[PATCH V3 00/10] powerpc/mm/ppc64: Add 128TB support

[PATCH V3 00/10] powerpc/mm/ppc64: Add 128TB support

[Aneesh Kumar K.V]

This patch series increase the effective virtual address range of
applications from 64TB to 128TB. We do that by supporting a 
68 bit virtual address. On platforms that can only do 65 bit virtual
address we limit the max contexts to a 16bit value instead of 19.

The patch series also switch the page table layout such that we can
do 512TB effective address. But we still limit the TASK_SIZE to
128TB. This was done to make sure we don't break applications
that make assumption regarding the max address returned by the
OS. We can switch to 128TB without a linux personality value because
other architectures do 128TB as max address.

Changes from V2:
* Handle hugepage size correctly.

Aneesh Kumar K.V (10):
  powerpc/mm/slice: Convert slice_mask high slice to a bitmap
  powerpc/mm/slice: Update the function prototype
  powerpc/mm/hash: Move kernel context to the starting of context range
  powerpc/mm/hash: Support 68 bit VA
  powerpc/mm: Move copy_mm_to_paca to paca.c
  powerpc/mm: Remove redundant TASK_SIZE_USER64 checks
  powerpc/mm/slice: Use mm task_size as max value of slice index
  powerpc/mm/hash: Increase VA range to 128TB
  powerpc/mm/slice: Move slice_mask struct definition to slice.c
  powerpc/mm/slice: Update slice mask printing to use bitmap printing.

 arch/powerpc/include/asm/book3s/64/hash-4k.h  |   2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |   2 +-
 arch/powerpc/include/asm/book3s/64/mmu-hash.h | 160 ++++++++++++---------
 arch/powerpc/include/asm/mmu.h                |  19 ++-
 arch/powerpc/include/asm/mmu_context.h        |   2 +-
 arch/powerpc/include/asm/paca.h               |  18 +--
 arch/powerpc/include/asm/page_64.h            |  14 --
 arch/powerpc/include/asm/processor.h          |  22 ++-
 arch/powerpc/kernel/paca.c                    |  26 ++++
 arch/powerpc/kvm/book3s_64_mmu_host.c         |  10 +-
 arch/powerpc/mm/hash_utils_64.c               |   9 +-
 arch/powerpc/mm/init_64.c                     |   4 -
 arch/powerpc/mm/mmu_context_book3s64.c        |  96 +++++++++----
 arch/powerpc/mm/pgtable_64.c                  |   5 -
 arch/powerpc/mm/slb.c                         |   2 +-
 arch/powerpc/mm/slb_low.S                     |  74 ++++++----
 arch/powerpc/mm/slice.c                       | 195 +++++++++++++++-----------
 17 files changed, 394 insertions(+), 266 deletions(-)

-- 
2.7.4

[PATCH V3 01/10] powerpc/mm/slice: Convert slice_mask high slice to a bitmap

[Aneesh Kumar K.V]

In followup patch we want to increase the va range which will result
in us requiring high_slices to have more than 64 bits. To enable this
convert high_slices to bitmap. We keep the number bits same in this patch
and later change that to higher value

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/page_64.h |  15 ++---
 arch/powerpc/mm/slice.c            | 110 +++++++++++++++++++++++++------------
 2 files changed, 80 insertions(+), 45 deletions(-)

diff --git a/arch/powerpc/include/asm/page_64.h b/arch/powerpc/include/asm/page_64.h
index dd5f0712afa2..7f72659b7999 100644
--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h
@@ -98,19 +98,16 @@ extern u64 ppc64_pft_size;
 #define GET_LOW_SLICE_INDEX(addr)	((addr) >> SLICE_LOW_SHIFT)
 #define GET_HIGH_SLICE_INDEX(addr)	((addr) >> SLICE_HIGH_SHIFT)
 
+#ifndef __ASSEMBLY__
 /*
- * 1 bit per slice and we have one slice per 1TB
- * Right now we support only 64TB.
- * IF we change this we will have to change the type
- * of high_slices
+ * One bit per slice. We have lower slices which cover 256MB segments
+ * upto 4G range. That gets us 16 low slices. For the rest we track slices
+ * in 1TB size.
+ * 64 below is actually SLICE_NUM_HIGH to fixup complie errros
  */
-#define SLICE_MASK_SIZE 8
-
-#ifndef __ASSEMBLY__
-
 struct slice_mask {
 	u16 low_slices;
-	u64 high_slices;
+	DECLARE_BITMAP(high_slices, 64);
 };
 
 struct mm_struct;
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 2b27458902ee..c4e718e38a03 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -36,11 +36,6 @@
 #include <asm/copro.h>
 #include <asm/hugetlb.h>
 
-/* some sanity checks */
-#if (H_PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
-#error H_PGTABLE_RANGE exceeds slice_mask high_slices size
-#endif
-
 static DEFINE_SPINLOCK(slice_convert_lock);
 
 
@@ -49,7 +44,7 @@ int _slice_debug = 1;
 
 static void slice_print_mask(const char *label, struct slice_mask mask)
 {
-	char	*p, buf[16 + 3 + 64 + 1];
+	char	*p, buf[SLICE_NUM_LOW + 3 + SLICE_NUM_HIGH + 1];
 	int	i;
 
 	if (!_slice_debug)
@@ -60,8 +55,12 @@ static void slice_print_mask(const char *label, struct slice_mask mask)
 	*(p++) = ' ';
 	*(p++) = '-';
 	*(p++) = ' ';
-	for (i = 0; i < SLICE_NUM_HIGH; i++)
-		*(p++) = (mask.high_slices & (1ul << i)) ? '1' : '0';
+	for (i = 0; i < SLICE_NUM_HIGH; i++) {
+		if (test_bit(i, mask.high_slices))
+			*(p++) = '1';
+		else
+			*(p++) = '0';
+	}
 	*(p++) = 0;
 
 	printk(KERN_DEBUG "%s:%s\n", label, buf);
@@ -80,7 +79,10 @@ static struct slice_mask slice_range_to_mask(unsigned long start,
 					     unsigned long len)
 {
 	unsigned long end = start + len - 1;
-	struct slice_mask ret = { 0, 0 };
+	struct slice_mask ret;
+
+	ret.low_slices = 0;
+	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
 
 	if (start < SLICE_LOW_TOP) {
 		unsigned long mend = min(end, SLICE_LOW_TOP);
@@ -90,10 +92,13 @@ static struct slice_mask slice_range_to_mask(unsigned long start,
 			- (1u << GET_LOW_SLICE_INDEX(mstart));
 	}
 
-	if ((start + len) > SLICE_LOW_TOP)
-		ret.high_slices = (1ul << (GET_HIGH_SLICE_INDEX(end) + 1))
-			- (1ul << GET_HIGH_SLICE_INDEX(start));
+	if ((start + len) > SLICE_LOW_TOP) {
+		unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
+		unsigned long align_end = ALIGN(end, (1UL <<SLICE_HIGH_SHIFT));
+		unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
 
+		bitmap_set(ret.high_slices, start_index, count);
+	}
 	return ret;
 }
 
@@ -130,9 +135,12 @@ static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
 
 static struct slice_mask slice_mask_for_free(struct mm_struct *mm)
 {
-	struct slice_mask ret = { 0, 0 };
+	struct slice_mask ret;
 	unsigned long i;
 
+	ret.low_slices = 0;
+	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
+
 	for (i = 0; i < SLICE_NUM_LOW; i++)
 		if (!slice_low_has_vma(mm, i))
 			ret.low_slices |= 1u << i;
@@ -142,7 +150,7 @@ static struct slice_mask slice_mask_for_free(struct mm_struct *mm)
 
 	for (i = 0; i < SLICE_NUM_HIGH; i++)
 		if (!slice_high_has_vma(mm, i))
-			ret.high_slices |= 1ul << i;
+			__set_bit(i, ret.high_slices);
 
 	return ret;
 }
@@ -151,10 +159,13 @@ static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
 {
 	unsigned char *hpsizes;
 	int index, mask_index;
-	struct slice_mask ret = { 0, 0 };
+	struct slice_mask ret;
 	unsigned long i;
 	u64 lpsizes;
 
+	ret.low_slices = 0;
+	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
+
 	lpsizes = mm->context.low_slices_psize;
 	for (i = 0; i < SLICE_NUM_LOW; i++)
 		if (((lpsizes >> (i * 4)) & 0xf) == psize)
@@ -165,7 +176,7 @@ static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
 		mask_index = i & 0x1;
 		index = i >> 1;
 		if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
-			ret.high_slices |= 1ul << i;
+			__set_bit(i, ret.high_slices);
 	}
 
 	return ret;
@@ -173,8 +184,13 @@ static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
 
 static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
 {
+	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
+
+	bitmap_and(result, mask.high_slices,
+		   available.high_slices, SLICE_NUM_HIGH);
+
 	return (mask.low_slices & available.low_slices) == mask.low_slices &&
-		(mask.high_slices & available.high_slices) == mask.high_slices;
+		bitmap_equal(result, mask.high_slices, SLICE_NUM_HIGH);
 }
 
 static void slice_flush_segments(void *parm)
@@ -221,7 +237,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
 	for (i = 0; i < SLICE_NUM_HIGH; i++) {
 		mask_index = i & 0x1;
 		index = i >> 1;
-		if (mask.high_slices & (1ul << i))
+		if (test_bit(i, mask.high_slices))
 			hpsizes[index] = (hpsizes[index] &
 					  ~(0xf << (mask_index * 4))) |
 				(((unsigned long)psize) << (mask_index * 4));
@@ -257,7 +273,7 @@ static bool slice_scan_available(unsigned long addr,
 		slice = GET_HIGH_SLICE_INDEX(addr);
 		*boundary_addr = (slice + end) ?
 			((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
-		return !!(available.high_slices & (1ul << slice));
+		return !!test_bit(slice, available.high_slices);
 	}
 }
 
@@ -364,15 +380,24 @@ static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
 		return slice_find_area_bottomup(mm, len, mask, psize);
 }
 
-#define or_mask(dst, src)	do {			\
-	(dst).low_slices |= (src).low_slices;		\
-	(dst).high_slices |= (src).high_slices;		\
-} while (0)
+static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src)
+{
+	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
 
-#define andnot_mask(dst, src)	do {			\
-	(dst).low_slices &= ~(src).low_slices;		\
-	(dst).high_slices &= ~(src).high_slices;	\
-} while (0)
+	dst->low_slices |= src->low_slices;
+	bitmap_or(result, dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
+	bitmap_copy(dst->high_slices, result, SLICE_NUM_HIGH);
+}
+
+static inline void slice_andnot_mask(struct slice_mask *dst, struct slice_mask *src)
+{
+	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
+
+	dst->low_slices &= ~src->low_slices;
+
+	bitmap_andnot(result, dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
+	bitmap_copy(dst->high_slices, result, SLICE_NUM_HIGH);
+}
 
 #ifdef CONFIG_PPC_64K_PAGES
 #define MMU_PAGE_BASE	MMU_PAGE_64K
@@ -384,15 +409,28 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 				      unsigned long flags, unsigned int psize,
 				      int topdown)
 {
-	struct slice_mask mask = {0, 0};
+	struct slice_mask mask;
 	struct slice_mask good_mask;
-	struct slice_mask potential_mask = {0,0} /* silence stupid warning */;
-	struct slice_mask compat_mask = {0, 0};
+	struct slice_mask potential_mask;
+	struct slice_mask compat_mask;
 	int fixed = (flags & MAP_FIXED);
 	int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
 	struct mm_struct *mm = current->mm;
 	unsigned long newaddr;
 
+	/*
+	 * init different masks
+	 */
+	mask.low_slices = 0;
+	bitmap_zero(mask.high_slices, SLICE_NUM_HIGH);
+
+	/* silence stupid warning */;
+	potential_mask.low_slices = 0;
+	bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
+
+	compat_mask.low_slices = 0;
+	bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH);
+
 	/* Sanity checks */
 	BUG_ON(mm->task_size == 0);
 	VM_BUG_ON(radix_enabled());
@@ -450,7 +488,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	if (psize == MMU_PAGE_64K) {
 		compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
 		if (fixed)
-			or_mask(good_mask, compat_mask);
+			slice_or_mask(&good_mask, &compat_mask);
 	}
 #endif
 
@@ -485,7 +523,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	 * empty and thus can be converted
 	 */
 	potential_mask = slice_mask_for_free(mm);
-	or_mask(potential_mask, good_mask);
+	slice_or_mask(&potential_mask, &good_mask);
 	slice_print_mask(" potential", potential_mask);
 
 	if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
@@ -518,7 +556,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 #ifdef CONFIG_PPC_64K_PAGES
 	if (addr == -ENOMEM && psize == MMU_PAGE_64K) {
 		/* retry the search with 4k-page slices included */
-		or_mask(potential_mask, compat_mask);
+		slice_or_mask(&potential_mask, &compat_mask);
 		addr = slice_find_area(mm, len, potential_mask, psize,
 				       topdown);
 	}
@@ -532,8 +570,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	slice_print_mask(" mask", mask);
 
  convert:
-	andnot_mask(mask, good_mask);
-	andnot_mask(mask, compat_mask);
+	slice_andnot_mask(&mask, &good_mask);
+	slice_andnot_mask(&mask, &compat_mask);
 	if (mask.low_slices || mask.high_slices) {
 		slice_convert(mm, mask, psize);
 		if (psize > MMU_PAGE_BASE)
@@ -701,7 +739,7 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 	if (psize == MMU_PAGE_64K) {
 		struct slice_mask compat_mask;
 		compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
-		or_mask(available, compat_mask);
+		slice_or_mask(&available, &compat_mask);
 	}
 #endif
 
-- 
2.7.4

Re: [PATCH V3 01/10] powerpc/mm/slice: Convert slice_mask high slice to a bitmap

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:08PM +0530, Aneesh Kumar K.V wrote:
> In followup patch we want to increase the va range which will result
> in us requiring high_slices to have more than 64 bits. To enable this
> convert high_slices to bitmap. We keep the number bits same in this patch
> and later change that to higher value
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---

For consistency it would be nice to have low_slices represented similarly
as well.

