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/** @file
Provides services to access SMRAM Save State Map
Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
Copyright (C) 2023 Advanced Micro Devices, Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiSmm.h>
#include <Library/SmmCpuFeaturesLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/SmmServicesTableLib.h>
#include <Library/DebugLib.h>
#include "PiSmmCpuDxeSmm.h"
typedef struct {
UINT64 Signature; // Offset 0x00
UINT16 Reserved1; // Offset 0x08
UINT16 Reserved2; // Offset 0x0A
UINT16 Reserved3; // Offset 0x0C
UINT16 SmmCs; // Offset 0x0E
UINT16 SmmDs; // Offset 0x10
UINT16 SmmSs; // Offset 0x12
UINT16 SmmOtherSegment; // Offset 0x14
UINT16 Reserved4; // Offset 0x16
UINT64 Reserved5; // Offset 0x18
UINT64 Reserved6; // Offset 0x20
UINT64 Reserved7; // Offset 0x28
UINT64 SmmGdtPtr; // Offset 0x30
UINT32 SmmGdtSize; // Offset 0x38
UINT32 Reserved8; // Offset 0x3C
UINT64 Reserved9; // Offset 0x40
UINT64 Reserved10; // Offset 0x48
UINT16 Reserved11; // Offset 0x50
UINT16 Reserved12; // Offset 0x52
UINT32 Reserved13; // Offset 0x54
UINT64 Reserved14; // Offset 0x58
} PROCESSOR_SMM_DESCRIPTOR;
extern CONST PROCESSOR_SMM_DESCRIPTOR gcPsd;
//
// EFER register LMA bit
//
#define LMA BIT10
///
/// Variables from SMI Handler
///
X86_ASSEMBLY_PATCH_LABEL gPatchSmbase;
X86_ASSEMBLY_PATCH_LABEL gPatchSmiStack;
X86_ASSEMBLY_PATCH_LABEL gPatchSmiCr3;
extern volatile UINT8 gcSmiHandlerTemplate[];
extern CONST UINT16 gcSmiHandlerSize;
//
// Variables used by SMI Handler
//
IA32_DESCRIPTOR gSmiHandlerIdtr;
///
/// The mode of the CPU at the time an SMI occurs
///
UINT8 mSmmSaveStateRegisterLma;
/**
Hook the code executed immediately after an RSM instruction on the currently
executing CPU. The mode of code executed immediately after RSM must be
detected, and the appropriate hook must be selected. Always clear the auto
HALT restart flag if it is set.
@param[in] CpuIndex The processor index for the currently
executing CPU.
@param[in] CpuState Pointer to SMRAM Save State Map for the
currently executing CPU.
@param[in] NewInstructionPointer32 Instruction pointer to use if resuming to
32-bit mode from 64-bit SMM.
@param[in] NewInstructionPointer Instruction pointer to use if resuming to
same mode as SMM.
@retval The value of the original instruction pointer before it was hooked.
**/
UINT64
EFIAPI
HookReturnFromSmm (
IN UINTN CpuIndex,
SMRAM_SAVE_STATE_MAP *CpuState,
UINT64 NewInstructionPointer32,
UINT64 NewInstructionPointer
)
{
UINT64 OriginalInstructionPointer;
OriginalInstructionPointer = SmmCpuFeaturesHookReturnFromSmm (
CpuIndex,
CpuState,
NewInstructionPointer32,
NewInstructionPointer
);
if (OriginalInstructionPointer != 0) {
return OriginalInstructionPointer;
}
if (mSmmSaveStateRegisterLma == EFI_SMM_SAVE_STATE_REGISTER_LMA_32BIT) {
OriginalInstructionPointer = (UINT64)CpuState->x86._EIP;
CpuState->x86._EIP = (UINT32)NewInstructionPointer;
//
// Clear the auto HALT restart flag so the RSM instruction returns
// program control to the instruction following the HLT instruction.
//
if ((CpuState->x86.AutoHALTRestart & BIT0) != 0) {
CpuState->x86.AutoHALTRestart &= ~BIT0;
}
} else {
OriginalInstructionPointer = CpuState->x64._RIP;
if ((CpuState->x64.IA32_EFER & LMA) == 0) {
CpuState->x64._RIP = (UINT32)NewInstructionPointer32;
} else {
CpuState->x64._RIP = (UINT32)NewInstructionPointer;
}
//
// Clear the auto HALT restart flag so the RSM instruction returns
// program control to the instruction following the HLT instruction.
