ich9deblob: move descriptor functions to descriptor/struct.h

1 files changed, 88 insertions, 0 deletions

diff --git a/resources/utilities/ich9deblob/descriptor/struct.h b/resources/utilities/ich9deblob/descriptor/struct.h
index 3f2656e..710c09b 100644
--- a/resources/utilities/ich9deblob/descriptor/struct.h
+++ b/resources/utilities/ich9deblob/descriptor/struct.h
@@ -29,6 +29,9 @@
 #ifndef DESCRIPTORSTRUCT_H
 #define DESCRIPTORSTRUCT_H
 
+#include <stdio.h>
+#include <string.h>
+
 #define DESCRIPTORREGIONSIZE 0x1000 // 4 KiB
 
 // Related to the flash descriptor
@@ -60,6 +63,10 @@ struct FLMAP0 {
 	// little endian assumed
 };
 
+// ---------------------------------------------------------------------
+// Descriptor struct representing the data
+// ---------------------------------------------------------------------
+
 struct FLMAP1 {
 	unsigned char FMBA                      : 8;
 	unsigned char NM                        : 3;
@@ -225,4 +232,85 @@ struct DESCRIPTORREGIONRECORD {
 	struct OEMSECTIONRECORD oemSection;
 };
 
+// ---------------------------------------------------------------------
+// Descriptor functions
+// ---------------------------------------------------------------------
+
+// Modify the flash descriptor, to remove the ME/AMT, and disable all other regions
+// Only Flash Descriptor, Gbe and BIOS regions (BIOS region fills factoryRomSize-12k) are left.
+// Tested on ThinkPad X200 and X200S. X200T and other GM45 targets may also work.
+struct DESCRIPTORREGIONRECORD deblobbedDescriptorStructFromFactory(struct DESCRIPTORREGIONRECORD factoryDescriptorStruct, unsigned int factoryRomSize)
+{
+	struct DESCRIPTORREGIONRECORD deblobbedDescriptorStruct;
+	memcpy(&deblobbedDescriptorStruct, &factoryDescriptorStruct, DESCRIPTORREGIONSIZE);
+	
+	// Now we need to modify the descriptor so that the ME can be excluded
+	// from the final ROM image (libreboot one) after adding the modified
+	// descriptor+gbe. Refer to libreboot docs for details: docs/hcl/x200_remove_me.html
+
+	// set number of regions from 4 -> 2 (0 based, so 4 means 5 and 2
+	// means 3. We want 3 regions: descriptor, gbe and bios, in that order)
+	deblobbedDescriptorStruct.flMaps.flMap0.NR = 2;
+
+	// make descriptor writable from OS. This is that the user can run:
+	// sudo ./flashrom -p internal:laptop=force_I_want_a_brick 
+	// from the OS, without relying an an external SPI flasher, while
+	// being able to write to the descriptor region (locked by default,
+	// until making the change below):
+	deblobbedDescriptorStruct.masterAccessSection.flMstr1.fdRegionWriteAccess = 1;
+
+	// relocate BIOS region and increase size to fill image
+	deblobbedDescriptorStruct.regionSection.flReg1.BASE = 3; // 3<<FLREGIONBITSHIFT is 12KiB, which is where BIOS region is to begin (after descriptor and gbe)
+	deblobbedDescriptorStruct.regionSection.flReg1.LIMIT = ((factoryRomSize >> FLREGIONBITSHIFT) - 1);
+	// ^ for example, 8MB ROM, that's 8388608 bytes.
+	// ^ 8388608>>FLREGIONBITSHIFT (or 8388608/4096) = 2048 bytes
+	// 2048 - 1 = 2047 bytes. 
+	// This defines where the final 0x1000 (4KiB) page starts in the flash chip, because the hardware does:
+	// 2047<<FLREGIONBITSHIFT (or 2047*4096) = 8384512 bytes, or 7FF000 bytes
+	// (it can't be 0x7FFFFF because of limited number of bits)
+
+	// set ME region size to 0 - the ME is a blob, we don't want it in libreboot
+	deblobbedDescriptorStruct.regionSection.flReg2.BASE = 0x1FFF; // setting 1FFF means setting size to 0. 1FFF<<FLREGIONBITSHIFT is outside of the ROM image (8MB) size?
+	// ^ datasheet says to set this to 1FFF, but FFF was previously used and also worked.
+	deblobbedDescriptorStruct.regionSection.flReg2.LIMIT = 0;
