cpufeature.c

{

	for (; caps->matches; caps++)
		if (cpus_have_elf_hwcap(caps) && !caps->matches(caps, SCOPE_LOCAL_CPU)) {
			pr_crit("CPU%d: missing HWCAP: %s\n",
					smp_processor_id(), caps->desc);
			cpu_die_early();
		}
}

static void
verify_local_cpu_features(const struct arm64_cpu_capabilities *caps)
{
	for (; caps->matches; caps++) {
		if (!cpus_have_cap(caps->capability))
			continue;
		/*
		 * If the new CPU misses an advertised feature, we cannot proceed
		 * further, park the cpu.
		 */
		if (!caps->matches(caps, SCOPE_LOCAL_CPU)) {
			pr_crit("CPU%d: missing feature: %s\n",
					smp_processor_id(), caps->desc);
			cpu_die_early();
		}
		if (caps->enable)
			caps->enable(NULL);
	}
}

/*
 * Run through the enabled system capabilities and enable() it on this CPU.
 * The capabilities were decided based on the available CPUs at the boot time.
 * Any new CPU should match the system wide status of the capability. If the
 * new CPU doesn't have a capability which the system now has enabled, we
 * cannot do anything to fix it up and could cause unexpected failures. So
 * we park the CPU.
 */
static void verify_local_cpu_capabilities(void)
{
	verify_local_cpu_errata_workarounds();
	verify_local_cpu_features(arm64_features);
	verify_local_elf_hwcaps(arm64_elf_hwcaps);
	if (system_supports_32bit_el0())
		verify_local_elf_hwcaps(compat_elf_hwcaps);
}

void check_local_cpu_capabilities(void)
{
	/*
	 * All secondary CPUs should conform to the early CPU features
	 * in use by the kernel based on boot CPU.
	 */
	check_early_cpu_features();

	/*
	 * If we haven't finalised the system capabilities, this CPU gets
	 * a chance to update the errata work arounds.
	 * Otherwise, this CPU should verify that it has all the system
	 * advertised capabilities.
	 */
	if (!sys_caps_initialised)
		update_cpu_errata_workarounds();
	else
		verify_local_cpu_capabilities();
}

static void __init setup_feature_capabilities(void)
{
	update_cpu_capabilities(arm64_features, "detected feature:");
	enable_cpu_capabilities(arm64_features);
}

/*
 * Check if the current CPU has a given feature capability.
 * Should be called from non-preemptible context.
 */
bool this_cpu_has_cap(unsigned int cap)
{
	const struct arm64_cpu_capabilities *caps;

	if (WARN_ON(preemptible()))
		return false;

	for (caps = arm64_features; caps->desc; caps++)
		if (caps->capability == cap && caps->matches)
			return caps->matches(caps, SCOPE_LOCAL_CPU);

	return false;
}

void __init setup_cpu_features(void)
{
	u32 cwg;
	int cls;

	/* Set the CPU feature capabilies */
	setup_feature_capabilities();
	enable_errata_workarounds();
	setup_elf_hwcaps(arm64_elf_hwcaps);

	if (system_supports_32bit_el0())
		setup_elf_hwcaps(compat_elf_hwcaps);

	/* Advertise that we have computed the system capabilities */
	set_sys_caps_initialised();

	/*
	 * Check for sane CTR_EL0.CWG value.
	 */
	cwg = cache_type_cwg();
	cls = cache_line_size();
	if (!cwg)
		pr_warn("No Cache Writeback Granule information, assuming cache line size %d\n",
			cls);
	if (L1_CACHE_BYTES < cls)
		pr_warn("L1_CACHE_BYTES smaller than the Cache Writeback Granule (%d < %d)\n",
			L1_CACHE_BYTES, cls);
}

static bool __maybe_unused
cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
{
	return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
}