// SPDX-License-Identifier: GPL-2.0
/*
 * Cache Allocation Technology (CAT) test
 *
 * Copyright (C) 2018 Intel Corporation
 *
 * Authors:
 *    Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
 *    Fenghua Yu <fenghua.yu@intel.com>
 */
#include "resctrl.h"
#include <unistd.h>

#define RESULT_FILE_NAME1       "result_cat1"
#define RESULT_FILE_NAME2       "result_cat2"
#define NUM_OF_RUNS             5
#define MAX_DIFF_PERCENT        4
#define MAX_DIFF                1000000

int count_of_bits;
char cbm_mask[256];
unsigned long long_mask;
unsigned long cache_size;

/*
 * Change schemata. Write schemata to specified
 * con_mon grp, mon_grp in resctrl FS.
 * Run 5 times in order to get average values.
 */
static int cat_setup(int num, ...)
{
        struct resctrl_val_param *p;
        char schemata[64];
        va_list param;
        int ret = 0;

        va_start(param, num);
        p = va_arg(param, struct resctrl_val_param *);
        va_end(param);

        /* Run NUM_OF_RUNS times */
        if (p->num_of_runs >= NUM_OF_RUNS)
                return -1;

        if (p->num_of_runs == 0) {
                sprintf(schemata, "%lx", p->mask);
                ret = write_schemata(p->ctrlgrp, schemata, p->cpu_no,
                                     p->resctrl_val);
        }
        p->num_of_runs++;

        return ret;
}

static void show_cache_info(unsigned long sum_llc_perf_miss, int no_of_bits,
                            unsigned long span)
{
        unsigned long allocated_cache_lines = span / 64;
        unsigned long avg_llc_perf_miss = 0;
        float diff_percent;

        avg_llc_perf_miss = sum_llc_perf_miss / (NUM_OF_RUNS - 1);
        diff_percent = ((float)allocated_cache_lines - avg_llc_perf_miss) /
                                allocated_cache_lines * 100;

        printf("%sok CAT: cache miss rate within %d%%\n",
               !is_amd && abs((int)diff_percent) > MAX_DIFF_PERCENT ?
               "not " : "", MAX_DIFF_PERCENT);
        tests_run++;
        printf("# Percent diff=%d\n", abs((int)diff_percent));
        printf("# Number of bits: %d\n", no_of_bits);
        printf("# Avg_llc_perf_miss: %lu\n", avg_llc_perf_miss);
        printf("# Allocated cache lines: %lu\n", allocated_cache_lines);
}

static int check_results(struct resctrl_val_param *param)
{
        char *token_array[8], temp[512];
        unsigned long sum_llc_perf_miss = 0;
        int runs = 0, no_of_bits = 0;
        FILE *fp;

        printf("# Checking for pass/fail\n");
        fp = fopen(param->filename, "r");
        if (!fp) {
                perror("# Cannot open file");

                return errno;
        }

        while (fgets(temp, sizeof(temp), fp)) {
                char *token = strtok(temp, ":\t");
                int fields = 0;

                while (token) {
                        token_array[fields++] = token;
                        token = strtok(NULL, ":\t");
                }
                /*
                 * Discard the first value which is inaccurate due to monitoring
                 * setup transition phase.
                 */
                if (runs > 0)
                        sum_llc_perf_miss += strtoul(token_array[3], NULL, 0);
                runs++;
        }

        fclose(fp);
        no_of_bits = count_bits(param->mask);

        show_cache_info(sum_llc_perf_miss, no_of_bits, param->span);

        return 0;
}

void cat_test_cleanup(void)
{
        remove(RESULT_FILE_NAME1);
        remove(RESULT_FILE_NAME2);
}

int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
{
        unsigned long l_mask, l_mask_1;
        int ret, pipefd[2], sibling_cpu_no;
        char pipe_message;
        pid_t bm_pid;

        cache_size = 0;

        ret = remount_resctrlfs(true);
        if (ret)
                return ret;

        if (!validate_resctrl_feature_request("cat"))
                return -1;

        /* Get default cbm mask for L3/L2 cache */
        ret = get_cbm_mask(cache_type);
        if (ret)
                return ret;

        long_mask = strtoul(cbm_mask, NULL, 16);

        /* Get L3/L2 cache size */
        ret = get_cache_size(cpu_no, cache_type, &cache_size);
        if (ret)
                return ret;
        printf("cache size :%lu\n", cache_size);

        /* Get max number of bits from default-cabm mask */
        count_of_bits = count_bits(long_mask);

        if (n < 1 || n > count_of_bits - 1) {
                printf("Invalid input value for no_of_bits n!\n");
                printf("Please Enter value in range 1 to %d\n",
                       count_of_bits - 1);
                return -1;
        }

        /* Get core id from same socket for running another thread */
        sibling_cpu_no = get_core_sibling(cpu_no);
        if (sibling_cpu_no < 0)
                return -1;

        struct resctrl_val_param param = {
                .resctrl_val    = "cat",
                .cpu_no         = cpu_no,
                .mum_resctrlfs  = 0,
                .setup          = cat_setup,
        };

        l_mask = long_mask >> n;
        l_mask_1 = ~l_mask & long_mask;

        /* Set param values for parent thread which will be allocated bitmask
         * with (max_bits - n) bits
         */
        param.span = cache_size * (count_of_bits - n) / count_of_bits;
        strcpy(param.ctrlgrp, "c2");
        strcpy(param.mongrp, "m2");
        strcpy(param.filename, RESULT_FILE_NAME2);
        param.mask = l_mask;
        param.num_of_runs = 0;

        if (pipe(pipefd)) {
                perror("# Unable to create pipe");
                return errno;
        }

        bm_pid = fork();

        /* Set param values for child thread which will be allocated bitmask
         * with n bits
         */
        if (bm_pid == 0) {
                param.mask = l_mask_1;
                strcpy(param.ctrlgrp, "c1");
                strcpy(param.mongrp, "m1");
                param.span = cache_size * n / count_of_bits;
                strcpy(param.filename, RESULT_FILE_NAME1);
                param.num_of_runs = 0;
                param.cpu_no = sibling_cpu_no;
        }

        remove(param.filename);

        ret = cat_val(&param);
        if (ret)
                return ret;

        ret = check_results(&param);
        if (ret)
                return ret;

        if (bm_pid == 0) {
                /* Tell parent that child is ready */
                close(pipefd[0]);
                pipe_message = 1;
                if (write(pipefd[1], &pipe_message, sizeof(pipe_message)) <
                    sizeof(pipe_message)) {
                        close(pipefd[1]);
                        perror("# failed signaling parent process");
                        return errno;
                }

                close(pipefd[1]);
                while (1)
                        ;
        } else {
                /* Parent waits for child to be ready. */
                close(pipefd[1]);
                pipe_message = 0;
                while (pipe_message != 1) {
                        if (read(pipefd[0], &pipe_message,
                                 sizeof(pipe_message)) < sizeof(pipe_message)) {
                                perror("# failed reading from child process");
                                break;
                        }
                }
                close(pipefd[0]);
                kill(bm_pid, SIGKILL);
        }

        cat_test_cleanup();
        if (bm_pid)
                umount_resctrlfs();

        return 0;
}