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Subject[PATCH v6 10/20] powerpc/8xx: Temporarily disable 16k pages and 512k hugepages
Date
In preparation of making use of hardware assistance in TLB handlers,
this patch temporarily disables 16K pages and 512K pages. The reason
is that when using HW assistance in 4K pages mode, the linux model
fit with the HW model for 4K pages and 8M pages.

However for 16K pages and 512K mode some additional work is needed
to get linux model fit with HW model.

Therefore the 4K pages mode will be implemented first and without
support for 512k hugepages. Then the 512k hugepages will be brought
back. And the 16K pages will be implemented in further steps.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/head_8xx.S | 36 ------------------------------------
arch/powerpc/mm/tlb_nohash.c | 3 ---
3 files changed, 1 insertion(+), 40 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3d008115fe18..287befcf37ab 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -690,7 +690,7 @@ config PPC_4K_PAGES

config PPC_16K_PAGES
bool "16k page size"
- depends on 44x || PPC_8xx
+ depends on 44x

config PPC_64K_PAGES
bool "64k page size"
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c203defe49a4..9b31721b522c 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -363,7 +363,6 @@ InstructionTLBMiss:
#ifdef CONFIG_HUGETLB_PAGE
mtcr r11
bt- 28, 10f /* bit 28 = Large page (8M) */
- bt- 29, 20f /* bit 29 = Large page (8M or 512k) */
#endif
rlwimi r10, r11, 0, 0, 32 - PAGE_SHIFT - 1 /* Add level 2 base */
lwz r10, 0(r10) /* Get the pte */
@@ -414,23 +413,8 @@ InstructionTLBMiss:

#ifdef CONFIG_HUGETLB_PAGE
10: /* 8M pages */
-#ifdef CONFIG_PPC_16K_PAGES
- /* Extract level 2 index */
- rlwinm r10, r10, 32 - (PAGE_SHIFT_8M - PAGE_SHIFT), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29
- /* Add level 2 base */
- rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1
-#else
/* Level 2 base */
rlwinm r10, r11, 0, ~HUGEPD_SHIFT_MASK
-#endif
- lwz r10, 0(r10) /* Get the pte */
- b 4b
-
-20: /* 512k pages */
- /* Extract level 2 index */
- rlwinm r10, r10, 32 - (PAGE_SHIFT_512K - PAGE_SHIFT), 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1), 29
- /* Add level 2 base */
- rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1) - 1
lwz r10, 0(r10) /* Get the pte */
b 4b
#endif
@@ -475,7 +459,6 @@ DataStoreTLBMiss:
#ifdef CONFIG_HUGETLB_PAGE
mtcr r11
bt- 28, 10f /* bit 28 = Large page (8M) */
- bt- 29, 20f /* bit 29 = Large page (8M or 512k) */
#endif
rlwimi r10, r11, 0, 0, 32 - PAGE_SHIFT - 1 /* Add level 2 base */
lwz r10, 0(r10) /* Get the pte */
@@ -537,22 +520,8 @@ DataStoreTLBMiss:
#ifdef CONFIG_HUGETLB_PAGE
10: /* 8M pages */
/* Extract level 2 index */
-#ifdef CONFIG_PPC_16K_PAGES
- rlwinm r10, r10, 32 - (PAGE_SHIFT_8M - PAGE_SHIFT), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29
- /* Add level 2 base */
- rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1
-#else
/* Level 2 base */
rlwinm r10, r11, 0, ~HUGEPD_SHIFT_MASK
-#endif
- lwz r10, 0(r10) /* Get the pte */
- b 4b
-
-20: /* 512k pages */
- /* Extract level 2 index */
- rlwinm r10, r10, 32 - (PAGE_SHIFT_512K - PAGE_SHIFT), 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1), 29
- /* Add level 2 base */
- rlwimi r10, r11, 0, 0, 32 + PAGE_SHIFT_512K - (PAGE_SHIFT << 1) - 1
lwz r10, 0(r10) /* Get the pte */
b 4b
#endif
@@ -773,12 +742,7 @@ FixupDAR:/* Entry point for dcbx workaround. */

/* concat physical page address(r11) and page offset(r10) */
200:
-#ifdef CONFIG_PPC_16K_PAGES
- rlwinm r11, r11, 0, 0, 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1) - 1
- rlwimi r11, r10, 32 - (PAGE_SHIFT_8M - 2), 32 + PAGE_SHIFT_8M - (PAGE_SHIFT << 1), 29
-#else
rlwinm r11, r10, 0, ~HUGEPD_SHIFT_MASK
-#endif
lwz r11, 0(r11) /* Get the pte */
/* concat physical page address(r11) and page offset(r10) */
rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index ae5d568e267f..8ad7aab150b7 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -97,9 +97,6 @@ struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
.shift = 14,
},
#endif
- [MMU_PAGE_512K] = {
- .shift = 19,
- },
[MMU_PAGE_8M] = {
.shift = 23,
},
--
2.13.3
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