mce_amd_inj.c

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/*
 * A simple MCE injection facility for testing the MCE decoding code. This
 * driver should be built as module so that it can be loaded on production
 * kernels for testing purposes.
 *
 * This file may be distributed under the terms of the GNU General Public
 * License version 2.
 *
 * Copyright (c) 2010:  Borislav Petkov <[email protected]>
 *          Advanced Micro Devices Inc.
 */

#include <linux/kobject.h>
#include <linux/device.h>
#include <linux/edac.h>
#include <linux/module.h>
#include <asm/mce.h>

#include "mce_amd.h"

struct edac_mce_attr {
    struct attribute attr;
    ssize_t (*show) (struct kobject *kobj, struct edac_mce_attr *attr, char *buf);
    ssize_t (*store)(struct kobject *kobj, struct edac_mce_attr *attr,
             const char *buf, size_t count);
};

#define EDAC_MCE_ATTR(_name, _mode, _show, _store)          \
static struct edac_mce_attr mce_attr_##_name = __ATTR(_name, _mode, _show, _store)

static struct kobject *mce_kobj;

/*
 * Collect all the MCi_XXX settings
 */
static struct mce i_mce;

#define MCE_INJECT_STORE(reg)                       \
static ssize_t edac_inject_##reg##_store(struct kobject *kobj,      \
                     struct edac_mce_attr *attr,    \
                     const char *data, size_t count)\
{                                   \
    int ret = 0;                            \
    unsigned long value;                        \
                                    \
    ret = strict_strtoul(data, 16, &value);             \
    if (ret < 0)                            \
        printk(KERN_ERR "Error writing MCE " #reg " field.\n"); \
                                    \
    i_mce.reg = value;                      \
                                    \
    return count;                           \
}

MCE_INJECT_STORE(status);
MCE_INJECT_STORE(misc);
MCE_INJECT_STORE(addr);

#define MCE_INJECT_SHOW(reg)                        \
static ssize_t edac_inject_##reg##_show(struct kobject *kobj,       \
                    struct edac_mce_attr *attr, \
                    char *buf)          \
{                                   \
    return sprintf(buf, "0x%016llx\n", i_mce.reg);          \
}

MCE_INJECT_SHOW(status);
MCE_INJECT_SHOW(misc);
MCE_INJECT_SHOW(addr);

EDAC_MCE_ATTR(status, 0644, edac_inject_status_show, edac_inject_status_store);
EDAC_MCE_ATTR(misc, 0644, edac_inject_misc_show, edac_inject_misc_store);
EDAC_MCE_ATTR(addr, 0644, edac_inject_addr_show, edac_inject_addr_store);

/*
 * This denotes into which bank we're injecting and triggers
 * the injection, at the same time.
 */
static ssize_t edac_inject_bank_store(struct kobject *kobj,
                      struct edac_mce_attr *attr,
                      const char *data, size_t count)
{
    int ret = 0;
    unsigned long value;

    ret = strict_strtoul(data, 10, &value);
    if (ret < 0) {
        printk(KERN_ERR "Invalid bank value!\n");
        return -EINVAL;
    }

    if (value > 5)
        if (boot_cpu_data.x86 != 0x15 || value > 6) {
            printk(KERN_ERR "Non-existent MCE bank: %lu\n", value);
            return -EINVAL;
        }

    i_mce.bank = value;

    amd_decode_mce(NULL, 0, &i_mce);

    return count;
}

static ssize_t edac_inject_bank_show(struct kobject *kobj,
                     struct edac_mce_attr *attr, char *buf)
{
    return sprintf(buf, "%d\n", i_mce.bank);
}

EDAC_MCE_ATTR(bank, 0644, edac_inject_bank_show, edac_inject_bank_store);

static struct edac_mce_attr *sysfs_attrs[] = { &mce_attr_status, &mce_attr_misc,
                           &mce_attr_addr, &mce_attr_bank
};

static int __init edac_init_mce_inject(void)
{
    struct bus_type *edac_subsys = NULL;
    int i, err = 0;

    edac_subsys = edac_get_sysfs_subsys();
    if (!edac_subsys)
        return -EINVAL;

    mce_kobj = kobject_create_and_add("mce", &edac_subsys->dev_root->kobj);
    if (!mce_kobj) {
        printk(KERN_ERR "Error creating a mce kset.\n");
        err = -ENOMEM;
        goto err_mce_kobj;
    }

    for (i = 0; i < ARRAY_SIZE(sysfs_attrs); i++) {
        err = sysfs_create_file(mce_kobj, &sysfs_attrs[i]->attr);
        if (err) {
            printk(KERN_ERR "Error creating %s in sysfs.\n",
                    sysfs_attrs[i]->attr.name);
            goto err_sysfs_create;
        }
    }
    return 0;

err_sysfs_create:
    while (--i >= 0)
        sysfs_remove_file(mce_kobj, &sysfs_attrs[i]->attr);

    kobject_del(mce_kobj);

err_mce_kobj:
    edac_put_sysfs_subsys();

    return err;
}

static void __exit edac_exit_mce_inject(void)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(sysfs_attrs); i++)
        sysfs_remove_file(mce_kobj, &sysfs_attrs[i]->attr);

    kobject_del(mce_kobj);

    edac_put_sysfs_subsys();
}

module_init(edac_init_mce_inject);
module_exit(edac_exit_mce_inject);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Borislav Petkov <[email protected]>");
MODULE_AUTHOR("AMD Inc.");
MODULE_DESCRIPTION("MCE injection facility for testing MCE decoding");