Acked-by: Balbir Singh <bsingharora@gmail.com>

Re: [PATCH V3 01/10] powerpc/mm/slice: Convert slice_mask high slice to a bitmap

[Aneesh Kumar K.V]

On Tuesday 21 February 2017 10:13 AM, Balbir Singh wrote:
> On Sun, Feb 19, 2017 at 03:37:08PM +0530, Aneesh Kumar K.V wrote:
>> In followup patch we want to increase the va range which will result
>> in us requiring high_slices to have more than 64 bits. To enable this
>> convert high_slices to bitmap. We keep the number bits same in this patch
>> and later change that to higher value
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
> For consistency it would be nice to have low_slices represented similarly
> as well.

That will need converting lot of low_slices update to bitmap api with no 
real benefit
> Acked-by: Balbir Singh <bsingharora@gmail.com>
>

-aneesh

Re: [PATCH V3 01/10] powerpc/mm/slice: Convert slice_mask high slice to a bitmap

[Balbir Singh]

On Tue, Feb 21, 2017 at 12:26:15PM +0530, Aneesh Kumar K.V wrote:
> 
> 
> On Tuesday 21 February 2017 10:13 AM, Balbir Singh wrote:
> > On Sun, Feb 19, 2017 at 03:37:08PM +0530, Aneesh Kumar K.V wrote:
> > > In followup patch we want to increase the va range which will result
> > > in us requiring high_slices to have more than 64 bits. To enable this
> > > convert high_slices to bitmap. We keep the number bits same in this patch
> > > and later change that to higher value
> > > 
> > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> > > ---
> > For consistency it would be nice to have low_slices represented similarly
> > as well.
> 
> That will need converting lot of low_slices update to bitmap api with no
> real benefit

Consistency and not having our own bitmap implementation :) Anways,
I am not too held up on it.

> > Acked-by: Balbir Singh <bsingharora@gmail.com>
> > 
> 
> -aneesh
> 

[PATCH V3 02/10] powerpc/mm/slice: Update the function prototype

[Aneesh Kumar K.V]

This avoid copying the slice_mask struct as function return value

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/slice.c | 62 ++++++++++++++++++++++---------------------------
 1 file changed, 28 insertions(+), 34 deletions(-)

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index c4e718e38a03..1cb0e98e70c0 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -75,20 +75,19 @@ static void slice_print_mask(const char *label, struct slice_mask mask) {}
 
 #endif
 
-static struct slice_mask slice_range_to_mask(unsigned long start,
-					     unsigned long len)
+static void slice_range_to_mask(unsigned long start, unsigned long len,
+				struct slice_mask *ret)
 {
 	unsigned long end = start + len - 1;
-	struct slice_mask ret;
 
-	ret.low_slices = 0;
-	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
+	ret->low_slices = 0;
+	bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	if (start < SLICE_LOW_TOP) {
 		unsigned long mend = min(end, SLICE_LOW_TOP);
 		unsigned long mstart = min(start, SLICE_LOW_TOP);
 
-		ret.low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
+		ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
 			- (1u << GET_LOW_SLICE_INDEX(mstart));
 	}
 
@@ -97,9 +96,8 @@ static struct slice_mask slice_range_to_mask(unsigned long start,
 		unsigned long align_end = ALIGN(end, (1UL <<SLICE_HIGH_SHIFT));
 		unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
 
-		bitmap_set(ret.high_slices, start_index, count);
+		bitmap_set(ret->high_slices, start_index, count);
 	}
-	return ret;
 }
 
 static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
@@ -133,53 +131,47 @@ static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
 	return !slice_area_is_free(mm, start, end - start);
 }
 
-static struct slice_mask slice_mask_for_free(struct mm_struct *mm)
+static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret)
 {
-	struct slice_mask ret;
 	unsigned long i;
 
-	ret.low_slices = 0;
-	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
+	ret->low_slices = 0;
+	bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	for (i = 0; i < SLICE_NUM_LOW; i++)
 		if (!slice_low_has_vma(mm, i))
-			ret.low_slices |= 1u << i;
+			ret->low_slices |= 1u << i;
 
 	if (mm->task_size <= SLICE_LOW_TOP)
-		return ret;
+		return;
 
 	for (i = 0; i < SLICE_NUM_HIGH; i++)
 		if (!slice_high_has_vma(mm, i))
-			__set_bit(i, ret.high_slices);
-
-	return ret;
+			__set_bit(i, ret->high_slices);
 }
 
-static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
+static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_mask *ret)
 {
 	unsigned char *hpsizes;
 	int index, mask_index;
-	struct slice_mask ret;
 	unsigned long i;
 	u64 lpsizes;
 
-	ret.low_slices = 0;
-	bitmap_zero(ret.high_slices, SLICE_NUM_HIGH);
+	ret->low_slices = 0;
+	bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	lpsizes = mm->context.low_slices_psize;
 	for (i = 0; i < SLICE_NUM_LOW; i++)
 		if (((lpsizes >> (i * 4)) & 0xf) == psize)
-			ret.low_slices |= 1u << i;
+			ret->low_slices |= 1u << i;
 
 	hpsizes = mm->context.high_slices_psize;
 	for (i = 0; i < SLICE_NUM_HIGH; i++) {
 		mask_index = i & 0x1;
 		index = i >> 1;
 		if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
-			__set_bit(i, ret.high_slices);
+			__set_bit(i, ret->high_slices);
 	}
-
-	return ret;
 }
 
 static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
@@ -461,7 +453,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	/* First make up a "good" mask of slices that have the right size
 	 * already
 	 */
-	good_mask = slice_mask_for_size(mm, psize);
+	slice_mask_for_size(mm, psize, &good_mask);
 	slice_print_mask(" good_mask", good_mask);
 
 	/*
@@ -486,7 +478,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 #ifdef CONFIG_PPC_64K_PAGES
 	/* If we support combo pages, we can allow 64k pages in 4k slices */
 	if (psize == MMU_PAGE_64K) {
-		compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
+		slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask);
 		if (fixed)
 			slice_or_mask(&good_mask, &compat_mask);
 	}
@@ -495,7 +487,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	/* First check hint if it's valid or if we have MAP_FIXED */
 	if (addr != 0 || fixed) {
 		/* Build a mask for the requested range */
-		mask = slice_range_to_mask(addr, len);
+		slice_range_to_mask(addr, len, &mask);
 		slice_print_mask(" mask", mask);
 
 		/* Check if we fit in the good mask. If we do, we just return,
@@ -522,7 +514,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	/* We don't fit in the good mask, check what other slices are
 	 * empty and thus can be converted
 	 */
-	potential_mask = slice_mask_for_free(mm);
+	slice_mask_for_free(mm, &potential_mask);
 	slice_or_mask(&potential_mask, &good_mask);
 	slice_print_mask(" potential", potential_mask);
 
@@ -565,7 +557,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	if (addr == -ENOMEM)
 		return -ENOMEM;
 
-	mask = slice_range_to_mask(addr, len);
+	slice_range_to_mask(addr, len, &mask);
 	slice_dbg(" found potential area at 0x%lx\n", addr);
 	slice_print_mask(" mask", mask);
 
@@ -697,9 +689,11 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 			   unsigned long len, unsigned int psize)
 {
-	struct slice_mask mask = slice_range_to_mask(start, len);
+	struct slice_mask mask;
 
 	VM_BUG_ON(radix_enabled());
+
+	slice_range_to_mask(start, len, &mask);
 	slice_convert(mm, mask, psize);
 }
 
@@ -732,13 +726,13 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 	if (radix_enabled())
 		return 0;
 
-	mask = slice_range_to_mask(addr, len);
-	available = slice_mask_for_size(mm, psize);
+	slice_range_to_mask(addr, len, &mask);
+	slice_mask_for_size(mm, psize, &available);
 #ifdef CONFIG_PPC_64K_PAGES
 	/* We need to account for 4k slices too */
 	if (psize == MMU_PAGE_64K) {
 		struct slice_mask compat_mask;
-		compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
+		slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask);
 		slice_or_mask(&available, &compat_mask);
 	}
 #endif
-- 
2.7.4

Re: [PATCH V3 02/10] powerpc/mm/slice: Update the function prototype

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:09PM +0530, Aneesh Kumar K.V wrote:
> This avoid copying the slice_mask struct as function return value
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---

Makes sense, since we are no longer restricted to u64

Acked-by: Balbir Singh <bsingharora@gmail.com>

[PATCH V3 03/10] powerpc/mm/hash: Move kernel context to the starting of context range

[Aneesh Kumar K.V]

With current kernel, we use the top 4 context for the kernel. Kernel VSIDs are built
using these top context values and effective segemnt ID. In the following patches,
we want to increase the max effective address to 512TB. We achieve that by
increasing the effective segments IDs there by increasing virtual address range.

We will be switching to a 68bit virtual address in the following patch. But for
platforms like  p4 and p5, which only support a 65 bit va, we want to limit the
virtual addrress to a 65 bit value. We do that by limiting the context bits to 16
instead of 19. That means we will have different max context values on different
platforms.

To make this simpler. we move the kernel context to the starting of the range.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h | 39 ++++++------
 arch/powerpc/include/asm/mmu_context.h        |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_host.c         |  2 +-
 arch/powerpc/mm/hash_utils_64.c               |  5 --
 arch/powerpc/mm/mmu_context_book3s64.c        | 88 ++++++++++++++++++---------
 arch/powerpc/mm/slb_low.S                     | 20 ++----
 6 files changed, 84 insertions(+), 72 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index 0735d5a8049f..014a9bb197cd 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -493,10 +493,10 @@ extern void slb_set_size(u16 size);
  * For user processes max context id is limited to ((1ul << 19) - 5)
  * for kernel space, we use the top 4 context ids to map address as below
  * NOTE: each context only support 64TB now.
- * 0x7fffc -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
- * 0x7fffd -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
- * 0x7fffe -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
- * 0x7ffff -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
+ * 0x00000 -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
+ * 0x00001 -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
+ * 0x00002 -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
+ * 0x00003 -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
  *
  * The proto-VSIDs are then scrambled into real VSIDs with the
  * multiplicative hash:
@@ -510,15 +510,9 @@ extern void slb_set_size(u16 size);
  * robust scattering in the hash table (at least based on some initial
  * results).
  *
- * We also consider VSID 0 special. We use VSID 0 for slb entries mapping
- * bad address. This enables us to consolidate bad address handling in
- * hash_page.
- *
  * We also need to avoid the last segment of the last context, because that
  * would give a protovsid of 0x1fffffffff. That will result in a VSID 0
- * because of the modulo operation in vsid scramble. But the vmemmap
- * (which is what uses region 0xf) will never be close to 64TB in size
- * (it's 56 bytes per page of system memory).
+ * because of the modulo operation in vsid scramble.
  */
 
 #define CONTEXT_BITS		19
@@ -530,12 +524,15 @@ extern void slb_set_size(u16 size);
 /*
  * 256MB segment
  * The proto-VSID space has 2^(CONTEX_BITS + ESID_BITS) - 1 segments
- * available for user + kernel mapping. The top 4 contexts are used for
+ * available for user + kernel mapping. The bottom 4 contexts are used for
  * kernel mapping. Each segment contains 2^28 bytes. Each
- * context maps 2^46 bytes (64TB) so we can support 2^19-1 contexts
- * (19 == 37 + 28 - 46).
+ * context maps 2^46 bytes (64TB).
+ *
+ * We also need to avoid the last segment of the last context, because that
+ * would give a protovsid of 0x1fffffffff. That will result in a VSID 0
+ * because of the modulo operation in vsid scramble.
  */
-#define MAX_USER_CONTEXT	((ASM_CONST(1) << CONTEXT_BITS) - 5)
+#define MAX_USER_CONTEXT	((ASM_CONST(1) << CONTEXT_BITS) - 2)
 
 /*
  * This should be computed such that protovosid * vsid_mulitplier
@@ -671,19 +668,19 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
  * This is only valid for addresses >= PAGE_OFFSET
  *
  * For kernel space, we use the top 4 context ids to map address as below
- * 0x7fffc -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
- * 0x7fffd -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
- * 0x7fffe -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
- * 0x7ffff -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
+ * 0x00000 -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
+ * 0x00001 -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
+ * 0x00002 -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
+ * 0x00003 -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
  */
 static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
 {
 	unsigned long context;
 
 	/*
-	 * kernel take the top 4 context from the available range
+	 * kernel take the first 4 context from the available range
 	 */
-	context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1;
+	context = (ea >> 60) - 0xc;
 	return get_vsid(context, ea, ssize);
 }
 
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index b9e3f0aca261..8fe1ba1808d3 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -51,7 +51,7 @@ static inline void switch_mmu_context(struct mm_struct *prev,
 	return switch_slb(tsk, next);
 }
 
-extern int __init_new_context(void);
+extern int hash__get_new_context(void);
 extern void __destroy_context(int context_id);
 static inline void mmu_context_init(void) { }
 #else
diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index a587e8f4fd26..d6041101a5e2 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -390,7 +390,7 @@ int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
 	struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
 	int err;
 
-	err = __init_new_context();
+	err = hash__get_new_context();
 	if (err < 0)
 		return -1;
 	vcpu3s->context_id[0] = err;
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 67e19a0821be..978314b6b8d7 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -255,11 +255,6 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 		unsigned long vpn  = hpt_vpn(vaddr, vsid, ssize);
 		unsigned long tprot = prot;
 
-		/*
-		 * If we hit a bad address return error.
-		 */
-		if (!vsid)
-			return -1;
 		/* Make kernel text executable */
 		if (overlaps_kernel_text(vaddr, vaddr + step))
 			tprot &= ~HPTE_R_N;
diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index 73bf6e14c3aa..a6450c7f9cf3 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -30,17 +30,19 @@
 static DEFINE_SPINLOCK(mmu_context_lock);
 static DEFINE_IDA(mmu_context_ida);
 
-int __init_new_context(void)
+int hash__get_new_context(void)
 {
-	int index;
-	int err;
+	int index, err;
 
 again:
 	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
 		return -ENOMEM;
 
 	spin_lock(&mmu_context_lock);
-	err = ida_get_new_above(&mmu_context_ida, 1, &index);
+	/*
+	 * 0 - 3 context is taken by kernel.
+	 */
+	err = ida_get_new_above(&mmu_context_ida, 4, &index);
 	spin_unlock(&mmu_context_lock);
 
 	if (err == -EAGAIN)
@@ -54,51 +56,79 @@ int __init_new_context(void)
 		spin_unlock(&mmu_context_lock);
 		return -ENOMEM;
 	}
+	return index;
+}
+EXPORT_SYMBOL_GPL(hash__get_new_context);
+
+static int hash__init_new_context(struct mm_struct *mm)
+{
+	int index;
 
+	index = hash__get_new_context();
+	if (index < 0)
+		return index;
+	/* The old code would re-promote on fork, we don't do that
+	 * when using slices as it could cause problem promoting slices
+	 * that have been forced down to 4K
+	 *
+	 * For book3s we have MMU_NO_CONTEXT set to be ~0. Hence check
+	 * explicitly against context.id == 0. This ensures that we
+	 * properly initialize context slice details for newly allocated
+	 * mm's (which will have id == 0) and don't alter context slice
+	 * inherited via fork (which will have id != 0).
+	 *
+	 * We should not be calling init_new_context() on init_mm. Hence a
+	 * check against 0 is ok.
+	 */
+	if (mm->context.id == 0)
+		slice_set_user_psize(mm, mmu_virtual_psize);
+	subpage_prot_init_new_context(mm);
 	return index;
 }
-EXPORT_SYMBOL_GPL(__init_new_context);
-static int radix__init_new_context(struct mm_struct *mm, int index)
+
+static int radix__init_new_context(struct mm_struct *mm)
 {
+	int index, err;
 	unsigned long rts_field;
 
+again:
+	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
+		return -ENOMEM;
+
+	spin_lock(&mmu_context_lock);
+	err = ida_get_new_above(&mmu_context_ida, 1, &index);
+	spin_unlock(&mmu_context_lock);
+
+	if (err == -EAGAIN)
+		goto again;
+	else if (err)
+		return err;
+
+	if (index > ((1UL << PRTB_SIZE_SHIFT) - 1)) {
+		spin_lock(&mmu_context_lock);
+		ida_remove(&mmu_context_ida, index);
+		spin_unlock(&mmu_context_lock);
+		return -ENOMEM;
+	}
 	/*
 	 * set the process table entry,
 	 */
 	rts_field = radix__get_tree_size();
 	process_tb[index].prtb0 = cpu_to_be64(rts_field | __pa(mm->pgd) | RADIX_PGD_INDEX_SIZE);
-	return 0;
+	return index;
 }
 
 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
 	int index;
 
-	index = __init_new_context();
+	if (radix_enabled())
+		index = radix__init_new_context(mm);
+	else
+		index = hash__init_new_context(mm);
 	if (index < 0)
 		return index;
 
-	if (radix_enabled()) {
-		radix__init_new_context(mm, index);
-	} else {
-
-		/* The old code would re-promote on fork, we don't do that
-		 * when using slices as it could cause problem promoting slices
-		 * that have been forced down to 4K
-		 *
-		 * For book3s we have MMU_NO_CONTEXT set to be ~0. Hence check
-		 * explicitly against context.id == 0. This ensures that we
-		 * properly initialize context slice details for newly allocated
-		 * mm's (which will have id == 0) and don't alter context slice
-		 * inherited via fork (which will have id != 0).
-		 *
-		 * We should not be calling init_new_context() on init_mm. Hence a
-		 * check against 0 is ok.
-		 */
-		if (mm->context.id == 0)
-			slice_set_user_psize(mm, mmu_virtual_psize);
-		subpage_prot_init_new_context(mm);
-	}
 	mm->context.id = index;
 #ifdef CONFIG_PPC_ICSWX
 	mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index e2974fcd20f1..4ce050ea4200 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -45,13 +45,6 @@ _GLOBAL(slb_allocate_realmode)
 	/* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */
 	blt	cr7,0f			/* user or kernel? */
 
-	/* kernel address: proto-VSID = ESID */
-	/* WARNING - MAGIC: we don't use the VSID 0xfffffffff, but
-	 * this code will generate the protoVSID 0xfffffffff for the
-	 * top segment.  That's ok, the scramble below will translate
-	 * it to VSID 0, which is reserved as a bad VSID - one which
-	 * will never have any pages in it.  */
-
 	/* Check if hitting the linear mapping or some other kernel space
 	*/
 	bne	cr7,1f
@@ -63,12 +56,10 @@ _GLOBAL(slb_allocate_realmode)
 slb_miss_kernel_load_linear:
 	li	r11,0
 	/*
-	 * context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
+	 * context = (ea >> 60) - 0xc
 	 * r9 = region id.
 	 */
-	addis	r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha
-	addi	r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l
-
+	subi	r9,r9,0xc
 
 BEGIN_FTR_SECTION
 	b	slb_finish_load
@@ -77,9 +68,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
 
 1:
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-	/* Check virtual memmap region. To be patches at kernel boot */
 	cmpldi	cr0,r9,0xf
 	bne	1f
+/* Check virtual memmap region. To be patched at kernel boot */
 .globl slb_miss_kernel_load_vmemmap
 slb_miss_kernel_load_vmemmap:
 	li	r11,0
@@ -102,11 +93,10 @@ slb_miss_kernel_load_io:
 	li	r11,0
 6:
 	/*
-	 * context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
+	 * context = (ea >> 60) - 0xc
 	 * r9 = region id.
 	 */
-	addis	r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha
-	addi	r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l
+	subi	r9,r9,0xc
 
 BEGIN_FTR_SECTION
 	b	slb_finish_load
-- 
2.7.4

Re: [PATCH V3 03/10] powerpc/mm/hash: Move kernel context to the starting of context range

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:10PM +0530, Aneesh Kumar K.V wrote:
> With current kernel, we use the top 4 context for the kernel. Kernel VSIDs are built
> using these top context values and effective segemnt ID. In the following patches,
> we want to increase the max effective address to 512TB. We achieve that by
> increasing the effective segments IDs there by increasing virtual address range.
> 
> We will be switching to a 68bit virtual address in the following patch. But for
> platforms like  p4 and p5, which only support a 65 bit va, we want to limit the
> virtual addrress to a 65 bit value. We do that by limiting the context bits to 16
> instead of 19. That means we will have different max context values on different
> platforms.
> 
> To make this simpler. we move the kernel context to the starting of the range.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---

Acked-by: Balbir Singh <bsingharora@gmail.com>

[PATCH V3 04/10] powerpc/mm/hash: Support 68 bit VA

[Aneesh Kumar K.V]

Inorder to support large effective address range (512TB), we want to increase
the virtual address bits to 68. But we do have platforms like p4 and p5 that can
only do 65 bit VA. We support those platforms by limiting context bits on them
to 16.

The protovsid -> vsid conversion is verified to work with both 65 and 68 bit
va values. I also documented the restrictions in a table format as part of code
comments.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h | 123 ++++++++++++++++----------
 arch/powerpc/include/asm/mmu.h                |  19 ++--
 arch/powerpc/kvm/book3s_64_mmu_host.c         |   8 +-
 arch/powerpc/mm/mmu_context_book3s64.c        |   8 +-
 arch/powerpc/mm/slb_low.S                     |  54 +++++++++--
 5 files changed, 150 insertions(+), 62 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index 014a9bb197cd..97ccd8ae6c75 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -39,6 +39,7 @@
 
 /* Bits in the SLB VSID word */
 #define SLB_VSID_SHIFT		12
+#define SLB_VSID_SHIFT_256M	12
 #define SLB_VSID_SHIFT_1T	24
 #define SLB_VSID_SSIZE_SHIFT	62
 #define SLB_VSID_B		ASM_CONST(0xc000000000000000)
@@ -515,9 +516,19 @@ extern void slb_set_size(u16 size);
  * because of the modulo operation in vsid scramble.
  */
 
+/*
+ * Max Va bits we support as of now is 68 bits. We want 19 bit
+ * context ID.
+ * Restrictions:
+ * GPU has restrictions of not able to access beyond 128TB
+ * (47 bit effective address). We also cannot do more than 20bit PID.
+ * For p4 and p5 which can only do 65 bit VA, we restrict our CONTEXT_BITS
+ * to 16 bits (ie, we can only have 2^16 pids at the same time).
+ */
+#define VA_BITS			68
 #define CONTEXT_BITS		19
-#define ESID_BITS		18
-#define ESID_BITS_1T		6
+#define ESID_BITS		(VA_BITS - (SID_SHIFT + CONTEXT_BITS))
+#define ESID_BITS_1T		(VA_BITS - (SID_SHIFT_1T + CONTEXT_BITS))
 
 #define ESID_BITS_MASK		((1 << ESID_BITS) - 1)
 #define ESID_BITS_1T_MASK	((1 << ESID_BITS_1T) - 1)
@@ -526,62 +537,54 @@ extern void slb_set_size(u16 size);
  * The proto-VSID space has 2^(CONTEX_BITS + ESID_BITS) - 1 segments
  * available for user + kernel mapping. The bottom 4 contexts are used for
  * kernel mapping. Each segment contains 2^28 bytes. Each
- * context maps 2^46 bytes (64TB).
+ * context maps 2^49 bytes (512TB).
  *
  * We also need to avoid the last segment of the last context, because that
  * would give a protovsid of 0x1fffffffff. That will result in a VSID 0
  * because of the modulo operation in vsid scramble.
  */
 #define MAX_USER_CONTEXT	((ASM_CONST(1) << CONTEXT_BITS) - 2)
+/*
+ * For platforms that support on 65bit VA we limit the context bits
+ */
+#define MAX_USER_CONTEXT_65BIT_VA ((ASM_CONST(1) << (65 - (SID_SHIFT + ESID_BITS))) - 2)
 
