arm64: cpufeature: Fix the type of no FP/SIMD capability

[mirror_ubuntu-bionic-kernel.git] / arch / arm64 / kernel / cpufeature.c

/*
 * Contains CPU feature definitions
 *
 * Copyright (C) 2015 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

#include <linux/bsearch.h>
#include <linux/cpumask.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>

unsigned long elf_hwcap __read_mostly;
EXPORT_SYMBOL_GPL(elf_hwcap);

#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_VFP|\
                                 COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
                                 COMPAT_HWCAP_NEON|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);

/*
 * 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.
 */
static bool sys_caps_initialised;

static inline void set_sys_caps_initialised(void)
{
        sys_caps_initialised = true;
}

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);


/*
 * 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_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_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, 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_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),
        /* Linux doesn't care about the EL3 */
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, 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_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_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_STRICT, 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, 29, 1, 1),      /* DIC */
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 28, 1, 1),      /* IDC */
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, 24, 4, 0),     /* CWG */
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, 20, 4, 0),     /* ERG */
        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_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_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_dfr0[] = {
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
        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[0-4], 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_generic_32bits),
        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_generic_32bits),
        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_generic_32bits),
        ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
        ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),

        /* 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_raz),

        /* 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 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_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();
        }

        /*
         * 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;
}

/*
 * 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);

        /*
         * EL3 is not our concern.
         */
        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 we have AArch32, we care about 32-bit features for compat.
         * If the system doesn't support AArch32, don't update them.
         */
        if (id_aa64pfr0_32bit_el0(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
                id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {

                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);

                /*
                 * 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);
        }

        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)) &&
                    !sys_caps_initialised)
                        sve_update_vq_map();
        }

        /*
         * 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_MVFR0_EL1);
        read_sysreg_case(SYS_MVFR1_EL1);
        read_sysreg_case(SYS_MVFR2_EL1);

        read_sysreg_case(SYS_ID_AA64PFR0_EL1);
        read_sysreg_case(SYS_ID_AA64PFR1_EL1);
        read_sysreg_case(SYS_ID_AA64DFR0_EL1);
        read_sysreg_case(SYS_ID_AA64DFR1_EL1);
        read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
        read_sysreg_case(SYS_ID_AA64MMFR1_EL1);
        read_sysreg_case(SYS_ID_AA64MMFR2_EL1);
        read_sysreg_case(SYS_ID_AA64ISAR0_EL1);
        read_sysreg_case(SYS_ID_AA64ISAR1_EL1);

        read_sysreg_case(SYS_CNTFRQ_EL0);
        read_sysreg_case(SYS_CTR_EL0);
        read_sysreg_case(SYS_DCZID_EL0);

        default:
                BUG();
                return 0;
        }
}

#include <linux/irqchip/arm-gic-v3.h>

static bool
feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
{
        int val = cpuid_feature_extract_field(reg, entry->field_pos, entry->sign);

        return val >= entry->min_field_value;
}

static bool
has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope)
{
        u64 val;

        WARN_ON(scope == SCOPE_LOCAL_CPU && preemptible());
        if (scope == SCOPE_SYSTEM)
                val = read_sanitised_ftr_reg(entry->sys_reg);
        else
                val = __read_sysreg_by_encoding(entry->sys_reg);

        return feature_matches(val, entry);
}

static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope)
{
        bool has_sre;

        if (!has_cpuid_feature(entry, scope))
                return false;

        has_sre = gic_enable_sre();
        if (!has_sre)
                pr_warn_once("%s present but disabled by higher exception level\n",
                             entry->desc);

        return has_sre;
}

static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
{
        u32 midr = read_cpuid_id();

        /* Cavium ThunderX pass 1.x and 2.x */
        return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX,
                MIDR_CPU_VAR_REV(0, 0),
                MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
}

static bool hyp_offset_low(const struct arm64_cpu_capabilities *entry,
                           int __unused)
{
        phys_addr_t idmap_addr = __pa_symbol(__hyp_idmap_text_start);

