383 lines
10 KiB
C
383 lines
10 KiB
C
/* Kernel module help for PPC.
|
|
Copyright (C) 2001 Rusty Russell.
|
|
|
|
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
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/moduleloader.h>
|
|
#include <linux/elf.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/string.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/cache.h>
|
|
#include <linux/bug.h>
|
|
#include <linux/sort.h>
|
|
|
|
#include "setup.h"
|
|
|
|
#if 0
|
|
#define DEBUGP printk
|
|
#else
|
|
#define DEBUGP(fmt , ...)
|
|
#endif
|
|
|
|
LIST_HEAD(module_bug_list);
|
|
|
|
void *module_alloc(unsigned long size)
|
|
{
|
|
if (size == 0)
|
|
return NULL;
|
|
return vmalloc(size);
|
|
}
|
|
|
|
/* Free memory returned from module_alloc */
|
|
void module_free(struct module *mod, void *module_region)
|
|
{
|
|
vfree(module_region);
|
|
/* FIXME: If module_region == mod->init_region, trim exception
|
|
table entries. */
|
|
}
|
|
|
|
/* Count how many different relocations (different symbol, different
|
|
addend) */
|
|
static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
|
|
{
|
|
unsigned int i, r_info, r_addend, _count_relocs;
|
|
|
|
_count_relocs = 0;
|
|
r_info = 0;
|
|
r_addend = 0;
|
|
for (i = 0; i < num; i++)
|
|
/* Only count 24-bit relocs, others don't need stubs */
|
|
if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
|
|
(r_info != ELF32_R_SYM(rela[i].r_info) ||
|
|
r_addend != rela[i].r_addend)) {
|
|
_count_relocs++;
|
|
r_info = ELF32_R_SYM(rela[i].r_info);
|
|
r_addend = rela[i].r_addend;
|
|
}
|
|
|
|
return _count_relocs;
|
|
}
|
|
|
|
static int relacmp(const void *_x, const void *_y)
|
|
{
|
|
const Elf32_Rela *x, *y;
|
|
|
|
y = (Elf32_Rela *)_x;
|
|
x = (Elf32_Rela *)_y;
|
|
|
|
/* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
|
|
* make the comparison cheaper/faster. It won't affect the sorting or
|
|
* the counting algorithms' performance
|
|
*/
|
|
if (x->r_info < y->r_info)
|
|
return -1;
|
|
else if (x->r_info > y->r_info)
|
|
return 1;
|
|
else if (x->r_addend < y->r_addend)
|
|
return -1;
|
|
else if (x->r_addend > y->r_addend)
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
static void relaswap(void *_x, void *_y, int size)
|
|
{
|
|
uint32_t *x, *y, tmp;
|
|
int i;
|
|
|
|
y = (uint32_t *)_x;
|
|
x = (uint32_t *)_y;
|
|
|
|
for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
|
|
tmp = x[i];
|
|
x[i] = y[i];
|
|
y[i] = tmp;
|
|
}
|
|
}
|
|
|
|
/* Get the potential trampolines size required of the init and
|
|
non-init sections */
|
|
static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
|
|
const Elf32_Shdr *sechdrs,
|
|
const char *secstrings,
|
|
int is_init)
|
|
{
|
|
unsigned long ret = 0;
|
|
unsigned i;
|
|
|
|
/* Everything marked ALLOC (this includes the exported
|
|
symbols) */
|
|
for (i = 1; i < hdr->e_shnum; i++) {
|
|
/* If it's called *.init*, and we're not init, we're
|
|
not interested */
|
|
if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
|
|
!= is_init)
|
|
continue;
|
|
|
|
/* We don't want to look at debug sections. */
|
|
if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
|
|
continue;
|
|
|
|
if (sechdrs[i].sh_type == SHT_RELA) {
|
|
DEBUGP("Found relocations in section %u\n", i);
|
|
DEBUGP("Ptr: %p. Number: %u\n",
|
|
(void *)hdr + sechdrs[i].sh_offset,
|
|
sechdrs[i].sh_size / sizeof(Elf32_Rela));
|
|
|
|
/* Sort the relocation information based on a symbol and
|
|
* addend key. This is a stable O(n*log n) complexity
|
|
* alogrithm but it will reduce the complexity of
|
|
* count_relocs() to linear complexity O(n)
|
|
*/
|
|
sort((void *)hdr + sechdrs[i].sh_offset,
|
|
sechdrs[i].sh_size / sizeof(Elf32_Rela),
|
|
sizeof(Elf32_Rela), relacmp, relaswap);
|
|
|
|