 /*
  * This should be computed such that protovosid * vsid_mulitplier
  * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
+ * We also need to make sure that number of bits in divisor is less
+ * than twice the number of protovsid bits for our modulus optmization to work.
+ * The below table shows the current values used.
+ *
+ * |-------+------------+----------------+------------+--------------|
+ * |       | Prime Bits | VSID_BITS_65VA | Total Bits | 2* VSID_BITS |
+ * |-------+------------+----------------+------------+--------------|
+ * | 1T    |         24 |             25 |         49 |           50 |
+ * |-------+------------+----------------+------------+--------------|
+ * | 256MB |         24 |             37 |         61 |           74 |
+ * |-------+------------+----------------+------------+--------------|
+ *
+ * |-------+------------+----------------+------------+--------------|
+ * |       | Prime Bits | VSID_BITS_68VA | Total Bits | 2* VSID_BITS |
+ * |-------+------------+----------------+------------+--------------|
+ * | 1T    |         24 |             28 |         52 |           56 |
+ * |-------+------------+----------------+------------+--------------|
+ * | 256MB |         24 |             40 |         64 |           80 |
+ * |-------+------------+----------------+------------+--------------|
+ *
  */
 #define VSID_MULTIPLIER_256M	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_256M		(CONTEXT_BITS + ESID_BITS)
+#define VSID_BITS_256M		(VA_BITS - SID_SHIFT)
 #define VSID_MODULUS_256M	((1UL<<VSID_BITS_256M)-1)
+#define VSID_BITS_65_256M	(65 - SID_SHIFT)
 
 #define VSID_MULTIPLIER_1T	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_1T		(CONTEXT_BITS + ESID_BITS_1T)
+#define VSID_BITS_1T		(VA_BITS - SID_SHIFT_1T)
 #define VSID_MODULUS_1T		((1UL<<VSID_BITS_1T)-1)
-
+#define VSID_BITS_65_1T		(65 - SID_SHIFT_1T)
 
 #define USER_VSID_RANGE	(1UL << (ESID_BITS + SID_SHIFT))
 
-/*
- * This macro generates asm code to compute the VSID scramble
- * function.  Used in slb_allocate() and do_stab_bolted.  The function
- * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
- *
- *	rt = register containing the proto-VSID and into which the
- *		VSID will be stored
- *	rx = scratch register (clobbered)
- *
- * 	- rt and rx must be different registers
- * 	- The answer will end up in the low VSID_BITS bits of rt.  The higher
- * 	  bits may contain other garbage, so you may need to mask the
- * 	  result.
- */
-#define ASM_VSID_SCRAMBLE(rt, rx, size)					\
-	lis	rx,VSID_MULTIPLIER_##size@h;				\
-	ori	rx,rx,VSID_MULTIPLIER_##size@l;				\
-	mulld	rt,rt,rx;		/* rt = rt * MULTIPLIER */	\
-									\
-	srdi	rx,rt,VSID_BITS_##size;					\
-	clrldi	rt,rt,(64-VSID_BITS_##size);				\
-	add	rt,rt,rx;		/* add high and low bits */	\
-	/* NOTE: explanation based on VSID_BITS_##size = 36		\
-	 * Now, r3 == VSID (mod 2^36-1), and lies between 0 and		\
-	 * 2^36-1+2^28-1.  That in particular means that if r3 >=	\
-	 * 2^36-1, then r3+1 has the 2^36 bit set.  So, if r3+1 has	\
-	 * the bit clear, r3 already has the answer we want, if it	\
-	 * doesn't, the answer is the low 36 bits of r3+1.  So in all	\
-	 * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
-	addi	rx,rt,1;						\
-	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
-	add	rt,rt,rx
-
 /* 4 bits per slice and we have one slice per 1TB */
 #define SLICE_ARRAY_SIZE  (H_PGTABLE_RANGE >> 41)
 
@@ -629,7 +632,7 @@ static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }
 #define vsid_scramble(protovsid, size) \
 	((((protovsid) * VSID_MULTIPLIER_##size) % VSID_MODULUS_##size))
 
-#else /* 1 */
+/* simplified form avoiding mod operation */
 #define vsid_scramble(protovsid, size) \
 	({								 \
 		unsigned long x;					 \
@@ -637,6 +640,21 @@ static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }
 		x = (x >> VSID_BITS_##size) + (x & VSID_MODULUS_##size); \
 		(x + ((x+1) >> VSID_BITS_##size)) & VSID_MODULUS_##size; \
 	})
+
+#else /* 1 */
+static inline unsigned long vsid_scramble(unsigned long protovsid,
+				  unsigned long vsid_multiplier, int vsid_bits)
+{
+	unsigned long vsid;
+	unsigned long vsid_modulus = ((1UL << vsid_bits) - 1);
+	/*
+	 * We have same multipler for both 256 and 1T segements now
+	 */
+	vsid = protovsid * vsid_multiplier;
+	vsid = (vsid >> vsid_bits) + (vsid & vsid_modulus);
+	return (vsid + ((vsid + 1) >> vsid_bits)) & vsid_modulus;
+}
+
 #endif /* 1 */
 
 /* Returns the segment size indicator for a user address */
@@ -651,17 +669,32 @@ static inline int user_segment_size(unsigned long addr)
 static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
 				     int ssize)
 {
+	unsigned long va_bits = VA_BITS;
+	unsigned long vsid_bits;
+	unsigned long protovsid;
+
 	/*
 	 * Bad address. We return VSID 0 for that
 	 */
 	if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
 		return 0;
 
-	if (ssize == MMU_SEGSIZE_256M)
-		return vsid_scramble((context << ESID_BITS)
-				     | ((ea >> SID_SHIFT) & ESID_BITS_MASK), 256M);
-	return vsid_scramble((context << ESID_BITS_1T)
-			     | ((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK), 1T);
+	if (!mmu_has_feature(MMU_FTR_68_BIT_VA))
+		va_bits = 65;
+
+	if (ssize == MMU_SEGSIZE_256M) {
+		vsid_bits = va_bits - SID_SHIFT;
+		protovsid = (context << ESID_BITS) |
+			((ea >> SID_SHIFT) & ESID_BITS_MASK);
+		return vsid_scramble(protovsid,
+				     VSID_MULTIPLIER_256M, vsid_bits);
+	}
+	/* 1T segment */
+	vsid_bits = va_bits - SID_SHIFT_1T;
+	protovsid = (context << ESID_BITS_1T) |
+		((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK);
+	return vsid_scramble(protovsid,
+			     VSID_MULTIPLIER_1T, vsid_bits);
 }
 
 /*
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 065e762fae85..78260409dc9c 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -29,6 +29,10 @@
  */
 
 /*
+ * Support for 68 bit VA space. We added that from ISA 2.05
+ */
+#define MMU_FTR_68_BIT_VA		ASM_CONST(0x00002000)
+/*
  * Kernel read only support.
  * We added the ppp value 0b110 in ISA 2.04.
  */
@@ -109,10 +113,10 @@
 #define MMU_FTRS_POWER4		MMU_FTRS_DEFAULT_HPTE_ARCH_V2
 #define MMU_FTRS_PPC970		MMU_FTRS_POWER4 | MMU_FTR_TLBIE_CROP_VA
 #define MMU_FTRS_POWER5		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
-#define MMU_FTRS_POWER6		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
-#define MMU_FTRS_POWER7		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
-#define MMU_FTRS_POWER8		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
-#define MMU_FTRS_POWER9		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
+#define MMU_FTRS_POWER6		MMU_FTRS_POWER5 | MMU_FTR_KERNEL_RO | MMU_FTR_68_BIT_VA
+#define MMU_FTRS_POWER7		MMU_FTRS_POWER6
+#define MMU_FTRS_POWER8		MMU_FTRS_POWER6
+#define MMU_FTRS_POWER9		MMU_FTRS_POWER6
 #define MMU_FTRS_CELL		MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
 				MMU_FTR_CI_LARGE_PAGE
 #define MMU_FTRS_PA6T		MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
@@ -136,7 +140,7 @@ enum {
 		MMU_FTR_NO_SLBIE_B | MMU_FTR_16M_PAGE | MMU_FTR_TLBIEL |
 		MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_CI_LARGE_PAGE |
 		MMU_FTR_1T_SEGMENT | MMU_FTR_TLBIE_CROP_VA |
-		MMU_FTR_KERNEL_RO |
+		MMU_FTR_KERNEL_RO | MMU_FTR_68_BIT_VA |
 #ifdef CONFIG_PPC_RADIX_MMU
 		MMU_FTR_TYPE_RADIX |
 #endif
@@ -290,7 +294,10 @@ static inline bool early_radix_enabled(void)
 #define MMU_PAGE_16G	14
 #define MMU_PAGE_64G	15
 
-/* N.B. we need to change the type of hpte_page_sizes if this gets to be > 16 */
+/*
+ * N.B. we need to change the type of hpte_page_sizes if this gets to be > 16
+ * Also we need to change he type of mm_context.low/high_slices_psize.
+ */
 #define MMU_PAGE_COUNT	16
 
 #ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index d6041101a5e2..bed699ab7654 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -229,6 +229,7 @@ void kvmppc_mmu_unmap_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
 
 static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
 {
+	unsigned long vsid_bits = VSID_BITS_65_256M;
 	struct kvmppc_sid_map *map;
 	struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
 	u16 sid_map_mask;
@@ -257,7 +258,12 @@ static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
 		kvmppc_mmu_pte_flush(vcpu, 0, 0);
 		kvmppc_mmu_flush_segments(vcpu);
 	}
-	map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++, 256M);
+
+	if (mmu_has_feature(MMU_FTR_68_BIT_VA))
+		vsid_bits = VSID_BITS_256M;
+
+	map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++,
+				       VSID_MULTIPLIER_256M, vsid_bits);
 
 	map->guest_vsid = gvsid;
 	map->valid = true;
diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index a6450c7f9cf3..e6a5bcbf8abe 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -33,6 +33,12 @@ static DEFINE_IDA(mmu_context_ida);
 int hash__get_new_context(void)
 {
 	int index, err;
+	unsigned long max_user_context;
+
+	if (mmu_has_feature(MMU_FTR_68_BIT_VA))
+		max_user_context = MAX_USER_CONTEXT;
+	else
+		max_user_context = MAX_USER_CONTEXT_65BIT_VA;
 
 again:
 	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
@@ -50,7 +56,7 @@ int hash__get_new_context(void)
 	else if (err)
 		return err;
 
-	if (index > MAX_USER_CONTEXT) {
+	if (index > max_user_context) {
 		spin_lock(&mmu_context_lock);
 		ida_remove(&mmu_context_ida, index);
 		spin_unlock(&mmu_context_lock);
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index 4ce050ea4200..bb75a667483e 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -23,6 +23,48 @@
 #include <asm/pgtable.h>
 #include <asm/firmware.h>
 
+/*
+ * This macro generates asm code to compute the VSID scramble
+ * function.  Used in slb_allocate() and do_stab_bolted.  The function
+ * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
+ *
+ *	rt = register containing the proto-VSID and into which the
+ *		VSID will be stored
+ *	rx = scratch register (clobbered)
+ *	rf = flags
+ *
+ *	- rt and rx must be different registers
+ *	- The answer will end up in the low VSID_BITS bits of rt.  The higher
+ *	  bits may contain other garbage, so you may need to mask the
+ *	  result.
+ */
+#define ASM_VSID_SCRAMBLE(rt, rx, rf, size)				\
+	lis	rx,VSID_MULTIPLIER_##size@h;				\
+	ori	rx,rx,VSID_MULTIPLIER_##size@l;				\
+	mulld	rt,rt,rx;		/* rt = rt * MULTIPLIER */	\
+/*									\
+ * powermac get slb fault before feature fixup, so make 65 bit part     \
+ * the default part of feature fixup					\
+ */									\
+BEGIN_MMU_FTR_SECTION							\
+	srdi	rx,rt,VSID_BITS_65_##size;				\
+	clrldi	rt,rt,(64-VSID_BITS_65_##size);				\
+	add	rt,rt,rx;						\
+	addi	rx,rt,1;						\
+	srdi	rx,rx,VSID_BITS_65_##size;				\
+	add	rt,rt,rx;						\
+	rldimi	rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_65_##size)); \
+MMU_FTR_SECTION_ELSE							\
+	srdi	rx,rt,VSID_BITS_##size;					\
+	clrldi	rt,rt,(64-VSID_BITS_##size);				\
+	add	rt,rt,rx;		/* add high and low bits */	\
+	addi	rx,rt,1;						\
+	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
+	add	rt,rt,rx;						\
+	rldimi	rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_##size)); \
+ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_68_BIT_VA)
+
+
 /* void slb_allocate_realmode(unsigned long ea);
  *
  * Create an SLB entry for the given EA (user or kernel).
@@ -179,13 +221,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
  */
 slb_finish_load:
 	rldimi  r10,r9,ESID_BITS,0
-	ASM_VSID_SCRAMBLE(r10,r9,256M)
-	/*
-	 * bits above VSID_BITS_256M need to be ignored from r10
-	 * also combine VSID and flags
-	 */
-	rldimi	r11,r10,SLB_VSID_SHIFT,(64 - (SLB_VSID_SHIFT + VSID_BITS_256M))
-
+	ASM_VSID_SCRAMBLE(r10,r9,r11,256M)
 	/* r3 = EA, r11 = VSID data */
 	/*
 	 * Find a slot, round robin. Previously we tried to find a
@@ -249,12 +285,12 @@ slb_compare_rr_to_size:
 slb_finish_load_1T:
 	srdi	r10,r10,(SID_SHIFT_1T - SID_SHIFT)	/* get 1T ESID */
 	rldimi  r10,r9,ESID_BITS_1T,0
-	ASM_VSID_SCRAMBLE(r10,r9,1T)
+	ASM_VSID_SCRAMBLE(r10,r9,r11,1T)
 	/*
 	 * bits above VSID_BITS_1T need to be ignored from r10
 	 * also combine VSID and flags
 	 */
-	rldimi	r11,r10,SLB_VSID_SHIFT_1T,(64 - (SLB_VSID_SHIFT_1T + VSID_BITS_1T))
+
 	li	r10,MMU_SEGSIZE_1T
 	rldimi	r11,r10,SLB_VSID_SSIZE_SHIFT,0	/* insert segment size */
 
-- 
2.7.4

Re: [PATCH V3 04/10] powerpc/mm/hash: Support 68 bit VA

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:11PM +0530, Aneesh Kumar K.V wrote:
> Inorder to support large effective address range (512TB), we want to increase
> the virtual address bits to 68. But we do have platforms like p4 and p5 that can
> only do 65 bit VA. We support those platforms by limiting context bits on them
> to 16.
> 
> The protovsid -> vsid conversion is verified to work with both 65 and 68 bit
> va values. I also documented the restrictions in a table format as part of code
> comments.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  /*
>   * This should be computed such that protovosid * vsid_mulitplier
>   * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
> + * We also need to make sure that number of bits in divisor is less
> + * than twice the number of protovsid bits for our modulus optmization to work.

