Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20221104124546.196077-1-ubizjak@gmail.com> <Y4U0GwlLgAuxu3WF@zn.tnic>
 <CAMzpN2jY+m5amE-6JB_eYswG2tx1aT6U3EBdYEtc-KdXSHec0A@mail.gmail.com>
 <Y4XDlWc+2OvmW7kS@zn.tnic> <CAMzpN2iTaZ87OomAQ9cJ51osmXNLFsJTZ9f4RKg6ghLqP4gy5Q@mail.gmail.com>
In-Reply-To: <CAMzpN2iTaZ87OomAQ9cJ51osmXNLFsJTZ9f4RKg6ghLqP4gy5Q@mail.gmail.com>
From:   Uros Bizjak <ubizjak@gmail.com>
Date:   Tue, 29 Nov 2022 14:26:39 +0100
Message-ID: <CAFULd4Yx=GF-5McdP6ZbwYG=12-mHx0-zb3T1QA+DdPVYkrepQ@mail.gmail.com>
Subject: Re: [PATCH] x86/boot: Remove x86_32 PIC using ebx workaround
To:     Brian Gerst <brgerst@gmail.com>
Cc:     Borislav Petkov <bp@alien8.de>, x86@kernel.org,
        linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Nov 29, 2022 at 2:24 PM Brian Gerst <brgerst@gmail.com> wrote:
>
> On Tue, Nov 29, 2022 at 3:32 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > On Mon, Nov 28, 2022 at 10:41:11PM -0500, Brian Gerst wrote:
> > > x86-64 uses a PIC register for the medium and large PIC code models,
> > > where offsets can be larger than +/- 2GB.
> >
> > Right but 64-bit is built with -mcmodel=kernel which obviously generates
> > rip-relative.
>
> Correct.  He quoted the specific part of the GCC changelog that fixed
> the issue for the 32-bit kernel, but it's not applicable to the 64-bit
> kernel.

It says so right in the summary.

Uros.