        /*
         * Activate the lower HYP offset only if:
         * - the idmap doesn't clash with it,
         * - the kernel is not running at EL2.
         */
        return idmap_addr > GENMASK(VA_BITS - 2, 0) && !is_kernel_in_hyp_mode();
}

static bool has_no_fpsimd(const struct arm64_cpu_capabilities *entry, int __unused)
{
        u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);

        return cpuid_feature_extract_signed_field(pfr0,
                                        ID_AA64PFR0_FP_SHIFT) < 0;
}

static bool __meltdown_safe = true;
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */

static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
                                int scope)
{
        /* List of CPUs that are not vulnerable and don't need KPTI */
        static const struct midr_range kpti_safe_list[] = {
                MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
                MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A35),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A53),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
                MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
                { /* sentinel */ }
        };
        char const *str = "kpti command line option";
        bool meltdown_safe;

        meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);

        /* Defer to CPU feature registers */
        if (has_cpuid_feature(entry, scope))
                meltdown_safe = true;

        if (!meltdown_safe)
                __meltdown_safe = false;

        /*
         * For reasons that aren't entirely clear, enabling KPTI on Cavium
         * ThunderX leads to apparent I-cache corruption of kernel text, which
         * ends as well as you might imagine. Don't even try.
         */
        if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456)) {
                str = "ARM64_WORKAROUND_CAVIUM_27456";
                __kpti_forced = -1;
        }

        /* Useful for KASLR robustness */
        if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) {
                if (!__kpti_forced) {
                        str = "KASLR";
                        __kpti_forced = 1;
                }
        }

        if (cpu_mitigations_off() && !__kpti_forced) {
                str = "mitigations=off";
                __kpti_forced = -1;
        }

        if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
                pr_info_once("kernel page table isolation disabled by kernel configuration\n");
                return false;
        }

        /* Forced? */
        if (__kpti_forced) {
                pr_info_once("kernel page table isolation forced %s by %s\n",
                             __kpti_forced > 0 ? "ON" : "OFF", str);
                return __kpti_forced > 0;
        }

        return !meltdown_safe;
}

#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static void
kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
{
        typedef void (kpti_remap_fn)(int, int, phys_addr_t);
        extern kpti_remap_fn idmap_kpti_install_ng_mappings;
        kpti_remap_fn *remap_fn;

        static bool kpti_applied = false;
        int cpu = smp_processor_id();

        if (kpti_applied)
                return;

        remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);

        cpu_install_idmap();
        remap_fn(cpu, num_online_cpus(), __pa_symbol(swapper_pg_dir));
        cpu_uninstall_idmap();

        if (!cpu)
                kpti_applied = true;

        return;
}
#else
static void
kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
{
}
#endif  /* CONFIG_UNMAP_KERNEL_AT_EL0 */

static int __init parse_kpti(char *str)
{
        bool enabled;
        int ret = strtobool(str, &enabled);

        if (ret)
                return ret;

        __kpti_forced = enabled ? 1 : -1;
        return 0;
}
early_param("kpti", parse_kpti);

#ifdef CONFIG_ARM64_VHE
static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)
{
        return is_kernel_in_hyp_mode();
}

static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
{
        /*
         * Copy register values that aren't redirected by hardware.
         *
         * Before code patching, we only set tpidr_el1, all CPUs need to copy
         * this value to tpidr_el2 before we patch the code. Once we've done
         * that, freshly-onlined CPUs will set tpidr_el2, so we don't need to
         * do anything here.
         */
        if (!alternatives_applied)
                write_sysreg(read_sysreg(tpidr_el1), tpidr_el2);
}
#endif

