From 053aa8ff8006427abe89afc0df944a201d424af2 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@eecs.berkeley.edu>
Date: Tue, 3 Jun 2014 11:06:38 -0700
Subject: Turn off interrupts when talking to host

---
 pk/atomic.h   | 14 ++++++++++++++
 pk/frontend.c |  4 ++--
 2 files changed, 16 insertions(+), 2 deletions(-)

(limited to 'pk')

diff --git a/pk/atomic.h b/pk/atomic.h
index 8e80c78..fea1330 100644
--- a/pk/atomic.h
+++ b/pk/atomic.h
@@ -4,6 +4,7 @@
 #define _RISCV_ATOMIC_H
 
 #include "config.h"
+#include "encoding.h"
 
 typedef struct { volatile long val; } atomic_t;
 typedef struct { atomic_t lock; } spinlock_t;
@@ -71,4 +72,17 @@ static inline void spinlock_unlock(spinlock_t* lock)
   atomic_set(&lock->lock,0);
 }
 
+static inline long spinlock_lock_irqsave(spinlock_t* lock)
+{
+  long flags = clear_csr(status, SR_EI);
+  spinlock_lock(lock);
+  return flags;
+}
+
+static inline void spinlock_unlock_irqrestore(spinlock_t* lock, long flags)
+{
+  spinlock_unlock(lock);
+  set_csr(status, flags & SR_EI);
+}
+
 #endif
diff --git a/pk/frontend.c b/pk/frontend.c
index 4c6051e..7bf4710 100644
--- a/pk/frontend.c
+++ b/pk/frontend.c
@@ -10,7 +10,7 @@ long frontend_syscall(long n, long a0, long a1, long a2, long a3, long a4)
   static volatile uint64_t magic_mem[8];
 
   static spinlock_t lock = SPINLOCK_INIT;
-  spinlock_lock(&lock);
+  long irq = spinlock_lock_irqsave(&lock);
 
   magic_mem[0] = n;
   magic_mem[1] = a0;
@@ -28,6 +28,6 @@ long frontend_syscall(long n, long a0, long a1, long a2, long a3, long a4)
 
   long ret = magic_mem[0];
 
-  spinlock_unlock(&lock);
+  spinlock_unlock_irqrestore(&lock, irq);
   return ret;
 }
-- 
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