What device for ROMFS ?

What device for ROMFS ?

[Marc-F. LUCCA-DANIAU]

Hello,

In a few words: what is the device to be used for a ROMFS root ?

More: I configured ELKS as a ROM image for an embedded system, and I run 
it under EMU86, but I cannot figure out:

1- how to tell ELKS to read the ROMFS superblock from ROM address space?
2- how to build a ROMFS image to put in the ROM address space?

All my tries end up with the well known:

$ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i

$ ./pcat `cat emu86.pts`
Loading kernel image...
Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
ELKS kernel (39008 text + 4168 data + 48648 bss)
Kernel text at e062:0000, data at 90:0000 62 K of memory for user processes.
ELKS network sockets
TCP/IP stack by Harry Kalogirou
ELKS version 0.2.0
panic: VFS: Unable to mount root fs on 206D
apparent call stack:
Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
    0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
    1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
    2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
    3: 1048 => 0000 0000 0000 0000 0000 0000 0000
    4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
    5: 1048 => 0000 0000 0000 0000 0000 0000 0000
    6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
    7: 1048 => 0000 0000 0000 0000 0000 0000 0000
    8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:

Any suggestion ?

Thanks,

MFLD

Re: What device for ROMFS ?

[Juan Perez-Sanchez]

Hello:

For the standard case, the root device is defined by the
arch/i86/tools/build program (see Documentation/text/boot.txt). The
device number is saved in bytes 508,509 of boot sector.

After booting, the root device number is read from that location into
the ROOT_DEV variable by the function setup_arch() in
arch/i86/kernel/system.c.

Maybe the mkbootloader does not define the root device as expected by
the kernel.

In addition, you will have to write a ROM block device driver. Also, I
think romfs for ELKS never reached a working status.

Juan


On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
<mfld.fr@gmail.com> wrote:
> Hello,
>
> In a few words: what is the device to be used for a ROMFS root ?
>
> More: I configured ELKS as a ROM image for an embedded system, and I run it
> under EMU86, but I cannot figure out:
>
> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
> 2- how to build a ROMFS image to put in the ROM address space?
>
> All my tries end up with the well known:
>
> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>
> $ ./pcat `cat emu86.pts`
> Loading kernel image...
> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
> ELKS kernel (39008 text + 4168 data + 48648 bss)
> Kernel text at e062:0000, data at 90:0000 62 K of memory for user processes.
> ELKS network sockets
> TCP/IP stack by Harry Kalogirou
> ELKS version 0.2.0
> panic: VFS: Unable to mount root fs on 206D
> apparent call stack:
> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>    0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>    1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>    2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>
> Any suggestion ?
>
> Thanks,
>
> MFLD
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: What device for ROMFS ?

[Marc-François LUCCA-DANIAU]

Thanks Juan for that info.

It helped me to find some missing #define in the setup configuration
reading.
I will commit the related fixes later (because not so many people using ROM
boot for ELKS :-)).

Coding a fresh new block device is one solution, but the ROM is by nature a
flat and linear device (except when erasing / writting).

So I would rather refactor the existing ROMFS to directly pick data from a
given area in the ROM, and that area to be described in the ELKS config,
like the other ROM options.

Does it make sense ?

MFLD


> Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>
> Hello:
>
> For the standard case, the root device is defined by the
> arch/i86/tools/build program (see Documentation/text/boot.txt). The
> device number is saved in bytes 508,509 of boot sector.
>
> After booting, the root device number is read from that location into
> the ROOT_DEV variable by the function setup_arch() in
> arch/i86/kernel/system.c.
>
> Maybe the mkbootloader does not define the root device as expected by
> the kernel.
>
> In addition, you will have to write a ROM block device driver. Also, I
> think romfs for ELKS never reached a working status.
>
> Juan
>
>
> On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
> <mfld.fr@gmail.com> wrote:
>
> Hello,
>
> In a few words: what is the device to be used for a ROMFS root ?
>
> More: I configured ELKS as a ROM image for an embedded system, and I run it
> under EMU86, but I cannot figure out:
>
> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
> 2- how to build a ROMFS image to put in the ROM address space?
>
> All my tries end up with the well known:
>
> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>
> $ ./pcat `cat emu86.pts`
> Loading kernel image...
> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
> ELKS kernel (39008 text + 4168 data + 48648 bss)
> Kernel text at e062:0000, data at 90:0000 62 K of memory for user processes.
> ELKS network sockets
> TCP/IP stack by Harry Kalogirou
> ELKS version 0.2.0
> panic: VFS: Unable to mount root fs on 206D
> apparent call stack:
> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>    0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>    1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>    2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>
> Any suggestion ?
>
> Thanks,
>
> MFLD
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
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Re: What device for ROMFS ?