#ifdef CONFIG_ARM64_SSBD
static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr)
{
        if (user_mode(regs))
                return 1;

        if (instr & BIT(CRm_shift))
                regs->pstate |= PSR_SSBS_BIT;
        else
                regs->pstate &= ~PSR_SSBS_BIT;

        arm64_skip_faulting_instruction(regs, 4);
        return 0;
}

static struct undef_hook ssbs_emulation_hook = {
        .instr_mask     = ~(1U << CRm_shift),
        .instr_val      = 0xd500001f | REG_PSTATE_SSBS_IMM,
        .fn             = ssbs_emulation_handler,
};

static void cpu_enable_ssbs(const struct arm64_cpu_capabilities *__unused)
{
        static bool undef_hook_registered = false;
        static DEFINE_SPINLOCK(hook_lock);

        spin_lock(&hook_lock);
        if (!undef_hook_registered) {
                register_undef_hook(&ssbs_emulation_hook);
                undef_hook_registered = true;
        }
        spin_unlock(&hook_lock);

        if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
                sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS);
                arm64_set_ssbd_mitigation(false);
        } else {
                arm64_set_ssbd_mitigation(true);
        }
}
#endif /* CONFIG_ARM64_SSBD */

static const struct arm64_cpu_capabilities arm64_features[] = {
        {
                .desc = "GIC system register CPU interface",
                .capability = ARM64_HAS_SYSREG_GIC_CPUIF,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_useable_gicv3_cpuif,
                .sys_reg = SYS_ID_AA64PFR0_EL1,
                .field_pos = ID_AA64PFR0_GIC_SHIFT,
                .sign = FTR_UNSIGNED,
                .min_field_value = 1,
        },
#ifdef CONFIG_ARM64_PAN
        {
                .desc = "Privileged Access Never",
                .capability = ARM64_HAS_PAN,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64MMFR1_EL1,
                .field_pos = ID_AA64MMFR1_PAN_SHIFT,
                .sign = FTR_UNSIGNED,
                .min_field_value = 1,
                .cpu_enable = cpu_enable_pan,
        },
#endif /* CONFIG_ARM64_PAN */
#if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
        {
                .desc = "LSE atomic instructions",
                .capability = ARM64_HAS_LSE_ATOMICS,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64ISAR0_EL1,
                .field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
                .sign = FTR_UNSIGNED,
                .min_field_value = 2,
        },
#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
        {
                .desc = "Software prefetching using PRFM",
                .capability = ARM64_HAS_NO_HW_PREFETCH,
                .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
                .matches = has_no_hw_prefetch,
        },
#ifdef CONFIG_ARM64_UAO
        {
                .desc = "User Access Override",
                .capability = ARM64_HAS_UAO,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64MMFR2_EL1,
                .field_pos = ID_AA64MMFR2_UAO_SHIFT,
                .min_field_value = 1,
                /*
                 * We rely on stop_machine() calling uao_thread_switch() to set
                 * UAO immediately after patching.
                 */
        },
#endif /* CONFIG_ARM64_UAO */
#ifdef CONFIG_ARM64_PAN
        {
                .capability = ARM64_ALT_PAN_NOT_UAO,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = cpufeature_pan_not_uao,
        },
#endif /* CONFIG_ARM64_PAN */
#ifdef CONFIG_ARM64_VHE
        {
                .desc = "Virtualization Host Extensions",
                .capability = ARM64_HAS_VIRT_HOST_EXTN,
                .type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
                .matches = runs_at_el2,
                .cpu_enable = cpu_copy_el2regs,
        },
#endif  /* CONFIG_ARM64_VHE */
        {
                .desc = "32-bit EL0 Support",
                .capability = ARM64_HAS_32BIT_EL0,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64PFR0_EL1,
                .sign = FTR_UNSIGNED,
                .field_pos = ID_AA64PFR0_EL0_SHIFT,
                .min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
        },
        {
                .desc = "Reduced HYP mapping offset",
                .capability = ARM64_HYP_OFFSET_LOW,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = hyp_offset_low,
        },
        {
                .desc = "Kernel page table isolation (KPTI)",
                .capability = ARM64_UNMAP_KERNEL_AT_EL0,
                .type = ARM64_CPUCAP_BOOT_RESTRICTED_CPU_LOCAL_FEATURE,
                /*
                 * The ID feature fields below are used to indicate that
                 * the CPU doesn't need KPTI. See unmap_kernel_at_el0 for
                 * more details.
                 */
                .sys_reg = SYS_ID_AA64PFR0_EL1,
                .field_pos = ID_AA64PFR0_CSV3_SHIFT,
                .min_field_value = 1,
                .matches = unmap_kernel_at_el0,
                .cpu_enable = kpti_install_ng_mappings,
        },
        {
                /* FP/SIMD is not implemented */
                .capability = ARM64_HAS_NO_FPSIMD,
                .type = ARM64_CPUCAP_BOOT_RESTRICTED_CPU_LOCAL_FEATURE,
                .min_field_value = 0,
                .matches = has_no_fpsimd,
        },
#ifdef CONFIG_ARM64_PMEM
        {
                .desc = "Data cache clean to Point of Persistence",
                .capability = ARM64_HAS_DCPOP,
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64ISAR1_EL1,
                .field_pos = ID_AA64ISAR1_DPB_SHIFT,
                .min_field_value = 1,
        },
#endif
#ifdef CONFIG_ARM64_SVE
        {
                .desc = "Scalable Vector Extension",
                .capability = ARM64_SVE,
                .type = ARM64_CPUCAP_SCOPE_SYSTEM,
                .sys_reg = SYS_ID_AA64PFR0_EL1,
                .sign = FTR_UNSIGNED,
                .field_pos = ID_AA64PFR0_SVE_SHIFT,
                .min_field_value = ID_AA64PFR0_SVE,
                .matches = has_cpuid_feature,
                .cpu_enable = sve_kernel_enable,
        },
#endif /* CONFIG_ARM64_SVE */
#ifdef CONFIG_ARM64_RAS_EXTN
        {
                .desc = "RAS Extension Support",
                .capability = ARM64_HAS_RAS_EXTN,
                .type = ARM64_CPUCAP_SCOPE_SYSTEM,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64PFR0_EL1,
                .sign = FTR_UNSIGNED,
                .field_pos = ID_AA64PFR0_RAS_SHIFT,
                .min_field_value = ID_AA64PFR0_RAS_V1,
                .cpu_enable = cpu_clear_disr,
        },
#endif /* CONFIG_ARM64_RAS_EXTN */
        {},
};

