From 3936c80525bbc80ad40546a24ffe0d9604e57ca1 Mon Sep 17 00:00:00 2001
From: Neill Kapron <nkapron@google.com>
Date: Thu, 9 Mar 2023 16:51:37 +0000
Subject: [PATCH] Revert "exit: Remove profile_task_exit & profile_munmap"

This reverts commit 2d4bcf886e42f0f4846a3d9bdc3a90d278903a2e, which
removed hooks required for Android uid_sys_stats.c.

Bug: 219790626
Bug: 315178116
[nkapron: resolve conflict with 2873cd31a20c exit: Remove profile_handoff_task]
Signed-off-by: Neill Kapron <nkapron@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:bd772a54d267d0c67b9350fb5a0273d1b8f237fd)
(cherry picked from https://android-review.googlesource.com/q/commit:ac4bfe2bb0eeb3840e29a8bd4ee88aa04a15a7ca)
Merged-In: Icea00bbf9abe2fb17312b25f2d575d29aa360999
Change-Id: Icea00bbf9abe2fb17312b25f2d575d29aa360999
---
 include/linux/profile.h | 26 ++++++++++++++++++++
 kernel/exit.c           |  1 +
 kernel/profile.c        | 53 +++++++++++++++++++++++++++++++++++++++++
 mm/mmap.c               |  1 +
 4 files changed, 81 insertions(+)

diff --git a/include/linux/profile.h b/include/linux/profile.h
index 11db1ec516e2..75258860a5e1 100644
--- a/include/linux/profile.h
+++ b/include/linux/profile.h
@@ -31,6 +31,11 @@ static inline int create_proc_profile(void)
 }
 #endif
 
+enum profile_type {
+	PROFILE_TASK_EXIT,
+	PROFILE_MUNMAP
+};
+
 #ifdef CONFIG_PROFILING
 
 extern int prof_on __read_mostly;
@@ -61,6 +66,15 @@ static inline void profile_hit(int type, void *ip)
 struct task_struct;
 struct mm_struct;
 
+/* task is in do_exit() */
+void profile_task_exit(struct task_struct * task);
+
+/* sys_munmap */
+void profile_munmap(unsigned long addr);
+
+int profile_event_register(enum profile_type, struct notifier_block * n);
+int profile_event_unregister(enum profile_type, struct notifier_block * n);
+
 #else
 
 #define prof_on 0
@@ -85,6 +99,18 @@ static inline void profile_hit(int type, void *ip)
 	return;
 }
 
+static inline int profile_event_register(enum profile_type t, struct notifier_block * n)
+{
+	return -ENOSYS;
+}
+
+static inline int profile_event_unregister(enum profile_type t, struct notifier_block * n)
+{
+	return -ENOSYS;
+}
+
+#define profile_task_exit(a) do { } while (0)
+#define profile_munmap(a) do { } while (0)
 
 #endif /* CONFIG_PROFILING */
 
diff --git a/kernel/exit.c b/kernel/exit.c
index aedc0832c9f4..4beb5ce0d124 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -817,6 +817,7 @@ void __noreturn do_exit(long code)
 
 	WARN_ON(tsk->plug);
 
+	profile_task_exit(tsk);
 	kcov_task_exit(tsk);
 	kmsan_task_exit(tsk);
 
diff --git a/kernel/profile.c b/kernel/profile.c
index 8a77769bc4b4..f568049eb1fe 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -136,6 +136,59 @@ int __ref profile_init(void)
 	return -ENOMEM;
 }
 
+/* Profile event notifications */
+
+static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
+static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
+
+void profile_task_exit(struct task_struct *task)
+{
+	blocking_notifier_call_chain(&task_exit_notifier, 0, task);
+}
+
+void profile_munmap(unsigned long addr)
+{
+	blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
+}
+
+int profile_event_register(enum profile_type type, struct notifier_block *n)
+{
+	int err = -EINVAL;
+
+	switch (type) {
+	case PROFILE_TASK_EXIT:
+		err = blocking_notifier_chain_register(
+				&task_exit_notifier, n);
+		break;
+	case PROFILE_MUNMAP:
+		err = blocking_notifier_chain_register(
+				&munmap_notifier, n);
+		break;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(profile_event_register);
+
+int profile_event_unregister(enum profile_type type, struct notifier_block *n)
+{
+	int err = -EINVAL;
+
+	switch (type) {
+	case PROFILE_TASK_EXIT:
+		err = blocking_notifier_chain_unregister(
+				&task_exit_notifier, n);
+		break;
+	case PROFILE_MUNMAP:
+		err = blocking_notifier_chain_unregister(
+				&munmap_notifier, n);
+		break;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(profile_event_unregister);
+
 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
 /*
  * Each cpu has a pair of open-addressed hashtables for pending
diff --git a/mm/mmap.c b/mm/mmap.c
index 9fa8bc3f5d47..1d43f310ffdd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3030,6 +3030,7 @@ EXPORT_SYMBOL(vm_munmap);
 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
 {
 	addr = untagged_addr(addr);
+	profile_munmap(addr);
 	return __vm_munmap(addr, len, true);
 }