[SeaBIOS] [PATCH 1/3] Add multiboot header to bios.bin.raw

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 19.05.2015 04:10, Kevin O'Connor wrote:
> On Mon, May 18, 2015 at 08:05:17PM +0000, Vladimir 'phcoder' Serbinenko wrote:
>>
> 
>> diff --git a/scripts/layoutrom.py b/scripts/layoutrom.py
>> index dd770fe..04e7efa 100755
>> --- a/scripts/layoutrom.py
>> +++ b/scripts/layoutrom.py
>> @@ -646,9 +646,10 @@ def main():
>>          entrysym = symbols['16'].get('entry_csm')
>>      else:
>>          entrysym = symbols['16'].get('reset_vector')
>> +    mb_section = symbols['32flat'].get('mb_head').section
>>      anchorsections = [entrysym.section] + [
>>          section for section in allsections
>> -        if section.name.startswith('.fixedaddr.')]
>> +        if section.name.startswith('.fixedaddr.')] + [mb_section]
>>      keepsections = findReachable(anchorsections, checkKeep, symbols)
>>      sections = [section for section in allsections if section in keepsections]
>>  
>> diff --git a/src/fw/coreboot.c b/src/fw/coreboot.c
>> index 8fd8449..6610b3a 100644
>> --- a/src/fw/coreboot.c
>> +++ b/src/fw/coreboot.c
>> @@ -551,3 +551,19 @@ cbfs_payload_setup(void)
>>          boot_add_cbfs(cfile->fhdr, desc, bootprio_find_named_rom(filename, 0));
>>      }
>>  }
>> +
>> +void VARLOW
>> +mb_head(u32 mbptr)
>> +{
>> +  asm volatile(
>> +	".align 4\n"
>> +	"mb_header:\n"
>> +	".long 0x1BADB002\n"
>> +	".long 0x00010000\n"
>> +	".long -(0x1BADB002+0x00010000)\n"
>> +	".long mb_header\n"
>> +	".long _reloc_abs_start\n"
>> +	".long 0\n"
>> +	".long 0\n"
>> +	".long entry_elf\n");
>> +}
> 
> Can this header really exist anywhere in the rom file?
It needs to be in the first 8K, aligned to 4 bytes.
>  Is 0x1BADB002
> a required signature?
> 
Yes
> If this is just a header, it should not be placed into a function, and
> it shouldn't be marked with VARLOW.
VARLOW is to get it in first 8K. 32-bit function is for easy access to
_reloc_abs_start which is address of the first byte that needs to be loaded.
>  Instead it should be placed in
> in a top-level assembler (see ASM macro) or in romlayout.S.
> 
> -Kevin
> 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 213 bytes
Desc: OpenPGP digital signature
URL: <http://www.seabios.org/pipermail/seabios/attachments/20150519/b69156c5/attachment.asc>