diff --git a/.gitignore b/.gitignore
index ed1117f..ea8c4bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1 @@
 /target
-.vscode/settings.json
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..83a9058
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,9 @@
+{
+    "git.alwaysSignOff": true,
+    "rust-analyzer.check.overrideCommand": [
+        "cargo",
+        "xtask",
+        "check",
+        "--json"
+    ]
+}
\ No newline at end of file
diff --git a/README.md b/README.md
index c78a8a0..a59eb49 100644
--- a/README.md
+++ b/README.md
@@ -24,8 +24,12 @@ Right now, r9 is not self-hosting.
 
 `cargo xtask dist`, which `cargo xtask qemu` and 
 `cargo xtask qemukvm` depend on, requires `llvm-objcopy`. 
-This is expected to live in the rust toolchain path. If 
-you get `No such file or directory (os error 2)` messages, 
+This is expected to live in the rust toolchain path.  You can install by running:
+```
+rustup component add llvm-tools
+```
+
+If you get `No such file or directory (os error 2)` messages, 
 then install `llvm` separate from the rust toolchain and set:
 ```
 OBJCOPY=$(which llvm-objcopy) cargo xtask qemukvm
diff --git a/aarch64/Cargo.toml b/aarch64/Cargo.toml
index 340fcda..ee51820 100644
--- a/aarch64/Cargo.toml
+++ b/aarch64/Cargo.toml
@@ -4,7 +4,7 @@ cargo-features = ["per-package-target"]
 name = "aarch64"
 version = "0.1.0"
 edition = "2021"
-default-target = "aarch64-unknown-none-softfloat"
+default-target = "aarch64-unknown-none"
 
 [dependencies]
 bitstruct = "0.1"
diff --git a/aarch64/src/runtime.rs b/aarch64/src/runtime.rs
index 331570e..f24a4a0 100644
--- a/aarch64/src/runtime.rs
+++ b/aarch64/src/runtime.rs
@@ -15,7 +15,7 @@ use port::mem::VirtRange;
 //  - Use Console via println!() macro once available
 //  - Add support for raspi4
 #[panic_handler]
-pub extern "C" fn panic(info: &PanicInfo) -> ! {
+pub fn panic(info: &PanicInfo) -> ! {
     let mmio = rpi_mmio().expect("mmio base detect failed").to_virt();
 
     let gpio_range = VirtRange::with_len(mmio + 0x200000, 0xb4);
diff --git a/aarch64/src/trap.S b/aarch64/src/trap.S
index 6dbdea9..0dee4c5 100644
--- a/aarch64/src/trap.S
+++ b/aarch64/src/trap.S
@@ -99,6 +99,7 @@
 /// Each entry is 16 instructions/128 bytes.
 /// Ventry handles alignment of individual entries.
 .balign	2048
+.globl exception_vectors
 exception_vectors:
 	// Current EL with SP0
 	ventry	sync_invalid_el1t			// Synchronous EL1t
diff --git a/riscv64/src/sbi.rs b/riscv64/src/sbi.rs
index 395ce76..db35524 100644
--- a/riscv64/src/sbi.rs
+++ b/riscv64/src/sbi.rs
@@ -2,7 +2,7 @@
 //!
 //! Chapter 5: Legacy Extensions
 
-#![cfg_attr(not(target_arch = "riscv64"), allow(dead_code))]
+#![allow(dead_code)]
 
 const SBI_SET_TIMER: usize = 0;
 const SBI_CONSOLE_PUTCHAR: usize = 1;
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 5c471d8..6e48daf 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -2,7 +2,7 @@
 channel = "nightly-2023-06-05"
 components = [ "rustfmt", "rust-src", "clippy", "llvm-tools" ]
 targets = [
-  "aarch64-unknown-none-softfloat",
+  "aarch64-unknown-none",
   "riscv64imac-unknown-none-elf",
   "x86_64-unknown-none"
 ]
diff --git a/x86_64/src/runtime.rs b/x86_64/src/runtime.rs
index 592aba1..6535d47 100644
--- a/x86_64/src/runtime.rs
+++ b/x86_64/src/runtime.rs
@@ -6,7 +6,7 @@ use alloc::alloc::{GlobalAlloc, Layout};
 use core::panic::PanicInfo;
 
 #[panic_handler]
-pub extern "C" fn panic(_info: &PanicInfo) -> ! {
+pub fn panic(_info: &PanicInfo) -> ! {
     #[allow(clippy::empty_loop)]
     loop {}
 }
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 0097244..b7a6f2c 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -35,6 +35,7 @@ impl fmt::Display for Arch {
     }
 }
 
+// TODO This is becoming a bag of random fields - maybe turn into an enum
 struct BuildParams {
     arch: Arch,
     profile: Profile,
@@ -42,11 +43,16 @@ struct BuildParams {
     wait_for_gdb: bool,
     config: Configuration,
     dump_dtb: String,
+    json_output: bool,
 }
 
 impl BuildParams {
     fn new(matches: &clap::ArgMatches) -> Self {
-        let profile = if matches.get_flag("release") { Profile::Release } else { Profile::Debug };
