lkml.org 
[lkml]   [2007]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    On Wed, 28 Nov 2007, Rusty Russell wrote:

    > On Wednesday 28 November 2007 05:14:47 Christoph Lameter wrote:
    > > On Tue, 27 Nov 2007, Rusty Russell wrote:
    > > > Have you considered moving x86-64's setup_per_cpu_areas into generic
    > > > code? It's a bit messier because some archs might not have set up NUMA
    > > > stuff yet, but it's logically generic...
    > >
    > > Yes that will happen later. This is just the early cleanup work. I
    > > plan to generally bring the two x86 arches in line. The pda will be
    > > folded into the per cpu area and after that its easy to do.
    >
    > Unfortunately, we tried to get rid of the x86-64 pda (like i386) but you lose
    > the ability to use the stack protection config option. That's because it
    > assumes that gs:0x68 (or something) is the stack canary; we need a YA gcc
    > change to make this gs:__builtin_stack_canary_off (where gcc can emit
    > __builtin_stack_canary_off as a weak absolute symbol, so we can override it
    > for the kernel.

    This works if you rebase the per cpu area at zero. gs:0x68 is still the
    stack canary.

    The i386 method does not work because the segment register does not
    directly point to the pda.


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-11-28 19:53    [W:0.022 / U:88.528 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site