USB Flash rootfs prep!

USB Flash rootfs prep!

[Cristian Axenie]

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Hello all !
I'm porting a former Control application from x86 (Linux+RTAI+Comedi) to
PowerPC (Xenomai+Comedi for RTDM). I've choosed for my development the ELDK
tool and a MPC8315ERDB platform. So I 've properly patched and build my
kernel with the Xenomai support and I get some errors when running a latency
test app. I've managed to spot the problem , that consists in an
incompatibility between the shared libraries used on the target (ver 2.5)
and the standard libraries used (and with which were compiled the kernel and
the Xenomai addon) version 2.6, and so ld screams and a SegFault appears.
Now I,ve creted an ext2.img rootfs with the rootfs.tar.gz from
/eldk/ppc_6xx/images and I've added in the rootfs some libs and other useful
stuff for Xenomai for elliminating the need for an NFS mount.
My primary concern is now to write the new FS to a USB Flash Stick so that I
can test if the latency tests works now when the libs are compatible (ver
2.6).
So resuming I want to now what are the corect steps to do this, because I've
tried to write the generated ext2.img to my USB flash stick (formated as
ext2) and added to the uBoot bootargs to the following :

setenv usbstick_args setenv bootargs root=/dev/sdb1 ro rootdelay=10
rootfstype=ext2 console=$consoledev,$baudrate;
setenv usbstick 'run usbstick_args;bootm fe500000 - fe700000'
setenv bootcmd run usbstick

As a result I get the following output :

Waiting 10sec before mounting root device...
scsi 2:0:0:0: Direct-Access     SanDisk  Cruzer Micro     0.1  PQ: 0 ANSI: 2
sd 2:0:0:0: [sdb] 2001888 512-byte hardware sectors (1025 MB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Assuming drive cache: write through
sd 2:0:0:0: [sdb] 2001888 512-byte hardware sectors (1025 MB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Assuming drive cache: write through
 sdb: sdb1
sd 2:0:0:0: [sdb] Attached SCSI removable disk
sd 2:0:0:0: Attached scsi generic sg1 type 0
VFS: Mounted root (ext2 filesystem) readonly.
Freeing unused kernel memory: 156k init
Warning: unable to open an initial console.
Failed to execute /bin/busybox.  Attempting defaults...
Kernel panic - not syncing: No init found.  Try passing init= option to
kernel.
Rebooting in 180 seconds..

Shall I explicitly give the init ? What should be ... init=/sbin/init,
init=/bin/busybox ????

Thanks in advance !!!

Best regards ,
Cristian

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Re: USB Flash rootfs prep!

[Joachim Foerster]

Hi Cristian,

On Sat, 2008-11-15 at 03:05 +0200, Cristian Axenie wrote:
> VFS: Mounted root (ext2 filesystem) readonly.
> Freeing unused kernel memory: 156k init
> Warning: unable to open an initial console.

Device file /dev/console doesn't seem to exist in your rootfs. 

> Failed to execute /bin/busybox.  Attempting defaults...
> Kernel panic - not syncing: No init found.  Try passing init= option
> to kernel.

It seems that you don't have an executable called /bin/busybox in your
rootfs. Your kernel command line seems to have "init=/bin/busybox"
included?

But, hmmm, it is very strange, at least in your uboot bootargs there is
no such string. Is it because of some default kernel command line (set
before compiling the kernel)?

> Rebooting in 180 seconds..
> 
> Shall I explicitly give the init ? What should be ... init=/sbin/init,
> init=/bin/busybox ????

The rootfs which comes with ELDK "starts" with /sbin/init - it does not
use busybox, right (as far as I can remember)? So you need to specify
"init=/sbin/init" on your kernel command line.

 Joachim

Re: USB Flash rootfs prep!

