Re: Kernel Image Format Issue - Coldfire mcf54418 CPU Failing to Boot

[Greg Ungerer <gerg@linux-m68k.org>]

Hi Jean-Michel,

On 15/5/24 21:10, Jean-Michel Hautbois wrote:
> Hi Greg,
> 
> On 15/05/2024 12:29, Greg Ungerer wrote:
>> Hi Jean-Michel,
>>
>>
>> On 15/5/24 17:56, Jean-Michel Hautbois wrote:
>>> Hi Michael,
>>>
>>>
>>> On 14/05/2024 22:16, Michael Schmitz wrote:
>>>> Jean-Michel,
>>>>
>>>> 'BIV' is probably a bootinfo tag (Boot Info Version).
>>>
>>> Thanks, it helped me, as I read the head.S file and finally 
>>> progressed :-).
>>>
>>> When dumping my vmlinux, I can see the entry point is *not* the load 
>>> address (it was in the old one):
>>> vmlinux:     file format elf32-m68k
>>>
>>>
>>> Disassembly of section .text:
>>>
>>> 40001000 <_stext>:
>>> 40001000:    4ef9 4000 2000     jmp 40002000 <_start>
>>>      ...
>>>
>>> 40002000 <_start>:
>>> 40002000:    4e71               nop
>>> 40002002:    46fc 2700          movew #9984,%sr
>>> 40002006:    203c 0104 0100     movel #17039616,%d0
>>> 4000200c:    4e7b 0002          movec %d0,%cacr
>>> 40002010:    4e71               nop
>>>
>>> Now, when uboot starts the kernel, it is not doing anything (not sure 
>>> if it hangs or does not display anything on the console. And 
>>> EARLY_PRINTK is not valid for coldfire :-(. Not sure why, so any 
>>> guidance here would be appreciate too !
>>>
>>> I will now check my platform file but at least I am not trying to 
>>> execute an instruction "0" :-).
>>
>> Can you post your kernel .conig file?
>> Did you just start with your original 3.0.12 config and use that for 
>> 6.1.83?
> 
> No, I used a very simplified one to start.
> 
> CONFIG_NAMESPACES=y
> CONFIG_EMBEDDED=y
> CONFIG_COLDFIRE=y
> CONFIG_M5441x=y
> CONFIG_ADVANCED=y
> # CONFIG_SINGLE_MEMORY_CHUNK is not set
> CONFIG_CLOCK_FREQ=240000000
> CONFIG_STMARK2=y
> CONFIG_UBOOT=y
> CONFIG_RAMBASE=0x40000000
> CONFIG_RAMSIZE=0x8000000
> CONFIG_VECTORBASE=0x40000000
> CONFIG_KERNELBASE=0x40001000
> CONFIG_BINFMT_FLAT=y
> CONFIG_NET=y
> CONFIG_PACKET=y
> CONFIG_UNIX=y
> CONFIG_INET=y
> CONFIG_DEVTMPFS=y
> CONFIG_DEVTMPFS_MOUNT=y
> CONFIG_NETDEVICES=y
> CONFIG_SERIAL_MCF=y
> CONFIG_SERIAL_MCF_BAUDRATE=115200
> CONFIG_SERIAL_MCF_CONSOLE=y
> CONFIG_HID_A4TECH=y
> CONFIG_HID_BELKIN=y
> CONFIG_HID_CHERRY=y
> CONFIG_HID_CYPRESS=y
> CONFIG_HID_EZKEY=y
> CONFIG_HID_ITE=y
> CONFIG_HID_KENSINGTON=y
> CONFIG_HID_REDRAGON=y
> CONFIG_HID_MICROSOFT=y
> CONFIG_HID_MONTEREY=y
> CONFIG_VMLINUX_MAP=y
> CONFIG_DEBUG_MEMORY_INIT=y
> CONFIG_BOOTPARAM=y
> CONFIG_BOOTPARAM_STRING="console=ttyS1,115200"
> 
> My serial console is on UART6, so I suppose I will have to modify the 
> MCFGPIO_PAR_UART2 register in arch/m68k/coldfire/m5441x.c at the very 
> least.

Was the older 3.0.12 code base a mainline kernel, or is it a modified 
vendor version?