[Marc-François LUCCA-DANIAU]

I do not intend to implement banked memory support, neither on my real
SBC that has not such, nor in the EMU86 emulator where I test my SW
before burning it to that SBC Flash. Just because I don't need it.
512K RAM and 512K ROM are enough for running ELKS with a confortable
margin, especially when the code segment of the kernel is in ROM and
let 40 K of additionnal RAM space.

The only constrained area is the root image to be stored in ROM : a
full3 image for 1.44 MB floppy cannot fit in 512 K of ROM, so I have
to think a bit about it. First of all, all the ELKS cmdlets are not
needed for that target. And second, floppy is a block device, and so
wastes lot a space because of block aligment. ROM has no alignement
concern. Plus removing the bootloader & the kernel (already in ROM as
raw blocks). Etc...

This would not be the same story on a 8-bits system. You can have a
look to Alan's FUZZIX project presentation, where the banked memory is
a must-have : https://github.com/EtchedPixels/FUZIX

MFLD


2016-05-26 11:41 GMT+02:00 Kirn Gill <segin2005@gmail.com>:
> Does this work for banked ROM? Or are ROMFS builds expected to fit within
> the 8086 memory space?
>
> On May 26, 2016 02:24, "Marc-François LUCCA-DANIAU" <mfld.fr@gmail.com>
> wrote:
>>
>> Thanks Juan for that info.
>>
>> It helped me to find some missing #define in the setup configuration
>> reading.
>> I will commit the related fixes later (because not so many people using
>> ROM
>> boot for ELKS :-)).
>>
>> Coding a fresh new block device is one solution, but the ROM is by nature
>> a
>> flat and linear device (except when erasing / writting).
>>
>> So I would rather refactor the existing ROMFS to directly pick data from a
>> given area in the ROM, and that area to be described in the ELKS config,
>> like the other ROM options.
>>
>> Does it make sense ?
>>
>> MFLD
>>
>>
>> > Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>> >
>> > Hello:
>> >
>> > For the standard case, the root device is defined by the
>> > arch/i86/tools/build program (see Documentation/text/boot.txt). The
>> > device number is saved in bytes 508,509 of boot sector.
>> >
>> > After booting, the root device number is read from that location into
>> > the ROOT_DEV variable by the function setup_arch() in
>> > arch/i86/kernel/system.c.
>> >
>> > Maybe the mkbootloader does not define the root device as expected by
>> > the kernel.
>> >
>> > In addition, you will have to write a ROM block device driver. Also, I
>> > think romfs for ELKS never reached a working status.
>> >
>> > Juan
>> >
>> >
>> > On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
>> > <mfld.fr@gmail.com> wrote:
>> >
>> > Hello,
>> >
>> > In a few words: what is the device to be used for a ROMFS root ?
>> >
>> > More: I configured ELKS as a ROM image for an embedded system, and I run
>> > it
>> > under EMU86, but I cannot figure out:
>> >
>> > 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
>> > 2- how to build a ROMFS image to put in the ROM address space?
>> >
>> > All my tries end up with the well known:
>> >
>> > $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>> >
>> > $ ./pcat `cat emu86.pts`
>> > Loading kernel image...
>> > Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
>> > PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
>> > ELKS kernel (39008 text + 4168 data + 48648 bss)
>> > Kernel text at e062:0000, data at 90:0000 62 K of memory for user
>> > processes.
>> > ELKS network sockets
>> > TCP/IP stack by Harry Kalogirou
>> > ELKS version 0.2.0
>> > panic: VFS: Unable to mount root fs on 206D
>> > apparent call stack:
>> > Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>> >    0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>> >    1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>> >    2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>> >    3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>> >    4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>> >    5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>> >    6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>> >    7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>> >    8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>> > SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>> >
>> > Any suggestion ?
>> >
>> > Thanks,
>> >
>> > MFLD
>> >
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-8086" in
>> > the body of a message to majordomo@vger.kernel.org
>> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> >
>> >
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
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Re: What device for ROMFS ?

