From 63036a9dc50e17a82ea140c8c5946f3ecdbf7b8f Mon Sep 17 00:00:00 2001
From: Anthony Rocha <anthony.rocha@amd.com>
Date: Tue, 27 Oct 2026 11:49:57 -0700
Subject: [PATCH 1/3] targets: sleep in the bootstrap thread instead of
 spinning

Target::main() ends in loop {} after codegen::start(). The kernel runs
target::main() on its bootstrap thread, which has DEFAULT_PRIORITY, and app
threads get DEFAULT_PRIORITY too unless the system config says otherwise. The
scheduler round-robins threads of equal priority at every tick, so a spinning
bootstrap thread takes a full time slice at each tick whenever an app thread is
runnable, and a woken thread can wait behind it. Pigweed's own reference targets
(pw_rp2350 ipc/user, clock/user) end main with
loop { kernel::sleep_until(Arch, Instant::MAX) } instead.

Apply the same to every target whose main() is just codegen::start(); loop {}:
ast10x0 (10 targets), earlgrey (4) and veer (2). Targets whose main() does other
work before looping (peripheral and kernel tests) are unchanged.

Evidence: measured on the Caliptra VeeR FPGA (a downstream fork with more veer
test targets): the 64 KiB PLDM firmware update went from 65.0 s to 49.0 s with
the FD in its own process, and from 52.2 s to 37.3 s with the FD co-located,
about 45 to 48 ms per chunk, and the scheduler tick was measured at 11.29 ms.

NOT yet built or run for this branch; CI should decide. Known risk: in the
downstream fork, with a sleeping bootstrap thread the veer
ipc_runner_emulator_test hangs at "Testing object_set_peer_user_signal"
(passes with the spinner), which looks like a latent wake-up problem the spinner
masks. Expect target/veer/ipc/user to fail until that is understood; the ARM and
earlgrey targets have not been tried.
---
 target/ast10x0/tests/interrupts/user/target.rs           | 9 +++++++--
 target/ast10x0/tests/ipc/user/target.rs                  | 9 +++++++--
 target/ast10x0/tests/mctp/ipc_client/target.rs           | 9 +++++++--
 target/ast10x0/tests/orchestrator/runtime/target.rs      | 9 +++++++--
 target/ast10x0/tests/orchestrator/timer/target.rs        | 9 +++++++--
 target/ast10x0/tests/spdm/responder/target.rs            | 9 +++++++--
 target/ast10x0/tests/stress/ipc/user/target.rs           | 9 +++++++--
 .../tests/stress/process_termination/user/target.rs      | 9 +++++++--
 target/ast10x0/tests/usart/target.rs                     | 9 +++++++--
 .../ast10x0/tests/util_ipc/async_transaction/target.rs   | 9 +++++++--
 target/earlgrey/syscall_latency/target.rs                | 8 +++++++-
 target/earlgrey/tests/drivers/gpio/target.rs             | 8 +++++++-
 target/earlgrey/tests/ipc/user/target.rs                 | 8 +++++++-
 target/earlgrey/tests/uart/target.rs                     | 8 +++++++-
 target/veer/ipc/user/target.rs                           | 8 +++++++-
 target/veer/syscall_latency/target.rs                    | 8 +++++++-
 16 files changed, 112 insertions(+), 26 deletions(-)

