From 7ffd20ca3fc1e9d436683b2e34c4e2e47fac2c7f Mon Sep 17 00:00:00 2001 From: Francis Rowe Date: Tue, 23 Dec 2014 11:37:17 -0500 Subject: ich9deblob: move gbe functions to gbe/struct.h --- diff --git a/resources/utilities/ich9deblob/gbe/struct.h b/resources/utilities/ich9deblob/gbe/struct.h index 294ff30..cbc2635 100644 --- a/resources/utilities/ich9deblob/gbe/struct.h +++ b/resources/utilities/ich9deblob/gbe/struct.h @@ -29,12 +29,19 @@ #ifndef GBESTRUCT_H #define GBESTRUCT_H +#include +#include + #define GBEREGIONSIZE 0x2000 // 8 KiB // These will have a modified descriptor+gbe based on what's in the factory.rom // These will be joined into a single 12KiB buffer (descriptor, then gbe) and saved to a file // NOTE: The GBE region of 8K is actually 2x 4K regions in a single region; both 4K blocks can be identical (and by default, are) // The 2nd one is a "backup", but we don't know when it's used. perhaps it's used when the checksum on the first one does not match? +// --------------------------------------------------------------------- +// Gbe struct representing the data +// --------------------------------------------------------------------- + struct GBEREGIONRECORD_4K { unsigned char macAddress[6]; // 0x03 words, or 0x06 bytes unsigned char otherStuff[120]; // 0x3c words, or 0x7E bytes @@ -52,4 +59,70 @@ struct GBEREGIONRECORD_8K { // lenovobios's gbe region) and then copy to main }; +// --------------------------------------------------------------------- +// Gbe functions +// --------------------------------------------------------------------- + +// Read a 16-bit unsigned int from a supplied region buffer +unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData) +{ + return *((unsigned short*)(regionData + (index * 2))); +} + +// checksum calculation for 8k gbe region (algorithm based on datasheet) +// also works for 4k buffers, so long as isBackup remains false +unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, char isBackup) +{ + int i; + + unsigned short regionWord; // store words here for adding to checksum + unsigned short checksum = 0; // this gbe's checksum + unsigned short offset = 0; // in bytes, from the start of the gbe region. + + // if isBackup is true, use 2nd gbe region ("backup" region) + if (isBackup) offset = 0x1000>>1; // this function uses *word* not *byte* indexes. + + for (i = 0; i < 0x3F; i++) { + regionWord = gbeGetRegionWordFrom8kBuffer(i+offset, regionData); + checksum += regionWord; + } + checksum = desiredValue - checksum; + return checksum; +} + +// checksum calculation for 4k gbe struct (algorithm based on datasheet) +unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue) +{ + char gbeBuffer4k[GBEREGIONSIZE>>1]; + memcpy(&gbeBuffer4k, &gbeStruct4k, GBEREGIONSIZE>>1); + return gbeGetChecksumFrom8kBuffer(gbeBuffer4k, desiredValue, 0); +} + +// modify the gbe region extracted from a factory.rom dump +struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k) +{ + // Correct the main gbe region. By default, the X200 (as shipped from Lenovo) comes + // with a broken main gbe region, where the backup gbe region is used instead. Modify + // the descriptor so that the main region is usable. + + struct GBEREGIONRECORD_8K deblobbedGbeStruct8k; + memcpy(&deblobbedGbeStruct8k, &factoryGbeStruct8k, GBEREGIONSIZE); + + deblobbedGbeStruct8k.backup.checkSum = gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, 0xBABA); + memcpy(&deblobbedGbeStruct8k.main, &deblobbedGbeStruct8k.backup, GBEREGIONSIZE>>1); + + // Debugging: + // calculate the 0x3F'th 16-bit uint to make the desired final checksum for GBe + // observed checksum matches (from X200 factory.rom dumps) on main: 0x3ABA 0x34BA 0x40BA. spec defined as 0xBABA. + // X200 ships with a broken main gbe region by default (invalid checksum, and more) + // The "backup" gbe regions on these machines are correct, though, and is what the machines default to + // For libreboot's purpose, we can do much better than that by fixing the main one... below is only debugging + printf("\nfactory Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.main, 0xBABA), factoryGbeStruct8k.main.checkSum); + printf("factory Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.backup, 0xBABA), factoryGbeStruct8k.backup.checkSum); + printf("\ndeblobbed Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.main, 