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authorH. Peter Anvin <hpa@zytor.com>2008-09-04 08:08:42 -0700
committerH. Peter Anvin <hpa@zytor.com>2008-09-04 08:08:42 -0700
commit7203781c98ad9147564d327de6f6513ad8fc0f4e (patch)
tree5c29a2a04a626bf08a0d56fd8a0068b3c92ad284 /include/asm-x86/processor.h
parent671eef85a3e885dff4ce210d8774ad50a91d5967 (diff)
parentaf2e1f276ff08f17192411ea3b71c13a758dfe12 (diff)
Merge branch 'x86/cpu' into x86/core
Conflicts: arch/x86/kernel/cpu/feature_names.c include/asm-x86/cpufeature.h
Diffstat (limited to 'include/asm-x86/processor.h')
-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 6d5648945eb..10471cfab14 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -732,6 +732,29 @@ 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);