From fa067f11371c9e27ccf13ffcb7c8a29989e17499 Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Sun, 22 Dec 2024 00:32:40 +0800
Subject: [PATCH] retrofit swapper so that its print function can be selected
 out

so that we can share app uart with other processes that need it for debug
---
 services/xous-swapper/Cargo.toml   | 6 ++++--
 services/xous-swapper/src/debug.rs | 6 +++---
 services/xous-swapper/src/main.rs  | 6 +++---
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/services/xous-swapper/Cargo.toml b/services/xous-swapper/Cargo.toml
index 0c0ca0532..0367662df 100644
--- a/services/xous-swapper/Cargo.toml
+++ b/services/xous-swapper/Cargo.toml
@@ -40,7 +40,9 @@ renode = ["utralib/renode"]
 swap-userspace-testing = []
 oom-doom = []
 
-debug-print = [
-] # mutually exclusive feature with other crates that use the app UART
+# mutually exclusive feature with other crates that use the app UART
+# requires "userspace-debug" to be passed to the loader for this to work.
+debug-print-swapper = []
+
 debug-verbose = []
 default = []
diff --git a/services/xous-swapper/src/debug.rs b/services/xous-swapper/src/debug.rs
index e44834b01..33992fd84 100644
--- a/services/xous-swapper/src/debug.rs
+++ b/services/xous-swapper/src/debug.rs
@@ -2,7 +2,7 @@ use core::fmt::{Error, Write};
 
 pub struct DebugUart {}
 impl DebugUart {
-    #[cfg(all(feature = "debug-print", any(feature = "precursor", feature = "renode")))]
+    #[cfg(all(feature = "debug-print-swapper", any(feature = "precursor", feature = "renode")))]
     pub fn putc(&mut self, c: u8) {
         use utralib::generated::*;
         let mut csr = CSR::new(loader::swap::SWAP_APP_UART_VADDR as *mut u32);
@@ -12,7 +12,7 @@ impl DebugUart {
         csr.wfo(utra::app_uart::RXTX_RXTX, c as u32);
     }
 
-    #[cfg(all(feature = "debug-print", any(feature = "cramium-soc")))]
+    #[cfg(all(feature = "debug-print-swapper", any(feature = "cramium-soc")))]
     pub fn putc(&mut self, c: u8) {
         use cramium_hal::udma;
         // safety: safe to call as long as the raw parts are initialized and we exclusively
@@ -30,7 +30,7 @@ impl DebugUart {
         uart.write(&[c]);
     }
 
-    #[cfg(not(feature = "debug-print"))]
+    #[cfg(not(feature = "debug-print-swapper"))]
     pub fn putc(&self, _c: u8) {}
 }
 
diff --git a/services/xous-swapper/src/main.rs b/services/xous-swapper/src/main.rs
index 9f56c2858..aa6058485 100644
--- a/services/xous-swapper/src/main.rs
+++ b/services/xous-swapper/src/main.rs
@@ -330,7 +330,7 @@ fn write_to_swap_inner(
     };
 
     // step 2: write the page to swap
-    #[cfg(feature = "debug-print")]
+    #[cfg(feature = "debug-print-swapper")]
     writeln!(DebugUart {}, "WTS PID{} VA {:x}", candidate.raw_pid(), candidate.vaddr()).ok();
     // this is safe because the page is aligned and initialized as it comes from the kernel
     // remember that this page is overwritten with encrypted data
@@ -448,7 +448,7 @@ fn swap_handler(
 
         // swapper is not allowed to use `log` for debugging under most circumstances, because
         // the swapper can't send messages when handling a swap call. Instead, we use a local
-        // debug UART to handle this. This needs to be enabled with the "debug-print" feature
+        // debug UART to handle this. This needs to be enabled with the "debug-print-swapper" feature
         // and is mutually exclusive with the "gdb-stub" feature in the kernel since it uses
         // the same physical hardware.
         sss.inner = Some(SwapperSharedState {
@@ -507,7 +507,7 @@ fn swap_handler(
             };
             // clear the used bit in swap
             ss.sct.counts[paddr_in_swap / PAGE_SIZE] &= !loader::FLG_SWAP_USED;
-            #[cfg(feature = "debug-print")]
+            #[cfg(feature = "debug-print-swapper")]
             writeln!(
                 DebugUart {},
                 "RFS PID{} VA {:x} PA {:x} counts {:x}",