On Tuesday 24 June 2008 17:11:01 Robert P. J. Day wrote: > i'm not sure if this is the proper forum for this, but while > perusing the early boot code, i noticed that selecting the config > variable BLK_DEV_INITRD gives you support for both initramfs, and an > initrd image. It gives you support for an _external_ initramfs. (I.E. the bootloader can load an external blob into memory and feed the physical address into the kernel via the ramdisk_start=12345 command line option. If this blob gunzips to a cpio image, it's extracted into rootfs. If it gunzips to a recognized filesystem type, it's used as an initrd.) The one built into the kernel is always used and can't be disabled, that I am aware of. If you have files in the static cpio archive and files in an internally supplied cpio archive, the file in the external one replaces the corresponding file in the internal one. > based on a quick inspection of the source under init/, it would seem > that you could whack out sizable chunks of code if you had no need for > initrd, but i could be wrong. If you disable BLK_DEV_INITRD you'll still have a cpio image built into your kernel: make allnoconfig make -j 3 It's possible that inclusion of the external image loading logic should be based on a symbol other than BLK_DEV_INITRD, since initramfs can use that logic when you never use a ram disk block device. It's a question of untangling stuff and figuring out how much config granularity you want... Rob -- "One of my most productive days was throwing away 1000 lines of code." - Ken Thompson. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
