6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kathiravan Thirumoorthy <quic_kathirav@xxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Fixes: 9a434cee773a ("firmware: qcom_scm: Dynamically support SMCCC and legacy conventions")
Reviewed-By: Elliot Berman <quic_eberman@xxxxxxxxxxx>
Signed-off-by: Kathiravan Thirumoorthy <quic_kathirav@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230925-scm-v3-1-8790dff6a749@xxxxxxxxxxx
Signed-off-by: Bjorn Andersson <andersson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/qcom_scm.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -168,6 +168,12 @@ static enum qcom_scm_convention __get_co
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
*/
@@ -187,6 +193,7 @@ static enum qcom_scm_convention __get_co
forced = true;
goto found;
}
+#endif
probed_convention = SMC_CONVENTION_ARM_32;
ret = __scm_smc_call(NULL, &desc, probed_convention, &res, true);
