mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-16 14:02:10 +00:00
95bcd683fb
Some archs do not need to do anything special for jump labels on startup (like MIPS). This patch adds a weak function stub for arch_jump_label_text_poke_early(); Cc: Jason Baron <jbaron@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: David Daney <ddaney@caviumnetworks.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <1286218615-24011-2-git-send-email-ddaney@caviumnetworks.com> LKML-Reference: <20101015201037.703989993@goodmis.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
485 lines
11 KiB
C
485 lines
11 KiB
C
/*
|
|
* jump label support
|
|
*
|
|
* Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
|
|
*
|
|
*/
|
|
#include <linux/jump_label.h>
|
|
#include <linux/memory.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/module.h>
|
|
#include <linux/list.h>
|
|
#include <linux/jhash.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sort.h>
|
|
#include <linux/err.h>
|
|
|
|
#ifdef HAVE_JUMP_LABEL
|
|
|
|
#define JUMP_LABEL_HASH_BITS 6
|
|
#define JUMP_LABEL_TABLE_SIZE (1 << JUMP_LABEL_HASH_BITS)
|
|
static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE];
|
|
|
|
/* mutex to protect coming/going of the the jump_label table */
|
|
static DEFINE_MUTEX(jump_label_mutex);
|
|
|
|
struct jump_label_entry {
|
|
struct hlist_node hlist;
|
|
struct jump_entry *table;
|
|
int nr_entries;
|
|
/* hang modules off here */
|
|
struct hlist_head modules;
|
|
unsigned long key;
|
|
};
|
|
|
|
struct jump_label_module_entry {
|
|
struct hlist_node hlist;
|
|
struct jump_entry *table;
|
|
int nr_entries;
|
|
struct module *mod;
|
|
};
|
|
|
|
void jump_label_lock(void)
|
|
{
|
|
mutex_lock(&jump_label_mutex);
|
|
}
|
|
|
|
void jump_label_unlock(void)
|
|
{
|
|
mutex_unlock(&jump_label_mutex);
|
|
}
|
|
|
|
static int jump_label_cmp(const void *a, const void *b)
|
|
{
|
|
const struct jump_entry *jea = a;
|
|
const struct jump_entry *jeb = b;
|
|
|
|
if (jea->key < jeb->key)
|
|
return -1;
|
|
|
|
if (jea->key > jeb->key)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
sort_jump_label_entries(struct jump_entry *start, struct jump_entry *stop)
|
|
{
|
|
unsigned long size;
|
|
|
|
size = (((unsigned long)stop - (unsigned long)start)
|
|
/ sizeof(struct jump_entry));
|
|
sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
|
|
}
|
|
|
|
static struct jump_label_entry *get_jump_label_entry(jump_label_t key)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct jump_label_entry *e;
|
|
u32 hash = jhash((void *)&key, sizeof(jump_label_t), 0);
|
|
|
|
head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
|
|
hlist_for_each_entry(e, node, head, hlist) {
|
|
if (key == e->key)
|
|
return e;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static struct jump_label_entry *
|
|
add_jump_label_entry(jump_label_t key, int nr_entries, struct jump_entry *table)
|
|
{
|
|
struct hlist_head *head;
|
|
struct jump_label_entry *e;
|
|
u32 hash;
|
|
|
|
e = get_jump_label_entry(key);
|
|
if (e)
|
|
return ERR_PTR(-EEXIST);
|
|
|
|
e = kmalloc(sizeof(struct jump_label_entry), GFP_KERNEL);
|
|
if (!e)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
hash = jhash((void *)&key, sizeof(jump_label_t), 0);
|
|
head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
|
|
e->key = key;
|
|
e->table = table;
|
|
e->nr_entries = nr_entries;
|
|
INIT_HLIST_HEAD(&(e->modules));
|
|
