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-rw-r--r--arch/x86/include/asm/io.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 294cd2a408..1d60427379 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -42,6 +42,7 @@
#include <asm/early_ioremap.h>
#include <asm/pgtable_types.h>
#include <asm/shared/io.h>
+#include <asm/special_insns.h>
#define build_mmio_read(name, size, type, reg, barrier) \
static inline type name(const volatile void __iomem *addr) \
@@ -209,6 +210,23 @@ void memset_io(volatile void __iomem *, int, size_t);
#define memcpy_toio memcpy_toio
#define memset_io memset_io
+#ifdef CONFIG_X86_64
+/*
+ * Commit 0f07496144c2 ("[PATCH] Add faster __iowrite32_copy routine for
+ * x86_64") says that circa 2006 rep movsl is noticeably faster than a copy
+ * loop.
+ */
+static inline void __iowrite32_copy(void __iomem *to, const void *from,
+ size_t count)
+{
+ asm volatile("rep ; movsl"
+ : "=&c"(count), "=&D"(to), "=&S"(from)
+ : "0"(count), "1"(to), "2"(from)
+ : "memory");
+}
+#define __iowrite32_copy __iowrite32_copy
+#endif
+
/*
* ISA space is 'always mapped' on a typical x86 system, no need to
* explicitly ioremap() it. The fact that the ISA IO space is mapped