[PATCH -V9 00/20] THP support for PPC64

[PATCH -V9 00/20] THP support for PPC64

[Aneesh Kumar K.V]

Hi,

This is the second patchset needed to support THP on ppc64. Some of the changes
included in this series are tricky in that it changes the powerpc linux page table
walk subtly. We also overload few of the pte flags for ptes at PMD level (huge
page PTEs).

mm/ changes are already merged to Andrew's -mm tree. I am including them in this series
for easy testing and review.

Some numbers:

The latency measurements code from Anton  found at
http://ozlabs.org/~anton/junkcode/latency2001.c

64K page size (With THP support)
--------------------------
[root@llmp24l02 test]# ./latency2001 8G
 8589934592    428.49 cycles    120.50 ns
[root@llmp24l02 test]# ./latency2001 -l 8G
 8589934592    471.16 cycles    132.50 ns
[root@llmp24l02 test]# echo never > /sys/kernel/mm/transparent_hugepage/enabled 
[root@llmp24l02 test]# ./latency2001 8G
 8589934592    766.52 cycles    215.56 ns
[root@llmp24l02 test]# 

4K page size (No THP support for 4K)
----------------------------
[root@llmp24l02 test]# ./latency2001 8G
 8589934592    814.88 cycles    229.16 ns
[root@llmp24l02 test]# ./latency2001 -l 8G
 8589934592    463.69 cycles    130.40 ns
[root@llmp24l02 test]# 

We are close to hugetlbfs in latency and we can achieve this with zero
config/page reservation. Most of the allocations above are fault allocated.

Another test that does 50000000 random access over 1GB area goes from
2.65 seconds to 1.07 seconds with this patchset.

split_huge_page impact:
---------------------
To look at the performance impact of large page invalidate, I tried the below
experiment. The test involved, accessing a large contiguous region of memory
location as below

    for (i = 0; i < size; i += PAGE_SIZE)
	data[i] = i;

We wanted to access the data in sequential order so that we look at the
worst case THP performance. Accesing the data in sequential order implies
we have the Page table cached and overhead of TLB miss is as minimal as
possible. We also don't touch the entire page, because that can result in
cache evict.

After we touched the full range as above, we now call mprotect on each
of that page. A mprotect will result in a hugepage split. This should
allow us to measure the impact of hugepage split.

    for (i = 0; i < size; i += PAGE_SIZE)
	 mprotect(&data[i], PAGE_SIZE, PROT_READ);

Split hugepage impact: 
---------------------
THP enabled: 2.851561705 seconds for test completion
THP disable: 3.599146098 seconds for test completion

We are 20.7% better than non THP case even when we have all the large pages split.

Detailed output:

THP enabled:
---------------------------------------
[root@llmp24l02 ~]# cat /proc/vmstat  | grep thp
thp_fault_alloc 0
thp_fault_fallback 0
thp_collapse_alloc 0
thp_collapse_alloc_failed 0
thp_split 0
thp_zero_page_alloc 0
thp_zero_page_alloc_failed 0
[root@llmp24l02 ~]# /root/thp/tools/perf/perf stat -e page-faults,dTLB-load-misses ./split-huge-page-mpro 20G                                                                      
time taken to touch all the data in ns: 2763096913 

 Performance counter stats for './split-huge-page-mpro 20G':

	     1,581 page-faults                                                 
	     3,159 dTLB-load-misses                                            

       2.851561705 seconds time elapsed

[root@llmp24l02 ~]# 
[root@llmp24l02 ~]# cat /proc/vmstat  | grep thp
thp_fault_alloc 1279
thp_fault_fallback 0
thp_collapse_alloc 0
thp_collapse_alloc_failed 0
thp_split 1279
thp_zero_page_alloc 0
thp_zero_page_alloc_failed 0
[root@llmp24l02 ~]# 

    77.05%  split-huge-page  [kernel.kallsyms]     [k] .clear_user_page                        
     7.10%  split-huge-page  [kernel.kallsyms]     [k] .perf_event_mmap_ctx                    
     1.51%  split-huge-page  split-huge-page-mpro  [.] 0x0000000000000a70                      
     0.96%  split-huge-page  [unknown]             [H] 0x000000000157e3bc                      
     0.81%  split-huge-page  [kernel.kallsyms]     [k] .up_write                               
     0.76%  split-huge-page  [kernel.kallsyms]     [k] .perf_event_mmap                        
     0.76%  split-huge-page  [kernel.kallsyms]     [k] .down_write                             
     0.74%  split-huge-page  [kernel.kallsyms]     [k] .lru_add_page_tail                      
     0.61%  split-huge-page  [kernel.kallsyms]     [k] .split_huge_page                        
     0.59%  split-huge-page  [kernel.kallsyms]     [k] .change_protection                      
     0.51%  split-huge-page  [kernel.kallsyms]     [k] .release_pages                          

     0.96%  split-huge-page  [unknown]             [H] 0x000000000157e3bc                      
	    |          
	    |--79.44%-- reloc_start
	    |          |          
	    |          |--86.54%-- .__pSeries_lpar_hugepage_invalidate
	    |          |          .pSeries_lpar_hugepage_invalidate
	    |          |          .hpte_need_hugepage_flush
	    |          |          .split_huge_page
	    |          |          .__split_huge_page_pmd
	    |          |          .vma_adjust
	    |          |          .vma_merge
	    |          |          .mprotect_fixup
	    |          |          .SyS_mprotect

THP disabled:
---------------
[root@llmp24l02 ~]# echo never > /sys/kernel/mm/transparent_hugepage/enabled
[root@llmp24l02 ~]# /root/thp/tools/perf/perf stat -e page-faults,dTLB-load-misses ./split-huge-page-mpro 20G
time taken to touch all the data in ns: 3513767220 

 Performance counter stats for './split-huge-page-mpro 20G':

	  3,27,726 page-faults                                                 
	  3,29,654 dTLB-load-misses                                            

       3.599146098 seconds time elapsed

[root@llmp24l02 ~]#

Changes from V8:
* rebase to 3.10-rc2
* make subpage protection syscall work with transparent hugepage.
* Add proper barriers when reading pgtable content stashed in the second half of PMD.

Changes from V7:
* Address review feedback.
* mm/ patches also posted as a seperate series to linux-mm list
* Fixes for races against split and page table walk.
* Updated comments regarding locking details 

Changes from V6:
* split the patch series into two patchset.
* Address review feedback.

Changes from V5:
* Address review comments
* Added new patch to not use hugepd for explcit hugepages. Explicit hugepaes
  now use PTE format similar to transparent hugepages.
* We don't use page->_mapcount for tracking free PTE frags in a PTE page.
* rebased to a86d52667d8eda5de39393ce737794403bdce1eb
* Tested with libhugetlbfs test suite

Changes from V4:
* Fix bad page error in page_table_alloc
  BUG: Bad page state in process stream  pfn:f1a59
  page:f0000000034dc378 count:1 mapcount:0 mapping:          (null) index:0x0
  [c000000f322c77d0] [c00000000015e198] .bad_page+0xe8/0x140
  [c000000f322c7860] [c00000000015e3c4] .free_pages_prepare+0x1d4/0x1e0
  [c000000f322c7910] [c000000000160450] .free_hot_cold_page+0x50/0x230
  [c000000f322c79c0] [c00000000003ad18] .page_table_alloc+0x168/0x1c0

Changes from V3:
* PowerNV boot fixes

Change from V2:
* Change patch "powerpc: Reduce PTE table memory wastage" to use much simpler approach
  for PTE page sharing.
* Changes to handle huge pages in KVM code.
* Address other review comments

Changes from V1
* Address review comments
* More patch split
* Add batch hpte invalidate for hugepages.

Changes from RFC V2:
* Address review comments
* More code cleanup and patch split

Changes from RFC V1:
* HugeTLB fs now works
* Compile issues fixed
* rebased to v3.8
* Patch series reorded so that ppc64 cleanups and MM THP changes are moved
  early in the series. This should help in picking those patches early.

Thanks,
-aneesh

[PATCH -V9 01/20] mm/THP: Use pmd_populate to update the pmd with pgtable_t pointer

[Aneesh Kumar K.V]

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

We should not use set_pmd_at to update pmd_t with pgtable_t pointer. set_pmd_at
is used to set pmd with huge pte entries and architectures like ppc64, clear
few flags from the pte when saving a new entry. Without this change we observe
bad pte errors like below on ppc64 with THP enabled.

BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 pmd:c000001ec0000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/huge_memory.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 03a89a2..362c329 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2325,7 +2325,12 @@ static void collapse_huge_page(struct mm_struct *mm,
 		pte_unmap(pte);
 		spin_lock(&mm->page_table_lock);
 		BUG_ON(!pmd_none(*pmd));
-		set_pmd_at(mm, address, pmd, _pmd);
+		/*
+		 * We can only use set_pmd_at when establishing
+		 * hugepmds and never for establishing regular pmds that
+		 * points to regular pagetables. Use pmd_populate for that
+		 */
+		pmd_populate(mm, pmd, pmd_pgtable(_pmd));
 		spin_unlock(&mm->page_table_lock);
 		anon_vma_unlock_write(vma->anon_vma);
 		goto out;
-- 
1.8.1.2

[PATCH -V9 02/20] mm/THP: Use the right function when updating access flags

[Aneesh Kumar K.V]

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

We should use pmdp_set_access_flags to update access flags. Archs like powerpc
use extra checks(_PAGE_BUSY) when updating a hugepage PTE. A set_pmd_at doesn't
do those checks. We should use set_pmd_at only when updating a none hugepage PTE.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/huge_memory.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 362c329..dab90fd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1265,7 +1265,9 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 		 * young bit, instead of the current set_pmd_at.
 		 */
 		_pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
-		set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd);
+		if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
+					  pmd, _pmd,  1))
+			update_mmu_cache_pmd(vma, addr, pmd);
 	}
 	if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
 		if (page->mapping && trylock_page(page)) {
-- 
1.8.1.2

[PATCH -V9 03/20] mm/THP: Add pmd args to pgtable deposit and withdraw APIs

[Aneesh Kumar K.V]

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

This will be later used by powerpc THP support. In powerpc we want to use
pgtable for storing the hash index values. So instead of adding them to
mm_context list, we would like to store them in the second half of pmd

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/s390/include/asm/pgtable.h     |  5 +++--
 arch/s390/mm/pgtable.c              |  5 +++--
 arch/sparc/include/asm/pgtable_64.h |  5 +++--
 arch/sparc/mm/tlb.c                 |  5 +++--
 include/asm-generic/pgtable.h       |  5 +++--
 mm/huge_memory.c                    | 18 +++++++++---------
 mm/pgtable-generic.c                |  5 +++--
 7 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 4105b82..9fba7a8 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1351,10 +1351,11 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
 #define __HAVE_ARCH_PGTABLE_DEPOSIT
-extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, , pmd_t *pmdp,
+				       pgtable_t pgtable);
 
 #define __HAVE_ARCH_PGTABLE_WITHDRAW
-extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 
 static inline int pmd_trans_splitting(pmd_t pmd)
 {
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 7805ddc..555c11d 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1118,7 +1118,8 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 	}
 }
 
-void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
 {
 	struct list_head *lh = (struct list_head *) pgtable;
 
@@ -1132,7 +1133,7 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
 	mm->pmd_huge_pte = pgtable;
 }
 
-pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
 	struct list_head *lh;
 	pgtable_t pgtable;
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 7619f2f..d22b92d 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -853,10 +853,11 @@ extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
 				 pmd_t *pmd);
 
 #define __HAVE_ARCH_PGTABLE_DEPOSIT
-extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				       pgtable_t pgtable);
 
 #define __HAVE_ARCH_PGTABLE_WITHDRAW
-extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 #endif
 
 /* Encode and de-code a swap entry */
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 83d89bc..f828dd3 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -188,7 +188,8 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 	}
 }
 
-void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
 {
 	struct list_head *lh = (struct list_head *) pgtable;
 
@@ -202,7 +203,7 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
 	mm->pmd_huge_pte = pgtable;
 }
 
-pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
 	struct list_head *lh;
 	pgtable_t pgtable;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index a59ff51..18e27c2 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -173,11 +173,12 @@ extern void pmdp_splitting_flush(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
-extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				       pgtable_t pgtable);
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
-extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dab90fd..6b785e1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -730,7 +730,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 		entry = mk_huge_pmd(page, vma);
 		page_add_new_anon_rmap(page, vma, haddr);
 		set_pmd_at(mm, haddr, pmd, entry);
-		pgtable_trans_huge_deposit(mm, pgtable);
+		pgtable_trans_huge_deposit(mm, pmd, pgtable);
 		add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
 		mm->nr_ptes++;
 		spin_unlock(&mm->page_table_lock);
@@ -772,7 +772,7 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 	entry = pmd_wrprotect(entry);
 	entry = pmd_mkhuge(entry);
 	set_pmd_at(mm, haddr, pmd, entry);
-	pgtable_trans_huge_deposit(mm, pgtable);
+	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	mm->nr_ptes++;
 	return true;
 }
@@ -917,7 +917,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	pmdp_set_wrprotect(src_mm, addr, src_pmd);
 	pmd = pmd_mkold(pmd_wrprotect(pmd));
 	set_pmd_at(dst_mm, addr, dst_pmd, pmd);
-	pgtable_trans_huge_deposit(dst_mm, pgtable);
+	pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
 	dst_mm->nr_ptes++;
 
 	ret = 0;
@@ -987,7 +987,7 @@ static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
 	pmdp_clear_flush(vma, haddr, pmd);
 	/* leave pmd empty until pte is filled */
 