ret += count_relocs((void *)hdr
|
|
+ sechdrs[i].sh_offset,
|
|
sechdrs[i].sh_size
|
|
/ sizeof(Elf32_Rela))
|
|
* sizeof(struct ppc_plt_entry);
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int module_frob_arch_sections(Elf32_Ehdr *hdr,
|
|
Elf32_Shdr *sechdrs,
|
|
char *secstrings,
|
|
struct module *me)
|
|
{
|
|
unsigned int i;
|
|
|
|
/* Find .plt and .init.plt sections */
|
|
for (i = 0; i < hdr->e_shnum; i++) {
|
|
if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
|
|
me->arch.init_plt_section = i;
|
|
else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
|
|
me->arch.core_plt_section = i;
|
|
}
|
|
if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
|
|
printk("Module doesn't contain .plt or .init.plt sections.\n");
|
|
return -ENOEXEC;
|
|
}
|
|
|
|
/* Override their sizes */
|
|
sechdrs[me->arch.core_plt_section].sh_size
|
|
= get_plt_size(hdr, sechdrs, secstrings, 0);
|
|
sechdrs[me->arch.init_plt_section].sh_size
|
|
= get_plt_size(hdr, sechdrs, secstrings, 1);
|
|
return 0;
|
|
}
|
|
|
|
int apply_relocate(Elf32_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *module)
|
|
{
|
|
printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
|
|
module->name);
|
|
return -ENOEXEC;
|
|
}
|
|
|
|
static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
|
|
{
|
|
if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
|
|
&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/* Set up a trampoline in the PLT to bounce us to the distant function */
|
|
static uint32_t do_plt_call(void *location,
|
|
Elf32_Addr val,
|
|
Elf32_Shdr *sechdrs,
|
|
struct module *mod)
|
|
{
|
|
struct ppc_plt_entry *entry;
|
|
|
|
DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
|
|
/* Init, or core PLT? */
|
|
if (location >= mod->module_core
|
|
&& location < mod->module_core + mod->core_size)
|
|
entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
|
|
else
|
|
entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
|
|
|
|
/* Find this entry, or if that fails, the next avail. entry */
|
|
while (entry->jump[0]) {
|
|
if (entry_matches(entry, val)) return (uint32_t)entry;
|
|
entry++;
|
|
}
|
|
|
|
/* Stolen from Paul Mackerras as well... */
|
|
entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
|
|
entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
|
|
entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
|
|
entry->jump[3] = 0x4e800420; /* bctr */
|
|
|
|
DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
|
|
return (uint32_t)entry;
|
|
}
|
|
|
|
int apply_relocate_add(Elf32_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *module)
|
|
{
|
|
unsigned int i;
|
|
Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
|
|
Elf32_Sym *sym;
|
|
uint32_t *location;
|
|
uint32_t value;
|
|
|
|
DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
|
|
sechdrs[relsec].sh_info);
|
|
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
|
|
/* This is where to make the change */
|
|
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
|
|
+ rela[i].r_offset;
|
|
/* 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(rela[i].r_info);
|
|
/* `Everything is relative'. */
|
|
value = sym->st_value + rela[i].r_addend;
|
|
|
|
switch (ELF32_R_TYPE(rela[i].r_info)) {
|
|
case R_PPC_ADDR32:
|
|
/* Simply set it */
|
|
*(uint32_t *)location = value;
|
|
break;
|
|
|
|
case R_PPC_ADDR16_LO:
|
|
/* Low half of the symbol */
|
|
*(uint16_t *)location = value;
|
|
break;
|
|
|
|
case R_PPC_ADDR16_HI:
|
|
/* Higher half of the symbol */
|
|
*(uint16_t *)location = (value >> 16);
|
|
break;
|
|
|
|
case R_PPC_ADDR16_HA:
|
|
/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
|
|
(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
|
|
This is the same, only sane.
