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-rw-r--r--arch/x86/kernel/alternative.c26
-rw-r--r--kernel/extable.c2
2 files changed, 15 insertions, 13 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3344d3382e91..dbaf14d69ebd 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -442,7 +442,6 @@ static void alternatives_smp_lock(const s32 *start, const s32 *end,
{
const s32 *poff;
- mutex_lock(&text_mutex);
for (poff = start; poff < end; poff++) {
u8 *ptr = (u8 *)poff + *poff;
@@ -452,7 +451,6 @@ static void alternatives_smp_lock(const s32 *start, const s32 *end,
if (*ptr == 0x3e)
text_poke(ptr, ((unsigned char []){0xf0}), 1);
}
- mutex_unlock(&text_mutex);
}
static void alternatives_smp_unlock(const s32 *start, const s32 *end,
@@ -460,7 +458,6 @@ static void alternatives_smp_unlock(const s32 *start, const s32 *end,
{
const s32 *poff;
- mutex_lock(&text_mutex);
for (poff = start; poff < end; poff++) {
u8 *ptr = (u8 *)poff + *poff;
@@ -470,7 +467,6 @@ static void alternatives_smp_unlock(const s32 *start, const s32 *end,
if (*ptr == 0xf0)
text_poke(ptr, ((unsigned char []){0x3E}), 1);
}
- mutex_unlock(&text_mutex);
}
struct smp_alt_module {
@@ -489,8 +485,7 @@ struct smp_alt_module {
struct list_head next;
};
static LIST_HEAD(smp_alt_modules);
-static DEFINE_MUTEX(smp_alt);
-static bool uniproc_patched = false; /* protected by smp_alt */
+static bool uniproc_patched = false; /* protected by text_mutex */
void __init_or_module alternatives_smp_module_add(struct module *mod,
char *name,
@@ -499,7 +494,7 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
{
struct smp_alt_module *smp;
- mutex_lock(&smp_alt);
+ mutex_lock(&text_mutex);
if (!uniproc_patched)
goto unlock;
@@ -526,14 +521,14 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
smp_unlock:
alternatives_smp_unlock(locks, locks_end, text, text_end);
unlock:
- mutex_unlock(&smp_alt);
+ mutex_unlock(&text_mutex);
}
void __init_or_module alternatives_smp_module_del(struct module *mod)
{
struct smp_alt_module *item;
- mutex_lock(&smp_alt);
+ mutex_lock(&text_mutex);
list_for_each_entry(item, &smp_alt_modules, next) {
if (mod != item->mod)
continue;
@@ -541,7 +536,7 @@ void __init_or_module alternatives_smp_module_del(struct module *mod)
kfree(item);
break;
}
- mutex_unlock(&smp_alt);
+ mutex_unlock(&text_mutex);
}
void alternatives_enable_smp(void)
@@ -551,7 +546,7 @@ void alternatives_enable_smp(void)
/* Why bother if there are no other CPUs? */
BUG_ON(num_possible_cpus() == 1);
- mutex_lock(&smp_alt);
+ mutex_lock(&text_mutex);
if (uniproc_patched) {
pr_info("switching to SMP code\n");
@@ -563,10 +558,13 @@ void alternatives_enable_smp(void)
mod->text, mod->text_end);
uniproc_patched = false;
}
- mutex_unlock(&smp_alt);
+ mutex_unlock(&text_mutex);
}
-/* Return 1 if the address range is reserved for smp-alternatives */
+/*
+ * Return 1 if the address range is reserved for SMP-alternatives.
+ * Must hold text_mutex.
+ */
int alternatives_text_reserved(void *start, void *end)
{
struct smp_alt_module *mod;
@@ -574,6 +572,8 @@ int alternatives_text_reserved(void *start, void *end)
u8 *text_start = start;
u8 *text_end = end;
+ lockdep_assert_held(&text_mutex);
+
list_for_each_entry(mod, &smp_alt_modules, next) {
if (mod->text > text_end || mod->text_end < text_start)
continue;
diff --git a/kernel/extable.c b/kernel/extable.c
index 9aa1cc41ecf7..a17fdb63dc3e 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -31,6 +31,8 @@
* mutex protecting text section modification (dynamic code patching).
* some users need to sleep (allocating memory...) while they hold this lock.
*
+ * Note: Also protects SMP-alternatives modification on x86.
+ *
* NOT exported to modules - patching kernel text is a really delicate matter.
*/
DEFINE_MUTEX(text_mutex);