boot_complete;
+
+void
+zalloc_poison_element(boolean_t check_poison, zone_t zone, vm_offset_t addr)
+{
+ vm_offset_t inner_size = zone->elem_size;
+ if (__improbable(check_poison && addr)) {
+ vm_offset_t *element_cursor = ((vm_offset_t *) addr) + 1;
+ vm_offset_t *backup = get_backup_ptr(inner_size, (vm_offset_t *) addr);
+
+ for (; element_cursor < backup; element_cursor++) {
+ if (__improbable(*element_cursor != ZP_POISON)) {
+ zone_element_was_modified_panic(zone,
+ addr,
+ *element_cursor,
+ ZP_POISON,
+ ((vm_offset_t)element_cursor) - addr);
+ }
+ }
+ }
+
+ if (addr) {
+ /*
+ * Clear out the old next pointer and backup to avoid leaking the cookie
+ * and so that only values on the freelist have a valid cookie
+ */
+
+ vm_offset_t *primary = (vm_offset_t *) addr;
+ vm_offset_t *backup = get_backup_ptr(inner_size, primary);
+
+ *primary = ZP_POISON;
+ *backup = ZP_POISON;
+ }
+}
+
+/*
+ * When deleting page mappings from the kernel map, it might be necessary to split
+ * apart an existing vm_map_entry. That means that a "free" operation, will need to
+ * *allocate* new vm_map_entry structures before it can free a page.
+ *
+ * This reserve here is the number of elements which are held back from everyone except
+ * the zone_gc thread. This is done so the zone_gc thread should never have to wait for
+ * the zone replenish thread for vm_map_entry structs. If it did, it could wind up
+ * in a deadlock.
+ */
+#define VM_MAP_ENTRY_RESERVE_CNT 8
+
+/*
+ * zalloc returns an element from the specified zone.
+ */
+static void *
+zalloc_internal(
+ zone_t zone,
+ boolean_t canblock,
+ boolean_t nopagewait,
+ vm_size_t
+#if !VM_MAX_TAG_ZONES
+ __unused
+#endif
+ reqsize,
+ vm_tag_t tag)
+{
+ vm_offset_t addr = 0;
+ kern_return_t retval;
+ uintptr_t zbt[MAX_ZTRACE_DEPTH]; /* used in zone leak logging and zone leak detection */
+ unsigned int numsaved = 0;
+ thread_t thr = current_thread();
+ boolean_t check_poison = FALSE;
+ boolean_t set_doing_alloc_with_vm_priv = FALSE;
+
+#if CONFIG_ZLEAKS
+ uint32_t zleak_tracedepth = 0; /* log this allocation if nonzero */
+#endif /* CONFIG_ZLEAKS */
+
+#if KASAN
+ /*
+ * KASan uses zalloc() for fakestack, which can be called anywhere. However,
+ * we make sure these calls can never block.
+ */
+ boolean_t irq_safe = FALSE;
+ const char *fakestack_name = "fakestack.";
+ if (strncmp(zone->zone_name, fakestack_name, strlen(fakestack_name)) == 0) {
+ irq_safe = TRUE;
+ }
+#elif MACH_ASSERT
+ /* In every other case, zalloc() from interrupt context is unsafe. */
+ const boolean_t irq_safe = FALSE;
+#endif
+
+ assert(zone != ZONE_NULL);
+ assert(irq_safe || ml_get_interrupts_enabled() || ml_is_quiescing() || debug_mode_active() || !early_boot_complete);
+
+#if CONFIG_GZALLOC
+ addr = gzalloc_alloc(zone, canblock);
+#endif
+ /*
+ * If zone logging is turned on and this is the zone we're tracking, grab a backtrace.
+ */
+ if (__improbable(DO_LOGGING(zone))) {
+ numsaved = OSBacktrace((void*) zbt, MAX_ZTRACE_DEPTH);
+ }
+
+#if CONFIG_ZLEAKS
+ /*
+ * Zone leak detection: capture a backtrace every zleak_sample_factor
+ * allocations in this zone.
