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linux/arch/arm64/kernel/cpuinfo.c
Joey Gouly 1175011a7d arm64: cpufeature: add HWCAP for FEAT_RPRES 
Add a new HWCAP to detect the Increased precision of Reciprocal Estimate
and Reciprocal Square Root Estimate feature (FEAT_RPRES), introduced in Armv8.7.

Also expose this to userspace in the ID_AA64ISAR2_EL1 feature register.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211210165432.8106-4-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-13 18:53:00 +00:00

432 lines
13 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Record and handle CPU attributes.
*
* Copyright (C) 2014 ARM Ltd.
*/
#include <asm/arch_timer.h>
#include <asm/cache.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/cpufeature.h>
#include <asm/fpsimd.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/compat.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/personality.h>
#include <linux/preempt.h>
#include <linux/printk.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/delay.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 const char *icache_policy_str[] = {
[ICACHE_POLICY_VPIPT] = "VPIPT",
[ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN",
[ICACHE_POLICY_VIPT] = "VIPT",
[ICACHE_POLICY_PIPT] = "PIPT",
};
unsigned long __icache_flags;
static const char *const hwcap_str[] = {
[KERNEL_HWCAP_FP] = "fp",
[KERNEL_HWCAP_ASIMD] = "asimd",
[KERNEL_HWCAP_EVTSTRM] = "evtstrm",
[KERNEL_HWCAP_AES] = "aes",
[KERNEL_HWCAP_PMULL] = "pmull",
[KERNEL_HWCAP_SHA1] = "sha1",
[KERNEL_HWCAP_SHA2] = "sha2",
[KERNEL_HWCAP_CRC32] = "crc32",
[KERNEL_HWCAP_ATOMICS] = "atomics",
[KERNEL_HWCAP_FPHP] = "fphp",
[KERNEL_HWCAP_ASIMDHP] = "asimdhp",
[KERNEL_HWCAP_CPUID] = "cpuid",
[KERNEL_HWCAP_ASIMDRDM] = "asimdrdm",
[KERNEL_HWCAP_JSCVT] = "jscvt",
[KERNEL_HWCAP_FCMA] = "fcma",
[KERNEL_HWCAP_LRCPC] = "lrcpc",
[KERNEL_HWCAP_DCPOP] = "dcpop",
[KERNEL_HWCAP_SHA3] = "sha3",
[KERNEL_HWCAP_SM3] = "sm3",
[KERNEL_HWCAP_SM4] = "sm4",
[KERNEL_HWCAP_ASIMDDP] = "asimddp",
[KERNEL_HWCAP_SHA512] = "sha512",
[KERNEL_HWCAP_SVE] = "sve",
[KERNEL_HWCAP_ASIMDFHM] = "asimdfhm",
[KERNEL_HWCAP_DIT] = "dit",
[KERNEL_HWCAP_USCAT] = "uscat",
[KERNEL_HWCAP_ILRCPC] = "ilrcpc",
[KERNEL_HWCAP_FLAGM] = "flagm",
[KERNEL_HWCAP_SSBS] = "ssbs",
[KERNEL_HWCAP_SB] = "sb",
[KERNEL_HWCAP_PACA] = "paca",
[KERNEL_HWCAP_PACG] = "pacg",
[KERNEL_HWCAP_DCPODP] = "dcpodp",
[KERNEL_HWCAP_SVE2] = "sve2",
[KERNEL_HWCAP_SVEAES] = "sveaes",
[KERNEL_HWCAP_SVEPMULL] = "svepmull",
[KERNEL_HWCAP_SVEBITPERM] = "svebitperm",
[KERNEL_HWCAP_SVESHA3] = "svesha3",
[KERNEL_HWCAP_SVESM4] = "svesm4",
[KERNEL_HWCAP_FLAGM2] = "flagm2",
[KERNEL_HWCAP_FRINT] = "frint",
[KERNEL_HWCAP_SVEI8MM] = "svei8mm",
[KERNEL_HWCAP_SVEF32MM] = "svef32mm",
[KERNEL_HWCAP_SVEF64MM] = "svef64mm",
[KERNEL_HWCAP_SVEBF16] = "svebf16",
[KERNEL_HWCAP_I8MM] = "i8mm",
[KERNEL_HWCAP_BF16] = "bf16",
[KERNEL_HWCAP_DGH] = "dgh",
[KERNEL_HWCAP_RNG] = "rng",
[KERNEL_HWCAP_BTI] = "bti",
[KERNEL_HWCAP_MTE] = "mte",
[KERNEL_HWCAP_ECV] = "ecv",
[KERNEL_HWCAP_AFP] = "afp",
[KERNEL_HWCAP_RPRES] = "rpres",
};
#ifdef CONFIG_COMPAT
#define COMPAT_KERNEL_HWCAP(x) const_ilog2(COMPAT_HWCAP_ ## x)
static const char *const compat_hwcap_str[] = {
[COMPAT_KERNEL_HWCAP(SWP)] = "swp",
[COMPAT_KERNEL_HWCAP(HALF)] = "half",
[COMPAT_KERNEL_HWCAP(THUMB)] = "thumb",
[COMPAT_KERNEL_HWCAP(26BIT)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(FAST_MULT)] = "fastmult",
[COMPAT_KERNEL_HWCAP(FPA)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(VFP)] = "vfp",
[COMPAT_KERNEL_HWCAP(EDSP)] = "edsp",
