Re: [PATCH v5 2/3] x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>

Re: [PATCH v5 2/3] x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>

[H. Peter Anvin]

On 06/13/18 14:05, Nick Desaulniers wrote:
> From: "H. Peter Anvin" <hpa@linux.intel.com>
> 
> i386 and x86-64 uses different registers for arguments; make them
> available so we don't have to #ifdef in the actual code.
> 
> Native size and specified size (q, l, w, b) versions are provided.
> 
> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

I still object to Suggested-by: here.  Sedat did a correction, which is
a Reviewed-by:, but unless I'm completely out to sea, there was no
suggestion on Sedat's part of this; and I had certainly not seen it when
I wrote the code.

	-hpa

Re: [PATCH v5 2/3] x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>

[H. Peter Anvin]

On 06/14/18 13:59, Nick Desaulniers wrote:
> On Thu, Jun 14, 2018 at 1:48 PM H. Peter Anvin <hpa@zytor.com> wrote:
>>
>> On 06/13/18 14:05, Nick Desaulniers wrote:
>>> From: "H. Peter Anvin" <hpa@linux.intel.com>
>>>
>>> i386 and x86-64 uses different registers for arguments; make them
>>> available so we don't have to #ifdef in the actual code.
>>>
>>> Native size and specified size (q, l, w, b) versions are provided.
>>>
>>> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
>>> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
>>> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>>
>> I still object to Suggested-by: here.  Sedat did a correction, which is
>> a Reviewed-by:, but unless I'm completely out to sea, there was no
>> suggestion on Sedat's part of this; and I had certainly not seen it when
>> I wrote the code.
> 
> I'm fine with changing it from a Suggested-by to a Reviewed-by.  Can
> you do that when you apply the set, or should I send a v6?
> 

I'm not handling patch mechanics for x86 at the moment.

	-hpa

Re: [PATCH v5 2/3] x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>

[Ingo Molnar]

* Nick Desaulniers <ndesaulniers@google.com> wrote:

> On Thu, Jun 14, 2018 at 5:17 PM H. Peter Anvin <hpa@zytor.com> wrote:
> >
> > On 06/14/18 13:59, Nick Desaulniers wrote:
> > > On Thu, Jun 14, 2018 at 1:48 PM H. Peter Anvin <hpa@zytor.com> wrote:
> > >>
> > >> On 06/13/18 14:05, Nick Desaulniers wrote:
> > >>> From: "H. Peter Anvin" <hpa@linux.intel.com>
> > >>>
> > >>> i386 and x86-64 uses different registers for arguments; make them
> > >>> available so we don't have to #ifdef in the actual code.
> > >>>
> > >>> Native size and specified size (q, l, w, b) versions are provided.
> > >>>
> > >>> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
> > >>> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> > >>> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > >>
> > >> I still object to Suggested-by: here.  Sedat did a correction, which is
> > >> a Reviewed-by:, but unless I'm completely out to sea, there was no
> > >> suggestion on Sedat's part of this; and I had certainly not seen it when
> > >> I wrote the code.
> > >
> > > I'm fine with changing it from a Suggested-by to a Reviewed-by.  Can
> > > you do that when you apply the set, or should I send a v6?
> > >
> >
> > I'm not handling patch mechanics for x86 at the moment.
> 
> Hi Ingo and Thomas,
> Have you had a chance to review this patch series for application?
> 
> Note that Juergen (the paravirt maintainer) acked the series:
> https://bugs.llvm.org/show_bug.cgi?id=37880
> The only issue being swapping a Suggested-by for a Reviewed-by tag for
> one commit, as above.

Could you please update the series with all suggestions and tags and send a new 
series?

Thanks,

	Ingo

Re: [PATCH v5 0/3] extern inline native_save_fl for paravirt

[Juergen Gross]

On 13/06/18 23:05, Nick Desaulniers wrote:
> paravirt depends on a custom calling convention (callee saved), but
> expects this from a static inline function that it then forces to be
> outlined. This is problematic because different compilers or flags can
> then add a stack guard that violates the calling conventions.
> 
> Uses extern inline with the out-of-line definition in assembly to
> prevent compilers from adding stack guards to the outlined version.
> 
> Other parts of the codebase overwrite KBUILD_CFLAGS, which is *extremely
> problematic* for extern inline, as the sematics are completely the
> opposite depending on what C standard is used.
> http://blahg.josefsipek.net/?p=529
> 
> Changes since v4:
>   Take Arnd's and hpa's suggestions properly feature detect gnu_inline
>   attribute to support gcc 4.1.
> 
> Changes since v3:
>   Take Joe's suggestion to hoist __inline__ and __inline out of
>   conditional block.
> 
> Changes since v2:
>   Take hpa's _ASM_ARG patch into the set in order to simplify cross
>   32b/64b x86 assembly and rebase my final patch to use it.  Apply
>   Sedat's typo fix to commit message and sign off on it. Take Joe's
>   suggestion to simplify __inline__ and __inline. Add Arnd to list of
>   folks who made helpful suggestions.
> 
> Changes since v1:
>   Prefer gnu_inline function attribute instead of explicitly setting C
>   standard compiler flag in problematic Makefiles. We should instead
>   carefully evaluate if those Makefiles should be overwriting
>   KBUILD_CFLAGS at all. Dropped the previous first two patches and added
>   a new first patch.
> 
> H. Peter Anvin (1):
>   x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>
> 
> Nick Desaulniers (2):
>   compiler-gcc.h: add gnu_inline to all inline declarations
>   x86: paravirt: make native_save_fl extern inline
> 
>  arch/x86/include/asm/asm.h      | 59 +++++++++++++++++++++++++++++++++
>  arch/x86/include/asm/irqflags.h |  2 +-
>  arch/x86/kernel/Makefile        |  1 +
>  arch/x86/kernel/irqflags.S      | 26 +++++++++++++++
>  include/linux/compiler-gcc.h    | 29 ++++++++++++----
>  5 files changed, 109 insertions(+), 8 deletions(-)
>  create mode 100644 arch/x86/kernel/irqflags.S
> 

For the series:

Acked-by: Juergen Gross <jgross@suse.com>


Juergen