From 14364e09c6600b1c4bdbdd90ce213ca3b2446bd7 Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Fri, 8 Mar 2024 18:29:10 +0800
Subject: [PATCH] ensure compliance with unsafe conditions on
 exit_blocking_call()

---
 kernel/src/arch/riscv/irq.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/src/arch/riscv/irq.rs b/kernel/src/arch/riscv/irq.rs
index a3ed05b91..c3f5f1cc9 100644
--- a/kernel/src/arch/riscv/irq.rs
+++ b/kernel/src/arch/riscv/irq.rs
@@ -310,8 +310,10 @@ pub extern "C" fn trap_handler(
 
         RiscvException::InstructionPageFault(RETURN_FROM_SWAPPER, _offset) => {
             // Cleanup after the swapper
-            let response =
-                Swap::with_mut(|s| s.exit_blocking_call()).unwrap_or_else(xous_kernel::Result::Error);
+            let response = Swap::with_mut(|s|
+                // safety: this is safe because on return from swapper, we're in the swapper's memory space.
+                unsafe { s.exit_blocking_call() })
+            .unwrap_or_else(xous_kernel::Result::Error);
             // Resume like we're returning from a syscall.
             enable_all_irqs();
             ArchProcess::with_current_mut(|p| {