x86/mm: Factor out LDT init from context init

[cascardo/linux.git] / arch / x86 / include / asm / mmu_context.h

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index bfd9b2a..8428002 100644 (file)
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -52,15 +52,15 @@ struct ldt_struct {
 /*
  * Used for LDT copy/destruction.
  */
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
-void destroy_context(struct mm_struct *mm);
+int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm);
+void destroy_context_ldt(struct mm_struct *mm);
 #else  /* CONFIG_MODIFY_LDT_SYSCALL */
-static inline int init_new_context(struct task_struct *tsk,
-                                  struct mm_struct *mm)
+static inline int init_new_context_ldt(struct task_struct *tsk,
+                                      struct mm_struct *mm)
 {
        return 0;
 }
-static inline void destroy_context(struct mm_struct *mm) {}
+static inline void destroy_context_ldt(struct mm_struct *mm) {}
 #endif
 
 static inline void load_mm_ldt(struct mm_struct *mm)
@@ -104,6 +104,17 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 #endif
 }
 
+static inline int init_new_context(struct task_struct *tsk,
+                                  struct mm_struct *mm)
+{
+       init_new_context_ldt(tsk, mm);
+       return 0;
+}
+static inline void destroy_context(struct mm_struct *mm)
+{
+       destroy_context_ldt(mm);
+}
+
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
                             struct task_struct *tsk)
 {
@@ -275,4 +286,68 @@ static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
                mpx_notify_unmap(mm, vma, start, end);
 }
 
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+       u16 pkey = 0;
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+       unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
+                                     VM_PKEY_BIT2 | VM_PKEY_BIT3;
+       pkey = (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
+#endif
+       return pkey;
+}
+
+static inline bool __pkru_allows_pkey(u16 pkey, bool write)
+{
+       u32 pkru = read_pkru();
+
+       if (!__pkru_allows_read(pkru, pkey))
+               return false;
+       if (write && !__pkru_allows_write(pkru, pkey))
+               return false;
+
+       return true;
+}
+
+/*
+ * We only want to enforce protection keys on the current process
+ * because we effectively have no access to PKRU for other
+ * processes or any way to tell *which * PKRU 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;
+       /*
+        * Should PKRU be enforced on the access to this VMA?  If
+        * the VMA is from another process, then PKRU has no
+        * relevance and should not be enforced.
+        */
+       if (current->mm != vma->vm_mm)
+               return true;
+
+       return false;
+}
+
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+               bool write, bool execute, bool foreign)
+{
+       /* pkeys never affect instruction fetches */
+       if (execute)
+               return true;
+       /* allow access if the VMA is not one from this process */
+       if (foreign || vma_is_foreign(vma))
+               return true;
+       return __pkru_allows_pkey(vma_pkey(vma), write);
+}
+
+static inline bool arch_pte_access_permitted(pte_t pte, bool write)
+{
+       return __pkru_allows_pkey(pte_flags_pkey(pte_flags(pte)), write);
+}
+
 #endif /* _ASM_X86_MMU_CONTEXT_H */