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From: Nadav Amit <namit@vmware.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Damian Tometzki <linux_dti@icloud.com>,
	linux-integrity <linux-integrity@vger.kernel.org>,
	linux-security-module <linux-security-module@vger.kernel.org>,
	Andy Lutomirski <luto@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v5 02/10] x86/jump_label: Use text_poke_early() during early init
Date: Tue, 20 Nov 2018 18:47:11 +0000	[thread overview]
Message-ID: <B1CCA937-6595-4430-B1CB-7833CD303BDB@vmware.com> (raw)
In-Reply-To: <34f7e083-218e-dbdf-73ca-47dd11e750cc@zytor.com>

> On Nov 20, 2018, at 10:23 AM, H. Peter Anvin <hpa@zytor.com> wrote:
> 
> On 11/20/18 10:18 AM, Peter Zijlstra wrote:
>>> Can't we make this test in text_poke() directly, please?
>> 
>> He does that in 9/10 iirc.
> 
> No, in 9/10 he does that change locally for the jump_label, but there is
> absolutely no reason not to do that test in text_poke() proper, and
> simply use text_poke() everywhere in the kernel.

The decision in __jump_label_transform() is between text_poke_early() and
text_poke_bp() ( and not text_poke() ).

Moveover, text_poke_early() is also used when a module is loaded - a
decision which based on the “init" argument.

For these two reasons, I don’t see how the change you proposed can be
performed.


  reply	other threads:[~2018-11-20 18:47 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13 13:07 [PATCH v5 00/10] x86/alternative: text_poke() fixes Nadav Amit
2018-11-13 13:07 ` [PATCH v5 01/10] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Nadav Amit
2018-11-13 13:07 ` [PATCH v5 02/10] x86/jump_label: Use text_poke_early() during early init Nadav Amit
2018-11-20 18:10   ` H. Peter Anvin
2018-11-20 18:18     ` Peter Zijlstra
2018-11-20 18:23       ` H. Peter Anvin
2018-11-20 18:47         ` Nadav Amit [this message]
2018-11-13 13:07 ` [PATCH v5 03/10] x86/mm: temporary mm struct Nadav Amit
2018-11-13 13:07 ` [PATCH v5 04/10] fork: provide a function for copying init_mm Nadav Amit
2018-11-13 13:07 ` [PATCH v5 05/10] x86/alternative: initializing temporary mm for patching Nadav Amit
2018-11-13 13:07 ` [PATCH v5 06/10] x86/alternative: use temporary mm for text poking Nadav Amit
2018-11-13 13:07 ` [PATCH v5 07/10] x86/kgdb: avoid redundant comparison of patched code Nadav Amit
2018-11-13 13:07 ` [PATCH v5 08/10] x86: avoid W^X being broken during modules loading Nadav Amit
2018-11-13 13:07 ` [PATCH v5 09/10] x86/jump-label: remove support for custom poker Nadav Amit
2018-11-13 13:07 ` [PATCH v5 10/10] x86/alternative: remove the return value of text_poke_*() Nadav Amit
2018-11-20 12:42 ` [PATCH v5 00/10] x86/alternative: text_poke() fixes Peter Zijlstra
2018-11-20 18:52   ` Nadav Amit

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