/*
* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
*
* 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.
*/
#ifndef __ASM_CPUFEATURE_H
#define __ASM_CPUFEATURE_H
#include <asm/cpucaps.h>
#include <asm/hwcap.h>
#include <asm/sysreg.h>
/*
* In the arm64 world (as in the ARM world), elf_hwcap is used both internally
* in the kernel and for user space to keep track of which optional features
* are supported by the current system. So let's map feature 'x' to HWCAP_x.
* Note that HWCAP_x constants are bit fields so we need to take the log.
*/
#define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
#define cpu_feature(x) ilog2(HWCAP_ ## x)
#ifndef __ASSEMBLY__
#include <linux/bug.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
/*
* CPU feature register tracking
*
* The safe value of a CPUID feature field is dependent on the implications
* of the values assigned to it by the architecture. Based on the relationship
* between the values, the features are classified into 3 types - LOWER_SAFE,
* HIGHER_SAFE and EXACT.
*
* The lowest value of all the CPUs is chosen for LOWER_SAFE and highest
* for HIGHER_SAFE. It is expected that all CPUs have the same value for
* a field when EXACT is specified, failing which, the safe value specified
* in the table is chosen.
*/
enum ftr_type {
FTR_EXACT, /* Use a predefined safe value */
FTR_LOWER_SAFE, /* Smaller value is safe */
FTR_HIGHER_SAFE,/* Bigger value is safe */
};
#define FTR_STRICT true /* SANITY check strict matching required */
#define FTR_NONSTRICT false /* SANITY check ignored */
#define FTR_SIGNED true /* Value should be treated as signed */
#define FTR_UNSIGNED false /* Value should be treated as unsigned */
#define FTR_VISIBLE true /* Feature visible to the user space */
#define FTR_HIDDEN false /* Feature is hidden from the user */
struct arm64_ftr_bits {
bool sign; /* Value is signed ? */
bool visible;
bool strict; /* CPU Sanity check: strict matching required ? */
enum ftr_type type;
u8 shift;
u8 width;
s64 safe_val; /* safe value for FTR_EXACT features */
};
/*
* @arm64_ftr_reg - Feature register
* @strict_mask Bits which should match across all CPUs for sanity.
* @sys_val Safe value across the CPUs (system view)
*/
struct arm64_ftr_reg {
const char *name;
u64 strict_mask;
u64 user_mask;
u64 sys_val;
u64 user_val;
const struct arm64_ftr_bits *ftr_bits;
};
extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
/* scope of capability check */
enum {
SCOPE_SYSTEM,
SCOPE_LOCAL_CPU,
};
struct arm64_cpu_capabilities {
const char *desc;
u16 capability;
int def_scope; /* default scope */
bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
int (*enable)(void *); /* Called on all active CPUs */
union {
struct { /* To be used for erratum handling only */
u32 midr_model;
u32 midr_range_min, midr_range_max;
};
struct { /* Feature register checking */
u32 sys_reg;
u8 field_pos;
u8 min_field_value;
u8 hwcap_type;
bool sign;
unsigned long hwcap;
};
};
};
extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS];
extern struct static_key_false arm64_const_caps_ready;
bool this_cpu_has_cap(unsigned int cap);
static inline bool cpu_have_feature(unsigned int num)
{
return elf_hwcap & (1UL << num);
}
/* System capability check for constant caps */
static inline bool __cpus_have_const_cap(int num)
{
if (num >= ARM64_NCAPS)
return false;
return static_branch_unlikely(&cpu_hwcap_keys[num]);
}
static inline bool cpus_have_cap(unsigned int num)
{
if (num >= ARM64_NCAPS)
return false;
return test_bit(num, cpu_hwcaps);
}
static inline bool cpus_have_const_cap(int num)
{
if (static_branch_likely(&arm64_const_caps_ready))
return __cpus_have_const_cap(num);
else
return cpus_have_cap(num);
}
static inline void cpus_set_cap(unsigned int num)
{
if (num >= ARM64_NCAPS) {
pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
num, ARM64_NCAPS);
} else {
__set_bit(num, cpu_hwcaps);
}
}
static inline int __attribute_const__
cpuid_feature_extract_signed_field_width(u64 features, int field, int width)
{
return (s64)(features << (64 - width - field)) >> (64 - width);
}
static inline int __attribute_const__
cpuid_feature_extract_signed_field(u64 features, int field)
{
return cpuid_feature_extract_signed_field_width(features, field, 4);
}
static inline unsigned int __attribute_const__
cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
{
return (u64)(features << (64 - width - field)) >> (64 - width);
}
static inline unsigned int __attribute_const__
cpuid_feature_extract_unsigned_field(u64 features, int field)
{
return cpuid_feature_extract_unsigned_field_width(features, field, 4);
}
static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
{
return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
}
static inline u64 arm64_ftr_reg_user_value(const struct arm64_ftr_reg *reg)
{
return (reg->user_val | (reg->sys_val & reg->user_mask));
}
static inline int __attribute_const__
cpuid_feature_extract_field_width(u64 features, int field, int width, bool sign)
{
return (sign) ?
cpuid_feature_extract_signed_field_width(features, field, width) :
cpuid_feature_extract_unsigned_field_width(features, field, width);
}
static inline int __attribute_const__
cpuid_feature_extract_field(u64 features, int field, bool sign)
{
return cpuid_feature_extract_field_width(features, field, 4, sign);
}
static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val)
{
return (s64)cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width, ftrp->sign);
}
static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
{
return cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
}
static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
{
u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
return val == ID_AA64PFR0_EL0_32BIT_64BIT;
}
void __init setup_cpu_features(void);
void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
const char *info);
void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps);
void check_local_cpu_capabilities(void);
void update_cpu_errata_workarounds(void);
void __init enable_errata_workarounds(void);
void verify_local_cpu_errata_workarounds(void);
u64 read_sanitised_ftr_reg(u32 id);
static inline bool cpu_supports_mixed_endian_el0(void)
{
return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
}
static inline bool system_supports_32bit_el0(void)
{
return cpus_have_const_cap(ARM64_HAS_32BIT_EL0);
}
static inline bool system_supports_mixed_endian_el0(void)
{
return id_aa64mmfr0_mixed_endian_el0(read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1));
}
static inline bool system_supports_fpsimd(void)
{
return !cpus_have_const_cap(ARM64_HAS_NO_FPSIMD);
}
static inline bool system_uses_ttbr0_pan(void)
{
return IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN) &&
!cpus_have_const_cap(ARM64_HAS_PAN);
}
#endif /* __ASSEMBLY__ */
#endif