0xBABA), deblobbedGbeStruct8k.main.checkSum); + printf("deblobbed Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, 0xBABA), deblobbedGbeStruct8k.backup.checkSum); + + return deblobbedGbeStruct8k; +} + #endif diff --git a/resources/utilities/ich9deblob/ich9deblob.c b/resources/utilities/ich9deblob/ich9deblob.c index 2081bc4..e308312 100644 --- a/resources/utilities/ich9deblob/ich9deblob.c +++ b/resources/utilities/ich9deblob/ich9deblob.c @@ -46,11 +46,7 @@ #include "gbe/struct.h" // structs describing what's in the gbe region #include "x86compatibility.c" // compatibility checks. this utility is not portable yet. -unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue); -unsigned short gbeGetChecksumFrom8kBuffer(char* buffer, unsigned short desiredValue, char isBackup); // for GBe region (checksum calculation) -unsigned short gbeGetRegionWordFrom8kBuffer(int i, char* buffer); // used for getting each word needed to calculate said checksum struct DESCRIPTORREGIONRECORD deblobbedDescriptorStructFromFactory(struct DESCRIPTORREGIONRECORD factoryDescriptorStruct, unsigned int factoryRomSize); -struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k); int main(int argc, char *argv[]) { @@ -292,67 +288,3 @@ struct DESCRIPTORREGIONRECORD deblobbedDescriptorStructFromFactory(struct DESCRI return deblobbedDescriptorStruct; } - -// --------------------------------------------------------------------- -// Gbe functions -// --------------------------------------------------------------------- - -struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k) -{ - // Correct the main gbe region. By default, the X200 (as shipped from Lenovo) comes - // with a broken main gbe region, where the backup gbe region is used instead. Modify - // the descriptor so that the main region is usable. - - struct GBEREGIONRECORD_8K deblobbedGbeStruct8k; - memcpy(&deblobbedGbeStruct8k, &factoryGbeStruct8k, GBEREGIONSIZE); - - deblobbedGbeStruct8k.backup.checkSum = gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, 0xBABA); - memcpy(&deblobbedGbeStruct8k.main, &deblobbedGbeStruct8k.backup, GBEREGIONSIZE>>1); - - // Debugging: - // calculate the 0x3F'th 16-bit uint to make the desired final checksum for GBe - // observed checksum matches (from X200 factory.rom dumps) on main: 0x3ABA 0x34BA 0x40BA. spec defined as 0xBABA. - // X200 ships with a broken main gbe region by default (invalid checksum, and more) - // The "backup" gbe regions on these machines are correct, though, and is what the machines default to - // For libreboot's purpose, we can do much better than that by fixing the main one... below is only debugging - printf("\nfactory Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.main, 0xBABA), factoryGbeStruct8k.main.checkSum); - printf("factory Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.backup, 0xBABA), factoryGbeStruct8k.backup.checkSum); - printf("\ndeblobbed Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.main, 0xBABA), deblobbedGbeStruct8k.main.checkSum); - printf("deblobbed Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, 0xBABA), deblobbedGbeStruct8k.backup.checkSum); - - return deblobbedGbeStruct8k; -} - -// checksum calculation for 4k gbe struct (algorithm based on datasheet) -unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue) -{ - char gbeBuffer4k[GBEREGIONSIZE>>1]; - memcpy(&gbeBuffer4k, &gbeStruct4k, GBEREGIONSIZE>>1); - return gbeGetChecksumFrom8kBuffer(gbeBuffer4k, desiredValue, 0); -} -// checksum calculation for 8k gbe region (algorithm based on datasheet) -// also works for 4k buffers, so long as isBackup remains false -unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, char isBackup) -{ - int i; - - unsigned short regionWord; // store words here for adding to checksum - unsigned short checksum = 0; // this gbe's checksum - unsigned short offset = 0; // in bytes, from the start of the gbe region. - - // if isBackup is true, use 2nd gbe region ("backup" region) - if (isBackup) offset = 0x1000>>1; // this function uses *word* not *byte* indexes. - - for (i = 0; i < 0x3F; i++) { - regionWord = gbeGetRegionWordFrom8kBuffer(i+offset, regionData); - checksum += regionWord; - } - checksum = desiredValue - checksum; - return checksum; -} -// Read a 16-bit unsigned int from a supplied region buffer -unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData) -{ - return *((unsigned short*)(regionData + (index * 2))); -} - -- cgit v0.9.1