Re: CVS commit: src

[David Laight <david%l8s.co.uk@localhost>]

On Tue, Nov 03, 2009 at 05:08:19AM +0000, David Young wrote:
> Module Name:  src
> Committed By: dyoung
> Date:         Tue Nov  3 05:08:19 UTC 2009
> 
> Modified Files:
>       src/sys/arch/i386/i386: copy.S
> Added Files:
>       src/share/man/man9/man9.i386: return_address.9
>       src/sys/arch/i386/include: return.h
> 
> Log Message:
> Add return_address(9) for reading the Nth return address from the call
> stack.

And how is that supposed to be implementable ????

If the kernel is compiled without a stack frame register (%ebp)
then finding return addresses further back is ~impossible.

I wouldn't want to assume that the kernel is always compiled
using %ebp as a frame pointer - x86 has few enough registers that
freeing %ebp is probably a performance gain!

        David

-- 
David Laight: david%l8s.co.uk@localhost