x86/mm: Add the 'nopcid' boot option to turn off PCID

[pandora-kernel.git] / arch / x86 / kernel / cpu / common.c

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e7dd20a..d0619ad 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -155,6 +155,24 @@ static int __init x86_xsaveopt_setup(char *s)
 }
 __setup("noxsaveopt", x86_xsaveopt_setup);
 
+#ifdef CONFIG_X86_64
+static int __init x86_pcid_setup(char *s)
+{
+       /* require an exact match without trailing characters */
+       if (strlen(s))
+               return 0;
+
+       /* do not emit a message if the feature is not present */
+       if (!boot_cpu_has(X86_FEATURE_PCID))
+               return 1;
+
+       setup_clear_cpu_cap(X86_FEATURE_PCID);
+       pr_info("nopcid: PCID feature disabled\n");
+       return 1;
+}
+__setup("nopcid", x86_pcid_setup);
+#endif
+
 static int __init x86_noinvpcid_setup(char *s)
 {
        /* noinvpcid doesn't accept parameters */