6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mukesh Ojha quic_mojha@quicinc.com
[ 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 quic_mojha@quicinc.com Link: https://lore.kernel.org/r/1711034642-22860-4-git-send-email-quic_mojha@quici... Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 69831f1d91e3f..ff7c155239e31 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) {