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Subject[PATCH 05/11] powerpc/8xx: Optimise access to swapper_pg_dir
Date
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: Christophe Leroy <christophe.leroy@c-s.fr>

---
arch/powerpc/kernel/head_8xx.S | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index ae05f28..aa45225 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -322,13 +322,12 @@ InstructionTLBMiss:
mfspr r11, SPRN_M_TW /* Get level 1 table base address */
#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 */
@@ -376,12 +375,11 @@ DataStoreTLBMiss:
andis. r11, r10, 0x8000
mfspr r11, SPRN_M_TW /* Get level 1 table base address */
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.
*/
@@ -510,12 +508,11 @@ FixupDAR:/* Entry point for dcbx workaround. */
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
+ 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
@@ -670,8 +667,7 @@ 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
@@ -850,6 +846,8 @@ _GLOBAL(set_context)
stw r4, 0x4(r5)
#endif

+ 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
--
2.1.0


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