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From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Lutomirski <luto@kernel.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	mhiramat@kernel.org, jbaron@akamai.com,
	Jiri Kosina <jkosina@suse.cz>,
	David.Laight@aculab.com, bp@alien8.de, julia@ni.com,
	jeyu@kernel.org, Peter Anvin <hpa@zytor.com>
Subject: Re: [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64
Date: Thu, 29 Nov 2018 13:47:25 -0500	[thread overview]
Message-ID: <20181129134725.6d86ade6@gandalf.local.home> (raw)
In-Reply-To: <CAHk-=wigLUgxDM6Dq2aS7efduffratP976Ggmpv4Ev4EOrJxyA@mail.gmail.com>

On Thu, 29 Nov 2018 10:23:44 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, Nov 29, 2018 at 9:59 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Do you realize that the cmpxchg used by the first attempts of the
> > dynamic modification of code by ftrace was the source of the e1000e
> > NVRAM corruption bug.  
> 
> If you have a static call in IO memory, you have bigger problems than that.
> 
> What's your point?

Just that cmpxchg on dynamic modified code brings back bad memories ;-)

> 
> Again - I will point out that the things you guys have tried to come
> up with have been *WORSE*. Much worse.

Note, we do have a bit of control at what is getting called. The patch
set requires that the callers are wrapped in macros. We should not
allow just any random callers (like from asm).

This isn't about modifying any function call. This is for a specific
subset, that we can impose rules on.

-- Steve


  reply	other threads:[~2018-11-29 18:47 UTC|newest]

