Atmosphere/libraries/libmesosphere/include/mesosphere/kern_k_page_table_base.hpp

407 lines
26 KiB
C++

/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <mesosphere/kern_common.hpp>
#include <mesosphere/kern_select_page_table_impl.hpp>
#include <mesosphere/kern_k_light_lock.hpp>
#include <mesosphere/kern_k_page_group.hpp>
#include <mesosphere/kern_k_memory_manager.hpp>
#include <mesosphere/kern_k_memory_layout.hpp>
#include <mesosphere/kern_k_memory_block_manager.hpp>
namespace ams::kern {
struct KPageProperties {
KMemoryPermission perm;
bool io;
bool uncached;
bool non_contiguous;
};
static_assert(std::is_trivial<KPageProperties>::value);
class KPageTableBase {
NON_COPYABLE(KPageTableBase);
NON_MOVEABLE(KPageTableBase);
public:
using TraversalEntry = KPageTableImpl::TraversalEntry;
using TraversalContext = KPageTableImpl::TraversalContext;
protected:
enum MemoryFillValue {
MemoryFillValue_Zero = 0,
MemoryFillValue_Stack = 'X',
MemoryFillValue_Ipc = 'Y',
MemoryFillValue_Heap = 'Z',
};
enum OperationType {
OperationType_Map = 0,
OperationType_MapGroup = 1,
OperationType_Unmap = 2,
OperationType_ChangePermissions = 3,
OperationType_ChangePermissionsAndRefresh = 4,
};
static constexpr size_t MaxPhysicalMapAlignment = 1_GB;
static constexpr size_t RegionAlignment = 2_MB;
static_assert(RegionAlignment == KernelAslrAlignment);
struct PageLinkedList {
private:
struct Node {
Node *next;
u8 buffer[PageSize - sizeof(Node *)];
};
static_assert(util::is_pod<Node>::value);
private:
Node *root;
public:
constexpr PageLinkedList() : root(nullptr) { /* ... */ }
void Push(Node *n) {
MESOSPHERE_ASSERT(util::IsAligned(reinterpret_cast<uintptr_t>(n), PageSize));
n->next = this->root;
this->root = n;
}
void Push(KVirtualAddress addr) {
this->Push(GetPointer<Node>(addr));
}
Node *Peek() const { return this->root; }
Node *Pop() {
Node *r = this->root;
this->root = this->root->next;
return r;
}
};
static_assert(std::is_trivially_destructible<PageLinkedList>::value);
static constexpr u32 DefaultMemoryIgnoreAttr = KMemoryAttribute_IpcLocked | KMemoryAttribute_DeviceShared;
static constexpr size_t GetAddressSpaceWidth(ams::svc::CreateProcessFlag as_type) {
switch (static_cast<ams::svc::CreateProcessFlag>(as_type & ams::svc::CreateProcessFlag_AddressSpaceMask)) {
case ams::svc::CreateProcessFlag_AddressSpace64Bit:
return 39;
case ams::svc::CreateProcessFlag_AddressSpace64BitDeprecated:
return 36;
case ams::svc::CreateProcessFlag_AddressSpace32Bit:
case ams::svc::CreateProcessFlag_AddressSpace32BitWithoutAlias:
return 32;
MESOSPHERE_UNREACHABLE_DEFAULT_CASE();
}
}
private:
class KScopedPageTableUpdater {
private:
KPageTableBase *page_table;
PageLinkedList ll;
public:
ALWAYS_INLINE explicit KScopedPageTableUpdater(KPageTableBase *pt) : page_table(pt), ll() { /* ... */ }
ALWAYS_INLINE explicit KScopedPageTableUpdater(KPageTableBase &pt) : KScopedPageTableUpdater(std::addressof(pt)) { /* ... */ }
ALWAYS_INLINE ~KScopedPageTableUpdater() { this->page_table->FinalizeUpdate(this->GetPageList()); }
PageLinkedList *GetPageList() { return std::addressof(this->ll); }
};
private:
KProcessAddress address_space_start;
KProcessAddress address_space_end;
KProcessAddress heap_region_start;
KProcessAddress heap_region_end;
KProcessAddress current_heap_end;
KProcessAddress alias_region_start;
KProcessAddress alias_region_end;
KProcessAddress stack_region_start;
KProcessAddress stack_region_end;
KProcessAddress kernel_map_region_start;
KProcessAddress kernel_map_region_end;
