303 lines
8.1 KiB
C
303 lines
8.1 KiB
C
/*
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* AVR32-specific kernel module loader
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*
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* Copyright (C) 2005-2006 Atmel Corporation
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*
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* GOT initialization parts are based on the s390 version
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* Copyright (C) 2002, 2003 IBM Deutschland Entwicklung GmbH,
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* IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/bug.h>
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#include <linux/elf.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleloader.h>
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#include <linux/vmalloc.h>
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void module_free(struct module *mod, void *module_region)
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{
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vfree(mod->arch.syminfo);
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mod->arch.syminfo = NULL;
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vfree(module_region);
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}
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static inline int check_rela(Elf32_Rela *rela, struct module *module,
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char *strings, Elf32_Sym *symbols)
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{
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struct mod_arch_syminfo *info;
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info = module->arch.syminfo + ELF32_R_SYM(rela->r_info);
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switch (ELF32_R_TYPE(rela->r_info)) {
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case R_AVR32_GOT32:
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case R_AVR32_GOT16:
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case R_AVR32_GOT8:
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case R_AVR32_GOT21S:
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case R_AVR32_GOT18SW: /* mcall */
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case R_AVR32_GOT16S: /* ld.w */
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if (rela->r_addend != 0) {
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printk(KERN_ERR
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"GOT relocation against %s at offset %u with addend\n",
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strings + symbols[ELF32_R_SYM(rela->r_info)].st_name,
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rela->r_offset);
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return -ENOEXEC;
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}
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if (info->got_offset == -1UL) {
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info->got_offset = module->arch.got_size;
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module->arch.got_size += sizeof(void *);
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}
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pr_debug("GOT[%3lu] %s\n", info->got_offset,
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strings + symbols[ELF32_R_SYM(rela->r_info)].st_name);
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break;
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}
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return 0;
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}
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int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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char *secstrings, struct module *module)
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{
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Elf32_Shdr *symtab;
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Elf32_Sym *symbols;
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Elf32_Rela *rela;
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char *strings;
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int nrela, i, j;
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int ret;
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/* Find the symbol table */
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symtab = NULL;
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for (i = 0; i < hdr->e_shnum; i++)
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switch (sechdrs[i].sh_type) {
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case SHT_SYMTAB:
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symtab = &sechdrs[i];
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break;
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}
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if (!symtab) {
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printk(KERN_ERR "module %s: no symbol table\n", module->name);
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return -ENOEXEC;
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}
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/* Allocate room for one syminfo structure per symbol. */
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module->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
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module->arch.syminfo = vmalloc(module->arch.nsyms
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* sizeof(struct mod_arch_syminfo));
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if (!module->arch.syminfo)
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return -ENOMEM;
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symbols = (void *)hdr + symtab->sh_offset;
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strings = (void *)hdr + sechdrs[symtab->sh_link].sh_offset;
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for (i = 0; i < module->arch.nsyms; i++) {
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if (symbols[i].st_shndx == SHN_UNDEF &&
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strcmp(strings + symbols[i].st_name,
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"_GLOBAL_OFFSET_TABLE_") == 0)
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/* "Define" it as absolute. */
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symbols[i].st_shndx = SHN_ABS;
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module->arch.syminfo[i].got_offset = -1UL;
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module->arch.syminfo[i].got_initialized = 0;
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}
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/* Allocate GOT entries for symbols that need it. */
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module->arch.got_size = 0;
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for (i = 0; i < hdr->e_shnum; i++) {
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if (sechdrs[i].sh_type != SHT_RELA)
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continue;
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nrela = sechdrs[i].sh_size / sizeof(Elf32_Rela);
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rela = (void *)hdr + sechdrs[i].sh_offset;
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for (j = 0; j < nrela; j++) {
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ret = check_rela(rela + j, module,
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strings, symbols);
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if (ret)
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goto out_free_syminfo;
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}
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}
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/*
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* Increase core size to make room for GOT and set start
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* offset for GOT.
