From 0d3c526e866e6160f4bc5a9b8e75c85ead8719ce Mon Sep 17 00:00:00 2001
From: "kaf24@firebug.cl.cam.ac.uk" <kaf24@firebug.cl.cam.ac.uk>
Date: Mon, 28 Mar 2005 21:15:47 +0000
Subject: [PATCH] bitkeeper revision 1.1159.258.73
 (424874035MwIUi8jFNCdaLfnJCrWig)

Fix cpu_relax/rep_nop to include a compiler barrier. This is needed
for SMP booting with gcc 4.0, for example.
Signed-off-by: Keir Fraser <keir@xensource.com>
---
 xen/arch/x86/memory.c           |  5 +----
 xen/arch/x86/setup.c            |  3 ---
 xen/arch/x86/smp.c              | 10 ++--------
 xen/arch/x86/smpboot.c          |  2 +-
 xen/common/schedule.c           |  3 ---
 xen/include/asm-x86/processor.h |  4 ++--
 6 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/xen/arch/x86/memory.c b/xen/arch/x86/memory.c
index 4c91d7374b..e82f5aa8c8 100644
--- a/xen/arch/x86/memory.c
+++ b/xen/arch/x86/memory.c
@@ -904,10 +904,7 @@ int get_page_type(struct pfn_info *page, u32 type)
         {
             /* Someone else is updating validation of this page. Wait... */
             while ( (y = page->u.inuse.type_info) == x )
-            {
-                rep_nop();
-                barrier();
-            }
+                cpu_relax();
             goto again;
         }
     }
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 6ef530c4e6..1de2e2d71d 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -452,10 +452,7 @@ static void __init start_of_day(void)
     smp_threads_ready = 1;
     smp_commence(); /* Tell other CPUs that state of the world is stable. */
     while ( wait_init_idle != 0 )
-    {
         cpu_relax();
-        barrier();
-    }
 #endif
 
     watchdog_on = 1;
diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index 65b126c1e9..120acaef00 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -239,10 +239,7 @@ void flush_tlb_mask(unsigned long mask)
         flush_cpumask = mask;
         send_IPI_mask(mask, INVALIDATE_TLB_VECTOR);
         while ( flush_cpumask != 0 )
-        {
-            rep_nop();
-            barrier();
-        }
+            cpu_relax();
 
         spin_unlock(&flush_lock);
     }
@@ -260,10 +257,7 @@ void new_tlbflush_clock_period(void)
         flush_cpumask = ((1 << smp_num_cpus) - 1) & ~(1 << smp_processor_id());
         send_IPI_allbutself(INVALIDATE_TLB_VECTOR);
         while ( flush_cpumask != 0 )
-        {
-            rep_nop();
-            barrier();
-        }
+            cpu_relax();
         spin_unlock(&flush_lock);
     }
 
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index f5aacca063..e3e152bb49 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -396,7 +396,7 @@ void __init start_secondary(void)
     smp_callin();
 
     while (!atomic_read(&smp_commenced))
-        rep_nop();
+        cpu_relax();
 
     /*
      * At this point, boot CPU has fully initialised the IDT. It is
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 9756b18512..0470f9ee17 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -166,10 +166,7 @@ void domain_sleep(struct domain *d)
  
     /* Synchronous. */
     while ( test_bit(DF_RUNNING, &d->flags) && !domain_runnable(d) )
-    {
-        smp_mb();
         cpu_relax();
-    }
 }
 
 void domain_wake(struct domain *d)
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index e3446aaeae..00b3259f98 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -571,10 +571,10 @@ struct extended_sigtable {
 /* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
 static inline void rep_nop(void)
 {
-    __asm__ __volatile__("rep;nop");
+    __asm__ __volatile__ ( "rep;nop" : : : "memory" );
 }
 
-#define cpu_relax()	rep_nop()
+#define cpu_relax() rep_nop()
 
 /* Prefetch instructions for Pentium III and AMD Athlon */
 #ifdef 	CONFIG_MPENTIUMIII
-- 
2.30.2