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firmware: qcom: scm: Mark get_wq_ctx() as atomic call

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Currently get_wq_ctx() is wrongly configured as a standard call. When two
SMC calls are in sleep and one SMC wakes up, it calls get_wq_ctx() to
resume the corresponding sleeping thread. But if get_wq_ctx() is
interrupted, goes to sleep and another SMC call is waiting to be allocated
a waitq context, it leads to a deadlock.

To avoid this get_wq_ctx() must be an atomic call and can't be a standard
SMC call. Hence mark get_wq_ctx() as a fast call.

Fixes: 6bf3259922 ("firmware: qcom: scm: Add wait-queue handling logic")
Cc: stable@vger.kernel.org
Signed-off-by: Murali Nalajala <quic_mnalajal@quicinc.com>
Signed-off-by: Unnathi Chalicheemala <quic_uchalich@quicinc.com>
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Link: https://lore.kernel.org/r/20240814223244.40081-1-quic_uchalich@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
This commit is contained in:
Murali Nalajala 2024-08-14 15:32:44 -07:00 committed by Bjorn Andersson
parent fce6a1eefb
commit 9960085a3a
1 changed files with 1 additions and 1 deletions
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2
drivers/firmware/qcom/qcom_scm-smc.c
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@ -73,7 +73,7 @@ int scm_get_wq_ctx(u32 *wq_ctx, u32 *flags, u32 *more_pending)
struct arm_smccc_res get_wq_res; struct arm_smccc_res get_wq_res;
struct arm_smccc_args get_wq_ctx = {0}; struct arm_smccc_args get_wq_ctx = {0};
get_wq_ctx.args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, get_wq_ctx.args[0] = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,
ARM_SMCCC_SMC_64, ARM_SMCCC_OWNER_SIP, ARM_SMCCC_SMC_64, ARM_SMCCC_OWNER_SIP,
SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_GET_WQ_CTX)); SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_GET_WQ_CTX));