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/*
* ich9deblob.c
* This file is part of the ich9deblob utility from the libreboot project
*
* Purpose: disable and remove the ME from ich9m/gm45 machines in coreboot.
*
* Copyright (C) 2014 Steve Shenton <sgsit@libreboot.org>
* Francis Rowe <info@gluglug.org.uk>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Read a factory.rom dump (ich9m/gm45 machines) and
* modify the flash descriptor to remove all regions except descriptor,
* Gbe and BIOS. Set BIOS region to full size of the ROM image (after
* the flash descriptor and gbe). Basically, deblob the descriptor.
*
* This will will generate a concatenated descriptor+gbe dump suitable
* for use in libreboot. Currently tested: ThinkPad X200 (coreboot/libreboot)
*/
// See docs/hcl/x200_remove_me.html for info plus links to datasheet (also linked below)
// Info about flash descriptor (read page 850 onwards):
// * http://www.intel.co.uk/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf
// Info about Gbe region (read whole datasheet):
// * http://www.intel.co.uk/content/dam/doc/application-note/i-o-controller-hub-9m-82567lf-lm-v-nvm-map-appl-note.pdf
// * https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums
#include <stdio.h>
#include <string.h>
#include "descriptor/struct.h" // structs describing what's in the descriptor region
#include "gbe/gbe.h" // structs describing what's in the gbe region, plus functions that use them
#include "x86compatibility.c" // compatibility checks. this utility is not portable yet.
int main(int argc, char *argv[])
{
// descriptor region. Will have an actual descriptor struct mapped to it (from the factory.rom dump)
// and then it will be modified (deblobbed) to remove the ME/AMT
char factoryDescriptorBuffer[DESCRIPTORREGIONSIZE];
struct DESCRIPTORREGIONRECORD factoryDescriptorStruct;
char deblobbedDescriptorBuffer[DESCRIPTORREGIONSIZE];
struct DESCRIPTORREGIONRECORD deblobbedDescriptorStruct;
// gbe region. Well have actual gbe buffer mapped to it (from the factory.rom dump)
// and then it will be modified to correct the main region
char factoryGbeBuffer8k[GBEREGIONSIZE];
struct GBEREGIONRECORD_8K factoryGbeStruct8k;
char deblobbedGbeBuffer8k[GBEREGIONSIZE];
struct GBEREGIONRECORD_8K deblobbedGbeStruct8k;
// Used to store the location of the Gbe
// region inside the factory.rom image.
unsigned int factoryGbeRegionStart;
// names of the files that this utility will handle
char* factoryRomFilename = "factory.rom"; // user-supplied factory.bin dump (original firmware)
char* deblobbedDescriptorFilename = "deblobbed_descriptor.bin"; // descriptor+gbe: to be dd'd to beginning of a libreboot image
// Used when reading the factory.rom to extract descriptor/gbe regions
unsigned int bufferLength;
// For storing the size of the factory.rom dump in bytes
unsigned int factoryRomSize;
// -----------------------------------------------------------------------------------------------
// Compatibility checks. This version of ich9deblob is not yet porable.
if (systemOrCompilerIncompatible(factoryDescriptorStruct, factoryGbeStruct8k)) return 1;
// -----------------------------------------------------------------------------------------------
// Open factory.rom, needed for extracting descriptor and gbe
// -----------------------------------------------
FILE* fileStream = NULL;
fileStream = fopen(factoryRomFilename, "rb"); // open factory.rom
if (NULL == fileStream)
{
printf("\nerror: could not open factory.rom\n");
return 1;
}
printf("\nfactory.rom opened successfully\n");
// -----------------------------------------------
// Get the descriptor region dump from the factory.rom
// (goes in factoryDescriptorBuffer variable)
bufferLength = fread(factoryDescriptorBuffer, sizeof(char), DESCRIPTORREGIONSIZE, fileStream);
if (DESCRIPTORREGIONSIZE != bufferLength) //
{
printf("\nerror: could not read descriptor from factory.rom (%i) bytes read\n", bufferLength);
return 1;
}
printf("\ndescriptor region read successfully\n");
// copy descriptor buffer into descriptor struct memory
// factoryDescriptorStruct is an instance of a struct that actually
// defines the locations of all these variables in the descriptor,
// as defined in the datasheets. This allows us to map the extracted
// descriptor over the struct so that it can then be modified
// for libreboot's purpose
memcpy(&factoryDescriptorStruct, &factoryDescriptorBuffer, DESCRIPTORREGIONSIZE);
// ^ the above is just for reference if needed. The modifications will be made here:
memcpy(&deblobbedDescriptorStruct, &factoryDescriptorBuffer, DESCRIPTORREGIONSIZE);
// -----------------------------------------------------------------------------------------------
// Get the gbe region dump from the factory.rom
// get original GBe region location
// (it will be moved to the beginning of the flash, after the descriptor region)
// note for example, factoryGbeRegionStart is set to <<FLREGIONBITSHIFT of actual address (in C). this is how the addresses
// are stored in the descriptor.