+ */
+ if (__improbable(zone->zleak_on && sample_counter(&zone->zleak_capture, zleak_sample_factor) == TRUE)) {
+ /* Avoid backtracing twice if zone logging is on */
+ if (numsaved == 0) {
+ zleak_tracedepth = backtrace(zbt, MAX_ZTRACE_DEPTH, NULL);
+ } else {
+ zleak_tracedepth = numsaved;
+ }
+ }
+#endif /* CONFIG_ZLEAKS */
+
+#if VM_MAX_TAG_ZONES
+ if (__improbable(zone->tags)) {
+ vm_tag_will_update_zone(tag, zone->tag_zone_index);
+ }
+#endif /* VM_MAX_TAG_ZONES */
+
+#if CONFIG_ZCACHE
+ if (__probable(addr == 0)) {
+ if (zone_caching_enabled(zone)) {
+ addr = zcache_alloc_from_cpu_cache(zone);
+ if (addr) {
+#if KASAN_ZALLOC
+ addr = kasan_fixup_allocated_element_address(zone, addr);
+#endif
+ if (__improbable(DO_LOGGING(zone) && addr)) {
+ btlog_add_entry(zone->zlog_btlog, (void *)addr,
+ ZOP_ALLOC, (void **)zbt, numsaved);
+ }
+ DTRACE_VM2(zalloc, zone_t, zone, void*, addr);
+ return (void *)addr;
+ }
+ }
+ }
+#endif /* CONFIG_ZCACHE */
+
+ lock_zone(zone);
+ assert(zone->zone_valid);
+
+ /*
+ * Check if we need another thread to replenish the zone.
+ * This is used for elements, like vm_map_entry, which are
+ * needed themselves to implement zalloc().
+ */
+ if (zone->async_prio_refill && zone->zone_replenish_thread) {
+ vm_size_t curr_free;
+ vm_size_t refill_level;
+ const vm_size_t reserved_min = VM_MAP_ENTRY_RESERVE_CNT * zone->elem_size;
+
+ for (;;) {
+ curr_free = (zone->cur_size - (zone->count * zone->elem_size));
+ refill_level = zone->prio_refill_watermark * zone->elem_size;
+
+ /*
+ * Nothing to do if there are plenty of elements.
+ */
+ if (curr_free > refill_level) {
+ break;
+ }
+
+ /*
+ * Wakeup the replenish thread.
+ */
+ zone_replenish_wakeups_initiated++;
+ thread_wakeup(&zone->zone_replenish_thread);
+
+ /*
+ * If we:
+ * - still have head room, more than half the refill amount, or
+ * - this is a VMPRIV thread and we're still above reserved, or
+ * - this is the zone garbage collection thread which may use the reserve
+ * then we don't have to wait for the replenish thread.
+ *
+ * The reserve for the garbage collection thread is to avoid a deadlock
+ * on the zone_map_lock between the replenish thread and GC thread.
+ */
+ if (curr_free > refill_level / 2 ||
+ ((thr->options & TH_OPT_VMPRIV) && curr_free > reserved_min) ||
+ (thr->options & TH_OPT_ZONE_GC)) {
+ break;
+ }
+ zone_replenish_throttle_count++;
+ unlock_zone(zone);
+ assert_wait_timeout(zone, THREAD_UNINT, 1, NSEC_PER_MSEC);
+ thread_block(THREAD_CONTINUE_NULL);
+ lock_zone(zone);
+
+ assert(zone->zone_valid);
+ }
+ }
+
+ if (__probable(addr == 0)) {
+ addr = try_alloc_from_zone(zone, tag, &check_poison);
+ }
+
+ /* If we're here because of zone_gc(), we didn't wait for zone_replenish_thread to finish.
+ * So we need to ensure that we did successfully grab an element. And we only need to assert
+ * this for zones that have a replenish thread configured (in this case, the Reserved VM map
+ * entries zone). The value of reserved_min in the previous bit of code should have given us
+ * headroom even though the GC thread didn't wait.
+ */
+ if ((thr->options & TH_OPT_ZONE_GC) && zone->async_prio_refill) {
+ assert(addr != 0);
+ }
+
+ while ((addr == 0) && canblock) {
+ /*
+ * zone is empty, try to expand it
+ *
+ * Note that we now allow up to 2 threads (1 vm_privliged and 1 non-vm_privliged)
+ * to expand the zone concurrently... this is necessary to avoid stalling
+ * vm_privileged threads running critical code necessary to continue compressing/swapping
+ * pages (i.e. making new free pages) from stalling behind non-vm_privileged threads
+ * waiting to acquire free pages when the vm_page_free_count is below the
+ * vm_page_free_reserved limit.
+ */
+ if ((zone->doing_alloc_without_vm_priv || zone->doing_alloc_with_vm_priv) &&
+ (((thr->options & TH_OPT_VMPRIV) == 0) || zone->doing_alloc_with_vm_priv)) {
+ /*
+ * This is a non-vm_privileged thread and a non-vm_privileged or
+ * a vm_privileged thread is already expanding the zone...
+ * OR
+ * this is a vm_privileged thread and a vm_privileged thread is
+ * already expanding the zone...
+ *
+ * In either case wait for a thread to finish, then try again.
+ */
+ zone->waiting = TRUE;
+ zone_sleep(zone);
+ } else {
+ vm_offset_t space;
+ vm_size_t alloc_size;
+ int retry = 0;
+
+ if ((zone->cur_size + zone->elem_size) >
projects / apple / xnu.git / blobdiff