cpufeature.c

/*
 * 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.
 */
void verify_local_cpu_capabilities(void)
{

	check_early_cpu_features();

	/*
	 * If we haven't computed the system capabilities, there is nothing
	 * to verify.
	 */
	if (!sys_caps_initialised)
		return;

	verify_local_cpu_errata();
	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);
}

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_cap(ARM64_HAS_PAN) && !cpus_have_cap(ARM64_HAS_UAO));
}