x86, msr: change msr-reg.o to obj-y, and export its symbols

Change msr-reg.o to obj-y (it will be included in virtually every
kernel since it is used by the initialization code for AMD processors)
and add a separate C file to export its symbols to modules, so that
msr.ko can use them; on uniprocessors we bypass the helper functions
in msr.o and use the accessor functions directly via inlines.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <20090904140834.GA15789@elte.hu>
Cc: Borislav Petkov <petkovbb@googlemail.com>

arch/x86/lib/Makefile

@@ -8,7 +8,8 @@ lib-y := delay.o
 lib-y += thunk_$(BITS).o
 lib-y += usercopy_$(BITS).o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
-lib-y += msr-reg.o
+
+obj-y += msr-reg.o msr-reg-export.o
 
 ifeq ($(CONFIG_X86_32),y)
         obj-y += atomic64_32.o

arch/x86/lib/msr-reg-export.c

+#include <linux/module.h>
+#include <asm/msr.h>
+
+EXPORT_SYMBOL(native_rdmsr_safe_regs);
+EXPORT_SYMBOL(native_wrmsr_safe_regs);