ACPI 6.0 defines NFIT table and new persistent memory types for EFI memory table (EFI_PERSISTENT_MEMORY) and e820 table (E820_PMEM).
setup_e820() enabled by EFI_STUB converts EFI_PERSISTENT_MEMORY to E820_PMEM for the e820_map table on x86 EFI platforms. When EFI_STUB is disabled, x86 kernels rely on the bootloader to perform this conversion. It was found that the upstream grub bootloader since 2012 has a bug that converts EFI_PERSISTENT_MEMORY (or any new type) to E820_RAM, which causes the kernel to use persistent memory ranges as regular memory and corrupts the data in NVDIMM. Therefore, this patch sets ACPI_NFIT to depend on EFI_STUB on x86. This assures that ACPI_NFIT kernels are self-contained and are protected from the upstream grub bug on x86. Note, X86_PMEM_LEGACY allows the kernel to use the pmem driver on pre-ACPI 6.0 platforms, and does not require ACPI_NFIT enabled. References: http://www.mail-archive.com/grub-devel@gnu.org/msg23961.html Reported-by: Robert Elliott <elli...@hpe.com> Signed-off-by: Toshi Kani <toshi.k...@hpe.com> Cc: Rafael J. Wysocki <r...@rjwysocki.net> Cc: Dan Williams <dan.j.willi...@intel.com> --- drivers/acpi/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 5eef4cb..5368baa 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -441,6 +441,7 @@ config ACPI_NFIT depends on PHYS_ADDR_T_64BIT depends on BLK_DEV depends on ARCH_HAS_MMIO_FLUSH + depends on !X86 || (X86 && EFI_STUB) select LIBNVDIMM help Infrastructure to probe ACPI 6 compliant platforms for -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
