Re: [PATCH 02/15] powerpc/cell: Move data segment faulting code out of cell platform

[Michael Neuling]

On Mon, 2014-09-29 at 14:00 +0530, Aneesh Kumar K.V wrote:
> Michael Neuling <mikey@xxxxxxxxxxx> writes:
> 
> > From: Ian Munsie <imunsie@xxxxxxxxxxx>
> >
> > __spu_trap_data_seg() currently contains code to determine the VSID and ESID
> > required for a particular EA and mm struct.
> >
> > This code is generically useful for other co-processors.  This moves the code
> > of the cell platform so it can be used by other powerpc code.
> >
> > Signed-off-by: Ian Munsie <imunsie@xxxxxxxxxxx>
> > Signed-off-by: Michael Neuling <mikey@xxxxxxxxxxx>
> > ---
> >  arch/powerpc/include/asm/mmu-hash64.h  |  2 ++
> >  arch/powerpc/mm/copro_fault.c          | 48 ++++++++++++++++++++++++++++++++++
> >  arch/powerpc/mm/slb.c                  |  3 ---
> >  arch/powerpc/platforms/cell/spu_base.c | 41 +++--------------------------
> >  4 files changed, 54 insertions(+), 40 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
> > index d765144..fd19a53 100644
> > --- a/arch/powerpc/include/asm/mmu-hash64.h
> > +++ b/arch/powerpc/include/asm/mmu-hash64.h
> > @@ -180,6 +180,8 @@ static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
> >   * we work in all cases including 4k page size.
> >   */
> >  #define VPN_SHIFT	12
> > +#define slb_vsid_shift(ssize)	\
> > +	((ssize) == MMU_SEGSIZE_256M ? SLB_VSID_SHIFT : SLB_VSID_SHIFT_1T)
> 
> can it be static inline similar to segment_shift() ?

Yep.

> 
> >  
> >  /*
> >   * HPTE Large Page (LP) details
> > diff --git a/arch/powerpc/mm/copro_fault.c b/arch/powerpc/mm/copro_fault.c
> > index ba7df14..4105a63 100644
> > --- a/arch/powerpc/mm/copro_fault.c
> > +++ b/arch/powerpc/mm/copro_fault.c
> > @@ -90,3 +90,51 @@ out_unlock:
> >  	return ret;
> >  }
> >  EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
> > +
> > +int copro_data_segment(struct mm_struct *mm, u64 ea, u64 *esid, u64 *vsid)
> > +{
> > +	int psize, ssize;
> > +
> > +	*esid = (ea & ESID_MASK) | SLB_ESID_V;
> > +
> > +	switch (REGION_ID(ea)) {
> > +	case USER_REGION_ID:
> > +		pr_devel("copro_data_segment: 0x%llx -- USER_REGION_ID\n", ea);
> > +#ifdef CONFIG_PPC_MM_SLICES
> > +		psize = get_slice_psize(mm, ea);
> > +#else
> > +		psize = mm->context.user_psize;
> > +#endif
> 
> We don't need that.
> 
> #ifdef CONFIG_PPC_STD_MMU_64
> #define get_slice_psize(mm, addr)	((mm)->context.user_psize)

OK

> 
> 
> > +		ssize = user_segment_size(ea);
> > +		*vsid = (get_vsid(mm->context.id, ea, ssize)
> > +			<< slb_vsid_shift(ssize)) | SLB_VSID_USER
> > +			| (ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);
> > +		break;
> > +	case VMALLOC_REGION_ID:
> > +		pr_devel("copro_data_segment: 0x%llx -- VMALLOC_REGION_ID\n", ea);
> > +		if (ea < VMALLOC_END)
> > +			psize = mmu_vmalloc_psize;
> > +		else
> > +			psize = mmu_io_psize;
> > +		*vsid = (get_kernel_vsid(ea, mmu_kernel_ssize)
> > +			<< SLB_VSID_SHIFT) | SLB_VSID_KERNEL
> > +			| (mmu_kernel_ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);
> > +		break;
> > +	case KERNEL_REGION_ID:
> > +		pr_devel("copro_data_segment: 0x%llx -- KERNEL_REGION_ID\n", ea);
> > +		psize = mmu_linear_psize;
> > +		*vsid = (get_kernel_vsid(ea, mmu_kernel_ssize)
> > +			<< SLB_VSID_SHIFT) | SLB_VSID_KERNEL
> > +			| (mmu_kernel_ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);
> > +		break;
> > +	default:
> > +		/* Future: support kernel segments so that drivers can use the
> > +		 * CoProcessors */
> > +		pr_debug("invalid region access at %016llx\n", ea);
> > +		return 1;
> > +	}
> > +	*vsid |= mmu_psize_defs[psize].sllp;
> > +
> > +	return 0;
> > +}
> 
> large part of this is same as what we do in hash_page. And we are not
> really updating vsid here, it is vsid slb encoding. So why not abstract
> the vsid part and use that in hash_page also ? That would have also taken
> care of the above #ifdef.

