From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Lutomirski <luto@mit.edu>,
Al Viro <viro@zeniv.linux.org.uk>,
mingo@redhat.com, Richard Weinberger <richard@nod.at>,
user-mode-linux-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386)
Date: Sun, 21 Aug 2011 18:19:41 -0700 [thread overview]
Message-ID: <4E51AEAD.8040005@zytor.com> (raw)
In-Reply-To: <CA+55aFztZ=r5wa0x26KJQxvZOaQq8s2v3u50wCyJcA-Sc4g8gQ@mail.gmail.com>
On 08/21/2011 06:09 PM, Linus Torvalds wrote:
>
> Indeed. Just add an "int 0x80" instruction to the vsyscall thing, and
> you'd be done.
>
> In fact, just replace the
>
> jmp .Lenter_kernel
>
> with
>
> int 0x80
>
> and you'd be pretty much all done, no?
>
> (Ok, that's probably a huge over-simplification, but perhaps "close
> enough" to true that it would be workable)
>
Hm... I think a jump to something which adjusts %esp and invokes int
$0x80 might just work, but only for SYSENTER.
SYSCALL is different, especially since SYSCALL is legal to execute from
anywhere in userspace (and no, as we have learned already doing EIP
checking is *NOT* acceptable.)
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2011-08-22 1:20 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-18 18:58 Subject: [PATCH 00/91] pending uml patches Al Viro
2011-08-18 19:12 ` Richard Weinberger
2011-08-18 19:19 ` Al Viro
2011-08-19 4:31 ` Al Viro
2011-08-19 8:51 ` Richard Weinberger
2011-08-20 1:18 ` [RFC] weird crap with vdso on uml/i386 Al Viro
2011-08-20 15:22 ` Richard Weinberger
2011-08-20 20:14 ` Al Viro
2011-08-20 20:55 ` Richard Weinberger
2011-08-20 21:26 ` Andrew Lutomirski
2011-08-20 21:38 ` Richard Weinberger
2011-08-20 21:40 ` Andrew Lutomirski
2011-08-21 6:34 ` Al Viro
2011-08-21 8:42 ` SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) Al Viro
2011-08-21 11:24 ` Andrew Lutomirski
2011-08-21 13:37 ` Andrew Lutomirski
2011-08-21 14:51 ` Al Viro
2011-08-21 14:43 ` Al Viro
2011-08-21 16:41 ` Al Viro
2011-08-22 0:44 ` Andrew Lutomirski
2011-08-22 1:09 ` Linus Torvalds
2011-08-22 1:19 ` Al Viro
2011-08-22 1:19 ` H. Peter Anvin [this message]
2011-08-22 21:25 ` [tip:x86/urgent] x86-32, vdso: On system call restart after SYSENTER, use int $0x80 tip-bot for H. Peter Anvin
2011-08-23 23:40 ` tip-bot for H. Peter Anvin
2011-08-22 1:16 ` SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) Al Viro
2011-08-22 1:41 ` Linus Torvalds
2011-08-22 1:48 ` H. Peter Anvin
2011-08-22 2:01 ` Andrew Lutomirski
2011-08-22 2:07 ` Al Viro
2011-08-22 2:26 ` Andrew Lutomirski
2011-08-22 2:34 ` H. Peter Anvin
2011-08-22 4:05 ` H. Peter Anvin
2011-08-22 9:53 ` [uml-devel] " Ingo Molnar
2011-08-22 13:34 ` Andrew Lutomirski
2011-08-22 14:40 ` Borislav Petkov
2011-08-22 15:13 ` Al Viro
2011-08-22 20:05 ` Linus Torvalds
2011-08-22 20:11 ` H. Peter Anvin
2011-08-22 21:52 ` Andrew Lutomirski
2011-08-22 22:04 ` H. Peter Anvin
2011-08-22 23:27 ` Linus Torvalds
2011-08-22 23:46 ` H. Peter Anvin
2011-08-23 0:03 ` Al Viro
2011-08-23 0:07 ` Al Viro
2011-08-23 0:07 ` H. Peter Anvin
2011-08-23 0:22 ` Linus Torvalds
2011-08-23 1:01 ` Al Viro
2011-08-23 1:13 ` Al Viro
2011-08-23 1:59 ` Linus Torvalds
2011-08-23 2:59 ` Al Viro
2011-08-23 2:17 ` Al Viro
2011-08-23 6:15 ` Al Viro
2011-08-23 14:26 ` Borislav Petkov
2011-08-23 16:30 ` Al Viro
2011-08-23 16:03 ` Linus Torvalds
2011-08-23 16:11 ` Andrew Lutomirski
2011-08-23 16:20 ` Linus Torvalds
2011-08-23 17:33 ` Al Viro
2011-08-23 18:04 ` Al Viro
2011-08-24 12:44 ` [PATCH] x86, asm: Document some of the syscall asm glue Borislav Petkov
2011-08-23 16:22 ` [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) Borislav Petkov
2011-08-23 16:29 ` Linus Torvalds
2011-08-23 16:53 ` Al Viro
2011-08-23 16:58 ` Richard Weinberger
2011-08-23 17:07 ` Al Viro
2011-08-23 17:29 ` Richard Weinberger
2011-08-25 0:05 ` Richard Weinberger
2011-08-23 19:15 ` H. Peter Anvin
2011-08-23 20:56 ` Borislav Petkov
2011-08-23 21:06 ` H. Peter Anvin
2011-08-23 21:10 ` Borislav Petkov
2011-08-23 23:04 ` H. Peter Anvin
2011-08-24 21:10 ` H. Peter Anvin
2011-08-23 16:48 ` Al Viro
2011-08-23 17:33 ` Linus Torvalds
2011-08-23 21:08 ` H. Peter Anvin
2011-08-23 21:20 ` Linus Torvalds
2011-08-23 23:04 ` H. Peter Anvin
2011-08-23 19:18 ` H. Peter Anvin
2011-08-23 19:24 ` Linus Torvalds
2011-08-23 19:26 ` H. Peter Anvin
2011-08-23 19:41 ` Al Viro
2011-08-23 19:43 ` Linus Torvalds
2011-08-23 21:17 ` Al Viro
[not found] ` <CAObL_7FG8eFTZ4djKH0T8tbRf2h6+iOm=OXr8194nvzc+w+a9A@mail.gmail.com>
2011-08-23 1:18 ` H. Peter Anvin
2011-08-22 4:07 ` Al Viro
2011-08-22 4:11 ` H. Peter Anvin
2011-08-22 4:26 ` Al Viro
2011-08-22 5:03 ` H. Peter Anvin
2011-08-23 5:10 ` Andrew Lutomirski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4E51AEAD.8040005@zytor.com \
--to=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@mit.edu \
--cc=mingo@redhat.com \
--cc=richard@nod.at \
--cc=torvalds@linux-foundation.org \
--cc=user-mode-linux-devel@lists.sourceforge.net \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox