EDAC: Boundary-check edac_debug_level

Only levels [0:4] are allowed so enforce that. Also, while at it,
massage Kconfig text and add valid debug levels range to the module
parameter description.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

2 files changed, 24 insertions, 11 deletions

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 409b92b8d346..bb82d6be793c 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -42,10 +42,10 @@ config EDAC_LEGACY_SYSFS
 config EDAC_DEBUG
         bool "Debugging"
         help
-          This turns on debugging information for the entire EDAC
-          sub-system. You can insert module with "debug_level=x", current
-          there're four debug levels (x=0,1,2,3 from low to high).
-          Usually you should select 'N'.
+          This turns on debugging information for the entire EDAC subsystem.
+          You do so by inserting edac_module with "edac_debug_level=x." Valid
+          levels are 0-4 (from low to high) and by default it is set to 2.
+          Usually you should select 'N' here.
 
 config EDAC_DECODE_MCE
         tristate "Decode MCEs in human-readable form (only on AMD for now)"
diff --git a/drivers/edac/edac_module.c b/drivers/edac/edac_module.c
index 58a28d838f37..12c951a2c33d 100644
--- a/drivers/edac/edac_module.c
+++ b/drivers/edac/edac_module.c
@@ -18,9 +18,29 @@
 #define EDAC_VERSION "Ver: 3.0.0"
 
 #ifdef CONFIG_EDAC_DEBUG
+
+static int edac_set_debug_level(const char *buf, struct kernel_param *kp)
+{
+        unsigned long val;
+        int ret;
+
+        ret = kstrtoul(buf, 0, &val);
+        if (ret)
+                return ret;
+
+        if (val < 0 || val > 4)
+                return -EINVAL;
+
+        return param_set_int(buf, kp);
+}
+
 /* Values of 0 to 4 will generate output */
 int edac_debug_level = 2;
 EXPORT_SYMBOL_GPL(edac_debug_level);
+
+module_param_call(edac_debug_level, edac_set_debug_level, param_get_int,
+                  &edac_debug_level, 0644);
+MODULE_PARM_DESC(edac_debug_level, "EDAC debug level: [0-4], default: 2");
 #endif
 
 /* scope is to module level only */
@@ -132,10 +152,3 @@ module_exit(edac_exit);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Doug Thompson www.softwarebitmaker.com, et al");
 MODULE_DESCRIPTION("Core library routines for EDAC reporting");
-
-/* refer to *_sysfs.c files for parameters that are exported via sysfs */
-
-#ifdef CONFIG_EDAC_DEBUG
-module_param(edac_debug_level, int, 0644);
-MODULE_PARM_DESC(edac_debug_level, "Debug level");
-#endif