Merge pull request #1033 from davidcunado-arm/dc/psci_flush
Address edge case for stale PSCI CPU data in cache
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commit
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@ -64,7 +64,20 @@ int psci_cpu_on_start(u_register_t target_cpu,
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/*
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/*
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* Generic management: Ensure that the cpu is off to be
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* Generic management: Ensure that the cpu is off to be
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* turned on.
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* turned on.
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* Perform cache maintanence ahead of reading the target CPU state to
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* ensure that the data is not stale.
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* There is a theoretical edge case where the cache may contain stale
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* data for the target CPU data - this can occur under the following
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* conditions:
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* - the target CPU is in another cluster from the current
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* - the target CPU was the last CPU to shutdown on its cluster
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* - the cluster was removed from coherency as part of the CPU shutdown
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*
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* In this case the cache maintenace that was performed as part of the
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* target CPUs shutdown was not seen by the current CPU's cluster. And
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* so the cache may contain stale data for the target CPU.
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*/
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*/
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flush_cpu_data_by_index(target_idx, psci_svc_cpu_data.aff_info_state);
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rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx));
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rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx));
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if (rc != PSCI_E_SUCCESS)
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if (rc != PSCI_E_SUCCESS)
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goto exit;
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goto exit;
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