#include <linux/module.h>
#include <litmus/ftdev.h>
#include <litmus/litmus.h>
#include <litmus/trace.h>
/******************************************************************************/
/* Allocation */
/******************************************************************************/
static struct ftdev overhead_dev;
#define trace_ts_buf overhead_dev.minor[0].buf
static unsigned int ts_seq_no = 0;
static inline void __save_timestamp_cpu(unsigned long event,
uint8_t type, uint8_t cpu)
{
unsigned int seq_no;
struct timestamp *ts;
seq_no = fetch_and_inc((int *) &ts_seq_no);
if (ft_buffer_start_write(trace_ts_buf, (void**) &ts)) {
ts->event = event;
ts->timestamp = ft_timestamp();
ts->seq_no = seq_no;
ts->cpu = cpu;
ts->task_type = type;
ft_buffer_finish_write(trace_ts_buf, ts);
}
}
static inline void __save_timestamp(unsigned long event,
uint8_t type)
{
__save_timestamp_cpu(event, type, raw_smp_processor_id());
}
feather_callback void save_timestamp(unsigned long event)
{
__save_timestamp(event, TSK_UNKNOWN);
}
feather_callback void save_timestamp_def(unsigned long event,
unsigned long type)
{
__save_timestamp(event, (uint8_t) type);
}
feather_callback void save_timestamp_task(unsigned long event,
unsigned long t_ptr)
{
int rt = is_realtime((struct task_struct *) t_ptr);
__save_timestamp(event, rt ? TSK_RT : TSK_BE);
}
feather_callback void save_timestamp_cpu(unsigned long event,
unsigned long cpu)
{
__save_timestamp_cpu(event, TSK_UNKNOWN, cpu);
}
/******************************************************************************/
/* DEVICE FILE DRIVER */
/******************************************************************************/
/*
* should be 8M; it is the max we can ask to buddy system allocator (MAX_ORDER)
* and we might not get as much
*/
#define NO_TIMESTAMPS (2 << 11)
/* set MAJOR to 0 to have it dynamically assigned */
#define FT_TRACE_MAJOR 252
static int alloc_timestamp_buffer(struct ftdev* ftdev, unsigned int idx)
{
unsigned int count = NO_TIMESTAMPS;
while (count && !trace_ts_buf) {
printk("time stamp buffer: trying to allocate %u time stamps.\n", count);
ftdev->minor[idx].buf = alloc_ft_buffer(count, sizeof(struct timestamp));
count /= 2;
}
return ftdev->minor[idx].buf ? 0 : -ENOMEM;
}
static void free_timestamp_buffer(struct ftdev* ftdev, unsigned int idx)
{
free_ft_buffer(ftdev->minor[idx].buf);
ftdev->minor[idx].buf = NULL;
}
static int __init init_ft_overhead_trace(void)
{
printk("Initializing Feather-Trace overhead tracing device.\n");
ftdev_init(&overhead_dev, THIS_MODULE);
overhead_dev.minor_cnt = 1; /* only one buffer */
overhead_dev.alloc = alloc_timestamp_buffer;
overhead_dev.free = free_timestamp_buffer;
return register_ftdev(&overhead_dev, "ft_trace", FT_TRACE_MAJOR);
}
module_init(init_ft_overhead_trace);
