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arm64: capabilities: Add support for checks based on a list of MIDRs

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[ Upstream commit be5b299830c63ed76e0357473c4218c85fb388b3 ]

Add helpers for detecting an errata on list of midr ranges
of affected CPUs, with the same work around.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[ardb: add Cortex-A35 to kpti_safe_list[] as well]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Suzuki K Poulose 2022-04-06 17:45:14 +01:00 committed by Greg Kroah-Hartman
parent c771d4ceeb
commit c6815504d9
4 changed files with 58 additions and 35 deletions
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1
arch/arm64/include/asm/cpufeature.h
View File

@ -233,6 +233,7 @@ struct arm64_cpu_capabilities {
struct midr_range midr_range;
};
const struct midr_range *midr_range_list;
struct { /* Feature register checking */
u32 sys_reg;
u8 field_pos;

9
arch/arm64/include/asm/cputype.h
View File

@ -143,6 +143,15 @@ static inline bool is_midr_in_range(u32 midr, struct midr_range const *range)
range->rv_min, range->rv_max);
}
static inline bool
is_midr_in_range_list(u32 midr, struct midr_range const *ranges)
{
while (ranges->model)
if (is_midr_in_range(midr, ranges++))
return true;
return false;
}
/*
* The CPU ID never changes at run time, so we might as well tell the
* compiler that it's constant. Use this function to read the CPU ID

62
arch/arm64/kernel/cpu_errata.c
View File

@ -33,6 +33,14 @@ is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
return is_midr_in_range(midr, &entry->midr_range);
}
static bool __maybe_unused
is_affected_midr_range_list(const struct arm64_cpu_capabilities *entry,
int scope)
{
WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
return is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list);
}
static bool
has_mismatched_cache_type(const struct arm64_cpu_capabilities *entry,
int scope)
@ -383,6 +391,10 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \
CAP_MIDR_RANGE(model, v_min, r_min, v_max, r_max)
#define CAP_MIDR_RANGE_LIST(list) \
.matches = is_affected_midr_range_list, \
.midr_range_list = list
/* Errata affecting a range of revisions of given model variant */
#define ERRATA_MIDR_REV_RANGE(m, var, r_min, r_max) \
ERRATA_MIDR_RANGE(m, var, r_min, var, r_max)
@ -396,6 +408,29 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \
CAP_MIDR_ALL_VERSIONS(model)
/* Errata affecting a list of midr ranges, with same work around */
#define ERRATA_MIDR_RANGE_LIST(midr_list) \
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \
CAP_MIDR_RANGE_LIST(midr_list)
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
/*
* List of CPUs where we need to issue a psci call to
* harden the branch predictor.
*/
static const struct midr_range arm64_bp_harden_smccc_cpus[] = {
MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
{},
};
#endif
const struct arm64_cpu_capabilities arm64_errata[] = {
#if defined(CONFIG_ARM64_ERRATUM_826319) || \
defined(CONFIG_ARM64_ERRATUM_827319) || \
@ -486,32 +521,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
.cpu_enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
.cpu_enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
.cpu_enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
.cpu_enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
.cpu_enable = enable_smccc_arch_workaround_1,
},
{
.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
ERRATA_MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
ERRATA_MIDR_RANGE_LIST(arm64_bp_harden_smccc_cpus),
.cpu_enable = enable_smccc_arch_workaround_1,
},
#endif

21
arch/arm64/kernel/cpufeature.c
View File

@ -767,6 +767,17 @@ 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 __unused)
{
/* 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),
};
char const *str = "command line option";
u64 pfr0 = read_system_reg(SYS_ID_AA64PFR0_EL1);
@ -792,16 +803,8 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
return true;
/* Don't force KPTI for CPUs that are not vulnerable */
switch (read_cpuid_id() & MIDR_CPU_MODEL_MASK) {
case MIDR_CAVIUM_THUNDERX2:
case MIDR_BRCM_VULCAN:
case MIDR_CORTEX_A53:
case MIDR_CORTEX_A55:
case MIDR_CORTEX_A57:
case MIDR_CORTEX_A72:
case MIDR_CORTEX_A73:
if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))
return false;
}
/* Defer to CPU feature registers */
return !cpuid_feature_extract_unsigned_field(pfr0,