275 lines
7.4 KiB
C
275 lines
7.4 KiB
C
/* dl-386.c - arch-dependent part of loadable module support */
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/*
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* VasEBoot -- GRand Unified Bootloader
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* Copyright (C) 2002,2005,2007,2009 Free Software Foundation, Inc.
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*
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* VasEBoot is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* VasEBoot is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with VasEBoot. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <VasEBoot/dl.h>
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#include <VasEBoot/elf.h>
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#include <VasEBoot/misc.h>
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#include <VasEBoot/err.h>
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#include <VasEBoot/cpu/types.h>
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#include <VasEBoot/mm.h>
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#include <VasEBoot/i18n.h>
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/* Dummy __gnu_local_gp. Resolved by linker. */
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static char __gnu_local_gp_dummy;
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static char _gp_disp_dummy;
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/* Check if EHDR is a valid ELF header. */
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VasEBoot_err_t
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VasEBoot_arch_dl_check_header (void *ehdr)
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{
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Elf_Ehdr *e = ehdr;
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/* Check the magic numbers. */
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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if (e->e_ident[EI_CLASS] != ELFCLASS32
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|| e->e_ident[EI_DATA] != ELFDATA2MSB
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|| e->e_machine != EM_MIPS)
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#else
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if (e->e_ident[EI_CLASS] != ELFCLASS32
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|| e->e_ident[EI_DATA] != ELFDATA2LSB
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|| e->e_machine != EM_MIPS)
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#endif
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return VasEBoot_error (VasEBoot_ERR_BAD_OS, N_("invalid arch-dependent ELF magic"));
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return VasEBoot_ERR_NONE;
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}
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#pragma GCC diagnostic ignored "-Wcast-align"
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VasEBoot_err_t
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VasEBoot_arch_dl_get_tramp_got_size (const void *ehdr, VasEBoot_size_t *tramp,
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VasEBoot_size_t *got)
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{
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const Elf_Ehdr *e = ehdr;
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const Elf_Shdr *s;
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/* FIXME: suboptimal. */
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VasEBoot_size_t gp_size = 0;
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unsigned i;
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*tramp = 0;
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*got = 0;
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for (i = 0, s = (const Elf_Shdr *) ((const char *) e + e->e_shoff);
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i < e->e_shnum;
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i++, s = (const Elf_Shdr *) ((const char *) s + e->e_shentsize))
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if (s->sh_type == SHT_REL)
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{
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const Elf_Rel *rel, *max;
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for (rel = (const Elf_Rel *) ((const char *) e + s->sh_offset),
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max = rel + s->sh_size / s->sh_entsize;
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rel < max;
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rel++)
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switch (ELF_R_TYPE (rel->r_info))
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{
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case R_MIPS_GOT16:
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case R_MIPS_CALL16:
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case R_MIPS_GPREL32:
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gp_size += 4;
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break;
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}
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}
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if (gp_size > 0x08000)
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return VasEBoot_error (VasEBoot_ERR_OUT_OF_RANGE, "__gnu_local_gp is too big\n");
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*got = gp_size;
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return VasEBoot_ERR_NONE;
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}
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/* Relocate symbols. */
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VasEBoot_err_t
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VasEBoot_arch_dl_relocate_symbols (VasEBoot_dl_t mod, void *ehdr,
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Elf_Shdr *s, VasEBoot_dl_segment_t seg)
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{
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VasEBoot_uint32_t gp0;
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Elf_Ehdr *e = ehdr;
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if (!mod->reginfo)
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{
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unsigned i;
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Elf_Shdr *ri;
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/* Find reginfo. */
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for (i = 0, ri = (Elf_Shdr *) ((char *) ehdr + e->e_shoff);
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i < e->e_shnum;
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i++, ri = (Elf_Shdr *) ((char *) ri + e->e_shentsize))
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if (ri->sh_type == SHT_MIPS_REGINFO)
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break;
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if (i == e->e_shnum)
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return VasEBoot_error (VasEBoot_ERR_BAD_MODULE, "no reginfo found");
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mod->reginfo = (VasEBoot_uint32_t *)((char *) ehdr + ri->sh_offset);
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}
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gp0 = mod->reginfo[5];
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Elf_Rel *rel, *max;
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for (rel = (Elf_Rel *) ((char *) e + s->sh_offset),
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max = (Elf_Rel *) ((char *) rel + s->sh_size);
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rel < max;
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rel = (Elf_Rel *) ((char *) rel + s->sh_entsize))
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{
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VasEBoot_uint8_t *addr;
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Elf_Sym *sym;
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VasEBoot_uint32_t sym_value;
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if (seg->size < rel->r_offset)
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return VasEBoot_error (VasEBoot_ERR_BAD_MODULE,
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"reloc offset is out of the segment");
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addr = (VasEBoot_uint8_t *) ((char *) seg->addr + rel->r_offset);
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sym = (Elf_Sym *) ((char *) mod->symtab
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+ mod->symsize * ELF_R_SYM (rel->r_info));
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sym_value = sym->st_value;
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if (s->sh_type == SHT_RELA)
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{
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sym_value += ((Elf_Rela *) rel)->r_addend;
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}
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if (sym_value == (VasEBoot_addr_t) &__gnu_local_gp_dummy)
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sym_value = (VasEBoot_addr_t) mod->got;
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else if (sym_value == (VasEBoot_addr_t) &_gp_disp_dummy)
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{
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sym_value = (VasEBoot_addr_t) mod->got - (VasEBoot_addr_t) addr;
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if (ELF_R_TYPE (rel->r_info) == R_MIPS_LO16)
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/* ABI mandates +4 even if partner lui doesn't
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immediately precede addiu. */
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sym_value += 4;
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}
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switch (ELF_R_TYPE (rel->r_info))
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{
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case R_MIPS_HI16:
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{
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VasEBoot_uint32_t value;
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Elf_Rel *rel2;
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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addr += 2;
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#endif
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/* Handle partner lo16 relocation. Lower part is
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treated as signed. Hence add 0x8000 to compensate.
