Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2)  * @file event_buffer.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * @remark Copyright 2002 OProfile authors
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * @remark Read the file COPYING
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * @author John Levon <levon@movementarian.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  * This is the global event buffer that the user-space
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  * daemon reads from. The event buffer is an untyped array
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * of unsigned longs. Entries are prefixed by the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * escape value ESCAPE_CODE followed by an identifying code.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/vmalloc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/oprofile.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/sched/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/capability.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/dcookies.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include "oprof.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include "event_buffer.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include "oprofile_stats.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) DEFINE_MUTEX(buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) static unsigned long buffer_opened;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) static DECLARE_WAIT_QUEUE_HEAD(buffer_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) static unsigned long *event_buffer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) static unsigned long buffer_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static unsigned long buffer_watershed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) static size_t buffer_pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) /* atomic_t because wait_event checks it outside of buffer_mutex */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) static atomic_t buffer_ready = ATOMIC_INIT(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  * Add an entry to the event buffer. When we get near to the end we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  * wake up the process sleeping on the read() of the file. To protect
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  * the event_buffer this function may only be called when buffer_mutex
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * is set.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) void add_event_entry(unsigned long value)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	 * This shouldn't happen since all workqueues or handlers are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	 * canceled or flushed before the event buffer is freed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	if (!event_buffer) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		WARN_ON_ONCE(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	if (buffer_pos == buffer_size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		atomic_inc(&oprofile_stats.event_lost_overflow);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	event_buffer[buffer_pos] = value;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	if (++buffer_pos == buffer_size - buffer_watershed) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 		atomic_set(&buffer_ready, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 		wake_up(&buffer_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) /* Wake up the waiting process if any. This happens
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69)  * on "echo 0 >/dev/oprofile/enable" so the daemon
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70)  * processes the data remaining in the event buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) void wake_up_buffer_waiter(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	mutex_lock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	atomic_set(&buffer_ready, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	wake_up(&buffer_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	mutex_unlock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) int alloc_event_buffer(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	raw_spin_lock_irqsave(&oprofilefs_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	buffer_size = oprofile_buffer_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	buffer_watershed = oprofile_buffer_watershed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	raw_spin_unlock_irqrestore(&oprofilefs_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	if (buffer_watershed >= buffer_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	buffer_pos = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	event_buffer = vmalloc(array_size(buffer_size, sizeof(unsigned long)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	if (!event_buffer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) void free_event_buffer(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	mutex_lock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	vfree(event_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	buffer_pos = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	event_buffer = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	mutex_unlock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) static int event_buffer_open(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	int err = -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	if (!perfmon_capable())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	if (test_and_set_bit_lock(0, &buffer_opened))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	/* Register as a user of dcookies
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	 * to ensure they persist for the lifetime of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	 * the open event file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	file->private_data = dcookie_register();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	if (!file->private_data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	if ((err = oprofile_setup()))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	/* NB: the actual start happens from userspace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	 * echo 1 >/dev/oprofile/enable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	return nonseekable_open(inode, file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) fail:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	dcookie_unregister(file->private_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	__clear_bit_unlock(0, &buffer_opened);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) static int event_buffer_release(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	oprofile_stop();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	oprofile_shutdown();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	dcookie_unregister(file->private_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	buffer_pos = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	atomic_set(&buffer_ready, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	__clear_bit_unlock(0, &buffer_opened);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) static ssize_t event_buffer_read(struct file *file, char __user *buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 				 size_t count, loff_t *offset)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	int retval = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	size_t const max = buffer_size * sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	/* handling partial reads is more trouble than it's worth */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	if (count != max || *offset)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	wait_event_interruptible(buffer_wait, atomic_read(&buffer_ready));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	if (signal_pending(current))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 		return -EINTR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	/* can't currently happen */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	if (!atomic_read(&buffer_ready))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	mutex_lock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	/* May happen if the buffer is freed during pending reads. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	if (!event_buffer) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		retval = -EINTR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	atomic_set(&buffer_ready, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	retval = -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	count = buffer_pos * sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	if (copy_to_user(buf, event_buffer, count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	retval = count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	buffer_pos = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	mutex_unlock(&buffer_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) const struct file_operations event_buffer_fops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	.open		= event_buffer_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	.release	= event_buffer_release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	.read		= event_buffer_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	.llseek		= no_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) };