diff options
| -rw-r--r-- | Documentation/arm64/silicon-errata.rst | 3 | ||||
| -rw-r--r-- | arch/arm64/Kconfig | 19 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 7 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/pgtable.c | 14 | ||||
| -rw-r--r-- | arch/arm64/tools/cpucaps | 1 |
5 files changed, 41 insertions, 3 deletions
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index 9e311bc43e05..cd46e2b20a81 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -52,6 +52,9 @@ stable kernels. | Allwinner | A64/R18 | UNKNOWN1 | SUN50I_ERRATUM_UNKNOWN1 | +----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ +| Ampere | AmpereOne | AC03_CPU_38 | AMPERE_ERRATUM_AC03_CPU_38 | ++----------------+-----------------+-----------------+-----------------------------+ ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2457168 | ARM64_ERRATUM_2457168 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2064142 | ARM64_ERRATUM_2064142 | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1201d25a8a4..0987c637fbf2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -406,6 +406,25 @@ menu "Kernel Features" menu "ARM errata workarounds via the alternatives framework" +config AMPERE_ERRATUM_AC03_CPU_38 + bool "AmpereOne: AC03_CPU_38: Certain bits in the Virtualization Translation Control Register and Translation Control Registers do not follow RES0 semantics" + default y + help + This option adds an alternative code sequence to work around Ampere + erratum AC03_CPU_38 on AmpereOne. + + The affected design reports FEAT_HAFDBS as not implemented in + ID_AA64MMFR1_EL1.HAFDBS, but (V)TCR_ELx.{HA,HD} are not RES0 + as required by the architecture. The unadvertised HAFDBS + implementation suffers from an additional erratum where hardware + A/D updates can occur after a PTE has been marked invalid. + + The workaround forces KVM to explicitly set VTCR_EL2.HA to 0, + which avoids enabling unadvertised hardware Access Flag management + at stage-2. + + If unsure, say Y. + config ARM64_WORKAROUND_CLEAN_CACHE bool diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 307faa2b4395..be66e94a21bd 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -730,6 +730,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .cpu_enable = cpu_clear_bf16_from_user_emulation, }, #endif +#ifdef CONFIG_AMPERE_ERRATUM_AC03_CPU_38 + { + .desc = "AmpereOne erratum AC03_CPU_38", + .capability = ARM64_WORKAROUND_AMPERE_AC03_CPU_38, + ERRATA_MIDR_ALL_VERSIONS(MIDR_AMPERE1), + }, +#endif { } }; diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 5282cb9ca4cf..32d92ce4bae5 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -611,10 +611,18 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift) #ifdef CONFIG_ARM64_HW_AFDBM /* * Enable the Hardware Access Flag management, unconditionally - * on all CPUs. The features is RES0 on CPUs without the support - * and must be ignored by the CPUs. + * on all CPUs. In systems that have asymmetric support for the feature + * this allows KVM to leverage hardware support on the subset of cores + * that implement the feature. + * + * The architecture requires VTCR_EL2.HA to be RES0 (thus ignored by + * hardware) on implementations that do not advertise support for the + * feature. As such, setting HA unconditionally is safe, unless you + * happen to be running on a design that has unadvertised support for + * HAFDBS. Here be dragons. */ - vtcr |= VTCR_EL2_HA; + if (!cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38)) + vtcr |= VTCR_EL2_HA; #endif /* CONFIG_ARM64_HW_AFDBM */ /* Set the vmid bits */ diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 40ba95472594..9f9a2d6652eb 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -77,6 +77,7 @@ WORKAROUND_2077057 WORKAROUND_2457168 WORKAROUND_2645198 WORKAROUND_2658417 +WORKAROUND_AMPERE_AC03_CPU_38 WORKAROUND_TRBE_OVERWRITE_FILL_MODE WORKAROUND_TSB_FLUSH_FAILURE WORKAROUND_TRBE_WRITE_OUT_OF_RANGE |