/*
* File: arch/blackfin/kernel/module.c
* Based on:
* Author:
*
* Created:
* Description:
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* 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.
*/
#include <common.h>
#include <elf.h>
#include <module.h>
#include <malloc.h>
#include <errno.h>
/*
* handle arithmetic relocations.
* See binutils/bfd/elf32-bfin.c for more details
*/
#define RELOC_STACK_SIZE 100
static uint32_t reloc_stack[RELOC_STACK_SIZE];
static unsigned int reloc_stack_tos;
#define is_reloc_stack_empty() ((reloc_stack_tos > 0)?0:1)
static void reloc_stack_push(uint32_t value)
{
reloc_stack[reloc_stack_tos++] = value;
}
static uint32_t reloc_stack_pop(void)
{
return reloc_stack[--reloc_stack_tos];
}
static uint32_t reloc_stack_operate(unsigned int oper, struct module *mod)
{
uint32_t value;
switch (oper) {
case R_add:
value = reloc_stack[reloc_stack_tos - 2] +
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_sub:
value = reloc_stack[reloc_stack_tos - 2] -
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_mult:
value = reloc_stack[reloc_stack_tos - 2] *
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_div:
value = reloc_stack[reloc_stack_tos - 2] /
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_mod:
value = reloc_stack[reloc_stack_tos - 2] %
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_lshift:
value = reloc_stack[reloc_stack_tos - 2] <<
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_rshift:
value = reloc_stack[reloc_stack_tos - 2] >>
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_and:
value = reloc_stack[reloc_stack_tos - 2] &
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_or:
value = reloc_stack[reloc_stack_tos - 2] |
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_xor:
value = reloc_stack[reloc_stack_tos - 2] ^
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_land:
value = reloc_stack[reloc_stack_tos - 2] &&
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_lor:
value = reloc_stack[reloc_stack_tos - 2] ||
reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 2;
break;
case R_neg:
value = -reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos--;
break;
case R_comp:
value = ~reloc_stack[reloc_stack_tos - 1];
reloc_stack_tos -= 1;
break;
default:
printf("module %s: unhandled reloction\n",
mod->name);
return 0;
}
/* now push the new value back on stack */
reloc_stack_push(value);
return value;
}
int
apply_relocate(Elf_Shdr * sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec, struct module *me)
{
printf("module %s: .rel unsupported\n", me->name);
return -ENOEXEC;
}
/*************************************************************************/
/* FUNCTION : apply_relocate_add */
/* ABSTRACT : Blackfin specific relocation handling for the loadable */
/* modules. Modules are expected to be .o files. */
/* Arithmetic relocations are handled. */
/* We do not expect LSETUP to be split and hence is not */
/* handled. */
/* R_byte and R_byte2 are also not handled as the gas */
/* does not generate it. */
/*************************************************************************/
int
apply_relocate_add(Elf_Shdr * sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *mod)
{
unsigned int i;
unsigned short tmp;
Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
uint32_t *location32;
uint16_t *location16;
uint32_t value;
debug("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
location16 =
(uint16_t *) (sechdrs[sechdrs[relsec].sh_info].sh_addr +
rel[i].r_offset);
location32 = (uint32_t *) location16;
/* This is the symbol it is referring to. Note that all
undefined symbols have been resolved. */
sym = (Elf32_Sym *) sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rel[i].r_info);
if (is_reloc_stack_empty()) {
value = sym->st_value;
} else {
value = reloc_stack_pop();
}
value += rel[i].r_addend;
debug("location is %x, value is %x type is %d \n",
(unsigned int) location32, value,
ELF32_R_TYPE(rel[i].r_info));
switch (ELF32_R_TYPE(rel[i].r_info)) {
case R_pcrel24:
case R_pcrel24_jump_l:
/* Add the value, subtract its postition */
location16 =
(uint16_t *) (sechdrs[sechdrs[relsec].sh_info].
sh_addr + rel[i].r_offset - 2);
location32 = (uint32_t *) location16;
value -= (uint32_t) location32;
value >>= 1;
debug("value is %x, before %x-%x after %x-%x\n", value,
*location16, *(location16 + 1),
(*location16 & 0xff00) | (value >> 16 & 0x00ff),
value & 0xffff);
*location16 =
(*location16 & 0xff00) | (value >> 16 & 0x00ff);
*(location16 + 1) = value & 0xffff;
break;
case R_pcrel12_jump:
case R_pcrel12_jump_s:
value -= (uint32_t) location32;
value >>= 1;
*location16 = (value & 0xfff);
break;
case R_pcrel10:
value -= (uint32_t) location32;
value >>= 1;
*location16 = (value & 0x3ff);
break;
case R_luimm16:
debug("before %x after %x\n", *location16,
(value & 0xffff));
tmp = (value & 0xffff);
*location16 = tmp;
break;
case R_huimm16:
debug("before %x after %x\n", *location16,
((value >> 16) & 0xffff));
tmp = ((value >> 16) & 0xffff);
*location16 = tmp;
break;
case R_rimm16:
*location16 = (value & 0xffff);
break;
case R_byte4_data:
debug("before %x after %x\n", *location32, value);
*location32 = value;
break;
case R_push:
reloc_stack_push(value);
break;
case R_const:
reloc_stack_push(rel[i].r_addend);
break;
case R_add:
case R_sub:
case R_mult:
case R_div:
case R_mod:
case R_lshift:
case R_rshift:
case R_and:
case R_or:
case R_xor:
case R_land:
case R_lor:
case R_neg:
case R_comp:
reloc_stack_operate(ELF32_R_TYPE(rel[i].r_info), mod);
break;
default:
printf("module %s: Unknown relocation: %u\n",
mod->name, ELF32_R_TYPE(rel[i].r_info));
return -ENOEXEC;
}
}
return 0;
}
#if 0
int
module_finalize(const Elf_Ehdr * hdr,
const Elf_Shdr * sechdrs, struct module *mod)
{
unsigned int i, strindex = 0, symindex = 0;
char *secstrings;
secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (i = 1; i < hdr->e_shnum; i++) {
/* Internal symbols and strings. */
if (sechdrs[i].sh_type == SHT_SYMTAB) {
symindex = i;
strindex = sechdrs[i].sh_link;
}
}
for (i = 1; i < hdr->e_shnum; i++) {
const char *strtab = (char *)sechdrs[strindex].sh_addr;
unsigned int info = sechdrs[i].sh_info;
/* Not a valid relocation section? */
if (info >= hdr->e_shnum)
continue;
if ((sechdrs[i].sh_type == SHT_RELA) &&
((strcmp(".rela.l1.text", secstrings + sechdrs[i].sh_name) == 0) ||
((strcmp(".rela.text", secstrings + sechdrs[i].sh_name) == 0) &&
(hdr->e_flags & FLG_CODE_IN_L1)))) {
apply_relocate_add((Elf_Shdr *) sechdrs, strtab,
symindex, i, mod);
}
}
return 0;
}
#endif
