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From: Erhard Furtner <erhard_f@mailbox.org>
To: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
	"René Rebe" <rene@exactco.de>,
	linux-kbuild@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH V2] modpost: Amend ppc64 save/restfpr symnames for -Os build
Date: Wed, 26 Nov 2025 01:16:16 +0100	[thread overview]
Message-ID: <7e955a64-2fe6-4b8e-b49e-c3f827029b2b@mailbox.org> (raw)
In-Reply-To: <d69d7167-00d1-49c5-90ee-6bc0b7e8295f@kernel.org>

On 11/23/25 15:57, Christophe Leroy (CS GROUP) wrote:
> 
> 
> Le 23/11/2025 à 13:13, René Rebe a écrit :
>> Building a size optimized ppc64 kernel (-Os), gcc emits more FP
>> save/restore symbols, that the linker generates on demand into the
>> .sfpr section. Explicitly allow-list those in scripts/mod/modpost.c,
>> too. They are needed for the amdgpu in-kernel floating point support.
> 
> Would have been interested to know with which version of GCC the problem 
> started.

I can reproduce the modpost errors on GCC 15.2 and GCC 11.5.

Same kernel .config builds ok with CLANG 20.1.8 however.

> By the way you seem to fix the problem for modules, but does it also 
> work when amdgpu is in kernel ? I would have expected a need to add 
> functions in arch/powerpc/lib/crtsavres.S as well, just like following 
> commits:

If I build amdgpu statically into the kernel I don't get the modpost 
errors, the build finishes successfully. Only building amdgpu as module 
leads to these errors Rene reported.

Regards,
Erhard

      parent reply	other threads:[~2025-11-26  0:16 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-23 12:13 [PATCH V2] modpost: Amend ppc64 save/restfpr symnames for -Os build René Rebe
2025-11-23 14:57 ` Christophe Leroy (CS GROUP)
2025-11-23 15:09   ` René Rebe
2025-11-23 15:25     ` René Rebe
2025-11-26  0:16   ` Erhard Furtner [this message]

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