Merge tag 'core-static_call-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull static call support from Ingo Molnar:
 "This introduces static_call(), which is the idea of static_branch()
  applied to indirect function calls. Remove a data load (indirection)
  by modifying the text.

  They give the flexibility of function pointers, but with better
  performance. (This is especially important for cases where retpolines
  would otherwise be used, as retpolines can be pretty slow.)

  API overview:

      DECLARE_STATIC_CALL(name, func);
      DEFINE_STATIC_CALL(name, func);
      DEFINE_STATIC_CALL_NULL(name, typename);

      static_call(name)(args...);
      static_call_cond(name)(args...);
      static_call_update(name, func);

  x86 is supported via text patching, otherwise basic indirect calls are
  used, with function pointers.

  There's a second variant using inline code patching, inspired by
  jump-labels, implemented on x86 as well.

  The new APIs are utilized in the x86 perf code, a heavy user of
  function pointers, where static calls speed up the PMU handler by
  4.2% (!).

  The generic implementation is not really excercised on other
  architectures, outside of the trivial test_static_call_init()
  self-test"

* tag 'core-static_call-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  static_call: Fix return type of static_call_init
  tracepoint: Fix out of sync data passing by static caller
  tracepoint: Fix overly long tracepoint names
  x86/perf, static_call: Optimize x86_pmu methods
  tracepoint: Optimize using static_call()
  static_call: Allow early init
  static_call: Add some validation
  static_call: Handle tail-calls
  static_call: Add static_call_cond()
  x86/alternatives: Teach text_poke_bp() to emulate RET
  static_call: Add simple self-test for static calls
  x86/static_call: Add inline static call implementation for x86-64
  x86/static_call: Add out-of-line static call implementation
  static_call: Avoid kprobes on inline static_call()s
  static_call: Add inline static call infrastructure
  static_call: Add basic static call infrastructure
  compiler.h: Make __ADDRESSABLE() symbol truly unique
  jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved()
  module: Properly propagate MODULE_STATE_COMING failure
  module: Fix up module_notifier return values
  ...

17 files changed, 687 insertions, 148 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 9a20016d4900..b74820d8b264 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -111,6 +111,7 @@ obj-$(CONFIG_CPU_PM) += cpu_pm.o
 obj-$(CONFIG_BPF) += bpf/
 obj-$(CONFIG_KCSAN) += kcsan/
 obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
+obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call.o
 
 obj-$(CONFIG_PERF_EVENTS) += events/
 
diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
index 44a259338e33..f7e1d0eccdbc 100644
--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -15,18 +15,28 @@
 
 static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain);
 
-static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
+static int cpu_pm_notify(enum cpu_pm_event event)
 {
 	int ret;
 
 	/*
-	 * __atomic_notifier_call_chain has a RCU read critical section, which
+	 * atomic_notifier_call_chain has a RCU read critical section, which
 	 * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let
 	 * RCU know this.
 	 */
 	rcu_irq_enter_irqson();
-	ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL,
-		nr_to_call, nr_calls);
+	ret = atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL);
+	rcu_irq_exit_irqson();
+
+	return notifier_to_errno(ret);
+}
+
+static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down)
+{
+	int ret;
+
+	rcu_irq_enter_irqson();
+	ret = atomic_notifier_call_chain_robust(&cpu_pm_notifier_chain, event_up, event_down, NULL);
 	rcu_irq_exit_irqson();
 
 	return notifier_to_errno(ret);
@@ -80,18 +90,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
  */
 int cpu_pm_enter(void)
 {
-	int nr_calls = 0;
-	int ret = 0;
-
-	ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
-	if (ret)
-		/*
-		 * Inform listeners (nr_calls - 1) about failure of CPU PM
-		 * PM entry who are notified earlier to prepare for it.
-		 */
-		cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
-
-	return ret;
+	return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);
 }
 EXPORT_SYMBOL_GPL(cpu_pm_enter);
 
@@ -109,7 +108,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter);
  */
 int cpu_pm_exit(void)
 {
-	return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
+	return cpu_pm_notify(CPU_PM_EXIT);
 }
 EXPORT_SYMBOL_GPL(cpu_pm_exit);
 
@@ -131,18 +130,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit);
  */
 int cpu_cluster_pm_enter(void)
 {
-	int nr_calls = 0;
-	int ret = 0;
-
-	ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
-	if (ret)
-		/*
-		 * Inform listeners (nr_calls - 1) about failure of CPU cluster
-		 * PM entry who are notified earlier to prepare for it.
-		 */
-		cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL);
-
-	return ret;
+	return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);
 }
 EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
 
@@ -163,7 +151,7 @@ EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
  */
 int cpu_cluster_pm_exit(void)
 {
-	return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
+	return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);
 }
 EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
 
