Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Andy Lutomirski]

On Tue, Sep 22, 2015 at 11:51 AM, James Forcier <csssuf@csssuf.net> wrote:
> Exporting cpu_tlbstate as a GPL symbol was introduced in 1e02ce4c; however, this
> breaks non-GPL modules which need to link against it, particularly the AMD
> Catalyst drivers.

What is AMD Catalyst doing with cpu_tlbstate?

--Andy

>
> Signed-off-by: James Forcier <csssuf@csssuf.net>
> ---
>  arch/x86/mm/init.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index 1d8a83d..94be56b 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -742,7 +742,7 @@ DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
>  #endif
>         .cr4 = ~0UL,    /* fail hard if we screw up cr4 shadow initialization */
>  };
> -EXPORT_SYMBOL_GPL(cpu_tlbstate);
> +EXPORT_SYMBOL(cpu_tlbstate);
>
>  void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
>  {
> --
> 2.4.6
>



-- 
Andy Lutomirski
AMA Capital Management, LLC

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Thomas Gleixner]

On Tue, 22 Sep 2015, Andy Lutomirski wrote:
> On Tue, Sep 22, 2015 at 11:51 AM, James Forcier <csssuf@csssuf.net> wrote:
> > Exporting cpu_tlbstate as a GPL symbol was introduced in 1e02ce4c; however, this
> > breaks non-GPL modules which need to link against it, particularly the AMD
> > Catalyst drivers.
> 
> What is AMD Catalyst doing with cpu_tlbstate?

Fiddling with it behind the kernels back. Out of tree graphic drivers
always have their special needs. Just lookup the discussions about
unexporting init_mm ....

Thanks,

	tglx

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Andy Lutomirski]

On Sep 22, 2015 11:58 AM, "Thomas Gleixner" <tglx@linutronix.de> wrote:
>
> On Tue, 22 Sep 2015, Andy Lutomirski wrote:
> > On Tue, Sep 22, 2015 at 11:51 AM, James Forcier <csssuf@csssuf.net> wrote:
> > > Exporting cpu_tlbstate as a GPL symbol was introduced in 1e02ce4c; however, this
> > > breaks non-GPL modules which need to link against it, particularly the AMD
> > > Catalyst drivers.
> >
> > What is AMD Catalyst doing with cpu_tlbstate?
>
> Fiddling with it behind the kernels back. Out of tree graphic drivers
> always have their special needs. Just lookup the discussions about
> unexporting init_mm ....

Look for kcl_mem_pat_setup here:

https://github.com/kolasa/fglrx-13.152/blob/master/firegl_public.c

I can't NAK this patch hard enough.  The correct fix is for fglrx to
delete all of the offending code and just use ioremap_wc (which is a
plain old EXPORT_SYMBOL).  We've supported ioremap_wc properly for
*years*.

My personal view is that non-GPL modules are awful things to do, are
so bloody annoying for their (paying!) users that I'm amazed that
anyone puts up with them, but are nonetheless things that we shouldn't
go out of our way to break.  But for $*!&'s sake, we maybe should go
out of our way to prevent utter bovine excrement* like the PAT hack in
there from working.

--Andy, who is *really* looking forward to either Nvidia releasing
signed firmware blobs or Intel releasing a reasonable new integrated
GPU chip so he can stop using the nvidia binary driver.

* This is apparently the new polite term for it.

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Thomas Gleixner]

On Thu, 24 Sep 2015, Andy Lutomirski wrote:
> On Sep 22, 2015 11:58 AM, "Thomas Gleixner" <tglx@linutronix.de> wrote:
> >
> > On Tue, 22 Sep 2015, Andy Lutomirski wrote:
> > > On Tue, Sep 22, 2015 at 11:51 AM, James Forcier <csssuf@csssuf.net> wrote:
> > > > Exporting cpu_tlbstate as a GPL symbol was introduced in 1e02ce4c; however, this
> > > > breaks non-GPL modules which need to link against it, particularly the AMD
> > > > Catalyst drivers.
> > >
> > > What is AMD Catalyst doing with cpu_tlbstate?
> >
> > Fiddling with it behind the kernels back. Out of tree graphic drivers
> > always have their special needs. Just lookup the discussions about
> > unexporting init_mm ....
> 
> Look for kcl_mem_pat_setup here:
> 
> https://github.com/kolasa/fglrx-13.152/blob/master/firegl_public.c

I stopped looking at this line:

MODULE_LICENSE("GPL\0Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");
 
Thanks,

	tglx

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Borislav Petkov]

On Sun, Sep 27, 2015 at 12:46:28PM +0200, Thomas Gleixner wrote:
> > https://github.com/kolasa/fglrx-13.152/blob/master/firegl_public.c
> 
> I stopped looking at this line:
> 
> MODULE_LICENSE("GPL\0Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");

"GPL" *and* "Proprietary"??!

How does that even work?

Oh, that depends on the kernel version:

#if LINUX_VERSION_CODE < KERNEL_VERSION(3,19,0)
MODULE_LICENSE("Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");
#else
MODULE_LICENSE("GPL\0Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");
#endif

With that '\0' string terminator in there?! WTF now?!

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

Re: [PATCH] x86/mm: Export cpu_tlbstate as non-GPL symbol

[Richard Weinberger]

On Sun, Sep 27, 2015 at 1:28 PM, Borislav Petkov <bp@alien8.de> wrote:
> #if LINUX_VERSION_CODE < KERNEL_VERSION(3,19,0)
> MODULE_LICENSE("Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");
> #else
> MODULE_LICENSE("GPL\0Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY");
> #endif
>
> With that '\0' string terminator in there?! WTF now?!

AFACT this gem is not part of the official AMD Catalyst driver.

-- 
Thanks,
//richard