From: Bjorn Helgaas <bhelgaas@google.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: pmenzel@molgen.mpg.de, Joerg Roedel <joro@8bytes.org>,
Borislav Petkov <bp@alien8.de>,
linux-mm@kvack.org, x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: x86/mm: Found insecure W+X mapping at address (ptrval)/0xc00a0000
Date: Mon, 8 Oct 2018 15:08:30 -0500 [thread overview]
Message-ID: <CAErSpo5dSd7=BZFoROowLACmkKHHD0gbbRQWN3VCga3M3GepgQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1810082108570.2455@nanos.tec.linutronix.de>
On Mon, Oct 8, 2018 at 2:37 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Paul,
>
> On Fri, 5 Oct 2018, Paul Menzel wrote:
> > On 10/05/18 11:27, Thomas Gleixner wrote:
> > > If pcibios is enabled and used, need to look at the gory details of that
> > > first, then the W+X check has to exclude that region. We can't do much
> > > about that.
> >
> > That would also explain, why it only happens with the SeaBIOS payload,
> > which sets up legacy BIOS calls. Using GRUB directly as payload, no BIOS
> > calls are set up.
> >
> > Reading the Kconfig description of the PCI access mode, the BIOS should
> > only be used last.
>
> Correct. And looking at the dmesg you provided it is initialized:
>
> [ 0.441062] PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX.
> [ 0.441062] PCI: PCI BIOS revision 2.10 entry at 0xffa40, last bus=3
>
> Though I assume it's not really required, but this PCI BIOS thing is not
> really well documented and there are some obsure usage sites involved.
>
> Bjorn, do you have any insight or did you flush those memories long ago?
No, I don't. I was never really involved with PCIBIOS.
prev parent reply other threads:[~2018-10-08 20:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 6:55 x86/mm: Found insecure W+X mapping at address (ptrval)/0xc00a0000 Paul Menzel
2018-09-19 8:09 ` Thomas Gleixner
2018-09-20 7:07 ` Paul Menzel
2018-09-20 22:51 ` Thomas Gleixner
2018-09-24 21:47 ` Paul Menzel
2018-09-28 14:55 ` Thomas Gleixner
2018-10-03 21:22 ` Borislav Petkov
2018-10-04 3:11 ` Paul Menzel
2018-10-04 7:48 ` Borislav Petkov
2018-10-04 8:03 ` Joerg Roedel
2018-10-04 8:14 ` Borislav Petkov
2018-10-04 8:40 ` Paul Menzel
2018-10-04 8:49 ` Borislav Petkov
2018-10-04 8:59 ` Paul Menzel
2018-10-04 10:54 ` Borislav Petkov
2018-10-04 11:00 ` Paul Menzel
2018-10-04 11:12 ` Borislav Petkov
2018-10-04 8:43 ` Joerg Roedel
2018-10-04 8:48 ` Borislav Petkov
2018-10-05 9:27 ` Thomas Gleixner
2018-10-05 9:39 ` Paul Menzel
2018-10-08 19:37 ` Thomas Gleixner
2018-10-08 20:08 ` Bjorn Helgaas [this message]
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