Commit 430d0b88 authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle

MIPS: module: Unify rel & rela reloc handling

The module load code has previously had entirely separate
implementations for rel & rela style relocs, which unnecessarily
duplicates a whole lot of code. Unify the implementations of both types
of reloc, sharing the bulk of the code.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15832/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 351b0940
......@@ -47,8 +47,8 @@ typedef struct {
#define Elf_Mips_Rel Elf32_Rel
#define Elf_Mips_Rela Elf32_Rela
#define ELF_MIPS_R_SYM(rel) ELF32_R_SYM(rel.r_info)
#define ELF_MIPS_R_TYPE(rel) ELF32_R_TYPE(rel.r_info)
#define ELF_MIPS_R_SYM(rel) ELF32_R_SYM((rel).r_info)
#define ELF_MIPS_R_TYPE(rel) ELF32_R_TYPE((rel).r_info)
#endif
......@@ -65,8 +65,8 @@ typedef struct {
#define Elf_Mips_Rel Elf64_Mips_Rel
#define Elf_Mips_Rela Elf64_Mips_Rela
#define ELF_MIPS_R_SYM(rel) (rel.r_sym)
#define ELF_MIPS_R_TYPE(rel) (rel.r_type)
#define ELF_MIPS_R_SYM(rel) ((rel).r_sym)
#define ELF_MIPS_R_TYPE(rel) ((rel).r_type)
#endif
......
......@@ -31,7 +31,6 @@ obj-$(CONFIG_SYNC_R4K) += sync-r4k.o
obj-$(CONFIG_DEBUG_FS) += segment.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_MODULES_USE_ELF_RELA) += module-rela.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o
......
/*
* 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;
}
......@@ -53,22 +53,25 @@ void *module_alloc(unsigned long size)
}
#endif
int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_none(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return 0;
}
static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_32(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
*location += v;
*location = base + v;
return 0;
}
static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_26(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (v % 4) {
pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
pr_err("module %s: dangerous R_MIPS_26 relocation\n",
me->name);
return -ENOEXEC;
}
......@@ -80,15 +83,22 @@ static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
}
*location = (*location & ~0x03ffffff) |
((*location + (v >> 2)) & 0x03ffffff);
((base + (v >> 2)) & 0x03ffffff);
return 0;
}
static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_hi16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
struct mips_hi16 *n;
if (rela) {
*location = (*location & 0xffff0000) |
((((long long) v + 0x8000LL) >> 16) & 0xffff);
return 0;
}
/*
* 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
......@@ -117,12 +127,18 @@ static void free_relocation_chain(struct mips_hi16 *l)
}
}
static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_lo16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
unsigned long insnlo = *location;
unsigned long insnlo = base;
struct mips_hi16 *l;
Elf_Addr val, vallo;
if (rela) {
*location = (*location & 0xffff0000) | (v & 0xffff);
return 0;
}
/* Sign extend the addend we extract from the lo insn. */
vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
......@@ -178,26 +194,26 @@ static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
free_relocation_chain(l);
me->arch.r_mips_hi16_list = NULL;
pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);
pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name);
return -ENOEXEC;
}
static int apply_r_mips_pc_rel(struct module *me, u32 *location, Elf_Addr v,
unsigned bits)
static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,
Elf_Addr v, unsigned int 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 REL relocation\n",
pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
me->name, bits);
return -ENOEXEC;
}
/* retrieve & sign extend implicit addend */
offset = *location & mask;
/* retrieve & sign extend implicit addend if any */
offset = base & mask;
offset |= (offset & BIT(bits - 1)) ? ~mask : 0;
offset += ((long)v - (long)location) >> 2;
......@@ -214,56 +230,121 @@ static int apply_r_mips_pc_rel(struct module *me, u32 *location, Elf_Addr v,
return 0;
}
static int apply_r_mips_pc16_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_pc16(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc_rel(me, location, v, 16);
return apply_r_mips_pc(me, location, base, v, 16);
}
static int apply_r_mips_pc21_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_pc21(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc_rel(me, location, v, 21);
return apply_r_mips_pc(me, location, base, v, 21);
}
static int apply_r_mips_pc26_rel(struct module *me, u32 *location, Elf_Addr v)
static int apply_r_mips_pc26(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
return apply_r_mips_pc_rel(me, location, v, 26);
return apply_r_mips_pc(me, location, base, v, 26);
}
static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
Elf_Addr v) = {
static int apply_r_mips_64(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*(Elf_Addr *)location = v;
return 0;
}
static int apply_r_mips_higher(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*location = (*location & 0xffff0000) |
((((long long)v + 0x80008000LL) >> 32) & 0xffff);
return 0;
}
static int apply_r_mips_highest(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela)
{
if (WARN_ON(!rela))
return -EINVAL;
*location = (*location & 0xffff0000) |
((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
return 0;
}
/**
* reloc_handler() - Apply a particular relocation to a module
* @me: the module to apply the reloc to
* @location: the address at which the reloc is to be applied
* @base: the existing value at location for REL-style; 0 for RELA-style
* @v: the value of the reloc, with addend for RELA-style
*
* Each implemented reloc_handler function applies a particular type of
* relocation to the module @me. Relocs that may be found in either REL or RELA
* variants can be handled by making use of the @base & @v parameters which are
* set to values which abstract the difference away from the particular reloc
* implementations.
