From: Stas Sergeev <stsp@list.ru>
To: Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, Denys Vlasenko <dvlasenk@redhat.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Pavel Emelyanov <xemul@parallels.com>,
Brian Gerst <brgerst@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>, Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v5 1/4] x86/signal/64: Add a comment about sigcontext->fs and gs
Date: Wed, 17 Feb 2016 13:03:12 +0300 [thread overview]
Message-ID: <56C44560.6010708@list.ru> (raw)
In-Reply-To: <20160217072122.GA19718@gmail.com>
17.02.2016 10:21, Ingo Molnar пишет:
>
> * Andy Lutomirski <luto@kernel.org> wrote:
>
>> + * If the kernel ever adds explicit fs, gs, fsbase, and gsbase
>> + * save/restore, it will most likely need to be opt-in and use
>> + * different context slots.
>
> Btw., that's not necessarily true: it could also be made opt-out, and a
> modify_ldt() or any other cleanly identifiable legacy usage/signature that is
> associated with DOSEMU might trigger the opt-out automatically as well.
But there are the new versions of dosemu that still use
"modify_ldt() or any other cleanly identifiable legacy usage/signature"
and yet wants a new functionality.
Please don't go for such an unreliable heuristic.
> I.e. behaviorally it would still keep the ABI and modern default behavior could
> still be whatever we want to make it.
You can allow glibc to deal with the opt-ins.
It has symbol versioning system AFAIK exactly for that.
next prev parent reply other threads:[~2016-02-17 10:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-16 23:09 [PATCH v5 0/4] x86: sigcontext fixes, again Andy Lutomirski
2016-02-16 23:09 ` [PATCH v5 1/4] x86/signal/64: Add a comment about sigcontext->fs and gs Andy Lutomirski
2016-02-17 7:21 ` Ingo Molnar
2016-02-17 10:03 ` Stas Sergeev [this message]
2016-02-17 11:05 ` Ingo Molnar
2016-02-17 12:10 ` [tip:x86/asm] x86/signal/64: Add a comment about sigcontext-> fs " tip-bot for Andy Lutomirski
2016-02-16 23:09 ` [PATCH v5 2/4] x86/signal/64: Fix SS if needed when delivering a 64-bit signal Andy Lutomirski
2016-02-17 12:10 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-02-16 23:09 ` [PATCH v5 3/4] x86/signal/64: Re-add support for SS in the 64-bit signal context Andy Lutomirski
2016-02-17 12:11 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-02-16 23:09 ` [PATCH v5 4/4] selftests/x86: Add tests for UC_SIGCONTEXT_SS and UC_STRICT_RESTORE_SS Andy Lutomirski
2016-02-17 12:11 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
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