On 10/9/2023 4:53 PM, Ilpo Järvinen wrote:
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On Mon, 9 Oct 2023, Hegde, Suma wrote:
On 10/6/2023 6:51 PM, Ilpo Järvinen wrote:
On Thu, 5 Oct 2023, Suma Hegde wrote:
AMD MI300 MCM provides GET_METRICS_TABLE message to retrieve
all the system management information from SMU.
The metrics table is made available as hexadecimal sysfs binary file
under per socket sysfs directory created at
/sys/devices/platform/amd_hsmp/socket%d/metrics_bin
Metrics table definitions will be documented as part of Public PPR.
The same is defined in the amd_hsmp.h header.
Signed-off-by: Suma Hegde <suma.hegde@xxxxxxx>
Reviewed-by: Naveen Krishna Chatradhi <nchatrad@xxxxxxx>
+static int hsmp_create_sysfs_interface(void)
+{
+ const struct attribute_group **hsmp_attr_grps;
+ struct bin_attribute **hsmp_bin_attrs;
+ struct attribute_group *attr_grp;
+ int ret;
+ u8 i;
+
+ hsmp_attr_grps = devm_kzalloc(plat_dev.dev, sizeof(struct
attribute_group *) *
+ (plat_dev.num_sockets + 1),
GFP_KERNEL);
+ if (!hsmp_attr_grps)
+ return -ENOMEM;
+
+ /* Create a sysfs directory for each socket */
+ for (i = 0; i < plat_dev.num_sockets; i++) {
The change for i to u8 seems not very wise given num_sockets still is u16
as it can turn this into an infinite loop.
Hi Ilpo,
amd_nb_num() API which we use to identify the number of sockets on a node
returns u16. So, we used u16 for plat_dev.num_sockets.
u8 should be enough, as present AMD processors support upto 8 sockets on a
node.
I wasn't expecting it to fail at the moment, I just don't want to leave a
silent trap for the future.
Coming to the warning raised:
We have defined, HSMP_ATTR_GRP_NAME_SIZE as 10bytes, 6 chars for 'socket', 3
chars for 3digits (socket index) and a null terminator.
Socket index may not need more than 3 digits in the foreseeable future. How
about, we declare i as u16 and typecast it as (u8) in the snprintf.
int ret;
- u8 i;
+ u16 i;
hsmp_attr_grps = devm_kzalloc(plat_dev.dev, sizeof(struct
attribute_group *) *
(plat_dev.num_sockets + 1), GFP_KERNEL); @@
-449,7 +449,7 @@ static int hsmp_create_sysfs_interface(void)
if (!attr_grp)
return -ENOMEM;
- snprintf(plat_dev.sock[i].name, HSMP_ATTR_GRP_NAME_SIZE, "socket%u",
i);
+ snprintf(plat_dev.sock[i].name, HSMP_ATTR_GRP_NAME_SIZE,
+ "socket%u", (u8)i);
attr_grp->name = plat_dev.sock[i].name;
This is similarly trappy as it truncates i if num_sockets is > 255.
I suggest you just put this into start of the function:
/* String formatting is currently limited to u8 sockets */
if (WARN_ON(plat_dev.num_sockets > U8_MAX))
return -ERANGE;
to catch the too many sockets case if it is ever going to occur.
And explain in the changelog that u8 is enough for foreseeable future
and the string formatting triggers a warning if unnecessarily large type
is passed to snprintf().
Ok Ilpo, I will add this WARN_ON and send v5 patch set.
--
i.