[Cristian Axenie]

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On Sat, Nov 15, 2008 at 11:12 AM, Cristian Axenie <cristian.axenie@gmail.com
> wrote:

>
>
> On Sat, Nov 15, 2008 at 10:18 AM, Joachim Foerster <mls.JOFT@gmx.de>wrote:
>
>> Hi Cristian,
>>
>> On Sat, 2008-11-15 at 03:05 +0200, Cristian Axenie wrote:
>> > VFS: Mounted root (ext2 filesystem) readonly.
>> > Freeing unused kernel memory: 156k init
>> > Warning: unable to open an initial console.
>>
>> Device file /dev/console doesn't seem to exist in your rootfs.
>
> Strange because /dev/console exists in my ext2.img.
>
>>
>>
>> > Failed to execute /bin/busybox.  Attempting defaults...
>> > Kernel panic - not syncing: No init found.  Try passing init= option
>> > to kernel.
>>
>> It seems that you don't have an executable called /bin/busybox in your
>> rootfs. Your kernel command line seems to have "init=/bin/busybox"
>> included?
>>
>> But, hmmm, it is very strange, at least in your uboot bootargs there is
>> no such string. Is it because of some default kernel command line (set
>> before compiling the kernel)?
>
>
> I simply forgot to write them here (because I didn't knew if they were
> valid) but I 've tried with init=/sbin/init and get the same result !
>
>>
>>
>> > Rebooting in 180 seconds..
>> >
>> > Shall I explicitly give the init ? What should be ... init=/sbin/init,
>> > init=/bin/busybox ????
>>
>> The rootfs which comes with ELDK "starts" with /sbin/init - it does not
>> use busybox, right (as far as I can remember)? So you need to specify
>> "init=/sbin/init" on your kernel command line.
>
>
> I've tried with /sbin/init and the same !!
>
>>
>>
>>  Joachim
>>
>>
>>
> Cristian
>

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Re: USB Flash rootfs prep!

[Nicholas Mc Guire]

>
> >
> >
> > On Sat, Nov 15, 2008 at 10:18 AM, Joachim Foerster <mls.JOFT@gmx.de>wrote:
> >
> >> Hi Cristian,
> >>
> >> On Sat, 2008-11-15 at 03:05 +0200, Cristian Axenie wrote:
> >> > VFS: Mounted root (ext2 filesystem) readonly.
> >> > Freeing unused kernel memory: 156k init
> >> > Warning: unable to open an initial console.
> >>
> >> Device file /dev/console doesn't seem to exist in your rootfs.
> >
> > Strange because /dev/console exists in my ext2.img.

did you check that it is actually a valid character device (c 5 1) ?
it can easaly happend during copying of a tree into your image that
they become regular files.

hofrat

Re: USB Flash rootfs prep!

[Cristian Axenie]

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On Sat, Nov 15, 2008 at 12:01 PM, Nicholas Mc Guire <hofrat@hofr.at> wrote:

> >
> > >
> > >
> > > On Sat, Nov 15, 2008 at 10:18 AM, Joachim Foerster <mls.JOFT@gmx.de
> >wrote:
> > >
> > >> Hi Cristian,
> > >>
> > >> On Sat, 2008-11-15 at 03:05 +0200, Cristian Axenie wrote:
> > >> > VFS: Mounted root (ext2 filesystem) readonly.
> > >> > Freeing unused kernel memory: 156k init
> > >> > Warning: unable to open an initial console.
> > >>
> > >> Device file /dev/console doesn't seem to exist in your rootfs.
> > >
> > > Strange because /dev/console exists in my ext2.img.
>
> did you check that it is actually a valid character device (c 5 1) ?
> it can easaly happend during copying of a tree into your image that
> they become regular files.
>
> hofrat
>
I think that you are right, butr how can I test this validity??

Cristian

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Re: USB Flash rootfs prep!

[Nicholas Mc Guire]

> >
> > did you check that it is actually a valid character device (c 5 1) ?
> > it can easaly happend during copying of a tree into your image that
> > they become regular files.
> >
> > hofrat
> >
> I think that you are right, butr how can I test this validity??
>
just check with ls -l that the device file is actually still a character
device with the right major/minor number.

crw--w--w-    1 root     tty        5,   1 Nov 13 22:18 /mnt/dev/console

modes and date of course may be diferent.

hofrat

Re: USB Flash rootfs prep!

[Cristian Axenie]

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On Sat, Nov 15, 2008 at 12:40 PM, Nicholas Mc Guire <hofrat@hofr.at> wrote:

> > >
> > > did you check that it is actually a valid character device (c 5 1) ?
> > > it can easaly happend during copying of a tree into your image that
> > > they become regular files.
> > >
> > > hofrat
> > >
> > I think that you are right, butr how can I test this validity??
> >
> just check with ls -l that the device file is actually still a character
> device with the right major/minor number.
>
> crw--w--w-    1 root     tty        5,   1 Nov 13 22:18 /mnt/dev/console
>
> modes and date of course may be diferent.
>
> hofrat
>

I mount my ext2.img and run ls -l and I get

crw-r----- 1 root root   5,   1 2008-11-15 02:24 console

I think is not ok ?!


Now regarding some steps in the creation of the rootfs:

use "tmpfs" for cases where a writable file system is needed and add the
following lines to the /etc/rc.sh script:

# mount TMPFS because root-fs is readonly
/bin/mount -t tmpfs -o size=2M tmpfs /tmpfs

create the same symbolic links for device files that must be placed in a
writable filesystem:  dev/ptyp0 → /tmpfs/dev/ptyp0     dev/ttyp0 →
/tmpfs/dev/ttyp0
 dev/ptyp1 → /tmpfs/dev/ptyp1     dev/ttyp1 → /tmpfs/dev/ttyp1
dev/ptyp2 → /tmpfs/dev/ptyp2
    dev/ttyp2 → /tmpfs/dev/ttyp2  dev/ptyp3 → /tmpfs/dev/ptyp3     dev/ttyp3
→ /tmpfs/dev/ttyp3  dev/ptyp4 → /tmpfs/dev/ptyp4     dev/ttyp4 →
/tmpfs/dev/ttyp4
 dev/ptyp5 → /tmpfs/dev/ptyp5     dev/ttyp5 → /tmpfs/dev/ttyp5
dev/ptyp6 → /tmpfs/dev/ptyp6
    dev/ttyp6 → /tmpfs/dev/ttyp6  dev/ptyp7 → /tmpfs/dev/ptyp7     dev/ttyp7
→ /tmpfs/dev/ttyp7  dev/ptyp8 → /tmpfs/dev/ptyp8     dev/ttyp8 →
/tmpfs/dev/ttyp8
 dev/ptyp9 → /tmpfs/dev/ptyp9     dev/ttyp9 → /tmpfs/dev/ttyp9
dev/ptypa → /tmpfs/dev/ptypa
    dev/ttypa → /tmpfs/dev/ttypa  dev/ptypb → /tmpfs/dev/ptypb     dev/ttypb
→ /tmpfs/dev/ttypb  dev/ptypc → /tmpfs/dev/ptypc     dev/ttypc →
/tmpfs/dev/ttypc
 dev/ptypd → /tmpfs/dev/ptypd     dev/ttypd → /tmpfs/dev/ttypd
dev/ptype → /tmpfs/dev/ptype
    dev/ttype → /tmpfs/dev/ttype  dev/ptypf → /tmpfs/dev/ptypf     dev/ttypf
→ /tmpfs/dev/ttypf  tmp → /tmpfs/tmp     var → /tmpfs/var  dev/log →
/var/log/log
         In case you use dhclient also:  etc/dhclient.conf →
/tmpfs/var/lib/dhclient.conf
    etc/resolv.conf → /tmpfs/var/lib/resolv.conf
Shall I create the symlinks manually?
Is rc.sh executed ??

I,ve created a tmpfs directory in my rootfs directory and even if I mount it
on my host it's not populateed.
  place the corresponding directories and device files in the tmpfs file
system, the following code is added to the /etc/rc.sh script:

mkdir -p /tmpfs/tmp /tmpfs/dev \
         /tmpfs/var/lib/dhcp /tmpfs/var/lock /tmpfs/var/run

while read name minor
do
        mknod /tmpfs/dev/ptyp$name c 2 $minor
        mknod /tmpfs/dev/ttyp$name c 3 $minor
done <<__EOD__
0  0
1  1
2  2
3  3
4  4
5  5
6  6
7  7
8  8
9  9
a 10
b 11
c 12
d 13
e 14
f 15
__EOD__
chmod 0666 /tmpfs/dev/*



Cristian

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Re: USB Flash rootfs prep!

[Cristian Axenie]

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So I mounted the ext2.img on my host and the /dev/console is not a regular
file. If it helps or clears some aspects this is the contetnt of
rootfs_devices.tab used at the ext2.img generation :

#<name>    <type> <mode> <uid> <gid> <major> <minor> <start>  <inc>  <count>
/dev            d  755  0       0        -      -       -       -       -
/dev/console    c  640  0       0        5      1       -       -       -
/dev/fb0        c  640  0       0       29      0       -       -       -
/dev/full       c  640  0       0        1      7       -       -       -
/dev/hda        b  640  0       0        3      0       -       -       -
/dev/hda        b  640  0       0        3      1       1       1       16
/dev/kmem       c  640  0       0        1      2       -       -       -
/dev/mem        c  640  0       0        1      1       -       -       -
/dev/mtd        c  640  0       0       90      0       0       2       16
/dev/mtdblock   b  640  0       0       31      0       0       1       16
/dev/mtdr       c  640  0       0       90      1       0       2       16
/dev/nftla      b  640  0       0       93      0       -       -       -
/dev/nftla      b  640  0       0       93      1       1       1       8
/dev/nftlb      b  640  0       0       93      16      -       -       -
/dev/nftlb      b  640  0       0       93      17      1       1       8
/dev/null       c  640  0       0        1      3       -       -       -
/dev/ptyp       c  640  0       0        2      0       0       1       10
/dev/ptypa      c  640  0       0        2      10      -       -       -
/dev/ptypb      c  640  0       0        2      11      -       -       -
/dev/ptypc      c  640  0       0        2      12      -       -       -
/dev/ptypd      c  640  0       0        2      13      -       -       -
/dev/ptype      c  640  0       0        2      14      -       -       -
/dev/ptypf      c  640  0       0        2      15      -       -       -
/dev/ram        b  640  0       0        1      0       0       1       2
/dev/ram        b  640  0       0        1      1       -       -       -
/dev/rtc        c  640  0       0       10      135     -       -       -
/dev/tty        c  640  0       0        4      0       0       1       4
/dev/tty        c  640  0       0        5      0       -       -       -
/dev/ttyS       c  640  0       0        4      64      0       1       8
/dev/ttyp       c  640  0       0        3      0       0       1       10
/dev/ttypa      c  640  0       0        3      10      -       -       -
/dev/ttypb      c  640  0       0        3      11      -       -       -
/dev/ttypc      c  640  0       0        3      12      -       -       -
/dev/ttypd      c  640  0       0        3      13      -       -       -
/dev/ttype      c  640  0       0        3      14      -       -       -
/dev/ttypf      c  640  0       0        3      15      -       -       -
/dev/zero       c  640  0       0        1      5       -       -       -

Am I missing something ??? The ext2 formatting of the USB Flash Stick is
influencing this ?
 Can you spot a probable cause ?
Thank you !
Cristian

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Re: USB Flash rootfs prep!

[Cristian Axenie]

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On Sat, Nov 15, 2008 at 6:02 PM, Nicholas Mc Guire <hofrat@hofr.at> wrote:

> > >
> >
> > I mount my ext2.img and run ls -l and I get
> >
> > crw-r----- 1 root root   5,   1 2008-11-15 02:24 console
> >
> > I think is not ok ?!
> >
> >
>
> thats fine - so that should not be your problem.
>
> what is the console device set to ? can you pass it an explicid
>
> console=/dev/ttyS0 or the like to map it to a device that exists for sure
> and is in /dev/ ? off course you also have to check that the driver
> support is in the kernel.
>
> hofrat


I've managed to solve my problem. I took a clean ramdisk (that came with the
ELDK) mount it , added my needed libs, devs and test apps , then generated
an ramdisk.img (using genext2fs) , compressed it and then created an uBoot
image file. The modified rootfs is now on my USB Flash stick and it works.
My USB Flash rootfs is loaded properly by the kernel and related to my
initial problem, to be more specific,  I've created a root filesystem on my
USB Flash stick where I added the xenomai dir (including /bin /lib
/include...) generated during the Xenomai (from the trunk) install and also
the devices rtheap rtp0... in the /dev directory of my FS. I also used the
proper libc-2.6 standard shared libraries so the dynamic linker does't send
a SIGSEGV anymore and  I am able now to run ./latency or ./cyclictest). I
don't receive SegFault anymore.

Thanks to all,
Cristian

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