[PATCH V3 01/10] powerpc/mm/nohash: MM_SLICE is only used by book3s 64

[PATCH V3 01/10] powerpc/mm/nohash: MM_SLICE is only used by book3s 64

[Aneesh Kumar K.V]

BOOKE code is dead code as per the Kconfig details. So make it simpler
by enabling MM_SLICE only for book3s_64. The changes w.r.t nohash is just
removing deadcode. W.r.t ppc64, 4k without hugetlb will now enable MM_SLICE.
But that is good, because we reduce one extra variant which probably is not
getting tested much.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/mmu-book3e.h        | 5 -----
 arch/powerpc/include/asm/nohash/64/pgtable.h | 5 -----
 arch/powerpc/mm/hugetlbpage-book3e.c         | 7 -------
 arch/powerpc/mm/mmu_context_nohash.c         | 5 -----
 arch/powerpc/platforms/Kconfig.cputype       | 2 +-
 5 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu-book3e.h b/arch/powerpc/include/asm/mmu-book3e.h
index b62a8d43a06c..7ca8d8e80ffa 100644
--- a/arch/powerpc/include/asm/mmu-book3e.h
+++ b/arch/powerpc/include/asm/mmu-book3e.h
@@ -229,11 +229,6 @@ typedef struct {
 	unsigned int	id;
 	unsigned int	active;
 	unsigned long	vdso_base;
-#ifdef CONFIG_PPC_MM_SLICES
-	u64 low_slices_psize;   /* SLB page size encodings */
-	u64 high_slices_psize;  /* 4 bits per slice for now */
-	u16 user_psize;         /* page size index */
-#endif
 #ifdef CONFIG_PPC_64K_PAGES
 	/* for 4K PTE fragment support */
 	void *pte_frag;
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index c7f927e67d14..f0ff384d4ca5 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -88,11 +88,6 @@
 #include <asm/nohash/pte-book3e.h>
 #include <asm/pte-common.h>
 
-#ifdef CONFIG_PPC_MM_SLICES
-#define HAVE_ARCH_UNMAPPED_AREA
-#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
-#endif /* CONFIG_PPC_MM_SLICES */
-
 #ifndef __ASSEMBLY__
 /* pte_clear moved to later in this file */
 
diff --git a/arch/powerpc/mm/hugetlbpage-book3e.c b/arch/powerpc/mm/hugetlbpage-book3e.c
index 83a8be791e06..bfe4e8526b2d 100644
--- a/arch/powerpc/mm/hugetlbpage-book3e.c
+++ b/arch/powerpc/mm/hugetlbpage-book3e.c
@@ -148,16 +148,9 @@ void book3e_hugetlb_preload(struct vm_area_struct *vma, unsigned long ea,
 
 	mm = vma->vm_mm;
 
-#ifdef CONFIG_PPC_MM_SLICES
-	psize = get_slice_psize(mm, ea);
-	tsize = mmu_get_tsize(psize);
-	shift = mmu_psize_defs[psize].shift;
-#else
 	psize = vma_mmu_pagesize(vma);
 	shift = __ilog2(psize);
 	tsize = shift - 10;
-#endif
-
 	/*
 	 * We can't be interrupted while we're setting up the MAS
 	 * regusters or after we've confirmed that no tlb exists.
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index c491f2c8f2b9..4554d6527682 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -333,11 +333,6 @@ int init_new_context(struct task_struct *t, struct mm_struct *mm)
 
 	mm->context.id = MMU_NO_CONTEXT;
 	mm->context.active = 0;
-
-#ifdef CONFIG_PPC_MM_SLICES
-	slice_set_user_psize(mm, mmu_virtual_psize);
-#endif
-
 	return 0;
 }
 
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 99b0ae8acb78..a7c0c1fafe68 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -359,7 +359,7 @@ config PPC_BOOK3E_MMU
 
 config PPC_MM_SLICES
 	bool
-	default y if (!PPC_FSL_BOOK3E && PPC64 && HUGETLB_PAGE) || (PPC_STD_MMU_64 && PPC_64K_PAGES)
+	default y if PPC_STD_MMU_64
 	default n
 
 config PPC_HAVE_PMU_SUPPORT
-- 
2.7.4

[PATCH V3 02/10] powerpc/mm/slice: Fix off-by-1 error when computing slice mask

[Aneesh Kumar K.V]

