From: Thomas Petazzoni via buildroot <buildroot@buildroot.org>
To: Yegor Yefremov <yegorslists@googlemail.com>
Cc: buildroot@buildroot.org, Julien Olivain <ju.o@free.fr>
Subject: Re: [Buildroot] [PATCH] package/musl: fix build for POWER10 and later
Date: Sun, 15 Nov 2026 10:48:54 +0100 [thread overview]
Message-ID: <avl_jpXx2ArJxs_D@windsurf> (raw)
In-Reply-To: <20261115065803.1426249-1-yegorslists@googlemail.com>
On Sun, Nov 15, 2026 at 07:58:03AM +0100, Yegor Yefremov wrote:
> When targeting POWER10 or POWER11, gcc generates pc-relative code by
> default, and the resulting C functions do not preserve the TOC pointer.
> musl's powerpc64 assembly calls or tail-calls C functions assuming the
> TOC-based ABI (bl without a following nop in crt_arch.h, b __dlsym in
> dlsym.s, b __setjmp_toc in setjmp.s/sigsetjmp.s), so the linker cannot
> insert the needed TOC save/restore stubs and linking libc.so fails:
>
> dlstart.c:(.text+0x24): call to `_dlstart_c' lacks nop, can't restore toc; (toc save/adjust stub)
> ld: final link failed: bad value
>
> Build musl with -mno-pcrel for POWER10 and POWER11, so musl itself is
> built as TOC-based code. Applications can still be built with
> pc-relative code and link against it.
>
> The issue has been reported upstream [1], as musl does not accept
> AI-assisted patches.
>
> This issue has been present since commit 3523e1ac79c1
> ("arch/Config.in.powerpc: add Power10 CPU type"), which made it possible
> to build musl with -mcpu=power10 (and later power11, added by commit
> da1b45dd00fd ("arch/Config.in.powerpc: add Power11 CPU type")). It
> therefore affects 2026.08 and later, including 2026.08.x.
>
> Fixes:
> https://autobuild.buildroot.org/results/1342da7c9258a93eada96f92f53a643e316ce7f6
>
> [1] https://www.openwall.com/lists/musl/2026/11/15/2
Funnily enough, I had already reported the issue to upstream musl:
https://www.openwall.com/lists/musl/2026/11/05/3
> Fixes: 3523e1ac79c15c5199a15589692e269191abd546 ("arch/Config.in.powerpc: add Power10 CPU type")
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Applied to master, thanks!
Thomas
--
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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prev parent reply other threads:[~2026-11-15 9:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-15 6:58 [Buildroot] [PATCH] package/musl: fix build for POWER10 and later Yegor Yefremov
2026-11-15 9:48 ` Thomas Petazzoni via buildroot [this message]
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