*
* Return: 0 upon success, else -ERRNO
*/
typedef int (*reloc_handler)(struct module *me, u32 *location,
u32 base, Elf_Addr v, bool rela);
/* The handlers for known reloc types */
static reloc_handler reloc_handlers[] = {
[R_MIPS_NONE] = apply_r_mips_none,
[R_MIPS_32] = apply_r_mips_32_rel,
[R_MIPS_26] = apply_r_mips_26_rel,
[R_MIPS_HI16] = apply_r_mips_hi16_rel,
[R_MIPS_LO16] = apply_r_mips_lo16_rel,
[R_MIPS_PC16] = apply_r_mips_pc16_rel,
[R_MIPS_PC21_S2] = apply_r_mips_pc21_rel,
[R_MIPS_PC26_S2] = apply_r_mips_pc26_rel,
[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,
[R_MIPS_PC16] = apply_r_mips_pc16,
[R_MIPS_64] = apply_r_mips_64,
[R_MIPS_HIGHER] = apply_r_mips_higher,
[R_MIPS_HIGHEST] = apply_r_mips_highest,
[R_MIPS_PC21_S2] = apply_r_mips_pc21,
[R_MIPS_PC26_S2] = apply_r_mips_pc26,
};
int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me, bool rela)
{
Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
int (*handler)(struct module *me, u32 *location, Elf_Addr v);
union {
Elf_Mips_Rel *rel;
Elf_Mips_Rela *rela;
} r;
reloc_handler handler;
Elf_Sym *sym;
u32 *location;
u32 *location, base;
unsigned int i, type;
Elf_Addr v;
int err = 0;
size_t reloc_sz;
pr_debug("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
r.rel = (void *)sechdrs[relsec].sh_addr;
reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);
me->arch.r_mips_hi16_list = NULL;
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
/* This is where to make the change */
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
+ r.rel->r_offset;
/* This is the symbol it is referring to */
sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ ELF_MIPS_R_SYM(rel[i]);
+ ELF_MIPS_R_SYM(*r.rel);
if (sym->st_value >= -MAX_ERRNO) {
/* Ignore unresolved weak symbol */
if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
......@@ -274,10 +355,9 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
goto out;
}
type = ELF_MIPS_R_TYPE(rel[i]);
if (type < ARRAY_SIZE(reloc_handlers_rel))
handler = reloc_handlers_rel[type];
type = ELF_MIPS_R_TYPE(*r.rel);
if (type < ARRAY_SIZE(reloc_handlers))
handler = reloc_handlers[type];
else
handler = NULL;
......@@ -288,8 +368,17 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
goto out;
}
v = sym->st_value;
err = handler(me, location, v);
if (rela) {
v = sym->st_value + r.rela->r_addend;
base = 0;
r.rela = &r.rela[1];
} else {
v = sym->st_value;
base = *location;
r.rel = &r.rel[1];
}
err = handler(me, location, base, v, rela);
if (err)
goto out;
}
......@@ -312,6 +401,22 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
return err;
}
int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
{
return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
}
#ifdef CONFIG_MODULES_USE_ELF_RELA
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *me)
{
return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
}
#endif /* CONFIG_MODULES_USE_ELF_RELA */
/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_dbetables(unsigned long addr)
{
......
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