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    Subject[PATCH 6/9] x86, RAS: Convert mce-inject module to debugfs
    Date
    From: Borislav Petkov <borislav.petkov@amd.com>

    This is a module which is used for debugging MCE decoding paths so its
    userspace interface should go to debugfs, where it belongs conceptually.

    While at it, add a warning to the Kconfig text that this interface is
    unstable and no userspace scripts should rely all too much on it.

    Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
    ---
    arch/x86/kernel/cpu/ras/Kconfig | 12 +-
    arch/x86/kernel/cpu/ras/amd/mce-inject.c | 181 +++++++++++++-----------------
    2 files changed, 86 insertions(+), 107 deletions(-)

    diff --git a/arch/x86/kernel/cpu/ras/Kconfig b/arch/x86/kernel/cpu/ras/Kconfig
    index 39dd0af..46d375f 100644
    --- a/arch/x86/kernel/cpu/ras/Kconfig
    +++ b/arch/x86/kernel/cpu/ras/Kconfig
    @@ -23,11 +23,13 @@ config X86_AMD_DECODE_MCE
    has been initialized.

    config X86_AMD_MCE_INJECT
    - tristate "Simple MCE injection interface over /sysfs"
    - depends on X86_AMD_DECODE_MCE
    + tristate "Inject MCEs"
    + depends on X86_AMD_DECODE_MCE && DEBUG_FS
    default n
    - help
    - This is a simple interface to inject MCEs over /sysfs and test
    - the MCE decoding code.
    + ---help---
    + This is a simple debugfs interface to inject MCEs and test different
    + aspects of the MCE handling code.
    +
    + WARNING: Do not even assume that this interface is staying stable!

    endmenu
    diff --git a/arch/x86/kernel/cpu/ras/amd/mce-inject.c b/arch/x86/kernel/cpu/ras/amd/mce-inject.c
    index a38806a..fdec361 100644
    --- a/arch/x86/kernel/cpu/ras/amd/mce-inject.c
    +++ b/arch/x86/kernel/cpu/ras/amd/mce-inject.c
    @@ -1,171 +1,148 @@
    /*
    - * 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.
    + * A simple MCE injection facility for testing different aspects of the RAS
    + * 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 <borislav.petkov@amd.com>
    - * Advanced Micro Devices Inc.
    + * Copyright (c) 2010-11: Borislav Petkov <borislav.petkov@amd.com>
    + * Advanced Micro Devices Inc.
    */

    #include <linux/kobject.h>
    #include <linux/sysdev.h>
    -#include <linux/edac.h>
    +#include <linux/debugfs.h>
    #include <asm/mce.h>
    #include <ras/amd/mce-decode.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;
    +static struct dentry *dfs_inj;

    -#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)\
    +#define MCE_INJECT_SET(reg) \
    +static int inj_##reg##_set(void *data, u64 val) \
    { \
    - int ret = 0; \
    - unsigned long value; \
    - \
    - ret = strict_strtoul(data, 16, &value); \
    - if (ret < 0) \
    - printk(KERN_ERR "Error writing MCE " #reg " field.\n"); \
    + struct mce *m = (struct mce *)data; \
    \
    - i_mce.reg = value; \
    - \
    - return count; \
    + m->reg = val; \
    + return 0; \
    }

    -MCE_INJECT_STORE(status);
    -MCE_INJECT_STORE(misc);
    -MCE_INJECT_STORE(addr);
    +MCE_INJECT_SET(status);
    +MCE_INJECT_SET(misc);
    +MCE_INJECT_SET(addr);

    -#define MCE_INJECT_SHOW(reg) \
    -static ssize_t edac_inject_##reg##_show(struct kobject *kobj, \
    - struct edac_mce_attr *attr, \
    - char *buf) \
    +#define MCE_INJECT_GET(reg) \
    +static int inj_##reg##_get(void *data, u64 *val) \
    { \
    - return sprintf(buf, "0x%016llx\n", i_mce.reg); \
    + struct mce *m = (struct mce *)data; \
    + \
    + *val = m->reg; \
    + return 0; \
    }