-	pgtable = pgtable_trans_huge_withdraw(mm);
+	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
 	pmd_populate(mm, &_pmd, pgtable);
 
 	for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
@@ -1085,7 +1085,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 	pmdp_clear_flush(vma, haddr, pmd);
 	/* leave pmd empty until pte is filled */
 
-	pgtable = pgtable_trans_huge_withdraw(mm);
+	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
 	pmd_populate(mm, &_pmd, pgtable);
 
 	for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
@@ -1360,7 +1360,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page;
 		pgtable_t pgtable;
 		pmd_t orig_pmd;
-		pgtable = pgtable_trans_huge_withdraw(tlb->mm);
+		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
 		orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
 		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
 		if (is_huge_zero_pmd(orig_pmd)) {
@@ -1693,7 +1693,7 @@ static int __split_huge_page_map(struct page *page,
 	pmd = page_check_address_pmd(page, mm, address,
 				     PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
 	if (pmd) {
-		pgtable = pgtable_trans_huge_withdraw(mm);
+		pgtable = pgtable_trans_huge_withdraw(mm, pmd);
 		pmd_populate(mm, &_pmd, pgtable);
 
 		haddr = address;
@@ -2363,7 +2363,7 @@ static void collapse_huge_page(struct mm_struct *mm,
 	page_add_new_anon_rmap(new_page, vma, address);
 	set_pmd_at(mm, address, pmd, _pmd);
 	update_mmu_cache_pmd(vma, address, pmd);
-	pgtable_trans_huge_deposit(mm, pgtable);
+	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	spin_unlock(&mm->page_table_lock);
 
 	*hpage = NULL;
@@ -2669,7 +2669,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
 	pmdp_clear_flush(vma, haddr, pmd);
 	/* leave pmd empty until pte is filled */
 
-	pgtable = pgtable_trans_huge_withdraw(mm);
+	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
 	pmd_populate(mm, &_pmd, pgtable);
 
 	for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 0c8323f..e1a6e4f 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -124,7 +124,8 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 
 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
 {
 	assert_spin_locked(&mm->page_table_lock);
 
@@ -141,7 +142,7 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /* no "address" argument so destroys page coloring of some arch */
-pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
 	pgtable_t pgtable;
 
-- 
1.8.1.2

[PATCH -V9 04/20] mm/THP: withdraw the pgtable after pmdp related operations

[Aneesh Kumar K.V]

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

For architectures like ppc64 we look at deposited pgtable when
calling pmdp_get_and_clear. So do the pgtable_trans_huge_withdraw
after finishing pmdp related operations.

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/huge_memory.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6b785e1..5c4fac2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1360,9 +1360,15 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page;
 		pgtable_t pgtable;
 		pmd_t orig_pmd;
-		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+		/*
+		 * For architectures like ppc64 we look at deposited pgtable
+		 * when calling pmdp_get_and_clear. So do the
+		 * pgtable_trans_huge_withdraw after finishing pmdp related
+		 * operations.
+		 */
 		orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
 		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
 		if (is_huge_zero_pmd(orig_pmd)) {
 			tlb->mm->nr_ptes--;
 			spin_unlock(&tlb->mm->page_table_lock);
-- 
1.8.1.2

[PATCH -V9 05/20] mm/THP: Don't use HPAGE_SHIFT in transparent hugepage code

[Aneesh Kumar K.V]

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

For architectures like powerpc that support multiple explicit hugepage
sizes, HPAGE_SHIFT indicate the default explicit hugepage shift. For
THP to work the hugepage size should be same as PMD_SIZE. So use
PMD_SHIFT directly. So move the define outside CONFIG_TRANSPARENT_HUGEPAGE
#ifdef because we want to use these defines in generic code with
if (pmd_trans_huge()) conditional.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/linux/huge_mm.h | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 528454c..cc276d2 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -58,12 +58,11 @@ extern pmd_t *page_check_address_pmd(struct page *page,
 
 #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
 #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
+#define HPAGE_PMD_SHIFT PMD_SHIFT
+#define HPAGE_PMD_SIZE	((1UL) << HPAGE_PMD_SHIFT)
+#define HPAGE_PMD_MASK	(~(HPAGE_PMD_SIZE - 1))
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define HPAGE_PMD_SHIFT HPAGE_SHIFT
-#define HPAGE_PMD_MASK HPAGE_MASK
-#define HPAGE_PMD_SIZE HPAGE_SIZE
-
 extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
 
 #define transparent_hugepage_enabled(__vma)				\
@@ -181,9 +180,6 @@ extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vm
 				unsigned long addr, pmd_t pmd, pmd_t *pmdp);
 
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
-#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
-#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
-#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
 
 #define hpage_nr_pages(x) 1
 
-- 
1.8.1.2

[PATCH -V9 06/20] mm/THP: deposit the transpare huge pgtable before set_pmd

[Aneesh Kumar K.V]

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

Architectures like powerpc use the deposited pgtable to store
hash index values. We need to make the deposted pgtable visible
to other cpus before we are ready to take a hash fault.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/huge_memory.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5c4fac2..59d9384 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -729,8 +729,8 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 		pmd_t entry;
 		entry = mk_huge_pmd(page, vma);
 		page_add_new_anon_rmap(page, vma, haddr);
-		set_pmd_at(mm, haddr, pmd, entry);
 		pgtable_trans_huge_deposit(mm, pmd, pgtable);
+		set_pmd_at(mm, haddr, pmd, entry);
 		add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
 		mm->nr_ptes++;
 		spin_unlock(&mm->page_table_lock);
@@ -771,8 +771,8 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 	entry = mk_pmd(zero_page, vma->vm_page_prot);
 	entry = pmd_wrprotect(entry);
 	entry = pmd_mkhuge(entry);
-	set_pmd_at(mm, haddr, pmd, entry);
 	pgtable_trans_huge_deposit(mm, pmd, pgtable);
+	set_pmd_at(mm, haddr, pmd, entry);
 	mm->nr_ptes++;
 	return true;
 }
@@ -916,8 +916,8 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 
 	pmdp_set_wrprotect(src_mm, addr, src_pmd);
 	pmd = pmd_mkold(pmd_wrprotect(pmd));
-	set_pmd_at(dst_mm, addr, dst_pmd, pmd);
 	pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
+	set_pmd_at(dst_mm, addr, dst_pmd, pmd);
 	dst_mm->nr_ptes++;
 
 	ret = 0;
@@ -2367,9 +2367,9 @@ static void collapse_huge_page(struct mm_struct *mm,
 	spin_lock(&mm->page_table_lock);
 	BUG_ON(!pmd_none(*pmd));
 	page_add_new_anon_rmap(new_page, vma, address);
+	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	set_pmd_at(mm, address, pmd, _pmd);
 	update_mmu_cache_pmd(vma, address, pmd);
-	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	spin_unlock(&mm->page_table_lock);
 
 	*hpage = NULL;
-- 
1.8.1.2

[PATCH -V9 07/20] powerpc/THP: Double the PMD table size for THP

[Aneesh Kumar K.V]

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

THP code does PTE page allocation along with large page request and deposit them
for later use. This is to ensure that we won't have any failures when we split
hugepages to regular pages.

On powerpc we want to use the deposited PTE page for storing hash pte slot and
secondary bit information for the HPTEs. We use the second half
of the pmd table to save the deposted PTE page.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgalloc-64.h        | 6 +++---
 arch/powerpc/include/asm/pgtable-ppc64-64k.h | 3 ++-
 arch/powerpc/include/asm/pgtable-ppc64.h     | 6 +++++-
 arch/powerpc/mm/init_64.c                    | 9 ++++++---
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h
index b66ae72..f65e27b 100644
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -221,17 +221,17 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return kmem_cache_alloc(PGT_CACHE(PMD_INDEX_SIZE),
+	return kmem_cache_alloc(PGT_CACHE(PMD_CACHE_INDEX),
 				GFP_KERNEL|__GFP_REPEAT);
 }
 
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
-	kmem_cache_free(PGT_CACHE(PMD_INDEX_SIZE), pmd);
+	kmem_cache_free(PGT_CACHE(PMD_CACHE_INDEX), pmd);
 }
 
 #define __pmd_free_tlb(tlb, pmd, addr)		      \
-	pgtable_free_tlb(tlb, pmd, PMD_INDEX_SIZE)
+	pgtable_free_tlb(tlb, pmd, PMD_CACHE_INDEX)
 #ifndef CONFIG_PPC_64K_PAGES
 #define __pud_free_tlb(tlb, pud, addr)		      \
 	pgtable_free_tlb(tlb, pud, PUD_INDEX_SIZE)
diff --git a/arch/powerpc/include/asm/pgtable-ppc64-64k.h b/arch/powerpc/include/asm/pgtable-ppc64-64k.h
index 45142d6..a56b82f 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64-64k.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64-64k.h
@@ -33,7 +33,8 @@
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 
 /* Bits to mask out from a PMD to get to the PTE page */
-#define PMD_MASKED_BITS		0x1ff
+/* PMDs point to PTE table fragments which are 4K aligned.  */
+#define PMD_MASKED_BITS		0xfff
 /* Bits to mask out from a PGD/PUD to get to the PMD page */
 #define PUD_MASKED_BITS		0x1ff
 
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index e3d55f6f..ab84332 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -20,7 +20,11 @@
                 	    PUD_INDEX_SIZE + PGD_INDEX_SIZE + PAGE_SHIFT)
 #define PGTABLE_RANGE (ASM_CONST(1) << PGTABLE_EADDR_SIZE)
 
-
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define PMD_CACHE_INDEX	(PMD_INDEX_SIZE + 1)
+#else
+#define PMD_CACHE_INDEX	PMD_INDEX_SIZE
+#endif
 /*
  * Define the address range of the kernel non-linear virtual area
  */
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index a90b9c4..d0cd9e4 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -88,7 +88,11 @@ static void pgd_ctor(void *addr)
 
 static void pmd_ctor(void *addr)
 {
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	memset(addr, 0, PMD_TABLE_SIZE * 2);
+#else
 	memset(addr, 0, PMD_TABLE_SIZE);
+#endif
 }
 
 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
@@ -137,10 +141,9 @@ void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
 void pgtable_cache_init(void)
 {
 	pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
-	pgtable_cache_add(PMD_INDEX_SIZE, pmd_ctor);
-	if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_INDEX_SIZE))
+	pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
+	if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_CACHE_INDEX))
 		panic("Couldn't allocate pgtable caches");
-
 	/* In all current configs, when the PUD index exists it's the
 	 * same size as either the pgd or pmd index.  Verify that the
 	 * initialization above has also created a PUD cache.  This
-- 
1.8.1.2

[PATCH -V9 08/20] powerpc/THP: Implement transparent hugepages for ppc64

[Aneesh Kumar K.V]

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

We now have pmd entries covering 16MB range and the PMD table double its original size.
We use the second half of the PMD table to deposit the pgtable (PTE page).
The depoisted PTE page is further used to track the HPTE information. The information
include [ secondary group | 3 bit hidx | valid ]. We use one byte per each HPTE entry.
With 16MB hugepage and 64K HPTE we need 256 entries and with 4K HPTE we need
4096 entries. Both will fit in a 4K PTE page. On hugepage invalidate we need to walk
the PTE page and invalidate all valid HPTEs.