//
if ((CpuState->x64.AutoHALTRestart & BIT0) != 0) {
CpuState->x64.AutoHALTRestart &= ~BIT0;
}
}
return OriginalInstructionPointer;
}
/**
Get the size of the SMI Handler in bytes.
@retval The size, in bytes, of the SMI Handler.
**/
UINTN
EFIAPI
GetSmiHandlerSize (
VOID
)
{
UINTN Size;
Size = SmmCpuFeaturesGetSmiHandlerSize ();
if (Size != 0) {
return Size;
}
return gcSmiHandlerSize;
}
/**
Install the SMI handler for the CPU specified by CpuIndex. This function
is called by the CPU that was elected as monarch during System Management
Mode initialization.
@param[in] CpuIndex The index of the CPU to install the custom SMI handler.
The value must be between 0 and the NumberOfCpus field
in the System Management System Table (SMST).
@param[in] SmBase The SMBASE address for the CPU specified by CpuIndex.
@param[in] SmiStack The stack to use when an SMI is processed by the
the CPU specified by CpuIndex.
@param[in] StackSize The size, in bytes, if the stack used when an SMI is
processed by the CPU specified by CpuIndex.
@param[in] GdtBase The base address of the GDT to use when an SMI is
processed by the CPU specified by CpuIndex.
@param[in] GdtSize The size, in bytes, of the GDT used when an SMI is
processed by the CPU specified by CpuIndex.
@param[in] IdtBase The base address of the IDT to use when an SMI is
processed by the CPU specified by CpuIndex.
@param[in] IdtSize The size, in bytes, of the IDT used when an SMI is
processed by the CPU specified by CpuIndex.
@param[in] Cr3 The base address of the page tables to use when an SMI
is processed by the CPU specified by CpuIndex.
**/
VOID
EFIAPI
InstallSmiHandler (
IN UINTN CpuIndex,
IN UINT32 SmBase,
IN VOID *SmiStack,
IN UINTN StackSize,
IN UINTN GdtBase,
IN UINTN GdtSize,
IN UINTN IdtBase,
IN UINTN IdtSize,
IN UINT32 Cr3
)
{
PROCESSOR_SMM_DESCRIPTOR *Psd;
UINT32 CpuSmiStack;
//
// Initialize PROCESSOR_SMM_DESCRIPTOR
//
Psd = (PROCESSOR_SMM_DESCRIPTOR *)(VOID *)((UINTN)SmBase + SMM_PSD_OFFSET);
CopyMem (Psd, &gcPsd, sizeof (gcPsd));
Psd->SmmGdtPtr = (UINT64)GdtBase;
Psd->SmmGdtSize = (UINT32)GdtSize;
if (SmmCpuFeaturesGetSmiHandlerSize () != 0) {
//
// Install SMI handler provided by library
//
SmmCpuFeaturesInstallSmiHandler (
CpuIndex,
SmBase,
SmiStack,
StackSize,
GdtBase,
GdtSize,
IdtBase,
IdtSize,
Cr3
);
return;
}
InitShadowStack (CpuIndex, (VOID *)((UINTN)SmiStack + StackSize));
//
// Initialize values in template before copy
//
CpuSmiStack = (UINT32)((UINTN)SmiStack + StackSize - sizeof (UINTN));
PatchInstructionX86 (gPatchSmiStack, CpuSmiStack, 4);
PatchInstructionX86 (gPatchSmiCr3, Cr3, 4);
PatchInstructionX86 (gPatchSmbase, SmBase, 4);
gSmiHandlerIdtr.Base = IdtBase;
gSmiHandlerIdtr.Limit = (UINT16)(IdtSize - 1);
//
// Set the value at the top of the CPU stack to the CPU Index
//
*(UINTN *)(UINTN)CpuSmiStack = CpuIndex;
//
// Copy template to CPU specific SMI handler location
//
CopyMem (
(VOID *)((UINTN)SmBase + SMM_HANDLER_OFFSET),
(VOID *)gcSmiHandlerTemplate,
gcSmiHandlerSize
);
}
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