hlist_add_head(&e->hlist, head);
|
|
return e;
|
|
}
|
|
|
|
static int
|
|
build_jump_label_hashtable(struct jump_entry *start, struct jump_entry *stop)
|
|
{
|
|
struct jump_entry *iter, *iter_begin;
|
|
struct jump_label_entry *entry;
|
|
int count;
|
|
|
|
sort_jump_label_entries(start, stop);
|
|
iter = start;
|
|
while (iter < stop) {
|
|
entry = get_jump_label_entry(iter->key);
|
|
if (!entry) {
|
|
iter_begin = iter;
|
|
count = 0;
|
|
while ((iter < stop) &&
|
|
(iter->key == iter_begin->key)) {
|
|
iter++;
|
|
count++;
|
|
}
|
|
entry = add_jump_label_entry(iter_begin->key,
|
|
count, iter_begin);
|
|
if (IS_ERR(entry))
|
|
return PTR_ERR(entry);
|
|
} else {
|
|
WARN_ONCE(1, KERN_ERR "build_jump_hashtable: unexpected entry!\n");
|
|
return -1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/***
|
|
* jump_label_update - update jump label text
|
|
* @key - key value associated with a a jump label
|
|
* @type - enum set to JUMP_LABEL_ENABLE or JUMP_LABEL_DISABLE
|
|
*
|
|
* Will enable/disable the jump for jump label @key, depending on the
|
|
* value of @type.
|
|
*
|
|
*/
|
|
|
|
void jump_label_update(unsigned long key, enum jump_label_type type)
|
|
{
|
|
struct jump_entry *iter;
|
|
struct jump_label_entry *entry;
|
|
struct hlist_node *module_node;
|
|
struct jump_label_module_entry *e_module;
|
|
int count;
|
|
|
|
jump_label_lock();
|
|
entry = get_jump_label_entry((jump_label_t)key);
|
|
if (entry) {
|
|
count = entry->nr_entries;
|
|
iter = entry->table;
|
|
while (count--) {
|
|
if (kernel_text_address(iter->code))
|
|
arch_jump_label_transform(iter, type);
|
|
iter++;
|
|
}
|
|
/* eanble/disable jump labels in modules */
|
|
hlist_for_each_entry(e_module, module_node, &(entry->modules),
|
|
hlist) {
|
|
count = e_module->nr_entries;
|
|
iter = e_module->table;
|
|
while (count--) {
|
|
if (iter->key &&
|
|
kernel_text_address(iter->code))
|
|
arch_jump_label_transform(iter, type);
|
|
iter++;
|
|
}
|
|
}
|
|
}
|
|
jump_label_unlock();
|
|
}
|
|
|
|
static int addr_conflict(struct jump_entry *entry, void *start, void *end)
|
|
{
|
|
if (entry->code <= (unsigned long)end &&
|
|
entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
|
|
static int module_conflict(void *start, void *end)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node, *node_next, *module_node, *module_node_next;
|
|
struct jump_label_entry *e;
|
|
struct jump_label_module_entry *e_module;
|
|
struct jump_entry *iter;
|
|
int i, count;
|
|
int conflict = 0;
|
|
|
|
for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
|
|
head = &jump_label_table[i];
|
|
hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
|
|
hlist_for_each_entry_safe(e_module, module_node,
|
|
module_node_next,
|
|
&(e->modules), hlist) {
|
|
count = e_module->nr_entries;
|
|
iter = e_module->table;
|
|
while (count--) {
|
|
if (addr_conflict(iter, start, end)) {
|
|
conflict = 1;
|
|
goto out;
|
|
}
|
|
iter++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
out:
|
|
return conflict;
|
|
}
|
|
|
|
#endif
|
|
|
|
/***
|
|
* jump_label_text_reserved - check if addr range is reserved
|
|
* @start: start text addr
|
|
* @end: end text addr
|
|
*
|
|
* checks if the text addr located between @start and @end
|
|
* overlaps with any of the jump label patch addresses. Code
|
|
* that wants to modify kernel text should first verify that
|
|
* it does not overlap with any of the jump label addresses.