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index cdb3ffab128b..e661c61b3d6b 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -539,19 +539,25 @@ static void static_key_set_mod(struct static_key *key,
 static int __jump_label_mod_text_reserved(void *start, void *end)
 {
 	struct module *mod;
+	int ret;
 
 	preempt_disable();
 	mod = __module_text_address((unsigned long)start);
 	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+	if (!try_module_get(mod))
+		mod = NULL;
 	preempt_enable();
 
 	if (!mod)
 		return 0;
 
-
-	return __jump_label_text_reserved(mod->jump_entries,
+	ret = __jump_label_text_reserved(mod->jump_entries,
 				mod->jump_entries + mod->num_jump_entries,
 				start, end);
+
+	module_put(mod);
+
+	return ret;
 }
 
 static void __jump_label_mod_update(struct static_key *key)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e995541d277d..c16c3236f6cf 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -36,6 +36,7 @@
 #include <linux/cpu.h>
 #include <linux/jump_label.h>
 #include <linux/perf_event.h>
+#include <linux/static_call.h>
 
 #include <asm/sections.h>
 #include <asm/cacheflush.h>
@@ -1634,6 +1635,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
 	if (!kernel_text_address((unsigned long) p->addr) ||
 	    within_kprobe_blacklist((unsigned long) p->addr) ||
 	    jump_label_text_reserved(p->addr, p->addr) ||
+	    static_call_text_reserved(p->addr, p->addr) ||
 	    find_bug((unsigned long)p->addr)) {
 		ret = -EINVAL;
 		goto out;
diff --git a/kernel/module.c b/kernel/module.c
index 1c5cff34d9f2..c075a18103fb 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3275,6 +3275,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 						sizeof(unsigned long),
 						&mod->num_kprobe_blacklist);
 #endif
+#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
+	mod->static_call_sites = section_objs(info, ".static_call_sites",
+					      sizeof(*mod->static_call_sites),
+					      &mod->num_static_call_sites);
+#endif
 	mod->extable = section_objs(info, "__ex_table",
 				    sizeof(*mod->extable), &mod->num_exentries);
 
@@ -3792,9 +3797,13 @@ static int prepare_coming_module(struct module *mod)
 	if (err)
 		return err;
 
-	blocking_notifier_call_chain(&module_notify_list,
-				     MODULE_STATE_COMING, mod);
-	return 0;
+	err = blocking_notifier_call_chain_robust(&module_notify_list,
+			MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
+	err = notifier_to_errno(err);
+	if (err)
+		klp_module_going(mod);
+
+	return err;
 }
 
 static int unknown_module_param_cb(char *param, char *val, const char *modname,
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 84c987dfbe03..1b019cbca594 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -94,6 +94,34 @@ static int notifier_call_chain(struct notifier_block **nl,
 }
 NOKPROBE_SYMBOL(notifier_call_chain);
 
+/**
+ * notifier_call_chain_robust - Inform the registered notifiers about an event
+ *                              and rollback on error.
+ * @nl:		Pointer to head of the blocking notifier chain
+ * @val_up:	Value passed unmodified to the notifier function
+ * @val_down:	Value passed unmodified to the notifier function when recovering
+ *              from an error on @val_up
+ * @v		Pointer passed unmodified to the notifier function
+ *
+ * NOTE:	It is important the @nl chain doesn't change between the two
+ *		invocations of notifier_call_chain() such that we visit the
+ *		exact same notifier callbacks; this rules out any RCU usage.
+ *
+ * Returns:	the return value of the @val_up call.
+ */
+static int notifier_call_chain_robust(struct notifier_block **nl,
+				     unsigned long val_up, unsigned long val_down,
+				     void *v)
+{
+	int ret, nr = 0;
+
+	ret = notifier_call_chain(nl, val_up, v, -1, &nr);
+	if (ret & NOTIFY_STOP_MASK)
+		notifier_call_chain(nl, val_down, v, nr-1, NULL);
+
+	return ret;
+}
+
 /*
  *	Atomic notifier chain routines.  Registration and unregistration
  *	use a spinlock, and call_chain is synchronized by RCU (no locks).
@@ -144,13 +172,30 @@ int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
 