diff --git a/target/ast10x0/tests/interrupts/user/target.rs b/target/ast10x0/tests/interrupts/user/target.rs
index ebf027e18..83f54fb7a 100644
--- a/target/ast10x0/tests/interrupts/user/target.rs
+++ b/target/ast10x0/tests/interrupts/user/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/ipc/user/target.rs b/target/ast10x0/tests/ipc/user/target.rs
index 68b95716a..c1ba69aee 100644
--- a/target/ast10x0/tests/ipc/user/target.rs
+++ b/target/ast10x0/tests/ipc/user/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/mctp/ipc_client/target.rs b/target/ast10x0/tests/mctp/ipc_client/target.rs
index 850303c4a..66ecd02f6 100644
--- a/target/ast10x0/tests/mctp/ipc_client/target.rs
+++ b/target/ast10x0/tests/mctp/ipc_client/target.rs
@@ -10,6 +10,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -21,8 +22,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/orchestrator/runtime/target.rs b/target/ast10x0/tests/orchestrator/runtime/target.rs
index 961db53ed..c96088b5e 100644
--- a/target/ast10x0/tests/orchestrator/runtime/target.rs
+++ b/target/ast10x0/tests/orchestrator/runtime/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/orchestrator/timer/target.rs b/target/ast10x0/tests/orchestrator/timer/target.rs
index 12fd4720b..411bdb1a0 100644
--- a/target/ast10x0/tests/orchestrator/timer/target.rs
+++ b/target/ast10x0/tests/orchestrator/timer/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/spdm/responder/target.rs b/target/ast10x0/tests/spdm/responder/target.rs
index b7b25c9e1..0d5b8c3a2 100644
--- a/target/ast10x0/tests/spdm/responder/target.rs
+++ b/target/ast10x0/tests/spdm/responder/target.rs
@@ -6,6 +6,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -17,8 +18,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/stress/ipc/user/target.rs b/target/ast10x0/tests/stress/ipc/user/target.rs
index fd56688f5..f67e46e3e 100644
--- a/target/ast10x0/tests/stress/ipc/user/target.rs
+++ b/target/ast10x0/tests/stress/ipc/user/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/stress/process_termination/user/target.rs b/target/ast10x0/tests/stress/process_termination/user/target.rs
index 66657f16b..a733ff061 100644
--- a/target/ast10x0/tests/stress/process_termination/user/target.rs
+++ b/target/ast10x0/tests/stress/process_termination/user/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -15,8 +16,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/usart/target.rs b/target/ast10x0/tests/usart/target.rs
index 2ab9dc6be..14b9bda3d 100644
--- a/target/ast10x0/tests/usart/target.rs
+++ b/target/ast10x0/tests/usart/target.rs
@@ -9,6 +9,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use cortex_m_semihosting::debug::{exit, EXIT_FAILURE, EXIT_SUCCESS};
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, entry as _};
@@ -20,8 +21,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/util_ipc/async_transaction/target.rs b/target/ast10x0/tests/util_ipc/async_transaction/target.rs
index 022a30193..6c82afb58 100644
--- a/target/ast10x0/tests/util_ipc/async_transaction/target.rs
+++ b/target/ast10x0/tests/util_ipc/async_transaction/target.rs
@@ -10,6 +10,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use console_backend::console_backend_write_all;
 use entry as _;
 use target_common::{declare_target, TargetInterface};
@@ -21,8 +22,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/earlgrey/syscall_latency/target.rs b/target/earlgrey/syscall_latency/target.rs
index 0f76c1ab8..ce3f87c2f 100644
--- a/target/earlgrey/syscall_latency/target.rs
+++ b/target/earlgrey/syscall_latency/target.rs
@@ -3,6 +3,7 @@
 #![no_std]
 #![no_main]
 
+use arch_riscv::Arch;
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, entry as _, kernel as _};
 
@@ -13,7 +14,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/earlgrey/tests/drivers/gpio/target.rs b/target/earlgrey/tests/drivers/gpio/target.rs
index 36a559e20..39d864ec5 100644
--- a/target/earlgrey/tests/drivers/gpio/target.rs
+++ b/target/earlgrey/tests/drivers/gpio/target.rs
@@ -3,6 +3,7 @@
 
 #![no_std]
 #![no_main]
+use arch_riscv::Arch;
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, entry as _};
 
@@ -13,7 +14,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 }
 
diff --git a/target/earlgrey/tests/ipc/user/target.rs b/target/earlgrey/tests/ipc/user/target.rs
index 44a18258d..0cc2c03ba 100644
--- a/target/earlgrey/tests/ipc/user/target.rs
+++ b/target/earlgrey/tests/ipc/user/target.rs
@@ -3,6 +3,7 @@
 