|
|
* Caller must hold jump_label_mutex.
|
|
*
|
|
* returns 1 if there is an overlap, 0 otherwise
|
|
*/
|
|
int jump_label_text_reserved(void *start, void *end)
|
|
{
|
|
struct jump_entry *iter;
|
|
struct jump_entry *iter_start = __start___jump_table;
|
|
struct jump_entry *iter_stop = __start___jump_table;
|
|
int conflict = 0;
|
|
|
|
iter = iter_start;
|
|
while (iter < iter_stop) {
|
|
if (addr_conflict(iter, start, end)) {
|
|
conflict = 1;
|
|
goto out;
|
|
}
|
|
iter++;
|
|
}
|
|
|
|
/* now check modules */
|
|
#ifdef CONFIG_MODULES
|
|
conflict = module_conflict(start, end);
|
|
#endif
|
|
out:
|
|
return conflict;
|
|
}
|
|
|
|
/*
|
|
* Not all archs need this.
|
|
*/
|
|
void __weak arch_jump_label_text_poke_early(jump_label_t addr)
|
|
{
|
|
}
|
|
|
|
static __init int init_jump_label(void)
|
|
{
|
|
int ret;
|
|
struct jump_entry *iter_start = __start___jump_table;
|
|
struct jump_entry *iter_stop = __stop___jump_table;
|
|
struct jump_entry *iter;
|
|
|
|
jump_label_lock();
|
|
ret = build_jump_label_hashtable(__start___jump_table,
|
|
__stop___jump_table);
|
|
iter = iter_start;
|
|
while (iter < iter_stop) {
|
|
arch_jump_label_text_poke_early(iter->code);
|
|
iter++;
|
|
}
|
|
jump_label_unlock();
|
|
return ret;
|
|
}
|
|
early_initcall(init_jump_label);
|
|
|
|
#ifdef CONFIG_MODULES
|
|
|
|
static struct jump_label_module_entry *
|
|
add_jump_label_module_entry(struct jump_label_entry *entry,
|
|
struct jump_entry *iter_begin,
|
|
int count, struct module *mod)
|
|
{
|
|
struct jump_label_module_entry *e;
|
|
|
|
e = kmalloc(sizeof(struct jump_label_module_entry), GFP_KERNEL);
|
|
if (!e)
|
|
return ERR_PTR(-ENOMEM);
|
|
e->mod = mod;
|
|
e->nr_entries = count;
|
|
e->table = iter_begin;
|
|
hlist_add_head(&e->hlist, &entry->modules);
|
|
return e;
|
|
}
|
|
|
|
static int add_jump_label_module(struct module *mod)
|
|
{
|
|
struct jump_entry *iter, *iter_begin;
|
|
struct jump_label_entry *entry;
|
|
struct jump_label_module_entry *module_entry;
|
|
int count;
|
|
|
|
/* if the module doesn't have jump label entries, just return */
|
|
if (!mod->num_jump_entries)
|
|
return 0;
|
|
|
|
sort_jump_label_entries(mod->jump_entries,
|
|
mod->jump_entries + mod->num_jump_entries);
|
|
iter = mod->jump_entries;
|
|
while (iter < mod->jump_entries + mod->num_jump_entries) {
|
|
entry = get_jump_label_entry(iter->key);
|
|
iter_begin = iter;
|
|
count = 0;
|
|
while ((iter < mod->jump_entries + mod->num_jump_entries) &&
|
|
(iter->key == iter_begin->key)) {
|
|
iter++;
|
|
count++;
|
|
}
|
|
if (!entry) {
|
|
entry = add_jump_label_entry(iter_begin->key, 0, NULL);
|
|
if (IS_ERR(entry))
|
|
return PTR_ERR(entry);
|
|
}
|
|
module_entry = add_jump_label_module_entry(entry, iter_begin,
|
|
count, mod);
|
|
if (IS_ERR(module_entry))
|
|
return PTR_ERR(module_entry);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void remove_jump_label_module(struct module *mod)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node, *node_next, *module_node, *module_node_next;
|
|
struct jump_label_entry *e;
|
|
struct jump_label_module_entry *e_module;
|
|
int i;
|
|
|
|
/* if the module doesn't have jump label entries, just return */
