// SPDX-License-Identifier: GPL-2.0
/*
 * Memory bandwidth monitoring and allocation library
 *
 * Copyright (C) 2018 Intel Corporation
 *
 * Authors:
 *    Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
 *    Fenghua Yu <fenghua.yu@intel.com>
 */
#include "resctrl.h"

#define UNCORE_IMC              "uncore_imc"
#define READ_FILE_NAME          "events/cas_count_read"
#define DYN_PMU_PATH            "/sys/bus/event_source/devices"
#define SCALE                   0.00006103515625
#define MAX_IMCS                20
#define MAX_TOKENS              5

#define CON_MBM_LOCAL_BYTES_PATH                \
        "%s/%s/mon_data/mon_L3_%02d/mbm_local_bytes"

struct membw_read_format {
        __u64 value;         /* The value of the event */
        __u64 time_enabled;  /* if PERF_FORMAT_TOTAL_TIME_ENABLED */
        __u64 time_running;  /* if PERF_FORMAT_TOTAL_TIME_RUNNING */
        __u64 id;            /* if PERF_FORMAT_ID */
};

struct imc_counter_config {
        __u32 type;
        __u64 event;
        __u64 umask;
        struct perf_event_attr pe;
        struct membw_read_format return_value;
        int fd;
};

static char mbm_total_path[1024];
static int imcs;
static struct imc_counter_config imc_counters_config[MAX_IMCS];
static const struct resctrl_test *current_test;

static void read_mem_bw_initialize_perf_event_attr(int i)
{
        memset(&imc_counters_config[i].pe, 0,
               sizeof(struct perf_event_attr));
        imc_counters_config[i].pe.type = imc_counters_config[i].type;
        imc_counters_config[i].pe.size = sizeof(struct perf_event_attr);
        imc_counters_config[i].pe.disabled = 1;
        imc_counters_config[i].pe.inherit = 1;
        imc_counters_config[i].pe.exclude_guest = 0;
        imc_counters_config[i].pe.config =
                imc_counters_config[i].umask << 8 |
                imc_counters_config[i].event;
        imc_counters_config[i].pe.sample_type = PERF_SAMPLE_IDENTIFIER;
        imc_counters_config[i].pe.read_format =
                PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING;
}

static void read_mem_bw_ioctl_perf_event_ioc_reset_enable(int i)
{
        ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_RESET, 0);
        ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_ENABLE, 0);
}

static void read_mem_bw_ioctl_perf_event_ioc_disable(int i)
{
        ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_DISABLE, 0);
}

/*
 * get_read_event_and_umask:    Parse config into event and umask
 * @cas_count_cfg:      Config
 * @count:              iMC number
 */
static void get_read_event_and_umask(char *cas_count_cfg, int count)
{
        char *token[MAX_TOKENS];
        int i = 0;

        token[0] = strtok(cas_count_cfg, "=,");

        for (i = 1; i < MAX_TOKENS; i++)
                token[i] = strtok(NULL, "=,");

        for (i = 0; i < MAX_TOKENS - 1; i++) {
                if (!token[i])
                        break;
                if (strcmp(token[i], "event") == 0)
                        imc_counters_config[count].event = strtol(token[i + 1], NULL, 16);
                if (strcmp(token[i], "umask") == 0)
                        imc_counters_config[count].umask = strtol(token[i + 1], NULL, 16);
        }
}

static int open_perf_read_event(int i, int cpu_no)
{
        imc_counters_config[i].fd =
                perf_event_open(&imc_counters_config[i].pe, -1, cpu_no, -1,
                                PERF_FLAG_FD_CLOEXEC);

        if (imc_counters_config[i].fd == -1) {
                fprintf(stderr, "Error opening leader %llx\n",
                        imc_counters_config[i].pe.config);

                return -1;
        }

        return 0;
}

/* Get type and config of an iMC counter's read event. */
static int read_from_imc_dir(char *imc_dir, int count)
{
        char cas_count_cfg[1024], imc_counter_cfg[1024], imc_counter_type[1024];
        FILE *fp;

        /* Get type of iMC counter */
        sprintf(imc_counter_type, "%s%s", imc_dir, "type");
        fp = fopen(imc_counter_type, "r");
        if (!fp) {
                ksft_perror("Failed to open iMC counter type file");

                return -1;
        }
        if (fscanf(fp, "%u", &imc_counters_config[count].type) <= 0) {
                ksft_perror("Could not get iMC type");
                fclose(fp);

                return -1;
        }
        fclose(fp);

