cpufeature.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Contains CPU feature definitions
 *
 * Copyright (C) 2015 ARM Ltd.
 *
 * A note for the weary kernel hacker: the code here is confusing and hard to
 * follow! That's partly because it's solving a nasty problem, but also because
 * there's a little bit of over-abstraction that tends to obscure what's going
 * on behind a maze of helper functions and macros.
 *
 * The basic problem is that hardware folks have started gluing together CPUs
 * with distinct architectural features; in some cases even creating SoCs where
 * user-visible instructions are available only on a subset of the available
 * cores. We try to address this by snapshotting the feature registers of the
 * boot CPU and comparing these with the feature registers of each secondary
 * CPU when bringing them up. If there is a mismatch, then we update the
 * snapshot state to indicate the lowest-common denominator of the feature,
 * known as the "safe" value. This snapshot state can be queried to view the
 * "sanitised" value of a feature register.
 *
 * The sanitised register values are used to decide which capabilities we
 * have in the system. These may be in the form of traditional "hwcaps"
 * advertised to userspace or internal "cpucaps" which are used to configure
 * things like alternative patching and static keys. While a feature mismatch
 * may result in a TAINT_CPU_OUT_OF_SPEC kernel taint, a capability mismatch
 * may prevent a CPU from being onlined at all.
 *
 * Some implementation details worth remembering:
 *
 * - Mismatched features are *always* sanitised to a "safe" value, which
 *   usually indicates that the feature is not supported.
 *
 * - A mismatched feature marked with FTR_STRICT will cause a "SANITY CHECK"
 *   warning when onlining an offending CPU and the kernel will be tainted
 *   with TAINT_CPU_OUT_OF_SPEC.
 *
 * - Features marked as FTR_VISIBLE have their sanitised value visible to
 *   userspace. FTR_VISIBLE features in registers that are only visible
 *   to EL0 by trapping *must* have a corresponding HWCAP so that late
 *   onlining of CPUs cannot lead to features disappearing at runtime.
 *
 * - A "feature" is typically a 4-bit register field. A "capability" is the
 *   high-level description derived from the sanitised field value.
 *
 * - Read the Arm ARM (DDI 0487F.a) section D13.1.3 ("Principles of the ID
 *   scheme for fields in ID registers") to understand when feature fields
 *   may be signed or unsigned (FTR_SIGNED and FTR_UNSIGNED accordingly).
 *
 * - KVM exposes its own view of the feature registers to guest operating
 *   systems regardless of FTR_VISIBLE. This is typically driven from the
 *   sanitised register values to allow virtual CPUs to be migrated between
 *   arbitrary physical CPUs, but some features not present on the host are
 *   also advertised and emulated. Look at sys_reg_descs[] for the gory
 *   details.
 *
 * - If the arm64_ftr_bits[] for a register has a missing field, then this
 *   field is treated as STRICT RES0, including for read_sanitised_ftr_reg().
 *   This is stronger than FTR_HIDDEN and can be used to hide features from
 *   KVM guests.
 */

#define pr_fmt(fmt) "CPU features: " fmt

#include <linux/bsearch.h>
#include <linux/cpumask.h>
#include <linux/crash_dump.h>
#include <linux/sort.h>
#include <linux/stop_machine.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/fpsimd.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/sysreg.h>
#include <asm/traps.h>
#include <asm/virt.h>

/* Kernel representation of AT_HWCAP and AT_HWCAP2 */
static unsigned long elf_hwcap __read_mostly;

#ifdef CONFIG_COMPAT
#define COMPAT_ELF_HWCAP_DEFAULT	\
				(COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\
				 COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
				 COMPAT_HWCAP_TLS|COMPAT_HWCAP_IDIV|\
				 COMPAT_HWCAP_LPAE)
unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT;
unsigned int compat_elf_hwcap2 __read_mostly;
#endif

DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
EXPORT_SYMBOL(cpu_hwcaps);
static struct arm64_cpu_capabilities const __ro_after_init *cpu_hwcaps_ptrs[ARM64_NCAPS];

