Subject: [PATCH] firmware: qcom_scm: Mark get_wq_ctx() as atomic call

From: Murali Nalajala <[email protected]>

Currently get_wq_ctx() is wrongly configured as a standard call.
Here get_wq_ctx() must be an atomic call and can't be a standard
SMC call because get_wq_ctx() should not sleep again. This
situation lead to a deadlock. Hence mark get_wq_ctx() as
atomic call.

Fixes: 6bf325992236 ("firmware: qcom: scm: Add wait-queue handling logic")
Cc: [email protected]
Signed-off-by: Murali Nalajala <[email protected]>
Signed-off-by: Unnathi Chalicheemala <[email protected]>
---
drivers/firmware/qcom/qcom_scm-smc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/qcom/qcom_scm-smc.c b/drivers/firmware/qcom/qcom_scm-smc.c
index 16cf88acfa8e..0a2a2c794d0e 100644
--- a/drivers/firmware/qcom/qcom_scm-smc.c
+++ b/drivers/firmware/qcom/qcom_scm-smc.c
@@ -71,7 +71,7 @@ int scm_get_wq_ctx(u32 *wq_ctx, u32 *flags, u32 *more_pending)
struct arm_smccc_res get_wq_res;
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,
SCM_SMC_FNID(QCOM_SCM_SVC_WAITQ, QCOM_SCM_WAITQ_GET_WQ_CTX));


---
base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670
change-id: 20240611-get_wq_ctx_atomic-f5e9fdcb20c7

Best regards,
--
Unnathi Chalicheemala <[email protected]>




2024-06-13 07:39:33

by Konrad Dybcio

[permalink] [raw]
Subject: Re: [PATCH] firmware: qcom_scm: Mark get_wq_ctx() as atomic call



On 6/11/24 20:27, Unnathi Chalicheemala via B4 Relay wrote:
> From: Murali Nalajala <[email protected]>
>
> Currently get_wq_ctx() is wrongly configured as a standard call.
> Here get_wq_ctx() must be an atomic call and can't be a standard
> SMC call because get_wq_ctx() should not sleep again. This
> situation lead to a deadlock. Hence mark get_wq_ctx() as
> atomic call.

That's quite a word salad.. could you try to make it clearer what
you're trying to achieve?

Konrad