For low slice, max addr should be less than 4G. Without limiting this correctly
we will end up with a low slice mask which has 17th bit set. This is not
a problem with the current code because our low slice mask is of type u16. But
in later patch I am switching low slice mask to u64 type and having the 17bit
set result in wrong slice mask which in turn results in mmap failures.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/slice.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 2b27458902ee..bf150557dba8 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -83,11 +83,10 @@ static struct slice_mask slice_range_to_mask(unsigned long start,
 	struct slice_mask ret = { 0, 0 };
 
 	if (start < SLICE_LOW_TOP) {
-		unsigned long mend = min(end, SLICE_LOW_TOP);
-		unsigned long mstart = min(start, SLICE_LOW_TOP);
+		unsigned long mend = min(end, (SLICE_LOW_TOP - 1));
 
 		ret.low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
-			- (1u << GET_LOW_SLICE_INDEX(mstart));
+			- (1u << GET_LOW_SLICE_INDEX(start));
 	}
 
 	if ((start + len) > SLICE_LOW_TOP)
-- 
2.7.4

[PATCH V3 03/10] powerpc/mm: Cleanup bits definition between hash and radix.

[Aneesh Kumar K.V]

Define everything based on bits present in pgtable.h. This will help in easily
identifying overlapping bits between hash/radix.

No functional change with this patch.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  4 ++++
 arch/powerpc/include/asm/book3s/64/hash.h     |  9 +++++----
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 10 ++--------
 arch/powerpc/include/asm/book3s/64/radix.h    |  6 ++++++
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index f3dd21efa2ea..b39f0b86405e 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -6,6 +6,10 @@
 #define H_PUD_INDEX_SIZE  5
 #define H_PGD_INDEX_SIZE  12
 
+/*
+ * 64k aligned address free up few of the lower bits of RPN for us
+ * We steal that here. For more deatils look at pte_pfn/pfn_pte()
+ */
 #define H_PAGE_COMBO	0x00001000 /* this is a combo 4k page */
 #define H_PAGE_4K_PFN	0x00002000 /* PFN is for a single 4k page */
 /*
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index f7b721bbf918..ec2828b1db07 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -13,12 +13,13 @@
  * We could create separate kernel read-only if we used the 3 PP bits
  * combinations that newer processors provide but we currently don't.
  */
-#define H_PAGE_BUSY		0x00800 /* software: PTE & hash are busy */
+#define H_PAGE_BUSY		_RPAGE_SW1 /* software: PTE & hash are busy */
 #define H_PTE_NONE_MASK		_PAGE_HPTEFLAGS
 #define H_PAGE_F_GIX_SHIFT	57
-#define H_PAGE_F_GIX		(7ul << 57)	/* HPTE index within HPTEG */
-#define H_PAGE_F_SECOND		(1ul << 60)	/* HPTE is in 2ndary HPTEG */
-#define H_PAGE_HASHPTE		(1ul << 61)	/* PTE has associated HPTE */
+/* (7ul << 57) HPTE index within HPTEG */
+#define H_PAGE_F_GIX		(_RPAGE_RSV2 | _RPAGE_RSV3 | _RPAGE_RSV4)
+#define H_PAGE_F_SECOND		_RPAGE_RSV1	/* HPTE is in 2ndary HPTEG */
+#define H_PAGE_HASHPTE		_RPAGE_SW0	/* PTE has associated HPTE */
 
 #ifdef CONFIG_PPC_64K_PAGES
 #include <asm/book3s/64/hash-64k.h>
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 8f4d41936e5a..c39bc4cb9247 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -44,14 +44,8 @@
 #endif
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
 
-/*
- * For P9 DD1 only, we need to track whether the pte's huge.
- */
-#define _PAGE_LARGE	_RPAGE_RSV1
-
-
-#define _PAGE_PTE		(1ul << 62)	/* distinguishes PTEs from pointers */
-#define _PAGE_PRESENT		(1ul << 63)	/* pte contains a translation */
+#define _PAGE_PTE		0x4000000000000000UL	/* distinguishes PTEs from pointers */
+#define _PAGE_PRESENT		0x8000000000000000UL	/* pte contains a translation */
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
  * Instead of fixing all of them, add an alternate define which
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 9e0bb7cd6e22..2a2ea47a9bd2 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -11,6 +11,12 @@
 #include <asm/book3s/64/radix-4k.h>
 #endif
 
+/*
+ * For P9 DD1 only, we need to track whether the pte's huge.
+ */
+#define _PAGE_LARGE	_RPAGE_RSV1
+
+
 #ifndef __ASSEMBLY__
 #include <asm/book3s/64/tlbflush-radix.h>
 #include <asm/cpu_has_feature.h>
-- 
2.7.4

[PATCH V3 04/10] powerpc/mm/radix: rename _PAGE_LARGE to R_PAGE_LARGE

[Aneesh Kumar K.V]

This bit is only used by radix and it is nice to follow the naming style of having
bit name start with H_/R_ depending on which translation mode they are used.

No functional change in this patch.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/hugetlb.h | 2 +-
 arch/powerpc/include/asm/book3s/64/radix.h   | 4 ++--
 arch/powerpc/mm/tlb-radix.c                  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h
index c62f14d0bec1..6666cd366596 100644
--- a/arch/powerpc/include/asm/book3s/64/hugetlb.h
+++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h
@@ -46,7 +46,7 @@ static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 	 */
 	VM_WARN_ON(page_shift == mmu_psize_defs[MMU_PAGE_1G].shift);
 	if (page_shift == mmu_psize_defs[MMU_PAGE_2M].shift)
-		return __pte(pte_val(entry) | _PAGE_LARGE);
+		return __pte(pte_val(entry) | R_PAGE_LARGE);
 	else
 		return entry;
 }
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 2a2ea47a9bd2..ac16d1943022 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -14,7 +14,7 @@
 /*
  * For P9 DD1 only, we need to track whether the pte's huge.
  */
-#define _PAGE_LARGE	_RPAGE_RSV1
+#define R_PAGE_LARGE	_RPAGE_RSV1
 
 
 #ifndef __ASSEMBLY__
@@ -258,7 +258,7 @@ static inline int radix__pmd_trans_huge(pmd_t pmd)
 static inline pmd_t radix__pmd_mkhuge(pmd_t pmd)
 {
 	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
-		return __pmd(pmd_val(pmd) | _PAGE_PTE | _PAGE_LARGE);
+		return __pmd(pmd_val(pmd) | _PAGE_PTE | R_PAGE_LARGE);
 	return __pmd(pmd_val(pmd) | _PAGE_PTE);
 }
 static inline void radix__pmdp_huge_split_prepare(struct vm_area_struct *vma,
diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index 952713d6cf04..83dc1ccc2fa1 100644
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -437,7 +437,7 @@ void radix__flush_tlb_pte_p9_dd1(unsigned long old_pte, struct mm_struct *mm,
 		return;
 	}
 
-	if (old_pte & _PAGE_LARGE)
+	if (old_pte & R_PAGE_LARGE)
 		radix__flush_tlb_page_psize(mm, address, MMU_PAGE_2M);
 	else
 		radix__flush_tlb_page_psize(mm, address, mmu_virtual_psize);
-- 
2.7.4

[PATCH V3 05/10] powerpc/mm: Add translation mode information in /proc/cpuinfo

[Aneesh Kumar K.V]

With this we have on powernv and pseries /proc/cpuinfo reporting

timebase        : 512000000
platform        : PowerNV
model           : 8247-22L
machine         : PowerNV 8247-22L
firmware        : OPAL
MMU		: Hash

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/setup.c | 4 ++++
 arch/powerpc/platforms/pseries/setup.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index d50c7d99baaf..2d937f6d9260 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -95,6 +95,10 @@ static void pnv_show_cpuinfo(struct seq_file *m)
 	else
 		seq_printf(m, "firmware\t: BML\n");
 	of_node_put(root);
+	if (radix_enabled())
+		seq_printf(m, "MMU\t\t: Radix\n");
+	else
+		seq_printf(m, "MMU\t\t: Hash\n");
 }
 
 static void pnv_prepare_going_down(void)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index b4d362ed03a1..b5d86426e97b 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -87,6 +87,10 @@ static void pSeries_show_cpuinfo(struct seq_file *m)
 		model = of_get_property(root, "model", NULL);
 	seq_printf(m, "machine\t\t: CHRP %s\n", model);
 	of_node_put(root);
+	if (radix_enabled())
+		seq_printf(m, "MMU\t\t: Radix\n");
+	else
+		seq_printf(m, "MMU\t\t: Hash\n");
 }
 
