On Tue, 25 Aug, at 10:27:22AM, Jonathan (Zhixiong) Zhang wrote: > From: "Jonathan (Zhixiong) Zhang" <zjzhang@xxxxxxxxxxxxxx> > > If the ACPI APEI firmware handles hardware error first (called "firmware > first handling"), the firmware updates the GHES memory region with hardware > error record (called "generic hardware error record"). Essentially the > firmware writes hardware error records in the GHES memory region, triggers > an NMI/interrupt, then the GHES driver goes off and grabs the error record > from the GHES region. > > The kernel currently maps the GHES memory region as cacheable > (PAGE_KERNEL) for all architectures. However, on some arm64 platforms, > there is a mismatch between how the kernel maps the GHES region > (PAGE_KERNEL) and how the firmware maps it (EFI_MEMORY_UC, ie. > uncacheable), leading to the possibility of the kernel GHES driver > reading stale data from the cache when it receives the interrupt. > > With stale data being read, the kernel is unaware there is new hardware > error to be handled when there actually is; this may lead to further damage > in various scenarios, such as error propagation caused data corruption. > If uncorrected error (such as double bit ECC error) happened in memory > operation and if the kernel is unaware of such event happening, errorneous > data may be propagated to the disk. > > Instead GHES memory region should be mapped with page protection type > according to what is returned from arch_apei_get_mem_attribute(). > > Reviewed-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> > Acked-by: Borislav Petkov <bp@xxxxxxx> > Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx> > --- > drivers/acpi/apei/ghes.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) This patch message looks fine to me. Ingo? -- Matt Fleming, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
