powerpc/8xx: Temporarily disable 16k pages and hugepages

In preparation of making use of hardware assistance in TLB handlers,
this patch temporarily disables 16K pages and hugepages. 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.
For the 8M pages, they will naturaly come back when we switch to
HW assistance, without any additional handling.
In order to keep the following patch smaller, the removal of the
current special handling for 8M pages gets removed here as well.

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 the following step.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8ea7c2c..bfb5ee9 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -689,7 +689,7 @@ 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 c203def..01f58b1 100644 (file)
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -314,7 +314,7 @@ SystemCall:
 InstructionTLBMiss:
        mtspr   SPRN_SPRG_SCRATCH0, r10
        mtspr   SPRN_SPRG_SCRATCH1, r11
-#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
+#ifdef ITLB_MISS_KERNEL
        mtspr   SPRN_SPRG_SCRATCH2, r12
 #endif
 
@@ -325,10 +325,8 @@ InstructionTLBMiss:
        INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10)
        /* Only modules will cause ITLB Misses as we always
         * pin the first 8MB of kernel memory */
-#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
-       mfcr    r12
-#endif
 #ifdef ITLB_MISS_KERNEL
+       mfcr    r12
 #if defined(SIMPLE_KERNEL_ADDRESS) && defined(CONFIG_PIN_TLB_TEXT)
        andis.  r11, r10, 0x8000        /* Address >= 0x80000000 */
 #else
@@ -360,15 +358,9 @@ InstructionTLBMiss:
 
        /* Extract level 2 index */
        rlwinm  r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
-#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 */
-4:
-#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
+#ifdef ITLB_MISS_KERNEL
        mtcr    r12
 #endif
        /* Load the MI_TWC with the attributes for this "segment." */
@@ -393,7 +385,7 @@ InstructionTLBMiss:
        /* Restore registers */
 0:     mfspr   r10, SPRN_SPRG_SCRATCH0
        mfspr   r11, SPRN_SPRG_SCRATCH1
-#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
+#ifdef ITLB_MISS_KERNEL
        mfspr   r12, SPRN_SPRG_SCRATCH2
 #endif
        rfi
@@ -406,35 +398,12 @@ InstructionTLBMiss:
        stw     r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)
        mfspr   r10, SPRN_SPRG_SCRATCH0
        mfspr   r11, SPRN_SPRG_SCRATCH1
-#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
+#ifdef ITLB_MISS_KERNEL
        mfspr   r12, SPRN_SPRG_SCRATCH2
 #endif
        rfi
 #endif
 
-#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
-
        . = 0x1200
 DataStoreTLBMiss:
        mtspr   SPRN_SPRG_SCRATCH0, r10
@@ -472,11 +441,6 @@ DataStoreTLBMiss:
         */
        /* Extract level 2 index */
        rlwinm  r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
-#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 */
 4:
@@ -534,29 +498,6 @@ DataStoreTLBMiss:
        rfi
 #endif
 
-#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
-
 /* This is an instruction TLB error on the MPC8xx.  This could be due
  * to many reasons, such as executing guarded memory or illegal instruction
  * addresses.  There is nothing to do but handle a big time error fault.
@@ -773,12 +714,7 @@ 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 ae5d568..4f79639 100644 (file)
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -97,12 +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,
-       },
 };
 #else
 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {