/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
*/
#ifndef __ASM_CPUFEATURE_H
#define __ASM_CPUFEATURE_H
#include <asm/cpucaps.h>
#include <asm/cputype.h>
#include <asm/hwcap.h>
#include <asm/sysreg.h>
#define MAX_CPU_FEATURES 64
#define cpu_feature(x) KERNEL_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 */
FTR_HIGHER_OR_ZERO_SAFE, /* Bigger value is safe, but 0 is biggest */
};
#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 */
#define FTR_VISIBLE_IF_IS_ENABLED(config) \
(IS_ENABLED(config) ? FTR_VISIBLE : FTR_HIDDEN)
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;
/*
* CPU capabilities:
*
* We use arm64_cpu_capabilities to represent system features, errata work
* arounds (both used internally by kernel and tracked in cpu_hwcaps) and
* ELF HWCAPs (which are exposed to user).
*
* To support systems with heterogeneous CPUs, we need to make sure that we
* detect the capabilities correctly on the system and take appropriate
* measures to ensure there are no incompatibilities.
*
* This comment tries to explain how we treat the capabilities.
* Each capability has the following list of attributes :
*
* 1) Scope of Detection : The system detects a given capability by
* performing some checks at runtime. This could be, e.g, checking the
* value of a field in CPU ID feature register or checking the cpu
* model. The capability provides a call back ( @matches() ) to
* perform the check. Scope defines how the checks should be performed.
* There are three cases:
*
* a) SCOPE_LOCAL_CPU: check all the CPUs and "detect" if at least one
* matches. This implies, we have to run the check on all the
* booting CPUs, until the system decides that state of the
* capability is finalised. (See section 2 below)
* Or
* b) SCOPE_SYSTEM: check all the CPUs and "detect" if all the CPUs
* matches. This implies, we run the check only once, when the
* system decides to finalise the state of the capability. If the
* capability relies on a field in one of the CPU ID feature
* registers, we use the sanitised value of the register from the
* CPU feature infrastructure to make the decision.
* Or
* c) SCOPE_BOOT_CPU: Check only on the primary boot CPU to detect the
* feature. This category is for features that are "finalised"
* (or used) by the kernel very early even before the SMP cpus
* are brought up.
*
* The process of detection is usually denoted by "update" capability
* state in the code.
*
* 2) Finalise the state : The kernel should finalise the state of a
* capability at some point during its execution and take necessary
* actions if any. Usually, this is done, after all the boot-time
* enabled CPUs are brought up by the kernel, so that it can make
* better decision based on the available set of CPUs. However, there
* are some special cases, where the action is taken during the early
* boot by the primary boot CPU. (e.g, running the kernel at EL2 with
* Virtualisation Host Extensions). The kernel usually disallows any
* changes to the state of a capability once it finalises the capability
* and takes any action, as it may be impossible to execute the actions
* safely. A CPU brought up after a capability is "finalised" is
* referred to as "Late CPU" w.r.t the capability. e.g, all secondary
* CPUs are treated "late CPUs" for capabilities determined by the boot
* CPU.
*
* At the moment there are two passes of finalising the capabilities.
* a) Boot CPU scope capabilities - Finalised by primary boot CPU via
* setup_boot_cpu_capabilities().
* b) Everything except (a) - Run via setup_system_capabilities().
*
* 3) Verification: When a CPU is brought online (e.g, by user or by the
* kernel), the kernel should make sure that it is safe to use the CPU,
* by verifying that the CPU is compliant with the state of the
* capabilities finalised already. This happens via :
*
* secondary_start_kernel()-> check_local_cpu_capabilities()
*
* As explained in (2) above, capabilities could be finalised at
* different points in the execution. Each newly booted CPU is verified
* against the capabilities that have been finalised by the time it
* boots.
*
* a) SCOPE_BOOT_CPU : All CPUs are verified against the capability
* except for the primary boot CPU.
*
* b) SCOPE_LOCAL_CPU, SCOPE_SYSTEM: All CPUs hotplugged on by the
* user after the kernel boot are verified against the capability.
