The kernel already tracks recoverable hardware errors (CPU, memory, PCI,
CXL, etc.) in the hwerr_data array for vmcoreinfo crash dump analysis.
However, this data is only accessible after a crash.

This series adds a sysfs directory at /sys/kernel/hwerr_recovery_stats/ to
expose these statistics at runtime, allowing monitoring tools to track
hardware health without requiring a kernel crash.

The directory contains one file per error subsystem:
  /sys/kernel/hwerr_recovery_stats/{cpu, memory, pci, cxl, others}

Each file contains a single integer representing the error count.

This is useful for:
- Proactive detection of failing hardware components
- Time-series tracking of recoverable errors
- System health monitoring in cloud environments

To: akpm@linux-foundation.org
Cc: kexec@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-acpi@vger.kernel.org
To: bhe@redhat.com
Cc: linux-kernel@vger.kernel.org
Cc: dyoung@redhat.com
Cc: tony.luck@intel.com
Cc: xueshuai@linux.alibaba.com
Cc: vgoyal@redhat.com
Cc: zhiquan1.li@intel.com
Cc: olja@meta.com

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changes in v2:
- Renamed vmcore_stats to hwerr_stats
- Separate each subsystem in multiple sysfs entries, one per file
- Link to v1: https://patch.msgid.link/20260129-vmcoreinfo_sysfs-v1-1-164c1fe1fe07@debian.org

---
Breno Leitao (2):
      vmcoreinfo: expose hardware error recovery statistics via sysfs
      docs: add ABI documentation for /sys/kernel/hwerr_recovery_stats/

 .../ABI/testing/sysfs-kernel-hwerr_recovery_stats  | 47 ++++++++++++++++++
 Documentation/driver-api/hw-recoverable-errors.rst |  3 +-
 kernel/vmcore_info.c                               | 55 ++++++++++++++++++++++
 3 files changed, 104 insertions(+), 1 deletion(-)
---
base-commit: 4d310797262f0ddf129e76c2aad2b950adaf1fda
change-id: 20260129-vmcoreinfo_sysfs-ff4687979cd5

Best regards,
--  
Breno Leitao <leitao@debian.org>