void __init check_bugs(void)
{
	identify_boot_cpu();

	if (!IS_ENABLED(CONFIG_SMP)) {
		pr_info("CPU: ");
		print_cpu_info(&boot_cpu_data);
	}

	/*
	 * Read the SPEC_CTRL MSR to account for reserved bits which may
	 * have unknown values. AMD64_LS_CFG MSR is cached in the early AMD
	 * init code as it is not enumerated and depends on the family.
	 */
	if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
		rdmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);

	/* Allow STIBP in MSR_SPEC_CTRL if supported */
	if (boot_cpu_has(X86_FEATURE_STIBP))
		x86_spec_ctrl_mask |= SPEC_CTRL_STIBP;

	/* Select the proper spectre mitigation before patching alternatives */
	spectre_v2_select_mitigation();

	/*
	 * Select proper mitigation for any exposure to the Speculative Store
	 * Bypass vulnerability.
	 */
	ssb_select_mitigation();

#ifdef CONFIG_X86_32
	/*
	 * Check whether we are able to run this kernel safely on SMP.
	 *
	 * - i386 is no longer supported.
	 * - In order to run on anything without a TSC, we need to be
	 *   compiled for a i486.
	 */
	if (boot_cpu_data.x86 < 4)
		panic("Kernel requires i486+ for 'invlpg' and other features");

	init_utsname()->machine[1] =
		'0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
	alternative_instructions();

	fpu__init_check_bugs();
#else /* CONFIG_X86_64 */
	alternative_instructions();

	/*
	 * Make sure the first 2MB area is not mapped by huge pages
	 * There are typically fixed size MTRRs in there and overlapping
	 * MTRRs into large pages causes slow downs.
	 *
	 * Right now we don't do that with gbpages because there seems
	 * very little benefit for that case.
	 */
	if (!direct_gbpages)
		set_memory_4k((unsigned long)__va(0), 1);
#endif
}

Unknown