This patch implements necessary arch specific functions for THP support and also
hugepage invalidate logic. These PMD related functions are intentionally kept
similar to their PTE counter-part.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgtable-ppc64.h | 200 ++++++++++++++++-
 arch/powerpc/include/asm/pgtable.h       |   4 +
 arch/powerpc/include/asm/tlbflush.h      |   3 +-
 arch/powerpc/mm/pgtable_64.c             | 364 +++++++++++++++++++++++++++++++
 arch/powerpc/mm/tlb_hash64.c             |  27 +++
 arch/powerpc/platforms/Kconfig.cputype   |   1 +
 6 files changed, 597 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index ab84332..d8642fb 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -154,7 +154,7 @@
 #define	pmd_present(pmd)	(pmd_val(pmd) != 0)
 #define	pmd_clear(pmdp)		(pmd_val(*(pmdp)) = 0)
 #define pmd_page_vaddr(pmd)	(pmd_val(pmd) & ~PMD_MASKED_BITS)
-#define pmd_page(pmd)		virt_to_page(pmd_page_vaddr(pmd))
+extern struct page *pmd_page(pmd_t pmd);
 
 #define pud_set(pudp, pudval)	(pud_val(*(pudp)) = (pudval))
 #define pud_none(pud)		(!pud_val(pud))
@@ -382,4 +382,202 @@ static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
 
 #endif /* __ASSEMBLY__ */
 
+/*
+ * THP pages can't be special. So use the _PAGE_SPECIAL
+ */
+#define _PAGE_SPLITTING _PAGE_SPECIAL
+
+/*
+ * We need to differentiate between explicit huge page and THP huge
+ * page, since THP huge page also need to track real subpage details
+ */
+#define _PAGE_THP_HUGE  _PAGE_4K_PFN
+
+/*
+ * set of bits not changed in pmd_modify.
+ */
+#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS |		\
+			 _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_SPLITTING | \
+			 _PAGE_THP_HUGE)
+
+#ifndef __ASSEMBLY__
+/*
+ * The linux hugepage PMD now include the pmd entries followed by the address
+ * to the stashed pgtable_t. The stashed pgtable_t contains the hpte bits.
+ * [ 1 bit secondary | 3 bit hidx | 1 bit valid | 000]. We use one byte per
+ * each HPTE entry. With 16MB hugepage and 64K HPTE we need 256 entries and
+ * with 4K HPTE we need 4096 entries. Both will fit in a 4K pgtable_t.
+ *
+ * The last three bits are intentionally left to zero. This memory location
+ * are also used as normal page PTE pointers. So if we have any pointers
+ * left around while we collapse a hugepage, we need to make sure
+ * _PAGE_PRESENT and _PAGE_FILE bits of that are zero when we look at them
+ */
+static inline unsigned int hpte_valid(unsigned char *hpte_slot_array, int index)
+{
+	return (hpte_slot_array[index] >> 3) & 0x1;
+}
+
+static inline unsigned int hpte_hash_index(unsigned char *hpte_slot_array,
+					   int index)
+{
+	return hpte_slot_array[index] >> 4;
+}
+
+static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array,
+					unsigned int index, unsigned int hidx)
+{
+	hpte_slot_array[index] = hidx << 4 | 0x1 << 3;
+}
+
+extern void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
+				   pmd_t *pmdp);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
+extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
+extern pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot);
+extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
+		       pmd_t *pmdp, pmd_t pmd);
+extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
+				 pmd_t *pmd);
+
+static inline int pmd_trans_huge(pmd_t pmd)
+{
+	/*
+	 * leaf pte for huge page, bottom two bits != 00
+	 */
+	return (pmd_val(pmd) & 0x3) && (pmd_val(pmd) & _PAGE_THP_HUGE);
+}
+
+static inline int pmd_large(pmd_t pmd)
+{
+	/*
+	 * leaf pte for huge page, bottom two bits != 00
+	 */
+	if (pmd_trans_huge(pmd))
+		return pmd_val(pmd) & _PAGE_PRESENT;
+	return 0;
+}
+
+static inline int pmd_trans_splitting(pmd_t pmd)
+{
+	if (pmd_trans_huge(pmd))
+		return pmd_val(pmd) & _PAGE_SPLITTING;
+	return 0;
+}
+
+/* We will enable it in the last patch */
+#define has_transparent_hugepage() 0
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+static inline pte_t pmd_pte(pmd_t pmd)
+{
+	return __pte(pmd_val(pmd));
+}
+
+static inline pmd_t pte_pmd(pte_t pte)
+{
+	return __pmd(pte_val(pte));
+}
+
+static inline pte_t *pmdp_ptep(pmd_t *pmd)
+{
+	return (pte_t *)pmd;
+}
+
+#define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
+#define pmd_young(pmd)		pte_young(pmd_pte(pmd))
+#define pmd_mkold(pmd)		pte_pmd(pte_mkold(pmd_pte(pmd)))
+#define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
+#define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
+#define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
+#define pmd_mkwrite(pmd)	pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+
+#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write(pmd)		pte_write(pmd_pte(pmd))
+
+static inline pmd_t pmd_mkhuge(pmd_t pmd)
+{
+	/* Do nothing, mk_pmd() does this part.  */
+	return pmd;
+}
+
+static inline pmd_t pmd_mknotpresent(pmd_t pmd)
+{
+	pmd_val(pmd) &= ~_PAGE_PRESENT;
+	return pmd;
+}
+
+static inline pmd_t pmd_mksplitting(pmd_t pmd)
+{
+	pmd_val(pmd) |= _PAGE_SPLITTING;
+	return pmd;
+}
+
+#define __HAVE_ARCH_PMD_SAME
+static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
+{
+	return (((pmd_val(pmd_a) ^ pmd_val(pmd_b)) & ~_PAGE_HPTEFLAGS) == 0);
+}
+
+#define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+extern int pmdp_set_access_flags(struct vm_area_struct *vma,
+				 unsigned long address, pmd_t *pmdp,
+				 pmd_t entry, int dirty);
+
+extern unsigned long pmd_hugepage_update(struct mm_struct *mm,
+					 unsigned long addr,
+					 pmd_t *pmdp, unsigned long clr);
+
+static inline int __pmdp_test_and_clear_young(struct mm_struct *mm,
+					      unsigned long addr, pmd_t *pmdp)
+{
+	unsigned long old;
+
+	if ((pmd_val(*pmdp) & (_PAGE_ACCESSED | _PAGE_HASHPTE)) == 0)
+		return 0;
+	old = pmd_hugepage_update(mm, addr, pmdp, _PAGE_ACCESSED);
+	return ((old & _PAGE_ACCESSED) != 0);
+}
+
+#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
+extern int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+				     unsigned long address, pmd_t *pmdp);
+#define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
+extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
+				  unsigned long address, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMDP_GET_AND_CLEAR
+extern pmd_t pmdp_get_and_clear(struct mm_struct *mm,
+				unsigned long addr, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMDP_CLEAR_FLUSH
+extern pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
+			      pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMDP_SET_WRPROTECT
+static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr,
+				      pmd_t *pmdp)
+{
+
+	if ((pmd_val(*pmdp) & _PAGE_RW) == 0)
+		return;
+
+	pmd_hugepage_update(mm, addr, pmdp, _PAGE_RW);
+}
+
+#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
+extern void pmdp_splitting_flush(struct vm_area_struct *vma,
+				 unsigned long address, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PGTABLE_DEPOSIT
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				       pgtable_t pgtable);
+#define __HAVE_ARCH_PGTABLE_WITHDRAW
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMDP_INVALIDATE
+extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+			    pmd_t *pmdp);
+#endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 7aeb955..d53db93 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -220,6 +220,10 @@ extern int gup_hugepd(hugepd_t *hugepd, unsigned pdshift, unsigned long addr,
 
 extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 		       unsigned long end, int write, struct page **pages, int *nr);
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+#define pmd_large(pmd)		0
+#define has_transparent_hugepage() 0
+#endif
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/include/asm/tlbflush.h b/arch/powerpc/include/asm/tlbflush.h
index 61a5927..2def01ed 100644
--- a/arch/powerpc/include/asm/tlbflush.h
+++ b/arch/powerpc/include/asm/tlbflush.h
@@ -165,7 +165,8 @@ static inline void flush_tlb_kernel_range(unsigned long start,
 /* Private function for use by PCI IO mapping code */
 extern void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 				     unsigned long end);
-
+extern void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd,
+				unsigned long addr);
 #else
 #error Unsupported MMU type
 #endif
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index a854096..2ff92aa 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -338,6 +338,19 @@ EXPORT_SYMBOL(iounmap);
 EXPORT_SYMBOL(__iounmap);
 EXPORT_SYMBOL(__iounmap_at);
 
