Messages in this thread |  | | | Date | Sat, 18 Nov 2006 01:11:29 +0100 | | From | Pavel Machek <> | | Subject | Re: [PATCH 8/20] x86_64: Add EFER to the set registers saved by save_processor_state |
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Hi!
> 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.
I still think that comment is right: EFER is function(cpu capabilities, kernel version, kernel cmdline); and that _should_ be constant accross suspend.
Anyway saving it does not hurt and code is probably easier to understand.
ACK. Pavel
> /* 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)); > --- linux-2.6.19-rc6-reloc/include/asm-x86_64/suspend.h~x86_64-Add-EFER-to-the-set-registers-saved-by-save_processor_state 2006-11-17 00:08:16.000000000 -0500 > @@ -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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