[PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Borislav Petkov]

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.rc2.4.g42e55a5

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