+int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v)
+{
+	unsigned long flags;
+	int ret;
+
+	/*
+	 * Musn't use RCU; because then the notifier list can
+	 * change between the up and down traversal.
+	 */
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+	spin_unlock_irqrestore(&nh->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_call_chain_robust);
+NOKPROBE_SYMBOL(atomic_notifier_call_chain_robust);
+
 /**
- *	__atomic_notifier_call_chain - Call functions in an atomic notifier chain
+ *	atomic_notifier_call_chain - Call functions in an atomic notifier chain
  *	@nh: Pointer to head of the atomic notifier chain
  *	@val: Value passed unmodified to notifier function
  *	@v: Pointer passed unmodified to notifier function
- *	@nr_to_call: See the comment for notifier_call_chain.
- *	@nr_calls: See the comment for notifier_call_chain.
  *
  *	Calls each function in a notifier chain in turn.  The functions
  *	run in an atomic context, so they must not block.
@@ -163,24 +208,16 @@ EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
  *	Otherwise the return value is the return value
  *	of the last notifier function called.
  */
-int __atomic_notifier_call_chain(struct atomic_notifier_head *nh,
-				 unsigned long val, void *v,
-				 int nr_to_call, int *nr_calls)
+int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
+			       unsigned long val, void *v)
 {
 	int ret;
 
 	rcu_read_lock();
-	ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
+	ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
 	rcu_read_unlock();
-	return ret;
-}
-EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain);
-NOKPROBE_SYMBOL(__atomic_notifier_call_chain);
 
-int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
-			       unsigned long val, void *v)
-{
-	return __atomic_notifier_call_chain(nh, val, v, -1, NULL);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
 NOKPROBE_SYMBOL(atomic_notifier_call_chain);
@@ -250,13 +287,30 @@ int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
 
+int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v)
+{
+	int ret = NOTIFY_DONE;
+
+	/*
+	 * We check the head outside the lock, but if this access is
+	 * racy then it does not matter what the result of the test
+	 * is, we re-check the list after having taken the lock anyway:
+	 */
+	if (rcu_access_pointer(nh->head)) {
+		down_read(&nh->rwsem);
+		ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+		up_read(&nh->rwsem);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_robust);
+
 /**
- *	__blocking_notifier_call_chain - Call functions in a blocking notifier chain
+ *	blocking_notifier_call_chain - Call functions in a blocking notifier chain
  *	@nh: Pointer to head of the blocking notifier chain
  *	@val: Value passed unmodified to notifier function
  *	@v: Pointer passed unmodified to notifier function
- *	@nr_to_call: See comment for notifier_call_chain.
- *	@nr_calls: See comment for notifier_call_chain.
  *
  *	Calls each function in a notifier chain in turn.  The functions
  *	run in a process context, so they are allowed to block.
@@ -268,9 +322,8 @@ EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
  *	Otherwise the return value is the return value
  *	of the last notifier function called.
  */
-int __blocking_notifier_call_chain(struct blocking_notifier_head *nh,
-				   unsigned long val, void *v,
-				   int nr_to_call, int *nr_calls)
+int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
+		unsigned long val, void *v)
 {
 	int ret = NOTIFY_DONE;
 
@@ -281,19 +334,11 @@ int __blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 	 */
 	if (rcu_access_pointer(nh->head)) {
 		down_read(&nh->rwsem);
-		ret = notifier_call_chain(&nh->head, val, v, nr_to_call,
-					nr_calls);
+		ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
 		up_read(&nh->rwsem);
 	}
 	return ret;
 }
-EXPORT_SYMBOL_GPL(__blocking_notifier_call_chain);
-
-int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
-		unsigned long val, void *v)
-{
-	return __blocking_notifier_call_chain(nh, val, v, -1, NULL);
-}
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
 /*
@@ -335,13 +380,18 @@ int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
 
+int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v)
+{
+	return notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_call_chain_robust);
+
 /**
- *	__raw_notifier_call_chain - Call functions in a raw notifier chain
+ *	raw_notifier_call_chain - Call functions in a raw notifier chain
  *	@nh: Pointer to head of the raw notifier chain
  *	@val: Value passed unmodified to notifier function
  *	@v: Pointer passed unmodified to notifier function
- *	@nr_to_call: See comment for notifier_call_chain.
- *	@nr_calls: See comment for notifier_call_chain
  *
  *	Calls each function in a notifier chain in turn.  The functions
  *	run in an undefined context.
@@ -354,18 +404,10 @@ EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
  *	Otherwise the return value is the return value
  *	of the last notifier function called.
  */
-int __raw_notifier_call_chain(struct raw_notifier_head *nh,
-			      unsigned long val, void *v,
-			      int nr_to_call, int *nr_calls)
-{
-	return notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
-}
-EXPORT_SYMBOL_GPL(__raw_notifier_call_chain);
-
 int raw_notifier_call_chain(struct raw_notifier_head *nh,
 		unsigned long val, void *v)
 {
-	return __raw_notifier_call_chain(nh, val, v, -1, NULL);
+	return notifier_call_chain(&nh->head, val, v, -1, NULL);
 }
 EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
 
@@ -437,12 +479,10 @@ int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
 EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
 
