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

Michael Neuling
2014-09-30T04:40:31Z

On Mon, 2014-09-29 at 14:00 +0530, Aneesh Kumar K.V wrote:
> Michael Neuling <mikey@neuling.org> writes:
>
> > From: Ian Munsie <imunsie@au1.ibm.com>
> >
> > __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@au1.ibm.com>
> > Signed-off-by: Michael Neuling <mikey@neuling.org>
> > ---
> > 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
>