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Subject[PATCH v9 20/51] powerpc: introduce get_mm_addr_key() helper
Date
get_mm_addr_key() helper returns the pkey associated with
an address corresponding to a given mm_struct.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/include/asm/mmu.h | 9 +++++++++
arch/powerpc/mm/hash_utils_64.c | 24 ++++++++++++++++++++++++
2 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 6364f5c..bb38312 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -260,6 +260,15 @@ static inline bool early_radix_enabled(void)
}
#endif

+#ifdef CONFIG_PPC_MEM_KEYS
+extern u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address);
+#else
+static inline u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address)
+{
+ return 0;
+}
+#endif /* CONFIG_PPC_MEM_KEYS */
+
#endif /* !__ASSEMBLY__ */

/* The kernel use the constants below to index in the page sizes array.
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index ddfc673..0108d12 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1575,6 +1575,30 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
local_irq_restore(flags);
}

+#ifdef CONFIG_PPC_MEM_KEYS
+/*
+ * Return the protection key associated with the given address and the
+ * mm_struct.
+ */
+u16 get_mm_addr_key(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(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_PPC_MEM_KEYS */
+
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static inline void tm_flush_hash_page(int local)
{
--
1.7.1
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