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-rw-r--r--Documentation/kernel-parameters.txt2
-rw-r--r--arch/x86/kernel/cpu/common.c18
2 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 86a6746f6833..152ec4e87b57 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2795,6 +2795,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nopat [X86] Disable PAT (page attribute table extension of
pagetables) support.
+ nopcid [X86-64] Disable the PCID cpu feature.
+
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4eece91ada37..81c8a535175d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -163,6 +163,24 @@ static int __init x86_mpx_setup(char *s)
}
__setup("nompx", x86_mpx_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 */