 /**
- *	__srcu_notifier_call_chain - Call functions in an SRCU notifier chain
+ *	srcu_notifier_call_chain - Call functions in an SRCU notifier chain
  *	@nh: Pointer to head of the SRCU notifier chain
  *	@val: Value passed unmodified to notifier function
  *	@v: Pointer passed unmodified to notifier function
- *	@nr_to_call: See comment for notifier_call_chain.
- *	@nr_calls: See comment for notifier_call_chain
  *
  *	Calls each function in a notifier chain in turn.  The functions
  *	run in a process context, so they are allowed to block.
@@ -454,25 +494,17 @@ EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
  *	Otherwise the return value is the return value
  *	of the last notifier function called.
  */
-int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
-			       unsigned long val, void *v,
-			       int nr_to_call, int *nr_calls)
+int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
+		unsigned long val, void *v)
 {
 	int ret;
 	int idx;
 
 	idx = srcu_read_lock(&nh->srcu);
-	ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
+	ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
 	srcu_read_unlock(&nh->srcu, idx);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(__srcu_notifier_call_chain);
-
-int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
-		unsigned long val, void *v)
-{
-	return __srcu_notifier_call_chain(nh, val, v, -1, NULL);
-}
 EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
 
 /**
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e7aa57fb2fdc..1dee70815f3c 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -706,8 +706,8 @@ static int load_image_and_restore(void)
  */
 int hibernate(void)
 {
-	int error, nr_calls = 0;
 	bool snapshot_test = false;
+	int error;
 
 	if (!hibernation_available()) {
 		pm_pr_dbg("Hibernation not available.\n");
@@ -723,11 +723,9 @@ int hibernate(void)
 
 	pr_info("hibernation entry\n");
 	pm_prepare_console();
-	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
-	if (error) {
-		nr_calls--;
-		goto Exit;
-	}
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto Restore;
 
 	ksys_sync_helper();
 
@@ -785,7 +783,8 @@ int hibernate(void)
 	/* Don't bother checking whether freezer_test_done is true */
 	freezer_test_done = false;
  Exit:
-	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+ Restore:
 	pm_restore_console();
 	hibernate_release();
  Unlock:
@@ -804,7 +803,7 @@ int hibernate(void)
  */
 int hibernate_quiet_exec(int (*func)(void *data), void *data)
 {
-	int error, nr_calls = 0;
+	int error;
 
 	lock_system_sleep();
 
@@ -815,11 +814,9 @@ int hibernate_quiet_exec(int (*func)(void *data), void *data)
 
 	pm_prepare_console();
 
-	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
-	if (error) {
-		nr_calls--;
-		goto exit;
-	}
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto restore;
 
 	error = freeze_processes();
 	if (error)
@@ -880,8 +877,9 @@ thaw:
 	thaw_processes();
 
 exit:
-	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
 
+restore:
 	pm_restore_console();
 
 	hibernate_release();
@@ -910,7 +908,7 @@ EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
  */
 static int software_resume(void)
 {
-	int error, nr_calls = 0;
+	int error;
 
 	/*
 	 * If the user said "noresume".. bail out early.
@@ -997,11 +995,9 @@ static int software_resume(void)
 
 	pr_info("resume from hibernation\n");
 	pm_prepare_console();
-	error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
-	if (error) {
-		nr_calls--;
-		goto Close_Finish;
-	}
+	error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
+	if (error)
+		goto Restore;
 
 	pm_pr_dbg("Preparing processes for hibernation restore.\n");
 	error = freeze_processes();
@@ -1017,7 +1013,8 @@ static int software_resume(void)
 	error = load_image_and_restore();
 	thaw_processes();
  Finish:
-	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
+	pm_notifier_call_chain(PM_POST_RESTORE);
+ Restore:
 	pm_restore_console();
 	pr_info("resume failed (%d)\n", error);
 	hibernate_release();
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 40f86ec4ab30..0aefd6f57e0a 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -80,18 +80,18 @@ int unregister_pm_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
 
-int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
+int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)
 {
 	int ret;
 
-	ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
-						nr_to_call, nr_calls);
+	ret = blocking_notifier_call_chain_robust(&pm_chain_head, val_up, val_down, NULL);
 
 	return notifier_to_errno(ret);
 }
+
 int pm_notifier_call_chain(unsigned long val)
 {
-	return __pm_notifier_call_chain(val, -1, NULL);
+	return blocking_notifier_call_chain(&pm_chain_head, val, NULL);
 }
 
 /* If set, devices may be suspended and resumed asynchronously. */
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 32fc89ac96c3..24f12d534515 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -210,8 +210,7 @@ static inline void suspend_test_finish(const char *label) {}
 
 #ifdef CONFIG_PM_SLEEP
 /* kernel/power/main.c */
-extern int __pm_notifier_call_chain(unsigned long val, int nr_to_call,
-				    int *nr_calls);
+extern int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down);
 extern int pm_notifier_call_chain(unsigned long val);
 #endif
 
