From: Michael Kelley mikelley@microsoft.com
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=...
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[ 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 Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- 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; }