[PATCH v7] x86/mce: retrieve poison range from hardware

Jane Chu
2022-08-02T19:51:39Z

With Commit 7917f9cdb503 ("acpi/nfit: rely on mce->misc to determine
poison granularity") that changed nfit_handle_mce() callback to report
badrange according to 1ULL << MCI_MISC_ADDR_LSB(mce->misc), it's been
discovered that the mce->misc LSB field is 0x1000 bytes, hence injecting
2 back-to-back poisons and the driver ends up logging 8 badblocks,
because 0x1000 bytes is 8 512-byte.

Dan Williams noticed that apei_mce_report_mem_error() hardcode
the LSB field to PAGE_SHIFT instead of consulting the input
struct cper_sec_mem_err record. So change to rely on hardware whenever
support is available.

Link: https://lore.kernel.org/r/7ed50fd8-521e-cade-77b1-738b8bfb8502@oracle.com

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jane Chu <jane.chu@oracle.com>
---
arch/x86/kernel/cpu/mce/apei.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
index 717192915f28..8ed341714686 100644
--- a/arch/x86/kernel/cpu/mce/apei.c
+++ b/arch/x86/kernel/cpu/mce/apei.c
@@ -29,15 +29,26 @@
void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
{
struct mce m;
+ int lsb;

if (!(mem_err->validation_bits & CPER_MEM_VALID_PA))
return;

+ /*
+ * Even if the ->validation_bits are set for address mask,
+ * to be extra safe, check and reject an error radius '0',
+ * and fall back to the default page size.
+ */
+ if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK)
+ lsb = find_first_bit((void *)&mem_err->physical_addr_mask, PAGE_SHIFT);
+ else
+ lsb = PAGE_SHIFT;
+
mce_setup(&m);
m.bank = -1;
/* Fake a memory read error with unknown channel */
m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | MCI_STATUS_MISCV | 0x9f;
- m.misc = (MCI_MISC_ADDR_PHYS << 6) | PAGE_SHIFT;
+ m.misc = (MCI_MISC_ADDR_PHYS << 6) | lsb;

if (severity >= GHES_SEV_RECOVERABLE)
m.status |= MCI_STATUS_UC;
--
2.18.4