path: root/plpa-1.3.2/src/libplpa/plpa_map.c

/*
 * Copyright (c) 2007-2008 Cisco Systems, Inc.  All rights reserved.
 *
 * Portions of this file originally contributed by Advanced Micro
 * Devices, Inc.  See notice below.
 */
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#include "plpa_config.h"
#include "plpa.h"
#include "plpa_internal.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <limits.h>
#include <errno.h>
#include <stdlib.h>
#include <stdbool.h>

typedef struct tuple_t_ {
    int processor_id, socket_id, core_id, online;
} tuple_t;

static const char *sysfs_mount = "/sys";
static int supported = 0;
static int num_processors = -1;
static int max_processor_id = -1;
static int num_sockets = -1;
static int max_socket_id = -1;
static int *max_core_id = NULL;
static int *num_cores = NULL;
static int max_core_id_overall = -1;
static tuple_t *map_processor_id_to_tuple = NULL;
static tuple_t **map_tuple_to_processor_id = NULL;
static PLPA_NAME(cache_behavior_t) cache_behavior = PLPA_NAME_CAPS(CACHE_IGNORE);

static void clear_cache(void)
{
    if (NULL != max_core_id) {
        free(max_core_id);
        max_core_id = NULL;
    }
    if (NULL != num_cores) {
        free(num_cores);
        num_cores = NULL;
    }
    if (NULL != map_processor_id_to_tuple) {
        free(map_processor_id_to_tuple);
        map_processor_id_to_tuple = NULL;
    }
    if (NULL != map_tuple_to_processor_id) {
        free(map_tuple_to_processor_id);
        map_tuple_to_processor_id = NULL;
    }

    num_processors = max_processor_id = -1;
    num_sockets = max_socket_id = -1;
    max_core_id_overall = -1;
}

static void load_cache(void)
{
    int i, j, k, invalid_entry, fd, found_online;
    char path[PATH_MAX], buf[8];
    PLPA_NAME(cpu_set_t) valid_processors;
    PLPA_NAME(cpu_set_t) *cores_on_sockets;
    int found;
    DIR *dir;
    struct dirent dentry, *dentryp = NULL;

#if PLPA_DEBUG
    char *temp = getenv("PLPA_SYSFS_MOUNT");
    if (temp) {
        sysfs_mount = temp;
    }
#endif

    /* Check for the parent directory */
    sprintf(path, "%s/devices/system/cpu", sysfs_mount);
    if (access(path, R_OK|X_OK)) {
        return;
    }

    dir = opendir(path);
    if (NULL == dir) {
        return;
    }

    /* Catch all entries of format "cpu%d", count them and maintain
       max_processor_id */
    num_processors = 0;
    PLPA_CPU_ZERO(&valid_processors);
    do {
        int ret = readdir_r(dir, &dentry, &dentryp);
        if (0 != ret) {
            closedir(dir);
            clear_cache();
            return;
        }

        if (dentryp) {
            int cpuid;

            ret = sscanf(dentryp->d_name, "cpu%d", &cpuid);
            if (1 == ret) {
                ++num_processors;
                if (cpuid >= PLPA_BITMASK_CPU_MAX) {
                    closedir(dir);
                    clear_cache();
                    return;
                } else if (cpuid > max_processor_id) {
                    max_processor_id = cpuid;
                }
                PLPA_CPU_SET(cpuid, &valid_processors);
            }
        }
    } while (NULL != dentryp);
    closedir(dir);

    /* If we found no processors, then we have no topology info */
    if (0 == num_processors) {
        clear_cache();
        return;
    }

