Re: [PATCH V2 1/4] powerpc/mm: Fix crashes with PUD level hugetlb config

To support memory keys, we moved the hash pte slot information to the second
half of the page table. This was ok with PTE entries at level 4 and level 3.
We already allocate larger page table pages at those level to accomodate extra
details. For level 4 we already have the extra space which was used to track
4k hash page table entry details and at pmd level the extra space was allocated
to track the THP details.

With hugetlbfs PTE, we used this extra space at the PMD level to store the
slot details. But we also support hugetlbfs PTE at PUD leve and PUD level page
didn't allocate extra space. This resulted in memory corruption.

Fix this by allocating extra space at PUD level when HUGETLB is enabled. We
may need further changes to allocate larger space at PMD level when we enable
HUGETLB. That will be done in next patch.

Fixes:bf9a95f9a6481bc6e(" powerpc: Free up four 64K PTE bits in 64K backed HPTE pages")

Signed-off-by: Aneesh Kumar K.V <redacted>
---
 arch/powerpc/include/asm/book3s/32/pgtable.h  |  1 +
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  5 +++++
 arch/powerpc/include/asm/book3s/64/hash.h     | 10 ++++++++++
 arch/powerpc/include/asm/book3s/64/pgalloc.h  |  6 +++---
 arch/powerpc/include/asm/book3s/64/pgtable.h  |  2 ++
 arch/powerpc/include/asm/nohash/32/pgtable.h  |  1 +
 arch/powerpc/include/asm/nohash/64/pgtable.h  |  1 +
 arch/powerpc/mm/hash_utils_64.c               |  1 +
 arch/powerpc/mm/init-common.c                 |  4 ++--
 arch/powerpc/mm/pgtable-radix.c               |  1 +
 arch/powerpc/mm/pgtable_64.c                  |  2 ++
 11 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 30a155c0a6b0..c615abdce119 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h

@@ -16,6 +16,7 @@
 #define PGD_INDEX_SIZE	(32 - PGDIR_SHIFT)

 #define PMD_CACHE_INDEX	PMD_INDEX_SIZE
+#define PUD_CACHE_INDEX	PUD_INDEX_SIZE

 #ifndef __ASSEMBLY__
 #define PTE_TABLE_SIZE	(sizeof(pte_t) << PTE_INDEX_SIZE)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 338b7da468ce..c08b3b032ec0 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h

@@ -146,7 +146,12 @@ static inline int hash__remap_4k_pfn(struct vm_area_struct *vma, unsigned long a
 #else
 #define H_PMD_TABLE_SIZE	(sizeof(pmd_t) << PMD_INDEX_SIZE)
 #endif
+#ifdef CONFIG_HUGETLB_PAGE
+#define H_PUD_TABLE_SIZE	((sizeof(pud_t) << PUD_INDEX_SIZE) +	\
+				 (sizeof(unsigned long) << PUD_INDEX_SIZE))
+#else
 #define H_PUD_TABLE_SIZE	(sizeof(pud_t) << PUD_INDEX_SIZE)
+#endif
 #define H_PGD_TABLE_SIZE	(sizeof(pgd_t) << PGD_INDEX_SIZE)

 #ifdef CONFIG_TRANSPARENT_HUGEPAGE

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 0920eff731b3..234f141fb151 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h

@@ -32,6 +32,16 @@
 #else
 #define H_PMD_CACHE_INDEX	H_PMD_INDEX_SIZE
 #endif
+/*
+ * We not store the slot details in the second half of page table.