*
* If there is a conflict, the kernel takes an action, based on the
* severity (e.g, a CPU could be prevented from booting or cause a
* kernel panic). The CPU is allowed to "affect" the state of the
* capability, if it has not been finalised already. See section 5
* for more details on conflicts.
*
* 4) Action: As mentioned in (2), the kernel can take an action for each
* detected capability, on all CPUs on the system. Appropriate actions
* include, turning on an architectural feature, modifying the control
* registers (e.g, SCTLR, TCR etc.) or patching the kernel via
* alternatives. The kernel patching is batched and performed at later
* point. The actions are always initiated only after the capability
* is finalised. This is usally denoted by "enabling" the capability.
* The actions are initiated as follows :
* a) Action is triggered on all online CPUs, after the capability is
* finalised, invoked within the stop_machine() context from
* enable_cpu_capabilitie().
*
* b) Any late CPU, brought up after (1), the action is triggered via:
*
* check_local_cpu_capabilities() -> verify_local_cpu_capabilities()
*
* 5) Conflicts: Based on the state of the capability on a late CPU vs.
* the system state, we could have the following combinations :
*
* x-----------------------------x
* | Type | System | Late CPU |
* |-----------------------------|
* | a | y | n |
* |-----------------------------|
* | b | n | y |
* x-----------------------------x
*
* Two separate flag bits are defined to indicate whether each kind of
* conflict can be allowed:
* ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU - Case(a) is allowed
* ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU - Case(b) is allowed
*
* Case (a) is not permitted for a capability that the system requires
* all CPUs to have in order for the capability to be enabled. This is
* typical for capabilities that represent enhanced functionality.
*
* Case (b) is not permitted for a capability that must be enabled
* during boot if any CPU in the system requires it in order to run
* safely. This is typical for erratum work arounds that cannot be
* enabled after the corresponding capability is finalised.
*
* In some non-typical cases either both (a) and (b), or neither,
* should be permitted. This can be described by including neither
* or both flags in the capability's type field.
*/
/*
* Decide how the capability is detected.
* On any local CPU vs System wide vs the primary boot CPU
*/
#define ARM64_CPUCAP_SCOPE_LOCAL_CPU ((u16)BIT(0))
#define ARM64_CPUCAP_SCOPE_SYSTEM ((u16)BIT(1))
/*
* The capabilitiy is detected on the Boot CPU and is used by kernel
* during early boot. i.e, the capability should be "detected" and
* "enabled" as early as possibly on all booting CPUs.
*/
#define ARM64_CPUCAP_SCOPE_BOOT_CPU ((u16)BIT(2))
#define ARM64_CPUCAP_SCOPE_MASK \
(ARM64_CPUCAP_SCOPE_SYSTEM | \
ARM64_CPUCAP_SCOPE_LOCAL_CPU | \
ARM64_CPUCAP_SCOPE_BOOT_CPU)
#define SCOPE_SYSTEM ARM64_CPUCAP_SCOPE_SYSTEM
#define SCOPE_LOCAL_CPU ARM64_CPUCAP_SCOPE_LOCAL_CPU
#define SCOPE_BOOT_CPU ARM64_CPUCAP_SCOPE_BOOT_CPU
#define SCOPE_ALL ARM64_CPUCAP_SCOPE_MASK
/*
* Is it permitted for a late CPU to have this capability when system
* hasn't already enabled it ?
*/
#define ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU ((u16)BIT(4))
/* Is it safe for a late CPU to miss this capability when system has it */
#define ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU ((u16)BIT(5))
/*
* CPU errata workarounds that need to be enabled at boot time if one or
* more CPUs in the system requires it. When one of these capabilities
* has been enabled, it is safe to allow any CPU to boot that doesn't
* require the workaround. However, it is not safe if a "late" CPU
* requires a workaround and the system hasn't enabled it already.
*/
#define ARM64_CPUCAP_LOCAL_CPU_ERRATUM \
(ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU)
/*
* CPU feature detected at boot time based on system-wide value of a
* feature. It is safe for a late CPU to have this feature even though
* the system hasn't enabled it, although the feature will not be used
* by Linux in this case. If the system has enabled this feature already,
* then every late CPU must have it.