/* Need also bit for ARM64_CB_PATCH */
DECLARE_BITMAP(boot_capabilities, ARM64_NPATCHABLE);

bool arm64_use_ng_mappings = false;
EXPORT_SYMBOL(arm64_use_ng_mappings);

/*
 * Flag to indicate if we have computed the system wide
 * capabilities based on the boot time active CPUs. This
 * will be used to determine if a new booting CPU should
 * go through the verification process to make sure that it
 * supports the system capabilities, without using a hotplug
 * notifier. This is also used to decide if we could use
 * the fast path for checking constant CPU caps.
 */
DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
EXPORT_SYMBOL(arm64_const_caps_ready);
static inline void finalize_system_capabilities(void)
{
	static_branch_enable(&arm64_const_caps_ready);
}

static int dump_cpu_hwcaps(struct notifier_block *self, unsigned long v, void *p)
{
	/* file-wide pr_fmt adds "CPU features: " prefix */
	pr_emerg("0x%*pb\n", ARM64_NCAPS, &cpu_hwcaps);
	return 0;
}

static struct notifier_block cpu_hwcaps_notifier = {
	.notifier_call = dump_cpu_hwcaps
};

static int __init register_cpu_hwcaps_dumper(void)
{
	atomic_notifier_chain_register(&panic_notifier_list,
				       &cpu_hwcaps_notifier);
	return 0;
}
__initcall(register_cpu_hwcaps_dumper);

DEFINE_STATIC_KEY_ARRAY_FALSE(cpu_hwcap_keys, ARM64_NCAPS);
EXPORT_SYMBOL(cpu_hwcap_keys);

#define __ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
	{						\
		.sign = SIGNED,				\
		.visible = VISIBLE,			\
		.strict = STRICT,			\
		.type = TYPE,				\
		.shift = SHIFT,				\
		.width = WIDTH,				\
		.safe_val = SAFE_VAL,			\
	}

/* Define a feature with unsigned values */
#define ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
	__ARM64_FTR_BITS(FTR_UNSIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)

/* Define a feature with a signed value */
#define S_ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
	__ARM64_FTR_BITS(FTR_SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)

#define ARM64_FTR_END					\
	{						\
		.width = 0,				\
	}

/* meta feature for alternatives */
static bool __maybe_unused
cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);

static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);

static bool __system_matches_cap(unsigned int n);

/*
 * NOTE: Any changes to the visibility of features should be kept in
 * sync with the documentation of the CPU feature register ABI.
 */
static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RNDR_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_FHM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_DP_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM4_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM3_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA3_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RDM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_ATOMICS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_CRC32_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA2_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA1_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_AES_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_I8MM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DGH_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_BF16_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SPECRES_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FRINTTS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPI_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPA_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_API_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_APA_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_DIT_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_AMU_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
				   FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0),
	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI),
	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_FP_SHIFT, 4, ID_AA64PFR0_FP_NI),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSBS_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_F64MM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_F32MM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_I8MM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BF16_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
	/*
	 * We already refuse to boot CPUs that don't support our configured
	 * page size, so we can only detect mismatches for a page size other
	 * than the one we're currently using. Unfortunately, SoCs like this
	 * exist in the wild so, even though we don't like it, we'll have to go
	 * along with it and treat them as non-strict.
	 */
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN16_SHIFT, 4, ID_AA64MMFR0_TGRAN16_NI),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL0_SHIFT, 4, 0),
	/* Linux shouldn't care about secure memory */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_SNSMEM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ASID_SHIFT, 4, 0),
	/*
	 * Differing PARange is fine as long as all peripherals and memory are mapped
	 * within the minimum PARange of all CPUs
	 */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_PARANGE_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_PAN_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_LOR_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HPD_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VHE_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VMIDBITS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HADBS_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_E0PD_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LSM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_UAO_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_CNP_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_ctr[] = {
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DIC_SHIFT, 1, 1),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IDC_SHIFT, 1, 1),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_CWG_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_ERG_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DMINLINE_SHIFT, 4, 1),
	/*
	 * Linux can handle differing I-cache policies. Userspace JITs will
	 * make use of *minLine.
	 * If we have differing I-cache policies, report it as the weakest - VIPT.
	 */
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_EXACT, 14, 2, ICACHE_POLICY_VIPT),	/* L1Ip */
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IMINLINE_SHIFT, 4, 0),
	ARM64_FTR_END,
};

