/* dl.c - arch-dependent part of loadable module support */ /* * GRUB -- GRand Unified Bootloader * Copyright (C) 2002, 2004 Free Software Foundation, Inc. * * GRUB 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 2 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 GRUB; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include /* Check if EHDR is a valid ELF header. */ int grub_arch_dl_check_header (void *ehdr, unsigned size) { Elf32_Ehdr *e = ehdr; /* Check the header size. */ if (size < sizeof (Elf32_Ehdr)) return 0; /* Check the magic numbers. */ if (!((e->e_ident[EI_MAG0] == ELFMAG0) && (e->e_ident[EI_MAG1] == ELFMAG1) && (e->e_ident[EI_MAG2] == ELFMAG2) && (e->e_ident[EI_MAG3] == ELFMAG3) && (e->e_ident[EI_CLASS] == ELFCLASS32) && (e->e_ident[EI_DATA] == ELFDATA2MSB) && (e->e_ident[EI_VERSION] == EV_CURRENT) && (e->e_type == ET_REL) && (e->e_machine == EM_PPC) && (e->e_version == EV_CURRENT))) return 0; /* Make sure that every section is within the core. */ if (size < e->e_shoff + e->e_shentsize * e->e_shnum) return 0; return 1; } /* Relocate symbols. */ grub_err_t grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr) { Elf32_Ehdr *e = ehdr; Elf32_Shdr *s; Elf32_Sym *symtab; Elf32_Word entsize; unsigned i; /* Find a symbol table. */ for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff); i < e->e_shnum; i++, s = (Elf32_Shdr *) ((char *) s + e->e_shentsize)) if (s->sh_type == SHT_SYMTAB) break; if (i == e->e_shnum) return grub_error (GRUB_ERR_BAD_MODULE, "no symtab found"); symtab = (Elf32_Sym *) ((char *) e + s->sh_offset); entsize = s->sh_entsize; for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff); i < e->e_shnum; i++, s = (Elf32_Shdr *) ((char *) s + e->e_shentsize)) if (s->sh_type == SHT_RELA) { grub_dl_segment_t seg; /* Find the target segment. */ for (seg = mod->segment; seg; seg = seg->next) if (seg->section == s->sh_info) break; if (seg) { Elf32_Rela *rel, *max; for (rel = (Elf32_Rela *) ((char *) e + s->sh_offset), max = rel + s->sh_size / s->sh_entsize; rel < max; rel++) { Elf32_Word *addr; Elf32_Sym *sym; grub_uint32_t value; if (seg->size < rel->r_offset) return grub_error (GRUB_ERR_BAD_MODULE, "reloc offset is out of the segment"); addr = (Elf32_Word *) ((char *) seg->addr + rel->r_offset); sym = (Elf32_Sym *) ((char *) symtab + entsize * ELF32_R_SYM (rel->r_info)); /* On the PPC the value does not have an explicit addend, add it. */ value = sym->st_value + rel->r_addend; switch (ELF32_R_TYPE (rel->r_info)) { case R_PPC_ADDR16_LO: *(Elf32_Half *) addr = value; break; case R_PPC_REL24: { Elf32_Sword delta = value - (Elf32_Word) addr; if (delta << 6 >> 6 != delta) return grub_error (GRUB_ERR_BAD_MODULE, "Relocation overflow"); *addr = (*addr & 0xfc000003) | (delta & 0x3fffffc); break; } case R_PPC_ADDR16_HA: *(Elf32_Half *) addr = (value + 0x8000) >> 16; break; case R_PPC_ADDR32: *addr = value; break; } } } } return GRUB_ERR_NONE; }