Linux Virtualization - May 2018 - [PATCH v3 23/27] x86/modules: Adapt module loading for PIE support

Hi,

(for several patches in this series:)
The commit message is confusing.  See below.


On 05/23/2018 12:54 PM, Thomas Garnier wrote:
> Adapt module loading to support PIE relocations. Generate dynamic GOT if
> a symbol requires it but no entry exist in the kernel GOT.
                                    exists
> 
> Position Independent Executable (PIE) support will allow to extended the
                                                will allow us to extend the
> KASLR randomization range below the -2G memory limit.
Does that say "below th negative 2G memory limit"?
I don't get it.

> 
> Signed-off-by: Thomas Garnier <thgarnie at google.com>
> ---
>  arch/x86/Makefile               |   4 +
>  arch/x86/include/asm/module.h   |  11 ++
>  arch/x86/include/asm/sections.h |   4 +
>  arch/x86/kernel/module.c        | 181 +++++++++++++++++++++++++++++++-
>  arch/x86/kernel/module.lds      |   3 +
>  5 files changed, 198 insertions(+), 5 deletions(-)
>  create mode 100644 arch/x86/kernel/module.lds

Thanks,
-- 
~Randy

On Wed, May 23, 2018 at 2:27 PM Randy Dunlap <rdunlap at infradead.org>
wrote:
> Hi,
> (for several patches in this series:)
> The commit message is confusing.  See below.
Thanks for the edits, I will change the different commit messages.


> On 05/23/2018 12:54 PM, Thomas Garnier wrote:
> > Adapt module loading to support PIE relocations. Generate dynamic GOT
if
> > a symbol requires it but no entry exist in the kernel GOT.
>                                      exists
> >
> > Position Independent Executable (PIE) support will allow to extended
the
>                                                  will allow us to extend
the
> > KASLR randomization range below the -2G memory limit.
> Does that say "below th negative 2G memory limit"?
> I don't get it.
Yes, below 0xffffffff80000000 basically. I think I will just say that.


> >
> > Signed-off-by: Thomas Garnier <thgarnie at google.com>
> > ---
> >  arch/x86/Makefile               |   4 +
> >  arch/x86/include/asm/module.h   |  11 ++
> >  arch/x86/include/asm/sections.h |   4 +
> >  arch/x86/kernel/module.c        | 181
+++++++++++++++++++++++++++++++-
> >  arch/x86/kernel/module.lds      |   3 +
> >  5 files changed, 198 insertions(+), 5 deletions(-)
> >  create mode 100644 arch/x86/kernel/module.lds
> Thanks,
> --
> ~Randy


-- 
Thomas

On 05/23/2018 03:01 PM, Thomas Garnier wrote:
> On Wed, May 23, 2018 at 2:27 PM Randy Dunlap <rdunlap at
infradead.org> wrote:
> 
>> Hi,
> 
>> (for several patches in this series:)
>> The commit message is confusing.  See below.
> 
> Thanks for the edits, I will change the different commit messages.
> 
> 
> 
>> On 05/23/2018 12:54 PM, Thomas Garnier wrote:
>>> Adapt module loading to support PIE relocations. Generate dynamic
GOT if
>>> a symbol requires it but no entry exist in the kernel GOT.
> 
>>                                      exists
> 
>>>
>>> Position Independent Executable (PIE) support will allow to
extended the
> 
>>                                                  will allow us to
extend
> the
> 
>>> KASLR randomization range below the -2G memory limit.
> 
>> Does that say "below th negative 2G memory limit"?
>> I don't get it.
> 
> Yes, below 0xffffffff80000000 basically. I think I will just say that.
Yes, please, that's much better.
> 
> 
>>>
>>> Signed-off-by: Thomas Garnier <thgarnie at google.com>
>>> ---
>>>  arch/x86/Makefile               |   4 +
>>>  arch/x86/include/asm/module.h   |  11 ++
>>>  arch/x86/include/asm/sections.h |   4 +
>>>  arch/x86/kernel/module.c        | 181
+++++++++++++++++++++++++++++++-
>>>  arch/x86/kernel/module.lds      |   3 +
>>>  5 files changed, 198 insertions(+), 5 deletions(-)
>>>  create mode 100644 arch/x86/kernel/module.lds
> 
> 
>> Thanks,
>> --
>> ~Randy
> 
> 
> 

-- 
~Randy