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

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Message-ID: <1411083956.12154.29.camel@ale.ozlabs.ibm.com>
Date:	Fri, 19 Sep 2014 09:45:56 +1000
From:	Michael Neuling <mikey@...ling.org>
To:	Jeremy Kerr <jk@...abs.org>
Cc:	greg@...ah.com, arnd@...db.de, mpe@...erman.id.au,
	benh@...nel.crashing.org, anton@...ba.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org,
	imunsie@...ibm.com, cbe-oss-dev@...ts.ozlabs.org
Subject: Re: [PATCH 02/15] powerpc/cell: Move data segment faulting code out
 of cell platform

> > +
> > +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
> > +		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;
> 
> A bit of a nitpick, but how about you remove the repeated:
> 
> 		| (<size> == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0)
> 
> then set ssize in each of the switch cases (like we do with psize), and
> or-in the VSID_B_1T bit at the end:
> 	
> 	*vsid |= mmu_psize_defs[psize].sllp
> 		| (ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);

Nice.  I think below is what you mean.

I'll fold this into the existing patch and repost in a few days.

Thanks,
Mikey

diff --git a/arch/powerpc/mm/copro_fault.c b/arch/powerpc/mm/copro_fault.c
index 4105a63..939caf6 100644
--- a/arch/powerpc/mm/copro_fault.c
+++ b/arch/powerpc/mm/copro_fault.c
@@ -107,8 +107,7 @@ int copro_data_segment(struct mm_struct *mm, u64 ea, u64 *esid, u64 *vsid)
 #endif
 		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);
+			 << slb_vsid_shift(ssize)) | SLB_VSID_USER;
 		break;
 	case VMALLOC_REGION_ID:
 		pr_devel("copro_data_segment: 0x%llx -- VMALLOC_REGION_ID\n", ea);
@@ -116,16 +115,16 @@ int copro_data_segment(struct mm_struct *mm, u64 ea, u64 *esid, u64 *vsid)
 			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
-			| (mmu_kernel_ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);
+			 << 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
-			| (mmu_kernel_ssize == MMU_SEGSIZE_1T ? SLB_VSID_B_1T : 0);
+			 << SLB_VSID_SHIFT) | SLB_VSID_KERNEL;
 		break;
 	default:
 		/* Future: support kernel segments so that drivers can use the
@@ -133,7 +132,8 @@ int copro_data_segment(struct mm_struct *mm, u64 ea, u64 *esid, u64 *vsid)
 		pr_debug("invalid region access at %016llx\n", ea);
 		return 1;
 	}
-	*vsid |= mmu_psize_defs[psize].sllp;
+	*vsid |= mmu_psize_defs[psize].sllp |
+		(ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0;
 
 	return 0;
 }

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