Replace dldiFixDriverAddresses in dldiLoadFromBin

arm9/source/driveOperations.cpp

@@ -198,13 +198,142 @@ void sdUnmount(void) {
 	sdMounted = false;
 }
 
+typedef signed int addr_t;
+typedef unsigned char data_t;
+
+#define FIX_ALL	0x01
+#define FIX_GLUE	0x02
+#define FIX_GOT	0x04
+#define FIX_BSS	0x08
+
+enum DldiOffsets {
+	DO_magicString = 0x00,			// "\xED\xA5\x8D\xBF Chishm"
+	DO_magicToken = 0x00,			// 0xBF8DA5ED
+	DO_magicShortString = 0x04,		// " Chishm"
+	DO_version = 0x0C,
+	DO_driverSize = 0x0D,
+	DO_fixSections = 0x0E,
+	DO_allocatedSpace = 0x0F,
+
+	DO_friendlyName = 0x10,
+
+	DO_text_start = 0x40,			// Data start
+	DO_data_end = 0x44,				// Data end
+	DO_glue_start = 0x48,			// Interworking glue start	-- Needs address fixing
+	DO_glue_end = 0x4C,				// Interworking glue end
+	DO_got_start = 0x50,			// GOT start					-- Needs address fixing
+	DO_got_end = 0x54,				// GOT end
+	DO_bss_start = 0x58,			// bss start					-- Needs setting to zero
+	DO_bss_end = 0x5C,				// bss end
+
+	// IO_INTERFACE data
+	DO_ioType = 0x60,
+	DO_features = 0x64,
+	DO_startup = 0x68,	
+	DO_isInserted = 0x6C,	
+	DO_readSectors = 0x70,	
+	DO_writeSectors = 0x74,
+	DO_clearStatus = 0x78,
+	DO_shutdown = 0x7C,
+	DO_code = 0x80
+};
+
+static addr_t readAddr (data_t *mem, addr_t offset) {
+	return ((addr_t*)mem)[offset/sizeof(addr_t)];
+}
+
+static void writeAddr (data_t *mem, addr_t offset, addr_t value) {
+	((addr_t*)mem)[offset/sizeof(addr_t)] = value;
+}
+
+TWL_CODE static void dldiRelocateBinary (data_t *binData, size_t dldiFileSize)
+{
+	addr_t memOffset;			// Offset of DLDI after the file is loaded into memory
+	addr_t relocationOffset;	// Value added to all offsets within the patch to fix it properly
+	addr_t ddmemOffset;			// Original offset used in the DLDI file
+	addr_t ddmemStart;			// Start of range that offsets can be in the DLDI file
+	addr_t ddmemEnd;			// End of range that offsets can be in the DLDI file
+	addr_t ddmemSize;			// Size of range that offsets can be in the DLDI file
+
+	addr_t addrIter;
+
+	data_t *pDH = binData;
+	data_t *pAH = (data_t*)(io_dldi_data);
+
+	// size_t dldiFileSize = 1 << pDH[DO_driverSize];
+
+	memOffset = readAddr (pAH, DO_text_start);
+	if (memOffset == 0) {
+			memOffset = readAddr (pAH, DO_startup) - DO_code;
+	}
+	ddmemOffset = readAddr (pDH, DO_text_start);
+	relocationOffset = memOffset - ddmemOffset;
+
+	ddmemStart = readAddr (pDH, DO_text_start);
+	ddmemSize = (1 << pDH[DO_driverSize]);
+	ddmemEnd = ddmemStart + ddmemSize;
+
+	// Remember how much space is actually reserved
+	pDH[DO_allocatedSpace] = pAH[DO_allocatedSpace];
+	// Copy the DLDI patch into the application
+	tonccpy (pAH, pDH, dldiFileSize);
+
+	// Fix the section pointers in the header
+	writeAddr (pAH, DO_text_start, readAddr (pAH, DO_text_start) + relocationOffset);
+	writeAddr (pAH, DO_data_end, readAddr (pAH, DO_data_end) + relocationOffset);
+	writeAddr (pAH, DO_glue_start, readAddr (pAH, DO_glue_start) + relocationOffset);
+	writeAddr (pAH, DO_glue_end, readAddr (pAH, DO_glue_end) + relocationOffset);