+/*
+ * For hugepage we have pfn in the pmd, we use PTE_RPN_SHIFT bits for flags
+ * For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address.
+ */
+struct page *pmd_page(pmd_t pmd)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (pmd_trans_huge(pmd))
+		return pfn_to_page(pmd_pfn(pmd));
+#endif
+	return virt_to_page(pmd_page_vaddr(pmd));
+}
+
 #ifdef CONFIG_PPC_64K_PAGES
 static pte_t *get_from_cache(struct mm_struct *mm)
 {
@@ -455,3 +468,354 @@ void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
 }
 #endif
 #endif /* CONFIG_PPC_64K_PAGES */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+/*
+ * This is called when relaxing access to a hugepage. It's also called in the page
+ * fault path when we don't hit any of the major fault cases, ie, a minor
+ * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
+ * handled those two for us, we additionally deal with missing execute
+ * permission here on some processors
+ */
+int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
+			  pmd_t *pmdp, pmd_t entry, int dirty)
+{
+	int changed;
+#ifdef CONFIG_DEBUG_VM
+	WARN_ON(!pmd_trans_huge(*pmdp));
+	assert_spin_locked(&vma->vm_mm->page_table_lock);
+#endif
+	changed = !pmd_same(*(pmdp), entry);
+	if (changed) {
+		__ptep_set_access_flags(pmdp_ptep(pmdp), pmd_pte(entry));
+		/*
+		 * Since we are not supporting SW TLB systems, we don't
+		 * have any thing similar to flush_tlb_page_nohash()
+		 */
+	}
+	return changed;
+}
+
+unsigned long pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
+				  pmd_t *pmdp, unsigned long clr)
+{
+
+	unsigned long old, tmp;
+
+#ifdef CONFIG_DEBUG_VM
+	WARN_ON(!pmd_trans_huge(*pmdp));
+	assert_spin_locked(&mm->page_table_lock);
+#endif
+
+#ifdef PTE_ATOMIC_UPDATES
+	__asm__ __volatile__(
+	"1:	ldarx	%0,0,%3\n\
+		andi.	%1,%0,%6\n\
+		bne-	1b \n\
+		andc	%1,%0,%4 \n\
+		stdcx.	%1,0,%3 \n\
+		bne-	1b"
+	: "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
+	: "r" (pmdp), "r" (clr), "m" (*pmdp), "i" (_PAGE_BUSY)
+	: "cc" );
+#else
+	old = pmd_val(*pmdp);
+	*pmdp = __pmd(old & ~clr);
+#endif
+	if (old & _PAGE_HASHPTE)
+		hpte_do_hugepage_flush(mm, addr, pmdp);
+	return old;
+}
+
+pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
+		       pmd_t *pmdp)
+{
+	pmd_t pmd;
+
+	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+	if (pmd_trans_huge(*pmdp)) {
+		pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp);
+	} else {
+		/*
+		 * khugepaged calls this for normal pmd
+		 */
+		pmd = *pmdp;
+		pmd_clear(pmdp);
+		/*
+		 * Now invalidate the hpte entries in the range
+		 * covered by pmd. This make sure we take a
+		 * fault and will find the pmd as none, which will
+		 * result in a major fault which takes mmap_sem and
+		 * hence wait for collapse to complete. Without this
+		 * the __collapse_huge_page_copy can result in copying
+		 * the old content.
+		 */
+		flush_tlb_pmd_range(vma->vm_mm, &pmd, address);
+	}
+	return pmd;
+}
+
+int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+			      unsigned long address, pmd_t *pmdp)
+{
+	return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
+}
+
+/*
+ * We currently remove entries from the hashtable regardless of whether
+ * the entry was young or dirty. The generic routines only flush if the
+ * entry was young or dirty which is not good enough.
+ *
+ * We should be more intelligent about this but for the moment we override
+ * these functions and force a tlb flush unconditionally
+ */
+int pmdp_clear_flush_young(struct vm_area_struct *vma,
+				  unsigned long address, pmd_t *pmdp)
+{
+	return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
+}
+
+/*
+ * We mark the pmd splitting and invalidate all the hpte
+ * entries for this hugepage.
+ */
+void pmdp_splitting_flush(struct vm_area_struct *vma,
+			  unsigned long address, pmd_t *pmdp)
+{
+	unsigned long old, tmp;
+
+	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+#ifdef CONFIG_DEBUG_VM
+	WARN_ON(!pmd_trans_huge(*pmdp));
+	assert_spin_locked(&vma->vm_mm->page_table_lock);
+#endif
+
+#ifdef PTE_ATOMIC_UPDATES
+
+	__asm__ __volatile__(
+	"1:	ldarx	%0,0,%3\n\
+		andi.	%1,%0,%6\n\
+		bne-	1b \n\
+		ori	%1,%0,%4 \n\
+		stdcx.	%1,0,%3 \n\
+		bne-	1b"
+	: "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
+	: "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY)
+	: "cc" );
+#else
+	old = pmd_val(*pmdp);
+	*pmdp = __pmd(old | _PAGE_SPLITTING);
+#endif
+	/*
+	 * If we didn't had the splitting flag set, go and flush the
+	 * HPTE entries.
+	 */
+	if (!(old & _PAGE_SPLITTING)) {
+		/* We need to flush the hpte */
+		if (old & _PAGE_HASHPTE)
+			hpte_do_hugepage_flush(vma->vm_mm, address, pmdp);
+	}
+}
+
+/*
+ * We want to put the pgtable in pmd and use pgtable for tracking
+ * the base page size hptes
+ */
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
+{
+	pgtable_t *pgtable_slot;
+	assert_spin_locked(&mm->page_table_lock);
+	/*
+	 * we store the pgtable in the second half of PMD
+	 */
+	pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+	*pgtable_slot = pgtable;
+	/*
+	 * expose the deposited pgtable to other cpus.
+	 * before we set the hugepage PTE at pmd level
+	 * hash fault code looks at the deposted pgtable
+	 * to store hash index values.
+	 */
+	smp_wmb();
+}
+
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
+{
+	pgtable_t pgtable;
+	pgtable_t *pgtable_slot;
+
+	assert_spin_locked(&mm->page_table_lock);
+	pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+	pgtable = *pgtable_slot;
+	/*
+	 * Once we withdraw, mark the entry NULL.
+	 */
+	*pgtable_slot = NULL;
+	/*
+	 * We store HPTE information in the deposited PTE fragment.
+	 * zero out the content on withdraw.
+	 */
+	memset(pgtable, 0, PTE_FRAG_SIZE);
+	return pgtable;
+}
+
+/*
+ * set a new huge pmd. We should not be called for updating
+ * an existing pmd entry. That should go via pmd_hugepage_update.
+ */
+void set_pmd_at(struct mm_struct *mm, unsigned long addr,
+		pmd_t *pmdp, pmd_t pmd)
+{
+#ifdef CONFIG_DEBUG_VM
+	WARN_ON(!pmd_none(*pmdp));
+	assert_spin_locked(&mm->page_table_lock);
+	WARN_ON(!pmd_trans_huge(pmd));
+#endif
+	return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
+}
+
+void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+		     pmd_t *pmdp)
+{
+	pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT);
+}
+
+/*
+ * A linux hugepage PMD was changed and the corresponding hash table entries
+ * neesd to be flushed.
+ */
+void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
+			    pmd_t *pmdp)
+{
+	int ssize, i;
+	unsigned long s_addr;
+	unsigned int psize, valid;
+	unsigned char *hpte_slot_array;
+	unsigned long hidx, vpn, vsid, hash, shift, slot;
+
+	/*
+	 * Flush all the hptes mapping this hugepage
+	 */
+	s_addr = addr & HPAGE_PMD_MASK;
+	/*
+	 * The hpte hindex are stored in the pgtable whose address is in the
+	 * second half of the PMD
+	 */
+	hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+	/*
+	 * IF we try to do a HUGE PTE update after a withdraw is done.
+	 * we will find the below NULL. This happens when we do
+	 * split_huge_page_pmd
+	 */
+	if (!hpte_slot_array)
+		return;
+
+	/* get the base page size */
+	psize = get_slice_psize(mm, s_addr);
+	shift = mmu_psize_defs[psize].shift;
+
+	for (i = 0; i < (HPAGE_PMD_SIZE >> shift); i++) {
+		/*
+		 * 8 bits per each hpte entries
+		 * 000| [ secondary group (one bit) | hidx (3 bits) | valid bit]
+		 */
+		valid = hpte_valid(hpte_slot_array, i);
+		if (!valid)
+			continue;
+		hidx =  hpte_hash_index(hpte_slot_array, i);
+
+		/* get the vpn */
+		addr = s_addr + (i * (1ul << shift));
+		if (!is_kernel_addr(addr)) {
+			ssize = user_segment_size(addr);
+			vsid = get_vsid(mm->context.id, addr, ssize);
+			WARN_ON(vsid == 0);
+		} else {
+			vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+			ssize = mmu_kernel_ssize;
+		}
+
+		vpn = hpt_vpn(addr, vsid, ssize);
+		hash = hpt_hash(vpn, shift, ssize);
+		if (hidx & _PTEIDX_SECONDARY)
+			hash = ~hash;
+
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += hidx & _PTEIDX_GROUP_IX;
+		ppc_md.hpte_invalidate(slot, vpn, psize, ssize, 0);
+	}
+}
+
+static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
+{
+	pmd_val(pmd) |= pgprot_val(pgprot);
+	return pmd;
+}
+
+pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
+{
+	pmd_t pmd;
+	/*
+	 * For a valid pte, we would have _PAGE_PRESENT or _PAGE_FILE always
+	 * set. We use this to check THP page at pmd level.
+	 * leaf pte for huge page, bottom two bits != 00
+	 */
+	pmd_val(pmd) = pfn << PTE_RPN_SHIFT;
+	pmd_val(pmd) |= _PAGE_THP_HUGE;
+	pmd = pmd_set_protbits(pmd, pgprot);
+	return pmd;
+}
+
+pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
+{
+	return pfn_pmd(page_to_pfn(page), pgprot);
+}
+
+pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+
+	pmd_val(pmd) &= _HPAGE_CHG_MASK;
+	pmd = pmd_set_protbits(pmd, newprot);
+	return pmd;
+}
+
+/*
+ * This is called at the end of handling a user page fault, when the
+ * fault has been handled by updating a HUGE PMD entry in the linux page tables.
+ * We use it to preload an HPTE into the hash table corresponding to
+ * the updated linux HUGE PMD entry.
+ */
+void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
+			  pmd_t *pmd)
+{
+	return;
+}
+
+pmd_t pmdp_get_and_clear(struct mm_struct *mm,
+			 unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t old_pmd;
+	pgtable_t pgtable;
+	unsigned long old;
+	pgtable_t *pgtable_slot;
+
+	old = pmd_hugepage_update(mm, addr, pmdp, ~0UL);
+	old_pmd = __pmd(old);
+	/*
+	 * We have pmd == none and we are holding page_table_lock.
+	 * So we can safely go and clear the pgtable hash
+	 * index info.
+	 */
+	pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+	pgtable = *pgtable_slot;
+	/*
+	 * Let's zero out old valid and hash index details
+	 * hash fault look at them.
+	 */
+	memset(pgtable, 0, PTE_FRAG_SIZE);
+	return old_pmd;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index 023ec8a..48bf63e 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -219,3 +219,30 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 	arch_leave_lazy_mmu_mode();
 	local_irq_restore(flags);
 }
+
+void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr)
+{
+	pte_t *pte;
+	pte_t *start_pte;
+	unsigned long flags;
+
+	addr = _ALIGN_DOWN(addr, PMD_SIZE);
+	/* Note: Normally, we should only ever use a batch within a
+	 * PTE locked section. This violates the rule, but will work
+	 * since we don't actually modify the PTEs, we just flush the
+	 * hash while leaving the PTEs intact (including their reference
+	 * to being hashed). This is not the most performance oriented
+	 * way to do things but is fine for our needs here.
+	 */
+	local_irq_save(flags);
+	arch_enter_lazy_mmu_mode();
+	start_pte = pte_offset_map(pmd, addr);
+	for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) {
+		unsigned long pteval = pte_val(*pte);
+		if (pteval & _PAGE_HASHPTE)
+			hpte_need_flush(mm, addr, pte, pteval, 0);
+		addr += PAGE_SIZE;
+	}
+	arch_leave_lazy_mmu_mode();
+	local_irq_restore(flags);
+}
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 54f3936..ae0aaea 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -71,6 +71,7 @@ config PPC_BOOK3S_64
 	select PPC_FPU
 	select PPC_HAVE_PMU_SUPPORT
 	select SYS_SUPPORTS_HUGETLBFS
+	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if PPC_64K_PAGES
 
 config PPC_BOOK3E_64
 	bool "Embedded processors"
-- 
1.8.1.2

[PATCH -V9 09/20] powerpc: move find_linux_pte_or_hugepte and gup_hugepte to common code

[Aneesh Kumar K.V]

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

We will use this in the later patch for handling THP pages

Reviewed-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/hugetlb.h       |   8 +-
 arch/powerpc/include/asm/pgtable-ppc64.h |  13 --
 arch/powerpc/include/asm/pgtable.h       |   2 +
 arch/powerpc/mm/Makefile                 |   2 +-
 arch/powerpc/mm/hugetlbpage.c            | 251 ++++++++++++++++---------------
 5 files changed, 138 insertions(+), 138 deletions(-)

diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index f2498c8..d750336 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -191,8 +191,14 @@ static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 				      unsigned long vmaddr)
 {
 }
-#endif /* CONFIG_HUGETLB_PAGE */
 
+#define hugepd_shift(x) 0
+static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
+				    unsigned pdshift)
+{
+	return 0;
+}
+#endif /* CONFIG_HUGETLB_PAGE */
 
 /*
  * FSL Book3E platforms require special gpage handling - the gpages
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index d8642fb..74ce13b 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -367,19 +367,6 @@ static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea)
 	return pt;
 }
 
-#ifdef CONFIG_HUGETLB_PAGE
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
-				 unsigned *shift);
-#else
-static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
-					       unsigned *shift)
-{
-	if (shift)
-		*shift = 0;
-	return find_linux_pte(pgdir, ea);
-}
-#endif /* !CONFIG_HUGETLB_PAGE */
-
 #endif /* __ASSEMBLY__ */
 
 /*
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index d53db93..959d575 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -224,6 +224,8 @@ extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 #define pmd_large(pmd)		0
 #define has_transparent_hugepage() 0
 #endif
+pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+				 unsigned *shift);
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index cf16b57..fde36e6 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -28,8 +28,8 @@ obj-$(CONFIG_44x)		+= 44x_mmu.o
 obj-$(CONFIG_PPC_FSL_BOOK3E)	+= fsl_booke_mmu.o
 obj-$(CONFIG_NEED_MULTIPLE_NODES) += numa.o
 obj-$(CONFIG_PPC_MM_SLICES)	+= slice.o
-ifeq ($(CONFIG_HUGETLB_PAGE),y)
 obj-y				+= hugetlbpage.o
+ifeq ($(CONFIG_HUGETLB_PAGE),y)
 obj-$(CONFIG_PPC_STD_MMU_64)	+= hugetlbpage-hash64.o
 obj-$(CONFIG_PPC_BOOK3E_MMU)	+= hugetlbpage-book3e.o
 endif
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 237c8e5..2865077 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -21,6 +21,9 @@
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 #include <asm/setup.h>
+#include <asm/hugetlb.h>
+
+#ifdef CONFIG_HUGETLB_PAGE
 
 #define PAGE_SHIFT_64K	16
 #define PAGE_SHIFT_16M	24
@@ -100,66 +103,6 @@ int pgd_huge(pgd_t pgd)
 }
 #endif
 
-/*
- * We have 4 cases for pgds and pmds:
- * (1) invalid (all zeroes)
- * (2) pointer to next table, as normal; bottom 6 bits == 0
- * (3) leaf pte for huge page, bottom two bits != 00
- * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
- */
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
-{
-	pgd_t *pg;
-	pud_t *pu;
-	pmd_t *pm;
-	pte_t *ret_pte;
-	hugepd_t *hpdp = NULL;
-	unsigned pdshift = PGDIR_SHIFT;
-
-	if (shift)
-		*shift = 0;
-
-	pg = pgdir + pgd_index(ea);
-
-	if (pgd_huge(*pg)) {
-		ret_pte = (pte_t *) pg;
-		goto out;
-	} else if (is_hugepd(pg))
-		hpdp = (hugepd_t *)pg;
-	else if (!pgd_none(*pg)) {
-		pdshift = PUD_SHIFT;
-		pu = pud_offset(pg, ea);
-
-		if (pud_huge(*pu)) {
-			ret_pte = (pte_t *) pu;
-			goto out;
-		} else if (is_hugepd(pu))
-			hpdp = (hugepd_t *)pu;
-		else if (!pud_none(*pu)) {
-			pdshift = PMD_SHIFT;
-			pm = pmd_offset(pu, ea);
-
-			if (pmd_huge(*pm)) {
-				ret_pte = (pte_t *) pm;
-				goto out;
-			} else if (is_hugepd(pm))
-				hpdp = (hugepd_t *)pm;
-			else if (!pmd_none(*pm))
-				return pte_offset_kernel(pm, ea);
-		}
-	}
-	if (!hpdp)
-		return NULL;
-
-	ret_pte = hugepte_offset(hpdp, ea, pdshift);
-	pdshift = hugepd_shift(*hpdp);
-out:
-	if (shift)
-		*shift = pdshift;
-	return ret_pte;
-}
-EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
-
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {
 	return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
@@ -753,69 +696,6 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 	return NULL;
 }
 