Could you please explain why?

I am also beginning to wonder if we need the modulus optimization.
On my compiler (a * b) % (2^n - 1) generated reasonable code with just
one multiplication and a few shifts and boolean operations.

> + * The below table shows the current values used.
> + *
> + * |-------+------------+----------------+------------+--------------|
> + * |       | Prime Bits | VSID_BITS_65VA | Total Bits | 2* VSID_BITS |
> + * |-------+------------+----------------+------------+--------------|
> + * | 1T    |         24 |             25 |         49 |           50 |
> + * |-------+------------+----------------+------------+--------------|
> + * | 256MB |         24 |             37 |         61 |           74 |
> + * |-------+------------+----------------+------------+--------------|
> + *
> + * |-------+------------+----------------+------------+--------------|
> + * |       | Prime Bits | VSID_BITS_68VA | Total Bits | 2* VSID_BITS |
> + * |-------+------------+----------------+------------+--------------|
> + * | 1T    |         24 |             28 |         52 |           56 |
> + * |-------+------------+----------------+------------+--------------|
> + * | 256MB |         24 |             40 |         64 |           80 |
> + * |-------+------------+----------------+------------+--------------|
> + *
>   */
>  #define VSID_MULTIPLIER_256M	ASM_CONST(12538073)	/* 24-bit prime */
> -#define VSID_BITS_256M		(CONTEXT_BITS + ESID_BITS)
> +#define VSID_BITS_256M		(VA_BITS - SID_SHIFT)
>  #define VSID_MODULUS_256M	((1UL<<VSID_BITS_256M)-1)
> +#define VSID_BITS_65_256M	(65 - SID_SHIFT)
>  
>  #define VSID_MULTIPLIER_1T	ASM_CONST(12538073)	/* 24-bit prime */
> -#define VSID_BITS_1T		(CONTEXT_BITS + ESID_BITS_1T)
> +#define VSID_BITS_1T		(VA_BITS - SID_SHIFT_1T)
>  #define VSID_MODULUS_1T		((1UL<<VSID_BITS_1T)-1)
> -
> +#define VSID_BITS_65_1T		(65 - SID_SHIFT_1T)
>  
>  #define USER_VSID_RANGE	(1UL << (ESID_BITS + SID_SHIFT))
>  
> -/*
> - * This macro generates asm code to compute the VSID scramble
> - * function.  Used in slb_allocate() and do_stab_bolted.  The function
> - * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
> - *
> - *	rt = register containing the proto-VSID and into which the
> - *		VSID will be stored
> - *	rx = scratch register (clobbered)
> - *
> - * 	- rt and rx must be different registers
> - * 	- The answer will end up in the low VSID_BITS bits of rt.  The higher
> - * 	  bits may contain other garbage, so you may need to mask the
> - * 	  result.
> - */
> -#define ASM_VSID_SCRAMBLE(rt, rx, size)					\
> -	lis	rx,VSID_MULTIPLIER_##size@h;				\
> -	ori	rx,rx,VSID_MULTIPLIER_##size@l;				\
> -	mulld	rt,rt,rx;		/* rt = rt * MULTIPLIER */	\
> -									\
> -	srdi	rx,rt,VSID_BITS_##size;					\
> -	clrldi	rt,rt,(64-VSID_BITS_##size);				\
> -	add	rt,rt,rx;		/* add high and low bits */	\
> -	/* NOTE: explanation based on VSID_BITS_##size = 36		\
> -	 * Now, r3 == VSID (mod 2^36-1), and lies between 0 and		\
> -	 * 2^36-1+2^28-1.  That in particular means that if r3 >=	\
> -	 * 2^36-1, then r3+1 has the 2^36 bit set.  So, if r3+1 has	\
> -	 * the bit clear, r3 already has the answer we want, if it	\
> -	 * doesn't, the answer is the low 36 bits of r3+1.  So in all	\
> -	 * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\

I see that this comment is lost in the new definition, could we please
retain it.

> -	addi	rx,rt,1;						\
> -	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
> -	add	rt,rt,rx
> -
>  /* 4 bits per slice and we have one slice per 1TB */
>  #define SLICE_ARRAY_SIZE  (H_PGTABLE_RANGE >> 41)
>  
> @@ -629,7 +632,7 @@ static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }
>  #define vsid_scramble(protovsid, size) \
>  	((((protovsid) * VSID_MULTIPLIER_##size) % VSID_MODULUS_##size))
>  
> -#else /* 1 */
> +/* simplified form avoiding mod operation */
>  #define vsid_scramble(protovsid, size) \
>  	({								 \
>  		unsigned long x;					 \
> @@ -637,6 +640,21 @@ static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }
>  		x = (x >> VSID_BITS_##size) + (x & VSID_MODULUS_##size); \
>  		(x + ((x+1) >> VSID_BITS_##size)) & VSID_MODULUS_##size; \
>  	})
> +
> +static inline unsigned long vsid_scramble(unsigned long protovsid,
> +				  unsigned long vsid_multiplier, int vsid_bits)
> +{
> +	unsigned long vsid;
> +	unsigned long vsid_modulus = ((1UL << vsid_bits) - 1);
> +	/*
> +	 * We have same multipler for both 256 and 1T segements now
> +	 */
> +	vsid = protovsid * vsid_multiplier;
> +	vsid = (vsid >> vsid_bits) + (vsid & vsid_modulus);
> +	return (vsid + ((vsid + 1) >> vsid_bits)) & vsid_modulus;
> +}
> +
>  #endif /* 1 */
>  
>  /* Returns the segment size indicator for a user address */
> @@ -651,17 +669,32 @@ static inline int user_segment_size(unsigned long addr)
>  static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
>  				     int ssize)
>  {
> +	unsigned long va_bits = VA_BITS;

Is there a reason to convert the constant into unsigned long?

> +	unsigned long vsid_bits;
> +	unsigned long protovsid;
> +
>  	/*
>  	 * Bad address. We return VSID 0 for that
>  	 */
>  	if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
>  		return 0;
>  
> -	if (ssize == MMU_SEGSIZE_256M)
> -		return vsid_scramble((context << ESID_BITS)
> -				     | ((ea >> SID_SHIFT) & ESID_BITS_MASK), 256M);
> -	return vsid_scramble((context << ESID_BITS_1T)
> -			     | ((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK), 1T);
> +	if (!mmu_has_feature(MMU_FTR_68_BIT_VA))
> +		va_bits = 65;
> +
> +	if (ssize == MMU_SEGSIZE_256M) {
> +		vsid_bits = va_bits - SID_SHIFT;
> +		protovsid = (context << ESID_BITS) |
> +			((ea >> SID_SHIFT) & ESID_BITS_MASK);
> +		return vsid_scramble(protovsid,
> +				     VSID_MULTIPLIER_256M, vsid_bits);
> +	}
> +	/* 1T segment */
> +	vsid_bits = va_bits - SID_SHIFT_1T;
> +	protovsid = (context << ESID_BITS_1T) |
> +		((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK);
> +	return vsid_scramble(protovsid,
> +			     VSID_MULTIPLIER_1T, vsid_bits);

We seem to be passing an unsigned long to a prototype above that expects
an int

>  }
>  
>  /*
> diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
> index 065e762fae85..78260409dc9c 100644
> --- a/arch/powerpc/include/asm/mmu.h
> +++ b/arch/powerpc/include/asm/mmu.h
> @@ -29,6 +29,10 @@
>   */
>  
>  /*
> + * Support for 68 bit VA space. We added that from ISA 2.05
> + */
> +#define MMU_FTR_68_BIT_VA		ASM_CONST(0x00002000)
> +/*
>   * Kernel read only support.
>   * We added the ppp value 0b110 in ISA 2.04.
>   */
> @@ -109,10 +113,10 @@
>  #define MMU_FTRS_POWER4		MMU_FTRS_DEFAULT_HPTE_ARCH_V2
>  #define MMU_FTRS_PPC970		MMU_FTRS_POWER4 | MMU_FTR_TLBIE_CROP_VA
>  #define MMU_FTRS_POWER5		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
> -#define MMU_FTRS_POWER6		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
> -#define MMU_FTRS_POWER7		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
> -#define MMU_FTRS_POWER8		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
> -#define MMU_FTRS_POWER9		MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
> +#define MMU_FTRS_POWER6		MMU_FTRS_POWER5 | MMU_FTR_KERNEL_RO | MMU_FTR_68_BIT_VA
> +#define MMU_FTRS_POWER7		MMU_FTRS_POWER6
> +#define MMU_FTRS_POWER8		MMU_FTRS_POWER6
> +#define MMU_FTRS_POWER9		MMU_FTRS_POWER6
>  #define MMU_FTRS_CELL		MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
>  				MMU_FTR_CI_LARGE_PAGE
>  #define MMU_FTRS_PA6T		MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
> @@ -136,7 +140,7 @@ enum {
>  		MMU_FTR_NO_SLBIE_B | MMU_FTR_16M_PAGE | MMU_FTR_TLBIEL |
>  		MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_CI_LARGE_PAGE |
>  		MMU_FTR_1T_SEGMENT | MMU_FTR_TLBIE_CROP_VA |
> -		MMU_FTR_KERNEL_RO |
> +		MMU_FTR_KERNEL_RO | MMU_FTR_68_BIT_VA |
>  #ifdef CONFIG_PPC_RADIX_MMU
>  		MMU_FTR_TYPE_RADIX |
>  #endif
> @@ -290,7 +294,10 @@ static inline bool early_radix_enabled(void)
>  #define MMU_PAGE_16G	14
>  #define MMU_PAGE_64G	15
>  
> -/* N.B. we need to change the type of hpte_page_sizes if this gets to be > 16 */
> +/*
> + * N.B. we need to change the type of hpte_page_sizes if this gets to be > 16
> + * Also we need to change he type of mm_context.low/high_slices_psize.
> + */
>  #define MMU_PAGE_COUNT	16
>  
>  #ifdef CONFIG_PPC_BOOK3S_64
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
> index d6041101a5e2..bed699ab7654 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_host.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
> @@ -229,6 +229,7 @@ void kvmppc_mmu_unmap_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
>  
>  static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
>  {
> +	unsigned long vsid_bits = VSID_BITS_65_256M;
>  	struct kvmppc_sid_map *map;
>  	struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
>  	u16 sid_map_mask;
> @@ -257,7 +258,12 @@ static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
>  		kvmppc_mmu_pte_flush(vcpu, 0, 0);
>  		kvmppc_mmu_flush_segments(vcpu);
>  	}
> -	map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++, 256M);
> +
> +	if (mmu_has_feature(MMU_FTR_68_BIT_VA))
> +		vsid_bits = VSID_BITS_256M;
> +
> +	map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++,
> +				       VSID_MULTIPLIER_256M, vsid_bits);
>  
>  	map->guest_vsid = gvsid;
>  	map->valid = true;
> diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
> index a6450c7f9cf3..e6a5bcbf8abe 100644
> --- a/arch/powerpc/mm/mmu_context_book3s64.c
> +++ b/arch/powerpc/mm/mmu_context_book3s64.c
> @@ -33,6 +33,12 @@ static DEFINE_IDA(mmu_context_ida);
>  int hash__get_new_context(void)
>  {
>  	int index, err;
> +	unsigned long max_user_context;
> +
> +	if (mmu_has_feature(MMU_FTR_68_BIT_VA))
> +		max_user_context = MAX_USER_CONTEXT;
> +	else
> +		max_user_context = MAX_USER_CONTEXT_65BIT_VA;
>  
>  again:
>  	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
> @@ -50,7 +56,7 @@ int hash__get_new_context(void)
>  	else if (err)
>  		return err;
>  
> -	if (index > MAX_USER_CONTEXT) {
> +	if (index > max_user_context) {
>  		spin_lock(&mmu_context_lock);
>  		ida_remove(&mmu_context_ida, index);
>  		spin_unlock(&mmu_context_lock);
> diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
> index 4ce050ea4200..bb75a667483e 100644
> --- a/arch/powerpc/mm/slb_low.S
> +++ b/arch/powerpc/mm/slb_low.S
> @@ -23,6 +23,48 @@
>  #include <asm/pgtable.h>
>  #include <asm/firmware.h>
>  
> +/*
> + * This macro generates asm code to compute the VSID scramble
> + * function.  Used in slb_allocate() and do_stab_bolted.  The function
> + * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
> + *
> + *	rt = register containing the proto-VSID and into which the
> + *		VSID will be stored
> + *	rx = scratch register (clobbered)
> + *	rf = flags
> + *
> + *	- rt and rx must be different registers
> + *	- The answer will end up in the low VSID_BITS bits of rt.  The higher
> + *	  bits may contain other garbage, so you may need to mask the
> + *	  result.
> + */
> +#define ASM_VSID_SCRAMBLE(rt, rx, rf, size)				\
> +	lis	rx,VSID_MULTIPLIER_##size@h;				\
> +	ori	rx,rx,VSID_MULTIPLIER_##size@l;				\
> +	mulld	rt,rt,rx;		/* rt = rt * MULTIPLIER */	\
> +/*									\
> + * powermac get slb fault before feature fixup, so make 65 bit part     \
> + * the default part of feature fixup					\
> + */									\
> +BEGIN_MMU_FTR_SECTION							\
> +	srdi	rx,rt,VSID_BITS_65_##size;				\
> +	clrldi	rt,rt,(64-VSID_BITS_65_##size);				\
> +	add	rt,rt,rx;						\
> +	addi	rx,rt,1;						\
> +	srdi	rx,rx,VSID_BITS_65_##size;				\
> +	add	rt,rt,rx;						\
> +	rldimi	rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_65_##size)); \
> +MMU_FTR_SECTION_ELSE							\
> +	srdi	rx,rt,VSID_BITS_##size;					\
> +	clrldi	rt,rt,(64-VSID_BITS_##size);				\
> +	add	rt,rt,rx;		/* add high and low bits */	\
> +	addi	rx,rt,1;						\
> +	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
> +	add	rt,rt,rx;						\
> +	rldimi	rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_##size)); \

