From: Andrey Savchenko <bircoph@altlinux.org>
To: ALT Linux Team development discussions <devel@lists.altlinux.org>
Subject: Re: [devel] I: LTO in %optflags by default
Date: Wed, 25 Aug 2021 10:32:35 +0300
Message-ID: <20210825103235.63f0b8a5d7611d16d0fc3b3c@altlinux.org> (raw)
In-Reply-To: <20210825100339.41800b67@homerun.localdomain>
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On Wed, 25 Aug 2021 10:03:39 +0300 Denis Medvedev wrote:
> В Wed, 25 Aug 2021 09:53:29 +0300
> Andrey Savchenko <bircoph@altlinux.org> пишет:
>
> > On Wed, 25 Aug 2021 08:46:40 +0300 Denis Medvedev wrote:
> > > В Wed, 25 Aug 2021 09:27:50 +0400
> > > "Ivan A. Melnikov" <iv@altlinux.org> пишет:
> > >
> > > > On Tue, Aug 24, 2021 at 09:20:50PM +0300, Dmitry V. Levin wrote:
> > > > > Hi,
> > > > >
> > > > > Пришло время включить в Сизифе LTO (link-time optimization).
> > > > > К сожалению, ещё не все пакеты собираются с этой оптимизацией,
> > > > > некоторые предстоит исправить.
> > > >
> > > > Скажите, а как это влияет на время сборки пакетов?
> > > >
> > > > Это тестировалось только на основных архитектурах? На всех?
> > > >
> > >
> > > Я, конечно, понимаю, что запоздал с этим,
> > > но можно ли включить
> > > по умолчаниию заодно вот это:
> > >
> > >
> > > -mmitigate-rop
> > > Attempt to compile code without unintended return addresses, making
> > > ROP just a little harder.
> > >
> > > -mindirect-branch=thunk -mfunction-return=thunk
> > > Enables retpoline (return trampolines) to mitigate some variants of
> > > Spectre V2. The second flag is necessary on Skylake+ due to the
> > > fact that the branch target buffer is vulnerable.
> >
> > Но эти опции, ведь, не на всех архитектурах нужны, даже в основной
> > сборочнице. Поэтому если и включать, то выборочно в зависимости от
> > архитектуры.
> >
> > > -fstack-protector-all -Wstack-protector --param ssp-buffer-size=4
> > > choice of "-fstack-protector" does not protect all functions . You
> > > need -fstack-protector-all to guarantee guards are applied to all
> > > functions, although this will likely incur a performance penalty.
> > > Consider -fstack-protector-strong as a middle ground. The
> > > -Wstack-protector flag here gives warnings for any functions that
> > > aren't going to get protected.
> > >
> > > -fstack-clash-protection
> > > Defeats a class of attacks called stack clashing.
> >
> > Эта может поломать много приложений и может быть значимый удар по
> > производительности.
> >
> > > -Wl,-z,relro,-z,now
> > > RELRO (read-only relocation). The options relro & now specified
> > > together are known as "Full RELRO". You can specify "Partial RELRO"
> > > by omitting the now flag. RELRO marks various ELF memory sections
> > > readonly (E.g. the GOT).
> >
> > С точки зрения безопасности это хорошо, а вот тормоза даёт дикие,
> > особенно на тяжёлых приложениях типа LO. Возможно, в этом есть смысл
> > в специальных ветках, но в Сизиф такое не нужно тянуть.
> В таком случае как мне правильно сделать дефолты для особых веток?
> Сделать свою версию какого пакета?
rpmbuild, нужно править макрос(ы) %optflags_* в platform.in; думаю,
%optflags_default должно хватить.
