lkml.org 
[lkml]   [2018]   [Mar]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 14/15] x86/fsgsbase/64: Support legacy behavior when FS/GS updated by ptracer
Date
On 3/21/18, 18:41, "Andy Lutomirski" <luto@kernel.org> wrote:
> mov to gs changes GSBASE even if GS was unchanged.
In GDB, ptrace (syscall) doesn't happen when FS/GS unchanged as
its (context) cache seems to be first checked. This does not allow to
preserve GSBASE as you know.

> But it's not clear to me that you've identified any case where
> emulating this behavior is useful.
One argument I heard is (if debugging a legacy application) user
might want to (indirectly) access LDT during inferior call and this
mov to fs/gs has been useful (maybe needed).


\
 
 \ /
  Last update: 2018-03-22 16:46    [W:0.127 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site