From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: cortex-m support?
Date: Mon, 12 Dec 2016 20:48:40 -0500 [thread overview]
Message-ID: <20161213014840.GT1555@brightrain.aerifal.cx> (raw)
In-Reply-To: <a3a096d4-2426-4f7e-6212-222f0b64a6ca@landley.net>
On Mon, Dec 12, 2016 at 06:29:13PM -0600, Rob Landley wrote:
>
>
> On 12/08/2016 03:01 PM, Rich Felker wrote:
> > On Thu, Dec 08, 2016 at 01:10:11PM -0600, Rob Landley wrote:
> >> On 12/07/2016 07:16 PM, Rich Felker wrote:
> >>> On Wed, Dec 07, 2016 at 06:55:56PM -0600, Rob Landley wrote:
> >>>> Not sure where you get the relevant gcc patch...
> >>>
> >>> I have links to the repos somewhere; the problem is that they're
> >>> forked from a fairly old gcc version (although not nearly as bad as
> >>> sh-fdpic; I think it's 4.8 or so)
> >>
> >> https://github.com/mickael-guene/gcc has a 5.2 branch and "master"
> >> updated 20 hours ago, although I'm not sure how much of master updating
> >> is an automatic tracking branch and how much is the account owner
> >> updating things.
> >
> > Excellent! That's new since I last communicated with him.
>
> In theory, what you do is follow the instructions in:
>
> https://github.com/mickael-guene/fdpic_manifest
OK, I'll take a look.
> Which uses repo to download the github repositories, and then has a
> build.sh. In practice, I'm not sure what branches that uses to build
> said toolchain.
>
> However, this would give you a uClibc-based cortex-m-fdpic toolchain you
> could then swap musl into.
Just diffing the tree and dropping the patch in musl-cross-make is
going to be a much faster path to getting something reproducible and
testable.
> It also has a lsit of kernel patches that
> theoretically work against vanilla, but you don't have a board for that. :)
Can you get me (instructions for building) a kernel that boots on qemu
but has the fdpic-support patches for arm? The main patch hunk that'll
be needed is the part in signal handler invocation that uses the
function pointer as either a code address or a function descriptor.
BTW, upstreaming this patch without an old pending kernel change I
still need to submit will introduce a CVE-worthy vulnerability on all
ARM systems. :-)
> I did poke you over the summer about running cortex-m binflt binaries
> under qemu application emulation (works fine). I dunno if it supports
> the fdpic loader or not, building this toolchain to find out. If not,
> it's got an emulator there too but I haven't poked at it yet...
It can load fdpic as normal ELF just fine, but signal handlers will
crash if it doesn't treat the application-passed function pointer as a
function descriptor. Fixing this should just be a several-line patch
to qemu if nobody already did it.
Rich
next prev parent reply other threads:[~2016-12-13 1:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 5:52 Rob Landley
2016-12-07 15:29 ` Szabolcs Nagy
2016-12-07 15:35 ` Szabolcs Nagy
2016-12-08 0:55 ` Rob Landley
2016-12-08 1:16 ` Rich Felker
2016-12-08 19:10 ` Rob Landley
2016-12-08 21:01 ` Rich Felker
2016-12-08 22:36 ` Rob Landley
2016-12-13 0:29 ` Rob Landley
2016-12-13 1:48 ` Rich Felker [this message]
2016-12-20 4:23 ` Rich Felker
2016-12-07 20:19 ` Rob Landley
2016-12-08 21:11 ` Rich Felker
2016-12-09 6:33 ` Rich Felker
[not found] ` <20161208211116.GO1555-C3MtFaGISjmo6RMmaWD+6Sb1p8zYI1N1@public.gmane.org>
2016-12-15 18:34 ` [musl] " Rob Landley
[not found] ` <7bfe2625-725d-d1bb-7177-f2d31ce09e9c-VoJi6FS/r0vR7s880joybQ@public.gmane.org>
2016-12-15 18:51 ` Waldemar Brodkorb
2016-12-20 7:18 ` [Buildroot] " Rob Landley
[not found] ` <48fb6c09-9dcb-e563-dc2d-f30062c5fceb-VoJi6FS/r0vR7s880joybQ@public.gmane.org>
2016-12-20 8:26 ` Thomas Petazzoni
[not found] ` <20161220092600.2ca96088-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2016-12-20 18:17 ` Rob Landley
2016-12-21 6:18 ` [musl] " Waldemar Brodkorb
[not found] ` <20161221061853.GB2915-zdp6y753eiWHneL7xjqqhBsWhVFi+jh/@public.gmane.org>
2016-12-27 22:03 ` Rob Landley
2016-12-18 0:29 ` Rich Felker
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