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

Aneesh Kumar K.V
2014-09-29T08:31:00Z

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() ?

>
> /*
> * 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)

> + 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.

> +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