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 8b1bb5ee7e5d..32391acc806b 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -342,18 +342,16 @@ static int suspend_test(int level)
  */
 static int suspend_prepare(suspend_state_t state)
 {
-	int error, nr_calls = 0;
+	int error;
 
 	if (!sleep_state_supported(state))
 		return -EPERM;
 
 	pm_prepare_console();
 
-	error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
-	if (error) {
-		nr_calls--;
-		goto Finish;
-	}
+	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
+	if (error)
+		goto Restore;
 
 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
 	error = suspend_freeze_processes();
@@ -363,8 +361,8 @@ static int suspend_prepare(suspend_state_t state)
 
 	suspend_stats.failed_freeze++;
 	dpm_save_failed_step(SUSPEND_FREEZE);
- Finish:
-	__pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
+	pm_notifier_call_chain(PM_POST_SUSPEND);
+ Restore:
 	pm_restore_console();
 	return error;
 }
diff --git a/kernel/power/user.c b/kernel/power/user.c
index d5eedc2baa2a..047f598f89a5 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -46,7 +46,7 @@ int is_hibernate_resume_dev(const struct inode *bd_inode)
 static int snapshot_open(struct inode *inode, struct file *filp)
 {
 	struct snapshot_data *data;
-	int error, nr_calls = 0;
+	int error;
 