    /* Malloc space for the first map (processor ID -> tuple).
       Include enough space for one invalid entry. */
    map_processor_id_to_tuple = malloc(sizeof(tuple_t) * 
                                       (max_processor_id + 2));
    if (NULL == map_processor_id_to_tuple) {
        clear_cache();
        return;
    }
    for (i = 0; i <= max_processor_id; ++i) {
        if (PLPA_CPU_ISSET(i, &valid_processors)) {
            map_processor_id_to_tuple[i].processor_id = i;
        } else {
            map_processor_id_to_tuple[i].processor_id = -1;
        }
        map_processor_id_to_tuple[i].socket_id = -1;
        map_processor_id_to_tuple[i].core_id = -1;
    }
    /* Set the invalid entry */
    invalid_entry = i;
    map_processor_id_to_tuple[invalid_entry].processor_id = -1;
    map_processor_id_to_tuple[invalid_entry].socket_id = -1;
    map_processor_id_to_tuple[invalid_entry].core_id = -1;

    /* Build a cached map of (socket,core) tuples */
    for (found = 0, i = 0; i <= max_processor_id; ++i) {

        /* Check for invalid processor ID */
        if (map_processor_id_to_tuple[i].processor_id < 0) {
            continue;
        }

        /* Read the "online" state for this processor.  If the online
           file is not there, then the kernel likely doesn't have
           hotplug support so just assume that it's online.  Some notes:

           - the perms on the "online" file are root/600, so only root
             will see this info
           - if online is 0, then all the topology files disappear (!)
             -- so PLPA needs to compensate for that
        */
        found_online = 0;
        sprintf(path, "%s/devices/system/cpu/cpu%d/online", 
                sysfs_mount, i);
        fd = open(path, O_RDONLY);
        memset(buf, 0, sizeof(buf));
        if (fd >= 0 && read(fd, buf, sizeof(buf) - 1) > 0) {
            found_online = 1;
            sscanf(buf, "%d", &(map_processor_id_to_tuple[i].online));
        } else {
            map_processor_id_to_tuple[i].online = 1;
        }
        if (fd >= 0) {
            close(fd);
        }

        /* Core ID */
        sprintf(path, "%s/devices/system/cpu/cpu%d/topology/core_id", 
                sysfs_mount, i);
        fd = open(path, O_RDONLY);
        if (fd >= 0) {
            memset(buf, 0, sizeof(buf));
            if (read(fd, buf, sizeof(buf) - 1) > 0) {
                sscanf(buf, "%d", &(map_processor_id_to_tuple[i].core_id));
            } else {
                map_processor_id_to_tuple[i].core_id = -1;
            }
            close(fd);
        } 
        /* Special case: we didn't find the core_id file, but we *did*
           find the online file and the processor is offline -- then
           just mark the core ID as "unknown" and keep going (because
           if a processor is offline, the core_id file won't exist --
           grumble) */
        else if (found_online && 0 == map_processor_id_to_tuple[i].online) {
            map_processor_id_to_tuple[i].core_id = -1;
        }

        /* Socket ID */
        sprintf(path,
                "%s/devices/system/cpu/cpu%d/topology/physical_package_id",
                sysfs_mount, i);
        fd = open(path, O_RDONLY);
        if (fd >= 0) {
            memset(buf, 0, sizeof(buf));
            if (read(fd, buf, sizeof(buf) - 1) > 0) {
                sscanf(buf, "%d", &(map_processor_id_to_tuple[i].socket_id));
            }
            close(fd);
            found = 1;
        }
        /* Special case: we didn't find the socket_id file, but we
           *did* find the online file and the processor is offline --
           then just mark the socket ID as "unknown" and keep going
           (because if a processor is offline, the socket_id file won't
           exist -- grumble) */
        else if (found_online && 0 == map_processor_id_to_tuple[i].online) {
            map_processor_id_to_tuple[i].socket_id = -1;
        }
        
        /* Keep a running tab on the max socket number */
        if (map_processor_id_to_tuple[i].socket_id > max_socket_id) {
            max_socket_id = map_processor_id_to_tuple[i].socket_id;
        }
    }

    /* If we didn't find any core_id/physical_package_id's, then we
       don't have the topology info */
    if (!found) {
        clear_cache();
        return;
    }

