diff --git a/Cargo.lock b/Cargo.lock
index 8bfc35eb4..a580ead37 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2038,6 +2038,7 @@ dependencies = [
 name = "drv-stm32xx-sys-api"
 version = "0.1.0"
 dependencies = [
+ "build-stm32xx-sys",
  "byteorder",
  "cfg-if",
  "counters",
diff --git a/build/stm32xx-sys/src/lib.rs b/build/stm32xx-sys/src/lib.rs
index b5498a091..0018f734d 100644
--- a/build/stm32xx-sys/src/lib.rs
+++ b/build/stm32xx-sys/src/lib.rs
@@ -2,14 +2,16 @@
 // 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 anyhow::Context;
 use quote::{quote, TokenStreamExt};
 use serde::Deserialize;
-use std::collections::BTreeMap;
+use std::{collections::BTreeMap, io::Write};
 
 #[derive(Deserialize, Default)]
-#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+#[serde(rename_all = "kebab-case")]
 pub struct SysConfig {
     /// EXTI interrupts
+    #[serde(default)]
     gpio_irqs: BTreeMap<String, GpioIrqConfig>,
 }
 
@@ -17,7 +19,7 @@ pub struct SysConfig {
 #[serde(rename_all = "kebab-case", deny_unknown_fields)]
 struct GpioIrqConfig {
     port: Port,
-    pin: u8,
+    pin: usize,
     owner: GpioIrqOwner,
 }
 
@@ -68,6 +70,62 @@ to_tokens_enum! {
     }
 }
 
+pub fn build_gpio_irq_pins() -> anyhow::Result<()> {
+    let out_dir = build_util::out_dir();
+    let dest_path = out_dir.join("gpio_irq_pins.rs");
+    let mut out = std::fs::File::create(&dest_path).with_context(|| {
+        format!("failed to create file '{}'", dest_path.display())
+    })?;
+
+    let Some(sys_config) =
+        build_util::other_task_full_config::<SysConfig>("sys")?.config
+    else {
+        // No GPIO IRQs are configured; nothing left to do here!
+        return Ok(());
+    };
+
+    let task = build_util::task_name();
+    let pins = sys_config
+        .gpio_irqs
+        .iter()
+        .filter_map(|(name, cfg)| {
+            let &GpioIrqConfig {
+                pin,
+                port,
+                ref owner,
+            } = cfg;
+            // Only generate constants for pins owned by the current task.
+            if owner.name != task {
+                return None;
+            }
+
+            let name = match to_const_name(name.clone()) {
+                Ok(name) => name,
+                Err(e) => return Some(Err(e)),
+            };
+
+            Some(Ok(quote! {
+                pub const #name: PinSet = #port.pin(#pin);
+            }))
+        })
+        .collect::<anyhow::Result<Vec<_>>>()?;
+
+    // Don't generate an empty module if there are no pins.
+    if pins.is_empty() {
+        return Ok(());
+    }
+
+    let tokens = quote! {
+        pub mod gpio_irq_pins {
+            use drv_stm32xx_gpio_common::{PinSet, Port};
+            #( #pins )*
+        }
+    };
+    writeln!(out, "{tokens}")?;
+
+    Ok(())
+}
+
 impl SysConfig {
     pub fn load() -> anyhow::Result<Self> {
         Ok(build_util::task_maybe_config::<Self>()?.unwrap_or_default())
@@ -111,7 +169,7 @@ impl SysConfig {
                     let task = syn::parse_str(&owner.name)?;
                     let note = quote::format_ident!(
                         "{}_MASK",
-                        owner.notification.to_uppercase().replace('-', "_")
+                        to_const_name(owner.notification.clone())?
                     );
 
                     let name = quote::format_ident!(
@@ -181,3 +239,10 @@ impl SysConfig {
         })
     }
 }
+
+fn to_const_name(mut s: String) -> anyhow::Result<syn::Ident> {
+    s.make_ascii_uppercase();
+    let s = s.replace("-", "_");
+    syn::parse_str::<syn::Ident>(&s)
+        .with_context(|| format!("`{s}` is not a valid Rust identifier"))
+}
diff --git a/build/util/src/lib.rs b/build/util/src/lib.rs
index c4f062675..5054e4767 100644
--- a/build/util/src/lib.rs
+++ b/build/util/src/lib.rs
@@ -42,6 +42,11 @@ pub fn target_os() -> String {
     std::env::var("CARGO_CFG_TARGET_OS").unwrap()
 }
 
+/// Reads the `HUBRIS_TASK_NAME` env var.
+pub fn task_name() -> String {
+    crate::env_var("HUBRIS_TASK_NAME").expect("missing HUBRIS_TASK_NAME")
+}
+
 /// Checks to see whether the given feature is enabled
 pub fn has_feature(s: &str) -> bool {
     std::env::var(format!(
@@ -104,12 +109,10 @@ pub fn config<T: DeserializeOwned>() -> Result<T> {
 
