tree 8144508a6e57975c6ad9d5eca4301647e79224bb
parent 3b566b30b41401888ee0e8eb904a1e7a6693794b
author Yazen Ghannam <yazen.ghannam@amd.com> 1707881716 -0600
committer Borislav Petkov (AMD) <bp@alien8.de> 1708451775 +0100

RAS: Introduce a FRU memory poison manager

Memory errors are an expected occurrence on systems with high memory
density. Generally, errors within a small number of unique physical
locations are acceptable, based on manufacturer and/or admin policy.
During run time, memory with errors may be retired so it is no longer
used by the system. This is done in mm through page poisoning, and the
effect will remain until the system is restarted.

If a memory location is consistently faulty, then the same run time
error handling may occur in the next reboot cycle, leading to
terminating jobs due to that already known bad memory. This could be
prevented if information from the previous boot was not lost.

Some add-in cards with driver-managed memory have on-board persistent
storage. Their driver saves memory error information to the persistent
storage during run time. The information is then restored after reset,
and known bad memory will be retired before the hardware is used.
A running log of bad memory locations is kept across multiple resets.

A similar solution is desirable for CPUs. However, this solution should
leverage industry-standard components as much as possible, rather than
a bespoke platform driver.

Two components are needed: a record format and a persistent storage
interface.

Implement a new module to manage the record formats on persistent
storage. Use the requirements for an AMD MI300-based system to start.
Vendor- and platform-specific details can be abstracted later as needed.

  [ bp: Massage commit message and code, squash 30-ish more fixes from
    Yazen and me. ]

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Co-developed-by: <naveenkrishna.chatradhi@amd.com>
Signed-off-by: <naveenkrishna.chatradhi@amd.com>
Co-developed-by: <muralidhara.mk@amd.com>
Signed-off-by: <muralidhara.mk@amd.com>
Tested-by: <sathyapriya.k@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240214033516.1344948-3-yazen.ghannam@amd.com