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Date: Wed, 24 Jun 2026 11:55:10 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
	Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
	Ard Biesheuvel <ardb@kernel.org>,
	Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev, stable@vger.kernel.org
Subject: Re: [PATCH] x86/boot/compressed: Disable jump tables for clang
Message-ID: <ajupfkcZTTxGP2dG@gmail.com>
References: <20260623-x86-boot-compressed-disable-jt-clang-v1-1-575fccd58107@kernel.org>
 <ajulLtY29HtgWokg@gmail.com>
 <20260624093848.GA48970@noisy.programming.kicks-ass.net>
 <ajuoqIk4tSV7CmFC@gmail.com>
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In-Reply-To: <ajuoqIk4tSV7CmFC@gmail.com>


* Ingo Molnar <mingo@kernel.org> wrote:


> > I'm sitting on a patch to unconditionally disable jump-tables for
> > x86_64:
> > 
> >   https://web.git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=x86/syscall
> 
> In particular:
> 
>   https://web.git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=x86/syscall&id=76612388fe7aa41a8eb88f890d451bc17255eda0

Side note: since arch/x86/boot/compressed/Makefile constructs
its own KBUILD_CFLAGS, so a change to that Makefile will still
be required to universally apply -fno-jump-tables and work
around this Clang optimization in the decompression code.

Thanks,

	Ingo