* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 9:28 [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0 torvic9
@ 2021-06-10 10:04 ` Greg KH
2021-06-10 16:42 ` Nathan Chancellor
2021-06-10 19:20 ` Nick Desaulniers
2 siblings, 0 replies; 9+ messages in thread
From: Greg KH @ 2021-06-10 10:04 UTC (permalink / raw)
To: torvic9
Cc: linux-kernel, nathan, ndesaulniers, tglx, mingo, stable,
clang-built-linux, x86
On Thu, Jun 10, 2021 at 11:28:04AM +0200, torvic9@mailbox.org wrote:
> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
> leading to the following error message when building a LTO kernel with
> Clang-13 and LLD-13:
>
> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
> '-stack-alignment=8'. Try 'ld.lld --help'
> ld.lld: Did you mean '--stackrealign=8'?
>
> It also appears that the '-code-model' flag is not necessary anymore starting
> with LLVM-9 [2].
>
> Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>
> This is for linux-stable 5.12.
> Another patch will be submitted for 5.13 shortly (unless there are objections).
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 9:28 [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0 torvic9
2021-06-10 10:04 ` Greg KH
@ 2021-06-10 16:42 ` Nathan Chancellor
2021-06-10 18:39 ` Tor Vic
2021-06-10 19:20 ` Nick Desaulniers
2 siblings, 1 reply; 9+ messages in thread
From: Nathan Chancellor @ 2021-06-10 16:42 UTC (permalink / raw)
To: torvic9, linux-kernel, ndesaulniers, tglx, mingo
Cc: stable, clang-built-linux, x86
Hi Tor,
On 6/10/2021 2:28 AM, torvic9@mailbox.org wrote:
> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
> leading to the following error message when building a LTO kernel with
> Clang-13 and LLD-13:
>
> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
> '-stack-alignment=8'. Try 'ld.lld --help'
> ld.lld: Did you mean '--stackrealign=8'?
>
> It also appears that the '-code-model' flag is not necessary anymore starting
> with LLVM-9 [2].
>
> Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>
> This is for linux-stable 5.12.
> Another patch will be submitted for 5.13 shortly (unless there are objections).
This patch needs to be accepted into mainline first before it can go to
stable so this line needs to be removed. The rest of the description
looks good to me, good job on being descriptive!
> Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377
> [1]: https://reviews.llvm.org/D103048
> [2]: https://reviews.llvm.org/D52322
As Greg's auto-response points out, there needs to be an actual
Cc: stable@vger.kernel.org
here in the patch, rather than just cc'ing stable@vger.kernel.org
through email.
> Signed-off-by: Tor Vic <torvic9@mailbox.org>
The actual patch itself looks good and I have verified that it fixes the
build error. On the resend with the above fixed, please feel free to add:
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
> ---
> arch/x86/Makefile | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 1f2e5bf..2855a1a 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -192,8 +192,9 @@ endif
> KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
>
> ifdef CONFIG_LTO_CLANG
> -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
> - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
> +ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
> +KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
> +endif
> endif
>
> ifdef CONFIG_X86_NEED_RELOCS
>
Cheers,
Nathan
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 16:42 ` Nathan Chancellor
@ 2021-06-10 18:39 ` Tor Vic
2021-06-10 19:17 ` Nick Desaulniers
0 siblings, 1 reply; 9+ messages in thread
From: Tor Vic @ 2021-06-10 18:39 UTC (permalink / raw)
To: Nathan Chancellor, linux-kernel, ndesaulniers, tglx, mingo
Cc: stable, clang-built-linux, x86
Hi Nathan,
On 10.06.21 16:42, Nathan Chancellor wrote:
> Hi Tor,
>
> On 6/10/2021 2:28 AM, torvic9@mailbox.org wrote:
>> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been
>> dropped [1],
>> leading to the following error message when building a LTO kernel with
>> Clang-13 and LLD-13:
>>
>> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
>> '-stack-alignment=8'. Try 'ld.lld --help'
>> ld.lld: Did you mean '--stackrealign=8'?
>>
>> It also appears that the '-code-model' flag is not necessary anymore
>> starting
>> with LLVM-9 [2].
>>
>> Drop '-code-model' and make '-stack-alignment' conditional on LLD <
>> 13.0.0.
>>
>> This is for linux-stable 5.12.
>> Another patch will be submitted for 5.13 shortly (unless there are
>> objections).
>
> This patch needs to be accepted into mainline first before it can go to
> stable so this line needs to be removed. The rest of the description
> looks good to me, good job on being descriptive!
>
Thank you for explaining this.
I wasn't exactly sure how the procedure for stable was.
Does this mean that the patch should be based on 5.13?
I usually use Linus' tree mirrored at GitHub.
>> Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377
>> [1]: https://reviews.llvm.org/D103048
>> [2]: https://reviews.llvm.org/D52322
>
> As Greg's auto-response points out, there needs to be an actual
>
> Cc: stable@vger.kernel.org
>
> here in the patch, rather than just cc'ing stable@vger.kernel.org
> through email.
