From: "Dmitry V. Levin" <ldv@altlinux.org>
To: Ivan Zakharyaschev <imz@altlinux.org>
Cc: bug-gnulib@gnu.org, Andrey Savchenko <bircoph@altlinux.org>,
Bruno Haible <bruno@clisp.org>
Subject: Re: [RFC PATCH] test-c-stack2.sh: skip if the platform sent SIGILL on an invalid address.
Date: Sat, 29 Dec 2018 16:54:41 +0300 [thread overview]
Message-ID: <20181229135441.GD21197@altlinux.org> (raw)
In-Reply-To: <alpine.LFD.2.20.1812280431490.6081@imap.altlinux.org>
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On Fri, Dec 28, 2018 at 05:23:09PM +0300, Ivan Zakharyaschev wrote:
> Hi Bruno,
>
> On Thu, 20 Dec 2018, Bruno Haible wrote:
>
> > > + # E2K (elbrus) systems send SIGILL on an access to an invalid address.
> >
> > This is a bug in the system. Access of an invalid address ought to produce a
> > SIGSEGV or SIGBUS.
> >
> > 'elbrus' is not an important OS so far, for which it would be worth adding
> > workarounds in the gnulib source.
> > Is it still in development? -> If so, please fix that bug.
> > Or is it a museum system? -> If so, just bear with the test failure.
>
> Of these descriptions, "system in development" is the one which suits
> Linux/E2k better. The port to E2K (MCST Elbrus general purpose hardware
> architecture) is quite mature, but not yet released publicly.
>
> As for the SIGILL peculiarity, it has a reason in the Elbrus architecture.
> AFAIU, a different protection mechanism comes into play here. It is based
> on tagging values/memory: if an attempt is made to use a value in a way
> which contradicts its tag, then the "illegal operand" condition arises.
> Namely, a "load" instruction can expect a certain tag, and then there can
> be a mismatch between the assumptions of the code and the actual value
> and its tag.
No, this particular case (++*argv[argc]) has nothing to do with tagged memory,
I hope Ivan will share his findings here.
--
ldv
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next prev parent reply other threads:[~2018-12-29 14:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-15 12:50 [RFC PATCH] test-c-stack2.sh: skip if the platform sent SIGILL on an invalid address Ivan Zakharyaschev
2018-12-20 2:24 ` Bruno Haible
2018-12-28 14:23 ` Ivan Zakharyaschev
2018-12-29 11:17 ` Bruno Haible
2018-12-29 11:31 ` Andrey Savchenko
2018-12-29 14:03 ` Bruno Haible
2018-12-29 14:31 ` Dmitry V. Levin
2018-12-29 14:54 ` Bruno Haible
2018-12-29 15:03 ` Ivan Zakharyaschev
2018-12-29 16:30 ` Dmitry V. Levin
2018-12-29 20:13 ` Ivan Zakharyaschev
2018-12-30 4:49 ` Bruno Haible
2018-12-29 13:54 ` Dmitry V. Levin [this message]
2018-12-29 15:15 ` Ivan Zakharyaschev
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