[coreboot] Mohon Peak, Memtest86+ does not start
Aaron Durbin
adurbin at chromium.org
Fri Jan 23 16:47:01 CET 2015
On Fri, Jan 23, 2015 at 1:45 AM, Kuzmichev Viktor
<kuzmichevviktorv at gmail.com> wrote:
> Hello Stefan,
>
> Thank you for the tip, I'm currently looking into that. But I'm still not
> sure how to specify the load address. My guess is that I should edit the
> linking script properly to do it. By default it looks as follows
> (memtest.lds):
>
> OUTPUT_FORMAT("elf32-i386");
> OUTPUT_ARCH(i386);
>
> ENTRY(_start);
> SECTIONS {
> . = 0x10000;
> _start = . ;
> .data : {
> *(.data)
> }
> }
>
> And here is the output of 'readelf -a memtest' command:
>
> ELF Header:
> Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
> Class: ELF32
> Data: 2's complement, little endian
> Version: 1 (current)
> OS/ABI: UNIX - System V
> ABI Version: 0
> Type: EXEC (Executable file)
> Machine: Intel 80386
> Version: 0x1
> Entry point address: 0x10000
> Start of program headers: 52 (bytes into file)
> Start of section headers: 239496 (bytes into file)
> Flags: 0x0
> Size of this header: 52 (bytes)
> Size of program headers: 32 (bytes)
> Number of program headers: 1
> Size of section headers: 40 (bytes)
> Number of section headers: 3
> Section header string table index: 2
>
> Section Headers:
> [Nr] Name Type Addr Off Size ES Flg Lk
> Inf Al
> [ 0] NULL 00000000 000000 000000 00 0
> 0 0
> [ 1] .data PROGBITS 00010000 010000 02a774 00 WA 0 0
> 1
> [ 2] .shstrtab STRTAB 00000000 03a774 000011 00 0
> 0 1
> Key to Flags:
> W (write), A (alloc), X (execute), M (merge), S (strings)
> I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
> O (extra OS processing required) o (OS specific), p (processor specific)
>
> There are no section groups in this file.
>
> Program Headers:
> Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
> LOAD 0x000000 0x00000000 0x00000000 0x3a774 0x3a774 RW 0x200000
>
> Section to Segment mapping:
> Segment Sections...
> 00 .data
>
> There is no dynamic section in this file.
>
> There are no relocations in this file.
>
> The decoding of unwind sections for machine type Intel 80386 is not
> currently supported.
>
> No version information found in this file.
>
> So, the entry point is at the offset of 0x10000. But I think I should
> somehow change the 'VirtAddr'. I've tried to edit the script in different
> ways, for example, I've tried to add MEMORY command and then allocate
> certain sections to the regions as explained here:
> https://sourceware.org/binutils/docs/ld/REGION_005fALIAS.html#REGION_005fALIAS
> but haven't come to any success yet.
>
> Are there any advices you could give me? Am I even looking in the right
> direction?
Ya. You are on the right path. I just confirmed your findings locally.
What you'd like to see is VirtAddr/PhysAddr = 0x10000 as well as
offset to be 0x10000 because that would match with .data section. Also
notice that MemSiz is 0x10000 greater than the Size of the .data
section. So when this payload is loading all memory from 0x00000 to
0x10000 is filled with zeros before the start of the program at
0x10000.
I poked around in trying to relink in different ways but it kept
loading at 0. You could hexedit the memtest elf file. Apparently there
is an 'ht editor' program. However, I couldn't for the life of me
figure it out, but I was able to make it coredump trying to figure out
how to navigate it. :/
But I just found this page:
http://dwarfdump.blogspot.com/2009/08/executable-file-editor-elf-editor.html
$ hte memtest
<hit space>
Goto 'elf/program headers'. Hit <enter>
Expand 'entry 0' with <enter>
Goto 'offset'
Hit <F4>.
Make 'offset', 'virtual address', 'physical address' all to 00010000
Make 'in file size' and 'in memory size' 00027008.