-int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
-		unsigned long end, int write, struct page **pages, int *nr)
-{
-	unsigned long mask;
-	unsigned long pte_end;
-	struct page *head, *page, *tail;
-	pte_t pte;
-	int refs;
-
-	pte_end = (addr + sz) & ~(sz-1);
-	if (pte_end < end)
-		end = pte_end;
-
-	pte = *ptep;
-	mask = _PAGE_PRESENT | _PAGE_USER;
-	if (write)
-		mask |= _PAGE_RW;
-
-	if ((pte_val(pte) & mask) != mask)
-		return 0;
-
-	/* hugepages are never "special" */
-	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
-
-	refs = 0;
-	head = pte_page(pte);
-
-	page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
-	tail = page;
-	do {
-		VM_BUG_ON(compound_head(page) != head);
-		pages[*nr] = page;
-		(*nr)++;
-		page++;
-		refs++;
-	} while (addr += PAGE_SIZE, addr != end);
-
-	if (!page_cache_add_speculative(head, refs)) {
-		*nr -= refs;
-		return 0;
-	}
-
-	if (unlikely(pte_val(pte) != pte_val(*ptep))) {
-		/* Could be optimized better */
-		*nr -= refs;
-		while (refs--)
-			put_page(head);
-		return 0;
-	}
-
-	/*
-	 * Any tail page need their mapcount reference taken before we
-	 * return.
-	 */
-	while (refs--) {
-		if (PageTail(tail))
-			get_huge_page_tail(tail);
-		tail++;
-	}
-
-	return 1;
-}
-
 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
 				      unsigned long sz)
 {
@@ -1032,3 +912,128 @@ void flush_dcache_icache_hugepage(struct page *page)
 		}
 	}
 }
+
+#endif /* CONFIG_HUGETLB_PAGE */
+
+/*
+ * We have 4 cases for pgds and pmds:
+ * (1) invalid (all zeroes)
+ * (2) pointer to next table, as normal; bottom 6 bits == 0
+ * (3) leaf pte for huge page, bottom two bits != 00
+ * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
+ */
+pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
+{
+	pgd_t *pg;
+	pud_t *pu;
+	pmd_t *pm;
+	pte_t *ret_pte;
+	hugepd_t *hpdp = NULL;
+	unsigned pdshift = PGDIR_SHIFT;
+
+	if (shift)
+		*shift = 0;
+
+	pg = pgdir + pgd_index(ea);
+
+	if (pgd_huge(*pg)) {
+		ret_pte = (pte_t *) pg;
+		goto out;
+	} else if (is_hugepd(pg))
+		hpdp = (hugepd_t *)pg;
+	else if (!pgd_none(*pg)) {
+		pdshift = PUD_SHIFT;
+		pu = pud_offset(pg, ea);
+
+		if (pud_huge(*pu)) {
+			ret_pte = (pte_t *) pu;
+			goto out;
+		} else if (is_hugepd(pu))
+			hpdp = (hugepd_t *)pu;
+		else if (!pud_none(*pu)) {
+			pdshift = PMD_SHIFT;
+			pm = pmd_offset(pu, ea);
+
+			if (pmd_huge(*pm)) {
+				ret_pte = (pte_t *) pm;
+				goto out;
+			} else if (is_hugepd(pm))
+				hpdp = (hugepd_t *)pm;
+			else if (!pmd_none(*pm))
+				return pte_offset_kernel(pm, ea);
+		}
+	}
+	if (!hpdp)
+		return NULL;
+
+	ret_pte = hugepte_offset(hpdp, ea, pdshift);
+	pdshift = hugepd_shift(*hpdp);
+out:
+	if (shift)
+		*shift = pdshift;
+	return ret_pte;
+}
+EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
+
+int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
+		unsigned long end, int write, struct page **pages, int *nr)
+{
+	unsigned long mask;
+	unsigned long pte_end;
+	struct page *head, *page, *tail;
+	pte_t pte;
+	int refs;
+
+	pte_end = (addr + sz) & ~(sz-1);
+	if (pte_end < end)
+		end = pte_end;
+
+	pte = *ptep;
+	mask = _PAGE_PRESENT | _PAGE_USER;
+	if (write)
+		mask |= _PAGE_RW;
+
+	if ((pte_val(pte) & mask) != mask)
+		return 0;
+
+	/* hugepages are never "special" */
+	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+
+	refs = 0;
+	head = pte_page(pte);
+
+	page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
+	tail = page;
+	do {
+		VM_BUG_ON(compound_head(page) != head);
+		pages[*nr] = page;
+		(*nr)++;
+		page++;
+		refs++;
+	} while (addr += PAGE_SIZE, addr != end);
+
+	if (!page_cache_add_speculative(head, refs)) {
+		*nr -= refs;
+		return 0;
+	}
+
+	if (unlikely(pte_val(pte) != pte_val(*ptep))) {
+		/* Could be optimized better */
+		*nr -= refs;
+		while (refs--)
+			put_page(head);
+		return 0;
+	}
+
+	/*
+	 * Any tail page need their mapcount reference taken before we
+	 * return.
+	 */
+	while (refs--) {
+		if (PageTail(tail))
+			get_huge_page_tail(tail);
+		tail++;
+	}
+
+	return 1;
+}
-- 
1.8.1.2

[PATCH -V9 10/20] powerpc: Update find_linux_pte_or_hugepte to handle transparent hugepages

[Aneesh Kumar K.V]

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

Reviewed-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hugetlbpage.c | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 2865077..4928204 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -936,30 +936,50 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
 
 	pg = pgdir + pgd_index(ea);
 
-	if (pgd_huge(*pg)) {
+	/*
+	 * we should first check for none. That takes care of a
+	 * a parallel hugetlb or THP pagefault moving none entries
+	 * to respective types.
+	 */
+	if (pgd_none(*pg))
+		return NULL;
+	else if (pgd_huge(*pg)) {
 		ret_pte = (pte_t *) pg;
 		goto out;
 	} else if (is_hugepd(pg))
 		hpdp = (hugepd_t *)pg;
-	else if (!pgd_none(*pg)) {
+	else {
 		pdshift = PUD_SHIFT;
 		pu = pud_offset(pg, ea);
 
-		if (pud_huge(*pu)) {
+		if (pud_none(*pu))
+			return NULL;
+		else if (pud_huge(*pu)) {
 			ret_pte = (pte_t *) pu;
 			goto out;
 		} else if (is_hugepd(pu))
 			hpdp = (hugepd_t *)pu;
-		else if (!pud_none(*pu)) {
+		else {
 			pdshift = PMD_SHIFT;
 			pm = pmd_offset(pu, ea);
+			/*
+			 * A hugepage collapse is captured by pmd_none, because
+			 * it mark the pmd none and do a hpte invalidate.
+			 *
+			 * A hugepage split is captured by pmd_trans_splitting
+			 * because we mark the pmd trans splitting and do a
+			 * hpte invalidate
+			 *
+			 */
+			if (pmd_none(*pm) || pmd_trans_splitting(*pm))
+				return NULL;
 
-			if (pmd_huge(*pm)) {
+			if (pmd_huge(*pm) || pmd_large(*pm)) {
 				ret_pte = (pte_t *) pm;
 				goto out;
 			} else if (is_hugepd(pm))
 				hpdp = (hugepd_t *)pm;
-			else if (!pmd_none(*pm))
+			else
 				return pte_offset_kernel(pm, ea);
 		}
 	}
-- 
1.8.1.2

[PATCH -V9 11/20] powerpc: Replace find_linux_pte with find_linux_pte_or_hugepte

[Aneesh Kumar K.V]

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

Replace find_linux_pte with find_linux_pte_or_hugepte and explicitly
document why we don't need to handle transparent hugepages at callsites.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgtable-ppc64.h | 24 ------------------------
 arch/powerpc/kernel/io-workarounds.c     | 10 ++++++++--
 arch/powerpc/kvm/book3s_hv_rm_mmu.c      |  2 +-
 arch/powerpc/mm/hash_utils_64.c          |  8 +++++++-
 arch/powerpc/mm/hugetlbpage.c            |  8 ++++++--
 arch/powerpc/mm/tlb_hash64.c             |  9 +++++++--
 arch/powerpc/platforms/pseries/eeh.c     |  7 ++++++-
 7 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index 74ce13b..69cb52b 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -343,30 +343,6 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
 
 void pgtable_cache_add(unsigned shift, void (*ctor)(void *));
 void pgtable_cache_init(void);
-
-/*
- * find_linux_pte returns the address of a linux pte for a given
- * effective address and directory.  If not found, it returns zero.
- */
-static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea)
-{
-	pgd_t *pg;
-	pud_t *pu;
-	pmd_t *pm;
-	pte_t *pt = NULL;
-
-	pg = pgdir + pgd_index(ea);
-	if (!pgd_none(*pg)) {
-		pu = pud_offset(pg, ea);
-		if (!pud_none(*pu)) {
-			pm = pmd_offset(pu, ea);
-			if (pmd_present(*pm))
-				pt = pte_offset_kernel(pm, ea);
-		}
-	}
-	return pt;
-}
-
 #endif /* __ASSEMBLY__ */
 
 /*
diff --git a/arch/powerpc/kernel/io-workarounds.c b/arch/powerpc/kernel/io-workarounds.c
index 50e90b7..e5263ab 100644
--- a/arch/powerpc/kernel/io-workarounds.c
+++ b/arch/powerpc/kernel/io-workarounds.c
@@ -55,6 +55,7 @@ static struct iowa_bus *iowa_pci_find(unsigned long vaddr, unsigned long paddr)
 
 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
 {
+	unsigned shift;
 	struct iowa_bus *bus;
 	int token;
 
@@ -70,11 +71,16 @@ struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
 		if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
 			return NULL;
 
-		ptep = find_linux_pte(init_mm.pgd, vaddr);
+		ptep = find_linux_pte_or_hugepte(init_mm.pgd, vaddr, &shift);
 		if (ptep == NULL)
 			paddr = 0;
-		else
+		else {
+			/*
+			 * we don't have hugepages backing iomem
+			 */
+			BUG_ON(shift);
 			paddr = pte_pfn(*ptep) << PAGE_SHIFT;
+		}
 		bus = iowa_pci_find(vaddr, paddr);
 
 		if (bus == NULL)
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 6dcbb49..dcf892d 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -27,7 +27,7 @@ static void *real_vmalloc_addr(void *x)
 	unsigned long addr = (unsigned long) x;
 	pte_t *p;
 
-	p = find_linux_pte(swapper_pg_dir, addr);
+	p = find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
 	if (!p || !pte_present(*p))
 		return NULL;
 	/* assume we don't have huge pages in vmalloc space... */
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index e303a6d..7f9415f 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1145,6 +1145,7 @@ EXPORT_SYMBOL_GPL(hash_page);
 void hash_preload(struct mm_struct *mm, unsigned long ea,
 		  unsigned long access, unsigned long trap)
 {
+	int shift;
 	unsigned long vsid;
 	pgd_t *pgdir;
 	pte_t *ptep;
@@ -1166,10 +1167,15 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 	pgdir = mm->pgd;
 	if (pgdir == NULL)
 		return;
-	ptep = find_linux_pte(pgdir, ea);
+	/*
+	 * THP pages use update_mmu_cache_pmd. We don't do
+	 * hash preload there. Hence can ignore THP here
+	 */
+	ptep = find_linux_pte_or_hugepte(pgdir, ea, &shift);
 	if (!ptep)
 		return;
 
+	BUG_ON(shift);
 #ifdef CONFIG_PPC_64K_PAGES
 	/* If either _PAGE_4K_PFN or _PAGE_NO_CACHE is set (and we are on
 	 * a 64K kernel), then we don't preload, hash_page() will take
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 4928204..8add580 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -105,6 +105,7 @@ int pgd_huge(pgd_t pgd)
 
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {
+	/* Only called for hugetlbfs pages, hence can ignore THP */
 	return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
 }
 
@@ -673,11 +674,14 @@ follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 	struct page *page;
 	unsigned shift;
 	unsigned long mask;
-
+	/*
+	 * Transparent hugepages are handled by generic code. We can skip them
+	 * here.
+	 */
 	ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
 
 	/* Verify it is a huge page else bail. */
-	if (!ptep || !shift)
+	if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep))
 		return ERR_PTR(-EINVAL);
 
 	mask = (1UL << shift) - 1;
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index 48bf63e..313c85c 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -189,6 +189,7 @@ void tlb_flush(struct mmu_gather *tlb)
 void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 			      unsigned long end)
 {
+	int hugepage_shift;
 	unsigned long flags;
 
 	start = _ALIGN_DOWN(start, PAGE_SIZE);
@@ -206,7 +207,8 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 	local_irq_save(flags);
 	arch_enter_lazy_mmu_mode();
 	for (; start < end; start += PAGE_SIZE) {
-		pte_t *ptep = find_linux_pte(mm->pgd, start);
+		pte_t *ptep = find_linux_pte_or_hugepte(mm->pgd, start,
+							&hugepage_shift);
 		unsigned long pte;
 
 		if (ptep == NULL)
@@ -214,7 +216,10 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
 		pte = pte_val(*ptep);
 		if (!(pte & _PAGE_HASHPTE))
 			continue;
-		hpte_need_flush(mm, start, ptep, pte, 0);
+		if (unlikely(hugepage_shift && pmd_trans_huge(*(pmd_t *)pte)))
+			hpte_do_hugepage_flush(mm, start, (pmd_t *)pte);
+		else
+			hpte_need_flush(mm, start, ptep, pte, 0);
 	}
 	arch_leave_lazy_mmu_mode();
 	local_irq_restore(flags);
diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c
index 6b73d6c..d2e76d2 100644
--- a/arch/powerpc/platforms/pseries/eeh.c
+++ b/arch/powerpc/platforms/pseries/eeh.c
@@ -258,12 +258,17 @@ void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
  */
 static inline unsigned long eeh_token_to_phys(unsigned long token)
 {
+	int shift;
 	pte_t *ptep;
 	unsigned long pa;
 
-	ptep = find_linux_pte(init_mm.pgd, token);
+	/*
+	 * We won't find hugepages here, iomem
+	 */
+	ptep = find_linux_pte_or_hugepte(init_mm.pgd, token, &shift);
 	if (!ptep)
 		return token;
+	BUG_ON(shift);
 	pa = pte_pfn(*ptep) << PAGE_SHIFT;
 
 	return pa | (token & (PAGE_SIZE-1));
-- 
1.8.1.2

[PATCH -V9 12/20] powerpc: Update gup_pmd_range to handle transparent hugepages

[Aneesh Kumar K.V]