    /* Now that we know the max number of sockets, allocate some
       arrays */
    max_core_id = malloc(sizeof(int) * (max_socket_id + 1));
    if (NULL == max_core_id) {
        clear_cache();
        return;
    }
    num_cores = malloc(sizeof(int) * (max_socket_id + 1));
    if (NULL == num_cores) {
        clear_cache();
        return;
    }
    for (i = 0; i <= max_socket_id; ++i) {
        num_cores[i] = -1;
        max_core_id[i] = -1;
    }

    /* Find the max core number on each socket */
    for (i = 0; i <= max_processor_id; ++i) {
        if (map_processor_id_to_tuple[i].processor_id < 0 ||
            map_processor_id_to_tuple[i].socket_id < 0) {
            continue;
        }
        if (map_processor_id_to_tuple[i].core_id > 
            max_core_id[map_processor_id_to_tuple[i].socket_id]) {
            max_core_id[map_processor_id_to_tuple[i].socket_id] = 
                map_processor_id_to_tuple[i].core_id;
        }
        if (max_core_id[map_processor_id_to_tuple[i].socket_id] > 
            max_core_id_overall) {
            max_core_id_overall = 
                max_core_id[map_processor_id_to_tuple[i].socket_id];
        }
    }

    /* Go through and count the number of unique sockets found.  It
       may not be the same as max_socket_id because there may be
       "holes" -- e.g., sockets 0 and 3 are used, but sockets 1 and 2
       are empty. */
    for (j = i = 0; i <= max_socket_id; ++i) {
        if (max_core_id[i] >= 0) {
            ++j;
        }
    }
    if (j > 0) {
        num_sockets = j;
    }

    /* Count how many cores are available on each socket.  This may
       not be the same as max_core_id[socket_num] if there are
       "holes".  I don't know if holes can happen (i.e., if specific
       cores can be taken offline), but what the heck... */
    cores_on_sockets = malloc(sizeof(PLPA_NAME(cpu_set_t)) * 
                              (max_socket_id + 1));
    if (NULL == cores_on_sockets) {
        clear_cache();
        return;
    }
    for (i = 0; i <= max_socket_id; ++i) {
        PLPA_CPU_ZERO(&(cores_on_sockets[i]));
    }
    for (i = 0; i <= max_processor_id; ++i) {
        if (map_processor_id_to_tuple[i].socket_id >= 0) {
            PLPA_CPU_SET(map_processor_id_to_tuple[i].core_id,
                         &(cores_on_sockets[map_processor_id_to_tuple[i].socket_id]));
        }
    }
    for (i = 0; i <= max_socket_id; ++i) {
        int count = 0;
        for (j = 0; j <= max_core_id[i]; ++j) {
            if (PLPA_CPU_ISSET(j, &(cores_on_sockets[i]))) {
                ++count;
            }
        }
        if (count > 0) {
            num_cores[i] = count;
        }
    }
    free(cores_on_sockets);

    /* Now go through and build the map in the other direction:
       (socket,core) => processor_id.  This map simply points to
       entries in the other map (i.e., it's by reference instead of by
       value). */
    map_tuple_to_processor_id = malloc(sizeof(tuple_t *) *
                                       ((max_socket_id + 1) *
                                        (max_core_id_overall + 1)));
    if (NULL == map_tuple_to_processor_id) {
        clear_cache();
        return;
    }
    /* Compute map */
    for (i = 0; i <= max_socket_id; ++i) {
        for (j = 0; j <= max_core_id_overall; ++j) {
            tuple_t **tuple_ptr = &map_tuple_to_processor_id[
                                   i * (max_core_id_overall + 1) + j];

            /* Default to the invalid entry in the other map, meaning
               that this (socket,core) combination doesn't exist
               (e.g., the core number does not exist in this socket,
               although it does exist in other sockets). */
            *tuple_ptr = &map_processor_id_to_tuple[invalid_entry];

