[PATCH 3/6] x86, RAS: Convert mce-inject module to debugfs

From: Borislav Petkov
Date: Mon Oct 08 2012 - 13:12:45 EST


From: Borislav Petkov <borislav.petkov@xxxxxxx>

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@xxxxxxx>
---
arch/x86/ras/Kconfig | 11 ++-
arch/x86/ras/amd/mce-inject.c | 182 ++++++++++++++++++------------------------
2 files changed, 86 insertions(+), 107 deletions(-)

diff --git a/arch/x86/ras/Kconfig b/arch/x86/ras/Kconfig
index 9362f54bfe0f..4334ab92b3b0 100644
--- a/arch/x86/ras/Kconfig
+++ b/arch/x86/ras/Kconfig
@@ -2,10 +2,13 @@ menu "AMD RAS features"
depends on X86_RAS && CPU_SUP_AMD

config X86_AMD_MCE_INJECT
- tristate "Simple MCE injection interface over /sysfs"
+ tristate "Inject MCEs"
+ depends on 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/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
index 90aa317b09a6..66969eab5591 100644
--- a/arch/x86/ras/amd/mce-inject.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -1,173 +1,149 @@
/*
- * 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@xxxxxxx>
- * Advanced Micro Devices Inc.
+ * Copyright (c) 2010-12: Borislav Petkov <borislav.petkov@xxxxxxx>
+ * Advanced Micro Devices Inc.
*/

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

#include "../../../drivers/edac/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;
+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"); \
- \
- i_mce.reg = value; \
+ struct mce *m = (struct mce *)data; \
\
- 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;
+ struct mce *m = (struct mce *)data;

- 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);
+ if (val > 5) {
+ if (boot_cpu_data.x86 != 0x15 || val > 6) {
+ pr_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 bus_type *edac_subsys = NULL;
- int i, err = 0;
+ int i;

- edac_subsys = edac_get_sysfs_subsys();
- if (!edac_subsys)
+ dfs_inj = debugfs_create_dir("mce-inject", NULL);
+ if (!dfs_inj)
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(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);

- 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;
- }
+ if (!dfs_fls[i].d)
+ goto err_dfs_add;
}
+
return 0;

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

- kobject_del(mce_kobj);
+ debugfs_remove(dfs_inj);
+ dfs_inj = NULL;

-err_mce_kobj:
- edac_put_sysfs_subsys();
-
- 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_subsys();
+ 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@xxxxxxx>");
MODULE_AUTHOR("AMD Inc.");
-MODULE_DESCRIPTION("MCE injection facility for testing MCE decoding");
+MODULE_DESCRIPTION("MCE injection facility for RAS testing");
--
1.8.0.rc0.18.gf84667d

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