// SPDX-License-Identifier: GPL-2.0

#include <stdint.h>
#include "resctrl.h"

struct read_format {
        __u64 nr;                       /* The number of events */
        struct {
                __u64 value;            /* The value of the event */
        } values[2];
};

static struct perf_event_attr pea_llc_miss;
static struct read_format rf_cqm;
static int fd_lm;
char llc_occup_path[1024];

static void initialize_perf_event_attr(void)
{
        pea_llc_miss.type = PERF_TYPE_HARDWARE;
        pea_llc_miss.size = sizeof(struct perf_event_attr);
        pea_llc_miss.read_format = PERF_FORMAT_GROUP;
        pea_llc_miss.exclude_kernel = 1;
        pea_llc_miss.exclude_hv = 1;
        pea_llc_miss.exclude_idle = 1;
        pea_llc_miss.exclude_callchain_kernel = 1;
        pea_llc_miss.inherit = 1;
        pea_llc_miss.exclude_guest = 1;
        pea_llc_miss.disabled = 1;
}

static void ioctl_perf_event_ioc_reset_enable(void)
{
        ioctl(fd_lm, PERF_EVENT_IOC_RESET, 0);
        ioctl(fd_lm, PERF_EVENT_IOC_ENABLE, 0);
}

static int perf_event_open_llc_miss(pid_t pid, int cpu_no)
{
        fd_lm = perf_event_open(&pea_llc_miss, pid, cpu_no, -1,
                                PERF_FLAG_FD_CLOEXEC);
        if (fd_lm == -1) {
                perror("Error opening leader");
                ctrlc_handler(0, NULL, NULL);
                return -1;
        }

        return 0;
}

static int initialize_llc_perf(void)
{
        memset(&pea_llc_miss, 0, sizeof(struct perf_event_attr));
        memset(&rf_cqm, 0, sizeof(struct read_format));

        /* Initialize perf_event_attr structures for HW_CACHE_MISSES */
        initialize_perf_event_attr();

        pea_llc_miss.config = PERF_COUNT_HW_CACHE_MISSES;

        rf_cqm.nr = 1;

        return 0;
}

static int reset_enable_llc_perf(pid_t pid, int cpu_no)
{
        int ret = 0;

        ret = perf_event_open_llc_miss(pid, cpu_no);
        if (ret < 0)
                return ret;

        /* Start counters to log values */
        ioctl_perf_event_ioc_reset_enable();

        return 0;
}

/*
 * get_llc_perf:        llc cache miss through perf events
 * @cpu_no:             CPU number that the benchmark PID is binded to
 *
 * Perf events like HW_CACHE_MISSES could be used to validate number of
 * cache lines allocated.
 *
 * Return: =0 on success.  <0 on failure.
 */
static int get_llc_perf(unsigned long *llc_perf_miss)
{
        __u64 total_misses;

        /* Stop counters after one span to get miss rate */

        ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0);

        if (read(fd_lm, &rf_cqm, sizeof(struct read_format)) == -1) {
                perror("Could not get llc misses through perf");

                return -1;
        }

        total_misses = rf_cqm.values[0].value;

        close(fd_lm);

        *llc_perf_miss = total_misses;

        return 0;
}

/*
 * Get LLC Occupancy as reported by RESCTRL FS
 * For CQM,
 * 1. If con_mon grp and mon grp given, then read from mon grp in
 * con_mon grp
 * 2. If only con_mon grp given, then read from con_mon grp
 * 3. If both not given, then read from root con_mon grp
 * For CAT,
 * 1. If con_mon grp given, then read from it
 * 2. If con_mon grp not given, then read from root con_mon grp
 *
 * Return: =0 on success.  <0 on failure.
 */
static int get_llc_occu_resctrl(unsigned long *llc_occupancy)
{
        FILE *fp;

        fp = fopen(llc_occup_path, "r");
        if (!fp) {
                perror("Failed to open results file");

                return errno;
        }
        if (fscanf(fp, "%lu", llc_occupancy) <= 0) {
                perror("Could not get llc occupancy");
                fclose(fp);

                return -1;
        }
        fclose(fp);

        return 0;
}

/*
 * print_results_cache: the cache results are stored in a file
 * @filename:           file that stores the results
 * @bm_pid:             child pid that runs benchmark
 * @llc_value:          perf miss value /
 *                      llc occupancy value reported by resctrl FS
 *
 * Return:              0 on success. non-zero on failure.
 */
static int print_results_cache(char *filename, int bm_pid,
                               unsigned long llc_value)
{
        FILE *fp;

        if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
                printf("Pid: %d \t LLC_value: %lu\n", bm_pid,
                       llc_value);
        } else {
                fp = fopen(filename, "a");
                if (!fp) {
                        perror("Cannot open results file");

                        return errno;
                }
                fprintf(fp, "Pid: %d \t llc_value: %lu\n", bm_pid, llc_value);
                fclose(fp);
        }

        return 0;
}

int measure_cache_vals(struct resctrl_val_param *param, int bm_pid)
{
        unsigned long llc_perf_miss = 0, llc_occu_resc = 0, llc_value = 0;
        int ret;

        /*
         * Measure cache miss from perf.
         */
        if (!strcmp(param->resctrl_val, "cat")) {
                ret = get_llc_perf(&llc_perf_miss);
                if (ret < 0)
                        return ret;
                llc_value = llc_perf_miss;
        }

        /*
         * Measure llc occupancy from resctrl.
         */
        if (!strcmp(param->resctrl_val, "cqm")) {
                ret = get_llc_occu_resctrl(&llc_occu_resc);
                if (ret < 0)
                        return ret;
                llc_value = llc_occu_resc;
        }
        ret = print_results_cache(param->filename, bm_pid, llc_value);
        if (ret)
                return ret;

        return 0;
}

/*
 * cache_val:           execute benchmark and measure LLC occupancy resctrl
 * and perf cache miss for the benchmark
 * @param:              parameters passed to cache_val()
 *
 * Return:              0 on success. non-zero on failure.
 */
int cat_val(struct resctrl_val_param *param)
{
        int malloc_and_init_memory = 1, memflush = 1, operation = 0, ret = 0;
        char *resctrl_val = param->resctrl_val;
        pid_t bm_pid;

        if (strcmp(param->filename, "") == 0)
                sprintf(param->filename, "stdio");

        bm_pid = getpid();

        /* Taskset benchmark to specified cpu */
        ret = taskset_benchmark(bm_pid, param->cpu_no);
        if (ret)
                return ret;

        /* Write benchmark to specified con_mon grp, mon_grp in resctrl FS*/
        ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
                                      resctrl_val);
        if (ret)
                return ret;

        if ((strcmp(resctrl_val, "cat") == 0)) {
                ret = initialize_llc_perf();
                if (ret)
                        return ret;
        }

        /* Test runs until the callback setup() tells the test to stop. */
        while (1) {
                if (strcmp(resctrl_val, "cat") == 0) {
                        ret = param->setup(1, param);
                        if (ret) {
                                ret = 0;
                                break;
                        }
                        ret = reset_enable_llc_perf(bm_pid, param->cpu_no);
                        if (ret)
                                break;

                        if (run_fill_buf(param->span, malloc_and_init_memory,
                                         memflush, operation, resctrl_val)) {
                                fprintf(stderr, "Error-running fill buffer\n");
                                ret = -1;
                                break;
                        }

                        sleep(1);
                        ret = measure_cache_vals(param, bm_pid);
                        if (ret)
                                break;
                } else {
                        break;
                }
        }

        return ret;
}