From 95e747c3c60d22901c9c9ac9473f240336a42341 Mon Sep 17 00:00:00 2001 From: Kathiravan Thirumoorthy Date: Mon, 25 Sep 2023 13:59:22 +0530 Subject: [PATCH] firmware: qcom_scm: use 64-bit calling convention only when client is 64-bit commit 3337a6fea25370d3d244ec6bb38c71ee86fcf837 upstream. Per the "SMC calling convention specification", the 64-bit calling convention can only be used when the client is 64-bit. Whereas the 32-bit calling convention can be used by either a 32-bit or a 64-bit client. Currently during SCM probe, irrespective of the client, 64-bit calling convention is made, which is incorrect and may lead to the undefined behaviour when the client is 32-bit. Let's fix it. Cc: stable@vger.kernel.org Fixes: 9a434cee773a ("firmware: qcom_scm: Dynamically support SMCCC and legacy conventions") Reviewed-By: Elliot Berman Signed-off-by: Kathiravan Thirumoorthy Link: https://lore.kernel.org/r/20230925-scm-v3-1-8790dff6a749@quicinc.com Signed-off-by: Bjorn Andersson Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/qcom_scm.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index 51eb85354c05..58f1a86065dc 100644 --- a/drivers/firmware/qcom_scm.c +++ b/drivers/firmware/qcom_scm.c @@ -164,6 +164,12 @@ static enum qcom_scm_convention __get_convention(void) if (likely(qcom_scm_convention != SMC_CONVENTION_UNKNOWN)) return qcom_scm_convention; + /* + * Per the "SMC calling convention specification", the 64-bit calling + * convention can only be used when the client is 64-bit, otherwise + * system will encounter the undefined behaviour. + */ +#if IS_ENABLED(CONFIG_ARM64) /* * Device isn't required as there is only one argument - no device * needed to dma_map_single to secure world @@ -184,6 +190,7 @@ static enum qcom_scm_convention __get_convention(void) forced = true; goto found; } +#endif probed_convention = SMC_CONVENTION_ARM_32; ret = __scm_smc_call(NULL, &desc, probed_convention, &res, true);