        /* Get read config */
        sprintf(imc_counter_cfg, "%s%s", imc_dir, READ_FILE_NAME);
        fp = fopen(imc_counter_cfg, "r");
        if (!fp) {
                ksft_perror("Failed to open iMC config file");

                return -1;
        }
        if (fscanf(fp, "%1023s", cas_count_cfg) <= 0) {
                ksft_perror("Could not get iMC cas count read");
                fclose(fp);

                return -1;
        }
        fclose(fp);

        get_read_event_and_umask(cas_count_cfg, count);

        return 0;
}

/*
 * A system can have 'n' number of iMC (Integrated Memory Controller)
 * counters, get that 'n'. Discover the properties of the available
 * counters in support of needed performance measurement via perf.
 * For each iMC counter get it's type and config. Also obtain each
 * counter's event and umask for the memory read events that will be
 * measured.
 *
 * Enumerate all these details into an array of structures.
 *
 * Return: >= 0 on success. < 0 on failure.
 */
static int num_of_imcs(void)
{
        char imc_dir[512], *temp;
        unsigned int count = 0;
        struct dirent *ep;
        int ret;
        DIR *dp;

        dp = opendir(DYN_PMU_PATH);
        if (dp) {
                while ((ep = readdir(dp))) {
                        temp = strstr(ep->d_name, UNCORE_IMC);
                        if (!temp)
                                continue;

                        /*
                         * imc counters are named as "uncore_imc_<n>", hence
                         * increment the pointer to point to <n>. Note that
                         * sizeof(UNCORE_IMC) would count for null character as
                         * well and hence the last underscore character in
                         * uncore_imc'_' need not be counted.
                         */
                        temp = temp + sizeof(UNCORE_IMC);

                        /*
                         * Some directories under "DYN_PMU_PATH" could have
                         * names like "uncore_imc_free_running", hence, check if
                         * first character is a numerical digit or not.
                         */
                        if (temp[0] >= '0' && temp[0] <= '9') {
                                sprintf(imc_dir, "%s/%s/", DYN_PMU_PATH,
                                        ep->d_name);
                                ret = read_from_imc_dir(imc_dir, count);
                                if (ret) {
                                        closedir(dp);

                                        return ret;
                                }
                                count++;
                        }
                }
                closedir(dp);
                if (count == 0) {
                        ksft_print_msg("Unable to find iMC counters\n");

                        return -1;
                }
        } else {
                ksft_perror("Unable to open PMU directory");

                return -1;
        }

        return count;
}

int initialize_read_mem_bw_imc(void)
{
        int imc;

        imcs = num_of_imcs();
        if (imcs <= 0)
                return imcs;

        /* Initialize perf_event_attr structures for all iMC's */
        for (imc = 0; imc < imcs; imc++)
                read_mem_bw_initialize_perf_event_attr(imc);

        return 0;
}

static void perf_close_imc_read_mem_bw(void)
{
        int mc;

        for (mc = 0; mc < imcs; mc++) {
                if (imc_counters_config[mc].fd != -1)
                        close(imc_counters_config[mc].fd);
        }
}

/*
 * perf_open_imc_read_mem_bw - Open perf fds for IMCs
 * @cpu_no: CPU number that the benchmark PID is bound to
 *
 * Return: = 0 on success. < 0 on failure.
 */
static int perf_open_imc_read_mem_bw(int cpu_no)
{
        int imc, ret;

        for (imc = 0; imc < imcs; imc++)
                imc_counters_config[imc].fd = -1;

        for (imc = 0; imc < imcs; imc++) {
                ret = open_perf_read_event(imc, cpu_no);
                if (ret)
                        goto close_fds;
        }

        return 0;

close_fds:
        perf_close_imc_read_mem_bw();
        return -1;
}

/*
 * do_imc_read_mem_bw_test - Perform memory bandwidth test
 *
 * Runs memory bandwidth test over one second period. Also, handles starting
 * and stopping of the IMC perf counters around the test.
 */
static void do_imc_read_mem_bw_test(void)
{
        int imc;

        for (imc = 0; imc < imcs; imc++)
                read_mem_bw_ioctl_perf_event_ioc_reset_enable(imc);

        sleep(1);

        /* Stop counters after a second to get results. */
        for (imc = 0; imc < imcs; imc++)
                read_mem_bw_ioctl_perf_event_ioc_disable(imc);
}

/*
 * get_read_mem_bw_imc - Memory read bandwidth as reported by iMC counters
 *
 * Memory read bandwidth utilized by a process on a socket can be calculated
 * using iMC counters' read events. Perf events are used to read these
 * counters.
 *
 * Return: = 0 on success. < 0 on failure.
 */
static int get_read_mem_bw_imc(float *bw_imc)
{
        float reads = 0, of_mul_read = 1;
        int imc;

        /*
         * Log read event values from all iMC counters into
         * struct imc_counter_config.
         * Take overflow into consideration before calculating total bandwidth.
         */
        for (imc = 0; imc < imcs; imc++) {
                struct imc_counter_config *r =
                        &imc_counters_config[imc];

                if (read(r->fd, &r->return_value,
                         sizeof(struct membw_read_format)) == -1) {
                        ksft_perror("Couldn't get read bandwidth through iMC");
                        return -1;
                }

