Merge branch 'linus' into x86/x2apic

[sfrench/cifs-2.6.git] / include / asm-x86 / processor.h

diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 79338fe965d28a97d663acacdd9463ab4eb95824..d2bf5fe8f4ffa19923ee68c297786b965ca226ba 100644 (file)
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -729,6 +729,29 @@ extern unsigned long               boot_option_idle_override;
 extern unsigned long           idle_halt;
 extern unsigned long           idle_nomwait;
 
+/*
+ * on systems with caches, caches must be flashed as the absolute
+ * last instruction before going into a suspended halt.  Otherwise,
+ * dirty data can linger in the cache and become stale on resume,
+ * leading to strange errors.
+ *
+ * perform a variety of operations to guarantee that the compiler
+ * will not reorder instructions.  wbinvd itself is serializing
+ * so the processor will not reorder.
+ *
+ * Systems without cache can just go into halt.
+ */
+static inline void wbinvd_halt(void)
+{
+       mb();
+       /* check for clflush to determine if wbinvd is legal */
+       if (cpu_has_clflush)
+               asm volatile("cli; wbinvd; 1: hlt; jmp 1b" : : : "memory");
+       else
+               while (1)
+                       halt();
+}
+
 extern void enable_sep_cpu(void);
 extern int sysenter_setup(void);