#define HWCAP_CAP(reg, field, s, min_value, cap_type, cap)      \
        {                                                       \
                .desc = #cap,                                   \
                .type = ARM64_CPUCAP_SYSTEM_FEATURE,            \
                .matches = has_cpuid_feature,                   \
                .sys_reg = reg,                                 \
                .field_pos = field,                             \
                .sign = s,                                      \
                .min_field_value = min_value,                   \
                .hwcap_type = cap_type,                         \
                .hwcap = cap,                                   \
        }

static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_PMULL),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_AES),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA1),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA2),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_SHA512),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_CRC32),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_ATOMICS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_ATOMICS),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_RDM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDRDM),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA3),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SM3),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM4_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SM4),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_DP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDDP),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_FHM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDFHM),
        HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_TS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FLAGM),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, HWCAP_FP),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_FPHP),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, HWCAP_ASIMD),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_ASIMDHP),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_DIT_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_DIT),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_DCPOP),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_JSCVT),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FCMA),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_LRCPC),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_ILRCPC),
        HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_USCAT),
        HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, HWCAP_SSBS),
#ifdef CONFIG_ARM64_SVE
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE),
#endif
#ifdef CONFIG_ARM64_SSBD
        {
                .desc = "Speculative Store Bypassing Safe (SSBS)",
                .capability = ARM64_SSBS,
                .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
                .matches = has_cpuid_feature,
                .sys_reg = SYS_ID_AA64PFR1_EL1,
                .field_pos = ID_AA64PFR1_SSBS_SHIFT,
                .sign = FTR_UNSIGNED,
                .min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
                .cpu_enable = cpu_enable_ssbs,
        },
#endif
        {},
};

static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = {
#ifdef CONFIG_COMPAT
        HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 2, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_PMULL),
        HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_AES),
        HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA1),
        HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA2),
        HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
#endif
        {},
};

static void __init cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap)
{
        switch (cap->hwcap_type) {
        case CAP_HWCAP:
                elf_hwcap |= cap->hwcap;
                break;
#ifdef CONFIG_COMPAT
        case CAP_COMPAT_HWCAP:
                compat_elf_hwcap |= (u32)cap->hwcap;
                break;
        case CAP_COMPAT_HWCAP2:
                compat_elf_hwcap2 |= (u32)cap->hwcap;
                break;
#endif
        default:
                WARN_ON(1);
                break;
        }
}