+        let profile = if matches.try_contains_id("release").unwrap_or(false) {
+            Profile::Release
+        } else {
+            Profile::Debug
+        };
         let verbose = matches.get_flag("verbose");
         let arch = matches.try_get_one("arch").ok().flatten().unwrap_or(&Arch::X86_64);
         let wait_for_gdb =
@@ -67,7 +73,9 @@ impl BuildParams {
             config_file
         ));
 
-        Self { arch: *arch, profile, verbose, wait_for_gdb, dump_dtb, config }
+        let json_output = matches.try_contains_id("json").unwrap_or(false);
+
+        Self { arch: *arch, profile, verbose, wait_for_gdb, dump_dtb, config, json_output }
     }
 
     fn dir(&self) -> &'static str {
@@ -164,6 +172,12 @@ fn main() {
                 clap::arg!(--verbose "Print commands"),
             ]),
         )
+        .subcommand(
+            clap::Command::new("check")
+                .about("Runs check")
+                .args(&[clap::arg!(--json "Output messages as json")])
+                .args(&[clap::arg!(--verbose "Print commands")]),
+        )
         .subcommand(
             clap::Command::new("qemu").about("Run r9 under QEMU").args(&[
                 clap::arg!(--release "Build a release version").conflicts_with("debug"),
@@ -201,6 +215,7 @@ fn main() {
         Some(("dist", m)) => dist(&BuildParams::new(m)),
         Some(("test", m)) => test(&BuildParams::new(m)),
         Some(("clippy", m)) => clippy(&BuildParams::new(m)),
+        Some(("check", m)) => check(&BuildParams::new(m)),
         Some(("qemu", m)) => run(&BuildParams::new(m)),
         Some(("qemukvm", m)) => accelrun(&BuildParams::new(m)),
         Some(("clean", _)) => clean(),
@@ -426,7 +441,88 @@ fn clippy(build_params: &BuildParams) -> Result<()> {
     }
     let status = annotated_status(&mut cmd)?;
     if !status.success() {
-        return Err("build kernel failed".into());
+        return Err("clippy failed".into());
+    }
+    Ok(())
+}
+
+fn check(build_params: &BuildParams) -> Result<()> {
+    let all_check_args = vec![
+        vec!["check", "--package", "aarch64", "--bins"],
+        vec!["check", "--package", "x86_64", "--bins"],
+        vec!["check", "--package", "riscv64", "--bins"],
+        vec!["check", "--package", "port", "--lib"],
+        vec![
+            "check",
+            "--package",
+            "aarch64",
+            "--tests",
+            "--benches",
+            "--target",
+            "aarch64-unknown-linux-gnu",
+        ],
+        vec![
+            "check",
+            "--package",
+            "x86_64",
+            "--tests",
+            "--benches",
+            "--target",
+            "x86_64-unknown-linux-gnu",
+        ],
+        vec![
+            "check",
+            "--package",
+            "riscv64",
+            "--tests",
+            "--benches",
+            "--target",
+            "riscv64gc-unknown-linux-gnu",
+        ],
+        vec![
+            "check",
+            "--package",
+            "port",
+            "--tests",
+            "--benches",
+            "--target",
+            "aarch64-unknown-linux-gnu",
+        ],
+        vec![
+            "check",
+            "--package",
+            "port",
+            "--tests",
+            "--benches",
+            "--target",
+            "x86_64-unknown-linux-gnu",
+        ],
+        vec![
+            "check",
+            "--package",
+            "port",
+            "--tests",
+            "--benches",
+            "--target",
+            "riscv64gc-unknown-linux-gnu",
+        ],
+    ];
+
+    for check_args in all_check_args {
+        let mut cmd = Command::new(cargo());
+        cmd.args(check_args);
+        if build_params.json_output {
+            cmd.arg("--message-format=json").arg("--quiet");
+        }
+        cmd.current_dir(workspace());
+
+        if build_params.verbose {
+            println!("Executing {cmd:?}");
+        }
+        let status = annotated_status(&mut cmd)?;
+        if !status.success() {
+            return Err("check failed".into());
+        }
     }
     Ok(())
 }