[One Thousand Gnomes]

> This would not be the same story on a 8-bits system. You can have a
> look to Alan's FUZZIX project presentation, where the banked memory is
> a must-have : https://github.com/EtchedPixels/FUZIX

The Z180 based FUZIX systems effectively have some minimal segmentation
rather than simple banking. You just need enough address space, and I
agree 512K of memory is tons for a well written OS. I don't think I've
ever managed to find a reason to use all the 512K of RAM on a Z180 based
FUZIX box !

The other advantage of ROM if all mapped is that with a bit of tweaking
you should be able to just insert the ROM banks into the segment map when
you do an execve so that split I/D ('small rather than tiny in DOS
speak') binaries can run with the code running directly from the ROM and
taking no RAM space at all.

Alan

Re: What device for ROMFS ?

[Juan Perez-Sanchez]

Looks good. That would be an interesting contribution to this project.
Later, you could add Execute In Place (XIP) to this modified ROMFS.

Juan


On Thu, May 26, 2016 at 2:20 AM, Marc-F. LUCCA-DANIAU <mfld.fr@gmail.com> wrote:
> Thanks Juan for that info.
>
> It helped me to find some missing #define in the setup configuration
> reading.
> I will commit the related fixes later (because not so many people using ROM
> boot for ELKS :-)).
>
> Coding a fresh new block device is one solution, but the ROM is by nature a
> flat and linear device (except when erasing / writting).
>
> So I would rather refactor the existing ROMFS to directly pick data from a
> given area in the ROM, and that area to be described in the ELKS config,
> like the other ROM options.
>
> Does it make sense ?
>
> MFLD
>
>
> Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>
> Hello:
>
> For the standard case, the root device is defined by the
> arch/i86/tools/build program (see Documentation/text/boot.txt). The
> device number is saved in bytes 508,509 of boot sector.
>
> After booting, the root device number is read from that location into
> the ROOT_DEV variable by the function setup_arch() in
> arch/i86/kernel/system.c.
>
> Maybe the mkbootloader does not define the root device as expected by
> the kernel.
>
> In addition, you will have to write a ROM block device driver. Also, I
> think romfs for ELKS never reached a working status.
>
> Juan
>
>
> On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
> <mfld.fr@gmail.com> wrote:
>
> Hello,
>
> In a few words: what is the device to be used for a ROMFS root ?
>
> More: I configured ELKS as a ROM image for an embedded system, and I run it
> under EMU86, but I cannot figure out:
>
> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
> 2- how to build a ROMFS image to put in the ROM address space?
>
> All my tries end up with the well known:
>
> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>
> $ ./pcat `cat emu86.pts`
> Loading kernel image...
> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
> ELKS kernel (39008 text + 4168 data + 48648 bss)
> Kernel text at e062:0000, data at 90:0000 62 K of memory for user processes.
> ELKS network sockets
> TCP/IP stack by Harry Kalogirou
> ELKS version 0.2.0
> panic: VFS: Unable to mount root fs on 206D
> apparent call stack:
> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>    0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>    1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>    2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>    7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>    8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>
> Any suggestion ?
>
> Thanks,
>
> MFLD
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
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Re: What device for ROMFS ?

[Marc-F. LUCCA-DANIAU]

Tracked by :

