lkml.org 
[lkml]   [2011]   [Jun]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Subjectbug: kernel 3.0-rc3 not relocatable on i386?
From
Date
Hi all,

it seems that the 3.0-rc3 kernel is not relocatable on i386. I get
warnings about jiffies being an absolute symbol, and indeed, when GRUB
loads the kernel at a non-default address, jiffies is not relocated.

In my example the kernel is configured with
CONFIG_PHYSICAL_START=0x1000000
CONFIG_PHYSICAL_ALIGN=0x200000
CONFIG_RELOCATABLE=y
and loaded at 0x200000 by GRUB.

Booting fails when checking whether the timer works, because do_timer()
increments jiffies_64, but timer_irq_works() checks jiffies. The code
looks like this:

c13daab7: 8b 3d 40 7a 39 c1 mov 0xc1397a40,%edi

but arch/x86/boot/compressed/vmlinux.relocs does not contain c13daaba.
Consequently, timer_irq_works() reads the wrong memory location and
fails, causing a panic:

kernel panic: IO-APIC + timer doesn't work! Boot with apic=debug and
send a report. Then try booting with the 'noapic' option.

Needless to say, the kernel freezes a few initcalls later when booted
with noapic, because IO-APIC worked fine, in fact. I verified that by
inserting a debugging printk() in do_timer(), and I also verified with
that printk() that the address of jiffies_64 and the address of jiffies
differ at run time.

Any idea how to fix this?

Petr Tesarik



\
 
 \ /
  Last update: 2011-06-15 10:15    [W:0.050 / U:3.824 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site