OvmfPkg/Fdt/HighMemDxe/HighMemDxe.c

   1 /** @file
   2 *  High memory node enumeration DXE driver for ARM and RISC-V
   3 *  Virtual Machines
   4 *
   5 *  Copyright (c) 2015-2016, Linaro Ltd. All rights reserved.
   6 *
   7 *  SPDX-License-Identifier: BSD-2-Clause-Patent
   8 *
   9 **/
  10
  11 #include <Library/BaseLib.h>
  12 #include <Library/DebugLib.h>
  13 #include <Library/DxeServicesTableLib.h>
  14 #include <Library/PcdLib.h>
  15 #include <Library/UefiBootServicesTableLib.h>
  16
  17 #include <Protocol/Cpu.h>
  18 #include <Protocol/FdtClient.h>
  19
  20 EFI_STATUS
  21 EFIAPI
  22 InitializeHighMemDxe (
  23   IN EFI_HANDLE           ImageHandle,
  24   IN EFI_SYSTEM_TABLE     *SystemTable
  25   )
  26 {
  27   FDT_CLIENT_PROTOCOL               *FdtClient;
  28   EFI_CPU_ARCH_PROTOCOL             *Cpu;
  29   EFI_STATUS                        Status, FindNodeStatus;
  30   INT32                             Node;
  31   CONST UINT32                      *Reg;
  32   UINT32                            RegSize;
  33   UINTN                             AddressCells, SizeCells;
  34   UINT64                            CurBase;
  35   UINT64                            CurSize;
  36   UINT64                            Attributes;
  37   EFI_GCD_MEMORY_SPACE_DESCRIPTOR   GcdDescriptor;
  38
  39   Status = gBS->LocateProtocol (&gFdtClientProtocolGuid, NULL,
  40                   (VOID **)&FdtClient);
  41   ASSERT_EFI_ERROR (Status);
  42
  43   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL,
  44                   (VOID **)&Cpu);
  45   ASSERT_EFI_ERROR (Status);
  46
  47   //
  48   // Check for memory node and add the memory spaces except the lowest one
  49   //
  50   for (FindNodeStatus = FdtClient->FindMemoryNodeReg (FdtClient, &Node,
  51                                      (CONST VOID **) &Reg, &AddressCells,
  52                                      &SizeCells, &RegSize);
  53        !EFI_ERROR (FindNodeStatus);
  54        FindNodeStatus = FdtClient->FindNextMemoryNodeReg (FdtClient, Node,
  55                                      &Node, (CONST VOID **) &Reg, &AddressCells,
  56                                      &SizeCells, &RegSize)) {
  57     ASSERT (AddressCells <= 2);
  58     ASSERT (SizeCells <= 2);
  59
  60     while (RegSize > 0) {
  61       CurBase = SwapBytes32 (*Reg++);
  62       if (AddressCells > 1) {
  63         CurBase = (CurBase << 32) | SwapBytes32 (*Reg++);
  64       }
  65       CurSize = SwapBytes32 (*Reg++);
  66       if (SizeCells > 1) {
  67         CurSize = (CurSize << 32) | SwapBytes32 (*Reg++);
  68       }
  69       RegSize -= (AddressCells + SizeCells) * sizeof (UINT32);
  70
  71       Status = gDS->GetMemorySpaceDescriptor (CurBase, &GcdDescriptor);
  72       if (EFI_ERROR (Status)) {
  73         DEBUG ((DEBUG_WARN,
  74           "%a: Region 0x%lx - 0x%lx not found in the GCD memory space map\n",
  75           __FUNCTION__, CurBase, CurBase + CurSize - 1));
  76           continue;
  77       }
  78       if (GcdDescriptor.GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
  79         Status = gDS->AddMemorySpace (EfiGcdMemoryTypeSystemMemory, CurBase,
  80                         CurSize, EFI_MEMORY_WB);
  81
  82         if (EFI_ERROR (Status)) {
  83           DEBUG ((DEBUG_ERROR,
  84             "%a: Failed to add System RAM @ 0x%lx - 0x%lx (%r)\n",
  85             __FUNCTION__, CurBase, CurBase + CurSize - 1, Status));
  86           continue;
  87         }
  88
  89         Status = gDS->SetMemorySpaceAttributes (CurBase, CurSize,
  90                         EFI_MEMORY_WB);
  91         if (EFI_ERROR (Status)) {
  92           DEBUG ((DEBUG_WARN,
  93             "%a: gDS->SetMemorySpaceAttributes() failed on region 0x%lx - 0x%lx (%r)\n",
  94             __FUNCTION__, CurBase, CurBase + CurSize - 1, Status));
  95         }
  96
  97         //
  98         // Due to the ambiguous nature of the RO/XP GCD memory space attributes,
  99         // it is impossible to add a memory space with the XP attribute in a way
 100         // that does not result in the XP attribute being set on *all* UEFI
 101         // memory map entries that are carved from it, including code regions
 102         // that require executable permissions.
 103         //
 104         // So instead, we never set the RO/XP attributes in the GCD memory space
 105         // capabilities or attribute fields, and apply any protections directly
 106         // on the page table mappings by going through the cpu arch protocol.
 107         //
 108         Attributes = EFI_MEMORY_WB;
 109         if ((PcdGet64 (PcdDxeNxMemoryProtectionPolicy) &
 110              (1U << (UINT32)EfiConventionalMemory)) != 0) {
 111           Attributes |= EFI_MEMORY_XP;
 112         }
 113
 114         Status = Cpu->SetMemoryAttributes (Cpu, CurBase, CurSize, Attributes);
 115
 116         if (EFI_ERROR (Status)) {
 117           DEBUG ((DEBUG_ERROR,
 118             "%a: Failed to set System RAM @ 0x%lx - 0x%lx attribute (%r)\n",
 119             __FUNCTION__, CurBase, CurBase + CurSize - 1, Status));
 120         } else {
 121           DEBUG ((DEBUG_INFO, "%a: Add System RAM @ 0x%lx - 0x%lx\n",
 122             __FUNCTION__, CurBase, CurBase + CurSize - 1));
 123         }
 124       }
 125     }
 126   }
 127
 128   return EFI_SUCCESS;
 129 }