Arch Linux

Marcos FRM

Member

Registered: 2013-02-10

Posts: 14

About changing kernel config for an initramfs-less boot

As a former Fedora user, I miss in Arch the ability to boot without an initramfs.

Diff to Fedora's kernel config (relevant bits only):

-CONFIG_SCSI_MOD=m
+CONFIG_SCSI_MOD=y

-CONFIG_SCSI=m
+CONFIG_SCSI=y

-CONFIG_BLK_DEV_SD=m
+CONFIG_BLK_DEV_SD=y

-CONFIG_BLK_DEV_SR=m
+CONFIG_BLK_DEV_SR=y

-CONFIG_CHR_DEV_SG=m
+CONFIG_CHR_DEV_SG=y

-CONFIG_ATA=m
+CONFIG_ATA=y

-CONFIG_SATA_AHCI=m
+CONFIG_SATA_AHCI=y

-CONFIG_ATA_PIIX=m
+CONFIG_ATA_PIIX=y

-CONFIG_EXT4_FS=m
+CONFIG_EXT4_FS=y

Fedora devs choose a small set of settings to be bult-in (SCSI disk/cdrom, AHCI, PIIX, EXT4). It covers a large number of machines (and VMs), as today the majority of chipsets support AHCI and EXT4 is the de-facto standard filesystem (EXT2/3 can also be mounted with CONFIG_EXT4_USE_FOR_EXT23).

I recompiled Arch's default kernel with these modifications and it worked just fine without initramfs.

Would it be feasible to Arch adopt this?

Linux 3.8 will support PARTUUID for MBR partitioned disks:
http://git.kernel.org/?p=linux/kernel/g … ed7323f9d2

We that still use MBR will have a reliable way to specify the root device, especially for people who have multiple disks.

The Solutor

Member

From: Italy

Registered: 2013-02-10

Posts: 10

Re: About changing kernel config for an initramfs-less boot

I did almost the same thing yesterday, following a slightly different path: configured the kernel (vanilla3.8-rc7 ) with make localyesconfig, then i reverted back to modules the parts that made more sense if modularized (like the usb stuff).

It worked w/o major problems, the UUID thing is already present on the 3.8-rc7 kernel, and i even enabled it, but I haven't experimented if it works for now I'm booting via the classical device names (/dev/sdX)

Last edited by The Solutor (2013-02-12 17:16:46)