+	// ^ 0<<FLREGIONBITSHIFT=0, so basically, the size is 0, and the base (1FFF>>FLREGIONBITSHIFT) is well outside the higher 8MB range. 
+	
+	// relocate Gbe region to begin at 4KiB (immediately after the flash descriptor)
+	deblobbedDescriptorStruct.regionSection.flReg3.BASE = 1; // 1<<FLREGIONBITSHIFT is 4096, which is where the Gbe region is to begin (after the descriptor)
+	deblobbedDescriptorStruct.regionSection.flReg3.LIMIT = 2;
+	// ^ 2<<FLREGIONBITSHIFT=8192 bytes. So we are set it to size 8KiB after the first 4KiB in the flash chip.
+
+	// set Platform region size to 0 - another blob that we don't want
+	deblobbedDescriptorStruct.regionSection.flReg4.BASE = 0x1FFF; // setting 1FFF means setting size to 0. 1FFF<<FLREGIONBITSHIFT is outside of the ROM image (8MB) size?
+	// ^ datasheet says to set this to 1FFF, but FFF was previously used and also worked.
+	deblobbedDescriptorStruct.regionSection.flReg4.LIMIT = 0;
+	// ^ 0<<FLREGIONBITSHIFT=0, so basically, the size is 0, and the base (1FFF>>FLREGIONBITSHIFT) is well outside the higher 8MB range.
+
+	// disable ME in ICHSTRAP0 - the ME is a blob, we don't want it in libreboot
+	deblobbedDescriptorStruct.ichStraps.ichStrap0.meDisable = 1;
+
+	// disable ME and TPM in MCHSTRAP0
+	deblobbedDescriptorStruct.mchStraps.mchStrap0.meDisable = 1; // ME is a blob. not wanted in libreboot.
+	deblobbedDescriptorStruct.mchStraps.mchStrap0.tpmDisable = 1; // not wanted in libreboot
+
+	// disable ME, apart from chipset bugfixes (ME region should first be re-enabled above)
+	// This is sort of like the CPU microcode updates, but for the chipset
+	// (commented out below here, since blobs go against libreboot's purpose,
+	// but may be interesting for others)
+	// deblobbedDescriptorStruct.mchStraps.mchStrap0.meAlternateDisable = 1;
+	
+	// debugging
+	printf("\nOriginal (factory.rom) Descriptor start block: %08x ; Descriptor end block: %08x\n", factoryDescriptorStruct.regionSection.flReg0.BASE << FLREGIONBITSHIFT, factoryDescriptorStruct.regionSection.flReg0.LIMIT << FLREGIONBITSHIFT);
+	printf("Original (factory.rom) BIOS start block: %08x ; BIOS end block: %08x\n", factoryDescriptorStruct.regionSection.flReg1.BASE << FLREGIONBITSHIFT, factoryDescriptorStruct.regionSection.flReg1.LIMIT << FLREGIONBITSHIFT);
+	printf("Original (factory.rom) ME start block: %08x ; ME end block: %08x\n", factoryDescriptorStruct.regionSection.flReg2.BASE << FLREGIONBITSHIFT, factoryDescriptorStruct.regionSection.flReg2.LIMIT << FLREGIONBITSHIFT);
+	printf("Original (factory.rom) GBe start block: %08x ; GBe end block: %08x\n", factoryDescriptorStruct.regionSection.flReg3.BASE << FLREGIONBITSHIFT, factoryDescriptorStruct.regionSection.flReg3.LIMIT << FLREGIONBITSHIFT);
+	
+	printf("\nRelocated (libreboot.rom) Descriptor start block: %08x ; Descriptor end block: %08x\n", deblobbedDescriptorStruct.regionSection.flReg0.BASE << FLREGIONBITSHIFT, deblobbedDescriptorStruct.regionSection.flReg0.LIMIT << FLREGIONBITSHIFT);
+	printf("Relocated (libreboot.rom) BIOS start block: %08x ; BIOS end block: %08x\n", deblobbedDescriptorStruct.regionSection.flReg1.BASE << FLREGIONBITSHIFT, deblobbedDescriptorStruct.regionSection.flReg1.LIMIT << FLREGIONBITSHIFT);
+	printf("Relocated (libreboot.rom) ME start block: %08x ; ME end block: %08x\n", deblobbedDescriptorStruct.regionSection.flReg2.BASE << FLREGIONBITSHIFT, deblobbedDescriptorStruct.regionSection.flReg2.LIMIT << FLREGIONBITSHIFT);
+	printf("Relocated (libreboot.rom) GBe start block: %08x ; GBe end block: %08x\n", deblobbedDescriptorStruct.regionSection.flReg3.BASE << FLREGIONBITSHIFT, deblobbedDescriptorStruct.regionSection.flReg3.LIMIT << FLREGIONBITSHIFT);
+	
+	return deblobbedDescriptorStruct;
+}
+
 #endif