 	if (!hibernation_available())
 		return -EPERM;
@@ -73,9 +73,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
 		data->mode = O_RDONLY;
 		data->free_bitmaps = false;
-		error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
-		if (error)
-			__pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL);
+		error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
 	} else {
 		/*
 		 * Resuming.  We may need to wait for the image device to
@@ -85,15 +83,11 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 
 		data->swap = -1;
 		data->mode = O_WRONLY;
-		error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
+		error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
 		if (!error) {
 			error = create_basic_memory_bitmaps();
 			data->free_bitmaps = !error;
-		} else
-			nr_calls--;
-
-		if (error)
-			__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
+		}
 	}
 	if (error)
 		hibernate_release();
diff --git a/kernel/static_call.c b/kernel/static_call.c
new file mode 100644
index 000000000000..84565c2a41b8
--- /dev/null
+++ b/kernel/static_call.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/static_call.h>
+#include <linux/bug.h>
+#include <linux/smp.h>
+#include <linux/sort.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/processor.h>
+#include <asm/sections.h>
+
+extern struct static_call_site __start_static_call_sites[],
+			       __stop_static_call_sites[];
+
+static bool static_call_initialized;
+
+/* mutex to protect key modules/sites */
+static DEFINE_MUTEX(static_call_mutex);
+
+static void static_call_lock(void)
+{
+	mutex_lock(&static_call_mutex);
+}
+
+static void static_call_unlock(void)
+{
+	mutex_unlock(&static_call_mutex);
+}
+
+static inline void *static_call_addr(struct static_call_site *site)
+{
+	return (void *)((long)site->addr + (long)&site->addr);
+}
+
+
+static inline struct static_call_key *static_call_key(const struct static_call_site *site)
+{
+	return (struct static_call_key *)
+		(((long)site->key + (long)&site->key) & ~STATIC_CALL_SITE_FLAGS);
+}
+
+/* These assume the key is word-aligned. */
+static inline bool static_call_is_init(struct static_call_site *site)
+{
+	return ((long)site->key + (long)&site->key) & STATIC_CALL_SITE_INIT;
+}
+
+static inline bool static_call_is_tail(struct static_call_site *site)
+{
+	return ((long)site->key + (long)&site->key) & STATIC_CALL_SITE_TAIL;
+}
+
+static inline void static_call_set_init(struct static_call_site *site)
+{
+	site->key = ((long)static_call_key(site) | STATIC_CALL_SITE_INIT) -
+		    (long)&site->key;
+}
+
+static int static_call_site_cmp(const void *_a, const void *_b)
+{
+	const struct static_call_site *a = _a;
+	const struct static_call_site *b = _b;
+	const struct static_call_key *key_a = static_call_key(a);
+	const struct static_call_key *key_b = static_call_key(b);
+
+	if (key_a < key_b)
+		return -1;
+
+	if (key_a > key_b)
+		return 1;
+
+	return 0;
+}
+
+static void static_call_site_swap(void *_a, void *_b, int size)
+{
+	long delta = (unsigned long)_a - (unsigned long)_b;
+	struct static_call_site *a = _a;
+	struct static_call_site *b = _b;
+	struct static_call_site tmp = *a;
+
+	a->addr = b->addr  - delta;
+	a->key  = b->key   - delta;
+
+	b->addr = tmp.addr + delta;
+	b->key  = tmp.key  + delta;
+}
+
+static inline void static_call_sort_entries(struct static_call_site *start,
+					    struct static_call_site *stop)
+{
+	sort(start, stop - start, sizeof(struct static_call_site),
+	     static_call_site_cmp, static_call_site_swap);
+}
+
+static inline bool static_call_key_has_mods(struct static_call_key *key)
+{
+	return !(key->type & 1);
+}
+
+static inline struct static_call_mod *static_call_key_next(struct static_call_key *key)
+{
+	if (!static_call_key_has_mods(key))
+		return NULL;
+
+	return key->mods;
+}
+
+static inline struct static_call_site *static_call_key_sites(struct static_call_key *key)
+{
+	if (static_call_key_has_mods(key))
+		return NULL;
+
+	return (struct static_call_site *)(key->type & ~1);
+}
+
+void __static_call_update(struct static_call_key *key, void *tramp, void *func)
+{
+	struct static_call_site *site, *stop;
+	struct static_call_mod *site_mod, first;
+
+	cpus_read_lock();
+	static_call_lock();
+
+	if (key->func == func)
+		goto done;
+
+	key->func = func;
+
+	arch_static_call_transform(NULL, tramp, func, false);
+
+	/*
+	 * If uninitialized, we'll not update the callsites, but they still
+	 * point to the trampoline and we just patched that.
+	 */
+	if (WARN_ON_ONCE(!static_call_initialized))
+		goto done;
+
+	first = (struct static_call_mod){
+		.next = static_call_key_next(key),
+		.mod = NULL,
+		.sites = static_call_key_sites(key),
+	};
+
+	for (site_mod = &first; site_mod; site_mod = site_mod->next) {
+		struct module *mod = site_mod->mod;
+
+		if (!site_mod->sites) {
+			/*
+			 * This can happen if the static call key is defined in
+			 * a module which doesn't use it.
+			 *
+			 * It also happens in the has_mods case, where the
+			 * 'first' entry has no sites associated with it.
+			 */
+			continue;
+		}
+
+		stop = __stop_static_call_sites;
+
+#ifdef CONFIG_MODULES
+		if (mod) {
+			stop = mod->static_call_sites +
+			       mod->num_static_call_sites;
+		}
+#endif
+
+		for (site = site_mod->sites;
+		     site < stop && static_call_key(site) == key; site++) {
+			void *site_addr = static_call_addr(site);
+
+			if (static_call_is_init(site)) {
+				/*
+				 * Don't write to call sites which were in
+				 * initmem and have since been freed.
+				 */
+				if (!mod && system_state >= SYSTEM_RUNNING)
+					continue;
+				if (mod && !within_module_init((unsigned long)site_addr, mod))
+					continue;
+			}
+
+			if (!kernel_text_address((unsigned long)site_addr)) {
+				WARN_ONCE(1, "can't patch static call site at %pS",
+					  site_addr);
+				continue;
+			}
+
+			arch_static_call_transform(site_addr, NULL, func,
+				static_call_is_tail(site));
+		}
+	}
+
+done:
+	static_call_unlock();
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(__static_call_update);
+
+static int __static_call_init(struct module *mod,
+			      struct static_call_site *start,
+			      struct static_call_site *stop)
+{
+	struct static_call_site *site;
+	struct static_call_key *key, *prev_key = NULL;
+	struct static_call_mod *site_mod;
+
+	if (start == stop)
+		return 0;
+
