firmware: smccc: Fix check for ARCH_SOC_ID not implemented

stable inclusion
from stable-v5.10.83
commit 6d9e8dabd46faa2fdf5cc3c78b493a63de994340
bugzilla: 185879 https://gitee.com/openeuler/kernel/issues/I4QUVG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6d9e8dabd46faa2fdf5cc3c78b493a63de994340

--------------------------------

[ Upstream commit e95d8eae ]

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: 821b67fa ("firmware: smccc: Add ARCH_SOC_ID support")
Signed-off-by: NMichael Kelley <mikelley@microsoft.com>
Reviewed-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

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;
 	}