>
Yes I misinterpreted this in the sense of "put stable mail in CC".
So if I get this right, I should NOT put stable email in CC, but only
add the "Cc: stable@vger.kernel.org" tag above the "Signed-off-by"?
>> Signed-off-by: Tor Vic <torvic9@mailbox.org>
>
> The actual patch itself looks good and I have verified that it fixes the
> build error. On the resend with the above fixed, please feel free to add:
>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> Tested-by: Nathan Chancellor <nathan@kernel.org>
>
>> ---
>> arch/x86/Makefile | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
>> index 1f2e5bf..2855a1a 100644
>> --- a/arch/x86/Makefile
>> +++ b/arch/x86/Makefile
>> @@ -192,8 +192,9 @@ endif
>> KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
>> ifdef CONFIG_LTO_CLANG
>> -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
>> - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
>> +ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
>> +KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if
>> $(CONFIG_X86_32),4,8)
>> +endif
>> endif
>> ifdef CONFIG_X86_NEED_RELOCS
>>
>
> Cheers,
> Nathan
Thanks for your help!
Tor
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 18:39 ` Tor Vic
@ 2021-06-10 19:17 ` Nick Desaulniers
0 siblings, 0 replies; 9+ messages in thread
From: Nick Desaulniers @ 2021-06-10 19:17 UTC (permalink / raw)
To: Tor Vic
Cc: Nathan Chancellor, linux-kernel, tglx, mingo, stable,
clang-built-linux, x86
On Thu, Jun 10, 2021 at 11:39 AM Tor Vic <torvic9@mailbox.org> wrote:
>
> Hi Nathan,
>
> On 10.06.21 16:42, Nathan Chancellor wrote:
> > As Greg's auto-response points out, there needs to be an actual
> >
> > Cc: stable@vger.kernel.org
> >
> > here in the patch, rather than just cc'ing stable@vger.kernel.org
> > through email.
> >
>
> Yes I misinterpreted this in the sense of "put stable mail in CC".
> So if I get this right, I should NOT put stable email in CC, but only
> add the "Cc: stable@vger.kernel.org" tag above the "Signed-off-by"?
Yep, just above the Link: tags would be perfect. Don't worry, you'll
get the hang of it.
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 9:28 [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0 torvic9
2021-06-10 10:04 ` Greg KH
2021-06-10 16:42 ` Nathan Chancellor
@ 2021-06-10 19:20 ` Nick Desaulniers
2021-06-10 20:16 ` Tor Vic
2021-06-11 8:07 ` David Laight
2 siblings, 2 replies; 9+ messages in thread
From: Nick Desaulniers @ 2021-06-10 19:20 UTC (permalink / raw)
To: Tor Vic; +Cc: linux-kernel, nathan, tglx, mingo, stable, clang-built-linux, x86
On Thu, Jun 10, 2021 at 2:28 AM <torvic9@mailbox.org> wrote:
>
> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
> leading to the following error message when building a LTO kernel with
> Clang-13 and LLD-13:
>
> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
> '-stack-alignment=8'. Try 'ld.lld --help'
> ld.lld: Did you mean '--stackrealign=8'?
>
> It also appears that the '-code-model' flag is not necessary anymore starting
> with LLVM-9 [2].
>
> Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
Please include this additional context in v2:
```
These flags were necessary because these flags were not encoded in the
IR properly, so the link would restart optimizations without them. Now
there are properly encoded in the IR, and these flags exposing
implementation details are no longer necessary.
```
That way it doesn't sound like we're not using an 8B stack alignment
on x86; we very much are so; AMDGPU GPFs without it!
Cut the below paragraph out on v2. Thanks for the patch and keep up
the good work!
>
> This is for linux-stable 5.12.
> Another patch will be submitted for 5.13 shortly (unless there are objections).
>
> Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377
> [1]: https://reviews.llvm.org/D103048
> [2]: https://reviews.llvm.org/D52322
>
> Signed-off-by: Tor Vic <torvic9@mailbox.org>
> ---
> arch/x86/Makefile | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 1f2e5bf..2855a1a 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -192,8 +192,9 @@ endif
> KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
>
> ifdef CONFIG_LTO_CLANG
> -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
> - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
> +ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
> +KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
> +endif
> endif
>
> ifdef CONFIG_X86_NEED_RELOCS
> --
> 2.32.0
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 19:20 ` Nick Desaulniers
@ 2021-06-10 20:16 ` Tor Vic
2021-06-10 20:40 ` Nathan Chancellor
2021-06-11 8:07 ` David Laight
1 sibling, 1 reply; 9+ messages in thread
From: Tor Vic @ 2021-06-10 20:16 UTC (permalink / raw)
To: Nick Desaulniers
Cc: linux-kernel, nathan, tglx, mingo, stable, clang-built-linux, x86
On 10.06.21 19:20, Nick Desaulniers wrote:
> On Thu, Jun 10, 2021 at 2:28 AM <torvic9@mailbox.org> wrote:
>>
>> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
>> leading to the following error message when building a LTO kernel with
>> Clang-13 and LLD-13:
>>
>> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
>> '-stack-alignment=8'. Try 'ld.lld --help'
>> ld.lld: Did you mean '--stackrealign=8'?