struct arm64_ftr_reg arm64_ftr_reg_ctrel0 = {
	.name		= "SYS_CTR_EL0",
	.ftr_bits	= ftr_ctr
};

static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0xf),	/* InnerShr */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),	/* FCSE */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, 20, 4, 0),	/* AuxReg */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),	/* TCM */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),	/* ShareLvl */
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0xf),	/* OuterShr */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* PMSA */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),	/* VMSA */
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 36, 28, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_PMSVER_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_BRPS_SHIFT, 4, 0),
	/*
	 * We can instantiate multiple PMU instances with different levels
	 * of support.
	 */
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_mvfr2[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* FPMisc */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),		/* SIMDMisc */
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_dczid[] = {
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 4, 1, 1),		/* DZP */
	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),	/* BS */
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_isar0[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DIVIDE_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DEBUG_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_COPROC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_CMPBRANCH_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_BITFIELD_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_BITCOUNT_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_SWAP_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_isar5[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SEVL_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* ac2 */
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_isar4[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SWP_FRAC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_PSR_M_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SYNCH_PRIM_FRAC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_BARRIER_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SMC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_WRITEBACK_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_WITHSHIFTS_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_UNPRIV_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_isar6[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_I8MM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_BF16_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_SPECRES_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_SB_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_FHM_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_DP_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_JSCVT_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_pfr0[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),		/* State3 */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),		/* State2 */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* State1 */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),		/* State0 */
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_pfr1[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_GIC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_VIRT_FRAC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_SEC_FRAC_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_GENTIMER_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_VIRTUALIZATION_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_MPROGMOD_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_SECURITY_SHIFT, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_PROGMOD_SHIFT, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_id_dfr0[] = {
	/* [31:28] TraceFilt */
	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_zcr[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
		ZCR_ELx_LEN_SHIFT, ZCR_ELx_LEN_SIZE, 0),	/* LEN */
	ARM64_FTR_END,
};

/*
 * Common ftr bits for a 32bit register with all hidden, strict
 * attributes, with 4bit feature fields and a default safe value of
 * 0. Covers the following 32bit registers:
 * id_isar[1-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
 */
static const struct arm64_ftr_bits ftr_generic_32bits[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
	ARM64_FTR_END,
};

/* Table for a single 32bit feature value */
static const struct arm64_ftr_bits ftr_single32[] = {
	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 0, 32, 0),
	ARM64_FTR_END,
};

static const struct arm64_ftr_bits ftr_raz[] = {
	ARM64_FTR_END,
};

#define ARM64_FTR_REG(id, table) {		\
	.sys_id = id,				\
	.reg = 	&(struct arm64_ftr_reg){	\
		.name = #id,			\
		.ftr_bits = &((table)[0]),	\
	}}

static const struct __ftr_reg_entry {
	u32			sys_id;
	struct arm64_ftr_reg 	*reg;
} arm64_ftr_regs[] = {

	/* Op1 = 0, CRn = 0, CRm = 1 */
	ARM64_FTR_REG(SYS_ID_PFR0_EL1, ftr_id_pfr0),
	ARM64_FTR_REG(SYS_ID_PFR1_EL1, ftr_id_pfr1),
	ARM64_FTR_REG(SYS_ID_DFR0_EL1, ftr_id_dfr0),
	ARM64_FTR_REG(SYS_ID_MMFR0_EL1, ftr_id_mmfr0),
	ARM64_FTR_REG(SYS_ID_MMFR1_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_ID_MMFR2_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_ID_MMFR3_EL1, ftr_generic_32bits),

