Detect current EL for setting exception vector too.

Author: qwandor

CHANGELOG.md

@@ -4,9 +4,10 @@
 
 ### Improvements
 
-- If the `initial-pagetable` feature is specified without any of the `elX` features, then the
-  exception level will be checked at runtime and the appropriate registers for the current EL will
-  be used.
+- If the `initial-pagetable` or `exceptions` features are specified without any of the `elX`
+  features, then the exception level will be checked at runtime and the appropriate registers for
+  the current EL will be used. The `el1` feature is no longer enabled by default, as this runtime
+  detection should work instead.
 
 ### Bugfixes
 

Cargo.toml

@@ -19,7 +19,7 @@ arm-pl011-uart = "0.4.0"
 smccc = "0.2.2"
 
 [features]
-default = ["el1", "exceptions", "initial-pagetable", "psci"]
+default = ["exceptions", "initial-pagetable", "psci"]
 el1 = []
 el2 = []
 el3 = []

README.md

@@ -46,7 +46,7 @@ fn main() {
 
 ## Features
 
-`el1`, `exceptions`, `initial-pagetable` and `psci` are enabled by default.
+`exceptions`, `initial-pagetable` and `psci` are enabled by default.
 
 ### `el1`
 

src/lib.rs

@@ -76,6 +76,35 @@ extern "C" fn set_exception_vector() {
             out("x9") _,
         );
     }
+    #[cfg(all(
+        feature = "exceptions",
+        not(any(feature = "el1", feature = "el2", feature = "el3"))
+    ))]
+    unsafe {
+        asm!(
+            "mrs x9, CurrentEL",
+            "cmp x9, #3",
+            "b.ne 1f",
+            "adr x9, vector_table_el3",
+            "msr vbar_el3, x9",
+            "b 3f",
+
+        "1:",
+            "cmp x9, #2",
+            "b.ne 2f",
+            "adr x9, vector_table_el2",
+            "msr vbar_el2, x9",
+            "b 3f",
+
+        "2:",
+            "adr x9, vector_table_el1",
+            "msr vbar_el1, x9",
+
+        "3:",
+            options(nomem, nostack),
+            out("x9") _,
+        );
+    }
 }
 
 extern "C" fn rust_entry(arg0: u64, arg1: u64, arg2: u64, arg3: u64) -> ! {