From: Sai Praneeth <sai.praneeth.prakhya@xxxxxxxxx> UEFI specification v2.6 recommends not to use "EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA" attribute of EFI_PROPERTIES_TABLE. Presently, this is the *only* bit defined in EFI_PROPERTIES_TABLE. This bit implies that EFI Runtime code and data regions of an executable image are separate and are aligned as specified in spec. Please refer to "EFI_PROPERTIES_TABLE" in section 4.6 of UEFI specification v2.6 for more information on this table. UEFI v2.6 introduces EFI_MEMORY_ATTRIBUTES_TABLE and is intended to replace EFI_PROPERTIES_TABLE. If EFI_MEMORY_ATTRIBUTES_TABLE is found we skip updating of efi runtime region mappings based on EFI_PROPERTIES_TABLE, so let's also skip parsing of EFI_PROPERTIES_TABLE if we find EFI_MEMORY_ATTRIBUTES_TABLE because we are not using this table anyways. The only caveat here is, if further versions of UEFI spec adds some more bits (hence some more attributes) to EFI_PROPERTIES_TABLE then we might need to parse it again, otherwise there is no good in doing that. We can also expect that the same attributes might be reflected in EFI_MEMORY_ATTRIBUTES_TABLE and hence saving us from parsing EFI_PROPERTIES_TABLE again. Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx> Cc: Lee, Chun-Yi <jlee@xxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> --- drivers/firmware/efi/efi.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index e7d404059b73..e6c6feaa4d78 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -531,6 +531,17 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, efi_memattr_init(); + /* + * Since EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace + * EFI_PROPERTIES_TABLE, let's skip parsing of EFI_PROPERTIES_TABLE + * if we find EFI_MEMORY_ATTRIBUTES_TABLE. + * Note: We might need to *re-enable* parsing of EFI_PROPERTIES_TABLE + * if it defines some bits that are not defined in + * EFI_MEMORY_ATTRIBUTES_TABLE. + */ + if (efi_enabled(EFI_MEM_ATTR)) + return 0; + /* Parse the EFI Properties table if it exists */ if (efi.properties_table != EFI_INVALID_TABLE_ADDR) { efi_properties_table_t *tbl; -- 2.1.4 -- 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