KProcessAddress alias_code_region_start;
KProcessAddress alias_code_region_end;
KProcessAddress code_region_start;
KProcessAddress code_region_end;
size_t max_heap_size;
size_t mapped_physical_memory_size;
size_t mapped_unsafe_physical_memory;
mutable KLightLock general_lock;
mutable KLightLock map_physical_memory_lock;
KPageTableImpl impl;
KMemoryBlockManager memory_block_manager;
u32 allocate_option;
u32 address_space_width;
bool is_kernel;
bool enable_aslr;
KMemoryBlockSlabManager *memory_block_slab_manager;
KBlockInfoManager *block_info_manager;
const KMemoryRegion *cached_physical_linear_region;
const KMemoryRegion *cached_physical_heap_region;
const KMemoryRegion *cached_virtual_heap_region;
MemoryFillValue heap_fill_value;
MemoryFillValue ipc_fill_value;
MemoryFillValue stack_fill_value;
public:
constexpr KPageTableBase() :
address_space_start(), address_space_end(), heap_region_start(), heap_region_end(), current_heap_end(),
alias_region_start(), alias_region_end(), stack_region_start(), stack_region_end(), kernel_map_region_start(),
kernel_map_region_end(), alias_code_region_start(), alias_code_region_end(), code_region_start(), code_region_end(),
max_heap_size(), mapped_physical_memory_size(), mapped_unsafe_physical_memory(), general_lock(), map_physical_memory_lock(),
impl(), memory_block_manager(), allocate_option(), address_space_width(), is_kernel(), enable_aslr(), memory_block_slab_manager(),
block_info_manager(), cached_physical_linear_region(), cached_physical_heap_region(), cached_virtual_heap_region(),
heap_fill_value(), ipc_fill_value(), stack_fill_value()
{
/* ... */
}
NOINLINE Result InitializeForKernel(bool is_64_bit, void *table, KVirtualAddress start, KVirtualAddress end);
NOINLINE Result InitializeForProcess(ams::svc::CreateProcessFlag as_type, bool enable_aslr, bool from_back, KMemoryManager::Pool pool, void *table, KProcessAddress start, KProcessAddress end, KProcessAddress code_address, size_t code_size, KMemoryBlockSlabManager *mem_block_slab_manager, KBlockInfoManager *block_info_manager);
void Finalize();
constexpr bool IsKernel() const { return this->is_kernel; }
constexpr bool IsAslrEnabled() const { return this->enable_aslr; }
constexpr bool Contains(KProcessAddress addr) const {
return this->address_space_start <= addr && addr <= this->address_space_end - 1;
}
constexpr bool Contains(KProcessAddress addr, size_t size) const {
return this->address_space_start <= addr && addr < addr + size && addr + size - 1 <= this->address_space_end - 1;
}
constexpr bool IsInAliasRegion(KProcessAddress addr, size_t size) const {
return this->Contains(addr, size) && this->alias_region_start <= addr && addr + size - 1 <= this->alias_region_end - 1;
}
bool IsInUnsafeAliasRegion(KProcessAddress addr, size_t size) const {
/* Even though Unsafe physical memory is KMemoryState_Normal, it must be mapped inside the alias code region. */
return this->CanContain(addr, size, KMemoryState_AliasCode);
}
KProcessAddress GetRegionAddress(KMemoryState state) const;
size_t GetRegionSize(KMemoryState state) const;
bool CanContain(KProcessAddress addr, size_t size, KMemoryState state) const;
protected:
virtual Result Operate(PageLinkedList *page_list, KProcessAddress virt_addr, size_t num_pages, KPhysicalAddress phys_addr, bool is_pa_valid, const KPageProperties properties, OperationType operation, bool reuse_ll) = 0;
virtual Result Operate(PageLinkedList *page_list, KProcessAddress virt_addr, size_t num_pages, const KPageGroup &page_group, const KPageProperties properties, OperationType operation, bool reuse_ll) = 0;