 /* Initialize firmware assisted non-maskable interrupts if
-- 
2.7.4

[PATCH V3 06/10] powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout

[Aneesh Kumar K.V]

Without this if firmware reports 1MB page size support we will crash
trying to use 1MB as hugetlb page size.

echo 300 > /sys/kernel/mm/hugepages/hugepages-1024kB/nr_hugepages

kernel BUG at ./arch/powerpc/include/asm/hugetlb.h:19!
.....
....
[c0000000e2c27b30] c00000000029dae8 .hugetlb_fault+0x638/0xda0
[c0000000e2c27c30] c00000000026fb64 .handle_mm_fault+0x844/0x1d70
[c0000000e2c27d70] c00000000004805c .do_page_fault+0x3dc/0x7c0
[c0000000e2c27e30] c00000000000ac98 handle_page_fault+0x10/0x30

With fix, we don't enable 1MB as hugepage size.

bash-4.2# cd /sys/kernel/mm/hugepages/
bash-4.2# ls
hugepages-16384kB  hugepages-16777216kB

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hugetlbpage.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 8c3389cbcd12..a4f33de4008e 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -753,6 +753,24 @@ static int __init add_huge_page_size(unsigned long long size)
 	if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
 		return -EINVAL;
 
+#ifdef CONFIG_PPC_BOOK3S_64
+	/*
+	 * We need to make sure that for different page sizes reported by
+	 * firmware we only add hugetlb support for page sizes that can be
+	 * supported by linux page table layout.
+	 * For now we have
+	 * Radix: 2M
+	 * Hash: 16M and 16G
+	 */
+	if (radix_enabled()) {
+		if (mmu_psize != MMU_PAGE_2M)
+			return -EINVAL;
+	} else {
+		if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G)
+			return -EINVAL;
+	}
+#endif
+
 	BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
 
 	/* Return if huge page size has already been setup */
-- 
2.7.4

[PATCH V3 07/10] powerpc/mm: Define _PAGE_SOFT_DIRTY unconditionally

[Aneesh Kumar K.V]

Conditional PTE bit definition is confusing and results in coding error.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index c39bc4cb9247..4d4ff9a324f0 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -37,11 +37,7 @@
 #define _RPAGE_RSV3		0x0400000000000000UL
 #define _RPAGE_RSV4		0x0200000000000000UL
 
-#ifdef CONFIG_MEM_SOFT_DIRTY
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
-#else
-#define _PAGE_SOFT_DIRTY	0x00000
-#endif
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
 
 #define _PAGE_PTE		0x4000000000000000UL	/* distinguishes PTEs from pointers */
-- 
2.7.4

[PATCH V3 08/10] powerpc/mm: Define all PTE bits based on radix definitions.

[Aneesh Kumar K.V]

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/hash-64k.h | 4 ++--
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index b39f0b86405e..7be54f9590a3 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -10,8 +10,8 @@
  * 64k aligned address free up few of the lower bits of RPN for us
  * We steal that here. For more deatils look at pte_pfn/pfn_pte()
  */
-#define H_PAGE_COMBO	0x00001000 /* this is a combo 4k page */
-#define H_PAGE_4K_PFN	0x00002000 /* PFN is for a single 4k page */
+#define H_PAGE_COMBO	_RPAGE_RPN0 /* this is a combo 4k page */
+#define H_PAGE_4K_PFN	_RPAGE_RPN1 /* PFN is for a single 4k page */
 /*
  * We need to differentiate between explicit huge page and THP huge
  * page, since THP huge page also need to track real subpage details
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 4d4ff9a324f0..96566df547a8 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -36,6 +36,8 @@
 #define _RPAGE_RSV2		0x0800000000000000UL
 #define _RPAGE_RSV3		0x0400000000000000UL
 #define _RPAGE_RSV4		0x0200000000000000UL
+#define _RPAGE_RPN0		0x01000
+#define _RPAGE_RPN1		0x02000
 
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
-- 
2.7.4

[PATCH V3 09/10] powerpc/mm: Lower the max real address to 53 bits

[Aneesh Kumar K.V]

Max value supported by hardware is 51 bits address. Radix page table define
a slot of 57 bits for future expansion. We restrict the value supported in
linux kernel 53 bits, so that we can use the bits between 57-53 for storing
hash linux page table bits. This is done in the next patch.