 #![no_std]
 #![no_main]
+use arch_riscv::Arch;
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, entry as _};
 
@@ -13,7 +14,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/earlgrey/tests/uart/target.rs b/target/earlgrey/tests/uart/target.rs
index 2e253d37f..6900744a7 100644
--- a/target/earlgrey/tests/uart/target.rs
+++ b/target/earlgrey/tests/uart/target.rs
@@ -3,6 +3,7 @@
 
 #![no_std]
 #![no_main]
+use arch_riscv::Arch;
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, entry as _};
 
@@ -13,7 +14,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/veer/ipc/user/target.rs b/target/veer/ipc/user/target.rs
index bf55cb397..62e1eb099 100644
--- a/target/veer/ipc/user/target.rs
+++ b/target/veer/ipc/user/target.rs
@@ -3,6 +3,7 @@
 #![no_std]
 #![no_main]
 
+use arch_riscv::Arch;
 use console_backend as _;
 use entry::exit;
 use target_common::{declare_target, TargetInterface};
@@ -14,7 +15,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/veer/syscall_latency/target.rs b/target/veer/syscall_latency/target.rs
index 5f4ddbf1b..8d27029b3 100644
--- a/target/veer/syscall_latency/target.rs
+++ b/target/veer/syscall_latency/target.rs
@@ -3,6 +3,7 @@
 #![no_std]
 #![no_main]
 
+use arch_riscv::Arch;
 use entry::exit;
 use target_common::{declare_target, TargetInterface};
 use {console_backend as _, kernel as _};
@@ -14,7 +15,12 @@ impl TargetInterface for Target {
 
     fn main() -> ! {
         codegen::start();
-        loop {}
+        // The bootstrap thread has nothing left to do. Sleep rather than spin: a
+        // spinning thread at the same priority as the app threads takes a time
+        // slice at every scheduler tick and delays every wake-up behind it.
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {

From f9377af8dedfdfa0647b7a54ee75780e03e1b465 Mon Sep 17 00:00:00 2001
From: JesseMelon <jessechambers2000@icloud.com>
Date: Tue, 27 Oct 2026 16:19:30 -0400
Subject: [PATCH 2/3] additional targets

---
 target/ast10x0/tests/mctp/server/target.rs                   | 4 +++-
 target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs     | 5 +++--
 .../ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs | 5 +++--
 target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs | 5 +++--
 target/ast10x0/tests/spdm/auth/target.rs                     | 4 +++-
 target/ast10x0/tests/spdm/vca/target.rs                      | 4 +++-
 6 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/target/ast10x0/tests/mctp/server/target.rs b/target/ast10x0/tests/mctp/server/target.rs
index ed4f0348e..323d98e19 100644
--- a/target/ast10x0/tests/mctp/server/target.rs
+++ b/target/ast10x0/tests/mctp/server/target.rs
@@ -46,7 +46,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs b/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
index 09133de81..8bf9b79ec 100644
--- a/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
+++ b/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
@@ -24,8 +24,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs b/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
index 60163ddd6..598ba7e84 100644
--- a/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
+++ b/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
@@ -37,8 +37,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs b/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
index 6524fdcf6..b9af8432e 100644
--- a/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
+++ b/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
@@ -33,8 +33,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        #[expect(clippy::empty_loop)]
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/spdm/auth/target.rs b/target/ast10x0/tests/spdm/auth/target.rs
index 42dd70db1..0b23c424f 100644
--- a/target/ast10x0/tests/spdm/auth/target.rs
+++ b/target/ast10x0/tests/spdm/auth/target.rs
@@ -46,7 +46,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {
diff --git a/target/ast10x0/tests/spdm/vca/target.rs b/target/ast10x0/tests/spdm/vca/target.rs
index 665fd6556..661e649f3 100644
--- a/target/ast10x0/tests/spdm/vca/target.rs
+++ b/target/ast10x0/tests/spdm/vca/target.rs
@@ -46,7 +46,9 @@ impl TargetInterface for Target {
         }
 