https://github.com/mfld-fr/elks/issues/2

MFLD



Le 27/05/2016 à 00:36, Juan Perez-Sanchez a écrit :
> Looks good. That would be an interesting contribution to this project.
> Later, you could add Execute In Place (XIP) to this modified ROMFS.
>
> Juan
>
>
> On Thu, May 26, 2016 at 2:20 AM, Marc-F. LUCCA-DANIAU <mfld.fr@gmail.com> wrote:
>> Thanks Juan for that info.
>>
>> It helped me to find some missing #define in the setup configuration
>> reading.
>> I will commit the related fixes later (because not so many people using ROM
>> boot for ELKS :-)).
>>
>> Coding a fresh new block device is one solution, but the ROM is by nature a
>> flat and linear device (except when erasing / writting).
>>
>> So I would rather refactor the existing ROMFS to directly pick data from a
>> given area in the ROM, and that area to be described in the ELKS config,
>> like the other ROM options.
>>
>> Does it make sense ?
>>
>> MFLD
>>
>>
>> Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>>
>> Hello:
>>
>> For the standard case, the root device is defined by the
>> arch/i86/tools/build program (see Documentation/text/boot.txt). The
>> device number is saved in bytes 508,509 of boot sector.
>>
>> After booting, the root device number is read from that location into
>> the ROOT_DEV variable by the function setup_arch() in
>> arch/i86/kernel/system.c.
>>
>> Maybe the mkbootloader does not define the root device as expected by
>> the kernel.
>>
>> In addition, you will have to write a ROM block device driver. Also, I
>> think romfs for ELKS never reached a working status.
>>
>> Juan
>>
>>
>> On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
>> <mfld.fr@gmail.com> wrote:
>>
>> Hello,
>>
>> In a few words: what is the device to be used for a ROMFS root ?
>>
>> More: I configured ELKS as a ROM image for an embedded system, and I run it
>> under EMU86, but I cannot figure out:
>>
>> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
>> 2- how to build a ROMFS image to put in the ROM address space?
>>
>> All my tries end up with the well known:
>>
>> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>>
>> $ ./pcat `cat emu86.pts`
>> Loading kernel image...
>> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
>> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
>> ELKS kernel (39008 text + 4168 data + 48648 bss)
>> Kernel text at e062:0000, data at 90:0000 62 K of memory for user processes.
>> ELKS network sockets
>> TCP/IP stack by Harry Kalogirou
>> ELKS version 0.2.0
>> panic: VFS: Unable to mount root fs on 206D
>> apparent call stack:
>> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>>     0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>>     1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>>     2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>     3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>     4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>     5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>     6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>     7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>     8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>>
>> Any suggestion ?
>>
>> Thanks,
>>
>> MFLD
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>

Re: What device for ROMFS ?

[Marc-François LUCCA-DANIAU]

Tracked by :

https://github.com/mfld-fr/elks/issues/2

MFLD
>
> Le 27/05/2016 à 00:36, Juan Perez-Sanchez a écrit :
>>
>> Looks good. That would be an interesting contribution to this project.
>> Later, you could add Execute In Place (XIP) to this modified ROMFS.
>>
>> Juan
>>
>>
>> On Thu, May 26, 2016 at 2:20 AM, Marc-F. LUCCA-DANIAU <mfld.fr@gmail.com>
>> wrote:
>>>
>>> Thanks Juan for that info.
>>>
>>> It helped me to find some missing #define in the setup configuration
>>> reading.
>>> I will commit the related fixes later (because not so many people using
>>> ROM
>>> boot for ELKS :-)).
>>>
>>> Coding a fresh new block device is one solution, but the ROM is by nature
>>> a
>>> flat and linear device (except when erasing / writting).
>>>
>>> So I would rather refactor the existing ROMFS to directly pick data from
>>> a
>>> given area in the ROM, and that area to be described in the ELKS config,
>>> like the other ROM options.
>>>
>>> Does it make sense ?
>>>
>>> MFLD
>>>
>>>
>>> Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>>>
>>> Hello:
>>>
>>> For the standard case, the root device is defined by the
>>> arch/i86/tools/build program (see Documentation/text/boot.txt). The
>>> device number is saved in bytes 508,509 of boot sector.
>>>
>>> After booting, the root device number is read from that location into
>>> the ROOT_DEV variable by the function setup_arch() in
>>> arch/i86/kernel/system.c.
>>>
>>> Maybe the mkbootloader does not define the root device as expected by
>>> the kernel.
>>>
>>> In addition, you will have to write a ROM block device driver. Also, I
>>> think romfs for ELKS never reached a working status.
>>>
>>> Juan
>>>
>>>
>>> On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
>>> <mfld.fr@gmail.com> wrote:
>>>
>>> Hello,
>>>
>>> In a few words: what is the device to be used for a ROMFS root ?
>>>
>>> More: I configured ELKS as a ROM image for an embedded system, and I run
>>> it
>>> under EMU86, but I cannot figure out:
>>>
>>> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
>>> 2- how to build a ROMFS image to put in the ROM address space?
>>>
>>> All my tries end up with the well known:
>>>
>>> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>>>
>>> $ ./pcat `cat emu86.pts`
>>> Loading kernel image...
>>> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
>>> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
>>> ELKS kernel (39008 text + 4168 data + 48648 bss)
>>> Kernel text at e062:0000, data at 90:0000 62 K of memory for user
>>> processes.
>>> ELKS network sockets
>>> TCP/IP stack by Harry Kalogirou
>>> ELKS version 0.2.0
>>> panic: VFS: Unable to mount root fs on 206D
>>> apparent call stack:
>>> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>>>     0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>>>     1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>>>     2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>>>
>>> Any suggestion ?
>>>
>>> Thanks,
>>>
>>> MFLD
>>>
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>

Re: What device for ROMFS ?

