From: Cyrill Gorcunov <gorcunov@gmail.com> To: Andy Lutomirski <luto@amacapital.net> Cc: Dmitry Safonov <dsafonov@virtuozzo.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Dmitry Safonov <0x7f454c46@gmail.com>, Adam Borowski <kilobyte@angband.pl>, "linux-mm@kvack.org" <linux-mm@kvack.org>, Andrei Vagin <avagin@gmail.com>, Borislav Petkov <bp@suse.de>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de> Subject: [Q] Figuring out task mode Date: Tue, 21 Mar 2017 21:05:25 +0300 [thread overview] Message-ID: <20170321180525.GC21564@uranus.lan> (raw) In-Reply-To: <CALCETrXoxRBTon8+jrYcbruYVUZASwgd-kzH-A96DGvT7gLXVA@mail.gmail.com> /I renamed the mail's subject/ On Tue, Mar 21, 2017 at 10:45:57AM -0700, Andy Lutomirski wrote: > >> + task_pt_regs(current)->orig_ax |= __X32_SYSCALL_BIT; > >> current->thread.status &= ~TS_COMPAT; > > > > Hi! I must admit I didn't follow close the overall series (so can't > > comment much here :) but I have a slightly unrelated question -- is > > there a way to figure out if task is running in x32 mode say with > > some ptrace or procfs sign? > > You should be able to figure out of a *syscall* is x32 by simply > looking at bit 30 in the syscall number. (This is unlike i386, which > is currently not reflected in ptrace.) Yes, syscall number will help but from criu perpspective (until Dima's patches are merged into mainlie) we need to figure out if we can dump x32 tasks without running parasite code inside, ie via plain ptrace call or some procfs output. But looks like it's impossible for now. > Do we actually have an x32 per-task mode at all? If so, maybe we can > just remove it on top of Dmitry's series. Don't think so, x32 should be set upon exec and without Dima's series it is immutable I think.
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From: Cyrill Gorcunov <gorcunov@gmail.com> To: Andy Lutomirski <luto@amacapital.net> Cc: Dmitry Safonov <dsafonov@virtuozzo.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Dmitry Safonov <0x7f454c46@gmail.com>, Adam Borowski <kilobyte@angband.pl>, "linux-mm@kvack.org" <linux-mm@kvack.org>, Andrei Vagin <avagin@gmail.com>, Borislav Petkov <bp@suse.de>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de> Subject: [Q] Figuring out task mode Date: Tue, 21 Mar 2017 21:05:25 +0300 [thread overview] Message-ID: <20170321180525.GC21564@uranus.lan> (raw) In-Reply-To: <CALCETrXoxRBTon8+jrYcbruYVUZASwgd-kzH-A96DGvT7gLXVA@mail.gmail.com> /I renamed the mail's subject/ On Tue, Mar 21, 2017 at 10:45:57AM -0700, Andy Lutomirski wrote: > >> + task_pt_regs(current)->orig_ax |= __X32_SYSCALL_BIT; > >> current->thread.status &= ~TS_COMPAT; > > > > Hi! I must admit I didn't follow close the overall series (so can't > > comment much here :) but I have a slightly unrelated question -- is > > there a way to figure out if task is running in x32 mode say with > > some ptrace or procfs sign? > > You should be able to figure out of a *syscall* is x32 by simply > looking at bit 30 in the syscall number. (This is unlike i386, which > is currently not reflected in ptrace.) Yes, syscall number will help but from criu perpspective (until Dima's patches are merged into mainlie) we need to figure out if we can dump x32 tasks without running parasite code inside, ie via plain ptrace call or some procfs output. But looks like it's impossible for now. > Do we actually have an x32 per-task mode at all? If so, maybe we can > just remove it on top of Dmitry's series. Don't think so, x32 should be set upon exec and without Dima's series it is immutable I think. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-03-21 18:05 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-21 16:37 [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY() Dmitry Safonov 2017-03-21 16:37 ` Dmitry Safonov 2017-03-21 17:17 ` Cyrill Gorcunov 2017-03-21 17:17 ` Cyrill Gorcunov 2017-03-21 17:45 ` Andy Lutomirski 2017-03-21 17:45 ` Andy Lutomirski 2017-03-21 18:05 ` Cyrill Gorcunov [this message] 2017-03-21 18:05 ` [Q] Figuring out task mode Cyrill Gorcunov 2017-03-21 23:54 ` Andy Lutomirski 2017-03-21 23:54 ` Andy Lutomirski 2017-03-21 18:09 ` [PATCHv2] x86/mm: set x32 syscall bit in SET_PERSONALITY() Dmitry Safonov 2017-03-21 18:09 ` Dmitry Safonov 2017-03-21 18:40 ` Cyrill Gorcunov 2017-03-21 18:40 ` Cyrill Gorcunov 2017-03-21 18:51 ` hpa 2017-03-21 18:51 ` hpa 2017-03-21 19:07 ` Cyrill Gorcunov 2017-03-21 19:07 ` Cyrill Gorcunov 2017-03-21 19:20 ` hpa 2017-03-21 19:20 ` hpa 2017-03-21 19:19 ` Dmitry Safonov 2017-03-21 19:19 ` Dmitry Safonov 2017-03-21 19:24 ` Cyrill Gorcunov 2017-03-21 19:24 ` Cyrill Gorcunov 2017-03-21 19:34 ` Dmitry Safonov 2017-03-21 19:34 ` Dmitry Safonov 2017-03-21 19:31 ` Andy Lutomirski 2017-03-21 19:31 ` Andy Lutomirski 2017-03-21 19:34 ` Cyrill Gorcunov 2017-03-21 19:34 ` Cyrill Gorcunov 2017-03-21 19:42 ` Dmitry Safonov 2017-03-21 19:42 ` Dmitry Safonov 2017-03-21 20:04 ` Dmitry Safonov 2017-03-21 20:04 ` Dmitry Safonov 2017-03-21 18:49 ` hpa 2017-03-21 18:49 ` hpa 2017-03-21 17:27 ` hpa 2017-03-21 17:27 ` hpa 2017-03-21 17:27 ` Dmitry Safonov 2017-03-21 17:27 ` Dmitry Safonov
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