#include "llc.h"

#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <asm/unistd.h>
#include <time.h>
#include <linux/kernel.h>

long perf_event_open(struct perf_event_attr* hw_event,
                            pid_t pid,
                            int cpu,
                            int group_fd,
                            unsigned long flags) {
  return (syscall(__NR_perf_event_open, hw_event, pid, cpu, group_fd, flags));
}

void config_event(struct perf_event_attr* pe) {
  pe->type = PERF_TYPE_HW_CACHE;
  pe->size = sizeof(struct perf_event_attr);
  pe->config = PERF_COUNT_HW_CACHE_LL                  |
               PERF_COUNT_HW_CACHE_OP_READ      <<  8  |
               PERF_COUNT_HW_CACHE_RESULT_MISS  << 16;
  pe->disabled        = 1;
  pe->exclude_kernel  = 1;
  pe->exclude_hv      = 1;
}

int init_event(struct perf_event_attr* pe) {
  int fd = perf_event_open(pe, ALL_PIDS, CPU_0, LEADER, NO_FLAGS);
  if (fd == -1) {
    printk(KERN_INFO "Error with the LLC counter: %d", pe->config);
    exit(EXIT_FAILURE);
  }
  return fd;
}

void activate_event(int fd) {
  ioctl(fd, PERF_EVENT_IOC_RESET, 0);
  ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);
}

void close_event(int fd) {
  ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
  close(fd);
}

int setup_BE_monitor() {
  struct perf_event_attr pe_BE_monitor;
  memset(&pe_BE_monitor, 0, sizeof(struct perf_event_attr));
  config_event(&pe_BE_monitor);
  int fd = init_event(&pe_BE_monitor);
  activate_event(fd);
  return fd;
}

long long query_BE_monitor(int fd) {
  long long count = 0;
  read(fd, &count, sizeof(count));
  return count;
}

bool do_block_BE(int fd, long long max_misses) {
  return (query_BE_monitor(fd) > max_misses);
}

void close_BE_monitor(int fd) { close_event(fd); }