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/*
* 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)
* Copyright (C) 2005 Thiemo Seufer
* Copyright (C) 2015 Imagination Technologies Ltd.
*/
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/moduleloader.h>
extern int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v);
static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v)
{
*location = v;
return 0;
}
static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
{
if (v % 4) {
pr_err("module %s: dangerous R_MIPS_26 RELA relocation\n",
me->name);
return -ENOEXEC;
}
if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
pr_err("module %s: relocation overflow\n", me->name);
return -ENOEXEC;
}
*location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
return 0;
}
static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
{
*location = (*location & 0xffff0000) |
((((long long) v + 0x8000LL) >> 16) & 0xffff);
return 0;
}
static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
{
*location = (*location & 0xffff0000) | (v & 0xffff);
return 0;
}
static int apply_r_mips_pc_rela(struct module *me, u32 *location, Elf_Addr v,
unsigned bits)
{
unsigned long mask = GENMASK(bits - 1, 0);
unsigned long se_bits;
long offset;
if (v % 4) {
pr_err("module %s: dangerous R_MIPS_PC%u RELA relocation\n",
me->name, bits);
return -ENOEXEC;
}
offset = ((long)v - (long)location) >> 2;
/* check the sign bit onwards are identical - ie. we didn't overflow */
se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
if ((offset & ~mask) != (se_bits & ~mask)) {
pr_err("module %s: relocation overflow\n", me->name);
return -ENOEXEC;
}
*location = (*location & ~mask) | (offset & mask);
return 0;
}
static int apply_r_mips_pc16_rela(struct module *me, u32 *location, Elf_Addr v)
{
return apply_r_mips_pc_rela(me, location, v, 16);
}
static int apply_r_mips_pc21_rela(struct module *me, u32 *location, Elf_Addr v)
{
return apply_r_mips_pc_rela(me, location, v, 21);
}
static int apply_r_mips_pc26_rela(struct module *me, u32 *location, Elf_Addr v)
{
return apply_r_mips_pc_rela(me, location, v, 26);
}
static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
{
*(Elf_Addr *)location = v;
return 0;
}
static int apply_r_mips_higher_rela(struct module *me, u32 *location,
Elf_Addr v)
{
*location = (*location & 0xffff0000) |
((((long long) v + 0x80008000LL) >> 32) & 0xffff);
return 0;
}
static int apply_r_mips_highest_rela(struct module *me, u32 *location,
Elf_Addr v)
{
*location = (*location & 0xffff0000) |
((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
return 0;
}
static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
Elf_Addr v) = {
[R_MIPS_NONE] = apply_r_mips_none,
[R_MIPS_32] = apply_r_mips_32_rela,
[R_MIPS_26] = apply_r_mips_26_rela,
[R_MIPS_HI16] = apply_r_mips_hi16_rela,
[R_MIPS_LO16] = apply_r_mips_lo16_rela,
[R_MIPS_PC16] = apply_r_mips_pc16_rela,
[R_MIPS_64] = apply_r_mips_64_rela,
[R_MIPS_HIGHER] = apply_r_mips_higher_rela,
[R_MIPS_HIGHEST] = apply_r_mips_highest_rela,
[R_MIPS_PC21_S2] = apply_r_mips_pc21_rela,
[R_MIPS_PC26_S2] = apply_r_mips_pc26_rela,
};
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
{
Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
int (*handler)(struct module *me, u32 *location, Elf_Addr v);
Elf_Sym *sym;
u32 *location;
unsigned int i, type;
Elf_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++) {
/* 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 = (Elf_Sym *)sechdrs[symindex].sh_addr
+ ELF_MIPS_R_SYM(rel[i]);
if (sym->st_value >= -MAX_ERRNO) {
/* Ignore unresolved weak symbol */
if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
continue;
pr_warn("%s: Unknown symbol %s\n",
me->name, strtab + sym->st_name);
return -ENOENT;
}
type = ELF_MIPS_R_TYPE(rel[i]);
if (type < ARRAY_SIZE(reloc_handlers_rela))
handler = reloc_handlers_rela[type];
else
handler = NULL;
if (!handler) {
pr_err("%s: Unknown relocation type %u\n",
me->name, type);
return -EINVAL;
}
v = sym->st_value + rel[i].r_addend;
res = handler(me, location, v);
if (res)
return res;
}
return 0;
}
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