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

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/gup.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index 4b921af..3d36fd7 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -66,9 +66,20 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 		pmd_t pmd = *pmdp;
 
 		next = pmd_addr_end(addr, end);
-		if (pmd_none(pmd))
+		/*
+		 * The pmd_trans_splitting() check below explains why
+		 * pmdp_splitting_flush has to flush the tlb, to stop
+		 * this gup-fast code from running while we set the
+		 * splitting bit in the pmd. Returning zero will take
+		 * the slow path that will call wait_split_huge_page()
+		 * if the pmd is still in splitting state. gup-fast
+		 * can't because it has irq disabled and
+		 * wait_split_huge_page() would never return as the
+		 * tlb flush IPI wouldn't run.
+		 */
+		if (pmd_none(pmd) || pmd_trans_splitting(pmd))
 			return 0;
-		if (pmd_huge(pmd)) {
+		if (pmd_huge(pmd) || pmd_large(pmd)) {
 			if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
 					 write, pages, nr))
 				return 0;
-- 
1.8.1.2

[PATCH -V9 13/20] powerpc/THP: Add code to handle HPTE faults for hugepages

[Aneesh Kumar K.V]

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

The deposted PTE page in the second half of the PMD table is used to
track the state on hash PTEs. After updating the HPTE, we mark the
coresponding slot in the deposted PTE page valid.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/mmu-hash64.h |  13 +++
 arch/powerpc/mm/Makefile              |   1 +
 arch/powerpc/mm/hash_utils_64.c       |  21 +++-
 arch/powerpc/mm/hugepage-hash64.c     | 176 ++++++++++++++++++++++++++++++++++
 4 files changed, 207 insertions(+), 4 deletions(-)
 create mode 100644 arch/powerpc/mm/hugepage-hash64.c

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 2accc96..3d6fbb0 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -340,6 +340,19 @@ extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
 int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
 		     pte_t *ptep, unsigned long trap, int local, int ssize,
 		     unsigned int shift, unsigned int mmu_psize);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int __hash_page_thp(unsigned long ea, unsigned long access,
+			   unsigned long vsid, pmd_t *pmdp, unsigned long trap,
+			   int local, int ssize, unsigned int psize);
+#else
+static inline int __hash_page_thp(unsigned long ea, unsigned long access,
+				  unsigned long vsid, pmd_t *pmdp,
+				  unsigned long trap, int local,
+				  int ssize, unsigned int psize)
+{
+	BUG();
+}
+#endif
 extern void hash_failure_debug(unsigned long ea, unsigned long access,
 			       unsigned long vsid, unsigned long trap,
 			       int ssize, int psize, int lpsize,
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index fde36e6..87671eb 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -33,6 +33,7 @@ ifeq ($(CONFIG_HUGETLB_PAGE),y)
 obj-$(CONFIG_PPC_STD_MMU_64)	+= hugetlbpage-hash64.o
 obj-$(CONFIG_PPC_BOOK3E_MMU)	+= hugetlbpage-book3e.o
 endif
+obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += hugepage-hash64.o
 obj-$(CONFIG_PPC_SUBPAGE_PROT)	+= subpage-prot.o
 obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
 obj-$(CONFIG_HIGHMEM)		+= highmem.o
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 7f9415f..aad140b 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1050,13 +1050,26 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
 		goto bail;
 	}
 
-#ifdef CONFIG_HUGETLB_PAGE
 	if (hugeshift) {
-		rc = __hash_page_huge(ea, access, vsid, ptep, trap, local,
-					ssize, hugeshift, psize);
+		if (pmd_trans_huge(*(pmd_t *)ptep))
+			rc = __hash_page_thp(ea, access, vsid, (pmd_t *)ptep,
+					     trap, local, ssize, psize);
+#ifdef CONFIG_HUGETLB_PAGE
+		else
+			rc = __hash_page_huge(ea, access, vsid, ptep, trap,
+					      local, ssize, hugeshift, psize);
+#else
+		else {
+			/*
+			 * if we have hugeshift, and is not transhuge with
+			 * hugetlb disabled, something is really wrong.
+			 */
+			rc = 1;
+			WARN_ON(1);
+		}
+#endif
 		goto bail;
 	}
-#endif /* CONFIG_HUGETLB_PAGE */
 
 #ifndef CONFIG_PPC_64K_PAGES
 	DBG_LOW(" i-pte: %016lx\n", pte_val(*ptep));
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
new file mode 100644
index 0000000..3712e80
--- /dev/null
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright IBM Corporation, 2013
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+/*
+ * PPC64 THP Support for hash based MMUs
+ */
+#include <linux/mm.h>
+#include <asm/machdep.h>
+
+int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
+		    pmd_t *pmdp, unsigned long trap, int local, int ssize,
+		    unsigned int psize)
+{
+	unsigned int index, valid;
+	unsigned char *hpte_slot_array;
+	unsigned long rflags, pa, hidx;
+	unsigned long old_pmd, new_pmd;
+	int ret, lpsize = MMU_PAGE_16M;
+	unsigned long vpn, hash, shift, slot;
+
+	/*
+	 * atomically mark the linux large page PMD busy and dirty
+	 */
+	do {
+		old_pmd = pmd_val(*pmdp);
+		/* If PMD busy, retry the access */
+		if (unlikely(old_pmd & _PAGE_BUSY))
+			return 0;
+		/* If PMD permissions don't match, take page fault */
+		if (unlikely(access & ~old_pmd))
+			return 1;
+		/*
+		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
+		 * a write access
+		 */
+		new_pmd = old_pmd | _PAGE_BUSY | _PAGE_ACCESSED;
+		if (access & _PAGE_RW)
+			new_pmd |= _PAGE_DIRTY;
+	} while (old_pmd != __cmpxchg_u64((unsigned long *)pmdp,
+					  old_pmd, new_pmd));
+	/*
+	 * PP bits. _PAGE_USER is already PP bit 0x2, so we only
+	 * need to add in 0x1 if it's a read-only user page
+	 */
+	rflags = new_pmd & _PAGE_USER;
+	if ((new_pmd & _PAGE_USER) && !((new_pmd & _PAGE_RW) &&
+					   (new_pmd & _PAGE_DIRTY)))
+		rflags |= 0x1;
+	/*
+	 * _PAGE_EXEC -> HW_NO_EXEC since it's inverted
+	 */
+	rflags |= ((new_pmd & _PAGE_EXEC) ? 0 : HPTE_R_N);
+
+#if 0
+	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+
+		/*
+		 * No CPU has hugepages but lacks no execute, so we
+		 * don't need to worry about that case
+		 */
+		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
+	}
+#endif
+	/*
+	 * Find the slot index details for this ea, using base page size.
+	 */
+	shift = mmu_psize_defs[psize].shift;
+	index = (ea & ~HPAGE_PMD_MASK) >> shift;
+	BUG_ON(index >= 4096);
+
+	vpn = hpt_vpn(ea, vsid, ssize);
+	hash = hpt_hash(vpn, shift, ssize);
+	/*
+	 * The hpte hindex are stored in the pgtable whose address is in the
+	 * second half of the PMD
+	 */
+	hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+
+	valid = hpte_valid(hpte_slot_array, index);
+	if (valid) {
+		/* update the hpte bits */
+		hidx =  hpte_hash_index(hpte_slot_array, index);
+		if (hidx & _PTEIDX_SECONDARY)
+			hash = ~hash;
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += hidx & _PTEIDX_GROUP_IX;
+
+		ret = ppc_md.hpte_updatepp(slot, rflags, vpn,
+					   psize, ssize, local);
+		/*
+		 * We failed to update, try to insert a new entry.
+		 */
+		if (ret == -1) {
+			/*
+			 * large pte is marked busy, so we can be sure
+			 * nobody is looking at hpte_slot_array. hence we can
+			 * safely update this here.
+			 */
+			valid = 0;
+			new_pmd &= ~_PAGE_HPTEFLAGS;
+			hpte_slot_array[index] = 0;
+		} else
+			/* clear the busy bits and set the hash pte bits */
+			new_pmd = (new_pmd & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
+	}
+
+	if (!valid) {
+		unsigned long hpte_group;
+
+		/* insert new entry */
+		pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT;
+repeat:
+		hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
+
+		/* clear the busy bits and set the hash pte bits */
+		new_pmd = (new_pmd & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
+
+		/* Add in WIMG bits */
+		rflags |= (new_pmd & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+				      _PAGE_COHERENT | _PAGE_GUARDED));
+
+		/* Insert into the hash table, primary slot */
+		slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,
+					  psize, lpsize, ssize);
+		/*
+		 * Primary is full, try the secondary
+		 */
+		if (unlikely(slot == -1)) {
+			hpte_group = ((~hash & htab_hash_mask) *
+				      HPTES_PER_GROUP) & ~0x7UL;
+			slot = ppc_md.hpte_insert(hpte_group, vpn, pa,
+						  rflags, HPTE_V_SECONDARY,
+						  psize, lpsize, ssize);
+			if (slot == -1) {
+				if (mftb() & 0x1)
+					hpte_group = ((hash & htab_hash_mask) *
+						      HPTES_PER_GROUP) & ~0x7UL;
+
+				ppc_md.hpte_remove(hpte_group);
+				goto repeat;
+			}
+		}
+		/*
+		 * Hypervisor failure. Restore old pmd and return -1
+		 * similar to __hash_page_*
+		 */
+		if (unlikely(slot == -2)) {
+			*pmdp = __pmd(old_pmd);
+			hash_failure_debug(ea, access, vsid, trap, ssize,
+					   psize, lpsize, old_pmd);
+			return -1;
+		}
+		/*
+		 * large pte is marked busy, so we can be sure
+		 * nobody is looking at hpte_slot_array. hence we can
+		 * safely update this here.
+		 */
+		mark_hpte_slot_valid(hpte_slot_array, index, slot);
+	}
+	/*
+	 * No need to use ldarx/stdcx here
+	 */
+	*pmdp = __pmd(new_pmd & ~_PAGE_BUSY);
+	return 0;
+}
-- 
1.8.1.2

[PATCH -V9 14/20] powerpc: Make linux pagetable walk safe with THP enabled

[Aneesh Kumar K.V]

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

We need to have irqs disabled to handle all the possible parallel update for
linux page table without holding locks.

Events that we are intersted in while walking page tables are
1) Page fault
2) umap
3) THP split
4) THP collapse

A) local_irq_disabled:
------------------------
1) page fault:
A none to valid transition via page fault is not an issue because we
would either see a none or valid. If it is none, we would error out
the page table walk. We may need to use on stack values when checking for
type of page table elements, because if we do

if (!is_hugepd()) {
    if (!pmd_none() {
       if (pmd_bad() {

We could take that bad condition because the pmd got converted to a hugepd
after the !is_hugepd check via a hugetlb fault.

The right way would be to check for pmd_none higher up or use on stack value.

2) A valid to none conversion via unmap:
We can safely walk the upper level table, because we don't remove the the
page table entries until rcu grace period. So even if we followed a
wrong pointer we still have the pointer valid till the grace period.

A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and
 _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent
pte_clear we take _PAGE_BUSY.

3) THP split:
A valid transparent hugepage is converted to nomal page. Before we split we
do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING
So when walking page table we need to check for pmd_trans_splitting and
handle that. The pte returned should also need to be checked for
_PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save
the value of PTE on stack and check for the flag in the local pte value.
If we don't have the value set we can safely operate on the local pte value
and we atomicaly set _PAGE_BUSY.

4) THP collapse:
A normal page gets converted to hugepage. In the collapse path, we
mark the pmd none early (pmdp_clear_flush). With irq disabled, if we
are aleady walking page table we would see the pmd_none and won't continue.
If we see a valid PMD, we should still check for _PAGE_PRESENT before
setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hash_utils_64.c   | 27 ++++++++-------
 arch/powerpc/mm/hugepage-hash64.c |  3 ++
 arch/powerpc/mm/hugetlbpage.c     | 72 +++++++++++++++++++++++++--------------
 arch/powerpc/mm/mem.c             |  4 +++
 4 files changed, 68 insertions(+), 38 deletions(-)

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index aad140b..67b2dbd 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1180,13 +1180,25 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 	pgdir = mm->pgd;
 	if (pgdir == NULL)
 		return;
+
+	/* Get VSID */
+	ssize = user_segment_size(ea);
+	vsid = get_vsid(mm->context.id, ea, ssize);
+	if (!vsid)
+		return;
+	/*
+	 * Hash doesn't like irqs. Walking linux page table with irq disabled
+	 * saves us from holding multiple locks.
+	 */
+	local_irq_save(flags);
+
 	/*
 	 * THP pages use update_mmu_cache_pmd. We don't do
 	 * hash preload there. Hence can ignore THP here
 	 */
 	ptep = find_linux_pte_or_hugepte(pgdir, ea, &shift);
 	if (!ptep)
-		return;
+		goto out_exit;
 
 	BUG_ON(shift);
 #ifdef CONFIG_PPC_64K_PAGES
@@ -1197,18 +1209,9 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 	 * page size demotion here
 	 */
 	if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_NO_CACHE))
-		return;
+		goto out_exit;
 #endif /* CONFIG_PPC_64K_PAGES */
 
-	/* Get VSID */
-	ssize = user_segment_size(ea);
-	vsid = get_vsid(mm->context.id, ea, ssize);
-	if (!vsid)
-		return;
-
-	/* Hash doesn't like irqs */
-	local_irq_save(flags);
-
 	/* Is that local to this CPU ? */
 	if (cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 		local = 1;
@@ -1230,7 +1233,7 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 				   mm->context.user_psize,
 				   mm->context.user_psize,
 				   pte_val(*ptep));
-
+out_exit:
 	local_irq_restore(flags);
 }
 