    -MCE_INJECT_SHOW(status);
    -MCE_INJECT_SHOW(misc);
    -MCE_INJECT_SHOW(addr);
    +MCE_INJECT_GET(status);
    +MCE_INJECT_GET(misc);
    +MCE_INJECT_GET(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);
    +DEFINE_SIMPLE_ATTRIBUTE(status_fops, inj_status_get, inj_status_set, "%llx\n");
    +DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
    +DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");

    /*
    * 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)
    +static int inj_bank_set(void *data, u64 val)
    {
    - int ret = 0;
    - unsigned long value;
    -
    - ret = strict_strtoul(data, 10, &value);
    - if (ret < 0) {
    - printk(KERN_ERR "Invalid bank value!\n");
    - return -EINVAL;
    - }
    + struct mce *m = (struct mce *)data;

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

    - i_mce.bank = value;
    + m->bank = val;

    - amd_decode_mce(NULL, 0, &i_mce);
    + amd_decode_mce(NULL, 0, m);

    - return count;
    + return 0;
    }

    -static ssize_t edac_inject_bank_show(struct kobject *kobj,
    - struct edac_mce_attr *attr, char *buf)
    +static int inj_bank_get(void *data, u64 *val)
    {
    - return sprintf(buf, "%d\n", i_mce.bank);
    -}
    + struct mce *m = (struct mce *)data;

    -EDAC_MCE_ATTR(bank, 0644, edac_inject_bank_show, edac_inject_bank_store);
    + *val = m->bank;
    + return 0;
    +}

    -static struct edac_mce_attr *sysfs_attrs[] = { &mce_attr_status, &mce_attr_misc,
    - &mce_attr_addr, &mce_attr_bank
    +DEFINE_SIMPLE_ATTRIBUTE(bank_fops, inj_bank_get, inj_bank_set, "%llu\n");
    +
    +struct dfs_node {
    + char *name;
    + struct dentry *d;
    + const struct file_operations *fops;
    +} dfs_fls[] = {
    + { .name = "status", .fops = &status_fops },
    + { .name = "misc", .fops = &misc_fops },
    + { .name = "addr", .fops = &addr_fops },
    + { .name = "bank", .fops = &bank_fops },
    };

    -static int __init edac_init_mce_inject(void)
    +static int __init init_mce_inject(void)
    {
    - struct sysdev_class *edac_class = NULL;
    - int i, err = 0;
    + int i;

    - edac_class = edac_get_sysfs_class();
    - if (!edac_class)
    + dfs_inj = debugfs_create_dir("mce-inject", NULL);
    + if (!dfs_inj)
    return -EINVAL;

    - mce_kobj = kobject_create_and_add("mce", &edac_class->kset.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(dfs_fls); i++) {
    + dfs_fls[i].d = debugfs_create_file(dfs_fls[i].name,
    + S_IRUSR | S_IWUSR,
    + dfs_inj,
    + &i_mce,
    + dfs_fls[i].fops);
    +
    + if (!dfs_fls[i].d)
    + goto err_dfs_add;

    - 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:
    +err_dfs_add:
    while (--i >= 0)
    - sysfs_remove_file(mce_kobj, &sysfs_attrs[i]->attr);
    -
    - kobject_del(mce_kobj);
    + debugfs_remove(dfs_fls[i].d);

    -err_mce_kobj:
    - edac_put_sysfs_class();
    + debugfs_remove(dfs_inj);
    + dfs_inj = NULL;

    - return err;
    + return -ENOMEM;
    }

    -static void __exit edac_exit_mce_inject(void)
    +static void __exit exit_mce_inject(void)
    {
    int i;

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

    - kobject_del(mce_kobj);
    + memset(&dfs_fls, 0, sizeof(dfs_fls));

    - edac_put_sysfs_class();
    + debugfs_remove(dfs_inj);
    + dfs_inj = NULL;
    }

    -module_init(edac_init_mce_inject);
    -module_exit(edac_exit_mce_inject);
    +module_init(init_mce_inject);
    +module_exit(exit_mce_inject);

    MODULE_LICENSE("GPL");
    MODULE_AUTHOR("Borislav Petkov <borislav.petkov@amd.com>");
    MODULE_AUTHOR("AMD Inc.");
    -MODULE_DESCRIPTION("MCE injection facility for testing MCE decoding");
    +MODULE_DESCRIPTION("MCE injection facility for RAS testing");
    --
    1.7.4.rc2


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