From: "Hou Wenlong" <houwenlong.hwl@antgroup.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: linux-kernel@vger.kernel.org, Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Darren Hart <dvhart@infradead.org>,
Andy Shevchenko <andy@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"moderated list:XEN HYPERVISOR X86"
<xen-devel@lists.xenproject.org>,
"open list:X86 PLATFORM DRIVERS - ARCH"
<platform-driver-x86@vger.kernel.org>
Subject: Re: [PATCH 1/2] x86/xen/pvh: Set up percpu for stack canary in 32-bit kernel entry
Date: Tue, 24 Oct 2023 10:33:28 +0800 [thread overview]
Message-ID: <20231024023328.GA29837@k08j02272.eu95sqa> (raw)
In-Reply-To: <CAHp75VeXiOprRDNakewo2iSe==EeLUxfxuPYS3R+ZsY2KDmQBQ@mail.gmail.com>
On Mon, Oct 23, 2023 at 08:02:02PM +0800, Andy Shevchenko wrote:
> On Mon, Oct 23, 2023 at 12:10 PM Hou Wenlong
> <houwenlong.hwl@antgroup.com> wrote:
> >
> > In a 32-bit SMP kernel, the stack canary is a percpu variable accessed
> > as %fs:__stack_chk_guard. However, the ABI for PVH entry does not
> > specify the %fs register state. It currently works because the initial
> > %fs register is 0x10 for QEMU, which is the same as $PVH_DS_SEL.
>
> > %However, for added safety, the percpu should be set up explicitly
> > %before calling xen_prepare_pvh(), which accesses the stack canary.
>
> Stray leading % in two lines above.
>
Oh, sorry for that. It was added by mistake by my editor, and I didn't
carefully review it before sending.
Thanks!
> --
> With Best Regards,
> Andy Shevchenko
next prev parent reply other threads:[~2023-10-24 2:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-23 9:09 [PATCH 0/2] x86/xen/pvh: Clean up stack canary setup in PVH entry Hou Wenlong
2023-10-23 9:09 ` [PATCH 1/2] x86/xen/pvh: Set up percpu for stack canary in 32-bit kernel entry Hou Wenlong
2023-10-23 12:02 ` Andy Shevchenko
2023-10-24 2:33 ` Hou Wenlong [this message]
2023-10-23 9:09 ` [PATCH 2/2] x86/xen/pvh: Use fixed_percpu_data to set up GS base Hou Wenlong
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