From: Ben Pfaff <blp@cs.stanford.edu>
Date: Sun, 10 Oct 2004 23:56:14 +0000 (+0000)
Subject: Add volatile to asm statement in intr_get_level(),
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=commitdiff_plain;h=e80b8a193eb5fcafc08dfab7a9c2ef274a274eca

Add volatile to asm statement in intr_get_level(),
otherwise GCC will assume that two calls to this function can be
optimized into one, even across asm("sti") or asm("cli").
---

diff --git a/src/threads/interrupt.c b/src/threads/interrupt.c
index 8e7d575..3637b00 100644
--- a/src/threads/interrupt.c
+++ b/src/threads/interrupt.c
@@ -51,7 +51,7 @@ intr_get_level (void)
 {
   uint32_t flags;
   
-  asm ("pushfl; popl %0" : "=g" (flags));
+  asm volatile ("pushfl; popl %0" : "=g" (flags));
 
   return flags & FLAG_IF ? INTR_ON : INTR_OFF;
 }