From: Jiaxun Yang <jiaxun.yang@flygoat.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org, Kees Cook <keescook@chromium.org>,
Borislav Petkov <bp@suse.de>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Fangrui Song <maskray@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] MIPS: Move kernel head into a standalone section
Date: Wed, 27 May 2020 20:05:22 +0800 [thread overview]
Message-ID: <20200527200522.23c4e86f@halation.net.flygoat.com> (raw)
In-Reply-To: <20200527115354.GC13965@alpha.franken.de>
On Wed, 27 May 2020 13:53:54 +0200
Thomas Bogendoerfer <tsbogend@alpha.franken.de> wrote:
> On Wed, May 27, 2020 at 02:34:33PM +0800, Jiaxun Yang wrote:
> > That's what already done by Arm64 and other architectures.
> > That would allow us put more things like PE headers safely into
> > the header.
> >
> > Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> > ---
> > arch/mips/kernel/head.S | 4 ++--
> > arch/mips/kernel/vmlinux.lds.S | 8 ++++++--
> > 2 files changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
> > index c7c2795837e7..8081a905a71c 100644
> > --- a/arch/mips/kernel/head.S
> > +++ b/arch/mips/kernel/head.S
> > @@ -59,6 +59,8 @@
> > #endif
> > .endm
> >
> > + __HEAD
> > +_head:
> > #ifndef CONFIG_NO_EXCEPT_FILL
> > /*
> > * Reserved space for exception handlers.
>
> I'm adding the missing piece, why this change ist broken:
>
> * Necessary for machines which link their kernels at KSEG0.
>
> by putting something in front of that will probably break platforms
> making use of "feature". If we can make sure, we don't need it
> anymore, we should first remove this and then add __HEAD part.
__HEAD is just marking the section of code.
It will not add anything to the binary.
Btw: I just noticed this patch may break relocatable kernel. I'll delay
it for next merge window.
Thanks.
>
> Thomas.
>
--
Jiaxun Yang
next prev parent reply other threads:[~2020-05-27 12:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 6:34 [PATCH v2 0/3] Buggy bootloader workaround v2 Jiaxun Yang
2020-05-27 6:34 ` [PATCH v2 1/3] MIPS: head.S: Always jump to kernel_entry at head of text Jiaxun Yang
2020-05-27 11:41 ` Thomas Bogendoerfer
2020-05-27 6:34 ` [PATCH v2 2/3] MIPS: Move kernel head into a standalone section Jiaxun Yang
2020-05-27 11:53 ` Thomas Bogendoerfer
2020-05-27 12:05 ` Jiaxun Yang [this message]
2020-05-27 13:33 ` Thomas Bogendoerfer
2020-05-27 6:34 ` [PATCH v2 3/3] MIPS: Loongson64: select NO_EXCEPT_FILL Jiaxun Yang
2020-05-27 11:47 ` Thomas Bogendoerfer
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