blacklist.c

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/*
 *   S/390 common I/O routines -- blacklisting of specific devices
 *
 *    Copyright IBM Corp. 1999, 2002
 *    Author(s): Ingo Adlung ([email protected])
 *       Cornelia Huck ([email protected])
 *       Arnd Bergmann ([email protected])
 */

#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/ctype.h>
#include <linux/device.h>

#include <asm/cio.h>
#include <asm/uaccess.h>

#include "blacklist.h"
#include "cio.h"
#include "cio_debug.h"
#include "css.h"
#include "device.h"

/*
 * "Blacklisting" of certain devices:
 * Device numbers given in the commandline as cio_ignore=... won't be known
 * to Linux.
 *
 * These can be single devices or ranges of devices
 */

/* 65536 bits for each set to indicate if a devno is blacklisted or not */
#define __BL_DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
             (8*sizeof(long)))
static unsigned long bl_dev[__MAX_SSID + 1][__BL_DEV_WORDS];
typedef enum {add, free} range_action;

/*
 * Function: blacklist_range
 * (Un-)blacklist the devices from-to
 */
static int blacklist_range(range_action action, unsigned int from_ssid,
               unsigned int to_ssid, unsigned int from,
               unsigned int to, int msgtrigger)
{
    if ((from_ssid > to_ssid) || ((from_ssid == to_ssid) && (from > to))) {
        if (msgtrigger)
            pr_warning("0.%x.%04x to 0.%x.%04x is not a valid "
                   "range for cio_ignore\n", from_ssid, from,
                   to_ssid, to);

        return 1;
    }

    while ((from_ssid < to_ssid) || ((from_ssid == to_ssid) &&
           (from <= to))) {
        if (action == add)
            set_bit(from, bl_dev[from_ssid]);
        else
            clear_bit(from, bl_dev[from_ssid]);
        from++;
        if (from > __MAX_SUBCHANNEL) {
            from_ssid++;
            from = 0;
        }
    }

    return 0;
}

static int pure_hex(char **cp, unsigned int *val, int min_digit,
            int max_digit, int max_val)
{
    int diff;

    diff = 0;
    *val = 0;

    while (diff <= max_digit) {
        int value = hex_to_bin(**cp);

        if (value < 0)
            break;
        *val = *val * 16 + value;
        (*cp)++;
        diff++;
    }

    if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
        return 1;

    return 0;
}

static int parse_busid(char *str, unsigned int *cssid, unsigned int *ssid,
               unsigned int *devno, int msgtrigger)
{
    char *str_work;
    int val, rc, ret;

    rc = 1;

    if (*str == '\0')
        goto out;

    /* old style */
    str_work = str;
    val = simple_strtoul(str, &str_work, 16);

    if (*str_work == '\0') {
        if (val <= __MAX_SUBCHANNEL) {
            *devno = val;
            *ssid = 0;
            *cssid = 0;
            rc = 0;
        }
        goto out;
    }

    /* new style */
    str_work = str;
    ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
    if (ret || (str_work[0] != '.'))
        goto out;
    str_work++;
    ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
    if (ret || (str_work[0] != '.'))
        goto out;
    str_work++;
    ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
    if (ret || (str_work[0] != '\0'))
        goto out;

    rc = 0;
out:
    if (rc && msgtrigger)
        pr_warning("%s is not a valid device for the cio_ignore "
               "kernel parameter\n", str);

    return rc;
}

static int blacklist_parse_parameters(char *str, range_action action,
                      int msgtrigger)
{
    unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
    int rc, totalrc;
    char *parm;
    range_action ra;

    totalrc = 0;

    while ((parm = strsep(&str, ","))) {
        rc = 0;
        ra = action;
        if (*parm == '!') {
            if (ra == add)
                ra = free;
            else
                ra = add;
            parm++;
        }
        if (strcmp(parm, "all") == 0) {
            from_cssid = 0;
            from_ssid = 0;
            from = 0;
            to_cssid = __MAX_CSSID;
            to_ssid = __MAX_SSID;
            to = __MAX_SUBCHANNEL;
        } else {
            rc = parse_busid(strsep(&parm, "-"), &from_cssid,
                     &from_ssid, &from, msgtrigger);
            if (!rc) {
                if (parm != NULL)
                    rc = parse_busid(parm, &to_cssid,
                             &to_ssid, &to,
                             msgtrigger);
                else {
                    to_cssid = from_cssid;
                    to_ssid = from_ssid;
                    to = from;
                }
            }
        }
        if (!rc) {
            rc = blacklist_range(ra, from_ssid, to_ssid, from, to,
                         msgtrigger);
            if (rc)
                totalrc = -EINVAL;
        } else
            totalrc = -EINVAL;
    }

    return totalrc;
}

static int __init
blacklist_setup (char *str)
{
    CIO_MSG_EVENT(6, "Reading blacklist parameters\n");
    if (blacklist_parse_parameters(str, add, 1))
        return 0;
    return 1;
}

