[kernel-hardening] Re: [PATCH v7 1/3] x86/mm: Adapt MODULES_END based on Fixmap section size

[Ingo Molnar <mingo@kernel.org>]

* Thomas Garnier <thgarnie@google.com> wrote:

> On Thu, Mar 16, 2017 at 1:10 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > Note that asm/fixmap.h is an x86-ism that isn't present in many other
> > architectures, so this hunk will break the build.
> >
> > To make progress with these patches I've fixed it up with an ugly #ifdef
> > CONFIG_X86, but it needs a real solution instead before this can be pushed
> > upstream.
> 
> I also saw an error on x86 tip on special configuration. I found this
> new patch below to be a good solution to both.
> 
> Let me know what you think.
> 
> =====
> 
> This patch aligns MODULES_END to the beginning of the Fixmap section.
> It optimizes the space available for both sections. The address is
> pre-computed based on the number of pages required by the Fixmap
> section.
> 
> It will allow GDT remapping in the Fixmap section. The current
> MODULES_END static address does not provide enough space for the kernel
> to support a large number of processors.
> 
> Signed-off-by: Thomas Garnier <thgarnie@google.com>
> ---
> Based on next-20170308
> ---
>  Documentation/x86/x86_64/mm.txt         | 5 ++++-
>  arch/x86/include/asm/pgtable_64.h       | 1 +
>  arch/x86/include/asm/pgtable_64_types.h | 3 ++-
>  3 files changed, 7 insertions(+), 2 deletions(-)

The patch is heavily whitespace and line wrap damaged :-(

Please send a properly titled, changelogged delta patch against tip:master (or 
tip:x86/mm) to remove the CONFIG_X86 hack and fix the build bug.

Thanks,

	Ingo