/* Check if we have a particular HWCAP enabled */
static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap)
{
        bool rc;

        switch (cap->hwcap_type) {
        case CAP_HWCAP:
                rc = (elf_hwcap & cap->hwcap) != 0;
                break;
#ifdef CONFIG_COMPAT
        case CAP_COMPAT_HWCAP:
                rc = (compat_elf_hwcap & (u32)cap->hwcap) != 0;
                break;
        case CAP_COMPAT_HWCAP2:
                rc = (compat_elf_hwcap2 & (u32)cap->hwcap) != 0;
                break;
#endif
        default:
                WARN_ON(1);
                rc = false;
        }

        return rc;
}

static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps)
{
        /* We support emulation of accesses to CPU ID feature registers */
        elf_hwcap |= HWCAP_CPUID;
        for (; hwcaps->matches; hwcaps++)
                if (hwcaps->matches(hwcaps, cpucap_default_scope(hwcaps)))
                        cap_set_elf_hwcap(hwcaps);
}

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

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

        for (caps = cap_array; caps->matches; caps++)
                if (caps->capability == cap &&
                    caps->matches(caps, SCOPE_LOCAL_CPU))
                        return true;
        return false;
}

static void __update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
                                      u16 scope_mask, const char *info)
{
        scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
        for (; caps->matches; caps++) {
                if (!(caps->type & scope_mask) ||
                    !caps->matches(caps, cpucap_default_scope(caps)))
                        continue;

                if (!cpus_have_cap(caps->capability) && caps->desc)
                        pr_info("%s %s\n", info, caps->desc);
                cpus_set_cap(caps->capability);
        }
}

static void update_cpu_capabilities(u16 scope_mask)
{
        __update_cpu_capabilities(arm64_errata, scope_mask,
                                  "enabling workaround for");
        __update_cpu_capabilities(arm64_features, scope_mask, "detected:");
}

static int __enable_cpu_capability(void *arg)
{
        const struct arm64_cpu_capabilities *cap = arg;

        cap->cpu_enable(cap);
        return 0;
}

/*
 * Run through the enabled capabilities and enable() it on all active
 * CPUs
 */
static void __init
__enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
                          u16 scope_mask)
{
        scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
        for (; caps->matches; caps++) {
                unsigned int num = caps->capability;

                if (!(caps->type & scope_mask) || !cpus_have_cap(num))
                        continue;

                /* Ensure cpus_have_const_cap(num) works */
                static_branch_enable(&cpu_hwcap_keys[num]);

                if (caps->cpu_enable) {
                        /*
                         * Capabilities with SCOPE_BOOT_CPU scope are finalised
                         * before any secondary CPU boots. Thus, each secondary
                         * will enable the capability as appropriate via
                         * check_local_cpu_capabilities(). The only exception is
                         * the boot CPU, for which the capability must be
                         * enabled here. This approach avoids costly
                         * stop_machine() calls for this case.
                         *
                         * Otherwise, use stop_machine() as it schedules the
                         * work allowing us to modify PSTATE, instead of
                         * on_each_cpu() which uses an IPI, giving us a PSTATE
                         * that disappears when we return.
                         */
                        if (scope_mask & SCOPE_BOOT_CPU)
                                caps->cpu_enable(caps);
                        else
                                stop_machine(__enable_cpu_capability,
                                             (void *)caps, cpu_online_mask);
                }
        }
}

static void __init enable_cpu_capabilities(u16 scope_mask)
{
        __enable_cpu_capabilities(arm64_errata, scope_mask);
        __enable_cpu_capabilities(arm64_features, scope_mask);
}