Don't like this bit, it does more than scramble, it adds the flags to the generated
scramble bits, could we please revisit what ASM_VSID_SCRAMBLE should do?

Otherwise,

Acked-by: Balbir Singh <bsingharora@gmail.com>

Balbir

[PATCH V3 05/10] powerpc/mm: Move copy_mm_to_paca to paca.c

[Aneesh Kumar K.V]

We will be updating this later to use struct mm_struct. Move this so that function
finds the definition of struct mm_struct;

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/paca.h | 18 +-----------------
 arch/powerpc/kernel/paca.c      | 19 +++++++++++++++++++
 arch/powerpc/mm/hash_utils_64.c |  4 ++--
 arch/powerpc/mm/slb.c           |  2 +-
 arch/powerpc/mm/slice.c         |  2 +-
 5 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 6a6792bb39fb..f25d3c93a30f 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -207,23 +207,7 @@ struct paca_struct {
 #endif
 };
 
-#ifdef CONFIG_PPC_BOOK3S
-static inline void copy_mm_to_paca(mm_context_t *context)
-{
-	get_paca()->mm_ctx_id = context->id;
-#ifdef CONFIG_PPC_MM_SLICES
-	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
-	memcpy(&get_paca()->mm_ctx_high_slices_psize,
-	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
-#else
-	get_paca()->mm_ctx_user_psize = context->user_psize;
-	get_paca()->mm_ctx_sllp = context->sllp;
-#endif
-}
-#else
-static inline void copy_mm_to_paca(mm_context_t *context){}
-#endif
-
+extern void copy_mm_to_paca(struct mm_struct *mm);
 extern struct paca_struct *paca;
 extern void initialise_paca(struct paca_struct *new_paca, int cpu);
 extern void setup_paca(struct paca_struct *new_paca);
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index fa20060ff7a5..b64daf124fee 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -244,3 +244,22 @@ void __init free_unused_pacas(void)
 
 	free_lppacas();
 }
+
+void copy_mm_to_paca(struct mm_struct *mm)
+{
+#ifdef CONFIG_PPC_BOOK3S
+	mm_context_t *context = &mm->context;
+
+	get_paca()->mm_ctx_id = context->id;
+#ifdef CONFIG_PPC_MM_SLICES
+	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
+	memcpy(&get_paca()->mm_ctx_high_slices_psize,
+	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
+#else /* CONFIG_PPC_MM_SLICES */
+	get_paca()->mm_ctx_user_psize = context->user_psize;
+	get_paca()->mm_ctx_sllp = context->sllp;
+#endif
+#else /* CONFIG_PPC_BOOK3S */
+	return;
+#endif
+}
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 978314b6b8d7..67937a6eb541 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1084,7 +1084,7 @@ void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
 	copro_flush_all_slbs(mm);
 	if ((get_paca_psize(addr) != MMU_PAGE_4K) && (current->mm == mm)) {
 
-		copy_mm_to_paca(&mm->context);
+		copy_mm_to_paca(mm);
 		slb_flush_and_rebolt();
 	}
 }
@@ -1156,7 +1156,7 @@ static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
 {
 	if (user_region) {
 		if (psize != get_paca_psize(ea)) {
-			copy_mm_to_paca(&mm->context);
+			copy_mm_to_paca(mm);
 			slb_flush_and_rebolt();
 		}
 	} else if (get_paca()->vmalloc_sllp !=
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index 48fc28bab544..15157b14b0b6 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -227,7 +227,7 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
 		asm volatile("slbie %0" : : "r" (slbie_data));
 
 	get_paca()->slb_cache_ptr = 0;
-	copy_mm_to_paca(&mm->context);
+	copy_mm_to_paca(mm);
 
 	/*
 	 * preload some userspace segments into the SLB.
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 1cb0e98e70c0..da67b91f46d3 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -193,7 +193,7 @@ static void slice_flush_segments(void *parm)
 	if (mm != current->active_mm)
 		return;
 
-	copy_mm_to_paca(&current->active_mm->context);
+	copy_mm_to_paca(current->active_mm);
 
 	local_irq_save(flags);
 	slb_flush_and_rebolt();
-- 
2.7.4

[PATCH V3 06/10] powerpc/mm: Remove redundant TASK_SIZE_USER64 checks

[Aneesh Kumar K.V]

The check against VSID range is implied when we check task size against
hash and radix pgtable range[1], because we make sure page table range cannot
exceed vsid range.

[1] BUILD_BUG_ON(TASK_SIZE_USER64 > H_PGTABLE_RANGE);
BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);

The check for smaller task size is also removed here, because the follow up
patch will support a tasksize smaller than pgtable range.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/init_64.c    | 4 ----
 arch/powerpc/mm/pgtable_64.c | 5 -----
 2 files changed, 9 deletions(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 93abf8a9813d..f3e856e6ee23 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -69,10 +69,6 @@
 #if H_PGTABLE_RANGE > USER_VSID_RANGE
 #warning Limited user VSID range means pagetable space is wasted
 #endif
-
-#if (TASK_SIZE_USER64 < H_PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
-#warning TASK_SIZE is smaller than it needs to be.
-#endif
 #endif /* CONFIG_PPC_STD_MMU_64 */
 
 phys_addr_t memstart_addr = ~0;
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 8bca7f58afc4..06e23e0b1b81 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -55,11 +55,6 @@
 
 #include "mmu_decl.h"
 
-#ifdef CONFIG_PPC_STD_MMU_64
-#if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT))
-#error TASK_SIZE_USER64 exceeds user VSID range
-#endif
-#endif
 
 #ifdef CONFIG_PPC_BOOK3S_64
 /*
-- 
2.7.4

Re: [PATCH V3 06/10] powerpc/mm: Remove redundant TASK_SIZE_USER64 checks

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:13PM +0530, Aneesh Kumar K.V wrote:
> The check against VSID range is implied when we check task size against
> hash and radix pgtable range[1], because we make sure page table range cannot
> exceed vsid range.
> 
> [1] BUILD_BUG_ON(TASK_SIZE_USER64 > H_PGTABLE_RANGE);
> BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);
> 
> The check for smaller task size is also removed here, because the follow up
> patch will support a tasksize smaller than pgtable range.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---

Acked-by: Balbir Singh <bsingharora@gmail.com>

[PATCH V3 07/10] powerpc/mm/slice: Use mm task_size as max value of slice index

[Aneesh Kumar K.V]

In the followup patch, we will increase the slice array sice to handle 512TB
range, but will limit the task size to 128TB. Avoid doing uncessary computation
and avoid doing slice mask related operation above task_size.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/slice.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index da67b91f46d3..f286b7839a12 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -145,7 +145,7 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret)
 	if (mm->task_size <= SLICE_LOW_TOP)
 		return;
 
-	for (i = 0; i < SLICE_NUM_HIGH; i++)
+	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->task_size); i++)
 		if (!slice_high_has_vma(mm, i))
 			__set_bit(i, ret->high_slices);
 }
@@ -166,7 +166,7 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
 			ret->low_slices |= 1u << i;
 
 	hpsizes = mm->context.high_slices_psize;
-	for (i = 0; i < SLICE_NUM_HIGH; i++) {
+	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->task_size); i++) {
 		mask_index = i & 0x1;
 		index = i >> 1;
 		if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
@@ -174,15 +174,17 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
 	}
 }
 
-static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
+static int slice_check_fit(struct mm_struct *mm,
+			   struct slice_mask mask, struct slice_mask available)
 {
 	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
+	unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->task_size);
 
 	bitmap_and(result, mask.high_slices,
-		   available.high_slices, SLICE_NUM_HIGH);
+		   available.high_slices, slice_count);
 
 	return (mask.low_slices & available.low_slices) == mask.low_slices &&
-		bitmap_equal(result, mask.high_slices, SLICE_NUM_HIGH);
+		bitmap_equal(result, mask.high_slices, slice_count);
 }
 
 static void slice_flush_segments(void *parm)
@@ -226,7 +228,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
 	mm->context.low_slices_psize = lpsizes;
 
 	hpsizes = mm->context.high_slices_psize;
-	for (i = 0; i < SLICE_NUM_HIGH; i++) {
+	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->task_size); i++) {
 		mask_index = i & 0x1;
 		index = i >> 1;
 		if (test_bit(i, mask.high_slices))
@@ -493,7 +495,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 		/* Check if we fit in the good mask. If we do, we just return,
 		 * nothing else to do
 		 */
-		if (slice_check_fit(mask, good_mask)) {
+		if (slice_check_fit(mm, mask, good_mask)) {
 			slice_dbg(" fits good !\n");
 			return addr;
 		}
@@ -518,7 +520,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	slice_or_mask(&potential_mask, &good_mask);
 	slice_print_mask(" potential", potential_mask);
 
-	if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
+	if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
 		slice_dbg(" fits potential !\n");
 		goto convert;
 	}
@@ -666,7 +668,7 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 	mm->context.low_slices_psize = lpsizes;
 
 	hpsizes = mm->context.high_slices_psize;
-	for (i = 0; i < SLICE_NUM_HIGH; i++) {
+	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->task_size); i++) {
 		mask_index = i & 0x1;
 		index = i >> 1;
 		if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == old_psize)
@@ -743,6 +745,6 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 	slice_print_mask(" mask", mask);
 	slice_print_mask(" available", available);
 #endif
-	return !slice_check_fit(mask, available);
+	return !slice_check_fit(mm, mask, available);
 }
 #endif
-- 
2.7.4

[PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB

[Aneesh Kumar K.V]

We update the hash linux page table layout such that we can support 512TB. But
we limit the TASK_SIZE to 128TB. We can switch to 128TB by default without
conditional because that is the max virtual address supported by other
architectures. We will later add a mechanism to on-demand increase the
application's effective address range to 512TB.

