kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity

platform/x86/amd/hsmp: Serialize per-socket metric table reads with a mutex

Browse source 
HSMP_GET_METRIC_TABLE makes the firmware refill a shared per-socket metric
DRAM region, which hsmp_metric_tbl_read() then copies out with
memcpy_fromio(). Two concurrent readers of the metrics_bin sysfs attribute
on the same socket can race: one can trigger a fresh fill while the other
is mid-copy and return a torn snapshot. (The hwmon path does not touch
this region; it only issues power messages via hsmp_send_message().)

Embed a struct mutex metric_read_lock in each hsmp_socket and hold it
across the fill-and-copy in hsmp_metric_tbl_read(). Add
hsmp_init_metric_read_locks() and hsmp_destroy_metric_read_locks(), which
take only struct hsmp_plat_device and iterate pdev->sock[] over
pdev->num_sockets so the caller cannot pass a count that disagrees with the
array.

Wire them into both front-ends' probe and teardown paths so the mutex is
always initialized before metrics_bin is exposed: the platform driver and
the ACPI driver both drive hsmp_metric_tbl_read() through the same 0444
metrics_bin attribute. Doing this in one patch avoids a bisection point
where an ACPI read would lock an uninitialized mutex.

Signed-off-by: Muralidhara M K <muralidhara.mk@amd.com>
Link: https://patch.msgid.link/20260723094656.3806028-4-muralidhara.mk@amd.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Muralidhara M K 2026-07-23 15:16:53 +05:30 • committed by Ilpo Järvinen
commit 8da4fedd5d
No known key found for this signature in database
GPG key ID: 59AC4F6153E5CE31
4 changed files with 39 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files