[PATCH 2/2] powerpc/hibernate: add restore mmu context after resume

[Wang Dongsheng-B40534]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Thursday, July 11, 2013 5:43 AM
> To: Wang Dongsheng-B40534
> Cc: Wang Dongsheng-B40534; benh at kernel.crashing.org; Wood Scott-B07421;
> johannes at sipsolutions.net; anton at enomsg.org; galak at kernel.crashing.org;
> linuxppc-dev at lists.ozlabs.org
> Subject: Re: [PATCH 2/2] powerpc/hibernate: add restore mmu context after
> resume
> 
> On 07/10/2013 05:11:54 AM, Wang Dongsheng-B40534 wrote:
> > Hi scott & ben,
> >
> > About this patch do you have any suggestions?
> >
> > Thanks
> >
> > - dongsheng
> >
> > > -----Original Message-----
> > > From: Wang Dongsheng-B40534
> > > Sent: Sunday, June 09, 2013 6:38 PM
> > > To: benh at kernel.crashing.org
> > > Cc: johannes at sipsolutions.net; anton at enomsg.org; Wood Scott-B07421;
> > > galak at kernel.crashing.org; linuxppc-dev at lists.ozlabs.org; Wang
> > Dongsheng-
> > > B40534
> > > Subject: [PATCH 2/2] powerpc/hibernate: add restore mmu context
> > after
> > > resume
> > >
> > > add restore_mmu_context to replace switch_mmu_context in
> > > restore_processor_state, because the switch_mmu_context will do a
> > > whole pile of stuff that are probably completely unnecessary.
> > >
> > > There just need to restore the existing process context, and
> > > invalidate TLB for boot core.
> > >
> > > Signed-off-by: Wang Dongsheng <dongsheng.wang at freescale.com>
> > > ---
> > >  arch/powerpc/include/asm/tlbflush.h |  2 ++
> > >  arch/powerpc/kernel/swsusp.c        |  4 +---
> > >  arch/powerpc/mm/tlb_nohash.c        | 12 ++++++++++++
> > >  3 files changed, 15 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/arch/powerpc/include/asm/tlbflush.h
> > > b/arch/powerpc/include/asm/tlbflush.h
> > > index 61a5927..c401fe3 100644
> > > --- a/arch/powerpc/include/asm/tlbflush.h
> > > +++ b/arch/powerpc/include/asm/tlbflush.h
> > > @@ -44,6 +44,8 @@ extern void local_flush_tlb_page(struct
> > vm_area_struct
> > > *vma, unsigned long vmadd
> > >  extern void __local_flush_tlb_page(struct mm_struct *mm, unsigned
> > long
> > > vmaddr,
> > >  				   int tsize, int ind);
> > >
> > > +extern void restore_mmu_context(void);
> > > +
> > >  #ifdef CONFIG_SMP
> > >  extern void flush_tlb_mm(struct mm_struct *mm);  extern void
> > > flush_tlb_page(struct vm_area_struct *vma, unsigned
> > long
> > > vmaddr);
> > > diff --git a/arch/powerpc/kernel/swsusp.c
> > b/arch/powerpc/kernel/swsusp.c
> > > index eae33e1..0b104d7 100644
> > > --- a/arch/powerpc/kernel/swsusp.c
> > > +++ b/arch/powerpc/kernel/swsusp.c
> > > @@ -32,7 +32,5 @@ void save_processor_state(void)
> > >
> > >  void restore_processor_state(void)
> > >  {
> > > -#ifdef CONFIG_PPC32
> > > -	switch_mmu_context(current->active_mm, current->active_mm);
> > > -#endif
> > > +	restore_mmu_context();
> > >  }
> > > diff --git a/arch/powerpc/mm/tlb_nohash.c
> > b/arch/powerpc/mm/tlb_nohash.c
> > > index df32a83..a5a0708 100644
> > > --- a/arch/powerpc/mm/tlb_nohash.c
> > > +++ b/arch/powerpc/mm/tlb_nohash.c
> > > @@ -39,10 +39,12 @@
> > >  #include <linux/of_fdt.h>
> > >  #include <linux/hugetlb.h>
> > >
> > > +#include <asm/current.h>
> > >  #include <asm/tlbflush.h>
> > >  #include <asm/tlb.h>
> > >  #include <asm/code-patching.h>
> > >  #include <asm/hugetlb.h>
> > > +#include <asm/mmu_context.h>
> > >
> > >  #include "mmu_decl.h"
> > >
> > > @@ -193,6 +195,16 @@ void local_flush_tlb_page(struct
> > vm_area_struct *vma,
> > > unsigned long vmaddr)
> > >  }
> > >  EXPORT_SYMBOL(local_flush_tlb_page);
> > >
> > > +void restore_mmu_context(void)
> > > +{
> > > +	struct mm_struct *mm = current->active_mm;
> > > +
> > > +	set_context(mm->context.id, mm->pgd);
> > > +
> > > +	_tlbil_all();
> > > +}
> > > +EXPORT_SYMBOL(restore_mmu_context);
> 
> What about targets that don't use tlb_nohash.c?
> 
Yes, you are right, if we used PPC_STD_MMU, compilation error will occur.
And _tlbil_all should be remove, because all of the tlb already invalidated in swsusp_*.S .
So we should invalid tlb in swsusp_asm64.S & swsusp_booke.S on freescale platform.

How about add restore_mmu_context(struct mm_struct* mm) into "arch/powerpc/include/asm/mmu_context.h"

Path: arch/powerpc/include/asm/mmu_context.h
static void restore_mmu_context(struct mm_struct *mm)
{
       set_context(mm->context.id, mm->pgd);
}

> -Scott