helper function that checks if the read/write/execute is allowed
on the pte.
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +
arch/powerpc/include/asm/pkeys.h | 9 +++++++
arch/powerpc/mm/pkeys.c | 31 ++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index d9c87c4..aad205c 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -474,6 +474,8 @@ static inline void write_uamor(u64 value)
mtspr(SPRN_UAMOR, value);
}
+extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute);
+
#else /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
static inline u64 read_amr(void)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 6477b87..01f2bfc 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -31,6 +31,15 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
((pteflags & H_PAGE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL));
}
+static inline u16 pte_to_pkey_bits(u64 pteflags)
+{
+ return (((pteflags & H_PAGE_PKEY_BIT0) ? 0x10 : 0x0UL) |
+ ((pteflags & H_PAGE_PKEY_BIT1) ? 0x8 : 0x0UL) |
+ ((pteflags & H_PAGE_PKEY_BIT2) ? 0x4 : 0x0UL) |
+ ((pteflags & H_PAGE_PKEY_BIT3) ? 0x2 : 0x0UL) |
+ ((pteflags & H_PAGE_PKEY_BIT4) ? 0x1 : 0x0UL));
+}
+
static inline int vma_pkey(struct vm_area_struct *vma)
{
return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index c60a045..044a17d 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -170,3 +170,34 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
*/
return vma_pkey(vma);
}
+
+static bool pkey_access_permitted(int pkey, bool write, bool execute)
+{
+ int pkey_shift;
+ u64 amr;
+
+ if (!pkey)
+ return true;
+
+ pkey_shift = pkeyshift(pkey);
+ if (!(read_uamor() & (0x3UL << pkey_shift)))
+ return true;
+
+ if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift)))
+ return true;
+
+ if (!write) {
+ amr = read_amr();
+ if (!(amr & (AMR_AD_BIT << pkey_shift)))
+ return true;
+ }
+
+ amr = read_amr(); /* delay reading amr uptil absolutely needed */
+ return (write && !(amr & (AMR_WD_BIT << pkey_shift)));
+}
+
+bool arch_pte_access_permitted(u64 pte, bool write, bool execute)
+{
+ return pkey_access_permitted(pte_to_pkey_bits(pte),
+ write, execute);
+}
--
1.7.1
--
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