Re: [Qemu-devel] Can't switch to 64bit mode at boot, how to debug?

[Goswin von Brederlow]

On Sat, Nov 17, 2012 at 11:18:03PM +0300, Max Filippov wrote:
> On Sat, Nov 17, 2012 at 11:58 PM, Max Filippov <address@hidden> wrote:
> > On Sat, Nov 17, 2012 at 9:50 PM, Goswin von Brederlow <address@hidden> 
> > wrote:
> >>         /* Enable PAE */
> >>         movl    %cr4, %eax
> >>         btsl    $5, %eax
> >>         movl    %eax, %cr4
> >
> > Interestingly with the current HEAD the code disappears after this 
> > instruction:
> 
> ...only from gdb output. xp in qemu monitor still works, looks like
> the issue here
> is with code access for gdb.
> 
> Otherwise it works for me both with the current HEAD, and with v1.1.0.
> I built your kernel like this:
> 
> gcc -I. -m32 test.S -nodefaultlibs -nostartfiles -Wl,-N -Wl,-Ttext
> -Wl,100000 -Wl,--build-id=none -o test
> 
> -- 
> Thanks.
> -- Max
> 

Args, the problem was that I used "qemu", which currently links to
qemu-system-i386 instead of "qemu-system-x86_64". A some point in the last
year the alternative setting must have reverted from x86_64 to the default
of i386.

MfG
        Goswin