On Tue, Nov 19, 2024 at 07:33:16PM +0100, Krzysztof Kozlowski wrote: > 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. ARM32 devices are present in the lab. > > 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> > -- With best wishes Dmitry
