diff options
Diffstat (limited to 'arch/mips/kernel/module-elf32.c')
| -rw-r--r-- | arch/mips/kernel/module-elf32.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/arch/mips/kernel/module-elf32.c b/arch/mips/kernel/module-elf32.c new file mode 100644 index 00000000000..ffd216d6d6d --- /dev/null +++ b/arch/mips/kernel/module-elf32.c @@ -0,0 +1,250 @@ +/* + * 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 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 this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Copyright (C) 2001 Rusty Russell. + * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org) + */ + +#undef DEBUG + +#include <linux/moduleloader.h> +#include <linux/elf.h> +#include <linux/vmalloc.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/string.h> +#include <linux/kernel.h> + +struct mips_hi16 { + struct mips_hi16 *next; + Elf32_Addr *addr; + Elf32_Addr value; +}; + +static struct mips_hi16 *mips_hi16_list; + +void *module_alloc(unsigned long size) +{ + if (size == 0) + return NULL; + return vmalloc(size); +} + + +/* Free memory returned from module_alloc */ +void module_free(struct module *mod, void *module_region) +{ + vfree(module_region); + /* FIXME: If module_region == mod->init_region, trim exception + table entries. */ +} + +int module_frob_arch_sections(Elf_Ehdr *hdr, + Elf_Shdr *sechdrs, + char *secstrings, + struct module *mod) +{ + return 0; +} + +static int apply_r_mips_none(struct module *me, uint32_t *location, + Elf32_Addr v) +{ + return 0; +} + +static int apply_r_mips_32(struct module *me, uint32_t *location, + Elf32_Addr v) +{ + *location += v; + + return 0; +} + +static int apply_r_mips_26(struct module *me, uint32_t *location, + Elf32_Addr v) +{ + if (v % 4) { + printk(KERN_ERR "module %s: dangerous relocation\n", me->name); + return -ENOEXEC; + } + + if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { + printk(KERN_ERR + "module %s: relocation overflow\n", + me->name); + return -ENOEXEC; + } + + *location = (*location & ~0x03ffffff) | + ((*location + (v >> 2)) & 0x03ffffff); + + return 0; +} + +static int apply_r_mips_hi16(struct module *me, uint32_t *location, + Elf32_Addr v) +{ + struct mips_hi16 *n; + + /* + * We cannot relocate this one now because we don't know the value of + * the carry we need to add. Save the information, and let LO16 do the + * actual relocation. + */ + n = kmalloc(sizeof *n, GFP_KERNEL); + if (!n) + return -ENOMEM; + + n->addr = location; + n->value = v; + n->next = mips_hi16_list; + mips_hi16_list = n; + + return 0; +} + +static int apply_r_mips_lo16(struct module *me, uint32_t *location, + Elf32_Addr v) +{ + unsigned long insnlo = *location; + Elf32_Addr val, vallo; + + /* Sign extend the addend we extract from the lo insn. */ + vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; + + if (mips_hi16_list != NULL) { + struct mips_hi16 *l; + + l = mips_hi16_list; + while (l != NULL) { + struct mips_hi16 *next; + unsigned long insn; + + /* + * The value for the HI16 had best be the same. + */ + if (v != l->value) + goto out_danger; + + /* + * Do the HI16 relocation. Note that we actually don't + * need to know anything about the LO16 itself, except + * where to find the low 16 bits of the addend needed + * by the LO16. + */ + insn = *l->addr; + val = ((insn & 0xffff) << 16) + vallo; + val += v; + + /* + * Account for the sign extension that will happen in + * the low bits. + */ + val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; + + insn = (insn & ~0xffff) | val; + *l->addr = insn; + + next = l->next; + kfree(l); + l = next; + } + + mips_hi16_list = NULL; + } + + /* + * Ok, we're done with the HI16 relocs. Now deal with the LO16. + */ + val = v + vallo; + insnlo = (insnlo & ~0xffff) | (val & 0xffff); + *location = insnlo; + + return 0; + +out_danger: + printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name); + + return -ENOEXEC; +} + +static int (*reloc_handlers[]) (struct module *me, uint32_t *location, + Elf32_Addr v) = { + [R_MIPS_NONE] = apply_r_mips_none, + [R_MIPS_32] = apply_r_mips_32, + [R_MIPS_26] = apply_r_mips_26, + [R_MIPS_HI16] = apply_r_mips_hi16, + [R_MIPS_LO16] = apply_r_mips_lo16 +}; + +int apply_relocate(Elf32_Shdr *sechdrs, + const char *strtab, + unsigned int symindex, + unsigned int relsec, + struct module *me) +{ + Elf32_Rel *rel = (void *) sechdrs[relsec].sh_addr; + Elf32_Sym *sym; + uint32_t *location; + unsigned int i; + Elf32_Addr v; + int res; + + pr_debug("Applying relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + + for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { + Elf32_Word r_info = rel[i].r_info; + + /* This is where to make the change */ + location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + + rel[i].r_offset; + /* This is the symbol it is referring to */ + sym = (Elf32_Sym *)sechdrs[symindex].sh_addr + + ELF32_R_SYM(r_info); + if (!sym->st_value) { + printk(KERN_WARNING "%s: Unknown symbol %s\n", + me->name, strtab + sym->st_name); + return -ENOENT; + } + + v = sym->st_value; + + res = reloc_handlers[ELF32_R_TYPE(r_info)](me, location, v); + if (res) + return res; + } + + return 0; +} + +int apply_relocate_add(Elf32_Shdr *sechdrs, + const char *strtab, + unsigned int symindex, + unsigned int relsec, + struct module *me) +{ + /* + * Current binutils always generate .rela relocations. Keep smiling + * if it's empty, abort otherwise. + */ + if (!sechdrs[relsec].sh_size) + return 0; + + printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", + me->name); + return -ENOEXEC; +} |