Hi Eric -
Sometimes a hang at this point can be down to a mismatch between
toolchain, C library and kernel about whether floating point is
implemented, emulated or absent. Early in one of the shared libraries
there are a string of saves of FP registers, and if your CPU has no FPU
and your kernel has no FPU emulation this will be terminal (and
silently so). A printk statement in the illegal instruction trap
handler would confirm this hypothesis.
Hope this helps,
Stig
On 22 Jul 2006, at 07:10, Eric Nuckols wrote:
> I googled...and googled...etc. etc.. when trying to solve the problem
> of my
> linux kernel seemingly locking or hanging when it gets to the last
> part of
> the linux init in main.c
>
> I saw lots of information and suggestions related to try /bin/sh or
> make
> sure your initrd is ok or make sure you have more than one
> session..etc.
> etc... .. and all of these topics were mostly from 2001-2003...well..
> 2006...it's here and apparently some of us haven't gotten smarter..
>
> I had this problem recently where my kernel would boot and freeze or
> hang in
> execve of /sbin/init and also of /bin/sh or /bin/bash...
>
> I debugged and debugged.. and finally thougt... why not try the default
> Kernel config for my target, the PrPmc800 from Motorola... and see
> what that
> does.. Originally, I started with the MontaVista 3.1 Pro setup for
> the
> board and it works...so I used it's Kernel .config file to configure my
> latest and greatest (at the time) 2.6.16.18 kernel thinking... well..
> this
> has to work..
>
> so.. I ended up with a kernel that semingly hang/froze/locked on the
> execve
> call in the linux init routines...
>
> guess what folks... the google searches left me just on the verge of
> giving
> up.
>
> I am here to post this info as somewhat of another answer/alternative
> to
> people in the same predicament...
>
> if you are having problems with your cross-compiled / embedded ppc
> kernel
> freezing or hanging on execve, try using the default configuration for
> your
> target when you build the kernel...
>
> in my case, I did this sort of thing and all of a sudden, my kernel was
> working:
>
> cd to kernel dir
> make distclean
> make CROSS_COMPILE=powerpc-7400-linux-gnu- prpmc800_defconfig
> make zImage.initrd
>
> etc..etc..
>
> it turns out that since I was basing my initial config off of the 2.4.x
> .config from MontaVista, my kernel didn't boot as desired...
>
> so I figured.. after all the googling and working on it that the
> default
> PrPmc800 config had to boot... why else call it the default config..
>
> so that's my story.. since then, I have copied the kernel
> dir/arch/ppc/configs/prpmc800_defconfig to a temporary file, and
> modified it
> as necessary...
>
> moral of the story... if you are cross-compiling and having problems
> where
> you hang on execve("/sbin/init") or execve("/bin/sh") or
> execve("/bin/bash")..etc... try what I did before you go crazy
> analyzing
> the initrd or the various /etc/ file configurations or any of the other
> typical bs...
>
>
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