This will free up the software page table bits to be used for features
that are needed for both hash and radix. The current hash linux page table
format doesn't have any free software bits. Moving hash linux page table
specific bits to top of RPN field free up the software bits for other purpose.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 29 +++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 96566df547a8..881fa7060b13 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -38,6 +38,28 @@
 #define _RPAGE_RSV4		0x0200000000000000UL
 #define _RPAGE_RPN0		0x01000
 #define _RPAGE_RPN1		0x02000
+/* Max physical address bit as per radix table */
+#define _RPAGE_PA_MAX		57
+/*
+ * Max physical address bit we will use for now.
+ *
+ * This is mostly a hardware limitation and for now Power9 has
+ * a 51 bit limit.
+ *
+ * This is different from the number of physical bit required to address
+ * the last byte of memory. That is defined by MAX_PHYSMEM_BITS.
+ * MAX_PHYSMEM_BITS is a linux limitation imposed by the maximum
+ * number of sections we can support (SECTIONS_SHIFT).
+ *
+ * This is different from Radix page table limitation above and
+ * should always be less than that. The limit is done such that
+ * we can overload the bits between _RPAGE_PA_MAX and _PAGE_PA_MAX
+ * for hash linux page table specific bits.
+ *
+ * In order to be compatible with future hardware generations we keep
+ * some offsets and limit this for now to 53
+ */
+#define _PAGE_PA_MAX		53
 
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
@@ -51,10 +73,11 @@
  */
 #define _PAGE_NO_CACHE		_PAGE_TOLERANT
 /*
- * We support 57 bit real address in pte. Clear everything above 57, and
- * every thing below PAGE_SHIFT;
+ * We support _RPAGE_PA_MAX bit real address in pte. On the linux side
+ * we are limited by _PAGE_PA_MAX. Clear everything above _PAGE_PA_MAX
+ * and every thing below PAGE_SHIFT;
  */
-#define PTE_RPN_MASK	(((1UL << 57) - 1) & (PAGE_MASK))
+#define PTE_RPN_MASK	(((1UL << _PAGE_PA_MAX) - 1) & (PAGE_MASK))
 /*
  * set of bits not changed in pmd_modify. Even though we have hash specific bits
  * in here, on radix we expect them to be zero.
-- 
2.7.4

[PATCH V3 10/10] powerpc/mm: Move hash specific pte bits to be top bits of RPN

[Aneesh Kumar K.V]

We don't support the full 57 bits of physical address and hence can overload
the top bits of RPN as hash specific pte bits.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/hash.h    | 17 +++++------------
 arch/powerpc/include/asm/book3s/64/pgtable.h | 17 ++++++++++++++---
 arch/powerpc/mm/hash_native_64.c             |  1 +
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index ec2828b1db07..4e957b027fe0 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -6,20 +6,13 @@
  * Common bits between 4K and 64K pages in a linux-style PTE.
  * Additional bits may be defined in pgtable-hash64-*.h
  *
- * Note: We only support user read/write permissions. Supervisor always
- * have full read/write to pages above PAGE_OFFSET (pages below that
- * always use the user access permissions).
- *
- * We could create separate kernel read-only if we used the 3 PP bits
- * combinations that newer processors provide but we currently don't.
  */
-#define H_PAGE_BUSY		_RPAGE_SW1 /* software: PTE & hash are busy */
 #define H_PTE_NONE_MASK		_PAGE_HPTEFLAGS
-#define H_PAGE_F_GIX_SHIFT	57
-/* (7ul << 57) HPTE index within HPTEG */
-#define H_PAGE_F_GIX		(_RPAGE_RSV2 | _RPAGE_RSV3 | _RPAGE_RSV4)
-#define H_PAGE_F_SECOND		_RPAGE_RSV1	/* HPTE is in 2ndary HPTEG */
-#define H_PAGE_HASHPTE		_RPAGE_SW0	/* PTE has associated HPTE */
+#define H_PAGE_F_GIX_SHIFT	56
+#define H_PAGE_BUSY		_RPAGE_RSV1 /* software: PTE & hash are busy */
+#define H_PAGE_F_SECOND		_RPAGE_RSV2	/* HPTE is in 2ndary HPTEG */
+#define H_PAGE_F_GIX		(_RPAGE_RSV3 | _RPAGE_RSV4 | _RPAGE_RPN44)
+#define H_PAGE_HASHPTE		_RPAGE_RPN43	/* PTE has associated HPTE */
 
