L4Linux with L4Re and Fiasco.OC-UX

[Paul Boddie]

On Wednesday 3. April 2019 07.56.32 Adam Lackorzynski wrote:
> 
> On Thu Mar 28, 2019 at 23:28:17 +0100, Paul Boddie wrote:
> > 
> > In order to try and identify the problem, I used the following command:
> > 
> > addr2line -e ~/L4/L4Linux/l4linux/mybuild/vmlinux 0x46980b
> > 
> > This seems to indicate that the point of failure is at line 2727 in
> > arch/l4/kernel/main.c which is the start of this function:
> > 
> > int __ref L4_CV main(int argc, char **argv)
> > 
> > So, I wonder what the problem might be that leads to a crash as the main
> > function is being invoked. Have I missed anything obvious?
> 
> Guess not except that doing this on UX could be a bit adventurous
> nowadays. Which instruction is sitting at 0x46980b?

I used this command to check:

objdump -d -S ~/L4/L4Linux/l4linux/mybuild/vmlinux

Here's the instruction in context (as the third from the end):

004697f0 <main>:
{
  4697f0:       55                      push   %ebp
  4697f1:       89 e5                   mov    %esp,%ebp
  4697f3:       57                      push   %edi
  4697f4:       56                      push   %esi
        LOG_printf("%s", linux_banner);
  4697f5:       be 80 40 47 00          mov    $0x474080,%esi
{
  4697fa:       53                      push   %ebx
  4697fb:       81 ec 9c 01 00 00       sub    $0x19c,%esp
        LOG_printf("\033[34;1m======> L4Linux starting... 
<========\033[0m\n");
  469801:       c7 04 24 c8 b5 4e 00    movl   $0x4eb5c8,(%esp)
{
  469808:       8b 5d 0c                mov    0xc(%ebp),%ebx
  46980b:       65 a1 14 00 00 00       mov    %gs:0x14,%eax
  469811:       89 45 f0                mov    %eax,-0x10(%ebp)
  469814:       31 c0                   xor    %eax,%eax

So, it seems to be storing a register value into a particular segment, as far 
as I can tell. I hope this is helpful.

Paul