From d5f442dc6bd63cfcdef2eae88b7e10f9671436ba Mon Sep 17 00:00:00 2001 From: Tony Puccinelli Date: Fri, 16 Jul 2010 20:44:11 +0000 Subject: put in initial relocations for R_ARM_ABS32, R_ARM_THM_CALL and R_ARM_V4BX svn-id: r50942 --- backends/platform/ds/arm9/source/dsloader.cpp | 83 +++++++++++++++++++++------ backends/platform/ds/arm9/source/elf32.h | 11 +--- 2 files changed, 70 insertions(+), 24 deletions(-) (limited to 'backends/platform/ds/arm9/source') diff --git a/backends/platform/ds/arm9/source/dsloader.cpp b/backends/platform/ds/arm9/source/dsloader.cpp index a4fe0573d2..2f953cc33b 100644 --- a/backends/platform/ds/arm9/source/dsloader.cpp +++ b/backends/platform/ds/arm9/source/dsloader.cpp @@ -27,7 +27,6 @@ #include #include -#include #include #include #include @@ -35,6 +34,7 @@ //#include "backends/fs/stdiostream.h" #include "backends/fs/ds/ds-fs.h" +#include "dsmain.h" #include "backends/platform/ds/arm9/source/dsloader.h" @@ -92,24 +92,74 @@ bool DLObject::relocate(Common::SeekableReadStream* DLFile, unsigned long offset // Treat each relocation entry. Loop over all of them int cnt = size / sizeof(*rel); - DBG("# of relocation entries is %d.\n", cnt); + DBG("Loaded relocation table. %d entries. base address=%p\n", cnt, relSegment); + + int a = 0; + unsigned int relocation = 0; - // TODO: Loop over relocation entries for (int i = 0; i < cnt; i++) { - //Elf32_Sym *sym = ???; + Elf32_Sym *sym = (Elf32_Sym *)(_symtab) + (REL_INDEX(rel[i].r_info)); + + unsigned int *target = (unsigned int *)((char *)relSegment + rel[i].r_offset); + + unsigned int origTarget = *target; // Save for debugging + + //DBG("%d, ", REL_TYPE(rel[i].r_info)); + + switch (REL_TYPE(rel[i].r_info)) { + + case R_ARM_ABS32: + if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section. + a = *target; // Get full 32 bits of addend + relocation = a + (Elf32_Addr)_segment; // Shift by main offset + + /*TODO: + * if (SYM_TYPE(sym->st_info) == STT_FUNC && symbol addresses a thumb instruction) { + * relocation |= 1; + * } + */ + + *target = relocation; + + DBG("R_ARM_ABS32: i=%d, a=%x, origTarget=%x, target=%x\n", i, a, origTarget, *target); + } + break; + + case R_ARM_THM_CALL: + + if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section. + a = *target & 0x00000fff; // Get the correct bits for addend: + a += ((*target & 0x0fff0000) >> 4); // Bits 0-11 of the first half-word encode the 12 most significant bits of the branch offset, + // bits 0-11 of the next half-word encode the 12 least significant bits. + a = (a << 8) >> 8; // sign-extend + a = a << 1; // branch offset is in units of half-bytes + + relocation = a + (Elf32_Addr)_segment; // Shift by main offset + + /*TODO: + * if (SYM_TYPE(sym->st_info) == STT_FUNC && symbol addresses a thumb instruction) { + * relocation |= 1; + * } + */ - //void *target = ???; + relocation -= rel[i].r_offset; - /*switch (REL_TYPE()) {*/ - //case ??? : - //TODO: Cases for each relocation type. - //break; - // default: - //seterror("Unknown relocation type %d.", ?? ?); + *target = relocation; + + DBG("R_ARM_THM_CALL: i=%d, a=%x, origTarget=%x, target=%x\n", i, a, origTarget, *target); + } + break; + + case R_ARM_V4BX: + DBG("R_ARM_V4BX: No relocation calculation necessary\n"); + break; + + default: + seterror("Unknown relocation type %d.", REL_TYPE(rel[i].r_info)); free(rel); return false; - // } + } } @@ -400,7 +450,8 @@ bool DLObject::open(const char *path) { //DLFile->finalize(); - //TODO?: flush data cache + //flush data cache + DC_FlushAll(); ctors_start = symbol("___plugin_ctors"); ctors_end = symbol("___plugin_ctors_end"); @@ -444,9 +495,9 @@ void *DLObject::symbol(const char *name) { Elf32_Sym *s = (Elf32_Sym *)_symtab; for (int c = _symbol_cnt; c--; s++) - //TODO: Figure out which symbols should be detected here - if ((s->st_info >> 4 == 1 || s->st_info >> 4 == 2) && - _strtab[s->st_name] == '_' && !strcmp(name, _strtab + s->st_name + 1)) { + // We can only import symbols that are global or weak in the plugin + if ((SYM_BIND(s->st_info) == STB_GLOBAL || SYM_BIND(s->st_info) == STB_WEAK) && + !strcmp(name, _strtab + s->st_name)) { // We found the symbol DBG("=> %p\n", (void*)s->st_value); diff --git a/backends/platform/ds/arm9/source/elf32.h b/backends/platform/ds/arm9/source/elf32.h index c7971891fe..8167a40551 100644 --- a/backends/platform/ds/arm9/source/elf32.h +++ b/backends/platform/ds/arm9/source/elf32.h @@ -174,18 +174,13 @@ typedef struct { } Elf32_Rel; // Access macros for the relocation info -#define REL_TYPE(x) ((unsigned char) (x)) /* Extract relocation type */ +#define REL_TYPE(x) ((unsigned char) (x)) /* Extract relocation type */ #define REL_INDEX(x) ((x)>>8) /* Extract relocation index into symbol table */ // ARM relocation types #define R_ARM_NONE 0 -#define R_ARM_PC24 1 #define R_ARM_ABS32 2 -#define R_ARM_COPY 20 -#define R_ARM_GLOB_DAT 21 -#define R_ARM_JUMP_SLOT 22 -#define R_ARM_BASE_PREL 25 -#define R_ARM_GOT_BREL 26 -#define R_ARM_PLT32 27 +#define R_ARM_THM_CALL 10 +#define R_ARM_V4BX 40 #endif /* BACKENDS_ELF_H */ -- cgit v1.2.3