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index 3712e80..e430766 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -37,6 +37,9 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
 		/* If PMD busy, retry the access */
 		if (unlikely(old_pmd & _PAGE_BUSY))
 			return 0;
+		/* If PMD is trans splitting retry the access */
+		if (unlikely(old_pmd & _PAGE_SPLITTING))
+			return 0;
 		/* If PMD permissions don't match, take page fault */
 		if (unlikely(access & ~old_pmd))
 			return 1;
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 8add580..e9e6882 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -925,12 +925,16 @@ void flush_dcache_icache_hugepage(struct page *page)
  * (2) pointer to next table, as normal; bottom 6 bits == 0
  * (3) leaf pte for huge page, bottom two bits != 00
  * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
+ *
+ * So long as we atomically load page table pointers we are safe against teardown,
+ * we can follow the address down to the the page and take a ref on it.
  */
+
 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
 {
-	pgd_t *pg;
-	pud_t *pu;
-	pmd_t *pm;
+	pgd_t pgd, *pgdp;
+	pud_t pud, *pudp;
+	pmd_t pmd, *pmdp;
 	pte_t *ret_pte;
 	hugepd_t *hpdp = NULL;
 	unsigned pdshift = PGDIR_SHIFT;
@@ -938,34 +942,42 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
 	if (shift)
 		*shift = 0;
 
-	pg = pgdir + pgd_index(ea);
-
+	pgdp = pgdir + pgd_index(ea);
+	pgd  = ACCESS_ONCE(*pgdp);
 	/*
-	 * we should first check for none. That takes care of a
-	 * a parallel hugetlb or THP pagefault moving none entries
-	 * to respective types.
+	 * Always operate on the local stack value. This make sure the
+	 * value don't get updated by a parallel THP split/collapse,
+	 * page fault or a page unmap. The return pte_t * is still not
+	 * stable. So should be checked there for above conditions.
 	 */
-	if (pgd_none(*pg))
+	if (pgd_none(pgd))
 		return NULL;
-	else if (pgd_huge(*pg)) {
-		ret_pte = (pte_t *) pg;
+	else if (pgd_huge(pgd)) {
+		ret_pte = (pte_t *) pgdp;
 		goto out;
-	} else if (is_hugepd(pg))
-		hpdp = (hugepd_t *)pg;
+	} else if (is_hugepd(&pgd))
+		hpdp = (hugepd_t *)&pgd;
 	else {
+		/*
+		 * Even if we end up with an unmap, the pgtable will not
+		 * be freed, because we do an rcu free and here we are
+		 * irq disabled
+		 */
 		pdshift = PUD_SHIFT;
-		pu = pud_offset(pg, ea);
+		pudp = pud_offset(&pgd, ea);
+		pud  = ACCESS_ONCE(*pudp);
 
-		if (pud_none(*pu))
+		if (pud_none(pud))
 			return NULL;
-		else if (pud_huge(*pu)) {
-			ret_pte = (pte_t *) pu;
+		else if (pud_huge(pud)) {
+			ret_pte = (pte_t *) pudp;
 			goto out;
-		} else if (is_hugepd(pu))
-			hpdp = (hugepd_t *)pu;
+		} else if (is_hugepd(&pud))
+			hpdp = (hugepd_t *)&pud;
 		else {
 			pdshift = PMD_SHIFT;
-			pm = pmd_offset(pu, ea);
+			pmdp = pmd_offset(&pud, ea);
+			pmd  = ACCESS_ONCE(*pmdp);
 			/*
 			 * A hugepage collapse is captured by pmd_none, because
 			 * it mark the pmd none and do a hpte invalidate.
@@ -975,16 +987,16 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
 			 * hpte invalidate
 			 *
 			 */
-			if (pmd_none(*pm) || pmd_trans_splitting(*pm))
+			if (pmd_none(pmd) || pmd_trans_splitting(pmd))
 				return NULL;
 
-			if (pmd_huge(*pm) || pmd_large(*pm)) {
-				ret_pte = (pte_t *) pm;
+			if (pmd_huge(pmd) || pmd_large(pmd)) {
+				ret_pte = (pte_t *) pmdp;
 				goto out;
-			} else if (is_hugepd(pm))
-				hpdp = (hugepd_t *)pm;
+			} else if (is_hugepd(&pmd))
+				hpdp = (hugepd_t *)&pmd;
 			else
-				return pte_offset_kernel(pm, ea);
+				return pte_offset_kernel(&pmd, ea);
 		}
 	}
 	if (!hpdp)
@@ -1020,6 +1032,14 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 	if ((pte_val(pte) & mask) != mask)
 		return 0;
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	/*
+	 * check for splitting here
+	 */
+	if (pmd_trans_splitting(pte_pmd(pte)))
+		return 0;
+#endif
+
 	/* hugepages are never "special" */
 	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 0988a26..ccd49f9 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -508,6 +508,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 		      pte_t *ptep)
 {
 #ifdef CONFIG_PPC_STD_MMU
+	/*
+	 * We don't need to worry about _PAGE_PRESENT here because we are
+	 * called with either mm->page_table_lock held or ptl lock held
+	 */
 	unsigned long access = 0, trap;
 
 	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
-- 
1.8.1.2

[PATCH -V9 15/20] powerpc: Prevent gcc to re-read the pagetables

[Aneesh Kumar K.V]

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

GCC is very likely to read the pagetables just once and cache them in
the local stack or in a register, but it is can also decide to re-read
the pagetables. The problem is that the pagetable in those places can
change from under gcc.

With THP/hugetlbfs the pmd (and pgd for hugetlbfs giga pages) can
change under gup_fast. The pages won't be freed untill we finish
gup fast because we have irq disabled and we free these pages via
rcu callback.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/gup.c         | 8 ++++----
 arch/powerpc/mm/hugetlbpage.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index 3d36fd7..4823e4d 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -34,7 +34,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
 
 	ptep = pte_offset_kernel(&pmd, addr);
 	do {
-		pte_t pte = *ptep;
+		pte_t pte = ACCESS_ONCE(*ptep);
 		struct page *page;
 
 		if ((pte_val(pte) & mask) != result)
@@ -63,7 +63,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 
 	pmdp = pmd_offset(&pud, addr);
 	do {
-		pmd_t pmd = *pmdp;
+		pmd_t pmd = ACCESS_ONCE(*pmdp);
 
 		next = pmd_addr_end(addr, end);
 		/*
@@ -102,7 +102,7 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
 
 	pudp = pud_offset(&pgd, addr);
 	do {
-		pud_t pud = *pudp;
+		pud_t pud = ACCESS_ONCE(*pudp);
 
 		next = pud_addr_end(addr, end);
 		if (pud_none(pud))
@@ -165,7 +165,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 
 	pgdp = pgd_offset(mm, addr);
 	do {
-		pgd_t pgd = *pgdp;
+		pgd_t pgd = ACCESS_ONCE(*pgdp);
 
 		pr_devel("  %016lx: normal pgd %p\n", addr,
 			 (void *)pgd_val(pgd));
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index e9e6882..f2f01fd 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -1024,7 +1024,7 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 	if (pte_end < end)
 		end = pte_end;
 
-	pte = *ptep;
+	pte = ACCESS_ONCE(*ptep);
 	mask = _PAGE_PRESENT | _PAGE_USER;
 	if (write)
 		mask |= _PAGE_RW;
-- 
1.8.1.2

[PATCH -V9 16/20] powerpc/THP: Enable THP on PPC64

[Aneesh Kumar K.V]

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

We enable only if the we support 16MB page size.

Reviewed-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgtable-ppc64.h |  3 +--
 arch/powerpc/mm/pgtable_64.c             | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index 69cb52b..d046289 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -429,8 +429,7 @@ static inline int pmd_trans_splitting(pmd_t pmd)
 	return 0;
 }
 
-/* We will enable it in the last patch */
-#define has_transparent_hugepage() 0
+extern int has_transparent_hugepage(void);
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static inline pte_t pmd_pte(pmd_t pmd)
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 2ff92aa..1abf9cd 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -818,4 +818,33 @@ pmd_t pmdp_get_and_clear(struct mm_struct *mm,
 	memset(pgtable, 0, PTE_FRAG_SIZE);
 	return old_pmd;
 }
+
+int has_transparent_hugepage(void)
+{
+	if (!mmu_has_feature(MMU_FTR_16M_PAGE))
+		return 0;
+	/*
+	 * We support THP only if PMD_SIZE is 16MB.
+	 */
+	if (mmu_psize_defs[MMU_PAGE_16M].shift != PMD_SHIFT)
+		return 0;
+	/*
+	 * We need to make sure that we support 16MB hugepage in a segement
+	 * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE
+	 * of 64K.
+	 */
+	/*
+	 * If we have 64K HPTE, we will be using that by default
+	 */
+	if (mmu_psize_defs[MMU_PAGE_64K].shift &&
+	    (mmu_psize_defs[MMU_PAGE_64K].penc[MMU_PAGE_16M] == -1))
+		return 0;
+	/*
+	 * Ok we only have 4K HPTE
+	 */
+	if (mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M] == -1)
+		return 0;
+
+	return 1;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-- 
1.8.1.2

[PATCH -V9 17/20] powerpc: Optimize hugepage invalidate

[Aneesh Kumar K.V]

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

Hugepage invalidate involves invalidating multiple hpte entries.
Optimize the operation using H_BULK_REMOVE on lpar platforms.
On native, reduce the number of tlb flush.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/machdep.h    |   3 +
 arch/powerpc/mm/hash_native_64.c      |  74 +++++++++++++++++++++
 arch/powerpc/mm/pgtable_64.c          |  12 +++-
 arch/powerpc/platforms/pseries/lpar.c | 122 ++++++++++++++++++++++++++++++++--
 4 files changed, 202 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 92386fc..9c5a3ad 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -57,6 +57,9 @@ struct machdep_calls {
 	void            (*hpte_removebolted)(unsigned long ea,
 					     int psize, int ssize);
 	void		(*flush_hash_range)(unsigned long number, int local);
+	void		(*hugepage_invalidate)(struct mm_struct *mm,
+					       unsigned char *hpte_slot_array,
+					       unsigned long addr, int psize);
 
 	/* special for kexec, to be called in real mode, linear mapping is
 	 * destroyed as well */
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 6a2aead..4a92f14 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -455,6 +455,79 @@ static void native_hpte_invalidate(unsigned long slot, unsigned long vpn,
 	local_irq_restore(flags);
 }
 
+static void native_hugepage_invalidate(struct mm_struct *mm,
+				       unsigned char *hpte_slot_array,
+				       unsigned long addr, int psize)
+{
+	int ssize = 0, i;
+	int lock_tlbie;
+	struct hash_pte *hptep;
+	int actual_psize = MMU_PAGE_16M;
+	unsigned int max_hpte_count, valid;
+	unsigned long flags, s_addr = addr;
+	unsigned long hpte_v, want_v, shift;
+	unsigned long hidx, vpn = 0, vsid, hash, slot;
+
+	shift = mmu_psize_defs[psize].shift;
+	max_hpte_count = HPAGE_PMD_SIZE >> shift;
+
+	local_irq_save(flags);
+	for (i = 0; i < max_hpte_count; i++) {
+		valid = hpte_valid(hpte_slot_array, i);
+		if (!valid)
+			continue;
+		hidx =  hpte_hash_index(hpte_slot_array, i);
+
+		/* get the vpn */
+		addr = s_addr + (i * (1ul << shift));
+		if (!is_kernel_addr(addr)) {
+			ssize = user_segment_size(addr);
+			vsid = get_vsid(mm->context.id, addr, ssize);
+			WARN_ON(vsid == 0);
+		} else {
+			vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+			ssize = mmu_kernel_ssize;
+		}
+
+		vpn = hpt_vpn(addr, vsid, ssize);
+		hash = hpt_hash(vpn, shift, ssize);
+		if (hidx & _PTEIDX_SECONDARY)
+			hash = ~hash;
+
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += hidx & _PTEIDX_GROUP_IX;
+
+		hptep = htab_address + slot;
+		want_v = hpte_encode_avpn(vpn, psize, ssize);
+		native_lock_hpte(hptep);
+		hpte_v = hptep->v;
+
+		/* Even if we miss, we need to invalidate the TLB */
+		if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
+			native_unlock_hpte(hptep);
+		else
+			/* Invalidate the hpte. NOTE: this also unlocks it */
+			hptep->v = 0;
+	}
+	/*
+	 * Since this is a hugepage, we just need a single tlbie.
+	 * use the last vpn.
+	 */
+	lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
+	if (lock_tlbie)
+		raw_spin_lock(&native_tlbie_lock);
+
+	asm volatile("ptesync":::"memory");
+	__tlbie(vpn, psize, actual_psize, ssize);
+	asm volatile("eieio; tlbsync; ptesync":::"memory");
+
+	if (lock_tlbie)
+		raw_spin_unlock(&native_tlbie_lock);
+
+	local_irq_restore(flags);
+}
+
+
 static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
 			int *psize, int *apsize, int *ssize, unsigned long *vpn)
 {
@@ -658,4 +731,5 @@ void __init hpte_init_native(void)
 	ppc_md.hpte_remove	= native_hpte_remove;
 	ppc_md.hpte_clear_all	= native_hpte_clear;
 	ppc_md.flush_hash_range = native_flush_hash_range;
+	ppc_md.hugepage_invalidate   = native_hugepage_invalidate;
 }
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 1abf9cd..8dd7c83 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -692,6 +692,7 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
 {
 	int ssize, i;
 	unsigned long s_addr;
+	int max_hpte_count;
 	unsigned int psize, valid;
 	unsigned char *hpte_slot_array;
 	unsigned long hidx, vpn, vsid, hash, shift, slot;
@@ -715,9 +716,16 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
 