                __u64 r_time_enabled = r->return_value.time_enabled;
                __u64 r_time_running = r->return_value.time_running;

                if (r_time_enabled != r_time_running)
                        of_mul_read = (float)r_time_enabled /
                                        (float)r_time_running;

                reads += r->return_value.value * of_mul_read * SCALE;
        }

        *bw_imc = reads;
        return 0;
}

/*
 * initialize_mem_bw_resctrl:   Appropriately populate "mbm_total_path"
 * @param:      Parameters passed to resctrl_val()
 * @domain_id:  Domain ID (cache ID; for MB, L3 cache ID)
 */
void initialize_mem_bw_resctrl(const struct resctrl_val_param *param,
                               int domain_id)
{
        sprintf(mbm_total_path, CON_MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
                param->ctrlgrp, domain_id);
}

/*
 * Open file to read MBM local bytes from resctrl FS
 */
static FILE *open_mem_bw_resctrl(const char *mbm_bw_file)
{
        FILE *fp;

        fp = fopen(mbm_bw_file, "r");
        if (!fp)
                ksft_perror("Failed to open total memory bandwidth file");

        return fp;
}

/*
 * Get MBM Local bytes as reported by resctrl FS
 */
static int get_mem_bw_resctrl(FILE *fp, unsigned long *mbm_total)
{
        if (fscanf(fp, "%lu\n", mbm_total) <= 0) {
                ksft_perror("Could not get MBM local bytes");
                return -1;
        }
        return 0;
}

static pid_t bm_pid;

void ctrlc_handler(int signum, siginfo_t *info, void *ptr)
{
        /* Only kill child after bm_pid is set after fork() */
        if (bm_pid)
                kill(bm_pid, SIGKILL);
        umount_resctrlfs();
        if (current_test && current_test->cleanup)
                current_test->cleanup();
        ksft_print_msg("Ending\n\n");

        exit(EXIT_SUCCESS);
}

/*
 * Register CTRL-C handler for parent, as it has to kill
 * child process before exiting.
 */
int signal_handler_register(const struct resctrl_test *test)
{
        struct sigaction sigact = {};
        int ret = 0;

        bm_pid = 0;

        current_test = test;
        sigact.sa_sigaction = ctrlc_handler;
        sigemptyset(&sigact.sa_mask);
        sigact.sa_flags = SA_SIGINFO;
        if (sigaction(SIGINT, &sigact, NULL) ||
            sigaction(SIGTERM, &sigact, NULL) ||
            sigaction(SIGHUP, &sigact, NULL)) {
                ksft_perror("sigaction");
                ret = -1;
        }
        return ret;
}

/*
 * Reset signal handler to SIG_DFL.
 * Non-Value return because the caller should keep
 * the error code of other path even if sigaction fails.
 */
void signal_handler_unregister(void)
{
        struct sigaction sigact = {};

        current_test = NULL;
        sigact.sa_handler = SIG_DFL;
        sigemptyset(&sigact.sa_mask);
        if (sigaction(SIGINT, &sigact, NULL) ||
            sigaction(SIGTERM, &sigact, NULL) ||
            sigaction(SIGHUP, &sigact, NULL)) {
                ksft_perror("sigaction");
        }
}

/*
 * print_results_bw:    the memory bandwidth results are stored in a file
 * @filename:           file that stores the results
 * @bm_pid:             child pid that runs benchmark
 * @bw_imc:             perf imc counter value
 * @bw_resc:            memory bandwidth value
 *
 * Return:              0 on success, < 0 on error.
 */
static int print_results_bw(char *filename, pid_t bm_pid, float bw_imc,
                            unsigned long bw_resc)
{
        unsigned long diff = fabs(bw_imc - bw_resc);
        FILE *fp;

        if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
                printf("Pid: %d \t Mem_BW_iMC: %f \t ", (int)bm_pid, bw_imc);
                printf("Mem_BW_resc: %lu \t Difference: %lu\n", bw_resc, diff);
        } else {
                fp = fopen(filename, "a");
                if (!fp) {
                        ksft_perror("Cannot open results file");

                        return -1;
                }
                if (fprintf(fp, "Pid: %d \t Mem_BW_iMC: %f \t Mem_BW_resc: %lu \t Difference: %lu\n",
                            (int)bm_pid, bw_imc, bw_resc, diff) <= 0) {
                        ksft_print_msg("Could not log results\n");
                        fclose(fp);