*/
#define ARM64_CPUCAP_SYSTEM_FEATURE \
(ARM64_CPUCAP_SCOPE_SYSTEM | ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU)
/*
* CPU feature detected at boot time based on feature of one or more CPUs.
* All possible conflicts for a late CPU are ignored.
*/
#define ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE \
(ARM64_CPUCAP_SCOPE_LOCAL_CPU | \
ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU | \
ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU)
/*
* CPU feature detected at boot time, on one or more CPUs. A late CPU
* is not allowed to have the capability when the system doesn't have it.
* It is Ok for a late CPU to miss the feature.
*/
#define ARM64_CPUCAP_BOOT_RESTRICTED_CPU_LOCAL_FEATURE \
(ARM64_CPUCAP_SCOPE_LOCAL_CPU | \
ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU)
/*
* CPU feature used early in the boot based on the boot CPU. All secondary
* CPUs must match the state of the capability as detected by the boot CPU.
*/
#define ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE ARM64_CPUCAP_SCOPE_BOOT_CPU
struct arm64_cpu_capabilities {
const char *desc;
u16 capability;
u16 type;
bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
/*
* Take the appropriate actions to enable this capability for this CPU.
* For each successfully booted CPU, this method is called for each
* globally detected capability.
*/
void (*cpu_enable)(const struct arm64_cpu_capabilities *cap);
union {
struct { /* To be used for erratum handling only */
struct midr_range midr_range;
const struct arm64_midr_revidr {
u32 midr_rv; /* revision/variant */
u32 revidr_mask;
} * const fixed_revs;
};
const struct midr_range *midr_range_list;
struct { /* Feature register checking */
u32 sys_reg;
u8 field_pos;
u8 min_field_value;
u8 hwcap_type;
bool sign;
unsigned long hwcap;
};
};
/*
* An optional list of "matches/cpu_enable" pair for the same
* "capability" of the same "type" as described by the parent.
* Only matches(), cpu_enable() and fields relevant to these
* methods are significant in the list. The cpu_enable is
* invoked only if the corresponding entry "matches()".
* However, if a cpu_enable() method is associated
* with multiple matches(), care should be taken that either
* the match criteria are mutually exclusive, or that the
* method is robust against being called multiple times.
*/
const struct arm64_cpu_capabilities *match_list;
};
static inline int cpucap_default_scope(const struct arm64_cpu_capabilities *cap)
{
return cap->type & ARM64_CPUCAP_SCOPE_MASK;
}
static inline bool
cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap)
{
return !!(cap->type & ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU);
}
static inline bool
cpucap_late_cpu_permitted(const struct arm64_cpu_capabilities *cap)
{
return !!(cap->type & ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU);
}
/*
* Generic helper for handling capabilties with multiple (match,enable) pairs
* of call backs, sharing the same capability bit.
* Iterate over each entry to see if at least one matches.
*/
static inline bool
cpucap_multi_entry_cap_matches(const struct arm64_cpu_capabilities *entry,
int scope)
{
const struct arm64_cpu_capabilities *caps;
for (caps = entry->match_list; caps->matches; caps++)
if (caps->matches(caps, scope))
return true;
return false;
}
/*
* Take appropriate action for all matching entries in the shared capability
* entry.
