[PATCH 6/8] x86/platform/UV: Verify NMI action is valid, default is standard

Mike Travis
2017-01-13T15:21:17Z

[-- Attachment #1: uv4_add-check-action --]
[-- Type: text/plain, Size: 2989 bytes --]

Verify that the NMI action being set is valid. The default NMI action
changes from the non-standard 'kdb' to the more standard 'dump'.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Alex Thorlton <athorlton@sgi.com>
---
Note: this patch fails checkpatch with the following error:
WARNING: do not add new typedefs
#44: FILE: arch/x86/platform/uv/uv_nmi.c:186:
+typedef char action_t[ACTION_LEN];

But I do not know another way to create the correct parameter for this check:
+#define param_check_action(name, p) __param_check(name, p, action_t)
---
arch/x86/platform/uv/uv_nmi.c | 69 +++++++++++++++++++++++++++++++++++-------
1 file changed, 58 insertions(+), 11 deletions(-)

--- linux.orig/arch/x86/platform/uv/uv_nmi.c
+++ linux/arch/x86/platform/uv/uv_nmi.c
@@ -170,17 +170,64 @@ module_param_named(debug, uv_nmi_debug,
pr_info(fmt, ##__VA_ARGS__); \
} while (0)

-/*
- * Valid NMI Actions:
- * "dump" - dump process stack for each cpu
- * "ips" - dump IP info for each cpu
- * "kdump" - do crash dump
- * "kdb" - enter KDB (default)
- * "kgdb" - enter KGDB
- * "health" - check if CPUs respond to NMI
- */
-static char uv_nmi_action[8] = "kdb";
-module_param_string(action, uv_nmi_action, sizeof(uv_nmi_action), 0644);
+/* Valid NMI Actions */
+#define ACTION_LEN 16
+static struct nmi_action {
+ char *action;
+ char *desc;
+} valid_acts[] = {
+ { "kdump", "do kernel crash dump" },
+ { "dump", "dump process stack for each cpu" },
+ { "ips", "dump Inst Ptr info for each cpu" },
+ { "kdb", "enter KDB (needs kgdboc= assignment)" },
+ { "kgdb", "enter KGDB (needs gdb target remote)" },
+ { "health", "check if CPUs respond to NMI" },
+};
+typedef char action_t[ACTION_LEN];
+static action_t uv_nmi_action = { "dump" };
+
+static int param_get_action(char *buffer, const struct kernel_param *kp)
+{
+ return sprintf(buffer, "%s\n", uv_nmi_action);
+}
+
+static int param_set_action(const char *val, const struct kernel_param *kp)
+{
+ int i;
+ int n = ARRAY_SIZE(valid_acts);
+ char arg[ACTION_LEN], *p;
+
+ /* (remove possible '\n') */
+ strncpy(arg, val, ACTION_LEN - 1);
+ arg[ACTION_LEN - 1] = '\0';
+ p = strchr(arg, '\n');
+ if (p)
+ *p = '\0';
+
+ for (i = 0; i < n; i++)
+ if (!strcmp(arg, valid_acts[i].action))
+ break;
+
+ if (i < n) {
+ strcpy(uv_nmi_action, arg);
+ pr_info("UV: New NMI action:%s\n", uv_nmi_action);
+ return 0;
+ }
+
+ pr_err("UV: Invalid NMI action:%s, valid actions are:\n", arg);
+ for (i = 0; i < n; i++)
+ pr_err("UV: %-8s - %s\n",
+ valid_acts[i].action, valid_acts[i].desc);
+ return -EINVAL;
+}
+
+static const struct kernel_param_ops param_ops_action = {
+ .get = param_get_action,
+ .set = param_set_action,
+};
+#define param_check_action(name, p) __param_check(name, p, action_t)
+
+module_param_named(action, uv_nmi_action, action, 0644);

static inline bool uv_nmi_action_is(const char *action)
{

--