[U-Boot] [PATCH] elf: use program header for loading

Christian Gmeiner christian.gmeiner at gmail.com
Mon Dec 12 11:50:31 CET 2016


Sorry for the late reply.. had some days off.

>
>> The section header address is a VMA whereas the address found in
>> the program header is a physical one. With this change it is
>> possible to load and start a vx7 intel generic based image.
>>
>> $ readelf -l /tmp/vx7
>>
>> Elf file type is EXEC (Executable file)
>> Entry point 0x408000
>> There are 2 program headers, starting at offset 52
>>
>> Program Headers:
>>   Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
>>   LOAD           0x001000 0x00408000 0x00408000 0x04000 0x04000 RWE 0x1000
>>   LOAD           0x005000 0xe040c000 0x0040c000 0x583a84 0x5ccc70 RWE 0x1000
>>
>>  Section to Segment mapping:
>>   Segment Sections...
>>    00     .text.locore .data.locore
>>    01     .text .eh_frame .wrs_build_vars .data .tls_data .tls_vars .bss
>>
>> $ readelf -S /tmp/vx7
>> There are 13 section headers, starting at offset 0x588af8:
>>
>> Section Headers:
>>   [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
>>   [ 0]                   NULL            00000000 000000 000000 00      0   0  0
>>   [ 1] .text.locore      PROGBITS        00408000 001000 00011e 00  AX  0   0 16
>>   [ 2] .data.locore      PROGBITS        00409000 002000 003000 00  WA  0   0 4096
>>   [ 3] .text             PROGBITS        e040c000 005000 4802a0 00 WAX  0   0 32
>>   [ 4] .eh_frame         PROGBITS        e088c2a0 4852a0 0a1ed0 00   A  0   0  4
>>   [ 5] .wrs_build_vars   PROGBITS        e092e170 527170 000190 00  Ax  0   0  1
>>   [ 6] .data             PROGBITS        e092f000 528000 060a70 00  WA  0   0 4096
>>   [ 7] .tls_data         PROGBITS        e098fa70 588a70 000004 00   A  0   0  4
>>   [ 8] .tls_vars         PROGBITS        e098fa78 588a78 00000c 00  WA  0   0  4
>>   [ 9] .bss              NOBITS          e098faa0 588a84 0491d0 00  WA  0   0 32
>>   [10] .shstrtab         STRTAB          00000000 588a84 000074 00      0   0  1
>>   [11] .symtab           SYMTAB          00000000 588d00 056ee0 10     12 9758  4
>>   [12] .strtab           STRTAB          00000000 5dfbe0 05f48a 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)
>
> First, this is within the realm of 'bootvx' and not 'bootelf', this
> needs to be clear from the commit message.
>

Okay.. will send a V2 shortly.

>> Signed-off-by: Christian Gmeiner <christian.gmeiner at gmail.com>
>> ---
>>  cmd/elf.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/cmd/elf.c b/cmd/elf.c
>> index 5190cc6..445daa0 100644
>> --- a/cmd/elf.c
>> +++ b/cmd/elf.c
>> @@ -376,7 +376,7 @@ int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>        * binary image.
>>        */
>>       if (valid_elf_image(addr))
>> -             addr = load_elf_image_shdr(addr);
>> +             addr = load_elf_image_phdr(addr);
>
> Have you tested this with an older VxWorks image as well?  Thanks!
>

Yes.. a vx5.5 based image boots too and here is the readelf output:

$ readelf -l /tmp/vx5

Elf file type is EXEC (Executable file)
Entry point 0x308000
There are 1 program headers, starting at offset 52

Program Headers:
 Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
 LOAD           0x000060 0x00308000 0x00308000 0x3513a0 0x757860 RWE 0x20

Section to Segment mapping:
 Segment Sections...
  00     .text .data .bss
[christian at chgm-pc ~]$ readelf -S /tmp/vx5
There are 12 section headers, starting at offset 0x356580:

Section Headers:
 [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
 [ 0]                   NULL            00000000 000000 000000 00      0   0  0
 [ 1] .text             PROGBITS        00308000 000060 319b10 00 WAX  0   0 32
 [ 2] .data             PROGBITS        00621b20 319b80 037880 00  WA  0   0 32
 [ 3] .bss              NOBITS          006593a0 351400 4064c0 00  WA  0   0 16
 [ 4] .debug_aranges    PROGBITS        00000000 351400 000060 00      0   0  1
 [ 5] .debug_pubnames   PROGBITS        00000000 351460 00018b 00      0   0  1
 [ 6] .debug_info       PROGBITS        00000000 3515eb 003429 00      0   0  1
 [ 7] .debug_abbrev     PROGBITS        00000000 354a14 000454 00      0   0  1
 [ 8] .debug_line       PROGBITS        00000000 354e68 0016a4 00      0   0  1
 [ 9] .shstrtab         STRTAB          00000000 35650c 000071 00      0   0  1
 [10] .symtab           SYMTAB          00000000 356760 0440e0 10     11 8574  4
 [11] .strtab           STRTAB          00000000 39a840 03e66c 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)

greets
--
Christian Gmeiner, MSc

https://soundcloud.com/christian-gmeiner


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