Lib lpc55 rng seed

app/lpc55xpresso/app.toml

@@ -113,11 +113,11 @@ task-slots = ["gpio_driver", "syscon_driver"]
 [tasks.rng_driver]
 name = "drv-lpc55-rng"
 priority = 3
-max-sizes = {flash = 16384, ram = 4096}
 uses = ["rng", "pmc"]
 start = true
-stacksize = 2200
+stacksize = 3504
 task-slots = ["syscon_driver"]
+extern-regions = ["dice_certs", "dice_rng"]
 
 [tasks.pong]
 name = "task-pong"

app/oxide-rot-1/app-dev.toml

@@ -165,6 +165,15 @@ stacksize = 12304
 start = true
 extern-regions = ["dice_alias", "dice_certs"]
 
+[tasks.rng_driver]
+name = "drv-lpc55-rng"
+priority = 6
+uses = ["rng", "pmc"]
+start = true
+stacksize = 4200
+task-slots = ["syscon_driver"]
+extern-regions = ["dice_certs", "dice_rng"]
+
 [signing.certs]
 signing-certs = ["../../support/fake_certs/fake_certificate.der.crt"]
 root-certs = ["../../support/fake_certs/fake_certificate.der.crt"]

app/rot-carrier/app.toml

@@ -99,11 +99,11 @@ pins = [
 [tasks.rng_driver]
 name = "drv-lpc55-rng"
 priority = 5
-max-sizes = {flash = 16384, ram = 4096}
 uses = ["rng", "pmc"]
 start = true
-stacksize = 2200
+stacksize = 4200
 task-slots = ["syscon_driver"]
+extern-regions = ["dice_certs", "dice_rng"]
 
 [tasks.sprot]
 name = "drv-lpc55-sprot-server"

chips/lpc55/memory.toml

@@ -156,3 +156,19 @@ size = 0x800
 read = true
 write = true
 execute = false
+
+[[dice_rng]]
+name = "a"
+address =0x40101a00
+size = 0x100
+read = true
+write = true
+execute = false
+
+[[dice_rng]]
+name = "b"
+address =0x40101a00
+size = 0x100
+read = true
+write = true
+execute = false

drv/lpc55-rng/Cargo.toml

@@ -5,21 +5,37 @@ edition = "2021"
 
 [dependencies]
 cfg-if = { workspace = true }
+hubpack.workspace = true
 idol-runtime = { workspace = true }
-lpc55-pac = { workspace = true }
+lpc55-pac.workspace = true
 num-traits = { workspace = true }
 rand_chacha = { workspace = true }
 rand_core = { workspace = true }
+serde.workspace = true
+sha3.workspace = true
 zerocopy = { workspace = true }
+zeroize.workspace = true
 
 drv-lpc55-syscon-api = { path = "../lpc55-syscon-api" }
 drv-rng-api = { path = "../rng-api" }
+lib-dice.path = "../../lib/dice"
+lib-lpc55-rng.path = "../../lib/lpc55-rng"
+mutable-statics.path = "../../lib/mutable-statics"
+ringbuf.path = "../../lib/ringbuf"
+stage0-handoff = { path = "../../lib/stage0-handoff", optional = true }
 userlib = { path = "../../sys/userlib", features = ["panic-messages"] }
 
 [build-dependencies]
-idol = { workspace = true }
+anyhow.workspace = true
+build-util.path = "../../build/util"
+cfg-if.workspace = true
+idol.workspace = true
+indexmap = { workspace = true, optional = true }
+serde.workspace = true
 
 [features]
+default = ["dice-seed"]
+dice-seed = ["indexmap", "stage0-handoff"]
 no-ipc-counters = ["idol/no-counters"]
 
