/** @file
  Data structure and functions to allocate and free memory space.

Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#ifndef _HEAPGUARD_H_
#define _HEAPGUARD_H_

#include "PiSmmCore.h"

//
// Following macros are used to define and access the guarded memory bitmap
// table.
//
// To simplify the access and reduce the memory used for this table, the
// table is constructed in the similar way as page table structure but in
// reverse direction, i.e. from bottom growing up to top.
//
//    - 1-bit tracks 1 page (4KB)
//    - 1-UINT64 map entry tracks 256KB memory
//    - 1K-UINT64 map table tracks 256MB memory
//    - Five levels of tables can track any address of memory of 64-bit
//      system, like below.
//
//       512   *   512   *   512   *   512    *    1K   *  64b *     4K
//    111111111 111111111 111111111 111111111 1111111111 111111 111111111111
//    63        54        45        36        27         17     11         0
//       9b        9b        9b        9b         10b      6b       12b
//       L0   ->   L1   ->   L2   ->   L3   ->    L4   -> bits  ->  page
//      1FF       1FF       1FF       1FF         3FF      3F       FFF
//
// L4 table has 1K * sizeof(UINT64) = 8K (2-page), which can track 256MB
// memory. Each table of L0-L3 will be allocated when its memory address
// range is to be tracked. Only 1-page will be allocated each time. This
// can save memories used to establish this map table.
//
// For a normal configuration of system with 4G memory, two levels of tables
// can track the whole memory, because two levels (L3+L4) of map tables have
// already coverred 37-bit of memory address. And for a normal UEFI BIOS,
// less than 128M memory would be consumed during boot. That means we just
// need
//
//          1-page (L3) + 2-page (L4)
//
// memory (3 pages) to track the memory allocation works. In this case,
// there's no need to setup L0-L2 tables.
//

//
// Each entry occupies 8B/64b. 1-page can hold 512 entries, which spans 9
// bits in address. (512 = 1 << 9)
//
#define BYTE_LENGTH_SHIFT                   3             // (8 = 1 << 3)

#define GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT  \
        (EFI_PAGE_SHIFT - BYTE_LENGTH_SHIFT)

#define GUARDED_HEAP_MAP_TABLE_DEPTH        5

// Use UINT64_index + bit_index_of_UINT64 to locate the bit in may
#define GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT    6             // (64 = 1 << 6)

#define GUARDED_HEAP_MAP_ENTRY_BITS         \
        (1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)

#define GUARDED_HEAP_MAP_ENTRY_BYTES        \
        (GUARDED_HEAP_MAP_ENTRY_BITS / 8)

// L4 table address width: 64 - 9 * 4 - 6 - 12 = 10b
#define GUARDED_HEAP_MAP_ENTRY_SHIFT              \
        (GUARDED_HEAP_MAP_ENTRY_BITS              \
         - GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 4 \
         - GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT       \
         - EFI_PAGE_SHIFT)

// L4 table address mask: (1 << 10 - 1) = 0x3FF
#define GUARDED_HEAP_MAP_ENTRY_MASK               \
        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1)

// Size of each L4 table: (1 << 10) * 8 = 8KB = 2-page
#define GUARDED_HEAP_MAP_SIZE                     \
        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) * GUARDED_HEAP_MAP_ENTRY_BYTES)

// Memory size tracked by one L4 table: 8KB * 8 * 4KB = 256MB
#define GUARDED_HEAP_MAP_UNIT_SIZE                \
        (GUARDED_HEAP_MAP_SIZE * 8 * EFI_PAGE_SIZE)

// L4 table entry number: 8KB / 8 = 1024
#define GUARDED_HEAP_MAP_ENTRIES_PER_UNIT         \
        (GUARDED_HEAP_MAP_SIZE / GUARDED_HEAP_MAP_ENTRY_BYTES)

// L4 table entry indexing
#define GUARDED_HEAP_MAP_ENTRY_INDEX(Address)                       \
        (RShiftU64 (Address, EFI_PAGE_SHIFT                         \
                             + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)    \
         & GUARDED_HEAP_MAP_ENTRY_MASK)

