KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks

[linux.git] / init / do_mounts.c

diff --git a/init/do_mounts.c b/init/do_mounts.c
index af9cda887a23f32d64b989ced85f8ca2928b0950..0ae9cc22f2ae255c55337812b121a9a2d2eec9ca 100644 (file)
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -387,12 +387,27 @@ static void __init get_fs_names(char *page)
        *s = '\0';
 }
 
-static int __init do_mount_root(char *name, char *fs, int flags, void *data)
+static int __init do_mount_root(const char *name, const char *fs,
+                                const int flags, const void *data)
 {
        struct super_block *s;
-       int err = ksys_mount(name, "/root", fs, flags, data);
-       if (err)
-               return err;
+       struct page *p = NULL;
+       char *data_page = NULL;
+       int ret;
+
+       if (data) {
+               /* do_mount() requires a full page as fifth argument */
+               p = alloc_page(GFP_KERNEL);
+               if (!p)
+                       return -ENOMEM;
+               data_page = page_address(p);
+               /* zero-pad. do_mount() will make sure it's terminated */
+               strncpy(data_page, data, PAGE_SIZE);
+       }
+
+       ret = do_mount(name, "/root", fs, flags, data_page);
+       if (ret)
+               goto out;
 
        ksys_chdir("/root");
        s = current->fs->pwd.dentry->d_sb;
@@ -402,7 +417,11 @@ static int __init do_mount_root(char *name, char *fs, int flags, void *data)
               s->s_type->name,
               sb_rdonly(s) ? " readonly" : "",
               MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
-       return 0;
+
+out:
+       if (p)
+               put_page(p);
+       return ret;
 }
 
 void __init mount_block_root(char *name, int flags)
@@ -670,8 +689,8 @@ void __init prepare_namespace(void)
 
        mount_root();
 out:
-       devtmpfs_mount("dev");
-       ksys_mount(".", "/", NULL, MS_MOVE, NULL);
+       devtmpfs_mount();
+       do_mount(".", "/", NULL, MS_MOVE, NULL);
        ksys_chroot(".");
 }