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From: Matthew Wilcox <willy@infradead.org>
To: Igor Stoppa <igor.stoppa@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Mimi Zohar <zohar@linux.vnet.ibm.com>,
	igor.stoppa@huawei.com, Nadav Amit <nadav.amit@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	linux-integrity@vger.kernel.org,
	kernel-hardening@lists.openwall.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/12] __wr_after_init: x86_64: __wr_op
Date: Thu, 20 Dec 2018 11:27:53 -0800	[thread overview]
Message-ID: <20181220192753.GZ10600@bombadil.infradead.org> (raw)
In-Reply-To: <d5e8523a-3afd-d992-1af3-b329985c5ed5@gmail.com>

On Thu, Dec 20, 2018 at 09:19:15PM +0200, Igor Stoppa wrote:
> On 20/12/2018 20:49, Matthew Wilcox wrote:
> > I think you're causing yourself more headaches by implementing this "op"
> > function.
> 
> I probably misinterpreted the initial criticism on my first patchset, about
> duplication. Somehow, I'm still thinking to the endgame of having
> higher-level functions, like list management.
> 
> > Here's some generic code:
> 
> thank you, I have one question, below
> 
> > void *wr_memcpy(void *dst, void *src, unsigned int len)
> > {
> > 	wr_state_t wr_state;
> > 	void *wr_poking_addr = __wr_addr(dst);
> > 
> > 	local_irq_disable();
> > 	wr_enable(&wr_state);
> > 	__wr_memcpy(wr_poking_addr, src, len);
> 
> Is __wraddr() invoked inside wm_memcpy() instead of being invoked privately
> within __wr_memcpy() because the code is generic, or is there some other
> reason?

I was assuming that __wr_addr() might be costly, and we were trying to
minimise the number of instructions executed while write-rare was enabled.


  reply	other threads:[~2018-12-20 19:28 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-19 21:33 [RFC v2 PATCH 0/12] hardening: statically allocated protected memory Igor Stoppa
2018-12-19 21:33 ` [PATCH 01/12] x86_64: memset_user() Igor Stoppa
2018-12-19 21:33 ` [PATCH 02/12] __wr_after_init: linker section and label Igor Stoppa
2018-12-19 21:33 ` [PATCH 03/12] __wr_after_init: generic header Igor Stoppa
2018-12-21 19:38   ` Nadav Amit
2018-12-21 19:45     ` Matthew Wilcox
2018-12-23  2:28       ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 04/12] __wr_after_init: x86_64: __wr_op Igor Stoppa
2018-12-20 16:53   ` Igor Stoppa
2018-12-20 17:20   ` Thiago Jung Bauermann
2018-12-20 17:46     ` Igor Stoppa
2018-12-20 18:49   ` Matthew Wilcox
2018-12-20 19:19     ` Igor Stoppa
2018-12-20 19:27       ` Matthew Wilcox [this message]
2018-12-21 17:23       ` Andy Lutomirski
2018-12-21 17:42         ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 05/12] __wr_after_init: x86_64: debug writes Igor Stoppa
2018-12-19 21:33 ` [PATCH 06/12] __wr_after_init: Documentation: self-protection Igor Stoppa
2018-12-19 21:33 ` [PATCH 07/12] __wr_after_init: lkdtm test Igor Stoppa
2018-12-19 21:33 ` [PATCH 08/12] rodata_test: refactor tests Igor Stoppa
2018-12-19 21:33 ` [PATCH 09/12] rodata_test: add verification for __wr_after_init Igor Stoppa
2018-12-19 21:33 ` [PATCH 10/12] __wr_after_init: test write rare functionality Igor Stoppa
2018-12-19 21:33 ` [PATCH 11/12] IMA: turn ima_policy_flags into __wr_after_init Igor Stoppa
2018-12-20 17:30   ` Thiago Jung Bauermann
2018-12-20 17:49     ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 12/12] x86_64: __clear_user as case of __memset_user Igor Stoppa

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