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/[email protected]
Reviewed-by: Dan Williams <[email protected]>
Signed-off-by: Jane Chu <[email protected]>
---
arch/x86/kernel/cpu/mce/apei.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
index 717192915f28..26d63818b2de 100644
--- a/arch/x86/kernel/cpu/mce/apei.c
+++ b/arch/x86/kernel/cpu/mce/apei.c
@@ -29,15 +29,27 @@
void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
{
struct mce m;
+ int grain = PAGE_SHIFT;
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 fallback to the default page size.
+ */
+ if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK) {
+ grain = ~mem_err->physical_addr_mask + 1;
+ if (grain == 1)
+ grain = 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) | grain;
if (severity >= GHES_SEV_RECOVERABLE)
m.status |= MCI_STATUS_UC;
--
2.18.4
Jane Chu wrote:
> 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/[email protected]
>
> Reviewed-by: Dan Williams <[email protected]>
> Signed-off-by: Jane Chu <[email protected]>
> ---
> arch/x86/kernel/cpu/mce/apei.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
> index 717192915f28..26d63818b2de 100644
> --- a/arch/x86/kernel/cpu/mce/apei.c
> +++ b/arch/x86/kernel/cpu/mce/apei.c
> @@ -29,15 +29,27 @@
> void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
> {
> struct mce m;
> + int grain = PAGE_SHIFT;
>
> 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 fallback to the default page size.
> + */
> + if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK) {
> + grain = ~mem_err->physical_addr_mask + 1;
> + if (grain == 1)
> + grain = PAGE_SHIFT;
Wait, if @grain is the number of bits to mask off the address, shouldn't
this be something like:
grain = min_not_zero(PAGE_SHIFT, hweight64(~mem_err->physical_addr_mask));
...?