__setup ("cio_ignore=", blacklist_setup);

/* Checking if devices are blacklisted */

/*
 * Function: is_blacklisted
 * Returns 1 if the given devicenumber can be found in the blacklist,
 * otherwise 0.
 * Used by validate_subchannel()
 */
int
is_blacklisted (int ssid, int devno)
{
    return test_bit (devno, bl_dev[ssid]);
}

#ifdef CONFIG_PROC_FS
/*
 * Function: blacklist_parse_proc_parameters
 * parse the stuff which is piped to /proc/cio_ignore
 */
static int blacklist_parse_proc_parameters(char *buf)
{
    int rc;
    char *parm;

    parm = strsep(&buf, " ");

    if (strcmp("free", parm) == 0)
        rc = blacklist_parse_parameters(buf, free, 0);
    else if (strcmp("add", parm) == 0)
        rc = blacklist_parse_parameters(buf, add, 0);
    else if (strcmp("purge", parm) == 0)
        return ccw_purge_blacklisted();
    else
        return -EINVAL;

    css_schedule_reprobe();

    return rc;
}

/* Iterator struct for all devices. */
struct ccwdev_iter {
    int devno;
    int ssid;
    int in_range;
};

static void *
cio_ignore_proc_seq_start(struct seq_file *s, loff_t *offset)
{
    struct ccwdev_iter *iter = s->private;

    if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
        return NULL;
    memset(iter, 0, sizeof(*iter));
    iter->ssid = *offset / (__MAX_SUBCHANNEL + 1);
    iter->devno = *offset % (__MAX_SUBCHANNEL + 1);
    return iter;
}

static void
cio_ignore_proc_seq_stop(struct seq_file *s, void *it)
{
}

static void *
cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
{
    struct ccwdev_iter *iter;

    if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
        return NULL;
    iter = it;
    if (iter->devno == __MAX_SUBCHANNEL) {
        iter->devno = 0;
        iter->ssid++;
        if (iter->ssid > __MAX_SSID)
            return NULL;
    } else
        iter->devno++;
    (*offset)++;
    return iter;
}

static int
cio_ignore_proc_seq_show(struct seq_file *s, void *it)
{
    struct ccwdev_iter *iter;

    iter = it;
    if (!is_blacklisted(iter->ssid, iter->devno))
        /* Not blacklisted, nothing to output. */
        return 0;
    if (!iter->in_range) {
        /* First device in range. */
        if ((iter->devno == __MAX_SUBCHANNEL) ||
            !is_blacklisted(iter->ssid, iter->devno + 1))
            /* Singular device. */
            return seq_printf(s, "0.%x.%04x\n",
                      iter->ssid, iter->devno);
        iter->in_range = 1;
        return seq_printf(s, "0.%x.%04x-", iter->ssid, iter->devno);
    }
    if ((iter->devno == __MAX_SUBCHANNEL) ||
        !is_blacklisted(iter->ssid, iter->devno + 1)) {
        /* Last device in range. */
        iter->in_range = 0;
        return seq_printf(s, "0.%x.%04x\n", iter->ssid, iter->devno);
    }
    return 0;
}

static ssize_t
cio_ignore_write(struct file *file, const char __user *user_buf,
         size_t user_len, loff_t *offset)
{
    char *buf;
    ssize_t rc, ret, i;

    if (*offset)
        return -EINVAL;
    if (user_len > 65536)
        user_len = 65536;
    buf = vzalloc(user_len + 1); /* maybe better use the stack? */
    if (buf == NULL)
        return -ENOMEM;

    if (strncpy_from_user (buf, user_buf, user_len) < 0) {
        rc = -EFAULT;
        goto out_free;
    }

    i = user_len - 1;
    while ((i >= 0) && (isspace(buf[i]) || (buf[i] == 0))) {
        buf[i] = '\0';
        i--;
    }
    ret = blacklist_parse_proc_parameters(buf);
    if (ret)
        rc = ret;
    else
        rc = user_len;

out_free:
    vfree (buf);
    return rc;
}

static const struct seq_operations cio_ignore_proc_seq_ops = {
    .start = cio_ignore_proc_seq_start,
    .stop  = cio_ignore_proc_seq_stop,
    .next  = cio_ignore_proc_seq_next,
    .show  = cio_ignore_proc_seq_show,
};

static int
cio_ignore_proc_open(struct inode *inode, struct file *file)
{
    return seq_open_private(file, &cio_ignore_proc_seq_ops,
                sizeof(struct ccwdev_iter));
}

static const struct file_operations cio_ignore_proc_fops = {
    .open    = cio_ignore_proc_open,
    .read    = seq_read,
    .llseek  = seq_lseek,
    .release = seq_release_private,
    .write   = cio_ignore_write,
};

static int
cio_ignore_proc_init (void)
{
    struct proc_dir_entry *entry;

    entry = proc_create("cio_ignore", S_IFREG | S_IRUGO | S_IWUSR, NULL,
                &cio_ignore_proc_fops);
    if (!entry)
        return -ENOENT;
    return 0;
}

__initcall (cio_ignore_proc_init);

#endif /* CONFIG_PROC_FS */