From: Dmitry Safonov <dsafonov@virtuozzo.com>
To: <linux-kernel@vger.kernel.org>, <mingo@redhat.com>
Cc: <luto@amacapital.net>, <tglx@linutronix.de>, <hpa@zytor.com>,
<x86@kernel.org>, <0x7f454c46@gmail.com>, <oleg@redhat.com>,
<gorcunov@openvz.org>, <xemul@virtuozzo.com>,
<khorenko@virtuozzo.com>
Subject: Re: [PATCH 0/6] x86: 32-bit compatible C/R on x86_64
Date: Wed, 1 Jun 2016 16:15:14 +0300 [thread overview]
Message-ID: <37a5e070-f825-a735-aba0-890ab864a829@virtuozzo.com> (raw)
In-Reply-To: <1464786697-20639-1-git-send-email-dsafonov@virtuozzo.com>
On 06/01/2016 04:11 PM, Dmitry Safonov wrote:
> This patches set is an attempt to add checkpoint/restore
> for 32-bit tasks in compatibility mode on x86_64 hosts.
>
> Restore in CRIU starts from one root restoring process, which
> reads info for all threads being restored from images files.
> This information is used further to to find out which processes
> share some resources. Later shared resources are restored only
> by one process and all other inherit them.
> After that it calls clone() and new threads restore their
> properties in parallel. Those threads inherit all parent's
> mappings and fetch properties from those mappings
> (and do clone themself, if they have children/subthreads). [1]
> Then starts restorer blob's play, it's PIE binary, which
> unmaps all unneeded for restoring VMAs, maps new VMAs and
> finalize restoring with sigreturn syscall. [2]
>
> To restore of 32-bit task we need three things to do in running
> x86_64 restorer blob:
> a) set code selector to __USER32_CS (to run 32-bit code);
> b) remap vdso blob from 64-bit to 32-bit
> This is primary needed because restore may happen on a different
> kernel, which has different vDSO image than we had on dump.
> c) if 32-bit vDSO differ to dumped image, move it on free place
> and add jump trampolines to that place.
> d) switch TIF_IA32 flag, so kernel would know that it deals with
> compatible 32-bit application.
>
> From all this:
> a) setting CS may be done from userspace, no patches needed;
> b) patches 1-3 add ability to map different vDSO blobs on x86 kernel;
> c) for remapping/moving 32-bit vDSO blob patches have been send earlier
> and seems to be accepted [3]
> d) and for swapping TIF_IA32 flag discussion with Andy ended in conclusion
> that it's better to remove this flag completely.
> Patches 4-6 deletes usage of TIF_IA32 from ptrace, signal and coredump
> code. This is rework/resend of RFC [4]
>
> [1] https://criu.org/Checkpoint/Restore#Restore
> [2] https://criu.org/Restorer_context
> [3] https://lkml.org/lkml/2016/5/17/243
> [4] https://lkml.org/lkml/2016/4/25/650
>
> Dmitry Safonov (6):
> x86/vdso: unmap vdso blob on vvar mapping failure
> x86/vdso: introduce do_map_vdso() and vdso_type enum
> x86/arch_prctl/vdso: add ARCH_MAP_VDSO_*
> x86/coredump: use core regs, rather that TIF_IA32 flag
> x86/ptrace: down with test_thread_flag(TIF_IA32)
> x86/signal: add SA_{X32,IA32}_ABI sa_flags
Oh, forgot to mention: this patches set is based on [3],
so kernel build bot may be not happy about applying them.
Anyway, I hope for the next revisions, the base-patches
will be applied to linux-next and build-bot will test them
just fine.
>
> arch/x86/entry/vdso/vma.c | 72 +++++++++++++++++++++-----------------
> arch/x86/ia32/ia32_signal.c | 2 +-
> arch/x86/include/asm/compat.h | 8 ++---
> arch/x86/include/asm/fpu/signal.h | 6 ++++
> arch/x86/include/asm/vdso.h | 4 +++
> arch/x86/include/uapi/asm/prctl.h | 6 ++++
> arch/x86/include/uapi/asm/signal.h | 6 +++-
> arch/x86/kernel/process_64.c | 10 ++++++
> arch/x86/kernel/ptrace.c | 2 +-
> arch/x86/kernel/signal.c | 19 +++++-----
> arch/x86/kernel/signal_compat.c | 30 ++++++++++++++--
> fs/binfmt_elf.c | 18 +++++-----
> kernel/signal.c | 5 +++
> 13 files changed, 129 insertions(+), 59 deletions(-)
>
--
Regards,
Dmitry Safonov
prev parent reply other threads:[~2016-06-01 13:16 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 13:11 [PATCH 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
2016-06-01 13:11 ` [PATCH 1/6] x86/vdso: unmap vdso blob on vvar mapping failure Dmitry Safonov
2016-06-01 13:11 ` [PATCH 2/6] x86/vdso: introduce do_map_vdso() and vdso_type enum Dmitry Safonov
2016-06-03 9:50 ` Cyrill Gorcunov
2016-06-03 10:03 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* Dmitry Safonov
2016-06-01 13:11 ` [PATCH 4/6] x86/coredump: use core regs, rather that TIF_IA32 flag Dmitry Safonov
2016-06-03 9:51 ` Cyrill Gorcunov
2016-06-03 9:56 ` Dmitry Safonov
2016-06-03 10:01 ` Cyrill Gorcunov
2016-06-06 20:45 ` Oleg Nesterov
2016-06-06 22:43 ` Oleg Nesterov
2016-06-08 13:28 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32) Dmitry Safonov
2016-06-03 9:57 ` Cyrill Gorcunov
2016-06-03 10:27 ` Dmitry Safonov
2016-06-03 10:41 ` Cyrill Gorcunov
2016-06-06 21:19 ` Oleg Nesterov
2016-06-07 11:38 ` Dmitry Safonov
2016-06-09 17:21 ` Andy Lutomirski
2016-06-10 20:07 ` Oleg Nesterov
2016-06-10 20:14 ` Andy Lutomirski
2016-06-13 13:50 ` Oleg Nesterov
2016-06-13 20:40 ` Andy Lutomirski
2016-06-14 14:34 ` Oleg Nesterov
2016-06-14 14:43 ` Dmitry Safonov
2016-06-01 13:11 ` [PATCH 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags Dmitry Safonov
2016-06-04 5:08 ` Andy Lutomirski
2016-06-04 15:57 ` Dmitry Safonov
2016-06-01 13:15 ` Dmitry Safonov [this message]
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=37a5e070-f825-a735-aba0-890ab864a829@virtuozzo.com \
--to=dsafonov@virtuozzo.com \
--cc=0x7f454c46@gmail.com \
--cc=gorcunov@openvz.org \
--cc=hpa@zytor.com \
--cc=khorenko@virtuozzo.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@redhat.com \
--cc=oleg@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=xemul@virtuozzo.com \
/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;
as well as URLs for NNTP newsgroup(s).