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*/
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module->core_size = ALIGN(module->core_size, 4);
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module->arch.got_offset = module->core_size;
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module->core_size += module->arch.got_size;
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return 0;
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out_free_syminfo:
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vfree(module->arch.syminfo);
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module->arch.syminfo = NULL;
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return ret;
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}
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static inline int reloc_overflow(struct module *module, const char *reloc_name,
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Elf32_Addr relocation)
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{
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printk(KERN_ERR "module %s: Value %lx does not fit relocation %s\n",
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module->name, (unsigned long)relocation, reloc_name);
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return -ENOEXEC;
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}
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#define get_u16(loc) (*((uint16_t *)loc))
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#define put_u16(loc, val) (*((uint16_t *)loc) = (val))
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int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relindex,
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struct module *module)
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{
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Elf32_Shdr *symsec = sechdrs + symindex;
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Elf32_Shdr *relsec = sechdrs + relindex;
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Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
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Elf32_Rela *rel = (void *)relsec->sh_addr;
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unsigned int i;
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int ret = 0;
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for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rela); i++, rel++) {
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struct mod_arch_syminfo *info;
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Elf32_Sym *sym;
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Elf32_Addr relocation;
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uint32_t *location;
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uint32_t value;
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location = (void *)dstsec->sh_addr + rel->r_offset;
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sym = (Elf32_Sym *)symsec->sh_addr + ELF32_R_SYM(rel->r_info);
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relocation = sym->st_value + rel->r_addend;
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info = module->arch.syminfo + ELF32_R_SYM(rel->r_info);
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/* Initialize GOT entry if necessary */
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switch (ELF32_R_TYPE(rel->r_info)) {
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case R_AVR32_GOT32:
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case R_AVR32_GOT16:
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case R_AVR32_GOT8:
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case R_AVR32_GOT21S:
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case R_AVR32_GOT18SW:
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case R_AVR32_GOT16S:
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if (!info->got_initialized) {
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Elf32_Addr *gotent;
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gotent = (module->module_core
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+ module->arch.got_offset
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+ info->got_offset);
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*gotent = relocation;
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info->got_initialized = 1;
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}
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relocation = info->got_offset;
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break;
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}
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switch (ELF32_R_TYPE(rel->r_info)) {
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case R_AVR32_32:
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case R_AVR32_32_CPENT:
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*location = relocation;
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break;
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case R_AVR32_22H_PCREL:
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relocation -= (Elf32_Addr)location;
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if ((relocation & 0xffe00001) != 0
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&& (relocation & 0xffc00001) != 0xffc00000)
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return reloc_overflow(module,
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"R_AVR32_22H_PCREL",
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relocation);
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relocation >>= 1;
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value = *location;
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value = ((value & 0xe1ef0000)
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| (relocation & 0xffff)
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| ((relocation & 0x10000) << 4)
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| ((relocation & 0x1e0000) << 8));
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*location = value;
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break;
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case R_AVR32_11H_PCREL:
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relocation -= (Elf32_Addr)location;
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if ((relocation & 0xfffffc01) != 0
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&& (relocation & 0xfffff801) != 0xfffff800)
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return reloc_overflow(module,
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"R_AVR32_11H_PCREL",
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relocation);
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value = get_u16(location);
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value = ((value & 0xf00c)
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| ((relocation & 0x1fe) << 3)
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| ((relocation & 0x600) >> 9));
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put_u16(location, value);
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break;
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case R_AVR32_9H_PCREL:
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relocation -= (Elf32_Addr)location;
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if ((relocation & 0xffffff01) != 0
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&& (relocation & 0xfffffe01) != 0xfffffe00)
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return reloc_overflow(module,
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"R_AVR32_9H_PCREL",
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relocation);
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value = get_u16(location);
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value = ((value & 0xf00f)
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| ((relocation & 0x1fe) << 3));
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put_u16(location, value);
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break;
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case R_AVR32_9UW_PCREL:
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relocation -= ((Elf32_Addr)location) & 0xfffffffc;
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if ((relocation & 0xfffffc03) != 0)
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return reloc_overflow(module,
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"R_AVR32_9UW_PCREL",
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relocation);
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value = get_u16(location);
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value = ((value & 0xf80f)
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| ((relocation & 0x1fc) << 2));
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put_u16(location, value);
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break;
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case R_AVR32_GOTPC:
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/*
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* R6 = PC - (PC - GOT)
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*
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* At this point, relocation contains the
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* value of PC. Just subtract the value of
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* GOT, and we're done.
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*/
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pr_debug("GOTPC: PC=0x%x, got_offset=0x%lx, core=0x%p\n",
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relocation, module->arch.got_offset,
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module->module_core);
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relocation -= ((unsigned long)module->module_core
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+ module->arch.got_offset);
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*location = relocation;
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break;
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case R_AVR32_GOT18SW:
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if ((relocation & 0xfffe0003) != 0
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&& (relocation & 0xfffc0003) != 0xffff0000)
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return reloc_overflow(module, "R_AVR32_GOT18SW",
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relocation);
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relocation >>= 2;
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/* fall through */
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case R_AVR32_GOT16S:
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if ((relocation & 0xffff8000) != 0
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&& (relocation & 0xffff0000) != 0xffff0000)
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return reloc_overflow(module, "R_AVR32_GOT16S",
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relocation);
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pr_debug("GOT reloc @ 0x%x -> %u\n",
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rel->r_offset, relocation);
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value = *location;
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value = ((value & 0xffff0000)
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| (relocation & 0xffff));
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*location = value;
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break;
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default:
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printk(KERN_ERR "module %s: Unknown relocation: %u\n",
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module->name, ELF32_R_TYPE(rel->r_info));
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return -ENOEXEC;
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}
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}
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return ret;
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}
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int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
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struct module *module)
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{
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vfree(module->arch.syminfo);
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module->arch.syminfo = NULL;
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return 0;
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}
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