Commit 16203a7a9422 ("initmpfs: make rootfs use tmpfs when CONFIG_TMPFS
enabled") introduced using tmpfs as the rootfs filesystem. The use of
tmpfs is limited to systems that do not specify "root=" on the boot
command line.
Without the check "!saved_root_name[0]", rootfs uses tmpfs. As there
must be a valid reason for this check, this patch introduces a new boot
command line option named "noramfs" to force rootfs to use tmpfs.
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 2 ++
init/do_mounts.c | 15 +++++++++++++--
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6571fbfdb2a1..fd82df2ff150 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2733,6 +2733,8 @@
nopcid [X86-64] Disable the PCID cpu feature.
+ noramfs Don't use ramfs for rootfs, use tmpfs.
+
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 7cf4f6dafd5f..74d8bfcd1294 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -315,6 +315,16 @@ static int __init root_data_setup(char *str)
return 1;
}
+static bool force_tmpfs;
+static int __init force_tmpfs_setup(char *str)
+{
+ if (*str)
+ return 0;
+ force_tmpfs = true;
+ return 1;
+
+}
+
static char * __initdata root_fs_names;
static int __init fs_names_setup(char *str)
{
@@ -332,6 +342,7 @@ static int __init root_delay_setup(char *str)
__setup("rootflags=", root_data_setup);
__setup("rootfstype=", fs_names_setup);
__setup("rootdelay=", root_delay_setup);
+__setup("noramfs", force_tmpfs_setup);
static void __init get_fs_names(char *page)
{
@@ -632,8 +643,8 @@ int __init init_rootfs(void)
if (err)
return err;
- if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
- (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
+ if (IS_ENABLED(CONFIG_TMPFS) && (force_tmpfs || (!saved_root_name[0] &&
+ (!root_fs_names || strstr(root_fs_names, "tmpfs"))))) {
err = shmem_init();
is_tmpfs = true;
} else {
--
2.7.5
--
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