From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@amacapital.net>,
Andi Kleen <andi@firstfloor.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Andi Kleen <ak@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] Add a text_poke syscall v2
Date: Thu, 28 Nov 2013 00:13:05 +0100 [thread overview]
Message-ID: <20131127231305.GN32267@pd.tnic> (raw)
In-Reply-To: <CA+55aFzTppZ+uhZ+mfHYmmJ9+aboEMUQ9PUfW63BTA-z+1nWqQ@mail.gmail.com>
On Wed, Nov 27, 2013 at 03:04:41PM -0800, Linus Torvalds wrote:
> So sysexit/sysret doesn't count as a serializing instruction, no.
> But it doesn't need to, because *self*-modifying code doesn't need a
> serializing instruction, only a branch. It's only *cross*-modifying
> code that needs a serializing instruction.
>
> So the IPI is sufficient for the cross-modifying case, and the sysret
> is sufficient for the self-modifying case. And we also don't need
> to worry about "what happens if we schedule to another CPU, and
> self-modifying becomes cross-modifying", because the scheduling will
> then do the serializing instruction.
>
> So IPI for other CPU's (limited to the mm-mask) and just a system call
> for local CPU should be perfectly fine.
Cool, so basically an empty dummy syscall IPI-ed to all cores. With a
big fat comment on top.
:-)
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2013-11-27 23:13 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-26 0:37 Andi Kleen
2013-11-26 19:05 ` Andy Lutomirski
2013-11-26 19:11 ` Andi Kleen
2013-11-26 20:03 ` Linus Torvalds
2013-11-27 19:57 ` H. Peter Anvin
2013-11-27 22:02 ` H. Peter Anvin
2013-11-27 22:21 ` Andy Lutomirski
2013-11-27 22:21 ` Borislav Petkov
2013-11-27 22:24 ` H. Peter Anvin
2013-11-27 22:25 ` H. Peter Anvin
2013-11-27 22:29 ` Borislav Petkov
2013-11-27 22:31 ` H. Peter Anvin
2013-11-27 23:04 ` Linus Torvalds
2013-11-27 23:13 ` Borislav Petkov [this message]
2013-11-27 22:40 ` H. Peter Anvin
2013-11-27 23:10 ` Borislav Petkov
2013-11-27 23:20 ` H. Peter Anvin
2013-11-27 23:40 ` Borislav Petkov
2013-11-27 23:47 ` H. Peter Anvin
2013-11-27 22:41 ` Linus Torvalds
2013-11-27 22:53 ` H. Peter Anvin
2013-11-27 23:15 ` Linus Torvalds
2013-11-27 23:28 ` H. Peter Anvin
2013-11-28 2:01 ` Linus Torvalds
2013-11-28 2:10 ` H. Peter Anvin
2013-11-28 9:12 ` Jiri Kosina
2013-11-27 23:44 ` Andi Kleen
2013-11-29 18:35 ` Oleg Nesterov
2013-11-29 19:54 ` Andi Kleen
2013-11-29 20:05 ` Oleg Nesterov
2013-11-29 20:17 ` H. Peter Anvin
2013-11-29 20:35 ` Oleg Nesterov
2013-11-29 21:24 ` H. Peter Anvin
2013-11-30 14:56 ` Oleg Nesterov
2013-11-29 23:24 ` Jiri Kosina
2013-11-30 0:22 ` Linus Torvalds
2013-12-03 18:49 ` [PATCH?] uprobes: change uprobe_write_opcode() to modify the page directly Oleg Nesterov
2013-12-03 19:00 ` Linus Torvalds
2013-12-03 19:20 ` H. Peter Anvin
2013-12-03 20:01 ` Oleg Nesterov
2013-12-03 20:21 ` H. Peter Anvin
2013-12-03 20:38 ` Oleg Nesterov
2013-12-03 20:43 ` H. Peter Anvin
2013-12-03 20:54 ` Oleg Nesterov
2013-12-03 22:01 ` Linus Torvalds
2013-12-03 23:47 ` H. Peter Anvin
2013-12-04 11:30 ` Oleg Nesterov
2013-12-04 11:11 ` Oleg Nesterov
2013-12-04 16:01 ` H. Peter Anvin
2013-12-04 16:48 ` Oleg Nesterov
2013-12-04 16:54 ` H. Peter Anvin
2013-12-04 17:15 ` Linus Torvalds
2013-12-04 17:43 ` Oleg Nesterov
2013-12-05 17:23 ` Oleg Nesterov
2013-12-05 17:49 ` Borislav Petkov
2013-12-05 18:45 ` Oleg Nesterov
2013-12-04 18:32 ` H. Peter Anvin
2013-12-05 8:28 ` Jon Medhurst (Tixy)
2013-12-03 22:42 ` H. Peter Anvin
2013-12-03 19:53 ` Oleg Nesterov
2013-11-30 15:20 ` [PATCH] Add a text_poke syscall v2 Oleg Nesterov
2013-11-30 16:51 ` Oleg Nesterov
2013-11-30 17:31 ` Oleg Nesterov
2013-11-30 5:16 ` H. Peter Anvin
2013-11-30 14:52 ` Oleg Nesterov
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