lkml.org 
[lkml]   [2012]   [Dec]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v7 00/27] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G
From
On Sun, Dec 23, 2012 at 6:33 AM, H. Peter Anvin <hpa@zytor.com> wrote:
> Explanation please?
>

you have following change in the patch

/* Finally jump to run C code and to be on real kernel address
* Since we are running on identity-mapped space we have to jump
* to the full 64bit address, this is only possible as indirect
* jump. In addition we need to ensure %cs is set so we make this
- * a far return.
+ * a far jump.
*/
- movq initial_code(%rip),%rax
pushq $0 # fake return address to stop unwinder
- pushq $__KERNEL_CS # set correct cs
- pushq %rax # target address in negative space
- lretq
+ /* gas 2.22 is buggy and mis-assembles ljmpq */
+ rex64 ljmp *initial_code(%rip)

#ifdef CONFIG_HOTPLUG_CPU
/*

remove that change, AMD systems works again.

Yinghai


\
 
 \ /
  Last update: 2012-12-23 19:21    [W:0.124 / U:0.280 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site