Re: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm page tables

[Thomas Gleixner]

On Thu, 2 Nov 2017, Linus Torvalds wrote:

> On Thu, Nov 2, 2017 at 11:40 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >
> > Hmm. Not sure. IIRC you need to be able to read it to figure out where the
> > entry points are. They are at fixed offsets, but there is some voodoo out
> > there which reads the 'elf' to get to them.
> 
> That would actually be really painful.
> 
> But I *think* you're confusing it with the vdso case, which really
> does do that whole "generate ELF information for debuggers and dynamic
> linkers" thing. The vsyscall page never did that afaik, and purely
> relied on fixed addresses.

Yes, managed to confuse myself. The vsycall page has only the fixed offset
entry points at least when its in emulation mode.

Thanks,

	tglx