/** @file
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PCH BIOS Write Protect Driver.
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Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "PchInitSmm.h"
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#include <Register/PchRegs.h>
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#include <Register/PchRegsLpc.h>
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#include <Register/SpiRegs.h>
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#include <Library/SpiAccessPrivateLib.h>
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#include <Library/PchPciBdfLib.h>
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//
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// Global variables
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//
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GLOBAL_REMOVE_IF_UNREFERENCED PCH_TCO_SMI_DISPATCH_PROTOCOL *mPchTcoSmiDispatchProtocol;
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GLOBAL_REMOVE_IF_UNREFERENCED PCH_ESPI_SMI_DISPATCH_PROTOCOL *mEspiSmmDispatchProtocol;
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GLOBAL_REMOVE_IF_UNREFERENCED UINT64 mLpcRegBase;
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/**
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This hardware SMI handler will be run every time the BIOS Write Enable bit is set.
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@param[in] DispatchHandle Not used
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**/
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VOID
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EFIAPI
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PchSpiBiosWpCallback (
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IN EFI_HANDLE DispatchHandle
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)
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{
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SpiClearBiosWriteProtectDisable ();
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}
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/**
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This hardware SMI handler will be run every time the BIOS Write Enable bit is set.
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@param[in] DispatchHandle Not used
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**/
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VOID
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EFIAPI
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PchLpcBiosWpCallback (
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IN EFI_HANDLE DispatchHandle
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)
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{
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//
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// Disable BIOSWE bit to protect BIOS
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//
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PciSegmentAnd8 ((UINTN) (mLpcRegBase + R_LPC_CFG_BC), (UINT8) ~B_LPC_CFG_BC_WPD);
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}
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/**
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Entry point for Pch Bios Write Protect driver.
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@param[in] ImageHandle Image handle of this driver.
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@param[in] SystemTable Global system service table.
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@retval EFI_SUCCESS Initialization complete.
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**/
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EFI_STATUS
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EFIAPI
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InstallPchBiosWriteProtect (
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IN EFI_HANDLE ImageHandle,
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IN EFI_SYSTEM_TABLE *SystemTable
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)
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{
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EFI_STATUS Status;
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EFI_HANDLE Handle;
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DEBUG ((DEBUG_INFO, "InstallPchBiosWriteProtect()\n"));
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if (mPchConfigHob->LockDown.BiosLock != TRUE) {
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return EFI_SUCCESS;
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}
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mLpcRegBase = LpcPciCfgBase ();
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DEBUG ((DEBUG_INFO, "Installing BIOS Write Protect SMI handler\n"));
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//
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// Get the PCH TCO SMM dispatch protocol
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//
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mPchTcoSmiDispatchProtocol = NULL;
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Status = gSmst->SmmLocateProtocol (&gPchTcoSmiDispatchProtocolGuid, NULL, (VOID **) &mPchTcoSmiDispatchProtocol);
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ASSERT_EFI_ERROR (Status);
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//
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// Always register an SPI BiosWp callback function to handle TCO BIOSWR SMI
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// NOTE: No matter the BIOS resides behind SPI or not, it needs to handle the SPI BIOS WP SMI
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// to avoid SMI deadloop on SPI WPD write.
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//
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Handle = NULL;
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Status = mPchTcoSmiDispatchProtocol->SpiBiosWpRegister (
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mPchTcoSmiDispatchProtocol,
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PchSpiBiosWpCallback,
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&Handle
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);
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ASSERT_EFI_ERROR (Status);
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//
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// Always register an LPC/eSPI BiosWp callback function to handle TCO BIOSWR SMI
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// NOTE: No matter the BIOS resides behind LPC/eSPI or not, it needs to handle the BIOS WP SMI
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// to avoid SMI deadloop on LPC/eSPI WPD write.
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//
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if (IsEspiEnabled ()) {
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//
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// Get the PCH ESPI SMM dispatch protocol
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//
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mEspiSmmDispatchProtocol = NULL;
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Status = gSmst->SmmLocateProtocol (&gPchEspiSmiDispatchProtocolGuid, NULL, (VOID **) &mEspiSmmDispatchProtocol);
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ASSERT_EFI_ERROR (Status);
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//
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// Register an ESpiBiosWp callback function to handle BIOSWR SMI
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//
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Handle = NULL;
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Status = mEspiSmmDispatchProtocol->BiosWrProtectRegister (
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mEspiSmmDispatchProtocol,
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PchLpcBiosWpCallback,
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&Handle
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);
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ASSERT_EFI_ERROR (Status);
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} else {
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//
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// Register an LPC BiosWp callback function to handle TCO BIOSWR SMI
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//
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Handle = NULL;
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Status = mPchTcoSmiDispatchProtocol->LpcBiosWpRegister (
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mPchTcoSmiDispatchProtocol,
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PchLpcBiosWpCallback,
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&Handle
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);
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ASSERT_EFI_ERROR (Status);
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}
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return EFI_SUCCESS;
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}
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