 	/* get the base page size */
 	psize = get_slice_psize(mm, s_addr);
-	shift = mmu_psize_defs[psize].shift;
 
-	for (i = 0; i < (HPAGE_PMD_SIZE >> shift); i++) {
+	if (ppc_md.hugepage_invalidate)
+		return ppc_md.hugepage_invalidate(mm, hpte_slot_array,
+						  s_addr, psize);
+	/*
+	 * No bluk hpte removal support, invalidate each entry
+	 */
+	shift = mmu_psize_defs[psize].shift;
+	max_hpte_count = HPAGE_PMD_SIZE >> shift;
+	for (i = 0; i < max_hpte_count; i++) {
 		/*
 		 * 8 bits per each hpte entries
 		 * 000| [ secondary group (one bit) | hidx (3 bits) | valid bit]
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 6d62072..aa098c7 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -45,6 +45,13 @@
 #include "plpar_wrappers.h"
 #include "pseries.h"
 
+/* Flag bits for H_BULK_REMOVE */
+#define HBR_REQUEST	0x4000000000000000UL
+#define HBR_RESPONSE	0x8000000000000000UL
+#define HBR_END		0xc000000000000000UL
+#define HBR_AVPN	0x0200000000000000UL
+#define HBR_ANDCOND	0x0100000000000000UL
+
 
 /* in hvCall.S */
 EXPORT_SYMBOL(plpar_hcall);
@@ -345,6 +352,113 @@ static void pSeries_lpar_hpte_invalidate(unsigned long slot, unsigned long vpn,
 	BUG_ON(lpar_rc != H_SUCCESS);
 }
 
+/*
+ * Limit iterations holding pSeries_lpar_tlbie_lock to 3. We also need
+ * to make sure that we avoid bouncing the hypervisor tlbie lock.
+ */
+#define PPC64_HUGE_HPTE_BATCH 12
+
+static void __pSeries_lpar_hugepage_invalidate(unsigned long *slot,
+					     unsigned long *vpn, int count,
+					     int psize, int ssize)
+{
+	unsigned long param[8];
+	int i = 0, pix = 0, rc;
+	unsigned long flags = 0;
+	int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
+
+	if (lock_tlbie)
+		spin_lock_irqsave(&pSeries_lpar_tlbie_lock, flags);
+
+	for (i = 0; i < count; i++) {
+
+		if (!firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
+			pSeries_lpar_hpte_invalidate(slot[i], vpn[i], psize,
+						     ssize, 0);
+		} else {
+			param[pix] = HBR_REQUEST | HBR_AVPN | slot[i];
+			param[pix+1] = hpte_encode_avpn(vpn[i], psize, ssize);
+			pix += 2;
+			if (pix == 8) {
+				rc = plpar_hcall9(H_BULK_REMOVE, param,
+						  param[0], param[1], param[2],
+						  param[3], param[4], param[5],
+						  param[6], param[7]);
+				BUG_ON(rc != H_SUCCESS);
+				pix = 0;
+			}
+		}
+	}
+	if (pix) {
+		param[pix] = HBR_END;
+		rc = plpar_hcall9(H_BULK_REMOVE, param, param[0], param[1],
+				  param[2], param[3], param[4], param[5],
+				  param[6], param[7]);
+		BUG_ON(rc != H_SUCCESS);
+	}
+
+	if (lock_tlbie)
+		spin_unlock_irqrestore(&pSeries_lpar_tlbie_lock, flags);
+}
+
+static void pSeries_lpar_hugepage_invalidate(struct mm_struct *mm,
+				       unsigned char *hpte_slot_array,
+				       unsigned long addr, int psize)
+{
+	int ssize = 0, i, index = 0;
+	unsigned long s_addr = addr;
+	unsigned int max_hpte_count, valid;
+	unsigned long vpn_array[PPC64_HUGE_HPTE_BATCH];
+	unsigned long slot_array[PPC64_HUGE_HPTE_BATCH];
+	unsigned long shift, hidx, vpn = 0, vsid, hash, slot;
+
+	shift = mmu_psize_defs[psize].shift;
+	max_hpte_count = HPAGE_PMD_SIZE >> shift;
+
+	for (i = 0; i < max_hpte_count; i++) {
+		valid = hpte_valid(hpte_slot_array, i);
+		if (!valid)
+			continue;
+		hidx =  hpte_hash_index(hpte_slot_array, i);
+
+		/* get the vpn */
+		addr = s_addr + (i * (1ul << shift));
+		if (!is_kernel_addr(addr)) {
+			ssize = user_segment_size(addr);
+			vsid = get_vsid(mm->context.id, addr, ssize);
+			WARN_ON(vsid == 0);
+		} else {
+			vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+			ssize = mmu_kernel_ssize;
+		}
+
+		vpn = hpt_vpn(addr, vsid, ssize);
+		hash = hpt_hash(vpn, shift, ssize);
+		if (hidx & _PTEIDX_SECONDARY)
+			hash = ~hash;
+
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += hidx & _PTEIDX_GROUP_IX;
+
+		slot_array[index] = slot;
+		vpn_array[index] = vpn;
+		if (index == PPC64_HUGE_HPTE_BATCH - 1) {
+			/*
+			 * Now do a bluk invalidate
+			 */
+			__pSeries_lpar_hugepage_invalidate(slot_array,
+							   vpn_array,
+							   PPC64_HUGE_HPTE_BATCH,
+							   psize, ssize);
+			index = 0;
+		} else
+			index++;
+	}
+	if (index)
+		__pSeries_lpar_hugepage_invalidate(slot_array, vpn_array,
+						   index, psize, ssize);
+}
+
 static void pSeries_lpar_hpte_removebolted(unsigned long ea,
 					   int psize, int ssize)
 {
@@ -360,13 +474,6 @@ static void pSeries_lpar_hpte_removebolted(unsigned long ea,
 	pSeries_lpar_hpte_invalidate(slot, vpn, psize, ssize, 0);
 }
 
-/* Flag bits for H_BULK_REMOVE */
-#define HBR_REQUEST	0x4000000000000000UL
-#define HBR_RESPONSE	0x8000000000000000UL
-#define HBR_END		0xc000000000000000UL
-#define HBR_AVPN	0x0200000000000000UL
-#define HBR_ANDCOND	0x0100000000000000UL
-
 /*
  * Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
  * lock.
@@ -452,6 +559,7 @@ void __init hpte_init_lpar(void)
 	ppc_md.hpte_removebolted = pSeries_lpar_hpte_removebolted;
 	ppc_md.flush_hash_range	= pSeries_lpar_flush_hash_range;
 	ppc_md.hpte_clear_all   = pSeries_lpar_hptab_clear;
+	ppc_md.hugepage_invalidate = pSeries_lpar_hugepage_invalidate;
 }
 
 #ifdef CONFIG_PPC_SMLPAR
-- 
1.8.1.2

[PATCH -V9 18/20] powerpc: disable assert_pte_locked for collapse_huge_page

[Aneesh Kumar K.V]

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

With THP we set pmd to none, before we do pte_clear. Hence we can't
walk page table to get the pte lock ptr and verify whether it is locked.
THP do take pte lock before calling pte_clear. So we don't change the locking
rules here. It is that we can't use page table walking to check whether
pte locks are held with THP.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/pgtable.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 214130a..edda589 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -235,6 +235,14 @@ void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
 	pud = pud_offset(pgd, addr);
 	BUG_ON(pud_none(*pud));
 	pmd = pmd_offset(pud, addr);
+	/*
+	 * khugepaged to collapse normal pages to hugepage, first set
+	 * pmd to none to force page fault/gup to take mmap_sem. After
+	 * pmd is set to none, we do a pte_clear which does this assertion
+	 * so if we find pmd none, return.
+	 */
+	if (pmd_none(*pmd))
+		return;
 	BUG_ON(!pmd_present(*pmd));
 	assert_spin_locked(pte_lockptr(mm, pmd));
 }
-- 
1.8.1.2

[PATCH -V9 19/20] powerpc: use smp_rmb when looking at deposisted pgtable to store hash index

[Aneesh Kumar K.V]

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

We need to use smb_rmb when looking at hpte slot array. Otherwise we could
reorder the hpte_slot array load bfore even we marked the pmd trans huge.
Related smb_wmb()s is done in pgtable_trans_huge_deposit when we deposit
a pgtable.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgtable-ppc64.h | 15 +++++++++++++++
 arch/powerpc/mm/hugepage-hash64.c        |  6 +-----
 arch/powerpc/mm/pgtable_64.c             |  6 +-----
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index d046289..46db094 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -10,6 +10,7 @@
 #else
 #include <asm/pgtable-ppc64-4k.h>
 #endif
+#include <asm/barrier.h>
 
 #define FIRST_USER_ADDRESS	0
 
@@ -393,6 +394,20 @@ static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array,
 	hpte_slot_array[index] = hidx << 4 | 0x1 << 3;
 }
 
+static inline char *get_hpte_slot_array(pmd_t *pmdp)
+{
+	/*
+	 * The hpte hindex is stored in the pgtable whose address is in the
+	 * second half of the PMD
+	 *
+	 * Order this load with the test for pmd_trans_huge in the caller
+	 */
+	smp_rmb();
+	return *(char **)(pmdp + PTRS_PER_PMD);
+
+
+}
+
 extern void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
 				   pmd_t *pmdp);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index e430766..c3ba3d5 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -84,11 +84,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
 
 	vpn = hpt_vpn(ea, vsid, ssize);
 	hash = hpt_hash(vpn, shift, ssize);
-	/*
-	 * The hpte hindex are stored in the pgtable whose address is in the
-	 * second half of the PMD
-	 */
-	hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+	hpte_slot_array = get_hpte_slot_array(pmdp);
 
 	valid = hpte_valid(hpte_slot_array, index);
 	if (valid) {
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 8dd7c83..19d6734 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -701,11 +701,7 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
 	 * Flush all the hptes mapping this hugepage
 	 */
 	s_addr = addr & HPAGE_PMD_MASK;
-	/*
-	 * The hpte hindex are stored in the pgtable whose address is in the
-	 * second half of the PMD
-	 */
-	hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
+	hpte_slot_array = get_hpte_slot_array(pmdp);
 	/*
 	 * IF we try to do a HUGE PTE update after a withdraw is done.
 	 * we will find the below NULL. This happens when we do
-- 
1.8.1.2

[PATCH -V9 20/20] powerpc: split hugepage when using subpage protection

[Aneesh Kumar K.V]

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

We find all the overlapping vma and mark them such that we don't allocate
hugepage in that range. Also we split existing huge page so that the
normal page hash can be invalidated and new page faulted in with new
protection bits.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/subpage-prot.c | 48 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/arch/powerpc/mm/subpage-prot.c b/arch/powerpc/mm/subpage-prot.c
index 7c415dd..aa74acb 100644
--- a/arch/powerpc/mm/subpage-prot.c
+++ b/arch/powerpc/mm/subpage-prot.c
@@ -130,6 +130,53 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len)
 	up_write(&mm->mmap_sem);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
+				  unsigned long end, struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->private;
+	split_huge_page_pmd(vma, addr, pmd);
+	return 0;
+}
+
+static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
+				    unsigned long len)
+{
+	struct vm_area_struct *vma;
+	struct mm_walk subpage_proto_walk = {
+		.mm = mm,
+		.pmd_entry = subpage_walk_pmd_entry,
+	};
+
+	/*
+	 * We don't try too hard, we just mark all the vma in that range
+	 * VM_NOHUGEPAGE and split them.
+	 */
+	vma = find_vma(mm, addr);
+	/*
+	 * If the range is in unmapped range, just return
+	 */
+	if (vma && ((addr + len) <= vma->vm_start))
+		return;
+
+	while (vma) {
+		if (vma->vm_start >= (addr + len))
+			break;
+		vma->vm_flags |= VM_NOHUGEPAGE;
+		subpage_proto_walk.private = vma;
+		walk_page_range(vma->vm_start, vma->vm_end,
+				&subpage_proto_walk);
+		vma = vma->vm_next;
+	}
+}
+#else
+static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
+				    unsigned long len)
+{
+	return;
+}
+#endif
+
 /*
  * Copy in a subpage protection map for an address range.
  * The map has 2 bits per 4k subpage, so 32 bits per 64k page.
@@ -168,6 +215,7 @@ long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
 		return -EFAULT;
 
 	down_write(&mm->mmap_sem);
+	subpage_mark_vma_nohuge(mm, addr, len);
 	for (limit = addr + len; addr < limit; addr = next) {
 		next = pmd_addr_end(addr, limit);
 		err = -ENOMEM;
-- 
1.8.1.2