From: "H. Peter Anvin" <hpa@zytor.com> To: Andrew Lutomirski <luto@mit.edu>, Borislav Petkov <bp@amd64.org> Cc: Al Viro <viro@zeniv.linux.org.uk>, Linus Torvalds <torvalds@linux-foundation.org>, 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 21:05:43 -0700 [thread overview] Message-ID: <4E51D597.3060800@zytor.com> (raw) In-Reply-To: <CAObL_7HY7qFUoqtNju42=BHTR8WuuW-cL_cQh_uUfx_7gFfHRg@mail.gmail.com> Borislav, We're tracking down an issue with the way system call arguments are handled on 32 bits. We have a solution for SYSENTER but not SYSCALL; fixing SYSCALL "properly" appears to be very difficult at best. So the question is: how much overhead would it be to simply fall back to int $0x80 or some other legacy-style domain crossing instruction for 32-bit system calls on AMD64 processors? We don't ever use SYSCALL in legacy mode, so native i386 kernels are unaffected. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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From: "H. Peter Anvin" <hpa@zytor.com> To: Andrew Lutomirski <luto@mit.edu>, Borislav Petkov <bp@amd64.org> Cc: user-mode-linux-devel@lists.sourceforge.net, Richard Weinberger <richard@nod.at>, linux-kernel@vger.kernel.org, mingo@redhat.com, Al Viro <viro@zeniv.linux.org.uk>, Linus Torvalds <torvalds@linux-foundation.org> Subject: Re: [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) Date: Sun, 21 Aug 2011 21:05:43 -0700 [thread overview] Message-ID: <4E51D597.3060800@zytor.com> (raw) In-Reply-To: <CAObL_7HY7qFUoqtNju42=BHTR8WuuW-cL_cQh_uUfx_7gFfHRg@mail.gmail.com> Borislav, We're tracking down an issue with the way system call arguments are handled on 32 bits. We have a solution for SYSENTER but not SYSCALL; fixing SYSCALL "properly" appears to be very difficult at best. So the question is: how much overhead would it be to simply fall back to int $0x80 or some other legacy-style domain crossing instruction for 32-bit system calls on AMD64 processors? We don't ever use SYSCALL in legacy mode, so native i386 kernels are unaffected. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. ------------------------------------------------------------------------------ uberSVN's rich system and user administration capabilities and model configuration take the hassle out of deploying and managing Subversion and the tools developers use with it. Learn more about uberSVN and get a free download at: http://p.sf.net/sfu/wandisco-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
next prev parent reply other threads:[~2011-08-22 4:06 UTC|newest] Thread overview: 161+ 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 18:58 ` [uml-devel] " Al Viro 2011-08-18 19:12 ` Richard Weinberger 2011-08-18 19:12 ` [uml-devel] " Richard Weinberger 2011-08-18 19:19 ` Al Viro 2011-08-18 19:19 ` [uml-devel] " Al Viro 2011-08-19 4:31 ` Al Viro 2011-08-19 8:51 ` Richard Weinberger 2011-08-19 8:51 ` [uml-devel] " 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 20:14 ` [uml-devel] " Al Viro 2011-08-20 20:55 ` Richard Weinberger 2011-08-20 21:26 ` Andrew Lutomirski 2011-08-20 21:26 ` Andrew Lutomirski 2011-08-20 21:38 ` Richard Weinberger 2011-08-20 21:38 ` [uml-devel] " Richard Weinberger 2011-08-20 21:40 ` Andrew Lutomirski 2011-08-20 21:40 ` [uml-devel] " Andrew Lutomirski 2011-08-21 6:34 ` Al Viro 2011-08-21 6:34 ` [uml-devel] " 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 8:42 ` [uml-devel] " Al Viro 2011-08-21 11:24 ` Andrew Lutomirski 2011-08-21 11:24 ` [uml-devel] " Andrew Lutomirski 2011-08-21 13:37 ` Andrew Lutomirski 2011-08-21 13:37 ` [uml-devel] " Andrew Lutomirski 2011-08-21 14:51 ` Al Viro 2011-08-21 14:51 ` [uml-devel] " Al Viro 2011-08-21 14:43 ` Al Viro 2011-08-21 16:41 ` Al Viro 2011-08-21 16:41 ` [uml-devel] " Al Viro 2011-08-22 0:44 ` Andrew Lutomirski 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 ` [uml-devel] " Al Viro 2011-08-22 1:19 ` H. Peter Anvin 2011-08-22 1:19 ` [uml-devel] " H. Peter Anvin 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 1:16 ` [uml-devel] " Al Viro 2011-08-22 1:41 ` Linus Torvalds 2011-08-22 1:41 ` [uml-devel] " Linus Torvalds 2011-08-22 1:48 ` H. Peter Anvin 2011-08-22 1:48 ` [uml-devel] " H. Peter Anvin 2011-08-22 2:01 ` Andrew Lutomirski 2011-08-22 2:01 ` [uml-devel] " Andrew Lutomirski 2011-08-22 2:07 ` Al Viro 2011-08-22 2:07 ` [uml-devel] " Al Viro 2011-08-22 2:26 ` Andrew Lutomirski 2011-08-22 2:26 ` [uml-devel] " Andrew Lutomirski 2011-08-22 2:34 ` H. Peter Anvin 2011-08-22 2:34 ` [uml-devel] " H. Peter Anvin 2011-08-22 4:05 ` H. Peter Anvin [this message] 2011-08-22 4:05 ` H. Peter Anvin 2011-08-22 9:53 ` Ingo Molnar 2011-08-22 13:34 ` Andrew Lutomirski 2011-08-22 13:34 ` Andrew Lutomirski 2011-08-22 14:40 ` Borislav Petkov 2011-08-22 14:40 ` Borislav Petkov 2011-08-22 15:13 ` Al Viro 2011-08-22 15:13 ` Al Viro 2011-08-22 20:05 ` Linus Torvalds 2011-08-22 20:05 ` Linus Torvalds 2011-08-22 20:11 ` H. Peter Anvin 2011-08-22 20:11 ` H. Peter Anvin 2011-08-22 21:52 ` Andrew Lutomirski 2011-08-22 21:52 ` Andrew Lutomirski 2011-08-22 22:04 ` H. Peter Anvin 2011-08-22 22:04 ` H. Peter Anvin 2011-08-22 23:27 ` Linus Torvalds 2011-08-22 23:46 ` H. Peter Anvin 2011-08-22 23:46 ` H. Peter Anvin 2011-08-23 0:03 ` Al Viro 2011-08-23 0:03 ` Al Viro 2011-08-23 0:07 ` Al Viro 2011-08-23 0:07 ` Al Viro 2011-08-23 0:07 ` H. Peter Anvin 2011-08-23 0:07 ` H. Peter Anvin 2011-08-23 0:22 ` Linus Torvalds 2011-08-23 0:22 ` Linus Torvalds 2011-08-23 1:01 ` Al Viro 2011-08-23 1:13 ` Al Viro 2011-08-23 1:13 ` Al Viro 2011-08-23 1:59 ` Linus Torvalds 2011-08-23 1:59 ` Linus Torvalds 2011-08-23 2:59 ` Al Viro 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 16:30 ` Al Viro 2011-08-23 16:03 ` Linus Torvalds 2011-08-23 16:03 ` Linus Torvalds 2011-08-23 16:11 ` Andrew Lutomirski 2011-08-23 16:11 ` Andrew Lutomirski 2011-08-23 16:20 ` Linus Torvalds 2011-08-23 16:20 ` Linus Torvalds 2011-08-23 17:33 ` Al Viro 2011-08-23 17:33 ` Al Viro 2011-08-23 18:04 ` 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 16:53 ` Al Viro 2011-08-23 16:58 ` Richard Weinberger 2011-08-23 16:58 ` Richard Weinberger 2011-08-23 17:07 ` Al Viro 2011-08-23 17:07 ` Al Viro 2011-08-23 17:29 ` Richard Weinberger 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 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 2011-08-23 23:04 ` H. Peter Anvin 2011-08-24 21:10 ` H. Peter Anvin 2011-08-24 21:10 ` H. Peter Anvin 2011-08-23 16:48 ` Al Viro 2011-08-23 16:48 ` Al Viro 2011-08-23 17:33 ` Linus Torvalds 2011-08-23 17:33 ` Linus Torvalds 2011-08-23 21:08 ` H. Peter Anvin 2011-08-23 21:08 ` H. Peter Anvin 2011-08-23 21:20 ` Linus Torvalds 2011-08-23 21:20 ` Linus Torvalds 2011-08-23 23:04 ` H. Peter Anvin 2011-08-23 23:04 ` H. Peter Anvin 2011-08-23 19:18 ` H. Peter Anvin 2011-08-23 19:18 ` H. Peter Anvin 2011-08-23 19:24 ` Linus Torvalds 2011-08-23 19:24 ` Linus Torvalds 2011-08-23 19:26 ` H. Peter Anvin 2011-08-23 19:26 ` H. Peter Anvin 2011-08-23 19:41 ` Al Viro 2011-08-23 19:41 ` Al Viro 2011-08-23 19:43 ` Linus Torvalds 2011-08-23 19:43 ` Linus Torvalds 2011-08-23 21:17 ` Al Viro 2011-08-23 21:17 ` Al Viro 2011-08-23 1:16 ` Andrew Lutomirski 2011-08-23 1:18 ` H. Peter Anvin 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 4:11 ` [uml-devel] " H. Peter Anvin 2011-08-22 4:26 ` Al Viro 2011-08-22 4:26 ` [uml-devel] " Al Viro 2011-08-22 5:03 ` H. Peter Anvin 2011-08-22 5:03 ` [uml-devel] " H. Peter Anvin 2011-08-23 5:10 ` Andrew Lutomirski 2011-08-23 5:10 ` [uml-devel] " Andrew Lutomirski
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