 # This section is here to discourage RLS/rust-analyzer from doing test builds,

drv/lpc55-rng/build.rs

@@ -2,15 +2,75 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
-fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+use anyhow::{anyhow, Result};
+use idol::{server::ServerStyle, CounterSettings};
+
+cfg_if::cfg_if! {
+    if #[cfg(feature = "dice-seed")] {
+        mod data_region {
+            include!("src/data-region.rs");
+        }
+        use anyhow::Context;
+        use data_region::DataRegion;
+        use indexmap::IndexMap;
+        use std::{fs::File, io::Write};
+
+        const CFG_SRC: &str = "rng-config.rs";
+    }
+}
+
+#[cfg(feature = "dice-seed")]
+fn extern_region_to_cfg<W: Write>(
+    out: &mut W,
+    data_regions: &IndexMap<String, DataRegion>,
+    name: &str,
+) -> Result<()> {
+    let region = data_regions.get(name).ok_or_else(|| {
+        anyhow::anyhow!(format!("external region not found: {}", name))
+    })?;
+
+    Ok(writeln!(
+        out,
+        r##"pub const {}_REGION: DataRegion = DataRegion {{
+    address: {:#x},
+    size: {:#x},
+}};"##,
+        name.to_uppercase(),
+        region.address,
+        region.size
+    )?)
+}
+
+#[cfg(feature = "dice-seed")]
+fn extern_regions_to_cfg(path: &str) -> Result<()> {
+    let out_dir = build_util::out_dir();
+    let dest_path = out_dir.join(path);
+    let mut out =
+        File::create(dest_path).context(format!("creating {}", path))?;
+
+    let data_regions = build_util::task_extern_regions::<DataRegion>()?;
+    if data_regions.is_empty() {
+        return Err(anyhow!("no data regions found"));
+    }
+
+    writeln!(out, "use crate::data_region::DataRegion;\n\n")?;
+
+    extern_region_to_cfg(&mut out, &data_regions, "dice_certs")?;
+    extern_region_to_cfg(&mut out, &data_regions, "dice_rng")
+}
+
+fn main() -> Result<()> {
     idol::Generator::new()
-        .with_counters(
-            idol::CounterSettings::default().with_server_counters(false),
-        )
+        .with_counters(CounterSettings::default().with_server_counters(false))
         .build_server_support(
             "../../idl/rng.idol",
             "server_stub.rs",
-            idol::server::ServerStyle::InOrder,
-        )?;
+            ServerStyle::InOrder,
+        )
+        .map_err(|e| anyhow!(e))?;
+
+    #[cfg(feature = "dice-seed")]
+    extern_regions_to_cfg(CFG_SRC)?;
+
     Ok(())
 }

drv/lpc55-rng/src/config.rs

@@ -0,0 +1,54 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+use crate::data_region::DataRegion;
+use hubpack::SerializedSize;
+use serde::Deserialize;
+use stage0_handoff::{HandoffData, HandoffDataLoadError};
+
+pub enum HandoffDataRegion {
+    DiceCerts,
+    DiceRng,
+}
+
+pub const DICE_CERTS: HandoffDataRegion = HandoffDataRegion::DiceCerts;
+pub const DICE_RNG: HandoffDataRegion = HandoffDataRegion::DiceRng;
+
+// This file is generated by the crate build.rs.
+mod build {
+    include!(concat!(env!("OUT_DIR"), "/rng-config.rs"));
+}
+
+use build::{DICE_CERTS_REGION, DICE_RNG_REGION};
+
+impl HandoffDataRegion {
+    pub fn data_region(&self) -> DataRegion {
+        match self {
+            Self::DiceCerts => DICE_CERTS_REGION,
+            Self::DiceRng => DICE_RNG_REGION,
+        }
+    }
+
+    /// Load a type implementing HandoffData (and others) from a config::DataRegion.
+    /// Errors will be reported in the ringbuf and will return None.
+    #[inline(always)]
+    pub fn load_data<
+        T: for<'a> Deserialize<'a> + HandoffData + SerializedSize,
+    >(
+        &self,
+    ) -> Result<T, HandoffDataLoadError> {
+        use core::slice;
+
+        let region = self.data_region();
+        // Safety: This memory is setup by code executed before hubris and
+        // exposed using the kernel `extern-regions` mechanism. The safety of
+        // this code is an extension of our trust in the hubris pre-main, kernel,
+        // and build process.
+        let data = unsafe {
+            slice::from_raw_parts(region.address as *mut u8, region.size)
+        };
+
+        T::load_from_addr(data)
+    }
+}

drv/lpc55-rng/src/data-region.rs

@@ -0,0 +1,10 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#[derive(serde::Deserialize, Default, Debug)]
+#[serde(rename_all = "kebab-case")]
+pub struct DataRegion {
+    pub address: usize,
+    pub size: usize,
+}