|
|
if (!mod->num_jump_entries)
|
|
return;
|
|
|
|
for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
|
|
head = &jump_label_table[i];
|
|
hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
|
|
hlist_for_each_entry_safe(e_module, module_node,
|
|
module_node_next,
|
|
&(e->modules), hlist) {
|
|
if (e_module->mod == mod) {
|
|
hlist_del(&e_module->hlist);
|
|
kfree(e_module);
|
|
}
|
|
}
|
|
if (hlist_empty(&e->modules) && (e->nr_entries == 0)) {
|
|
hlist_del(&e->hlist);
|
|
kfree(e);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void remove_jump_label_module_init(struct module *mod)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node, *node_next, *module_node, *module_node_next;
|
|
struct jump_label_entry *e;
|
|
struct jump_label_module_entry *e_module;
|
|
struct jump_entry *iter;
|
|
int i, count;
|
|
|
|
/* if the module doesn't have jump label entries, just return */
|
|
if (!mod->num_jump_entries)
|
|
return;
|
|
|
|
for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
|
|
head = &jump_label_table[i];
|
|
hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
|
|
hlist_for_each_entry_safe(e_module, module_node,
|
|
module_node_next,
|
|
&(e->modules), hlist) {
|
|
if (e_module->mod != mod)
|
|
continue;
|
|
count = e_module->nr_entries;
|
|
iter = e_module->table;
|
|
while (count--) {
|
|
if (within_module_init(iter->code, mod))
|
|
iter->key = 0;
|
|
iter++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static int
|
|
jump_label_module_notify(struct notifier_block *self, unsigned long val,
|
|
void *data)
|
|
{
|
|
struct module *mod = data;
|
|
int ret = 0;
|
|
|
|
switch (val) {
|
|
case MODULE_STATE_COMING:
|
|
jump_label_lock();
|
|
ret = add_jump_label_module(mod);
|
|
if (ret)
|
|
remove_jump_label_module(mod);
|
|
jump_label_unlock();
|
|
break;
|
|
case MODULE_STATE_GOING:
|
|
jump_label_lock();
|
|
remove_jump_label_module(mod);
|
|
jump_label_unlock();
|
|
break;
|
|
case MODULE_STATE_LIVE:
|
|
jump_label_lock();
|
|
remove_jump_label_module_init(mod);
|
|
jump_label_unlock();
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/***
|
|
* apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
|
|
* @mod: module to patch
|
|
*
|
|
* Allow for run-time selection of the optimal nops. Before the module
|
|
* loads patch these with arch_get_jump_label_nop(), which is specified by
|
|
* the arch specific jump label code.
|
|
*/
|
|
void jump_label_apply_nops(struct module *mod)
|
|
{
|
|
struct jump_entry *iter;
|
|
|
|
/* if the module doesn't have jump label entries, just return */
|
|
if (!mod->num_jump_entries)
|
|
return;
|
|
|
|
iter = mod->jump_entries;
|
|
while (iter < mod->jump_entries + mod->num_jump_entries) {
|
|
arch_jump_label_text_poke_early(iter->code);
|
|
iter++;
|
|
}
|
|
}
|
|
|
|
struct notifier_block jump_label_module_nb = {
|
|
.notifier_call = jump_label_module_notify,
|
|
.priority = 0,
|
|
};
|
|
|
|
static __init int init_jump_label_module(void)
|
|
{
|
|
return register_module_notifier(&jump_label_module_nb);
|
|
}
|
|
early_initcall(init_jump_label_module);
|
|
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
#endif
|