[COMPAT_KERNEL_HWCAP(JAVA)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(IWMMXT)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(CRUNCH)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(THUMBEE)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(NEON)] = "neon",
[COMPAT_KERNEL_HWCAP(VFPv3)] = "vfpv3",
[COMPAT_KERNEL_HWCAP(VFPV3D16)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(TLS)] = "tls",
[COMPAT_KERNEL_HWCAP(VFPv4)] = "vfpv4",
[COMPAT_KERNEL_HWCAP(IDIVA)] = "idiva",
[COMPAT_KERNEL_HWCAP(IDIVT)] = "idivt",
[COMPAT_KERNEL_HWCAP(VFPD32)] = NULL, /* Not possible on arm64 */
[COMPAT_KERNEL_HWCAP(LPAE)] = "lpae",
[COMPAT_KERNEL_HWCAP(EVTSTRM)] = "evtstrm",
};
#define COMPAT_KERNEL_HWCAP2(x) const_ilog2(COMPAT_HWCAP2_ ## x)
static const char *const compat_hwcap2_str[] = {
[COMPAT_KERNEL_HWCAP2(AES)] = "aes",
[COMPAT_KERNEL_HWCAP2(PMULL)] = "pmull",
[COMPAT_KERNEL_HWCAP2(SHA1)] = "sha1",
[COMPAT_KERNEL_HWCAP2(SHA2)] = "sha2",
[COMPAT_KERNEL_HWCAP2(CRC32)] = "crc32",
};
#endif /* CONFIG_COMPAT */
static int c_show(struct seq_file *m, void *v)
{
int i, j;
bool compat = personality(current->personality) == PER_LINUX32;
for_each_online_cpu(i) {
struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i);
u32 midr = cpuinfo->reg_midr;
/*
* glibc reads /proc/cpuinfo to determine the number of
* online processors, looking for lines beginning with
* "processor". Give glibc what it expects.
*/
seq_printf(m, "processor\t: %d\n", i);
if (compat)
seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n",
MIDR_REVISION(midr), COMPAT_ELF_PLATFORM);
seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
loops_per_jiffy / (500000UL/HZ),
loops_per_jiffy / (5000UL/HZ) % 100);
/*
* Dump out the common processor features in a single line.
* Userspace should read the hwcaps with getauxval(AT_HWCAP)
* rather than attempting to parse this, but there's a body of
* software which does already (at least for 32-bit).
*/
seq_puts(m, "Features\t:");
if (compat) {
#ifdef CONFIG_COMPAT
for (j = 0; j < ARRAY_SIZE(compat_hwcap_str); j++) {
if (compat_elf_hwcap & (1 << j)) {
/*
* Warn once if any feature should not
* have been present on arm64 platform.
*/
if (WARN_ON_ONCE(!compat_hwcap_str[j]))
continue;
seq_printf(m, " %s", compat_hwcap_str[j]);
}
}
for (j = 0; j < ARRAY_SIZE(compat_hwcap2_str); j++)
if (compat_elf_hwcap2 & (1 << j))
seq_printf(m, " %s", compat_hwcap2_str[j]);
#endif /* CONFIG_COMPAT */
} else {
for (j = 0; j < ARRAY_SIZE(hwcap_str); j++)
if (cpu_have_feature(j))
seq_printf(m, " %s", hwcap_str[j]);
}
seq_puts(m, "\n");
seq_printf(m, "CPU implementer\t: 0x%02x\n",
MIDR_IMPLEMENTOR(midr));
seq_printf(m, "CPU architecture: 8\n");
seq_printf(m, "CPU variant\t: 0x%x\n", MIDR_VARIANT(midr));
seq_printf(m, "CPU part\t: 0x%03x\n", MIDR_PARTNUM(midr));
seq_printf(m, "CPU revision\t: %d\n\n", MIDR_REVISION(midr));
}
return 0;
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
return *pos < 1 ? (void *)1 : NULL;
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
++*pos;
return NULL;
}
static void c_stop(struct seq_file *m, void *v)
{
}
const struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = c_show
};
static struct kobj_type cpuregs_kobj_type = {
.sysfs_ops = &kobj_sysfs_ops,
};
/*
* The ARM ARM uses the phrase "32-bit register" to describe a register
* whose upper 32 bits are RES0 (per C5.1.1, ARM DDI 0487A.i), however
* no statement is made as to whether the upper 32 bits will or will not
* be made use of in future, and between ARM DDI 0487A.c and ARM DDI
* 0487A.d CLIDR_EL1 was expanded from 32-bit to 64-bit.
*
* Thus, while both MIDR_EL1 and REVIDR_EL1 are described as 32-bit
* registers, we expose them both as 64 bit values to cater for possible
* future expansion without an ABI break.
