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-rw-r--r--include/asm-x86/processor.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 5f58da401b43..4df3e2f6fb56 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -728,6 +728,29 @@ 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);
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