|
|
*/
|
|
*(uint16_t *)location = (value + 0x8000) >> 16;
|
|
break;
|
|
|
|
case R_PPC_REL24:
|
|
if ((int)(value - (uint32_t)location) < -0x02000000
|
|
|| (int)(value - (uint32_t)location) >= 0x02000000)
|
|
value = do_plt_call(location, value,
|
|
sechdrs, module);
|
|
|
|
/* Only replace bits 2 through 26 */
|
|
DEBUGP("REL24 value = %08X. location = %08X\n",
|
|
value, (uint32_t)location);
|
|
DEBUGP("Location before: %08X.\n",
|
|
*(uint32_t *)location);
|
|
*(uint32_t *)location
|
|
= (*(uint32_t *)location & ~0x03fffffc)
|
|
| ((value - (uint32_t)location)
|
|
& 0x03fffffc);
|
|
DEBUGP("Location after: %08X.\n",
|
|
*(uint32_t *)location);
|
|
DEBUGP("ie. jump to %08X+%08X = %08X\n",
|
|
*(uint32_t *)location & 0x03fffffc,
|
|
(uint32_t)location,
|
|
(*(uint32_t *)location & 0x03fffffc)
|
|
+ (uint32_t)location);
|
|
break;
|
|
|
|
case R_PPC_REL32:
|
|
/* 32-bit relative jump. */
|
|
*(uint32_t *)location = value - (uint32_t)location;
|
|
break;
|
|
|
|
default:
|
|
printk("%s: unknown ADD relocation: %u\n",
|
|
module->name,
|
|
ELF32_R_TYPE(rela[i].r_info));
|
|
return -ENOEXEC;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
|
|
const Elf_Shdr *sechdrs,
|
|
const char *name)
|
|
{
|
|
char *secstrings;
|
|
unsigned int i;
|
|
|
|
secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
|
|
for (i = 1; i < hdr->e_shnum; i++)
|
|
if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
|
|
return &sechdrs[i];
|
|
return NULL;
|
|
}
|
|
|
|
int module_finalize(const Elf_Ehdr *hdr,
|
|
const Elf_Shdr *sechdrs,
|
|
struct module *me)
|
|
{
|
|
const Elf_Shdr *sect;
|
|
int err;
|
|
|
|
err = module_bug_finalize(hdr, sechdrs, me);
|
|
if (err) /* never true, currently */
|
|
return err;
|
|
|
|
/* Apply feature fixups */
|
|
sect = find_section(hdr, sechdrs, "__ftr_fixup");
|
|
if (sect != NULL)
|
|
do_feature_fixups(cur_cpu_spec->cpu_features,
|
|
(void *)sect->sh_addr,
|
|
(void *)sect->sh_addr + sect->sh_size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void module_arch_cleanup(struct module *mod)
|
|
{
|
|
module_bug_cleanup(mod);
|
|
}
|
|
|
|
struct bug_entry *module_find_bug(unsigned long bugaddr)
|
|
{
|
|
struct mod_arch_specific *mod;
|
|
unsigned int i;
|
|
struct bug_entry *bug;
|
|
|
|
list_for_each_entry(mod, &module_bug_list, bug_list) {
|
|
bug = mod->bug_table;
|
|
for (i = 0; i < mod->num_bugs; ++i, ++bug)
|
|
if (bugaddr == bug->bug_addr)
|
|
return bug;
|
|
}
|
|
return NULL;
|
|
}
|