svn commit: r326203 - head/sys/conf
Justin Hibbits
jrh29 at alumni.cwru.edu
Tue Nov 28 16:23:51 UTC 2017
On Tue, Nov 28, 2017 at 10:13 AM, Nathan Whitehorn
<nwhitehorn at freebsd.org> wrote:
>
>
> On 11/28/17 07:27, Justin Hibbits wrote:
>>
>> On Sat, Nov 25, 2017 at 3:45 PM, Nathan Whitehorn
>> <nwhitehorn at freebsd.org> wrote:
>>>
>>> Author: nwhitehorn
>>> Date: Sat Nov 25 21:45:51 2017
>>> New Revision: 326203
>>> URL: https://svnweb.freebsd.org/changeset/base/326203
>>>
>>> Log:
>>> Avoid emitting a PT_INTERP section for powerpc64 kernels and arrange
>>> for
>>> the first instruction to be at the start of the text segment. This
>>> allows
>>> the kernel to be booted correctly by stock kexec-lite.
>>>
>>> MFC after: 2 weeks
>>>
>>> Modified:
>>> head/sys/conf/ldscript.powerpc64
>>>
>>> Modified: head/sys/conf/ldscript.powerpc64
>>>
>>> ==============================================================================
>>> --- head/sys/conf/ldscript.powerpc64 Sat Nov 25 21:44:23 2017
>>> (r326202)
>>> +++ head/sys/conf/ldscript.powerpc64 Sat Nov 25 21:45:51 2017
>>> (r326203)
>>> @@ -10,7 +10,7 @@ SECTIONS
>>> {
>>> /* Read-only sections, merged into text segment: */
>>>
>>> - . = kernbase + SIZEOF_HEADERS;
>>> + . = kernbase;
>>> PROVIDE (begin = . - SIZEOF_HEADERS);
>>>
>>> .text :
>>> @@ -24,7 +24,10 @@ SECTIONS
>>> _etext = .;
>>> PROVIDE (etext = .);
>>>
>>> - .interp : { *(.interp) }
>>> + /* Do not emit PT_INTERP section, which confuses some loaders
>>> (kexec-lite) */
>>> + .interpX : { *(.interp) } : NONE
>>> + /DISCARD/ : { *(.interp) }
>>> +
>>> .hash : { *(.hash) }
>>> .dynsym : { *(.dynsym) }
>>> .dynstr : { *(.dynstr) }
>>>
>> This broke powerpc64 Book-E kernels. It now puts a 1MB blank space
>> ahead of the kernel data (ELF header + 1MB - sizeof(header) of 0's),
>> meaning that now the kernel needs to be loaded by uboot 1MB earlier in
>> memory, rather than straight on the 64MB boundary as it has been.
>>
>> - Justin
>>
>
> How on Earth? It doesn't do that on my system. What binutils are you using?
> -Nathan
>
This is using base binutils (2.17.50...) I don't know why it's doing
this, but readelf shows that file offset 0x0000000000100000 maps to
0xc000000000000000, and it goes from there.
- Justin
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