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/*
* Record and handle CPU attributes.
*
* Copyright (C) 2014 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/>.
*/
#include <asm/arch_timer.h>
#include <asm/cachetype.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/smp.h>
/*
* In case the boot CPU is hotpluggable, we record its initial state and
* current state separately. Certain system registers may contain different
* values depending on configuration at or after reset.
*/
DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
static struct cpuinfo_arm64 boot_cpu_data;
static char *icache_policy_str[] = {
[ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN",
[ICACHE_POLICY_AIVIVT] = "AIVIVT",
[ICACHE_POLICY_VIPT] = "VIPT",
[ICACHE_POLICY_PIPT] = "PIPT",
};
unsigned long __icache_flags;
static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
{
unsigned int cpu = smp_processor_id();
u32 l1ip = CTR_L1IP(info->reg_ctr);
if (l1ip != ICACHE_POLICY_PIPT)
set_bit(ICACHEF_ALIASING, &__icache_flags);
if (l1ip == ICACHE_POLICY_AIVIVT);
set_bit(ICACHEF_AIVIVT, &__icache_flags);
pr_info("Detected %s I-cache on CPU%d", icache_policy_str[l1ip], cpu);
}
static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu)
{
if ((boot & mask) == (cur & mask))
return 0;
pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016lx, CPU%d: %#016lx\n",
name, (unsigned long)boot, cpu, (unsigned long)cur);
return 1;
}
#define CHECK_MASK(field, mask, boot, cur, cpu) \
check_reg_mask(#field, mask, (boot)->reg_ ## field, (cur)->reg_ ## field, cpu)
#define CHECK(field, boot, cur, cpu) \
CHECK_MASK(field, ~0ULL, boot, cur, cpu)
/*
* Verify that CPUs don't have unexpected differences that will cause problems.
*/
static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur)
{
unsigned int cpu = smp_processor_id();
struct cpuinfo_arm64 *boot = &boot_cpu_data;
unsigned int diff = 0;
/*
* The kernel can handle differing I-cache policies, but otherwise
* caches should look identical. Userspace JITs will make use of
* *minLine.
*/
diff |= CHECK_MASK(ctr, 0xffff3fff, boot, cur, cpu);
/*
* 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.
*/
diff |= CHECK(dczid, boot, cur, cpu);
/* If different, timekeeping will be broken (especially with KVM) */
diff |= CHECK(cntfrq, boot, cur, cpu);
/*
* Even in big.LITTLE, processors should be identical instruction-set
* wise.
*/
diff |= CHECK(id_aa64isar0, boot, cur, cpu);
diff |= CHECK(id_aa64isar1, boot, cur, cpu);
/*
* 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.
* ID_AA64MMFR1 is currently RES0.
*/
diff |= CHECK_MASK(id_aa64mmfr0, 0xffffffffffff0ff0, boot, cur, cpu);
diff |= CHECK(id_aa64mmfr1, boot, cur, cpu);
/*
* EL3 is not our concern.
* ID_AA64PFR1 is currently RES0.
*/
diff |= CHECK_MASK(id_aa64pfr0, 0xffffffffffff0fff, boot, cur, cpu);
diff |= CHECK(id_aa64pfr1, boot, cur, cpu);
/*
* If we have AArch32, we care about 32-bit features for compat. These
* registers should be RES0 otherwise.
*/
diff |= CHECK(id_isar0, boot, cur, cpu);
diff |= CHECK(id_isar1, boot, cur, cpu);
diff |= CHECK(id_isar2, boot, cur, cpu);
diff |= CHECK(id_isar3, boot, cur, cpu);
diff |= CHECK(id_isar4, boot, cur, cpu);
diff |= CHECK(id_isar5, boot, cur, cpu);
diff |= CHECK(id_mmfr0, boot, cur, cpu);
diff |= CHECK(id_mmfr1, boot, cur, cpu);
diff |= CHECK(id_mmfr2, boot, cur, cpu);
diff |= CHECK(id_mmfr3, boot, cur, cpu);
diff |= CHECK(id_pfr0, boot, cur, cpu);
diff |= CHECK(id_pfr1, boot, cur, cpu);
/*
* Mismatched CPU features are a recipe for disaster. Don't even
* pretend to support them.
*/
WARN_TAINT_ONCE(diff, TAINT_CPU_OUT_OF_SPEC,
"Unsupported CPU feature variation.");
}
static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
{
info->reg_cntfrq = arch_timer_get_cntfrq();
info->reg_ctr = read_cpuid_cachetype();
info->reg_dczid = read_cpuid(DCZID_EL0);
info->reg_midr = read_cpuid_id();
info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
cpuinfo_detect_icache_policy(info);
}
void cpuinfo_store_cpu(void)
{
struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
__cpuinfo_store_cpu(info);
cpuinfo_sanity_check(info);
}
void __init cpuinfo_store_boot_cpu(void)
{
struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
__cpuinfo_store_cpu(info);
boot_cpu_data = *info;
}
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