            /* See if this (socket,core) tuple exists in the other
               map.  If so, set this entry to point to it (overriding
               the invalid entry default). */
            for (k = 0; k <= max_processor_id; ++k) {
                if (map_processor_id_to_tuple[k].socket_id == i &&
                    map_processor_id_to_tuple[k].core_id == j) {
                    *tuple_ptr = &map_processor_id_to_tuple[k];
#if defined(PLPA_DEBUG) && PLPA_DEBUG
                    printf("Creating map [%d]: (socket %d, core %d) -> ID %d\n",
                           i * (max_core_id_overall + 1) + j,
                           i, j, k);
#endif
                    break;
                }
            }
        }
    }

    supported = 1;
}

static int cache_action(void)
{
    switch (cache_behavior) {
    case PLPA_NAME_CAPS(CACHE_USE):
        if (NULL == map_processor_id_to_tuple) {
            load_cache();
        }
        break;

    case PLPA_NAME_CAPS(CACHE_IGNORE):
        clear_cache();
        load_cache();
        break;

    default:
        return EINVAL;
    }

    return 0;
}

/* Return whether this kernel supports topology information or not */
int PLPA_NAME(have_topology_information)(int *supported_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == supported_arg) {
        return EINVAL;
    }

    *supported_arg = supported;
    return 0;
}

int PLPA_NAME(map_to_processor_id)(int socket_id, int core_id, 
                                   int *processor_id)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == processor_id) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for some invalid entries */
    if (socket_id < 0 || socket_id > max_socket_id ||
        core_id < 0 || core_id > max_core_id[socket_id]) {
        return ENOENT;
    }
    /* If the mapping returns -1, then this is a non-existent
       socket/core combo (even though they fall within the max socket
       / max core overall values) */
    ret = map_tuple_to_processor_id[socket_id * (max_core_id_overall + 1) +
                                    core_id]->processor_id;
    if (-1 == ret) {
        return ENOENT;
    }

    /* Ok, all should be good -- return the mapping */
    *processor_id = ret;
    return 0;
}

int PLPA_NAME(map_to_socket_core)(int processor_id, 
                                  int *socket_id, int *core_id)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == socket_id || NULL == core_id) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for some invalid entries */
    if (processor_id < 0 || processor_id > max_processor_id ||
        map_processor_id_to_tuple[processor_id].processor_id < 0) {
        return ENOENT;
    }
    ret = map_processor_id_to_tuple[processor_id].socket_id;
    if (-1 == ret) {
        return ENOENT;
    }

    /* Ok, all should be good -- return the mapping */
    *socket_id = ret;
    *core_id = map_processor_id_to_tuple[processor_id].core_id;
    return 0;
}

/* Deprecated function */
int PLPA_NAME(get_processor_info)(int *num_processors_arg,
                                  int *max_processor_id_arg)
{
    return PLPA_NAME(get_processor_data)(PLPA_NAME_CAPS(COUNT_ALL),
                                         num_processors_arg,
                                         max_processor_id_arg);
}

int PLPA_NAME(get_processor_data)(PLPA_NAME(count_specification_t) count_spec,
                                  int *num_processors_arg,
                                  int *max_processor_id_arg)
{
    int i, ret;
    bool match;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for bozo arguments */
    if (NULL == max_processor_id_arg || NULL == num_processors_arg) {
        return EINVAL;
    }

