From: Pavel Machek <pavel@ucw.cz>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>,
Randy Dunlap <rdunlap@infradead.org>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>
Subject: Re: [PATCH v12 1/8] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking
Date: Tue, 22 Sep 2020 00:52:51 +0200 [thread overview]
Message-ID: <20200921225251.GB13299@amd> (raw)
In-Reply-To: <c91021a9-adb0-8733-2423-f78dbea5c88a@intel.com>
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Hi!
> > +config X86_INTEL_BRANCH_TRACKING_USER
> > + prompt "Intel Indirect Branch Tracking for user-mode"
>
> Take the "Intel " and "INTEL_" out, please. It will only cause us all
> pain later if some of our x86 compatriots decide to implement this.
Are other x86 manufacturers legally allowed to implement that?
> > If the kernel is to be used only on older systems that do not support
> > IBT, and the size of the binary is important, you can save 900 KB by
> > disabling this feature.
> >
> > Otherwise, if unsure, say Y.
>
> 900k seems like a *lot*. Where the heck does that come from?
>
> Also, comments like that don't age very well. Consider:
>
> Support for this feature is only known to be present on Intel
> processors released in 2020 or later. This feature is also
> known to increase kernel text size substantially.
>
> If unsure, say N.
That is much better, thanks.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2020-09-21 22:52 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 19:23 [PATCH v12 0/8] Control-flow Enforcement: Indirect Branch Tracking Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 1/8] x86/cet/ibt: Add Kconfig option for user-mode " Yu-cheng Yu
2020-09-18 20:24 ` Randy Dunlap
2020-09-18 20:59 ` Pavel Machek
2020-09-18 21:08 ` H.J. Lu
2020-09-18 21:24 ` Pavel Machek
2020-09-18 21:36 ` H.J. Lu
2020-09-18 21:25 ` Yu, Yu-cheng
2020-09-18 21:40 ` Pavel Machek
2020-09-18 21:46 ` H.J. Lu
2020-09-18 22:03 ` Pavel Machek
2020-09-21 22:30 ` Yu, Yu-cheng
2020-09-21 22:41 ` Dave Hansen
2020-09-21 22:47 ` Yu, Yu-cheng
2020-09-21 22:54 ` Dave Hansen
2020-09-21 23:27 ` Yu, Yu-cheng
2020-09-21 22:52 ` Pavel Machek [this message]
2020-09-21 22:58 ` Dave Hansen
2020-09-18 19:23 ` [PATCH v12 2/8] x86/cet/ibt: User-mode Indirect Branch Tracking support Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 3/8] x86/cet/ibt: Handle signals for Indirect Branch Tracking Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 4/8] x86/cet/ibt: ELF header parsing " Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 5/8] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 6/8] x86/vdso/32: Add ENDBR32 to __kernel_vsyscall entry point Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 7/8] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2020-09-18 19:23 ` [PATCH v12 8/8] x86: Disallow vsyscall emulation when CET is enabled Yu-cheng Yu
2020-09-18 19:32 ` Dave Hansen
2020-09-18 21:00 ` Pavel Machek
2020-09-18 21:06 ` H.J. Lu
2020-09-18 21:17 ` Dave Hansen
2020-09-18 21:22 ` H.J. Lu
2020-09-18 21:28 ` Dave Hansen
2020-09-18 21:21 ` Yu, Yu-cheng
2020-09-18 21:22 ` Pavel Machek
2020-09-19 0:11 ` Andy Lutomirski
2020-09-21 16:22 ` Yu, Yu-cheng
2020-09-21 22:37 ` Yu-cheng Yu
2020-09-21 23:48 ` Andy Lutomirski
2020-09-22 17:45 ` Yu, Yu-cheng
2020-09-23 21:34 ` Andy Lutomirski
2020-09-23 22:07 ` Yu, Yu-cheng
2020-09-23 21:29 ` Sean Christopherson
2020-09-23 22:06 ` Yu, Yu-cheng
2020-09-23 22:08 ` Dave Hansen
2020-09-23 22:20 ` Yu, Yu-cheng
2020-09-23 22:47 ` Andy Lutomirski
2020-09-23 22:53 ` Dave Hansen
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