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From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Olivier Galibert <galibert@pobox.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Borislav Petkov <bp@alien8.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Andy Lutomirski <luto@kernel.org>, Willy Tarreau <w@1wt.eu>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
	Brian Gerst <brgerst@gmail.com>, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kees Cook <keescook@chromium.org>
Subject: Re: [RFC PATCH v2 6/6] x86/entry/pti: don't switch PGD on when pti_disable is set
Date: Thu, 11 Jan 2018 19:34:31 +0000	[thread overview]
Message-ID: <20180111193431.7e2d7f63@alans-desktop> (raw)
In-Reply-To: <20180111192601.cck3eq26vorybudk@treble>

On Thu, 11 Jan 2018 13:26:01 -0600
Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> On Thu, Jan 11, 2018 at 08:19:35PM +0100, Olivier Galibert wrote:
> > Wouldn't the time taken by an easy syscall like getuid be a clear indicator?  
> 
> I think only if you had a baseline measurement to compare against.

getuid can also be cached by a smart libc. getppid() is what micro
benchmarks seem to favour.

Alan

  reply	other threads:[~2018-01-11 19:35 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-09 12:56 [RFC PATCH v2 0/6] Per process PTI activation Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 1/6] x86/mm: add a pti_disable entry in mm_context_t Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 2/6] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI Willy Tarreau
2018-01-09 14:17   ` Borislav Petkov
2018-01-09 14:36     ` Willy Tarreau
2018-01-09 14:51       ` Borislav Petkov
2018-01-09 14:54         ` Willy Tarreau
2018-01-09 21:26           ` Andy Lutomirski
2018-01-09 21:29             ` Borislav Petkov
2018-01-09 21:32               ` Willy Tarreau
2018-01-09 21:46                 ` Borislav Petkov
2018-01-09 22:06                   ` Willy Tarreau
2018-01-09 22:20                     ` Borislav Petkov
2018-01-09 22:29                       ` Dave Hansen
2018-01-09 22:40                       ` Willy Tarreau
2018-01-10 14:42                         ` Borislav Petkov
2018-01-10 15:39                           ` Willy Tarreau
2018-01-10 16:09                             ` Borislav Petkov
2018-01-10 16:19                               ` Willy Tarreau
2018-01-10 17:28                                 ` Borislav Petkov
2018-01-10  7:31                       ` Ingo Molnar
2018-01-10  7:37                         ` Willy Tarreau
2018-01-10  7:59                           ` Ingo Molnar
2018-01-09 23:53                     ` Andy Lutomirski
2018-01-10  4:25                       ` Willy Tarreau
2018-01-10  7:25               ` Ingo Molnar
2018-01-10 14:45                 ` Borislav Petkov
2018-01-10 15:43                   ` Willy Tarreau
2018-01-10 15:45                   ` Ingo Molnar
2018-01-09 21:34             ` Kees Cook
2018-01-09 21:41             ` Willy Tarreau
2018-01-09 21:50               ` Kees Cook
2018-01-09 22:03                 ` Willy Tarreau
2018-01-10  7:13             ` Ingo Molnar
2018-01-12 15:03   ` David Laight
2018-01-12 15:06     ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 3/6] x86/pti: add a per-cpu variable pti_disable Willy Tarreau
2018-01-10  7:19   ` Ingo Molnar
2018-01-10  7:29     ` Willy Tarreau
2018-01-10  8:01       ` Ingo Molnar
2018-01-10  8:50         ` Willy Tarreau
2018-01-10  8:59           ` Ingo Molnar
2018-01-10  9:00             ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 4/6] x86/pti: don't mark the user PGD with _PAGE_NX Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 5/6] x86/entry/pti: avoid setting CR3 when it's already correct Willy Tarreau
2018-01-10  7:16   ` Ingo Molnar
2018-01-10  7:18     ` Willy Tarreau
2018-01-10 20:29   ` Dave Hansen
2018-01-11  6:46     ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 6/6] x86/entry/pti: don't switch PGD on when pti_disable is set Willy Tarreau
2018-01-10  7:15   ` Ingo Molnar
2018-01-10  7:23     ` Willy Tarreau
2018-01-10  8:22   ` Peter Zijlstra
2018-01-10  9:11     ` Willy Tarreau
2018-01-10 19:21       ` Andy Lutomirski
2018-01-10 19:39         ` Willy Tarreau
2018-01-10 19:44           ` Andy Lutomirski
2018-01-10 19:50         ` Linus Torvalds
2018-01-10 20:04           ` Andy Lutomirski
2018-01-11  6:42           ` Willy Tarreau
2018-01-11 15:29             ` Dave Hansen
2018-01-11 15:44               ` Willy Tarreau
2018-01-11 15:51                 ` Dave Hansen
2018-01-11 17:02                   ` Andy Lutomirski
2018-01-11 18:21                     ` Alexei Starovoitov
2018-01-11 18:30                       ` Dave Hansen
2018-01-11 18:32                       ` Josh Poimboeuf
2018-01-11 18:36                         ` Linus Torvalds
2018-01-11 18:38                         ` Dave Hansen
2018-01-11 18:51                           ` Linus Torvalds
2018-01-11 18:57                             ` Dave Hansen
2018-01-11 19:05                               ` Josh Poimboeuf
2018-01-11 19:07                               ` Borislav Petkov
2018-01-11 19:17                                 ` Dave Hansen
2018-01-11 19:19                                   ` Olivier Galibert
2018-01-11 19:26                                     ` Josh Poimboeuf
2018-01-11 19:34                                       ` Alan Cox [this message]
2018-01-11 21:23                                         ` Willy Tarreau
2018-01-11 21:28                                           ` Linus Torvalds
2018-01-11 22:06                                             ` Willy Tarreau
2018-01-12 16:37                                               ` David Laight
2018-01-11 19:12                               ` Linus Torvalds
2018-01-11 19:38                               ` Alexei Starovoitov
2018-01-11 19:11                           ` Willy Tarreau
2018-01-11 20:00                     ` Dave Hansen
2018-01-11 17:09                 ` Andy Lutomirski
2018-01-11 17:40                   ` Willy Tarreau
2018-01-11 17:53                     ` Andy Lutomirski
2018-01-11 18:05                       ` Willy Tarreau
2018-01-11 18:15                         ` Dave Hansen
2018-01-11 18:31                           ` Linus Torvalds
2018-01-11 18:25                     ` Linus Torvalds
2018-01-11 18:26                       ` Linus Torvalds
2018-01-11 19:33                         ` Andy Lutomirski
2018-01-12 20:22                           ` Ingo Molnar
2018-01-12 21:18                             ` Andy Lutomirski
2018-01-12 21:54                               ` Willy Tarreau
2018-01-11 21:59                       ` Willy Tarreau
2018-01-12 16:27                       ` David Laight
2018-01-12 17:55                         ` Linus Torvalds
2018-01-12 19:36                           ` Willy Tarreau
2018-01-11 18:35                 ` Dave Hansen
2018-01-11 21:49                   ` Willy Tarreau
2018-01-11 23:11 Alexey Dobriyan

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