virtual void FinalizeUpdate(PageLinkedList *page_list) = 0;
KPageTableImpl &GetImpl() { return this->impl; }
const KPageTableImpl &GetImpl() const { return this->impl; }
bool IsLockedByCurrentThread() const { return this->general_lock.IsLockedByCurrentThread(); }
bool IsLinearMappedPhysicalAddress(KPhysicalAddress phys_addr) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsLinearMappedPhysicalAddress(std::addressof(this->cached_physical_linear_region), phys_addr, this->cached_physical_linear_region);
}
bool IsLinearMappedPhysicalAddress(KPhysicalAddress phys_addr, size_t size) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsLinearMappedPhysicalAddress(std::addressof(this->cached_physical_linear_region), phys_addr, size, this->cached_physical_linear_region);
}
bool IsHeapPhysicalAddress(KPhysicalAddress phys_addr) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsHeapPhysicalAddress(std::addressof(this->cached_physical_heap_region), phys_addr, this->cached_physical_heap_region);
}
bool IsHeapPhysicalAddressForFinalize(KPhysicalAddress phys_addr) {
MESOSPHERE_ASSERT(!this->IsLockedByCurrentThread());
return KMemoryLayout::IsHeapPhysicalAddress(std::addressof(this->cached_physical_heap_region), phys_addr, this->cached_physical_heap_region);
}
bool IsHeapPhysicalAddress(KPhysicalAddress phys_addr, size_t size) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsHeapPhysicalAddress(std::addressof(this->cached_physical_heap_region), phys_addr, size, this->cached_physical_heap_region);
}
bool IsHeapVirtualAddress(KVirtualAddress virt_addr) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsHeapVirtualAddress(std::addressof(this->cached_virtual_heap_region), virt_addr, this->cached_virtual_heap_region);
}
bool IsHeapVirtualAddress(KVirtualAddress virt_addr, size_t size) {
MESOSPHERE_ASSERT(this->IsLockedByCurrentThread());
return KMemoryLayout::IsHeapVirtualAddress(std::addressof(this->cached_virtual_heap_region), virt_addr, size, this->cached_virtual_heap_region);
}
bool ContainsPages(KProcessAddress addr, size_t num_pages) const {
return (this->address_space_start <= addr) && (num_pages <= (this->address_space_end - this->address_space_start) / PageSize) && (addr + num_pages * PageSize - 1 <= this->address_space_end - 1);
}
private:
constexpr size_t GetNumGuardPages() const { return this->IsKernel() ? 1 : 4; }
ALWAYS_INLINE KProcessAddress FindFreeArea(KProcessAddress region_start, size_t region_num_pages, size_t num_pages, size_t alignment, size_t offset, size_t guard_pages) const;
Result CheckMemoryStateContiguous(KProcessAddress addr, size_t size, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr) const;
Result CheckMemoryState(const KMemoryInfo &info, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr) const;
Result CheckMemoryState(KMemoryState *out_state, KMemoryPermission *out_perm, KMemoryAttribute *out_attr, KProcessAddress addr, size_t size, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr, u32 ignore_attr = DefaultMemoryIgnoreAttr) const;
Result CheckMemoryState(KProcessAddress addr, size_t size, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr, u32 ignore_attr = DefaultMemoryIgnoreAttr) const {
return this->CheckMemoryState(nullptr, nullptr, nullptr, addr, size, state_mask, state, perm_mask, perm, attr_mask, attr, ignore_attr);
}
