Merge branch 'userns-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index b32f32b..c32318d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4642,9 +4642,9 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-int follow_pte(struct mm_struct *mm, unsigned long address,
-              struct mmu_notifier_range *range, pte_t **ptepp, pmd_t **pmdpp,
-              spinlock_t **ptlp)
+int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
+                         struct mmu_notifier_range *range, pte_t **ptepp,
+                         pmd_t **pmdpp, spinlock_t **ptlp)
 {
        pgd_t *pgd;
        p4d_t *p4d;
@@ -4709,6 +4709,34 @@ out:
        return -EINVAL;
 }
 
+/**
+ * follow_pte - look up PTE at a user virtual address
+ * @mm: the mm_struct of the target address space
+ * @address: user virtual address
+ * @ptepp: location to store found PTE
+ * @ptlp: location to store the lock for the PTE
+ *
+ * On a successful return, the pointer to the PTE is stored in @ptepp;
+ * the corresponding lock is taken and its location is stored in @ptlp.
+ * The contents of the PTE are only stable until @ptlp is released;
+ * any further use, if any, must be protected against invalidation
+ * with MMU notifiers.
+ *
+ * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore
+ * should be taken for read.
+ *
+ * KVM uses this function.  While it is arguably less bad than ``follow_pfn``,
+ * it is not a good general-purpose API.
+ *
+ * Return: zero on success, -ve otherwise.
+ */
+int follow_pte(struct mm_struct *mm, unsigned long address,
+              pte_t **ptepp, spinlock_t **ptlp)
+{
+       return follow_invalidate_pte(mm, address, NULL, ptepp, NULL, ptlp);
+}
+EXPORT_SYMBOL_GPL(follow_pte);
+
 /**
  * follow_pfn - look up PFN at a user virtual address
  * @vma: memory mapping
@@ -4717,6 +4745,9 @@ out:
  *
  * Only IO mappings and raw PFN mappings are allowed.
  *
+ * This function does not allow the caller to read the permissions
+ * of the PTE.  Do not use it.
+ *
  * Return: zero and the pfn at @pfn on success, -ve otherwise.
  */
 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
@@ -4729,7 +4760,7 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address,
        if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
                return ret;
 
-       ret = follow_pte(vma->vm_mm, address, NULL, &ptep, NULL, &ptl);
+       ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
        if (ret)
                return ret;
        *pfn = pte_pfn(*ptep);
@@ -4750,7 +4781,7 @@ int follow_phys(struct vm_area_struct *vma,
        if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
                goto out;
 
-       if (follow_pte(vma->vm_mm, address, NULL, &ptep, NULL, &ptl))
+       if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
                goto out;
        pte = *ptep;