SCM driver looks messy in terms of handling concurrency of probe. The
driver exports interface which is guarded by global '__scm' variable
but:
1. Lacks proper read barrier (commit adding write barriers mixed up
READ_ONCE with a read barrier).
2. Lacks barriers or checks for '__scm' in multiple places.
3. Lacks probe error cleanup.
I fixed here few visible things, but this was not tested extensively. I
tried only SM8450.
ARM32 and SC8280xp/X1E platforms would be useful for testing as well.
All the issues here are non-urgent, IOW, they were here for some time
(v6.10-rc1 and earlier).
Best regards,
Krzysztof
---
Krzysztof Kozlowski (6):
firmware: qcom: scm: Fix missing read barrier in qcom_scm_is_available()
firmware: qcom: scm: Fix missing read barrier in qcom_scm_get_tzmem_pool()
firmware: qcom: scm: Handle various probe ordering for qcom_scm_assign_mem()
[RFC/RFT] firmware: qcom: scm: Cleanup global '__scm' on probe failures
firmware: qcom: scm: smc: Handle missing SCM device
firmware: qcom: scm: smc: Narrow 'mempool' variable scope
drivers/firmware/qcom/qcom_scm-smc.c | 6 +++-
drivers/firmware/qcom/qcom_scm.c | 55 +++++++++++++++++++++++++-----------
2 files changed, 44 insertions(+), 17 deletions(-)
---
base-commit: 414c97c966b69e4a6ea7b32970fa166b2f9b9ef0
change-id: 20241119-qcom-scm-missing-barriers-and-all-sort-of-srap-a25d59074882
Best regards,
--
Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
