Re: [PATCH 1/2] lscpu-arm: Allow externally sourced model name.

On 7/11/2025 6:22 PM, Jeremy Linton wrote:
> Hi,
> 
> On 7/11/25 4:16 PM, Paul Benoit wrote:
>> When there isn't an entry for the model name in the id_part table(s),
>> attempt to get the machine name from /sys/bus/soc/devices/soc0/machine
>> to use as the model name.  This mechanism allows lscpu to use the
>> model/machine name provided via the ARM SMC support code rather than via
>> hard-coded lscpu tables.
> 
> Since this is suppose to be synced with the DMI data, and is sourced 
> from the firmware would it make more sense to replace the BIOS name with 
> it?

I was recently reminded that the SMC CC SOC_ID Name
(/sys/bus/soc/devices/soc0/machine) and BIOS name could be from 2
different organizations, and may not always resemble each other.

> 
> 
>>
>> This code was tested by removing the "Ampere-1a" entry from the
>> ampere-part table and verifying that lscpu displayed the correct machine
>> name obtained via the ARM SMC interface to Trusted Firmware.  The
>> "Ampere-1a" entry will be permanently removed by a separate patch.
>>
>> Signed-off-by: Paul Benoit <[email protected]>
>> ---
>>   sys-utils/lscpu-arm.c | 35 ++++++++++++++++++++++++++++++++---
>>   sys-utils/lscpu.h     |  1 +
>>   2 files changed, 33 insertions(+), 3 deletions(-)
>>
>> diff --git a/sys-utils/lscpu-arm.c b/sys-utils/lscpu-arm.c
>> index 8745599d4..a46106bcb 100644
>> --- a/sys-utils/lscpu-arm.c
>> +++ b/sys-utils/lscpu-arm.c
>> @@ -388,7 +388,10 @@ int is_arm(struct lscpu_cxt *cxt)
>>   static int arm_ids_decode(struct lscpu_cputype *ct)
>>   {
>>       int impl, part, j;
>> +    unsigned int i;
>>       const struct id_part *parts = NULL;
>> +    FILE *fd;
>> +    char machinename[BUFSIZ] = "";
>>       impl = parse_implementer_id(ct);
>>       if (impl <= 0)
>> @@ -406,11 +409,11 @@ static int arm_ids_decode(struct lscpu_cputype *ct)
>>       /* decode model */
>>       if (!parts)
>> -        goto done;
>> +        goto try_machinename;
>>       part = parse_model_id(ct);
>>       if (part <= 0)
>> -        goto done;
>> +        goto try_machinename;
>>       for (j = 0; parts[j].id != -1; j++) {
>>           if (parts[j].id == part) {
>> @@ -419,7 +422,33 @@ static int arm_ids_decode(struct lscpu_cputype *ct)
>>               break;
>>           }
>>       }
>> -done:
>> +
>> +try_machinename:
>> +
>> +    /*
>> +     * If the Model name was not found in the lscpu 'id_part' tables, 
>> see
>> +     * if there is a Machine name associated with the SOC.  This name 
>> may
>> +     * have been set via either SOC specific support code, or obtained
>> +     * via an ARM SMC CC call into Trusted Firmware.
>> +     */
>> +    if (!ct->modelname) {
>> +        fd = ul_path_fopen(NULL, "r", _PATH_SOC_MACHINENAME);
>> +        if (fd) {
>> +            if (!fgets(machinename, sizeof(machinename), fd))
>> +                machinename[0] = '\0';
>> +            fclose(fd);
>> +
>> +            /* Replace newline with string terminator */
>> +            for (i = 0; i < strlen(machinename); i++) {
>> +                if (machinename[i] == '\n')
>> +                    machinename[i] = '\0';
>> +            }
>> +
>> +            if (strnlen(machinename, sizeof(machinename)))
>> +                ct->modelname = xstrdup(machinename);
>> +        }
>> +    }
>> +
>>       return 0;
>>   }
>> diff --git a/sys-utils/lscpu.h b/sys-utils/lscpu.h
>> index bd7b64cc5..581602f70 100644
>> --- a/sys-utils/lscpu.h
>> +++ b/sys-utils/lscpu.h
>> @@ -46,6 +46,7 @@ UL_DEBUG_DECLARE_MASK(lscpu);
>>   #define _PATH_SYS_NODE        _PATH_SYS_SYSTEM "/node"
>>   #define _PATH_SYS_DMI        "/sys/firmware/dmi/tables/DMI"
>>   #define _PATH_ACPI_PPTT        "/sys/firmware/acpi/tables/PPTT"
>> +#define _PATH_SOC_MACHINENAME    "/sys/bus/soc/devices/soc0/machine"
>>   struct lscpu_cache {
>>       int        id;        /* unique identifier */
>