From e95d8eaee21cd0d117d34125d4cdc97489c1ab82 Mon Sep 17 00:00:00 2001
From: Michael Kelley <mikelley@microsoft.com>
Date: Fri, 19 Nov 2021 15:39:01 -0800
Subject: [PATCH] firmware: smccc: Fix check for ARCH_SOC_ID not implemented
Git-commit: e95d8eaee21cd0d117d34125d4cdc97489c1ab82
Patch-mainline: v5.16-rc3
References: git-fixes
The ARCH_FEATURES function ID is a 32-bit SMC call, which returns
a 32-bit result per the SMCCC spec. Current code is doing a 64-bit
comparison against -1 (SMCCC_RET_NOT_SUPPORTED) to detect that the
feature is unimplemented. That check doesn't work in a Hyper-V VM,
where the upper 32-bits are zero as allowed by the spec.
Cast the result as an 'int' so the comparison works. The change also
makes the code consistent with other similar checks in this file.
Fixes: 821b67fa4639 ("firmware: smccc: Add ARCH_SOC_ID support")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/firmware/smccc/soc_id.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/smccc/soc_id.c b/drivers/firmware/smccc/soc_id.c
index 581aa5e9b077..dd7c3d5e8b0b 100644
--- a/drivers/firmware/smccc/soc_id.c
+++ b/drivers/firmware/smccc/soc_id.c
@@ -50,7 +50,7 @@ static int __init smccc_soc_init(void)
arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_SOC_ID, &res);
- if (res.a0 == SMCCC_RET_NOT_SUPPORTED) {
+ if ((int)res.a0 == SMCCC_RET_NOT_SUPPORTED) {
pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
return 0;
}
--
2.31.1