From: Arvind Sankar <nivedita@alum.mit.edu>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86/cmdline: Disable jump tables for cmdline.c
Date: Mon, 21 Dec 2020 16:23:00 -0500 [thread overview]
Message-ID: <X+ESNP6HdYQpd7g3@rani.riverdale.lan> (raw)
In-Reply-To: <CAKwvOdm8qUpueOdO7e-rQotO5UynrgU2TZ9DEe=O4f9eU5EY0g@mail.gmail.com>
On Mon, Dec 21, 2020 at 11:14:39AM -0800, Nick Desaulniers wrote:
> On Wed, Sep 2, 2020 at 7:31 PM Arvind Sankar <nivedita@alum.mit.edu> wrote:
> >
> > When CONFIG_RETPOLINE is disabled, Clang uses a jump table for the
> > switch statement in cmdline_find_option (jump tables are disabled when
> > CONFIG_RETPOLINE is enabled). This function is called very early in boot
> > from sme_enable() if CONFIG_AMD_MEM_ENCRYPT is enabled. At this time,
>
> Hi Arvind, sorry I missed this when you first sent it. I'm going
> through and mass deleting my inbox (email bankruptcy) but noticed
> this. I couldn't reproduce jump tables in cmdline_find_option with
> CONFIG_RETPOLINE disabled but CONFIG_AMD_MEM_ENCRYPT on today's
> linux-next. Can you please confirm that this is still an issue? I will
> reread the disassembly, but it looks like a bunch of cmp/test+jumps.
>
The patch got merged and is in v5.10 -- are you testing with it reverted
or just plain linux-next?
next prev parent reply other threads:[~2020-12-21 21:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 2:30 Arvind Sankar
2020-09-03 9:00 ` [tip: x86/urgent] " tip-bot2 for Arvind Sankar
2020-12-21 19:14 ` [PATCH] " Nick Desaulniers
2020-12-21 21:23 ` Arvind Sankar [this message]
2020-12-21 21:40 ` Nick Desaulniers
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