linux-kernel - [PATCH 04/11] powerpc/8xx: Take benefit of aligned PGDIR

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Message-Id: <20150420052630.DA6751A242C@localhost.localdomain>
Date:	Mon, 20 Apr 2015 07:26:30 +0200 (CEST)
From:	Christophe Leroy <christophe.leroy@....fr>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>, scottwood@...escale.com
CC:	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	Joakim Tjernlund <joakim.tjernlund@...nsmode.se>
Subject: [PATCH 04/11] powerpc/8xx: Take benefit of aligned PGDIR

L1 base address is now aligned so we can insert L1 index into r11 directly and
then preserve r10

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>

---
 arch/powerpc/kernel/head_8xx.S | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 2c329f1..ae05f28 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -326,16 +326,15 @@ InstructionTLBMiss:
 	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l
 3:
 #endif
-	/* Extract level 1 index */
-	rlwinm	r10, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
-	lwzx	r11, r10, r11	/* Get the level 1 entry */
-	rlwinm	r10, r11,0,0,19	/* Extract page descriptor page address */
+	/* Insert level 1 index */
+	rlwimi	r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
+	lwz	r11, 0(r11)	/* Get the level 1 entry */
 
 	/* Load the MI_TWC with the attributes for this "segment." */
 	MTSPR_CPU6(SPRN_MI_TWC, r11, r3)	/* Set segment attributes */
-	mfspr	r11, SPRN_SRR0	/* Get effective address of fault */
+	rlwinm	r11, r11,0,0,19	/* Extract page descriptor page address */
 	/* Extract level 2 index */
-	rlwinm	r11, r11, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
+	rlwinm	r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
 	lwzx	r10, r10, r11	/* Get the pte */
 
 #ifdef CONFIG_SWAP
@@ -380,13 +379,12 @@ DataStoreTLBMiss:
 	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@h
 	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l
 3:
-	/* Extract level 1 index */
-	rlwinm	r10, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
-	lwzx	r11, r10, r11	/* Get the level 1 entry */
+	/* Insert level 1 index */
+	rlwimi	r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
+	lwz	r11, 0(r11)	/* Get the level 1 entry */
 
 	/* We have a pte table, so load fetch the pte from the table.
 	 */
-	mfspr	r10, SPRN_MD_EPN	/* Get address of fault */
 	/* Extract level 2 index */
 	rlwinm	r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
 	rlwimi	r10, r11, 0, 0, 32 - PAGE_SHIFT - 1	/* Add level 2 base */
@@ -515,16 +513,14 @@ FixupDAR:/* Entry point for dcbx workaround. */
 	beq-	3f		/* Branch if user space */
 	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@h
 	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l
-	/* Extract level 1 index */
-3:	rlwinm	r10, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
-	lwzx	r11, r10, r11	/* Get the level 1 entry */
-	rlwinm	r10, r11,0,0,19	/* Extract page descriptor page address */
-	mfspr	r11, SPRN_SRR0	/* Get effective address of fault */
-	/* Extract level 2 index */
-	rlwinm	r11, r11, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
-	lwzx	r11, r10, r11	/* Get the pte */
+	/* Insert level 1 index */
+3:	rlwimi	r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
+	lwz	r11, 0(r11)	/* Get the level 1 entry */
+	rlwinm	r11, r11,0,0,19	/* Extract page descriptor page address */
+	/* Insert level 2 index */
+	rlwimi	r11, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
+	lwz	r11, 0(r11)	/* Get the pte */
 	/* concat physical page address(r11) and page offset(r10) */
-	mfspr	r10, SPRN_SRR0
 	rlwimi	r11, r10, 0, 32 - PAGE_SHIFT, 31
 	lwz	r11,0(r11)
 /* Check if it really is a dcbx instruction. */
-- 
2.1.0

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