This patch provides the implementation for
arch_vma_access_permitted(). Returns true if the
requested access is allowed by pkey associated with the
vma.
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
---
arch/powerpc/include/asm/mmu_context.h | 5 +++-
arch/powerpc/mm/pkeys.c | 34 ++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 209f127..cd2bd73 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -186,6 +186,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm,
{
}
+#ifdef CONFIG_PPC_MEM_KEYS
+bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
+ bool execute, bool foreign);
+#else /* CONFIG_PPC_MEM_KEYS */
static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
bool write, bool execute, bool foreign)
{
@@ -193,7 +197,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
return true;
}
-#ifndef CONFIG_PPC_MEM_KEYS
#define pkey_mm_init(mm)
#define thread_pkey_regs_save(thread)
#define thread_pkey_regs_restore(new_thread, old_thread)
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 0e044ea..0701aa3 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -390,3 +390,37 @@ bool arch_pte_access_permitted(u64 pte, bool write, bool execute)
return pkey_access_permitted(pte_to_pkey_bits(pte), write, execute);
}
+
+/*
+ * We only want to enforce protection keys on the current thread because we
+ * effectively have no access to AMR/IAMR for other threads or any way to tell
+ * which AMR/IAMR in a threaded process we could use.
+ *
+ * So do not enforce things if the VMA is not from the current mm, or if we are
+ * in a kernel thread.
+ */
+static inline bool vma_is_foreign(struct vm_area_struct *vma)
+{
+ if (!current->mm)
+ return true;
+
+ /* if it is not our ->mm, it has to be foreign */
+ if (current->mm != vma->vm_mm)
+ return true;
+
+ return false;
+}
+
+bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
+ bool execute, bool foreign)
+{
+ if (static_branch_likely(&pkey_disabled))
+ return true;
+ /*
+ * Do not enforce our key-permissions on a foreign vma.
+ */
+ if (foreign || vma_is_foreign(vma))
+ return true;
+
+ return pkey_access_permitted(vma_pkey(vma), write, execute);
+}
--
1.7.1