[Marc-F. LUCCA-DANIAU]

Not forgotten and tracked by :

https://github.com/mfld-fr/elks/issues/2

MFLD

>
> Le 27/05/2016 à 00:36, Juan Perez-Sanchez a écrit :
>>
>> Looks good. That would be an interesting contribution to this project.
>> Later, you could add Execute In Place (XIP) to this modified ROMFS.
>>
>> Juan
>>
>>
>> On Thu, May 26, 2016 at 2:20 AM, Marc-F. LUCCA-DANIAU <mfld.fr@gmail.com>
>> wrote:
>>>
>>> Thanks Juan for that info.
>>>
>>> It helped me to find some missing #define in the setup configuration
>>> reading.
>>> I will commit the related fixes later (because not so many people using
>>> ROM
>>> boot for ELKS :-)).
>>>
>>> Coding a fresh new block device is one solution, but the ROM is by nature
>>> a
>>> flat and linear device (except when erasing / writting).
>>>
>>> So I would rather refactor the existing ROMFS to directly pick data from
>>> a
>>> given area in the ROM, and that area to be described in the ELKS config,
>>> like the other ROM options.
>>>
>>> Does it make sense ?
>>>
>>> MFLD
>>>
>>>
>>> Le 24/05/2016 01:07, Juan Perez-Sanchez a écrit :
>>>
>>> Hello:
>>>
>>> For the standard case, the root device is defined by the
>>> arch/i86/tools/build program (see Documentation/text/boot.txt). The
>>> device number is saved in bytes 508,509 of boot sector.
>>>
>>> After booting, the root device number is read from that location into
>>> the ROOT_DEV variable by the function setup_arch() in
>>> arch/i86/kernel/system.c.
>>>
>>> Maybe the mkbootloader does not define the root device as expected by
>>> the kernel.
>>>
>>> In addition, you will have to write a ROM block device driver. Also, I
>>> think romfs for ELKS never reached a working status.
>>>
>>> Juan
>>>
>>>
>>> On Mon, May 23, 2016 at 12:09 PM, Marc-F. LUCCA-DANIAU
>>> <mfld.fr@gmail.com> wrote:
>>>
>>> Hello,
>>>
>>> In a few words: what is the device to be used for a ROMFS root ?
>>>
>>> More: I configured ELKS as a ROM image for an embedded system, and I run
>>> it
>>> under EMU86, but I cannot figure out:
>>>
>>> 1- how to tell ELKS to read the ROMFS superblock from ROM address space?
>>> 2- how to build a ROMFS image to put in the ROM address space?
>>>
>>> All my tries end up with the well known:
>>>
>>> $ ./emu86 -w 0xe0000 -f ../../elks/elks/arch/i86/Image -x 0xe000:0x42 -i
>>>
>>> $ ./pcat `cat emu86.pts`
>>> Loading kernel image...
>>> Console: BIOS 10x115 emulating ANSI (3 virtual consoles)
>>> PC/AT class machine, inode! CPU8308K base RAM, CPUID `nd socket for in'.
>>> ELKS kernel (39008 text + 4168 data + 48648 bss)
>>> Kernel text at e062:0000, data at 90:0000 62 K of memory for user
>>> processes.
>>> ELKS network sockets
>>> TCP/IP stack by Harry Kalogirou
>>> ELKS version 0.2.0
>>> panic: VFS: Unable to mount root fs on 206D
>>> apparent call stack:
>>> Line: Addr    Parameters~~~~: ~~~~    ~~~~~~~~~~
>>>     0: 1D59 => 0000 7102 0000 0000 0000 0000 0000
>>>     1: 00B7 => 0000 0000 0000 0000 0000 0000 0000
>>>     2: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     3: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     4: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     5: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     6: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>>     7: 1048 => 0000 0000 0000 0000 0000 0000 0000
>>>     8: 0000 => CE50 0000 0000 0001 0000 6166 6C69
>>> SYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:
>>>
>>> Any suggestion ?
>>>
>>> Thanks,
>>>
>>> MFLD
>>>
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>