Ok, I've merge these two variants.

Going to repost this whole series again soon.  I'll be in there.

Thanks for the comments.

Mikey

> 
> > +EXPORT_SYMBOL_GPL(copro_data_segment);
> > diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
> > index 0399a67..6e450ca 100644
> > --- a/arch/powerpc/mm/slb.c
> > +++ b/arch/powerpc/mm/slb.c
> > @@ -46,9 +46,6 @@ static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
> >  	return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | slot;
> >  }
> >  
> > -#define slb_vsid_shift(ssize)	\
> > -	((ssize) == MMU_SEGSIZE_256M? SLB_VSID_SHIFT: SLB_VSID_SHIFT_1T)
> > -
> >  static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
> >  					 unsigned long flags)
> >  {
> > diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
> > index 2930d1e..fe004b1 100644
> > --- a/arch/powerpc/platforms/cell/spu_base.c
> > +++ b/arch/powerpc/platforms/cell/spu_base.c
> > @@ -167,45 +167,12 @@ static inline void spu_load_slb(struct spu *spu, int slbe, struct spu_slb *slb)
> >  
> >  static int __spu_trap_data_seg(struct spu *spu, unsigned long ea)
> >  {
> > -	struct mm_struct *mm = spu->mm;
> >  	struct spu_slb slb;
> > -	int psize;
> > -
> > -	pr_debug("%s\n", __func__);
> > -
> > -	slb.esid = (ea & ESID_MASK) | SLB_ESID_V;
> > +	int ret;
> >  
> > -	switch(REGION_ID(ea)) {
> > -	case USER_REGION_ID:
> > -#ifdef CONFIG_PPC_MM_SLICES
> > -		psize = get_slice_psize(mm, ea);
> > -#else
> > -		psize = mm->context.user_psize;
> > -#endif
> > -		slb.vsid = (get_vsid(mm->context.id, ea, MMU_SEGSIZE_256M)
> > -				<< SLB_VSID_SHIFT) | SLB_VSID_USER;
> > -		break;
> > -	case VMALLOC_REGION_ID:
> > -		if (ea < VMALLOC_END)
> > -			psize = mmu_vmalloc_psize;
> > -		else
> > -			psize = mmu_io_psize;
> > -		slb.vsid = (get_kernel_vsid(ea, MMU_SEGSIZE_256M)
> > -				<< SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
> > -		break;
> > -	case KERNEL_REGION_ID:
> > -		psize = mmu_linear_psize;
> > -		slb.vsid = (get_kernel_vsid(ea, MMU_SEGSIZE_256M)
> > -				<< SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
> > -		break;
> > -	default:
> > -		/* Future: support kernel segments so that drivers
> > -		 * can use SPUs.
> > -		 */
> > -		pr_debug("invalid region access at %016lx\n", ea);
> > -		return 1;
> > -	}
> > -	slb.vsid |= mmu_psize_defs[psize].sllp;
> > +	ret = copro_data_segment(spu->mm, ea, &slb.esid, &slb.vsid);
> > +	if (ret)
> > +		return ret;
> >  
> >  	spu_load_slb(spu, spu->slb_replace, &slb);
> >  
> 
> -aneesh
> 

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