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Commit fde5a905 authored by LEROY Christophe's avatar LEROY Christophe Committed by Scott Wood
Browse files

powerpc/8xx: Optimise access to swapper_pg_dir 



All accessed to PGD entries are done via 0(r11).
By using lower part of swapper_pg_dir as load index to r11, we can remove the
ori instruction.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarScott Wood <scottwood@freescale.com>
parent 17bb312f

arch/powerpc/kernel/head_8xx.S

+19 −16
Original line number Diff line number Diff line
@@ -319,16 +319,15 @@ InstructionTLBMiss: 
	 * pin the first 8MB of kernel memory */

	andis.	r11, r10, 0x8000	/* Address >= 0x80000000 */

#endif

	mfspr	r11, SPRN_M_TW	/* Get level 1 table base address */

	mfspr	r11, SPRN_M_TW	/* Get level 1 table */

#ifdef CONFIG_MODULES

	beq	3f

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@h

	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@ha

3:

#endif

	/* 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 */

	lwz	r11, (swapper_pg_dir-PAGE_OFFSET)@l(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 */
@@ -374,14 +373,13 @@ DataStoreTLBMiss: 
	 * kernel page tables.

	 */

	andis.	r11, r10, 0x8000

	mfspr	r11, SPRN_M_TW	/* Get level 1 table base address */

	mfspr	r11, SPRN_M_TW	/* Get level 1 table */

	beq	3f

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@h

	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@ha

3:

	/* 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 */

	lwz	r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11)	/* Get the level 1 entry */



	/* We have a pte table, so load fetch the pte from the table.

	 */
@@ -506,13 +504,12 @@ FixupDAR:/* Entry point for dcbx workaround. */ 
	/* fetch instruction from memory. */

	mfspr	r10, SPRN_SRR0

	andis.	r11, r10, 0x8000	/* Address >= 0x80000000 */

	mfspr	r11, SPRN_M_TW	/* Get level 1 table base address */

	beq-	3f		/* Branch if user space */

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@h

	ori	r11, r11, (swapper_pg_dir-PAGE_OFFSET)@l

	mfspr	r11, SPRN_M_TW	/* Get level 1 table */

	beq	3f

	lis	r11, (swapper_pg_dir-PAGE_OFFSET)@ha

	/* 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 */

	lwz	r11, (swapper_pg_dir-PAGE_OFFSET)@l(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
@@ -667,8 +664,7 @@ start_here: 
	 * init's THREAD like the context switch code does, but this is

	 * easier......until someone changes init's static structures.

	 */

	lis	r6, swapper_pg_dir@h

	ori	r6, r6, swapper_pg_dir@l

	lis	r6, swapper_pg_dir@ha

	tophys(r6,r6)

#ifdef CONFIG_8xx_CPU6

	lis	r4, cpu6_errata_word@h
@@ -847,6 +843,13 @@ _GLOBAL(set_context) 
	stw	r4, 0x4(r5)

#endif



	/* Register M_TW will contain base address of level 1 table minus the

	 * lower part of the kernel PGDIR base address, so that all accesses to

	 * level 1 table are done relative to lower part of kernel PGDIR base

	 * address.

	 */

	li	r5, (swapper_pg_dir-PAGE_OFFSET)@l

	sub	r4, r4, r5

#ifdef CONFIG_8xx_CPU6

	lis	r6, cpu6_errata_word@h

	ori	r6, r6, cpu6_errata_word@l
@@ -854,7 +857,7 @@ _GLOBAL(set_context) 
	li	r7, 0x3f80

	stw	r7, 12(r6)

	lwz	r7, 12(r6)

        mtspr   SPRN_M_TW, r4               /* Update MMU base address */

	mtspr	SPRN_M_TW, r4		/* Update pointeur to level 1 table */

	li	r7, 0x3380

	stw	r7, 12(r6)

	lwz	r7, 12(r6)