Subject: Re: [PATCH v2 10/17] powerpc/mm: Merge vsid calculation in hash_page() and copro_data_segment()

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 01 Oct 2014 15:25:27 +0530

Michael Neuling <[email-masked]> writes:

> From: Ian Munsie <[email-masked]>
>
> The vsid calculation between hash_page() and copro_data_segment() are very
> similar.  This merges these two different versions.
>
> Signed-off-by: Ian Munsie <[email-masked]>
> Signed-off-by: Michael Neuling <[email-masked]>
> ---
>  arch/powerpc/include/asm/mmu-hash64.h |  2 ++
>  arch/powerpc/mm/copro_fault.c         | 45 ++++++--------------------
>  arch/powerpc/mm/hash_utils_64.c       | 61 ++++++++++++++++++++++-------------
>  3 files changed, 50 insertions(+), 58 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
> index f84e5a5..bf43fb0 100644
> --- a/arch/powerpc/include/asm/mmu-hash64.h
> +++ b/arch/powerpc/include/asm/mmu-hash64.h
> @@ -322,6 +322,8 @@ extern int __hash_page_64K(unsigned long ea, unsigned long access,
>  			   unsigned int local, int ssize);
>  struct mm_struct;
>  unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap);
> +int calculate_vsid(struct mm_struct *mm, u64 ea,
> +		   u64 *vsid, int *psize, int *ssize);
>  extern int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, unsigned long trap);
>  extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap);
>  int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
> diff --git a/arch/powerpc/mm/copro_fault.c b/arch/powerpc/mm/copro_fault.c
> index 939abdf..ba8bf8e 100644
> --- a/arch/powerpc/mm/copro_fault.c
> +++ b/arch/powerpc/mm/copro_fault.c
> @@ -94,45 +94,18 @@ EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
>  
>  int copro_data_segment(struct mm_struct *mm, u64 ea, u64 *esid, u64 *vsid)
>  {
> -	int psize, ssize;
> +	int psize, ssize, rc;
>  
>  	*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
> -		ssize = user_segment_size(ea);
> -		*vsid = (get_vsid(mm->context.id, ea, ssize)
> -			 << slb_vsid_shift(ssize)) | SLB_VSID_USER;
> -		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;
> -		ssize = mmu_kernel_ssize;
> -		*vsid = (get_kernel_vsid(ea, mmu_kernel_ssize)
> -			 << SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
> -		break;
> -	case KERNEL_REGION_ID:
> -		pr_devel("copro_data_segment: 0x%llx -- KERNEL_REGION_ID\n", ea);
> -		psize = mmu_linear_psize;
> -		ssize = mmu_kernel_ssize;
> -		*vsid = (get_kernel_vsid(ea, mmu_kernel_ssize)
> -			 << SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
> -		break;
> -	default:
> -		/* Future: support kernel segments so that drivers can use the
> -		 * CoProcessors */
> -		pr_debug("invalid region access at %016llx\n", ea);
> -		return 1;
> -	}
> +	rc = calculate_vsid(mm, ea, vsid, &psize, &ssize);
> +	if (rc)
> +		return rc;
> +	if (REGION_ID(ea) == USER_REGION_ID)
> +		*vsid = (*vsid << slb_vsid_shift(ssize)) | SLB_VSID_USER;
> +	else
> +		*vsid = (*vsid << SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
> +
>  	*vsid |= mmu_psize_defs[psize].sllp |
>  		((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);
>  
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index 0a5c8c0..3fa81ca 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -983,6 +983,38 @@ static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
>  	}
>  }
>  
> +int calculate_vsid(struct mm_struct *mm, u64 ea,
> +		   u64 *vsid, int *psize, int *ssize)
> +{
> +	switch (REGION_ID(ea)) {
> +	case USER_REGION_ID:
> +		pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
> +		*psize = get_slice_psize(mm, ea);
> +		*ssize = user_segment_size(ea);
> +		*vsid = get_vsid(mm->context.id, ea, *ssize);
> +		return 0;
> +	case VMALLOC_REGION_ID:
> +		pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
> +		if (ea < VMALLOC_END)
> +			*psize = mmu_vmalloc_psize;
> +		else
> +			*psize = mmu_io_psize;
> +		*ssize = mmu_kernel_ssize;
> +		*vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
> +		return 0;
> +	case KERNEL_REGION_ID:
> +		pr_devel("%s: 0x%llx -- KERNEL_REGION_ID\n", __func__, ea);
> +		*psize = mmu_linear_psize;
> +		*ssize = mmu_kernel_ssize;
> +		*vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
> +		return 0;
> +	default:
> +		pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
> +		return 1;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(calculate_vsid);
> +
>  /* Result code is:
>   *  0 - handled
>   *  1 - normal page fault
> @@ -993,7 +1025,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, u
>  {
>  	enum ctx_state prev_state = exception_enter();
>  	pgd_t *pgdir;
> -	unsigned long vsid;
> +	u64 vsid;
>  	pte_t *ptep;
>  	unsigned hugeshift;
>  	const struct cpumask *tmp;
> @@ -1003,35 +1035,20 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, u
>  	DBG_LOW("%s(ea=%016lx, access=%lx, trap=%lx\n",
>  		__func__, ea, access, trap);
>  
> -	/* Get region & vsid */
> - 	switch (REGION_ID(ea)) {
> -	case USER_REGION_ID:
> +	/* Get region */
> +	if (REGION_ID(ea) == USER_REGION_ID) {
>  		user_region = 1;
>  		if (! mm) {
>  			DBG_LOW(" user region with no mm !\n");
>  			rc = 1;
>  			goto bail;
>  		}
> -		psize = get_slice_psize(mm, ea);
> -		ssize = user_segment_size(ea);
> -		vsid = get_vsid(mm->context.id, ea, ssize);
> -		break;
> -	case VMALLOC_REGION_ID:
> +	} else
>  		mm = &init_mm;
> -		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
> -		if (ea < VMALLOC_END)
> -			psize = mmu_vmalloc_psize;
> -		else
> -			psize = mmu_io_psize;
> -		ssize = mmu_kernel_ssize;
> -		break;
> -	default:
> -		/* Not a valid range
> -		 * Send the problem up to do_page_fault 
> -		 */
> -		rc = 1;

That part is different now. We now handle kernel_region_id in case of
hash_page. Earlier we used consider it a problem. 

> +	rc = calculate_vsid(mm, ea, &vsid, &psize, &ssize);
> +	if (rc)
>  		goto bail;
> -	}
> +
>  	DBG_LOW(" mm=%p, mm->pgdir=%p, vsid=%016lx\n", mm, mm->pgd, vsid);
>  
>  	/* Bad address. */
> -- 
> 1.9.1
>
> --
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