Best regards,
Andrew Savchenko
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next prev parent reply other threads:[~2021-08-25 7:32 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 18:20 Dmitry V. Levin
2021-08-24 18:21 ` Dmitry V. Levin
2021-08-24 18:22 ` Dmitry V. Levin
2021-08-25 0:04 ` Dmitry V. Levin
2021-08-25 8:18 ` Vitaly Lipatov
2021-08-25 8:28 ` Ivan A. Melnikov
2021-08-25 8:38 ` Vitaly Lipatov
2021-08-25 9:18 ` Andrey Savchenko
2021-08-25 17:14 ` [devel] devel-static Dmitry V. Levin
2021-08-25 17:25 ` Alexey Sheplyakov
2021-08-25 19:19 ` Andrey Savchenko
2021-08-25 19:14 ` Andrey Savchenko
2021-08-25 19:58 ` Vitaly Lipatov
2021-08-25 20:52 ` Andrey Savchenko
2021-08-25 21:06 ` Vitaly Lipatov
2021-08-25 21:36 ` Andrey Savchenko
2021-08-27 19:43 ` [devel] Статические библиотеки и thin LTO (Was: I: LTO in %optflags by default) Alexey Sheplyakov
2021-08-27 22:18 ` [devel] Статические библиотеки и thin LTO Vitaly Chikunov
2021-08-29 6:34 ` Alexey Sheplyakov
2021-08-30 9:18 ` Dmitry V. Levin
2021-08-30 9:30 ` Andrey Savchenko
2021-08-30 9:39 ` Dmitry V. Levin
2021-08-30 14:36 ` Andrey Savchenko
2021-08-30 9:50 ` Arseny Maslennikov
2021-08-24 18:23 ` [devel] I: LTO in %optflags by default Dmitry V. Levin
2021-08-24 19:19 ` Dmitry V. Levin
2021-08-25 0:33 ` Dmitry V. Levin
2021-08-26 6:00 ` [devel] I: LTO in %optflags by defaulta (top-level asm) Vitaly Chikunov
2021-08-25 5:27 ` [devel] I: LTO in %optflags by default Ivan A. Melnikov
2021-08-25 5:46 ` Denis Medvedev
2021-08-25 5:50 ` Denis Medvedev
2021-08-25 6:53 ` Andrey Savchenko
2021-08-25 7:03 ` Denis Medvedev
2021-08-25 7:32 ` Andrey Savchenko [this message]
2021-08-26 18:43 ` Michael Shigorin
2021-08-25 7:12 ` Ivan A. Melnikov
2021-08-25 8:14 ` Alexey Tourbin
2021-08-25 8:39 ` Andrey Savchenko
2021-08-25 7:12 ` Alexey Sheplyakov
2021-08-25 16:28 ` Dmitry V. Levin
2021-08-25 17:48 ` Dmitry V. Levin
2021-08-25 7:37 ` Alexey Sheplyakov
2021-08-25 18:07 ` [devel] Administrivia Dmitry V. Levin
2021-08-25 19:25 ` Alexey Sheplyakov
2021-08-25 20:03 ` Alexey V. Vissarionov
2021-08-26 19:02 ` [devel] Administrivii Michael Shigorin
2021-08-26 19:18 ` [devel] debugedit Dmitry V. Levin
2021-10-13 9:16 ` [devel] debugedit DWARF version 0 Denis Medvedev
2021-10-13 9:51 ` Dmitry V. Levin
2021-10-13 9:51 ` Denis Medvedev
2021-08-25 19:27 ` [devel] I: LTO in %optflags by default Andrey Savchenko
2021-08-25 23:54 ` Dmitry V. Levin
2021-08-26 9:35 ` Alexey V. Vissarionov
2021-08-26 19:33 ` Andrey Savchenko
2021-08-27 0:37 ` Dmitry V. Levin
2021-08-27 8:07 ` Sergey V Turchin
2021-08-27 9:11 ` Alexey V. Vissarionov
2021-08-27 10:00 ` Alexey Sheplyakov
2021-08-27 12:54 ` Dmitry V. Levin
2021-08-25 10:45 ` Vitaly Lipatov
2021-08-25 16:20 ` Dmitry V. Levin
2021-08-25 20:23 ` Vitaly Lipatov
2021-08-25 20:30 ` Dmitry V. Levin
2021-08-25 21:24 ` Dmitry V. Levin
2021-08-25 23:07 ` Aleksey Novodvorsky
2021-08-25 23:19 ` Dmitry V. Levin
2021-08-25 23:54 ` Andrey Savchenko
2021-08-26 0:04 ` Dmitry V. Levin
2021-08-26 6:39 ` Andrey Savchenko
2021-08-26 7:25 ` Vitaly Lipatov
2021-08-27 0:20 ` Dmitry V. Levin
2021-08-26 9:40 ` Alexey V. Vissarionov
2021-08-26 4:23 ` alexei
2021-08-26 8:24 ` Dmitry V. Levin
2021-08-26 0:26 ` Dmitry V. Levin
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