Regards
Greg


> JM
> 
>>
>> Regards
>> Greg
>>
>>
>>
>>> Thanks,
>>> JM
>>>
>>>>
>>>> Cheers,
>>>>
>>>>      Michael
>>>>
>>>> On 15/05/24 07:11, Jean-Michel Hautbois wrote:
>>>>> Hello,
>>>>>
>>>>> I have been on this for a long time now, and I think it is time to 
>>>>> ask for some help as the answer might be "easy" :-).
>>>>>
>>>>> I'm trying to boot an upstream Linux kernel (version 6.1.83 from 
>>>>> CIP) on a custom board which already runs an old one (3.0.12).
>>>>>
>>>>> I'm encountering an issue where the CPU fails to boot with an 
>>>>> "Unexpected exception" error when u-boot calls bootm.
>>>>>
>>>>> -> bootm
>>>>> ## Booting kernel from Legacy Image at 41000000 ...
>>>>>    Image Name:   Linux-6.1.83-cip18-rt10
>>>>>    Created:      2024-04-17   5:42:32 UTC
>>>>>    Image Type:   M68K Linux Kernel Image (uncompressed)
>>>>>    Data Size:    5684872 Bytes =  5.4 MB
>>>>>    Load Address: 40001000
>>>>>    Entry Point:  40001000
>>>>>    Checksum:  6bc7660a
>>>>>    Verifying Checksum ... OK
>>>>>    Loading Kernel Image ... OK
>>>>> OK
>>>>>
>>>>>
>>>>> *** Unexpected exception ***
>>>>> Vector Number: 5  Format: 04  Fault Status: 0
>>>>>
>>>>> PC: 40001002    SR: 00002700    SP: 4fd5fcdc
>>>>> D0: 00000000    D1: 00000003    D2: 4fdfa71c    D3: 00000000
>>>>> D4: 00000000    D5: 00000001    D6: 00000000    D7: 00000001
>>>>> A0: 00000000    A1: 4fd71494    A2: 40001000    A3: 4fdfa690
>>>>> A4: 4fd91b30    A5: 4fdf3600    A6: 4fd5fd64
>>>>>
>>>>> *** Please Reset Board! ***
>>>>>
>>>>> I tried to use different Load and Entry adress but this is not 
>>>>> having any effect.
>>>>>
>>>>> Sadly, I can't use the (very) old toolchain to build my kernel, and 
>>>>> I can't build the old kernel with the toolchain I generated. It has 
>>>>> been done with buildroot and I can provide some information if this 
>>>>> is relevant.
>>>>> To summarize:
>>>>> - It has MMU enabled
>>>>> - The cpu is passed with -mcpu=54418
>>>>> - The architecture is passed with -march=isac
>>>>>
>>>>> As the u-boot version I have can't be updated (at least not easily) 
>>>>> I need to provide a uImage, so I call mkimage for this when the 
>>>>> vmlinux file is generated.
>>>>>
>>>>> I've compared the kernel image format with an older working kernel 
>>>>> image, and it seems the issue is related to the kernel image format.
>>>>>
>>>>> ```
>>>>> $> hexdump -C uImage-3.0.12 |head
>>>>> 00000000  27 05 19 56 c6 4d 40 59  62 ac 6a be 00 2f a2 00 
>>>>> |'..V.M@Yb.j../..|
>>>>> 00000010  40 02 00 00 40 02 00 00  74 e8 ca f4 05 0c 02 00 
>>>>> |@...@...t.......|
>>>>> 00000020  4c 69 6e 75 78 2d 33 2e  30 2e 31 32 2d 72 74 33 
>>>>> |Linux-3.0.12-rt3|
>>>>> 00000030  33 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 
>>>>> |3...............|
>>>>> 00000040  60 08 42 49 56 1a 00 00  00 00 4e f9 40 30 20 00 
>>>>> |`.BIV.....N.@0 .|
>>>>> 00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 
>>>>> |................|
>>>>> *
>>>>> 00001040  4e f9 40 30 20 00 4e 56  00 00 9f fc 00 00 00 04  |N.@0 
>>>>> .NV........|
>>>>> 00001050  48 d7 00 01 20 2f 00 0c  4e 7b 00 03 4c d7 00 01  |H... 
>>>>> /..N{..L...|
>>>>> 00001060  df fc 00 00 00 04 4e 5e  4e 75 00 00 4e 75 4e 75 
>>>>> |......N^Nu..NuNu|
>>>>> ```
>>>>>
>>>>> ```
>>>>> hexdump -C output/images/uImage |head
>>>>> 00000000  27 05 19 56 ab 1d 06 74  66 1f 61 48 00 56 be 88 
>>>>> |'..V...tf.aH.V..|
>>>>> 00000010  40 00 10 00 40 00 10 00  6b c7 66 0a 05 0c 02 00 
>>>>> |@...@...k.f.....|
>>>>> 00000020  4c 69 6e 75 78 2d 36 2e  31 2e 38 33 2d 63 69 70 
>>>>> |Linux-6.1.83-cip|
>>>>> 00000030  31 38 2d 72 74 31 30 00  00 00 00 00 00 00 00 00 
>>>>> |18-rt10.........|
>>>>> 00000040  7f 45 4c 46 01 02 01 00  00 00 00 00 00 00 00 00 
>>>>> |.ELF............|
>>>>> 00000050  00 02 00 04 00 00 00 01  40 00 20 00 00 00 00 34 
>>>>> |........@. ....4|
>>>>> 00000060  00 56 bb b8 00 00 00 26  00 34 00 20 00 04 00 28 
>>>>> |.V.....&.4. ...(|
>>>>> 00000070  00 12 00 11 00 00 00 01  00 00 00 00 40 00 00 00 
>>>>> |............@...|
>>>>> 00000080  40 00 00 00 00 39 d3 d0  00 39 d3 d0 00 00 00 05 
>>>>> |@....9...9......|
>>>>> 00000090  00 00 20 00 00 00 00 01  00 39 e0 00 40 39 e0 00  |.. 
>>>>> ......9..@9..|
>>>>> ```
>>>>>
>>>>> I am a bit surprised by the information at offset 0x40. My kernel 
>>>>> is an ELF file, but the old one is a BIV file I don't even know 
>>>>> what it can be -_- !
>>>>>
>>>>> I'm happy to provide any additional information or details that 
>>>>> might be helpful in resolving this issue.
>>>>>
>>>>> Thanks in advance for any help !
>>>>> JM
>>>>>
>>>>>
>>>
>>