Having the page table layout changed to accommodate 512TB  makes testing large
memory configuration easier with less code changes to kernel

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
 arch/powerpc/include/asm/page_64.h            |  2 +-
 arch/powerpc/include/asm/processor.h          | 22 ++++++++++++++++++----
 arch/powerpc/kernel/paca.c                    |  9 ++++++++-
 arch/powerpc/mm/slice.c                       |  2 ++
 6 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index 0c4e470571ca..b4b5e6b671ca 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -8,7 +8,7 @@
 #define H_PTE_INDEX_SIZE  9
 #define H_PMD_INDEX_SIZE  7
 #define H_PUD_INDEX_SIZE  9
-#define H_PGD_INDEX_SIZE  9
+#define H_PGD_INDEX_SIZE  12
 
 #ifndef __ASSEMBLY__
 #define H_PTE_TABLE_SIZE	(sizeof(pte_t) << H_PTE_INDEX_SIZE)
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index b39f0b86405e..682c4eb28fa4 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -4,7 +4,7 @@
 #define H_PTE_INDEX_SIZE  8
 #define H_PMD_INDEX_SIZE  5
 #define H_PUD_INDEX_SIZE  5
-#define H_PGD_INDEX_SIZE  12
+#define H_PGD_INDEX_SIZE  15
 
 /*
  * 64k aligned address free up few of the lower bits of RPN for us
diff --git a/arch/powerpc/include/asm/page_64.h b/arch/powerpc/include/asm/page_64.h
index 7f72659b7999..9b60e9455c6e 100644
--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h
@@ -107,7 +107,7 @@ extern u64 ppc64_pft_size;
  */
 struct slice_mask {
 	u16 low_slices;
-	DECLARE_BITMAP(high_slices, 64);
+	DECLARE_BITMAP(high_slices, 512);
 };
 
 struct mm_struct;
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 1ba814436c73..1d4e34f9004d 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -102,11 +102,25 @@ void release_thread(struct task_struct *);
 #endif
 
 #ifdef CONFIG_PPC64
-/* 64-bit user address space is 46-bits (64TB user VM) */
-#define TASK_SIZE_USER64 (0x0000400000000000UL)
+/*
+ * 64-bit user address space can have multiple limits
+ * For now supported values are:
+ */
+#define TASK_SIZE_64TB  (0x0000400000000000UL)
+#define TASK_SIZE_128TB (0x0000800000000000UL)
+#define TASK_SIZE_512TB (0x0002000000000000UL)
 
-/* 
- * 32-bit user address space is 4GB - 1 page 
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * MAx value currently used:
+ */
+#define TASK_SIZE_USER64 TASK_SIZE_128TB
+#else
+#define TASK_SIZE_USER64 TASK_SIZE_64TB
+#endif
+
+/*
+ * 32-bit user address space is 4GB - 1 page
  * (this 1 page is needed so referencing of 0xFFFFFFFF generates EFAULT
  */
 #define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE))
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index b64daf124fee..c7ca70dc3ba5 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
 	get_paca()->mm_ctx_id = context->id;
 #ifdef CONFIG_PPC_MM_SLICES
 	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
+	/*
+	 * We support upto 128TB for now. Hence copy only 128/2 bytes.
+	 * Later when we support tasks with different max effective
+	 * address, we can optimize this based on mm->task_size.
+	 */
+	BUILD_BUG_ON(TASK_SIZE_USER64 != TASK_SIZE_128TB);
 	memcpy(&get_paca()->mm_ctx_high_slices_psize,
-	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
+	       &context->high_slices_psize, TASK_SIZE_128TB >> 41);
+
 #else /* CONFIG_PPC_MM_SLICES */
 	get_paca()->mm_ctx_user_psize = context->user_psize;
 	get_paca()->mm_ctx_sllp = context->sllp;
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index f286b7839a12..fd2c85e951bd 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -412,6 +412,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	struct mm_struct *mm = current->mm;
 	unsigned long newaddr;
 
+	/* Make sure high_slices bitmap size is same as we expected */
+	BUILD_BUG_ON(512 != SLICE_NUM_HIGH);
 	/*
 	 * init different masks
 	 */
-- 
2.7.4

Re: [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB

[Michal Suchánek]

Hello,

On Sun, 19 Feb 2017 15:37:15 +0530
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:

> We update the hash linux page table layout such that we can support
> 512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
> default without conditional because that is the max virtual address
> supported by other architectures. We will later add a mechanism to
> on-demand increase the application's effective address range to 512TB.
> 
> Having the page table layout changed to accommodate 512TB  makes
> testing large memory configuration easier with less code changes to
> kernel
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
>  arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
>  arch/powerpc/include/asm/page_64.h            |  2 +-
>  arch/powerpc/include/asm/processor.h          | 22
> ++++++++++++++++++---- arch/powerpc/kernel/paca.c
> |  9 ++++++++- arch/powerpc/mm/slice.c                       |  2 ++
>  6 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h
> b/arch/powerpc/include/asm/book3s/64/hash-4k.h index
> 0c4e470571ca..b4b5e6b671ca 100644 ---
> a/arch/powerpc/include/asm/book3s/64/hash-4k.h +++
> b/arch/powerpc/include/asm/book3s/64/hash-4k.h @@ -8,7 +8,7 @@
>  #define H_PTE_INDEX_SIZE  9
>  #define H_PMD_INDEX_SIZE  7
>  #define H_PUD_INDEX_SIZE  9
> -#define H_PGD_INDEX_SIZE  9
> +#define H_PGD_INDEX_SIZE  12
>  
>  #ifndef __ASSEMBLY__
>  #define H_PTE_TABLE_SIZE	(sizeof(pte_t) << H_PTE_INDEX_SIZE)
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h
> b/arch/powerpc/include/asm/book3s/64/hash-64k.h index
> b39f0b86405e..682c4eb28fa4 100644 ---
> a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++
> b/arch/powerpc/include/asm/book3s/64/hash-64k.h @@ -4,7 +4,7 @@
>  #define H_PTE_INDEX_SIZE  8
>  #define H_PMD_INDEX_SIZE  5
>  #define H_PUD_INDEX_SIZE  5
> -#define H_PGD_INDEX_SIZE  12
> +#define H_PGD_INDEX_SIZE  15
>  
>  /*
>   * 64k aligned address free up few of the lower bits of RPN for us
> diff --git a/arch/powerpc/include/asm/page_64.h
> b/arch/powerpc/include/asm/page_64.h index 7f72659b7999..9b60e9455c6e
> 100644 --- a/arch/powerpc/include/asm/page_64.h
> +++ b/arch/powerpc/include/asm/page_64.h
> @@ -107,7 +107,7 @@ extern u64 ppc64_pft_size;
>   */
>  struct slice_mask {
>  	u16 low_slices;
> -	DECLARE_BITMAP(high_slices, 64);
> +	DECLARE_BITMAP(high_slices, 512);
>  };
>  
>  struct mm_struct;
> diff --git a/arch/powerpc/include/asm/processor.h
> b/arch/powerpc/include/asm/processor.h index
> 1ba814436c73..1d4e34f9004d 100644 ---
> a/arch/powerpc/include/asm/processor.h +++
> b/arch/powerpc/include/asm/processor.h @@ -102,11 +102,25 @@ void
> release_thread(struct task_struct *); #endif
>  
>  #ifdef CONFIG_PPC64
> -/* 64-bit user address space is 46-bits (64TB user VM) */
> -#define TASK_SIZE_USER64 (0x0000400000000000UL)
> +/*
> + * 64-bit user address space can have multiple limits
> + * For now supported values are:
> + */
> +#define TASK_SIZE_64TB  (0x0000400000000000UL)
> +#define TASK_SIZE_128TB (0x0000800000000000UL)
> +#define TASK_SIZE_512TB (0x0002000000000000UL)
>  
> -/* 
> - * 32-bit user address space is 4GB - 1 page 
> +#ifdef CONFIG_PPC_BOOK3S_64
> +/*
> + * MAx value currently used:
> + */
> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
> +#else
> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
> +#endif
> +
> +/*
> + * 32-bit user address space is 4GB - 1 page
>   * (this 1 page is needed so referencing of 0xFFFFFFFF generates
> EFAULT */
>  #define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE))
> diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
> index b64daf124fee..c7ca70dc3ba5 100644
> --- a/arch/powerpc/kernel/paca.c
> +++ b/arch/powerpc/kernel/paca.c
> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
>  	get_paca()->mm_ctx_id = context->id;
>  #ifdef CONFIG_PPC_MM_SLICES
>  	get_paca()->mm_ctx_low_slices_psize =
> context->low_slices_psize;
> +	/*
> +	 * We support upto 128TB for now. Hence copy only 128/2
> bytes.
> +	 * Later when we support tasks with different max effective
> +	 * address, we can optimize this based on mm->task_size.
> +	 */
> +	BUILD_BUG_ON(TASK_SIZE_USER64 != TASK_SIZE_128TB);

Can this be handled by KConfig?
Above I see 
> +#ifdef CONFIG_PPC_BOOK3S_64
> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
> +#else
> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
> +#endif
and 
> #ifdef CONFIG_PPC_MM_SLICES
> ILD_BUG_ON(TASK_SIZE_USER64 != TASK_SIZE_128TB)

which boils down to
#ifndef CONFIG_PPC_BOOK3S_64
#ifdef CONFIG_PPC_MM_SLICES
#error TASK_SIZE_USER64 != TASK_SIZE_128TB


>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
> -	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
> +	       &context->high_slices_psize, TASK_SIZE_128TB >> 41);

Can we avoid magic numbers, please?

Thanks

Michal

> +
>  #else /* CONFIG_PPC_MM_SLICES */
>  	get_paca()->mm_ctx_user_psize = context->user_psize;
>  	get_paca()->mm_ctx_sllp = context->sllp;
> diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
> index f286b7839a12..fd2c85e951bd 100644
> --- a/arch/powerpc/mm/slice.c
> +++ b/arch/powerpc/mm/slice.c
> @@ -412,6 +412,8 @@ unsigned long slice_get_unmapped_area(unsigned
> long addr, unsigned long len, struct mm_struct *mm = current->mm;
>  	unsigned long newaddr;
>  
> +	/* Make sure high_slices bitmap size is same as we expected
> */
> +	BUILD_BUG_ON(512 != SLICE_NUM_HIGH);
>  	/*
>  	 * init different masks
>  	 */

Re: [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB

[Aneesh Kumar K.V]

Michal Such=C3=A1nek <msuchanek@suse.de> writes:

> Hello,
>
> On Sun, 19 Feb 2017 15:37:15 +0530
> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
>
>> We update the hash linux page table layout such that we can support
>> 512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
>> default without conditional because that is the max virtual address
>> supported by other architectures. We will later add a mechanism to
>> on-demand increase the application's effective address range to 512TB.
>>=20
>> Having the page table layout changed to accommodate 512TB  makes
>> testing large memory configuration easier with less code changes to
>> kernel
>>=20
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

....

> index b64daf124fee..c7ca70dc3ba5 100644
>> --- a/arch/powerpc/kernel/paca.c
>> +++ b/arch/powerpc/kernel/paca.c
>> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
>>  	get_paca()->mm_ctx_id =3D context->id;
>>  #ifdef CONFIG_PPC_MM_SLICES
>>  	get_paca()->mm_ctx_low_slices_psize =3D
>> context->low_slices_psize;
>> +	/*
>> +	 * We support upto 128TB for now. Hence copy only 128/2
>> bytes.
>> +	 * Later when we support tasks with different max effective
>> +	 * address, we can optimize this based on mm->task_size.
>> +	 */
>> +	BUILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB);
>
> Can this be handled by KConfig?
> Above I see=20

I am reworking the series so that we depend on mm->task_size. Will send
a new version soon.



>> +#ifdef CONFIG_PPC_BOOK3S_64
>> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
>> +#else
>> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
>> +#endif
> and=20
>> #ifdef CONFIG_PPC_MM_SLICES
>> ILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB)
>
> which boils down to
> #ifndef CONFIG_PPC_BOOK3S_64
> #ifdef CONFIG_PPC_MM_SLICES
> #error TASK_SIZE_USER64 !=3D TASK_SIZE_128TB
>
>
>>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
>> -	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
>> +	       &context->high_slices_psize, TASK_SIZE_128TB >> 41);
>
> Can we avoid magic numbers, please?
>

Since array is 4 bytes per each TB which is documented else where.
Considering we are just converting max range there, do we need that as a
macro ?

-aneesh

Re: [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB

[Aneesh Kumar K.V]

"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:

> Michal Such=C3=A1nek <msuchanek@suse.de> writes:
>
>> Hello,
>>
>> On Sun, 19 Feb 2017 15:37:15 +0530
>> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
>>
>>> We update the hash linux page table layout such that we can support
>>> 512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
>>> default without conditional because that is the max virtual address
>>> supported by other architectures. We will later add a mechanism to
>>> on-demand increase the application's effective address range to 512TB.
>>>=20
>>> Having the page table layout changed to accommodate 512TB  makes
>>> testing large memory configuration easier with less code changes to
>>> kernel
>>>=20
>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>
> ....
>
>> index b64daf124fee..c7ca70dc3ba5 100644
>>> --- a/arch/powerpc/kernel/paca.c
>>> +++ b/arch/powerpc/kernel/paca.c
>>> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
>>>  	get_paca()->mm_ctx_id =3D context->id;
>>>  #ifdef CONFIG_PPC_MM_SLICES
>>>  	get_paca()->mm_ctx_low_slices_psize =3D
>>> context->low_slices_psize;
>>> +	/*
>>> +	 * We support upto 128TB for now. Hence copy only 128/2
>>> bytes.
>>> +	 * Later when we support tasks with different max effective
>>> +	 * address, we can optimize this based on mm->task_size.
>>> +	 */
>>> +	BUILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB);
>>
>> Can this be handled by KConfig?
>> Above I see=20
>
> I am reworking the series so that we depend on mm->task_size. Will send
> a new version soon.
>
>
>
>>> +#ifdef CONFIG_PPC_BOOK3S_64
>>> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
>>> +#else
>>> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
>>> +#endif
>> and=20
>>> #ifdef CONFIG_PPC_MM_SLICES
>>> ILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB)
>>
>> which boils down to
>> #ifndef CONFIG_PPC_BOOK3S_64
>> #ifdef CONFIG_PPC_MM_SLICES
>> #error TASK_SIZE_USER64 !=3D TASK_SIZE_128TB
>>
>>
>>>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
>>> -	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
>>> +	       &context->high_slices_psize, TASK_SIZE_128TB >> 41);
>>
>> Can we avoid magic numbers, please?
>>
>
> Since array is 4 bytes per each TB which is documented else where.

