rt: add FMC compatiblity checks

Add compatiblity check funcion to test FMC compatiblity in runtime.

Signed-off-by: leongross <leon.gross@9elements.com>

error/src/lib.rs

@@ -464,6 +464,8 @@ impl CaliptraError {
     pub const RUNTIME_GET_FMC_CSR_UNSUPPORTED_FMC: CaliptraError =
         CaliptraError::new_const(0x000E0055);
 
+    pub const RUNTIME_FMC_NOT_COMPATIBLE: CaliptraError = CaliptraError::new_const(0x000E0058);
+
     /// FMC Errors
     pub const FMC_GLOBAL_NMI: CaliptraError = CaliptraError::new_const(0x000F0001);
     pub const FMC_GLOBAL_EXCEPTION: CaliptraError = CaliptraError::new_const(0x000F0002);

runtime/src/compatibility.rs

@@ -0,0 +1,39 @@
+/*++
+
+Licensed under the Apache-2.0 license.
+
+File Name:
+
+    compatibility.rs
+
+Abstract:
+
+    File contains compatibility functions to to check if the runtime is
+    compatible with FMC.
+
+--*/
+
+use caliptra_builder::version::RUNTIME_VERSION_MAJOR;
+use caliptra_common::FirmwareHandoffTable;
+
+pub fn is_fmc_compatible(fht: &FirmwareHandoffTable) -> bool {
+    fht.fht_major_ver == RUNTIME_VERSION_MAJOR
+}
+
+#[test]
+fn test_is_fmc_compatible() {
+    let mut fht = FirmwareHandoffTable::default();
+    fht.fht_major_ver = 1;
+    fht.fht_minor_ver = 0;
+    assert_eq!(is_fmc_compatible(&fht), true);
+
+    // change minor version should not affect compatibility
+    fht.fht_minor_ver = 1;
+    assert_eq!(is_fmc_compatible(&fht), true);
+
+    fht.fht_minor_ver = 0xff;
+    assert_eq!(is_fmc_compatible(&fht), true);
+
+    fht.fht_major_ver = 2;
+    assert_eq!(is_fmc_compatible(&fht), false);
+}

runtime/src/lib.rs

@@ -16,6 +16,7 @@ Abstract:
 mod authorize_and_stash;
 mod capabilities;
 mod certify_key_extended;
+pub mod compatibility;
 pub mod dice;
 mod disable;
 mod dpe_crypto;

runtime/src/main.rs

@@ -22,7 +22,7 @@ use caliptra_common::{cprintln, handle_fatal_error};
 use caliptra_cpu::{log_trap_record, TrapRecord};
 use caliptra_error::CaliptraError;
 use caliptra_registers::soc_ifc::SocIfcReg;
-use caliptra_runtime::Drivers;
+use caliptra_runtime::{compatibility, Drivers};
 use core::hint::black_box;
 
 #[cfg(feature = "std")]
@@ -83,10 +83,18 @@ pub extern "C" fn entry_point() -> ! {
         handle_fatal_error(e.into());
     });
 
-    if !drivers.persistent_data.get().fht.is_valid() {
+    let fht = &drivers.persistent_data.get().fht;
+    if !fht.is_valid() {
         cprintln!("[rt] Runtime can't load FHT");
         handle_fatal_error(caliptra_drivers::CaliptraError::RUNTIME_HANDOFF_FHT_NOT_LOADED.into());
     }
+
+    // Test if RT version is compatible with the FMC version
+    if !compatibility::is_fmc_compatible(&fht) {
+        cprintln!("[rt] Runtime is not compatible with FMC");
+        handle_fatal_error(caliptra_drivers::CaliptraError::RUNTIME_FMC_NOT_COMPATIBLE.into());
+    }
+
     cprintln!("[rt] Runtime listening for mailbox commands...");
     if let Err(e) = caliptra_runtime::handle_mailbox_commands(&mut drivers) {
         handle_fatal_error(e.into());