/*
 * Run through the list of capabilities to check for conflicts.
 * If the system has already detected a capability, take necessary
 * action on this CPU.
 *
 * Returns "false" on conflicts.
 */
static bool
__verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list,
                        u16 scope_mask)
{
        bool cpu_has_cap, system_has_cap;
        const struct arm64_cpu_capabilities *caps;

        scope_mask &= ARM64_CPUCAP_SCOPE_MASK;

        for (caps = caps_list; caps->matches; caps++) {
                if (!(caps->type & scope_mask))
                        continue;

                cpu_has_cap = __this_cpu_has_cap(caps_list, caps->capability);
                system_has_cap = cpus_have_cap(caps->capability);

                if (system_has_cap) {
                        /*
                         * Check if the new CPU misses an advertised feature,
                         * which is not safe to miss.
                         */
                        if (!cpu_has_cap && !cpucap_late_cpu_optional(caps))
                                break;
                        /*
                         * We have to issue cpu_enable() irrespective of
                         * whether the CPU has it or not, as it is enabeld
                         * system wide. It is upto the call back to take
                         * appropriate action on this CPU.
                         */
                        if (caps->cpu_enable)
                                caps->cpu_enable(caps);
                } else {
                        /*
                         * Check if the CPU has this capability if it isn't
                         * safe to have when the system doesn't.
                         */
                        if (cpu_has_cap && !cpucap_late_cpu_permitted(caps))
                                break;
                }
        }

        if (caps->matches) {
                pr_crit("CPU%d: Detected conflict for capability %d (%s), System: %d, CPU: %d\n",
                        smp_processor_id(), caps->capability,
                        caps->desc, system_has_cap, cpu_has_cap);
                return false;
        }

        return true;
}

static bool verify_local_cpu_caps(u16 scope_mask)
{
        return __verify_local_cpu_caps(arm64_errata, scope_mask) &&
               __verify_local_cpu_caps(arm64_features, scope_mask);
}

/*
 * Check for CPU features that are used in early boot
 * based on the Boot CPU value.
 */
static void check_early_cpu_features(void)
{
        verify_cpu_asid_bits();
        /*
         * Early features are used by the kernel already. If there
         * is a conflict, we cannot proceed further.
         */
        if (!verify_local_cpu_caps(SCOPE_BOOT_CPU))
                cpu_panic_kernel();
}

static void
verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
{

        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_sve_features(void)
{
        u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
        u64 zcr = read_zcr_features();

        unsigned int safe_len = safe_zcr & ZCR_ELx_LEN_MASK;
        unsigned int len = zcr & ZCR_ELx_LEN_MASK;

        if (len < safe_len || sve_verify_vq_map()) {
                pr_crit("CPU%d: SVE: required vector length(s) missing\n",
                        smp_processor_id());
                cpu_die_early();
        }

        /* Add checks on other ZCR bits here if necessary */
}


/*
 * 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)
{
        /*
         * The capabilities with SCOPE_BOOT_CPU are checked from
         * check_early_cpu_features(), as they need to be verified
         * on all secondary CPUs.
         */
        if (!verify_local_cpu_caps(SCOPE_ALL & ~SCOPE_BOOT_CPU))
                cpu_die_early();

        verify_local_elf_hwcaps(arm64_elf_hwcaps);

        if (system_supports_32bit_el0())
                verify_local_elf_hwcaps(compat_elf_hwcaps);

        if (system_supports_sve())
                verify_sve_features();
}

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 and local features.
         * Otherwise, this CPU should verify that it has all the system
         * advertised capabilities.
         */
        if (!sys_caps_initialised)
                update_cpu_capabilities(SCOPE_LOCAL_CPU);
        else
                verify_local_cpu_capabilities();
}

static void __init setup_boot_cpu_capabilities(void)
{
        /* Detect capabilities with either SCOPE_BOOT_CPU or SCOPE_LOCAL_CPU */
        update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
        /* Enable the SCOPE_BOOT_CPU capabilities alone right away */
        enable_cpu_capabilities(SCOPE_BOOT_CPU);
}

DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
EXPORT_SYMBOL(arm64_const_caps_ready);

static void __init mark_const_caps_ready(void)
{
        static_branch_enable(&arm64_const_caps_ready);
}

extern const struct arm64_cpu_capabilities arm64_errata[];

bool this_cpu_has_cap(unsigned int cap)
{
        return (__this_cpu_has_cap(arm64_features, cap) ||
                __this_cpu_has_cap(arm64_errata, cap));
}

static void __init setup_system_capabilities(void)
{
        /*
         * We have finalised the system-wide safe feature
         * registers, finalise the capabilities that depend
         * on it. Also enable all the available capabilities,
         * that are not enabled already.
         */
        update_cpu_capabilities(SCOPE_SYSTEM);
        enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);
}

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

        setup_system_capabilities();
        mark_const_caps_ready();
        setup_elf_hwcaps(arm64_elf_hwcaps);

        if (system_supports_32bit_el0())
                setup_elf_hwcaps(compat_elf_hwcaps);

        sve_setup();

        /* 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));
}

/*
 * We emulate only the following system register space.
 * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]
 * See Table C5-6 System instruction encodings for System register accesses,
 * ARMv8 ARM(ARM DDI 0487A.f) for more details.
 */
static inline bool __attribute_const__ is_emulated(u32 id)
{
        return (sys_reg_Op0(id) == 0x3 &&
                sys_reg_CRn(id) == 0x0 &&
                sys_reg_Op1(id) == 0x0 &&
                (sys_reg_CRm(id) == 0 ||
                 ((sys_reg_CRm(id) >= 4) && (sys_reg_CRm(id) <= 7))));
}

/*
 * With CRm == 0, reg should be one of :
 * MIDR_EL1, MPIDR_EL1 or REVIDR_EL1.
 */
static inline int emulate_id_reg(u32 id, u64 *valp)
{
        switch (id) {
        case SYS_MIDR_EL1:
                *valp = read_cpuid_id();
                break;
        case SYS_MPIDR_EL1:
                *valp = SYS_MPIDR_SAFE_VAL;
                break;
        case SYS_REVIDR_EL1:
                /* IMPLEMENTATION DEFINED values are emulated with 0 */
                *valp = 0;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int emulate_sys_reg(u32 id, u64 *valp)
{
        struct arm64_ftr_reg *regp;

        if (!is_emulated(id))
                return -EINVAL;

        if (sys_reg_CRm(id) == 0)
                return emulate_id_reg(id, valp);

        regp = get_arm64_ftr_reg(id);
        if (regp)
                *valp = arm64_ftr_reg_user_value(regp);
        else
                /*
                 * The untracked registers are either IMPLEMENTATION DEFINED
                 * (e.g, ID_AFR0_EL1) or reserved RAZ.
                 */
                *valp = 0;
        return 0;
}

static int emulate_mrs(struct pt_regs *regs, u32 insn)
{
        int rc;
        u32 sys_reg, dst;
        u64 val;

        /*
         * sys_reg values are defined as used in mrs/msr instruction.
         * shift the imm value to get the encoding.
         */
        sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5;
        rc = emulate_sys_reg(sys_reg, &val);
        if (!rc) {
                dst = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn);
                pt_regs_write_reg(regs, dst, val);
                arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
        }

        return rc;
}

static struct undef_hook mrs_hook = {
        .instr_mask = 0xfff00000,
        .instr_val  = 0xd5300000,
        .pstate_mask = COMPAT_PSR_MODE_MASK,
        .pstate_val = PSR_MODE_EL0t,
        .fn = emulate_mrs,
};

static int __init enable_mrs_emulation(void)
{
        register_undef_hook(&mrs_hook);
        return 0;
}

core_initcall(enable_mrs_emulation);

void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
{
        /* Firmware may have left a deferred SError in this register. */
        write_sysreg_s(0, SYS_DISR_EL1);
}

ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
                          char *buf)
{
        if (__meltdown_safe)
                return sprintf(buf, "Not affected\n");

        if (arm64_kernel_unmapped_at_el0())
                return sprintf(buf, "Mitigation: PTI\n");

        return sprintf(buf, "Vulnerable\n");
}