From: Vivek Goyal <[EMAIL PROTECTED]>

EFER varies like %cr4 depending on the cpu capabilities, and which cpu
capabilities we want to make use of.  So save/restore it make certain
we have the same EFER value when we are done.

Signed-off-by: Eric W. Biederman <[EMAIL PROTECTED]>
Signed-off-by: Vivek Goyal <[EMAIL PROTECTED]>
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>

---

 arch/x86_64/kernel/suspend.c |    3 ++-
 include/asm-x86_64/suspend.h |    1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

Index: linux/arch/x86_64/kernel/suspend.c
===================================================================
--- linux.orig/arch/x86_64/kernel/suspend.c
+++ linux/arch/x86_64/kernel/suspend.c
@@ -33,7 +33,6 @@ void __save_processor_state(struct saved
        asm volatile ("str %0"  : "=m" (ctxt->tr));
 
        /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
-       /* EFER should be constant for kernel version, no need to handle it. */
        /*
         * segment registers
         */
@@ -50,6 +49,7 @@ void __save_processor_state(struct saved
        /*
         * control registers 
         */
+       rdmsrl(MSR_EFER, ctxt->efer);
        asm volatile ("movq %%cr0, %0" : "=r" (ctxt->cr0));
        asm volatile ("movq %%cr2, %0" : "=r" (ctxt->cr2));
        asm volatile ("movq %%cr3, %0" : "=r" (ctxt->cr3));
@@ -75,6 +75,7 @@ void __restore_processor_state(struct sa
        /*
         * control registers
         */
+       wrmsrl(MSR_EFER, ctxt->efer);
        asm volatile ("movq %0, %%cr8" :: "r" (ctxt->cr8));
        asm volatile ("movq %0, %%cr4" :: "r" (ctxt->cr4));
        asm volatile ("movq %0, %%cr3" :: "r" (ctxt->cr3));
Index: linux/include/asm-x86_64/suspend.h
===================================================================
--- linux.orig/include/asm-x86_64/suspend.h
+++ linux/include/asm-x86_64/suspend.h
@@ -17,6 +17,7 @@ struct saved_context {
        u16 ds, es, fs, gs, ss;
        unsigned long gs_base, gs_kernel_base, fs_base;
        unsigned long cr0, cr2, cr3, cr4, cr8;
+       unsigned long efer;
        u16 gdt_pad;
        u16 gdt_limit;
        unsigned long gdt_base;
-
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