factoryGbeRegionStart = factoryDescriptorStruct.regionSection.flReg3.BASE << FLREGIONBITSHIFT;
// Set offset so that we can read the data from
// the gbe region
fseek(fileStream, factoryGbeRegionStart, SEEK_SET);
// Read the gbe data from the factory.rom and put it in factoryGbeBuffer8k
bufferLength = fread(factoryGbeBuffer8k, sizeof(char), GBEREGIONSIZE, fileStream);
if (GBEREGIONSIZE != bufferLength)
{
printf("\nerror: could not read GBe region from factory.rom (%i) bytes read\n", bufferLength);
return 1;
}
printf("\ngbe (8KiB) region read successfully\n");
// copy gbe buffer into gbe struct memory
// factoryGbeStruct8k is an instance of a struct that actually
// defines the locations of all these variables in the gbe,
// as defined in the datasheets. This allows us to map the extracted
// gbe over the struct so that it can then be modified
// for libreboot's purpose
memcpy(&factoryGbeStruct8k, &factoryGbeBuffer8k, GBEREGIONSIZE);
// the original factoryGbeStruct8k is only reference. Changes go here:
memcpy(&deblobbedGbeStruct8k, &factoryGbeBuffer8k, GBEREGIONSIZE);
// -----------------------------------------------------------------------------------------------
// Get size of ROM image
// This is needed for relocating the BIOS region (per descriptor)
fseek(fileStream, 0L, SEEK_END);
factoryRomSize = ftell(fileStream);
printf("\nfactory.rom size: [%i] bytes\n", factoryRomSize);
fclose(fileStream);
// -----------------------------------------------------------------------------------------------
// Disable the ME and Platform regions. Put Gbe at the beginning (after descriptor).
// Also, extend the BIOS region to fill the ROM image (after descriptor+gbe).
deblobbedDescriptorStruct = deblobbedDescriptorStructFromFactory(factoryDescriptorStruct, factoryRomSize);
// ----------------------------------------------------------------------------------------------------------------
// Modify the Gbe descriptor (see function for details)
deblobbedGbeStruct8k = deblobbedGbeStructFromFactory(factoryGbeStruct8k);
// ----------------------------------------------------------------------------------------------------------------
// Convert the deblobbed descriptor and gbe back to byte arrays, so that they
// can more easily be written to files:
// deblobbed descriptor region
memcpy(&deblobbedDescriptorBuffer, &deblobbedDescriptorStruct, DESCRIPTORREGIONSIZE); // descriptor
memcpy(&deblobbedGbeBuffer8k, &deblobbedGbeStruct8k, GBEREGIONSIZE); // gbe
// delete old file before continuing
remove(deblobbedDescriptorFilename);
// open new file for writing the deblobbed descriptor+gbe
fileStream = fopen(deblobbedDescriptorFilename, "ab");
// write the descriptor region into the first part
if (DESCRIPTORREGIONSIZE != fwrite(deblobbedDescriptorBuffer, sizeof(char), DESCRIPTORREGIONSIZE, fileStream))
{
printf("\nerror: writing descriptor region failed\n");
return 1;
}
// add gbe to the end of the file
if (GBEREGIONSIZE != fwrite(deblobbedGbeBuffer8k, sizeof(char), GBEREGIONSIZE, fileStream))
{
printf("\nerror: writing GBe region failed\n");
return 1;
}
fclose(fileStream);
printf("\ndeblobbed descriptor successfully created: deblobbed_descriptor.bin \n");
// -------------------------------------------------------------------------------------
printf("\nNow do: dd if=deblobbed_descriptor.bin of=libreboot.rom bs=1 count=12k conv=notrunc");
printf("\n(in other words, add the modified descriptor+gbe to your ROM image)\n");
return 0;
}
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