[lkml]   [2006]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [Fastboot] [PATCH] x86_64: Reload CS when startup_64 is used.
    "Magnus Damm" <> writes:

    > Hi Eric,
    > On 8/22/06, Eric W. Biederman <> wrote:
    >> In long mode the %cs is largely a relic. However there are a few cases
    >> like lret where it matters that we have a valid value. Without this
    >> patch it is possible to enter the kernel in startup_64 without setting
    >> %cs to a valid value. With this patch we don't care what %cs value
    >> we enter the kernel with, so long as the cs shadow register indicates
    >> it is a privileged code segment.
    >> Thanks to Magnus Damm for finding this problem and posting the
    >> first workable patch. I have moved the jump to set %cs down a
    >> few instructions so we don't need to take an extra jump. Which
    >> keeps the code simpler.
    >> Signed-of-by: Eric W. Biederman <>
    > While at it, could you please fix up the purgatory code in kexec-tools
    > to include this fix so we can boot older versions of the kernel too?

    I guess I'm not opposed to a patch but I have some serious reservations
    about a solution that limits my address to 32bits in 64bit mode, and
    appears to break the gdt used for entering the 32bit kernel.

    I'm up way to late tonight. I just wanted to resolve the situation
    when it was clear what was going on.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2006-08-22 11:29    [W:0.022 / U:144.552 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site