efi: Introduce EFI_NX_PE_DATA bit and set it from properties table

UEFI v2.5 introduces a runtime memory protection feature that splits
PE/COFF runtime images into separate code and data regions. Since this
may require special handling by the OS, allocate a EFI_xxx bit to
keep track of whether this feature is currently active or not.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index c297d78f50fd..31fc864eb037 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -426,6 +426,24 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
         }
         pr_cont("\n");
         set_bit(EFI_CONFIG_TABLES, &efi.flags);
+
+        /* Parse the EFI Properties table if it exists */
+        if (efi.properties_table != EFI_INVALID_TABLE_ADDR) {
+                efi_properties_table_t *tbl;
+
+                tbl = early_memremap(efi.properties_table, sizeof(*tbl));
+                if (tbl == NULL) {
+                        pr_err("Could not map Properties table!\n");
+                        return -ENOMEM;
+                }
+
+                if (tbl->memory_protection_attribute &
+                    EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA)
+                        set_bit(EFI_NX_PE_DATA, &efi.flags);
+
+                early_memunmap(tbl, sizeof(*tbl));
+        }
+
         return 0;
 }