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/**
* Copyright (C) ARM Limited 2010-2011. 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>
#define ANNOTATE_SIZE (16*1024)
static DEFINE_SPINLOCK(annotate_lock);
static char *annotateBuf;
static char *annotateBuf0;
static char *annotateBuf1;
static int annotatePos;
static int annotateSel;
static bool collect_annotations = false;
static ssize_t annotate_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
char tempBuffer[512];
int remaining, size;
uint32_t tid;
if (*offset)
return -EINVAL;
// determine size to capture
size = count < sizeof(tempBuffer) ? count : sizeof(tempBuffer);
// note: copy may be for naught if remaining is zero, but better to do the copy outside of the spinlock
if (file == NULL) {
// copy from kernel
memcpy(tempBuffer, buf, size);
// set the thread id to the kernel thread, not the current thread
tid = -1;
} else {
// copy from user space
if (copy_from_user(tempBuffer, buf, size) != 0)
return -EINVAL;
tid = current->pid;
}
// synchronize shared variables annotateBuf and annotatePos
spin_lock(&annotate_lock);
if (collect_annotations && annotateBuf) {
remaining = ANNOTATE_SIZE - annotatePos - 256; // pad for headers and release
size = size < remaining ? size : remaining;
if (size > 0) {
uint64_t time = gator_get_time();
uint32_t cpuid = smp_processor_id();
int pos = annotatePos;
pos += gator_write_packed_int(&annotateBuf[pos], tid);
pos += gator_write_packed_int64(&annotateBuf[pos], time);
pos += gator_write_packed_int(&annotateBuf[pos], cpuid);
pos += gator_write_packed_int(&annotateBuf[pos], size);
memcpy(&annotateBuf[pos], tempBuffer, size);
annotatePos = pos + size;
}
}
spin_unlock(&annotate_lock);
if (size <= 0) {
wake_up(&gator_buffer_wait);
return 0;
}
// return the number of bytes written
return size;
}
#include "gator_annotate_kernel.c"
static int annotate_release(struct inode *inode, struct file *file)
{
int remaining = ANNOTATE_SIZE - annotatePos;
if (remaining < 16) {
return -EFAULT;
}
spin_lock(&annotate_lock);
if (annotateBuf) {
uint32_t tid = current->pid;
int pos = annotatePos;
pos += gator_write_packed_int(&annotateBuf[pos], tid);
pos += gator_write_packed_int64(&annotateBuf[pos], 0); // time
pos += gator_write_packed_int(&annotateBuf[pos], 0); // cpuid
pos += gator_write_packed_int(&annotateBuf[pos], 0); // size
annotatePos = pos;
}
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)
{
annotateBuf = NULL;
return gatorfs_create_file_perm(sb, root, "annotate", &annotate_fops, 0666);
}
static int gator_annotate_init(void)
{
annotateBuf0 = kmalloc(ANNOTATE_SIZE, GFP_KERNEL);
annotateBuf1 = kmalloc(ANNOTATE_SIZE, GFP_KERNEL);
if (!annotateBuf0 || !annotateBuf1)
return -1;
return 0;
}
static int gator_annotate_start(void)
{
annotateSel = 0;
annotatePos = 1;
annotateBuf = annotateBuf0;
annotateBuf[0] = FRAME_ANNOTATE;
collect_annotations = true;
return 0;
}
static void gator_annotate_stop(void)
{
collect_annotations = false;
}
static void gator_annotate_shutdown(void)
{
spin_lock(&annotate_lock);
annotateBuf = NULL;
spin_unlock(&annotate_lock);
}
static void gator_annotate_exit(void)
{
spin_lock(&annotate_lock);
kfree(annotateBuf0);
kfree(annotateBuf1);
annotateBuf = annotateBuf0 = annotateBuf1 = NULL;
spin_unlock(&annotate_lock);
}
static int gator_annotate_ready(void)
{
return annotatePos > 1 && annotateBuf;
}
static int gator_annotate_read(char **buffer)
{
int len;
if (!gator_annotate_ready())
return 0;
annotateSel = !annotateSel;
if (buffer)
*buffer = annotateBuf;
spin_lock(&annotate_lock);
len = annotatePos;
annotateBuf = annotateSel ? annotateBuf1 : annotateBuf0;
annotateBuf[0] = FRAME_ANNOTATE;
annotatePos = 1;
spin_unlock(&annotate_lock);
return len;
}
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