4 bits per teach TB.


-aneesh

Re: [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB

[Michal Suchánek]

On Mon, 06 Mar 2017 09:07:48 +0530
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:

> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:
>=20
> > Michal Such=C3=A1nek <msuchanek@suse.de> writes:
> > =20
> >> Hello,
> >>
> >> On Sun, 19 Feb 2017 15:37:15 +0530
> >> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> >> =20
> >>> We update the hash linux page table layout such that we can
> >>> support 512TB. But we limit the TASK_SIZE to 128TB. We can switch
> >>> to 128TB by default without conditional because that is the max
> >>> virtual address supported by other architectures. We will later
> >>> add a mechanism to on-demand increase the application's effective
> >>> address range to 512TB.
> >>>=20
> >>> Having the page table layout changed to accommodate 512TB  makes
> >>> testing large memory configuration easier with less code changes
> >>> to kernel
> >>>=20
> >>> Signed-off-by: Aneesh Kumar K.V
> >>> <aneesh.kumar@linux.vnet.ibm.com> =20
> >
> > ....
> > =20
> >> index b64daf124fee..c7ca70dc3ba5 100644 =20
> >>> --- a/arch/powerpc/kernel/paca.c
> >>> +++ b/arch/powerpc/kernel/paca.c
> >>> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
> >>>  	get_paca()->mm_ctx_id =3D context->id;
> >>>  #ifdef CONFIG_PPC_MM_SLICES
> >>>  	get_paca()->mm_ctx_low_slices_psize =3D
> >>> context->low_slices_psize;
> >>> +	/*
> >>> +	 * We support upto 128TB for now. Hence copy only 128/2
> >>> bytes.
> >>> +	 * Later when we support tasks with different max
> >>> effective
> >>> +	 * address, we can optimize this based on mm->task_size.
> >>> +	 */
> >>> +	BUILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB); =20
> >>
> >> Can this be handled by KConfig?
> >> Above I see  =20
> >
> > I am reworking the series so that we depend on mm->task_size. Will
> > send a new version soon.
> >
> >
> > =20
> >>> +#ifdef CONFIG_PPC_BOOK3S_64
> >>> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
> >>> +#else
> >>> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
> >>> +#endif =20
> >> and  =20
> >>> #ifdef CONFIG_PPC_MM_SLICES
> >>> ILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB) =20
> >>
> >> which boils down to
> >> #ifndef CONFIG_PPC_BOOK3S_64
> >> #ifdef CONFIG_PPC_MM_SLICES
> >> #error TASK_SIZE_USER64 !=3D TASK_SIZE_128TB
> >>
> >> =20
> >>>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
> >>> -	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
> >>> +	       &context->high_slices_psize, TASK_SIZE_128TB >>
> >>> 41); =20
> >>
> >> Can we avoid magic numbers, please?
> >> =20
> >
> > Since array is 4 bytes per each TB which is documented else where. =20
>=20
> 4 bits per teach TB.
>=20
It is certainly nicer to have a macro for it. You can then see what the
number is from the macro name or grep it and find the definition and
the explanation.

Thanks

Michal

[PATCH V3 09/10] powerpc/mm/slice: Move slice_mask struct definition to slice.c

[Aneesh Kumar K.V]

This structure definition need not be in a header since this is used only by
slice.c file. So move it to slice.c. This also allow us to use SLICE_NUM_HIGH
instead of 512 and also helps in getting rid of one BUILD_BUG_ON().

I also switch the low_slices type to u64 from u16. This doesn't have an impact
on size of struct due to padding added with u16 type. This helps in using
bitmap printing function for printing slice mask.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/page_64.h | 11 -----------
 arch/powerpc/mm/slice.c            | 13 ++++++++++---
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/page_64.h b/arch/powerpc/include/asm/page_64.h
index 9b60e9455c6e..3ecfc2734b50 100644
--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h
@@ -99,17 +99,6 @@ extern u64 ppc64_pft_size;
 #define GET_HIGH_SLICE_INDEX(addr)	((addr) >> SLICE_HIGH_SHIFT)
 
 #ifndef __ASSEMBLY__
-/*
- * One bit per slice. We have lower slices which cover 256MB segments
- * upto 4G range. That gets us 16 low slices. For the rest we track slices
- * in 1TB size.
- * 64 below is actually SLICE_NUM_HIGH to fixup complie errros
- */
-struct slice_mask {
-	u16 low_slices;
-	DECLARE_BITMAP(high_slices, 512);
-};
-
 struct mm_struct;
 
 extern unsigned long slice_get_unmapped_area(unsigned long addr,
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index fd2c85e951bd..8eedb7382942 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -37,7 +37,16 @@
 #include <asm/hugetlb.h>
 
 static DEFINE_SPINLOCK(slice_convert_lock);
-
+/*
+ * One bit per slice. We have lower slices which cover 256MB segments
+ * upto 4G range. That gets us 16 low slices. For the rest we track slices
+ * in 1TB size.
+ * 64 below is actually SLICE_NUM_HIGH to fixup complie errros
+ */
+struct slice_mask {
+	u64 low_slices;
+	DECLARE_BITMAP(high_slices, SLICE_NUM_HIGH);
+};
 
 #ifdef DEBUG
 int _slice_debug = 1;
@@ -412,8 +421,6 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	struct mm_struct *mm = current->mm;
 	unsigned long newaddr;
 
-	/* Make sure high_slices bitmap size is same as we expected */
-	BUILD_BUG_ON(512 != SLICE_NUM_HIGH);
 	/*
 	 * init different masks
 	 */
-- 
2.7.4

Re: [PATCH V3 09/10] powerpc/mm/slice: Move slice_mask struct definition to slice.c

[Michal Suchánek]

Hello,

On Sun, 19 Feb 2017 15:37:16 +0530
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:

> This structure definition need not be in a header since this is used
> only by slice.c file. So move it to slice.c. This also allow us to
> use SLICE_NUM_HIGH instead of 512 and also helps in getting rid of
> one BUILD_BUG_ON().
> 
> I also switch the low_slices type to u64 from u16. This doesn't have
> an impact on size of struct due to padding added with u16 type. This
> helps in using bitmap printing function for printing slice mask.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/page_64.h | 11 -----------
>  arch/powerpc/mm/slice.c            | 13 ++++++++++---
>  2 files changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/page_64.h
> b/arch/powerpc/include/asm/page_64.h index 9b60e9455c6e..3ecfc2734b50
> 100644 --- a/arch/powerpc/include/asm/page_64.h
> +++ b/arch/powerpc/include/asm/page_64.h
> @@ -99,17 +99,6 @@ extern u64 ppc64_pft_size;
>  #define GET_HIGH_SLICE_INDEX(addr)	((addr) >>
> SLICE_HIGH_SHIFT) 
>  #ifndef __ASSEMBLY__
> -/*
> - * One bit per slice. We have lower slices which cover 256MB segments
> - * upto 4G range. That gets us 16 low slices. For the rest we track
> slices
> - * in 1TB size.
> - * 64 below is actually SLICE_NUM_HIGH to fixup complie errros
> - */
> -struct slice_mask {
> -	u16 low_slices;
> -	DECLARE_BITMAP(high_slices, 512);
> -};
> -
>  struct mm_struct;
>  
>  extern unsigned long slice_get_unmapped_area(unsigned long addr,
> diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
> index fd2c85e951bd..8eedb7382942 100644
> --- a/arch/powerpc/mm/slice.c
> +++ b/arch/powerpc/mm/slice.c
> @@ -37,7 +37,16 @@
>  #include <asm/hugetlb.h>
>  
>  static DEFINE_SPINLOCK(slice_convert_lock);
> -
> +/*
> + * One bit per slice. We have lower slices which cover 256MB segments
> + * upto 4G range. That gets us 16 low slices. For the rest we track
> slices
> + * in 1TB size.
> + * 64 below is actually SLICE_NUM_HIGH to fixup complie errros*
Please remove the above line which no longer applies for multiple
reasons.

Also consider swapping this and the previous patch.

Thanks

Michal
> + */
> +struct slice_mask {
> +	u64 low_slices;
> +	DECLARE_BITMAP(high_slices, SLICE_NUM_HIGH);
> +};
>  
>  #ifdef DEBUG
>  int _slice_debug = 1;
> @@ -412,8 +421,6 @@ unsigned long slice_get_unmapped_area(unsigned
> long addr, unsigned long len, struct mm_struct *mm = current->mm;
>  	unsigned long newaddr;
>  
> -	/* Make sure high_slices bitmap size is same as we expected
> */
> -	BUILD_BUG_ON(512 != SLICE_NUM_HIGH);
>  	/*
>  	 * init different masks
>  	 */

[PATCH V3 10/10] powerpc/mm/slice: Update slice mask printing to use bitmap printing.

[Aneesh Kumar K.V]

We now get output like below which is much better.

[    0.935306]  good_mask low_slice: 0-15
[    0.935360]  good_mask high_slice: 0-511

Compared to

[    0.953414]  good_mask:1111111111111111 - 1111111111111.........

I also fixed an error with slice_dbg printing.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/slice.c | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 8eedb7382942..fce1734ab8a3 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -53,29 +53,13 @@ int _slice_debug = 1;
 
 static void slice_print_mask(const char *label, struct slice_mask mask)
 {
-	char	*p, buf[SLICE_NUM_LOW + 3 + SLICE_NUM_HIGH + 1];
-	int	i;
-
 	if (!_slice_debug)
 		return;
-	p = buf;
-	for (i = 0; i < SLICE_NUM_LOW; i++)
-		*(p++) = (mask.low_slices & (1 << i)) ? '1' : '0';
-	*(p++) = ' ';
-	*(p++) = '-';
-	*(p++) = ' ';
-	for (i = 0; i < SLICE_NUM_HIGH; i++) {
-		if (test_bit(i, mask.high_slices))
-			*(p++) = '1';
-		else
-			*(p++) = '0';
-	}
-	*(p++) = 0;
-
-	printk(KERN_DEBUG "%s:%s\n", label, buf);
+	pr_devel("%s low_slice: %*pbl\n", label, (int)SLICE_NUM_LOW, &mask.low_slices);
+	pr_devel("%s high_slice: %*pbl\n", label, (int)SLICE_NUM_HIGH, mask.high_slices);
 }
 
-#define slice_dbg(fmt...) do { if (_slice_debug) pr_debug(fmt); } while(0)
+#define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
 
 #else
 
@@ -247,8 +231,8 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
 	}
 
 	slice_dbg(" lsps=%lx, hsps=%lx\n",
-		  mm->context.low_slices_psize,
-		  mm->context.high_slices_psize);
+		  (unsigned long)mm->context.low_slices_psize,
+		  (unsigned long)mm->context.high_slices_psize);
 
 	spin_unlock_irqrestore(&slice_convert_lock, flags);
 
@@ -690,8 +674,8 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 
 
 	slice_dbg(" lsps=%lx, hsps=%lx\n",
-		  mm->context.low_slices_psize,
-		  mm->context.high_slices_psize);
+		  (unsigned long)mm->context.low_slices_psize,
+		  (unsigned long)mm->context.high_slices_psize);
 
  bail:
 	spin_unlock_irqrestore(&slice_convert_lock, flags);
-- 
2.7.4

Re: [PATCH V3 10/10] powerpc/mm/slice: Update slice mask printing to use bitmap printing.

[Balbir Singh]

On Sun, Feb 19, 2017 at 03:37:17PM +0530, Aneesh Kumar K.V wrote:
> We now get output like below which is much better.
> 
> [    0.935306]  good_mask low_slice: 0-15
> [    0.935360]  good_mask high_slice: 0-511
> 
> Compared to
> 
> [    0.953414]  good_mask:1111111111111111 - 1111111111111.........
> 
> I also fixed an error with slice_dbg printing.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---

Yep, like this much better

Acked-by: Balbir Singh <bsingharora@gmail.com>