	/* Op1 = 0, CRn = 0, CRm = 2 */
	ARM64_FTR_REG(SYS_ID_ISAR0_EL1, ftr_id_isar0),
	ARM64_FTR_REG(SYS_ID_ISAR1_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_ID_ISAR2_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_ID_ISAR3_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_id_isar4),
	ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
	ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
	ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_id_isar6),

	/* Op1 = 0, CRn = 0, CRm = 3 */
	ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),
	ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),

	/* Op1 = 0, CRn = 0, CRm = 4 */
	ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
	ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1),
	ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0),

	/* Op1 = 0, CRn = 0, CRm = 5 */
	ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
	ARM64_FTR_REG(SYS_ID_AA64DFR1_EL1, ftr_raz),

	/* Op1 = 0, CRn = 0, CRm = 6 */
	ARM64_FTR_REG(SYS_ID_AA64ISAR0_EL1, ftr_id_aa64isar0),
	ARM64_FTR_REG(SYS_ID_AA64ISAR1_EL1, ftr_id_aa64isar1),

	/* Op1 = 0, CRn = 0, CRm = 7 */
	ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
	ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
	ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),

	/* Op1 = 0, CRn = 1, CRm = 2 */
	ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr),

	/* Op1 = 3, CRn = 0, CRm = 0 */
	{ SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 },
	ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid),

	/* Op1 = 3, CRn = 14, CRm = 0 */
	ARM64_FTR_REG(SYS_CNTFRQ_EL0, ftr_single32),
};

static int search_cmp_ftr_reg(const void *id, const void *regp)
{
	return (int)(unsigned long)id - (int)((const struct __ftr_reg_entry *)regp)->sys_id;
}

/*
 * get_arm64_ftr_reg - Lookup a feature register entry using its
 * sys_reg() encoding. With the array arm64_ftr_regs sorted in the
 * ascending order of sys_id , we use binary search to find a matching
 * entry.
 *
 * returns - Upon success,  matching ftr_reg entry for id.
 *         - NULL on failure. It is upto the caller to decide
 *	     the impact of a failure.
 */
static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
{
	const struct __ftr_reg_entry *ret;

	ret = bsearch((const void *)(unsigned long)sys_id,
			arm64_ftr_regs,
			ARRAY_SIZE(arm64_ftr_regs),
			sizeof(arm64_ftr_regs[0]),
			search_cmp_ftr_reg);
	if (ret)
		return ret->reg;
	return NULL;
}

static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
			       s64 ftr_val)
{
	u64 mask = arm64_ftr_mask(ftrp);

	reg &= ~mask;
	reg |= (ftr_val << ftrp->shift) & mask;
	return reg;
}

static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
				s64 cur)
{
	s64 ret = 0;

	switch (ftrp->type) {
	case FTR_EXACT:
		ret = ftrp->safe_val;
		break;
	case FTR_LOWER_SAFE:
		ret = new < cur ? new : cur;
		break;
	case FTR_HIGHER_OR_ZERO_SAFE:
		if (!cur || !new)
			break;
		/* Fallthrough */
	case FTR_HIGHER_SAFE:
		ret = new > cur ? new : cur;
		break;
	default:
		BUG();
	}

	return ret;
}

static void __init sort_ftr_regs(void)
{
	int i;

	/* Check that the array is sorted so that we can do the binary search */
	for (i = 1; i < ARRAY_SIZE(arm64_ftr_regs); i++)
		BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
}

/*
 * Initialise the CPU feature register from Boot CPU values.
 * Also initiliases the strict_mask for the register.
 * Any bits that are not covered by an arm64_ftr_bits entry are considered
 * RES0 for the system-wide value, and must strictly match.
 */
static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
{
	u64 val = 0;
	u64 strict_mask = ~0x0ULL;
	u64 user_mask = 0;
	u64 valid_mask = 0;

	const struct arm64_ftr_bits *ftrp;
	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);

	BUG_ON(!reg);