*/
static inline void
cpucap_multi_entry_cap_cpu_enable(const struct arm64_cpu_capabilities *entry)
{
const struct arm64_cpu_capabilities *caps;
for (caps = entry->match_list; caps->matches; caps++)
if (caps->matches(caps, SCOPE_LOCAL_CPU) &&
caps->cpu_enable)
caps->cpu_enable(caps);
}
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;
/* ARM64 CAPS + alternative_cb */
#define ARM64_NPATCHABLE (ARM64_NCAPS + 1)
extern DECLARE_BITMAP(boot_capabilities, ARM64_NPATCHABLE);
#define for_each_available_cap(cap) \
for_each_set_bit(cap, cpu_hwcaps, ARM64_NCAPS)
bool this_cpu_has_cap(unsigned int cap);
void cpu_set_feature(unsigned int num);
bool cpu_have_feature(unsigned int num);
unsigned long cpu_get_elf_hwcap(void);
unsigned long cpu_get_elf_hwcap2(void);
#define cpu_set_named_feature(name) cpu_set_feature(cpu_feature(name))
#define cpu_have_named_feature(name) cpu_have_feature(cpu_feature(name))
/* System capability check for constant caps */
static __always_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 __always_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;
}
static inline bool id_aa64pfr0_sve(u64 pfr0)
{
u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_SVE_SHIFT);
return val > 0;
}
void __init setup_cpu_features(void);
void check_local_cpu_capabilities(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_4kb_granule(void)
{
u64 mmfr0;
u32 val;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
val = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_TGRAN4_SHIFT);
return val == ID_AA64MMFR0_TGRAN4_SUPPORTED;
}
static inline bool system_supports_64kb_granule(void)
{
u64 mmfr0;
u32 val;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
val = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_TGRAN64_SHIFT);
return val == ID_AA64MMFR0_TGRAN64_SUPPORTED;
}
static inline bool system_supports_16kb_granule(void)
{
u64 mmfr0;
u32 val;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
val = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_TGRAN16_SHIFT);
return val == ID_AA64MMFR0_TGRAN16_SUPPORTED;
}
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_mixed_endian(void)
{
u64 mmfr0;
u32 val;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
val = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_BIGENDEL_SHIFT);
return val == 0x1;
}
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);
}
static inline bool system_supports_sve(void)
{
return IS_ENABLED(CONFIG_ARM64_SVE) &&
cpus_have_const_cap(ARM64_SVE);
}
static inline bool system_supports_cnp(void)
{
return IS_ENABLED(CONFIG_ARM64_CNP) &&
cpus_have_const_cap(ARM64_HAS_CNP);
}
static inline bool system_supports_address_auth(void)
{
return IS_ENABLED(CONFIG_ARM64_PTR_AUTH) &&
(cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH_ARCH) ||
cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH_IMP_DEF));
}
static inline bool system_supports_generic_auth(void)
{
return IS_ENABLED(CONFIG_ARM64_PTR_AUTH) &&
(cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH_ARCH) ||
cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH_IMP_DEF));
}
static inline bool system_uses_irq_prio_masking(void)
{
return IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) &&
cpus_have_const_cap(ARM64_HAS_IRQ_PRIO_MASKING);
}
static inline bool system_has_prio_mask_debugging(void)
{
return IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) &&
system_uses_irq_prio_masking();
}
#define ARM64_BP_HARDEN_UNKNOWN -1
#define ARM64_BP_HARDEN_WA_NEEDED 0
#define ARM64_BP_HARDEN_NOT_REQUIRED 1
int get_spectre_v2_workaround_state(void);
#define ARM64_SSBD_UNKNOWN -1
#define ARM64_SSBD_FORCE_DISABLE 0
#define ARM64_SSBD_KERNEL 1
#define ARM64_SSBD_FORCE_ENABLE 2
#define ARM64_SSBD_MITIGATED 3
static inline int arm64_get_ssbd_state(void)
{
#ifdef CONFIG_ARM64_SSBD
extern int ssbd_state;
return ssbd_state;
#else
return ARM64_SSBD_UNKNOWN;
#endif
}
void arm64_set_ssbd_mitigation(bool state);
extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt);
static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
{
switch (parange) {
case 0: return 32;
case 1: return 36;
case 2: return 40;
case 3: return 42;
case 4: return 44;
case 5: return 48;
case 6: return 52;
/*
* A future PE could use a value unknown to the kernel.
* However, by the "D10.1.4 Principles of the ID scheme
* for fields in ID registers", ARM DDI 0487C.a, any new
* value is guaranteed to be higher than what we know already.
* As a safe limit, we return the limit supported by the kernel.
*/
default: return CONFIG_ARM64_PA_BITS;
}
}
#endif /* __ASSEMBLY__ */
#endif
