linux-kernel - [PATCH 5.15 107/179] firmware: smccc: Fix check for ARCH_SOC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211129181722.465030389@linuxfoundation.org>
Date:   Mon, 29 Nov 2021 19:18:21 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Michael Kelley <mikelley@...rosoft.com>,
        Sudeep Holla <sudeep.holla@....com>,
        Arnd Bergmann <arnd@...db.de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 107/179] firmware: smccc: Fix check for ARCH_SOC_ID not implemented

From: Michael Kelley <mikelley@...rosoft.com>

[ 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@...rosoft.com>
Reviewed-by: Sudeep Holla <sudeep.holla@....com>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 581aa5e9b0778..dd7c3d5e8b0bb 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;
 	}
-- 
2.33.0