Hit <F2> to save.
Hit <F10> to quit.
Those values were based on the memtest I compiled:
$ readelf -e memtest
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: Intel 80386
Version: 0x1
Entry point address: 0x10000
Start of program headers: 52 (bytes into file)
Start of section headers: 225308 (bytes into file)
Flags: 0x0
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 1
Size of section headers: 40 (bytes)
Number of section headers: 3
Section header string table index: 2
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .data PROGBITS 00010000 010000 027008 00 WA 0 0 1
[ 2] .shstrtab STRTAB 00000000 037008 000011 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00000000 0x00000000 0x37008 0x37008 RW 0x200000
Section to Segment mapping:
Segment Sections...
00 .data
After the instructions above I get the following:
$ readelf -e memtest
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: Intel 80386
Version: 0x1
Entry point address: 0x10000
Start of program headers: 52 (bytes into file)
Start of section headers: 225308 (bytes into file)
Flags: 0x0
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 1
Size of section headers: 40 (bytes)
Number of section headers: 3
Section header string table index: 2
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .data PROGBITS 00010000 010000 027008 00 WA 0 0 1
[ 2] .shstrtab STRTAB 00000000 037008 000011 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x010000 0x00010000 0x00010000 0x27008 0x27008 RW 0x200000
Section to Segment mapping:
Segment Sections...
00 .data
Notice now that we're only loading the .data section at 0x10000. I
hope that helps.
>
> Thanks in advance,
> Viktor
>
>
> On 20.01.2015 22:33, Stefan Reinauer wrote:
>>
>> * Kuzmichev Viktor <kuzmichevviktorv at gmail.com> [150120 14:31]:
>>>
>>> Hello,
>>>
>>> I'm trying to load Memtest86+ on the Mohon Peak reference board from
>>> CBFS and it fails.
>>> My primary payload is SeaBIOS. Memtest is added using cbfstool, so
>>> the layout of my ROM file is as follows:
>>>
>>> $ ./build/cbfstool build/coreboot.rom print
>>> coreboot.rom: 8192 kB, bootblocksize 1024, romsize 8388608, offset
>>> 0x600000
>>> alignment: 64 bytes, architecture: x86
>>>
>>> Name Offset Type Size
>>> cmos_layout.bin 0x600000 cmos_layout 1352
>>> fallback/romstage 0x600580 stage 26616
>>> fallback/ramstage 0x606dc0 stage 60446
>>> fallback/payload 0x615a40 payload 55799
>>> config 0x623480 raw 4323
>>> revision 0x6245c0 raw 714
>>> img/Memtest86+ 0x6248c0 payload 225028
>>> (empty) 0x65b800 null 1001368
>>> mrc.cache 0x74ffc0 (unknown) 65536
>>> cpu_microcode_blob.bin 0x760000 microcode 83968
>>> (empty) 0x774840 null 46936
>>> fsp.bin 0x77ffc0 (unknown) 372736
>>> (empty) 0x7db000 null 150424
>>>
>>> I've tried versions 4.20 and 5.01. Memtest86+ v4.20 just hangs, here
>>> is output of SeaBIOS trying to load it:
>>> Trying CBFS
>>> Booting from CBFS...
>>> Run img/Memtest86+
>>> Segment 41544144 194420 at 0xffe24920 -> 194420 at 0x00000000
>>> No compression
>>>
>>> And then nothing. Memtest86+ v5.01 goes a bit further, SeaBIOS finds
>>> its entry point:
>>> Trying CBFS
>>> Booting from CBFS...
>>> Run img/Memtest86+
>>> Segment 41544144 224972 at 0xffe24920 -> 224972 at 0x00000000
>>> No compression
>>> Calling addr 0x00010000
>>
>> It looks like in both cases memtest86+ is loaded at address 0x00000000
>> which will overwrite a bunch of memory, including the coreboot tables.
>> Looks like the memtest86+ elf binary needs to specify a load address.
>>
>> Stefan
>>
>
>
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