Catch target-host version mismatch

Attach the version information in a symbol that's generated by the host.
Then, expect the same symbol exists in the embedded target. If the
linker can't resolve this, then the host and target should be
incompatible. I'm overloading the __imxrt_family symbol for this.

2 files changed, 2 insertions, 2 deletions

diff --git a/src/host.rs b/src/host.rs
index 2598d50..902208a 100644
--- a/src/host.rs
+++ b/src/host.rs
@@ -624,7 +624,7 @@ impl RuntimeBuilder {
         )?;
         // The target runtime looks at this value to predicate some pre-init instructions.
         // Could be helpful for binary identification, but it's an undocumented feature.
-        writeln!(writer, "__imxrt_family = {};", self.family.id(),)?;
+        writeln!(writer, "__imxrt_rt_v0.2 = {};", self.family.id(),)?;
 
         let link_x = include_bytes!("host/imxrt-link.x");
         writer.write_all(link_x)?;
diff --git a/src/target.rs b/src/target.rs
index d0e2223..697e591 100644
--- a/src/target.rs
+++ b/src/target.rs
@@ -40,7 +40,7 @@ global_asm! {r#"
 .cfi_startproc
 
 __pre_init:
-    ldr r0, =__imxrt_family         @ Need to know which chip family we're initializing.
+    ldr r0, =__imxrt_rt_v0.2        @ Need to know which chip family we're initializing.
     ldr r1, =1180
     cmp r0, r1                      @ Is this an 1180?
     beq flexram_1180