*/
#define kobj_to_cpuinfo(kobj) container_of(kobj, struct cpuinfo_arm64, kobj)
#define CPUREGS_ATTR_RO(_name, _field) \
static ssize_t _name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
struct cpuinfo_arm64 *info = kobj_to_cpuinfo(kobj); \
\
if (info->reg_midr) \
return sprintf(buf, "0x%016llx\n", info->reg_##_field); \
else \
return 0; \
} \
static struct kobj_attribute cpuregs_attr_##_name = __ATTR_RO(_name)
CPUREGS_ATTR_RO(midr_el1, midr);
CPUREGS_ATTR_RO(revidr_el1, revidr);
static struct attribute *cpuregs_id_attrs[] = {
&cpuregs_attr_midr_el1.attr,
&cpuregs_attr_revidr_el1.attr,
NULL
};
static const struct attribute_group cpuregs_attr_group = {
.attrs = cpuregs_id_attrs,
.name = "identification"
};
static int cpuid_cpu_online(unsigned int cpu)
{
int rc;
struct device *dev;
struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
dev = get_cpu_device(cpu);
if (!dev) {
rc = -ENODEV;
goto out;
}
rc = kobject_add(&info->kobj, &dev->kobj, "regs");
if (rc)
goto out;
rc = sysfs_create_group(&info->kobj, &cpuregs_attr_group);
if (rc)
kobject_del(&info->kobj);
out:
return rc;
}
static int cpuid_cpu_offline(unsigned int cpu)
{
struct device *dev;
struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
dev = get_cpu_device(cpu);
if (!dev)
return -ENODEV;
if (info->kobj.parent) {
sysfs_remove_group(&info->kobj, &cpuregs_attr_group);
kobject_del(&info->kobj);
}
return 0;
}
static int __init cpuinfo_regs_init(void)
{
int cpu, ret;
for_each_possible_cpu(cpu) {
struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
kobject_init(&info->kobj, &cpuregs_kobj_type);
}
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/cpuinfo:online",
cpuid_cpu_online, cpuid_cpu_offline);
if (ret < 0) {
pr_err("cpuinfo: failed to register hotplug callbacks.\n");
return ret;
}
return 0;
}
device_initcall(cpuinfo_regs_init);
static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
{
unsigned int cpu = smp_processor_id();
u32 l1ip = CTR_L1IP(info->reg_ctr);
switch (l1ip) {
case ICACHE_POLICY_PIPT:
break;
case ICACHE_POLICY_VPIPT:
set_bit(ICACHEF_VPIPT, &__icache_flags);
break;
case ICACHE_POLICY_RESERVED:
case ICACHE_POLICY_VIPT:
/* Assume aliasing */
set_bit(ICACHEF_ALIASING, &__icache_flags);
break;
}
pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu);
}
static void __cpuinfo_store_cpu_32bit(struct cpuinfo_32bit *info)
{
info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
info->reg_id_dfr1 = read_cpuid(ID_DFR1_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_isar6 = read_cpuid(ID_ISAR6_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_mmfr4 = read_cpuid(ID_MMFR4_EL1);
info->reg_id_mmfr5 = read_cpuid(ID_MMFR5_EL1);
info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
info->reg_id_pfr2 = read_cpuid(ID_PFR2_EL1);
info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
}
static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
{
info->reg_cntfrq = arch_timer_get_cntfrq();
/*
* Use the effective value of the CTR_EL0 than the raw value
* exposed by the CPU. CTR_EL0.IDC field value must be interpreted
* with the CLIDR_EL1 fields to avoid triggering false warnings
* when there is a mismatch across the CPUs. Keep track of the
* effective value of the CTR_EL0 in our internal records for
* accurate sanity check and feature enablement.
*/
info->reg_ctr = read_cpuid_effective_cachetype();
info->reg_dczid = read_cpuid(DCZID_EL0);
info->reg_midr = read_cpuid_id();
info->reg_revidr = read_cpuid(REVIDR_EL1);
info->reg_id_aa64dfr0 = read_cpuid(ID_AA64DFR0_EL1);
info->reg_id_aa64dfr1 = read_cpuid(ID_AA64DFR1_EL1);
info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
info->reg_id_aa64isar2 = read_cpuid(ID_AA64ISAR2_EL1);
info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
info->reg_id_aa64mmfr2 = read_cpuid(ID_AA64MMFR2_EL1);
info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1);
if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
info->reg_gmid = read_cpuid(GMID_EL1);
if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0))
__cpuinfo_store_cpu_32bit(&info->aarch32);
if (IS_ENABLED(CONFIG_ARM64_SVE) &&
id_aa64pfr0_sve(info->reg_id_aa64pfr0))
info->reg_zcr = read_zcr_features();
cpuinfo_detect_icache_policy(info);
}
void cpuinfo_store_cpu(void)
{
struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
__cpuinfo_store_cpu(info);
update_cpu_features(smp_processor_id(), info, &boot_cpu_data);
}
void __init cpuinfo_store_boot_cpu(void)
{
struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
__cpuinfo_store_cpu(info);
boot_cpu_data = *info;
init_cpu_features(&boot_cpu_data);
}
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