+	writeAddr (pAH, DO_got_start, readAddr (pAH, DO_got_start) + relocationOffset);
+	writeAddr (pAH, DO_got_end, readAddr (pAH, DO_got_end) + relocationOffset);
+	writeAddr (pAH, DO_bss_start, readAddr (pAH, DO_bss_start) + relocationOffset);
+	writeAddr (pAH, DO_bss_end, readAddr (pAH, DO_bss_end) + relocationOffset);
+	// Fix the function pointers in the header
+	writeAddr (pAH, DO_startup, readAddr (pAH, DO_startup) + relocationOffset);
+	writeAddr (pAH, DO_isInserted, readAddr (pAH, DO_isInserted) + relocationOffset);
+	writeAddr (pAH, DO_readSectors, readAddr (pAH, DO_readSectors) + relocationOffset);
+	writeAddr (pAH, DO_writeSectors, readAddr (pAH, DO_writeSectors) + relocationOffset);
+	writeAddr (pAH, DO_clearStatus, readAddr (pAH, DO_clearStatus) + relocationOffset);
+	writeAddr (pAH, DO_shutdown, readAddr (pAH, DO_shutdown) + relocationOffset);
+
+	if (pDH[DO_fixSections] & FIX_ALL) { 
+		// Search through and fix pointers within the data section of the file
+		for (addrIter = (readAddr(pDH, DO_text_start) - ddmemStart); addrIter < (readAddr(pDH, DO_data_end) - ddmemStart); addrIter++) {
+			if ((ddmemStart <= readAddr(pAH, addrIter)) && (readAddr(pAH, addrIter) < ddmemEnd)) {
+				writeAddr (pAH, addrIter, readAddr(pAH, addrIter) + relocationOffset);
+			}
+		}
+	}
+
+	if (pDH[DO_fixSections] & FIX_GLUE) { 
+		// Search through and fix pointers within the glue section of the file
+		for (addrIter = (readAddr(pDH, DO_glue_start) - ddmemStart); addrIter < (readAddr(pDH, DO_glue_end) - ddmemStart); addrIter++) {
+			if ((ddmemStart <= readAddr(pAH, addrIter)) && (readAddr(pAH, addrIter) < ddmemEnd)) {
+				writeAddr (pAH, addrIter, readAddr(pAH, addrIter) + relocationOffset);
+			}
+		}
+	}
+
+	if (pDH[DO_fixSections] & FIX_GOT) { 
+		// Search through and fix pointers within the Global Offset Table section of the file
+		for (addrIter = (readAddr(pDH, DO_got_start) - ddmemStart); addrIter < (readAddr(pDH, DO_got_end) - ddmemStart); addrIter++) {
+			if ((ddmemStart <= readAddr(pAH, addrIter)) && (readAddr(pAH, addrIter) < ddmemEnd)) {
+				writeAddr (pAH, addrIter, readAddr(pAH, addrIter) + relocationOffset);
+			}
+		}
+	}
+
+	if (pDH[DO_fixSections] & FIX_BSS) { 
+		// Initialise the BSS to 0
+		toncset (&pAH[readAddr(pDH, DO_bss_start) - ddmemStart] , 0, readAddr(pDH, DO_bss_end) - readAddr(pDH, DO_bss_start));
+	}
+}
+
 TWL_CODE void dldiLoadFromBin (const u8 dldiAddr[]) {
 	// Check that it is a valid DLDI
 	if (!dldiIsValid ((DLDI_INTERFACE*)dldiAddr)) {
 		return;
 	}
 
-	extern DLDI_INTERFACE _io_dldi_stub;
 	DLDI_INTERFACE* device = (DLDI_INTERFACE*)dldiAddr;
 	size_t dldiSize;
 
@@ -217,12 +346,7 @@ TWL_CODE void dldiLoadFromBin (const u8 dldiAddr[]) {
 	}
 	dldiSize = (dldiSize + 0x03) & ~0x03; 		// Round up to nearest integer multiple
 
-	// Clear unused space
-	toncset(&_io_dldi_stub, 0, 0x4000);
-
-	tonccpy(&_io_dldi_stub, device, dldiSize);
-
-	dldiFixDriverAddresses (&_io_dldi_stub);
+	dldiRelocateBinary ((data_t*)dldiAddr, dldiSize);
 
 	if (device->ioInterface.features & FEATURE_SLOT_GBA) {
 		sysSetCartOwner(BUS_OWNER_ARM9);