From 610fd5b3db221e86105add28e1e90bb59111dd41 Mon Sep 17 00:00:00 2001
From: Yuhao Zhou <miskcoo@gmail.com>
Date: Sat, 6 Apr 2019 01:01:10 +0800
Subject: [PATCH] Fix MIPS registers access in backtrace.rs.

---
 kernel/src/arch/mipsel/context.rs | 3 +--
 kernel/src/backtrace.rs           | 6 +++---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/src/arch/mipsel/context.rs b/kernel/src/arch/mipsel/context.rs
index 1a53b7d..000b106 100644
--- a/kernel/src/arch/mipsel/context.rs
+++ b/kernel/src/arch/mipsel/context.rs
@@ -156,8 +156,7 @@ impl Context {
     /// Push all callee-saved registers at the current kernel stack.
     /// Store current sp, switch to target.
     /// Pop all callee-saved registers, then return to the target.
-    #[naked]
-    #[inline(never)]
+    #[inline(always)]
     pub unsafe extern fn switch(&mut self, _target: &mut Self) {
         extern {
             fn switch_context(src : &mut Context, dst : &mut Context);
diff --git a/kernel/src/backtrace.rs b/kernel/src/backtrace.rs
index 5d84f7f..8d6c178 100644
--- a/kernel/src/backtrace.rs
+++ b/kernel/src/backtrace.rs
@@ -24,8 +24,8 @@ pub fn fp() -> usize {
     }
     #[cfg(any(target_arch = "mips"))]
     unsafe {
-        // fp = $30
-        asm!("ori $0, $$$30, 0" : "=r"(ptr));
+        // fp = s8 = $30
+        asm!("ori $0, $$$1, 0" : "=r"(ptr): "i"(30));
     }
 
     ptr
@@ -51,7 +51,7 @@ pub fn lr() -> usize {
 
     #[cfg(target_arch = "mips")]
     unsafe {
-        asm!("ori $0, $$$31, 0" : "=r"(ptr));
+        asm!("ori $0, $$$1, 0" : "=r"(ptr) : "i"(31));
     }
 
     ptr