Result LockMemoryAndOpen(KPageGroup *out_pg, KPhysicalAddress *out_paddr, KProcessAddress addr, size_t size, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr, KMemoryPermission new_perm, u32 lock_attr);
Result UnlockMemory(KProcessAddress addr, size_t size, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr, KMemoryPermission new_perm, u32 lock_attr, const KPageGroup *pg);
Result QueryInfoImpl(KMemoryInfo *out_info, ams::svc::PageInfo *out_page, KProcessAddress address) const;
Result QueryMappingImpl(KProcessAddress *out, KPhysicalAddress address, size_t size, KMemoryState state) const;
Result AllocateAndMapPagesImpl(PageLinkedList *page_list, KProcessAddress address, size_t num_pages, const KPageProperties properties);
Result MapPageGroupImpl(PageLinkedList *page_list, KProcessAddress address, const KPageGroup &pg, const KPageProperties properties, bool reuse_ll);
Result MakePageGroup(KPageGroup &pg, KProcessAddress addr, size_t num_pages);
bool IsValidPageGroup(const KPageGroup &pg, KProcessAddress addr, size_t num_pages);
NOINLINE Result MapPages(KProcessAddress *out_addr, size_t num_pages, size_t alignment, KPhysicalAddress phys_addr, bool is_pa_valid, KProcessAddress region_start, size_t region_num_pages, KMemoryState state, KMemoryPermission perm);
Result SetupForIpcClient(PageLinkedList *page_list, KProcessAddress address, size_t size, KMemoryPermission test_perm, KMemoryState dst_state);
Result SetupForIpcServer(KProcessAddress *out_addr, size_t size, KProcessAddress src_addr, KMemoryPermission test_perm, KMemoryState dst_state, KPageTableBase &src_page_table, bool send);
Result CleanupForIpcClientOnServerSetupFailure(PageLinkedList *page_list, KProcessAddress address, size_t size, KMemoryPermission test_perm);
public:
bool GetPhysicalAddress(KPhysicalAddress *out, KProcessAddress virt_addr) const {
return this->GetImpl().GetPhysicalAddress(out, virt_addr);
}
KBlockInfoManager *GetBlockInfoManager() const { return this->block_info_manager; }
Result SetMemoryPermission(KProcessAddress addr, size_t size, ams::svc::MemoryPermission perm);
Result SetProcessMemoryPermission(KProcessAddress addr, size_t size, ams::svc::MemoryPermission perm);
Result SetMemoryAttribute(KProcessAddress addr, size_t size, u32 mask, u32 attr);
Result SetHeapSize(KProcessAddress *out, size_t size);
Result SetMaxHeapSize(size_t size);
Result QueryInfo(KMemoryInfo *out_info, ams::svc::PageInfo *out_page_info, KProcessAddress addr) const;
Result QueryStaticMapping(KProcessAddress *out, KPhysicalAddress address, size_t size) const { return this->QueryMappingImpl(out, address, size, KMemoryState_Static); }
Result QueryIoMapping(KProcessAddress *out, KPhysicalAddress address, size_t size) const { return this->QueryMappingImpl(out, address, size, KMemoryState_Io); }
Result MapMemory(KProcessAddress dst_address, KProcessAddress src_address, size_t size);
Result UnmapMemory(KProcessAddress dst_address, KProcessAddress src_address, size_t size);
Result MapCodeMemory(KProcessAddress dst_address, KProcessAddress src_address, size_t size);
Result UnmapCodeMemory(KProcessAddress dst_address, KProcessAddress src_address, size_t size);
Result MapIo(KPhysicalAddress phys_addr, size_t size, KMemoryPermission perm);
Result MapStatic(KPhysicalAddress phys_addr, size_t size, KMemoryPermission perm);
Result MapRegion(KMemoryRegionType region_type, KMemoryPermission perm);
Result MapPages(KProcessAddress *out_addr, size_t num_pages, size_t alignment, KPhysicalAddress phys_addr, KProcessAddress region_start, size_t region_num_pages, KMemoryState state, KMemoryPermission perm) {