+	static_call_sort_entries(start, stop);
+
+	for (site = start; site < stop; site++) {
+		void *site_addr = static_call_addr(site);
+
+		if ((mod && within_module_init((unsigned long)site_addr, mod)) ||
+		    (!mod && init_section_contains(site_addr, 1)))
+			static_call_set_init(site);
+
+		key = static_call_key(site);
+		if (key != prev_key) {
+			prev_key = key;
+
+			/*
+			 * For vmlinux (!mod) avoid the allocation by storing
+			 * the sites pointer in the key itself. Also see
+			 * __static_call_update()'s @first.
+			 *
+			 * This allows architectures (eg. x86) to call
+			 * static_call_init() before memory allocation works.
+			 */
+			if (!mod) {
+				key->sites = site;
+				key->type |= 1;
+				goto do_transform;
+			}
+
+			site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
+			if (!site_mod)
+				return -ENOMEM;
+
+			/*
+			 * When the key has a direct sites pointer, extract
+			 * that into an explicit struct static_call_mod, so we
+			 * can have a list of modules.
+			 */
+			if (static_call_key_sites(key)) {
+				site_mod->mod = NULL;
+				site_mod->next = NULL;
+				site_mod->sites = static_call_key_sites(key);
+
+				key->mods = site_mod;
+
+				site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
+				if (!site_mod)
+					return -ENOMEM;
+			}
+
+			site_mod->mod = mod;
+			site_mod->sites = site;
+			site_mod->next = static_call_key_next(key);
+			key->mods = site_mod;
+		}
+
+do_transform:
+		arch_static_call_transform(site_addr, NULL, key->func,
+				static_call_is_tail(site));
+	}
+
+	return 0;
+}
+
+static int addr_conflict(struct static_call_site *site, void *start, void *end)
+{
+	unsigned long addr = (unsigned long)static_call_addr(site);
+
+	if (addr <= (unsigned long)end &&
+	    addr + CALL_INSN_SIZE > (unsigned long)start)
+		return 1;
+
+	return 0;
+}
+
+static int __static_call_text_reserved(struct static_call_site *iter_start,
+				       struct static_call_site *iter_stop,
+				       void *start, void *end)
+{
+	struct static_call_site *iter = iter_start;
+
+	while (iter < iter_stop) {
+		if (addr_conflict(iter, start, end))
+			return 1;
+		iter++;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_MODULES
+
+static int __static_call_mod_text_reserved(void *start, void *end)
+{
+	struct module *mod;
+	int ret;
+
+	preempt_disable();
+	mod = __module_text_address((unsigned long)start);
+	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+	if (!try_module_get(mod))
+		mod = NULL;
+	preempt_enable();
+
+	if (!mod)
+		return 0;
+
+	ret = __static_call_text_reserved(mod->static_call_sites,
+			mod->static_call_sites + mod->num_static_call_sites,
+			start, end);
+
+	module_put(mod);
+
+	return ret;
+}
+
+static int static_call_add_module(struct module *mod)
+{
+	return __static_call_init(mod, mod->static_call_sites,
+				  mod->static_call_sites + mod->num_static_call_sites);
+}
+
+static void static_call_del_module(struct module *mod)
+{
+	struct static_call_site *start = mod->static_call_sites;
+	struct static_call_site *stop = mod->static_call_sites +
+					mod->num_static_call_sites;
+	struct static_call_key *key, *prev_key = NULL;
+	struct static_call_mod *site_mod, **prev;
+	struct static_call_site *site;
+
+	for (site = start; site < stop; site++) {
+		key = static_call_key(site);
+		if (key == prev_key)
+			continue;
+
+		prev_key = key;
+
+		for (prev = &key->mods, site_mod = key->mods;
+		     site_mod && site_mod->mod != mod;
+		     prev = &site_mod->next, site_mod = site_mod->next)
+			;
+
+		if (!site_mod)
+			continue;
+
+		*prev = site_mod->next;
+		kfree(site_mod);
+	}
+}
+
+static int static_call_module_notify(struct notifier_block *nb,
+				     unsigned long val, void *data)
+{
+	struct module *mod = data;
+	int ret = 0;
+
+	cpus_read_lock();
+	static_call_lock();
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		ret = static_call_add_module(mod);
+		if (ret) {
+			WARN(1, "Failed to allocate memory for static calls");
+			static_call_del_module(mod);
+		}
+		break;
+	case MODULE_STATE_GOING:
+		static_call_del_module(mod);
+		break;
+	}
+
+	static_call_unlock();
+	cpus_read_unlock();
+
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block static_call_module_nb = {
+	.notifier_call = static_call_module_notify,
+};
+
+#else
+
+static inline int __static_call_mod_text_reserved(void *start, void *end)
+{
+	return 0;
+}
+
+#endif /* CONFIG_MODULES */
+
+int static_call_text_reserved(void *start, void *end)
+{
+	int ret = __static_call_text_reserved(__start_static_call_sites,
+			__stop_static_call_sites, start, end);
+
+	if (ret)
+		return ret;
+
+	return __static_call_mod_text_reserved(start, end);
+}
+
+int __init static_call_init(void)
+{
+	int ret;
+
+	if (static_call_initialized)
+		return 0;
+
+	cpus_read_lock();
+	static_call_lock();
+	ret = __static_call_init(NULL, __start_static_call_sites,
+				 __stop_static_call_sites);
+	static_call_unlock();
+	cpus_read_unlock();
+
+	if (ret) {
+		pr_err("Failed to allocate memory for static_call!\n");
+		BUG();
+	}
+
+	static_call_initialized = true;
+
+#ifdef CONFIG_MODULES
+	register_module_notifier(&static_call_module_nb);
+#endif
+	return 0;
+}
+early_initcall(static_call_init);
+
+#ifdef CONFIG_STATIC_CALL_SELFTEST
+
+static int func_a(int x)
+{
+	return x+1;
+}
+
+static int func_b(int x)
+{
+	return x+2;
+}
+
+DEFINE_STATIC_CALL(sc_selftest, func_a);
+
+static struct static_call_data {
+      int (*func)(int);
+      int val;
+      int expect;
+} static_call_data [] __initdata = {
+      { NULL,   2, 3 },
+      { func_b, 2, 4 },
+      { func_a, 2, 3 }
+};
+
+static int __init test_static_call_init(void)
+{
+      int i;
+
+      for (i = 0; i < ARRAY_SIZE(static_call_data); i++ ) {
+	      struct static_call_data *scd = &static_call_data[i];
+
+              if (scd->func)
+                      static_call_update(sc_selftest, scd->func);
+
+              WARN_ON(static_call(sc_selftest)(scd->val) != scd->expect);
+      }
+
+      return 0;
+}
+early_initcall(test_static_call_init);
+
+#endif /* CONFIG_STATIC_CALL_SELFTEST */
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a8d4f253ed77..2ecf7892a31b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2027,10 +2027,11 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
 {
 	struct bpf_trace_module *btm, *tmp;
 	struct module *mod = module;
+	int ret = 0;
 
