Re: [PATCH 2/6] ArmPkg: Correct return value of "SMCCC_ARCH_SOC_ID" Function ID call

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Nhi,

Thank you for this fix.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

On 23/08/2022 11:59 am, Nhi Pham wrote:
> From: Minh Nguyen <minhn@amperecomputing.com>
>
> According to "SMC Calling Convention" specification, section 7.4,
> return value of Arm Architecture Calls is stored at first argument of
> SMC aguments (ARM_SMC_ARGS). This value can be negative values indicating
> error or positive values (including zero) indicating success. Positive
> value would contain information of respective Function ID (Section 7.3.4
> and 7.4.4).
>
> For that reason, "SMCCC_VERSION" and "SMCCC_ARCH_FEATURES"
> Function ID calls read return value from "SmcCallStatus" variable
> (Args.Arg0 - first argument of SMC call). But "SMCCC_ARCH_SOC_ID"
> Function ID call is reading return value from "SmcParam" variable
> (Args.Arg1 - second argument of SMC call) so it leads to unexpected
> results of "Jep106Code" and "SocRevision". This patch is to correct it.
>
> Signed-off-by: Nhi Pham <nhi@os.amperecomputing.com>
> ---
>   ArmPkg/Universal/Smbios/ProcessorSubClassDxe/SmbiosProcessorArmCommon.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/ArmPkg/Universal/Smbios/ProcessorSubClassDxe/SmbiosProcessorArmCommon.c b/ArmPkg/Universal/Smbios/ProcessorSubClassDxe/SmbiosProcessorArmCommon.c
> index e0010a40e489..b961be213358 100644
> --- a/ArmPkg/Universal/Smbios/ProcessorSubClassDxe/SmbiosProcessorArmCommon.c
> +++ b/ArmPkg/Universal/Smbios/ProcessorSubClassDxe/SmbiosProcessorArmCommon.c
> @@ -2,7 +2,7 @@
>     Functions for processor information common to ARM and AARCH64.
>
>   
>
>     Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
>
> -  Copyright (c) 2021, Ampere Computing LLC. All rights reserved.<BR>
>
> +  Copyright (c) 2021 - 2022, Ampere Computing LLC. All rights reserved.<BR>
>
>   
>
>     SPDX-License-Identifier: BSD-2-Clause-Patent
>
>   
>
> @@ -131,7 +131,7 @@ SmbiosGetSmcArm64SocId (
>     SmcCallStatus = ArmCallSmc1 (SMCCC_ARCH_SOC_ID, &SmcParam, NULL, NULL);
>
>   
>
>     if (SmcCallStatus >= 0) {
>
> -    *Jep106Code = (INT32)SmcParam;
>
> +    *Jep106Code = SmcCallStatus;
>
>     } else {
>
>       Status = EFI_UNSUPPORTED;
>
>     }
>
> @@ -140,7 +140,7 @@ SmbiosGetSmcArm64SocId (
>     SmcCallStatus = ArmCallSmc1 (SMCCC_ARCH_SOC_ID, &SmcParam, NULL, NULL);
>
>   
>
>     if (SmcCallStatus >= 0) {
>
> -    *SocRevision = (INT32)SmcParam;
>
> +    *SocRevision = SmcCallStatus;
>
>     } else {
>
>       Status = EFI_UNSUPPORTED;
>
>     }
>