	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
		u64 ftr_mask = arm64_ftr_mask(ftrp);
		s64 ftr_new = arm64_ftr_value(ftrp, new);

		val = arm64_ftr_set_value(ftrp, val, ftr_new);

		valid_mask |= ftr_mask;
		if (!ftrp->strict)
			strict_mask &= ~ftr_mask;
		if (ftrp->visible)
			user_mask |= ftr_mask;
		else
			reg->user_val = arm64_ftr_set_value(ftrp,
							    reg->user_val,
							    ftrp->safe_val);
	}

	val &= valid_mask;

	reg->sys_val = val;
	reg->strict_mask = strict_mask;
	reg->user_mask = user_mask;
}

extern const struct arm64_cpu_capabilities arm64_errata[];
static const struct arm64_cpu_capabilities arm64_features[];

static void __init
init_cpu_hwcaps_indirect_list_from_array(const struct arm64_cpu_capabilities *caps)
{
	for (; caps->matches; caps++) {
		if (WARN(caps->capability >= ARM64_NCAPS,
			"Invalid capability %d\n", caps->capability))
			continue;
		if (WARN(cpu_hwcaps_ptrs[caps->capability],
			"Duplicate entry for capability %d\n",
			caps->capability))
			continue;
		cpu_hwcaps_ptrs[caps->capability] = caps;
	}
}

static void __init init_cpu_hwcaps_indirect_list(void)
{
	init_cpu_hwcaps_indirect_list_from_array(arm64_features);
	init_cpu_hwcaps_indirect_list_from_array(arm64_errata);
}

static void __init setup_boot_cpu_capabilities(void);

void __init init_cpu_features(struct cpuinfo_arm64 *info)
{
	/* Before we start using the tables, make sure it is sorted */
	sort_ftr_regs();

	init_cpu_ftr_reg(SYS_CTR_EL0, info->reg_ctr);
	init_cpu_ftr_reg(SYS_DCZID_EL0, info->reg_dczid);
	init_cpu_ftr_reg(SYS_CNTFRQ_EL0, info->reg_cntfrq);
	init_cpu_ftr_reg(SYS_ID_AA64DFR0_EL1, info->reg_id_aa64dfr0);
	init_cpu_ftr_reg(SYS_ID_AA64DFR1_EL1, info->reg_id_aa64dfr1);
	init_cpu_ftr_reg(SYS_ID_AA64ISAR0_EL1, info->reg_id_aa64isar0);
	init_cpu_ftr_reg(SYS_ID_AA64ISAR1_EL1, info->reg_id_aa64isar1);
	init_cpu_ftr_reg(SYS_ID_AA64MMFR0_EL1, info->reg_id_aa64mmfr0);
	init_cpu_ftr_reg(SYS_ID_AA64MMFR1_EL1, info->reg_id_aa64mmfr1);
	init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
	init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
	init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
	init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);

	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
		init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
		init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
		init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
		init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
		init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
		init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
		init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
		init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
		init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
		init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
		init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
		init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
		init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
		init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
		init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0);
		init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1);
		init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
	}

	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
		init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr);
		sve_init_vq_map();
	}

	/*
	 * Initialize the indirect array of CPU hwcaps capabilities pointers
	 * before we handle the boot CPU below.
	 */
	init_cpu_hwcaps_indirect_list();

	/*
	 * Detect and enable early CPU capabilities based on the boot CPU,
	 * after we have initialised the CPU feature infrastructure.
	 */
	setup_boot_cpu_capabilities();
}

static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
{
	const struct arm64_ftr_bits *ftrp;

	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
		s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val);
		s64 ftr_new = arm64_ftr_value(ftrp, new);

		if (ftr_cur == ftr_new)
			continue;
		/* Find a safe value */
		ftr_new = arm64_ftr_safe_value(ftrp, ftr_new, ftr_cur);
		reg->sys_val = arm64_ftr_set_value(ftrp, reg->sys_val, ftr_new);
	}

}

static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
{
	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);