Thread overview: 120+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-26 13:54 [PATCH v2 0/4] Static calls Josh Poimboeuf
2018-11-26 13:54 ` [PATCH v2 1/4] compiler.h: Make __ADDRESSABLE() symbol truly unique Josh Poimboeuf
2018-11-27  8:49   ` Ard Biesheuvel
2018-11-26 13:54 ` [PATCH v2 2/4] static_call: Add static call infrastructure Josh Poimboeuf
2018-11-26 13:54 ` [PATCH v2 3/4] x86/static_call: Add out-of-line static call implementation Josh Poimboeuf
2018-11-26 15:43   ` Peter Zijlstra
2018-11-26 16:19     ` Steven Rostedt
2018-11-26 13:55 ` [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64 Josh Poimboeuf
2018-11-26 16:02   ` Peter Zijlstra
2018-11-26 17:10     ` Josh Poimboeuf
2018-11-26 17:56       ` Josh Poimboeuf
2018-11-26 20:00         ` Peter Zijlstra
2018-11-26 20:08         ` Peter Zijlstra
2018-11-26 21:26           ` Josh Poimboeuf
2018-11-27  8:43             ` Peter Zijlstra
2018-11-27  8:50               ` Peter Zijlstra
2018-11-29  6:05               ` Andy Lutomirski
2018-11-29  9:42                 ` Peter Zijlstra
2018-11-29 13:11                   ` Josh Poimboeuf
2018-11-29 13:37                   ` Andy Lutomirski
2018-11-29 14:38                     ` Peter Zijlstra
2018-11-29 14:42                       ` Jiri Kosina
2018-11-29 16:33                       ` Josh Poimboeuf
2018-11-29 16:49                         ` Peter Zijlstra
2018-11-29 16:59                           ` Andy Lutomirski
2018-11-29 17:10                             ` Josh Poimboeuf
2018-11-29 22:01                               ` Peter Zijlstra
2018-11-29 22:14                                 ` Josh Poimboeuf
2018-11-29 22:22                                   ` Peter Zijlstra
2018-11-29 22:25                                     ` Andy Lutomirski
2018-11-29 22:30                                       ` Josh Poimboeuf
2018-11-29 17:15                             ` Peter Zijlstra
2018-11-29 17:20                               ` Steven Rostedt
2018-11-29 17:21                                 ` Steven Rostedt
2018-11-29 17:41                                   ` Andy Lutomirski
2018-11-29 17:45                                     ` Josh Poimboeuf
2018-11-29 17:52                                       ` Andy Lutomirski
2018-11-29 17:49                                     ` Steven Rostedt
2018-11-29 18:37                               ` Josh Poimboeuf
2018-11-29 16:50                         ` Linus Torvalds
2018-11-29 16:55                           ` Steven Rostedt
2018-11-29 17:02                           ` Andy Lutomirski
2018-11-29 17:07                             ` Peter Zijlstra
2018-11-29 17:31                               ` Andy Lutomirski
2018-11-29 17:35                                 ` Jiri Kosina
2018-11-29 17:13                             ` Steven Rostedt
2018-11-29 17:35                               ` Linus Torvalds
2018-11-29 17:44                                 ` Steven Rostedt
2018-11-29 17:50                                   ` Linus Torvalds
2018-11-29 17:54                                     ` Linus Torvalds
2018-11-29 17:58                                     ` Steven Rostedt
2018-11-29 18:23                                       ` Linus Torvalds
2018-11-29 18:47                                         ` Steven Rostedt [this message]
2018-11-29 18:58                                           ` Linus Torvalds
2018-11-29 19:08                                             ` Linus Torvalds
2018-11-29 19:11                                               ` Linus Torvalds
2018-12-10 23:58                                                 ` Pavel Machek
2018-12-11  1:43                                                   ` Linus Torvalds
2018-11-29 19:12                                               ` Steven Rostedt
2018-11-29 19:27                                               ` Andy Lutomirski
2018-11-29 20:24                                                 ` Josh Poimboeuf
2018-11-29 22:17                                                   ` Josh Poimboeuf
2018-11-29 23:04                                                   ` Linus Torvalds
2018-11-30 16:27                                                     ` Josh Poimboeuf
2018-12-11  9:41                                                       ` David Laight
2018-12-11 17:19                                                         ` Josh Poimboeuf
2018-12-12 18:29                                                     ` Josh Poimboeuf
2018-11-30 16:42                                                   ` Andy Lutomirski
2018-11-30 18:39                                                     ` Josh Poimboeuf
2018-11-30 19:45                                                       ` Linus Torvalds
2018-11-30 20:18                                                         ` Andy Lutomirski
2018-11-30 20:28                                                           ` Steven Rostedt
2018-11-30 20:59                                                             ` Andy Lutomirski
2018-11-30 21:01                                                               ` Steven Rostedt
2018-11-30 21:13                                                               ` Jiri Kosina
2018-11-30 21:10                                                           ` Josh Poimboeuf
2018-11-29 19:16                                             ` Steven Rostedt
2018-11-29 19:22                                               ` Josh Poimboeuf
2018-11-29 19:27                                                 ` Steven Rostedt
2018-11-30 22:16                                                 ` Rasmus Villemoes
2018-11-30 22:24                                                   ` Josh Poimboeuf
2018-11-29 19:24                                               ` Linus Torvalds
2018-11-29 19:28                                                 ` Andy Lutomirski
2018-11-29 19:31                                                 ` Steven Rostedt
2018-11-29 20:12                                             ` Josh Poimboeuf
2018-11-29 18:00                                     ` Andy Lutomirski
2018-11-29 18:42                                       ` Linus Torvalds
2018-11-29 18:55                                       ` Steven Rostedt
2018-11-29 17:29                             ` Linus Torvalds
2018-11-29 17:35                               ` Andy Lutomirski
2018-11-26 18:28       ` Andy Lutomirski
2018-11-26 20:14         ` Josh Poimboeuf
2018-11-27  8:46           ` Peter Zijlstra
2018-11-26 16:08   ` Peter Zijlstra
2018-11-26 16:11     ` Ard Biesheuvel
2018-11-26 16:33       ` Andy Lutomirski
2018-11-26 16:39       ` Peter Zijlstra
2018-11-26 16:44         ` Josh Poimboeuf
2018-11-26 14:01 ` [PATCH v2 0/4] Static calls Josh Poimboeuf
2018-11-26 20:54 ` Steven Rostedt
2018-11-26 22:24   ` Josh Poimboeuf
2018-11-26 22:53     ` Steven Rostedt
2018-12-04 23:08 ` Steven Rostedt
2018-12-04 23:41   ` Andy Lutomirski
2018-12-05 15:04     ` Josh Poimboeuf
2018-12-05 23:36       ` Andy Lutomirski
2018-12-07 16:06 ` Edward Cree
2018-12-07 16:49   ` Edward Cree
2018-12-11 18:05   ` Josh Poimboeuf
2018-12-12  5:59     ` Nadav Amit
2018-12-12 17:11       ` Edward Cree
2018-12-12 17:47         ` [RFC/WIP PATCH 0/2] dynamic calls Edward Cree
2018-12-12 17:50           ` [RFC PATCH 1/2] static_call: fix out-of-line static call implementation Edward Cree
2018-12-12 17:52           ` [RFC PATCH 2/2] net: core: rather hacky PoC implementation of dynamic calls Edward Cree
2018-12-12 18:14         ` [PATCH v2 0/4] Static calls Nadav Amit
2018-12-12 18:33           ` Edward Cree
2018-12-12 21:15             ` Nadav Amit
2018-12-12 21:36               ` Edward Cree
2018-12-12 21:45                 ` Nadav Amit
2018-12-10 23:57 ` Pavel Machek

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