    /* If we wanted all processors, we're done */
    if (PLPA_NAME_CAPS(COUNT_ALL) == count_spec) {
        *num_processors_arg = num_processors;
        *max_processor_id_arg = max_processor_id;
    } else {
        /* Otherwise, count the appropriate type */
        *num_processors_arg = 0;
        *max_processor_id_arg = 0;
        for (i = 0; i <= max_processor_id; ++i) {
            if (map_processor_id_to_tuple[i].processor_id >= 0) {
                match = false;
                switch (count_spec) {
                case PLPA_NAME_CAPS(COUNT_ONLINE):
                    if (map_processor_id_to_tuple[i].online) {
                        match = true;
                    }
                    break;

                case PLPA_NAME_CAPS(COUNT_OFFLINE):
                    if (!map_processor_id_to_tuple[i].online) {
                        match = true;
                    }
                    break;
                default:
                    /* Just so that compilers don't complain */
                    break;
                }
                if (match) {
                    ++(*num_processors_arg);
                    if (*max_processor_id_arg < 
                        map_processor_id_to_tuple[i].processor_id) {
                        *max_processor_id_arg =
                            map_processor_id_to_tuple[i].processor_id;
                    }
                }
            }
        }
    }
    return 0;
}

/* Returns the Linux processor ID for the Nth processor (starting with
   0). */
int PLPA_NAME(get_processor_id)(int processor_num, 
                                PLPA_NAME(count_specification_t) count_spec,
                                int *processor_id)
{
    int ret, i, count;
    bool match;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == processor_id) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for out of range params */
    if (processor_num < 0 || processor_num > num_processors) {
        return EINVAL;
    }

    /* Find the processor_num'th processor */
    for (count = i = 0; i <= max_processor_id; ++i) {
        if (map_processor_id_to_tuple[i].processor_id >= 0) {
            match = false;
            switch (count_spec) {
            case PLPA_NAME_CAPS(COUNT_ONLINE):
                if (map_processor_id_to_tuple[i].online) {
                    match = true;
                }
                break;

            case PLPA_NAME_CAPS(COUNT_OFFLINE):
                if (!map_processor_id_to_tuple[i].online) {
                    match = true;
                }
                break;

            case PLPA_NAME_CAPS(COUNT_ALL):
                match = true;
                break;
            }
            if (match) {
                if (count++ == processor_num) {
                    *processor_id = map_processor_id_to_tuple[i].processor_id;
                    return 0;
                }
            }
        }
    }

    /* Didn't find it */
    return ENODEV;
}

/* Check to see if a given Linux processor ID exists / is online.
   Returns 0 on success. */
int PLPA_NAME(get_processor_flags)(int processor_id, 
                                   int *exists_arg, int *online_arg)
{
    int ret, exists, online;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == exists_arg && NULL == online_arg) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for out of range params */
    if (processor_id < 0 || processor_id > max_processor_id) {
        return EINVAL;
    }

    exists = online = 0;
    if (processor_id == map_processor_id_to_tuple[processor_id].processor_id) {
        exists = 1;
        if (map_processor_id_to_tuple[processor_id].online) {
            online = 1;
        }
    }
    if (NULL != exists_arg) {
        *exists_arg = exists;
    }
    if (NULL != online_arg) {
        *online_arg = online;
    }

    return 0;
}

/* Return the max socket number */
int PLPA_NAME(get_socket_info)(int *num_sockets_arg, int *max_socket_id_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for bozo arguments */
    if (NULL == max_socket_id_arg || NULL == num_sockets_arg) {
        return EINVAL;
    }

    /* All done */
    *num_sockets_arg = num_sockets;
    *max_socket_id_arg = max_socket_id;
    return 0;
}

/* Returns the Linux socket ID for the Nth socket (starting with 0). */
int PLPA_NAME(get_socket_id)(int socket_num, int *socket_id)
{
    int ret, i, j, k, count;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == socket_id) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for out of range params */
    if (socket_num < 0 || socket_num > num_sockets) {
        return EINVAL;
    }

    /* Find the socket_num'th socket */
    for (count = i = 0; i <= max_socket_id; ++i) {
        /* See if any core in this socket is active.  If so, count
           this socket */
        for (j = 0; j <= max_core_id_overall; ++j) {
            k = i * (max_core_id_overall + 1) + j;
            if (map_tuple_to_processor_id[k]->processor_id >= 0) {
                if (count++ == socket_num) {
                    *socket_id = map_tuple_to_processor_id[k]->socket_id;
                    return 0;
                }
                /* Ok, we found one -- skip to the end of this socket */
                j = max_core_id_overall + 1;
            }
        }
    }