	BUG_ON(!regp);
	update_cpu_ftr_reg(regp, val);
	if ((boot & regp->strict_mask) == (val & regp->strict_mask))
		return 0;
	pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016llx, CPU%d: %#016llx\n",
			regp->name, boot, cpu, val);
	return 1;
}

static void relax_cpu_ftr_reg(u32 sys_id, int field)
{
	const struct arm64_ftr_bits *ftrp;
	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);

	if (WARN_ON(!regp))
		return;

	for (ftrp = regp->ftr_bits; ftrp->width; ftrp++) {
		if (ftrp->shift == field) {
			regp->strict_mask &= ~arm64_ftr_mask(ftrp);
			break;
		}
	}

	/* Bogus field? */
	WARN_ON(!ftrp->width);
}

static int update_32bit_cpu_features(int cpu, struct cpuinfo_arm64 *info,
				     struct cpuinfo_arm64 *boot)
{
	int taint = 0;
	u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);

	/*
	 * If we don't have AArch32 at all then skip the checks entirely
	 * as the register values may be UNKNOWN and we're not going to be
	 * using them for anything.
	 */
	if (!id_aa64pfr0_32bit_el0(pfr0))
		return taint;

	/*
	 * If we don't have AArch32 at EL1, then relax the strictness of
	 * EL1-dependent register fields to avoid spurious sanity check fails.
	 */
	if (!id_aa64pfr0_32bit_el1(pfr0)) {
		relax_cpu_ftr_reg(SYS_ID_ISAR4_EL1, ID_ISAR4_SMC_SHIFT);
		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_VIRT_FRAC_SHIFT);
		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_SEC_FRAC_SHIFT);
		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_VIRTUALIZATION_SHIFT);
		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_SECURITY_SHIFT);
		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_PROGMOD_SHIFT);
	}

	taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
				      info->reg_id_dfr0, boot->reg_id_dfr0);
	taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
				      info->reg_id_isar0, boot->reg_id_isar0);
	taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
				      info->reg_id_isar1, boot->reg_id_isar1);
	taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
				      info->reg_id_isar2, boot->reg_id_isar2);
	taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
				      info->reg_id_isar3, boot->reg_id_isar3);
	taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
				      info->reg_id_isar4, boot->reg_id_isar4);
	taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
				      info->reg_id_isar5, boot->reg_id_isar5);
	taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
				      info->reg_id_isar6, boot->reg_id_isar6);

	/*
	 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
	 * ACTLR formats could differ across CPUs and therefore would have to
	 * be trapped for virtualization anyway.
	 */
	taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
				      info->reg_id_mmfr0, boot->reg_id_mmfr0);
	taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
				      info->reg_id_mmfr1, boot->reg_id_mmfr1);
	taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
				      info->reg_id_mmfr2, boot->reg_id_mmfr2);
	taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
				      info->reg_id_mmfr3, boot->reg_id_mmfr3);
	taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
				      info->reg_id_pfr0, boot->reg_id_pfr0);
	taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
				      info->reg_id_pfr1, boot->reg_id_pfr1);
	taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
				      info->reg_mvfr0, boot->reg_mvfr0);
	taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
				      info->reg_mvfr1, boot->reg_mvfr1);
	taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
				      info->reg_mvfr2, boot->reg_mvfr2);

	return taint;
}

/*
 * Update system wide CPU feature registers with the values from a
 * non-boot CPU. Also performs SANITY checks to make sure that there
 * aren't any insane variations from that of the boot CPU.
 */
void update_cpu_features(int cpu,
			 struct cpuinfo_arm64 *info,
			 struct cpuinfo_arm64 *boot)
{
	int taint = 0;

	/*
	 * The kernel can handle differing I-cache policies, but otherwise
	 * caches should look identical. Userspace JITs will make use of
	 * *minLine.
	 */
	taint |= check_update_ftr_reg(SYS_CTR_EL0, cpu,
				      info->reg_ctr, boot->reg_ctr);

	/*
	 * Userspace may perform DC ZVA instructions. Mismatched block sizes
	 * could result in too much or too little memory being zeroed if a
	 * process is preempted and migrated between CPUs.
	 */
	taint |= check_update_ftr_reg(SYS_DCZID_EL0, cpu,
				      info->reg_dczid, boot->reg_dczid);

