linux-kernel - Re: [PATCH] x86/entry/vdso32: Omit '.cfi

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Message-ID: <f6a53599-f3ba-4ed7-bf93-3fd3edb4f490@zytor.com>
Date: Fri, 23 Jan 2026 16:49:23 -0800
From: "H. Peter Anvin" <hpa@...or.com>
To: Nathan Chancellor <nathan@...nel.org>, Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org
Cc: Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
        Bill Wendling <morbo@...gle.com>,
        Justin Stitt <justinstitt@...gle.com>, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev
Subject: Re: [PATCH] x86/entry/vdso32: Omit '.cfi_offset eflags' for LLVM < 16

On 2026-01-23 15:20, Nathan Chancellor wrote:
> After commit 884961618ee5 ("x86/entry/vdso32: Remove open-coded DWARF in
> sigreturn.S"), building arch/x86/entry/vdso/vdso32/sigreturn.S with LLVM
> 15 fails with:
> 
>   <instantiation>:18:20: error: invalid register name
>    .cfi_offset eflags, 64
>                      ^
>   arch/x86/entry/vdso/vdso32/sigreturn.S:33:2: note: while in macro instantiation
>    STARTPROC_SIGNAL_FRAME 8
>    ^
> 
> Support for eflags as an argument to .cfi_offset was added in the LLVM
> 16 development cycle [1]. Only add this .cfi_offset directive if it is
> supported by the assembler to clear up the error.
> 
> Fixes: 884961618ee5 ("x86/entry/vdso32: Remove open-coded DWARF in sigreturn.S")
> Link: https://github.com/llvm/llvm-project/commit/67bd3c58c0c7389e39c5a2f4d3b1a30459ccf5b7 [1]
> Signed-off-by: Nathan Chancellor <nathan@...nel.org>

Unfortunate, but simple enough.

Acked-by: H. Peter Anvin (Intel) <hpa@...or.com>