return this->MapPages(out_addr, num_pages, alignment, phys_addr, true, region_start, region_num_pages, state, perm);
}
Result MapPages(KProcessAddress *out_addr, size_t num_pages, size_t alignment, KPhysicalAddress phys_addr, KMemoryState state, KMemoryPermission perm) {
return this->MapPages(out_addr, num_pages, alignment, phys_addr, true, this->GetRegionAddress(state), this->GetRegionSize(state) / PageSize, state, perm);
}
Result MapPages(KProcessAddress *out_addr, size_t num_pages, KMemoryState state, KMemoryPermission perm) {
return this->MapPages(out_addr, num_pages, PageSize, Null<KPhysicalAddress>, false, this->GetRegionAddress(state), this->GetRegionSize(state) / PageSize, state, perm);
}
Result MapPages(KProcessAddress address, size_t num_pages, KMemoryState state, KMemoryPermission perm);
Result UnmapPages(KProcessAddress address, size_t num_pages, KMemoryState state);
Result MapPageGroup(KProcessAddress *out_addr, const KPageGroup &pg, KProcessAddress region_start, size_t region_num_pages, KMemoryState state, KMemoryPermission perm);
Result MapPageGroup(KProcessAddress address, const KPageGroup &pg, KMemoryState state, KMemoryPermission perm);
Result UnmapPageGroup(KProcessAddress address, const KPageGroup &pg, KMemoryState state);
Result MakeAndOpenPageGroup(KPageGroup *out, KProcessAddress address, size_t num_pages, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr);
Result MakeAndOpenPageGroupContiguous(KPageGroup *out, KProcessAddress address, size_t num_pages, u32 state_mask, u32 state, u32 perm_mask, u32 perm, u32 attr_mask, u32 attr);
Result InvalidateProcessDataCache(KProcessAddress address, size_t size);
Result LockForDeviceAddressSpace(KPageGroup *out, KProcessAddress address, size_t size, KMemoryPermission perm, bool is_aligned);
Result UnlockForDeviceAddressSpace(KProcessAddress address, size_t size);
Result LockForIpcUserBuffer(KPhysicalAddress *out, KProcessAddress address, size_t size);
Result UnlockForIpcUserBuffer(KProcessAddress address, size_t size);
Result LockForTransferMemory(KPageGroup *out, KProcessAddress address, size_t size, KMemoryPermission perm);
Result UnlockForTransferMemory(KProcessAddress address, size_t size, const KPageGroup &pg);
Result LockForCodeMemory(KPageGroup *out, KProcessAddress address, size_t size, KMemoryPermission perm);
Result UnlockForCodeMemory(KProcessAddress address, size_t size, const KPageGroup &pg);
Result CopyMemoryFromLinearToUser(KProcessAddress dst_addr, size_t size, KProcessAddress src_addr, u32 src_state_mask, u32 src_state, KMemoryPermission src_test_perm, u32 src_attr_mask, u32 src_attr);
Result CopyMemoryFromLinearToKernel(KProcessAddress dst_addr, size_t size, KProcessAddress src_addr, u32 src_state_mask, u32 src_state, KMemoryPermission src_test_perm, u32 src_attr_mask, u32 src_attr);
Result CopyMemoryFromUserToLinear(KProcessAddress dst_addr, size_t size, u32 dst_state_mask, u32 dst_state, KMemoryPermission dst_test_perm, u32 dst_attr_mask, u32 dst_attr, KProcessAddress src_addr);
Result CopyMemoryFromKernelToLinear(KProcessAddress dst_addr, size_t size, u32 dst_state_mask, u32 dst_state, KMemoryPermission dst_test_perm, u32 dst_attr_mask, u32 dst_attr, KProcessAddress src_addr);
Result CopyMemoryFromHeapToHeap(KPageTableBase &dst_page_table, KProcessAddress dst_addr, size_t size, u32 dst_state_mask, u32 dst_state, KMemoryPermission dst_test_perm, u32 dst_attr_mask, u32 dst_attr, KProcessAddress src_addr, u32 src_state_mask, u32 src_state, KMemoryPermission src_test_perm, u32 src_attr_mask, u32 src_attr);
