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@xxxxxxxxxx>
---
@Matt:
here's v2 of 2/2 only, with your comments addressed.
Thanks,
Ard.
drivers/firmware/efi/efi.c | 18 ++++++++++++++++++
include/linux/efi.h | 1 +
2 files changed, 19 insertions(+)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 5cbb8d31da33..8c81cd58f95f 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -425,6 +425,24 @@ 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;
}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 5b4f3ac08053..61b5a5e1e9be 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -972,6 +972,7 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_PARAVIRT 6 /* Access is via a paravirt interface */
#define EFI_ARCH_1 7 /* First arch-specific bit */
#define EFI_DBG 8 /* Print additional debug info at runtime */
+#define EFI_NX_PE_DATA 9 /* Can runtime data regions be mapped non-executable? */
#ifdef CONFIG_EFI
/*
--
1.9.1
--
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