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Merge pull request #1033 from davidcunado-arm/dc/psci_flush 

Address edge case for stale PSCI CPU data in cache
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davidcunado-arm 2017-07-31 08:45:44 +01:00 committed by GitHub
parent 401e4911bc 71341d2366
commit d9f18155e0
1 changed files with 13 additions and 0 deletions
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13
lib/psci/psci_on.c
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@ -64,7 +64,20 @@ int psci_cpu_on_start(u_register_t target_cpu,
/*
* Generic management: Ensure that the cpu is off to be
* turned on.
* Perform cache maintanence ahead of reading the target CPU state to
* ensure that the data is not stale.
* There is a theoretical edge case where the cache may contain stale
* data for the target CPU data - this can occur under the following
* conditions:
* - the target CPU is in another cluster from the current
* - the target CPU was the last CPU to shutdown on its cluster
* - the cluster was removed from coherency as part of the CPU shutdown
*
* In this case the cache maintenace that was performed as part of the
* target CPUs shutdown was not seen by the current CPU's cluster. And
* so the cache may contain stale data for the target CPU.
*/
flush_cpu_data_by_index(target_idx, psci_svc_cpu_data.aff_info_state);
rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx));
if (rc != PSCI_E_SUCCESS)
goto exit;