On Wed, 2006-05-24 at 18:56 -0400, Vivek Goyal wrote:
> On Wed, May 24, 2006 at 01:40:31PM +0900, Magnus Damm wrote:
> > kexec: Avoid overwriting the current pgd (V2)
> >
> > This patch updates the kexec code for i386 and x86_64 to avoid overwriting
> > the current pgd. For most people is overwriting the current pgd is not a big
> > problem. When kexec:ing into a new kernel that reinitializes and makes use of
> > all memory we don't care about saving state.
> >
> > But overwriting the current pgd is not a good solution in the case of kdump
> > (CONFIG_CRASH_DUMP) where we want to preserve as much state as possible when
> > a crash occurs. This patch solves the overwriting issue.
> >
> > 20060524: V2
> >
> > - Broke out architecture-specific data structures into asm/kexec.h
> > - Fixed a i386/PAE page table problem only triggering on real hardware.
> > - Moved segment handling code into the assembly routines.
>
> What's the advantage of moving segment handling code into assembly
> routines? It will only add to the fear of control code page size growing
> beyond 4K.
I have two main reasons:
- Why wrap assembler instructions in C code if you just can move them
into an already existing assembly file? Much cleaner IMO.
- I'm currently working on making kexec to work under xen/dom0. And by
moving the segment handling code into the assembly file we reduce the
amount of duplicated code.
I was concerned about the size of the assembly code too and I just
re-checked with my patches applied:
i386: 300 / 4096 bytes used
x86_64: 364 / 4096 bytes used
I'd say we have more than enough space!
Thanks,
/ magnus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