// L4 table entry bit indexing
#define GUARDED_HEAP_MAP_ENTRY_BIT_INDEX(Address)       \
        (RShiftU64 (Address, EFI_PAGE_SHIFT)            \
         & ((1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT) - 1))

//
// Total bits (pages) tracked by one L4 table (65536-bit)
//
#define GUARDED_HEAP_MAP_BITS                               \
        (1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
               + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT))

//
// Bit indexing inside the whole L4 table (0 - 65535)
//
#define GUARDED_HEAP_MAP_BIT_INDEX(Address)                     \
        (RShiftU64 (Address, EFI_PAGE_SHIFT)                    \
         & ((1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
                   + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)) - 1))

//
// Memory address bit width tracked by L4 table: 10 + 6 + 12 = 28
//
#define GUARDED_HEAP_MAP_TABLE_SHIFT                                      \
        (GUARDED_HEAP_MAP_ENTRY_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT  \
         + EFI_PAGE_SHIFT)

//
// Macro used to initialize the local array variable for map table traversing
// {55, 46, 37, 28, 18}
//
#define GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS                                 \
  {                                                                         \
    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 3,  \
    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 2,  \
    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT,      \
    GUARDED_HEAP_MAP_TABLE_SHIFT,                                           \
    EFI_PAGE_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT                       \
  }

//
// Masks used to extract address range of each level of table
// {0x1FF, 0x1FF, 0x1FF, 0x1FF, 0x3FF}
//
#define GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS                                  \
  {                                                                         \
    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
    (1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1                                 \
  }

//
// Memory type to guard (matching the related PCD definition)
//
#define GUARD_HEAP_TYPE_PAGE        BIT2
#define GUARD_HEAP_TYPE_POOL        BIT3

//
// Debug message level
//
#define HEAP_GUARD_DEBUG_LEVEL  (DEBUG_POOL|DEBUG_PAGE)

typedef struct {
  UINT32                TailMark;
  UINT32                HeadMark;
  EFI_PHYSICAL_ADDRESS  Address;
  LIST_ENTRY            Link;
} HEAP_GUARD_NODE;

/**
  Set head Guard and tail Guard for the given memory range.

  @param[in]  Memory          Base address of memory to set guard for.
  @param[in]  NumberOfPages   Memory size in pages.

  @return VOID.
**/
VOID
SetGuardForMemory (
  IN EFI_PHYSICAL_ADDRESS   Memory,
  IN UINTN                  NumberOfPages
  );

/**
  Unset head Guard and tail Guard for the given memory range.

  @param[in]  Memory          Base address of memory to unset guard for.
  @param[in]  NumberOfPages   Memory size in pages.

  @return VOID.
**/
VOID
UnsetGuardForMemory (
  IN EFI_PHYSICAL_ADDRESS   Memory,
  IN UINTN                  NumberOfPages
  );

/**
  Adjust the base and number of pages to really allocate according to Guard.

  @param[in,out]  Memory          Base address of free memory.
  @param[in,out]  NumberOfPages   Size of memory to allocate.

  @return VOID.
**/
VOID
AdjustMemoryA (
  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
  IN OUT UINTN                   *NumberOfPages
  );

/**
  Adjust the start address and number of pages to free according to Guard.

  The purpose of this function is to keep the shared Guard page with adjacent
  memory block if it's still in guard, or free it if no more sharing. Another
  is to reserve pages as Guard pages in partial page free situation.

  @param[in,out]  Memory          Base address of memory to free.
  @param[in,out]  NumberOfPages   Size of memory to free.

  @return VOID.
**/
VOID
AdjustMemoryF (
  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
  IN OUT UINTN                   *NumberOfPages
  );

/**
  Check to see if the pool at the given address should be guarded or not.

  @param[in]  MemoryType      Pool type to check.


  @return TRUE  The given type of pool should be guarded.
  @return FALSE The given type of pool should not be guarded.
**/
BOOLEAN
IsPoolTypeToGuard (
  IN EFI_MEMORY_TYPE        MemoryType
  );

/**
  Check to see if the page at the given address should be guarded or not.

