Ring3: Added support for IA32 User page table.

MdeModulePkg/Core/Dxe/DxeMain.inf

@@ -225,7 +225,7 @@
   gEfiMdePkgTokenSpaceGuid.PcdImageProtectionPolicy                         ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseMmio                           ## CONSUMES
 
-[Pcd.IA32,Pcd.X64]
+[Pcd.IA32, Pcd.X64]
   gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable                          ## SOMETIMES_CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdUse5LevelPageTable                      ## SOMETIMES_CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask        ## CONSUMES

MdeModulePkg/Core/Dxe/SysCall/IA32/CoreBootServices.nasm

@@ -98,6 +98,10 @@ copy:
     pop     eax
 %endmacro
 
+ALIGN   4096
+global ASM_PFX(SysCallBase)
+ASM_PFX(SysCallBase):
+
 ;------------------------------------------------------------------------------
 ; EFI_STATUS
 ; EFIAPI
@@ -119,6 +123,9 @@ ASM_PFX(CoreBootServices):
     push    ebp
     push    eax
 
+    mov     eax, [ASM_PFX(gCorePageTable)]
+    mov     cr3, eax
+
     ; Switch from User to Core data segment selectors.
     mov     ax, ss
     mov     ds, ax
@@ -147,6 +154,9 @@ ASM_PFX(CoreBootServices):
 
     SetRing3DataSegmentSelectors
 
+    mov     eax, [ASM_PFX(gUserPageTable)]
+    mov     cr3, eax
+
     pop     eax
 
     ; Step over User Arguments [1..3] and CallBootService input.
@@ -194,10 +204,17 @@ ASM_PFX(CallRing3):
     ; Switch to User Stack.
     mov     ebp, ecx
 
+    mov     ebx, [ASM_PFX(gUserPageTable)]
+    mov     cr3, ebx
+
     ; Pass control to user image
     sti
     sysexit
 
+ALIGN   4096
+global ASM_PFX(SysCallEnd)
+ASM_PFX(SysCallEnd):
+
 ;------------------------------------------------------------------------------
 ; VOID
 ; EFIAPI
@@ -219,5 +236,16 @@ ASM_PFX(ReturnToCore):
     ret
 
 SECTION .data
+ALIGN   4096
+
+global ASM_PFX(gCorePageTable)
+ASM_PFX(gCorePageTable):
+  resd 1
+
+global ASM_PFX(gUserPageTable)
+ASM_PFX(gUserPageTable):
+  resd 1
+
+ALIGN   4096
 ASM_PFX(CoreEsp):
   resd 1

MdeModulePkg/Core/Dxe/SysCall/IA32/InitializeIA32.c

@@ -8,6 +8,86 @@
 #include "DxeMain.h"
 
 #include <Register/Intel/ArchitecturalMsr.h>
+#include <IndustryStandard/PageTable.h>
+
+VOID
+EFIAPI
+MakeUserPageTableTemplate (
+  OUT VOID   **UserPageTableTemplate,
+  OUT UINTN  *UserPageTableTemplateSize
+  )
+{
+  UINT8                           PhysicalAddressBits;
+  EFI_PHYSICAL_ADDRESS            PhysicalAddress;
+  UINTN                           IndexOfPdpEntries;
+  UINTN                           IndexOfPageDirectoryEntries;
+  UINT32                          NumberOfPdpEntriesNeeded;
+  PAGE_MAP_AND_DIRECTORY_POINTER  *PageMap;
+  PAGE_MAP_AND_DIRECTORY_POINTER  *PageDirectoryPointerEntry;
+  PAGE_TABLE_ENTRY                *PageDirectoryEntry;
+  UINTN                           TotalPagesNum;
+  UINTN                           PageAddress;
+  UINT64                          AddressEncMask;
+
+  //
+  // Make sure AddressEncMask is contained to smallest supported address field
+  //
+  AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
+
+  PhysicalAddressBits = 32;
+
+  //
+  // Calculate the table entries needed.
+  //
+  NumberOfPdpEntriesNeeded = (UINT32)LShiftU64 (1, (PhysicalAddressBits - 30));
+
+  TotalPagesNum = NumberOfPdpEntriesNeeded + 1;
+  PageAddress   = (UINTN)AllocateAlignedPages (TotalPagesNum, PAGE_TABLE_POOL_ALIGNMENT);
+  ASSERT (PageAddress != 0);
+
+  PageMap      = (VOID *)PageAddress;
+  PageAddress += SIZE_4KB;
+
+  PageDirectoryPointerEntry = PageMap;
+  PhysicalAddress           = 0;
+
+  for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
+    //
+    // Each Directory Pointer entries points to a page of Page Directory entires.
+    // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.
+    //
+    PageDirectoryEntry = (VOID *)PageAddress;
+    PageAddress       += SIZE_4KB;
+
+    //
+    // Fill in a Page Directory Pointer Entries
+    //
+    PageDirectoryPointerEntry->Uint64       = (UINT64)(UINTN)PageDirectoryEntry | AddressEncMask;
+    PageDirectoryPointerEntry->Bits.Present = 1;
+
+    for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress += SIZE_2MB) {
+      //
+      // Fill in the Page Directory entries
+      //
+      PageDirectoryEntry->Uint64         = (UINT64)PhysicalAddress | AddressEncMask;
+      PageDirectoryEntry->Bits.ReadWrite = 1;
+      PageDirectoryEntry->Bits.Present   = 0;
+      PageDirectoryEntry->Bits.MustBe1   = 1;
+    }
+  }
+
+  for ( ; IndexOfPdpEntries < 512; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
+    ZeroMem (
+      PageDirectoryPointerEntry,
+      sizeof (PAGE_MAP_AND_DIRECTORY_POINTER)
+      );
+  }
+
+  *UserPageTableTemplate     = (VOID *)PageMap;
+  *UserPageTableTemplateSize = ALIGN_VALUE (EFI_PAGES_TO_SIZE (TotalPagesNum), PAGE_TABLE_POOL_ALIGNMENT);
+
+  SetUefiImageMemoryAttributes ((UINT64)(UINTN)PageMap, *UserPageTableTemplateSize, EFI_MEMORY_XP);
+}
 