    /* Didn't find it */
    return ENODEV;
}

/* Return the number of cores in a socket and the max core ID number */
int PLPA_NAME(get_core_info)(int socket_id, int *num_cores_arg, 
                             int *max_core_id_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == max_core_id_arg || NULL == num_cores_arg) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for some invalid entries */
    if (socket_id < 0 || socket_id > max_socket_id ||
        -1 == max_core_id[socket_id]) {
        return ENOENT;
    }
    ret = num_cores[socket_id];
    if (-1 == ret) {
        return ENOENT;
    }

    /* All done */
    *num_cores_arg = ret;
    *max_core_id_arg = max_core_id[socket_id];
    return 0;
}

/* Given a specific socket, returns the Linux core ID for the Nth core
   (starting with 0) */
int PLPA_NAME(get_core_id)(int socket_id, int core_num, int *core_id)
{
    int ret, i, j, count;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == core_id) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for out of range params */
    if (socket_id < 0 || socket_id > max_socket_id ||
        core_num < 0 || core_num > max_core_id_overall) {
        return EINVAL;
    }

    /* Find the core_num'th core */
    for (count = i = 0, j = socket_id * (max_core_id_overall + 1);
         i <= max_core_id_overall; ++i) {
        if (map_tuple_to_processor_id[j + i]->processor_id >= 0) {
            if (count++ == core_num) {
                *core_id = map_tuple_to_processor_id[j + i]->core_id;
                return 0;
            }
        }
    }

    /* Didn't find it */
    return ENODEV;
}

/* Check to see if a given Linux (socket_id,core_id) tuple exists / is
   online.  Returns 0 on success. */
int PLPA_NAME(get_core_flags)(int socket_id, int core_id,
                              int *exists_arg, int *online_arg)
{
    int ret, i, exists, online;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for bozo arguments */
    if (NULL == exists_arg && NULL == online_arg) {
        return EINVAL;
    }

    /* Check cache behavior */
    if (0 != (ret = cache_action())) {
        return ret;
    }

    /* Check for out of range params */
    if (socket_id < 0 || socket_id > max_socket_id ||
        core_id < 0 || core_id > max_core_id_overall) {
        return EINVAL;
    }

    exists = online = 0;
    i = socket_id * (max_core_id_overall + 1) + core_id;
    if (map_tuple_to_processor_id[i]->processor_id >= 0) {
        exists = 1;
        if (map_tuple_to_processor_id[i]->online) {
            online = 1;
        }
    }

    if (NULL != exists_arg) {
        *exists_arg = exists;
    }
    if (NULL != online_arg) {
        *online_arg = online;
    }
    return 0;
}

/* Set PLPA's caching behavior */
int PLPA_NAME(set_cache_behavior)(PLPA_NAME(cache_behavior_t) behavior)
{
    switch (behavior) {
    case PLPA_NAME_CAPS(CACHE_USE):
        if (PLPA_NAME_CAPS(CACHE_USE) != cache_behavior) {
            load_cache();
            cache_behavior = PLPA_NAME_CAPS(CACHE_USE);
        }
        break;

    case PLPA_NAME_CAPS(CACHE_IGNORE):
        if (PLPA_NAME_CAPS(CACHE_IGNORE) != cache_behavior) {
            clear_cache();
            cache_behavior = PLPA_NAME_CAPS(CACHE_IGNORE);
        }
        break;

    case PLPA_NAME_CAPS(CACHE_REFRESH):
        if (PLPA_NAME_CAPS(CACHE_USE) != cache_behavior) {
            return EINVAL;
        }
        clear_cache();
        load_cache();
        break;

    default:
        return EINVAL;
    }

    return 0;
}