Re: [Xen-devel] is_loadable_phdr

[Brad Plant <bplant@xxxxxxxxxxxx>]

On Thu, 28 Jan 2010 21:14:14 +0000
Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:

> On 28/01/2010 19:55, "Brad Plant" <bplant@xxxxxxxxxxxx> wrote:
> 
> > I'm trying to get an understanding of why a segment has to be writeable or
> > executable for xen to load it. Does anyone know why this is so?
> > 
> > Also, is it likely that this behaviour could be changed? My understanding is
> > that it's perfectly valid to have an ELF kernel with read-only segments in 
> > it.
> > Attempting to use an image with a read-only segment leads to the kernel
> > failing to boot with weird and hard to debug crashes.
> 
> Yes, we can change that. Send a patch for it.

So there's no reason not loading read-only segments then?

I've attached a patch that'll change elf_phdr_is_loadable's behaviour. It just 
adds PF_R into the mix. I don't know if this will cause some unwanted side 
effects. Unfortunately there'll be some very unhappy people if I go rebooting 
an entire physical machine at the moment.

Cheers,

Brad

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