diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 138f6664b2e29fe4ca71225fde00ac2ea695a941..b0fa5273b0fca63b494e687437080ae64e5f4b88 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2857,6 +2857,9 @@
 	no5lvl		[X86-64] Disable 5-level paging mode. Forces
 			kernel to use 4-level paging instead.
 
+	unsafe_fsgsbase	[X86] Allow FSGSBASE instructions.  This will be
+			replaced with a nofsgsbase flag.
+
 	no_console_suspend
 			[HW] Never suspend the console
 			Disable suspending of consoles during suspend and
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index dad20bc891d500a22af3f447e49da9119630bbf8..71defe2d1b7c01dec1b34a3a6dbb6c597f8f662a 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -366,6 +366,22 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c)
 	cr4_clear_bits(X86_CR4_UMIP);
 }
 
+/*
+ * Temporary hack: FSGSBASE is unsafe until a few kernel code paths are
+ * updated. This allows us to get the kernel ready incrementally.
+ *
+ * Once all the pieces are in place, these will go away and be replaced with
+ * a nofsgsbase chicken flag.
+ */
+static bool unsafe_fsgsbase;
+
+static __init int setup_unsafe_fsgsbase(char *arg)
+{
+	unsafe_fsgsbase = true;
+	return 1;
+}
+__setup("unsafe_fsgsbase", setup_unsafe_fsgsbase);
+
 /*
  * Protection Keys are not available in 32-bit mode.
  */
@@ -1370,6 +1386,14 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 	setup_smap(c);
 	setup_umip(c);
 
+	/* Enable FSGSBASE instructions if available. */
+	if (cpu_has(c, X86_FEATURE_FSGSBASE)) {
+		if (unsafe_fsgsbase)
+			cr4_set_bits(X86_CR4_FSGSBASE);
+		else
+			clear_cpu_cap(c, X86_FEATURE_FSGSBASE);
+	}
+
 	/*
 	 * The vendor-specific functions might have changed features.
 	 * Now we do "generic changes."