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*/
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value = (*(VasEBoot_uint16_t *) addr << 16)
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+ sym_value + 0x8000;
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for (rel2 = rel + 1; rel2 < max; rel2++)
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if (ELF_R_SYM (rel2->r_info)
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== ELF_R_SYM (rel->r_info)
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&& ELF_R_TYPE (rel2->r_info) == R_MIPS_LO16)
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{
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value += *(VasEBoot_int16_t *)
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((char *) seg->addr + rel2->r_offset
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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+ 2
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#endif
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);
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break;
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}
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*(VasEBoot_uint16_t *) addr = (value >> 16) & 0xffff;
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}
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break;
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case R_MIPS_LO16:
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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addr += 2;
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#endif
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*(VasEBoot_uint16_t *) addr += sym_value & 0xffff;
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break;
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case R_MIPS_32:
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*(VasEBoot_uint32_t *) addr += sym_value;
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break;
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case R_MIPS_GPREL32:
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*(VasEBoot_uint32_t *) addr = sym_value
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+ *(VasEBoot_uint32_t *) addr + gp0 - (VasEBoot_uint32_t)mod->got;
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break;
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case R_MIPS_26:
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{
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VasEBoot_uint32_t value;
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VasEBoot_uint32_t raw;
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raw = (*(VasEBoot_uint32_t *) addr) & 0x3ffffff;
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value = raw << 2;
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value += sym_value;
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raw = (value >> 2) & 0x3ffffff;
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*(VasEBoot_uint32_t *) addr =
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raw | ((*(VasEBoot_uint32_t *) addr) & 0xfc000000);
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}
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break;
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case R_MIPS_GOT16:
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if (ELF_ST_BIND (sym->st_info) == STB_LOCAL)
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{
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Elf_Rel *rel2;
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/* Handle partner lo16 relocation. Lower part is
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treated as signed. Hence add 0x8000 to compensate.
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*/
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sym_value += (*(VasEBoot_uint16_t *) addr << 16)
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+ 0x8000;
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for (rel2 = rel + 1; rel2 < max; rel2++)
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if (ELF_R_SYM (rel2->r_info)
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== ELF_R_SYM (rel->r_info)
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&& ELF_R_TYPE (rel2->r_info) == R_MIPS_LO16)
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{
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sym_value += *(VasEBoot_int16_t *)
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((char *) seg->addr + rel2->r_offset
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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+ 2
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#endif
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);
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break;
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}
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sym_value &= 0xffff0000;
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*(VasEBoot_uint16_t *) addr = 0;
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}
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/* Fallthrough. */
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case R_MIPS_CALL16:
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{
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VasEBoot_uint32_t *gpptr = mod->gotptr;
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/* FIXME: reuse*/
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#ifdef VasEBoot_CPU_WORDS_BIGENDIAN
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addr += 2;
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#endif
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*gpptr = sym_value + *(VasEBoot_uint16_t *) addr;
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*(VasEBoot_uint16_t *) addr
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= sizeof (VasEBoot_uint32_t) * (gpptr - (VasEBoot_uint32_t *) mod->got);
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mod->gotptr = gpptr + 1;
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break;
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}
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case R_MIPS_JALR:
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break;
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default:
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{
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return VasEBoot_error (VasEBoot_ERR_NOT_IMPLEMENTED_YET,
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N_("relocation 0x%x is not implemented yet"),
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ELF_R_TYPE (rel->r_info));
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}
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break;
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}
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}
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return VasEBoot_ERR_NONE;
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}
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void
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VasEBoot_arch_dl_init_linker (void)
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{
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VasEBoot_dl_register_symbol ("__gnu_local_gp", &__gnu_local_gp_dummy, 0, 0);
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VasEBoot_dl_register_symbol ("_gp_disp", &_gp_disp_dummy, 0, 0);
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}
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