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/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/moduleloader.h>
#include <linux/kernel.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <asm/unwind.h>
static inline void arc_write_me(unsigned short *addr, unsigned long value)
{
*addr = (value & 0xffff0000) >> 16;
*(addr + 1) = (value & 0xffff);
}
/* ARC specific section quirks - before relocation loop in generic loader
*
* For dwarf unwinding out of modules, this needs to
* 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
* -fasynchronous-unwind-tables it doesn't).
* 2. Since we are iterating thru sec hdr tbl anyways, make a note of
* the exact section index, for later use.
*/
int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstr, struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
int i;
mod->arch.unw_sec_idx = 0;
mod->arch.unw_info = NULL;
for (i = 1; i < hdr->e_shnum; i++) {
if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
sechdrs[i].sh_flags |= SHF_ALLOC;
mod->arch.unw_sec_idx = i;
break;
}
}
#endif
return 0;
}
void module_arch_cleanup(struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
if (mod->arch.unw_info)
unwind_remove_table(mod->arch.unw_info, 0);
#endif
}
int apply_relocate_add(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex, /* sec index for sym tbl */
unsigned int relsec, /* sec index for relo sec */
struct module *module)
{
int i, n;
Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym_entry, *sym_sec;
Elf32_Addr relocation;
Elf32_Addr location;
Elf32_Addr sec_to_patch;
int relo_type;
sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
pr_debug("\n========== Module Sym reloc ===========================\n");
pr_debug("Section to fixup %x\n", sec_to_patch);
pr_debug("=========================================================\n");
pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n");
pr_debug("=========================================================\n");
/* Loop thru entries in relocation section */
for (i = 0; i < n; i++) {
/* This is where to make the change */
location = sec_to_patch + rel_entry[i].r_offset;
/* This is the symbol it is referring to. Note that all
undefined symbols have been resolved. */
sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
relocation = sym_entry->st_value + rel_entry[i].r_addend;
pr_debug("\t%x\t\t%x\t\t%x %x %x [%s]\n",
rel_entry[i].r_offset, rel_entry[i].r_addend,
sym_entry->st_value, location, relocation,
strtab + sym_entry->st_name);
/* This assumes modules are built with -mlong-calls
* so any branches/jumps are absolute 32 bit jmps
* global data access again is abs 32 bit.
* Both of these are handled by same relocation type
*/
relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */
arc_write_me((unsigned short *)location, relocation);
else if (R_ARC_32 == relo_type) /* ( S + A ) */
*((Elf32_Addr *) location) = relocation;
else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */
*((Elf32_Addr *) location) = relocation - location;
else
goto relo_err;
}
return 0;
relo_err:
pr_err("%s: unknown relocation: %u\n",
module->name, ELF32_R_TYPE(rel_entry[i].r_info));
return -ENOEXEC;
}
/* Just before lift off: After sections have been relocated, we add the
* dwarf section to unwinder table pool
* This couldn't be done in module_frob_arch_sections() because
* relocations had not been applied by then
*/
int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
void *unw;
int unwsec = mod->arch.unw_sec_idx;
if (unwsec) {
unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
sechdrs[unwsec].sh_size);
mod->arch.unw_info = unw;
}
#endif
return 0;
}
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