[PATCH v13 0/2] ACPI: Add support for ACPI RAS2 feature table

shiju.jose
2025-11-21T18:28:45Z

From: Shiju Jose <shiju.jose@huawei.com>

Add support for ACPI RAS2 feature table (RAS2) defined in the
ACPI 6.5 specification, section 5.2.21 and RAS2 HW based memory
scrubbing feature.

ACPI RAS2 patches were part of the EDAC series [1].

The code is based on linux.git v6.18-rc5 [2].

1. https://lore.kernel.org/linux-cxl/20250212143654.1893-1-shiju.jose@huawei.com/
2. https://github.com/torvalds/linux.git

Changes
=======
v12 -> v13:
1. Fixed some bugs reported and changes wanted by Borislav.
https://lore.kernel.org/all/20250910192707.GAaMHRCxWx37XitN3t@fat_crate.local/

2. Tried modifying the patch header as commented by Borislav.

3. Fixed a bug reported by Yazen.
https://lore.kernel.org/all/20250909162434.GB11602@yaz-khff2.amd.com/

4. Changed setting 'Requested Address Range' for GET_PATROL_PARAMETERS
command to meet the requirements from Daniel for Ampere Computing
platform.
https://lore.kernel.org/all/7a211c5c-174c-438b-9a98-fd47b057ea4a@os.amperecomputing.com/

5. In RAS2 driver, removed support for scrub control attributes 'addr' and
'size' for the time being with the expectation that a firmware will do
the full node demand scrubbing and may enable these attributes in the
future.

6. Add 'enable_demand' attribute to the EDAC scrub interface to start/stop
the demand scrub, which is used for the RAS2 demand scrub control.

v11 -> v12:
1. Modified logic for finding the lowest contiguous phy memory addr range for
NUMA domain using node_start_pfn() and node_spanned_pages() according to the
feedback from Mike Rapoport in v11.
https://lore.kernel.org/all/aKsIlFTkBsAF5sqD@kernel.org/

2. Rebase to 6.17-rc4.

v10 -> v11:
1. Simplified code by removing workarounds previously added to support
non-compliant case of single PCC channel shared across all proximity
domains (which is no longer required).
https://lore.kernel.org/all/f5b28977-0b80-4c39-929b-cf02ab1efb97@os.amperecomputing.com/

2. Fix for the comments from Borislav (Thanks).
https://lore.kernel.org/all/20250811152805.GQaJoMBecC4DSDtTAu@fat_crate.local/

3. Rebase to 6.17-rc1.

v9 -> v10:
1. Use pcc_chan->shmem instead of
acpi_os_ioremap(pcc_chan->shmem_base_addr,...) as it was
acpi_os_ioremap internally by the PCC driver to pcc_chan->shmem.

2. Changes required for the Ampere Computing system where uses a single
PCC channel for RAS2 memory features across all NUMA domains. Based on the
requirements from by Daniel on V9
https://lore.kernel.org/all/547ed8fb-d6b7-4b6b-a38b-bf13223971b1@os.amperecomputing.com/
and discussion with Jonathan.
2.1 Add node_to_range lookup facility to numa_memblks. This is to retrieve the lowest
physical continuous memory range of the memory associated with a NUMA domain.
2.2. Set requested addr range to the memory region's base addr and size
while send RAS2 cmd GET_PATROL_PARAMETER
in functions ras2_update_patrol_scrub_params_cache() &
ras2_get_patrol_scrub_running().
2.3. Split struct ras2_mem_ctx into struct ras2_mem_ctx_hdr and struct ras2_pxm_domain
to support cases, uses a single PCC channel for RAS2 scrubbers across all NUMA
domains and PCC channel per RAS2 scrub instance. Provided ACPI spec define single
memory scrub per NUMA domain.
2.4. EDAC feature sysfs folder for RAS2 changed from "acpi_ras_memX" to "acpi_ras_mem_idX"
because memory scrub instances across all NUMA domains would present under
"acpi_ras_mem_id0" when a system uses a single PCC channel for RAS2 scrubbers across
all NUMA domains etc.
2.5. Removed Acked-by: Rafael from patch [2], because of the several above changes from v9.

v8 -> v9:
1. Added following changes for feedback from Yazen.
1.1 In ras2_check_pcc_chan(..) function
- u32 variables moved to the same line.
- Updated error log for readw_relaxed_poll_timeout()
- Added error log for if (status & PCC_STATUS_ERROR), error condition.
- Removed an impossible condition check.
1.2. Added guard for ras2_pc_list_lock in ras2_get_pcc_subspace().

