From d3a225b7a8c1c5132f48fe3c04a99317c8da23ad Mon Sep 17 00:00:00 2001
From: Connor O'Brien <connoro@google.com>
Date: Mon, 22 Jan 2018 18:28:08 -0800
Subject: [PATCH] ANDROID: cpufreq: Add time_in_state to /proc/uid directories

Add per-uid files that report the data in binary format rather than
text, to allow faster reading & parsing by userspace.

Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 72339335
Test: compare values to those reported in /proc/uid_time_in_state
Change-Id: I463039ea7f17b842be4c70024fe772539fe2ce02
---
 drivers/cpufreq/cpufreq_times.c | 49 +++++++++++++++++++++++++++++++++
 fs/proc/uid.c                   | 16 ++++++++++-
 include/linux/cpufreq_times.h   |  1 +
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq_times.c b/drivers/cpufreq/cpufreq_times.c
index 5e19ac5c8157..f560e10ba183 100644
--- a/drivers/cpufreq/cpufreq_times.c
+++ b/drivers/cpufreq/cpufreq_times.c
@@ -58,6 +58,19 @@ static struct cpu_freqs *all_freqs[NR_CPUS];
 
 static unsigned int next_offset;
 
+
+/* Caller must hold rcu_read_lock() */
+static struct uid_entry *find_uid_entry_rcu(uid_t uid)
+{
+	struct uid_entry *uid_entry;
+
+	hash_for_each_possible_rcu(uid_hash_table, uid_entry, hash, uid) {
+		if (uid_entry->uid == uid)
+			return uid_entry;
+	}
+	return NULL;
+}
+
 /* Caller must hold uid lock */
 static struct uid_entry *find_uid_entry_locked(uid_t uid)
 {
@@ -127,6 +140,36 @@ static bool freq_index_invalid(unsigned int index)
 	return true;
 }
 
+static int single_uid_time_in_state_show(struct seq_file *m, void *ptr)
+{
+	struct uid_entry *uid_entry;
+	unsigned int i;
+	u64 time;
+	uid_t uid = from_kuid_munged(current_user_ns(), *(kuid_t *)m->private);
+
+	if (uid == overflowuid)
+		return -EINVAL;
+
+	rcu_read_lock();
+
+	uid_entry = find_uid_entry_rcu(uid);
+	if (!uid_entry) {
+		rcu_read_unlock();
+		return 0;
+	}
+
+	for (i = 0; i < uid_entry->max_state; ++i) {
+		if (freq_index_invalid(i))
+			continue;
+		time = nsec_to_clock_t(uid_entry->time_in_state[i]);
+		seq_write(m, &time, sizeof(time));
+	}
+
+	rcu_read_unlock();
+
+	return 0;
+}
+
 static void *uid_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	if (*pos >= HASH_SIZE(uid_hash_table))
@@ -394,6 +437,12 @@ static int uid_time_in_state_open(struct inode *inode, struct file *file)
 	return seq_open(file, &uid_time_in_state_seq_ops);
 }
 
+int single_uid_time_in_state_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, single_uid_time_in_state_show,
+			&(inode->i_uid));
+}
+
 static const struct file_operations uid_time_in_state_fops = {
 	.open		= uid_time_in_state_open,
 	.read		= seq_read,
diff --git a/fs/proc/uid.c b/fs/proc/uid.c
index ec4e2ae4f6f7..9e15be510d71 100644
--- a/fs/proc/uid.c
+++ b/fs/proc/uid.c
@@ -2,6 +2,7 @@
  * /proc/uid support
  */
 
+#include <linux/cpufreq_times.h>
 #include <linux/fs.h>
 #include <linux/hashtable.h>
 #include <linux/init.h>
@@ -82,7 +83,20 @@ struct uid_entry {
 	.fop	= FOP,					\
 }
 
-static const struct uid_entry uid_base_stuff[] = {};
+#ifdef CONFIG_CPU_FREQ_TIMES
+static const struct file_operations proc_uid_time_in_state_operations = {
+	.open		= single_uid_time_in_state_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+#endif
+
+static const struct uid_entry uid_base_stuff[] = {
+#ifdef CONFIG_CPU_FREQ_TIMES
+	NOD("time_in_state", 0444, NULL, &proc_uid_time_in_state_operations),
+#endif
+};
 
 static const struct inode_operations proc_uid_def_inode_operations = {
 	.setattr	= proc_setattr,
diff --git a/include/linux/cpufreq_times.h b/include/linux/cpufreq_times.h
index b7ea7d343317..e84b576a20d5 100644
--- a/include/linux/cpufreq_times.h
+++ b/include/linux/cpufreq_times.h
@@ -28,6 +28,7 @@ void cpufreq_acct_update_power(struct task_struct *p, u64 cputime);
 void cpufreq_times_create_policy(struct cpufreq_policy *policy);
 void cpufreq_times_record_transition(struct cpufreq_freqs *freq);
 void cpufreq_task_times_remove_uids(uid_t uid_start, uid_t uid_end);
+int single_uid_time_in_state_open(struct inode *inode, struct file *file);
 #else
 static inline void cpufreq_times_create_policy(struct cpufreq_policy *policy) {}
 static inline void cpufreq_times_record_transition(