From: Andy Lutomirski <luto@kernel.org>
To: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
Nathan Chancellor <nathan@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, llvm@lists.linux.dev
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/Kconfig: Allow X86_X32_ABI with llvm-objcopy in some cases
Date: Tue, 5 Jul 2022 17:09:21 -0700 [thread overview]
Message-ID: <6cf4bab7-8c38-a2ee-07b9-fc95f901d2cb@kernel.org> (raw)
In-Reply-To: <20220701210437.579322-1-alex_y_xu@yahoo.ca>
On 7/1/22 14:04, Alex Xu (Hello71) wrote:
> According to the comment and commit message, there are issues compiling
> with IBT and/or compressed debug sections. Therefore, the condition
> should be restricted to when those are enabled.
This whole situation is gross. We code in the vDSO that needs to
dereference a genuinely 64-bit pointer. The x32 toolchain doesn't
understand this, so we have a massive hack using objcopy. I see a few
solutions:
1. Keep the hack alive, with further hacks like this patch.
2. Drop the x32 vDSO.
3. Drop x32.
4. Get gcc and/or clang to add actual support for this.
I admit I'm partial to solution #3. I wonder how practical #4 is.
--Andy
prev parent reply other threads:[~2022-07-06 0:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220701210437.579322-1-alex_y_xu.ref@yahoo.ca>
2022-07-01 21:04 ` [PATCH] x86/Kconfig: Allow X86_X32_ABI with llvm-objcopy in some cases Alex Xu (Hello71)
2022-07-01 21:20 ` Nathan Chancellor
2022-07-06 0:09 ` Andy Lutomirski [this message]
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