 /// Pulls the task configuration. See `config` for more details.
 pub fn task_config<T: DeserializeOwned>() -> Result<T> {
-    let task_name =
-        crate::env_var("HUBRIS_TASK_NAME").expect("missing HUBRIS_TASK_NAME");
     task_maybe_config()?.ok_or_else(|| {
         anyhow!(
             "app.toml missing task config section [tasks.{}.config]",
-            task_name
+            task_name()
         )
     })
 }
diff --git a/drv/stm32h7-sprot-server/src/main.rs b/drv/stm32h7-sprot-server/src/main.rs
index efcc639ea..d694e6037 100644
--- a/drv/stm32h7-sprot-server/src/main.rs
+++ b/drv/stm32h7-sprot-server/src/main.rs
@@ -97,7 +97,10 @@ const MAX_UPDATE_ATTEMPTS: u16 = 3;
 // On the flipside, we have learned via unintended experiment that 5ms is too short!
 const DUMP_TIMEOUT: u32 = 1000;
 
-// ROT_IRQ comes from app.toml
+// On Gemini, the STM32H753 is in a LQFP176 package with ROT_IRQ
+// on pin2/PE3
+use drv_stm32xx_sys_api::gpio_irq_pins::ROT_IRQ;
+
 // We use spi3 on gimletlet and spi4 on gemini and gimlet.
 // You should be able to move the RoT board between SPI3, SPI4, and SPI6
 // without much trouble even though SPI3 is the preferred connector and
@@ -117,20 +120,10 @@ cfg_if::cfg_if! {
             target_board = "psc-c",
             target_board = "gemini-bu-1"
             ))] {
-        const ROT_IRQ: sys_api::PinSet = sys_api::PinSet {
-            // On Gemini, the STM32H753 is in a LQFP176 package with ROT_IRQ
-            // on pin2/PE3
-            port: sys_api::Port::E,
-            pin_mask: 1 << 3,
-        };
         const ROT_SPI_DEVICE: u8 = drv_spi_api::devices::ROT;
         fn debug_config(_sys: &sys_api::Sys) { }
         fn debug_set(_sys: &sys_api::Sys, _asserted: bool) { }
     } else if #[cfg(target_board = "gimletlet-2")] {
-        const ROT_IRQ: sys_api::PinSet = sys_api::PinSet {
-            port: sys_api::Port::D,
-            pin_mask: 1 << 0,
-        };
         const DEBUG_PIN: sys_api::PinSet = sys_api::PinSet {
             port: sys_api::Port::E,
             pin_mask: 1 << 6,
@@ -151,7 +144,7 @@ cfg_if::cfg_if! {
         }
         const ROT_SPI_DEVICE: u8 = drv_spi_api::devices::SPI3_HEADER;
     } else {
-        compile_error!("No configuration for ROT_IRQ");
+        compile_error!("No configuration for ROT_SPI_DEVICE");
     }
 }
 
diff --git a/drv/stm32xx-sys-api/Cargo.toml b/drv/stm32xx-sys-api/Cargo.toml
index d46974634..60fc89b84 100644
--- a/drv/stm32xx-sys-api/Cargo.toml
+++ b/drv/stm32xx-sys-api/Cargo.toml
@@ -18,6 +18,7 @@ userlib = { path = "../../sys/userlib" }
 
 [build-dependencies]
 idol.workspace = true
+build-stm32xx-sys = { path = "../../build/stm32xx-sys" }
 
 [features]
 family-stm32h7 = ["drv-stm32xx-gpio-common/family-stm32h7"]
diff --git a/drv/stm32xx-sys-api/build.rs b/drv/stm32xx-sys-api/build.rs
index 41c969ce9..4bd6cdd3f 100644
--- a/drv/stm32xx-sys-api/build.rs
+++ b/drv/stm32xx-sys-api/build.rs
@@ -3,6 +3,7 @@
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
 fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    build_stm32xx_sys::build_gpio_irq_pins()?;
     idol::client::build_client_stub(
         "../../idl/stm32xx-sys.idol",
         "client_stub.rs",
diff --git a/drv/stm32xx-sys-api/src/lib.rs b/drv/stm32xx-sys-api/src/lib.rs
index 5931eb230..f4fd5cc5a 100644
--- a/drv/stm32xx-sys-api/src/lib.rs
+++ b/drv/stm32xx-sys-api/src/lib.rs
@@ -367,3 +367,4 @@ impl From<Option<bool>> for IrqControl {
 }
 
 include!(concat!(env!("OUT_DIR"), "/client_stub.rs"));
+include!(concat!(env!("OUT_DIR"), "/gpio_irq_pins.rs"));
diff --git a/task/nucleo-user-button/src/main.rs b/task/nucleo-user-button/src/main.rs
index ae3acf667..8f85c4c5f 100644
--- a/task/nucleo-user-button/src/main.rs
+++ b/task/nucleo-user-button/src/main.rs
@@ -11,7 +11,7 @@
 #![no_std]
 #![no_main]
 
-use drv_stm32xx_sys_api::{Edge, IrqControl, PinSet, Port, Pull};
+use drv_stm32xx_sys_api::{Edge, IrqControl, Pull};
 use ringbuf::ringbuf_entry;
 use userlib::*;
 
@@ -72,10 +72,7 @@ pub fn main() -> ! {
     });
 
     sys.gpio_configure_input(
-        PinSet {
-            port: Port::C,
-            pin_mask: (1 << 13),
-        },
+        drv_stm32xx_sys_api::gpio_irq_pins::BUTTON,
         Pull::None,
     );