KVM: Fix msr trace

[safe/jmp/linux-2.6] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index 02c09f3..ee22989 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1043,6 +1043,46 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 }
 EXPORT_SYMBOL(do_mmap_pgoff);
 
+SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
+               unsigned long, prot, unsigned long, flags,
+               unsigned long, fd, unsigned long, pgoff)
+{
+       struct file *file = NULL;
+       unsigned long retval = -EBADF;
+
+       if (!(flags & MAP_ANONYMOUS)) {
+               if (unlikely(flags & MAP_HUGETLB))
+                       return -EINVAL;
+               file = fget(fd);
+               if (!file)
+                       goto out;
+       } else if (flags & MAP_HUGETLB) {
+               struct user_struct *user = NULL;
+               /*
+                * VM_NORESERVE is used because the reservations will be
+                * taken when vm_ops->mmap() is called
+                * A dummy user value is used because we are not locking
+                * memory so no accounting is necessary
+                */
+               len = ALIGN(len, huge_page_size(&default_hstate));
+               file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
+                                               &user, HUGETLB_ANONHUGE_INODE);
+               if (IS_ERR(file))
+                       return PTR_ERR(file);
+       }
+
+       flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+
+       down_write(&current->mm->mmap_sem);
+       retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+       up_write(&current->mm->mmap_sem);
+
+       if (file)
+               fput(file);
+out:
+       return retval;
+}
+
 /*
  * Some shared mappigns will want the pages marked read-only
  * to track write events. If so, we'll downgrade vm_page_prot
@@ -1198,8 +1238,20 @@ munmap_back:
                        goto free_vma;
        }
 
-       if (vma_wants_writenotify(vma))
+       if (vma_wants_writenotify(vma)) {
+               pgprot_t pprot = vma->vm_page_prot;
+
+               /* Can vma->vm_page_prot have changed??
+                *
+                * Answer: Yes, drivers may have changed it in their
+                *         f_op->mmap method.
+                *
+                * Ensures that vmas marked as uncached stay that way.
+                */
                vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
+               if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
+                       vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+       }
 
        vma_link(mm, vma, prev, rb_link, rb_parent);
        file = vma->vm_file;