>>
>> It also appears that the '-code-model' flag is not necessary anymore starting
>> with LLVM-9 [2].
>>
>> Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>
> Please include this additional context in v2:
> ```
> These flags were necessary because these flags were not encoded in the
> IR properly, so the link would restart optimizations without them. Now
> there are properly encoded in the IR, and these flags exposing
> implementation details are no longer necessary.
> ```
> That way it doesn't sound like we're not using an 8B stack alignment
> on x86; we very much are so; AMDGPU GPFs without it!
>
Will do so.
Does this have to be a v2 (with a "changes from v1" info) or just a
resend? It is based on mainline now and the line numbers have changed.
> Cut the below paragraph out on v2. Thanks for the patch and keep up
> the good work!
>
>>
>> This is for linux-stable 5.12.
>> Another patch will be submitted for 5.13 shortly (unless there are objections).
>>
>> Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377
>> [1]: https://reviews.llvm.org/D103048
>> [2]: https://reviews.llvm.org/D52322
>>
>> Signed-off-by: Tor Vic <torvic9@mailbox.org>
>> ---
>> arch/x86/Makefile | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
>> index 1f2e5bf..2855a1a 100644
>> --- a/arch/x86/Makefile
>> +++ b/arch/x86/Makefile
>> @@ -192,8 +192,9 @@ endif
>> KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
>>
>> ifdef CONFIG_LTO_CLANG
>> -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
>> - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
>> +ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
>> +KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
>> +endif
>> endif
>>
>> ifdef CONFIG_X86_NEED_RELOCS
>> --
>> 2.32.0
>
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 20:16 ` Tor Vic
@ 2021-06-10 20:40 ` Nathan Chancellor
0 siblings, 0 replies; 9+ messages in thread
From: Nathan Chancellor @ 2021-06-10 20:40 UTC (permalink / raw)
To: Tor Vic, Nick Desaulniers
Cc: linux-kernel, tglx, mingo, stable, clang-built-linux, x86
On 6/10/2021 1:16 PM, Tor Vic wrote:
>
>
> On 10.06.21 19:20, Nick Desaulniers wrote:
>> On Thu, Jun 10, 2021 at 2:28 AM <torvic9@mailbox.org> wrote:
>>>
>>> Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
>>> leading to the following error message when building a LTO kernel with
>>> Clang-13 and LLD-13:
>>>
>>> ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
>>> '-stack-alignment=8'. Try 'ld.lld --help'
>>> ld.lld: Did you mean '--stackrealign=8'?
>>>
>>> It also appears that the '-code-model' flag is not necessary anymore starting
>>> with LLVM-9 [2].
>>>
>>> Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>>
>> Please include this additional context in v2:
>> ```
>> These flags were necessary because these flags were not encoded in the
>> IR properly, so the link would restart optimizations without them. Now
>> there are properly encoded in the IR, and these flags exposing
>> implementation details are no longer necessary.
>> ```
>> That way it doesn't sound like we're not using an 8B stack alignment
>> on x86; we very much are so; AMDGPU GPFs without it!
>>
>
> Will do so.
> Does this have to be a v2 (with a "changes from v1" info) or just a
> resend? It is based on mainline now and the line numbers have changed.
Yes, this should be a v2 because the commit message changed. It would be
considered a resend if nothing changed and the patch just needed to be
picked up rather than re-reviewed.
Cheers,
Nathan
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
2021-06-10 19:20 ` Nick Desaulniers
2021-06-10 20:16 ` Tor Vic
@ 2021-06-11 8:07 ` David Laight
1 sibling, 0 replies; 9+ messages in thread
From: David Laight @ 2021-06-11 8:07 UTC (permalink / raw)
To: 'Nick Desaulniers', Tor Vic
Cc: linux-kernel, nathan, tglx, mingo, stable, clang-built-linux, x86
From: Nick Desaulniers
> Sent: 10 June 2021 20:21
>
> On Thu, Jun 10, 2021 at 2:28 AM <torvic9@mailbox.org> wrote:
> >
> > Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
> > leading to the following error message when building a LTO kernel with
> > Clang-13 and LLD-13:
> >
> > ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
> > '-stack-alignment=8'. Try 'ld.lld --help'
> > ld.lld: Did you mean '--stackrealign=8'?
> >
> > It also appears that the '-code-model' flag is not necessary anymore starting
> > with LLVM-9 [2].
> >
> > Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>
> Please include this additional context in v2:
> ```
> These flags were necessary because these flags were not encoded in the
> IR properly, so the link would restart optimizations without them. Now
> there are properly encoded in the IR, and these flags exposing
> implementation details are no longer necessary.
> ```
> That way it doesn't sound like we're not using an 8B stack alignment
> on x86; we very much are so; AMDGPU GPFs without it!
Actually, give that LTO is still 'experimental' is it worth just
removing the flags and requiring clang-13 for LTO builds?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply [flat|nested] 9+ messages in thread