firmware: smccc: Fix check for ARCH_SOC_ID not implemented
authorMichael Kelley <mikelley@microsoft.com>
Fri, 19 Nov 2021 23:39:01 +0000 (15:39 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 1 Dec 2021 08:19:04 +0000 (09:19 +0100)
commit6d9e8dabd46faa2fdf5cc3c78b493a63de994340
treed4655d95135282acce761facb3bc0bf288802002
parentbbd1683e795cec80acc2e5107c3d29b9c3f49297
firmware: smccc: Fix check for ARCH_SOC_ID not implemented

[ Upstream commit e95d8eaee21cd0d117d34125d4cdc97489c1ab82 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/firmware/smccc/soc_id.c