 VOID
 EFIAPI
@@ -25,6 +105,13 @@ InitializeMsr (
   Ebx = 0;
   Edx = 0;
 
+  //
+  // Forbid global pages.
+  //
+  Cr4.UintN    = AsmReadCr4 ();
+  Cr4.Bits.PGE = 0;
+  AsmWriteCr4 (Cr4.UintN);
+
   //
   // Forbid supervisor-mode accesses to any user-mode pages.
   //
@@ -70,4 +157,6 @@ InitializeMsr (
 
   Msr = (UINT64)(UINTN)gCoreSysCallStackTop;
   AsmWriteMsr64 (MSR_IA32_SYSENTER_ESP, Msr);
+
+  gCorePageTable = AsmReadCr3 ();
 }

UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionHandlerAsm.nasm

@@ -23,16 +23,33 @@
 ;
 ; CommonExceptionHandler()
 ;
+extern ASM_PFX(mErrorCodeFlag)            ; Error code flags for exceptions
+extern ASM_PFX(mDoFarReturnFlag)          ; Do far return flag
 extern ASM_PFX(CommonExceptionHandler)
 
 SECTION .data
+ALIGN   4096
 
-extern ASM_PFX(mErrorCodeFlag)            ; Error code flags for exceptions
+global ASM_PFX(CorePageTable)
-extern ASM_PFX(mDoFarReturnFlag)          ; Do far return flag
+ASM_PFX(CorePageTable):
+  resq 1
+
+global ASM_PFX(UserPageTable)
+ASM_PFX(UserPageTable):
+  resq 1
+
+global ASM_PFX(mSwitchCr3Flag)
+ASM_PFX(mSwitchCr3Flag):
+  db 0x0
+
+ALIGN   4096
+Padding:
+  db 0x0
 
 SECTION .text
-
+ALIGN   4096
-ALIGN   8
+global ASM_PFX(ExceptionHandlerBase)
+ASM_PFX(ExceptionHandlerBase):
 
 ;
 ; exception handler stub table
@@ -88,6 +105,14 @@ HookAfterStubHeaderEnd:
 global ASM_PFX(CommonInterruptEntry)
 ASM_PFX(CommonInterruptEntry):
     cli
+    cmp     byte [ASM_PFX(mSwitchCr3Flag)], 0
+    jz      NoCr3Switch
+    mov     eax, cr3
+    mov     [ASM_PFX(UserPageTable)], eax
+    mov     eax, [ASM_PFX(CorePageTable)]
+    mov     cr3, eax
+
+NoCr3Switch:
     pop    eax
     ;
     ; All interrupt handlers are invoked through interrupt gates, so
@@ -413,8 +438,8 @@ continue:
     push    ecx
     mov     ecx, ds
     and     ecx, 3
-    pop     ecx
     jnz     ReturnToRing3
+    pop     ecx
 
     pop     dword [ebp - 8]
     pop     dword [ebp - 4]
@@ -444,11 +469,18 @@ DoReturn:
 DoIret:
     iretd
 ReturnToRing3:
+    mov     ecx, [ASM_PFX(UserPageTable)]
+    mov     cr3, ecx
+    pop     ecx
     mov     esp, ebp
     pop     ebp
     add     esp, 8
     iretd
 
+ALIGN   4096
+global ASM_PFX(ExceptionHandlerEnd)
+ASM_PFX(ExceptionHandlerEnd):
+
 ;---------------------------------------;
 ; _AsmGetTemplateAddressMap                  ;
 ;----------------------------------------------------------------------------;