[PATCH v2 1/4] powerpc/mm: Respect _PAGE_COHERENT on classic ppc32 SW TLB load machines

[Kumar Gala <galak@kernel.crashing.org>]

Since we now set _PAGE_COHERENT in the Linux PTE we shouldn't be clearing
it out before we setup the SW TLB.  Today all the SW TLB machines
(603/e300) that we support are non-SMP, however there are some errata on
some devices that cause us to set _PAGE_COHERENT via CPU_FTR_NEED_COHERENT.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---

* We need to respect how CPU_FTR_NEED_COHERENT is set

 arch/powerpc/kernel/head_32.S |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index f8c2e6b..d0bad4b 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -514,8 +514,11 @@ InstructionTLBMiss:
 	and	r1,r1,r2		/* writable if _RW and _DIRTY */
 	rlwimi	r3,r3,32-1,30,30	/* _PAGE_USER -> PP msb */
 	rlwimi	r3,r3,32-1,31,31	/* _PAGE_USER -> PP lsb */
-	ori	r1,r1,0xe14		/* clear out reserved bits and M */
+	ori	r1,r1,0xe04		/* clear out reserved bits */
 	andc	r1,r3,r1		/* PP = user? (rw&dirty? 2: 3): 0 */
+BEGIN_FTR_SECTION
+	rlwinm	r1,r1,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
+END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
 	mtspr	SPRN_RPA,r1
 	mfspr	r3,SPRN_IMISS
 	tlbli	r3
@@ -588,8 +591,11 @@ DataLoadTLBMiss:
 	and	r1,r1,r2		/* writable if _RW and _DIRTY */
 	rlwimi	r3,r3,32-1,30,30	/* _PAGE_USER -> PP msb */
 	rlwimi	r3,r3,32-1,31,31	/* _PAGE_USER -> PP lsb */
-	ori	r1,r1,0xe14		/* clear out reserved bits and M */
+	ori	r1,r1,0xe04		/* clear out reserved bits */
 	andc	r1,r3,r1		/* PP = user? (rw&dirty? 2: 3): 0 */
+BEGIN_FTR_SECTION
+	rlwinm	r1,r1,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
+END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
 	mtspr	SPRN_RPA,r1
 	mfspr	r3,SPRN_DMISS
 	tlbld	r3
@@ -656,8 +662,11 @@ DataStoreTLBMiss:
 	stw	r3,0(r2)		/* update PTE (accessed/dirty bits) */
 	/* Convert linux-style PTE to low word of PPC-style PTE */
 	rlwimi	r3,r3,32-1,30,30	/* _PAGE_USER -> PP msb */
-	li	r1,0xe15		/* clear out reserved bits and M */
+	li	r1,0xe05		/* clear out reserved bits & PP lsb */
 	andc	r1,r3,r1		/* PP = user? 2: 0 */
+BEGIN_FTR_SECTION
+	rlwinm	r1,r1,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
+END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
 	mtspr	SPRN_RPA,r1
 	mfspr	r3,SPRN_DMISS
 	tlbld	r3
-- 
1.5.6.6