linux-kernel - [PATCH] RAS/CEC: Add debugfs switch to disable at run time

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Date:   Thu, 18 Apr 2019 15:02:29 -0700
From:   Tony Luck <tony.luck@...el.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Tony Luck <tony.luck@...el.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] RAS/CEC: Add debugfs switch to disable at run time

Useful when running error injection tests that want to
see all of the MCi_(STATUS|ADDR|MISC) data via /dev/mcelog.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 drivers/ras/cec.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 2d9ec378a8bc..a2ceedcd8516 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -123,6 +123,9 @@ static u64 dfs_pfn;
 /* Amount of errors after which we offline */
 static unsigned int count_threshold = COUNT_MASK;
 
+/* debugfs switch to enable/disable CEC */
+static u64 cec_enabled = 1;
+
 /*
  * The timer "decays" element count each timer_interval which is 24hrs by
  * default.
@@ -400,6 +403,14 @@ static int count_threshold_set(void *data, u64 val)
 }
 DEFINE_DEBUGFS_ATTRIBUTE(count_threshold_ops, u64_get, count_threshold_set, "%lld\n");
 
+static int enable_set(void *data, u64 val)
+{
+	ce_arr.disabled = !val;
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(enable_ops, u64_get, enable_set, "%lld\n");
+
 static int array_dump(struct seq_file *m, void *v)
 {
 	struct ce_array *ca = &ce_arr;
@@ -451,7 +462,7 @@ static const struct file_operations array_ops = {
 
 static int __init create_debugfs_nodes(void)
 {
-	struct dentry *d, *pfn, *decay, *count, *array;
+	struct dentry *d, *pfn, *decay, *count, *array, *enable;
 
 	d = debugfs_create_dir("cec", ras_debugfs_dir);
 	if (!d) {
@@ -485,6 +496,13 @@ static int __init create_debugfs_nodes(void)
 		goto err;
 	}
 
+	enable = debugfs_create_file("enable", S_IRUSR | S_IWUSR, d,
+				    &cec_enabled, &enable_ops);
+	if (!enable) {
+		pr_warn("Error creating enable debugfs node!\n");
+		goto err;
+	}
+
 
 	return 0;
 
-- 
2.19.1