Add EFER to the register set saved by save_processor_state From: Vivek Goyal 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 Signed-off-by: Vivek Goyal Signed-off-by: Andi Kleen --- 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;