From 0cac39347f4ebea4d44e8191c0efb06ad7e302bf Mon Sep 17 00:00:00 2001 From: Mukesh Ojha Date: Thu, 21 Mar 2024 20:54:02 +0530 Subject: [PATCH] firmware: qcom: scm: Fix __scm and waitq completion variable initialization [ Upstream commit 2e4955167ec5c04534cebea9e8273a907e7a75e1 ] It is possible qcom_scm_is_available() gives wrong indication that if __scm is initialized while __scm->dev is not and similar issue is also possible with __scm->waitq_comp. Fix this appropriately by the use of release barrier and read barrier that will make sure if __scm is initialized so, is all of its field variable. Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver") Fixes: 6bf325992236 ("firmware: qcom: scm: Add wait-queue handling logic") Signed-off-by: Mukesh Ojha Link: https://lore.kernel.org/r/1711034642-22860-4-git-send-email-quic_mojha@quicinc.com Signed-off-by: Bjorn Andersson Signed-off-by: Sasha Levin --- drivers/firmware/qcom_scm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index 69831f1d91e3..ff7c155239e3 100644 --- a/drivers/firmware/qcom_scm.c +++ b/drivers/firmware/qcom_scm.c @@ -1333,7 +1333,7 @@ static int qcom_scm_find_dload_address(struct device *dev, u64 *addr) */ bool qcom_scm_is_available(void) { - return !!__scm; + return !!READ_ONCE(__scm); } EXPORT_SYMBOL_GPL(qcom_scm_is_available); @@ -1414,10 +1414,12 @@ static int qcom_scm_probe(struct platform_device *pdev) if (!scm) return -ENOMEM; + scm->dev = &pdev->dev; ret = qcom_scm_find_dload_address(&pdev->dev, &scm->dload_mode_addr); if (ret < 0) return ret; + init_completion(&scm->waitq_comp); mutex_init(&scm->scm_bw_lock); scm->path = devm_of_icc_get(&pdev->dev, NULL); @@ -1449,10 +1451,8 @@ static int qcom_scm_probe(struct platform_device *pdev) if (ret) return ret; - __scm = scm; - __scm->dev = &pdev->dev; - - init_completion(&__scm->waitq_comp); + /* Let all above stores be available after this */ + smp_store_release(&__scm, scm); irq = platform_get_irq_optional(pdev, 0); if (irq < 0) {