                        return -1;
                }
                fclose(fp);
        }

        return 0;
}

/*
 * measure_read_mem_bw - Measures read memory bandwidth numbers while benchmark runs
 * @uparams:            User supplied parameters
 * @param:              Parameters passed to resctrl_val()
 * @bm_pid:             PID that runs the benchmark
 *
 * Measure memory bandwidth from resctrl and from another source which is
 * perf imc value or could be something else if perf imc event is not
 * available. Compare the two values to validate resctrl value. It takes
 * 1 sec to measure the data.
 * resctrl does not distinguish between read and write operations so
 * its data includes all memory operations.
 */
int measure_read_mem_bw(const struct user_params *uparams,
                        struct resctrl_val_param *param, pid_t bm_pid)
{
        unsigned long bw_resc, bw_resc_start, bw_resc_end;
        FILE *mem_bw_fp;
        float bw_imc;
        int ret;

        mem_bw_fp = open_mem_bw_resctrl(mbm_total_path);
        if (!mem_bw_fp)
                return -1;

        ret = perf_open_imc_read_mem_bw(uparams->cpu);
        if (ret < 0)
                goto close_fp;

        ret = get_mem_bw_resctrl(mem_bw_fp, &bw_resc_start);
        if (ret < 0)
                goto close_imc;

        rewind(mem_bw_fp);

        do_imc_read_mem_bw_test();

        ret = get_mem_bw_resctrl(mem_bw_fp, &bw_resc_end);
        if (ret < 0)
                goto close_imc;

        ret = get_read_mem_bw_imc(&bw_imc);
        if (ret < 0)
                goto close_imc;

        perf_close_imc_read_mem_bw();
        fclose(mem_bw_fp);

        bw_resc = (bw_resc_end - bw_resc_start) / MB;

        return print_results_bw(param->filename, bm_pid, bw_imc, bw_resc);

close_imc:
        perf_close_imc_read_mem_bw();
close_fp:
        fclose(mem_bw_fp);
        return ret;
}

/*
 * resctrl_val: execute benchmark and measure memory bandwidth on
 *                      the benchmark
 * @test:               test information structure
 * @uparams:            user supplied parameters
 * @param:              parameters passed to resctrl_val()
 *
 * Return:              0 when the test was run, < 0 on error.
 */
int resctrl_val(const struct resctrl_test *test,
                const struct user_params *uparams,
                struct resctrl_val_param *param)
{
        unsigned char *buf = NULL;
        cpu_set_t old_affinity;
        int domain_id;
        int ret = 0;
        pid_t ppid;

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

        ret = get_domain_id(test->resource, uparams->cpu, &domain_id);
        if (ret < 0) {
                ksft_print_msg("Could not get domain ID\n");
                return ret;
        }

        ppid = getpid();

        /* Taskset test to specified CPU. */
        ret = taskset_benchmark(ppid, uparams->cpu, &old_affinity);
        if (ret)
                return ret;

        /* Write test to specified control & monitoring group in resctrl FS. */
        ret = write_bm_pid_to_resctrl(ppid, param->ctrlgrp, param->mongrp);
        if (ret)
                goto reset_affinity;

        if (param->init) {
                ret = param->init(param, domain_id);
                if (ret)
                        goto reset_affinity;
        }

        /*
         * If not running user provided benchmark, run the default
         * "fill_buf". First phase of "fill_buf" is to prepare the
         * buffer that the benchmark will operate on. No measurements
         * are needed during this phase and prepared memory will be
         * passed to next part of benchmark via copy-on-write thus
         * no impact on the benchmark that relies on reading from
         * memory only.
         */
        if (param->fill_buf) {
                buf = alloc_buffer(param->fill_buf->buf_size,
                                   param->fill_buf->memflush);
                if (!buf) {
                        ret = -ENOMEM;
                        goto reset_affinity;
                }
        }

        fflush(stdout);
        bm_pid = fork();
        if (bm_pid == -1) {
                ret = -errno;
                ksft_perror("Unable to fork");
                goto free_buf;
        }

        /*
         * What needs to be measured runs in separate process until
         * terminated.
         */
        if (bm_pid == 0) {
                if (param->fill_buf)
                        fill_cache_read(buf, param->fill_buf->buf_size, false);
                else if (uparams->benchmark_cmd[0])
                        execvp(uparams->benchmark_cmd[0], (char **)uparams->benchmark_cmd);
                exit(EXIT_SUCCESS);
        }

        ksft_print_msg("Benchmark PID: %d\n", (int)bm_pid);

        /* Give benchmark enough time to fully run. */
        sleep(1);

        /* Test runs until the callback setup() tells the test to stop. */
        while (1) {
                ret = param->setup(test, uparams, param);
                if (ret == END_OF_TESTS) {
                        ret = 0;
                        break;
                }
                if (ret < 0)
                        break;

                ret = param->measure(uparams, param, bm_pid);
                if (ret)
                        break;
        }

        kill(bm_pid, SIGKILL);
free_buf:
        free(buf);
reset_affinity:
        taskset_restore(ppid, &old_affinity);
        return ret;
}