 #ifdef CONFIG_PPC_64K_PAGES
 #include <asm/book3s/64/hash-64k.h>
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 881fa7060b13..20c51b84c656 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -36,8 +36,22 @@
 #define _RPAGE_RSV2		0x0800000000000000UL
 #define _RPAGE_RSV3		0x0400000000000000UL
 #define _RPAGE_RSV4		0x0200000000000000UL
+
+#define _PAGE_PTE		0x4000000000000000UL	/* distinguishes PTEs from pointers */
+#define _PAGE_PRESENT		0x8000000000000000UL	/* pte contains a translation */
+
+/*
+ * Top and bottom bits of RPN which can be used by hash
+ * translation mode, because we expect them to be zero
+ * otherwise.
+ */
 #define _RPAGE_RPN0		0x01000
 #define _RPAGE_RPN1		0x02000
+#define _RPAGE_RPN44		0x0100000000000000UL
+#define _RPAGE_RPN43		0x0080000000000000UL
+#define _RPAGE_RPN42		0x0040000000000000UL
+#define _RPAGE_RPN41		0x0020000000000000UL
+
 /* Max physical address bit as per radix table */
 #define _RPAGE_PA_MAX		57
 /*
@@ -63,9 +77,6 @@
 
 #define _PAGE_SOFT_DIRTY	_RPAGE_SW3 /* software: software dirty tracking */
 #define _PAGE_SPECIAL		_RPAGE_SW2 /* software: special page */
-
-#define _PAGE_PTE		0x4000000000000000UL	/* distinguishes PTEs from pointers */
-#define _PAGE_PRESENT		0x8000000000000000UL	/* pte contains a translation */
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
  * Instead of fixing all of them, add an alternate define which
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index cc332608e656..917a5a336441 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -246,6 +246,7 @@ static long native_hpte_insert(unsigned long hpte_group, unsigned long vpn,
 
 	__asm__ __volatile__ ("ptesync" : : : "memory");
 
+	BUILD_BUG_ON(H_PAGE_F_SECOND != (1ul  << (H_PAGE_F_GIX_SHIFT + 3)));
 	return i | (!!(vflags & HPTE_V_SECONDARY) << 3);
 }
 
-- 
2.7.4

Re: [PATCH V3 09/10] powerpc/mm: Lower the max real address to 53 bits

[Paul Mackerras]

On Tue, Mar 21, 2017 at 10:59:59PM +0530, Aneesh Kumar K.V wrote:
> Max value supported by hardware is 51 bits address. Radix page table define
> a slot of 57 bits for future expansion. We restrict the value supported in
> linux kernel 53 bits, so that we can use the bits between 57-53 for storing
> hash linux page table bits. This is done in the next patch.
> 
> This will free up the software page table bits to be used for features
> that are needed for both hash and radix. The current hash linux page table
> format doesn't have any free software bits. Moving hash linux page table
> specific bits to top of RPN field free up the software bits for other purpose.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>

Re: [PATCH V3 10/10] powerpc/mm: Move hash specific pte bits to be top bits of RPN

[Paul Mackerras]

On Tue, Mar 21, 2017 at 11:00:00PM +0530, Aneesh Kumar K.V wrote:
> We don't support the full 57 bits of physical address and hence can overload
> the top bits of RPN as hash specific pte bits.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>

Re: [V3,01/10] powerpc/mm/nohash: MM_SLICE is only used by book3s 64

[Michael Ellerman]

On Tue, 2017-03-21 at 17:29:51 UTC, "Aneesh Kumar K.V" wrote:
> BOOKE code is dead code as per the Kconfig details. So make it simpler
> by enabling MM_SLICE only for book3s_64. The changes w.r.t nohash is just
> removing deadcode. W.r.t ppc64, 4k without hugetlb will now enable MM_SLICE.
> But that is good, because we reduce one extra variant which probably is not
> getting tested much.
> 
> Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/b42279f0165cdfb093718ec368e56d

cheers