svn commit: r326203 - head/sys/conf

[Justin Hibbits]

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