Re: [RFC v5 31/38] powerpc: introduce get_pte_pkey() helper

get_pte_pkey() helper returns the pkey associated with
a address corresponding to a given mm_struct.

Signed-off-by: Ram Pai <redacted>
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |    5 ++++
 arch/powerpc/mm/hash_utils_64.c               |   28 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index f7a6ed3..369f9ff 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h

@@ -450,6 +450,11 @@ 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, unsigned long flags,
 		     int ssize, unsigned int shift, unsigned int mmu_psize);
+
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+u16 get_pte_pkey(struct mm_struct *mm, unsigned long address);
+#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 extern int __hash_page_thp(unsigned long ea, unsigned long access,
 			   unsigned long vsid, pmd_t *pmdp, unsigned long trap,

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 1e74529..591990c 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c

@@ -1573,6 +1573,34 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 	local_irq_restore(flags);
 }
 
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+/*
+ * return the protection key associated with the given address
+ * and the mm_struct.
+ */
+u16 get_pte_pkey(struct mm_struct *mm, unsigned long address)
+{
+	pte_t *ptep;
+	u16 pkey = 0;
+	unsigned long flags;
+
+	if (REGION_ID(address) == VMALLOC_REGION_ID)
+		mm = &init_mm;