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Subject[RFC v6 33/62] powerpc: introduce get_pte_pkey() helper
Date
get_pte_pkey() helper returns the pkey associated with
a address corresponding to a given mm_struct.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 +++++
arch/powerpc/mm/hash_utils_64.c | 25 +++++++++++++++++++++++++
2 files changed, 30 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..6bc8e91 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1573,6 +1573,31 @@ 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 (!mm || !mm->pgd)
+ return 0;
+
+ local_irq_save(flags);
+ ptep = find_linux_pte_or_hugepte(mm->pgd, address,
+ NULL, NULL);
+ if (ptep)
+ pkey = pte_to_pkey_bits(pte_val(READ_ONCE(*ptep)));
+ local_irq_restore(flags);
+
+ return pkey;
+}
+#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static inline void tm_flush_hash_page(int local)
{
--
1.7.1
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