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/**
* Copyright (C) ARM Limited 2010-2013. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/current.h>
#include <linux/spinlock.h>
static DEFINE_SPINLOCK(annotate_lock);
static bool collect_annotations = false;
static int annotate_copy(struct file *file, char const __user *buf, size_t count)
{
int cpu = 0;
int write = per_cpu(gator_buffer_write, cpu)[ANNOTATE_BUF];
if (file == NULL) {
// copy from kernel
memcpy(&per_cpu(gator_buffer, cpu)[ANNOTATE_BUF][write], buf, count);
} else {
// copy from user space
if (copy_from_user(&per_cpu(gator_buffer, cpu)[ANNOTATE_BUF][write], buf, count) != 0)
return -1;
}
per_cpu(gator_buffer_write, cpu)[ANNOTATE_BUF] = (write + count) & gator_buffer_mask[ANNOTATE_BUF];
return 0;
}
static ssize_t annotate_write(struct file *file, char const __user *buf, size_t count_orig, loff_t *offset)
{
int pid, cpu, header_size, available, contiguous, length1, length2, size, count = count_orig & 0x7fffffff;
if (*offset) {
return -EINVAL;
}
// Annotations are not supported in interrupt context
if (in_interrupt()) {
printk(KERN_WARNING "gator: Annotations are not supported in interrupt context\n");
return -EINVAL;
}
retry:
// synchronize between cores and with collect_annotations
spin_lock(&annotate_lock);
if (!collect_annotations) {
// Not collecting annotations, tell the caller everything was written
size = count_orig;
goto annotate_write_out;
}
// Annotation only uses a single per-cpu buffer as the data must be in order to the engine
cpu = 0;
if (current == NULL) {
pid = 0;
} else {
pid = current->pid;
}
// determine total size of the payload
header_size = MAXSIZE_PACK32 * 3 + MAXSIZE_PACK64;
available = buffer_bytes_available(cpu, ANNOTATE_BUF) - header_size;
size = count < available ? count : available;
if (size <= 0) {
// Buffer is full, wait until space is available
spin_unlock(&annotate_lock);
wait_event_interruptible(gator_annotate_wait, buffer_bytes_available(cpu, ANNOTATE_BUF) > header_size || !collect_annotations);
goto retry;
}
// synchronize shared variables annotateBuf and annotatePos
if (per_cpu(gator_buffer, cpu)[ANNOTATE_BUF]) {
u64 time = gator_get_time();
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, get_physical_cpu());
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, pid);
gator_buffer_write_packed_int64(cpu, ANNOTATE_BUF, time);
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, size);
// determine the sizes to capture, length1 + length2 will equal size
contiguous = contiguous_space_available(cpu, ANNOTATE_BUF);
if (size < contiguous) {
length1 = size;
length2 = 0;
} else {
length1 = contiguous;
length2 = size - contiguous;
}
if (annotate_copy(file, buf, length1) != 0) {
size = -EINVAL;
goto annotate_write_out;
}
if (length2 > 0 && annotate_copy(file, &buf[length1], length2) != 0) {
size = -EINVAL;
goto annotate_write_out;
}
// Check and commit; commit is set to occur once buffer is 3/4 full
buffer_check(cpu, ANNOTATE_BUF, time);
}
annotate_write_out:
spin_unlock(&annotate_lock);
// return the number of bytes written
return size;
}
#include "gator_annotate_kernel.c"
static int annotate_release(struct inode *inode, struct file *file)
{
int cpu = 0;
// synchronize between cores
spin_lock(&annotate_lock);
if (per_cpu(gator_buffer, cpu)[ANNOTATE_BUF] && buffer_check_space(cpu, ANNOTATE_BUF, MAXSIZE_PACK64 + 3 * MAXSIZE_PACK32)) {
uint32_t pid = current->pid;
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, get_physical_cpu());
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, pid);
gator_buffer_write_packed_int64(cpu, ANNOTATE_BUF, 0); // time
gator_buffer_write_packed_int(cpu, ANNOTATE_BUF, 0); // size
}
// Check and commit; commit is set to occur once buffer is 3/4 full
buffer_check(cpu, ANNOTATE_BUF, gator_get_time());
spin_unlock(&annotate_lock);
return 0;
}
static const struct file_operations annotate_fops = {
.write = annotate_write,
.release = annotate_release
};
static int gator_annotate_create_files(struct super_block *sb, struct dentry *root)
{
return gatorfs_create_file_perm(sb, root, "annotate", &annotate_fops, 0666);
}
static int gator_annotate_start(void)
{
collect_annotations = true;
return 0;
}
static void gator_annotate_stop(void)
{
// the spinlock here will ensure that when this function exits, we are not in the middle of an annotation
spin_lock(&annotate_lock);
collect_annotations = false;
wake_up(&gator_annotate_wait);
spin_unlock(&annotate_lock);
}
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