2. Rebased to linux.git v6.16-rc2 [2].

v7 -> v8:
1. Rebased to linux.git v6.16-rc1 [2].

v6 -> v7:
1. Fix for the issue reported by Daniel,
In ras2_check_pcc_chan(), add read, clear and check RAS2 set_cap_status outside
if (status & PCC_STATUS_ERROR) check.
https://lore.kernel.org/all/51bcb52c-4132-4daf-8903-29b121c485a1@os.amperecomputing.com/

v5 -> v6:
1. Fix for the issue reported by Daniel, in start scrubbing with correct addr and size
after firmware return INVALID DATA error for scrub request with invalid addr or size.
https://lore.kernel.org/all/8cdf7885-31b3-4308-8a7c-f4e427486429@os.amperecomputing.com/

v4 -> v5:
1. Fix for the build warnings reported by kernel test robot.
https://patchwork.kernel.org/project/linux-edac/patch/20250423163511.1412-3-shiju.jose@huawei.com/
2. Removed patch "ACPI: ACPI 6.5: RAS2: Rename RAS2 table structure and field names"
from the series as the patch was merged to linux-pm.git : branch linux-next
3. Rebased to ras.git: edac-for-next branch merged with linux-pm.git : linux-next branch.

v3 -> v4:
1. Changes for feedbacks from Yazen on v3.
https://lore.kernel.org/all/20250415210504.GA854098@yaz-khff2.amd.com/

v2 -> v3:
1. Rename RAS2 table structure and field names in
include/acpi/actbl2.h limited to only necessary
for RAS2 scrub feature.
2. Changes for feedbacks from Jonathan on v2.
3. Daniel reported a known behaviour: when readback 'size' attribute after
setting in, returns 0 before starting scrubbing via 'addr' attribute.
Changes added to fix this.
4. Daniel reported that firmware cannot update status of demand scrubbing
via the 'Actual Address Range (OUTPUT)', thus add workaround in the
kernel to update sysfs 'addr' attribute with the status of demand
scrubbing.
5. Optimized logic in ras2_check_pcc_chan() function
(patch - ACPI:RAS2: Add ACPI RAS2 driver).
6. Add PCC channel lock to struct ras2_pcc_subspace and change
lock in ras2_mem_ctx as a pointer to pcc channel lock to make sure
writing to PCC subspace shared memory is protected from race conditions.

v1 -> v2:
1. Changes for feedbacks from Borislav.
- Shorten ACPI RAS2 structures and variables names.
- Shorten some of the other variables in the RAS2 drivers.
- Fixed few CamelCases.

2. Changes for feedbacks from Yazen.
- Added newline after number of '}' and return statements.
- Changed return type for "ras2_add_aux_device() to 'int'.
- Deleted a duplication of acpi_get_table("RAS2",...) in the ras2_acpi_parse_table().
- Add "FW_WARN" to few error logs in the ras2_acpi_parse_table().
- Rename ras2_acpi_init() to acpi_ras2_init() and modified to call acpi_ras2_init()
function from the acpi_init().
- Moved scrub related variables from the struct ras2_mem_ctx from patch
"ACPI:RAS2: Add ACPI RAS2 driver" to "ras: mem: Add memory ACPI RAS2 driver".

Shiju Jose (2):
ACPI:RAS2: Add driver for the ACPI RAS2 feature table
ras: mem: Add ACPI RAS2 memory driver

Documentation/ABI/testing/sysfs-edac-scrub | 13 +-
Documentation/edac/scrub.rst | 58 +++
drivers/acpi/Kconfig | 12 +
drivers/acpi/Makefile | 1 +
drivers/acpi/bus.c | 3 +
drivers/acpi/ras2.c | 398 ++++++++++++++++++++
drivers/edac/scrub.c | 12 +
drivers/ras/Kconfig | 12 +
drivers/ras/Makefile | 1 +
drivers/ras/acpi_ras2.c | 403 +++++++++++++++++++++
include/acpi/ras2.h | 74 ++++
include/linux/edac.h | 4 +
12 files changed, 986 insertions(+), 5 deletions(-)
create mode 100644 drivers/acpi/ras2.c
create mode 100644 drivers/ras/acpi_ras2.c
create mode 100644 include/acpi/ras2.h

--
2.43.0