  @param[in]  MemoryType      Page type to check.
  @param[in]  AllocateType    Allocation type to check.

  @return TRUE  The given type of page should be guarded.
  @return FALSE The given type of page should not be guarded.
**/
BOOLEAN
IsPageTypeToGuard (
  IN EFI_MEMORY_TYPE        MemoryType,
  IN EFI_ALLOCATE_TYPE      AllocateType
  );

/**
  Check to see if the page at the given address is guarded or not.

  @param[in]  Address     The address to check for.

  @return TRUE  The page at Address is guarded.
  @return FALSE The page at Address is not guarded.
**/
BOOLEAN
EFIAPI
IsMemoryGuarded (
  IN EFI_PHYSICAL_ADDRESS    Address
  );

/**
  Check to see if the page at the given address is a Guard page or not.

  @param[in]  Address     The address to check for.

  @return TRUE  The page at Address is a Guard page.
  @return FALSE The page at Address is not a Guard page.
**/
BOOLEAN
EFIAPI
IsGuardPage (
  IN EFI_PHYSICAL_ADDRESS    Address
  );

/**
  Dump the guarded memory bit map.
**/
VOID
EFIAPI
DumpGuardedMemoryBitmap (
  VOID
  );

/**
  Adjust the pool head position to make sure the Guard page is adjavent to
  pool tail or pool head.

  @param[in]  Memory    Base address of memory allocated.
  @param[in]  NoPages   Number of pages actually allocated.
  @param[in]  Size      Size of memory requested.
                        (plus pool head/tail overhead)

  @return Address of pool head.
**/
VOID *
AdjustPoolHeadA (
  IN EFI_PHYSICAL_ADDRESS    Memory,
  IN UINTN                   NoPages,
  IN UINTN                   Size
  );

/**
  Get the page base address according to pool head address.

  @param[in]  Memory    Head address of pool to free.

  @return Address of pool head.
**/
VOID *
AdjustPoolHeadF (
  IN EFI_PHYSICAL_ADDRESS    Memory
  );

/**
  Helper function of memory allocation with Guard pages.

  @param  FreePageList           The free page node.
  @param  NumberOfPages          Number of pages to be allocated.
  @param  MaxAddress             Request to allocate memory below this address.
  @param  MemoryType             Type of memory requested.

  @return Memory address of allocated pages.
**/
UINTN
InternalAllocMaxAddressWithGuard (
  IN OUT LIST_ENTRY           *FreePageList,
  IN     UINTN                NumberOfPages,
  IN     UINTN                MaxAddress,
  IN     EFI_MEMORY_TYPE      MemoryType
  );

/**
  Helper function of memory free with Guard pages.

  @param[in]  Memory                 Base address of memory being freed.
  @param[in]  NumberOfPages          The number of pages to free.
  @param[in]  AddRegion              If this memory is new added region.

  @retval EFI_NOT_FOUND          Could not find the entry that covers the range.
  @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or
                                 NumberOfPages is zero.
  @return EFI_SUCCESS            Pages successfully freed.
**/
EFI_STATUS
SmmInternalFreePagesExWithGuard (
  IN EFI_PHYSICAL_ADDRESS  Memory,
  IN UINTN                 NumberOfPages,
  IN BOOLEAN               AddRegion
  );

/**
  Check to see if the heap guard is enabled for page and/or pool allocation.

  @return TRUE/FALSE.
**/
BOOLEAN
IsHeapGuardEnabled (
  VOID
  );

/**
  Debug function used to verify if the Guard page is well set or not.

  @param[in]  BaseAddress     Address of memory to check.
  @param[in]  NumberOfPages   Size of memory in pages.

  @return TRUE    The head Guard and tail Guard are both well set.
  @return FALSE   The head Guard and/or tail Guard are not well set.
**/
BOOLEAN
VerifyMemoryGuard (
  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
  IN  UINTN                     NumberOfPages
  );

extern BOOLEAN mOnGuarding;

#endif