	/* If different, timekeeping will be broken (especially with KVM) */
	taint |= check_update_ftr_reg(SYS_CNTFRQ_EL0, cpu,
				      info->reg_cntfrq, boot->reg_cntfrq);

	/*
	 * The kernel uses self-hosted debug features and expects CPUs to
	 * support identical debug features. We presently need CTX_CMPs, WRPs,
	 * and BRPs to be identical.
	 * ID_AA64DFR1 is currently RES0.
	 */
	taint |= check_update_ftr_reg(SYS_ID_AA64DFR0_EL1, cpu,
				      info->reg_id_aa64dfr0, boot->reg_id_aa64dfr0);
	taint |= check_update_ftr_reg(SYS_ID_AA64DFR1_EL1, cpu,
				      info->reg_id_aa64dfr1, boot->reg_id_aa64dfr1);
	/*
	 * Even in big.LITTLE, processors should be identical instruction-set
	 * wise.
	 */
	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR0_EL1, cpu,
				      info->reg_id_aa64isar0, boot->reg_id_aa64isar0);
	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR1_EL1, cpu,
				      info->reg_id_aa64isar1, boot->reg_id_aa64isar1);

	/*
	 * Differing PARange support is fine as long as all peripherals and
	 * memory are mapped within the minimum PARange of all CPUs.
	 * Linux should not care about secure memory.
	 */
	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR0_EL1, cpu,
				      info->reg_id_aa64mmfr0, boot->reg_id_aa64mmfr0);
	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR1_EL1, cpu,
				      info->reg_id_aa64mmfr1, boot->reg_id_aa64mmfr1);
	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR2_EL1, cpu,
				      info->reg_id_aa64mmfr2, boot->reg_id_aa64mmfr2);

	taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
				      info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
	taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
				      info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);

	taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
				      info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);

	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
		taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
					info->reg_zcr, boot->reg_zcr);

		/* Probe vector lengths, unless we already gave up on SVE */
		if (id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
		    !system_capabilities_finalized())
			sve_update_vq_map();
	}

	/*
	 * This relies on a sanitised view of the AArch64 ID registers
	 * (e.g. SYS_ID_AA64PFR0_EL1), so we call it last.
	 */
	taint |= update_32bit_cpu_features(cpu, info, boot);

	/*
	 * Mismatched CPU features are a recipe for disaster. Don't even
	 * pretend to support them.
	 */
	if (taint) {
		pr_warn_once("Unsupported CPU feature variation detected.\n");
		add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
	}
}

u64 read_sanitised_ftr_reg(u32 id)
{
	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);

	/* We shouldn't get a request for an unsupported register */
	BUG_ON(!regp);
	return regp->sys_val;
}

#define read_sysreg_case(r)	\
	case r:		return read_sysreg_s(r)

/*
 * __read_sysreg_by_encoding() - Used by a STARTING cpu before cpuinfo is populated.
 * Read the system register on the current CPU
 */
static u64 __read_sysreg_by_encoding(u32 sys_id)
{
	switch (sys_id) {
	read_sysreg_case(SYS_ID_PFR0_EL1);
	read_sysreg_case(SYS_ID_PFR1_EL1);
	read_sysreg_case(SYS_ID_DFR0_EL1);
	read_sysreg_case(SYS_ID_MMFR0_EL1);
	read_sysreg_case(SYS_ID_MMFR1_EL1);
	read_sysreg_case(SYS_ID_MMFR2_EL1);
	read_sysreg_case(SYS_ID_MMFR3_EL1);
	read_sysreg_case(SYS_ID_ISAR0_EL1);
	read_sysreg_case(SYS_ID_ISAR1_EL1);
	read_sysreg_case(SYS_ID_ISAR2_EL1);
	read_sysreg_case(SYS_ID_ISAR3_EL1);
	read_sysreg_case(SYS_ID_ISAR4_EL1);
	read_sysreg_case(SYS_ID_ISAR5_EL1);
	read_sysreg_case(SYS_ID_ISAR6_EL1);