x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit

	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.

	nofsgsbase	[X86] Disables FSGSBASE instructions.

	no_console_suspend

			[HW] Never suspend the console

	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)

static __init int x86_nofsgsbase_setup(char *arg)

{

	unsafe_fsgsbase = true;

	/* Require an exact match without trailing characters. */

	if (strlen(arg))

		return 0;

	/* Do not emit a message if the feature is not present. */

	if (!boot_cpu_has(X86_FEATURE_FSGSBASE))

		return 1;

	setup_clear_cpu_cap(X86_FEATURE_FSGSBASE);

	pr_info("FSGSBASE disabled via kernel command line\n");

	return 1;

}

__setup("unsafe_fsgsbase", setup_unsafe_fsgsbase);

__setup("nofsgsbase", x86_nofsgsbase_setup);

/*

 * Protection Keys are not available in 32-bit mode.

	setup_umip(c);

	/* Enable FSGSBASE instructions if available. */

	if (cpu_has(c, X86_FEATURE_FSGSBASE)) {

		if (unsafe_fsgsbase)

	if (cpu_has(c, X86_FEATURE_FSGSBASE))

		cr4_set_bits(X86_CR4_FSGSBASE);

		else

			clear_cpu_cap(c, X86_FEATURE_FSGSBASE);

	}

	/*

	 * The vendor-specific functions might have changed features.