 	if (mod->num_bpf_raw_events == 0 ||
 	    (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
-		return 0;
+		goto out;
 
 	mutex_lock(&bpf_module_mutex);
 
@@ -2040,6 +2041,8 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
 		if (btm) {
 			btm->module = module;
 			list_add(&btm->list, &bpf_trace_modules);
+		} else {
+			ret = -ENOMEM;
 		}
 		break;
 	case MODULE_STATE_GOING:
@@ -2055,7 +2058,8 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
 
 	mutex_unlock(&bpf_module_mutex);
 
-	return 0;
+out:
+	return notifier_from_errno(ret);
 }
 
 static struct notifier_block bpf_module_nb = {
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d3e5de717df2..25b72a73608a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9074,7 +9074,7 @@ static int trace_module_notify(struct notifier_block *self,
 		break;
 	}
 
-	return 0;
+	return NOTIFY_OK;
 }
 
 static struct notifier_block trace_module_nb = {
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a85effb2373b..beebf2cd364b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2646,7 +2646,7 @@ static int trace_module_notify(struct notifier_block *self,
 	mutex_unlock(&trace_types_lock);
 	mutex_unlock(&event_mutex);
 
-	return 0;
+	return NOTIFY_OK;
 }
 
 static struct notifier_block trace_module_nb = {
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index d4e31e969206..bb7783b90361 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -96,7 +96,7 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self,
 		if (val == MODULE_STATE_COMING)
 			hold_module_trace_bprintk_format(start, end);
 	}
-	return 0;
+	return NOTIFY_OK;
 }
 
 /*
@@ -174,7 +174,7 @@ __init static int
 module_trace_bprintk_format_notify(struct notifier_block *self,
 		unsigned long val, void *data)
 {
-	return 0;
+	return NOTIFY_OK;
 }
 static inline const char **
 find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 73956eaff8a9..26efd22f0633 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -221,6 +221,29 @@ static void *func_remove(struct tracepoint_func **funcs,
 	return old;
 }
 
+static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func *tp_funcs, bool sync)
+{
+	void *func = tp->iterator;
+
+	/* Synthetic events do not have static call sites */
+	if (!tp->static_call_key)
+		return;
+
+	if (!tp_funcs[1].func) {
+		func = tp_funcs[0].func;
+		/*
+		 * If going from the iterator back to a single caller,
+		 * we need to synchronize with __DO_TRACE to make sure
+		 * that the data passed to the callback is the one that
+		 * belongs to that callback.
+		 */
+		if (sync)
+			tracepoint_synchronize_unregister();
+	}
+
+	__static_call_update(tp->static_call_key, tp->static_call_tramp, func);
+}
+
 /*
  * Add the probe function to a tracepoint.
  */
@@ -251,8 +274,9 @@ static int tracepoint_add_func(struct tracepoint *tp,
 	 * include/linux/tracepoint.h using rcu_dereference_sched().
 	 */
 	rcu_assign_pointer(tp->funcs, tp_funcs);
-	if (!static_key_enabled(&tp->key))
-		static_key_slow_inc(&tp->key);
+	tracepoint_update_call(tp, tp_funcs, false);
+	static_key_enable(&tp->key);
+
 	release_probes(old);
 	return 0;
 }
@@ -281,10 +305,13 @@ static int tracepoint_remove_func(struct tracepoint *tp,
 		if (tp->unregfunc && static_key_enabled(&tp->key))
 			tp->unregfunc();
 
-		if (static_key_enabled(&tp->key))
-			static_key_slow_dec(&tp->key);
+		static_key_disable(&tp->key);
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+	} else {
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+		tracepoint_update_call(tp, tp_funcs,
+				       tp_funcs[0].func != old[0].func);
 	}
-	rcu_assign_pointer(tp->funcs, tp_funcs);
 	release_probes(old);
 	return 0;
 }
@@ -521,7 +548,7 @@ static int tracepoint_module_notify(struct notifier_block *self,
 	case MODULE_STATE_UNFORMED:
 		break;
 	}
-	return ret;
+	return notifier_from_errno(ret);
 }
 
 static struct notifier_block tracepoint_module_nb = {