Warning: use of this parameter will taint the kernel
and may cause unknown problems.
+ fred= [X86-64]
+ Enable/disable Flexible Return and Event Delivery.
+ Format: { on | off }
+ on: enable FRED when it's present.
+ off: disable FRED, the default setting.
+
ftrace=[tracer]
[FTRACE] will set and start the specified tracer
as early as possible in order to facilitate early
}
#endif
+/* Do not enable FRED by default yet. */
+static bool enable_fred __ro_after_init = false;
+
+#ifdef CONFIG_X86_FRED
+static int __init fred_setup(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (!cpu_feature_enabled(X86_FEATURE_FRED))
+ return 0;
+
+ if (!strcmp(str, "on"))
+ enable_fred = true;
+ else if (!strcmp(str, "off"))
+ enable_fred = false;
+ else
+ pr_warn("invalid FRED option: 'fred=%s'\n", str);
+ return 0;
+}
+early_param("fred", fred_setup);
+#endif
+
void __init trap_init(void)
{
+ if (cpu_feature_enabled(X86_FEATURE_FRED) && !enable_fred)
+ setup_clear_cpu_cap(X86_FEATURE_FRED);
+
/* Init cpu_entry_area before IST entries are set up */
setup_cpu_entry_areas();