Initial commit

backends/plugins/elf/ppc-loader.cpp

@@ -0,0 +1,127 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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/>.
+ *
+ */
+
+#include "common/scummsys.h"
+
+#if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) && defined(PPC_TARGET)
+
+#include "backends/plugins/elf/elf-loader.h"
+#include "backends/plugins/elf/ppc-loader.h"
+
+#include "common/debug.h"
+
+bool PPCDLObject::relocate(Elf32_Off offset, Elf32_Word size, byte *relSegment) {
+	Elf32_Rela *rel = NULL;
+
+	if (!(rel = (Elf32_Rela *)malloc(size))) {
+		warning("elfloader: Could not allocate %d bytes for the relocation table", size);
+		return false;
+	}
+
+	if (!_file->seek(offset, SEEK_SET) || _file->read(rel, size) != size) {
+		warning("elfloader: Relocation table load failed.");
+		free(rel);
+		return false;
+	}
+
+	uint32 cnt = size / sizeof(*rel);
+
+	debug(2, "elfloader: Loaded relocation table. %d entries. base address=%p", cnt, relSegment);
+
+	uint32 *src;
+	uint32 value;
+
+	for (uint32 i = 0; i < cnt; i++) {
+		// Get the symbol this relocation entry is referring to
+		Elf32_Sym *sym = _symtab + (REL_INDEX(rel[i].r_info));
+
+		// Get the target instruction in the code
+		src = (uint32 *)((char *)relSegment + rel[i].r_offset - _segmentVMA);
+		value = sym->st_value + rel[i].r_addend;
+
+		//debug(8, "elfloader: i=%05d %p +0x%04x: (0x%08x) 0x%08x ", i, src, rel[i].r_addend, sym->st_value, *src);
+
+		switch (REL_TYPE(rel[i].r_info)) {
+		case R_PPC_NONE:
+			debug(8, "elfloader: R_PPC_NONE");
+			break;
+		case R_PPC_ADDR32:
+			*src = value;
+			debug(8, "elfloader: R_PPC_ADDR32 -> 0x%08x", *src);
+			break;
+		case R_PPC_ADDR16_LO:
+			*(uint16 *)src = value;
+			debug(8, "elfloader: R_PPC_ADDR16_LO -> 0x%08x", *src);
+			break;
+		case R_PPC_ADDR16_HI:
+			*(uint16 *)src = value >> 16;
+			debug(8, "elfloader: R_PPC_ADDR16_HA -> 0x%08x", *src);
+			break;
+		case R_PPC_ADDR16_HA:
+			*(uint16 *)src = (value + 0x8000) >> 16;
+			debug(8, "elfloader: R_PPC_ADDR16_HA -> 0x%08x", *src);
+			break;
+		case R_PPC_REL24:
+			*src = (*src & ~0x03fffffc) | ((value - (uint32)src) & 0x03fffffc);
+			debug(8, "elfloader: R_PPC_REL24 -> 0x%08x", *src);
+			break;
+		case R_PPC_REL32:
+			*src = value - (uint32)src;
+			debug(8, "elfloader: R_PPC_REL32 -> 0x%08x", *src);
+			break;
+		default:
+			warning("elfloader: Unknown relocation type %d", REL_TYPE(rel[i].r_info));
+			free(rel);
+			return false;
+		}
+	}
+
+	free(rel);
+	return true;
+}
+
+bool PPCDLObject::relocateRels(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
+	for (uint32 i = 0; i < ehdr->e_shnum; i++) {
+		Elf32_Shdr *curShdr = &(shdr[i]);
+
+		if ((curShdr->sh_type == SHT_REL) &&
+				curShdr->sh_entsize == sizeof(Elf32_Rel) &&
+				int32(curShdr->sh_link) == _symtab_sect &&
+				curShdr->sh_info < ehdr->e_shnum &&
+				(shdr[curShdr->sh_info].sh_flags & SHF_ALLOC)) {
+			warning("elfloader: REL entries not supported!");
+			return false;
+		}
+
+		if ((curShdr->sh_type == SHT_RELA) &&
+				curShdr->sh_entsize == sizeof(Elf32_Rela) &&
+				int32(curShdr->sh_link) == _symtab_sect &&
+				curShdr->sh_info < ehdr->e_shnum &&
+				(shdr[curShdr->sh_info].sh_flags & SHF_ALLOC)) {
+			if (!relocate(curShdr->sh_offset, curShdr->sh_size, _segment))
+				return false;
+		}
+	}
+
+	return true;
+}
+
+#endif /* defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) && defined(PPC_TARGET) */