Result CopyMemoryFromHeapToHeapWithoutCheckDestination(KPageTableBase &dst_page_table, KProcessAddress dst_addr, size_t size, u32 dst_state_mask, u32 dst_state, KMemoryPermission dst_test_perm, u32 dst_attr_mask, u32 dst_attr, KProcessAddress src_addr, u32 src_state_mask, u32 src_state, KMemoryPermission src_test_perm, u32 src_attr_mask, u32 src_attr);
Result SetupForIpc(KProcessAddress *out_dst_addr, size_t size, KProcessAddress src_addr, KPageTableBase &src_page_table, KMemoryPermission test_perm, KMemoryState dst_state, bool send);
Result CleanupForIpcServer(KProcessAddress address, size_t size, KMemoryState dst_state, KProcess *server_process);
Result CleanupForIpcClient(KProcessAddress address, size_t size, KMemoryState dst_state);
Result MapPhysicalMemory(KProcessAddress address, size_t size);
Result UnmapPhysicalMemory(KProcessAddress address, size_t size);
Result MapPhysicalMemoryUnsafe(KProcessAddress address, size_t size);
Result UnmapPhysicalMemoryUnsafe(KProcessAddress address, size_t size);
void DumpTable() const {
KScopedLightLock lk(this->general_lock);
this->GetImpl().Dump(GetInteger(this->address_space_start), this->address_space_end - this->address_space_start);
}
public:
KProcessAddress GetAddressSpaceStart() const { return this->address_space_start; }
KProcessAddress GetHeapRegionStart() const { return this->heap_region_start; }
KProcessAddress GetAliasRegionStart() const { return this->alias_region_start; }
KProcessAddress GetStackRegionStart() const { return this->stack_region_start; }
KProcessAddress GetKernelMapRegionStart() const { return this->kernel_map_region_start; }
KProcessAddress GetAliasCodeRegionStart() const { return this->alias_code_region_start; }
size_t GetAddressSpaceSize() const { return this->address_space_end - this->address_space_start; }
size_t GetHeapRegionSize() const { return this->heap_region_end - this->heap_region_start; }
size_t GetAliasRegionSize() const { return this->alias_region_end - this->alias_region_start; }
size_t GetStackRegionSize() const { return this->stack_region_end - this->stack_region_start; }
size_t GetKernelMapRegionSize() const { return this->kernel_map_region_end - this->kernel_map_region_start; }
size_t GetAliasCodeRegionSize() const { return this->alias_code_region_end - this->alias_code_region_start; }
size_t GetNormalMemorySize() const {
/* Lock the table. */
KScopedLightLock lk(this->general_lock);
return (this->current_heap_end - this->heap_region_start) + this->mapped_physical_memory_size;
}
u32 GetAllocateOption() const { return this->allocate_option; }
public:
static ALWAYS_INLINE KVirtualAddress GetLinearMappedVirtualAddress(KPhysicalAddress addr) {
return KMemoryLayout::GetLinearVirtualAddress(addr);
}
static ALWAYS_INLINE KPhysicalAddress GetLinearMappedPhysicalAddress(KVirtualAddress addr) {
return KMemoryLayout::GetLinearPhysicalAddress(addr);
}
static ALWAYS_INLINE KVirtualAddress GetHeapVirtualAddress(KPhysicalAddress addr) {
return GetLinearMappedVirtualAddress(addr);
}
static ALWAYS_INLINE KPhysicalAddress GetHeapPhysicalAddress(KVirtualAddress addr) {
return GetLinearMappedPhysicalAddress(addr);
}
static ALWAYS_INLINE KVirtualAddress GetPageTableVirtualAddress(KPhysicalAddress addr) {
return GetLinearMappedVirtualAddress(addr);
}
static ALWAYS_INLINE KPhysicalAddress GetPageTablePhysicalAddress(KVirtualAddress addr) {
return GetLinearMappedPhysicalAddress(addr);
}
};
}