         codegen::start();
-        loop {}
+        loop {
+            let _ = kernel::sleep_until(Arch, kernel::Instant::MAX);
+        }
     }
 
     fn shutdown(code: u32) -> ! {

From 860b832706156ce670a058cb0ad1469a648c2440 Mon Sep 17 00:00:00 2001
From: JesseMelon <jessechambers2000@icloud.com>
Date: Wed, 28 Oct 2026 11:59:16 -0400
Subject: [PATCH 3/3] targets: fix missing Arch import for bootstrap sleep

---
 target/ast10x0/tests/mctp/server/target.rs                      | 1 +
 target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs        | 1 +
 target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs | 1 +
 target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs    | 1 +
 target/ast10x0/tests/spdm/auth/target.rs                        | 1 +
 target/ast10x0/tests/spdm/vca/target.rs                         | 1 +
 6 files changed, 6 insertions(+)

diff --git a/target/ast10x0/tests/mctp/server/target.rs b/target/ast10x0/tests/mctp/server/target.rs
index 323d98e19..cd3ad5fd9 100644
--- a/target/ast10x0/tests/mctp/server/target.rs
+++ b/target/ast10x0/tests/mctp/server/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_board::{Ast10x0Board, Ast10x0BoardDescriptor, I2cBusCfg};
 use ast10x0_peripherals::i2c::{ClockConfig, I2cConfig, I2cSpeed, I2cXferMode};
 use ast10x0_peripherals::scu::pinctrl;
diff --git a/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs b/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
index 8bf9b79ec..cb8b234f4 100644
--- a/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
+++ b/target/ast10x0/tests/peripherals/gpio/gpio_irq/target.rs
@@ -6,6 +6,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_peripherals::scu::{pinctrl, ScuRegisters};
 use console_backend::console_backend_write_all;
 use entry as _;
diff --git a/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs b/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
index 598ba7e84..e4c1e5cef 100644
--- a/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
+++ b/target/ast10x0/tests/peripherals/i2c/i2c_slave_rx_ipc/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_peripherals::i2c;
 use ast10x0_peripherals::scu::pinctrl;
 use console_backend::console_backend_write_all;
diff --git a/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs b/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
index b9af8432e..7a491562e 100644
--- a/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
+++ b/target/ast10x0/tests/peripherals/sgpiom/sgpiom_irq/target.rs
@@ -15,6 +15,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_peripherals::scu::{pinctrl, ScuRegisters};
 use console_backend::console_backend_write_all;
 use entry as _;
diff --git a/target/ast10x0/tests/spdm/auth/target.rs b/target/ast10x0/tests/spdm/auth/target.rs
index 0b23c424f..93a0c49b0 100644
--- a/target/ast10x0/tests/spdm/auth/target.rs
+++ b/target/ast10x0/tests/spdm/auth/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_board::{Ast10x0Board, Ast10x0BoardDescriptor, I2cBusCfg};
 use ast10x0_peripherals::i2c::{ClockConfig, I2cConfig, I2cSpeed, I2cXferMode};
 use ast10x0_peripherals::scu::pinctrl;
diff --git a/target/ast10x0/tests/spdm/vca/target.rs b/target/ast10x0/tests/spdm/vca/target.rs
index 661e649f3..f55a808e7 100644
--- a/target/ast10x0/tests/spdm/vca/target.rs
+++ b/target/ast10x0/tests/spdm/vca/target.rs
@@ -4,6 +4,7 @@
 #![no_std]
 #![no_main]
 
+use arch_arm_cortex_m::Arch;
 use ast10x0_board::{Ast10x0Board, Ast10x0BoardDescriptor, I2cBusCfg};
 use ast10x0_peripherals::i2c::{ClockConfig, I2cConfig, I2cSpeed, I2cXferMode};
 use ast10x0_peripherals::scu::pinctrl;