diff options
authorDavid Howells <dhowells@redhat.com>2009-01-08 12:04:48 +0000
committerDavid Howells <dhowells@redhat.com>2009-01-08 12:04:48 +0000
commitcb6ff208076b5f434db1b8c983429269d719cef5 (patch)
parentab2e83ead4eca9e045daac4cbf66eb1e7a244bb2 (diff)
NOMMU: Support XIP on initramfs
Support XIP on files unpacked from the initramfs image on NOMMU systems. This simply requires the length of the file to be preset so that the ramfs fs can attempt to garner sufficient contiguous storage to store the file (NOMMU mmap can only map contiguous RAM). All the other bits to do XIP on initramfs files are present: (1) ramfs's truncate attempts to allocate a contiguous run of pages when a file is truncated upwards from nothing. (2) ramfs sets BDI on its files to indicate direct mapping is possible, and that its files can be mapped for read, write and exec. (3) NOMMU mmap() will use the above bits to determine that it can do XIP. Possibly this needs better controls, because it will _always_ try and do XIP. One disadvantage of this very simplistic approach is that sufficient space will be allocated to store the whole file, and not just the bit that would be XIP'd. To deal with this, though, the initramfs unpacker would have to be able to parse the file contents. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
1 files changed, 1 insertions, 0 deletions
diff --git a/init/initramfs.c b/init/initramfs.c
index 4f5ba75aaa7..d9c941c0c3c 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -317,6 +317,7 @@ static int __init do_name(void)
if (wfd >= 0) {
sys_fchown(wfd, uid, gid);
sys_fchmod(wfd, mode);
+ sys_ftruncate(wfd, body_len);
vcollected = kstrdup(collected, GFP_KERNEL);
state = CopyFile;